CN115968394A - Ink composition containing luminescent particles, light conversion layer and light-emitting element - Google Patents

Ink composition containing luminescent particles, light conversion layer and light-emitting element Download PDF

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CN115968394A
CN115968394A CN202180052227.9A CN202180052227A CN115968394A CN 115968394 A CN115968394 A CN 115968394A CN 202180052227 A CN202180052227 A CN 202180052227A CN 115968394 A CN115968394 A CN 115968394A
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light
group
ink composition
emitting
meth
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延藤浩一
乙木荣志
三木崇之
利光麻里子
小林方大
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DIC Corp
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DIC Corp
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D11/00—Inks
    • C09D11/30—Inkjet printing inks
    • C09D11/38—Inkjet printing inks characterised by non-macromolecular additives other than solvents, pigments or dyes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
    • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D11/00—Inks
    • C09D11/30—Inkjet printing inks
    • C09D11/32—Inkjet printing inks characterised by colouring agents
    • C09D11/322—Pigment inks
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D11/00—Inks
    • C09D11/30—Inkjet printing inks
    • C09D11/32—Inkjet printing inks characterised by colouring agents
    • C09D11/324—Inkjet printing inks characterised by colouring agents containing carbon black
    • C09D11/326—Inkjet printing inks characterised by colouring agents containing carbon black characterised by the pigment dispersant
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/02—Use of particular materials as binders, particle coatings or suspension media therefor
    • C09K11/025—Use of particular materials as binders, particle coatings or suspension media therefor non-luminescent particle coatings or suspension media
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/66—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing germanium, tin or lead
    • C09K11/664—Halogenides
    • C09K11/665—Halogenides with alkali or alkaline earth metals
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/02—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of crystals, e.g. rock-salt, semi-conductors
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/20—Filters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y20/00—Nanooptics, e.g. quantum optics or photonic crystals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K2102/00—Constructional details relating to the organic devices covered by this subclass
    • H10K2102/301—Details of OLEDs
    • H10K2102/331—Nanoparticles used in non-emissive layers, e.g. in packaging layer
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/30—Devices specially adapted for multicolour light emission
    • H10K59/38—Devices specially adapted for multicolour light emission comprising colour filters or colour changing media [CCM]

Abstract

The invention aims to: provided are an ink composition containing light-emitting particles, which has excellent storage stability and can form a cured product having excellent thermal stability, and a light conversion layer and a light-emitting element using the ink composition. The ink composition containing luminescent particles of the present invention is characterized by containing: the light-emitting material comprises nanoparticles comprising luminescent nanocrystals, a photopolymerizable compound, a photopolymerization initiator and an antioxidant, wherein the photopolymerization initiator comprises 2 or more types of acylphosphine oxide compounds, and the antioxidant comprises 1 or more types of compounds selected from the group consisting of a compound having a hydroxyphenyl group and a compound having a phosphite structure.

Description

Ink composition containing light-emitting particles, light conversion layer, and light-emitting element
Technical Field
The present invention relates to an ink composition containing light-emitting particles, a light conversion layer, and a light-emitting element.
Background
Conventionally, a color filter pixel portion in a display such as a liquid crystal display device is manufactured by photolithography using a curable resist material containing, for example, red organic pigment particles or green organic pigment particles, and an alkali-soluble resin and/or an acrylic monomer.
In recent years, low power consumption of displays has been strongly demanded, and studies have been actively made on a color filter pixel unit that extracts red light or green light using luminescent nanoparticles such as quantum dots, quantum rods, or other inorganic phosphor particles instead of the red organic pigment particles or the green organic pigment particles.
However, the above method for manufacturing a color filter by photolithography has the following disadvantages according to the characteristics of the manufacturing method: resist material other than the pixel portion containing the more expensive semiconductor nanocrystals may be wasted. Under such circumstances, in order to avoid the waste of the resist material as described above, it has been studied to form a pixel portion of a photoelectric conversion substrate by an ink jet method (patent document 1).
The nanoparticles containing the semiconductor nanocrystals are characterized by emitting fluorescence or phosphorescence and having a narrow half-value width of emission wavelength. CdSe was originally used as the semiconductor nanocrystal, but in order to avoid the harmful effects thereof, semiconductor nanocrystals of InP having a perovskite structure have recently come to be used. As a semiconductor nanocrystal having a perovskite structure, for example, csPbX is known 3 (X is a halogen element and represents Cl, br or I).
Among them, the semiconductor nanocrystal having a perovskite structure has an advantage of excellent productivity because the emission wavelength can be controlled by adjusting the kind and the existing ratio of the halogen element. Further, for example, a composition containing a luminescent crystal having a perovskite structure and a solid polymer derived from an acrylate polymer, and a luminescent component are disclosed (patent document 2). Further, a film (light conversion layer) obtained by curing a composition containing fluorescent particles of a perovskite compound, a photopolymerizable compound, a photopolymerization initiator, and an antioxidant is disclosed (patent document 3).
However, the composition disclosed in patent document 3 has a small content of photopolymerization initiator in the composition, and thus the actually obtained light conversion layer is not sufficiently cured. Therefore, there are the following disadvantages: when the light conversion layer is heated, the luminescent crystal having the perovskite structure included in the light conversion layer deteriorates due to thermal oxidation, and thus the reduction in the emission intensity cannot be suppressed. On the other hand, if the content of the photopolymerization initiator is increased in order to obtain a sufficiently cured light conversion layer, there are the following disadvantages: the viscosity of the ink of the composition increases, or precipitation occurs due to the photopolymerization initiator, which results in a decrease in the storage stability of the ink.
Documents of the prior art
Patent literature
Patent document 1: international publication No. 2008/001693
Patent document 2: international publication No. 2018/028870
Patent document 3: japanese patent laid-open No. 2020-70374
Disclosure of Invention
Problems to be solved by the invention
The invention aims to: provided are an ink composition containing luminescent particles, which has excellent storage stability and can form a cured product with excellent thermal stability, and a light conversion layer and a light-emitting element using the ink composition.
Means for solving the problems
In order to solve the above problems, the present invention has focused on a nanoparticle-containing ink composition containing a photopolymerizable compound, a photopolymerization initiator, and an antioxidant, and has repeatedly conducted extensive studies, and as a result, has found that: the present inventors have completed the present invention by finding that an ink composition using 2 or more specific compounds as a photopolymerization initiator and an antioxidant containing a specific compound has excellent storage stability and can form a photocured product having excellent thermal stability.
That is, the present invention provides an ink composition containing luminescent particles, comprising: the light-emitting semiconductor device comprises nanoparticles comprising a semiconductor nanocrystal comprising a metal halide and having a light-emitting property, a photopolymerizable compound, a photopolymerization initiator, and an antioxidant, wherein the photopolymerization initiator contains 2 or more types of acylphosphine oxide compounds, and the antioxidant contains 1 or more types of compounds selected from the group consisting of a compound having a hydroxyphenyl group and a compound having a phosphite structure.
Further, the present invention provides a light conversion layer composed of a cured product of the ink composition containing nanoparticles including semiconductor nanocrystals, and a light-emitting element using the light conversion layer.
Effects of the invention
According to the present invention, an ink composition containing nanoparticles including semiconductor nanocrystals, which has excellent storage stability and can form a cured product having excellent thermal stability, a light conversion layer using the ink composition, and a light-emitting element can be provided.
Drawings
FIG. 1 is a sectional view showing an embodiment of a method for producing nanoparticles containing semiconductor nanocrystals according to the present invention.
FIG. 2 is a sectional view showing another embodiment of the semiconductor nanocrystal-containing nanoparticle of the present invention. (a) The hollow particles contain light-emitting particles, and (b) the polymer-coated light-emitting particles.
FIG. 3 is a sectional view showing another embodiment of the nanoparticle including a semiconductor nanocrystal of the present invention. (a) The term "silica-coated light-emitting particle" means a light-emitting particle coated with silica, and the term "polymer-coated light-emitting particle" means a light-emitting particle coated with polymer.
FIG. 4 is a cross-sectional view showing one embodiment of a light-emitting element of the present invention.
FIG. 5 is a schematic diagram showing the structure of an active matrix circuit.
Fig. 6 is a schematic diagram showing the configuration of an active matrix circuit.
Detailed Description
Hereinafter, an ink composition containing nanoparticles including semiconductor nanocrystals, a method for producing the same, and a light-emitting element according to the present invention will be described in detail based on preferred embodiments shown in the drawings. Fig. 1 is a sectional view showing one embodiment of a method for producing nanoparticles containing semiconductor nanocrystals according to the present invention. An example of production when hollow silica particles are used as the hollow particles is shown. In fig. 1, the hollow particle 912 to which the nanocrystal material is added on the lower stage is not shown in the fine hole 912 b. Fig. 2 and 3 are cross-sectional views showing another configuration example of the nanoparticles.
1. Ink compositions containing nanoparticles comprising semiconductor nanocrystals
An ink composition containing nanoparticles including semiconductor nanocrystals according to an embodiment of the present invention contains: a photopolymerizable compound, at least 2 or more photopolymerization initiators, and at least 1 or more antioxidants. The ink composition containing nanoparticles including semiconductor nanocrystals according to one embodiment can be suitably used for forming a light conversion layer of a light-emitting display element using organic EL by an inkjet method, as described below. The ink composition is preferably prepared and used in a manner more suitable for the inkjet method than the photolithography method, since a material such as nanoparticles containing relatively expensive and luminescent semiconductor nanocrystals or a photopolymerizable compound is not wasted, and a pixel portion (light conversion layer) can be formed only by using a necessary amount of a desired portion.
Since the ink composition contains 2 or more photopolymerization initiators, the ink composition can be sufficiently cured, that is, the amount of the photopolymerization initiator can be reduced, even when the amount of the photopolymerization initiator added is small, compared to the case of using 1 kind of photopolymerization initiator. Therefore, the ink composition can ensure solubility of the photopolymerization initiator in the photopolymerizable compound, and thus can suppress an increase in ink viscosity and precipitation caused by the photopolymerization initiator. Therefore, the ink composition can have excellent storage stability. In addition, in general, the ink composition may undergo a reaction of a photopolymerizable compound by a catalyst action of a photopolymerization initiator during storage, thereby increasing the ink viscosity. In contrast, the ink composition of the present invention contains a specific antioxidant, and therefore can further suppress an increase in ink viscosity. Further, according to the ink composition, since the light conversion layer can be formed by sufficiently curing even when the amount of the photopolymerization initiator added is small, when the light conversion layer is heated, the nanoparticles containing luminescent nanocrystals can be prevented from being deteriorated by thermal oxidation, and the reduction in the emission intensity can be prevented. Further, since the ink composition contains the antioxidant, the thermal oxidation can be more reliably suppressed. Therefore, the light conversion layer obtained from the above ink composition can obtain excellent external quantum efficiency, in other words, can obtain excellent thermal stability.
The ink composition containing nanoparticles including semiconductor nanocrystals according to the present embodiment and the constituent components thereof will be described below with reference to an inkjet ink composition for forming a color filter pixel portion constituting a light conversion layer. The constituent components include nanoparticles of semiconductor nanocrystals, photopolymerizable compounds, photopolymerization initiators, and antioxidants, as well as ligands, light diffusing particles, polymer dispersants, and the like.
1-1. Nanoparticles comprising semiconductor nanocrystals
The nanoparticle containing a semiconductor nanocrystal in the present invention means, for example, a nanoparticle containing a semiconductor nanocrystal having a luminescence property that can emit light (fluorescence or phosphorescence) having a wavelength different from an absorbed wavelength by absorbing light having a specific wavelength. That is, the light-emitting property is preferably a property of emitting light by excitation of electrons, and more preferably a property of emitting light by excitation of electrons with excitation light. The luminescent nanocrystals may be red luminescent nanocrystals emitting light having a luminescence peak wavelength in the range of 605 to 665nm (red light), green luminescent nanocrystals emitting light having a luminescence peak wavelength in the range of 500 to 560nm (green light), or blue luminescent nanocrystal particles emitting light having a luminescence peak wavelength in the range of 420 to 480nm (blue light).
The semiconductor nanocrystal having a light emitting property may be a light emitting nanocrystal particle (light emitting semiconductor nanocrystal) including a semiconductor material. Examples of the semiconductor nanocrystal having a light-emitting property include a quantum dot, a quantum rod, and the like. Among them, quantum dots are preferable from the viewpoint of easy control of emission spectra, reduction in production cost while ensuring reliability, and improvement in mass productivity. Further, the luminescent nanocrystal is preferably a quantum dot composed of a metal halide, from the viewpoint that a luminescent peak having a narrower half-value width can be obtained. In the present embodiment, a nanoparticle composed of a quantum dot containing a metal halide is described below, but the present invention is not limited thereto, and various nanoparticles containing a semiconductor nanocrystal having a light-emitting property can be applied.
1-1-1. Hollow particle-encapsulated luminescent particle
The nanoparticle including a semiconductor nanocrystal according to the present invention is provided with, as the light-emitting particle 91 shown in fig. 1 (hereinafter, also referred to as "hollow particle-included light-emitting particle 91"),: a hollow particle 912 having a hollow portion 912a and a pore 912b communicating with the hollow portion 912a, and a semiconductor nanocrystal 911 (hereinafter, also referred to simply as "nanocrystal 911") which is accommodated in the hollow portion 912a, is composed of a metal halide, and has a light emitting property. The light-emitting particles 91 can be obtained by, for example, precipitating nanocrystals 911 in the hollow portions 912a of the hollow particles 912. Since the nanocrystals 911 are protected by the hollow particles 912, the luminescent particles 91 can have excellent stability against heat and oxygen, and as a result, excellent luminescent characteristics can be obtained.
The light-emitting particles 91 are more preferably light-emitting particles 90 having a polymer layer 92 made of a hydrophobic polymer on the surface thereof (hereinafter, sometimes referred to as "polymer-coated light-emitting particles"). By providing the polymer layer 92, the polymer-coated light-emitting particles 90 can have further improved stability against heat and oxygen, and can have excellent particle dispersibility, and thus can have more excellent light-emitting characteristics when used as a light conversion layer.
< nanocrystal 911 >
The nanocrystal 911 is a nano-sized crystal (nanocrystal particle) composed of a metal halide and emitting fluorescence or phosphorescence by absorbing excitation light. The nanocrystal 911 is, for example, a crystal having a maximum particle diameter of 100nm or less as measured by a transmission electron microscope or a scanning electron microscope. The nanocrystals 911 can be excited by light energy or electric energy of a specific wavelength to emit fluorescence or phosphorescence, for example.
Nanocrystals 91 composed of metal halides are of the general formula: a. The a M b X c The compound represented.
Wherein A is at least 1 of an organic cation and a metal cation. Examples of the organic cation include ammonium, formamidinium, guanidinium, imidazolium, pyridinium, pyrrolidinium, and protonated thiourea, and examples of the metal cation include cations such as Cs, rb, K, na, and Li.
M is at least 1 metal cation. The metal cation includes metal cations selected from groups 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14 and 15. More preferred examples include: ag. And cations such as Au, bi, ca, ce, co, cr, cu, eu, fe, ga, ge, hf, in, ir, mg, mn, mo, na, nb, nd, ni, os, pb, pd, pt, re, rh, ru, sb, sc, sm, sn, sr, ta, te, ti, V, W, zn, zr and the like.
X is at least 1 anion. Examples of anions include: chloride ion, bromide ion, iodide ion, cyanide ion, and the like.
a is 1 to 7, b is 1 to 4, c is 3 to 16.
The nanocrystal 911 can control the emission wavelength (emission color) by adjusting the particle size, the kind and the existence ratio of the anion constituting the X site.
Specifically, the general formula A a M m X x The compound is preferably AMX or A 4 MX、AMX 2 、AMX 3 、A 2 MX 3 、AM 2 X 3 、A 2 MX 4 、A 2 MX 5 、A 3 MX 5 、A 3 M 2 X 5 、A 3 MX 6 、A 4 MX 6 、AM 2 X 6 、A 2 MX 6 、A 4 M 2 X 6 、A 3 MX 8 、A 3 M 2 X 9 、A 3 M 3 X 9 、A 2 M 2 X 10 、A 7 M 3 X 16 The compounds represented.
Wherein A is at least 1 of an organic cation and a metal cation. As the organic cation, there may be mentioned: ammonium, formamidinium, guanidinium, imidazolium, pyridinium, pyrrolidinium, protonated thiourea, etc., and examples of the metal cation include ions such as Cs, rb, K, na, li, etc.
Wherein M is at least 1 metal cation. Specifically, there may be mentioned: 1 metal cation (M) 1 ) 2 metal cations (M) 1 α M 2 β ) 3 metal cations (M) 1 α M 2 β M 3 γ ) 4 metal cations (M) 1 α M 2 β M 3 γ M 4 δ ) And so on. Wherein α, β, γ, and δ represent real numbers of 0 to 1, respectively, and represent α + β + γ + δ =1. The metal cation includes metal cations selected from groups 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14 and 15. More preferred examples include: ag. And cations such as Au, bi, ca, ce, co, cr, cu, eu, fe, ga, ge, hf, in, ir, mg, mn, mo, na, nb, nd, ni, os, pb, pd, pt, re, rh, ru, sb, sc, sm, sn, sr, ta, te, ti, V, W, zn, zr and the like.
Wherein X is an anion comprising at least 1 halogen. Specifically, 1 kind of halogen anion (X) can be exemplified 1 ) 2 halogen anions (X) 1 α X 2 β ) And the like. Examples of the anion include chloride ion, bromide ion, iodide ion, cyanide ion, and the like, and at least 1 kind of halide ion is contained.
From the above general formula A a M m X x The compound composed of a metal halide may be a compound to which metal ions such as Bi, mn, ca, eu, sb, yb, and the like are added (doped) to improve the light-emitting characteristics.
With respect to the above general formula A a M m X x Among the compounds composed of metal halides, compounds having a perovskite crystal structure are particularly preferably used in the form of semiconductor nanocrystals, because the emission wavelength (emission color) can be controlled by adjusting the particle size, the type and the proportion of metal cations constituting the M site, and the type and the proportion of anions constituting the X site. In particular, AMX is preferred 3 、A 3 MX 5 、A 3 MX 6 、A 4 MX 6 、A 2 MX 6 The compounds represented. Wherein A, M and X are as defined above. As described above, the compound having a perovskite crystal structure may be added (doped) with metal ions such as Bi, mn, ca, eu, sb, and Yb.
In order to exhibit further excellent light-emitting characteristics, it is preferable that a is Cs, rb, K, na, or Li, and M is 1 metal cation (M) in the compound having a perovskite crystal structure 1 ) Or 2 metal cations (M) 1 α M 2 β ) And X is chloride ion, bromide ion or iodide ion. Where α and β represent real numbers of 0 to 1, respectively, and represent α + β =1. Specifically, M is preferably selected from Ag, au, bi, cu, eu, fe, ge, K, in, na, mn, pb, pd, sb, si, sn, yb, zn, zr.
As a nano-sized material composed of a metal halide and having a perovskite-type crystal structureSpecific composition of crystal 911, csPbBr 3 、CH 3 NH 3 PbBr 3 、CHN 2 H 4 PbBr 3 And the like, the nanocrystal 911 using Pb as M is preferable because of excellent light intensity and excellent quantum efficiency. In addition, csSnBr 3 、CsSnCl 3 、CsSnBr 1.5 Cl 1.5 、Cs 3 Sb 2 Br 9 、(CH 3 NH 3 ) 3 Bi 2 Br 9 、(C 4 H 9 NH 3 ) 2 AgBiBr 6 And the like, the nanocrystal 911 using a metal cation other than Pb as M is preferable because of low toxicity and less influence on the environment.
As the nanocrystal 911, the following crystals can be selected for use: a red light-emitting crystal that emits light having a light emission peak in a wavelength range of 605 to 665nm (red light); a green light-emitting crystal which emits light having a light emission peak in a wavelength range of 500 to 560nm (green light); and a blue light-emitting crystal which emits light having a light-emitting peak in a wavelength range of 420 to 480nm (blue light). In one embodiment, a plurality of such nanocrystals may be used in combination.
The wavelength of the emission peak of the nanocrystal 911 can be confirmed, for example, by a fluorescence spectrum or a phosphorescence spectrum measured by using an absolute PL quantum yield measurement device.
The red-emitting nanocrystal 911 preferably has a luminescence peak in a wavelength range of 665nm or less, 663nm or less, 660nm or less, 658nm or less, 655nm or less, 653nm or less, 651nm or less, 650nm or less, 647nm or less, 645nm or less, 643nm or less, 640nm or less, 637nm or less, 635nm or less, 632nm or less, or 630nm or less, and preferably has a luminescence peak in a wavelength range of 628nm or more, 625nm or more, 623nm or more, 620nm or more, 615nm or more, 610nm or more, 607nm or more, or 605nm or more.
These upper and lower limits may be arbitrarily combined. In the following description, the upper limit and the lower limit described individually may be arbitrarily combined.
The green-emitting nanocrystal 911 preferably has an emission peak in a wavelength range of 560nm or less, 557nm or less, 555nm or less, 550nm or less, 547nm or less, 545nm or less, 543nm or less, 540nm or less, 537nm or less, 535nm or less, 532nm or less, or 530nm or less, and preferably has an emission peak in a wavelength range of 528nm or more, 525nm or more, 523nm or more, 520nm or more, 515nm or more, 510nm or more, 507nm or more, 505nm or more, 503nm or more, or 500nm or more.
The blue-emitting nanocrystal 911 preferably has an emission peak in a wavelength range of 480nm or less, 477nm or less, 475nm or less, 470nm or less, 467nm or less, 465nm or less, 463nm or less, 460nm or less, 457nm or less, 455nm or less, 452nm or less, or 450nm or less, and preferably has an emission peak in a wavelength range of 450nm or more, 445nm or more, 440nm or more, 435nm or more, 430nm or more, 428nm or more, 425nm or more, 422nm or more, or 420nm or more.
The shape of the nanocrystal 911 is not particularly limited, and may be any geometric shape or any irregular shape. Examples of the shape of the nanocrystal 911 include a rectangular parallelepiped shape, a cubic shape, a spherical shape, a regular tetrahedral shape, an elliptical shape, a pyramidal shape, a disk shape, a branched shape, a mesh shape, and a rod shape. The shape of the nanocrystal 911 is preferably a rectangular parallelepiped shape, a cubic shape, or a spherical shape.
The average particle diameter (volume average diameter) of the nanocrystal 911 is preferably 40nm or less, more preferably 30nm or less, and still more preferably 20nm or less. The average particle size of the nanocrystal 911 is preferably 1nm or more, more preferably 1.5nm or more, and still more preferably 2nm or more. The nanocrystal 911 having the above average particle size is preferable because it easily emits light of a desired wavelength. The average particle diameter of the nanocrystal 911 is obtained by measuring with a transmission electron microscope or a scanning electron microscope and calculating the volume average diameter.
< hollow particles 912 >
The hollow particles 912 may include a hollow portion 912a and pores 912b, the hollow portion 912a may be a space in which the nanocrystals 911 can be accommodated, and the pores 912b may communicate with the hollow portion 912a, and particles having an overall shape such as a rectangular parallelepiped shape, a cubic shape, a spherical shape (substantially true spherical shape), an elongated spherical shape (elliptical spherical shape), or a honeycomb shape (a shape in which cylinders having a hexagonal cross section and open both ends are arranged without a gap) may be used. The hollow particles having a rectangular parallelepiped shape, a cubic shape, a substantially true sphere shape, or an ellipsoidal shape are particles having a balloon structure or a hollow structure. These hollow particles having a balloon structure or a hollow structure are more preferable because stability against heat and oxygen can be more reliably obtained by covering the entirety of the nanocrystals 911 housed in the hollow portion 912 a. Further, in the luminescent nanoparticles 90 obtained, since the hollow particles 912 are interposed between the polymer layers 92 described later, the stability of the nanocrystals 911 with respect to oxygen and moisture is also improved.
The hollow portion 912a may accommodate 1 nanocrystal 911, or may accommodate a plurality of nanocrystals 911. In addition, the hollow portion 912a may be occupied entirely by 1 or more nanocrystals 911, or may be occupied only partially.
The hollow particles may be made of any material as long as the nanocrystals 911 can be protected. From the viewpoint of ease of synthesis, transmittance, cost, and the like, the hollow particles are preferably hollow silica particles, hollow alumina particles, hollow titanium oxide particles, which are hollow inorganic nanoparticles; or hollow polystyrene particles or hollow PMMA particles as hollow polymer particles, and more preferably hollow silica particles or hollow alumina particles. From the viewpoint of ease of surface treatment of the particles, hollow silica particles are more preferable.
The average outer diameter of the hollow particles 912 is not particularly limited, but is preferably 5 to 300nm, more preferably 6 to 100nm, still more preferably 8 to 50nm, and particularly preferably 10 to 25nm. With the hollow particles 912 having such a size, the stability of the nanocrystals 911 against oxygen, moisture, and heat can be sufficiently improved.
The average inner diameter of the hollow particles 912, i.e., the diameter of the hollow portion 912a is not particularly limited, but is preferably 1 to 250nm, more preferably 2 to 100nm, still more preferably 3 to 50nm, and particularly preferably 5 to 15nm. When the average inner diameter of the hollow particles 912 is too small, the nanocrystals 911 may not be deposited in the hollow portion 912a, and when the average inner diameter of the hollow particles 912 is too large, the nanocrystals 911 may be excessively aggregated in the hollow portion 91a, thereby lowering the light emission efficiency. The hollow particles 912 having an average inner diameter in the above range can precipitate the nanocrystals 911 while suppressing aggregation.
The size of the fine pores 912b is not particularly limited, but is preferably 0.5 to 10nm, and more preferably 1 to 5nm. In this case, the solution containing the raw material compound of the nanocrystal 911 can smoothly and reliably permeate into the hollow portion 912 a.
The hollow silica particles, which are an example of the hollow particles 912, can be produced, for example, as shown in fig. 1, by the following steps: (a) A step of mixing a copolymer (X) containing an aliphatic polyamide chain (X1) having a primary amino group and/or a secondary amino group and a hydrophobic organic chain (X2) with an aqueous medium to form an aggregate (XA) composed of a core mainly composed of the hydrophobic organic chain (X2) and a shell mainly composed of the aliphatic polyamide chain (X1); (b) A step in which a silica raw material (Y) is added to an aqueous medium containing an association (XA), and a sol-gel reaction of the silica raw material (Y) is carried out using the association (XA) as a mold (template), thereby precipitating silica to obtain core-shell silica nanoparticles (YA); and (c) removing the copolymer (X) from the core-shell silica nanoparticles (YA).
Examples of the aliphatic polyamine chain (x 1) include: polyethylene imine chains, polyallylamine chains, and the like. In order to efficiently produce core-shell silica nanoparticles (YA) which are precursors of the hollow silica nanoparticles 912, polyethylene imine chains are more preferable. In order to balance the molecular weight of the hydrophobic organic segment (x 2), the molecular weight of the aliphatic polyamine chain (x 1) is preferably in the range of 5 to 10,000, more preferably 10 to 8,000 in terms of the number of repeating units.
The molecular structure of the aliphatic polyamine chain (x 1) is also not particularly limited, and examples thereof include straight-chain, branched, dendritic, star-like, comb-like, and the like. The branched polyethyleneimine chain is preferable from the viewpoints of efficient formation of an associated body which becomes a mold during silica precipitation, production cost, and the like.
Examples of the hydrophobic organic segment (x 2) include: the segment derived from an alkyl compound may be derived from a hydrophobic polymer such as polyacrylate, polystyrene, or polyurethane.
In the case of the alkyl compound, a compound having an alkylene chain having 5 or more carbon atoms is preferable, and a compound having an alkylene chain having 10 or more carbon atoms is more preferable. The chain length of the hydrophobic organic segment (x 2) is not particularly limited as long as it is within a range in which the associated body (XA) is stable in a nanometer size, and the number of repeating units is preferably within a range of 5 to 10,000, more preferably within a range of 5 to 1,000.
The hydrophobic organic segment (x 2) may be bonded to the end of the aliphatic polyamide chain (x 1) by coupling, or may be bonded to the middle of the aliphatic polyamide chain (x 1) by grafting. The 1 aliphatic polyamine chain (x 1) may be bonded with only 1 hydrophobic organic segment (x 2) or may be bonded with a plurality of hydrophobic organic segments (x 2).
The ratio of the aliphatic polyamide chain (X1) to the hydrophobic organic segment (X2) contained in the copolymer (X) is not particularly limited as long as an association (XA) stable in an aqueous medium can be formed. Specifically, the proportion of the aliphatic polyamide chain (x 1) is preferably in the range of 10 to 90% by mass, more preferably in the range of 30 to 70% by mass, and still more preferably in the range of 40 to 60% by mass.
In the step (a), the copolymer (X) is dissolved in an aqueous medium, whereby the aggregates (XA) having a core-shell structure can be formed by self-organization. The core of the aggregate (XA) is mainly composed of the hydrophobic organic segment (x 2), and the shell layer is mainly composed of the aliphatic polyamine chain (x 1), and it is considered that the aggregate (XA) stable in an aqueous medium is formed by hydrophobic interaction of the hydrophobic organic segment (x 2). Examples of the aqueous medium include: water, a mixed solution of water and a water-soluble solvent, and the like. When the mixed solution is used, the amount of water contained in the mixed solution is preferably 0.5/9.5 to 3/7, more preferably 0.1/9.9 to 5/5, in terms of a volume ratio, with respect to the water-soluble solvent. From the viewpoint of productivity, environment, cost, and the like, it is preferable to use water alone or a mixed solution of water and alcohol.
The amount of the copolymer (X) contained in the aqueous medium is preferably 0.05 to 15% by mass, more preferably 0.1 to 10% by mass, and still more preferably 0.2 to 5% by mass. When the copolymer (X) is self-organized in the aqueous medium to form the association body (XA), the aliphatic polyamide chain (X1) may be crosslinked in the shell layer using an organic crosslinkable compound having 2 or more functional groups. Examples of the organic crosslinkable compound include: aldehyde-containing compounds, epoxy-containing compounds, unsaturated double bond-containing compounds, carboxylic acid group-containing compounds, and the like.
Next, a sol-gel reaction of the silica raw material (Y) is performed in the presence of water using the aggregate (XA) as a mold. Examples of the silica raw material (Y) include water glass, tetraalkoxysilanes, and oligomers such as tetraalkoxysilanes. Examples of tetraalkoxysilanes include: tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, tetra-t-butoxysilane, and the like. Examples of the oligomers include: tetramethoxysilane tetramers, tetramethoxysilane heptamers, tetraethoxysilane pentamers, tetraethoxysilane decamers, and the like.
The sol-gel reaction does not occur in the continuous phase of the solvent, and proceeds selectively only on the association body (XA). Therefore, the reaction conditions may be arbitrarily set within the range where the associated body (XA) is not crushed. In the sol-gel reaction, the ratio of the association body (XA) to the silica raw material (Y) may be appropriately set.
The temperature of the sol-gel reaction is not particularly limited, but is preferably in the range of 0 to 90 ℃, more preferably in the range of 10 to 40 ℃, and still more preferably in the range of 15 to 30 ℃. In this case, the core-shell silica nanoparticles (YA) can be obtained efficiently.
In the case of the silica raw material (Y) having a high reactivity, the time of the sol-gel reaction is preferably in the range of 1 minute to 24 hours, and more preferably in the range of 30 minutes to 5 hours. In the case of the silica raw material (Y) having a low reactivity, the sol-gel reaction time is preferably 5 hours or more, and more preferably one week.
By the step (b), core-shell silica nanoparticles (YA) having a uniform particle diameter without mutual aggregation can be obtained. The particle size distribution of the obtained core-shell silica nanoparticles (YA) varies depending on the production conditions and the target particle size, and may be set to ± 15% or less, preferably ± 10% or less, with respect to the target particle size (average particle size).
In the core-shell silica nanoparticles (YA), the core is mainly composed of a hydrophobic organic segment (x 2), and the shell is a composite body mainly composed of an aliphatic polyamide chain (x 1) and silica. Here, the main component means that the intentional 3 rd component is not included. The shell layer of the core-shell silica nanoparticles (YA) is an organic-inorganic composite in which a matrix made of silica and an aliphatic polyamide chain (x 1) are combined.
The particle diameter of the core-shell silica nanoparticles (YA) is preferably 5 to 300nm, more preferably 6 to 100nm, still more preferably 8 to 50nm, and particularly preferably 10 to 25nm. The particle diameter can be adjusted by the kind, composition and molecular weight of the copolymer (X), the kind of the silica raw material (Y), the sol-gel reaction conditions, and the like. The core-shell silica nanoparticles (YA) are extremely excellent in monodispersity because of their self-organization of molecules, and the width of the particle size distribution can be ± 15% or less of the average particle size.
The core-shell silica nanoparticles (YA) may be spherical or elongated spherical with an aspect ratio of 2 or more. Further, core-shell silica nanoparticles (YA) having a plurality of cores in one particle can also be produced. The shape, structure, and the like of the particles can be adjusted by changing the composition of the copolymer (X), the type of the silica raw material (Y), the sol-gel reaction conditions, and the like.
The amount of silica contained in the core-shell silica nanoparticles (YA) is preferably in the range of 30 to 95 mass%, and more preferably in the range of 60 to 90 mass%. The amount of silica can be adjusted by changing the amount of the aliphatic polyamide chain (X1) contained in the copolymer (X), the amount of the association (XA), the kind and amount of the silica raw material (Y), the sol-gel reaction time, the temperature, and the like.
Next, in the step (c), the copolymer (X) is removed from the core-shell silica nanoparticles (YA), thereby obtaining the desired hollow silica nanoparticles 912.
Examples of the method for removing the copolymer (X) include a firing treatment and a treatment of washing with a solvent, and from the viewpoint of the removal rate of the copolymer (X), a firing treatment method in a firing furnace is preferable. Examples of the firing treatment include: high-temperature firing in the presence of air or oxygen, high-temperature firing in the presence of an inert gas (e.g., nitrogen or helium), and preferably high-temperature firing in air. The firing temperature is preferably 300 ℃ or higher, and more preferably in the range of 300 to 1000 ℃.
The hollow silica particles 912 can be produced in the above manner. Commercially available hollow silica particles 912 can also be used. Examples of the commercially available product include "SiliNax SP-PN (b)" manufactured by Nissan corporation. The hollow alumina particles, the hollow titania particles, or the hollow polymer particles can also be produced by the same method.
< method for producing hollow particle-encapsulated luminescent particle 91 >
In the present invention, the hollow particles thus obtained are impregnated with a solution (Z) containing a raw material compound of semiconductor nanocrystals ((d) in fig. 1) and dried, whereby luminescent perovskite-type semiconductor nanocrystals having a luminescence property ((d) in fig. 1) are deposited in the hollow portions 912a of the hollow particles, and luminescent particles (hollow-particle-encapsulated luminescent particles) 91 are obtained.
Further, the light-emitting particles 91 obtained as described above may be added to a photopolymerizable compound described later, specifically, for example, isobornyl methacrylate to prepare a dispersion containing the light-emitting particles 91.
The solution (Z) of the raw material compound containing semiconductor nanocrystals is preferably a solution having a solid content concentration of 0.5 to 20 mass% in terms of impregnation into the hollow particles 912. The organic solvent is only required to be a good solvent for the nanocrystal 911, and is particularly preferably dimethyl sulfoxide, N-dimethylformamide, N-methylformamide, ethanol, methanol, 2-propanol, γ -butyrolactone, ethyl acetate, water, or a mixed solvent thereof, from the viewpoint of compatibility.
In addition, as a method for preparing the solution, it is preferable to mix the raw material compound and the organic solvent in the reaction vessel under an inert gas atmosphere such as argon. The temperature condition in this case is preferably room temperature to 350 ℃, and the stirring time in the mixing is preferably 1 minute to 10 hours.
As for the raw material compound of the semiconductor nanocrystal, for example, when a cesium lead tribromide solution is prepared, cesium bromide and lead (II) bromide are preferably mixed with the above-mentioned organic solvent. In this case, the addition amounts of cesium bromide and lead (II) bromide are preferably adjusted to 0.5 to 200 parts by mass and 0.5 to 200 parts by mass, respectively, with respect to 1000 parts by mass of the good solvent.
Next, at room temperature, the hollow silica particles 912 were added to the reaction vessel, and the lead cesium tribromide solution was impregnated into the hollow portions 912a of the hollow silica particles 912. Then, the solution in the reaction solution is filtered to remove the excess lead cesium tribromide solution and recover solids. Then, the obtained solid is dried under reduced pressure at-50 to 200 ℃. By the above operation, the perovskite type semiconductor nanocrystal 911 can be precipitated in the hollow portion 912a of the hollow silica particle 911, and the light-emitting particle 91 can be obtained.
< variation of hollow particle-containing light-emitting particle 91 >
Further, as shown in fig. 2 (a), the hollow particle-encapsulated light-emitting particle 91 preferably includes an intermediate layer 913, and the intermediate layer 913 is located between the wall surface of the hollow portion 912a of the hollow particle 92 and the semiconductor nanocrystal 911 and is composed of a ligand coordinated to the surface of the semiconductor nanocrystal 911. The light-emitting particle 91 shown in fig. 2 (a) has an intermediate layer 913 formed by coordinating oleic acid, oleylamine, or the like as a ligand to the surface of a nanocrystal 911 containing Pb cations (indicated by black dots in the figure) as M sites. In fig. 2 (a), the pores 912b of the hollow particles 912 are not shown. The light-emitting particles 91 provided with the intermediate layer 913 can further improve the stability of the nanocrystals 911 against oxygen, moisture, heat, and the like, due to the intermediate layer 913.
The light-emitting particle 91 provided with the intermediate layer 913 composed of the ligand can be obtained by: a ligand is added in advance to a solution containing a raw material compound of the nanocrystal 911, and the solution is immersed in the hollow silica particle 912 and dried.
The ligand is preferably a compound having a bonding group to which the cation contained in nanocrystal 911 bonds. The bonding group is preferably at least 1 of a carboxyl group, a carboxylic anhydride group, an amino group, an ammonium group, a mercapto group, a phosphino group, a phosphinoxide group, a phosphoric acid group, a phosphonic acid group, a phosphinic acid group, a sulfonic acid group, and a boric acid group, and more preferably at least 1 of a carboxyl group and an amino group. The ligand includes compounds containing a carboxyl group or an amino group, and 1 kind of them may be used alone or 2 or more kinds may be used in combination.
Examples of the carboxyl group-containing compound include linear or branched aliphatic carboxylic acids having 1 to 30 carbon atoms. Specific examples of the carboxyl group-containing compound include: arachidonic acid, crotonic acid, trans-2-decenoic acid, erucic acid, 3-decenoic acid, cis-4, 7,10,13,16, 19-docosahexaenoic acid, 4-decenoic acid, all-cis-5, 8,11,14, 17-eicosapentaenoic acid, all-cis-8, 11, 14-eicosatrienoic acid, cis-9-hexadecenoic acid, trans-3-hexenoic acid, trans-2-hexenoic acid, 2-heptenoic acid, 3-heptenoic acid, 2-hexadecenoic acid, linolenic acid, linoleic acid, gamma-linolenic acid, 3-nonenoic acid, 2-nonenoic acid, trans-2-octenoic acid, petroselic acid, elaidic acid, oleic acid, 3-octenoic acid, trans-2-pentenoic acid trans-3-pentenoic acid, ricinoleic acid, sorbic acid, 2-tridecenoic acid, cis-15-tetracosenoic acid, 10-undecenoic acid, 2-undecenoic acid, acetic acid, butyric acid, behenic acid, cerotic acid, capric acid, eicosanoic acid, heneicosic acid, heptadecanoic acid, heptanoic acid, caproic acid, heptacosanoic acid, lauric acid, myristic acid, melissic acid, octacosanoic acid, nonadecanoic acid, n-caprylic acid, palmitic acid, pentadecanoic acid, propionic acid, pentacosanoic acid, pelargonic acid, stearic acid, tetracosanoic acid, tricosanoic acid, tridecanoic acid, undecanoic acid, valeric acid, and the like.
Examples of the amino group-containing compound include linear or branched aliphatic amines having 1 to 30 carbon atoms. Specific examples of the amino group-containing compound include: 1-aminoheptadecane, 1-aminononadecane, heptadecan-9-amine, stearylamine, oleylamine, 2-n-octyl-1-dodecylamine, allylamine, pentylamine, 2-ethoxyethylamine, 3-ethoxypropylamine, isobutylamine, isopentylamine, 3-methoxypropylamine, 2-methoxyethylamine, 2-methylbutylamine, neopentylamine, propylamine, methylamine, ethylamine, butylamine, hexylamine, heptylamine, n-octylamine, 1-aminodecane, nonanamine, 1-aminoundecane, dodecylamine, 1-aminopentadecane, 1-aminotridecane, hexadecylamine, tetradecylamine and the like.
In addition, in the production of the light-emitting particles 91, a ligand having a reactive group (for example, 3-aminopropyltrimethoxysilane) may be added to a solution of a raw material compound containing the nanocrystals 911. In this case, the mother particle 91 may be produced so as to have an intermediate layer 913, the intermediate layer 913 being located between the hollow particle 912 and the nanocrystal 911 as shown in fig. 2, and being composed of a ligand coordinated to the surface of the nanocrystal 911, and molecules of the ligand forming a siloxane bond with each other. With this configuration, the nanocrystals 911 can be more firmly fixed to the hollow particles 912 via the intermediate layer 913.
The ligand having a reactive group is preferably a compound having a bonding group that bonds with the cation included in the nanocrystal 911 and a reactive group that contains Si and forms a siloxane bond. The reactive group may react with the hollow particles 912.
Examples of the bonding group include: carboxyl group, carboxylic anhydride group, amino group, ammonium group, mercapto group, phosphino group, phosphinoxide group, phosphoric acid group, phosphonic acid group, phosphinic acid group, sulfonic acid group, boric acid group, and the like. Among them, the bonding group is preferably at least 1 of a carboxyl group and an amino group. These bonding groups have a higher affinity (reactivity) for the cations contained in the nanocrystal 911 than the reactive groups. Therefore, the ligand coordinates the bonding group to the nanocrystal 911 side, and the intermediate layer 913 can be formed more easily and reliably.
On the other hand, as the reactive group, a hydrolyzable silyl group such as a silanol group or an alkoxysilyl group having 1 to 6 carbon atoms is preferable in terms of easiness of formation of a siloxane bond.
Examples of such ligands include carboxyl-or amino-group-containing silicon compounds, and 1 or 2 or more of these may be used alone or in combination.
Specific examples of the carboxyl group-containing silicon compound include: trimethoxysilylpropionic acid, triethoxysilylpropionic acid, N- [3- (trimethoxysilyl) propyl ] -N ' -carboxymethylethylenediamine, N- [3- (trimethoxysilyl) propyl ] phthalamide, N- [3- (trimethoxysilyl) propyl ] ethylenediamine-N, N ', N ' -triacetic acid, and the like.
On the other hand, specific examples of the amino group-containing silicon compound include: 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethylethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldipropoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldiisopropoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltripropoxysilane, N- (2-aminoethyl) -3-aminopropyltriisopropoxysilane, N- (2-aminoethyl) -3-aminoisobutyldimethylmethoxysilane, N- (2-aminoethyl) -3-aminoisobutylmethyldimethoxysilane, N- (2-aminoethyl) -11-aminoundecyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylsilanetriol, 3-triethoxysilyl-N- (1, 3-dimethylbutylidene) N-phenylpropanamine-propylamine, N is added to the reaction solution to form a reaction solution, N-bis [3- (trimethoxysilyl) propyl ] ethylenediamine, (aminoethyl) phenyltrimethoxysilane, (aminoethyl) phenyltriethoxysilane, (aminoethyl) phenyltripropoxysilane, (aminoethyl) phenyltriisopropoxysilane, (aminoethyl-aminomethyl) phenyltrimethoxysilane, (aminoethyl-aminomethyl) phenyltriethoxysilane, (aminoethyl-aminomethyl) phenyltripropoxysilane, (aminoethyl-aminomethyl) phenyltriisopropoxysilane, N- (vinylbenzyl) -2-aminoethyl-3-aminopropyltrimethoxysilane, N- (vinylbenzyl) -2-aminoethyl-3-aminopropylmethyldimethoxysilane, N-beta- (N-vinylbenzylaminoethyl) -N-gamma- (N-vinylbenzyl) -gamma-aminopropyltrimethoxysilane, N-beta- (N-di (vinylbenzyl) aminoethyl) -N-gamma- (N-vinylbenzyl) -gamma-aminopropyltrimethoxysilane, methylbenzylaminopropyltrimethoxysilane, methylaminoethylaminoethyl) phenyltrimethoxysilane, N-beta- (N-di (vinylbenzyl) aminoethyl) -N-gamma-aminopropyltrimethoxysilane, N-gamma- (N-vinylbenzyl) -gamma-aminopropyltrimethoxysilane, and methylbenzylaminopropyltrimethoxysilane, dimethylaminoethylaminopropyltrimethoxysilane, benzylaminoethylaminopropyltrimethoxysilane, benzylaminoethylaminopropyltriethoxysilane, 3-ureidopropyltriethoxysilane, 3- (N-phenyl) aminopropyltrimethoxysilane, N-bis [3- (trimethoxysilyl) propyl ] ethylenediamine, (aminoethylaminoethyl) phenethyltrimethoxysilane, (aminoethylaminoethyl) phenethyltriethoxysilane, (aminoethylaminoethyl) phenethyltripropoxysilane, (aminoethylaminoethyl) phenethyltriisopropoxysilane, (aminoethylaminomethyl) phenethyltrimethoxysilane, (aminoethylaminomethyl) phenethyltriethoxysilane, (aminoethylaminomethyl) phenethyltripropoxysilane, (aminoethylaminomethyl) phenethyltriisopropoxysilane, N- [2- [3- (trimethoxysilyl) propylamino ] ethyl ] ethylenediamine, N- [2- [3- (triethoxysilyl) propylamino ] ethyl ] ethylenediamine, N- [2- [3- (tripropoxysilyl) propylamino ] ethyl ] ethylenediamine, and the like.
More preferably, as shown in fig. 2 (b), the light-emitting particles 90 in which the surface of the light-emitting particles 91 contained in the hollow particles is provided with a polymer layer 92 made of a hydrophobic polymer (hereinafter, may be referred to as "polymer-coated light-emitting particles 90"). The polymer-coated light-emitting particles 90 having the polymer layer 92 can further improve stability against heat and oxygen and can obtain excellent particle dispersibility, and thus can obtain more excellent light-emitting characteristics when formed into a light-converting layer.
1-1-2 silica-coated luminescent particles
Fig. 3 (a) and 3 (b) show another embodiment of the semiconductor nanocrystal-containing nanoparticle of the present invention. The light-emitting particle 91 shown in fig. 3 (a) (hereinafter, also referred to as "silica-coated light-emitting particle 91") includes: a semiconductor nanocrystal (hereinafter, also referred to simply as "nanocrystal 911") made of a metal halide and having a light-emitting property, and a surface layer 914 made of a ligand coordinated to the surface of the nanocrystal 911 and having siloxane bonds formed between molecules serving as a silane compound in the ligand. The luminescent particles 91 may for example be obtained by: a precursor of the nanocrystal 911, a ligand such as oleic acid or oleylamine, and a ligand having a site capable of siloxane bonding are mixed, and the ligand is coordinated to the surface of the nanocrystal 911 while the nanocrystal 911 is precipitated, and then siloxane bonds are continuously generated. Since the nanocrystals 911 are protected by the silica surface layer 914, the luminescent particles 91 have excellent stability against heat and oxygen, and as a result, have excellent luminescent characteristics.
More preferably, as shown in fig. 3 b, the light-emitting particles 90 (hereinafter, sometimes referred to as "polymer-coated light-emitting particles 90") are provided with a polymer layer 92 made of a hydrophobic polymer on the surface of the silica-coated light-emitting particles 91 as shown in the silica-coated light-emitting particles 91 b. The polymer-coated light-emitting particles 90 having the polymer layer 92 can further improve stability against heat and oxygen and can obtain excellent particle dispersibility, and thus can obtain more excellent light-emitting characteristics when formed into a light-converting layer.
The silica-coated light-emitting particle 91 shown in fig. 3 (a) has: the light-emitting material includes the nanocrystal 911 having a light-emitting property, and a surface layer 914 that is composed of a ligand coordinated to the surface of the nanocrystal 911 and in which molecules serving as a silane compound form a siloxane bond with each other. Therefore, the silica-coated light-emitting particle 91 can maintain excellent light-emitting characteristics because the nanocrystal 911 is protected by the surface layer 914.
The silica-coated light-emitting particle 91 can be produced by the following method: the particles 91 having a surface layer having siloxane bonds formed on the surface of the semiconductor nanocrystal are obtained by mixing a solution containing a raw material compound of the semiconductor nanocrystal and a solution containing "an aliphatic amine containing an aliphatic carboxylic acid and a compound having a reactive group that contains Si and can form a siloxane bond" to precipitate a luminescent perovskite-type semiconductor nanocrystal and to position the compound on the surface of the semiconductor nanocrystal, and then condensing the reactive group in the coordinated compound.
The silica-coated light-emitting particle 91 itself can be used alone as a light-emitting particle.
< surface layer 914 >
The surface layer 914 is composed of a ligand containing a compound that can coordinate to the surface of the nanocrystal 911 and whose molecules can form siloxane bonds with each other.
The ligand is a compound having a bonding group that bonds with the cation included in the nanocrystal 911, including a compound having a reactive group that contains Si and forms a siloxane bond. The bonding group is preferably at least 1 kind of a carboxyl group, a carboxylic anhydride group, an amino group, an ammonium group, a mercapto group, a phosphino group, a phosphinoxide group, a phosphate group, a phosphonate group, a phosphinate group, a sulfonate group, and a borate group, and more preferably at least 1 kind of a carboxyl group and an amino group. Examples of such ligands include compounds containing a carboxyl group or an amino group, and 1 or more of these may be used alone or in combination.
Examples of the carboxyl group-containing compound include: a linear or branched aliphatic carboxylic acid having 1 to 30 carbon atoms. Specific examples of such a carboxyl group-containing compound include: arachidonic acid, crotonic acid, trans-2-decenoic acid, erucic acid, 3-decenoic acid, cis-4, 7,10,13,16, 19-docosahexaenoic acid, 4-decenoic acid, all-cis-5, 8,11,14, 17-eicosapentaenoic acid, all-cis-8, 11, 14-eicosatrienoic acid, cis-9-hexadecenoic acid, trans-3-hexenoic acid, trans-2-hexenoic acid, 2-heptenoic acid, 3-heptenoic acid, 2-hexadecenoic acid, linolenic acid, linoleic acid, gamma-linolenic acid, 3-nonenoic acid, 2-nonenoic acid, trans-2-octenoic acid, petroselic acid, elaidic acid, oleic acid, 3-octenoic acid, trans-2-pentenoic acid trans-3-pentenoic acid, ricinoleic acid, sorbic acid, 2-tridecenoic acid, cis-15-tetracosenoic acid, 10-undecenoic acid, 2-undecenoic acid, acetic acid, butyric acid, behenic acid, cerotic acid, capric acid, eicosanoic acid, heneicosic acid, heptadecanoic acid, heptanoic acid, caproic acid, heptacosanoic acid, lauric acid, myristic acid, melissic acid, octacosanoic acid, nonadecanoic acid, nonacosanoic acid, n-caprylic acid, palmitic acid, pentadecanoic acid, propionic acid, pentacosanoic acid, pelargonic acid, stearic acid, tetracosanoic acid, tricosanoic acid, tridecanoic acid, undecanoic acid, valeric acid, and the like.
Examples of the amino group-containing compound include: a linear or branched aliphatic amine having 1 to 30 carbon atoms. Specific examples of such amino group-containing compounds include: 1-aminoheptadecane, 1-aminononadecane, heptadecan-9-amine, stearylamine, oleylamine, 2-n-octyl-1-dodecylamine, allylamine, pentylamine, 2-ethoxyethylamine, 3-ethoxypropylamine, isobutylamine, isopentylamine, 3-methoxypropylamine, 2-methoxyethylamine, 2-methylbutylamine, neopentylamine, propylamine, methylamine, ethylamine, butylamine, hexylamine, heptylamine, n-octylamine, 1-aminodecane, nonanamine, 1-aminoundecane, dodecylamine, 1-aminopentadecane, 1-aminotridecane, hexadecylamine, tetradecylamine and the like.
In addition, the compound having a reactive group containing Si and forming a siloxane bond preferably has a bonding group to be bonded to a cation included in the nanocrystal 911.
The reactive group is preferably a hydrolyzable silyl group such as a silanol group or an alkoxysilyl group having 1 to 6 carbon atoms, in view of easy formation of a siloxane bond.
Examples of the bondable group include a carboxyl group, an amino group, an ammonium group, a mercapto group, a phosphino group, a phosphate group, a phosphonate group, a phosphinate group, a sulfonate group, and a borate group. Among them, the bonding group is preferably at least 1 kind of a carboxyl group, a mercapto group, and an amino group. These bonding groups have a higher affinity for the cations contained in the nanocrystal 911 than the reactive groups described above. Therefore, the ligand coordinates the bonding group to the nanocrystal 911 side, and the surface layer 914 can be formed more easily and reliably.
The compound having a reactive group containing Si and forming a siloxane bond may contain 1 or more kinds of silicon compounds containing a bonding group, or 2 or more kinds of silicon compounds used in combination.
Preferably, the silicon compound may contain any of a carboxyl group-containing silicon compound, an amino group-containing silicon compound, and a mercapto group-containing silicon compound, or 2 or more kinds thereof may be used in combination.
Specific examples of the carboxyl group-containing silicon compound include: 3- (trimethoxysilyl) propionic acid, 3- (triethoxysilyl) propionic acid, 2-carboxyethylphenylbis (2-methoxyethoxy) silane, N- [3- (trimethoxysilyl) propyl ] -N ' -carboxymethylethylenediamine, N- [3- (trimethoxysilyl) propyl ] phthalic acid amide, N- [3- (trimethoxysilyl) propyl ] ethylenediamine-N, N ', N ' -triacetic acid, and the like.
On the other hand, specific examples of the amino group-containing silicon compound include: 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldiethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldipropaxysilane, N- (2-aminoethyl) -3-aminopropylmethyldiisopropyloxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltripropoxysilane, N- (2-aminoethyl) -3-aminopropyltriisopropoxysilane, N- (2-aminoethyl) -3-aminoisobutyldimethylmethoxysilane, N- (2-aminoethyl) -3-aminoisobutylmethyldimethoxysilane, N- (2-aminoethyl) -11-aminoundecyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylsilanetriol, 3-triethoxysilyl-N- (1, 3-dimethylbutylidene), N-aminopropylpropylaminopropyltriol-3-aminopropyltrimethoxysilane, N, the content of the first and second polymers, N-bis [3- (trimethoxysilyl) propyl ] ethylenediamine, (aminoethyl) phenyltrimethoxysilane, (aminoethyl) phenyltriethoxysilane, (aminoethyl) phenyltripropoxysilane, (aminoethyl) phenyltriisopropoxysilane, (aminoethyl aminomethyl) phenyltrimethoxysilane, (aminoethyl aminomethyl) phenyltriethoxysilane, (aminoethyl aminomethyl) phenyltripropoxysilane, (aminoethyl aminomethyl) phenyltriisopropoxysilane, N- (vinylbenzyl) -2-aminoethyl-3-aminopropyltrimethoxysilane, N- (vinylbenzyl) -2-aminoethyl-3-aminopropylmethyldimethoxysilane, N-beta- (N-vinylbenzylaminoethyl) -N-gamma- (N-vinylbenzyl) -gamma-aminopropyltrimethoxysilane, N-beta- (N-di (vinylbenzyl) aminoethyl) -N-gamma- (N-vinylbenzyl) -gamma-aminopropyltrimethoxysilane, methylbenzylaminopropyltrimethoxysilane, N-beta- (N-di (vinylbenzyl) aminoethyl) -N-gamma- (N-vinylbenzyl) gamma-aminopropyltrimethoxysilane, dimethylaminoethylaminopropyltrimethoxysilane, benzylaminoethylaminopropyltrimethoxysilane, benzylaminoethylaminopropyltriethoxysilane, 3-ureidopropyltriethoxysilane, 3- (N-phenyl) aminopropyltrimethoxysilane, N-bis [3- (trimethoxysilyl) propyl ] ethylenediamine, (aminoethyl) phenethyltrimethoxysilane, (aminoethyl) phenethyltriethoxysilane, (aminoethyl) phenethyltripropoxysilane, (aminoethyl) phenethyl triisopropoxysilane, (aminoethyl) phenethyl-trimethoxysilane, (aminoethyl) phenethyl-triethoxysilane, (aminoethyl) phenethyltripropoxysilane, (N- [2- [3- (trimethoxysilyl) propylamino ] ethyl ] ethylenediamine, N- [2- [3- (triethoxysilyl) propylamino ] ethyl ] ethylenediamine, N- [2- [3- (tripropoxysilyl) propylamino ] ethyl ] ethylenediamine, and the like.
Specific examples of the mercapto group-containing silicon compound include: 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 2-mercaptoethylmethyldimethoxysilane, 2-mercaptoethylmethyldiethoxysilane, 3- [ ethoxybis (3, 6,9,12, 15-pentaoxaoctacosan-1-yloxy) silyl ] -1-propanethiol and the like.
In the silica-coated luminescent particle 91 shown in fig. 3 (a), oleic acid, oleylamine, and 3-aminopropyltrimethoxysilane as ligands are coordinated to the surface of the nanocrystal 911 including a Pb cation as an M site, and the 3-aminopropyltrimethoxysilane is further reacted to form the surface layer 914.
The thickness of the surface layer 914 is preferably 0.5 to 50nm, more preferably 1.0 to 30nm. The luminescent particles 91 having the surface layer 914 with such a thickness can sufficiently improve the stability of the nanocrystals 911 against heat.
The thickness of the surface layer 914 can be changed by adjusting the number of atoms (chain length) of a bonding group that bonds a ligand and the number of atoms of a bonding structure that bonds a reactive group.
< method for producing silica-coated light-emitting particle 91 >
Such silica-coated light-emitting particles 91 can be easily produced by: after mixing a solution of a raw material compound containing the nanocrystal 911 with a solution of "a compound having a bonding group capable of bonding to a cation contained in the nanocrystal 911 and a compound having a reactive group containing Si and capable of forming a siloxane bond", the reactive group in the compound having a reactive group containing Si and capable of forming a siloxane bond, which is provided on the surface of the deposited nanocrystal 911, is condensed. In this case, there are a method of manufacturing by heating and a method of manufacturing without heating.
First, a method of heating to produce the silica-coated light-emitting particles 91 will be described. 2 solutions containing the raw material compounds for synthesizing semiconductor nanocrystals by reaction were prepared separately. At this time, a compound having a bonding group to be bonded to the cation included in the nanocrystal 911 is previously added to one of the 2 solutions, and a compound having a reactive group containing Si and capable of forming a siloxane bond is previously added to the other solution. Then, they are mixed under an inert gas atmosphere and reacted at a temperature of 140 to 260 ℃. Next, a method of precipitating the nanocrystals by cooling to-20 to 30 ℃ and stirring is exemplified. The deposited nanocrystals become nanocrystals in which a surface layer 914 having siloxane bonds is formed on the surface of the nanocrystals 911, and can be obtained by a conventional method such as centrifugation.
Specifically, for example, a solution containing cesium carbonate, oleic acid, and an organic solvent is prepared. As the organic solvent, 1-octadecene, dioctyl ether, diphenyl ether and the like can be used. In this case, the addition amounts of cesium carbonate and oleic acid are preferably adjusted so that the amount of cesium carbonate and oleic acid is 0.2 to 2g and 0.1 to 10mL, respectively, based on 40mL of the organic solvent. Drying the obtained solution at 90-150 ℃ for 10-180 minutes under reduced pressure, and heating to 100-200 ℃ under the atmosphere of inert gas such as argon, nitrogen and the like to obtain the cesium-oleic acid solution.
On the other hand, a solution containing lead (II) bromide and the same organic solvent as described above was prepared. At this time, 20 to 100mg of lead (II) bromide was added to 5mL of the organic solvent. The obtained solution is dried under reduced pressure at 90 to 150 ℃ for 10 to 180 minutes, and then 0.1 to 2mL of 3-aminopropyltriethoxysilane is added under an inert gas atmosphere such as argon or nitrogen.
Then, the cesium-oleic acid solution was added in a state where the solution containing lead (II) bromide and 3-aminopropyltriethoxysilane was heated to 140 to 260 ℃, heated and stirred for 1 to 10 seconds to react, and then the obtained reaction solution was cooled with an ice bath. In this case, 0.1 to 1mL of a cesium-oleic acid solution is preferably added to 5mL of a solution containing lead (II) bromide and 3-aminopropyltriethoxysilane. In the process of stirring at the temperature of between 20 ℃ below zero and 30 ℃, the nanocrystal 911 is separated out, and the 3-aminopropyltriethoxysilane and the oleic acid are coordinated on the surface of the nanocrystal 911.
Then, the obtained reaction solution is stirred at room temperature (10 to 30 ℃ C., humidity 5 to 60%) for 5 to 300 minutes under the air, and then 0.1 to 50mL of ethanol is added to obtain a suspension. The alkoxysilyl group of 3-aminopropyltriethoxysilane condensed during stirring at room temperature under the atmosphere, and a surface layer 914 having siloxane bonds was formed on the surface of the nanocrystal 911.
By recovering the solid matter by centrifugal separation of the obtained suspension and adding the solid matter to hexane, a light-emitting particle dispersion liquid can be obtained in which silica-coated light-emitting particles 91 having a surface layer 914 having siloxane bonds on the surface of a nanocrystal 911 made of cesium lead tribromide are dispersed in toluene.
Further, by adding the above-mentioned recovered solid matter to isobornyl methacrylate, which is a photopolymerizable compound, described below, a light-emitting particle dispersion liquid can be obtained in which the silica-coated light-emitting particles 91 having the surface layer 914 having a siloxane bond on the surface of the nanocrystal 911 made of a lead methylammonium tribromide crystal are dispersed in isobornyl methacrylate.
Next, a method for producing the silica-coated light-emitting particles 91 without heating will be described. The following methods may be mentioned: a solution of a raw material compound containing semiconductor nanocrystals and a compound having a bonding group that bonds to a cation contained in the nanocrystal 911 (excluding a compound having a reactive group that contains Si and can form a siloxane bond) was added dropwise to a solution in which a compound having a reactive group that contains Si and can form a siloxane bond was dissolved in an organic solvent that is a poor solvent for nanocrystals, and mixed, thereby precipitating nanocrystals. The amount of the organic solvent used is preferably 10 to 1000 times the amount of the semiconductor nanocrystal by mass. The deposited nanocrystals become nanocrystals in which a surface layer 914 having siloxane bonds is formed on the surface of the nanocrystal 911, and can be obtained by a conventional method such as centrifugation.
Specifically, as a solution of a raw material compound containing semiconductor nanocrystals, for example, a solution containing lead (II) bromide, cesium bromide, oleic acid, oleylamine, and an organic solvent is prepared. The organic solvent is only required to be a good solvent for the nanocrystal, and dimethyl sulfoxide, N-dimethylformamide, N-methylformamide, and a mixed solvent thereof are preferable from the viewpoint of compatibility. In this case, the addition amount of each of lead (II) bromide, cesium bromide, oleic acid and oleylamine is preferably adjusted to 10 to 50mg, 5 to 25mg, 0.2 to 2mL and 0.05 to 0.5mL, respectively, relative to 10mL of the organic solvent.
On the other hand, as a solution containing a compound having a reactive group containing Si and capable of forming a siloxane bond and an organic solvent which is a poor solvent for the nanocrystal, for example, 3-aminopropyltriethoxysilane and a poor solvent are prepared. As the poor solvent, isopropyl alcohol, toluene, hexane, or the like can be used. In this case, the amount of each of the 3-aminopropyltriethoxysilane compounds added is preferably adjusted to 5mL or 0.01 to 0.5mL of the poor solvent.
Then, 0.1 to 1mL of a solution containing the lead (II) bromide, cesium bromide, oleic acid and oleylamine was added to 5mL of a solution containing the 3-aminopropyltriethoxysilane and the poor solvent at 0 to 30 ℃ under the atmospheric air, and immediately stirred for 5 to 180 seconds under the atmospheric air, and then the solid matter was collected by centrifugal separation. When the mixture is added to a poor solvent, the nanocrystal 911 is precipitated, and 3-aminopropyltriethoxysilane, oleic acid, and oleylamine are coordinated on the surface of the crystal 911. Then, the alkoxysilyl group of 3-aminopropyltriethoxysilane condenses during stirring under the atmosphere, thereby forming a surface layer 914 having siloxane bonds on the surface of the nanocrystal 911.
By adding the recovered solid matter to toluene, a light-emitting particle dispersion liquid in which silica-coated light-emitting particles 91 having a surface layer 914 having siloxane bonds on the surface of nanocrystals 911 composed of cesium lead tribromide crystals are dispersed in toluene can be obtained.
Further, by adding the recovered solid material to isobornyl methacrylate described below as a photopolymerizable compound, a light-emitting particle dispersion in which isobornyl methacrylate is dispersed in silica-coated light-emitting particles 91 having a surface layer 914 having siloxane bonds on the surface of nanocrystals 911 composed of cesium lead tribromide crystals can also be obtained.
1-1-3. Titanium-coated luminescent particles
As another mode of the nanoparticle including a semiconductor nanocrystal in the present invention, the semiconductor nanocrystal may be coated with titanium oxide. When the titanium oxide coating is used, the titanium oxide coating can be obtained by the following steps: in a solution in which semiconductor nanocrystals are dispersed in a hydrophobic solvent, an appropriate amount of titanium alkoxide is added and stirred in an inert atmosphere containing no water and oxygen. By coating the surface of the semiconductor nanocrystal with titanium oxide, the surface defects of the crystal can be compensated for, and the reduction in emission characteristics can be suppressed. As the titanium oxide, for example, a hydrolysate of titanium alkoxide having (R-O) 3 Titanium oxide having a structure of Ti-O- (R's each independently represents a linear or branched alkyl group having 1 to 8 carbon atoms).
Such a titanium-coated light-emitting particle can be formed by the following method.
First, the nanocrystals are dispersed in a hydrophobic organic solvent. The hydrophobic organic solvent is not particularly limited, but toluene, chloroform, hexane and cyclohexane are preferable, and toluene and cyclohexane are more preferable. These hydrophobic organic solvents may be used alone or in combination of 2 or more. Subsequently, titanium alkoxide is added to the nanocrystal dispersion solution and stirred to coordinate to the nanocrystal surface and react therewith, thereby coating the crystal surface.
When a tetravalent titanium alkoxide is used as the titanium alkoxide, 1 alkoxy group in the titanium alkoxide is partially hydrolyzed by a slight amount of water contained in the solvent to produce (R-O) 3 -Ti-O-. As titanium alkoxides, preference is given to titanium alkoxides of the formula Ti (OR) 4 The compound represented. In the formula, R independently represents methyl, ethyl, isopropyl, 2-ethylhexyl.
Specific examples of such titanium alkoxides include: titanium isopropoxide, titanium methoxide, tetraethyl orthotitanate, titanium 2-ethylhexyloxide, titanium diisopropoxide bis (acetylacetonate), and the like. These titanium alkoxides may be used alone or in an amount of 2 or more, and when 2 or more titanium alkoxides are used, it is preferable to coat the nanocrystal surface by controlling the amount and timing of addition in consideration of the respective reaction rates.
Further, after the surface layer is formed on the nanocrystal surface, the surface layer may be further coated with a layer of a polymer containing a compound C having a hydrolyzable silyl group.
Further, after the surface layer is formed on the nanocrystal surface, the surface layer may be further coated with a layer of a polymer comprising a polymer B having a first structural unit having a basic group and a second structural unit having no basic group and being solvent-philic, and a compound C having a hydrolyzable silyl group.
The polymer B is an amphiphilic compound and is a polymer having a first constitutional unit having a basic group and a second constitutional unit having no basic group and being solvent-philic and having excellent affinity for a dispersion medium. The dispersion medium referred to herein is a dispersion medium in a dispersion containing silica-coated light-emitting particles, and may be a resin such as an organic solvent or a photopolymerizable compound.
The polymer B more preferably has: a first structural unit having a basic group represented by the following formula (B1), and a solvent-philic second structural unit represented by the following formula (B2).
Figure BDA0004092365490000251
(in the formula, R 1 And R 2 Each independently represents a hydrogen atom or a methyl group, R B1 Represents a basic 1-valent radical, R B2 A 1-valent group having an organic group and having excellent affinity for a dispersion medium,
R B1 represents a basic group containing a primary amino group, a secondary amino group, a tertiary amino group, a quaternary ammonium group, an imino group, a pyridyl group, a pyrimidyl group, a piperazinyl group, a piperidyl group, an imidazolyl group, a pyrrolidinyl group, and an imidazolidinyl groupThe base group is a group of a compound,
X 1 and X 2 Independently represent-COO-, -OCO-, an alkyl chain with 1-8 carbon atoms and a single bond,
R B2 represents a linear or branched alkyl group having 2 to 15 carbon atoms, a cycloalkyl group having 4 to 20 carbon atoms which may have a substituent, a polyoxyalkylene group having 10 to 50 carbon atoms and a terminal hydroxyl group or alkoxy group, or an aromatic group which may have a substituent).
In the polymer B, 1 type of each of the structural units represented by the formulae (B1) and (B2) may be used, or 2 or more types may be used in combination. Further, the polymer B is more preferably a block copolymer having a first structural unit represented by the formula (B1) as a first polymer block and a second structural unit represented by the formula (B2) as a second polymer block.
The content of the first structural unit in the polymer B is, for example, preferably 5 mol% or more, 7 mol% or more, or 10 mol% or more, and preferably 50 mol% or less, 30 mol% or less, or 20 mol% or less, based on the entire structural units constituting the polymer B.
The content of the second structural unit in the polymer B is, for example, preferably 70 mol% or more, 75 mol% or more, or 80 mol% or more, and preferably 95 mol% or less, 93 mol% or less, or 90 mol% or less based on the entire structural units constituting the polymer B.
The polymer B may include other structural units in addition to the first structural unit and the second structural unit. In this case, the total content of the first constitutional unit and the second constitutional unit in the polymer B is preferably 70 mol% or more, 80 mol% or more, or 90 mol% or more, for example, based on the total constitutional units constituting the polymer B.
The silane compound C has a hydrolyzable silyl group, and a siloxane bond is formed by condensation of the silyl group, so that a layer containing a polymer of the silane compound C is formed on the surface of the surface layer 914, and a light-emitting particle having a surface layer containing Si on the surface of the nanoparticle including the semiconductor nanocrystal is formed.
The silane compound C is preferably a compound represented by the following formula (C1), for example.
Figure BDA0004092365490000261
In the formula, R C1 And R C2 Each independently represents an alkyl group, R C3 And R C4 Each independently represents a hydrogen atom or an alkyl group, n represents 0 or 1, and m represents an integer of 1 or more. m is preferably an integer of 10 or less.
As the compound represented by the formula (C1), specific examples include: tetrabutoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, phenyltrimethoxysilane, vinyltriethoxysilane, n-propyltrimethoxysilane, isopropyltrimethoxysilane, n-butyltriethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane, n-dodecyltrimethoxysilane, n-dodecyltriethoxysilane, n-hexadecyltrimethoxysilane, n-hexadecyltriethoxysilane, n-octadecyltrimethoxysilane, trimethoxy- (3, 3-trifluoropropyl) silane, trimethoxy (pentafluorophenyl) silane, trimethoxy- (11-pentafluorophenoxyundecyl) silane, trimethoxy- (1H, 2H-nonafluorohexyl) silane, partially hydrolyzed oligomer of tetramethoxysilane (product name: sodium silicate 51, sodium silicate 53A (see above, manufactured by COCOAT Co., ltd.)), partial hydrolyzed oligomer of tetramethoxysilane (product name: co) and co-hydrolyzed oligomer (co) manufactured by CoAT Co., ltd.), and the above product (product name: methyl silicate 48, co-Methyl silane, co-Methyl methacrylate).
As the silane compound C, for example, a compound represented by the following formula (C2) and a compound represented by the following formula (C3) can be used in combination in addition to the compound represented by the above formula (C1).
Figure BDA0004092365490000271
In the formula, R C21 、R C22 、R C31 Each independently represents an alkyl group, R C23 、R C24 、R C32 、R C33 And R C34 Each independently represents a hydrogen atom, an alkyl group which may have a substituent, a phenyl group or a cyclohexyl group, the carbon atom in the alkyl group may be substituted with an oxygen atom or a nitrogen atom, and m2 represents an integer of 1 to 10.
Specific examples of the compound represented by the formula (C2) and the compound represented by the formula (C3) include dimethyldiethoxysilane, diphenyldimethoxysilane, methylethyldimethoxysilane, and trimethylmethoxysilane. The compound represented by the formula (C1) may be used alone in 1 kind, or may be used in combination in 2 or more kinds. The compound represented by the formula (C2) and the compound represented by the formula (C3) may be used in combination with the compound represented by the general formula (C1) in 1 or 2 or more species.
1-1-4 polymer-coated luminescent particles
The polymer-coated light-emitting particle 90 shown in fig. 1, 2 (b) and 3 (b) can be obtained by: the polymer layer 92 is formed by coating the surface of the mother particle 91 with a hydrophobic polymer, using the hollow particle-encapsulated light-emitting particle 91 or the silica-coated light-emitting particle 91 obtained in the above step as a mother particle (hereinafter, these light-emitting particles 91 may be referred to as "mother particles 91"). Polymer-coated light-emitting particle 90 has polymer layer 92 having hydrophobicity, and thus can impart high stability to light-emitting particle 90 against oxygen and moisture, and further can improve dispersion stability of light-emitting particle 90.
< method for producing polymer-coated light-emitting particle >
Such a polymer layer 92 can be formed by the following method I, method II, or the like.
The method I comprises the following steps: the surface of the mother particle 91 is coated with the hydrophobic polymer by adding and mixing the mother particle 91 to the varnish containing the hydrophobic polymer.
Method II: the polymer can be formed by a method in which a polymer containing a polymerizable unsaturated group that is soluble in a nonaqueous solvent, and a polymerizable unsaturated monomer that is soluble in a nonaqueous solvent and becomes insoluble or poorly soluble after polymerization are supported on the surface of the mother particle 91, and then the polymer and the polymerizable unsaturated monomer are polymerized.
The hydrophobic polymer in the method I includes a polymer obtained by polymerizing a polymerizable unsaturated monomer with the polymer in the method II.
Of these, polymer layer 92 is preferably formed by method II. According to the method II, the polymer layer 92 having a uniform thickness and excellent adhesion to the mother particle 91 can be formed.
The method II for forming the polymer layer will be described in detail below.
[ non-aqueous solvent ]
The nonaqueous solvent is preferably an organic solvent in which the hydrophobic polymer is soluble, and is more preferably an organic solvent capable of uniformly dispersing the light-emitting particles 91. By using such a nonaqueous solvent, the hydrophobic polymer can be adsorbed to the light-emitting particles 91 very easily to coat the polymer layer 92. More preferably, the nonaqueous solvent is a low dielectric constant solvent. By using a low dielectric constant solvent, the hydrophobic polymer can be firmly adsorbed to the surface of the light-emitting particle 91 and the polymer layer can be coated by mixing the hydrophobic polymer and the light-emitting particle 91 in the nonaqueous solvent.
Even when the light-emitting particles 90 are washed with a solvent as described later, the polymer layer 92 obtained in the above manner is difficult to be removed from the light-emitting particles 91. Further, the lower the dielectric constant of the nonaqueous solvent is, the better. Specifically, the dielectric constant of the nonaqueous solvent is preferably 10 or less, more preferably 6 or less, and particularly preferably 5 or less. The preferable nonaqueous solvent is preferably an organic solvent containing at least one selected from the group consisting of an aliphatic hydrocarbon solvent, an alicyclic hydrocarbon solvent, and an aromatic hydrocarbon solvent.
Examples of the aliphatic hydrocarbon solvent include: n-hexane, n-heptane, n-octane, isohexane, etc., and examples of the alicyclic hydrocarbon solvent include: cyclopentane, cyclohexane, ethylcyclohexane, and the like, and aromatic hydrocarbon solvents include toluene, xylene, and the like.
In addition, a mixed solvent in which another organic solvent is mixed with at least one selected from the group consisting of an aliphatic hydrocarbon solvent, an alicyclic hydrocarbon solvent, and an aromatic hydrocarbon solvent may be used as the nonaqueous solvent within a range not to impair the effects of the present invention. Examples of the other organic solvents include: ester-based solvents such as methyl acetate, ethyl acetate, n-butyl acetate, and amyl acetate; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone and cyclohexanone; and alcohol solvents such as methanol, ethanol, n-propanol, isopropanol, and n-butanol.
When used as the mixed solvent, the amount of at least one selected from the group consisting of an aliphatic hydrocarbon solvent, an alicyclic hydrocarbon solvent, and an aromatic hydrocarbon solvent is preferably 50 mass% or more, and more preferably 60 mass% or more.
[ Polymer having polymerizable unsaturated group soluble in nonaqueous solvent ]
The polymerizable unsaturated group-containing polymer (hereinafter also referred to as "polymer (P)") soluble in a nonaqueous solvent used in the present step includes: a polymer obtained by introducing a polymerizable unsaturated group into a copolymer containing, as monomer components, (A1) an alkyl (meth) acrylate having an alkyl group having 4 or more carbon atoms, (A2) a (meth) acrylate having a polymerizable functional group at the end, (B, C) a fluorine-containing compound having a polymerizable unsaturated group, or (D) a silicon-containing compound having a polymerizable unsaturated group; or a macromonomer comprising a copolymer of an alkyl (meth) acrylate (A1) having an alkyl group having 4 or more carbon atoms, a (meth) acrylate (A2) having a polymerizable functional group at the end, a monomer having a polymerizable unsaturated group containing a fluorine-containing compound (B, C) as the main component, or a monomer having a polymerizable unsaturated group containing a silicon-containing compound (D) as the main component.
Examples of the alkyl (meth) acrylate (A1) include: n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate.
Examples of the (meth) acrylate (A2) having a polymerizable functional group at the end include: dimethyl urethane (meth) acrylate, diethyl urethane (meth) acrylate; diester compounds of unsaturated dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid and monohydric alcohols. In the present specification, "(meth) acrylate" means both methacrylate and acrylate. The same applies to the expression "(meth) acryloyl".
Examples of the fluorine-containing compound (B) having a polymerizable unsaturated group include compounds represented by the following general formula (B1).
Figure BDA0004092365490000291
In the above general formula (B1), R 4 Is a hydrogen atom, a fluorine atom, a methyl group, a cyano group, a phenyl group, a benzyl group or-C n H 2n -Rf a (wherein n is an integer of 1 to 8, rf a Is a group represented by any one of the following formulae (Rf-1) to (Rf-7).
In the general formula (B1), L is a group represented by any of the following formulas (L-1) to (L-10).
Figure BDA0004092365490000301
N in the above formulae (L-1), (L-3), (L-5), (L-6) and (L-7) is an integer of 1 to 8. In the above formulae (L-8), (L-9) and (L-10), m is an integer of 1 to 8, and n is an integer of 0 to 8. Rf in the above formulae (L-6) and (L-7) b Are represented by the following formulae (Rf-1) to (1)Rf-7).
In the general formula (B1), rf is a group represented by any of the following formulas (Rf-1) to (Rf-7).
——C n F 2n+1 (Rf-1)
——C n F 2n H (Rf-2)
——C n F 2n-1 (Rf-3)
——C n F 2n-3 (Rf-4)
——C m F 2m OC n F 2n CF 3 (Rf-5)
——C m F 2m OC n F 2n OC p F 2p CF 3 (Rf-6)
——CF 2 OC 2 F 4 OC 2 F 4 OCF 3 (Rf-7)
N in the above formulae (Rf-1) to (Rf-4) is an integer of 4 to 6. In the formula (Rf-5), m is an integer of 1 to 5, n is an integer of 0 to 4, and the total of m and n is 4 to 5. In the formula (Rf-6), m is an integer of 0 to 4, n is an integer of 1 to 4, p is an integer of 0 to 4, and the total of m, n, and p is 4 to 5.
Further, preferable specific examples of the compound represented by the general formula (B1) include: methacrylates represented by the following formulae (B1-1) to (B1-7), acrylates represented by the following formulae (B1-8) to (B1-15), and the like. These compounds may be used alone in 1 kind, or in combination of 2 or more kinds.
Figure BDA0004092365490000311
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Figure BDA0004092365490000321
Examples of the fluorine-containing compound (C) having a polymerizable unsaturated group include compounds having a poly (perfluoroalkylene ether) chain and polymerizable unsaturated groups at both ends thereof.
The poly (perfluoroalkylene ether) chain preferably has a structure in which 2-valent carbon fluorides having 1 to 3 carbon atoms are alternately linked to oxygen atoms.
The poly (perfluoroalkylene ether) chain may contain only 1 carbon atom number of 1-3 of 2-valent carbon fluoride groups, or may contain a plurality of such carbon atoms. Specific examples of the poly (perfluoroalkylene ether) include a structure represented by the following general formula (C1).
Figure BDA0004092365490000322
In the general formula (C1), X is the following formulas (C1-1) to (C1-5). The plurality of xs may be the same or different. In the case where different X are contained (in the case where plural kinds of repeating units X-O are contained), plural kinds of the same repeating units X-O may be present in a random state or a block state. N is the number of repeating units and is an integer of 1 or more.
——CF 2 —— (C1-1)
——CF 2 CF 2 —— (C1-2)
-CF 2 CF 2 CF 2 -(C1-3)
Figure BDA0004092365490000331
Among them, the poly (perfluoroalkylene ether) chain is preferably a structure in which a perfluoromethylene group represented by the formula (C1-1) and a perfluoroethylene group represented by the formula (C1-2) coexist, because the balance between the number of fluorine atoms and the number of oxygen atoms is good and the polymer (P) is likely to be entangled with the surface of the mother particle 91.
In this case, the ratio of the perfluoromethylene group represented by the formula (C1-1) to the perfluoroethylene group represented by the formula (C1-2) is preferably 1/10 to 10/1, more preferably 2/8 to 8/2, and still more preferably 3/7 to 7/3 in terms of a molar ratio [ perfluoromethylene (C1-1)/perfluoroethylene (C1-2) ].
In addition, n in the general formula (C1) is preferably 3 to 100, more preferably 6 to 70. Further, the total number of fluorine atoms contained in the poly (perfluoroalkylene ether) chain is preferably 18 to 200, more preferably 25 to 150. In the poly (perfluoroalkylene ether) chain having such a structure, the balance between the number of fluorine atoms and the number of oxygen atoms is further improved.
Examples of the raw material compound having a poly (perfluoroalkylene ether) chain before introduction of a polymerizable unsaturated group at both ends include the following formulas (C2-1) to (C2-6). In the following formulae (C2-1) to (C2-6), -PFPE- "is a poly (perfluoroalkylene ether) chain.
HO-CH 2 -PFPE-CH 2 -OH (C2-1)
HO-CH 2 CH 2 -PFPE-CH 2 CH 2 -OH (C2-2)
Figure BDA0004092365490000341
OCN-PFPE-NCO (C2-5)
Figure BDA0004092365490000342
Examples of the polymerizable unsaturated groups introduced into both ends of the poly (perfluoroalkylene ether) chain include structures represented by the following formulae (U-1) to (U-5).
Figure BDA0004092365490000343
Among them, from the viewpoint of the availability and the production easiness of the fluorine-containing compound (C) itself or the easiness of copolymerization with other monomers having a polymerizable unsaturated group, the acryloyloxy group represented by the above formula U-1 or the methacryloyloxy group represented by the above formula U-2 is preferable.
Specific examples of the fluorine-containing compound (C) include compounds represented by the following formulas (C-1) to (C-13). In the following formulae (C-1) to (C-13), -PFPE- "is a poly (perfluoroalkylene ether) chain.
Figure BDA0004092365490000351
Among these, the fluorine-containing compound (C) is preferably a compound represented by the above formula (C-1), (C-2), (C-5) or (C-6) from the viewpoint of ease of industrial production, and more preferably a compound having acryloyl groups at both ends of the poly (perfluoroalkylene ether) chain represented by the above formula (C-1) or a compound having methacryloyl groups at both ends of the poly (perfluoroalkylene ether) chain represented by the above formula (C-2) from the viewpoint of synthesis of the polymer (P) which is likely to be entangled with the surface of the mother particle 91.
Examples of the silicon-containing compound (D) having a polymerizable unsaturated group include compounds represented by the following general formula (D1).
Figure BDA0004092365490000361
In the general formula (D1), P is a polymerizable functional group, X a Is SiR 11 R 22 And Rd is a hydrogen atom, fluorine atom, methyl group, acryloyl group or methacryloyl group (wherein, R is 11 、R 22 Is methyl, or Si (CH) 3 ) An amino group, a glycidyl group, m is an integer of 0 to 100, and n is an integer of 0 to 4).
Specific examples of the silicon-containing compound (D) include compounds represented by the following formulae (D-1) to (D-13).
Figure BDA0004092365490000362
Examples of compounds other than the alkyl (meth) acrylate (A1), the (meth) acrylate compound (A2) having a polymerizable functional group at the end, the fluorine-containing compounds (B, C), and the silicon-containing compound (D) that can be used as the monomer having a polymerizable unsaturated group include: aromatic vinyl compounds such as styrene, α -methylstyrene, p-t-butylstyrene and vinyltoluene; and (meth) acrylate compounds such as benzyl (meth) acrylate, propyl dibromo (meth) acrylate, and phenyl tribromide (meth) acrylate.
These compounds are preferably used as random copolymers with the alkyl (meth) acrylate (A1), the (meth) acrylate (A2) having a polymerizable functional group at the end, the fluorine-containing compounds (B, C), or the silicon-containing compound (D). This can sufficiently improve the solubility of the obtained polymer (P) in a nonaqueous solvent.
The compounds that can be used as the monomer having a polymerizable unsaturated group may be used alone in 1 kind, or may be used in combination in 2 or more kinds. Among them, alkyl (meth) acrylates (A1) having a linear or branched alkyl group having 4 to 12 carbon atoms such as n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and lauryl methacrylate are preferably used.
The copolymer of the monomer having a polymerizable unsaturated group can be obtained by polymerizing the monomer having a polymerizable unsaturated group by a conventional method.
Further, the polymer (P) can be obtained by introducing a polymerizable unsaturated group into the copolymer.
Examples of the method for introducing the polymerizable unsaturated group include the following methods III to VI.
Method III is the following: a polymerizable monomer having a carboxylic acid group such as acrylic acid or methacrylic acid, and a polymerizable monomer having an amino group such as dimethylaminoethyl methacrylate or dimethylaminopropyl acrylamide are blended in advance as copolymerization components and copolymerized to obtain a copolymer having a carboxylic acid group or an amino group, and then the carboxylic acid group or the amino group is reacted with a monomer having a glycidyl group and a polymerizable unsaturated group such as glycidyl methacrylate.
Method IV is the following: a monomer having a hydroxyl group such as 2-hydroxyethyl methacrylate or 2-hydroxyethyl acrylate is blended in advance as a copolymerization component and copolymerized to obtain a copolymer having a hydroxyl group, and then the hydroxyl group is reacted with a monomer having an isocyanate group and a polymerizable unsaturated group such as ethyl isocyanate methacrylate.
Method V is the following method: in the polymerization, a carboxyl group is introduced into the terminal of the copolymer using thioglycolic acid as a chain transfer agent, and the carboxyl group is reacted with a monomer having a glycidyl group and a polymerizable unsaturated group such as glycidyl methacrylate.
Method VI is the following: the carboxyl group is introduced into the copolymer using a carboxyl group-containing azo initiator such as azobiscyanovaleric acid as a polymerization initiator, and the carboxyl group is reacted with a monomer having a glycidyl group and a polymerizable unsaturated group such as glycidyl methacrylate.
Among them, method III is most convenient and preferred.
[ polymerizable unsaturated monomer soluble in a nonaqueous solvent and rendered insoluble or poorly soluble after polymerization ]
Examples of the polymerizable unsaturated monomer (hereinafter, also referred to as "monomer (M)") which is soluble in the nonaqueous solvent and becomes insoluble or poorly soluble after polymerization include: vinyl monomers having no reactive polar group (functional group), vinyl monomers containing an amide bond, (meth) acryloyloxyalkyl phosphates, (meth) acryloyloxyalkyl phosphites, vinyl monomers containing a phosphorus atom, polymerizable unsaturated monomers containing a hydroxyl group, (meth) acrylic dialkylaminoalkyl esters, polymerizable unsaturated monomers containing an epoxy group, α, β -ethylenically unsaturated monomers containing an isocyanate group, polymerizable unsaturated monomers containing an alkoxysilyl group, α, β -ethylenically unsaturated monomers containing a carboxyl group, and the like.
Specific examples of the vinyl monomers having no reactive polar group include: (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and isopropyl (meth) acrylate; olefins such as (meth) acrylonitrile, vinyl acetate, vinyl chloride, vinylidene chloride, vinyl fluoride, and vinylidene fluoride.
Specific examples of the amide bond-containing vinyl monomers include: (meth) acrylamide, dimethyl (meth) acrylamide, N-t-butyl (meth) acrylamide, N-octyl (meth) acrylamide, diacetone acrylamide, dimethylaminopropyl acrylamide, alkoxylated N-methylolated (meth) acrylamides, and the like.
Specific examples of (meth) acryloyloxyalkyl phosphates include: dialkyl [ (meth) acryloyloxyalkyl ] phosphates, (meth) acryloyloxyalkyl acid phosphates, and the like.
Specific examples of (meth) acryloyloxyalkyl phosphites are, for example: dialkyl [ (meth) acryloyloxyalkyl ] phosphites, and (meth) acryloyloxyalkyl acid phosphites.
Specific examples of the phosphorus atom-containing vinyl monomers include: alkylene oxide adducts of the above (meth) acryloyloxyalkyl acid phosphates or (meth) acryloyloxyalkyl acid phosphites; ester compounds of epoxy group-containing vinyl monomers such as glycidyl (meth) acrylate and glycidyl methyl (meth) acrylate with phosphoric acid, phosphorous acid, or acid esters thereof; 3-chloro-2-acid phosphonoxypropyl (meth) acrylate, and the like.
Specific examples of the hydroxyl group-containing polymerizable unsaturated monomers include: hydroxyalkyl esters of polymerizable unsaturated carboxylic acids such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, di-2-hydroxyethyl fumarate, mono-2-hydroxyethyl monobutyl fumarate, polypropylene glycol mono (meth) acrylate, and polyethylene glycol mono (meth) acrylate, or adducts thereof with e-caprolactone; polymerizable unsaturated carboxylic acids such as unsaturated mono-or dicarboxylic acids and monoesters of dicarboxylic acids and monohydric alcohols, e.g., (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, and citraconic acid; monoglycidyl esters of monocarboxylic acids (e.g., glycidyl coconut oil fatty acid and glycidyl octanoate), butyl glycidyl ether, adducts of monoepoxides such as ethylene oxide and propylene oxide, or adducts of these compounds with epsilon-caprolactone, such as various unsaturated carboxylic acids and monoglycidyl esters of monocarboxylic acids (e.g., adducts of hydroxyalkyl esters of the polymerizable unsaturated carboxylic acids with polycarboxylic acid anhydrides (e.g., maleic acid, succinic acid, phthalic acid, hexahydrophthalic acid, tetrahydrophthalic acid, benzenetricarboxylic acid, benzenetetracarboxylic acid, "humic acid"), tetrachlorophthalic acid, and dodecynyl succinic acid); hydroxy vinyl ethers, and the like.
Specific examples of dialkylaminoalkyl (meth) acrylates include: dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, and the like.
Specific examples of the epoxy group-containing polymerizable unsaturated monomers include: epoxy group-containing polymerizable compounds, such as glycidyl (meth) acrylate, (β -methyl) glycidyl (meth) acrylate, and (meth) allyl glycidyl ether, which are obtained by addition reaction of various unsaturated carboxylic acids, such as polymerizable unsaturated carboxylic acids and equimolar adducts of hydroxyl group-containing vinyl monomers and the polycarboxylic acid anhydrides (e.g., mono-2- (meth) acryloyloxymethyl phthalate) and various polyepoxy compounds having at least 2 epoxy groups in 1 molecule, at equimolar ratios.
Specific examples of the isocyanate group-containing α, β -ethylenically unsaturated monomers include: an equimolar adduct of 2-hydroxyethyl (meth) acrylate and hexamethylene diisocyanate, a monomer having an isocyanate group and a vinyl group such as ethyl isocyanate (meth) acrylate, and the like.
Specific examples of the alkoxysilyl group-containing polymerizable unsaturated monomers include: and silicone monomers such as vinylethoxysilane, α -methacryloxypropyltrimethoxysilane, and trimethylsiloxyethyl (meth) acrylate.
Specific examples of the carboxyl group-containing α, β -ethylenically unsaturated monomer include: α, β -ethylenically unsaturated carboxylic acids such as unsaturated mono-or dicarboxylic acids (e.g., methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, and citraconic acid), and monoesters of dicarboxylic acids and monohydric alcohols; adducts of alkyl α, β -unsaturated carboxylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, di-2-hydroxyethyl fumarate, mono-2-hydroxyethyl monobutyl fumarate and polyethylene glycol mono (meth) acrylate with polycarboxylic anhydrides such as maleic acid, succinic acid, phthalic acid, hexahydrophthalic acid, tetrahydrophthalic acid, benzenetricarboxylic acid, benzenetetracarboxylic acid, "humic acid", tetrachlorophthalic acid and dodecysuccinic acid.
Among these, the monomer (M) is preferably an alkyl (meth) acrylate having an alkyl group having 3 or less carbon atoms, such as methyl (meth) acrylate or ethyl (meth) acrylate.
Further, when the polymer (P) is polymerized with the monomer (M), it is preferable to copolymerize a polymerizable unsaturated monomer having at least 1 of functional groups such as a carboxyl group, a sulfonic acid group, a phosphoric acid group, a hydroxyl group, and a dimethylamino group. This improves the interaction with the siloxane bond of the polymer (polymer layer 92) to be formed, and improves the adhesion to the surface of the light-emitting particle 91.
In the case of a polymer having a tertiary amino group such as a dimethylamino group as a monomer, the tertiary amino group that does not contribute to a reaction such as a coordinate bond is oxidized, and therefore, when exposed to high temperature, the amino group causes generation of formaldehyde as a harmful substance. Here, the oxidation of the amino group in the polymer forming the polymer layer of the coated light-emitting particle 90 can be suppressed by the coexistence of the phosphite as the antioxidant B. Further, since formaldehyde generated from the amino group in the polymer reacts irreversibly with phosphite, deterioration of the light-emitting particles due to formaldehyde can also be suppressed.
In order to prevent or suppress elution of the hydrophobic polymer from the obtained light-emitting particles 90, the hydrophobic polymer (P)) is preferably crosslinked.
Examples of the polyfunctional polymerizable unsaturated monomer that can be used as the crosslinking component include: divinylbenzene, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1, 3-butanediol di (meth) acrylate, 1, 4-butanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, neopentyl glycol dimethacrylate, trimethylolpropane triethoxy tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, allyl methacrylate, and the like.
In addition, other polymerizable unsaturated monomers may be copolymerized within a range in which the obtained hydrophobic polymer is not dissolved in the nonaqueous solvent. Examples of the other polymerizable unsaturated monomer include: the alkyl (meth) acrylate (a), the fluorine-containing compounds (B, C), and other compounds that can be used as the polymerizable unsaturated monomer for the polymer (P).
The polymer layer 92 made of a hydrophobic polymer is formed by polymerizing a monomer (M) in the presence of the light-emitting particles 91, a nonaqueous solvent, and a polymer (P).
The luminescent particles 91 and the polymer (P) are preferably mixed before the polymerization is carried out. For the mixing, for example, a homogenizer, a disperser, a bead mill, a paint shaker, a kneader, a roll mill, a ball mill, an attritor, a sand mill, or the like can be used.
In the present invention, the form of the light-emitting particles 91 used is not particularly limited, and any form such as slurry, wet cake, powder, or the like may be used.
After the light-emitting particles 91 are mixed with the polymer (P), the monomer (M) and a polymerization initiator described below are further mixed and polymerized, thereby forming a polymer layer 92 made of a polymer of the polymer (P) and the monomer (M). Thereby luminescent particles 90 may be obtained.
In this case, the number average molecular weight of the polymer (P) is preferably 1,000 to 500,000, more preferably 2,000 to 200,000, and still more preferably 3,000 to 100,000. By using the polymer (P) having a molecular weight in such a range, the polymer layer 92 can be favorably coated on the surface of the light-emitting particle 91.
The amount of the polymer (P) to be used is not particularly limited and is appropriately set according to the purpose, but is usually preferably 0.5 to 50 parts by mass, more preferably 1 to 40 parts by mass, and still more preferably 2 to 35 parts by mass, based on 100 parts by mass of the light-emitting particles 91.
The amount of the monomer (M) used is also appropriately set according to the purpose, and is not particularly limited, but is usually preferably 0.5 to 40 parts by mass, more preferably 1 to 35 parts by mass, and still more preferably 2 to 30 parts by mass, relative to 100 parts by mass of the light-emitting particles 91.
The amount of the hydrophobic polymer finally covering the surface of the light-emitting particle 91 is preferably 1 to 60 parts by mass, more preferably 2 to 50 parts by mass, and still more preferably 3 to 40 parts by mass, based on 100 parts by mass of the light-emitting particle 91.
In this case, the amount of the monomer (M) is usually preferably 10 to 100 parts by mass, more preferably 30 to 90 parts by mass, and still more preferably 50 to 80 parts by mass, based on 100 parts by mass of the polymer (P).
The thickness of the polymer layer 92 is preferably 0.5 to 100nm, more preferably 0.7 to 50nm, and still more preferably 1 to 30nm. If the thickness of the polymer layer 92 is less than 0.5nm, dispersion stability may not be obtained in many cases. If the thickness of the polymer layer 92 exceeds 100nm, it is often difficult to contain the light-emitting particles 91 at a high concentration. By coating the light-emitting particles 91 with the polymer layer 92 having the above thickness, the stability of the light-emitting particles 90 against oxygen and moisture can be further improved.
The polymerization of the monomer (M) in the presence of the light-emitting particles 91, the nonaqueous solvent, and the polymer (P) can be carried out by a known polymerization method, and is preferably carried out in the presence of a polymerization initiator.
Examples of the polymerization initiator include: dimethyl 2, 2-azobis (2-methylpropionate), azobisisobutyronitrile (AIBN), 2-azobis (2, 4-dimethylvaleronitrile), 2-azobis (2-methylbutyronitrile), benzoyl peroxide, t-butyl peroxybenzoate, t-butyl 2-ethylhexanoate, t-butyl hydroperoxide, di-t-butyl peroxide, cumene hydroperoxide, and the like. These polymerization initiators may be used alone in 1 kind, or 2 or more kinds may be used in combination.
The polymerization initiator that is hardly soluble in the nonaqueous solvent is preferably added to the mixture containing the light-emitting particles 91 and the polymer (P) in a state of being dissolved in the monomer (M).
The monomer (M) or the monomer (M) in which the polymerization initiator is dissolved may be added to the mixed solution at the polymerization temperature by the dropping method to polymerize, but it is preferable to add the monomer (M) or the monomer (M) to the mixed solution at normal temperature before the temperature rise, sufficiently mix the monomer (M) or the monomer (M) and then raise the temperature to polymerize the monomer (M).
The polymerization temperature is preferably in the range of 60 to 130 ℃ and more preferably in the range of 70 to 100 ℃. If the polymerization of the monomer (M) can be carried out at the above polymerization temperature, morphological changes (e.g., alteration, crystal growth, etc.) of the nanocrystals 911 can be suitably prevented.
After the polymerization of the monomer (M), the polymer not adsorbed on the surface of the light-emitting particle 91 is removed, and a light-emitting particle (polymer-coated light-emitting particle) 90 in which a polymer layer 92 is formed on the surface of the light-emitting particle 91 is obtained. Examples of the method for removing unadsorbed polymer include: centrifugal settling and ultrafiltration. In centrifugal sedimentation, a dispersion liquid containing the polymer-coated light-emitting particles 90 and unadsorbed polymer is rotated at a high speed, and the polymer-coated light-emitting particles 90 in the dispersion liquid are sedimented to separate unadsorbed polymer. In ultrafiltration, a dispersion containing the polymer-coated light-emitting particles 90 and the unadsorbed polymer is diluted with an appropriate solvent, and the diluted solution is passed through a filtration membrane having an appropriate pore size to separate the unadsorbed polymer from the polymer-coated light-emitting particles 90.
The polymer-coated light-emitting particle 90 can be obtained in the above manner. The polymer-coated light-emitting particles 90 may be stored in a state of being dispersed in a dispersion medium, a resin, or a polymerizable compound (i.e., in the form of a dispersion liquid), or may be stored in the form of a powder (an aggregate of the polymer-coated light-emitting particles 90) by removing the dispersion medium.
When the light-emitting particle-containing ink composition contains the polymer-coated light-emitting particles 90, the content of the polymer-coated light-emitting particles 90 is preferably 0.1 to 20% by mass, more preferably 0.5 to 15% by mass, and still more preferably 1 to 10% by mass. Similarly, when the light-emitting particle-containing ink composition includes the nanocrystals 911 not coated with the polymer layer 92, the light-emitting particles 91 contained in the hollow particles, and the silica-coated light-emitting particles 91, the content of the light-emitting particles 91 is also preferably 0.1 to 20% by mass, more preferably 0.5 to 15% by mass, and still more preferably 1 to 10% by mass. By setting the content of the polymer-coated light-emitting particles 90 (or the light-emitting particles 91) in the light-emitting particle-containing ink composition to the above range, the ejection stability of the light-emitting particle-containing ink composition can be further improved when the ink composition is ejected by an ink jet printing method. Further, the light-emitting particles 90 (or the light-emitting particles 91) are less likely to aggregate with each other, and the external quantum efficiency of the light-emitting layer (light-converting layer) obtained can be improved.
The ink composition may contain 2 or more of red light-emitting particles, green light-emitting particles, and blue light-emitting particles as the light-emitting particles 90 (or the light-emitting particles 91) containing light-emitting nanocrystals, and preferably contains only 1 of these particles. When the ink composition contains the red light-emitting particles, the content of the green light-emitting particles and the content of the blue light-emitting particles are preferably 5% by mass or less, and more preferably 0% by mass, based on the total mass of the light-emitting particles. When the ink composition contains the green light-emitting particles, the content of the red light-emitting particles and the content of the blue light-emitting particles are preferably 5% by mass or less, and more preferably 0% by mass, based on the total mass of the light-emitting particles.
1-2. Photopolymerizable Compound
The photopolymerizable compound contained in the ink composition containing luminescent nanocrystal-containing nanoparticles of the present invention is a compound that functions as a binder in a cured product and is polymerized by irradiation with light (active energy rays), and a photopolymerizable monomer or oligomer may also be used. They are basically used together with a photopolymerization initiator.
As the photopolymerizable compound, a radical polymerizable compound, a cation polymerizable compound, an anion polymerizable compound, or the like can be used, and from the viewpoint of rapid curability, a radical polymerizable compound is preferably used.
The radical polymerizable compound is, for example, a compound having an ethylenically unsaturated group. In the present specification, an ethylenically unsaturated group means a group having an ethylenically unsaturated bond (polymerizable carbon-carbon double bond). The number of ethylenically unsaturated bonds (for example, the number of ethylenically unsaturated groups) in the compound having an ethylenically unsaturated group is, for example, 1 to 4.
Examples of the compound having an ethylenically unsaturated group include: and compounds having an ethylenically unsaturated group such as a vinyl group, vinylidene group, or (meth) acryloyl group. From the viewpoint that the external quantum efficiency can be further improved, a compound having a (meth) acryloyl group is preferable, a monofunctional or polyfunctional (meth) acrylate is more preferable, and a monofunctional or difunctional (meth) acrylate is further preferable. In the present specification, "(meth) acryloyl group" means "acryloyl group" and "methacryloyl group" corresponding thereto. The same applies to "(meth) acrylate". The monofunctional (meth) acrylate means a (meth) acrylate having 1 (meth) acryloyl group, and the polyfunctional (meth) acrylate means a (meth) acrylate having 2 or more (meth) acryloyl groups.
Examples of monofunctional (meth) acrylates include: methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, dodecyl (meth) acrylate, hexadecyl (meth) acrylate, octadecyl (meth) acrylate, cyclohexyl (meth) acrylate, methoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, phenoxyethyl (meth) acrylate, nonylphenoxyethyl (meth) acrylate, glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, benzyl (meth) acrylate, phenylbenzyl (meth) acrylate, mono (2-acryloyloxyethyl) succinate, N- [2- (acryloyloxy) ethyl ] phthalimidyl, N- [2- (acryloyloxy) ethyl ] tetrahydrophthalimide, trimethylolpropane formal acrylate, and the like.
The polyfunctional (meth) acrylate is 2-functional (meth) acrylate, 3-functional (meth) acrylate, 4-functional (meth) acrylate, 5-functional (meth) acrylate, 6-functional (meth) acrylate, or the like. For example, di (meth) acrylate in which 2 hydroxyl groups of a diol compound are substituted with (meth) acryloyloxy groups, di-or tri (meth) acrylate in which 2 or 3 hydroxyl groups of a triol compound are substituted with (meth) acryloyloxy groups, and the like can be used.
Specific examples of the 2-functional (meth) acrylate include: 1, 3-butanediol di (meth) acrylate, 1, 4-butanediol di (meth) acrylate, 1, 5-pentanediol di (meth) acrylate, 3-methyl-1, 5-pentanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1, 8-octanediol di (meth) acrylate, 1, 9-nonanediol di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol hydroxypivalate diacrylate, tris (2-hydroxyethyl) isocyanurate in which 2 hydroxyl groups of the diol are substituted with (meth) acryloyloxy groups, di (meth) acrylate in which 2 hydroxyl groups of the diol obtained by adding 4 or more moles of ethylene oxide or propylene oxide to 1 mole of neopentyl glycol are substituted with (meth) acryloyloxy groups, di (meth) acrylate in which 2 moles of ethylene oxide or propylene oxide are substituted with 2 moles of ethylene oxide are added to 1 mole of bisphenol A to obtain ethylene oxide or 2 moles of propylene oxide, di (meth) acrylate obtained by adding 3 or more moles of ethylene oxide or propylene oxide to 1 mole of trimethylolpropane to obtain triol in which 2 hydroxyl groups are substituted with (meth) acryloyloxy groups, di (meth) acrylate obtained by adding 4 or more moles of ethylene oxide or propylene oxide to 1 mole of bisphenol a in which 2 hydroxyl groups are substituted with (meth) acryloyloxy groups, and the like.
Specific examples of the 3-functional (meth) acrylate include: trimethylolpropane tri (meth) acrylate, glycerol triacrylate, pentaerythritol tri (meth) acrylate, and tri (meth) acrylate obtained by adding 3 or more moles of ethylene oxide or propylene oxide to 1 mole of trimethylolpropane to obtain triol in which 3 hydroxyl groups are substituted with (meth) acryloyloxy groups.
Specific examples of the 4-functional (meth) acrylate include: pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, and the like.
Specific examples of the 5-functional (meth) acrylate include: dipentaerythritol penta (meth) acrylate, and the like.
Specific examples of the 6-functional (meth) acrylate include: dipentaerythritol hexa (meth) acrylate, and the like.
The polyfunctional (meth) acrylate may be a poly (meth) acrylate in which a plurality of hydroxyl groups of dipentaerythritol are substituted with (meth) acryloyloxy groups, such as dipentaerythritol hexa (meth) acrylate.
The (meth) acrylate compound may also be an ethylene oxide-modified phosphoric acid (meth) acrylate having a phosphoric acid group, an ethylene oxide-modified alkyl phosphoric acid (meth) acrylate, or the like.
In the ink composition of the present invention, when the curable component is composed of only the photopolymerizable compound or the curable component is composed of the photopolymerizable compound as a main component, it is more preferable to use a 2-or more-functional photopolymerizable compound having 2 or more polymerizable functional groups in 1 molecule as an essential component because the durability (strength, heat resistance, etc.) of the cured product can be further improved.
From the viewpoint of excellent viscosity stability in preparing the ink composition, more excellent ejection stability, and the viewpoint of being able to suppress a decrease in coating film smoothness caused by curing shrinkage in the production of a light-emitting particle coating film, it is preferable to use a monofunctional (meth) acrylate in combination with a polyfunctional (meth) acrylate.
The molecular weight of the photopolymerizable compound is, for example, 50 or more, and may be 100 or more or 150 or more. The molecular weight of the photopolymerizable compound is, for example, 500 or less, and may be 400 or less or 300 or less. From the viewpoint of easily satisfying both the viscosity as an inkjet ink and the volatility of the ink after ejection, the viscosity is preferably 50 to 500, and more preferably 100 to 400.
From the viewpoint of reducing the surface tackiness (stickiness) of a cured product of the ink composition, a radical polymerizable compound having a cyclic structure is preferably used as the photopolymerizable compound. The cyclic structure may be an aromatic ring structure or a non-aromatic ring structure. The number of cyclic structures (the total of the number of aromatic rings and non-aromatic rings) is 1 or 2 or more, preferably 3 or less. The number of carbon atoms constituting the cyclic structure is, for example, 4 or more, preferably 5 or more, or 6 or more. The number of carbon atoms is, for example, 20 or less, preferably 18 or less.
The aromatic ring structure is preferably a structure having an aromatic ring having 6 to 18 carbon atoms. Examples of the aromatic ring having 6 to 18 carbon atoms include benzene ring, naphthalene ring, phenanthrene ring, and anthracene ring. The aromatic ring structure may have an aromatic heterocyclic ring structure. Examples of the aromatic heterocyclic ring include a furan ring, a pyrrole ring, a pyran ring, and a pyridine ring. The number of aromatic rings may be 1, 2 or more, preferably 3 or less. The organic group may have a structure in which 2 or more aromatic rings are bonded by a single bond (for example, a biphenyl structure).
The non-aromatic ring structure is preferably a structure having an alicyclic ring having 5 to 20 carbon atoms, for example. Examples of the alicyclic ring having 5 to 20 carbon atoms include cycloalkane rings such as cyclopentane ring, cyclohexane ring, cycloheptane ring, and cyclooctane ring; a cycloalkene ring such as a cyclopentene ring, a cyclohexene ring, a cycloheptene ring, a cyclooctene ring or the like; dioxane, and the like. The alicyclic ring may be a condensed ring such as a bicycloundecane ring, a decahydronaphthalene ring, a norbornene ring, a norbornadiene ring, an isobornyl ring, etc. The non-aromatic ring structure may have a structure having a non-aromatic heterocyclic ring. Examples of the non-aromatic heterocyclic ring include a tetrahydrofuran ring, a pyrrolidine ring, a tetrahydropyran ring, and a piperidine ring.
The radical polymerizable compound having a cyclic structure is preferably a monofunctional or polyfunctional (meth) acrylate having a cyclic structure, and more preferably a monofunctional (meth) acrylate having a cyclic structure. Specifically, phenoxyethyl (meth) acrylate, phenoxybenzyl (meth) acrylate, biphenyl (meth) acrylate, isobornyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, trimethylolpropane formal acrylate, and the like can be preferably used.
The content of the radical polymerizable compound having a cyclic structure is preferably 3 to 85% by mass, more preferably 5 to 65% by mass, even more preferably 10 to 45% by mass, and particularly preferably 15 to 35% by mass, based on the total mass of the photopolymerizable compounds in the ink composition, from the viewpoint of easily suppressing surface tackiness (stickiness) of the ink composition, easily obtaining a viscosity suitable for an ink jet ink, and easily obtaining excellent ejection properties.
From the viewpoint of easily obtaining excellent ejection properties, the ink composition preferably uses a radical polymerizable compound having a linear structure having 3 or more carbon atoms, and more preferably uses a radical polymerizable compound having a linear structure having 4 or more carbon atoms. The linear structure represents a hydrocarbon chain having 3 or more carbon atoms. In the radical polymerizable compound having a linear structure, a hydrogen atom directly bonded to a carbon atom constituting the linear structure may be substituted with a methyl group or an ethyl group, and the number of substitutions is preferably 3 or less. In the radical polymerizable compound having a linear structure of 4 or more carbon atoms, the linear structure is preferably a structure in which atoms other than hydrogen atoms are connected without branching, and may have a hetero atom such as an oxygen atom in addition to a carbon atom and a hydrogen atom. That is, the linear structure is not limited to a structure in which 3 or more carbon atoms are connected in a linear state, and may be a structure in which 3 or more carbon atoms are connected in a linear state via a hetero atom such as an oxygen atom. The linear structure may have an unsaturated bond, but is preferably composed of only a saturated bond. The number of carbon atoms constituting the linear structure is preferably 5 or more, more preferably 6 or more, and further preferably 7 or more. The number of carbon atoms constituting the linear structure is preferably 25 or less, more preferably 20 or less, and further preferably 15 or less. From the viewpoint of ejection properties, a radical polymerizable compound having a linear structure in which the total number of carbon atoms is 3 or more (the carbon atoms of a methyl group or an ethyl group in which a hydrogen atom directly bonded to a carbon atom forming the linear structure is substituted are not included) preferably does not have a cyclic structure.
The linear structure is preferably a structure having a linear alkyl group having 4 or more carbon atoms, for example. Examples of the linear alkyl group having 4 or more carbon atoms include butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, and pentadecyl. As the radical polymerizable compound having such a structure, an alkyl (meth) acrylate in which the straight-chain alkyl group is directly bonded to a (meth) acryloyloxy group can be preferably used.
The linear structure is preferably a structure having a linear alkylene group having 4 or more carbon atoms, for example. Examples of the linear alkylene group having 4 or more carbon atoms include butylene group, pentylene group, hexylene group, heptylene group, octylene group, nonylene group, decylene group, undecylene group, dodecylene group, tridecylene group, tetradecylene group, and pentadecylene group. As the radical polymerizable compound having such a structure, alkylene glycol di (meth) acrylate in which 2 (meth) acryloyloxy groups are bonded via the above-mentioned linear alkylene group can be preferably used.
The linear structure is preferably a structure in which a linear alkyl group and 1 or more linear alkylene groups are bonded to each other via an oxygen atom (a structure having an alkyl (poly) oxyalkylene group), for example. The number of the linear alkylene groups is preferably 2 or more and 6 or less. When the number of the linear alkylene groups is 2 or more, 2 or more alkylene groups may be the same or different. The number of carbon atoms of the straight-chain alkyl group and the straight-chain alkylene group may be 1 or more, and may be 2 or more, or 3 or more, but is preferably 4 or less. Examples of the straight-chain alkyl group include a methyl group, an ethyl group, and a propyl group, in addition to the straight-chain alkyl group having 4 or more carbon atoms. Examples of the linear alkylene group include a methylene group, an ethylene group and a propylene group, in addition to the above-mentioned linear alkylene group having 4 or more carbon atoms. As the radical polymerizable compound having such a structure, an alkyl (poly) oxyalkylene (meth) acrylate in which the alkyl (poly) oxyalkylene group is directly bonded to a (meth) acryloyloxy group can be preferably used.
The content of the radical polymerizable compound having a linear structure having 3 or more carbon atoms is preferably 10 to 90% by mass, more preferably 15 to 80% by mass, and particularly preferably 20 to 70% by mass, based on the total mass of the photopolymerizable compounds in the ink composition, from the viewpoint of easily obtaining a suitable viscosity as an ink jet ink and easily obtaining excellent ejection properties, from the viewpoint of excellent curability of the ink composition, and from the viewpoint of easily suppressing surface tackiness (stickiness) of the ink composition.
As the photopolymerizable compound, 2 or more kinds of radical polymerizable compounds are preferably used from the viewpoint of excellent surface uniformity of the pixel portion, and more preferably, the radical polymerizable compound having a cyclic structure and the radical polymerizable compound having a linear structure having 3 or more carbon atoms are used in combination. When the amount of the nanoparticles including the luminescent nanocrystals is increased in order to improve the external quantum efficiency, the surface uniformity of the pixel portion may be reduced, but even in such a case, the combination of the photopolymerizable compounds tends to provide a pixel portion having excellent surface uniformity.
When the radical polymerizable compound having a cyclic structure and the radical polymerizable compound having a linear structure having 3 or more carbon atoms are used in combination, the radical polymerizable compound having 3 or more carbon atomsContent M of a straight-chain radically polymerizable Compound L Content M of the radical polymerizable Compound having a Cyclic Structure C Mass ratio (M) of L /M C ) From the viewpoint of excellent surface uniformity of the pixel portion, the thickness is preferably 0.05 to 5, more preferably 0.1 to 3.5, and particularly preferably 0.1 to 2.
The photopolymerizable compound is preferably alkali-insoluble from the viewpoint of easily obtaining a pixel portion (cured product of the ink composition) excellent in reliability. In the present specification, the photopolymerizable compound being alkali-insoluble means that the amount of the photopolymerizable compound dissolved in a 1 mass% potassium hydroxide aqueous solution at 25 ℃ is 30 mass% or less based on the total mass of the photopolymerizable compound. The amount of the photopolymerizable compound dissolved is preferably 10% by mass or less, and more preferably 3% by mass or less.
The content of the photopolymerizable compound contained in the ink composition is preferably 70 to 95% by mass, more preferably 75 to 93% by mass, and still more preferably 80 to 90% by mass, based on the total mass of the ink composition, from the viewpoint of easily obtaining a viscosity suitable for an inkjet ink, from the viewpoint of improving the curability of the ink composition, from the viewpoint of improving the solvent resistance and abrasion resistance of the pixel portion (cured product of the ink composition), and from the viewpoint of obtaining more excellent optical characteristics (for example, external quantum efficiency).
1-3. Photopolymerization initiator
The photopolymerization initiator used in the ink composition of the present invention contains 2 or more types of acylphosphine oxide-based compounds. This makes it possible to reduce the viscosity of the ink and further to prevent the photopolymerization initiator from being deposited with storage, because the ink has excellent solubility in the polymerizable compound. Further, a coating film having excellent internal curability and a cured film having a small initial coloring degree can be formed. In particular, the ink composition of the present invention is suitable for an ultraviolet light emitting diode (UV-LED) having a narrow-band spectral output in the ± 15 nm region centered around a specific wavelength of 365 nm, 385 nm, 395 nm or 405 nm.
Particularly, it is preferable to use 1 or more types of monoacylphosphine oxide-based compounds and 1 or more types of bisacylphosphine oxide-based compounds in combination as the photopolymerization initiator. By using these compounds in combination, it is possible to surely achieve both the reduction in the viscosity of the ink and the suppression of the deposition of the photopolymerization initiator.
The monoacylphosphine oxide-based compound is not particularly limited, and examples thereof include: 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ethoxyphenyl- (2,4,6-trimethylbenzoyl) phosphine oxide, 2,4,6-triethylbenzoyldiphenylphosphine oxide, 2,4,6-triphenylbenzoyldiphenylphosphine oxide. Among them, 2,4, 6-trimethylbenzoyldiphenylphosphine oxide is preferable.
Commercially available monoacylphosphine oxide-based compounds include, for example: omnirad TPO (2, 4, 6-trimethylbenzoyl-diphenyl-phosphine oxide), omnirad TPO-L (ethoxyphenyl- (2, 4, 6-trimethylbenzoyl) phosphine oxide) (supra, by IGM Resins b.v. company).
The bisacylphosphine oxide-based compound is not particularly limited, and examples thereof include: bis (2, 4, 6-trimethylbenzoyl) phenylphosphine oxide, bis- (2, 6-dimethoxybenzoyl) -2, 4-trimethylpentylphosphine oxide. Among these, bis (2, 4, 6-trimethylbenzoyl) phenylphosphine oxide is preferable.
Examples of commercially available bisacylphosphine oxide compounds include: omnirad 819 (bis (2, 4, 6-trimethylbenzoyl) phenylphosphine oxide) (manufactured by IGM Resins B.V. Co.).
The content of the photopolymerization initiator is preferably 1 to 15% by mass, more preferably 2 to 12% by mass, even more preferably 3 to 9% by mass, and particularly preferably 3 to 7% by mass, based on 100% by mass of the photopolymerizable compound, from the viewpoints of solubility in the photopolymerizable compound, curability of the ink composition, and stability with time (maintenance stability of external quantum efficiency) of the pixel portion (cured product of the ink composition).
The content ratio of the acylphosphine oxide compound in the photopolymerization initiator is preferably 50 to 100% by mass, more preferably 60 to 100% by mass, and particularly preferably 70 to 100% by mass, from the viewpoint of curability of the ink composition.
The content ratio of the bisacylphosphine oxide compound to the monoacylphosphine oxide compound (% by mass of the bisacylphosphine oxide compound/% by mass of the monoacylphosphine oxide compound) is preferably 0.1 to 6.0, more preferably 0.2 to 5.0, and particularly preferably 0.5 to 4.0, from the viewpoint of a large molar absorption coefficient and solubility in the photopolymerizable compound.
The ink composition of the present invention may further contain a photopolymerization initiator other than the acylphosphine oxide-based compound. Examples of other photopolymerization initiators include: an alkyl-phenyl-ketone photopolymerization initiator, a titanocene-based alkyl-phenyl-ketone photopolymerization initiator, an oxime-ester photopolymerization initiator, and an oxyphenyl-acetate photopolymerization initiator. The content of the photopolymerization initiator other than the acylphosphine oxide compound is preferably 0 to 40% by mass, more preferably 0 to 30% by mass, even more preferably 0 to 20% by mass, and particularly preferably 0 to 10% by mass, based on 100% by mass of the photopolymerization initiator.
1-4 antioxidant
The ink composition of the present invention contains 1 or more compounds selected from the group consisting of compounds having a hydroxyphenyl group and compounds having a phosphite structure as an antioxidant. The ink composition of the present invention contains the antioxidant, and thus can suppress a decrease in storage stability of the ink composition and a decrease in external quantum efficiency of a coating film due to heat.
Preferably, a first antioxidant a and a second antioxidant B are used as the antioxidants, the first antioxidant a containing at least 1 or more compounds having a hydroxyphenyl group, and the second antioxidant B containing at least 1 or more compounds having a phosphite ester structure. By using them in combination, a higher antioxidant effect can be obtained.
1-4-1. First antioxidant A
The first antioxidant a contains 1 or more kinds of compounds having a hydroxyphenyl group. The compound can capture peroxy radicals with high activity in the initial stage of oxidation reaction to provide metastable hydrogen peroxide.
Specific examples of the first antioxidant a containing a compound having a hydroxyphenyl group include: "tetrakis [ methylene-3 (3 ',5' -di-t-butyl-4 ' -hydroxyphenyl) propionate ] methane" (melting point 110 to 130 ℃ C., molecular weight 1178) commercially available in the form of IRGANOX 1010 (product name, manufactured by BASF Japan K.K.), adekastab AO-60 (product name, manufactured by ADEKA Co., ltd.), SUMILIZER BP-101 (product name, manufactured by Sumitomo chemical Co., ltd.), TOMINOX TT (product name, manufactured by Gifford chemical Co., ltd.); "2,2' -thiodiethyl bis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ]" (melting point 63 ℃ C., molecular weight 643) sold as IRGANOX 1035 (product name: manufactured by BASF Japan K.); octadecyl-3- (3 ',5' -di-tert-butyl-4 ' -hydroxyphenyl) propionate (melting point 50-55 ℃ C., molecular weight 531) commercially available in the form of IRGANOX 1076 (product name; manufactured by BASF Japan), adekastab AO-50 (product name; manufactured by ADEKA K.K.), SUMILIZER BP-76 (product name; manufactured by Sumitomo chemical Co., ltd.), TOMINOX SS (product name; manufactured by Gifford chemical Co., ltd.); "N, N' -hexamethylenebis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionamide ]" commercially available as IRGANOX 1098 (product name, manufactured by BASF Japan K.K.) "(melting point: 156 to 161 ℃ C., molecular weight: 637); isooctyl 3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate (melting point 63-78 ℃ C., molecular weight 643) commercially available as IRGANOX 1135 (product name, manufactured by BASF Japan K.K.); "2,4,6-tris (3 ',5' -di-t-butyl-4 ' -hydroxybenzyl) mesitylene" commercially available as IRGANOX 1330 (product name, manufactured by BASF Japan K.K.) and Adekab AO-330 (product name, manufactured by ADEKA) (melting point 240-245 ℃, molecular weight 775); "2, 4-bis [ (dodecylthio) methyl ] -6-methylphenol" (melting point 27-29 ℃ C., molecular weight 537) commercially available in the form of IRGANOX 1726 (product name, BASF Japan K.K.); calcium bis [3, 5-di (tert-butyl) -4-hydroxybenzyl (ethoxy) phosphonite ] available commercially as IRGANOX 1425WL (product name, BASF Japan Co., ltd.) (melting point 90-300 ℃ C., molecular weight 695); "2, 4-bis (octylthiomethyl) -6-methylphenol" (melting point: about 14 ℃ C., molecular weight: 425) commercially available in the form of IRGANOX 1520L (manufactured by BASF Japan K.K.) or the like; ethylene bis (oxyethylene) propionate bis [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate ] commercially available as IRGANOX 245 (product name, manufactured by BASF Japan) (melting point 76-79 ℃ C., molecular weight 587); "1, 6-hexanediol bis [3- (3, 5-di-t-butyl-4-hydroxyphenyl) propionate ]" commercially available as IRGANOX 259 (product name, manufactured by BASF Japan K.K.) "(melting point 104 to 108 ℃ C., molecular weight 639); "tris (3, 5-di-tert-butyl-4-hydroxybenzyl) isocyanate" (melting point 218-223 ℃ C., molecular weight 784) commercially available in the form of IRGANOX 3114 (product name, manufactured by BASF Japan K.K.), adekab AO-20 (product name, manufactured by ADEKA K.K.); "4- [ [4, 6-bis (octylthio) -1,3, 5-triazin-2-yl ] amino ] -2, 6-di-t-butylphenol" (melting point: 91 to 96 ℃ C., molecular weight: 589) commercially available in the form of IRGANOX 565 (product name, manufactured by BASF Japan K.K.); "diethyl 3, 5-di-tert-butyl-4-hydroxybenzylphosphonate" commercially available in the form of IRGAMOD 295 (product name, manufactured by BASF Japan K.K.) (melting point 116 to 121 ℃ C., molecular weight 356); "3, 9-bis [2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy ] -1, 1-dimethylethyl ] -2,4,8, 10-tetraoxaspiro [5.5] undecane (melting point 110 to 120 ℃ C., molecular weight 741)" commercially available in the form of SUMILIZER GA-80 (product name, manufactured by Sumitomo chemical Co., ltd.), adekastab AO-80 (product name, manufactured by ADEKA Co., ltd.), and the like; "2- [1- (2-hydroxy-3, 5-di-t-pentylphenyl) ethyl ] -4, 6-di-t-pentylphenyl acrylate" (melting point 127 ℃, molecular weight 549), which is commercially available in the form of SUMILIZER GS (product name, sumitomo chemical Co., ltd.); "1, 3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane" (melting point 183 to 185 ℃ C., molecular weight 545) commercially available in the form of Adekastab AO-30 (product name, manufactured by ADEKA); "4,4' -butylidenebis (3-methyl-6-t-butyl) phenol" commercially available as Adekastab AO-40 (product name, manufactured by ADEKA corporation) or the like (melting point 210 to 214 ℃, molecular weight 383); "2,2' -methylenebis (6-t-butyl-p-cresol)" commercially available as SUMILIZER MDP-S (product name, manufactured by Sumitomo chemical Co., ltd.) (melting point 118 to 128 ℃ C., molecular weight 341); "4,4' -thiobis (6-t-butyl-m-cresol)" commercially available in the form of SUMILIZER WX-R (product name, manufactured by Sumitomo chemical Co., ltd.) (melting point 160 to 165 ℃ C., molecular weight 359); "butylhydroxytoluene" (melting point 70 ℃, molecular weight 220) commercially available in the form of ANTAGE BHT (product name, available from Kanto chemical Co., ltd.) or SUMILIZER BHT (product name, available from Sumitomo chemical Co., ltd.); "2, 5-di-tert-amylhydroquinone" (melting point 179-180 ℃ C., molecular weight 250) commercially available in the form of ANTAGE DAH (product name, available from Kayokoku chemical Co., ltd.); "2, 5-di-tert-butylhydroquinone" (melting point 213 to 214 ℃ C., molecular weight 222) commercially available in the form of ANTAGE DBH (product name, available from Kayokoku chemical Co., ltd.); "4,4' -butylidenebis (6-t-butylmetacresol)" commercially available in the form of ANGATE W-300 (product name, available from Kayokoku chemical Co., ltd.) (melting point 209 ℃ C., molecular weight 383); "2,2' -methylenebis (6-tert-butyl-p-cresol)" (melting point 118 to 128, molecular weight 341) commercially available in the form of ANTAGE W-400 (product name, available from Kayokoku chemical Co., ltd.); "2,2' -methylenebis (6-tert-butyl-4-ethylphenol)" (melting point 123, molecular weight 369) commercially available in the form of ANTAGE W-500 (product name, available from Kayokoku chemical Co., ltd.).
In addition, from the viewpoint of being able to suppress a decrease in storage stability of the ink composition and a decrease in external quantum efficiency of the cured coating film due to heat, the first antioxidant a more preferably has a molecular weight of 500 to 1500, and a softening point and a melting point of 70 to 250 ℃.
Further, from the viewpoint of being able to suppress a decrease in storage stability of the ink composition and a decrease in external quantum efficiency of a cured coating film due to heat, the first antioxidant a is more preferably a compound represented by the following general formula (I) as the compound having a hydroxyphenyl group.
Figure BDA0004092365490000531
In the above general formula (I), M 1 Represents 1, 4-phenylene, trans-1, 4Cyclohexylene, 2,4,8, 10-tetraoxaspiro [5,5 ]]Undecyl, C1-20 hydrocarbon group, 1 or 2 or more-CH in the hydrocarbon group 2 May be substituted by-O-insofar as the oxygen atoms are not directly adjacent-CO-, -COO-, -OCO-, -NH-, any hydrogen atom in the hydrocarbon group may be substituted with a substituted phenyl group, X 1 Represents an alkylene group having 1 to 15 carbon atoms or-OCH 2 -、-CH 2 O-, -COO-, -OCO-, -CH = CH-COO-, -CH = CH-OCO-, -COO-CH = CH-, -OCO-CH = CH-, -C.ident.C-, a single bond, 1, 4-phenylene or trans-1, 4-cyclohexylene, which may be the same or different from each other, 1 or 2 or more-CH in the alkylene group 2 May be substituted by-O-insofar as the oxygen atoms are not directly adjacent-CO-, -COO-, -OCO-, any hydrogen atom of the 1, 4-phenylene group may be substituted with a hydrocarbon group having 1 to 6 carbon atoms, R 11 And R 12 Each independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, and k represents an integer of 2 to 6.
Examples of the compounds represented by the above formula (I) include the following formulae (I-1) to (I-6).
Figure BDA0004092365490000541
Specific examples of the first antioxidant a containing the compound represented by the above general formula (I) include: IRGANOX 1010, IRGANOX 1098, IRGANOX 245, IRGANOX259 (manufactured by BASF Japan K.K., supra), adekastab AO-30, adekastab AO-60, adekastab AO-80 (manufactured by ADEKA, inc., supra), sumilizer BP-101, sumilizer GA-80 (manufactured by Sumilizer chemical Co., ltd.), KEMINOX101 (manufactured by Chemipro Kasei K.K.), and the like.
The content of the first antioxidant a in the ink composition is preferably 0.05 to 3.0% by mass, more preferably 0.1 to 2.0% by mass, and still more preferably 0.1 to 1.0% by mass, based on 100% by mass of the ink composition. If the content is less than this range, the antioxidant effect is low, and therefore the effects of suppressing the increase in the ink viscosity and preventing the decrease in the external quantum efficiency of the coating film due to heat are less than expected, and if the content is more than this range, the antioxidant functions as a plasticizer and inhibits the curing of the ink composition, which is not preferable.
1-4-2. Second antioxidant B
The second antioxidant B contains 1 or more compounds having a phosphite ester structure. The second antioxidant B decomposes hydrogen peroxide generated by the first antioxidant a to provide a stable alcohol compound.
Specific examples of the antioxidant B containing a compound having a phosphite ester structure include: "tris (4-nonylphenyl) phosphite" (melting point 6 ℃ C., molecular weight 689) commercially available in the form of Adekastab 1178 (product name, manufactured by ADEKA K.K.), JP-351 (product name, manufactured by Tokyo chemical industries, ltd.), or the like; "tris (2, 4-di-t-butylphenyl) phosphite" (melting point 183 ℃ C., molecular weight 647) commercially available in the form of Adekastab 2112 (product name, manufactured by ADEKA K.K.), IRGAFOS168 (product name, manufactured by BASF Japan K.K.), JP-650 (product name, manufactured by North City chemical industry Co., ltd.), and the like; "2,4,8,10-tetrakis (1, 1-dimethylethyl) -6- [ (2-ethylhexyl) oxy ] -12H-dibenzo [ d, g ] [1,3,2] dioxaphosph-ene heterocyclooctene" (melting point 148 ℃ C., molecular weight 583) commercially available as Adekab HP-10 (product name, manufactured by ADEKA Co., ltd.), "3,9-bis (octadecyloxy) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5.5] undecane" (softening point 52 ℃ C., molecular weight 733) commercially available as Adekab PEP-8 (product name, manufactured by ADEKA Co., ltd.), "3,9-bis (2,4-di-t-butylphenoxy) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5.5] undecane" (softening point 52 ℃ C., molecular weight 733) commercially available as Adekab HP-10 (product name, manufactured by ADEKA Co., ltd.), "3,9-5-bis (3,4-di-t-butyl-2-phenoxy) -2,9-5-bis (product name, manufactured by ADEK Co., manufactured by ADEKA., 2,604) commercially available as Adekab (melting point 2,8,8,8,8,5,5,8,5,5,60) and the like C, molecular weight 633); "triphenyl phosphite" (melting point 25 ℃, molecular weight 310) commercially available in the form of Adekastab TPP (product name, manufactured by ADEKA corporation), JP-360 (product name, manufactured by north chemical industry co., ltd.), and the like; trinonylphenyl phosphite (melting point: 20 ℃ C. Or lower, molecular weight: 689) commercially available in the form of JP-351 (product name, manufactured by Tokyo chemical industries, ltd.) or the like; "triethyl phosphite" (melting point-122 ℃ C., molecular weight 166) commercially available in the form of JP-3CP "tricresyl phosphite" (melting point 20 ℃ C. Or lower, molecular weight 352), JP-302 (product name, manufactured by Tokyo chemical Co., ltd.), or the like; "Tri (2-ethylhexyl) phosphite" (melting point: 20 ℃ C. Or lower, molecular weight: 419) commercially available in the form of JP-308E (product name, manufactured by Tokyo chemical industries, ltd.); tridecyl phosphite (melting point 20 ℃ C. Or lower, molecular weight 503) commercially available in the form of JP-310 (product name, manufactured by chemical industries of Tokyo, ltd.), adekastab 3010 (product name, manufactured by ADEKA, ltd.), or the like; trilauryl phosphite (melting point: 20 ℃ C. Or lower, molecular weight: 589) commercially available in the form of JP-312L (product name, manufactured by Tokyo chemical industries, ltd.) or the like; tritridecyl phosphite (melting point: 20 ℃ C. Or lower, molecular weight: 629) commercially available in the form of JP-333 (product name, manufactured by Tokyo chemical industries, ltd.) or the like; "triolefin phosphite" (melting point: 20 ℃ C. Or lower, molecular weight: 833) commercially available in the form of JP-318-O (product name, manufactured by Tokyo chemical Co., ltd.) or the like; "Diphenylmono (2-ethylhexyl) phosphite" (melting point: 20 ℃ C. Or lower, molecular weight: 346) commercially available in the form of JPM-308 (product name, manufactured by Tokyo chemical industries, ltd.), adekastab C (product name, manufactured by ADEKA, ltd.), or the like; "Diphenylmonodecyl phosphite" (melting point 18 ℃ C., molecular weight 375) commercially available in the form of JPM-311 (product name, manufactured by Tokyo chemical industries, ltd.); "Diphenyl Mono (tridecyl) phosphite" (melting point: 20 ℃ C. Or lower, molecular weight: 416) commercially available in the form of JPM-313 (product name, manufactured by Tokyo chemical industries, ltd.); commercially available as JA-805 (product name, manufactured by NIPPON CHEMICAL CO., LTD.), adekab 1500 (product name, manufactured by ADEKA, inc.) (melting point 20 ℃ C. Or lower, molecular weight 1112); "bis (decyl) pentaerythritol diphosphite" (melting point: 20 ℃ C. Or lower, molecular weight: 508) commercially available in the form of JPE-10 (product name, manufactured by Tokyo chemical industries, ltd.); "tristearyl phosphite" (melting point 45 to 52 ℃ C., molecular weight 839) commercially available in the form of JP-318E (product name, manufactured by Tokyo chemical industries, ltd.); "tetrakis (2, 4-di-t-butylphenyl) -1, 1-biphenyl-4, 4' -diyl bisphosphonate" (melting point 85 to 100 ℃ C., molecular weight 1035) commercially available in the form of HOSTANOX P-EPQ (product name, manufactured by Clarian chemical Co., ltd.); "Tetrakis (2, 4-di-t-butyl-5-methylphenyl) -4,4' -biphenylene diphosphonate" (melting point 235-240 ℃ C., molecular weight 1092) commercially available in the form of GSY-P100 (product name, made by Sakai chemical industry Co., ltd.) or the like.
The antioxidant B is more preferably a compound having a molecular weight of 500 to 1500 inclusive and a softening point and a melting point of 70 to 250 ℃ inclusive, from the viewpoint of suppressing a decrease in storage stability of the ink composition and a decrease in external quantum efficiency of a cured coating film due to heat.
Further, from the viewpoint of being able to suppress a decrease in storage stability of the ink composition and a decrease in external quantum efficiency of the cured coating film due to heat, the antioxidant B is more preferably a compound having a phosphite structure represented by the following general formula (II) or general formula (III).
Figure BDA0004092365490000571
(in the general formula (II), R 20 To R 24 Each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, and 1 methyl group in the alkyl group may be substituted with an aryl group).
Figure BDA0004092365490000572
(in the general formula (III), R 30 To R 37 Each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, R 3a 、R 3b Each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, or R 3a And R 3b Form a ring structure, Z 31 Represents a straight-chain alkyl group or an aryl group having 1 to 10 carbon atoms, and any hydrogen atom of the aryl group may be substituted with a straight-chain or branched alkyl group having 1 to 6 carbon atoms).
Examples of the compound represented by the formula (II) include the following formulae (II-1) to (II-3).
Figure BDA0004092365490000573
Specific examples of the antioxidant B containing the compound represented by the above general formula (II) include: adekastab PEP-24, adekastab PEP-36, adekastab PEP-45 (manufactured by ADEKA, inc., supra), and the like.
The compound represented by the above formula (III) includes, for example, a compound represented by the formula (III-1) or (III-2).
Figure BDA0004092365490000581
Specific examples of the antioxidant B containing the compound represented by the above general formula (III) include: adekastab 2112, adekastab HP-10 (manufactured by ADEKA, inc., supra), and the like.
The content of the antioxidant B in the ink composition is preferably 0.01 to 3.0% by mass, more preferably 0.05 to 2.0% by mass, and still more preferably 0.1 to 1.0% by mass, based on 100% by mass of the ink composition. If the content is less than this range, the antioxidant effect is low, and therefore the effects of suppressing an increase in the viscosity of the ink and preventing a decrease in the external quantum efficiency of the coating film due to heat are less than expected, and if the content is more than this range, the antioxidant functions as a plasticizer and inhibits curing of the ink composition, which is not preferable.
The total content of the first antioxidant a and the second antioxidant B in the present invention is preferably 0.01 to 5% by mass, more preferably 0.05 to 3% by mass, and particularly preferably 0.1 to 2% by mass, based on the total amount of the ink composition. When the amount is within the above range, the ink composition can be satisfactorily dissolved, deposition of unnecessary components is small, and the light emission characteristics (external quantum efficiency) of the obtained coating film are not easily affected.
The mass ratio (a/B) of the first antioxidant a and the second antioxidant B in the present invention is preferably 0.05 to 5.0, more preferably 0.1 to 4.0, still more preferably 0.15 to 3.0, and particularly preferably 0.2 to 2.0. When the amount is within the above range, the heat resistance of the coating film is high, and the light emission characteristics (external quantum efficiency) of the coating film are less likely to be affected.
1-5. Light diffusing particles
The ink composition of the present invention preferably contains light diffusing particles. The light diffusing particles are, for example, optically inactive inorganic fine particles. The light diffusion particles can scatter light from the light source section irradiated to the light emitting layer (light conversion layer).
Examples of the material constituting the light diffusion particles include: elemental metals such as tungsten, zirconium, titanium, platinum, bismuth, rhodium, palladium, silver, tin, platinum, and gold; metal oxides such as silica, barium sulfate, barium carbonate, calcium carbonate, talc, titanium oxide, clay, kaolin, barium sulfate, barium carbonate, calcium carbonate, alumina white, titanium oxide, magnesium oxide, barium oxide, aluminum oxide, bismuth oxide, zirconium oxide, and zinc oxide; metal carbonates such as magnesium carbonate, barium carbonate, bismuth subcarbonate, and calcium carbonate; metal hydroxides such as aluminum hydroxide; and composite oxides such as barium zirconate, calcium titanate, barium titanate, and strontium titanate, and metal salts such as bismuth subnitrate.
Among these, the material constituting the light diffusion particles preferably contains at least 1 selected from the group consisting of titanium oxide, aluminum oxide, zirconium oxide, zinc oxide, calcium carbonate, barium sulfate, and silica, more preferably contains at least one selected from the group consisting of titanium oxide, barium sulfate, and calcium carbonate, and particularly preferably contains titanium oxide, from the viewpoint of further improving the effect of reducing light leakage.
When titanium oxide is used, titanium oxide subjected to surface treatment is preferable from the viewpoint of dispersibility. As a surface treatment method of titanium oxide, a known method is used, and more preferably, a surface treatment containing at least alumina is used.
The surface-treated titanium oxide containing alumina is a treatment in which at least alumina is precipitated on the surface of titanium oxide particles, and silica or the like may be used in addition to alumina. In addition, alumina or silica also includes their hydrates.
When the titanium oxide particles are subjected to surface treatment containing alumina in this manner, the surfaces of the titanium oxide particles are uniformly surface-coated, and the titanium oxide particles subjected to at least surface treatment with alumina are used, the dispersibility of the titanium oxide particles is improved.
In addition, when the titanium oxide particles are subjected to the treatment with silica and the treatment with alumina, the alumina treatment and the silica treatment may be performed simultaneously, and particularly, the alumina treatment may be performed first and then the silica treatment may be performed. In the case where the alumina treatment and the silica treatment are performed separately, the treatment amounts of alumina and silica are preferably larger than those of alumina.
The surface treatment of the titanium oxide with a metal oxide such as alumina or silica can be performed by a wet method. For example, titanium oxide particles subjected to surface treatment with alumina or silica can be produced in the following manner.
Titanium oxide particles (number-average primary particle diameter: 200 to 400 nm) are dispersed in water at a concentration of 50 to 350g/L to prepare an aqueous slurry, and a water-soluble silicate or a water-soluble aluminum compound is added thereto. Then, an alkali or an acid is added to neutralize the titanium oxide particles, thereby depositing silica or alumina on the surfaces of the titanium oxide particles. Subsequently, the resultant was filtered, washed and dried to obtain a target surface-treated titanium oxide. When sodium silicate is used as the water-soluble silicate, it can be neutralized with an acid such as sulfuric acid, nitric acid, or hydrochloric acid. On the other hand, when aluminum sulfate is used as the water-soluble aluminum compound, it can be neutralized with an alkali such as sodium hydroxide or potassium hydroxide.
In the present invention, as the dispersant for the light-diffusing particles, a polymer dispersant is preferably used, and a polymer dispersant having an amine value is more preferably used. Examples thereof include: <xnotran> Disparlon DA-325 (:14 mgKOH/g), disparlon DA-234 (:20 mgKOH/g), DA-703-50 (:40 mgKOH/g) (, ), ajisper PB821 (:10 mgKOH/g), ajisper PB822 (:17 mgKOH/g), ajisper PB824 (:17 mgKOH/g), ajisper PB881 (:17 mgKOH/g) (, ajinomoto Fine-Techno ), efka PU4046 (:19 mgKOH/g), efka PX4300 (:56 mgKOH/g), efka PX4320 (:28 mgKOH/g), efka PX4330 (:28 mgKOH/g), efka PX4350 (:12 mgKOH/g), efka PX4700 (:60 mgKOH/g), efka PX4701 (:40 mgKOH/g), efka4731 (:25 mgKOH/g), efka-4732 (:25 mgKOH/g), efka4751 (:12 mgKOH/g), dispex Ultra FA4420 (:35 mgKOH/g), dispex Ultra FA4425 (:35 mgKOH/g) (, BASF Japan ), DISPERBYK-162, DISPERBYK-163, DISPERBYK-164, DISPERBYK-180, DISPERBYK-109, DISPERBYK-2000, DISPERBYK-2001, DISPERBYK-2050, DISPERBYK-2150 (, BYK-Chemie Japan ), solsperse 24000GR, solsperse 32000, solsperse 26000, solsperse 13240, solsperse 13940, solsperse 33500, </xnotran> Solsperse 38500, solsperse71000 (Rabotun, japan), and the like.
The light diffusing particles may be in various shapes such as spherical, filament, and amorphous shapes. However, when particles having a small particle shape and a small directionality (for example, spherical particles, regular tetrahedral particles, or the like) are used as the light diffusing particles, the particles are preferable in terms of further improving the uniformity, fluidity, and light diffusion of the ink composition containing the light emitting particles.
The average particle diameter (volume average diameter) of the light diffusing particles in the light emitting particle-containing ink composition is preferably 0.05 μm or more, 0.2 μm or more, and 0.3 μm or more, from the viewpoint of further improving the effect of reducing light leakage. The average particle diameter (volume average diameter) of the light diffusing particles in the ink composition containing the light emitting particles is preferably 1.0 μm or less, 0.6 μm or less, and 0.4 μm or less from the viewpoint of excellent storage stability and ejection stability of the ink. The average particle diameter (volume average diameter) of the light diffusing particles in the ink composition containing the luminescent particles is preferably 0.05 to 1.0. Mu.m, 0.05 to 0.6. Mu.m, 0.05 to 0.4. Mu.m, 0.2 to 1.0. Mu.m, 0.2 to 0.6. Mu.m, 0.2 to 0.4. Mu.m, 0.3 to 1.0. Mu.m, 0.3 to 0.6. Mu.m, or 0.3 to 0.4. Mu.m. From the viewpoint of easily obtaining such an average particle diameter (volume average diameter), the average particle diameter (volume average diameter) of the light diffusing particles to be used is preferably 50nm or more and 1000nm or less. The average particle diameter (volume average diameter) of the light diffusion particles in the ink composition containing the light emitting particles can be obtained by measuring with a dynamic light diffusion Nanotrac particle size distribution meter and calculating the volume average diameter. The average particle diameter (volume average diameter) of the light diffusion particles to be used can be obtained by measuring the particle diameter of each particle by a transmission electron microscope or a scanning electron microscope and calculating the volume average diameter, for example.
For the dispersion preparation of the light diffusing particles into the above particle size range, for example, a ball mill, a sand mill, an attritor, a roll mill, a stirrer, a Henschel Mixer, a colloid mill, an ultrasonic homogenizer, a bead mill, a wet jet mill, a paint shaker, or the like can be used.
The content of the light diffusing particles is preferably 0.1 mass% or more, 1 mass% or more, 5 mass% or more, 7 mass% or more, 10 mass% or more, or 12 mass% or more based on the mass of the nonvolatile component of the ink composition containing the light emitting particles, from the viewpoint of further improving the effect of reducing light leakage. The content of the light diffusing particles is preferably 60 mass% or less, 50 mass% or less, 40 mass% or less, 30 mass% or less, 25 mass% or less, 20 mass% or less, and 15 mass% or less, based on the mass of the nonvolatile component of the ink composition containing the light emitting particles, from the viewpoint of more excellent effect of reducing light leakage and excellent ejection stability. In the present embodiment, since the ink composition containing the light-emitting particles contains the polymer dispersant, the light-diffusing particles can be dispersed well even when the content of the light-diffusing particles is within the above range.
The mass ratio of the content of the light diffusing particles to the content of the light emitting particles 90 (light diffusing particles/luminescent nanocrystal-containing nanoparticles) is preferably 0.1 or more, 0.2 or more, or 0.5 or more, from the viewpoint of further improving the effect of reducing light leakage. From the viewpoint of more excellent effect of reducing light leakage and excellent continuous ejection property at the time of inkjet printing, the mass ratio (light-diffusing particles/nanoparticles containing light-emitting nanocrystals) is preferably 5.0 or less, 2.0 or less, and 1.5 or less. The reduction of light leakage by the light diffusion particles is considered to be based on the following mechanism. That is, when there are no light diffusion particles, it is considered that the backlight passes through the pixel portion substantially linearly, and the light emission particles 90 have less chance of being absorbed. On the other hand, if the light diffusion particles and the light emitting particles 90 are present in the same pixel portion, the backlight scatters in all directions in the pixel portion, and the light emitting particles 90 can receive light, and thus the light absorption amount of the pixel portion increases even if the same backlight is used. As a result, it is considered that light leakage can be prevented by such a mechanism.
1-6 polymer dispersant
The ink composition of the present invention may further contain a polymeric dispersant, or may contain both the light-diffusing particles and the polymeric dispersant. The polymer dispersant may be one having a functional group having affinity for the luminescent nanocrystal-containing nanoparticles and the light diffusing particles, and has a function of dispersing the luminescent nanocrystal-containing nanoparticles and the light diffusing particles. Further, the polymer dispersant is more preferably a functional group having affinity for the light diffusion particles, and is more preferably a function of dispersing the light diffusion particles. The polymer dispersant also contributes to the dispersion stability of the light-emitting particles.
The polymeric dispersant may be a polymer (homopolymer) of a single monomer or a copolymer (copolymer) of a plurality of monomers. The polymeric dispersant may be any of a random copolymer, a block copolymer, and a graft copolymer. When the polymeric dispersant is a graft copolymer, either a comb-shaped graft copolymer or a star-shaped graft copolymer can be used. Examples of the polymeric dispersant include: and polyamines such as acrylic resins, polyester resins, polyurethane resins, polyamide resins, polyethers, phenol resins, silicone resins, polyurea resins, amino resins, polyethyleneimine, and polyallylamine, epoxy resins, and polyimides.
The polymer dispersant is particularly preferably a block copolymer. The block copolymer applied to the high molecular dispersing agent can bring the following effects: by forming the block copolymer with a hydrophilic region and a pigment-adsorbing region, high dispersibility can be obtained, and dispersibility more excellent than that of a random copolymer and a cross copolymer can be obtained.
Specifically, in the random copolymer and the like, the probability that the monomers constituting the copolymer are stably arranged in the copolymer stereoscopically or electrically during the formation of the polymer becomes high. The portion (molecule) in which the monomer is stably arranged is sterically or electrically stable, and therefore, adsorption onto the pigment surface is often inhibited. In contrast, in the block copolymer type polymer dispersant in which the molecular arrangement is controlled, a portion that prevents adsorption of the dispersant to the pigment can be disposed at a position distant from the adsorption portion between the pigment and the dispersant. That is, it is presumed that by disposing a portion most suitable for adsorption in the adsorption portion between the pigment and the dispersant and a portion suitable for this in a portion requiring solvent affinity, in particular, in the dispersion of the inkjet ink containing a system of a pigment having a small crystal size, good dispersibility can be achieved by the molecular arrangement of the block copolymer.
The polymer dispersant of the present invention is not limited as long as it has the above-mentioned characteristics, and a block copolymer synthesized using a known ethylenically unsaturated monomer can be used.
Styrene and styrene derivatives, such as alpha-methylstyrene or vinyltoluene; vinyl esters of carboxylic acids, such as vinyl acetate, vinyl propionate; a vinyl halide; ethylenically unsaturated monocarboxylic and dicarboxylic acids, for example, acrylic acid, methacrylic acid, itaconic acid, maleic acid or fumaric acid, and monoalkyl esters of the above dicarboxylic acids and alkanols (preferably having 1 to 4 carbon atoms), and derivatives of the above monoalkyl esters, and N-substituted derivatives, aryl esters, and derivatives thereof; amides of unsaturated carboxylic acids, such as acrylamide, methacrylamide, N-methylolacrylamide or methacrylamide, N-alkylacrylamides; vinyl monomers containing sulfonic acid groups and ammonium or alkali metal salts thereof, such as vinylsulfonic acid, vinylbenzenesulfonic acid, α -acrylamidomethylpropanesulfonic acid, 2-sulfonated ethylene methacrylate; amides of vinylamines, such as vinylformamide, vinylacetamide; unsaturated vinyl monomers containing a secondary, tertiary or quaternary amino group or a nitrogen-containing heterocyclic group, such as vinylpyridine, vinylimidazole, aminoalkyl (meth) acrylate, aminoalkyl (meth) acrylamide, dimethylaminoethyl acrylate or methacrylate, di-tert-butylaminoethyl acrylate or methacrylate, or dimethylamino methacrylamide or methacrylamide; zwitterionic monomers such as sulfopropyl (dimethyl) aminopropyl acrylate; dienes such as butadiene, isoprene, chloroprene; (meth) acrylic acid esters; vinyl nitriles; vinylphosphonic acid and derivatives thereof.
The block copolymer can be synthesized by using such an ethylenically unsaturated monomer according to a known method, for example, a synthesis method such as Japanese patent application laid-open Nos. 2005-60669 and 2007-314617.
Among these, a (meth) acrylic block copolymer is preferably used, and can be synthesized, for example, by the following known methods, which are described in Japanese patent laid-open No. 60-89452; japanese patent laid-open publication No. 9-62002; lutz, p. Massonetal, ym. Bull.12,79 (1984); anderson, g.d.andrewstein, macromolecules,14,1601 (1981); K.Hatada, K.Ute, et al, polym.J.17,977 (1985); K.Hatada, K.Ute, et al, polym.J.18,1037 (1986); right-handed Haoyi, hazu-tanzang, macromolecule processing, 36,366 (1987); dongcun Minyan, zebenguang Men, high molecular corpus, 46,189 (1989); m.kuroki, t.aida, j.am.chem.sic,109,4737 (1987); zuozhuangsan, shanghanxianping, organic synthetic chemistry, 43,300 (1985); sogoh, w.r.hertlertel, macromolecules,20,1473 (1987); matyaszewskiet al, chem.Rev.2001,101,2921-2990, and the like.
The polymeric dispersant used in the present invention has a basic polar group, and examples of the basic functional group include: primary, secondary and tertiary amino groups, ammonium groups, imino groups, and nitrogen-containing heterocyclic groups of pyridine, pyrimidine, pyrazine, imidazole and triazole. The amine value of the polymer dispersant is preferably 6 to 90mgKOH/g, more preferably 7 to 70mgKOH/g, and still more preferably 8 to 50mgKOH/g. If the amine value of the polymer dispersant is less than 6mgKOH/g, the adsorption property of the polymer dispersant to the light-diffusing particles is low, and if the amine value is more than 90mgKOH/g, the polarity is increased, which easily causes aggregation and deterioration of storage property, and the dispersibility of the light-emitting particles is also deteriorated by the influence thereof.
The amine value of the polymeric dispersant can be measured in the following manner. Dissolving a polymeric dispersant xg and 1mL of bromophenol blue reagent in a solvent prepared by mixing toluene and ethanol in a volume ratio of 1:1, and titrating the mixture with 0.5mol/L hydrochloric acid until the sample solution turns green, and calculating the amine value by the following equation.
Amine value = y/x × 28.05
In the formula, y represents the titration amount (mL) of 0.5mol/L hydrochloric acid required for titration, and x represents the mass (g) of the polymer dispersant.
The polymer dispersant of the present invention is more preferably a block copolymer having a nitrogen-containing aromatic heterocycle or a salt thereof or an aromatic amine (for example, aniline, methoxyaniline, p-toluidine, α -naphthylamine, m-phenylenediamine, 1, 8-diaminonaphthalene, benzylamine, N-methylaniline, N-methylbenzylamine, or the like) in a part of the structure thereof in addition to the above-mentioned characteristics of the amine value. When a part of the structure of the block copolymer has an aromatic group, it is presumed that steric hindrance due to a bulky structure is easily obtained in addition to the acid-base interaction, and dispersibility is improved. Examples of the nitrogen-containing aromatic heterocycle include: five-membered aromatic heterocycles such as pyrrole, imidazole, pyrazole, oxazole, isoxazole, thiazole and isothiazole; six-membered aromatic heterocyclic rings such as pyridine, pyrimidine, pyridazine, pyrazine and triazine; polycyclic aromatic heterocycles such as quinoline, isoquinoline, quinazoline, phthalazine, pteridine, benzodiazepine, indole, benzimidazole, purine, acridine, phenoxazine, phenothiazine and the like, or salts thereof (for example, inorganic salts, organic salts and the like) and the like, each of which may have a substituent.
Specific examples of the polymeric dispersant having a basic functional group of a tertiary amino group or a nitrogen-containing heterocycle include: "DISPERBYK-164" (amine value: 18 mgKOH/g), "DISPERBYK-167" (amine value: 13 mgKOH/g), "DISPERBYK-2164" (amine value: 23 mgKOH/g), "BYK-LP N6919" (amine value: 120 mgKOH/g), "BYK-LP N21116" (amine value: 29 mgKOH/g) (above, manufactured by BYK-Chemie Japan K.K.), "Solsperse 20000" (amine value: 32 mgKOH/g) (manufactured by Nippon Luobo corporation), "Efka PX4320" (amine value: 28 mgKOH/g), "Dispex Ultratra PX 85" (amine value: 20 mgKOH/g), "Efka PX4701 (amine value: 40 mgKOH/g)" (manufactured by BASF Japan K..
The polymeric dispersant may have other functional groups in addition to the basic functional group. Examples of the other functional group include 1 or more functional groups selected from the group consisting of an acidic functional group and a nonionic functional group. These functional groups preferably have an affinity for the light diffusing particles. The acidic functional group has a dissociative proton and can be neutralized with a base such as an amine or hydroxide ion.
As the acidic functional group, there can be mentioned: carboxyl (-COOH), sulfo (-SO) 3 H) Sulfuric acid radical (-OSO) 3 H) Phosphonic acid group (-PO (OH) 3 ) Phosphate group (-OPO (OH) 3 ) Phosphinic acid groups (-PO (OH) -), mercapto groups (-SH).
Examples of the nonionic functional group include: hydroxyl, ether, thioether, sulfinyl (-SO-), sulfonyl (-SO-) 2 -), carbonyl, formyl, ester, carbonate, amide, carbamoyl, ureido, thioamido, thioureido, aminosulfonyl, cyano, alkenyl, alkynyl, phosphinoxide, phosphinothioyl.
The polymeric dispersant having an acidic functional group in addition to a basic functional group has an acid value in addition to an amine value. The acid value of the polymeric dispersant having an acidic functional group is preferably 0 to 50mgKOH/g, more preferably 0 to 40mgKOH/g, still more preferably 0 to 30mgKOH/g, and is 0 to 20mgKOH/g or less. When the acid value is 50mgKOH/g or less, the storage stability of the pixel portion (cured product of the ink composition) is not easily lowered.
The acid value of the polymeric dispersant can be measured in the following manner. Dissolving a macromolecular dispersant pg and a phenolphthalein reagent 1mL in a solvent prepared by mixing toluene and ethanol in a volume ratio of 1:1 to 50mL of a mixed solution, a potassium hydroxide solution (prepared by dissolving 7.0g of potassium hydroxide in 5.0mL of distilled water and adding 95vol% ethanol to 1000 mL) was titrated with 0.1mol/L ethanol to obtain a sample solution having a pale red color, and the acid value was calculated by the following equation.
Acid value = qxr × 5.611/p
In the formula, q represents the titration amount (mL) of 0.1mol/L ethanol potassium hydroxide solution required for titration, r represents the titer of 0.1mol/L ethanol potassium hydroxide solution required for titration, and p represents the mass (g) of the polymeric dispersant.
Examples of the polymeric dispersant having an amine value and an acid value include: <xnotran> "DISPERBYK-142" (:43mgKOH/g, :46 mgKOH/g), "DISPERBYK-145" (:71mgKOH/g, :76 mgKOH/g), "DISPERBYK-2001" (:29mgKOH/g, :19 mgKOH/g), "DISPERBYK-2025" (:37mgKOH/g, :38 mgKOH/g), "DISPERBYK-9076" (:44mgKOH/g, :38 mgKOH/g) (, BYK-Chemie Japan ), "Solsperse 24000GR" (:42mgKOH/g, :25 mgKOH/g), "Solsperse 32000" (:31mgKOH/g, :15 mgKOH/g), "Solsperse 33000" (:43mgKOH/g, :26 mgKOH/g), "Solsperse 34750", "Solsperse 35100" (:14mgKOH/g, :6 mgKOH/g), "Solsperse 35200" (:14mgKOH/g, :6 mgKOH/g), "Solsperse 37500" (:11mgKOH/g, :5 mgKOH/g), "Solsperse 39000" (:29mgKOH/g, :16 mgKOH/g), ( ), "Ajisper PB821" (:10mgKOH/g, :17 mgKOH/g), "Ajisper PB822" (:17mgKOH/g, :14 mgKOH/g), "Ajisper PB824" (:17mgKOH/g, :21 mgKOH/g), "Ajisper PB881" (:17mgKOH/g, :17 mgKOH/g) (, </xnotran> Ajinomoto Fine-Techno corporation), and the like.
The polymer dispersant of the present invention is more preferably an acrylic block copolymer having a partial structure represented by the following general formulae (a) to (c).
Figure BDA0004092365490000661
(in the general formula (b), R b1 Represents a hydrogen atom or a methyl group, R b2 Represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms)
Figure BDA0004092365490000671
(in the general formula (c), R c1 Represents a hydrogen atom or a methyl group, R c2 Represents an alkylene group having 2 to 3 carbon atoms, m represents an integer of 5 to 15, R c3 Represents an alkyl group having 1 to 25 carbon atoms, a phenyl group, or a phenyl group substituted with an alkyl group having 1 to 18 carbon atoms).
As the monomer providing the structural unit represented by the above general formula (a), specifically, 2-vinylpyridine or pyridinium ion, 4-vinylpyridine or pyridinium ion is preferable, and 2-vinylpyridine and 4-vinylpyridine are more preferable.
In the above general formula (b), R b1 Preferably an alkyl group having 2 to 8 carbon atoms, more preferably an alkyl group having 4 to 8 carbon atoms, and still more preferably an n-butyl group.
In the general formula (c), m is preferably an integer of 7 to 12, R c3 Preferably an alkyl group having 1 to 4 carbon atoms.
The polymer dispersant containing the structural units (a) to (c) has high adsorption of pyridine contained in the constituent monomers of the dispersant to the light-diffusing particles, and therefore the surface of the light-diffusing particles is easily covered with the dispersant during dispersion, and the light-diffusing particles can be dispersed in the ink composition by electrostatic repulsion and/or steric repulsion between the dispersants. The polymer dispersant is preferably bonded to the surface of the light-diffusing particles and adsorbed to the light-diffusing particles, but may be bonded to the surface of the light-emitting particles and adsorbed to the light-emitting particles, or may be released in the ink composition.
In the polymer dispersant containing the above-mentioned structural units (a) to (c), the structural unit (c) of the block copolymer has excellent affinity for the photopolymerizable compound, and the structural units (a) and (c) containing the copolymer can achieve both excellent dispersibility of the light diffusing particles and affinity for the photopolymerizable compound.
The copolymer having the monomer units represented by the above-mentioned structural units (a) to (c) is not particularly limited, and can be suitably synthesized by living radical polymerization using a nitroxide initiator (NMP initiator).
When the copolymer has monomer units represented by the structural units (a), (b), and (c) in the polymer dispersant, the structural unit (a) is preferably 5 to 50 mol%, and more preferably 10 to 30 mol%, with respect to the content of the monomer units in the polymer dispersant, assuming that the total of all the monomer units constituting the polymer dispersant is 100 mol%. When the amount is within the above range, the storage stability of the ink and the dispersibility of the light diffusing particles are further excellent.
In the above-mentioned polymer dispersant, the molar ratio of the content of the monomer unit represented by formula (b) to the content of the monomer unit represented by formula (c) is preferably 1: 2-2: 1, more preferably 1: 1.5-1.5: 1.
The weight average molecular weight (Mw) of the polymer dispersant is preferably 10,000 to 70,000, more preferably 12,000 to 30,000, even more preferably 13,000 to 25,000, and particularly preferably 15,000 to 20,000, from the viewpoint of improving the light emission characteristics of the ink composition by making the light diffusion particles well dispersed and further improving the effect of reducing light leakage, and from the viewpoint of making the viscosity of the inkjet ink a viscosity that enables ejection and is suitable for stable ejection. In the present specification, the weight average molecular weight is a weight average molecular weight in terms of polystyrene measured by GPC (Gel Permeation Chromatography).
The content of the polymer dispersant in the ink composition is preferably 0.5 to 50% by mass, more preferably 2 to 30% by mass, and even more preferably 5 to 10% by mass, based on 100% by mass of the light-diffusing particles, from the viewpoints of dispersibility of the light-diffusing particles and stability against heat and humidity of the pixel portion (dispersion liquid or cured product of the ink composition).
Specific examples of the polymer dispersant having a partial structure represented by the general formulae (a) to (c) include: "Efka PX4320" (amine value: 28 mgKOH/g), "Dispex Ultra PX4585" (amine value: 20 mgKOH/g), "Efka PX4701" (amine value: 40 mgKOH/g) (manufactured by BASF Japan K.K.) and the like.
1-7. Other ingredients
The ink composition may further contain components other than the above components within a range not to inhibit the effects of the present invention.
1-7-1. Sensitizing agent
As the sensitizer, amines which do not undergo addition reaction with the photopolymerizable compound can be used. Examples of sensitizers include: trimethylamine, methyldimethanolamine, triethanolamine, p-diethylaminoacetophenone, ethyl p-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, N-dimethylbenzylamine, 4' -bis (diethylamino) benzophenone, and the like.
1-7-2. Solvent
The ink composition may further contain, for example, a solvent. Examples of the solvent include: cyclohexane, hexane, heptane, chloroform, toluene, octane, chlorobenzene, tetrahydronaphthalene, diphenyl ether, propylene glycol monomethyl ether acetate, butyl carbitol acetate, or mixtures thereof, and the like. The boiling point of the solvent is preferably 180 ℃ or higher from the viewpoint of continuous ejection stability of the inkjet ink. In addition, since the solvent needs to be removed from the ink composition before curing of the ink composition when forming the pixel portion, the boiling point of the solvent is preferably 300 ℃ or less from the viewpoint of easy removal of the solvent. However, in the ink composition of the present embodiment, since the photopolymerizable compound also functions as a dispersion medium, the light diffusing particles and the light emitting particles can be dispersed without a solvent. In this case, there is an advantage that a step of removing the solvent by drying is not required when forming the pixel portion. When the ink composition contains a solvent, the content of the solvent is preferably 0 to 5% by mass or less based on the total mass of the ink composition (including the solvent).
1-7-3. Surfactant
The surfactant is not particularly limited, and is preferably a compound having good ink ejection properties and being capable of reducing film thickness unevenness when forming a thin film containing the light-emitting particles 91 and the light-emitting particles 90.
Examples of such surfactants include: anionic surfactants such as dialkyl sulfosuccinates, alkyl naphthalenesulfonates, and fatty acid salts, nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, and polyoxyethylene-polyoxypropylene block copolymers, cationic surfactants such as alkylamine salts and quaternary ammonium salts, and silicone or fluorine surfactants.
Specific examples of the silicone surfactant include: "KF-351A", "KF-352A", "KF-642", "X-22-4272" (manufactured by shin-Etsu chemical Co., ltd., "BYK-300", "BYK-302", "BYK-306", "BYK-307", "BYK-310", "BYK-313", "BYK-315N", "BYK-320", "BYK-322", "BYK-323", "BYK-325", "BYK-330", "BYK-331", "BYK-333", "BYK-342", "BYK-345", "BYK-347", "BYK-348", "BYK-349", "BYK-370", "BYK-377", "BYK-UV3500", "BYK-UV3510", "BYK-UV3530", "BYK-UV3570", "BYK-Silclean3700", "BYK-Silclean3720" (or more, BYK-Chemie Japan K.K.), "TEGO Rad2100", "TEGO Rad2011", "TEGO Rad2200N", "TEGO Rad2250", "TEGO Rad2300", "TEGO Rad2500", "TEGO Rad2600", "TEGO Rad2650", "TEGO Rad2700", "TEGO Flow425", "TEGO Glide410", "TEGO Glide432", "TEGO Glide440", "TEGO Glide450", "TEGO Glide ZG400", "TEGO Twin4000", "TEGO Twin4100", "TEGO Twin4200" (above, manufactured by Evonik Industries, U.S. "," DOWN SIL L-7001"," DOWNSIL L-7002"," SIL 57ADDTIVE "," DOW L-7064"," FZ-2110"," FZ-2105"," SIL 67 "(above, manufactured by Dow FLO Inc.)," Dow KL 400-SIL K401 "," SIL, "Polyflow KL-402", "Polyflow KL-403", and "Polyflow KL-404" (manufactured by Kyoho chemical Co., ltd.).
Specific examples of the fluorine-based surfactant include: "MEGAFAC F-114", "MEGAFAC F-251", "MEGAFAC F-281", "MEGAFAC F-410", "MEGAFAC F-430", "MEGAFAC F-444", "MEGAFAC F-472SF", "MEGAFAC F-477", "MEGAFAC F-510", "MEGAFAC F-511", "MEGAFAC F-552", "MEGAFAC F-553", "MEGAFAC F-554", "MEGAFAC F-555", "MEGAFAC F-556", "MEGAFAC F-557", "MEGAFAC F-558", "MEGAFAC F-559", "MEGAFAC F-560", "MEGAFAC F-561", "MEGAFAC F-562"; "MEGAFAC F-563", "MEGAFAC F-565", "MEGAFAC F-567", "MEGAFAC F-568", "MEGAFAC F-569", "MEGAFAC F-570", "MEGAFAC F-571", "MEGAFAC R-40", "MEGAFAC R-41", "MEGAFAC R-43", "MEGAFAC R-94", "MEGAFAC RS-72-K", "MEGAFAC RS-75", "MEGAFAC RS-76-E", "MEGAFAC RS-76-NS", "MEGAFAC RS-90", "MEGAFAC EXP.TF-1367", "MEGAFAC EXP.TF1437", "MEGAFAC EXP.TF1537", "MEGAFAC EXP.TF-2066" (or more, DIC corporation) and the like.
Other specific examples of the fluorine-based surfactant include: "FTERGENT 100", "FTERGENT 100C", "FTERGENT 110", "FTERGENT 150CH", "FTERGENT 100A-K", "FTERGENT 300", "FTERGENT 310", "FTERGENT 320", "FTERGENT 400SW", "FTERGENT 251", "FTERGENT 215M", "FTERGENT 212M", "FTERGENT 215M", "FTERGENT 250", "FTERGENT 222F", "FTERGENT 212D", "FTX-218", "FTERGENT 209F", "FTERGENT 245F", "FTERGENT 208G", "FTERGENT 240G", "FTERGENT 212P", "FTERGENT 220P", "FTERGENT 228P", "DFX-18", "FTERGENT 601", "FTERGEGEDAO 602A", "GENT 650", "FTERGENT FM-750", "FTX-FLEXIFERGENT 4432", "FTERGENT GFR-FLEXOFS 730", and F32 of "FTERGENT GFR-FLOERGENT 250", "FTERGENT 32", and "FTERGENT GFR 32, and" of "FLOERGENT GFR 32, and" FLOERGENT CO.
The amount of the surfactant added is preferably 0.005 to 2% by mass, and more preferably 0.01 to 0.5% by mass, based on the total amount of the photopolymerizable compound contained in the light-emitting particle-containing ink composition.
1-7-4. Chain transfer agent
The chain transfer agent is a component used for the purpose of further improving the adhesion between the ink composition containing the luminescent particles and the substrate. Examples of the chain transfer agent include: aromatic hydrocarbons; halogenated hydrocarbons such as chloroform, carbon tetrachloride, carbon tetrabromide, bromotrichloromethane; thiol compounds such as octyl thiol, n-butyl thiol, n-pentyl thiol, n-hexadecylthiol, n-tetradecylthiol, n-dodecyl thiol, tert-tetradecylthiol, and tert-dodecyl thiol; mercaptan compounds such as hexane dithiol, decane dithiol, 1, 4-butanediol bisthiopropionate, 1, 4-butanediol bisthioglycolate, ethylene glycol bisthiopropionate, trimethylolpropane trimercaptoacetate, trimethylolpropane trithiopropionate, trimethylolpropane tris (3-mercaptobutyrate), pentaerythritol tetramercaptoacetate, pentaerythritol tetrathiopropionate, tris (2-hydroxyethyl) isocyanurate of trimercaptopropionic acid, 1, 4-dimethylmercaptobenzene, 2,4, 6-trimercaptos-triazine, and 2- (N, N-dibutylamino) -4, 6-dimercaptos-triazine; thioether compounds such as dimethyl xanthogen disulfide, diethyl xanthogen disulfide, diisopropyl xanthogen disulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, and tetrabutylthiuram disulfide; n, N-dimethylaniline, N-divinylaniline, pentaphenylethane, alpha-methylstyrene dimer, acrolein, allyl alcohol, terpinolene, alpha-terpinene, gamma-terpinene, dipentene, etc., but 2, 4-diphenyl-4-methyl-1-pentene, thiol compounds are preferable.
Specific examples of the chain transfer agent include compounds represented by the following general formulae (9-1) to (9-12).
Figure BDA0004092365490000721
In the formula, R 95 Represents an alkyl group having 2 to 18 carbon atoms, which may be linear or branched, wherein at least 1 methylene group in the alkyl group may be substituted by an oxygen atom, a sulfur atom, -CO-, -OCO-, -COO-, or-CH = CH-, without directly bonding an oxygen atom and a sulfur atom to each other.
R 96 Represents an alkylene group having 2 to 18 carbon atoms, wherein 1 or more methylene groups in the alkylene group may be substituted with oxygen atoms or sulfur atoms in the case where the oxygen atoms and sulfur atoms are not directly bonded to each other a sulfur atom, -CO-, -OCO-, -COO-or-CH = CH-.
The amount of the chain transfer agent added is preferably 0.1 to 10% by mass, and more preferably 1.0 to 5% by mass, based on the total amount of the photopolymerizable compound contained in the light-emitting particle-containing ink composition.
1-7-5. Light stabilizer
The ink composition of the present invention may also contain a light stabilizer having a structure represented by the following formula (1). The light stabilizer may also be a light stabilizer having 1 or 2 or more hindered amino groups. The ink composition may use only 1 kind of light stabilizer, or may use 2 or more kinds.
Figure BDA0004092365490000731
(in the formula (1), R 1 Represents a hydrogen atom or a substituent, represents a bond)
As R 1 More specifically, hydrogen atom, alkyl group, alkoxy group and the like are mentioned, among which alkyl group or alkoxy group is preferable, and methyl group is more preferable.
* Represents a bond, and may be, for example, a bonding site with a carbon atom, a nitrogen atom, or an oxygen atom.
The light stabilizer may be a compound further having a 1,3, 5-triazine ring which may have a substituent. For example, the structure represented by formula (1) may be bonded to the 1,3, 5-triazine ring directly or via another atom (e.g., nitrogen atom).
The light stabilizer may be used, for example, in the form of a liquid at 20 ℃ or a solid at 20 ℃. However, considering that the cured product of the ink composition may be heated to, for example, about 50 ℃ with light irradiation, the melting point of the light stabilizer is preferably high, and is preferably 70 ℃ or higher, 80 ℃ or higher, or 85 ℃ or higher. When the light stabilizer having a melting point of 70 ℃ or higher is used, the light stabilizer does not liquefy even when a cured product of the ink composition is heated to a high temperature of about 50 ℃, and thus the light stabilizer can be prevented from bleeding out of the cured product to the surface of the cured product (bleed-out resistance). On the other hand, the melting point of the light stabilizer is preferably 180 ℃ or lower in view of solubility in the ink composition.
The molecular weight (or molar mass) or mass average molecular weight of the light stabilizer may be 1000 or more. In the present specification, the "mass average molecular weight" may adopt a value measured using Gel Permeation Chromatography (GPC) using polystyrene as a standard substance. When the molecular weight or the mass average molecular weight is within the above range, the melting point becomes high, and therefore bleeding resistance under a high temperature environment can be reliably obtained, and light resistance becomes further excellent.
It is considered that the light stabilizer captures radicals at the nitrogen atom site in the general formula (1), and the more the equivalent of the functional group represented by the following formula, which represents the proportion of the site represented by the general formula (1) in the molecule of the light stabilizer, is, the more excellent the light resistance is, in order to efficiently capture radicals generated in the light conversion layer.
Functional group equivalent = molecular weight of light stabilizer/number of sites represented by general formula (1) in light stabilizer
The functional group equivalent is preferably 200 to 400, more preferably 250 to 370, from the viewpoint of excellent radical trapping properties and solubility.
The light stabilizer is preferably a compound represented by the following formulae (1 a) to (1 e), for example. The light stabilizer is more preferably a compound represented by the following formula (1 a) or the following formula (1 b) from the viewpoint of further excellent curability and further excellent light resistance at high temperatures.
Figure BDA0004092365490000741
(in the formula (1 a), n represents an integer of 1 to 15.)
Figure BDA0004092365490000742
(in the formula (1 b), n represents an integer of 1 to 15.)
Figure BDA0004092365490000743
Figure BDA0004092365490000751
Examples of commercially available light stabilizers include: TINUVIN NOR371 (melting point: 91-104 ℃, mass average molecular weight: 2800-4000, functional group equivalent: 350, manufactured by BASF Japan K.K.), adekastab LA-63P (melting point: 85-105 ℃, molecular weight: about 2000, functional group equivalent: 276, manufactured by BASF Japan K.K.), TINUVIN123 (melting point < 20 ℃ (liquid), molecular weight: 737, functional group equivalent: 368, manufactured by BASF Japan K.K.) having the structure represented by formula (1 c), adekastab LA-81 (melting point < 20 ℃ (liquid), molecular weight 681, functional group equivalent: 340, manufactured by ADEKA K.K.) having the structure represented by formula (1 d), adekastab LA-52 (melting point < 20 ℃) (melting point < liquid), molecular weight: 847, functional group equivalent 212, manufactured by BASF Japan K.K.K., 843, manufactured by BASF Japan K.K., 843) having the structure represented by formula (1 e).
From the viewpoint of further excellent light resistance at high temperatures, the light stabilizer is preferably 0.1 to 5.0% by mass, more preferably 0.2 to 3.0% by mass, and particularly preferably 2.0 to 0.3% by mass or more, based on the total mass of the ink composition.
1-8 viscosity of ink composition
The viscosity of the ink composition of the present invention is preferably 2mPa · s or more, more preferably 5mPa · s or more, and even more preferably 7mPa · s or more, from the viewpoint of ejection stability at the time of inkjet printing, for example. The viscosity of the ink composition is preferably 20mPa · s or less, more preferably 15mPa · s or less, and further preferably 12mPa · s or less. When the viscosity of the ink composition is 2mPa · s or more, the meniscus shape of the ink composition at the tip of the ink ejection hole of the head is stable, and therefore ejection control of the ink composition (for example, control of the ejection amount and ejection timing) becomes easy. On the other hand, when the viscosity is 20mPa · s or less, the ink composition can be smoothly ejected from the ink ejection hole. The viscosity of the ink composition is preferably 2 to 20 mPas, more preferably 5 to 15 mPas, and still more preferably 7 to 12 mPas. The viscosity of the ink composition is measured, for example, by an E-type viscometer. The viscosity of the ink composition can be adjusted to a desired range by changing, for example, a photopolymerizable compound, a photopolymerization initiator, and the like.
1-9 surface tension of ink composition
The surface tension of the ink composition of the present invention is preferably a surface tension suitable for an ink jet system, and specifically, is preferably in the range of 20 to 40mN/m, and more preferably 25 to 35mN/m. By setting the surface tension to this range, the occurrence of flight drift can be suppressed. The flying offset means that when the ink composition is ejected from the ink ejection hole, the landing position of the ink composition is offset by 30 μm or more from the target position. When the surface tension is 40mN/m or less, since the meniscus shape at the tip of the ink ejection hole is stable, ejection control of the ink composition (for example, control of the ejection amount and ejection timing) becomes easy. On the other hand, when the surface tension is 20mN/m or less, the occurrence of flight drift can be suppressed. That is, the following does not occur: the ink composition is not accurately landed on a pixel portion formation region to be landed, and thus, the ink composition is insufficiently filled in the pixel portion, or the ink composition is landed on a pixel portion formation region (or a pixel portion) adjacent to the pixel portion formation region to be landed, and thus, the color reproducibility is lowered. The surface tension of the ink composition can be adjusted to a desired range by using the above-mentioned silicone surfactant, fluorine surfactant, and the like in combination.
1-10. Preparation method of ink composition
The ink composition of the present invention, for example, an active energy ray-curable ink composition can be prepared by blending the above components, and can be used as an ink for inkjet. In a specific method for producing the ink composition for inkjet, the light-emitting particles 90 or 91 are synthesized in an organic solvent, the organic solvent is removed from the separated precipitate by centrifugal separation, and then the organic solvent is dispersed in a photopolymerizable compound. The dispersion of the light-emitting particles 90 or 91 can be performed by using a dispersing machine such as a ball mill, a sand mill, a bead mill, a three-roll mill, a paint conditioner, an attritor, a dispersion mixer, or an ultrasonic wave. Further, the photopolymerization initiator and the antioxidant can be added to the dispersion liquid and stirred and mixed to prepare the aqueous dispersion. In addition, when the light diffusion particles are used, they can be prepared by: the light-diffusing particles are mixed with a polymeric dispersant, a slurry dispersed in the photopolymerizable compound is separately prepared by a bead mill, and the photopolymerizable compound and a photopolymerization initiator are mixed together with the light-emitting particles.
Next, a method for producing the ink composition of the present invention will be specifically described. The ink composition can be obtained by, for example, mixing the components of the ink composition and performing dispersion treatment. The dispersion can be obtained by preparing a dispersion in which the constituent components are individually mixed and dispersed as necessary, and mixing the respective dispersions. Hereinafter, a method for producing an ink composition further containing light diffusing particles and a polymeric dispersant will be described as an example of a method for producing an ink composition.
In the step of preparing the dispersion liquid of the light diffusing particles, the polymeric dispersant and the photopolymerizable compound are mixed and dispersed to prepare the dispersion liquid of the light diffusing particles. The mixing and dispersing treatment can be carried out using a dispersing apparatus such as a bead mill, a paint conditioner, a planetary mixer, or the like. According to the above method, a bead mill or a paint conditioner is preferably used from the viewpoint that the dispersibility of the light diffusion particles becomes good and the average particle diameter of the light diffusion particles can be easily adjusted to a desired range.
The method for producing an ink composition may further comprise, before the 2 nd step, the steps of: a dispersion of light-emitting particles containing light-emitting particles and a photopolymerizable compound is prepared. In this case, in the 2 nd step, a dispersion of the light diffusing particles, a dispersion of the light emitting particles, a photopolymerization initiator, and an antioxidant are mixed. According to this method, the light-emitting particles can be sufficiently dispersed. Therefore, light leakage in the pixel portion can be reduced, and an ink composition excellent in ejection stability can be easily obtained. In the step of preparing the dispersion liquid of the light-emitting particles, mixing and dispersing treatment of the light-emitting particles and the photopolymerizable compound may be performed using a dispersing apparatus similar to the step of preparing the dispersion liquid of the light-diffusing particles.
When the ink composition of the present embodiment is used as an ink composition for an ink jet system, the ink composition is preferably applied to a piezoelectric ink jet system ink jet recording apparatus using a mechanical discharge mechanism using a piezoelectric element. In the piezoelectric ink jet system, since the ink composition is not instantaneously exposed to a high temperature at the time of ejection, and the light-emitting particles are less likely to be altered, a color filter pixel portion (light conversion layer) having desired light emission characteristics can be obtained.
Although one embodiment of the ink composition for color filters has been described above, the ink composition of the above embodiment can be used not only in the inkjet method but also in the photolithography method, for example. In this case, the ink composition contains an alkali-soluble resin as a binder polymer.
When the ink composition is used by photolithography, the ink composition is first applied to a substrate, and when the ink composition contains a solvent, the ink composition is further dried to form a coating film. The coating film thus obtained is soluble in an alkali developing solution, and is patterned by treatment with the alkali developing solution. In this case, the alkali developing solution is mostly an aqueous solution from the viewpoint of ease of waste liquid treatment of the developing solution, and therefore a coating film of the ink composition is treated with the aqueous solution. On the other hand, in the case of an ink composition using light-emitting particles (quantum dots or the like), the light-emitting particles are unstable to water, and the light-emitting property (e.g., fluorescence) is impaired by moisture. Therefore, in this embodiment, an inkjet system that does not require processing with an alkali developing solution (aqueous solution) is preferable.
In addition, even when the ink composition is not treated with an alkali developing solution, if the ink composition is alkali-soluble, the coating film of the ink composition easily absorbs moisture in the atmosphere, and the luminescence (e.g., fluorescence) of the light-emitting particles (quantum dots, etc.) is impaired with the passage of time. From this viewpoint, in the present embodiment, the coating film of the ink composition is preferably alkali-insoluble. That is, the ink composition of the present embodiment is preferably an ink composition capable of forming an alkali-insoluble coating film. Such an ink composition can be obtained by using an alkali-insoluble photopolymerizable compound as the photopolymerizable compound. The term "the coating film of the ink composition is alkali-insoluble" means that the amount of the coating film of the ink composition dissolved in a 1 mass% potassium hydroxide aqueous solution at 25 ℃ is 30 mass% or less based on the total mass of the coating film of the ink composition. The amount of the dissolved ink in the coating film of the ink composition is preferably 10% by mass or less, and more preferably 3% by mass or less. The ink composition capable of forming an alkali-insoluble coating film can be confirmed by: the amount of the ink composition dissolved in a 1 μm thick coating film obtained by drying the ink composition at 80 ℃ for 3 minutes in the presence of a solvent was measured.
2. Example of Using ink composition containing luminescent particles
The ink composition containing the light-emitting particles can be cured by forming a coating film on a substrate by various methods such as an ink jet printer, a photolithography machine, and a spin coater and heating the coating film to obtain a cured product. The following description will be given by taking an example of a case where a color filter pixel portion including a light emitting element of a blue organic LED backlight is formed using an ink composition containing light emitting particles.
Fig. 3 is a cross-sectional view showing one embodiment of the light-emitting element of the present invention, and fig. 4 and 5 are schematic diagrams each showing a configuration of an active matrix circuit. In fig. 3, the sizes of the respective portions and the ratios thereof are exaggerated for convenience, and may be different from actual ones. The materials, dimensions, and the like shown below are examples, and the present invention is not limited to these, and can be appropriately modified within the scope not changing the gist of the present invention. Hereinafter, for convenience of description, the upper side of fig. 3 is referred to as "upper side" or "upper side", and the lower side is referred to as "lower side" or "lower side". In fig. 3, hatching of the display cross section is omitted in order to avoid complication of the drawing.
As shown in fig. 3, the light-emitting element 100 has a structure in which a lower substrate 1, an EL light source unit 200, a filling layer 10, a protective layer 11, a light-converting layer 12 that contains light-emitting particles 90 and functions as a light-emitting layer, and an upper substrate 13 are stacked in this order. The light-emitting particles 90 contained in the light conversion layer 12 may be polymer-coated light-emitting particles 90 or may be light-emitting particles 91 that are not coated with the polymer layer 92. The EL light source unit 200 includes in order: an anode 2, an EL layer 14 composed of a plurality of layers, a cathode 8, a polarizing plate not shown, and a sealing layer 9. The EL layer 14 includes a hole injection layer 3, a hole transport layer 4, a light emitting layer 5, an electron transport layer 6, and an electron injection layer 7, which are stacked in this order from the anode 2 side.
The light emitting element 100 is a photoluminescent element that absorbs and re-emits light emitted from the EL light source section 200 (EL layer 14) by the light conversion layer 12 or transmits the light, and is extracted to the outside from the upper substrate 13 side. At this time, the light is converted into light of a predetermined color by the light-emitting particles 90 contained in the light conversion layer 12. Hereinafter, each layer will be described in order.
< lower substrate 1 and upper substrate 13 >
The lower substrate 1 and the upper substrate 13 have a function of supporting and/or protecting each layer constituting the light emitting element 100. When the light emitting element 100 is of a top emission type, the upper substrate 13 is formed of a transparent substrate. On the other hand, when the light emitting element 100 is of a bottom emission type, the lower substrate 1 is formed of a transparent substrate. Here, the transparent substrate is a substrate that can transmit light having a wavelength in the visible light range, and includes transparent, colorless, transparent, colored, and translucent.
As the transparent substrate, for example, a transparent glass substrate such as quartz glass, pyrex (registered trademark) glass, or synthetic quartz plate, or a quartz substrate; a plastic substrate (resin substrate) composed of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyimide (PI), polycarbonate (PC), or the like; a metal substrate made of iron, stainless steel, aluminum, copper, or the like; a silicon substrate; gallium arsenide substrates, and the like. Among them, a glass substrate made of alkali-free glass containing no alkali component in the glass is preferably used. Specifically, "7059 Glass", "1737 Glass", "Eagle 200" and "Eagle XG" manufactured by Corning corporation, "AN100" manufactured by Asahi Glass company, "OA-10G" and "OA-11" manufactured by Nippon Electric Glass company are preferable. These are materials having a small thermal expansion coefficient and are excellent in dimensional stability and workability in high-temperature heat treatment. When flexibility is imparted to the light-emitting element 100, the lower substrate 1 and the upper substrate 13 are each selected from a plastic substrate (a substrate made of a polymer material as a main material) and a metal substrate having a small thickness.
The thicknesses of the lower substrate 1 and the upper substrate 13 are not particularly limited, and are preferably in the range of 100 to 1,000 μm, and more preferably in the range of 300 to 800 μm.
Depending on the usage of the light-emitting element 100, either or both of the lower substrate 1 and the upper substrate 13 may be omitted.
As shown in fig. 4, the lower substrate 1 includes: a signal line driving circuit C1 and a scanning line driving circuit C2 that control supply of current to the anode 2 constituting the pixel electrode PE shown in R, G, and B, a control circuit C3 that controls operations of these circuits, a plurality of signal lines 706 connected to the signal line driving circuit C1, and a plurality of scanning lines 707 connected to the scanning line driving circuit C2. In addition, in the vicinity of an intersection of each signal line 706 and each scanning line 707, as shown in fig. 5, a capacitor 701, a driving transistor 702, and a switching transistor 708 are provided.
In the capacitor 701, one electrode is connected to a gate electrode of the driving transistor 702, and the other electrode is connected to a source electrode of the driving transistor 702. In the driving transistor 702, a gate electrode is connected to one electrode of the capacitor 701, a source electrode is connected to the other electrode of the capacitor 701 and the power supply line 703 for supplying a driving current, and a drain electrode is connected to the anode 4 of the EL light source section 200.
In the switching transistor 708, a gate electrode is connected to the scanning line 707, a source electrode is connected to the signal line 706, and a drain electrode is connected to the gate electrode of the driving transistor 702. In the present embodiment, the common electrode 705 constitutes the cathode 8 of the EL light source unit 200. The driving transistor 702 and the switching transistor 708 may be formed of, for example, thin film transistors.
The scanning line driving circuit C2 supplies or blocks a scanning voltage corresponding to a scanning signal to the gate electrode of the switching transistor 708 via the scanning line 707, thereby turning on or off the switching transistor 708. Thereby, the scanning line driving circuit C2 adjusts the timing of writing the signal voltage in the signal line driving circuit C1. On the other hand, the signal line driving circuit C1 supplies or blocks a signal voltage corresponding to a video signal to the gate electrode of the driving transistor 702 via the signal line 706 and the switching transistor 708, thereby adjusting the amount of the signal current supplied to the EL light source section 200.
Therefore, a scanning voltage is supplied from the scanning line driving circuit C2 to the gate electrode of the switching transistor 708, and when the switching transistor 708 is turned on, a signal voltage is supplied from the signal line driving circuit C1 to the gate electrode of the switching transistor 708. At this time, the drain current corresponding to the signal voltage is supplied as a signal current from the power supply line 703 to the EL light source section 200. As a result, the EL light source section 200 emits light in accordance with the supplied signal current.
< EL light source section 200 >
[ Anode 2]
The anode 2 has a function of supplying holes from an external power source to the light-emitting layer 5. The constituent material (anode material) of the anode 2 is not particularly limited, and examples thereof include: metals such as gold (Au); halogenated metals such as copper iodide (CuI); indium Tin Oxide (ITO) and tin oxide (SnO) 2 ) And metal oxides such as zinc oxide (ZnO). These may be used alone in 1 kind, or in combination of 2 or more kinds.
The thickness of the anode 2 is not particularly limited, but is preferably in the range of 10 to 1,000nm, and more preferably in the range of 10 to 200 nm.
The anode 2 can be formed by a dry film formation method such as a vacuum deposition method or a sputtering method. At this time, the anode 2 having a predetermined pattern may be formed by photolithography or a method using a mask.
[ cathode 8]
The cathode 8 has a function of supplying electrons from an external power source toward the light-emitting layer 5. The constituent material of the cathode 8 (cathode material) is not particularly limited, and examples thereof include: lithium, sodium, magnesium, aluminum, silver, sodium-potassium alloys, magnesium/aluminum mixtures, magnesium/silver mixtures, magnesium/indium mixtures, aluminum/aluminum oxide (Al) 2 O 3 ) Mixtures, rare earth metals, and the like. These may be used alone in 1 kind, or in combination of 2 or more kinds.
The thickness of the cathode 8 is not particularly limited, but is preferably in the range of 0.1 to 1,000nm, and more preferably in the range of 1 to 200 nm.
The cathode 3 can be formed by a dry film formation method such as a vapor deposition method or a sputtering method.
[ hole injection layer 3]
The hole injection layer 3 has a function of receiving holes supplied from the anode 2 and injecting them into the hole transport layer 4. The hole injection layer 3 may be provided as needed or omitted.
The constituent material (hole injection material) of the hole injection layer 3 is not particularly limited, and examples thereof include: phthalocyanine compounds such as copper phthalocyanine; triphenylamine derivatives such as 4,4',4 ″ -tris [ phenyl (m-tolyl) amino ] triphenylamine; cyano compounds such as 1,4,5,8,9,12-hexaazatriphenylene hexacyanonitrile, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane; metal oxides such as vanadium oxide and molybdenum oxide; amorphous carbon; polyaniline (aniline green), poly (3, 4-ethylenedioxythiophene) -poly (styrenesulfonic acid) (PEDOT-PSS), polypyrrole, and the like. Among them, the hole injection material is preferably a polymer, and more preferably PEDOT-PSS. The hole injection material may be used alone in 1 kind, or 2 or more kinds may be used in combination.
The thickness of the hole injection layer 3 is not particularly limited, but is preferably in the range of 0.1 to 500mm, more preferably in the range of 1 to 300nm, and still more preferably in the range of 2 to 200 nm. The hole injection layer 3 may be a single layer or a laminate of 2 or more layers.
The hole injection layer 4 can be formed by a wet film formation method or a dry film formation method. In forming the hole injection layer 3 by a wet film formation method, an ink containing the above-described hole injection material is usually applied by various coating methods, and the obtained coating film is dried. The coating method is not particularly limited, and examples thereof include: ink jet printing (droplet discharge method), spin coating, casting, LB, relief, gravure, screen, nozzle, and the like. On the other hand, when the hole injection layer 3 is formed by a dry film formation method, a vacuum deposition method, a sputtering method, or the like can be preferably used.
[ hole transport layer 4]
The hole transport layer 4 has a function of receiving holes from the hole injection layer 3 and efficiently transporting the holes to the light emitting layer 6. In addition, the hole transport layer 4 may also have a function of preventing electron transport. The hole transport layer 4 may be provided as needed or omitted.
The constituent material (hole transport material) of the hole transport layer 4 is not particularly limited, and examples thereof include: low-molecular triphenylamine derivatives such as TPD (N, N '-diphenyl-N, N' -bis (3-methylphenyl) -1,1 '-biphenyl-4, 4' diamine), α -NPD (4, 4 '-bis [ N- (1-naphthyl) -N-phenylamino ] biphenyl), m-MTDATA (4, 4',4 ″ -tris (3-methylphenylphenylamino) triphenylamine); polyvinylcarbazole; conjugated compound polymers such as Poly [ N, N ' -bis (4-butylphenyl) -N, N ' -bis (phenyl) benzidine ] (Poly-TPA), polyfluorene (PF), poly [ N, N ' -bis (4-butylphenyl) -N, N ' -bis (phenyl) benzidine ] (Poly-TPD), poly [ (9, 9-dioctylfluorene-2, 7-diyl) -co- (4, 4' - (N- (sec-butylphenyl) diphenylamine)) (TFB), and polyphenylene ethylene (PPV); and copolymers containing monomer units thereof.
Among them, the hole transporting material is preferably a polymer compound obtained by polymerizing a triphenylamine derivative or a triphenylamine derivative to which a substituent is introduced, and more preferably a polymer compound obtained by polymerizing a triphenylamine derivative to which a substituent is introduced. The number of the hole transport materials may be 1 or 2 or more.
The thickness of the hole transport layer 4 is not particularly limited, but is preferably in the range of 1 to 500nm, more preferably in the range of 5 to 300nm, and still more preferably in the range of 10 to 200 nm. The hole transport layer 4 may be a single layer or a stack of 2 or more layers.
Such a hole transport layer 4 can be formed by a wet film formation method or a dry film formation method. In forming the hole transport layer 4 by a wet film formation method, an ink containing the above-mentioned hole transport material is usually applied by various coating methods, and the obtained coating film is dried. The coating method is not particularly limited, and examples thereof include: ink jet printing (droplet discharge method), spin coating, casting, LB, relief, gravure, screen, nozzle, and the like. On the other hand, when the hole transport layer 4 is formed by a dry film formation method, a vacuum deposition method, a sputtering method, or the like can be preferably used.
[ Electron injection layer 7]
The electron injection layer 7 has a function of receiving electrons supplied from the cathode 8 and injecting the electrons into the electron transport layer 6. The electron injection layer 7 may be provided as needed or omitted.
The material (electron-injecting material) constituting the electron-injecting layer 7 is not particularly limited, and examples thereof include: li 2 O、LiO、Na 2 S、Na 2 Alkali metal chalcogenides such as Se and NaO; alkaline earth metal chalcogenides such as CaO, baO, srO, beO, baS, mgO, and CaSe; alkali metal halides such as CsF, liF, naF, KF, liCl, KCl, and NaCl; alkali metal salts such as lithium 8-quinolinolato (Liq); caF 2 、BaF 2 、SrF 2 、MgF 2 、BeF 2 Such alkaline earth metal halides, and the like. Among them, alkali metal chalcogenides, alkaline earth metal halides, and alkali metal salts are preferable. The electron injection material may be used alone in 1 kind, or may be used in combination in 2 or more kinds.
The thickness of the electron injection layer 7 is not particularly limited, but is preferably in the range of 0.1 to 100nm, more preferably in the range of 0.2 to 50nm, and still more preferably in the range of 0.5 to 10 nm. The electron injection layer 7 may be a single layer or a laminate of 2 or more layers.
The electron injection layer 7 can be formed by a wet film formation method or a dry film formation method. In forming the electron injection layer 7 by a wet film formation method, an ink containing the electron injection material is usually applied by various coating methods, and the obtained coating film is dried. The coating method is not particularly limited, and examples thereof include: ink jet printing (droplet discharge method), spin coating, casting, LB, relief, gravure, screen, nozzle, and the like. On the other hand, when the electron injection layer 7 is formed by a dry film formation method, a vacuum deposition method, a sputtering method, or the like can be applied.
[ Electron transport layer 8]
The electron transport layer 8 has a function of receiving electrons from the electron injection layer 7 and efficiently transporting the electrons to the light emitting layer 5. In addition, the electron transport layer 8 may also have a function of preventing hole transport. The electron transport layer 8 may be provided as needed or omitted.
The material (electron-transporting material) constituting the electron-transporting layer 8 is not particularly limited, and examples thereof include: tris (8-hydroxyquinoline) aluminum (Alq 3), tris (4-methyl-8-hydroxyquinoline) aluminum (Almq 3), bis (10-hydroxybenzo [ h ]]Metal complexes having a quinoline skeleton or a benzoquinoline skeleton, such as quinolinium) beryllium (BeBq 2), bis (2-methyl-8-quinolinolato) (p-phenylphenolato) aluminum (BAlq), and bis (8-quinolinolato) zinc (Znq); bis [2- (2' -hydroxyphenyl) benzoxazoles]Zinc (Zn (BOX) 2 ) A metal complex having a benzoxazole skeleton as such; bis [2- (2' -hydroxyphenyl) benzothiazole]Zinc (Zn (BTZ) 2 ) A metal complex having a benzothiazole skeleton as such; 2- (4-Biphenyl) -5- (4-tert-butylphenyl) -1,3, 4-oxadiazole (PBD), 3- (4-biphenylyl) -4-phenyl-5- (4-tert-butylphenyl) -1,2, 4-Triazole (TAZ), 1, 3-bis [5- (p-tert-butylphenyl) -1,3, 4-oxadiazol-2-yl]Benzene (OXD-7), 9- [4- (5-phenyl-1, 3, 4-oxadiazol-2-yl) phenyl ]Tri-or oxadiazole derivatives such as carbazole (CO 11); 2,2' - (1, 3, 5-benzenetriyl) tris (1-phenyl-1H-benzimidazole) (TPBI), 2- [3- (dibenzothiophen-4-yl) phenyl]Imidazole derivatives such as 1-phenyl-1H-benzimidazole (mDBTBIm-II); a quinoline derivative; a perylene derivative; pyridine derivatives such as 4, 7-diphenyl-1, 10-phenanthroline (BPhen); a pyrimidine derivative; a triazine derivative; a quinoxaline derivative; a diphenylquinone derivative; nitro-substituted fluorene derivatives; zinc oxide (ZnO) and titanium oxide (TiO) 2 ) Such metal oxides, and the like. Among them, preferred electron-transporting materials are imidazole derivatives, pyridine derivatives, pyrimidine derivatives, triazine derivatives, and metal oxides (inorganic oxides). The electron-transporting material may be used alone in 1 kind, or 2 or more kinds may be used in combination.
The thickness of the electron transport layer 7 is not particularly limited, but is preferably in the range of 5 to 500nm, and more preferably in the range of 5 to 200 nm. The electron transport layer 6 may be a single layer, or 2 or more layers may be stacked.
Such an electron transport layer 7 can be formed by a wet film formation method or a dry film formation method. In forming the electron transporting layer 6 by a wet film formation method, an ink containing the electron transporting material is usually applied by various coating methods, and the obtained coating film is dried. The coating method is not particularly limited, and examples thereof include: ink jet printing (droplet discharge method), spin coating, casting, LB, relief, gravure, screen, nozzle, and the like. On the other hand, when the electron transport layer 6 is formed by a dry film forming method, a vacuum deposition method, a sputtering method, or the like can be applied.
[ light-emitting layer 5]
The light-emitting layer 5 has a function of emitting light by energy generated by recombination of holes and electrons injected into the light-emitting layer 5. The light-emitting layer 5 of the present embodiment emits blue light having a wavelength in the range of 400 to 500nm, more preferably in the range of 420 to 480 nm.
The light-emitting layer 5 preferably includes a light-emitting material (guest material or dopant material) and a host material. In this case, the mass ratio of the host material to the light-emitting material is not particularly limited, and is preferably 10:1 to 300:1, in the above range. As the light-emitting material, a compound capable of converting singlet excitation energy into light or a compound capable of converting triplet excitation energy into light can be used. In addition, the light-emitting material preferably contains at least 1 selected from the group consisting of an organic low-molecular fluorescent material, an organic high-molecular fluorescent material, and an organic phosphorescent material.
Examples of the compound capable of converting the singlet excitation energy into light include: an organic low-molecular fluorescent material or an organic high-molecular fluorescent material which emits fluorescence.
The organic low-molecular fluorescent material is preferably one having an anthracene structure, a tetracene structure,
Figure BDA0004092365490000851
A compound having a structure, a phenanthrene structure, a pyrene structure, a perylene structure, a stilbene structure, an acridone structure, a coumarin structure, a phenoxazine structure or a phenothiazine structure.
Specific examples of the organic low-molecular fluorescent material include: 5, 6-bis [4- (10-phenyl-9-anthracenyl) phenyl]-2,2 '-bipyridine, 5, 6-bis [4' - (10-phenyl-9-anthracenyl) biphenyl-4-yl]-2,2 '-bipyridine, N' -bis [4- (9H-carbazol-9-yl) phenyl]-N, N ' -diphenylstilbene-4, 4' -diamine, 4- (9H-carbazol-9-yl) -4' - (10)-phenyl-9-anthracenyl) triphenylamine, 4- (9H-carbazol-9-yl) -4' - (9, 10-diphenyl-2-anthracenyl) triphenylamine, N, 9-diphenyl-N- [4- (10-phenyl-9-anthracenyl) phenyl]-9H-carbazol-3-amine, 4- (10-phenyl-9-anthracenyl) -4' - (9-phenyl-9H-carbazol-3-yl) triphenylamine, 4- [4- (10-phenyl-9-anthracenyl) phenyl]-4' - (9-phenyl-9H-carbazol-3-yl) triphenylamine, perylene, 2,5,8, 11-tetra (tert-butyl) perylene, N ' -diphenyl-N, N ' -bis [4- (9-phenyl-9H-fluoren-9-yl) phenyl]Pyrene-1, 6-diamine, N '-bis (3-methylphenyl) -N, N' -bis [3- (9-phenyl-9H-fluoren-9-yl) phenyl]-pyrene-1, 6-diamine, N ' -bis (dibenzofuran-2-yl) -N, N ' -diphenylpyrene-1, 6-diamine, N ' -bis (dibenzothiophen-2-yl) -N, N ' -diphenylpyrene-1, 6-diamine, N ' - (2-tert-butylanthracene-9, 10-diylbis-4, 1-phenylene) bis [ N, N ', N ' -triphenyl-1, 4-phenylenediamine]N, 9-diphenyl-N- [4- (9, 10-diphenyl-2-anthryl) phenyl ]-9H-carbazol-3-amine, N- [4- (9, 10-diphenyl-2-anthracenyl) phenyl]N, N ', N ' -triphenyl-1, 4-phenylenediamine, N, N, N ', N ', N ", N", N ' "-octaphenyldibenzo [ g, p]
Figure BDA0004092365490000852
-2,7,10, 15-tetramine, coumarin 30, N- (9, 10-diphenyl-2-anthracenyl) -N, 9-diphenyl-9H-carbazol-3-amine, N- (9, 10-diphenyl-2-anthracenyl) -N, N ', N' -triphenyl-1, 4-phenylenediamine, N, 9-triphenylanthracene-9-amine, coumarin 6, coumarin 545T, N '-diphenylquinacridone, rubrene, 5, 12-bis (1, 1' -biphenyl-4-yl) -6, 11-diphenyltetracene, 2- (2- {2- [4- (dimethylamino) phenyl ] naphthalene]Vinyl } -6-methyl-4H-pyran-4-ylidene) malononitrile, 2- { 2-methyl-6- [2- (2, 3,6, 7-tetrahydro-1H, 5H-benzo [ ij ]]Quinolizin-9-yl) ethenyl]-4H-pyran-4-ylidene malononitrile, N, N, N ', N' -tetrakis (4-methylphenyl) tetracene-5, 11-diamine, 7, 14-diphenyl-N, N, N ', N' -tetrakis (4-methylphenyl) acenaphtho [1,2-a ] acenaphthylene]Fluoranthene-3, 10-diamine, 2- { 2-isopropyl-6- [2- (1, 7-tetramethyl-2, 3,6, 7-tetrahydro-1H, 5H-benzo [ ij ]]Quinolizin-9-yl) ethenyl]-4H-pyran-4-ylidene malononitrile, 2- { 2-tert-butyl-6- [2- (1, 7-tetramethyl-2, 3,6, 7-tetrahydro-1H, 5H-benzo [ ij ]]Quinolizin-9-yl) ethenyl]-4H-pyran-4-ylidene malononitrile, 2- (2, 6-bis {2- [4- (dimethylamino) phenyl group ]Vinyl } -4H-pyran-4-ylidene) malononitrile, 2- {2, 6-bis [2- (8-methoxy-1, 7-tetramethyl-)-2,3,6, 7-tetrahydro-1H, 5H-benzo [ ij ]]Quinolizin-9-yl) ethenyl]-4H-pyran-4-ylidene malononitrile, 5,10,15,20-tetraphenylbis-benzo [5,6 ]]Indeno [1,2,3-cd:1',2',3' -lm]Perylene, and the like.
Specific examples of the organic polymer fluorescent material include: a homopolymer composed of units based on a fluorene derivative; a copolymer composed of a fluorene derivative-based unit and a tetraphenyl phenylenediamine derivative-based unit; homopolymers composed of units based on terphenyl derivatives; homopolymers composed of units based on diphenylbenzofluorene derivatives, and the like.
The compound capable of converting triplet excitation energy into light is preferably an organic phosphorescent material which emits phosphorescence. Specific examples of the organic phosphorescent material include: a metal complex comprising at least 1 metal atom selected from the group consisting of iridium, rhodium, platinum, ruthenium, osmium, scandium, yttrium, gadolinium, palladium, silver, gold, and aluminum. Among them, the organic phosphorescent material is preferably a metal complex containing at least 1 metal atom selected from the group consisting of iridium, rhodium, platinum, ruthenium, osmium, scandium, yttrium, gadolinium and palladium, more preferably a metal complex containing at least 1 metal atom selected from the group consisting of iridium, rhodium, platinum and ruthenium, and further preferably an iridium complex or a platinum complex.
As the host material, at least 1 kind of compound having an energy gap larger than that of the light-emitting material is preferably used. Further, when the light-emitting material is a phosphorescent material, it is preferable to select a compound having triplet excitation energy larger than triplet excitation energy (energy difference between a ground state and a triplet excited state) of the light-emitting material as a host material.
Examples of host materials include: tris (8-hydroxyquinoline) aluminium (III), tris (4-methyl-8-hydroxyquinoline) aluminium (III), bis (10-hydroxybenzo [ h)]Quinolyl) beryllium (II), bis (2-methyl-8-hydroxyquinoline) (4-phenylphenol) aluminum (III), bis (8-hydroxyquinoline) zinc (II), bis [2- (2-benzoxazolyl) phenol]Zinc (II), bis [2- (2-benzothiazolyl) phenol]Zinc (II), 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3, 4-oxadiazole, 1, 3-bis [5- (p-tert-butylphenyl) -1,3, 4-oxadiazol-2-yl]Benzene, 3- (4-biphenylyl) -4-phenyl-5- (4-tert-butyl)Phenyl) -1,2, 4-triazole, 2' - (1, 3, 5-benzenetriyl) tris (1-phenyl-1H-benzimidazole), bathophenanthroline (bathophenanthrine), bathocuproine (bathocuproine), 9- [4- (5-phenyl-1, 3, 4-oxadiazol-2-yl) phenyl]-9H-carbazole, 9, 10-diphenylanthracene, N-diphenyl-9- [4- (10-phenyl-9-anthracenyl) phenyl ]-9H-carbazol-3-amine, 4- (10-phenyl-9-anthracenyl) triphenylamine, N, 9-diphenyl-N- {4- [4- (10-phenyl-9-anthracenyl) phenyl]Phenyl } -9H-carbazol-3-amine, 6, 12-dimethoxy-5, 11-diphenyl
Figure BDA0004092365490000861
9- [4- (10-phenyl-9-anthryl) phenyl]-9H-carbazole, 3, 6-diphenyl-9- [4- (10-phenyl-9-anthracenyl) phenyl]-9H-carbazole, 9-phenyl-3- [4- (10-phenyl-9-anthracenyl) phenyl]-9H-carbazole, 7- [4- (10-phenyl-9-anthracenyl) phenyl]-7H-dibenzo [ c, g]Carbazole, 6- [3- (9, 10-diphenyl-2-anthracenyl) phenyl]-benzo [ b ]]Naphtho [1,2-d ]]Furan, 9-phenyl-10- {4- (9-phenyl-9H-fluoren-9-yl) biphenyl-4 '-yl } anthracene, 9, 10-bis (3, 5-diphenylphenyl) anthracene, 9, 10-bis (2-naphthyl) anthracene, 2-tert-butyl-9, 10-bis (2-naphthyl) anthracene, 9' -bianthracene, 9'- (stilbene-3, 3' -diyl) phenanthrene, 9'- (stilbene-4, 4' -diyl) phenanthrene, 1,3, 5-tris (1-pyrenyl) benzene, 5, 12-diphenyltetracene, 5, 12-bis (biphenyl-2-yl) tetracene, or the like. These host materials may be used alone in 1 kind, or 2 or more kinds may be used in combination.
The thickness of the light-emitting layer 5 is not particularly limited, but is preferably in the range of 1 to 100nm, and more preferably in the range of 1 to 50 nm.
Such a light-emitting layer 5 can be formed by a wet film formation method or a dry film formation method. When the light-emitting layer 5 is formed by a wet film-forming method, an ink containing the light-emitting material and the host material is usually applied by various application methods, and the obtained coating film is dried. The coating method is not particularly limited, and examples thereof include an ink jet printing method (droplet discharging method), a spin coating method, a casting method, an LB method, a relief printing method, a gravure printing method, a screen printing method, and a nozzle printing method. On the other hand, when the light-emitting layer 5 is formed by a dry film formation method, a vacuum deposition method, a sputtering method, or the like can be applied.
The EL light source unit 200 may further include, for example, banks (partition walls) that partition the hole injection layer 3, the hole transport layer 4, and the light-emitting layer 5. The height of the bank is not particularly limited, but is preferably in the range of 0.1 to 5 μm, more preferably in the range of 0.2 to 4 μm, and still more preferably in the range of 0.2 to 3 μm.
The opening width of the bank is preferably in the range of 10 to 200. Mu.m, more preferably in the range of 30 to 200. Mu.m, and still more preferably in the range of 50 to 100. Mu.m. The opening length of the bank is preferably in the range of 10 to 400. Mu.m, more preferably in the range of 20 to 200. Mu.m, and still more preferably in the range of 50 to 200. Mu.m. The bank inclination angle is preferably in the range of 10 to 100 °, more preferably in the range of 10 to 90 °, and still more preferably in the range of 10 to 80 °.
< light conversion layer 12 >
The light conversion layer 12 converts light emitted from the EL light source section 200 and re-emits light, or transmits light emitted from the EL light source section 200. As shown in fig. 3, the pixel unit 20 includes: a 1 st pixel unit 20a that converts light having a wavelength in the above range to emit red light; a 2 nd pixel unit 20b that converts light having a wavelength in the above range to emit green light; and a 3 rd pixel unit 20c that transmits light having a wavelength in the above range. The 1 st pixel unit 20a, the 2 nd pixel unit 20b, and the 3 rd pixel unit 20c may be sequentially and repeatedly arranged in a lattice shape. Light shielding portions 30 for shielding light are provided between adjacent pixel units, that is, between the 1 st pixel unit 20a and the 2 nd pixel unit 20b, between the 2 nd pixel unit 20b and the 3 rd pixel unit 20c, and between the 3 rd pixel unit 20c and the 1 st pixel unit 20 a. In other words, these adjacent pixel portions are separated from each other by the light shielding portion 30. The 1 st pixel portion 20a and the 2 nd pixel portion 20b may contain color materials corresponding to the respective colors.
The 1 st pixel portion 20a and the 2 nd pixel portion 20b each contain a cured product of the light-emitting particle-containing ink composition of the above embodiment. The cured product preferably contains the light-emitting particles 90 and a curing component as essential components, and further contains light-diffusing particles to scatter light and reliably extract the light to the outside. The curing component is a cured product of a thermosetting resin, for example, a cured product obtained by polymerization of an epoxy group-containing resin. That is, the 1 st pixel portion 20a includes: a 1 st curing component 22a, and 1 st light-emitting particles 90a and 1 st light-diffusing particles 21a dispersed in the 1 st curing component 22a, respectively. Similarly, the 2 nd pixel portion 20b includes: a 2 nd curing component 22b, and 1 st light-emitting particles 90b and 1 st light-diffusing particles 21b dispersed in the 2 nd curing component 22b, respectively. In the 1 st pixel portion 20a and the 2 nd pixel portion 20b, the 1 st curing component 22a and the 2 nd curing component 22b may be the same or different, and the 1 st light diffusion particle 22a and the 2 nd light diffusion particle 22b may be the same or different.
The 1 st light-emitting particle 90a is a red light-emitting particle that absorbs light having a wavelength in the range of 420 to 480nm and emits light having a light emission peak wavelength in the range of 605 to 665 nm. That is, the 1 st pixel part 20a may be referred to as a red pixel part for converting blue light into red light instead. The 2 nd light-emitting particle 90b is a green light-emitting particle that absorbs light having a wavelength in the range of 420 to 480nm and emits light having a light-emission peak wavelength in the range of 500 to 560 nm. That is, the 2 nd pixel part 20b may be referred to as a green pixel part for converting blue light into green light instead.
The content of the light-emitting particles 90 in the pixel portions 20a and 20b including the cured product of the light-emitting particle-containing ink composition is preferably 0.1 mass% or more based on the total mass of the cured product of the light-emitting particle-containing ink composition, from the viewpoint of further improving the external quantum efficiency and the viewpoint of obtaining excellent light emission intensity. From the same viewpoint, the content of the light-emitting particles 90 is preferably 1 mass% or more, 2 mass% or more, 3 mass% or more, and 5 mass% or more based on the total mass of the cured product of the light-emitting particle-containing ink composition. The content of the light-emitting particles 90 is preferably 30 mass% or less based on the total mass of the ink composition containing the light-emitting particles, from the viewpoint of excellent reliability of the pixel portions 20a and 20b and the viewpoint of obtaining excellent light emission intensity. From the same viewpoint, the content of the luminescent particles 90 is preferably 25% by mass or less, 20% by mass or less, 15% by mass or less, and 10% by mass or less, based on the total mass of the cured product of the ink composition containing the luminescent particles.
The content of the light diffusing particles 21a and 21b in the pixel portions 20a and 20b containing the cured product of the ink composition containing the light emitting particles is preferably 0.1 mass% or more, 1 mass% or more, 5 mass% or more, 7 mass% or more, 10 mass% or more, and 12 mass% or more based on the total mass of the cured product of the ink composition, from the viewpoint of further improving the effect of improving the external quantum efficiency. The content of the light diffusing particles 21a and 21b is preferably 60% by mass or less, 50% by mass or less, 40% by mass or less, 30% by mass or less, 25% by mass or less, 20% by mass or less, and 15% by mass or less, based on the total mass of the cured product of the ink composition, from the viewpoint of further improving the effect of improving the external quantum efficiency and from the viewpoint of excellent reliability of the pixel portion 20.
The 3 rd pixel portion 20c has a transmittance of 30% or more with respect to light having a wavelength in the range of 420 to 480 nm. Therefore, when a light source that emits light having a wavelength in the range of 420 to 480nm is used, the 3 rd pixel unit 20c functions as a blue pixel unit. The 3 rd pixel portion 20c includes, for example, a cured product of a composition containing the above thermosetting resin. The cured product contained 22cc of the 3 rd curing component. The 3 rd curing component 22c is a cured product of a thermosetting resin, specifically, a cured product obtained by polymerization of an epoxy group-containing resin. That is, the 3 rd pixel portion 20c contains the 3 rd curing component 22c. When the 3 rd pixel portion 20c contains the cured product, the composition containing a thermosetting resin may further contain components other than the thermosetting resin, the curing agent, and the solvent, among the components contained in the light-emitting particle-containing ink composition, as long as the transmittance of light having a wavelength in the range of 420 to 480nm is 30% or more. The transmittance of the 3 rd pixel portion 20c can be measured by a micro spectrometer.
The thickness of the pixel portion (the 1 st pixel portion 20a, the 2 nd pixel portion 20b, and the 3 rd pixel portion 20 c) is not particularly limited, and is preferably 1 μm or more, 2 μm or more, and 3 μm or more, for example. The thickness of the pixel portion (the 1 st pixel portion 20a, the 2 nd pixel portion 20b, and the 3 rd pixel portion 20 c) is preferably 30 μm or less, 25 μm or less, and 20 μm or less, for example.
[ method for Forming light-converting layer 12 ]
The light conversion layer 12 including the 1 st to 3 rd pixel portions 20a to 20c can be formed by drying and heating a coating film formed by a wet film formation method to cure the coating film. The 1 st pixel portion 20a and the 2 nd pixel portion 20b can be formed using the ink composition containing the light-emitting particles of the present invention, and the 3 rd pixel portion 20c can be formed using an ink composition not containing the light-emitting particles 90 contained in the ink composition containing the light-emitting particles. The method of forming a coating film using the ink composition containing luminescent particles of the present invention will be described in detail below, but the same procedure can be performed when the ink composition containing luminescent particles of the present invention is used.
The method for coating the coating film of the ink composition containing luminescent particles of the present invention is not particularly limited, and examples thereof include: inkjet printing (piezoelectric or thermal droplet discharge), spin coating, casting, LB, relief printing, gravure printing, screen printing, nozzle printing, and the like. Here, the nozzle printing method is a method of applying an ink composition containing light-emitting particles in a liquid column form from a nozzle hole in a stripe form. Among them, the application method is preferably an ink jet printing method (particularly, a droplet discharge method of a piezoelectric method). This can reduce the heat load when the ink composition containing the light-emitting particles is discharged, and can prevent the light-emitting particles 90 from being deteriorated by heat.
The conditions of the inkjet printing method are preferably set as follows. The discharge amount of the ink composition containing the light-emitting particles is not particularly limited, but is preferably 1 to 50 pL/time, more preferably 1 to 30 pL/time, and still more preferably 1 to 20 pL/time.
The aperture diameter of the nozzle hole is preferably in the range of 5 to 50 μm, and more preferably in the range of 10 to 30 μm. This prevents clogging of the nozzle hole and improves the ejection accuracy of the ink composition containing the light-emitting particles.
The temperature at the time of forming the coating film is not particularly limited, but is preferably in the range of 10 to 50 ℃, more preferably in the range of 15 to 40 ℃, and still more preferably in the range of 15 to 30 ℃. When the droplets are discharged at the above temperature, crystallization of various components contained in the ink composition containing the light-emitting particles can be suppressed.
The relative humidity at the time of forming a coating film is also not particularly limited, but is preferably in the range of 0.01ppm to 80%, more preferably in the range of 0.05ppm to 60%, still more preferably in the range of 0.1ppm to 15%, particularly preferably in the range of 1ppm to 1%, and most preferably in the range of 5 to 100 ppm. When the relative humidity is not less than the lower limit, the conditions for forming the coating film can be easily controlled. On the other hand, if the relative humidity is not more than the upper limit, the amount of moisture adsorbed on the coating film, which may adversely affect the obtained light-converting layer 12, can be reduced.
When the organic solvent is contained in the ink composition containing the light-emitting particles, the organic solvent is preferably removed from the coating film by drying before curing the coating film. The drying may be performed by leaving at room temperature (25 ℃) or by heating, but from the viewpoint of productivity, it is preferable to perform the drying by heating. When drying is performed by heating, the drying temperature is not particularly limited, and is preferably a temperature in consideration of the boiling point and vapor pressure of the organic solvent used in the ink composition containing the light-emitting particles. The drying temperature is preferably 50 to 130 ℃, more preferably 60 to 120 ℃, and particularly preferably 70 to 110 ℃ as the preliminary baking step for removing the organic solvent in the coating film. If the drying temperature is not higher than 50 ℃, the organic solvent may not be removed, while if the temperature is not lower than 130 ℃, the organic solvent may be instantaneously removed, which may result in a significant deterioration in the appearance of the coating film, which is not preferable. The drying is preferably performed under reduced pressure, more preferably under reduced pressure of 0.001 to 100 Pa. Further, the drying time is preferably 1 to 30 minutes, more preferably 1 to 15 minutes, and particularly preferably 1 to 10 minutes. By drying the coating film under such drying conditions, the organic solvent can be surely removed from the coating film, and the external quantum efficiency of the obtained light-converting layer 12 can be further improved.
The ink composition containing the luminescent particles of the present invention can be cured by irradiation with active energy rays (e.g., ultraviolet rays). As the irradiation source (light source), for example, a mercury lamp, a metal halide lamp, a xenon lamp, an LED, or the like is used, and an LED is preferable from the viewpoint of reducing the heat load to the coating film and reducing power consumption.
The wavelength of the light to be irradiated is preferably 200nm or more, and more preferably 440nm or less. Further, the intensity of light is preferably 0.2 to 2kW/cm 2 More preferably 0.4 to 1kW/cm 2 . If the intensity of light is less than 0.2kW/cm 2 The coating film cannot be sufficiently cured, and the intensity of light is 2kW/cm 2 As described above, the degree of curing becomes uneven between the surface and the inside of the coating film, and the smoothness of the coating film surface is not preferable. The dose of light irradiation (exposure dose) is preferably 10mJ/cm 2 More preferably 4000mJ/cm 2 The following.
The curing of the coating film can be carried out in air or in an inert gas, but is preferably carried out in an inert gas in order to suppress oxygen inhibition of the coating film surface and oxidation of the coating film. Examples of the inert gas include: nitrogen, argon, carbon dioxide, and the like. By curing the coating film under such conditions, the coating film can be completely cured, and therefore the external quantum efficiency of the obtained light-converting layer 9 can be further improved.
As described above, since the luminescent particle ink composition of the present invention is excellent in stability to heat, the pixel portion 20 which is a molded body after heat curing can also realize good luminescence. Further, since the light-emitting particle composition of the present invention has excellent dispersibility, the light-emitting particles 90 have excellent dispersibility, and a flat pixel portion 20 can be obtained.
Further, the light-emitting particles 90 included in the 1 st pixel portion 20a and the 2 nd pixel portion 20b include semiconductor nanocrystals having a perovskite type, and therefore, have a large absorption in a wavelength region of 300 to 500 nm. Therefore, in the 1 st pixel unit 20a and the 2 nd pixel unit 20b, the blue light incident on the 1 st pixel unit 20a and the 2 nd pixel unit 20b can be prevented from being transmitted to the upper substrate 13 side, that is, the blue light can be prevented from leaking to the upper substrate 13 side. Therefore, according to the 1 st pixel unit 20a and the 2 nd pixel unit 20b of the present invention, red light and green light having high color purity can be extracted without mixing blue light.
The light shielding portion 30 is a so-called black matrix provided for the purpose of separating adjacent pixel portions 20 to prevent color mixing and light leakage from the light source. The material constituting the light-shielding portion 30 is not particularly limited, and a cured product of an ink composition containing light-shielding particles such as carbon fine particles, metal oxide, inorganic pigment, and organic pigment in a binder polymer may be used in addition to a metal such as chromium. The binder polymer used here may be 1 or 2 or more types of resins such as polyimide resin, acrylic resin, epoxy resin, polyacrylamide, polyvinyl alcohol, gelatin, casein, cellulose, or the like, a photosensitive resin, an O/W emulsion type ink composition (for example, a material obtained by emulsifying a reactive silicone), or the like. The thickness of the light shielding portion 30 is preferably 1 μm to 15 μm, for example.
The light-emitting element 100 may be configured as a bottom emission type instead of a top emission type. In addition, instead of the EL light source section 200, another light source may be used for the light emitting element 100.
The ink composition containing luminescent particles of the present invention, the method for producing the same, and the light-emitting element including the light conversion layer produced using the ink composition have been described above, but the present invention is not limited to the configuration of the above embodiment. For example, the light-emitting particles, the light-emitting particle dispersion, the ink composition containing light-emitting particles, and the light-emitting element of the present invention may each have any other configuration as well as the configuration of the above embodiment, and may be replaced with any configuration that exhibits the same function. The method for producing light-emitting particles of the present invention may have other steps of any purpose in the configuration of the above embodiment, and may be replaced with any steps that exhibit the same effects.
Examples
The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. Unless otherwise specified, "part" and "%" are based on mass.
In the following examples, the operation of producing the light-emitting particles and the operation of producing the ink composition containing the light-emitting particles were carried out in a glove box filled with nitrogen gas or a flask in which the flow of nitrogen gas in the atmosphere was blocked. All the raw materials exemplified below were used after the atmosphere in the vessel was replaced with nitrogen gas introduced into the vessel. The liquid material is used after oxygen dissolved in the liquid material is replaced with nitrogen gas introduced into the container.
The isobornyl acrylate, isobornyl methacrylate, lauryl acrylate, lauryl methacrylate, phenoxyethyl methacrylate, 1, 6-hexanediol diacrylate, 1, 6-hexanediol dimethacrylate, 2 mol of propoxy-modified neopentyl glycol diacrylate, 3 mol of propoxy-modified glyceryl triacrylate, and ditrimethylolpropane tetraacrylate used hereinafter were dehydrated for 48 hours or more using a molecular sieve (using 3A or 4A). For titanium oxide, it was heated at 120 ℃ under reduced pressure of 1mmHg for 2 hours before use, and left to cool under a nitrogen atmosphere.
< preparation of luminescent particle Dispersion >
(preparation of luminescent particle Dispersion 1)
As the hollow particles, particles of "SiliNax SP-PN (b)" manufactured by Nissan industries, ltd. The hollow particles are silica particles having a hollow structure and an overall rectangular parallelepiped shape, and have an average outer diameter of 100nm and an average inner diameter of 80nm. First, the hollow silica particles were dried at 150 ℃ for 8 hours under reduced pressure. Next, 200.0 parts by mass of the dried hollow silica particles were weighed into a tussian funnel.
Next, 63.9 parts by mass of cesium bromide, 110.1 parts by mass of lead (II) bromide, and 3000 parts by mass of N-methylformamide were supplied to the three-necked flask under an argon atmosphere, and stirred at 50 ℃ for 30 minutes, thereby obtaining a lead cesium tribromide solution.
Then, the dried hollow silica particles are supplied to the three-necked flask, the obtained lead cesium tribromide solution is impregnated into the hollow silica particles, and then the excess lead cesium tribromide solution is removed by filtration, and the solid matter is recovered. The obtained solid was dried under reduced pressure at 150 ℃ for 1 hour to obtain luminescent particles X-1 (212.7 parts by mass) in which perovskite-type nanocrystals composed of cesium lead tribromide were encapsulated in hollow silica particles. The luminescent particle X-1 is a hollow particle-encapsulated luminescent particle.
The obtained light-emitting particles X-1 were dispersed in isobornyl methacrylate (Lightester IB-X; manufactured by Kyoeisha chemical Co., ltd.) so that the solid content concentration became 2.5 mass%, thereby obtaining a light-emitting particle dispersion 1 in which the light-emitting particles X-1 were dispersed.
(preparation of light-emitting particle Dispersion 2)
190 parts by mass of heptane were supplied to a four-necked flask equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen inlet tube, and the temperature was raised to 85 ℃. After reaching this temperature, a mixture of 66.5 parts by mass of lauryl methacrylate, 3.5 parts by mass of dimethylaminoethyl methacrylate and 0.5 part by mass of dimethyl 2, 2-azobis (2-methylpropionate) dissolved in 20 parts by mass of heptane was added dropwise over a period of 3.5 hours to the heptane in the four-necked flask, and the reaction was continued by keeping the same temperature for 10 hours even after the completion of the addition. Then, the temperature of the reaction solution was reduced to 50 ℃, and then a solution prepared by dissolving 0.01 part by mass of t-butylcatechol in 1.0 part by mass of heptane was added, and further 1.0 part by mass of glycidyl methacrylate was added, and then the temperature was raised to 85 ℃, and the reaction was continued at the same temperature for 5 hours. Thereby, a solution containing the polymer (P) was obtained. The amount of the nonvolatile component (NV) contained in the solution was 25.1% by mass, and the weight-average molecular weight (Mw) of the polymer (P) was 10,000.
Then, a solution containing 26 parts by mass of heptane, 3 parts by mass of the light-emitting particles X-1, and 3.6 parts by mass of the polymer (P) was supplied to a four-necked flask equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen gas inlet tube. Further, 0.2 parts by mass of ethylene glycol dimethacrylate, 0.4 parts by mass of methyl methacrylate, and 0.12 parts by mass of dimethyl 2, 2-azobis (2-methylpropionate) were supplied to the four-necked flask. Then, the mixture in the four-necked flask was stirred at room temperature for 30 minutes, and then heated to 80 ℃ to continue the reaction at this temperature for 15 hours. After the completion of the reaction, the polymer not adsorbed to the light-emitting particle A in the reaction solution was separated by centrifugation, and then the precipitated particles were vacuum-dried at room temperature for 2 hours to obtain a polymer-coated light-emitting particle X-2 in which the surface of the light-emitting particle X-1 as a mother particle was coated with a polymer layer composed of a hydrophobic polymer.
The obtained polymer-coated light-emitting particle X-2 was observed with a transmission electron microscope, and as a result, a polymer layer having a thickness of about 10nm was formed on the surface of the light-emitting particle X-2. Then, the obtained polymer-coated light-emitting particles X-2 were dispersed in isobornyl methacrylate so that the solid content concentration became 2.5 mass%, thereby obtaining a light-emitting particle dispersion liquid 2.
(preparation of light-emitting particle Dispersion 3)
First, the same hollow silica particles (manufactured by Nissan corporation, "SiliNax SP-PN (b)") as used in the light-emitting particle dispersion 1 were dried under reduced pressure at 150 ℃ for 8 hours. Next, 200.0 parts by mass of the dried hollow silica particles were weighed into a tung mountain funnel.
Next, 63.9 parts by mass of cesium bromide, 110.1 parts by mass of lead (II) bromide, and 3000 parts by mass of N-methylformamide were supplied to a three-necked flask under an argon atmosphere, and stirred at 50 ℃ for 30 minutes, thereby obtaining a lead cesium tribromide solution.
Next, hollow silica particles were supplied to the three-necked flask, the hollow silica particles were impregnated with the obtained lead tribromide solution, and then the excess lead cesium tribromide solution was removed by filtration to recover a solid material. Then, the obtained solid was dried under reduced pressure at 120 ℃ for 1 hour to obtain light-emitting particles X-3 in which perovskite type nanocrystals composed of cesium lead tribromide were encapsulated in hollow silica particles. The luminescent particle X-3 is a hollow particle-encapsulated luminescent particle.
The obtained light-emitting particles X-3 were dispersed in isobornyl methacrylate so that the solid content concentration became 2.5 mass%, thereby obtaining a light-emitting particle dispersion liquid 3 in which the light-emitting particles X-3 were dispersed.
(preparation of light-emitting particle Dispersion 4)
First, 15.0mg of lead (II) bromide, 8.5mg of cesium bromide, oleic acid, and oleylamine were added to 1mL of an N, N-dimethylformamide solution, thereby obtaining a solution of a raw material compound containing semiconductor nanocrystals.
On the other hand, 0.25mL of 3-aminopropyltriethoxysilane was mixed with 5mL of toluene to obtain an ethoxysilane-toluene solution. Then, the above 1mL of the solution of the raw material compound containing the semiconductor nanocrystal was added to the above 20mL of the ethoxysilane-toluene solution and stirred at room temperature under the atmosphere, and further directly stirred at 1500rpm for 20 seconds at room temperature. Then, the solid material was recovered by centrifugation (12,100 rpm, 5 minutes) to obtain luminescent particles X-4.
The luminescent particles X-4 are perovskite type cesium lead tribromide crystals with a surface layer, and the average particle diameter is 11nm when observed by a transmission electron microscope. The surface layer was a layer made of 3-aminopropyltriethoxysilane and had a thickness of about 1nm. That is, the light-emitting particle X-4 is a particle coated with silica.
Further, the light-emitting particles X-4 were dispersed in isobornyl methacrylate so that the solid content concentration became 2.5 mass%, thereby obtaining a light-emitting particle dispersion 4 in which the light-emitting particles X-4 were dispersed.
(preparation of light-emitting particle Dispersion 5)
First, a polymer-coated light-emitting particle X-5 in which the light-emitting particle X-4 as a mother particle is coated with a polymer layer made of a hydrophobic polymer is obtained by the same operation as that for the polymer-coated light-emitting particle X-2 except that the light-emitting particle X-4 is used in place of the light-emitting particle X-1. Next, a light-emitting particle dispersion liquid 5 was obtained in the same manner as the light-emitting particle dispersion liquid 2 except that the polymer-coated light-emitting particles X-5 were used as the light-emitting particles instead of the polymer-coated light-emitting particles X-2.
(preparation of luminescent particle Dispersion 6)
First, 0.814 parts by mass of cesium carbonate, 40 parts by mass of octadecene, and 2.5 parts by mass of oleic acid were supplied to a four-necked flask equipped with a thermometer, a stirrer, a septum, and a nitrogen inlet tube, and heated and stirred at 150 ℃ in a nitrogen atmosphere until a uniform solution was obtained. After all dissolved, it was cooled to 100 ℃, thereby obtaining a cesium oleate solution.
Then, 0.069 parts by mass of lead (II) bromide and 5 parts by mass of octadecene were supplied to a four-necked flask equipped with a thermometer, a stirrer, a septum and a nitrogen inlet, and heated and stirred at 120 ℃ for 1 hour under a nitrogen atmosphere. Then, 0.5 parts by mass of oleylamine and 0.5 parts by mass of oleic acid were supplied to the four-necked flask, and the mixture was heated and stirred at 160 ℃ in a nitrogen atmosphere until a uniform solution was obtained. Further, 0.4 parts by weight of a cesium oleate solution was supplied to the four-necked flask, and after stirring at 160 ℃ for 5 seconds, the four-necked flask was cooled in an ice bath. The obtained reaction solution was separated by centrifugal separation, and the supernatant was removed, thereby obtaining 0.45 parts by mass of perovskite-type cesium lead tribromide crystals coordinated with oleic acid and oleylamine as the luminescent particles X-6. Then, the obtained luminescent particles X-6 were dispersed in isobornyl methacrylate so that the solid content concentration became 2.5 mass%, thereby obtaining a luminescent particle dispersion liquid 6.
(preparation of light-emitting particle Dispersion 7)
Isobornyl methacrylate and phenoxyethyl methacrylate were used in a ratio of 30 parts by mass: light-emitting particle dispersion liquid 7 was obtained in the same manner as light-emitting particle dispersion liquid 1 except that a solution obtained by mixing 28.5 parts by mass in place of isobornyl methacrylate was used as the photopolymerizable compound.
(preparation of luminescent particle Dispersion 8)
Isobornyl methacrylate and phenoxyethyl methacrylate were used in a ratio of 30 parts by mass: a light-emitting particle dispersion liquid 8 was obtained in the same manner as the light-emitting particle dispersion liquid 4 except that a solution obtained by mixing the components in a ratio of 28.5 parts by mass was used as the photopolymerizable compound instead of isobornyl methacrylate.
(preparation of luminescent particle Dispersion 9)
Isobornyl methacrylate and lauryl methacrylate were used in an amount of 30 parts by mass: light-emitting particle dispersion liquid 9 was obtained in the same manner as light-emitting particle dispersion liquid 1 except that a solution obtained by mixing 28.5 parts by mass in place of isobornyl methacrylate was used as the photopolymerizable compound.
(preparation of light-emitting particle Dispersion 10)
Isobornyl methacrylate and lauryl methacrylate were used in 31.5 parts by mass: a light-emitting particle dispersion liquid 10 was obtained in the same manner as the light-emitting particle dispersion liquid 1 except that a solution obtained by mixing 19.5 parts by mass in place of isobornyl methacrylate was used as a photopolymerizable compound and the concentration of the light-emitting particles X-1 was adjusted to 2.86 mass%.
(preparation of light-emitting particle Dispersion 11)
Isobornyl methacrylate and lauryl methacrylate were used in 16 parts by mass: a light-emitting particle dispersion liquid 11 was obtained in the same manner as the light-emitting particle dispersion liquid 1 except that a solution obtained by mixing 30 parts by mass in place of isobornyl methacrylate was used as the photopolymerizable compound and the concentration of the light-emitting particles X-1 was adjusted to 3.16% by mass.
(preparation of light-emitting particle Dispersion 12)
Light-emitting particle dispersion liquid 8 was obtained in the same manner as light-emitting particle dispersion liquid 4 except that phenoxyethyl methacrylate was used as the photopolymerizable compound instead of isobornyl methacrylate.
(preparation of light-emitting particle Dispersion 13)
First, 0.12g of cesium carbonate, 5mL of 1-octadecene, and 0.5mL of oleic acid were mixed to obtain a mixed solution. Then, the mixture was dried at 120 ℃ for 30 minutes under reduced pressure, and then heated at 150 ℃ under an argon atmosphere. Thereby, a cesium-oleic acid solution was obtained.
On the other hand, 0.1g of lead (II) bromide, 7.5mL of 1-octadecene, and 0.75mL of oleic acid were mixed to obtain a mixed solution. Then, the mixture was dried at 90 ℃ for 10 minutes under reduced pressure, and 0.75mL of 3-aminopropyltriethoxysilane was added to the mixture under an argon atmosphere. Then, the mixture was further dried under reduced pressure for 20 minutes, and then heated at 140 ℃ under an argon atmosphere.
Then, 0.75mL of the cesium-oleic acid solution was added to the mixed solution containing lead (II) bromide at 150 ℃, and the mixture was stirred for 5 seconds to react, followed by cooling in an ice bath. Next, 60mL of methyl acetate was added. After the obtained suspension was subjected to centrifugal separation (10,000 rpm, 1 minute), the supernatant was removed, thereby obtaining a solid containing the precursor particles P1. The nanocrystals constituting the precursor particles P1 were perovskite-type cesium lead tribromide crystals, and analyzed by scanning transmission electron microscope observation, and the average particle diameter thereof was 10nm. 800mg of a block copolymer having a structure represented by the following formula (B3) (S2 VP, manufactured by Polymer Source) as a polymer B was added to 80mL of toluene, and dissolved by heating at 60 ℃. To the solid material containing the precursor particles P1, 80mL of toluene in which the block copolymer was dissolved was added, and after stirring for 15 minutes, centrifugal separation was performed to recover the supernatant, thereby obtaining a toluene dispersion containing the precursor particles and the block copolymer.
Figure BDA0004092365490000971
To 2mL of the toluene dispersion, 10. Mu.L of a compound represented by the following formula (C4) (MS-51, manufactured by COLCOAT corporation, average value of m in formula (C4) is 4) was added and stirred for 5 minutes, and then 5. Mu.L of ion-exchanged water was further added and stirred for 2 hours.
Figure BDA0004092365490000972
The obtained solution was centrifuged at 9,000 rpm for 5 minutes, and 2mL of the supernatant was collected to obtain a light-emitting particle dispersion T in which light-emitting particles were dispersed in toluene. The average particle diameter of the luminescent particles dispersed in the luminescent particle dispersion T was measured by using a dynamic light scattering Nanotrac particle size distribution meter, and the result was 109nm. The element distribution of the light-emitting particles was evaluated by energy dispersive X-ray spectroscopy (STEM-EDS) using a scanning transmission electron microscope, and it was confirmed that Si was contained in the surface layer. In addition, the thickness of the surface layer was 49nm.
Toluene was removed from the luminescent particle dispersion T, thereby obtaining 0.20 parts by mass of a silica-coated perovskite-type cesium lead tribromide crystal as the luminescent particle X-7. Then, the obtained light-emitting particles X-7 were dispersed in phenoxyethyl acrylate so that the solid content concentration became 2.5 mass%, thereby obtaining a light-emitting particle dispersion liquid 13.
In table 1 below, the obtained light-emitting particle dispersions 1 to 13 show the dispersoid, the presence or absence of the inorganic coating layer in the dispersoid, and the presence or absence of the polymer layer.
[ Table 1]
Luminescent particle dispersion Dispersoid Inorganic coating layer Polymer layer
Luminescent particle dispersion 1 Luminescent particle X-1 Hollow nano-silica particles Is free of
Light-emitting particle dispersion liquid 2 Polymer-coated luminescent particle X-2 Hollow nano-silica particles Is provided with
Luminescent particlesDispersion 3 Luminescent particle X-3 Hollow nano-silica particles Is free of
Luminescent particle dispersion liquid 4 Luminescent particles X-4 Siloxane bond layer Is free of
Light-emitting particle dispersion 5 Polymer-coated luminescent particle X-5 Siloxane bond layer Is provided with
Luminescent particle dispersion liquid 6 Luminescent particle X-6 Is free of Is composed of
Light-emitting particle dispersion liquid 7 Luminescent particle X-1 Hollow nano-silica particles Is free of
Luminescent particle dispersion liquid 8 Luminescent particle X-4 Siloxane bond layer Is free of
Luminescent particle dispersion liquid 9 Luminescent particle X-1 Hollow nano-silica particles Is composed of
Light-emitting particle dispersion liquid 10 Luminescent particles X-1 Hollow nano-silica particles Is free of
Light-emitting particle dispersion liquid 11 Luminescent particle X-1 Hollow nano-silica particles Is free of
Light-emitting particle dispersion 12 Luminescent particle X-4 Siloxane bond layer Is free of
Light-emitting particle dispersion liquid 13 Luminescent particle X-7 Siloxane bond layer Is free of
< preparation of light diffusing particle Dispersion >
(preparation of light-diffusing particle Dispersion 1)
In a vessel filled with nitrogen gas, 10.0 parts by mass of titanium oxide ("CR 60-2" manufactured by Shigaku Kogyo Co., ltd.), 1.0 part by mass of a polymer dispersant "Efka PX4701" (amine value: 40.0mgKOH/g, manufactured by BASF Japan Co., ltd.), and 14.0 parts by mass of phenoxyethyl methacrylate (Lightester PO; manufactured by Kyoto chemical Co., ltd.) were mixed. Further, zirconia beads (diameter: 1.25 mm) were added to the obtained complex, the above vessel was closed, and dispersion treatment of the complex was performed by shaking for 2 hours using a paint shaker, thereby obtaining a light-diffusing particle dispersion 1. The average particle diameter of the light-diffusing particles after the dispersion treatment was 0.245 μm as measured using NANOTRAC WAVE II.
(preparation of light-diffusing particle Dispersion 2)
A light-diffusing particle dispersion 2 was obtained in the same manner as in the light-diffusing particle dispersion 1 except that "Afka PX4701" was used as the polymer dispersant in place of "Efka PX4701" by "Ajisper PB821" (amine value: 10mgKOH/g, acid value: 17mgKOH/g, ajinomoto Fine-Technio Co., ltd.). The average particle diameter of the light-diffusing particles after dispersion treatment was measured using NANOTRAC WAVE II, and was 0.315. Mu.m.
(preparation of light-diffusing particle Dispersion 3)
A light-diffusing particle dispersion liquid 3 was obtained in the same manner as the light-diffusing particle dispersion liquid 1 except that "DISPERBYK-111" (acid value: 129mgKOH/g, manufactured by BYK-Chemie Japan K.K.) was used as the polymer dispersant in place of "Efka PX 4701". The average particle diameter of the light-diffusing particles after the dispersion treatment was measured using NANOTRAC WAVE II, and found to be 0.550. Mu.m.
(preparation of light-diffusing particle Dispersion 4)
In a vessel filled with nitrogen, 10.0 parts by mass of titanium oxide ("CR 60-2" manufactured by Shigaku corporation) and 14.0 parts by mass of phenoxyethyl methacrylate (Lightester PO; manufactured by Kyoeisha chemical Co., ltd.) were mixed. Further, zirconia beads (diameter: 1.25 mm) were added to the obtained complex, the above vessel was closed, and dispersion treatment of the complex was performed by shaking for 2 hours using a paint shaker, thereby obtaining a light-diffusing particle dispersion 4. The light diffusion particle dispersion 4 does not contain a polymer dispersant. The average particle diameter of the light-diffusing particles after the dispersion treatment was measured using NANOTRAC WAVE II, and was 0.855. Mu.m.
< preparation of ink composition containing luminescent particles >
(preparation of luminescent particle-containing ink composition (1))
6.0 parts by mass of luminescent particle dispersion 1 (luminescent particle concentration: 2.5% by mass), 0.75 parts by mass of light diffusing particle dispersion 1 (titanium oxide content: 40.0% by mass), 2.0 parts by mass of "lauryl methacrylate" (product name: lightester LM, manufactured by Kyoto chemical Co., ltd.) and "1, 6-hexanediol dimethacrylate" (product name: lightester 1,6-HX, manufactured by Kyoto chemical Co., ltd.) as photopolymerizable compounds, 0.3 parts by mass of "diphenyl- (2, 4, 6-trimethylbenzoyl) phosphine oxide" (product name: omnirad TPO-H, manufactured by BASF Japan K.K.) as photopolymerization initiator, 0.3 parts by mass of "phenylbis (2, 4, 6-trimethylbenzoyl) phosphine oxide" (product name: omnirad, manufactured by BASF Japan K.K., 0.1.1 part by mass of "phenyl bis (2, 4, 6-trimethylbenzoyl) phosphine oxide" (product name: omnirad, 0.1.1.1 part by mass of BASF Japan K., 0.10 parts by mass of "bis (2, 4, 6-tert-butyl) phosphine oxide" (product: adenox) as antioxidant, and 0.5 parts by mass of "bis (Adenoxas-5-2, 6-butyl-2-5-2,10 parts by mass of" Adenoxas "(product) as antioxidant, 2,10, 6-bis (Adenoxas) as photopolymerization initiator, after the uniform dissolution, the dissolved matter was filtered through a filter having a pore size of 5 μm in a glove box. Further, argon gas was introduced into the vessel containing the obtained filtrate, and the inside of the vessel was saturated with argon gas. Then, the pressure was reduced to remove the argon gas, thereby obtaining an ink composition (1) containing luminescent particles. The content of luminescent particles was 1.5% by mass, the content of IB-X was 58.5% by mass, the content of LM was 6.5% by mass, the content of PO was 4.2% by mass, the content of 1,6-HX was 20.0% by mass, the content of TPO-H was 3.0% by mass, the content of 819 was 1.0% by mass, the content of Irganox1010 was 1.0% by mass, the content of PEP-36 was 1.0% by mass, the content of light-scattering particles was 3.0% by mass, and the content of polymeric dispersant was 0.3% by mass. The content is based on the total mass of the ink composition.
(preparation of luminescent particle-containing ink compositions (2) to (37) and (C1) to (C5))
The light-emitting particle-containing ink compositions (2) to (37) of examples 2 to 37 and the light-emitting particle-containing ink compositions (C1) to (C5) of comparative examples 1 to 5 were obtained under the same conditions as in the preparation of the light-emitting particle-containing ink composition (1) except that the addition amounts of the light-emitting particle dispersions 1 to 11, the light-diffusing particle dispersions 1 to 4, the photopolymerizable compounds D-1 to D-8, the photopolymerization initiators E-1 to E-4, the first antioxidants (a) a-1 to a-3, the second antioxidants (B) B-1 to B-4, and the light stabilizers H-1 to H-4 were changed to the addition amounts shown in tables 2 to 6 below.
Further, the ratio (a/B) of the antioxidant a to the antioxidant B used in the ink composition containing the light-emitting particles, the mass ratio (Mc/M) of the photopolymerizable compound (Mc) having a cyclic structure in the total amount of the photopolymerizable compound (M), and the content M of the radical polymerizable compound having a linear structure with 3 or more carbon atoms are shown in the following tables 7 and 8 L Content M of the radical polymerizable Compound having a Cyclic Structure C Mass ratio (M) of L /M C )。
[ Table 2]
Figure BDA0004092365490001011
[ Table 3]
Figure BDA0004092365490001021
[ Table 4]
Figure BDA0004092365490001031
[ Table 5]
Figure BDA0004092365490001041
[ Table 6]
Figure BDA0004092365490001051
[ Table 7]
Figure BDA0004092365490001061
[ Table 8]
Figure BDA0004092365490001071
(first antioxidant A)
Figure BDA0004092365490001072
Compound (A-1): "tetrakis [ methylene-3 (3 ',5' -di-t-butyl-4 ' -hydroxyphenyl) propionate ] methane" (product name: IRGANOX 1010, melting point 110-130 ℃, molecular weight 1178, manufactured by BASF Japan K.K.)
Compound (A-2): "3, 9-bis [2- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy ] -1, 1-dimethylethyl ] -2,4,8, 10-tetraoxaspiro [5.5] undecane" (product name: adekastab AO-80, melting point 110 to 120 ℃, molecular weight 741, manufactured by ADEKA Co., ltd.)
Compound (A-3): "Butylhydroxytoluene" (product name: ANTAGE BHT, melting point 70 ℃, molecular weight 220, available from Karman chemical industry Co., ltd.)
(second antioxidant B)
Figure BDA0004092365490001081
Compound (B-1): "3, 9-bis (2, 6-di-t-butyl-4-methylphenoxy) -2,4,8, 10-tetraoxa-3, 9-diphosphaspiro [5.5] undecane" (product name: adekastab PEP-36, melting point 237 ℃, molecular weight 633, manufactured by ADEKA Co., ltd.)
Compound (B-2): "Tris (2, 4-di-tert-butylphenyl) phosphite" (product name: adekastab 2112, melting point 183 ℃, molecular weight 647, manufactured by ADEKA K.K.)
Compound (B-3): "2,4,8,10-tetrakis (1, 1-dimethylethyl) -6- [ (2-ethylhexyl) oxy ] -12H-dibenzo [ d, g ] [1,3,2] dioxaphosph-ocine" (product name: adekastab HP-10, melting point 148 ℃, molecular weight 583, manufactured by ADEKA Co., ltd.)
Compound (B-4): "Triphenyl phosphite" (product name: JP-360, melting point 25 ℃, molecular weight 310, made by Tokyo chemical industry Co., ltd.)
(photopolymerizable Compound)
Compound (D-1): "isobornyl methacrylate" (product name: lightester IB-X, manufactured by Kyoeisha chemical Co., ltd.)
Compound (D-2): "lauryl methacrylate" (product name: lightester L, kyoeisha chemical Co., ltd.)
Compound (D-3): "phenoxyethyl methacrylate" (product name: lightester PO, kyoeisha chemical Co., ltd.)
Compound (D-4): "1, 6-hexanediol dimethacrylate" (product name: lightester 1,6-HX, kyoeisha chemical Co., ltd.)
Compound (D-5): "1, 6-hexanediol diacrylate" (product name: light acrylate 1,6-HX-A, co., ltd.; manufactured by Kyoeisha chemical Co., ltd.)
Compound (D-6): "neopentyl glycol diacrylate" (product name: light acrylate NP-A, manufactured by Kyoeisha chemical Co., ltd.)
Compound (D-7): "PO-modified Glycerol triacrylate" (product name: OTA480, manufactured by DAICEL-ALLNEX Co., ltd.)
Compound (D-8): "Di (trimethylolpropane) tetraacrylate" (product name: LUMICURE DTA-400S, manufactured by Toyo Synthesis Co., ltd.)
(photopolymerization initiator)
Compound (E-1): "Diphenyl- (2, 4, 6-trimethylbenzoyl) phosphine oxide" (product name: omnirad TPO-H, monoacylphosphine oxide-based Compound, manufactured by IGM RESINS Co., ltd.)
Compound (E-2): "Ethyl phenyl- (2, 4, 6-trimethylbenzoyl) phosphinate" (product name: omnirad TPO-L, monoacylphosphine oxide compound, manufactured by IGM RESINS Co., ltd.)
Compound (E-3): "Phenylbis (2, 4, 6-trimethylbenzoyl) phosphine oxide" (product name: omnirad 819, bisacylphosphine oxide-based Compound, manufactured by IGM RESIN Co., ltd.)
Compound (E-4): "2, 2-dimethoxy-2-phenylacetophenone" (product name: omnirad 651, acetophenone-based compound, manufactured by IGM RESINS Co., ltd.)
(light stabilizer)
Compound (H-1): adekastab LA63P (product name, manufactured by ADEKA K.K., functional group equivalent: 269)
Compound (H-2): tinuvinNOR371FF (product name, manufactured by BASF Japan K.K., functional group equivalent: 350)
Compound (H-3): adekastab LA72 (product name, manufactured by ADEKA corporation, functional group equivalent: 255)
Compound (H-4): adekastab LA52 (product name, manufactured by ADEKA K.K., functional group equivalent: 212)
< evaluation of ink composition containing luminescent particles >
(example 1)
(stability of ink viscosity)
The viscosity stability of the ink composition (1) containing luminescent particles of the present invention was evaluated by the following method. The viscosity of the ink composition immediately after the preparation was compared with the viscosity of the ink composition stored in a thermostatic bath at 40 ℃ for 1 week after the preparation, and the rate of increase in viscosity was calculated. Specifically, the viscosity of the ink composition immediately after preparation is defined as η 0 The viscosity of the ink composition stored in a thermostatic bath at 40 ℃ for 1 week after the preparation was defined as eta 1 The calculation was performed by the following formula, and the result was 0.11%.
Viscosity increase rate (%) = (η) 1 -η 0 )/η 0 ×100
(Dispersion stability)
After the light-emitting particle-containing ink composition (1) of the present invention was left to stand in the atmosphere for 10 days, the presence or absence of the precipitate on the bottom surface of the container was visually confirmed, and as a result, no precipitate was formed at all.
[ evaluation standards ]
A: no precipitate was produced at all.
B: very little precipitate was produced. The precipitate was dissolved by shaking.
C: more precipitate was generated. Even with shaking, the precipitate remained.
D: many precipitates were produced, and the precipitates were distinct from the liquid component. Even with shaking, the precipitate remained.
(examples 2 to 30)
The initial viscosities, viscosity stabilities, and dispersion stabilities of the ink compositions (2) to (37) containing luminescent particles of the present invention were evaluated in the same manner as in example 1 using the ink compositions (2) to (37) containing luminescent particles.
Comparative examples 1 to 6
The initial viscosity, viscosity stability, and dispersion stability of the ink compositions (C1) to (C6) containing luminescent particles were evaluated in the same manner as in example 1, using the ink compositions (C1) to (C6) containing luminescent particles for comparison.
The results are shown in tables 9 and 10.
[ Table 9]
Figure BDA0004092365490001111
[ Table 10]
Figure BDA0004092365490001121
< evaluation of light conversion layer >
(example 31)
The light-emitting particle-containing ink composition (1) of the present invention was applied to glass by a spin coater in the air so that the dried film thickness became 15 μmOn the substrate. Under a nitrogen atmosphere, the total quantity of light was 10J/cm by a UV irradiation apparatus using an LED lamp having a main wavelength of 395nm 2 After the coating film was cured by UV irradiation, the coating film was heated at 180 ℃ for 30 minutes in a glove box having an oxygen concentration of 1 vol% or less, to form a layer composed of a cured product of the ink composition on a glass substrate, and this was used as the light conversion layer 1. Thus, the surface smoothness and external quantum efficiency retention rate of the light conversion layer were evaluated.
(film curing Property)
The surface of the obtained light-converting layer 1 was evaluated by palpation with a cotton swab based on the following criteria, and as a result, the surface of the coating film was not damaged, and a slight sticky feeling was observed, which was a level not problematic in practical use.
[ evaluation standards ]
Very good: no damage to the surface of the coating
O: the coating film surface was not damaged and had a slight sticky feeling, but was at a level not problematic in practical use
And (delta): the surface of the coating film was slightly damaged and had a sticky feeling
X: the surface of the coating film was damaged, and a part of the cured film was adhered to the cotton swab
(evaluation of surface smoothness)
The surface roughness (Sa value; unit. Mu.m) of the obtained light conversion layer 1 was measured using VertScan3.0R4300 of Ryoka Systems, and found to be 0.07. Mu.m.
(evaluation of External Quantum Efficiency (EQE))
An integrating sphere was placed above a blue LED (peak emission wavelength: 450 nm) manufactured by CCS co, a surface-emitting light source, and a radioactive spectrophotometer (trade name "MCPD-9800") manufactured by tsukamur electronics co was connected to the integrating sphere. Next, the evaluation sample 1 was inserted between the blue LED and the integrating sphere, the blue LED was turned on, and the observed spectrum and illuminance at each wavelength were measured by an emission spectrophotometer. From the obtained spectrum and illuminance, the External Quantum Efficiency (EQE) was obtained as follows.
The external quantum efficiency is a value indicating how much of the light (photons) incident on the light conversion layer is emitted as fluorescence to the observer side. Therefore, the larger this value, the more excellent the light emission characteristics of the light conversion layer, and this value is an important evaluation index. The External Quantum Efficiency (EQE) is calculated by the following formula (1).
EQE[％]＝P2/E(Blue)×100 (1)
In the formula, E (Blue) represents the total value of "illuminance X wavelength/hc" in the wavelength region of 380 to 490nm, and P2 represents the total value of "illuminance X wavelength/hc" in the wavelength region of 500 to 650nm, which are values corresponding to the number of observed photons. It should be noted that h represents a planck constant, and c represents a light speed.
Then, EQE measured immediately after the light conversion layer 1 was fabricated was set as initial external quantum efficiency EQE 0 For EQE 0 The measurement was carried out, and the result was 32%. Then, the light conversion layer 1 was stored at 80 ℃ under the atmosphere for 1 week. The external quantum efficiency after storage is set as EQE h The external quantum efficiency holding ratio EQE of the light conversion layer was calculated by the following formula (2) HT [％]。
EQE HT [％]＝EQE h /EQE 0 ×100 (2)
Here, EQE 0 The larger the numerical value (c) is, the smaller the deterioration of the semiconductor nanocrystal by ultraviolet rays in the curing step of the coating film is, that is, the more excellent the stability against ultraviolet rays is. For use as light-converting layers, EQE 0 Preferably 20% or more, more preferably 25% or more, means excellent. Further, the light conversion layer is preferably EQE eliminating 0 In addition, further EQE h Also higher, external quantum efficiency retention rate EQE HT Higher means that the light conversion layer containing the luminescent particles has higher stability to oxygen and water vapor.
(evaluation of light resistance of coating film)
The light conversion layer 1 was continuously irradiated with LED light at 50 ℃ for 1 week. The external quantum efficiency after irradiation was defined as EQE u The external quantum efficiency holding ratio EQE of the light conversion layer was calculated by the following formula (3) UV [％]。
EQE UV [％]＝EQE u /EQE 0 ×100 (3)
The light conversion layer is preferably EQE 0 In addition, further EQE u And is also higher. External quantum efficiency maintenance rate EQE of light conversion layer UV Higher means more excellent light resistance at high temperatures.
(examples 39 to 74)
Using the ink compositions (2) to (37) containing luminescent particles of the present invention, the surface roughness Sa (μm) and EQE of the photoconversion layers 1 to 37 were measured in the same manner as in example 38 0 (％)、EQE HT (%) and EQE UV (%) was evaluated.
Comparative examples 7 to 12
The surface roughness Sa (μm) and EQE of the photoconversion layers C1 to C6 were measured in the same manner as in example 38 using comparative ink compositions (C1) to (C6) containing luminescent particles 0 (%) and EQE HT (%) and EQE UV (%) was evaluated.
The results are shown in tables 11 and 12.
[ Table 11]
Figure BDA0004092365490001151
[ Table 12]
Figure BDA0004092365490001161
< evaluation results of ink composition containing luminescent particles and light conversion layer >
First, the ink compositions containing luminescent particles of examples 1 to 11 and comparative examples 1 to 6, and the light conversion layers of examples 38 to 48 and comparative examples 7 to 11 produced using them were examined. The light-emitting particle-containing ink composition of comparative example 1 used only 1 kind of photopolymerization initiator and contained no antioxidant, and therefore did not suppress the increase in viscosity of the ink with time, and the EQE of the light-converting layer of comparative example 7 HT And EQE UV Lower. In comparative examples 2 to 4 and 6, although the antioxidant was contained, the antioxidant was addedSince only 1 kind of photopolymerization initiator was used in a large amount, the initial viscosity of the ink was high, and the increase in viscosity with time could not be suppressed, and in the light conversion layers of comparative examples 8 to 10 and 12, the curability was poor and the surface of the coating film was rougher, and EQE HT And EQE UV Lower. Further, the light-emitting particle-containing ink composition of comparative example 5 used only 1 kind of photopolymerization initiator and used a very small amount of 0.5 mass%, and the ink viscosity was suppressed to be low, but when the light conversion layer of comparative example 11 was formed, sufficient curability was not obtained, and the ink composition had no performance as a light conversion layer.
On the other hand, the light-emitting particle-containing ink compositions of examples 1 to 6 were reduced in the total amount of use by using 2 types of photopolymerization initiators, and had low initial viscosity of the ink and suppressed thickening with time due to the inclusion of the first antioxidant and the second antioxidant, and also had curability, surface roughness, and EQE when prepared into the light-converting layers of examples 38 to 43 HT And EQE UV It was also good. Further, the light-emitting particle-containing ink compositions of examples 7 to 11 were reduced in the amount of the whole used by using 2 kinds of photopolymerization initiators, and further reduced in the initial viscosity of the ink and suppressed in thickening with time because the first antioxidant and the second antioxidant were contained in smaller and appropriate amounts, and further cured, surface roughness, and EQE when the light-converting layers of examples 44 to 48 were prepared HT And EQE UV It was also good. As is clear from the above, the light-emitting particle-containing ink compositions of examples 1 to 11 can maintain the viscosity and dispersion stability of the ink suitable for ink jet as compared with comparative examples 1 to 4, and can form a smooth light-converting layer having no problem in curability when formed into a coating film having excellent light-emitting characteristics while ensuring excellent stability against oxygen, water vapor and heat.
Next, the ink compositions containing the light-emitting particles of examples 1 and 12 to 15 and the light-converting layers of examples 38 and 49 to 52 produced using them were examined. The ink compositions of examples 1, 12 to 15 used light-emitting particles having a silica coating layer on the surface, examples 12 and 15The ink composition of (3) uses luminescent particles further coated with a polymer layer. These ink compositions were excellent in stability of ink viscosity and dispersion stability, and the light-converting layers of examples 49 and 52 were good in curability, small in surface roughness, and EQE HT And EQE UV Also, the most excellent characteristics were obtained particularly when the luminescent particles used in the ink composition of example 15 were contained. As is clear from the above, when 2 kinds of photopolymerization initiators were used and the first antioxidant and the second antioxidant were contained, excellent characteristics were obtained by using the light-emitting particles coated with the silica layer and the polymer layer.
Next, the ink compositions containing the light-emitting particles of examples 7, 17, and 19, and the light conversion layers of examples 44, 54, and 56 produced using them were examined. These ink compositions contain polymerizable compounds having different structures, specifically, compounds having a cyclic structure and compounds having a chain structure. The ink compositions of examples 7 and 17 containing a large amount of the photopolymerizable compound having a cyclic structure were excellent in ink viscosity stability and dispersion stability, and the light conversion layers of examples 44 and 54 were excellent in curability, surface roughness, and EQE HT And EQE UV It was also good. On the other hand, it is clear that the ink composition of example 19 is slightly inferior in ink viscosity stability and dispersion stability, and the EQE of the light conversion layer of example 56 HT And EQE UV It was also slightly inferior, but at a level that was not problematic in practical use. As is clear from the above, increasing the proportion of the photopolymerizable compound having a cyclic structure in the photopolymerizable compound in the ink composition containing the light-emitting particles results in excellent ink characteristics and light conversion layer characteristics.
Further, the ink compositions containing luminescent particles of examples 19 to 25 and the light conversion layers of examples 56 to 62 produced using them were examined. It is known that, although the types of 2-or more-functional photopolymerizable compounds which function as crosslinking components are different in these ink compositions, the stability of ink viscosity and dispersion stability are found in the case of either composition when the first antioxidant a and the second antioxidant B are containedExcellent in qualitative property and curing property, surface roughness and EQE of light conversion layer HT And EQE UV Is excellent and therefore is practically free from problems.
Next, the ink compositions containing luminescent particles of examples 19 and 26 to 28 and comparative example 4, and the light conversion layers of examples 56 and 63 to 65 and comparative example 10 produced using them were examined. The ink compositions of examples 19 and 26 to 28 each contain 2 or more types of acylphosphine oxide-based compounds and the first antioxidant a and the second antioxidant B, and the compositions containing only the acylphosphine oxide-based compound are particularly preferable since they are excellent in the stability of viscosity and dispersion stability of the ink in any ink composition, and also excellent in curability, surface roughness, and EQE retention rate of the photoconversion layers of examples 56 and 63 to 65, although the types and the amounts of the photopolymerization initiators are different. On the other hand, in the ink composition of comparative example 4, although the photopolymerization initiator containing only 1 acylphosphine oxide-based compound was contained in a large amount in order to impart a certain degree of curability, as a result, even if the first and second antioxidants were contained, the ink viscosity and dispersion stability were inferior, and the characteristics of the light conversion layer of comparative example 10 were inferior. From the above, it is important to contain 2 kinds of photopolymerization initiators to ensure solubility in the ink composition.
Further, the ink compositions containing luminescent particles of examples 19, 29 to 30 and comparative example 6, and the light conversion layers of examples 56, 66 to 67 and comparative example 12 produced using them were examined. The ink compositions of examples 19 and 29 to 30 contained different polymeric dispersants, and the ink composition of comparative example 6 contained 1 photopolymerization initiator and no polymeric dispersant. The ink compositions of examples 19 and 29 to 30 contained polymer dispersants having different amine values and acid values. According to these evaluation results, the ink composition containing the polymeric dispersant having an amine value exhibited good dispersion stability of the light-scattering particles and the light-emitting particles. It is found that the polymer dispersant having an amine value alone has very excellent dispersion stability. In the ink composition of example 30, in which the dispersion stability of the ink was slightly poor, the surface roughness of the light conversion layer of example 67 was slightly poor. From the above, it is known that it is important for the ink composition to have excellent dispersion stability in order to obtain a flat light conversion layer. These ink compositions are at a level that causes no problem in practical use. On the other hand, the ink composition of comparative example 6, which contained 1 kind of photopolymerization initiator and no polymeric dispersant, exhibited a significantly high initial viscosity, very poor viscosity stability, and poor dispersion stability. Therefore, it is clear that the light conversion layer of comparative example 12 is also very poor in each characteristic and cannot be used practically.
Next, the ink compositions containing the light-emitting particles of examples 31 to 37 and the light-converting layers of examples 68 to 74 produced using them were examined. The ink composition of example 31 used light-emitting particles having a silica coating layer on the surface. The ink composition was excellent in stability of ink viscosity and dispersion stability, and the light-converting layer of example 68 was good in curability, small in surface roughness, and EQE HT And EQE UV Also excellent. In addition, the ink compositions of examples 32 and 33 used light-emitting particles having a silica layer thicker than the surface, and the ink was excellent in stability of viscosity and dispersion stability, and the light-converting layers of examples 69 and 70 were extremely excellent in curability, and EQE HT And EQE UV Also excellent in the properties. Further, the ink compositions of examples 34 to 37, which used a light stabilizer, were excellent in stability of ink viscosity and dispersion stability, and the light-converting layers of examples 71 to 74 were excellent in curability and EQE HT And EQE UV Is extremely excellent. From the above, it is clear that the use of the light-emitting particles coated with the silica layer imparts excellent characteristics.
From the above, it is clear that the light conversion layers of examples 38 to 74 obtained by the ink compositions containing the luminescent particles of examples 1 to 37 are excellent in the light emission characteristics and have smooth surfaces. Therefore, it is expected that excellent light emission characteristics can be obtained when the color filter pixel portion of the light emitting element is configured using these light conversion layers.
Description of the symbols
100: a light emitting element; 200: an EL light source unit; 1: a lower substrate; 2: an anode; 3: a hole injection layer; 4: a hole transport layer; 5: a light emitting layer; 6: an electron transport layer; 7: an electron injection layer; 8: a cathode; 9: a sealing layer; 10: a filling layer; 11: a protective layer; 12: a light conversion layer; 13: an upper substrate; 14: an EL layer; 20: a pixel section; 20a: a 1 st pixel section; 20b: a 2 nd pixel section; 20c: a 3 rd pixel section; 21a: 1 st light diffusing particle; 21b: 2 nd light diffusing particles; 21c: 3 rd light diffusing particles; 22a: 1, curing the components; 22b: a 2 nd curing component; 22c: a 3 rd curing component; 90a: 1 st luminescent particle; 90b: 1 st luminescent particle; 30: a light shielding portion; 90: light-emitting particles, polymer-coated particles; 91: a light-emitting particle; 911: a nanocrystal; 912: hollow nanoparticles; 912a: a hollow part; 912b: fine pores; 913: an intermediate layer; 914: a surface layer; 92: a polymer layer; 701: a capacitor; 702: a drive transistor; 705: a common electrode; 706: a signal line; 707: scanning a line; 708: a switching transistor; c1: a signal line drive circuit; c2: a scanning line driving circuit; c3: a control circuit; PE, R, G, B: a pixel electrode; x: a copolymer; XA: an association body; x1: an aliphatic polyamine chain; x2: a hydrophobic organic segment; YA: core-shell silica nanoparticles; z: a solution containing a starting compound for semiconductor nanocrystals.

Claims (17)

1. An ink composition containing luminescent particles, comprising: nanoparticles comprising a semiconductor nanocrystal comprising a metal halide and having a light-emitting property, a photopolymerizable compound, a photopolymerization initiator, and an antioxidant,
the photopolymerization initiator contains 2 or more types of acylphosphine oxide compounds,
the antioxidant contains 1 or more compounds selected from the group consisting of a compound having a hydroxyphenyl group and a compound having a phosphite structure.
2. The light-emitting particle-containing ink composition according to claim 1, wherein the content of the photopolymerization initiator is 1 to 15% by mass.
3. The ink composition containing luminescent particles according to claims 1 and 2, characterized in that the antioxidant comprises: a first antioxidant A comprising at least 1 or more compounds having a hydroxyphenyl group; and a second antioxidant B comprising at least 1 or more compounds having a phosphite structure.
4. The light-emitting particle-containing ink composition according to claim 3, wherein the mass ratio A/B of the second antioxidant B to the first antioxidant A is 0.05 to 5.0.
5. The light-emitting particle-containing ink composition according to any one of claims 1 to 4, wherein the compound having a hydroxyphenyl group contained in the first antioxidant A or the compound having a phosphite structure contained in the second antioxidant B has a molecular weight of 500 to 1500, and a softening point and a melting point of 70 ℃ to 250 ℃.
6. The ink composition containing luminescent particles according to any one of claims 1 to 5, wherein the first antioxidant A contains 1 or 2 or more compounds represented by the general formula (I),
Figure FDA0004092365480000011
in the formula (I), M 1 Represents 1, 4-phenylene, trans-1, 4-cyclohexylene, 2,4,8, 10-tetraoxaspiro [5,5 ]]Undecyl, a C1-20 hydrocarbon group, 1 or 2 or more-CH in the hydrocarbon group 2 May be substituted by-O-insofar as the oxygen atoms are not directly adjacent-CO-, -COO-, -OCO-, -NH-, any hydrogen atom in the hydrocarbon group may be substituted with a substituted phenyl group,
X 1 represents an alkylene group having 1 to 15 carbon atoms or-OCH 2 -、-CH 2 O-, -COO-, -OCO-, -CH = CH-COO-, -CH = CH-OCO-, -COO-CH = CH-, -OCO-CH = CH-, -C.ident.C-, a single bond, 1, 4-phenylene or trans-1, 4-cyclohexylene, which may be the same or different from each other, 1 or 2 or more-CH in the alkylene group 2 <xnotran> - -O-, -CO-, -COO-, -OCO-,1,4- 1 ～ 6 , </xnotran>
R 11 And R 12 Each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms,
k represents an integer of 2 to 6.
7. The light-emitting particle-containing ink composition according to any one of claims 1 to 5, wherein the second antioxidant B contains 1 or 2 or more compounds represented by the general formula (II) or the general formula (III),
Figure FDA0004092365480000021
in the general formula II, R 20 To R 24 Each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, one of the methyl groups in the alkyl group being substituted with an aryl group;
Figure FDA0004092365480000022
in the formula (III), R 30 To R 37 Each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms,
R 3a 、R 3b each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, or R 3a And R 3b A ring structure is formed, and the ring structure,
Z 31 represents a straight-chain alkyl group or aryl group having 1 to 10 carbon atoms, any hydrogen atom of the aryl group may be replaced by a straight-chain alkyl group having 1 to 6 carbon atomsOr branched alkyl substitution.
8. The luminescent particle-containing ink composition according to any one of claims 1 to 7, wherein the semiconductor nanocrystal is a compound having a perovskite crystal structure.
9. The light-emitting particle-containing ink composition according to any one of claims 1 to 8, wherein the nanoparticles containing the semiconductor nanocrystals are provided with an inorganic coating layer made of an inorganic material on the particle surface.
10. The light-emitting particle-containing ink composition according to claim 9, comprising a resin coating layer made of a resin for coating the surface of the nanoparticles comprising the semiconductor nanocrystals, the surface being provided with an inorganic coating layer.
11. The light-emitting particle-containing ink composition according to any one of claims 1 to 10, wherein the photopolymerizable compound contains 2 or more monomers selected from the group consisting of a monofunctional (meth) acrylate monomer and a multifunctional (meth) acrylate monomer.
12. The light-emitting particle-containing ink composition according to claim 11, wherein at least 1 of the 2 or more monomers contained in the photopolymerizable compound is a (meth) acrylate monomer having a cyclic structure.
13. The light-emitting particle-containing ink composition according to any one of claims 1 to 12, further comprising light-diffusing particles.
14. The light-emitting particle-containing ink composition according to claim 13, further comprising a polymeric dispersant.
15. The luminescent particle-containing ink composition according to any one of claims 1 to 14, which is used in an inkjet manner.
16. A light conversion layer having a pixel portion,
the pixel portion includes a cured product of the light-emitting particle-containing ink composition according to any one of claims 1 to 15.
17. A light-emitting element comprising the light-converting layer according to claim 16.
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