KR20240099032A - Dispersion, composition comprising said dispersion and light conversion layer - Google Patents

Abstract

[Problem] To provide a dispersion containing luminescent particles containing nanocrystals with little change in luminescence properties and excellent long-term storage, a composition containing the dispersion, and a light conversion layer formed from the composition.
[Solution] A dispersion containing luminescent particles having a surface layer containing a structure having a siloxane bond on the surface of a semiconductor nanocrystal made of metal halide, and having a moisture content of 0.10% or more and 1.0% or less.

Description

Dispersion, composition containing the dispersion, and light conversion layer {DISPERSION, COMPOSITION COMPRISING SAID DISPERSION AND LIGHT CONVERSION LAYER}

The present invention relates to a dispersion containing luminescent particles, a composition containing the dispersion, and a light conversion layer made of the composition.

As a light-emitting material that satisfies the international standard BT.2020 required for next-generation display devices, semiconductor nanocrystals are attracting attention. For example, luminescent nanocrystals such as quantum dots, quantum rods, and other inorganic phosphor particles can be used to emit red light or Display devices and lighting devices using light conversion sheets that extract green light, light conversion layers such as color filter pixels, and luminescent nanocrystals as backlights have been proposed.

Luminescent nanocrystals have the characteristic of emitting fluorescence or phosphorescence and having a narrow half width of the emission spectrum. In the currently mainstream core-shell quantum dots, CdSe and the like were initially used, but in order to avoid the harmful effects of Cd, InP and the like have been used recently. However, its stability as a particle is low, and studies to improve its stability are actively progressing. In addition, since the emission wavelength of core-shell quantum dots is determined by the particle size, the dispersion of the particle diameters needs to be precisely controlled in order to obtain emission with a narrower half width, and there are many challenges in producing them.

Meanwhile, quantum dots with a perovskite-type crystal structure have recently been discovered and are attracting attention. For example, nanocrystals, which are metal halide nanocrystals composed of cesium, lead, and halogen, and have a perovskite-type crystal structure represented by the general formula _CsPb Non-patent Document 1 discloses that it has the advantage of being able to control the emission wavelength by adjusting the ratio and has excellent physical properties as a light-emitting material. Additionally, particle size control is easier compared to InP quantum dots, etc., which is advantageous in terms of productivity. Patent Document 1 discloses a luminescent crystal having a perovskite-type crystal structure, a composition containing a solid polymer derived from an acrylate polymer, and a luminescent component.

Patent Document 1: International Publication No. 2018/028870

Non-patent Document 1: Nano Letters, 2015, 15, 3692-3696

However, a dispersion containing nanocrystals with a perovskite-type crystal structure is required to have little change in luminescence characteristics and excellent long-term storage properties.

The purpose of the present invention is to provide a dispersion containing luminescent particles containing nanocrystals, which has little change in luminescence properties and has excellent long-term storage.

Another object of the present invention is to provide a composition containing such a dispersion, and a light conversion layer formed from the composition.

The present invention has the following aspects.

[1] A dispersion containing luminescent particles having a surface layer containing a structure having siloxane bonds on the surface of a semiconductor nanocrystal made of metal halide, and having a moisture content of 0.10% or more and 1.0% or less.

[2] The dispersion according to [1], wherein the ratio of water to the luminescent particles (water/luminescent particles) is 0.05 or more and 10.0 or less.

[3] The semiconductor nanocrystal is a compound represented by the general formula A _{a M b}

Wherein A is Cs, Rb, methylammonium, formamidinium, ammonium, 2-phenylethylammonium, pyrrolidinium, piperidinium, 1-butyl-1-methylpiperidinium, tetramethylammonium, tetraethylammonium, Represents one or more cations selected from the group consisting of benzyltrimethylammonium and benzyltriethylammonium,

Wherein M represents a metal ion selected from the group consisting of Pb, Sn, Ge, Bi, Sb, Ag, In, Cu, Yb, Ti, Pd, Mn, Eu, Zr and Tb,

wherein X represents one or more halide ions selected from the group consisting of F, Cl, Br and I,

The dispersion according to [1] or [2], wherein a represents a positive number from 1 to 7, b represents a positive number from 1 to 4, and c represents a positive number from 1 to 16.

[4] The dispersion according to any one of [1] to [3], wherein the semiconductor nanocrystals have a perovskite-type crystal structure.

[5] A composition comprising the dispersion according to any one of [1] to [4] and a thermoplastic resin.

[6] The composition according to [5], wherein the thermoplastic resin is at least one selected from acrylic resin, styrene resin, cyclic olefin resin, cellulose acylate resin, and polycarbonate resin.

[7] A light conversion layer formed from the composition according to [5] or [6].

According to the present invention, it is possible to provide a dispersion containing luminescent particles containing nanocrystals with little change in luminescence characteristics and excellent long-term storage, a composition containing the dispersion, and a light conversion layer formed from the composition. there is.

1 is a cross-sectional view schematically showing one embodiment of a laminated structure including a light conversion layer according to the present invention.
Figure 2 is a cross-sectional view schematically showing one embodiment of a light-emitting device provided with a light conversion layer according to the present invention.
3 is a schematic diagram showing the configuration of an active matrix circuit.
FIG. 4 is a schematic diagram showing the configuration of the active matrix circuit shown in FIG. 3.

The dispersion of the present invention is a luminescent particle (hereinafter referred to as “luminescent particle”) having a surface layer containing a structure having a siloxane bond on the surface of a semiconductor nanocrystal made of a metal halide (hereinafter simply referred to as “nanocrystal”). 」), and the moisture content is 0.10% or more and 1.0% or less. As will be described later, the dispersion of the present invention can be suitably used as a wavelength conversion material for forming a light conversion layer used in, for example, display elements such as light emitting diodes (LEDs).

The dispersion of the present invention contains luminescent particles containing luminescent semiconductor nanocrystals that can emit light (fluorescence or phosphorescence) of a different wavelength than the absorbed wavelength by absorbing light of a predetermined wavelength. Here, luminescence is preferably the property of emitting light by excitation of electrons. When excitation light is irradiated, electrons contained in the nanocrystal are excited from the ground state to the excited state, and light emission occurs when the electrons return to the ground state. It is more preferable that it is a property.

1. Luminescent particles

<Semiconductor nanocrystals made of metal halide>

In the present invention, the nanocrystal is a semiconductor nanocrystal made of metal halide, and is a nano-sized crystal (nanocrystal particle) that absorbs excitation light and emits fluorescence or phosphorescence. These nanocrystals are crystals with a maximum particle diameter of 100 nm or less, as measured by, for example, a transmission electron microscope or a scanning electron microscope. Nanocrystals can be excited by, for example, light energy or electrical energy of a predetermined wavelength and emit fluorescence or phosphorescence. Additionally, nanocrystals that are quantum dots made of metal halide can produce light emission with a narrower half width.

Nanocrystals are compounds represented _by the general formula: A _a M _b Here, a is a positive number from 1 to 7, b is a positive number from 1 to 4, and c is a positive number from 1 to 16.

_{General formula : Specific examples of compounds represented by A a M b ​ , A 3 MX 5 , A 3 M 2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Compounds represented by 9 , A 3 M 3 ​}

In the above formula, A represents a monovalent cation and is at least one of an organic cation and a metal cation. Organic cations include ammonium, methylammonium, formamidinium, guanidinium, imidazolium, pyridinium, pyrrolidinium, and protonated thiourea, and metal cations include Cs, Rb, and K. Cations such as , Na, and Li can be mentioned.

M represents at least one type of metal cation. Specifically, one type of metal cation (M ¹ ), two types of metal cations (M ¹ _α M ² _β ), three types of metal cations (M ¹ _α M ² _β M ³ _γ ), and four types of metal cations. (M ¹ _α M ² _β M ³ _γ M ⁴ _δ ) and the like. However, α, β, γ, and δ each represent real numbers from 0 to 1, and also represent α+β+γ+δ=1. The metal cations represented by M include groups 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, and 15. and selected metal cations. More preferably, Ag, 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, and Zr.

X represents an anion containing at least one type of halogen, and specifically contains one or two or more types of halide anions. When two or more types of anions coexist as Such anions include halide ions such as F ^- , Cl ^- , Br ^- , and I ^- .

Nanocrystals can control their emission wavelength (emission color) by adjusting their particle size and the type and abundance ratio of anions constituting the X site. Additionally, the nanocrystal may be one to which metal ions such as Bi, Mn, Ca, Eu, Sb, or Yb have been added (doped) from the viewpoint of further improving the luminescence characteristics.

Among the nanocrystals represented _by the general formula: A _a M _b It is particularly desirable as a nanocrystal because the emission wavelength (emission color) can be controlled by adjusting the type and abundance ratio of the anions constituting the site.

Specifically, from the viewpoint of having excellent luminescence properties, compounds represented by AMX ₃ , A ₃ MX ₅ , A ₃ MX ₆ , A ₄ MX ₆ , and A ₂ MX ₆ are preferred, and are preferred due to their luminescence properties and ease of synthesis. From this point of view, AMX ₃ is more preferable. A, M and X in the formula are as above. In addition, the compound having a perovskite-type crystal structure may be one to which metal ions such as Bi, Mn, Ca, Eu, Sb, and Yb have been added (doped), as described above.

Among compounds exhibiting a perovskite-type crystal structure, from the viewpoint of ease of synthesis, good luminescent properties, and fastness of the crystal structure, A is selected from the group consisting of Cs, Rb, K, Na, Li, methylammonium, and formamidinium. It is preferably a cation selected, more preferably a cation selected from Cs, Rb, methylammonium and formamidinium, and even more preferably a cation selected from Cs and formamidinium.

M is one type of metal cation (M ¹ ), or two types of metal cations (M ¹ _α M ² _β (however, α and β each represent real numbers from 0 to 1, and α + β = 1). ), and in terms of ease of synthesis, good luminescence properties and fastness of the crystal structure, it is composed of Pb, Sn, Ge, Bi, Sb, Ag, In, Cu, Yb, Ti, Pd, Mn, Eu, Zr and Tb. A metal ion is preferably selected from the group consisting of Pb, Sn, Bi, Sb, Ag, In, Cu, Mn and Zr, and more preferably a metal ion selected from the group consisting of Pb, Sn and Cu. The metal ion selected is more preferred, and Pb ions are particularly preferred.

^{It is preferable that ​ ​} A halide ion selected from the group consisting of ^- is more preferable, a halide ion selected from the group consisting of Br ^- and I ^- is more preferable, and Br ^- is particularly preferable.

As a specific composition of nanocrystals having a perovskite-type crystal structure, CsPbBr ₃ , (CH ₃ NH ₃ )PbBr ₃ , (CHN ₂ H ₄ )PbBr ₃ , CsPbI ₃ , (CH ₃ NH ₃ )PbI ₃ , (CHN ₂ H ₄ )PbI ₃ , CsPb(Br/I) ₃ , (CH ₃ NH ₃ )Pb(Br/I) ₃ , (CHN ₂ H ₄ )Pb(Br/I) ₃ , etc., using Pb as M Nanocrystals are preferable because they have excellent light intensity and quantum efficiency. In addition, in addition to Pb as M, 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 , etc. Nanocrystals using metal cations are desirable because they are low-toxic and have little impact on the environment.

The nanocrystals include a red luminescent crystal that emits light (red light) having an emission peak in the wavelength range of 605 to 665 nm, a green luminescent crystal that emits light (green light) that has an emission peak in the wavelength range of 500 to 560 nm, A blue luminescent crystal, etc. that emits light (blue) with an emission peak in the wavelength range of 420 to 480 nm can be selected and used.

Meanwhile, the wavelength of the emission peak of the nanocrystal can be confirmed, for example, in a fluorescence spectrum or phosphorescence spectrum measured using an absolute PL quantum yield measuring device.

Red luminescent nanocrystals are 665 nm or less, 663 nm or less, 660 nm or less, 658 nm or less, 655 nm or less, 653 nm or less, 651 nm or less, 650 nm or less, 647 nm or less, 645 nm or less, 643 nm or less. , preferably having an emission peak in a wavelength range of 640 nm or less, 637 nm or less, 635 nm or less, 632 nm or less, or 630 nm or less, and 628 nm or more, 625 nm or more, 623 nm or more, 620 nm or more, 615 nm. It is preferable to have an emission peak in a wavelength range of 610 nm or more, 607 nm or more, or 605 nm or more.

These upper and lower limits can be arbitrarily combined. Meanwhile, even in the same description below, the individually described upper and lower limits can be arbitrarily combined.

Green luminescent nanocrystals are 560 nm or less, 557 nm or less, 555 nm or less, 550 nm or less, 547 nm or less, 545 nm or less, 543 nm or less, 540 nm or less, 537 nm or less, 535 nm or less, 532 nm or less. Alternatively, it is preferable to have an emission peak in a wavelength range of 530 nm or less, 528 nm or more, 525 nm or more, 523 nm or more, 520 nm or more, 515 nm or more, 510 nm or more, 507 nm or more, 505 nm or more, 503 nm. It is desirable to have an emission peak in a wavelength range of 500 nm or more.

Blue luminescent nanocrystals are 480 nm or less, 477 nm or less, 475 nm or less, 470 nm or less, 467 nm or less, 465 nm or less, 463 nm or less, 460 nm or less, 457 nm or less, 455 nm or less, 452 nm or less. or preferably has an emission peak in a wavelength range of 450 nm or less, 450 nm or more, 445 nm or more, 440 nm or more, 435 nm or more, 430 nm or more, 428 nm or more, 425 nm or more, 422 nm or more, or 420 nm. It is desirable to have an emission peak in the above wavelength range.

The shape of the nanocrystal is not particularly limited, and may be any geometric shape or any irregular shape. The shape of the nanocrystal includes, for example, a rectangular parallelepiped, a cubic shape, a sphere, a tetrahedron, an ellipsoid, a pyramid shape, a disk shape, a branch shape, a net shape, a rod shape, etc. The shape of the nanocrystal is preferably rectangular, cubic, or spherical.

The average particle diameter (volume average diameter) of the nanocrystals is preferably 40 nm or less, more preferably 30 nm or less, further preferably 20 nm or less, and especially preferably 15 nm or less. Additionally, the average particle diameter of the nanocrystals is preferably 1 nm or more, more preferably 1.5 nm or more, still more preferably 2 nm or more, and especially preferably 3 nm or more. Nanocrystals with such an average particle diameter can not only obtain the desired emission wavelength, but can also suppress the formation of secondary particles due to agglomeration of nanocrystals and suppress the decline in fluorescence quantum yield, luminance, and color reproducibility. there is.

Meanwhile, the average particle diameter of nanocrystals is determined by measuring the particle size of the nanocrystals using a transmission electron microscope (TEM), scanning electron microscope (SEM), or X-ray diffraction (XRD), and calculating the average particle size based on volume. obtained.

<Surface layer containing a structure with siloxane bonds>

The luminescent particles constituting the dispersion of the present invention have a surface layer containing a structure having siloxane bonds on the surface of the nanocrystals. In other words, the luminescent particle has a nanocrystal as its core, and has a surface layer containing siloxane bonds as a shell on at least part of its surface.

The surface layer containing such a structure having siloxane bonds may be composed of a single layer or may be composed of multiple layers.

By providing a surface layer containing a structure in which nanocrystals have siloxane bonds, the stability of the luminescent particles to moisture and oxygen, light resistance, etc. can be improved. Additionally, it is preferable from the viewpoint of improving the long-term storage of the dispersion of the present invention and the durability of the optical properties of the light conversion layer formed from a composition containing the present dispersion.

The surface layer containing a structure having siloxane bonds is preferably composed of a ligand containing a compound capable of coordinating with the surface of the nanocrystal and forming siloxane bonds between molecules.

These ligands include silane compounds (hereinafter also referred to as “silane compounds”) that have a bonding group that binds to a cation or anion contained in the nanocrystal and a reactive group capable of forming a siloxane bond (hereinafter also referred to as “silane compound”), but are included in the nanocrystal. It may further include a compound having a binding group that binds to a cation or anion.

In the silane compound, the reactive group capable of forming a siloxane bond is preferably a hydrolyzable silyl group such as a silanol group or an alkoxysilyl group having 1 to 6 carbon atoms, from the viewpoint of being able to easily form a siloxane bond, and a silanol group. , an alkoxysilyl group having 1 to 2 carbon atoms is more preferable. In other words, a silane compound is a silane compound that has a bonding group that can be bonded to the surface of a nanocrystal and a hydrolyzable silyl group.

Examples of the bonding group that the silane compound has include the bonding groups described above, and among them, at least one of a carboxyl group, a mercapto group, and an amino group is preferable. Since these bonding groups have a higher affinity for cations or anions contained in nanocrystals than hydrolyzable silyl groups, the silane compound coordinates the bonding groups toward the nanocrystal side. Additionally, by forming a siloxane bond through condensation of the hydrolyzable silyl group of the silane compound, a surface layer containing a structure having a siloxane bond can be formed more easily and reliably.

As the silane compound, a carboxyl group-containing silane compound, an amino group-containing silane compound, and a mercapto group-containing silane compound are preferable. These may be used individually or in combination of two or more types.

Silane compounds containing a carboxyl group include, for example, 3-(trimethoxysilyl)propionic acid, 3-(triethoxysilyl)propionic acid, 2-carboxyethylphenylbis(2-methoxyethoxy)silane, N-[3-( trimethoxysilyl)propyl]-N'-carboxymethylethylenediamine, N-[3-(trimethoxysilyl)propyl]phthalamide, N-[3-(trimethoxysilyl)propyl]ethylenediamine-N, N',N'-triacetic acid, (6-triethoxysilyl)-3-[[[3-(triethoxysilyl)propyl]amino]carbonyl]hexanoic acid, etc. can be mentioned.

Silane compounds containing amino groups include, for example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, and N-(2- Aminoethyl)-3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldipropoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiisopropoxy Silane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-amino Propyltripropoxysilane, N-(2-aminoethyl)-3-aminopropyltriisopropoxysilane, N-(2-aminoethyl)-3-aminoisobutyldimethylmethoxysilane, N-(2-amino Ethyl)-3-aminoisobutylmethyldimethoxysilane, N-(2-aminoethyl)-11-aminundecyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylsilanetriol, 3 -Triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N,N-bis[3-(trimethoxysilyl)propyl ]Ethylenediamine, (aminoethylaminoethyl)phenyltrimethoxysilane, (aminoethylaminoethyl)phenyltriethoxysilane, (aminoethylaminoethyl)phenyltripropoxysilane, (aminoethylaminoethyl)phenyltriisoprop Poxysilane, (aminoethylaminomethyl)phenyltrimethoxysilane, (aminoethylaminomethyl)phenyltriethoxysilane, (aminoethylaminomethyl)phenyltripropoxysilane, (aminoethylaminomethyl)phenyltriisopropoxy Silane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropylmethyldimethoxysilane, N-β-(N -Vinylbenzylaminoethyl)-N-γ-(N-vinylbenzyl)-γ-aminopropyltrimethoxysilane, N-β-(N-di(vinylbenzyl)aminoethyl)-γ-aminopropyltrimethoxy Silane, N-β-(N-di(vinylbenzyl)aminoethyl)-N-γ-(N-vinylbenzyl)-γ-aminopropyltrimethoxysilane, methylbenzylaminoethylaminopropyltrimethoxysilane, dimethyl Benzylaminoethylaminopropyltrimethoxysilane, Benzylaminoethylaminopropyltrimethoxysilane, Benzylaminoethylaminopropyltriethoxysilane, 3-ureidopropyltriethoxysilane, 3-(N-phenyl)aminopropyltri Methoxysilane, N,N-bis[3-(trimethoxysilyl)propyl]ethylenediamine, (aminoethylaminoethyl)phenethyltrimethoxysilane, (aminoethylaminoethyl)phenethyltriethoxysilane, (aminoethyl Aminoethyl)phenethyltripropoxysilane, (Aminoethylaminoethyl)phenethyltriisopropoxysilane, (Aminoethylaminomethyl)phenethyltrimethoxysilane, (Aminoethylaminomethyl)phenethyltriethoxysilane, (Aminoethylaminomethyl)phenethyltriethoxysilane Ethylaminomethyl)phenethyltripropoxysilane, (aminoethylaminomethyl)phenethyltriisopropoxysilane, N-[2-[3-(trimethoxysilyl)propylamino]ethyl]ethylenediamine, N-[ 2-[3-(triethoxysilyl)propylamino]ethyl]ethylenediamine, N-[2-[3-(tripropoxysilyl)propylamino]ethyl]ethylenediamine, N-[2-[3-( and triisopropoxysilyl)propylamino]ethyl]ethylenediamine.

Silane compounds containing a mercapto group include, for example, 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, etc. can be mentioned.

Binding groups that bind to cations or anions contained in nanocrystals include, for example, carboxyl group, carboxylic acid anhydride group, amino group, ammonium group, mercapto group, phosphine group, phosphine oxide group, phosphoric acid group, phosphonic acid group, phosphinic acid group, At least one type of sulfonic acid group, boronic acid group, and salts thereof can be mentioned. Among them, at least one type of carboxyl group, amino group, mercapto group, sulfonic acid group, phosphonic acid group, and salts thereof is preferable.

A ligand other than a silane compound, which is a compound having a binding group that binds to a cation or anion contained in a nanocrystal, and specifically, a carboxyl group-containing compound, an amino group-containing compound, a mercapto group-containing compound, a sulfonic acid group-containing compound, and a phosphonic acid group-containing compound. Compounds and their salts are preferred. These may be used individually, or two or more types may be used together.

From the viewpoint of improving the stability of the luminescent particles, it is better to use one or more types of carboxyl group-containing compounds, amino group-containing compounds, sulfonic acid group-containing compounds, phosphonic acid group-containing compounds, and salts thereof, and one or more types of silane compounds other than silane compounds. desirable.

The ligand may be coexisted during the synthesis of the nanocrystal, or after forming the nanocrystal, it may be replaced with a different ligand from the ligand coexisted during the synthesis of the nanocrystal.

Carboxyl group-containing compounds include, for example, 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, γ-linolenic acid, 3-nonenic acid, 2-nonenic acid, trans-2-octenoic acid , petrolseric 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, decanoic acid, arachidic acid, heneicosanoic acid, heptadecanoic acid, heptanoic acid, hexanoic acid, heptacosanoic acid, lauric acid, Listic acid, melisic acid, octacosanoic acid, nonadecanoic acid, nonacosanoic acid, n-octanoic acid, palmitic acid, pentadecanoic acid, propionic acid, pentacosanoic acid, nonanoic acid, stearic acid, lignoceric acid, trichosanoic acid. , tridecanoic acid, undecanoic acid, valeric acid, etc., and straight-chain or branched aliphatic carboxylic acids having 1 to 30 carbon atoms.

Amino group-containing compounds include, for example, 1-aminoheptadecane, 1-aminononadecane, heptadecan-9-amine, stearylamine, oleylamine, 2-n-octyl-1-dodecylamine, allylamine, and amyl. Amine, 2-ethoxyethylamine, 3-ethoxypropylamine, isobutylamine, isoamylamine, 3-methoxypropylamine, 2-methoxyethylamine, 2-methylbutylamine, neopentylamine, propylamine , methylamine, ethylamine, butylamine, hexylamine, heptylamine, octylamine, 1-aminodecane, nonylamine, 1-aminoundecane, dodecylamine, 1-aminopentadecane, 1-aminotridecane, hexamethylamine Examples include linear or branched aliphatic amines having 1 to 30 carbon atoms, such as decylamine and tetradecylamine.

Examples of mercapto group-containing compounds include n-dodecylthiol, tert-dodecylthiol, 1-dodecanethiol, n-octanethiol, and 1-octadecanethiol.

Sulfonic acid group-containing compounds or salts thereof include, for example, dodecylbenzenesulfonic acid, dodecylphosphonic acid, sodium 4-n-octylbenzenesulfonate, sodium 4-dodecylbenzene-1-sulfonate, sodium 4-undecylbenzenesulfonate, 4 -Sodium tetradecylbenzene-1-sulfonate, sodium 4-tridecylbenzene-1-sulfonate, sodium 1-decanesulfonate, sodium 1-dodecanesulfonate, sodium lauryl sulfate, etc.

Examples of the phosphonic acid group-containing compound or its salt include dodecylphosphonic acid.

Among the above compounds, in the present invention, as the ligand used in combination with the silane compound, oleic acid, octanoic acid, lauric acid, dodecylbenzenesulfonic acid, dodecylphosphonic acid, oleylamine, octylamine, and trioctylphosphine are preferred. , oleic acid, lauric acid, oleylamine, dodecylbenzenesulfonic acid, and dodecylphosphonic acid are more preferred.

In particular, the surface layer containing a structure having a siloxane bond coordinates, for example, oleic acid or 3-aminopropyltriethoxysilane as a ligand to the surface of the nanocrystal, and further coordinates an alkoxysilyl group possessed by 3-aminopropyltriethoxysilane. Those obtained by condensation to form siloxane bonds are preferred.

Additionally, the ligand used in combination with the silane compound may be added to the nanocrystal surface after forming a shell layer containing a siloxane bond on the nanocrystal surface to coordinate the nanocrystal surface.

The thickness of the surface layer containing the structure having siloxane bonds is preferably in the range of 0.5 to 50 nm, and more preferably in the range of 1.0 to 30 nm. If the thickness of the surface layer including the structure having siloxane bonds is within the above range, the thermal stability of the luminescent particles can be sufficiently increased. On the other hand, the thickness of the surface layer containing the structure having siloxane bonds can be changed by adjusting the number of atoms (chain length) of the linking structure connecting the linking group of the ligand and the reactive group.

In the luminescent particles, in addition to the above ligands, didodecyldimethylammonium bromide, phenethylammonium bromide, phenethylammonium iodide, methyltrioctylammonium bromide, tetraoctylammonium bromide, didecyldimethylammonium bromide, and ditetradecyldimethylammonium bromide. Ammonium salts such as may be coordinated to the surface of the nanocrystal.

<Method for producing luminescent particles and dispersions>

Luminescent particles can be produced, for example, by the following method.

That is, forming nanocrystals from a solution containing a raw material compound capable of synthesizing nanocrystals, a silane compound having a binding group capable of bonding to the surface of the nanocrystal and a hydrolyzable silyl group, and a solvent, while forming nanocrystals, siloxane is added to the surface of the nanocrystals. By forming the bond, luminescent particles are obtained with a surface layer containing a structure having a siloxane bond on the surface of the nanocrystal.

For this manufacturing method, for example, a hot injection method or a LARP method can be applied.

The manufacturing method for obtaining luminescent particles includes a raw material compound capable of synthesizing nanocrystals composed of the compound represented by A _{a M b} ), a silane compound, and a solvent are prepared, mixed, and then condensed with the reactive group (hydrolyzable silyl group) of the silane compound coordinated to the surface of the precipitated nanocrystals.

When mixing the solution, it may be heated or may not be heated.

Here, the raw material compounds are a compound containing a cation A, a compound containing a metal ion M, and a compound containing a halide ion X. Compounds containing cation A include, for example, hydroxide, acetate, carbonate, nitrate, and sulfate of cation A; their hydrates; etc. can be mentioned. Compounds containing metal ions M include oxides, hydroxides, halide salts, acetates, carbonates, nitrates, and sulfates of metal ions; their hydrates; etc. can be mentioned. Compounds containing the halide ion

On the other hand, as the first raw material compound, a metal halide salt containing a metal ion M and also containing a halide X can be suitably used.

Examples of solvents include 1-octadecene, dioctyl ether, and diphenyl ether.

In the case of heating when mixing a solution, specifically, a first solution containing a compound containing a cation A and a solvent, and a compound containing a metal ion M and a compound containing a halide ion Prepare the second solution, respectively. In the second solution, the above-described metal halide salt may be used instead of the compound containing the metal ion M and the compound containing the halide ion X.

At this time, each solution is prepared by adding the above-mentioned ligand to one solution and adding a silane compound to the other solution. The solution containing the silane compound may contain the above-mentioned ligand. By allowing the ligand or silane compound to coexist in the preparation of each solution, when the first solution and the second solution are reacted, nanocrystals with the ligand or silane compound on the surface can be obtained. Additionally, by coexisting a ligand or a silane compound, excessive crystal growth can be prevented and nanocrystals within the desired particle size range can be obtained.

The amount of the ligand and the silane compound is in the range of 10% to 100% of the volume of the solvent used in the preparation of each solution, from the viewpoint that it is easy to obtain nanocrystals with a ligand coordinated to the surface of the nanocrystal. This is desirable from the viewpoint of achieving the effect of preventing excessive crystal growth by allowing the ligands to coexist.

Next, a predetermined amount of the first solution is added to a predetermined amount of the second solution heated to 140 to 260°C, reacted, cooled to -20 to 30°C, and further stirred at 10 to 30°C in the air to form nano Luminescent particles having a surface layer containing siloxane bonds are deposited on the surface of the crystal.

The reaction time after mixing the first solution with the second solution is preferably within 5 minutes, and is preferably within 1 second to 60 seconds in order to suppress excessive crystal growth and obtain nanocrystals with a particle diameter capable of emitting light. It is preferable, and the range of 3 seconds to 10 seconds is more preferable. In addition, the cooling time after the reaction may vary depending on the set temperature when mixing the first solution with the second solution or the scale of the reaction, but from the viewpoint of rapidly precipitating nanocrystals, it is usually in the range of 1 to 60 minutes. It is desirable to be Meanwhile, there is no particular limitation on the cooling means, and depending on the target cooling temperature and cooling time, ice water, water-ethylene glycol mixed refrigerant, dry ice-acetone bath, etc. can be appropriately selected and used. In addition, the preparation of each of the above solutions, mixing the solutions to react, and then cooling the solutions may be performed under an air atmosphere or an inert gas atmosphere such as nitrogen or argon.

On the other hand, the mixing amount of the first solution and the second solution is the compound containing the cation A, the compound containing the metal ion M, and the compound containing the halide ion It can be appropriately adjusted depending on the respective contents of the metal halide salt containing the halide

For example, with respect to 40 mL of solvent, 0.2 to 2 g of cesium carbonate as a compound containing cation A and 0.1 to 10 mL of oleic acid as a ligand are mixed, and dried under reduced pressure at 90 to 150°C for 10 to 180 minutes. It can be dissolved by heating to 100-200°C to prepare a first solution, which is a cesium-oleic acid solution.

Meanwhile, 20 to 100 mg of lead(II) bromide as a metal halide containing metal ion M and halide ion A second solution can be prepared by adding 0.1 to 2 mL of 3-aminopropyltriethoxysilane as a compound.

Next, the first solution is added to the second solution heated to 140 to 260°C and reacted, then cooled to -20 to 30°C and stirred, and 3-aminopropyltriethoxysilane and oleic acid are coordinated on the surface. Nanocrystals precipitate.

This mixture was stirred for an additional 5 to 300 minutes at 10 to 30°C in an atmosphere with a humidity of 5 to 60%, and then methyl acetate was added to form nanocrystals, forming 3-aminopropyltriethoxy on the surface of the nanocrystals. The ethoxysilyl group of silane condenses to form a siloxane bond, and a suspension containing luminescent particles having a surface layer containing a structure having a siloxane bond on the surface of the nanocrystal is obtained.

The luminescent particles can be recovered by, for example, centrifuging the obtained suspension. A dispersion medium is added to the recovered luminescent particles and dispersed by shaking and stirring to obtain a dispersion of luminescent particles. Then, if necessary, water is added to the dispersion or dehydration treatment is performed to adjust the water content in the dispersion of the luminescent particles to a range of 0.10% or more and 1.0% or less.

Dispersion media include, for example, cyclohexane, hexane, heptane, chloroform, toluene, octane, chlorobenzene, tetralin, diphenyl ether, propylene glycol monomethyl ether acetate, butylcarbitol acetate, or mixtures thereof. . From the viewpoint of easy removal of the solvent from the composition when forming the light conversion layer, the boiling point of the solvent is preferably 300°C or lower, more preferably 200°C or lower, and even more preferably 150°C or lower.

The amount of dispersion medium in the dispersion is preferably 80 to 99.5% by mass based on the entire dispersion.

This dispersion is a colloidal solution in which luminescent particles containing nanocrystals are dispersed in a solvent. It is desirable to remove impurities from this dispersion by filtration, centrifugation, adsorption, column chromatography, etc. Additionally, when the dispersion is not used immediately, it is preferable to store it under light blocking from the viewpoint of maintaining stability of optical properties and dispersion stability. The storage temperature is preferably -70°C or higher and 40°C or lower, more preferably -50°C or higher and 30°C or lower, more preferably -30°C or higher and 20°C or lower, and especially preferably -20°C or higher and 10°C or lower.

As described above, when obtaining nanocrystals, the first solution and the second solution may be mixed in a heated state, or may be mixed without heating. In that case, a method of precipitating nanocrystals is given by dropping and mixing a solution containing a raw material compound of nanocrystals and a ligand different from the silane compound into a solution in which a silane compound is dissolved in a poor solvent for nanocrystals under air, thereby precipitating nanocrystals. there is.

For example, for 10 mL of a solvent (good solvent) that dissolves nanocrystals such as dimethyl sulfoxide, N,N-dimethylformamide, or N-methylformamide, 5 to 25 mg of cesium bromide as a compound containing cation A is used. , dissolve by mixing 10 to 50 mg of lead (II) bromide as a metal halide containing metal ion M and halide ion Prepare solution (i). Meanwhile, prepare solution (ii) by adding 0.01 to 0.5 mL of 3-aminopropyltriethoxysilane as a silane compound to 5 mL of a poor solvent for nanocrystals, such as isopropanol, toluene, hexane, or cyclohexane.

Then, 0.1 to 1 mL of solution (i) is added to 5 mL of solution (ii) at 0 to 30°C in air and stirred for 5 to 180 seconds. When solution (i) is added to solution (ii), nanocrystals precipitate, and 3-aminopropyltriethoxysilane, oleic acid, and oleylamine coordinate on the surface of these nanocrystals. Then, during stirring in the atmosphere, the alkoxysilyl groups of 3-aminopropyltriethoxysilane condense to obtain a suspension containing luminescent particles having a surface layer containing siloxane bonds on the surface of the nanocrystals.

The luminescent particles can be recovered by, for example, centrifuging the obtained suspension. A dispersion medium such as toluene is added to the recovered luminescent particles and dispersed by shaking and stirring to obtain a dispersion of luminescent particles. Then, if necessary, water is added to the dispersion or dehydration treatment is performed to adjust the water content in the dispersion of the luminescent particles to a range of 0.10% or more and 1.0% or less.

The average particle diameter (volume average diameter) of the luminescent particles is preferably 200 nm or less, more preferably 150 nm or less, further preferably 100 nm or less, and especially preferably 50 nm or less. Additionally, the average particle diameter of the luminescent particles is preferably 1 nm or more, more preferably 1.5 nm or more, still more preferably 2 nm or more, and particularly preferably 5 nm or more. If the average particle diameter is within the above range, it is easy to emit light of a desired wavelength. On the other hand, the average particle diameter (volume average diameter) of the luminescent particles is obtained by measuring the particle diameter of each particle with a transmission electron microscope or scanning electron microscope and calculating the volume average diameter.

Luminescent particles can be produced using a batch reactor. In addition, from the viewpoints of reducing unevenness in particle size, preventing contamination of impurities, manufacturing efficiency, and temperature control, it is more preferable to manufacture using a flow reactor such as continuous laminar flow, droplet base, or forced thin film type.

2. Moisture content of dispersion

The water content of the dispersion of the present invention is 0.10% or more and 1.0% or less, and more preferably 0.50% or more and 0.90% or less, in order to obtain a passivation effect by water on the nanocrystal surface.

Additionally, in the dispersion of the present invention, the ratio of water to the luminescent particles (water/luminescent particles) is preferably 0.05 or more and 10.0 or less in mass ratio, and more preferably 1.0 or more and 7.5 or less.

On the other hand, the water content of the dispersion of the present invention can be measured by a Karl Fischer moisture meter (for example, model number CA-06, manufactured by Mitsubishi Chemical Corporation, and the vaporization unit is VA-06, manufactured by the company).

As a means of controlling the moisture content of the dispersion of the present invention and the ratio (mass ratio) of water to the luminescent particles within the above range, the following can be mentioned.

For example, from the viewpoint of promoting the formation of siloxane bonds by condensation of the hydrolyzable silyl group of the above-mentioned silane compound, water may be added when forming the luminescent particles, or water may be added and contained in the solvent or reaction atmosphere without adding water. The formation of siloxane bonds may be promoted by a trace amount of moisture. In this case, the luminescent particles may be prepared in an atmospheric atmosphere using a raw material compound that has not been specifically subjected to dehydration treatment or the like in advance. Additionally, the formation of siloxane bonds may be promoted by heating. The temperature when heating is preferably 20°C or higher and 120°C or lower, more preferably 30°C or higher and 100°C or lower, and even more preferably 40°C or higher and 80°C or lower.

In addition, after forming the dispersion containing the luminescent particles, water may be added to the dispersion for the purpose of adjusting the water content within the above predetermined range, or dehydration treatment by heating or reduced pressure may be performed as necessary.

Additionally, after dehydration treatment by heating or reduced pressure, the moisture content of the dispersion may be adjusted by adding water.

When a ligand is coexisted when forming a nanocrystal, this ligand coordinates the cation or anion (dangling bond) present on the surface of the nanocrystal, thereby stabilizing the nanocrystal. Additionally, when water is present during the formation of nanocrystals, it is thought that the water itself may reduce the capping ligand density on the nanocrystal surface and function as a so-called ligand, temporarily contributing to the passivation of the nanocrystal surface. On the other hand, if a large amount of water is present, the ligand or water coordinated to the nanocrystal is not immobilized on the surface of the nanocrystal, so it gradually leaves, and the nanocrystal components elute or aggregate, causing a decrease in luminescence properties.

In the dispersion of the present invention, as described above, a ligand comprising a compound capable of coordinating to the surface of the nanocrystal and forming a siloxane bond between molecules, suitably a bond that binds to a cation or anion contained in the nanocrystal Both the compound having a sexual group and the above-mentioned silane compound are used as ligands when forming nanocrystals. The presence of a predetermined amount of water causes condensation of the silane compound, resulting in luminescent particles having a surface layer containing a structure having siloxane bonds on the surface of the nanocrystal. It is thought that it is difficult for ligands to escape from nanocrystals with such a surface layer formed, and it is also difficult for water molecules on the nanocrystal surface to escape. In addition, it is believed that the presence of a surface layer can suppress changes in crystal composition due to movement of ionic components in the nanocrystals and aggregation of luminescent particles, and can sufficiently exhibit luminescent properties.

Therefore, it is assumed that the dispersion of the present invention has improved storage stability and can maintain the luminescent properties of the luminescent particles over a long period of time.

3. Composition

The present invention is also a composition containing the above-described dispersion and a thermoplastic resin.

The thermoplastic resin contained in the composition of the present invention functions as a binder for the luminescent particles and has a role in forming a matrix in which the luminescent particles are dispersed in the light conversion layer formed from the composition of the present invention.

From the viewpoint of excellent dimensional stability, processability, and optical properties as a light conversion layer, the thermoplastic resin preferably has a glass transition temperature (Tg) of -30 to 230°C, more preferably 50 to 200°C, and 60 to 60°C. It is particularly preferable that it is -170°C. Meanwhile, the Tg of the thermoplastic resin was measured using a differential scanning calorimeter (DSC) by first raising the temperature to 300°C and holding it for 10 minutes to eliminate the heat history, then lowering the temperature to -30°C at 10°C/min and holding it for 10 minutes. , it can be obtained as the temperature representing the inflection point of the transition region that appears in a step shape in the thermogram when the temperature is raised again at 10°C/min.

The thermal decomposition temperature (Td) of the thermoplastic resin is preferably 300°C or higher, more preferably 260°C or higher, and even more preferably 220°C or higher.

The refractive index of the thermoplastic resin is preferably 1.35 to 1.77, more preferably 1.40 to 1.65, and even more preferably 1.45 to 1.60.

The total light transmittance of the thermoplastic resin that can be measured based on ISO 13468-2 is preferably 70 to 95%, more preferably 80 to 95%, and even more preferably 90 to 95%.

Thermoplastic resins include acrylic resins, styrene-based resins, cyclic olefin-based resins, cellulose acylate-based resins, polycarbonate-based resins, polyester-based resins, polyolefin-based resins such as polyethylene and polypropylene, polyarylate-based resins, and polysulphins. Examples include phonetic resin, polyethersulfone-based resin, maleimide-based resin, polyamide-based resin, fluorine-based resin, phenoxy resin, and polyetherimide-based resin.

It is preferable that these thermoplastic resins are transparent resins, and one type may be used individually, or two or more types may be used together. Among them, at least one selected from acrylic resin, styrene resin, cyclic olefin resin, cellulose acylate resin, and polycarbonate resin is preferable from the viewpoint of having transparency as an optical film.

Acrylic resins include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, n-hexyl (meth)acrylate, (meth)acrylic acid 2-chloroethyl, (meth)acrylic acid 2-hydroxyethyl, (meth)acrylic acid 3-hydroxypropyl, (meth)acrylic acid 2,3,4,5,6-pentahydroxyhexyl, (meth)acrylic acid ) Homopolymers or copolymers of two or more types of 2,3,4,5-tetrahydroxypentyl acrylic acid can be mentioned. Among them, an acrylic resin containing methyl methacrylate as a main component is more preferable from the viewpoint of excellent thermal stability. As the acrylic resin, various acrylic thermoplastic resins that are industrially manufactured and commercially available can be used.

Meanwhile, in this specification, “(meth)acrylic” is a general term for acrylic, methacryl, and both.

From the viewpoint of heat resistance and film strength, polystyrene, styrene-acrylonitrile-based resin, styrene-acrylic resin, styrene-maleic anhydride-based resin, etc. are preferred as the styrene-based resin. In addition, as a styrene-maleic anhydride resin, for example, "Daylark D332" manufactured by Nova Chemical, etc., and as a styrene-acrylic resin, for example, "Delpet 980N" manufactured by Asahi Kasei Chemical, etc. can be used.

Cyclic olefin-based resins include, for example, norbornene-based resins obtained by addition polymerization or ring-opening polymerization of norbornene-based compounds. Cyclic olefin resin obtained by addition polymerization, for example, Japanese Patent No. 3517471, Japanese Patent No. 3559360, Japanese Patent No. 3867178, Japanese Patent No. 3871721, Japanese Patent No. 3907908, Japanese Patent No. 3945598, Japanese Patent No. Resins described in Publication No. 2005-527696, Japanese Patent Application Publication No. 2006-28993, Japanese Patent Application Publication No. 2006-11361, International Publication No. 2006/004376, and International Publication No. 2006/030797 can be mentioned. In addition, cyclic olefin resins obtained by ring-opening polymerization include International Publication No. 98/14499, Japanese Patent No. 3060532, Japanese Patent No. 3220478, Japanese Patent No. 3273046, Japanese Patent No. 3404027, and Japanese Patent No. 3428176. , Japanese Patent No. 3687231, Japanese Patent No. 3873934, and Japanese Patent No. 3912159.

Cellulose acylate resins include, for example, cellulose acylates in which at least part of the three hydroxyl groups in the cellulose units are replaced with acyl groups. The acyl group preferably has 3 to 22 carbon atoms, and may be either an aliphatic acyl group or an aromatic acyl group, but an aliphatic acyl group with 3 to 7 carbon atoms is preferable. Examples of such aliphatic acyl groups include acetyl group, propionyl group, butyryl group, pentanoyl group, and hexanoyl group. Multiple types of these acyl groups may exist in one cellulose unit.

From the viewpoint of ease of production, cellulose acylates having one or two or more types selected from acetyl groups, propionyl groups, and butyryl groups are particularly preferred. Such cellulose acylates are industrially manufactured and commercially available, and examples include “CAP-482” and “CAB-381” (all brand names, manufactured by EASTMAN CHEMICAL).

Polycarbonate-based resins include polycarbonate resins having a bisphenol A skeleton, for example, Japanese Patent Application Laid-Open No. 2006-277914, Japanese Patent Application Laid-Open No. 2006-106386, and Japanese Patent Application Laid-Open No. 2006-284703. The resins described are preferred. These polycarbonate resins are industrially manufactured and commercially available, and examples include "Taflon MD1500" (brand name, manufactured by Idemitsu Kosan Corporation).

The content of the thermoplastic resin in the composition of the present invention is determined from the viewpoint of excellent viscosity stability, discharge properties and applicability when preparing the composition when applied using an inkjet printing method, and when manufacturing the light conversion layer. From the viewpoint of suppressing the decline in surface smoothness, from the viewpoint of improving the uniformity, solvent resistance, and wear resistance of the surface of the pixel portion made of the composition of the present invention in the light conversion layer, and from the viewpoint of improving excellent optical properties (e.g., external quantum efficiency). From the viewpoint of obtaining, it is preferably 3% by mass or more and 15% by mass or less, more preferably 4% by mass or more and 12% by mass or less, and even more preferably 5% by mass or more and 10% by mass or less with respect to the entire composition.

When applying using an inkjet printing method, the viscosity of the composition of the present invention is usually preferably 2 mPa·s or more, and more preferably 5 mPa·s or more, from the viewpoint of discharge stability. The viscosity of the composition is preferably 20 mPa·s or less, and more preferably 15 mPa·s or less. The viscosity of the composition is measured by, for example, an E-type viscometer.

The surface tension of the composition of the present invention is preferably a surface tension suitable for the inkjet method, and is usually preferably in the range of 20 to 40 mN/m, and more preferably 25 to 35 mN/m. By keeping the surface tension within the above range, the occurrence of flight bending can be suppressed. On the other hand, flight bending refers to a deviation of 30 μm or more in the landing position of the composition from the target position when the composition is ejected from the ink discharge hole.

The composition of the present invention may further contain other components such as polymerization inhibitors, antioxidants, dispersants, surfactants, light scattering particles, plasticizers, and ultraviolet absorbers, as long as they do not impair the effects of the present invention. In addition, the composition of the present invention may further contain a polymerizable compound such as a photopolymerizable compound, a polymerization initiator such as a photopolymerization initiator, a chain transfer agent, etc., to the extent that the effect of the present invention is not impaired.

Examples of polymerization inhibitors include quinone-based compounds such as p-methoxyphenol, cresol, tert-butylcatechol, and 3,5-di-tert-butyl-4-hydroxytoluene; Amine compounds such as p-phenylenediamine, 4-aminodiphenylamine, and N,N'-diphenyl-p-phenylenediamine; Thioether-based compounds such as phenothiazine and distearylthiodipropionate; 2,2,6,6-Tetramethylpiperidine-1-oxyl, 2,2,6,6-tetramethylpiperidine, 4-hydroxy-2,2,6,6-tetramethylpiperidine N-oxyl compounds such as -1-oxyl; Nitroso-based compounds such as N-nitrosodiphenylamine, N-nitrosophenylnaphthylamine, and N-nitrosodinaphthylamine can be mentioned.

When a polymerization inhibitor is contained, the amount is preferably in the range of 0.01 to 1% by mass, more preferably 0.02 to 0.5% by mass, based on the total amount of thermoplastic resin contained in the composition.

Antioxidants include phenol-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, etc., such as pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)]. Propionate, thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)]propionate, octadecyl-3-(3,5-di-tert-butyl-4 -Hydroxyphenyl)propionate, 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro [5.5]undecane, 2,4,8,10-tetrakis(1,1-dimethylethyl)-6-[(2-ethylhexyl)oxy]-12H-dibenzo[d,g][1,3 ,2]dioxaphosphosine, bis[3-(dodecylthio)propionic acid]2,2-bis[[3-(dodecylthio)-1-oxopropyloxy]methyl]-1,3-propanediyl, etc. can be mentioned.

From the viewpoint of the composition and the thermal stability of the light conversion layer formed from the composition, phenol-based antioxidants and phosphorus-based antioxidants are preferable, and phenolic antioxidants are more preferable. Additionally, from the viewpoint of long-term thermal stability of the light conversion layer formed from the composition, it is preferable to use a phenol-based antioxidant and a phosphorus-based antioxidant in combination.

When an antioxidant is contained, the amount is preferably in the range of 0.01 to 2% by mass, more preferably 0.02 to 1% by mass, based on the total amount of thermoplastic resin contained in the composition.

Dispersants include, for example, phosphorus atom-containing compounds such as trioctylphosphine, trioctylphosphine oxide, and hexylphosphonic acid; Nitrogen atom-containing compounds such as oleylamine, octylamine, and trioctylamine; Compounds containing sulfur atoms such as 1-decanethiol, octanethiol, and dodecanethiol; and polymer dispersants such as acrylic resin, polyester resin, and polyurethane resin. These include, for example, the "DISPER (registered trademark) BYK" series manufactured by Big Chemistry, the "TEGO (registered trademark) Dispers" series manufactured by Evonik Corporation, the "EFKA (registered trademark)" series manufactured by BASF Corporation, and the "EFKA (registered trademark)" series manufactured by Nippon Lubrizol Corporation. “SOLSPERSE (registered trademark)” series, “Ajisper (registered trademark)” series manufactured by Ajinomoto Fine Techno Co., Ltd., “DISPARLON (registered trademark)” series manufactured by Kusumoto Kasei Co., Ltd., and “Flolene” manufactured by Kyoesha Kagaku Co., Ltd. (registered trademark)” and other commercial products.

When a dispersant is contained, its amount is preferably in the range of 0.05 to 10% by mass, more preferably 0.1 to 5% by mass, based on the total amount of thermoplastic resin contained in the composition.

The surfactant is preferably a compound that can reduce film thickness unevenness when forming a thin film containing luminescent particles. For example, anionic surfactants such as dialkyl sulfosuccinates, alkylnaphthalenesulfonates, 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-based or fluorine-based surfactants. These include, for example, the “Megapack (registered trademark)” series manufactured by DIC, the “Aftergent (registered trademark)” series manufactured by Neos, the “BYK (registered trademark)” series manufactured by BYK, and the “TEGO” manufactured by Evonik. (registered trademark) Rad” series, “DISPARLON (registered trademark) OX” series manufactured by Kusumoto Chemicals, “Polyflow No. 7”, “Flolene AC-300”, and “Florene” manufactured by Kyoesha Chemical Co., Ltd. It can be obtained as a commercial product such as “AC-303”.

When a surfactant is contained, the amount added is preferably in the range of 0.005 to 2% by mass, more preferably 0.01 to 0.5% by mass, based on the total amount of thermoplastic resin contained in the composition.

The light scattering particles are preferably optically inert inorganic fine particles. The light scattering particles can scatter light from the light source unit irradiated onto the light emitting layer (light conversion layer). Materials constituting the light scattering particles include, for example, simple metals such as tungsten, zirconium, titanium, platinum, bismuth, rhodium, palladium, silver, tin, platinum, and gold; 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, metal oxides such as zinc oxide; Metal carbonates such as magnesium carbonate, barium carbonate, bismuth subcarbonate, and calcium carbonate; Metal hydroxides such as aluminum hydroxide; Examples include complex oxides such as barium zirconate, calcium zirconate, calcium titanate, barium titanate, and strontium titanate, and metal salts such as bismuth nitrate.

Among them, from the viewpoint of superior leakage light reduction effect, it is preferable to include at least one selected from the group consisting of titanium oxide, alumina, zirconium oxide, zinc oxide, calcium carbonate, barium sulfate, and silica, and titanium oxide , it is more preferable that it contains at least one member selected from the group consisting of barium sulfate and calcium carbonate, and titanium oxide is particularly preferable.

When light scattering particles are included, for example, when using the composition of the present invention as a forming material for a color filter layer, the amount is in the range of 1 to 10% by mass relative to the entire composition from the viewpoint of suppressing the transmission of blue light of the backlight. It is preferable, the range of 2 to 7.5 mass% is more preferable, and the range of 3 to 5 mass% is particularly preferable. In addition, when using the composition of the present invention as a forming material for a light conversion sheet, from the viewpoint of extraction of blue light from the backlight, it is preferably in the range of 0.1 to 5% by mass, and is preferably in the range of 0.15 to 3% by mass with respect to the entire composition. is more preferable, and the range of 0.2 to 1.5 mass% is more preferable.

Solvents include, for example, cyclohexane, hexane, heptane, chloroform, toluene, octane, chlorobenzene, tetralin, diphenyl ether, propylene glycol monomethyl ether acetate, butylcarbitol acetate, or mixtures thereof. . From the viewpoint of easy removal of the solvent from the composition when forming the pixel portion, the boiling point of the solvent is preferably 300°C or lower, more preferably 200°C or lower, and still more preferably 150°C or lower.

When the composition further contains a solvent in addition to the solvent constituting the dispersion, the amount is preferably 5 to 50% by mass based on the entire composition from the viewpoint of preventing aggregation of the luminescent particles.

There is no particular limitation on the preparation method of the composition of the present invention, and it can be prepared by mixing the above components. For example, it can be prepared by adding a dispersion, a thermoplastic resin, a solvent and other components as needed, and stirring and mixing using a ball mill, sand mill, bead mill, three-roll mill, paint conditioner, attritor, ultrasonic wave, etc.

When light-scattering particles are included, it can be prepared by separately creating a mill base in which light-scattering particles and a polymer dispersant are mixed and dispersed in the above solvent using a bead mill, and then mixed with the dispersion and a thermoplastic resin.

4. Light conversion layer

A composition containing the dispersion of the present invention is applied on a substrate to form a film, and the film is dried to obtain a film, thereby forming a light conversion layer. In this case, the content of the thermoplastic resin in the composition of the present invention is preferably 3% by mass or more and 30% by mass or less with respect to the entire composition from the viewpoint of dispersibility of luminescent particles in the resulting coating film and luminous efficiency, and is 5% by mass. More than 20 mass% or less is more preferable, and 7 mass% or more and 15 mass% or less is more preferable. Furthermore, from the viewpoint of dispersibility and luminous efficiency, the content of luminescent particles is preferably 0.01% by mass or more and 15% by mass or less, more preferably 0.02% by mass or more and 10% by mass or less, and 0.05% by mass or more with respect to the entire composition. 5% by mass or less is more preferable.

In addition, the composition of the present invention is melted, passed between the first and second pressure surfaces constituting the pinching device, continuously pinched, and molded into a film to form the light conversion layer of the present invention. It can also be formed. In this case, the content of the thermoplastic resin in the composition of the present invention is preferably 60% by mass or more and 97% by mass or less, more preferably 70% by mass or more and 96% by mass or less, and 80% by mass or more and 95% by mass. % or less is more preferable. Furthermore, from the viewpoint of dispersibility and luminous efficiency, the content of luminescent particles is preferably 0.01% by mass or more and 15% by mass or less, more preferably 0.05% by mass or more and 10% by mass or less, and 0.1% by mass or more with respect to the entire composition. 5% by mass or less is more preferable.

Among these, it is preferable to apply the composition of the present invention on a substrate to form a film and then dry the film to obtain a film. The light conversion layer made of the coating film of the composition of the present invention is suitable for use as a color filter and wavelength conversion film.

Methods for applying the composition of the present invention on a substrate include spin coating, die coating, extrusion coating, roll coating, wire bar coating, gravure coating, spray coating, dipping, inkjet method, and printing method. You can. At the time of application, if necessary, hydrocarbons, halogenated hydrocarbons, ethers, alcohols, ketones, esters, aprotic polar compounds, etc. may be further added as solvents to the composition. After the composition is applied to the substrate, it is dried naturally, under heat, or under reduced pressure.

The shape of the substrate when applying the composition of the present invention on the substrate may have a curved surface as a constituent part in addition to a flat plate. The material constituting the substrate can be either an organic material or an inorganic material. Organic materials include, for example, polyethylene terephthalate, polycarbonate, polyimide, polyamide, polymethyl methacrylate, polystyrene, polyvinyl chloride, polytetrafluoroethylene, polychlorotrifluoroethylene, polyarylate, and polysulfone. , triacetylcellulose, cellulose, polyetheretherketone, etc., and inorganic materials include, for example, silicon, glass, calcite, etc.

The wavelength conversion film using the composition of the present invention as a forming material may be heat treated to reduce initial characteristic changes and achieve stable characteristic expression. This heat treatment is preferably performed at a temperature range of 50 to 250°C and a treatment time of 30 seconds to 12 hours.

The wavelength conversion film obtained by this method may be peeled from the substrate and used alone, or may be used without peeling. Additionally, the obtained wavelength conversion film may be laminated or may be used by bonding to another substrate.

When a wavelength conversion film using the composition of the present invention as a forming material is used in a laminated structure, this laminated structure may have any layers such as a substrate, a barrier layer, and a light scattering layer, for example. The materials constituting the substrate are as above. Examples of the barrier layer include polyethylene terephthalate, glass, and the like. Examples of the light scattering layer include a layer containing the light scattering particles and a light scattering film.

An example of the configuration of the laminated structure includes, for example, a structure in which a light conversion layer made of the composition of the present invention as a forming material is sandwiched between two substrates. In that case, in order to protect the light conversion layer from moisture and oxygen, the outer peripheral portion between the substrates may be sealed with a sealing material.

Fig. 1 is a cross-sectional view schematically showing the configuration of the laminated structure of the present embodiment. In the laminated structure 40, the wavelength conversion film 44 of this embodiment is sandwiched between the first substrate 41 and the second substrate 42. The wavelength conversion film 44 is formed using the composition of the present invention containing light scattering particles 441 and luminescent particles 442, and the light scattering particles 441 and luminescent particles 442 are contained in the wavelength conversion film. It is uniformly distributed. The wavelength conversion film 44 is sealed by a sealing layer 43 formed of a sealing material.

The laminated structure using the composition of the present invention as a forming material is suitable for use in, for example, a prism sheet, a light guide plate, a laminated structure containing luminescent particles, and a light emitting device having a light source. Light sources include, for example, light-emitting diodes, lasers, and electroluminescent devices.

Additionally, the laminated structure using the composition of the present invention as a forming material is preferably used as a wavelength conversion member for a display. An example of the configuration when used as a wavelength conversion member is, for example, a structure in which a laminated structure in which a wavelength conversion film made of the composition of the present invention as a forming material is sealed between two barrier layers is installed on a light guide plate. . In this case, the blue light from the light emitting diode installed on the side of the light guide plate is converted into green light or red light by passing through the laminated structure, and the blue light, green light, and red light are mixed to obtain white light, so it can be used as a backlight for a display. You can.

5. Light emitting device

Hereinafter, a case where the color filter pixel portion of a light emitting device equipped with a blue organic LED backlight is formed with the composition of the present invention will be described as an example.

FIG. 2 is a cross-sectional view showing one embodiment of a light-emitting device provided with a light conversion layer made of a cured product of the composition of the present invention, and FIGS. 3 and 4 are schematic diagrams each showing the configuration of an active matrix circuit. Meanwhile, in Figure 2, for convenience, the dimensions of each part and their ratios are exaggerated and may be different from the actual ones. In addition, the materials, dimensions, etc. shown below are examples, and the present invention is not limited to these, and can be appropriately changed without changing the gist. Hereinafter, for convenience of explanation, the upper side of FIG. 2 will be referred to as “upper side” or “upper side,” and the lower side will be referred to as “lower side” or “lower side.” In addition, in FIG. 2, in order to avoid making the drawing complicated, description of hatching indicating the cross section is omitted.

As shown in FIG. 2, the light-emitting element 100 contains an underlying substrate 1, an EL light source portion 200, a filling layer 10, a protective layer 11, and the above-described luminescent particles. It has a structure in which a light conversion layer 12, which acts as a light-emitting layer, and a top plate 13 are stacked in this order.

The EL light source unit 200 includes an anode 2, an EL layer 14 made of a plurality of layers, a cathode 8, a polarizing plate (not shown), and a sealing layer 9 in that order. 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 sequentially stacked from the anode 2 side. ) includes.

This light-emitting element 100 absorbs and re-emits or transmits light generated from the EL light source unit 200 (EL layer 14) by the light conversion layer 12, and transmits it to the outside from the upper plate 13 side. It is a photoluminescence element that extracts light. At this time, it is converted into light of a predetermined color by the luminescent particles included in the light conversion layer 12.

Hereinafter, each layer will be described sequentially.

[Lower board (1) and upper board (13)]

The lower substrate 1 and the upper substrate 13 each have the function of supporting and/or protecting each layer constituting the light emitting device 100. When the light emitting device 100 is a top emission type, the upper substrate 3 is made of a transparent substrate. Meanwhile, when the light emitting device 100 is a bottom emission type, the lower substrate 2 is made of a transparent substrate. Here, a transparent substrate means a substrate capable of transmitting light with a wavelength in the visible light region, and transparency includes colorless transparency, colored transparency, and translucency.

Examples of transparent substrates include glass substrates such as quartz glass and synthetic quartz plates; Quartz substrate; Resin substrates made of polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, polyimide, polycarbonate, etc.; Metal substrates made of iron, stainless steel, aluminum, copper, etc.; Silicon substrates, gallium arsenide substrates, etc. can be used. Among them, a glass substrate made of alkali-free glass that does not contain an alkali component is preferable from the viewpoint of having a small coefficient of thermal expansion and excellent dimensional stability and workability in high-temperature heat treatment. As such glass substrates, for example, "7059 glass", "1737 glass", "Eagle 2000" and "Eagle “10G” and “OA-11” can be used suitably.

There is no particular limitation on the average thickness of the lower substrate 1 and the upper substrate 13, and the range is usually preferably 100 to 1000 μm, and more preferably 300 to 800 μm.

When providing flexibility to the light emitting element 100, a resin substrate or a metal substrate with a relatively small thickness can be selected for the lower substrate 1 and the upper substrate 13, respectively. Meanwhile, depending on the type of use of the light emitting device 100, either or both of the lower substrate 1 and the upper substrate 13 may be omitted.

As shown in FIG. 3, on the lower substrate 1, a signal line driving circuit C1 that controls the supply of current to the anode 2 constituting the pixel electrodes PE indicated by R, G, and B, and A scanning line driving circuit C2, a control circuit C3 that controls the operation of these circuits, a plurality of signal lines 706 connected to the signal line driving circuit C1, and a plurality of signal lines 706 connected to the scanning line driving circuit C2. It is provided with a scanning line (707).

Additionally, as shown in FIG. 4, a condenser 701, a driving transistor 702, and a switching transistor 708 are provided near the intersection of each signal line 706 and each scan line 707.

One electrode of the condenser 701 is connected to the gate electrode of the driving transistor 702, and the other electrode is connected to the source electrode of the driving transistor 702. The driving transistor 702 has a gate electrode connected to one electrode of the condenser 701, a source electrode connected to the other electrode of the condenser 701 and the power line 703 that supplies the driving current, and a drain electrode. It is connected to the anode 2 of the EL light source unit 200.

The switching transistor 708 has a gate electrode connected to the scan line 707, a source electrode connected to the signal line 706, and a drain electrode connected to the gate electrode of the driving transistor 702. Additionally, in this embodiment, the common electrode 705 constitutes the cathode 8 of the EL light source unit 200. Meanwhile, the driving transistor 702 and the switching transistor 708 can be made of, for example, a thin film transistor.

The scan line driving circuit C2 supplies or blocks a scan voltage according to the scan signal to the gate electrode of the switching transistor 708 through the scan line 707, thereby turning the switching transistor 708 on or off. Thereby, the scanning line driving circuit C2 adjusts the timing at which the signal line driving circuit C1 writes the signal voltage. Meanwhile, the signal line driving circuit C1 supplies or blocks a signal voltage according to the image signal to the gate electrode of the driving transistor 702 through the signal line 706 and the switching transistor 708, thereby supplying or blocking a signal voltage according to the image signal to the EL light source unit 200. Adjust the amount of signal current supplied.

Therefore, when the scan voltage is supplied from the scan line driving circuit C2 to the gate electrode of the switching transistor 708 and the switching transistor 708 is turned on, the signal voltage from the signal line driving circuit C1 is supplied to the gate electrode of the switching transistor 708. supplied to the gate electrode. At this time, the drain current corresponding to this signal voltage is supplied to the EL light source unit 200 as a signal current from the power line 703. As a result, the EL light source unit 200 emits light according to the supplied signal current.

<EL light source unit (200)>

[Anode (2)]

The anode 2 has a function of supplying holes from an external power source toward the light emitting layer 5. Constituent materials (anode materials) of the anode 2 include, for example, metals such as gold and aluminum; Halogenated metals such as copper iodide; Metal oxides such as indium tin oxide (ITO), tin oxide (SnO ₂ ), and zinc oxide (ZnO); etc. can be mentioned. These may be used individually, or two or more types may be used together.

There is no particular limitation on the average thickness of the anode 2, and the range is usually preferably 10 to 1000 nm, and more preferably 10 to 200 nm.

The anode 2 can be formed by, for example, a dry film forming method such as vacuum deposition or sputtering. At this time, the anode 2 having a predetermined pattern may be formed by a photolithography method or a method using a mask.

[Cathode (8)]

The cathode 8 has the function of supplying electrons from an external power source toward the light emitting layer 5. Constituent materials (cathode materials) of the cathode 8 include, for example, lithium, sodium, magnesium, aluminum, silver, sodium-potassium alloy, magnesium/aluminum mixture, magnesium/silver mixture, magnesium/indium mixture, and aluminum/aluminum oxide mixture. , rare earth metals, ITO, aluminum-doped zinc oxide (AZO), SnO ₂ , metals or metal oxides such as ZnO. These may be used individually, or two or more types may be used in combination.

There is no particular limitation on the average thickness of the cathode 8, and the range is usually preferably 0.1 to 1000 nm, and more preferably 1 to 200 nm.

The cathode 8 can be formed by, for example, a dry film forming method such as vapor deposition or sputtering.

When the light emitting device 100 is a top emission type, the cathode 8 is composed of a transparent electrode made of ITO or the like. In this case, the anode 2 may be composed of a reflective electrode made of aluminum or the like.

Meanwhile, when the light emitting device 100 is a bottom emission type, the anode 2 is composed of a transparent electrode made of ITO or the like. In this case, the cathode 8 may be composed of a reflective electrode made of aluminum or the like.

[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. Meanwhile, the hole injection layer 3 is formed as needed and may be omitted.

The constituent material (hole injection material) of the hole injection layer 3 includes, for example, phthalocyanine compounds such as copper phthalocyanine; Triphenylamine derivatives such as 4,4',4"-tris[phenyl(m-tolyl)amino]triphenylamine; 1,4,5,8,9,12-hexaazatriphenylenehexacarbonitrile, 2 , 3,5,6-tetrafluoro-7,7,8,8-tetracyano-quinodimethane, metal oxides such as vanadium oxide and molybdenum oxide; polyaniline (emeraldine; ), poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) (PEDOT-PSS), and polypyrrole. These may be used individually or in combination of two or more types. Among them, PEDOT-PSS is more preferable.

The average thickness of the hole injection layer 3 is not particularly limited, and is generally preferably in the range of 0.1 to 500 nm, more preferably in the range of 1 to 300 nm, and even more preferably in the range of 2 to 200 nm. Additionally, the hole injection layer 3 may be a single layer or may have a laminated structure in which two or more layers are stacked.

The hole injection layer 3 can be formed by a wet film forming method or a dry film forming method.

In the wet film forming method, a liquid composition containing a hole injection material is usually applied to an inkjet printing method (piezo method or thermal droplet discharge method), spin coating method, cast method, LB method, plate printing method, gravure printing method, or screen printing method. It is applied by a printing method, nozzle printing method, etc., and the obtained coating film is dried. On the other hand, the nozzle print printing method is a method of applying a liquid composition in a stripe form from a nozzle hole as a liquid column.

As a dry film formation method, vacuum deposition, sputtering, etc. can be suitably 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 them to the light emitting layer 5. Additionally, the hole transport layer 4 may have a function of preventing electron transport. Meanwhile, the hole transport layer 4 may be formed as needed and may be omitted.

As a constituent material (hole transport material) of the hole transport layer 4, it is preferable to use a material with a hole transport ability higher than the electron transport ability. Examples of such hole transport materials include aromatic amines, carbazole derivatives, aromatic hydrocarbons, and stilbene derivatives, and π-electron-excessive heteroaromatics or aromatic amines can be suitably used.

Specific examples of hole transport materials include TPD (N,N'-diphenyl-N,N'-di(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), etc. triphenylamine derivative; 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-dioctylfluorenyl-2,7- Conjugated compound polymers such as diyl)-co-(4,4'-(N-(sec-butylphenyl)diphenylamine))(TFB) and polyphenylenevinylene (PPV), and monomer units thereof; These include copolymers, etc., which may be used individually or in combination of two or more types.

The hole transport material is preferably a triphenylamine derivative, a polymer or copolymer of a triphenylamine derivative into which a substituent is introduced, and a polymer of a triphenylamine derivative into which a substituent is introduced is more preferable.

The average thickness of the hole transport layer 4 is not particularly limited, and is usually preferably in the range of 1 to 500 nm, more preferably in the range of 5 to 300 nm, and even more preferably in the range of 10 to 200 nm.

The hole transport layer 4 may be a single layer or may have a laminated structure in which two or more layers are stacked.

This hole transport layer 4 can be formed by a wet film forming method or a dry film forming method. The wet film forming method and the dry film forming method are as described above in the description of the hole injection layer 3.

[Electron injection layer (7)]

The electron injection layer 7 has a function of receiving electrons supplied from the cathode 8 and injecting them into the electron transport layer 6. Meanwhile, the electron injection layer 7 is formed as needed and may be omitted.

The constituent material (electron injection material) of the electron injection layer 7 includes, for example, alkali metal chalcogenides such as Li ₂ O, LiO, Na ₂ S, Na ₂ 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 8-hydroxyquinolinola lithium (Liq); and alkaline earth metal halides such as CaF ₂ , BaF ₂ , SrF ₂ , MgF ₂ , and BeF ₂ . These may be used individually, or two or more types may be used in combination. Among them, alkali metal chalcogenides, alkaline earth metal halides, and alkali metal salts are preferable.

The average thickness of the electron injection layer 7 is not particularly limited, and is generally preferably in the range of 0.1 to 100 nm, more preferably in the range of 0.2 to 50 nm, and even more preferably in the range of 0.5 to 10 nm. Additionally, the electron injection layer 7 may be a single layer or may have a laminated structure in which two or more layers are stacked.

The electron injection layer 7 can be formed by a wet film forming method or a dry film forming method. The wet film forming method and the dry film forming method are as described above in the description of the hole injection layer 3.

[Electron transport layer (6)]

The electron transport layer 6 has a function of receiving electrons from the electron injection layer 7 and efficiently transporting them to the light emitting layer 5. Additionally, the electron transport layer 6 may have a function of preventing transport of holes. Meanwhile, the electron transport layer 6 may be formed as needed and may be omitted.

As a constituent material (electron transport material) of the electron transport layer 6, it is preferable to use a material with a higher electron transport ability than a hole transport ability. Electron transport materials include, for example, fullerenes, diphenylquinone derivatives, nitro-substituted fluorene derivatives, quinoxaline derivatives, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, pyridine derivatives, bipyridine derivatives, imidazole derivatives, π electron-deficient heteroaromatics such as nitrogen-containing heteroaromatic compounds such as quinoline derivatives, perylene derivatives, triazine derivatives, or pyrimidine derivatives; and metal complexes having a quinoline ligand, perylene ligand, benzoquinoline ligand, oxazole ligand, benzoxazoline ligand, benzothiazoline ligand, or thiazole ligand.

Specific examples of electron transport materials include tris(8-quinolinolate)aluminum (Alq), tris(4-methyl-8-quinolinoleto)aluminum (Almq3), and bis(10-hydroxybenzo[h]quinone). Nolinato) beryllium, bis (2-methyl-8-quinolinoleto) (p-phenylphenolate) aluminum, bis (8-quinolinoleto) zinc, bis [2- (2'-hydroxyphenyl) )benzoxazolato]zinc, bis[2-(2'-hydroxyphenyl)benzothiazolato]zinc, 2-(4-biphenylyl)-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]carbazole (CO11), 2,2',2"-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole)( TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (mDBTBIm-Ⅱ), 4,7-diphenyl-1,10-phenanthroline (BPhen) etc. can be mentioned. These compounds may be used individually or in combination of two or more types.

Additionally, as an electron transport material, an inorganic semiconductor material may be used. By constructing the electron transport layer 6 from an inorganic semiconductor material, the mobility of electrons in the electron transport layer 6 can be increased, and the efficiency of electron injection into the light emitting layer 5 can be improved. Examples of such electron transport materials include metal salts such as cesium carbonate; Metal oxides such as titanium oxide (TiOx) and zinc oxide can be suitably used.

There is no particular limitation on the average thickness of the electron transport layer 6, and the range is usually preferably 5 to 500 nm, and more preferably 5 to 200 nm. Additionally, the electron transport layer 6 may be a single layer or may have a laminated structure in which two or more layers are stacked.

The electron transport layer 6 can be formed by a wet film forming method or a dry film forming method. The wet film forming method and the dry film forming method are as described above in the description of the hole injection layer 3.

By forming the hole injection layer 3 and the electron injection layer 7 in the light emitting device 100, the transport efficiency of holes and electrons to the light emitting layer 5 through the hole transport layer 4 and the electron transport layer 6 will be increased. You can. As a result, the luminous efficiency of the light-emitting layer 5 is further improved, and a light-emitting element that can emit light at high brightness and has a long lifespan is obtained.

[Luminous layer (5)]

The light-emitting layer 5 has a function of generating light emission using energy generated by recombination of holes and electrons injected into the light-emitting layer 5. The light-emitting layer 5 of this embodiment emits blue light with a wavelength in the range of 400 to 500 nm, and more preferably in the range of 420 to 480 nm.

The light-emitting layer 5 preferably contains a light-emitting material (guest material or dopant material) and a host material. There is no particular limitation on the mass ratio between the host material and the light-emitting material, and a range of usually 10:1 to 300:1 is preferable.

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 may be used, and may be selected from the group consisting of organic low molecule fluorescent materials, organic polymer fluorescent materials, and organic phosphorescent materials. It is preferable to include at least one type.

Compounds that can convert singlet excitation energy into light include organic low-molecular-weight fluorescent materials or organic polymer fluorescent materials that emit fluorescence.

Organic low-molecular-weight fluorescent materials include anthracene structure, tetracene structure, chrysene structure, phenanthrene structure, pyrene structure, perylene structure, stilbene structure, acridone structure, coumarin structure, phenoxazine structure, or phenothiazine structure. Compounds having

Specific examples of organic low-molecular-weight fluorescent materials include, for example, 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine, 5,6-bis[4'- (10-phenyl-9-anthryl)biphenyl-4-yl]-2,2'-bipyridine, N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N, N'-diphenylstilbene-4,4'-diamine, 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine, 4-(9H- Carbazol-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine, N,9-diphenyl-N-[4-(10-phenyl-9-anthryl) Phenyl]-9H-carbazol-3-amine, 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine, 4-[4 -(10-phenyl-9-anthryl)phenyl]-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine, perylene, 2,5,8,11-tetra (tert- Butyl)perylene, N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine, N,N' -bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]-pyrene-1,6-diamine, N,N'-bis(di Benzofuran-2-yl)-N,N'-diphenylpyrene-1,6-diamine, N,N'-bis(dibenzothiophen-2-yl)-N,N'-diphenylpyrene-1 ,6-diamine, N,N"-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis[N,N',N'-triphenyl-1,4-phenyl lendiamine], N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazol-3-amine, N-[4-(9,10 -diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine, N,N,N',N',N",N",N"' ,N"'-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine, coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9 -Diphenyl-9H-carbazol-3-amine, N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl-1,4-phenylenediamine, N, N,9-triphenylanthracene-9-amine, coumarin 6, coumarin 545T, N,N'-diphenylquinacridone, rubrene, 5,12-bis(1,1'-biphenyl-4-yl) -6,11-diphenyltetracene, 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-ylidene)propandinitrile, 2- {2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene }Propanedinitrile, 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]fluoranthene-3,10-diamine, 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl- 2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propandinitrile, 2-{2-tert -Butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl] -4H-pyran-4-ylidene}propandinitrile, 2-(2,6-bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propandinitrile , 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoli gin-9-yl)ethenyl]-4H-pyran-4-ylidene}propandinitrile, 5,10,15,20-tetraphenylbisbenzo[5,6]indeno[1,2,3-cd :1',2',3'-lm] perylene, etc.

Organic polymer fluorescent materials include, for example, homopolymers made up of units based on fluorene derivatives, copolymers made up of units based on fluorene derivatives and units based on tetraphenylphenylenediamine derivatives, and fluorescent substances based on terphenyl derivatives. Examples include homopolymers made of units, homopolymers made of units based on diphenylbenzofluorene derivatives, etc.

As a compound capable of converting triplet excitation energy into light, an organic phosphorescent material that emits phosphorescence is preferable. Examples of organic phosphorescent materials include metal complexes containing at least one metal atom selected from the group consisting of Ir, Rh, Pt, Ru, Os, Sc, Y, Gd, Pd, Ag, Au, and Al. You can. Among them, a metal complex containing at least one metal atom selected from the group consisting of Ir, Rh, Pt, Ru, Os, Sc, Y, Gd and Pd is preferred, and a metal complex consisting of Ir, Rh, Pt and Ru A metal complex containing at least one metal atom selected from the group is more preferable, and an Ir complex or a Pt complex is more preferable.

The light emitting layer 5 may contain a host material. The host material provides a field for recombination of holes and electrons injected into the light emitting layer 5 and promotes the formation of hole-electron pairs (exciton) on the molecule. The excitation energy of this exciton moves to the nanocrystal (Förster resonance energy transfer) and emits light. By utilizing this phenomenon, the luminous efficiency of the light emitting layer 5 can be improved.

As the host material, it is preferable to use at least one type of compound having an energy gap larger than that of the light-emitting material. Additionally, when the light-emitting material is a phosphorescent material, it is preferable to select a compound with a triplet excitation energy (energy difference between the ground state and the triplet excited state) larger than the host material than the light-emitting material.

Host materials include, for example, Alq, Almq3, bis(10-hydroxybenzo[h]quinolinato)beryllium(II), and bis(2-methyl-8-quinolinolato)(4-phenylphenolate). ) Aluminum (III), bis (8-quinolinoleto) zinc (II), bis [2- (2-benzooxazolyl) phenolate] zinc (II), bis [2- (2-benzothiazolyl) Phenolato]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-butylphenyl)-1,2 ,4-triazole, 2,2',2"-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole), vasophenanthroline, vasocuproine, 9- [4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole, 9,10-diphenylanthracene, N,N-diphenyl-9-[4- (10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine, 4-(10-phenyl-9-anthryl)triphenylamine, N,9-diphenyl-N-{4- [4-(10-phenyl-9-anthryl)phenyl]phenyl}-9H-carbazol-3-amine, 6,12-dimethoxy-5,11-diphenylchrysene, 9-[4-(10 -phenyl-9-anthracenyl)phenyl]-9H-carbazole, 3,6-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole, 9-phenyl- 3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole, 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g] Carbazole, 6-[3-(9,10-diphenyl-2-anthryl)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-di(2-naphthyl)anthracene , 2-tert-butyl-9,10-di(2-naphthyl)anthracene, 9,9'-bianthryl, 9,9'-(stilbene-3,3'-diyl)diphenanthrene, 9, 9'-(stilbene-4,4'-diyl)diphenanthrene, 1,3,5-tri(1-pyrenyl)benzene, 5,12-diphenyltetracene or 5,12-bis(biphenyl) -2-yl) Tetracene and the like may be used individually or in combination of two or more types.

The average thickness of the light emitting layer 5 is usually preferably in the range of 1 to 100 nm, and more preferably in the range of 1 to 50 nm.

The light emitting layer 5 can be formed by a wet film forming method or a dry film forming method. The wet film forming method and the dry film forming method are as described above in the description of the hole injection layer 3.

On the other hand, the EL light source unit 200 may further have, for example, a bank (partition) that partitions 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, and is generally preferably in the range of 0.1 to 5 μm, more preferably in the range of 0.2 to 4 μm, and even more preferably in the range of 0.2 to 3 μm.

The width of the opening of the bank is preferably in the range of 10 to 200 μm, more preferably in the range of 30 to 200 μm, and even more preferably in the range of 50 to 100 μm. The length of the bank opening is preferably in the range of 10 to 400 μm, more preferably in the range of 20 to 200 μm, and even more preferably in the range of 50 to 200 μm.

Additionally, the bank inclination angle is preferably in the range of 10 to 100 degrees, more preferably in the range of 10 to 90 degrees, and even more preferably in the range of 10 to 80 degrees.

The light emitting element 100 may further have a hole blocking layer between the light emitting layer 5 and the electron transport layer 6. The hole blocking layer has a function of regulating the movement of holes transported from the hole transport layer 4 through the light emitting layer 5 to the electron transport layer 6. By forming a hole block layer, holes that were unable to recombine with electrons in the light-emitting layer 5 can be allowed to stay in the light-emitting layer 5 instead of escaping into the electron transport layer 6. Since the holes remaining in the light-emitting layer 5 have the opportunity to recombine with electrons again, they are not wasted, and the luminous efficiency of the light-emitting layer 5 can be further improved.

As a constituent material of the hole blocking layer, the above-described electron transport materials can be used individually or in combination of two or more types.

The average thickness of the hole blocking layer is not particularly limited, and is usually preferably in the range of 1 to 500 nm, more preferably in the range of 2 to 300 nm, and even more preferably in the range of 3 to 200 nm. Additionally, the hole blocking layer may be a single layer or may have a laminated structure in which two or more layers are stacked.

The hole blocking layer can be formed by a wet film forming method or a dry film forming method. The wet film forming method and the dry film forming method are as described above in the description of the hole injection layer 3.

Additionally, the light emitting element 100 may further include a reflective layer for appropriately reflecting light, a transparent optical adjustment layer for appropriately transmitting light, and a light scattering layer for appropriately transmitting and scattering light.

The embodiment of the light emitting element 100 is not limited to the above-described configuration, and may further include any other configuration, or may be replaced with any configuration that performs the same function.

<Light conversion layer (12)>

The light conversion layer 12 converts the light generated from the EL light source unit 200 and re-emits it, or transmits the light generated from the EL light source unit 200.

As shown in FIG. 2, the light conversion layer is a pixel unit 20, which includes a first pixel unit 20a that converts light with a wavelength in the above range to emit red light, and a first pixel unit 20a that converts light with a wavelength in the above range to emit red light. It has a second pixel portion 20b that emits green light, and a third pixel portion 20c that transmits light with a wavelength in the above range. A plurality of first pixel portions 20a, second pixel portions 20b, and third pixel portions 20c are arranged in a grid so that this order is repeated. And, between adjacent pixel units, that is, between the first pixel unit 20a and the second pixel unit 20b, between the second pixel unit 20b and the third pixel unit 20c, and between the third pixel unit 20c. ) and the first pixel portion 20a, a light blocking portion 30 that blocks light is provided. In other words, adjacent pixel portions 20 are spaced apart from each other by the light blocking portion 30 . Additionally, the first pixel portion 20a and the second pixel portion 20b may contain colorants corresponding to each color.

The first pixel portion 20a and the second pixel portion 20b are light-emitting pixel portions each formed of the composition described above. Here, the first pixel portion 20a and the second pixel portion 20b contain luminescent particles and a thermoplastic resin, and preferably further contain light-scattering particles in order to scatter light and reliably extract it to the outside.

The first pixel portion 20a includes a first resin component 22a, and first luminescent particles 90a and first light scattering particles 21a dispersed in the first resin component 22a. Similarly, the second pixel portion 20b includes the second resin component 22b, and the second luminescent particles 90b and second light scattering particles 21b dispersed in the second resin component 22b.

Here, the resin component is a component mainly composed of a thermoplastic resin, and may contain organic components (dispersants, etc.) in the composition.

In the first pixel portion 20a and the second pixel portion 20b, the first resin component 22a and the second resin component 22b may be the same or different, and the first light scattering particles 21a and the second resin component 22b may be the same or different. 2 The light scattering particles 21b may be the same or different.

The first luminescent particle 90a is a red luminescent particle that absorbs light with a wavelength in the range of 420 to 480 nm and emits light with a peak wavelength of the luminescence spectrum in the range of 605 to 665 nm. That is, the first pixel unit 20a can be said to be a red pixel unit for converting blue light into red light.

Additionally, the second luminescent particles 90b are green luminescent particles that absorb light with a wavelength in the range of 420 to 480 nm and emit light with a peak wavelength of the luminescence spectrum in the range of 500 to 560 nm. That is, the second pixel unit 20b can be said to be a green pixel unit for converting blue light into green light.

The content of luminescent particles in the pixel portions 20a and 20b is 0.1% by mass or more based on the total mass of solids in the composition from the viewpoint of improving the external quantum efficiency and obtaining excellent luminous intensity. It is preferable, 1 mass% or more is more preferable, 2 mass% or more is still more preferable, and 3 mass% or more is especially preferable. The content of the luminescent particles is preferably 30% by mass or less, and 25% by mass or less, based on the total mass of solids in the composition, from the viewpoint of excellent reliability of the pixel portions 20a and 20b and from the viewpoint of obtaining excellent luminous intensity. is more preferable, 20 mass% or less is further preferable, and 15 mass% or less is especially preferable.

The content of light scattering particles in the pixel portions 20a, 20b is preferably 0.1% by mass or more, and more preferably 0.5% by mass or more, based on the mass of the luminescent particles, from the viewpoint of better improvement in external quantum efficiency. It is preferable, 1 mass% or more is more preferable, and 3 mass% or more is especially preferable. The content of light scattering particles is preferably 5% by mass or less, and is 10% by mass, based on the mass of the luminescent particles, from the viewpoint of superior improvement in external quantum efficiency and excellent reliability of the pixel portion 20. Less is more preferable, 15 mass% or less is more preferable, and 20 mass% or less is particularly preferable.

The third pixel portion 20c has a transmittance of 30% or more for light with a wavelength in the range of 420 to 480 nm. Therefore, the third pixel portion 20c functions as a blue pixel portion when using a light source that emits light with a wavelength in the range of 420 to 480 nm. The third pixel portion 20c is, for example, a non-luminescent composition formed of a composition (non-luminescent composition) having the same composition as the composition of the above-described embodiment except that it does not contain the luminescent particles constituting the dispersion of the present invention. This is the pixel unit. The third pixel portion 20c does not contain light-emitting particles, but contains light-scattering particles and thermoplastic resin. That is, the third pixel portion 20c includes the third resin component 22c and the third light scattering particles 21c dispersed in the third resin component 22c.

The third resin component 22c is, for example, a component mainly composed of a thermoplastic resin. The third resin component 22c may contain a thermoplastic resin and an organic component (dispersant, etc.) in the composition as long as the transmittance for light with a wavelength in the range of 420 to 480 nm is 30% or more.

The third light-scattering particles 21c may be the same as or different from the first light-scattering particles 21a and the second light-scattering particles 21b.

The content of light scattering particles in the pixel portion 20c is preferably 1% by mass or more, and 3% by mass or more, based on the total mass of solids in the non-luminescent composition, from the viewpoint of further reducing the light intensity difference at the viewing angle. This is more preferable, and 5% by mass or more is further preferable. From the viewpoint of further reducing light reflection, the content of light scattering particles is preferably 80% by mass or less, more preferably 75% by mass or less, and even more preferably 70% by mass or less, based on the total mass of solids in the non-luminescent composition. desirable.

Meanwhile, the transmittance of the third pixel portion 20c can be measured using a microspectroscopy device.

The thickness of the pixel portion (the first pixel portion 20a, the second pixel portion 20b, and the third pixel portion 20c) is preferably 1 μm or more, more preferably 2 μm or more, and 3 μm or more. It is more desirable.

The thickness of the pixel portion (the first pixel portion 20a, the second pixel portion 20b, and the third pixel portion 20c) is preferably 20 μm or less, more preferably 15 μm or less, and 10 μm or less. It is more desirable.

The light blocking portion 30 is a partition wall portion, a so-called black matrix, installed for the purpose of separating adjacent pixel portions 20 to prevent color mixing (crosstalk) and to prevent light leakage from a light source.

The material constituting the light-shielding portion 30 is not particularly limited, and includes, in addition to metals such as chromium, a resin composition containing binder resin and light-shielding particles such as carbon particles, metal oxides, inorganic pigments, and organic pigments. . Binder resins include, for example, resins containing one or more types of polyimide resin, acrylic resin, epoxy resin, polyacrylamide, polyvinyl alcohol, gelatin, casein, cellulose, photosensitive resin, O/W emulsion resin ( For example, reactive silicone emulsion) can be used.

The thickness of the light blocking portion 30 is preferably 1 μm or more and 15 μm or less.

[Method of forming light conversion layer 12]

The light conversion layer 12 having the above first to third pixel portions 20a to 20c can be formed, for example, by drying and heating a coating film formed by a wet film forming method. The first pixel portion 20a and the second pixel portion 20b can be formed using the composition of the present invention, and the third pixel portion 20c includes luminescent particles constituting the dispersion of the present invention. It can be formed using the non-luminescent composition described above.

Application methods for obtaining a coating film of the composition of the present invention include inkjet printing (piezo or thermal droplet discharge), spin coating, casting, LB, plate printing, gravure printing, and screen printing. , nozzle print printing method, etc.

In the case of the inkjet printing method, the discharge amount of the composition is not particularly limited, and is usually preferably 1 to 50 pL/time, more preferably 1 to 30 pL/time, and even more preferably 1 to 20 pL/time.

The opening 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. Within this range, the ejection precision of the composition can be increased while preventing the nozzle hole from clogging.

The temperature at the time of forming the coating film is not particularly limited, and is usually preferably in the range of 10 to 50°C, more preferably in the range of 15 to 40°C, and even more preferably in the range of 15 to 30°C. When liquid droplets are discharged at this temperature, crystallization of various components contained in the composition of the present invention can be suppressed.

Additionally, the relative humidity when forming the coating film is not particularly limited, and is generally preferably in the range of 0.01 ppm to 80%, more preferably in the range of 0.05 ppm to 60%, and even more preferably in the range of 0.1 ppm to 15%. Preferred, the range of 1 ppm to 1% is particularly preferable, and the range of 5 to 100 ppm is most preferable.

When hydrocarbons, halogenated hydrocarbons, ethers, alcohols, ketones, esters, aprotic polar compounds, etc. are added to the composition as solvents, the composition is applied on a substrate and then dried naturally, under heating, or under reduced pressure. From the viewpoint of productivity, it is preferable to perform drying under heating or under heating and reduced pressure. The heating temperature is usually preferably 50 to 130°C, more preferably 60 to 120°C, considering the boiling point and vapor pressure of the added solvent. The pressure under reduced pressure is usually preferably in the range of 0.001 to 100 Pa. Additionally, the drying time is usually preferably 1 to 30 minutes. By removing the solvent from the coating film by drying, the external quantum efficiency of the resulting light conversion layer can be further improved.

As described above, the composition of the present invention has little change in luminescence characteristics, is excellent in long-term storage and storage stability, and can realize good luminescence even in the pixel portion 20, which is a molded body (coated film). Additionally, since the composition of the present invention has excellent dispersibility, the dispersibility of the luminescent particles is excellent, and it is easy to obtain a flat pixel portion 20.

In addition, when the light-emitting particles included in the first pixel portion 20a and the second pixel portion 20b include semiconductor nanocrystals having a perovskite-type crystal structure, absorption in the wavelength range of 300 to 500 nm is observed. is big. Therefore, in the first pixel portion 20a and the second pixel portion 20b, the blue light incident on the first pixel portion 20a and the second pixel portion 20b transmits toward the upper plate 13. In other words, blue light can be prevented from leaking toward the upper plate 13. Therefore, according to the first pixel portion 20a and the second pixel portion 20b containing the luminescent particles constituting the dispersion of the present invention, red light and green light with high color purity can be extracted without mixing blue light. there is.

The light emitting element 100 may be configured as a bottom emission type instead of a top emission type. Additionally, the light emitting device 100 may use another light source instead of the EL light source unit 200.

The above-described light emitting element is suitable for application to a color display device equipped with a color filter. Here, a color display device is a device that performs color display, such as a television, monitor, smartphone, or mobile phone, and includes both types that do not use a liquid crystal layer and types that use a liquid crystal layer.

Although the dispersion of the present invention, the composition containing the dispersion, and the light conversion layer formed from the composition have been described above, the present invention is not limited to the configuration of the above-described embodiment. For example, the dispersion of the present invention, the composition containing the dispersion, and the light conversion layer formed from the composition may each have other arbitrary components in addition to the configuration of the above-described embodiment, and exhibit the same function. It may be substituted with any configuration.

Example

Hereinafter, the present invention will be described in detail through examples. However, the present invention is not limited to the following examples. Meanwhile, unless otherwise specified, “part” and “%” are based on mass.

A. Preparation examples of various luminescent particle dispersions with different moisture content

Comparative Example 1

First, 0.12 g of cesium carbonate, 5 mL of 1-octadecene, and 0.5 mL of oleic acid were mixed and uniformly dissolved at 150°C in an argon atmosphere, and then cooled to 100°C to obtain a cesium-oleic acid solution. .

Meanwhile, 0.1 g of lead(II) bromide, 7.5 mL of 1-octadecene, and 0.75 mL of oleic acid were mixed, dried under reduced pressure at 90°C for 10 minutes in an argon atmosphere, and then added with 0.75 mL of 3-aminopropyltri. Ethoxysilane (APTES) was added and dried under reduced pressure while stirring for an additional 20 minutes, and then heated to 140°C.

To the mixed solution containing lead(II) bromide, 0.75 mL of the cesium-oleic acid solution was added at 150°C, stirred for 5 seconds, and then cooled in an ice bath. Next, 30 mL of methyl acetate was added, the mixture was shaken and the resulting suspension was centrifuged (10000 rpm, 1 minute). 1.13 g of toluene was added to the precipitate obtained by removing the supernatant, and the supernatant was recovered, thereby producing perovskite-type CsPbBr ₃ (which has a surface layer coordinated by oleic acid and containing siloxane bonds between APTES). (hereinafter referred to as “QD1”) was dispersed in toluene at a concentration of 0.1% by mass to obtain dispersion C1. The moisture content in dispersion C1 was measured by the Karl Fischer method and was found to be 0.004%. The ratio (mass ratio) of water to QD1 in dispersion C1 is equivalent to 0.04.

Comparative Example 2

5% of Molecular Sieve 3A based on the weight of the dispersion was added to dispersion C1, mixed by shaking, and left to stand for 24 hours. Molecular Sieve 3A acts as a dehydrating agent. Next, dispersion C2 was obtained by filtration with a membrane filter (pore diameter 5.0 μm). The moisture content in dispersion C2 was measured by the Karl Fischer method and was found to be 0.003%. The ratio of water to QD1 in dispersion C2 is equivalent to 0.03.

Example 1

Dispersion 1 was obtained by adding pure water to dispersion C1 obtained by the method of Comparative Example 1 and stirring vigorously so that the mass ratio of water to QD1 was 1.0. The moisture content in dispersion 1 was measured by the Karl Fischer method and was found to be 0.117%.

Example 2

To dispersion C1 obtained by the method of Comparative Example 1, pure water was added so that the ratio of water to QD1 was 5.0 and stirred vigorously to obtain dispersion 2. The moisture content in dispersion 2 was measured by the Karl Fischer method and was found to be 0.576%.

Example 3

Dispersion 3 was obtained by adding pure water to dispersion C1 obtained by the method of Comparative Example 1 and stirring vigorously so that the mass ratio of water to QD1 was 7.5. The moisture content in dispersion 3 was measured by the Karl Fischer method and was found to be 0.860%.

Comparative Example 3

In Example 1, when preparing a mixed solution containing lead (II) bromide, the same procedure as in Preparation Example 1 was performed except that oleylamine was added instead of APTES, and oleic acid and oleylamine were coordinated. Dispersion C3 was obtained in which louvskite-type CsPbBr ₃ (hereinafter referred to as “QD2”) was dispersed in toluene at a concentration of 0.1% by mass. The moisture content in dispersion C3 was measured by the Karl Fischer method and was found to be 0.004%. The ratio of water to QD2 (mass ratio) in dispersion C3 is equivalent to 0.04.

Comparative Example 4

To dispersion C1 obtained by the method of Comparative Example 1, pure water was added so that the mass ratio of water to QD1 was 10.9 and stirred vigorously to obtain dispersion C4. The moisture content in dispersion C4 was measured by the Karl Fischer method and was found to be 1.249%.

Comparative Example 5

To dispersion C3 obtained by the method of Comparative Example 3, pure water was added so that the mass ratio of water to QD2 was 4.2 and stirred vigorously to obtain dispersion C5. The moisture content in dispersion C5 was measured by the Karl Fischer method and was found to be 0.480%.

Comparative Example 6

To dispersion C3 obtained by the method of Comparative Example 3, pure water was added so that the mass ratio of water to QD2 was 10.1 and stirred vigorously to obtain dispersion C6. The moisture content in dispersion C6 was measured by the Karl Fischer method and was found to be 1.161%.

Comparative Example 7

To dispersion C3 obtained by the method of Comparative Example 3, pure water was added so that the mass ratio of water to QD2 was 47.6 and stirred vigorously to obtain dispersion C7. The moisture content in dispersion C7 was measured by the Karl Fischer method and was found to be 5.476%.

Comparative Example 8

To dispersion C3 obtained by the method of Comparative Example 3, pure water was added so that the mass ratio of water to QD2 was 90.3 and stirred vigorously to obtain dispersion C8. The moisture content in dispersion C8 was measured by the Karl Fischer method and was found to be 10.394%.

Comparative Example 9

To dispersion C3 obtained by the method of Comparative Example 3, pure water was added so that the mass ratio of water to QD2 was 319.0 and stirred vigorously to obtain dispersion C9. The moisture content in dispersion C9 was measured by the Karl Fischer method and was found to be 36.697%.

B. Storage stability of dispersion of each luminescent particle

For each dispersion obtained above, the absolute quantum yield (PLQY), peak wavelength (λmax) of the emission spectrum, and luminescence of each dispersion immediately after preparation and after storage at 40°C for 1 day, 25 days, and 70 days, respectively. The full width at half maximum (FWHM) of the spectrum was measured using an absolute PL quantum yield measuring device (“Quantaurus-QY” manufactured by Hamamatsu Hotonics) at an excitation wavelength of 450 nm.

The results are shown in Table 1.

The dispersions of Examples 1 to 3 contain luminescent particles having a surface layer containing a structure having a siloxane bond on the surface of a semiconductor nanocrystal made of metal halide, and the water content is within the range of 0.10% to 1.0%. . As shown in Table 1, the dispersions of Examples 1 to 3 all have PLQYs exceeding 50% after 70 days of storage, and not only do they have sufficient quantum efficiency, but λmax and FWHM after 70 days of storage are similar to those immediately after preparation. It's the same degree. From this, it is clear that the dispersions of Examples 1 to 3 are not only excellent in durability but also have excellent long-term stability.

On the other hand, the dispersions of Comparative Examples 1, 2, and 3 contain luminescent particles having a surface layer containing a structure having a siloxane bond on the surface of a semiconductor nanocrystal made of metal halide, but the water content is less than 0.10% or 1.0%. It is excess. As shown in Table 1, the dispersions of Comparative Examples 1, 2, and 3 all have PLQYs of 40% or less after storage for 70 days, and cannot be said to have sufficient quantum efficiency. Therefore, it is clear that the dispersions of Comparative Examples 1, 2, and 3 have insufficient long-term stability.

Additionally, the dispersion of Comparative Example 5 contains luminescent particles having a surface layer on the surface of semiconductor nanocrystals made of metal halide, and has a moisture content within the range of 0.10% to 1.0%. However, the surface layer of the luminescent particle does not include a structure having a siloxane bond. As shown in Table 1, the dispersion of Comparative Example 5 has a PLQY of 40% or less after 70 days of storage, and not only does it not have a sufficient quantum yield, but also λmax after 70 days of storage is significantly toward the short wavelength side compared to immediately after preparation. By shifting, the FWHM after 70 days of storage became wider compared to immediately after preparation. From this, it is clear that the dispersion of Comparative Example 5 is poor in durability and long-term stability.

In addition, the dispersions of Comparative Examples 6 to 9 did not have a moisture content within the range of 0.10% to 1.0%, and the surface layer of the luminescent particles did not contain a structure having siloxane bonds. As shown in Table 1, the dispersions of Comparative Examples 6 to 9 had PLQYs significantly below 40% after storage for 70 days, not only did they not have sufficient quantum yields, but also λmax after storage for 70 days was lower than that immediately after preparation. As a result, there was a significant shift toward the short wavelength side, and the FWHM after 70 days of storage became wider compared to immediately after preparation. From this, it is clear that the dispersions of Comparative Examples 6 to 9 are poor in durability and long-term stability.

C. Fabrication of light conversion layer

In the following example, a composition containing the dispersion of each luminescent particle obtained above and a thermoplastic resin was prepared, and a light conversion layer was formed from this composition.

Details of the thermoplastic resin used are shown below.

PMMA: polymethyl methacrylate (manufactured by Sigma-Aldrich, Mw=120,000)

PS: Polystyrene (manufactured by Sigma-Aldrich, Mw=280,000)

CAB: Cellulose acetate butyrate (manufactured by EASTMAN CHEMICAL, Mw=70,000)

PC: Polycarbonate (manufactured by Idemitsu Kosan Corporation, brand name “Taflon MD1500”)

Example 4

PMMA was dissolved in toluene at 60°C to prepare a PMMA solution with a concentration of 20 mass%. Composition 1 was prepared by mixing 1.0 g of this PMMA solution with 1.1 g of dispersion 1 immediately after preparation and shaking it.

Composition 1 was dropped onto a glass substrate, applied in the air with a spin coater so that the dried film thickness was 100 μm, and dried at 60°C for 15 minutes to form light conversion layer 1 containing QD1.

In addition, dispersion 1 stored at 40°C for 1 day, that is, dispersion 1 that had passed 1 day in the storage stability test described above, was used and the light conversion layer 2 containing QD1 was formed in the same manner as above.

In addition, dispersion 1 stored at 40°C for 25 and 70 days, that is, dispersion 1 after 25 and 70 days in the above storage stability test, was used, and in the same manner as above, photoconversion containing QD1 was performed. Layer 3 and light conversion layer 4 were formed, respectively.

Example 5

In Example 4, composition 2 was prepared in the same manner as in Example 4, except that dispersion 2 was used instead of dispersion 1, and light conversion layers 1 to 4 containing QD1 were formed. .

Example 6

In Example 4, composition 3 was prepared in the same manner as in Example 4, except that dispersion 3 was used instead of dispersion 1, and light conversion layers 1 to 4 containing QD1 were formed. .

Comparative Example 10

In Example 4, composition C1 was prepared in the same manner as in Example 4, except that 1.2 g of dispersion C1 was used instead of dispersion 1, and light conversion layers 1 to 4 containing QD1 were prepared. was formed.

Comparative Example 11

In Comparative Example 10, composition C2 was prepared in the same manner as in Example 4, except that 1.2 g of dispersion C2 was used instead of dispersion C1, and light conversion layers 1 to 4 containing QD2 were prepared. were formed respectively.

Comparative Example 12

In Comparative Example 10, composition C3 was prepared in the same manner as in Example 4, except that 1.1 g of dispersion C3 was used instead of dispersion C1, and light conversion layers 1 to 4 containing QD1 were prepared. were formed respectively.

Comparative Example 13

In Comparative Example 10, composition C4 was prepared in the same manner as in Example 4, except that 1.3 g of dispersion C4 was used instead of dispersion C1, and light conversion layers 1 to 4 containing QD2 were prepared. were formed respectively.

Comparative Example 14

In Comparative Example 10, composition C5 was prepared in the same manner as in Example 4, except that 1.6 g of dispersion C6 was used instead of dispersion C1, and light conversion layers 1 to 4 containing QD2 were prepared. were formed respectively.

Example 7

PS was dissolved in toluene at 60°C to prepare a PS solution with a concentration of 20 mass%. 1.0 g of this PS solution was mixed with 1.1 g of dispersion 2 immediately after preparation, and composition 4 was prepared by shaking with shaking.

Composition 4 was dropped onto a glass substrate, applied in the air with a spin coater so that the dried film thickness was 100 μm, and dried at 60°C for 15 minutes to form light conversion layer 1 containing QD1.

Dispersion 2 stored at 40°C for 1 day, that is, dispersion 2 that had passed 1 day in the storage stability test above, was used, and in the same manner as above, light conversion layer 2 containing QD1 was formed.

In addition, dispersion 2 stored at 40°C for 25 and 70 days, that is, dispersion 2 after 25 and 70 days in the above storage stability test, was used, and in the same manner as above, photoconversion containing QD1 was performed. Layer 3 and light conversion layer 4 were formed.

Example 8

In Example 7, light conversion layers 1 to 4 containing QD1 were formed in the same manner as in Example 7, except that dispersion 3 was used instead of dispersion 2.

Example 9

In Example 7, light conversion layers 1 to 4 containing QD1 were formed in the same manner as in Example 7, except that CAB was used instead of PS.

Example 10

In Example 7, light conversion layers 1 to 4 containing QD1 were formed in the same manner as in Example 7, except that PC was used instead of PS.

D. Evaluation of optical properties of light conversion layer

Light conversion layer 1 (formed from the dispersion immediately after preparation), light conversion layer 2 (formed from the dispersion after storage for 1 day at 40°C), and light conversion layer 3, respectively formed in Examples 4 to 10 and Comparative Examples 10 to 14. (Formed from dispersion after storage at 40°C for 25 days), light conversion layer 4 (Formed from dispersion after storage at 40°C for 70 days), absolute quantum yield (PLQY), peak wavelength of emission spectrum (λmax), and emission spectrum. The full width at half maximum (FWHM) was measured using an absolute PL quantum yield measuring device (“Quantaurus-QY” manufactured by Hamamatsu Hotonics) at an excitation wavelength of 450 nm.

The results are shown in Table 2.

The compositions of Examples 4 to 10 contain any one of the dispersions of Examples 1 to 3. Even if the light conversion layer formed from the composition of Examples 4 to 10 is a light conversion layer formed using a composition containing the dispersion after storage for 70 days, λmax and FWHM are compositions containing the dispersion immediately after preparation. It is the same as the light conversion layer formed using . From this, it is clear that the dispersions of Examples 1 to 3 exhibit excellent optical properties even when prepared as a composition after storage for 70 days and a light conversion layer is formed using the composition.

Meanwhile, the composition of Comparative Example 10 includes the dispersion of Comparative Example 1. The light conversion layer formed from the composition of Comparative Example 10 had λmax and FWHM of the light conversion layer formed using a composition containing the dispersion after storage for 70 days. It was formed using a composition containing the dispersion immediately after preparation. It is inferior to one light conversion layer. As shown in Table 1, the PLQY of the dispersion after 70 days of storage is 40%, and the performance as a dispersion is insufficient, so the optical properties of the light conversion layer are poor.

Additionally, the composition of Comparative Example 11 includes the dispersion of Comparative Example 2. The light conversion layer formed from the composition of Comparative Example 11 had λmax and FWHM of the light conversion layer formed using a composition containing the dispersion after storage for 70 days. It was formed using a composition containing the dispersion immediately after preparation. It is inferior to one light conversion layer. As shown in Table 1, the PLQY of the dispersion after 70 days of storage is 40%, and the performance as a dispersion is insufficient, so the optical properties of the light conversion layer are poor.

Additionally, the compositions of Comparative Examples 12 to 14 contain any one of the dispersions of Comparative Examples 3, 4, and 6. The compositions of Comparative Examples 12 to 14 have λmax and FWHM of the light conversion layer formed using a composition containing the dispersion after storage for 70 days, and the light conversion layer formed using the composition containing the dispersion immediately after preparation. It was greatly reduced compared to .

From this, when the dispersions of Comparative Examples 10 to 14 are prepared as a composition after storage for 70 days and a light conversion layer is formed using the composition, a light conversion layer with excellent optical properties cannot be formed. It is clear that

As in the above examples, the dispersion of the present invention has excellent storage stability. Additionally, the light conversion layer formed from the dispersion of the present invention exhibits good luminescence characteristics.

The dispersion of the present invention has little change in luminescent properties and has excellent long-term storage properties. Therefore, it can be applied to various devices such as light conversion layers, color filters, wavelength conversion films, and further color display devices and liquid crystal display elements.

100: light emitting element
200: EL light source unit
1: Bottom plate
2: anode
3: Hole injection layer
4: hole transport layer
5: Light-emitting layer
6: electron transport layer
7: Electron injection layer
8: cathode
9: sealing layer
10: Filled layer
11: protective layer
12: Light conversion layer
13: Upper plate
14: EL layer
20: Pixel unit
20a: first pixel unit
20b: second pixel unit
20c: third pixel unit
21a: first light scattering particle
21b: second light scattering particle
21c: third light scattering particle
22a: first curing component
22b: second curing component
22c: third curing component
90a: first luminescent particle
90b: second luminous particle
30: light blocking part
40: Laminated structure
41: first substrate
42: second substrate
43: sealing layer
44: Wavelength conversion film
441: Light scattering particles
442: Luminous particles
701: Condenser
702: Driving transistor
703: Power line
705: Common electrode
706: signal line
707: scan line
708: switching transistor
C1: Signal line driving circuit
C2: Scan line driving circuit
C3: control circuit
PE: Pixel electrode

Claims (7)

A dispersion containing luminescent particles having a surface layer containing a structure having a siloxane bond on the surface of a semiconductor nanocrystal made of metal halide, and having a moisture content of 0.10% or more and 1.0% or less. The dispersion according to claim 1, wherein the ratio of water to the luminescent particles (water/luminescent particles) is 0.05 or more and 10.0 or less. The method of claim 1, wherein the semiconductor nanocrystal is _a compound represented by the general formula A _a M _b
A is Cs, Rb, methylammonium, formamidinium, ammonium, 2-phenylethylammonium, pyrrolidinium, piperidinium, 1-butyl-1-methylpiperidinium, tetramethylammonium, tetraethylammonium, Represents one or more cations selected from the group consisting of benzyltrimethylammonium and benzyltriethylammonium,
Wherein M represents a metal ion selected from the group consisting of Pb, Sn, Ge, Bi, Sb, Ag, In, Cu, Yb, Ti, Pd, Mn, Eu, Zr and Tb,
wherein X represents one or more halide ions selected from the group consisting of F, Cl, Br and I,
A dispersion where a represents a positive number from 1 to 7, b represents a positive number from 1 to 4, and c represents a positive number from 1 to 16. The dispersion according to claim 1, wherein the semiconductor nanocrystals have a perovskite-type crystal structure. A composition comprising the dispersion according to any one of claims 1 to 4 and a thermoplastic resin. The composition according to claim 5, wherein the thermoplastic resin is at least one selected from acrylic resin, styrene resin, cyclic olefin resin, cellulose acylate resin, and polycarbonate resin. A light conversion layer formed from the composition according to claim 5.