KR20200093999A - A quantum dot, a quantum dot light-emitting diode and a quantum dot film and a light converting resin composition comprising the quantum dot, a color filter and a light converting laminated base material manufactured by the composition and a display device comprising the same - Google Patents

Abstract

The present invention provides a quantum dot having a ligand layer on a surface, wherein the ligand layer contains a compound represented by formula 1, a quantum dot light-emitting diode including the same, a quantum dot film, a light converting resin composition, a color filter formed using the light converting resin composition, a light converting laminated base material, and a display device including the color filter and the light converting laminated base material.

Description

A quantum dot, a quantum dot light emitting diode including the same, a quantum dot film, a light conversion resin composition, a color filter formed using the light conversion resin composition, a light conversion laminated substrate and an image display device including the color filter or the light conversion laminated substrate {A QUANTUM DOT, A QUANTUM DOT LIGHT-EMITTING DIODE AND A QUANTUM DOT FILM AND A LIGHT CONVERTING RESIN COMPOSITION COMPRISING THE QUANTUM DOT, A COLOR FILTER AND A LIGHT CONVERTING LAMINATED BASE MATERIAL MANUFACTURED BY THE COMPOSITION AND A DISPLAY DEICE

The present invention includes a quantum dot, a quantum dot light emitting diode comprising the same, a quantum dot film, a light conversion resin composition, a color filter formed using the light conversion resin composition, a light conversion laminated base material and the color filter or the light conversion laminated base material It relates to an image display device.

Since quantum dots have high luminescence and a narrow emission spectrum, the emission wavelength can be controlled by a single excitation wavelength, and they have a unique characteristic of stable quantum dots for light. Many studies have been conducted for use in the same important application field.

The quantum dot is a material that is very sensitive to the state of the surface, and oxidation occurs from the surface depending on the dispersed solvent or the surrounding environment, resulting in a rapid decrease in luminous efficiency. For various applications of quantum dots, it must be dispersed in various solvents in addition to the organic solvent that was initially dispersed, or a specific functional group must be formed on the surface, and these processes damage the surface of the quantum dots and eventually lead to a decrease in luminous efficiency. There is this.

Many attempts have been made to overcome this problem, and various methods are currently being proposed. One of them is a ligand exchange method in which organic substances present on the surface of a quantum dot are substituted with molecules having a desired functional group. This method is intended to apply an organic molecule existing on the surface of the quantum dot, but is a method of substituting with a suitable organic molecule, but has a disadvantage of causing a fatal problem in luminous efficiency because it directly affects the surface of the quantum dot.

Korean Patent Publication No. 10-2018-0002716 and Korean Patent Registration No. 10-1628065 disclose quantum dots containing a ligand disposed on a surface, but have low compatibility, poor dispersibility for monomers, and stability and reliability. It is a situation where the problem that the light resistance decreases over time due to deterioration is not solved.

Republic of Korea Patent Publication No. 10-2018-0002716 Republic of Korea Registered Patent No. 10-1628065

The present invention is to improve the above-described problems of the prior art, including a compound represented by the formula (1) on the surface as a ligand layer, the surface of the quantum dot is protected, the oxidation stability is excellent, the quantum efficiency degradation is prevented, Therefore, an object of the present invention is to provide a quantum dot with improved reliability.

In addition, an object of the present invention is to provide a quantum dot film including the quantum dots, a light conversion resin composition and a quantum dot light emitting diode (Quantum Dot Light-Emitting Diode, QLED).

In addition, an object of the present invention is to provide an image display device comprising a color filter, a light conversion laminated base material and the color filter or the light conversion laminated base material formed using the light conversion resin composition.

The present invention is a quantum dot having a ligand layer on the surface,

The ligand layer provides a quantum dot comprising a compound represented by Formula 1 below.

[Formula 1]

In Chemical Formula 1,

또는

이고,A is a straight-chain or branched-chain mercaptoalkyl group having 1 to 10 carbon atoms, a straight-chain or branched chain carboxyl group having 1 to 10 carbon atoms,

or

ego,

R is a direct bond or a straight or branched chain alkylene group having 1 to 10 carbon atoms,

In the above, R ₁ is a direct bond or a straight or branched chain alkylene group having 1 to 10 carbon atoms,

R ₂ in the above is hydrogen or an alkyl group having 1 to 10 carbon atoms

* Represents a bonding hand,

n is an integer from 1 to 250.

In addition, the present invention provides a quantum dot light emitting diode, a quantum dot film and a light conversion resin composition comprising the quantum dots.

In addition, the present invention provides an image display device including a color filter, a light conversion laminated base material and the color filter or the light conversion laminated base material formed using the light conversion resin composition.

The quantum dot according to the present invention includes a compound represented by a specific chemical structure as a ligand layer, and thus the surface of the quantum dot is protected, thereby providing excellent oxidation stability and preventing quantum efficiency degradation.

Accordingly, the quantum dots can provide an effect of improving quantum efficiency and reliability, and thus can be effectively applied to various uses such as a quantum dot film, a quantum dot light emitting diode, a color filter, and a light conversion laminated substrate.

Hereinafter, the present invention will be described in detail.

The present invention provides a quantum dot having a ligand layer on its surface, wherein the ligand layer comprises a compound represented by the following Chemical Formula 1.

The quantum dots of the present invention have the effect of improving the oxidation stability by preventing the surface of the quantum dots by protecting the surface of the quantum dots by including a specific compound in the ligand layer, thus improving the luminance and reliability.

In addition, the present invention provides a quantum dot light-emitting diode (Quantum Dot Light-Emitting Diode, QLED), a quantum dot film or light conversion resin composition containing the quantum dots.

In addition, the present invention provides a color filter formed using the light conversion resin composition, a light conversion laminated base material and an image display device including the color filter or the light conversion laminated base material.

Hereinafter, the configuration of the present invention will be described in detail.

<quantum shop>

In the present invention, the quantum dots self-emission by the light source may be used to generate light in the visible and infrared regions. A quantum dot is a material having a crystal structure of several nanometers, and may be composed of hundreds to thousands of atoms. Atoms form molecules, and molecules form clusters of small molecules called clusters to form nanoparticles. Usually, these nanoparticles are called quantum dots, especially when they have semiconductor properties. If it conforms to the concept, it is not particularly limited. When an object becomes smaller than a nano size, a quantum confinement effect, which is a phenomenon in which the energy band gap of the object increases, appears, and when the quantum dot receives energy from the outside and reaches an excited state, the energy band itself It releases energy corresponding to the gap and can self-emit.

The quantum dot according to the present invention has a ligand layer on the surface, and the ligand layer is characterized by including a compound represented by the following Chemical Formula 1. Accordingly, the surface of the quantum dots is protected, oxidation stability is improved, a decrease in quantum efficiency is prevented, and reliability can be improved.

[Formula 1]

In Chemical Formula 1,

또는

이고,A is a straight-chain or branched-chain mercaptoalkyl group having 1 to 10 carbon atoms, a straight-chain or branched chain carboxyl group having 1 to 10 carbon atoms,

or

ego,

R is a direct bond or a straight or branched chain alkylene group having 1 to 10 carbon atoms,

In the above, R ₁ is a direct bond or a straight or branched chain alkylene group having 1 to 10 carbon atoms,

In the above, R ₂ is hydrogen or an alkyl group having 1 to 10 carbon atoms,

* Represents a bonding hand,

n is an integer from 1 to 250.

The compound represented by Formula 1 includes a hydroxyl group, an alkoxy group, a mercaptoalkyl group, a carboxyl group, and the like, and a hydroxyl group, an alkoxy group, a mercaptoalkyl group, and/or a carboxyl group can be bonded to the quantum dot surface. The group has superior bonding strength to the surface of the quantum dots compared to the ligand layer compounds possessed by the conventional quantum dots, thereby suppressing the quenching due to surface defects such as dangling bonds of the quantum dots and quenching due to surface oxidation, thereby improving optical properties (luminescence properties) and reliability. It has the advantage of improving.

In one embodiment of the present invention, the compound represented by Formula 1 may be a compound represented by any one of the following Formulas 1-1 to 1-5.

[Formula 1-1]

In Formula 1-1, n is an integer from 1 to 250.

[Formula 1-2]

In Formula 1-2, n is an integer from 1 to 250.

[Formula 1-3]

In Formula 1-3, n is an integer from 1 to 250.

[Formula 1-4]

In Formula 1-4, n is an integer from 1 to 250.

[Formula 1-5]

In Formula 1-5, n is an integer from 1 to 250.

In the present invention, the formulas having a range of n values among the formulas 1-1 to 1-5 are different from single molecules, and in the case of reagents having an oligomer level or higher, the n value is usually a PDI value of 1 or higher as a mixture. It does not need to be a single value, but can be specified in a specific range.

More specifically, the compounds of Chemical Formulas 1-1 to 1-5 may have the following chemical structural formula.

[Formula 1-3-1]

[Formula 1-4-1]

[Formula 1-4-2]

[Formula 1-5-1]

[Formula 1-5-2]

The compound represented by Chemical Formula 1 of the present invention is an organic ligand and may coordinately bind to the surface of the quantum dot to perform a role of stabilizing the quantum dot.

It is common for quantum dots to be prepared to have a ligand layer on the surface, and immediately after production, the ligand layer is oleic acid, lauric acid, 2-(2-methoxyethoxy)acetic acid, 2 -[2-(2-methoxyethoxy)ethoxy]acetic acid, and succinic acid mono-[2-(2-methoxy-ethoxy)-ethyl] ester. In this case, the quantum dot according to the present invention contains the compound represented by Formula 1 as a ligand layer, and the thiol group and the surface of the quantum dot have a strong bonding force, compared to that of the quantum dot due to the weaker bonding force between the quantum dot surface and non-bonding defects. For this reason, the surface protection effect may be lowered. Also, in the case of oleic acid, it is well dispersed in an unsaturated hydrocarbon solvent such as n-hexane, which is a volatile organic compound (VOC), and an aromatic solvent such as chloroform and benzene, but has poor dispersibility in a solvent such as PGMEA. . The quantum dot according to the present invention includes the compound represented by Chemical Formula 1 as a ligand layer, and exhibits an effect of improving optical properties due to excellent dispersibility in a solvent such as PGMEA.

The quantum dot is not particularly limited as long as it is a quantum dot particle that can emit light by stimulation by light or electricity. For example, II-VI semiconductor compound; III-V semiconductor compound; IV-VI semiconductor compound; A group IV element or a compound containing the same; And it may be selected from the group consisting of a combination thereof, these may be used alone or in combination of two or more.

For example, the II-VI semiconductor compound may be a binary compound selected from the group consisting of CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, and mixtures thereof; CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, selected from HgZnS, HgZnT And CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe and mixtures thereof, but are not limited thereto.

The group III-V semiconductor compound is a binary element selected from the group consisting of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, and mixtures thereof; A ternary compound selected from the group consisting of GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, and mixtures thereof; And GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, and mixtures thereof. It is not limited.

The group IV-VI semiconductor compound is a binary element selected from the group consisting of SnS, SnSe, SnTe, PbS, PbSe, PbTe, and mixtures thereof; Ternary compounds selected from the group consisting of SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe and mixtures thereof; And SnPbSSe, SnPbSeTe, SnPbSTe, and mixtures thereof, but may be one or more selected from the group consisting of tetrahydrogen compounds.

Although not limited thereto, the group IV element or a compound containing the same may be selected from the group consisting of Si, Ge and mixtures thereof; And a binary element compound selected from the group consisting of SiC, SiGe, and mixtures thereof.

Quantum dots are homogeneous single structures; Dual structures such as a core-shell structure and a gradient structure; Or it may be a mixed structure of these, and in the present invention, the quantum dot is not particularly limited as long as it can emit light by stimulation by light.

According to one embodiment, the quantum dot has a core-shell structure, the core is InP, InZnP, InGaP, CdSe, CdS, CdTe, ZnS, ZnSe, ZnTe, CdSeTe, CdZnS, CdSeS, PbSe, PbS, PbTe, AgInZnS, Contains one or more selected from the group consisting of HgS, HgSe, HgTe, GaN, GaP, GaAs, InGaN, InAs, and ZnO, and the shell is ZnS, ZnSe, ZnTe, ZnO, CdS, CdSe, CdTe, CdO, InP , InS, GaP, GaN, GaO, InZnP, InGaP, InGaN, InZnSCdSe, PbS, TiO, SrSe and may include one or more selected from the group consisting of HgSe, preferably, InP/ZnS, InP/ZnSe , InP/GaP/ZnS, InP/ZnSe/ZnS, InP/ZnSeTe/ZnS and InP/MnSe/ZnS.

In general, quantum dots may be prepared by a wet chemical process, a metal organic chemical vapor deposition (MOCVD), or a molecular beam epitaxy (MBE).

The wet chemical process is a method of growing particles by adding a precursor material to an organic solvent. When the crystal grows, the organic solvent naturally coordinates to the surface of the quantum dot crystal and acts as a dispersing agent to control the growth of the crystal. It is possible to control the size growth of quantum dot particles through an easier and cheaper process than a vapor deposition method such as epitaxy.

The quantum dot according to the present invention may be a compound (eg, oleic acid) constituting the ligand layer immediately after the preparation of the quantum dot is replaced with a compound represented by Chemical Formula 1 through a ligand exchange reaction.

For example, in the ligand exchange reaction, an organic ligand to be exchanged, that is, a compound represented by Chemical Formula 1 is added to a dispersion containing a quantum dot bound with oleic acid as a ligand layer, and this is 30 minutes at room temperature to 200°C. It can be carried out by stirring for 3 hours to obtain a quantum dot to which the compound represented by Formula 1 is bound. If necessary, the process of separating and purifying the quantum dots to which the compound of Formula 1 is bound may be further performed.

The quantum dot according to an embodiment of the present invention has the advantage that it can be produced by an organic ligand exchange method under a simple stirring treatment at room temperature as described above, so that mass production is possible.

In addition, the quantum dots according to an embodiment of the present invention can maintain a quantum efficiency of about 90% or more compared to the initial quantum efficiency not only after 7 days, but also after 15 days, so it can be stably stored for a long period of time and commercialized for various uses. .

<quantum dot light emitting diode>

The quantum dot light-emitting diode (QLED) according to the present invention may include the aforementioned quantum dots.

A quantum dot light emitting diode is an electroluminescence (EL) type device that emits light by electrically exciting quantum dots.

The quantum dot light emitting diode emits an exciton in the quantum dot light emitting layer, and electrons and holes injected from both electrodes emit light through radiative recombination of the exciton. Since it has the same operating principle as an organic light-emitting diode (OLED), it is constructed by replacing only the light-emitting layer with a quantum dot instead of an organic light-emitting material in a multi-layer device structure that uses the electron/hole injection layer and transport layer of a conventional OLED as it is. Can be.

The method for manufacturing a quantum dot light emitting diode according to the present invention is not particularly limited, and a method known in the art can be used.

For example, a method of manufacturing a quantum dot light emitting diode may be manufactured by sequentially stacking an anode, a cathode, an electron injection/transport layer, a light emitting layer, a hole transport layer, and a hole injection layer.

For another embodiment, a method of manufacturing a quantum dot light emitting diode may be manufactured by sequentially stacking a cathode, an electron injection/transport layer, a light emitting layer, a hole transport layer, a hole injection layer, and an anode. The method of manufacturing a diode may be produced by sequentially laminating an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, an electron injection and transport layer, and a cathode.

In this case, the light emitting layer may include the quantum dots described above.

<quantum dot film>

The quantum dot film according to the present invention may include the quantum dots described above.

The quantum dot film includes a polymer resin and a quantum dot dispersion layer comprising the above-described quantum dots dispersed in the polymer resin.

Examples of the polymer resin include epoxy, epoxy acrylate, lauryl acrylate, norbornene, polyethylene, polystyrene, ethylene-styrene copolymer, acrylate containing bisphenol A and bisphenol A derivatives, and fluorene derivatives Acrylate, isobornyl acrylate, polyphenylalkylsiloxane, polydiphenylsiloxane, polydialkylsiloxane, silsesquioxane, silicone fluoride, vinyl and hydride substituted silicone, etc. can be used, and these polymer resins can be used alone or It can be used by mixing two or more kinds.

The quantum dot film may further include a barrier layer on at least one surface of the quantum dot dispersion layer.

The barrier layer may have an oxygen permeability of 0.001 cm 3 /m 2 ·day·bar or less and a water permeability of 0.001 g/m 2 ·day or less, such as polyester, polycarbonate, polyolefin, cyclic olefin polymer, or polyimide. can do.

The thickness of the quantum dot dispersion layer may be 10 μm to 100 μm, and the thickness of the barrier layer may be 50 μm to 70 μm.

The method of manufacturing the quantum dot film according to the present invention is not particularly limited, and methods known in the art can be used.

For one embodiment, a method of manufacturing a quantum dot film,

a) preparing a lower transparent substrate;

b) forming a quantum dot thin film by applying a quantum dot dispersion to the lower transparent substrate; And

c) manufacturing a quantum dot film by laminating an upper transparent substrate on the quantum dot thin film.

<Light conversion resin composition>

The method for producing the light conversion resin composition of the present invention is not particularly limited, and methods known in the art can be used.

For example, the light conversion resin may include the above-described quantum dots, binder resins, photopolymerizable compounds, thermopolymerizable compounds, photopolymerization initiators, and solvents, in addition to coloring agents including pigments and dyes, scattering particles, etc. Accordingly, it may further include a configuration known in the art.

The thus prepared light conversion resin composition can be preferably used for the production of color filters and image display devices including the same.

<Color filter>

The pattern forming method for forming the color filter of the present invention can use a method known in the art.

In one embodiment, the pattern forming method,

a) applying a light conversion resin composition to the substrate;

b) a prebaking step of drying the solvent;

c) placing a photo mask on the resulting film to irradiate active light to cure the exposed portion;

d) performing a developing process of dissolving the unexposed portion using an aqueous alkali solution; And

e) drying and post-baking.

The substrate may be a glass substrate or a polymer substrate, but is not limited thereto. As the glass substrate, in particular, soda-lime glass, barium or strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, quartz, or the like can be preferably used. Further, examples of the polymer substrate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, and poly sulfone substrates.

At this time, the coating may be performed by a known wet coating method using a coating device such as a roll coater, spin coater, slit-and-spin coater, slit coater (sometimes also referred to as a die coater), inkjet, etc. to obtain a desired thickness. .

Pre-baking is performed by heating with an oven, a hot plate, or the like. At this time, the heating temperature and the heating time in the pre-baking are appropriately selected depending on the solvent used, and for example, it may be performed at a temperature of 80 to 150°C for 1 to 30 minutes.

In addition, exposure performed after pre-baking is performed by an exposure machine and exposed through a photo mask, so that only the portion corresponding to the pattern is exposed. At this time, for the light to be irradiated, for example, visible light, ultraviolet light, X-rays, and electron beams may be used.

The developing step of dissolving the unexposed portion using an aqueous alkali solution after exposure is performed for the purpose of removing the photosensitive resin composition of the unexposed portion and the desired pattern is formed. As a developing solution suitable for the development using this aqueous alkali solution, for example, an aqueous solution of a carbonate of an alkali metal or an alkaline earth metal can be used. In particular, using a less alkaline aqueous solution containing 1 to 3% by weight of carbonates such as sodium carbonate, potassium carbonate, lithium carbonate, etc., a developing device or ultrasonic cleaner is used at a temperature of 10 to 50°C, preferably 20 to 40°C. Can be done.

Post-baking is performed to increase the adhesion between the patterned film and the substrate, and may be performed through heat treatment at 80 to 250° C. for 10 to 120 minutes, for example. Post-baking, like pre-baking, can be performed using an oven, hot plate, or the like.

<Light conversion laminated base material>

The light conversion laminated base material according to the present invention includes a cured product of the light conversion resin composition. The light conversion laminated base material may include a light conversion resin composition that can be coated on a glass substrate, so that a solvent that does not correspond to a human harmful substance can be used, thereby improving worker safety and product productivity.

The photo-conversion laminating substrate may be silicon (Si), silicon oxide (SiOx), or a polymer substrate, and the polymer substrate may be polyethersulfone (PES) or polycarbonate (PC).

The photo-conversion laminated substrate may be formed by applying the photo-conversion resin composition and thermal curing.

<Image display device>

The image display apparatus according to the present invention includes the above-described color filter or light conversion laminated base material. Specifically, the image display device includes a liquid crystal display (liquid crystal display; LCD), an organic EL display (organic EL display), a liquid crystal projector, a display device for a game machine, a display device for a mobile terminal such as a mobile phone, and a display for a digital camera. And a display device such as a device or a display device for car navigation, and a color display device is particularly suitable.

The image display device may further include a configuration known to those skilled in the art in the technical field of the present invention, except that the light conversion laminated substrate is provided. That is, the present invention includes an image display device to which the light conversion laminated base material of the present invention can be applied.

The image display device including the color filter or the light conversion laminated base material according to the present invention may have excellent characteristics in color reproducibility, luminance, light resistance and reliability.

Hereinafter, the present invention will be described in more detail through examples. However, the following examples are intended to illustrate the present invention more specifically, but the scope of the present invention is not limited by the following examples.

Synthesis Example 1: InP/ZnS core-shell quantum dot synthesis

In a 3-neck flask, 0.05839 g of indium acetate, 0.12019 g of oleic acid, and 10 mL of 1-octadecene (ODE) were added. After the flask was stirred and degassed for 30 minutes at 110°C and 100 mTorr, the solution was heated to a temperature of 270°C under an inert gas until the solution became transparent.

Tris(trimethylsilyl)phosphine as a phosphorus (P) precursor was prepared at 0.025054g, placed in 0.5 mL of 1-octadecene and 0.5 mL of tri-n-octylphosphine and stirred to heat the flask to 270°C under inert gas. Was injected quickly. After reacting for 1 hour, the reaction was terminated by rapid cooling. Then, when the temperature of the flask reached 100°C, 10 mL of toluene was injected and then transferred to a 50 mL centrifuge tube. After adding 10 mL of ethanol, it was purified twice using a precipitation and redispersion method. The purified InP core nanoparticles were dispersed in 1-octadecene and stored.

In a three-necked flask, 3.669 g of zinc acetate, 20 mL of oleic acid and 20 mL of 1-octadecene were added, and after degassing for 30 minutes at 110°C and 100 mTorr while stirring, the solution was clarified under an inert gas until it became clear. After heating to a temperature of 270 °C and cooling to 60 °C to obtain a transparent zinc oleate-type zinc precursor solution.

In a three-necked flask, add 0.6412 g of sulfur (S) and 10 mL of tri-n-octylphosphine (TOP), heat to 80° C. while stirring in an inert gas atmosphere until the solution becomes clear, and then cool to room temperature TOP: An S precursor solution was obtained.

In a separate three-necked flask, the nanoparticle solution of the prepared InP core was put in advance, the temperature of the flask was adjusted to 300°C, and 0.6 mL of the pre-prepared zinc precursor solution was rapidly injected using a syringe. Thereafter, 0.3 mL of the pre-prepared sulfur precursor solution was injected into the flask at a rate of 2 mL/hr using a syringe pump. After the injection was completed, the reaction was further performed for 3 hours, and the reaction was terminated by cooling rapidly. When the temperature of the flask reached 100°C, 10 mL of toluene was injected, and then transferred to a 50 mL centrifuge tube. After adding 10 mL of ethanol, it was purified twice using a precipitation and redispersion method. The purified InP/ZnS core-shell nanoparticles were dispersed in n-chloroform and stored. The solid content was adjusted to 10%. The maximum emission wavelength was 525 nm.

Synthesis Example 2: InP/ZnSe/ZnS core-shell quantum dot synthesis

Indium acetate (Indium acetate) 0.4mmol (0.058g), palmitic acid (palmitic acid) 0.6mmol (0.15g) and 1-octadecene (octadecene) 20mL was placed in a reactor and heated to 120 ℃ under vacuum. After 1 hour, the atmosphere in the reactor was converted to nitrogen. After heating to 280° C., a mixed solution of 0.2 mmol (58 μl) of tris(trimethylsilyl)phosphine (TMS 3 P) and 1.0 mL of trioctylphosphine was rapidly injected and reacted for 0.5 minute.

Subsequently, 2.4 mmol of zinc acetate (0.448 g), 4.8 mmol of oleic acid, and 20 mL of trioctylamine were placed in a reactor and heated to 120° C. under vacuum. After 1 hour, the atmosphere in the reactor was converted to nitrogen and the reactor was heated to 280°C. 2 mL of the previously synthesized InP core solution was added, and then 4.8 mmol of selenium (Se/TOP) in trioctylphosphine was added, and the final mixture was reacted for 2 hours. Ethanol was added to the reaction solution rapidly cooled to room temperature, and the precipitate obtained by centrifugation was filtered under reduced pressure and then dried under reduced pressure to form an InP/ZnSe core-shell.

Subsequently, 2.4 mmol of zinc acetate (0.448 g), 4.8 mmol of oleic acid and 20 mL of trioctylamine were placed in a reactor and heated to 120° C. under vacuum. After 1 hour, the atmosphere in the reactor was converted to nitrogen and the reactor was heated to 280°C. 2 mL of the previously synthesized InP core solution was added, and then 4.8 mmol of sulfur (S/TOP) in trioctylphosphine was added, and the final mixture was reacted for 2 hours. Ethanol was added to the reaction solution rapidly cooled to room temperature, and the precipitate obtained by centrifugation was filtered under reduced pressure and then dried under reduced pressure to obtain quantum dots of an InP/ZnSe/ZnS core-shell structure and then dispersed in chloroform. The solid content was adjusted to 10%. The maximum emission wavelength was 520 nm.

Preparation of quantum dots according to Examples and Comparative Examples

Example 1 Ligand Substitution Reaction 1 (LE-1)

5 mL of the quantum dot solution obtained in Synthesis Example 1 was placed in a centrifuge tube, and 20 mL of ethanol was added to precipitate. The supernatant was discarded through centrifugation and 3 mL of chloroform was added to the precipitate to disperse the quantum dots, followed by reacting for 1 hour while heating to 60° C. under a Lipoamido-dPEG®8-acid (Sigma-Aldrich) nitrogen atmosphere. After precipitating quantum dots by adding 25 mL of n-hexane to the reaction material, the precipitate was separated by centrifugation, and then PGMEA was added to a solid content of 10% for dispersion. The maximum emission wavelength was 520 nm.

[Formula 1-4-1]

Example 2. Ligand Substitution Reaction 2 (LE-2)

The same procedure as in Example 1 was performed except that 1.0 g of Lipoamido-dPEG®12-acid (Sigma-Aldrich) was used instead of the ligand used in Example 1. The solid content was adjusted to 10%. The maximum emission wavelength was 520 nm.

[Formula 1-4-2]

Example 3. Ligand Substitution Reaction 3 (LE-3)

The same procedure as in Example 1 was performed except that 1.0 g of LA-PEG-COOH, 2K (Biochempeg Scientific) was used instead of the ligand used in Example 1. The solid content was adjusted to 10%. The maximum emission wavelength was 521 nm.

Example 4. Ligand Substitution Reaction 4 (LE-4)

The same procedure as in Example 1 was performed except that 1.0 g of LA-PEG-COOH, 5K (Biochempeg Scientific) was used instead of the ligand used in Example 1. The solid content was adjusted to 10%. The maximum emission wavelength was 522 nm.

Example 5 Ligand Substitution Reaction 5 (LE-5)

5 mL of the quantum dot solution obtained in Synthesis Example 2 was placed in a centrifuge tube, and 20 mL of ethanol was added to precipitate. Discard the supernatant through centrifugation, add 3 mL of chloroform to the precipitate to disperse the quantum dots, add 1.0 g of m-dPEG®8-Lipoamide (Sigma-Aldrich), add it, and heat it to 60°C under a nitrogen atmosphere for one hour. To react.

Subsequently, 25 mL of n-hexane was added to the reactant to precipitate quantum dots, followed by centrifugation to separate the precipitate, followed by dispersing by adding PGMEA to 10% solids. The maximum emission wavelength was 520 nm.

[Formula 1-3-1]

Example 6 Ligand Substitution Reaction 6 (LE-6)

The same procedure as in Example 5 was performed, except that 1.0 g of mPEG-LA,2K (Biochempeg Scientific) was used instead of the ligand used in Example 5. The solid content was adjusted to 10%. The maximum emission wavelength was 521 nm.

Example 7 Ligand Substitution Reaction 7 (LE-7)

The same procedure as in Example 5 was performed except that 1.0 g of mPEG-LA,5K (Biochempeg Scientific) was used instead of the ligand used in Example 5. The solid content was adjusted to 10%. The maximum emission wavelength was 522 nm.

Example 8. Ligand substitution reaction 8 (LE-8)

The same procedure as in Example 5 was performed, except that SH-PEG-LA,1K (Biochempeg Scientific) was used instead of the ligand used in Example 5. The solid content was adjusted to 10%. The maximum emission wavelength was 520 nm.

Example 9 Ligand Substitution Reaction 9 (LE-9)

The same procedure as in Example 5 was performed, except that SH-PEG-LA,2K (Biochempeg Scientific) was used instead of the ligand used in Example 5. The solid content was adjusted to 10%. The maximum emission wavelength was 521 nm.

Example 10. Ligand Substitution Reaction 10 (LE-10)

It was carried out in the same manner as in Example 5, except that Lipoamido-PEG2-alcohol (BroadPharm Co.) was used instead of the ligand used in Example 5. The solid content was adjusted to 10%. The maximum emission wavelength was 521 nm.

[Formula 1-5-1]

Example 11. Ligand Substitution Reaction 11 (LE-11)

The procedure was carried out in the same manner as in Example 5, except that Lipoamido-PEG3-alcohol (BroadPharm Co.) was used instead of the ligand used in Example 5. The solid content was adjusted to 10%. The maximum emission wavelength was 521 nm.

[Formula 1-5-2]

Comparative Example 1: Preparation of quantum dots of InP/ZnS core alone without ligand exchange reaction

The quantum dots of Synthesis Example 1 in which oleic acid was bonded to the surface were dispersed in chloroform at a concentration of 10%.

Comparative Example 2: InP/ZnSe/ZnS core-shell quantum dot preparation without ligand exchange reaction

The quantum dots of Synthesis Example 2 in which oleic acid was bonded to the surface were dispersed in chloroform at a concentration of 10%.

Comparative Example 3. Ligand Substitution Reaction 10 (LE-10)

The same procedure as in Example 5 was performed except that Thioctic acid (Sigma Aldrich Co.) was used instead of the ligand used in Example 5. The solid content was adjusted to 10%. The maximum emission wavelength was 525 nm.

[Formula 2-1]

Comparative Example 4. Ligand Substitution Reaction 11 (LE-11)

The same procedure as in Example 5 was performed, except that LA-PEG-NH2,2K (Biochempeg Scientific) was used instead of the ligand used in Example 5. The solid content was adjusted to 10%. The maximum emission wavelength was 525 nm.

Test example

(1) Quantum efficiency

The quantum efficiency (QY%) at the initial stage of manufacturing the quantum dot dispersions of Examples 1 to 11 and Comparative Examples 1 to 4 and the absolute quantum efficiency (QY%) after 15 days of standing at room temperature were measured using QE-2100 (Otsuka Co.). Did.

Since quantum efficiency is reduced by quantum dot surface oxidation, it is possible to confirm oxidation stability by measuring a decrease in quantum efficiency. The measurement results are shown in Table 1 below. When the ΔQY% value is 15 or less, it has excellent quantum efficiency.

[Table 1]

(2) Light resistance

The quantum dot dispersions of Examples 1 to 11 and Comparative Examples 1 to 4 were measured using QE-2100 (Otsuka Co., Ltd.) after the initial maximum absorption wavelength (λmax) and leaving the blue LED light source at room temperature for 7 days at room temperature. . When QY(%) is 15 or less, it has excellent light resistance.

When the surface of the quantum dot is oxidized with a defect that is not protected by a ligand, the quantum efficiency decreases. Reliability can be confirmed by measuring the amount of reduction in absolute quantum efficiency. The measurement results for this are shown in Table 2 below.

[Table 2]

As shown in Tables 1 and 2, the quantum dots of Examples 1 to 11 having the ligands of Formula 1 according to the present invention have a ΔQY% value, that is, a change in quantum efficiency of less than or equal to 15 in the initial stage and after standing, and the oxidation stability It was confirmed that it has excellent reliability by having excellent values of light resistance and less than 15 accordingly.

On the other hand, in the case of the quantum dots of Comparative Examples 1 to 4 not containing the ligand of the present invention, the amount of change in quantum efficiency increased more than 4 times compared to the quantum dots of the present invention, and the light resistance also has a change amount of 3.9 times or more, oxidation stability and light resistance It was confirmed that this dropping was very low, and thus the reliability was significantly reduced.

Claims (13)

As a quantum dot having a ligand layer on the surface,
Quantum dots, characterized in that the ligand layer comprises a compound represented by the formula (1):
[Formula 1]

In Chemical Formula 1,
A is a straight-chain or branched-chain mercaptoalkyl group having 1 to 10 carbon atoms, a straight-chain or branched chain carboxyl group having 1 to 10 carbon atoms,

or

ego,
R is a direct bond or a straight or branched chain alkylene group having 1 to 10 carbon atoms,
In the above, R ₁ is a direct bond or a straight or branched chain alkylene group having 1 to 10 carbon atoms, and R ₂ is hydrogen or a straight or branched chain alkyl group having 1 to 10 carbon atoms.
* Represents a bonding hand,
n is an integer from 1 to 250.
The method according to claim 1,
In Chemical Formula 1, A is a straight chain mercaptoalkyl group having 1 to 10 carbon atoms, a straight chain carboxyl group having 1 to 10 carbon atoms,

or

ego,
In the above, R is a direct bond or a straight chain alkylene group having 1 to 10 carbon atoms,
In the above, R ₁ is a direct bond or a straight chain alkylene group having 1 to 10 carbon atoms,
R ₂ in the above is hydrogen or a straight chain alkyl group having 1 to 10 carbon atoms, quantum dots.
The method according to claim 1,
The ligand layer includes at least one member selected from the group consisting of compounds represented by the following Chemical Formulas 1-1 to 1-5, quantum dots:
[Formula 1-1]

In Formula 1-1, n is an integer from 1 to 250.
[Formula 1-2]

In Formula 1-2, n is an integer from 1 to 250.
[Formula 1-3]

In Formula 1-3, n is an integer from 1 to 250.
[Formula 1-4]

In Formula 1-4, n is an integer from 1 to 250.
[Formula 1-5]

In Formula 1-5, n is an integer from 1 to 250.
The method according to claim 1,
The ligand layer includes oleic aicd, lauric acid, 2-(2-methoxyethoxy)acetic acid, 2-[2-(2-methoxyethoxy)ethoxy]acetic acid and A quantum dot further comprising at least one member selected from the group consisting of succinic acid mono-[2-(2-methoxy-ethoxy)-ethyl] ester.
The method according to claim 1,
The quantum dot has a core-shell structure,
The core is InP, InZnP, InGaP, CdSe, CdS, CdTe, ZnS, ZnSe, ZnTe, CdSeTe, CdZnS, CdSeS, PbSe, PbS, PbTe, AgInZnS, HgS, HgSe, HgTe, GaN, GaP, GaP And one or more selected from the group consisting of ZnO,
The shell is selected from the group consisting of ZnS, ZnSe, ZnTe, ZnO, CdS, CdSe, CdTe, CdO, InP, InS, GaP, GaN, GaO, InZnP, InGaP, InGaN, InZnSCdSe, PbS, TiO, SrSe and HgSe A quantum dot comprising at least one.
The method according to claim 1,
The quantum dot is characterized in that it comprises one or more selected from the group consisting of InP/ZnS, InP/ZnSe, InP/GaP/ZnS, InP/ZnSe/ZnS, InP/ZnSeTe/ZnS and InP/MnSe/ZnS. Quantum dots.
Quantum dot light-emitting diode (QLED) comprising a quantum dot according to any one of claims 1 to 6.
Quantum dot film comprising a quantum dot according to any one of claims 1 to 6.
A light conversion resin composition comprising the quantum dots according to claim 1.
A color filter formed using the light conversion resin composition according to claim 9.
A light conversion laminated base material formed using the light conversion resin composition according to claim 9.
An image display device comprising the color filter according to claim 10.
An image display device comprising the light conversion laminated base according to claim 11.