KR102732873B1 - Light Conversion Ink Composition, Color Filter and Display Device - Google Patents

Abstract

The present invention provides a photoconversion ink composition comprising a quantum dot and a curable monomer, wherein the quantum dot has a ligand layer comprising a polyethylene glycol-based ligand having a specific structure on its surface, and the curable monomer comprises a bifunctional (meth)acrylate having a specific structure, a color filter formed using the same, and an image display device having the color filter. The photoconversion ink composition according to the present invention has excellent optical properties and dispersibility of quantum dots even without a solvent, and can implement low viscosity. Therefore, the photoconversion ink composition according to the present invention can be effectively used to manufacture a color filter by an inkjet printing method.

Description

{Light Conversion Ink Composition, Color Filter and Display Device}

The present invention relates to a photoconversion ink composition, a color filter, and an image display device, and more specifically, to a photoconversion ink composition having excellent optical properties and dispersibility of quantum dots and capable of implementing low viscosity even without a solvent, a color filter formed using the same, and an image display device equipped with the color filter.

A color filter is a thin film-type optical component that extracts three colors, red, green, and blue, from white light and enables it to be divided into fine pixel units, with each pixel having a size of tens to hundreds of micrometers. Such a color filter has a structure in which a black matrix layer formed in a set pattern on a transparent substrate to block light at the boundary between each pixel, and a pixel unit in which three primary colors of multiple colors (usually red (R), green (G), and blue (B)) are arranged in a set order to form each pixel are sequentially laminated.

Recently, a pigment dispersion method using a pigment-dispersed photosensitive resin has been applied as one of the methods for implementing color filters. However, when light irradiated from a light source passes through a color filter, some of the light is absorbed by the color filter, which reduces light efficiency, and also, due to the characteristics of the pigment included in the color filter, there is a problem that color reproduction is reduced.

In particular, as color filters are used in various fields including various image display devices, not only excellent pattern characteristics but also high color reproducibility, high brightness, high contrast ratio, and other performances are required. In order to solve these problems, a method for manufacturing a color filter using a self-luminous photosensitive resin composition containing quantum dots has been proposed. For example, Korean Patent Publication No. 10-2009-0036373 discloses that by replacing an existing color filter with a light-emitting layer composed of a quantum dot fluorescent substance, light-emitting efficiency can be improved, thereby improving the display quality of a display device.

The photolithography method using a photosensitive resin composition containing such quantum dots is a method of forming a color filter through coating, exposure, development, and curing. Although it is excellent in terms of the precision and reproducibility of the color filter, the coating, exposure, development, and curing processes are required for each color to form pixels, which increases the manufacturing process, time, and cost, and the number of control factors between processes increases, making it difficult to manage the yield.

To solve these problems, the inkjet method has been proposed. The inkjet method is a technology that uses an inkjet head to spray liquid ink to designated locations to implement an image in which each ink is colored. Since multiple colors including red, green, and blue can be colored at once, the manufacturing process, time, and cost can be greatly reduced.

Recently, as high color reproducibility (color density compared to NTSC) is required for monitors, TVs, etc., it is necessary to improve the luminescence brightness of quantum dots. In order to improve the luminescence brightness, there is a method of increasing the film thickness. However, there is a limit to increasing the film thickness with an ink composition containing quantum dots and a solvent. Accordingly, a solvent-free ink composition containing quantum dots that does not contain a solvent is required.

However, when quantum dots are manufactured as a non-solvent composition, uniform dispersion is difficult, which may cause agglomeration of quantum dots, which may result in a decrease in the optical properties of the quantum dots or an increase in viscosity, which may result in poor jetting properties.

Therefore, there is an urgent need for the development of an ink composition that has excellent optical properties and dispersibility of quantum dots and can achieve low viscosity without a solvent.

Republic of Korea Patent Publication No. 10-2009-0036373

One object of the present invention is to provide a photoconversion ink composition having excellent optical properties and dispersibility of quantum dots and capable of implementing low viscosity without a solvent.

Another object of the present invention is to provide a photoconversion pixel comprising a cured product of the photoconversion ink composition.

Another object of the present invention is to provide a color filter including the photoconversion pixel.

Another object of the present invention is to provide an image display device having the color filter.

On the one hand, the present invention provides a photoconversion ink composition comprising a quantum dot and a curable monomer, wherein the quantum dot has a ligand layer comprising at least one of the compounds represented by the following chemical formulas 1a to 1e on a surface thereof, and the curable monomer comprises a compound represented by the following chemical formula 2.

[Chemical formula 1a]

[Chemical formula 1b]

[Chemical formula 1c]

[chemical formula 1d]

[Chemical formula 1e]

[Chemical formula 2]

In the above formula,

R' and R'' are each independently a hydrogen atom; a carboxyl group; a phenyl group; or a C ₁ -C ₂₀ alkyl group substituted or unsubstituted with a thiol group,

R' and R" are not simultaneously a hydrogen atom; a phenyl group; or an unsubstituted C ₁ -C ₂₀ alkyl group,

R ^a , R ^b and R ^c are each independently a C ₁ -C ₂₂ alkyl group or a C ₄ -C ₂₂ alkenyl group,

R ^d is a C ₁ -C ₂₂ alkylene group, a C ₃ -C ₈ cycloalkylene group, or a C ₆ -C ₁₄ arylene group,

A and B are each independently absent, or are an alkylene group of C ₁ -C ₂₂ , O, NR or S,

R is hydrogen or an alkyl group of C ₁ -C ₂₂ ,

X is a carboxyl group, a phosphate group, a thiol group, an amine group, a tetrazole group, an imidazole group, a pyridine group, or a lipoamido group,

n is an integer from 1 to 20,

p, q, t and u are each independently an integer from 1 to 100,

r is an integer from 1 to 10,

R ¹ is a C ₁ -C ₂₀ alkylene group, a phenylene group or a C ₃ -C ₁₀ cycloalkylene group,

R ² is hydrogen or a methyl group,

m is an integer from 1 to 15.

In one embodiment of the present invention, the quantum dots may be non-cadmium quantum dots.

In one embodiment of the present invention, the quantum dot has a core-shell structure including a core and a shell covering the core, wherein the core includes at least one selected from the group consisting of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb, and the shell may include at least one selected from the group consisting of ZnSe, ZnS, and ZnTe.

The photoconversion ink composition according to one embodiment of the present invention may additionally include scattering particles.

In one embodiment of the present invention, the scattering particles may include at least one selected from the group consisting of Al ₂ O ₃ , SiO ₂ , ZnO, ZrO ₂ , BaTiO ₃ , TiO ₂ , Ta ₂ O ₅ , Ti ₃ O ₅ , ITO, IZO, ATO, ZnO-Al, Nb ₂ O ₃ , SnO and MgO.

In one embodiment of the present invention, the scattering particles may be TiO ₂ .

The photoconversion ink composition according to one embodiment of the present invention may additionally contain a photopolymerization initiator.

The photoconversion ink composition according to one embodiment of the present invention may not contain a solvent.

On the other hand, the present invention provides a photoconversion pixel comprising a cured product of the photoconversion ink composition.

On the other hand, the present invention provides a color filter including the photoconversion pixel.

On the other hand, the present invention provides an image display device characterized by being equipped with the color filter.

The photoconversion ink composition according to the present invention does not include a solvent, contains quantum dots having a polyethylene glycol-based ligand of a specific structure on the surface as a colorant, and contains a bifunctional (meth)acrylate of a specific structure having excellent compatibility with the polyethylene glycol-based ligand as a curable monomer, so that the optical properties and dispersibility of the quantum dots are excellent and low viscosity can be implemented. Therefore, the photoconversion ink composition according to the present invention can be effectively used to manufacture a color filter by an inkjet printing method.

Hereinafter, the present invention will be described in more detail.

In the present invention, when it is said that a certain member is located "on" another member, this includes not only a case where a certain member is in contact with another member, but also a case where another member exists between the two members.

When it is said that a part of the present invention "includes" a certain component, this does not exclude other components, unless otherwise specifically stated, but rather means that other components may be included.

One embodiment of the present invention relates to a photoconversion ink composition comprising a quantum dot (A) and a curable monomer (B), wherein the quantum dot (A) has a ligand layer comprising a polyethylene glycol-based ligand having a specific structure on a surface, and the curable monomer (B) comprises a bifunctional (meth)acrylate having a specific structure.

Quantum Dot (A)

In one embodiment of the present invention, the quantum dot has a ligand layer comprising at least one of the compounds represented by the following chemical formulas 1a to 1e on its surface.

[Chemical formula 1a]

[Chemical formula 1b]

[Chemical formula 1c]

[chemical formula 1d]

[Chemical formula 1e]

In the above formula,

R' and R'' are each independently a hydrogen atom; a carboxyl group; a phenyl group; or a C ₁ -C ₂₀ alkyl group substituted or unsubstituted with a thiol group,

R' and R" are not simultaneously a hydrogen atom; a phenyl group; or an unsubstituted C ₁ -C ₂₀ alkyl group,

R ^a , R ^b and R ^c are each independently a C ₁ -C ₂₂ alkyl group or a C ₄ -C ₂₂ alkenyl group,

R ^d is a C ₁ -C ₂₂ alkylene group, a C ₃ -C ₈ cycloalkylene group, or a C ₆ -C ₁₄ arylene group,

A and B are each independently absent, or are an alkylene group of C ₁ -C ₂₂ , O, NR or S,

R is hydrogen or an alkyl group of C ₁ -C ₂₂ ,

X is a carboxyl group, a phosphate group, a thiol group, an amine group, a tetrazole group, an imidazole group, a pyridine group, or a lipoamido group,

n is an integer from 1 to 20,

p, q, t and u are each independently an integer from 1 to 100,

r is an integer from 1 to 10.

The C ₁ -C ₂₀ alkyl group used in the present specification means a straight-chain or branched monovalent hydrocarbon having 1 to 20 carbon atoms, and includes, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methyl-butyl, 1-ethyl-butyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, n-heptyl, 1-methylhexyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, n-decyl, n-undecyl, etc. It is not limited to this.

The C ₁ -C ₂₂ alkyl group used in the present specification means a straight-chain or branched monovalent hydrocarbon having 1 to 22 carbon atoms, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methyl-butyl, 1-ethyl-butyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, n-heptyl, 1-methylhexyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, n-decyl, n-undecyl, Includes, but is not limited to, n-docosanil.

As used herein, the C ₄ -C ₂₂ alkenyl group means a straight-chain or branched monovalent unsaturated hydrocarbon having 4 to 22 carbon atoms and having at least one carbon-carbon double bond, and examples thereof include, but are not limited to, butenylene, pentenylene, hexenylene, heptenylene, octenylene, nonenylene, decenylene, undecenylene, dodecenylene, tridecenylene, tetradecenylene, pentadecenylene, hexadecenylene, heptadecenylene, octadecenylene, and the like.

The above C ₁ -C ₂₀ alkyl group, C ₁ -C ₂₂ alkyl group and C ₄ -C ₂₂ alkenyl group may have one or more hydrogens substituted with a C ₁ -C ₆ alkyl group, a C ₂ -C ₆ alkenyl group, a C ₂ -C ₆ alkynyl group, a C ₃ -C ₁₀ cycloalkyl group, a C ₃ -C ₁₀ heterocycloalkyl group, a C ₃ -C ₁₀ heterocycloalkyloxy group, a C ₁ -C ₆ haloalkyl group, a C ₁ -C ₆ alkoxy group, a C ₁ -C ₆ thioalkoxy group, an aryl group, an acyl group, hydroxy, thio, halogen, amino, alkoxycarbonyl, carboxy, carbamoyl, cyano, nitro, etc.

The compound represented by the chemical formula 1a of the present invention may be a compound in which R' is a C ₁ -C ₂₀ alkyl group substituted or unsubstituted with a thiol group and R'' is a carboxyl group, in terms of the optical properties and dispersibility of quantum dots and the implementation of low viscosity.

In one embodiment of the present invention, specific examples of the compound represented by the chemical formula 1a include, but are not limited to, 2-(2-methoxyethoxy)acetic acid (WAKO), 2-[2-(2-methoxyethoxy)ethoxy]acetic acid (WAKO), {2-[2-(carboxymethoxy)ethoxy]ethoxy}acetic acid (WAKO), 2-[2-(benzyloxy)ethoxy]acetic acid, (2-(carboxymethoxy)ethoxy)acetic acid (WAKO), (2-butoxyethoxy)acetic acid (WAKO), carboxy-EG6-undecanethiool, and the like.

The compound represented by the chemical formula 1b of the present invention may be a compound in which R ^a is a C ₁ -C ₂₂ alkyl group or a C ₄ -C ₂₀ alkenyl group, and p is an integer from 1 to 50, in terms of implementing optical properties and dispersibility of quantum dots and low viscosity. In particular, when p in the chemical formula 1b exceeds the above range, it may affect the viscosity of the photoconversion ink composition.

The compound represented by the above chemical formula 1b has a thiol group, and the thiol group can bind to the surface of the quantum dot. In the case of the thiol group, compared to ligand layer compounds that typical quantum dots have, such as carboxylic acid, the bonding strength with the surface of the quantum dot is excellent, and thus, quenching due to surface defects such as dangling bonds of the quantum dot and quenching due to surface oxidation are suppressed, thereby improving the optical characteristics (luminescence characteristics) and reliability.

In one embodiment of the present invention, the compound represented by the chemical formula 1b may be at least one compound selected from compounds represented by the following chemical formulas 1-1 to 1-6 in terms of optical properties and dispersibility of quantum dots and low viscosity implementation.

[Chemical Formula 1-1]

[Chemical Formula 1-2]

[Chemical Formula 1-3]

[Chemical Formula 1-4]

[Chemical Formula 1-5]

[Chemical Formula 1-6]

The compound represented by the chemical formula 1c of the present invention may be a compound in which q is an integer from 1 to 50 and r is an integer from 1 to 8, in terms of the optical properties and dispersibility of quantum dots and the implementation of low viscosity. In particular, when q and r in the chemical formula 1c exceed the above range, the viscosity of the photoconversion ink composition may be affected.

The compound represented by the above chemical formula 1c has a thiol group, and the thiol group can bind to the surface of the quantum dot. In the case of the thiol group, compared to ligand layer compounds that typical quantum dots have, such as carboxylic acid, the bonding strength with the surface of the quantum dot is excellent, and thus, quenching due to surface defects such as dangling bonds of the quantum dot and quenching due to surface oxidation are suppressed, thereby improving the optical characteristics (luminescence characteristics) and reliability.

In one embodiment of the present invention, the compound represented by the chemical formula 1c may be at least one compound selected from compounds represented by the following chemical formulas 1-7 to 1-12 in terms of optical properties and dispersibility of quantum dots and low viscosity implementation.

[Chemical Formula 1-7]

[Chemical Formula 1-8]

[Chemical Formula 1-9]

[Chemical Formula 1-10]

[Chemical Formula 1-11]

[Chemical Formula 1-12]

The compound represented by the chemical formula 1d of the present invention may be a compound in which R ^b is a C ₁ -C ₂₂ alkyl group or a C ₄ -C ₂₀ alkenyl group, and t is an integer from 1 to 50, in terms of implementing optical properties and dispersibility of quantum dots and low viscosity. In particular, when t in the chemical formula 1d exceeds the above range, it may affect the viscosity of the photoconversion ink composition.

The compound represented by the above chemical formula 1d has an amine group, and the amine group can bind to the surface of the quantum dot. In the case of the amine group, compared to ligand layer compounds that typical quantum dots have, such as carboxylic acid, the bonding strength with the surface of the quantum dot is excellent, and thus, quenching due to surface defects such as dangling bonds of the quantum dot and quenching due to surface oxidation are suppressed, thereby improving the optical characteristics (luminescence characteristics) and reliability.

In one embodiment of the present invention, the compound represented by the chemical formula 1d may be at least one compound selected from compounds represented by the following chemical formulas 1-13 to 1-18 in terms of optical properties and dispersibility of quantum dots and low viscosity implementation.

[Chemical Formula 1-13]

[Chemical Formula 1-14]

[Chemical Formula 1-15]

[Chemical Formula 1-16]

[Chemical Formula 1-17]

[Chemical Formula 1-18]

The compound represented by the chemical formula 1e of the present invention may be a compound in which R ^c is a C ₁ -C ₂₂ alkyl group or a C ₄ -C ₂₂ alkenyl group, R ^d is a C ₁ -C ₂₂ alkylene group, a C ₃ -C ₈ cycloalkylene group or a C ₆ -C ₁₄ arylene group, A and B are each independently absent, or a C ₁ -C ₂₂ alkylene group, O, NR or S, R is hydrogen or a C ₁ -C ₂₂ alkyl group, X is a carboxyl group, a phosphoric acid group, a thiol group, an amine group, a tetrazole group, an imidazole group, a pyridine group or a lipoamido group, and u is an integer from 1 to 50, in terms of implementing optical properties and dispersibility of quantum dots and low viscosity. In particular, when u in the chemical formula 1e exceeds the above range, the viscosity of the photoconversion ink composition may be affected.

In one embodiment of the present invention, the compound represented by the chemical formula 1e may be at least one compound selected from compounds represented by the following chemical formulas 1-19 to 1-25 in terms of optical properties and dispersibility of quantum dots and low viscosity implementation.

[Chemical Formula 1-19]

[Chemical Formula 1-20]

[Chemical Formula 1-21]

[Chemical Formula 1-22]

[Chemical Formula 1-23]

[Chemical Formula 1-24]

[Chemical Formula 1-25]

The compounds represented by the chemical formulas 1a to 1e of the present invention can serve to stabilize quantum dots by being coordinately bonded to the surface of quantum dots as organic ligands.

Conventionally manufactured quantum dots generally have a ligand layer on their surface, and the ligand layer may be formed of oleic acid, lauric acid, or the like immediately after manufacturing. In this case, when the quantum dot according to the present invention includes a compound represented by the chemical formulae 1a to 1e as a ligand layer, the surface protection effect may be reduced due to non-bonding defects on the surface of the quantum dot due to a weaker bonding force with the quantum dot compared to when the quantum dot includes the compound represented by the chemical formulae 1a to 1e as a ligand layer. In addition, in the case of oleic acid, it is well dispersed in aliphatic hydrocarbon solvents such as n-hexane, which is a highly volatile organic compound (VOC), and aromatic hydrocarbon solvents such as benzene, but has poor dispersibility in solvents such as propylene glycol methyl ether acetate (PGMEA). The quantum dot according to the present invention includes a compound represented by the chemical formulae 1a to 1e as a ligand layer, and thus exhibits an effect of improving optical characteristics due to excellent dispersibility in solvents such as PGMEA.

In addition, the quantum dot can exhibit good dispersion characteristics with only the curable monomer described below without a solvent by including one or more polyethylene glycol-based ligands among the compounds represented by the chemical formulas 1a to 1e.

The compounds represented by the above chemical formulas 1a to 1e may cover a surface area of 5% or more of the total surface area of the quantum dot.

At this time, the content of the compounds represented by the chemical formulas 1a to 1e may be 0.1 to 10 moles per 1 mole of the quantum dot.

The ligand layer including the compounds represented by the chemical formulae 1a to 1e may have a thickness of 0.1 nm to 2 nm, for example, a thickness of 0.5 nm to 1.5 nm.

In one embodiment of the present invention, the quantum dot may refer to a semiconductor material of nano size. Atoms form molecules, and molecules form a collection of small molecules called clusters to form nanoparticles. When these nanoparticles have semiconductor properties, they are called quantum dots. When the quantum dot receives energy from the outside and reaches an excited state, it emits energy according to the energy band gap corresponding to the quantum dot itself. For example, the photoconversion ink composition of the present invention can convert incident blue light into green light and red light by including such quantum dots.

In one embodiment of the present invention, the quantum dots may be non-cadmium quantum dots.

The above-mentioned non-cadmium quantum dots are not particularly limited as long as they are quantum dot particles that can emit light when stimulated by light. For example, they may be selected from the group consisting of II-VI group semiconductor compounds; III-V group semiconductor compounds; IV-VI group semiconductor compounds; IV group elements or compounds containing them; and combinations thereof, and these may be used singly or in combination of two or more.

Specifically, the II-VI group semiconductor compound may be selected from, but is not limited to, a binary compound selected from the group consisting of ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, and mixtures thereof; a ternary compound selected from the group consisting of ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, HgZnS, HgZnSe, HgZnTe, and mixtures thereof; and a quaternary compound selected from the group consisting of HgZnSeS, HgZnSeTe, HgZnSTe, and mixtures thereof.

The above III-V group semiconductor compound may be selected from the group consisting of binary compounds selected from the group consisting of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, and mixtures thereof; ternary compounds 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 quaternary compounds selected from the group consisting of GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, and mixtures thereof, but is not limited thereto.

The above IV-VI group semiconductor compound may be at least one selected from the group consisting of a binary compound selected from the group consisting of SnS, SnSe, SnTe, PbS, PbSe, PbTe, and mixtures thereof; a ternary compound selected from the group consisting of SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, and mixtures thereof; and a quaternary compound selected from the group consisting of SnPbSSe, SnPbSeTe, SnPbSTe, and mixtures thereof, but is not limited thereto.

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

The quantum dot may have a homogeneous single structure; a dual structure such as a core-shell or gradient structure; or a mixed structure thereof. Preferably, the quantum dot may have a core-shell structure including a core and a shell covering the core.

Specifically, in the above core-shell dual structure, the materials forming each core and shell can be formed of different semiconductor compounds as mentioned above. For example, the core may include at least one selected from the group consisting of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb, and the shell may include at least one selected from the group consisting of ZnSe, ZnS, and ZnTe, but is not limited thereto.

For example, quantum dots with core-shell structures include InP/ZnS, InP/ZnSe, InP/GaP/ZnS, InP/ZnSe/ZnS, InP/ZnSeTe/ZnS, and InP/MnSe/ZnS.

The above quantum dots can be synthesized by, but are not limited to, a wet chemical process, a metal organic chemical vapor deposition (MOCVD) process, or a molecular beam epitaxy (MBE) process, but preferably, synthesizing them by a wet chemical process can obtain quantum dots with better optical properties.

The above 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 is naturally coordinated to the surface of the quantum dot crystal and acts as a dispersant to control the growth of the crystal. Therefore, the growth of nanoparticles can be controlled through a process that is easier and cheaper than a vapor deposition method such as an organometallic chemical vapor deposition process or molecular beam epitaxy. Therefore, it is preferable to manufacture the quantum dots using the above wet chemical process.

When producing quantum dots by a wet chemical process, organic ligands are used to prevent aggregation of quantum dots and to control the particle size of quantum dots to the nano level. Oleic acid can generally be used as such organic ligands.

In one embodiment of the present invention, the oleic acid used in the process of manufacturing the quantum dot is replaced by a ligand exchange method with one or more polyethylene glycol compounds represented by the chemical formulas 1a to 1e.

The above ligand exchange can be performed by adding an organic ligand to be exchanged, that is, one or more polyethylene glycol compounds among the compounds represented by chemical formulas 1a to 1e, to a dispersion containing quantum dots having an original organic ligand, that is, oleic acid, and stirring the mixture at room temperature to 200° C. for 30 minutes to 3 hours to obtain quantum dots to which one or more polyethylene glycol compounds among the compounds represented by chemical formulas 1a to 1e are bound. If necessary, a process of separating and purifying the quantum dots to which one or more polyethylene glycol compounds among the compounds represented by chemical formulas 1a to 1e are bound can be additionally performed.

The quantum dots may be included in an amount of 1 to 60 wt%, preferably 5 to 50 wt%, based on 100 wt% of the total light conversion ink composition. When the quantum dots are included within the above range, there are advantages of excellent luminescence efficiency and excellent reliability of the coating layer. When the quantum dots are included in an amount less than the above range, the light conversion efficiency of green light and red light may be low, and when the quantum dots are included in an amount exceeding the above range, the emission of blue light may be relatively reduced, resulting in a problem of poor color reproducibility.

Curable monomer (B)

In one embodiment of the present invention, the curable monomer (B) comprises a compound represented by the following chemical formula 2.

[Chemical formula 2]

In the above formula,

R ¹ is a C ₁ -C ₂₀ alkylene group, a phenylene group, or a C ₃ -C ₁₀ cycloalkylene group,

R ² is hydrogen or a methyl group,

m is an integer from 1 to 15.

As used herein, the C ₁ -C ₂₀ alkylene group means a straight-chain or branched divalent hydrocarbon having 1 to 20 carbon atoms, and examples thereof include, but are not limited to, methylene, ethylene, n-propylene, isopropylene, n-butylene, isobutylene, n-pentylene, n-hexylene, n-heptylene, n-octylene, n-nonylene, and the like.

As used herein, the C ₃ -C ₁₀ cycloalkylene group means a simple or fused ring divalent hydrocarbon having 3 to 10 carbon atoms, and examples thereof include, but are not limited to, cyclopropylene, cyclobutylene, cyclopentylene, and cyclohexylene.

The above C ₁ -C ₂₀ alkylene group, phenylene group and C ₃ -C ₁₀ cycloalkylene group may have one or more hydrogen atoms substituted with a C ₁ -C ₆ alkyl group, a C ₂ -C ₆ alkenyl group, a C ₂ -C ₆ alkynyl group, a C ₃ -C ₁₀ cycloalkyl group, a C ₃ -C ₁₀ heterocycloalkyl group, a C ₃ -C ₁₀ heterocycloalkyloxy group, a C ₁ -C ₆ haloalkyl group, a C ₁ -C ₆ alkoxy group, a C ₁ -C ₆ thioalkoxy group, an aryl group, an acyl group, hydroxy, thio, halogen, amino, alkoxycarbonyl, carboxy, carbamoyl, cyano, nitro, etc.

In one embodiment of the present invention, R ¹ may be a C ₁ -C ₂₀ alkylene group, preferably a C ₁ -C ₁₂ alkylene group, as described above. When R ¹ is a C ₁ -C ₂₀ alkylene group, the dispersibility of scattering particles is excellent even without a solvent, so that the jetting property is improved, and the film hardness and surface properties can be improved.

In one embodiment of the present invention, m is an integer from 1 to 15 as described above, preferably an integer from 1 to 5. When m exceeds the above range, the viscosity may be high and the dispersibility may be poor.

Specific examples of the compound represented by the above chemical formula 2 include 1,6-hexanediol diacrylate, 1,9-bisacryloyloxynonane, tripropylene glycol diacrylate, etc.

The compound represented by the above chemical formula 2 has excellent compatibility with the polyethylene glycol-based ligands represented by the above chemical formulas 1a to 1e, thereby improving the dispersibility of quantum dots, thereby enabling the implementation of a low-viscosity photoconversion ink composition with excellent optical properties even without a solvent. Accordingly, the photoconversion ink composition according to the present invention can be effectively used to manufacture a color filter by an inkjet printing method.

The photoconversion ink composition of the present invention may further include a polymerizable compound commonly used in the relevant field, in addition to the polymerizable compound represented by the above chemical formula 2, within the scope that does not deviate from the purpose of the present invention. Examples thereof include monofunctional monomers, difunctional monomers, and other multifunctional monomers, and among these, difunctional monomers are preferably used.

The type of the above monofunctional monomer is not particularly limited, and examples thereof include nonylphenylcarbitol acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-ethylhexylcarbitol acrylate, 2-hydroxyethyl acrylate, N-vinylpyrrolidone, etc.

The type of the above bifunctional monomer is not particularly limited, and examples thereof include bis(acryloyloxyethyl)ether of bisphenol A.

The type of the above-mentioned multifunctional monomer is not particularly limited, and examples thereof include trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, ethoxylated dipentaerythritol hexa(meth)acrylate, propoxylated dipentaerythritol hexa(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and the like.

The above-mentioned curable monomer (B) may be included in an amount of 20 to 90 wt%, preferably 30 to 80 wt%, based on 100 wt% of the total weight of the photoconversion ink composition. When the above-mentioned curable monomer is included within the above range, there is a desirable advantage in terms of the strength or smoothness of the pixel portion. When the above-mentioned curable monomer is included in an amount less than the above range, the strength of the pixel portion may be somewhat reduced, and when the above-mentioned curable monomer is included in an amount exceeding the above range, the smoothness may be somewhat reduced, and therefore it is preferable that the above-mentioned range be included.

Scattered particles (C)

The photoconversion ink composition according to one embodiment of the present invention may additionally include scattering particles (C).

The above scattering particles serve to increase the overall light efficiency by increasing the path of light emitted from the quantum dot.

As the above scattering particles, conventional inorganic materials can be used, and preferably, metal oxides can be used.

The above metal oxide may be an oxide including one metal selected from the group consisting of Li, Be, B, Na, Mg, Al, Si, K, Ca, Sc, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, Rb, Sr, Y, Mo, Cs, Ba, La, Hf, W, Tl, Pb, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Ti, Sb, Sn, Zr, Nb, Ce, Ta, In, and combinations thereof, but is not limited thereto.

Specifically, one selected from the group consisting of Al ₂ O ₃ , SiO ₂ , ZnO, ZrO ₂ , BaTiO ₃ , TiO ₂ , Ta ₂ O ₅ , Ti ₃ O ₅ , ITO, IZO, ATO, ZnO-Al, Nb ₂ O ₃ , SnO, MgO and combinations thereof is possible. If necessary, a material surface-treated with a compound having an unsaturated bond such as acrylate can also be used.

The scattering particles may have an average particle size of 50 to 1000 nm, preferably 100 to 500 nm, and more preferably 150 to 300 nm. If the particle size is too small, sufficient scattering effect of light emitted from the quantum dots cannot be expected, and conversely, if it is too large, it may sink into the composition or a light conversion layer surface of uniform quality may not be obtained. Therefore, it is appropriately adjusted and used within the above range.

In the present invention, the average particle diameter may be a number-average particle diameter, and may be obtained from an image observed by, for example, a field emission scanning electron microscope (FE-SEM) or a transmission electron microscope (TEM). Specifically, several samples may be extracted from an observation image of an FE-SEM or TEM, and the diameters of these samples may be measured and obtained as an arithmetic average.

The scattering particles may be included in an amount of 0.5 to 20 wt%, preferably 1 to 15 wt%, based on 100 wt% of the total light conversion ink composition. When the scattering particles are included within the above range, the effect of increasing luminescence intensity can be maximized, which is preferable. When the scattering particles are included in an amount less than the above range, it may be somewhat difficult to secure the desired luminescence intensity, and when the particles are included in an amount exceeding the above range, the transmittance of blue irradiation light may be reduced, which may cause problems in luminescence efficiency.

Photopolymerization initiator (D)

The photoconversion ink composition according to one embodiment of the present invention may additionally contain a photopolymerization initiator (D).

In one embodiment of the present invention, the photopolymerization initiator (D) can be used without particular limitation as long as it can polymerize the curable monomer. In particular, from the viewpoints of polymerization characteristics, initiation efficiency, absorption wavelength, availability, price, etc., it is preferable that the photopolymerization initiator (D) use at least one compound selected from the group consisting of acetophenone compounds, benzophenone compounds, triazine compounds, biimidazole compounds, oxime compounds, and thioxanthone compounds.

The photopolymerization initiator (D) may be included in an amount of 0.01 to 20 wt%, preferably 0.5 to 15 wt%, based on 100 wt% of the total photoconversion ink composition. When the photopolymerization initiator is included within the above range, the photoconversion ink composition becomes highly sensitive, thus shortening the exposure time, thereby improving productivity, which is preferable. In addition, there is an advantage in that the strength of the pixel portion formed using the photoconversion ink composition according to the present invention and the smoothness on the surface of the pixel portion are improved.

The above photopolymerization initiator (D) may further include a photopolymerization initiation assistant (d1) in order to improve the sensitivity of the photoconversion ink composition according to the present invention. When the above photopolymerization initiation assistant is included, the sensitivity is further increased, thereby providing the advantage of improved productivity.

The above photopolymerization initiation assistant (d1) may preferably be one or more compounds selected from the group consisting of, for example, amine compounds, carboxylic acid compounds, and organic sulfur compounds having a thiol group, but is not limited thereto.

The above photopolymerization initiation auxiliary agent (d1) can be appropriately added and used within a range that does not impair the effects of the present invention.

Additive (E)

The photoconversion ink composition according to one embodiment of the present invention may further include, in addition to the above-described components, additives such as a surfactant or adhesion promoter to improve film flatness or adhesion.

When the photoconversion ink composition according to the present invention includes the surfactant, there is an advantage in that the film flatness can be improved. For example, the surfactant may be a fluorinated surfactant such as BM-1000, BM-1100 (BM Chemie), Prolide FC-135/FC-170C/FC-430 (Sumitomo 3M Co., Ltd.), SH-28PA/-190/-8400/SZ-6032 (Toray Silicone Co., Ltd.), etc., but is not limited thereto.

The above adhesion accelerator may be added to increase adhesion to a substrate, and may include, but is not limited to, a silane coupling agent having a reactive substituent selected from the group consisting of a carboxyl group, a methacryloyl group, an isocyanate group, an epoxy group, and combinations thereof.

In addition, the photoconversion ink composition according to the present invention may further include additives such as an antioxidant, an ultraviolet absorber, and an anti-coagulant within a range that does not impede the effects of the present invention, and the additives may be appropriately added and used by those skilled in the art within a range that does not impede the effects of the present invention.

The above additive may be used in an amount of 0.05 to 10 wt%, specifically 0.1 to 10 wt%, and more specifically 0.1 to 5 wt%, relative to 100 wt% of the total photoconversion ink composition, but is not limited thereto.

The photoconversion ink composition according to one embodiment of the present invention substantially does not contain a solvent, and even if it does contain one, it contains no more than 2 wt% based on 100 wt% of the total photoconversion ink composition. The photoconversion ink composition according to one embodiment of the present invention is a solvent-free type that does not contain a solvent, but has excellent optical properties and dispersibility of quantum dots and can realize low viscosity.

In addition, the photoconversion ink composition according to one embodiment of the present invention substantially does not contain a resin component, and even if it does contain one, it is contained within 0.5 wt% with respect to 100 wt% of the entire photoconversion ink composition. The photoconversion ink composition according to one embodiment of the present invention can implement low viscosity by not containing a resin component, and thus has excellent nozzle jetting characteristics of the ink.

One embodiment of the present invention relates to a photoconversion pixel comprising a cured product of the photoconversion ink composition described above.

In addition, one embodiment of the present invention relates to a color filter including the above-described photoconversion pixel.

A method for forming a pattern of a photoconversion ink composition according to the present invention comprises a step of applying the above-described photoconversion ink composition to a predetermined area by inkjet method and a step of curing the applied photoconversion ink composition.

First, the photoconversion ink composition of the present invention is injected into an inkjet injector and printed on a predetermined area of a substrate.

The above substrate is not limited, and examples thereof include flat-surfaced substrates such as a glass substrate, a silicon substrate, a polycarbonate substrate, a polyester substrate, an aromatic polyamide substrate, a polyamideimide substrate, a polyimide substrate, an Al substrate, and a GaAs substrate. These substrates can be pretreated by a chemical treatment using a silane coupling agent or the like, a plasma treatment, an ion plating treatment, a sputtering treatment, a gas phase reaction treatment, or a vacuum deposition treatment. When a silicon substrate or the like is used as the substrate, a charge-coupled device (CCD), a thin film transistor (TFT), or the like can be formed on the surface of the silicon substrate or the like. In addition, a barrier matrix may be formed.

In order to form an appropriate phase on a substrate by being ejected from a piezo inkjet head, which is an example of an inkjet injector, the properties such as viscosity, fluidity, and quantum dot particles must be balanced with those of the inkjet head. The piezo inkjet head used in the present invention is not limited, but ejects ink having a droplet size of about 10 to 100 pL, preferably about 20 to 40 pL.

The viscosity of the photoconversion ink composition of the present invention is suitably controlled in the range of about 3 to 30 cP, and more preferably in the range of 7 to 20 cP.

A color filter according to one embodiment of the present invention includes a colored pattern layer formed by the pattern forming method. That is, the color filter is characterized by including a colored pattern layer formed by applying the above-described photoconversion ink composition on a substrate in a predetermined pattern and then curing it. Since the configuration and manufacturing method of the color filter are well known in the art, a detailed description thereof will be omitted.

One embodiment of the present invention relates to an image display device equipped with the color filter described above.

The color filter of the present invention can be applied to various image display devices such as conventional liquid crystal displays (LCDs), electroluminescence displays (ELs), plasma display devices (PDPs), field emission displays (FEDs), and organic light emitting diodes (OLEDs).

The image display device of the present invention includes a configuration known in the art, except that it has the color filter described above.

Hereinafter, the present invention will be described in more detail by examples, comparative examples, and experimental examples. These examples, comparative examples, and experimental examples are only for explaining the present invention, and it is obvious to those skilled in the art that the scope of the present invention is not limited thereto.

Synthesis Example 1: Synthesis of Ligand-Substituted Quantum Dots (A1)

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

2.4 mmol (0.448 g) of zinc acetate, 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 inside the reactor was changed to nitrogen, and the reactor was heated to 280°C. 2 mL of the previously synthesized InP core solution was added, followed by 4.8 mmol of selenium (Se/TOP) in trioctylphosphine, and the final mixture was reacted for 2 hours. Ethanol was added to the reaction solution, which was quickly cooled to room temperature, and the precipitate obtained by centrifugation was filtered under reduced pressure and dried under reduced pressure to form an InP/ZnSe core-shell.

Then, 2.4 mmol (0.448 g) of zinc acetate, 4.8 mmol of oleic acid, and 20 mL of trioctylamine were placed in a reactor, and the reactor was heated to 120°C under vacuum. After 1 hour, the atmosphere inside the reactor was changed to nitrogen, and the reactor was heated to 280°C. 2 mL of the previously synthesized InP/ZnSe core-shell solution was added, followed by 4.8 mmol of sulfur (S/TOP) in trioctylphosphine, and the final mixture was reacted for 2 hours. Ethanol was added to the reaction solution, which was quickly cooled to room temperature, and the resulting precipitate was centrifuged, filtered under reduced pressure, and dried under reduced pressure to disperse InP/ZnSe/ZnS core-shell structured quantum dots in chloroform.

The maximum emission peak of the photoluminescence spectrum of the obtained nano quantum dots is 535 nm. 5 mL of the quantum dot solution was placed in a centrifuge tube and 20 mL of ethanol was added to precipitate. The supernatant was discarded after centrifugation, and 2 mL of chloroform was added to the precipitate to disperse the quantum dots. Then, 0.50 g of (2-butoxyethoxy)acetic acid was added and the mixture was reacted for one hour while heating at 60°C under a nitrogen atmosphere.

Next, 25 mL of n-hexane was added to the reaction mixture to precipitate quantum dots, and centrifugation was performed to obtain a precipitate.

Synthesis Example 2: Synthesis of Ligand-Substituted Quantum Dots (A2)

Indium acetate (0.4 mmol) (0.058 g), palmitic acid (0.6 mmol) and 1-octadecene (20 mL) were placed in a reactor and heated to 120°C under vacuum. After 1 hour, the atmosphere inside the reactor was changed 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 after 5 minutes of reaction, the reaction solution was quickly cooled to room temperature. The maximum absorption wavelength was 560 to 590 nm.

2.4 mmol (0.448 g) of zinc acetate, 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 inside the reactor was changed to nitrogen, and the reactor was heated to 280°C. 2 mL of the previously synthesized InP core solution was added, followed by 4.8 mmol of selenium (Se/TOP) in trioctylphosphine, and the final mixture was reacted for 2 hours and then cooled to room temperature to form an InP/ZnSe core-shell.

Then, 2.4 mmol (0.448 g) of zinc acetate, 4.8 mmol of oleic acid, and 20 mL of trioctylamine were placed in a reactor, and the reactor was heated to 120°C under vacuum. After 1 hour, the atmosphere inside the reactor was changed to nitrogen, and the reactor was heated to 280°C. 2 mL of the previously synthesized InP/ZnSe core-shell solution was added, followed by 4.8 mmol of sulfur (S/TOP) in trioctylphosphine, and the final mixture was reacted for 2 hours. Ethanol was added to the reaction solution, which was quickly cooled to room temperature, and the resulting precipitate was centrifuged, filtered under reduced pressure, and dried under reduced pressure to obtain InP/ZnSe/ZnS core-shell structured quantum dots, which were then dispersed in chloroform.

The maximum emission peak of the photoluminescence spectrum of the obtained nano quantum dots is 635 nm. 5 mL of the synthesized quantum dot solution was placed in a centrifuge tube and 20 mL of ethanol was added to precipitate. The supernatant was discarded after centrifugation, and 2 mL of chloroform was added to the precipitate to disperse the quantum dots. Then, 0.65 g of carboxy-EG6-undecanthiol was added and reacted at 60°C for one hour under a nitrogen atmosphere.

Next, 25 mL of n-hexane was added to the reaction mixture to precipitate quantum dots, and centrifugation was performed to discard the supernatant and obtain a precipitate.

Synthesis Example 3: Synthesis of Ligand-Substituted Quantum Dots (A3)

Indium acetate (0.4 mmol (0.058 g), palmitic acid (0.6 mmol (0.15 g), and 1-octadecene (20 mL)) were placed in a reactor and heated to 120°C under vacuum. After 1 hour, the atmosphere inside the reactor was changed 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 minutes.

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

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

5 mL of the synthesized quantum dot solution was placed in a centrifuge tube and 20 mL of ethanol was added to precipitate. The supernatant was discarded after centrifugation, and 3 mL of chloroform was added to the precipitate to disperse the quantum dots. Then, 1.00 g of mPEG5-SH (FutureChem) represented by the following chemical formula 1-1 was added and reacted for one hour while heating at 60°C under a nitrogen atmosphere.

[Chemical Formula 1-1]

Next, 25 mL of n-hexane was added to the reaction mixture to precipitate quantum dots, and centrifugation was performed to discard the supernatant and obtain a precipitate.

Synthesis Example 4: Synthesis of Ligand-Substituted Quantum Dots (A4)

The same procedure as in Synthesis Example 3 was followed, except that mPEG ₇ -SH (FutureChem) represented by the following chemical formula 1-2 was used instead of the ligand used in Synthesis Example 3.

[Chemical Formula 1-2]

Synthesis Example 5: Synthesis of Ligand-Substituted Quantum Dots (A5)

The same procedure as in Synthesis Example 3 was followed, except that a compound represented by the following chemical formula 1-3 was used instead of the ligand used in Synthesis Example 3.

[Chemical Formula 1-3]

Synthesis Example 6: Synthesis of Ligand-Substituted Quantum Dots (A6)

The same procedure as in Synthesis Example 3 was followed, except that a compound represented by the following chemical formula 1-4 was used instead of the ligand used in Synthesis Example 3.

[Chemical Formula 1-4]

Synthesis Example 7: Synthesis of Ligand-Substituted Quantum Dots (A7)

The same procedure as in Synthesis Example 3 was followed, except that a compound represented by the following chemical formula 1-5 was used instead of the ligand used in Synthesis Example 3.

[Chemical Formula 1-5]

Synthesis Example 8: Synthesis of Ligand-Substituted Quantum Dots (A8)

The same procedure as in Synthesis Example 3 was followed, except that a compound represented by the following chemical formula 1-6 was used instead of the ligand used in Synthesis Example 3.

[Chemical Formula 1-6]

Synthesis Example 9: Synthesis of Ligand-Substituted Quantum Dots (A9)

The same procedure as in Synthesis Example 3 was followed, except that 3.00 g of the compound represented by the following chemical formula 1-7 was used instead of 1.00 g of the ligand used in Synthesis Example 3.

[Chemical Formula 1-7]

Synthesis Example 10: Synthesis of Ligand-Substituted Quantum Dots (A10)

The same procedure as in Synthesis Example 3 was followed, except that 3.00 g of the compound represented by the following chemical formula 1-8 was used instead of 1.00 g of the ligand used in Synthesis Example 3.

[Chemical Formula 1-8]

Synthesis Example 11: Synthesis of Ligand-Substituted Quantum Dots (A11)

The same procedure as in Synthesis Example 3 was followed, except that 3.00 g of the compound represented by the following chemical formula 1-9 was used instead of 1.00 g of the ligand used in Synthesis Example 3.

[Chemical Formula 1-9]

Synthesis Example 12: Synthesis of Ligand-Substituted Quantum Dots (A12)

The same procedure as in Synthesis Example 3 was followed, except that 3.00 g of the compound represented by the following chemical formula 1-10 was used instead of 1.00 g of the ligand used in Synthesis Example 3.

[Chemical Formula 1-10]

Synthesis Example 13: Synthesis of Ligand-Substituted Quantum Dots (A13)

The same procedure as in Synthesis Example 3 was followed, except that 3.00 g of the compound represented by the following chemical formula 1-11 was used instead of 1.00 g of the ligand used in Synthesis Example 3.

[Chemical Formula 1-11]

Synthesis Example 14: Synthesis of Ligand-Substituted Quantum Dots (A14)

The same procedure as in Synthesis Example 3 was followed, except that 3.00 g of the compound represented by the following chemical formula 1-12 was used instead of 1.00 g of the ligand used in Synthesis Example 3.

[Chemical Formula 1-12]

Synthesis Example 15: Synthesis of Ligand-Substituted Quantum Dots (A15)

The same procedure as in Synthesis Example 3 was followed, except that 3.00 g of the compound represented by the following chemical formula 1-13 was used instead of 1.00 g of the ligand used in Synthesis Example 3.

[Chemical Formula 1-13]

Synthesis Example 16: Synthesis of Ligand-Substituted Quantum Dots (A16)

The same procedure as in Synthesis Example 3 was followed, except that 3.00 g of the compound represented by the following chemical formula 1-14 was used instead of 1.00 g of the ligand used in Synthesis Example 3.

[Chemical Formula 1-14]

Synthesis Example 17: Synthesis of Ligand-Substituted Quantum Dots (A17)

The same procedure as in Synthesis Example 3 was followed, except that 3.00 g of the compound represented by the following chemical formula 1-15 was used instead of 1.00 g of the ligand used in Synthesis Example 3.

[Chemical Formula 1-15]

Synthesis Example 18: Synthesis of Ligand-Substituted Quantum Dots (A18)

The same procedure as in Synthesis Example 3 was followed, except that 3.00 g of the compound represented by the following chemical formula 1-16 was used instead of 1.00 g of the ligand used in Synthesis Example 3.

[Chemical Formula 1-16]

Synthesis Example 19: Synthesis of Ligand-Substituted Quantum Dot (A19)

The same procedure as in Synthesis Example 3 was followed, except that 3.00 g of the compound represented by the following chemical formula 1-17 was used instead of 1.00 g of the ligand used in Synthesis Example 3.

[Chemical Formula 1-17]

Synthesis Example 20: Synthesis of Ligand-Substituted Quantum Dots (A20)

The same procedure as in Synthesis Example 3 was followed, except that 3.00 g of the compound represented by the following chemical formula 1-18 was used instead of 1.00 g of the ligand used in Synthesis Example 3.

[Chemical Formula 1-18]

Comparative Synthesis Example 1: Synthesis of Ligand-Free Quantum Dots (A21)

Indium acetate (0.058 g) 0.4 mmol (0.058 g), palmitic acid (0.15 g) and 1-octadecene (20 mL) were placed in a reactor and heated to 120°C under vacuum. After 1 hour, the atmosphere inside the reactor was changed 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 the reaction solution was rapidly cooled to room temperature after 5 minutes of reaction. The maximum absorption wavelength was 560 to 590 nm.

2.4 mmol (0.448 g) of zinc acetate, 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 inside the reactor was changed to nitrogen, and the reactor was heated to 280°C. 2 mL of the previously synthesized InP core solution was added, followed by 4.8 mmol of selenium (Se/TOP) in trioctylphosphine, and the final mixture was reacted for 2 hours and then cooled to room temperature to form an InP/ZnSe core-shell.

Then, 2.4 mmol (0.448 g) of zinc acetate, 4.8 mmol of oleic acid, and 20 mL of trioctylamine were placed in a reactor, and the reactor was heated to 120°C under vacuum. After 1 hour, the atmosphere inside the reactor was changed to nitrogen, and the reactor was heated to 280°C. 2 mL of the previously synthesized InP/ZnSe core-shell solution was added, followed by 4.8 mmol of sulfur (S/TOP) in trioctylphosphine, and the final mixture was reacted for 2 hours. Ethanol was added to the reaction solution, which was quickly cooled to room temperature, and the precipitate obtained by centrifugation was filtered under reduced pressure and dried under reduced pressure to obtain InP/ZnSe/ZnS core-shell structured quantum dots.

Comparative Synthesis Example 2: Synthesis of Ligand-Free Quantum Dots (A22)

Indium acetate (0.4 mmol (0.058 g), palmitic acid (0.6 mmol (0.15 g), and 1-octadecene (20 mL)) were placed in a reactor and heated to 120°C under vacuum. After 1 hour, the atmosphere inside the reactor was changed 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 minutes.

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

Then, 2.4 mmol (0.448 g) of zinc acetate, 4.8 mmol of oleic acid, and 20 mL of trioctylamine were placed in a reactor, and the reactor was heated to 120°C under vacuum. After 1 hour, the atmosphere inside the reactor was changed to nitrogen, and the reactor was heated to 280°C. 2 mL of the previously synthesized InP/ZnSe core-shell solution was added, followed by 4.8 mmol of sulfur (S/TOP) in trioctylphosphine, and the final mixture was reacted for 2 hours. Ethanol was added to the reaction solution, which was quickly cooled to room temperature, and the precipitate obtained by centrifugation was filtered under reduced pressure and dried under reduced pressure to obtain InP/ZnSe/ZnS core-shell structured quantum dots.

Comparative Synthesis Example 3: Synthesis of Ligand-Substituted Quantum Dots (A23)

The same procedure as in Synthesis Example 3 was followed, except that a compound represented by the following chemical formula a (1-dodecanethiol) was used instead of the ligand used in Synthesis Example 3.

[chemical formula a]

CH ₃ (CH ₂ ) ₁₀ CH ₂ SH

Comparative Synthesis Example 4: Synthesis of Ligand-Substituted Quantum Dots (A24)

The same procedure as in Synthesis Example 3 was followed, except that a compound represented by the following chemical formula b was used instead of the ligand used in Synthesis Example 3.

[chemical formula b]

H ₂ NCH ₂ (CH ₂ ) ₉ CH ₂ NH ₂

Manufacturing Example 1: Manufacturing of scattering particle dispersion (C1)

70.0 parts by weight of TiO ₂ (CR-63, Ishihara) having a particle size of 210 nm as a scattering particle, 4.0 parts by weight of DISPERBYK-2001 (manufactured by BYK) as a dispersant, and 26 parts by weight of 1,6-hexanediol diacrylate as a solvent were mixed and dispersed using a bead mill for 12 hours to prepare a scattering particle dispersion (C1).

Examples and Comparative Examples: Preparation of Photoconversion Ink Compositions

A photoconversion ink composition was prepared by mixing each component according to the compositions in Tables 1 to 4 below (weight %).

Example 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Quantum Dot A1 28.2 28.2 28.2 A2 29.2 29.2 29.2 A3 28.2 28.2 28.2 A4 28.2 A5 28.2 A6 28.2 A7 28.2 A8 28.2 Curable Monomer B1 61.0 60.0 61.0 61.0 61.0 61.0 61.0 61.0 B2 61.0 60.0 61.0 B3 61.0 60.0 61.0 B4 B5 B6 Scatter particle C1 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 Photopolymerization initiator D1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 Additives E1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1

Example 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Quantum Dot A9 28.2 28.2 28.2 A10 28.2 A11 28.2 A12 28.2 A13 28.2 A14 28.2 A15 28.2 28.2 28.2 A16 28.2 A17 28.2 A18 28.2 A19 28.2 A20 28.2 Curable Monomer B1 61.0 61.0 61.0 61.0 61.0 61.0 61.0 61.0 61.0 61.0 61.0 61.0 B2 61.0 61.0 B3 61.0 61.0 B4 B5 B6 Scatter particle C1 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 Photopolymerization initiator D1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 Additives E1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1

Comparative example 1 2 3 4 5 6 7 8 9 10 11 12 Quantum Dot A1 28.2 28.2 28.2 A3 28.2 28.2 28.2 A9 28.2 28.2 28.2 A15 28.2 28.2 28.2 Curable Monomer B1 B2 B3 B4 61.0 61.0 61.0 61.0 B5 61.0 61.0 61.0 61.0 B6 61.0 61.0 61.0 61.0 Scatter particle C1 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 Photopolymerization initiator D1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 Additives E1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1

Comparative example 13 14 15 16 17 18 19 20 21 22 23 24 Quantum Dot A21 28.9 28.9 28.9 A22 28.2 28.2 28.2 A23 28.2 28.2 28.2 A24 28.2 28.2 28.2 Curable Monomer B1 60.3 61.0 61.0 61.0 B2 60.3 61.0 61.0 61.0 B3 60.3 61.0 61.0 61.0 B4 B5 B6 Scatter particle C1 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 8.6 Photopolymerization initiator D1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 Additives E1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1

A1 to A24: Quantum dots manufactured in Synthesis Examples 1 to 24

B1: 1,6-Hexanediol diacrylate (Sigma-Aldrich)

B2: 1,9-Bisacryloyloxynonane (TCIA)

B3: Tripropylene glycol diacrylate (Sigma-Aldrich)

B4: Trimethylolpropane triacrylate (A-TMPT, Shin-Nakamura Chemical Co., Ltd.)

B5: Ethoxylated pentaerythritol tetraacrylate (ATM-4E, Shin-Nakamura Chemical Co., Ltd.)

B6: Dipentaerythritol hexaacrylate (A-9550, Shin-Nakamura Chemical Co., Ltd.)

C1: Scatter particle dispersion prepared in Manufacturing Example 1

D1: Irgacure OXE-01 (BASF)

E1: SH8400 (Dow Corning Toray Silicone)

Experimental example:

Using the photoconversion ink compositions manufactured in the above examples and comparative examples, a photoconversion coating layer was manufactured as follows, and the film thickness, brightness, dispersibility, and viscosity at this time were measured by the following methods, and the results are shown in Tables 5 to 6 below.

< Manufacturing of photoconversion coating layer >

Each of the photoconversion ink compositions manufactured in the examples and comparative examples was applied onto a 5 cm × 5 cm glass substrate by inkjet, and then irradiated at 1000 mJ/cm2 using a 1 kW high-pressure mercury lamp containing all of the g, h, and i lines as an ultraviolet light source, and then heated in a heating oven at 180°C for 30 minutes to manufacture a photoconversion coating layer.

(1) Film thickness

The film thickness of the photoconversion coating layer manufactured above was measured using a film thickness measuring device (Dektak 6M, Vecco).

(2) Brightness

The photoconversion coating layer manufactured above was placed on top of a blue light source (XLamp XR-E LED, Royal blue 450, Cree), and the brightness was measured when irradiated with blue light using a brightness meter (CAS140CT Spectrometer, Instrument systems).

(3) Dispersibility

In the process of manufacturing the above photoconversion ink composition, the liquid sample before adding scattering particles was visually inspected and evaluated according to the following evaluation criteria.

<Evaluation criteria>

○: Transparent state

×: cloudy state

(4) Viscosity

The viscosity of the above photoconversion ink composition was measured using an R-type viscometer (VISCOMETER MODEL RE120L SYSTEM, manufactured by Toki Sangyo Co., Ltd.) at a rotation speed of 20 rpm and a temperature of 30°C.

Evaluation Results Film thickness (㎛) Luminance (lx) Dispersive Viscosity (mPa·s) Example 1 10 1208 ○ 8.9 Example 2 10 1144 ○ 11.1 Example 3 10 1131 ○ 10.3 Example 4 10 1099 ○ 9.5 Example 5 10 1040 ○ 11.8 Example 6 10 1186 ○ 11.0 Example 7 10 1211 ○ 8.1 Example 8 10 1220 ○ 10.9 Example 9 10 1209 ○ 10.3 Example 10 10 1227 ○ 9.4 Example 11 10 1205 ○ 9.2 Example 12 10 1214 ○ 9.8 Example 13 10 1208 ○ 9.5 Example 14 10 1210 ○ 9.5 Example 15 10 1238 ○ 9.5 Example 16 10 1225 ○ 11.6 Example 17 10 1216 ○ 10.7 Example 18 10 1204 ○ 10.2 Example 19 10 1199 ○ 9.7 Example 20 10 1165 ○ 9.7 Example 21 10 1168 ○ 9.8 Example 22 10 1221 ○ 9.6 Example 23 10 1198 ○ 9.4 Example 24 10 1187 ○ 11.5 Example 25 10 1175 ○ 10.5 Example 26 10 1198 ○ 9.5 Example 27 10 1211 ○ 9.2 Example 28 10 1176 ○ 8.9 Example 29 10 1213 ○ 9.3 Example 30 10 1108 ○ 9.3

Evaluation Results Film thickness (㎛) Luminance (lx) Dispersive Viscosity (mPa·s) Comparative Example 1 10 446 × Immeasurable Comparative Example 2 10 332 × Immeasurable Comparative Example 3 10 459 × Immeasurable Comparative Example 4 10 397 × Immeasurable Comparative Example 5 10 421 × Immeasurable Comparative Example 6 10 419 × Immeasurable Comparative Example 7 10 317 × Immeasurable Comparative Example 8 10 407 × Immeasurable Comparative Example 9 10 322 × Immeasurable Comparative Example 10 10 312 × Immeasurable Comparative Example 11 10 352 × Immeasurable Comparative Example 12 10 329 × Immeasurable Comparative Example 13 10 687 × 75.2 Comparative Example 14 10 448 × Immeasurable Comparative Example 15 10 387 × Immeasurable Comparative Example 16 10 691 × 61.1 Comparative Example 17 10 445 × Immeasurable Comparative Example 18 10 384 × Immeasurable Comparative Example 19 10 512 × 46.1 Comparative Example 20 10 476 × Immeasurable Comparative Example 21 10 611 × Immeasurable Comparative Example 22 10 412 × 71.9 Comparative Example 23 10 371 × Immeasurable Comparative Example 24 10 386 × Immeasurable

As shown in Tables 5 and 6 above, it was confirmed that the photoconversion ink compositions of Examples 1 to 30 including quantum dots having polyethylene glycol-based ligands according to the present invention and a difunctional (meth)acrylate having a specific structure as a curable monomer have excellent optical properties and dispersibility of quantum dots and can implement low viscosity. On the other hand, the photoconversion ink compositions of Comparative Examples 1 to 12 not including a difunctional (meth)acrylate having a specific structure as a curable monomer and Comparative Examples 12 to 24 including quantum dots not having a polyethylene glycol-based ligand according to the present invention had low brightness and poor dispersibility, showing turbid liquid samples and having viscosity that was too high to be measured with the relevant equipment.

As described above, specific parts of the present invention have been described in detail. It is obvious to those skilled in the art that these specific descriptions are merely preferred implementation examples and that the scope of the present invention is not limited thereto. Those skilled in the art will be able to make various applications and modifications within the scope of the present invention based on the above contents.

Accordingly, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims (11)

Containing quantum dots and curable monomers,
The quantum dot has a ligand layer comprising at least one of the compounds represented by the following chemical formulas 1a to 1e on its surface,
The above curable monomer is a photoconversion ink composition comprising a compound represented by the following chemical formula 2,
A photoconversion ink composition comprising a solvent in an amount of 2 wt% or less based on 100 wt% of the total photoconversion ink composition:
[Chemical formula 1a]

[Chemical formula 1b]

[Chemical formula 1c]

[chemical formula 1d]

[Chemical formula 1e]

[Chemical formula 2]

In the above formula,
R' and R'' are each independently a hydrogen atom; a carboxyl group; a phenyl group; or a C ₁ -C ₂₀ alkyl group substituted or unsubstituted with a thiol group,
R' and R" are not simultaneously a hydrogen atom; a phenyl group; or an unsubstituted C ₁ -C ₂₀ alkyl group,
R ^a , R ^b and R ^c are each independently a C ₁ -C ₂₂ alkyl group or a C ₄ -C ₂₂ alkenyl group,
R ^d is a C ₁ -C ₂₂ alkylene group, a C ₃ -C ₈ cycloalkylene group, or a C ₆ -C ₁₄ arylene group,
A and B are each independently absent, or are an alkylene group of C ₁ -C ₂₂ , O, NR or S,
R is hydrogen or an alkyl group of C ₁ -C ₂₂ ,
X is a carboxyl group, a phosphate group, a thiol group, an amine group, a tetrazole group, an imidazole group, a pyridine group, or a lipoamido group,
n is an integer from 1 to 20,
p, q, t and u are each independently an integer from 1 to 100,
r is an integer from 1 to 10,
R ¹ is a C ₁ -C ₂₀ alkylene group, a phenylene group or a C ₃ -C ₁₀ cycloalkylene group,
R ² is hydrogen or a methyl group,
m is an integer from 1 to 15. A photoconversion ink composition in claim 1, wherein the quantum dot is a non-cadmium quantum dot. In the second paragraph, the quantum dot has a core-shell structure including a core and a shell covering the core,
The above core comprises at least one selected from the group consisting of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb,
A photoconversion ink composition wherein the shell comprises at least one selected from the group consisting of ZnSe, ZnS and ZnTe. A photoconversion ink composition further comprising scattering particles in claim 1. In claim 4, a photoconversion ink composition comprising at least one selected from the group consisting of Al ₂ O ₃ , SiO ₂ , ZnO, ZrO ₂ , BaTiO ₃ , TiO ₂ , Ta ₂ O ₅ , Ti ₃ O ₅ , ITO, IZO, ATO, ZnO-Al, Nb ₂ O ₃ , SnO and MgO. In claim 5, the light conversion ink composition wherein the scattering particles are TiO ₂ . A photoconversion ink composition further comprising a photopolymerization initiator in claim 1. A photoconversion ink composition characterized in that it does not contain a solvent in the first claim. A photoconversion pixel comprising a cured product of a photoconversion ink composition according to any one of claims 1 to 8. A color filter comprising a photoconversion pixel according to claim 9. An image display device characterized by having a color filter according to Article 10.