JP7482809B2 - Quantum dot dispersion and curable composition containing the same - Google Patents

Description

The present invention relates to a quantum dot dispersion and a curable composition containing the same, and more particularly to a quantum dot dispersion that has excellent light resistance of quantum dots and can improve the hardness of a coating film when applied to the coating film, and a curable composition containing the same.

In recent years, one method for creating color filters is the pigment dispersion method, which uses a pigment-dispersed photosensitive resin. However, this type of pigment dispersion method has problems in that the light efficiency is reduced because part of the light emitted from the light source is absorbed by the color filter as it passes through the color filter, and color reproduction is reduced due to the characteristics of the pigment contained in the color filter.

A color filter using a quantum dot photosensitive resin composition has been proposed as a solution to these problems. For example, Korean Patent Publication No. 2009-0036373 discloses that by replacing existing color filters with a light-emitting layer made of quantum dot phosphors, the light-emitting efficiency can be improved and the display quality of the display device can be improved.

When quantum dots are used as the luminescent material of a color filter in this way, the luminescence waveform can be narrowed, and high color reproducibility that cannot be realized with pigments is achieved, with excellent brightness characteristics. However, image display devices equipped with quantum dot color filters use blue light as a light source, and there is a problem in that the blue light used at this time reduces the optical characteristics of the quantum dots.

Therefore, there is a demand for the development of technology that can improve the light resistance of quantum dots.

Furthermore, when forming a coating film using quantum dots, a method is needed to increase the physical properties of the coating film.

One object of the present invention is to provide a quantum dot dispersion that can improve the light resistance and hardness of a coating film.

Another object of the present invention is to provide a curable composition containing the quantum dot dispersion.

Another object of the present invention is to provide a cured film formed using the curable composition.

A further object of the present invention is to provide an image display device including the cured film.

On the other hand, the present invention provides a quantum dot dispersion that contains quantum dots and a compound having a 3- to 6-membered sulfur-containing alicyclic hydrocarbon group.

In one embodiment of the present invention, the compound having a 3- to 6-membered sulfur-containing alicyclic hydrocarbon group may include a compound represented by the following chemical formula 1.

In the above formula,
Z is,

or

and
R ¹ and R ² are each independently an absent or C ₁ -C ₆ alkylene group in which one or more of the chain carbons are unsubstituted or substituted with oxygen;
A is absent, O, ^NR4 or S;
^R3 and ^R4 are each independently hydrogen or a _C1 - _C6 alkyl group;
n and m are each independently an integer from 1 to 4;
p is an integer from 1 to 100.

In one embodiment of the present invention, n and m may be 1.

The quantum dot dispersion according to one embodiment of the present invention may further include at least one of a curable monomer and a solvent.

On the other hand, the present invention provides a curable composition comprising the quantum dot dispersion.

In one embodiment of the present invention, the curable composition may be a photoconversion ink composition, a photoconversion resin composition, or a spontaneous light-emitting photosensitive resin composition.

On the other hand, the present invention provides a cured film formed using the curable composition.

In one embodiment of the present invention, the cured film may be a color filter or a light conversion sheet.

On the other hand, the present invention provides an image display device including the cured film.

The quantum dot dispersion according to the present invention has excellent light resistance of quantum dots and excellent physical properties such as hardness of the coating film when applied to the coating film. Therefore, the quantum dot dispersion according to the present invention can be effectively applied to various fields using quantum dots such as color filters and light conversion sheets, and can realize an image display device with excellent reliability.

The present invention will be explained in more detail below.

One embodiment of the present invention relates to a quantum dot dispersion that includes quantum dots (A) and a compound (B) having a 3- to 6-membered sulfur-containing alicyclic hydrocarbon group.

Quantum dots (A)
In one embodiment of the present invention, the quantum dot refers to a nano-sized semiconductor material. Atoms form molecules, and molecules form small molecular aggregates called clusters to form nanoparticles. When such nanoparticles exhibit semiconductor properties, they are called quantum dots. When the quantum dot receives energy from the outside and becomes excited, it emits energy according to the energy band gap corresponding to the quantum dot itself.

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

The 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 the same; and combinations thereof, and these may be used alone or in combination of two or more kinds.

Specifically, the II-VI group semiconductor compound may be selected from the group consisting of two-element compounds selected from the group consisting of ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, and mixtures thereof; three-element compounds selected from the group consisting of ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, HgZnS, HgZnSe, HgZnTe, and mixtures thereof; and four-element compounds selected from the group consisting of HgZnSeS, HgZnSeTe, HgZnSTe, and mixtures thereof, but are not limited thereto.

The III-V semiconductor compound is a bi-element compound selected from the group consisting of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, and mixtures thereof; GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, and mixtures thereof. 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 are not limited thereto.

The IV-VI semiconductor compound may be one or more selected from the group consisting of two-element compounds selected from the group consisting of SnS, SnSe, SnTe, PbS, PbSe, PbTe, and mixtures thereof; three-element compounds selected from the group consisting of SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, and mixtures thereof; and four-element compounds selected from the group consisting of SnPbSSe, SnPbSeTe, SnPbSTe, and mixtures thereof, but is similarly not limited thereto.

The Group IV element or a compound containing the same may be, but is not limited to, an element selected from the group consisting of Si, Ge, and mixtures thereof; and a two-element compound selected from the group consisting of SiC, SiGe, and mixtures thereof.

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

Specifically, in the core-shell double structure, the materials constituting the core and shell may be made of different semiconductor compounds as described above. For example, the core may be made 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, G The shell may include, but is not limited to, one or more selected from the group consisting of aAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb. The shell may include, but is not limited to, one or more selected from the group consisting of ZnSe, ZnS, and ZnTe.

Preferably, the core-shell quantum dots include InP/ZnS, InP/ZnSe, InP/GaP/ZnS, InP/ZnSe/ZnS, InP/ZnSeTe/ZnS, and InP/MnSe/ZnS.

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

The wet chemical process is a method of growing particles by putting precursor materials into an organic solvent. In the wet chemical process, as the crystals grow, the organic solvent naturally coordinates to the surface of the quantum dot crystals and acts as a dispersant to regulate the growth of the crystals, so the growth of nanoparticles can be controlled by a process that is easier and less expensive than gas phase deposition methods such as metalorganic chemical vapor deposition and molecular beam epitaxy. Therefore, it is preferable to manufacture the quantum dots using the wet chemical process.

When manufacturing quantum dots by wet chemical processes, organic ligands are used to suppress the aggregation of quantum dots and to control the particle size of quantum dots to the nano level. Oleic acid may generally be used as such an organic ligand.

In one embodiment of the present invention, the oleic acid used in the manufacturing process of the quantum dots is replaced by other organic ligands by a ligand exchange method, if necessary.

The ligand exchange may be carried out by adding the organic ligand to be exchanged to a dispersion containing quantum dots having the original organic ligand, i.e., oleic acid, and stirring the mixture at room temperature to 200°C for 30 minutes to 3 hours. If necessary, the quantum dots that have undergone the ligand exchange reaction may be further separated and purified.

Examples of the other organic ligands include, but are not limited to, _C5 - _C20 alkyl carboxylic acids, _C5 - _C20 alkenyl carboxylic acids, _C5 - _C20 alkynyl carboxylic acids, thiols, phosphoric acid, pyridine, mercapto alcohols, phosphines, and phosphine oxides.

The quantum dots (A) may be contained in the range of 5 to 80% by weight, preferably 10 to 70% by weight, based on 100% by weight of the total quantum dot dispersion. When the quantum dots are contained within the above range, the dispersion stability is excellent.

Compound (B) having a 3- to 6-membered sulfur-containing alicyclic hydrocarbon group
In one embodiment of the present invention, the compound (B) having a 3- to 6-membered sulfur-containing alicyclic hydrocarbon group serves as an additive for improving the light resistance of the quantum dots and enhancing physical properties such as hardness when applied to a coating film, and also serves as a dispersion medium for the quantum dots.

Specifically, the compound having a 3- to 6-membered sulfur-containing alicyclic hydrocarbon group can improve the light retention rate of quantum dots that can be affected by blue light sources. In addition, when the quantum dots are applied to a curable composition to form a coating film, the compound having a 3- to 6-membered sulfur-containing alicyclic hydrocarbon group can improve the physical properties of the coating film, such as hardness.

Preferably, the compound having a 3- to 6-membered sulfur-containing alicyclic hydrocarbon group may include a compound represented by the following chemical formula 1.

In the above formula,
Z is,

or

and
R ¹ and R ² are each independently an absent or C ₁ -C ₆ alkylene group in which one or more of the chain carbons is unsubstituted or substituted with oxygen;
A is absent, O, ^NR4 or S;
^R3 and ^R4 are each independently hydrogen or a _C1 - _C6 alkyl group;
n and m are each independently an integer from 1 to 4;
p is an integer from 1 to 100.

As used herein, a _C1 - _C6 alkylene group in which one or more of the chain carbons are substituted or unsubstituted with oxygen refers to a functional group in which one or more of the chain carbons in a straight or branched divalent hydrocarbon having 1 to 6 carbon atoms are substituted or unsubstituted with oxygen, examples of which include, but are not limited to, methylene, ethylene, propylene, butylene, oxyethylene, and the like.

As used herein, a _C1 - _C6 alkyl group means a linear or branched monovalent hydrocarbon group composed of 1 to 6 carbon atoms, including, but not limited to, methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, n-pentyl, n-hexyl, and the like.

In one embodiment of the present invention, n and m may be 1.

The compound (B) having a 3- to 6-membered sulfur-containing alicyclic hydrocarbon group may be contained in an amount of 5 to 95% by weight, preferably 5 to 90% by weight, based on 100% by weight of the entire quantum dot dispersion. If the compound having a 3- to 6-membered sulfur-containing alicyclic hydrocarbon group is contained in an amount of less than 5% by weight, based on 100% by weight of the entire quantum dot dispersion, the dispersibility of the quantum dots may decrease. If the compound is contained in an amount of more than 95% by weight, the dispersion has excellent dispersion characteristics, but the color reproduction characteristics may decrease due to leakage of excitation light when made into a film.

The quantum dot dispersion according to one embodiment of the present invention may further include at least one of a curable monomer (C) and a solvent (D).

Curable Monomer (C)
In one embodiment of the present invention, the curable monomer (C) has reactivity due to the action of light or heat, and acts as a dispersion medium for the quantum dots.

For example, the curable monomer (C) may be a monofunctional monomer, a bifunctional monomer, or another polyfunctional monomer, and among these, a bifunctional monomer is preferably used.
The type of the monofunctional monomer is not particularly limited, and examples thereof include nonylphenylcarbitol acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-ethylhexylcarbitol acrylate, 2-hydroxyethyl acrylate, and N-vinylpyrrolidone.

The type of the bifunctional monomer is not particularly limited, but examples include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, bis(acryloyloxyethyl)ether of bisphenol A, and 3-methylpentanediol di(meth)acrylate.

The type of the polyfunctional 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, and dipentaerythritol hexa(meth)acrylate.

The curable monomer (C) may be contained in an amount of 5 to 80% by weight, preferably 5 to 70% by weight, based on 100% by weight of the total quantum dot dispersion. If the curable monomer is contained in an amount of less than 5% by weight, based on 100% by weight of the total quantum dot dispersion, the dispersibility may decrease or the cured density of the coating film may decrease, causing problems such as wrinkles and cracks during deposition of the metal protective film. If the curable monomer is contained in an amount of more than 80% by weight, the color reproduction characteristics may decrease due to leakage of excitation light.

Solvent (D)
In one embodiment of the present invention, the solvent (D) is not particularly limited and may be an organic solvent commonly used in the technical field.

For example, the solvent may be an ether or ester solvent, an aliphatic saturated hydrocarbon solvent, a halogenated hydrocarbon solvent, an aromatic hydrocarbon solvent, a ketone solvent, an alcohol solvent, or the like.

Specific examples of the ether or ester solvent include propylene glycol monomethyl ether acetate, propylene glycol monopropyl ether acetate, n-pentyl acetate, 3-methoxybutyl acetate, methoxybutyl acetate, methoxypentyl acetate, ethylene glycol monoethyl ether acetate, methyl cellosolve acetate, ethyl cellosolve acetate, ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, γ-butyrolactone, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, and diethylene glycol dibutyl ether.

Examples of the aliphatic saturated hydrocarbon solvent include hexane, pentane, heptane, cyclopentane, cyclohexane, and kerosene.

Examples of the halogenated hydrocarbon solvent include chloroform, dichloromethane, carbon tetrachloride, dichloroethane, and tetrachloroethane.

Examples of the aromatic hydrocarbon solvent include benzene, toluene, xylene, mesitylene, and dichlorobenzene.

Examples of the ketone solvent include methyl ethyl ketone, acetone, methyl amyl ketone, methyl isobutyl ketone, and cyclohexanone.

Examples of the alcohol-based solvent include ethanol, propanol, butanol, hexanol, cyclohexanol, ethylene glycol, and glycerin.

The above solvents may be used alone or in combination of two or more.

The solvent (D) may be contained in the range of 20 to 90% by weight, preferably 25 to 85% by weight, based on 100% by weight of the total quantum dot dispersion. When the solvent is contained within the above range, precipitation of particles in the quantum dot dispersion can be suppressed, and the dispersion has excellent dispersion stability and optical properties, which is advantageous in terms of storage stability of the dispersion.

<Curable Composition>
One embodiment of the present invention relates to a curable composition comprising the quantum dot dispersion described above.
For example, the curable composition may be a light-converting ink composition, a light-converting resin composition, or a spontaneous light-emitting photosensitive resin composition.

In one embodiment of the present invention, the light conversion ink composition may further contain a photopolymerizable monomer and a photopolymerization initiator in addition to the quantum dot dispersion.

The photopolymerizable monomer may be of any type without particular limitation as long as it is a compound that can be polymerized by the action of light and a photopolymerization initiator described below, and may be the same as the curable monomer used in the quantum dot dispersion described above.

The photopolymerizable monomer may be contained in an amount of 20 to 90% by weight, preferably 30 to 80% by weight, relative to 100% by weight of the total photoconversion ink composition. When the photopolymerizable monomer is contained within the above range, it has the advantage of being favorable in terms of the strength and smoothness of the pixel portion. When the photopolymerizable monomer is contained below the above range, the strength of the pixel portion may be slightly decreased, and when the photopolymerizable monomer is contained above the above range, the smoothness may be slightly decreased, so it is preferable that the photopolymerizable monomer is contained within the above range.

The photopolymerization initiator may be of any type, as long as it can polymerize the photopolymerizable monomer. In particular, from the viewpoints of polymerization characteristics, initiation efficiency, absorption wavelength, availability, price, etc., it is preferable to use one or more compounds selected from the group consisting of acetophenone-based compounds, benzophenone-based compounds, triazine-based compounds, biimidazole-based compounds, oxime-based compounds, and thioxanthone-based compounds as the photopolymerization initiator.

The photopolymerization initiator may be contained in the range of 0.01 to 20% by weight, preferably 0.5 to 15% by weight, relative to 100% by weight of the total photoconversion ink composition. When the photopolymerization initiator is contained within the above range, the photoconversion ink composition becomes highly sensitive, shortening the exposure time and 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 of the surface of the pixel portion are improved.

The photopolymerization initiator may further contain a photopolymerization initiation assistant to improve the sensitivity of the photoconversion ink composition according to the present invention. The inclusion of the photopolymerization initiation assistant has the advantage of further increasing the sensitivity and improving productivity.

The photopolymerization initiator aid may be, for example, one or more compounds selected from the group consisting of amine compounds, carboxylic acid compounds, and organic sulfur compounds having a thiol group, but is not limited thereto.

The photopolymerization initiator aid may be added as needed as long as it does not impair the effects of the present invention.

In one embodiment of the present invention, the light conversion ink composition may further include scattering particles.

The scattering particles increase the number of paths for the light emitted from the quantum dots, thereby increasing the overall light efficiency.

The scattering particles may be made of a normal inorganic material, preferably a metal oxide.

The metal oxide may be an oxide containing one or more metals 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, it _may be one selected from the _group consisting of _Al2O3 , _SiO2 , _{ZnO, ZrO2, BaTiO3, TiO2, Ta2O5, Ti3O5 , ITO , IZO , ATO} , ZnO-Al, _Nb2O3 , SnO, MgO, and combinations thereof. If necessary, a material that has been surface-treated with a compound having an unsaturated bond, such as acrylate, may 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, it is not possible to expect a sufficient scattering effect of the light emitted from the quantum dots, and conversely, if the particle size is too large, it may sink in the composition and it may be impossible to obtain a light conversion layer surface of uniform quality, so the particle size should be adjusted appropriately within the above range.

In the present invention, the average particle size may refer to the number average particle size, and can be determined, for example, from images observed with a field emission scanning electron microscope (FE-SEM) or a transmission electron microscope (TEM). Specifically, it can be obtained by extracting several samples from the FE-SEM or TEM observation images, measuring the diameters of these samples, and taking the arithmetic average value.

The scattering particles may be contained in the range of 0.5 to 20% by weight, preferably 1 to 15% by weight, based on 100% by weight of the total light conversion ink composition. When the scattering particles are contained within the above range, the effect of increasing the luminous intensity is maximized, which is preferable. When the scattering particles are contained below the above range, it may be difficult to ensure the desired luminous intensity, and when the scattering particles are contained above the above range, the transmittance of blue irradiation light decreases, which may cause problems with luminous efficiency.

In addition to the components described above, the light conversion ink composition according to one embodiment of the present invention may further contain additives such as surfactants and adhesion promoters to improve the flatness and adhesion of the coating film.

The light conversion ink composition according to one embodiment of the present invention may be a solvent-based or solventless type, and from the viewpoint of continuous processing, the solventless type is preferred.

When the photoconversion ink composition is a solvent-free type, it does not substantially contain a solvent, and even if it does contain a solvent, it may contain an amount of 2% by weight or less based on 100% by weight of the total photoconversion ink composition.

If the light conversion ink composition is a solvent-based composition, the same solvent as described above for the quantum dot dispersion may be used.

In one embodiment of the present invention, the photoconversion resin composition further contains a curable resin in addition to the quantum dot dispersion.

The curable resin acts as a dispersion medium for the quantum dots and as a binder resin.

The curable resin may be a transparent polymer that transmits light, and in particular, a resin with low moisture and air permeability may be used to prevent deterioration of the quantum dots.

For example, the curable resin may include epoxy resin, acrylic resin, epoxy acrylate resin, polyvinyl acetate, polyvinyl alcohol, polyethylene, polypropylene, polycarbonate, polyvinyl chloride, etc., either alone or in combination, and may particularly include epoxy resin.

The polystyrene-equivalent weight average molecular weight (hereinafter, abbreviated as "weight average molecular weight") of the curable resin measured by gel permeation chromatography (GPC; using tetrahydrofuran as an elution solvent) is preferably in the range of 5,000 g/mol to 50,000 g/mol, and more preferably 8,000 g/mol to 40,000 g/mol. If the weight average molecular weight is within the above range, it is preferable because it has the advantage of increasing the hardness of the coating film.

The curable resin may be contained in an amount ranging from 5 to 60% by weight, preferably 10 to 50% by weight, based on 100% by weight of the total solid content of the photoconversion resin composition. If the curable resin is contained in an amount less than 5% by weight, it may be difficult to obtain a thick cured film in the process, and if it is contained in an amount exceeding 60% by weight, it may be difficult to form a cured film of uniform thickness.

In one embodiment of the present invention, the light-converting resin composition may further include scattering particles, a solvent, a dispersant, and/or a curing agent.

The scattering particles may be the same as those used in the light conversion ink composition described above.

The scattering particles may be contained in an amount ranging from 0.5 to 30% by weight, based on 100% by weight of the total solid content of the light-converting resin composition. If the scattering particles are contained in an amount less than 0.5% by weight, the light scattering effect may be too low to obtain an appropriate light output for use in a coating film, and if the scattering particles are contained in an amount exceeding 30% by weight, the scattering effect may be too strong, and the light emitted by the quantum dots may not be able to transmit or pass through the coating film, resulting in a decrease in light output.

The solvent may be the same as that described for the quantum dot dispersion above.

The dispersant has a deagglomeration effect on the quantum dots. The dispersant may be a compound containing a carboxylic acid and an unsaturated double bond.

The curing agent may be an epoxy compound, a polyfunctional isocyanate compound, an oxetane compound, or the like.

The photoconversion resin composition according to the present invention may further contain additives such as surfactants, adhesion promoters, antioxidants, UV absorbers, and anti-aggregation agents, as necessary.

In one embodiment of the present invention, the spontaneously luminous photosensitive resin composition further contains an alkali-soluble resin, a photopolymerizable monomer, and a photopolymerization initiator in addition to the quantum dot dispersion.

The alkali-soluble resin can make the non-exposed areas of the pattern produced from the spontaneous light-emitting photosensitive resin composition alkali-soluble and removable, while allowing the exposed areas to remain. In addition, when the spontaneous light-emitting photosensitive resin composition contains the alkali-soluble resin, it can make the quantum dots uniformly disperse in the composition and protect the quantum dots during the process to maintain their brightness.

The alkali-soluble resin may be selected to have an acid value in the range of 50 to 200 (KOH mg/g). The "acid value" is a value measured as the amount (mg) of potassium hydroxide required to neutralize 1 g of polymer, and is related to solubility. If the acid value of the alkali-soluble resin is below the above range, it may be difficult to ensure a sufficient development speed, and if it exceeds the above range, adhesion to the substrate may decrease, making the pattern more susceptible to short circuits, and the storage stability of the entire composition may decrease, resulting in an increase in viscosity.

The weight average molecular weight of the alkali-soluble resin may be in the range of 3,000 to 30,000, preferably 5,000 to 20,000, and the molecular weight distribution may be in the range of 1.5 to 6.0, preferably 1.8 to 4.0.

The alkali-soluble resin may be a polymer of a carboxyl-containing unsaturated monomer, or a copolymer of the polymer and a monomer having an unsaturated bond copolymerizable therewith, or a combination thereof.

The carboxyl group-containing unsaturated monomer includes unsaturated monocarboxylic acid, unsaturated dicarboxylic acid, unsaturated tricarboxylic acid, etc. Specific examples of unsaturated monocarboxylic acid include acrylic acid, methacrylic acid, crotonic acid, α-chloroacrylic acid, cinnamic acid, etc. Specific examples of unsaturated dicarboxylic acid include maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, etc. The unsaturated dicarboxylic acid may be an acid anhydride, and specific examples thereof include maleic anhydride, itaconic anhydride, citraconic anhydride, etc. The unsaturated dicarboxylic acid may also be a mono(2-(meth)acryloyloxyalkyl)ester thereof, and examples thereof include mono(2-acryloyloxyethyl) succinate, mono(2-methacryloyloxyethyl) succinate, mono(2-acryloyloxyethyl) phthalate, and mono(2-methacryloyloxyethyl) phthalate. The unsaturated dicarboxylic acid may be a mono(meth)acrylate of a polymer having dicarboxy groups at both ends thereof, such as ω-carboxypolycaprolactone monoacrylate, ω-carboxypolycaprolactone monomethacrylate, etc. These carboxyl group-containing monomers may be used alone or in combination of two or more kinds.
In addition, the monomer copolymerizable with the carboxyl group-containing unsaturated monomer may be one selected from the group consisting of aromatic vinyl compounds, unsaturated carboxylic acid ester compounds, unsaturated carboxylic acid amino alkyl ester compounds, unsaturated carboxylic acid glycidyl ester compounds, carboxylic acid vinyl ester compounds, unsaturated ether compounds, vinyl cyanide compounds, unsaturated amide compounds, unsaturated imide compounds, aliphatic conjugated diene compounds, macromonomers having a monoacryloyl group or a monomethacryloyl group at the molecular chain terminal, bulky monomers, and combinations thereof.

The alkali-soluble resin may be contained in a range of 5 to 80% by weight, specifically 10 to 70% by weight, more specifically 15 to 60% by weight, based on 100% by weight of the total solid content of the self-luminous photosensitive resin composition.

The photopolymerizable monomer may be the same as the curable monomer used in the quantum dot dispersion described above, so long as it is a compound that can be polymerized by the action of light and a photopolymerization initiator described below.

The photopolymerizable monomer may be contained in the range of 5 to 70% by weight, specifically 10 to 60% by weight, more specifically 15 to 50% by weight, based on 100% by weight of the total solid content of the self-luminous photosensitive resin composition.

The photopolymerization initiator may be the same as that used in the photoconversion ink composition described above, and may further contain a photopolymerization initiator assistant as necessary.

The photopolymerization initiator may be contained in the range of 0.1 to 20% by weight, preferably 0.5 to 15% by weight, and more preferably 1 to 10% by weight, based on 100% by weight of the total solid content of the self-luminous photosensitive resin composition.

The spontaneous light-emitting photosensitive resin composition may further contain a solvent, and the solvent may be the same as that described for the quantum dot dispersion above.

The content of the solvent in the self-luminous photosensitive resin composition may be in the range of 20 to 90% by weight, preferably 25 to 85% by weight, and more preferably 30 to 80% by weight, based on 100% by weight of the entire self-luminous photosensitive resin composition.

The self-luminous photosensitive resin composition according to the present invention may further contain additives such as adhesion promoters, surfactants, antioxidants, ultraviolet absorbers, and anti-aggregation agents, as necessary.

<Cured film>
One embodiment of the present invention relates to a cured film formed using the above-mentioned curable composition.

In one embodiment of the present invention, the cured film may be a color filter or a light conversion sheet.

The color filter and light conversion sheet according to the present invention contain a cured product of a curable composition containing the quantum dot dispersion according to the present invention, and therefore have the advantage of excellent light resistance of the quantum dots and excellent hardness of the coating film.

The color filter includes a substrate and a patterned layer formed on top of the substrate.

The substrate may be the substrate of the color filter itself, or may be a portion of a display device or the like where the color filter is located, and is not particularly limited. The substrate may be a glass, silicon (Si), silicon oxide (SiOx), Al, GaAs, or polymer substrate, and the polymer may be polyethersulfone, polycarbonate, polyester, aromatic polyamide, polyamideimide, polyimide, or the like. The substrate may have a partition matrix formed thereon.

The pattern layer is a layer containing the curable composition according to the present invention, and may be patterned by an inkjet printing patterning method or by photolithography.

The pattern formation method using the inkjet printing patterning method may be performed by applying the above-mentioned curable composition to a predetermined area by an inkjet method and curing the applied curable composition.

First, the curable composition of the present invention is injected into an inkjet printer and printed onto a specified area of a substrate.

In order for the ink to be sprayed from a piezoelectric inkjet head, which is an example of an inkjet sprayer, and to form the appropriate phase on the substrate, the properties of the viscosity, fluidity, quantum dot particles, etc. must be balanced with the inkjet head. The piezoelectric inkjet head used in the present invention sprays ink with a droplet size of about 10 to 100 pL, preferably about 20 to 40 pL, although there is no limit to this.

When using the inkjet printing patterning method, the viscosity of the curable composition according to the present invention is suitably adjusted to a range of about 3 to 30 cP, and more preferably, to a range of 7 to 20 cP.

The pattern formation method using the photolithography method may be performed by applying the above-mentioned curable composition, exposing it to a predetermined pattern, developing it, and thermally curing it. The pattern formation method using the photolithography method may be performed by a method commonly known in the technical field.

The color filter may include only two pattern layers of different hues, a red pattern layer, a green pattern layer, and a blue pattern layer, but is not limited to this. In addition, when the color filter includes only two pattern layers of different hues, the pattern layers may further include a transparent pattern layer that does not contain the quantum dot particles.

When the color filter has only pattern layers of the two hues, a light source that emits light of a wavelength that exhibits a hue other than the two hues may be used. For example, when the color filter includes a red pattern layer and a green pattern layer, a light source that emits blue light may be used, in which case the red quantum dots emit red light and the green quantum dots emit green light, and the transparent pattern layer may exhibit blue by allowing the blue light from the light source to pass through.

The light conversion sheet is a sheet that converts the wavelength of light emitted by the light emitting element and emits it.

The light conversion sheet may further include a substrate.

The light conversion sheet may be formed by applying the above-mentioned curable composition onto a substrate, drying it, and then curing it.

The substrate may be subjected to a release treatment as necessary.

The substrate may be glass or a polyethylene terephthalate (PET) film.

The curing may be carried out under heat or light curing conditions.

<Image display device>
One embodiment of the present invention relates to an image display device including the above-mentioned cured film.

The cured film described above in the image display device according to one embodiment of the present invention may be applied as a color filter or a light conversion sheet, and thus may be used in the manufacture of a color filter substrate or a light source for a backlight unit.

The cured film according to the present invention can be applied to various image display devices, such as not only ordinary liquid crystal display devices (LCDs), but also electroluminescent display devices (ELs), plasma display devices (PDPs), field emission display devices (FEDs), organic light-emitting devices (OLEDs), and quantum dot light-emitting diodes (QLEDs).

The image display device according to the present invention includes a configuration known in the art, except that it is provided with the above-mentioned cured film.

The quantum dots according to one embodiment of the present invention can be used not only in the displays described above, but also as materials for lighting sources, solar cells, semiconductor lasers/optical amplifiers, bioimaging, and the like.

Hereinafter, the present invention will be described in more detail with reference to examples, comparative examples, and experimental examples. Note that it will be obvious to those skilled in the art that these examples, comparative examples, and experimental examples are merely for the purpose of explaining the present invention, and that the scope of the present invention is not limited to these examples, comparative examples, and experimental examples.

Synthesis Example 1: Synthesis of quantum dots (A-1) 0.05839 g of indium acetate, 0.12019 g of oleic acid, and 10 mL of 1-octadecene (ODE) were placed in a three-neck flask. The flask was degassed at 110° C. and 100 mTorr for 30 minutes while stirring, and then heated at 270° C. under an inert gas until the solution became transparent.

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

3.669 g of zinc acetate, 20 mL of oleic acid, and 20 mL of 1-octadecene were placed in a three-neck flask, and the mixture was degassed at 110°C and 100 mTorr for 30 minutes while stirring. The mixture was then heated at 270°C under an inert gas until the solution became transparent, and then cooled to 60°C to obtain a transparent precursor solution of zinc oleate.

0.6412 g of sulfur and 10 mL of tri-n-octylphosphine were placed in a three-neck flask, heated at 80°C while stirring in an inert gas atmosphere until the solution became transparent, and then cooled to room temperature to obtain a TOP:S-type S precursor solution.

A separate three-neck flask was filled with the InP core nanoparticle solution, and the flask temperature was adjusted to 300°C. Then, 0.6 mL of the zinc precursor solution was quickly injected using a syringe. Then, 0.3 mL of the S precursor solution was injected into the flask at a rate of 2 mL/hr using a syringe pump. After the injection, the reaction was continued for another 3 hours and then quickly cooled to terminate the reaction. When the flask temperature reached 100°C, 10 mL of toluene was injected and then transferred to a 50 mL centrifuge tube. After adding 10 mL of ethanol, the mixture was purified twice using the precipitation and redispersion method. The purified InP/ZnS core-shell structured nanoparticles were dispersed in n-chloroform and stored. The solid content was adjusted to 25 wt%. The maximum emission wavelength was 525 nm.

Synthesis Example 2: Synthesis of quantum dots (A-2) 0.4 mmol (0.058 g) of indium acetate, 0.6 mmol (0.15 g) of palmitic acid, and 20 mL of 1-octadecene were placed in a reactor and heated at 120° C. under vacuum. After 1 hour, the atmosphere in the reactor was replaced with nitrogen. After heating at 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 quickly injected and reacted for 0.5 minutes.

Next, 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 replaced with 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 in trioctylphosphine (Se/TOP), 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 centrifuging was filtered under reduced pressure and dried under reduced pressure to form an InP/ZnSe core-shell.

Next, 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 replaced with 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 in trioctylphosphine (S/TOP), and the final mixture was reacted for 2 hours. Ethanol was added to the reaction solution that was quickly cooled to room temperature, and the precipitate obtained by centrifuging was filtered under reduced pressure and dried under reduced pressure to obtain quantum dots with an InP/ZnSe/ZnS core-shell structure, which were then dispersed in chloroform. The solid content was adjusted to 25% by weight. The maximum emission wavelength was 520 nm.

Examples and Comparative Examples: Preparation of Quantum Dot Dispersion A quantum dot dispersion was prepared by mixing the components according to the composition in Table 1 below (wt %).

Examples and Comparative Examples: Preparation of Light-Converting Ink Compositions Light-converting ink compositions were prepared by mixing the components according to the compositions in Tables 2 and 3 below (wt %).

Experimental Example 1:
The viscosity stability, dispersion particle size, and light resistance of the quantum dot dispersions prepared in the above examples and comparative examples were measured by the following methods, and the results are shown in Table 4 below.

(1) Viscosity Stability For the quantum dot dispersions of Examples 1 to 15 and Comparative Examples 1 to 4, the initial viscosity was measured at a rotation speed of 10 rpm and a temperature of 30° C. using an R-type viscometer (VISCOMETER MODEL RE120L SYSTEM, manufactured by Toki Sangyo Co., Ltd.) and the viscosity after one month of storage at a low temperature of 5° C. The viscosity stability was evaluated based on the rate of viscosity change according to the following evaluation criteria.

<Evaluation criteria>
◯: Viscosity change rate 105% or less △: Viscosity change rate from 105% to 110% or less ×: Viscosity change rate over 110% (2) Dispersion particle size The dispersion particle size of the quantum dot dispersions of Examples 1 to 15 and Comparative Examples 1 to 4 was measured using ELSZ-2000ZS (manufactured by Otsuka Electronics Co., Ltd.).

(3) Light resistance (light retention rate)
The quantum efficiency (QY%) of the quantum dot dispersion immediately after preparation and after standing at room temperature for 15 days were measured using a PL spectrophotometer and a UV-Vis spectrophotometer.

When the surface of a quantum dot is oxidized, the quantum efficiency decreases, so the amount of quantum efficiency decrease can be measured to confirm light resistance (light retention rate). In other words, light resistance can be confirmed by measuring ΔQY%.

As shown in Table 4, it was confirmed that the quantum dot dispersion of the embodiment containing a compound having a 3- to 6-membered sulfur-containing alicyclic hydrocarbon group has significantly improved viscosity stability, dispersion particle size, and light resistance compared to the quantum dot dispersion of the comparative example not containing a compound having a 3- to 6-membered sulfur-containing alicyclic hydrocarbon group.

Experimental Example 2:
The light conversion coating layer was prepared as described below using the light conversion ink compositions prepared in the above examples and comparative examples, and the light conversion efficiency, light resistance (light retention rate), number of continuous jetting, and hardness of the coating were measured as described below, and the results are shown in Table 5 below.

<Production of light conversion coating layer>
Each of the light conversion ink compositions prepared in the examples and comparative examples was applied onto a 5 cm x 5 cm glass substrate by the inkjet method, and then irradiated with 100 mJ/ ^cm2 using a 1 kW high pressure mercury lamp containing g, h, and i rays as an ultraviolet light source, and then heated in a heating oven at 180°C for 30 minutes to prepare a light conversion coating layer.

(1) Light Conversion Efficiency The prepared light conversion coating layer was placed on top of a blue light source (XLamp XR-E LED, Royal blue 450, manufactured by Cree), and the light conversion efficiency was measured using a luminance meter (CAS140CT Spectrometer, manufactured by Instrument Systems) according to the following mathematical formula 1.
The higher the light conversion efficiency (%), the better the brightness that can be obtained.

(2) Light resistance (light retention rate)
The prepared light conversion coating layer was placed above a blue light source (XLamp XR-E LED, Royal blue 450, manufactured by Cree), and the initial light conversion efficiency was calculated using a luminance meter (CAS140CT Spectrometer, manufactured by Instrument Systems) according to Equation 1. Then, the light conversion coating layer was irradiated with a 450 nm LED with an illuminance of 80 mW/ ^cm2 for 3 days, and the light conversion efficiency was measured as described above, and the light retention was calculated from the light conversion efficiency according to Equation 2 below.

(3) Number of Continuous Jettings The light conversion ink compositions of Examples 16 to 30 and Comparative Examples 5 to 9 were filled into an inkjet printing device manufactured by Unijet Co., Ltd., and the temperature of the jetting head was fixed at 40° C., and the ink was ejected for 1 minute. Thereafter, the ink was left for 30 minutes. This was repeated until the nozzle of the jetting head became clogged and ejection became impossible, and the number of continuous jettings was evaluated.

The more consecutive jetting times you do, the better the continuous process you can achieve.

(4) Hardness of Coating Film The hardness of the prepared light conversion coating layer was measured at a high temperature of 150° C. using a hardness tester (HM500; manufactured by Fischer), and the surface hardness was evaluated according to the following evaluation criteria.

<Evaluation criteria>
○: Surface hardness of 50 N/mm2 ^or more △: Surface hardness of 30 N/mm2 ^or more and less than 50 N/ ^mm2 ×: Surface hardness of less than 30 N/ ^mm2

As shown in Table 5, it was confirmed that the light conversion ink composition of the example using a quantum dot dispersion containing a compound having a 3- to 6-membered sulfur-containing alicyclic hydrocarbon group was superior in light conversion efficiency, light resistance (light retention rate), number of continuous jetting, and hardness of the coating film compared to the light conversion ink composition of the comparative example using a quantum dot dispersion not containing a compound having a 3- to 6-membered sulfur-containing alicyclic hydrocarbon group.

Although specific aspects of the present invention have been described in detail above, it will be clear to anyone with ordinary knowledge in the technical field to which the present invention pertains that these specific descriptions are merely preferred examples and do not limit the scope of the present invention. Anyone with ordinary knowledge in the technical field to which the present invention pertains will be able to make various applications and modifications within the scope of the present invention based on the above content.

Therefore, the true scope of the present invention is defined by the claims and their equivalents.

Claims (8)

The present invention relates to a compound having a quantum dot and a 3- to 6-membered sulfur-containing alicyclic hydrocarbon group,
The quantum dot dispersion includes a compound having a 3- to 6-membered sulfur-containing alicyclic hydrocarbon group, the compound being represented by the following chemical formula 1 :

In the above formula,
Z is,

or

and
R ¹ and R ² are each independently an absent or C ₁ -C ₆ alkylene group in which one or more of the chain carbons are unsubstituted or substituted with oxygen;
A is absent, O, NR4 ^or S;
R3 and R4 ^are each independently hydrogen or a C1 ^- _C6 alkyl _group ;
n and m are each independently an integer from 1 to 4;
p is an integer from 1 to 100. 2. The quantum dot dispersion of claim 1 , wherein n and m are 1. The quantum dot dispersion of claim 1, further comprising at least one of a curable monomer and a solvent. A curable composition comprising the quantum dot dispersion according to any one of claims 1 to 3 . The curable composition according to claim 4 , which is a light-converting ink composition, a light-converting resin composition, or a spontaneous light-emitting photosensitive resin composition. A cured film formed by using the curable composition according to claim 4 . The cured film according to claim 6 , which is a color filter or a light conversion sheet. An image display device comprising the cured film according to claim 6 .