TWI901202B - Curable composition, cured layer using the composition and display device including the cured layer - Google Patents

Abstract

Provided are a curable composition, a cured layer manufactured using the same, and a display device including the cured layer, the curable composition including (A) quantum dots; and (B) a polymerizable compound, wherein the polymerizable compound includes a first polymerizable compound having a refractive index of greater than or equal to 1.5 and a viscosity of greater than or equal to 10 cps and including a benzene ring and a second polymerizable compound having a different structure from the first polymerizable compound and including a thiophene ring or a furan ring.

Description

Curable composition, cured layer using the composition, and display device including the cured layer

[Cross-reference to related applications]

This application claims priority to and the benefits of Korean Patent Application No. 10-2023-0078534, filed on June 19, 2023, with the Korean Intellectual Property Office, and Korean Patent Application No. 10-2024-0076544, filed on June 12, 2024, with the Korean Intellectual Property Office. The entire contents of those Korean patent applications are incorporated herein by reference.

The present disclosure relates to a curable composition, a curable layer using the composition, and a display device including the curable layer.

In the case of general quantum dots, due to their hydrophobic surface properties, the solvents in which they can be dispersed are limited, and therefore they are difficult to introduce into polar systems (such as adhesives or curable monomers).

For example, even in the case of quantum dot ink compositions, which are being actively studied, polarity is relatively low in the initial stage, and the quantum dot ink composition can be dispersed in the solvent used in the highly hydrophobic curable composition. Therefore, since it is difficult to include 20% or more of quantum dots based on the total composition, it is impossible to increase the optical efficiency of the ink beyond a certain level. Even if quantum dots are added and dispersed to increase the optical efficiency, the viscosity will exceed the range that allows inkjetting, and thus processability may be unsatisfactory.

To achieve a viscosity range suitable for inkjetting, one approach is to reduce the ink solids content by dissolving 50% or more of a solvent, based on the total composition. This approach also provides somewhat satisfactory results in terms of viscosity. However, while this approach may be considered satisfactory in terms of viscosity, it can worsen nozzle drying and clogging due to solvent volatilization during inkjetting, as well as a decrease in thickness of a single layer over time after inkjetting. Furthermore, controlling thickness variations after curing is difficult, making it difficult to apply this approach to actual manufacturing processes.

Therefore, solvent-free quantum dot inks, which do not contain solvents, are the most desirable form for practical applications. Current technologies for applying quantum dots themselves to solvent-based compositions are currently subject to certain limitations.

In the case of solvent-free curable compositions (quantum dot ink compositions), the inclusion of an excessive amount of polymerizable compounds can lead to nozzle drying due to volatility, resulting in clogging and ejection failure. Furthermore, the ink composition can evaporate within patterned partition wall pixels, potentially reducing the thickness of the single film. Consequently, various efforts are underway to improve the optical properties of solvent-free curable compositions. Increasing the content of inorganic materials is a common approach to improving the optical properties of solvent-free curable compositions, but the problem is that increasing the content of inorganic materials increases reflectivity. In other words, improving the optical properties of solvent-free curable compositions and reducing their reflectivity are two issues that represent a trade-off, and there is a growing demand for technologies that can simultaneously improve both properties (improving optical properties and reducing reflectivity).

One embodiment provides a curable composition that can improve light absorption and increase light efficiency.

Another embodiment provides a cured layer manufactured using the curable composition.

Another embodiment provides a display device including the solidified layer.

One embodiment provides a curable composition comprising: (A) quantum dots; and (B) a polymerizable compound, wherein the polymerizable compound includes: a first polymerizable compound having a refractive index greater than or equal to 1.5 and a viscosity greater than or equal to 10 centipoise and including a benzene ring; and a second polymerizable compound having a structure different from that of the first polymerizable compound and including a thiophene ring or a furan ring.

The first polymerizable compound may have a refractive index greater than or equal to 1.56.

The first polymerizable compound may be represented by Chemical Formula 1. [Chemical Formula 1]

In Chemical Formula 1, ^X1 and ^X2 are each independently an oxygen atom or a sulfur atom, ^R1 and ^R2 are each independently a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group, and ^L1 is a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C1 to C20 oxyalkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, or a combination thereof.

Chemical formula 1 can be represented by Chemical formula 1-1. [Chemical formula 1-1]

In Chemical Formula 1-1, ^X1 and ^X2 are each independently an oxygen atom or a sulfur atom, ^R1 and ^R2 are each independently a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group, and ^L1 is a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C1 to C20 oxyalkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, or a combination thereof.

The first polymerizable compound can be represented by Chemical Formula 1-1-1 or Chemical Formula 1-1-2. [Chemical Formula 1-1-1] [Chemical formula 1-1-2]

The second polymerizable compound can be represented by Chemical Formula 2. [Chemical Formula 2]

In Chemical Formula 2, ^X3 and ^X4 are each independently an oxygen atom or a sulfur atom, ^R3 is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group, ^L2 is a single bond or a substituted or unsubstituted C1 to C20 alkylene group, ^L3 is a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C1 to C20 oxyalkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, or a combination thereof, and n is an integer from 1 to 4.

Chemical formula 2 can be represented by Chemical formula 2-1. [Chemical formula 2-1]

In Chemical Formula 2-1, ^X3 and ^X4 are each independently an oxygen atom or a sulfur atom, ^R3 is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group, ^L2 is a single bond or a substituted or unsubstituted C1 to C20 alkylene group, and ^L3 is a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C1 to C20 oxyalkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, or a combination thereof.

The second polymerizable compound may include at least one selected from Chemical Formula 2-1-1 to Chemical Formula 2-1-3. [Chemical Formula 2-1-1] [Chemical formula 2-1-2] [Chemical formula 2-1-3]

The second polymerizable compound may have a refractive index greater than or equal to 1.5 and a viscosity less than 10 centipoise.

The first polymerizable compound and the second polymerizable compound may be included in a weight ratio of 1:9 to 9:1.

The curable composition may be a solvent-free curable composition.

The solvent-free curable composition may include, based on the total amount of the solvent-free curable composition, 5 wt % to 60 wt % of quantum dots; and 40 wt % to 95 wt % of the polymerizable compound.

The curable composition may further include a polymerization initiator, a photodiffuser, a polymerization inhibitor, or a combination thereof.

The light diffuser may include barium sulfate, calcium carbonate, titanium dioxide, zirconium oxide, or a combination thereof.

Quantum dots may include cadmium-free luminescent materials.

Quantum dots can have an InP/ZnS core/shell structure or an InP/ZnSe/ZnS core/first shell/second shell structure.

The quantum dot may include a core containing silver (Ag), indium (In), gallium (Ga), and sulfur (S) and a shell containing at least two or more selected from the group consisting of silver (Ag), gallium (Ga), zinc (Zn), and sulfur (S).

The curable composition may further include a solvent.

The curable composition may include, based on the total weight of the curable composition: 1 wt % to 40 wt % of quantum dots; 1 wt % to 20 wt % of a polymerizable compound; and 40 wt % to 80 wt % of a solvent.

The curable composition may further include: malonic acid; 3-amino-1,2-propanediol; a silane coupling agent; a leveling agent; a fluorine-based surfactant; or a combination thereof.

Another embodiment provides a cured layer produced using the curable composition.

Another embodiment provides a display device, comprising the solidified layer.

Other embodiments of the present invention are included in the following detailed description.

By including a highly refractive and highly viscous (meth)acrylate compound having a novel structure in a curable composition containing quantum dots, the light absorptivity and light efficiency of the curable composition containing quantum dots can be improved. Consequently, in a display panel manufactured using the curable composition, the brightness of the pixels can be increased, external light reflection can be reduced, and front-side brightness can be improved.

The embodiments of the present invention are described in detail below. However, these embodiments are exemplary and the present invention is not limited thereto. The present invention is defined by the scope of the patent application.

As used herein, when no definition is otherwise provided, “alkyl” refers to a C1 to C20 alkyl group, “alkenyl” refers to a C2 to C20 alkenyl group, “cycloalkenyl” refers to a C3 to C20 cycloalkenyl group, “heterocycloalkenyl” refers to a C3 to C20 heterocycloalkenyl group, “aryl” refers to a C6 to C20 aryl group, “arylalkyl” refers to a C6 to C20 arylalkyl group, “alkylene” refers to a C1 to C20 alkylene group, “arylene” refers to a C6 to C20 arylene group, “alkylarylene” refers to a C6 to C20 alkylarylene group, “heteroarylene” refers to a C3 to C20 heteroarylene group, and “alkoxylene” refers to a C1 to C20 alkoxylene group.

When no specific definition is otherwise provided, "substituted" as used herein means that at least one hydrogen atom is replaced by a substituent selected from the following: a halogen atom (F, Cl, Br or I), a hydroxyl group, a C1 to C20 alkoxy group, a nitro group, a cyano group, an amine group, an imine group, an azido group, an amidino group, a hydrazine group, a hydrazone group, a carbonyl group, a carbamyl group, a thiol group, an ester group, an ether group, a carboxyl group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C1 to C20 alkyl group, a C2 to C20 alkenyl group, a C2 to C20 alkynyl group, a C6 to C20 aryl group, a C3 to C20 cycloalkyl group, a C3 to C20 cycloalkenyl group, a C3 to C20 cycloalkynyl group, a C2 to C20 heterocycloalkyl group, a C2 to C20 heterocycloalkenyl group, a C2 to C20 heterocycloalkynyl group, a C3 to C20 heteroaryl group, or a combination thereof.

When no specific definition is provided otherwise, the term "hetero" as used herein means a chemical formula containing at least one heteroatom selected from N, O, S, and P.

When a specific definition is not otherwise provided, as used herein, “(meth)acrylate” refers to both “acrylate” and “methacrylate”, and “(meth)acrylic acid” refers to both “acrylic acid” and “methacrylic acid”.

When no specific definition is otherwise provided, the term "combination" as used herein means mixing or copolymerization.

In this specification, when no definition is otherwise provided, when a chemical bond is not drawn where indicated in a chemical formula, a hydrogen bond is indicated at the position.

In addition, in this specification, when no other definition is provided, "*" refers to a point of connection with the same or different atoms or chemical formulas.

Hereinafter, each component constituting the curable composition according to the embodiment will be described in detail.

The quantum dot-containing curable composition according to the embodiment comprises: a polymerizable compound (first polymerizable compound) having a high refractive index and high viscosity, specifically a compound having a refractive index greater than or equal to 1.5 and a viscosity greater than or equal to 10 centipoise (first polymerizable compound) and including a benzene ring, more specifically a compound having a refractive index greater than or equal to 1.56 and including a benzene ring having two substituents, one of which always includes a (meth)acrylate group at the terminal end (first polymerizable compound); and a second polymerizable compound having a different structure from the first polymerizable compound and including a thiophene ring or a furan ring. This improves the light absorption and light efficiency of the curable composition according to the embodiment, ultimately providing a display panel with improved front-side brightness. This effect is believed to be achieved by mixing the first polymerizable compound having high refractive index and high viscosity with the second polymerizable compound. (First polymerizable compound)

The quantum dot-containing curable composition according to the embodiment includes a compound having a high refractive index and a high viscosity as the first polymerizable compound among the polymerizable compounds. Specifically, it includes a compound having a refractive index greater than or equal to 1.5 and a viscosity greater than or equal to 10 centipoise and including a benzene ring. More specifically, it includes a compound having a refractive index greater than or equal to 1.56 and including a benzene ring with two substituents, wherein one of the substituents always includes a (meth)acrylate group at the end, and the other includes a compound that does not include a (meth)acrylate group. Therefore, the light absorptivity and light efficiency of the curable composition according to the embodiment can be improved.

For example, the first polymerizable compound can be represented by Chemical Formula 1. [Chemical Formula 1]

In Chemical Formula 1, ^X1 and ^X2 are each independently an oxygen atom or a sulfur atom, ^R1 and ^R2 are each independently a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group, and ^L1 is a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C1 to C20 oxyalkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, or a combination thereof.

The disadvantages of curable compositions containing green quantum dots are their relatively low absorptivity (ABS) and light efficiency (EQE) compared to curable compositions containing red quantum dots, and their reflectivity is nearly twice as high. Therefore, the technical task of increasing the brightness of green quantum dot pixels in display panels and further improving front-side brightness by reducing external light reflection remains unresolved.

The inventors have clearly solved the above-mentioned problems, conducted relevant research for a long time and underwent hundreds of repeated experiments to improve the optical properties of a curable composition containing green quantum dots and reduce the reflectivity of the curable composition containing green quantum dots. They solved the above-mentioned technical problems by applying a compound represented by Chemical Formula 1, having a refractive index greater than or equal to 1.5 and a viscosity greater than or equal to 10 centipoise and including a benzene ring, as a first polymerizable compound and mixing the first polymerizable compound with a second polymerizable compound described later.

Generally speaking, the primary method for improving the optical properties of curable compositions containing green quantum dots is to increase the inorganic material content. Conversely, the primary method for reducing the reflectivity of curable compositions containing green quantum dots is to reduce the inorganic material content. Because improving optical properties and reducing reflectivity are relative physical properties (i.e., there is a trade-off between improving optical properties and reducing reflectivity), achieving both simultaneously is extremely difficult.

According to an embodiment, a benzene ring-containing compound represented by Chemical Formula 1, having a refractive index greater than or equal to 1.5 and a viscosity greater than or equal to 10 centipoise, and substituted with a terminal substituent containing a (meth)acrylate group, is used as the first polymerizable compound in a curable composition. This can simultaneously achieve the effects of improving optical properties and reducing reflectivity in curable compositions containing both red quantum dots and green quantum dots.

Specifically, the improved optical properties are due to the fact that the refractive index and viscosity of the first polymerizable compound are both high. For example, since the compound represented by Chemical Formula 1 can have a refractive index greater than or equal to 1.5 (e.g., 1.56 to 1.7) and a viscosity greater than or equal to 10 centipoise (e.g., 10 centipoise to 100 centipoise), the optical properties of the curable composition containing the compound represented by Chemical Formula 1 as a polymerizable compound containing quantum dots can be significantly improved.

Furthermore, a reflectivity-reducing effect can be achieved by thermally curing the curable composition according to the embodiment. When the compound represented by Chemical Formula 1, used as the polymerizable compound, thermally decomposes to reveal thiol groups, these thiol groups readily induce a thiol-ene reaction between the carbon-carbon double bonds of the (meth)acrylate groups and the thiol groups. This, in turn, promotes surface hardening of the thermosetting monolayer of the curable composition according to the embodiment, ultimately significantly reducing the reflectivity, particularly the diffuse reflectivity, of the cured layer. For example, the diffuse reflectivity of the cured layer can be reduced to 55% or less, for example, 50% to 55%.

For example, Chemical Formula 1 can be represented by Chemical Formula 1-1. When the two substituents on the benzene ring are positioned in this manner, it is more advantageous to improve optical properties and reduce reflectivity. [Chemical Formula 1-1]

In Chemical Formula 1-1, ^X1 and ^X2 are each independently an oxygen atom or a sulfur atom, ^R1 and ^R2 are each independently a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group, and ^L1 is a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C1 to C20 oxyalkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, or a combination thereof.

For example, the first polymerizable compound can be represented by Chemical Formula 1-1-1 or Chemical Formula 1-1-2, but is not necessarily limited thereto. [Chemical Formula 1-1-1] [Chemical formula 1-1-2] (Second polymerizable compound)

The curable composition according to the embodiment further includes a second polymerizable compound in addition to the first polymerizable compound. The second polymerizable compound has a different structure from the first polymerizable compound and includes a thiophene ring or a furan ring. This maximizes the effects of improving the optical properties of the curable composition and reducing the reflectivity of the curable composition.

For example, the second polymerizable compound can be represented by Chemical Formula 2. [Chemical Formula 2]

In Chemical Formula 2, ^X3 and ^X4 are each independently an oxygen atom or a sulfur atom, ^R3 is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group, ^L2 is a single bond or a substituted or unsubstituted C1 to C20 alkylene group, ^L3 is a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C1 to C20 oxyalkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, or a combination thereof, and n is an integer from 1 to 4.

For example, in Chemical Formula 2, n can be an integer equal to 1.

For example, Chemical Formula 2 can be represented by Chemical Formula 2-1. [Chemical Formula 2-1]

In Chemical Formula 2-1, ^X3 and ^X4 are each independently an oxygen atom or a sulfur atom, ^R3 is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group, ^L2 is a single bond or a substituted or unsubstituted C1 to C20 alkylene group, and ^L3 is a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C1 to C20 oxyalkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, or a combination thereof.

For example, the second polymerizable compound may include at least one selected from Chemical Formula 2-1-1 to Chemical Formula 2-1-3. However, this is merely an example, and the second polymerizable compound is not limited to the following chemical formula. However, when Chemical Formula 2 is represented by any one selected from Chemical Formula 2-1 to Chemical Formula 2-3, it is highly advantageous to simultaneously improve the optical properties of the curable composition according to the embodiment and reduce the reflectivity (diffuse reflectivity) of the curable composition. [Chemical Formula 2-1-1] [Chemical formula 2-1-2] [Chemical formula 2-1-3]

The second polymerizable compound may have a refractive index greater than or equal to 1.5 and a viscosity less than 10 centipoise.

For example, the first polymerizable compound and the second polymerizable compound may be included in a weight ratio of 1:9 to 9:1, for example, 5:5 to 9:1.

For example, the first polymerizable compound may be included in a greater amount than the second polymerizable compound.

For example, the first polymerizable compound and the second polymerizable compound may be included in a weight ratio of 6:4 to 9:1.

When the first polymerizable compound is included in an amount greater than the second polymerizable compound, for example, when the first polymerizable compound and the second polymerizable compound are included in a weight ratio of 6:4 to 9:1, both the effects of improving optical properties and reducing reflectivity can be maximized. (Third polymerizable compound)

For example, the polymerizable compound may further include a third polymerizable compound having a structure different from that of the first polymerizable compound and the second polymerizable compound.

For example, the third polymerizable compound can be represented by Chemical Formula 3. [Chemical Formula 3]

In Formula 3, ^L4 is a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, or an ether group (*-O-*), ^L5 and ^L6 are each independently a single bond or a substituted or unsubstituted C1 to C10 alkylene group, and ^R4 and ^R5 are each independently a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group.

When the curable composition according to the embodiment further includes a high-refractive/high-viscosity compound represented by Chemical Formula 1, a compound represented by Chemical Formula 2, and a compound represented by Chemical Formula 3 as polymerizable compounds, when a mixture of the compound represented by Chemical Formula 1 and the compound represented by Chemical Formula 2 is used, the effects of improving the optical properties of the curable composition and reducing the reflectivity of the curable composition can be achieved simultaneously.

For example, the compound represented by Chemical Formula 3 may have a refractive index less than 1.5 or a viscosity less than 10 centipoise. When the compound represented by Chemical Formula 3 has a refractive index greater than or equal to 1.5 and a viscosity less than 10 centipoise, it is advantageous in improving optical properties but may be disadvantageous in reducing reflectivity.

For example, the compound represented by Chemical Formula 3 can be represented by Chemical Formula 3-1, Chemical Formula 3-2, or Chemical Formula 3-3, but is not necessarily limited thereto. [Chemical Formula 3-1] [Chemical formula 3-2] [Chemical formula 3-3]

For example, in addition to the first polymerizable compound, the second polymerizable compound, and the third polymerizable compound, the polymerizable compound may further include ethylene glycol diacrylate, triethylene glycol diacrylate, 1,4-butanediol diacrylate, neopentyl glycol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, dipentaerythritol diacrylate, dipentaerythritol triacrylate, dipentaerythritol pentaacrylate, pentaerythritol hexaacrylate, bisphenol A diacrylate, trihydroxymethylpropane triacrylate, novolacepoxyacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, or a combination thereof.

In addition to the polymerizable compound, monomers commonly used in conventional thermosetting or photocurable compositions may be used. For example, the monomers may further include oxadiazolidine monomers, such as bis[1-ethyl(3-oxadiazolidine)]methyl ether.

The polymerizable compound may be included in an amount of 40% to 95% by weight, for example, 50% to 90% by weight, based on the total amount of the solvent-free curable composition. When the polymerizable compound is included within this range, a solvent-free curable composition having a viscosity sufficient for inkjetting can be prepared, and the quantum dots in the prepared solvent-free curable composition can have improved dispersibility, thereby improving optical properties.

For example, the polymerizable compound may have a molecular weight of 170 g/mol to 1,000 g/mol. When the molecular weight of the polymerizable compound is within the above range, it is advantageous for inkjetting because it does not impair the optical properties of the quantum dots and does not increase the viscosity of the composition.

In addition, when the curable composition contains a solvent, the polymerizable compound may be contained in an amount of 1 wt % to 20 wt %, 1 wt % to 15 wt %, for example, 5 wt % to 15 wt %, based on the total amount of the curable composition. When the polymerizable compound is contained within the above range, the optical properties of the quantum dots can be improved. Quantum Dots

For example, quantum dots may have a maximum fluorescence emission wavelength at about 500 nm to about 680 nm.

For example, when the curable composition according to the embodiment is a solvent-free curable composition, the quantum dots may be included in an amount of 5% to 60% by weight, for example, 10% to 60% by weight, for example, 20% to 60% by weight, for example, 30% to 50% by weight. When the quantum dots are included within the above range, high light retention and light efficiency can be achieved even after curing.

For example, when the curable composition according to the embodiment is a solvent-containing curable composition, the quantum dots may be included in an amount of 1 to 40 wt %, for example, 3 to 30 wt %, based on the total weight of the curable composition. When the quantum dots are included within this range, the light conversion efficiency is improved without compromising pattern and development properties, thereby achieving improved processability.

For example, quantum dots absorb light in the wavelength range of 360 nm to 780 nm, for example, 400 nm to 780 nm, and emit fluorescence in the wavelength range of 500 nm to 700 nm, for example, 500 nm to 580 nm, or 600 nm to 680 nm. In other words, quantum dots may have a maximum fluorescence emission wavelength (fluorescence λ _em ) at 500 nm to 680 nm.

Quantum dots can each independently have a full width at half maximum (FWHM) of 20 nm to 100 nm, for example, 20 nm to 50 nm. When quantum dots have a FWHM within this range, when used as a color material in a color filter, color reproducibility is enhanced due to high color purity.

The quantum dots can be independently organic materials, inorganic materials, or a mixture of organic and inorganic materials.

Quantum dots can each independently consist of a core and a shell surrounding the core, and the core and shell can each independently have a core, core/shell, core/first shell/second shell, alloy, alloy/shell, etc. composed of II-IV group, III-V group, etc., but are not limited to these.

For example, the core may include at least one material selected from, but not limited to, CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe, GaN, GaP, GaAs, InP, InAs, and alloys thereof. The shell surrounding the core may include at least one material selected from, but not limited to, CdSe, ZnSe, ZnS, ZnTe, CdTe, PbS, TiO, SrSe, HgSe, and alloys thereof.

In this embodiment, since global environmental concerns have greatly increased recently and restrictions on toxic materials have been strengthened, cadmium-free luminescent materials (such as InP/ZnS, InP/ZnSe/ZnS) with slightly lower quantum efficiency (quantum yield) but harmless to the environment are used to replace luminescent materials with cadmium-based cores, but are not necessarily limited to these.

In one embodiment, a quantum dot may include a core containing silver (Ag), indium (In), gallium (Ga), and sulfur (S), and a shell containing at least two (or at least three) selected from the group consisting of silver (Ag), gallium (Ga), zinc (Zn), and sulfur (S). In this case, the quantum dot may have more than one type of ligand. For example, the quantum dot may include a first ligand containing a halide, a second ligand containing an alkyl and/or alkoxyamine group, or a combination thereof, but is not limited to these.

In the case of core/shell structured quantum dots, the size (average particle size) of each quantum dot including the shell may be 1 nm to 15 nm, for example, 5 nm to 15 nm.

For example, the quantum dots may each independently include red quantum dots, green quantum dots, or a combination thereof. The red quantum dots may each independently have an average particle size of 10 nm to 15 nm. The green quantum dots may each independently have an average particle size of 5 nm to 8 nm.

On the other hand, to achieve stable dispersion of quantum dots, the curable composition according to the embodiment may further include a dispersant. The dispersant facilitates uniform dispersion of light-conversion materials, such as quantum dots, in the photosensitive resin composition and may include a non-ionic dispersant, anionic dispersant, or cationic dispersant. Specifically, the dispersant may be a polyalkylene glycol or its ester, polyoxyalkylene, polyol ester epoxy adduct, alcohol epoxy adduct, sulfonic acid ester, sulfonic acid salt, carboxylic acid ester, carboxylic acid salt, alkylamide epoxy adduct, alkylamine, etc., and may be used alone or in mixtures of two or more. The dispersant may be used in an amount of 0.1 wt % to 100 wt %, for example, 10 wt % to 20 wt %, based on the solid content of the light conversion material (eg, quantum dots).

For example, quantum dots can be surface-modified with ligands having polar groups (e.g., ligands with a high affinity for the polymerizable compound). Surface-modified quantum dots, as described above, make it very easy to prepare high-concentration or highly concentrated quantum dot dispersions (with enhanced dispersibility of the quantum dots in the polymerizable compound). This can significantly improve photoefficiency and is particularly advantageous in the implementation of solvent-free curable compositions.

For example, a ligand having a polar group may have a structure that has a high affinity for the chemical structure of the polymerizable compound.

For example, the ligand having a polar group can be represented by any of the compounds represented by Chemical Formula A to Chemical Formula Q, but is not necessarily limited thereto. [Chemical Formula A] [Chemical Formula B] [Chemical formula C] [Chemical formula D]

In Chemical Formula D, m1 is an integer from 0 to 10. [Chemical Formula E] [Chemical formula F] [Chemical formula G] [Chemical formula H] [Chemical Formula I] [Chemical formula J] [Chemical formula K] [Chemical formula L] [Chemical formula M] [Chemical formula N] [Chemical formula O] [Chemical formula P] [Chemical formula Q]

When a ligand is used, the surface modification of quantum dots is easier, and when the quantum dots surface-modified with the ligand are added to the polymerizable compound and stirred, an extremely transparent dispersion is obtained, indicating that the surface modification of the quantum dots is highly successful.

The curable composition according to the embodiment may further include a light diffuser.

For example, the light diffuser may include barium sulfate (BaSO ₄ ), calcium carbonate (CaCO ₃ ), titanium dioxide (TiO ₂ ), zirconium oxide (ZrO ₂ ), or a combination thereof.

The light diffuser reflects light that is not absorbed by the quantum dots and allows the quantum dots to reabsorb the reflected light. In other words, the light diffuser increases the amount of light absorbed by the quantum dots and improves the light conversion efficiency of the curable composition.

The light diffuser may have an average particle size ( _D50 ) of 150 nm to 250 nm, specifically 180 nm to 230 nm. When the average particle size of the light diffuser is within this range, it may have a better light diffusion effect and increase light conversion efficiency.

The light diffuser may be included in an amount of 1 to 20 wt %, for example, 2 to 15 wt %, and for example, 3 to 10 wt %, based on the total amount of the curable composition. If the light diffuser is included in an amount of less than 1 wt %, it is difficult to expect the effect of improving the light conversion efficiency by using the light diffuser, while if the light diffuser is included in an amount of more than 20 wt %, quantum dot deposition problems may occur. Polymerization initiator

The curable composition according to the embodiment may further include a polymerization initiator, such as a photopolymerization initiator, a thermal polymerization initiator, or a combination thereof.

The polymerization initiator may be an initiator commonly used in photosensitive resin compositions, and may include, for example, acetophenone-based compounds, benzophenone-based compounds, thioxanthone-based compounds, benzoin-based compounds, triazine-based compounds, oxime-based compounds, and aminoketone-based compounds, but is not necessarily limited thereto.

Examples of acetophenone compounds include 2,2'-diethoxyacetophenone, 2,2'-dibutoxyacetophenone, 2-hydroxy-2-methylpropiophenone, 4-tert-butyltrichloroacetophenone, 4-tert-butyldichloroacetophenone, 4-chloroacetophenone, 2,2'-dichloro-4-phenoxyacetophenone, 2-methyl-1-(4-(methylthio)phenyl)-2-morpholinopropan-1-one, and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one.

Examples of benzophenone compounds include benzophenone, benzoyl benzoate, benzoyl methyl benzoate, 4-phenylbenzophenone, hydroxybenzophenone, acrylated benzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, 4,4'-dimethylaminobenzophenone, 4,4'-dichlorobenzophenone, and 3,3'-dimethyl-2-methoxybenzophenone.

Examples of the thiothione compounds include thiothione, 2-methylthiothione, isopropylthiothione, 2,4-diethylthiothione, 2,4-diisopropylthiothione, and 2-chlorothiothione.

Examples of benzoin compounds include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and benzyl dimethyl ketal.

Examples of triazine compounds include 2,4,6-trichloro-s-triazine, 2-phenyl-4,6-bis(trichloromethyl)-s-triazine, 2-(3',4'-dimethoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4'-methoxynaphthyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(p-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(p-tolyl)-4,6-bis(trichloromethyl)- s-triazine, 2-biphenyl-4,6-bis(trichloromethyl)-s-triazine, bis(trichloromethyl)-6-phenylvinyl-s-triazine, 2-(naphthol-1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-methoxynaphthol-1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2-4-bis(trichloromethyl)-6-piperonyl-s-triazine, 2-4-bis(trichloromethyl)-6-(4-methoxyphenylvinyl)-s-triazine, etc.

Examples of oxime compounds include O-acyl oxime compounds, 2-(O-benzoyloxime)-1-[4-(phenylthio)phenyl]-1,2-octanedione, 1-(O-acetyloxime)-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone, and O-ethoxycarbonyl-α-oxyamino-1-phenylpropan-1-one. Specific examples of O-acyl oxime compounds include 1,2-octanedione, 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one, 1-(4-phenylthiophenyl)-butane-1,2-dione-2-oxime-O-benzoate, 1-(4-phenylthiophenyl)-octane-1,2-dione-2-oxime-O-benzoate, 1-(4-phenylthiophenyl)-octane-1,2-dione-2-oxime-O-benzoate, 1-(4-phenylthiophenyl)-octan-1-one oxime-O-acetate, and 1-(4-phenylthiophenyl)-butan-1-one oxime-O-acetate.

Examples of aminoketone compounds include 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1-.

In addition to the aforementioned compounds, the photopolymerization initiator may further include carbazole compounds, diketone compounds, cobalt borate compounds, diazo compounds, imidazole compounds, biimidazole compounds, and the like.

The photopolymerization initiator can be used together with a photosensitizer that can induce a chemical reaction by absorbing light and become excited and subsequently transfer its energy.

Examples of the photosensitizer include tetraethylene glycol di-3-butyl propionate, pentaerythritol tetra-3-butyl propionate, and dipentaerythritol tetra-3-butyl propionate.

Examples of thermal polymerization initiators include peroxides, specifically benzoyl peroxide, dibenzoyl peroxide, lauryl peroxide, dilauryl peroxide, di-tert-butyl peroxide, cyclohexane peroxide, methyl ethyl ketone peroxide, hydroperoxides (e.g., tert-butyl hydroperoxide, cumene hydroperoxide), dicyclohexyl peroxydicarbonate, 2,2-azobis(isobutyronitrile), tert-butyl perbenzoate, and the like, such as 2,2'-azobis-2-methylpropionitrile, but are not necessarily limited thereto, and any of those known in the art may be used.

The polymerization initiator may be included in an amount of 0.1 to 5 wt %, for example, 1 to 4 wt %, based on the total amount of the curable composition. When the polymerization initiator is included within this range, excellent reliability can be achieved due to sufficient curing during exposure or heat curing, and degradation of transmittance can be prevented due to the non-reactive initiator, thereby preventing degradation of the optical properties of the quantum dots. Binder resin

The curable composition according to the embodiment may further include a binder resin.

The adhesive resin may include an acrylic resin, a cardo resin, an epoxy resin, or a combination thereof.

The acrylic resin may be a copolymer of a first ethylenically unsaturated monomer and a second ethylenically unsaturated monomer copolymerizable therewith, and may be a resin comprising at least one acrylic repeating unit.

Specific examples of acrylic adhesive resins include polybenzyl methacrylate, (meth)acrylic acid/benzyl methacrylate copolymer, (meth)acrylic acid/benzyl methacrylate/styrene copolymer, (meth)acrylic acid/benzyl methacrylate/2-hydroxyethyl methacrylate copolymer, (meth)acrylic acid/benzyl methacrylate/styrene/2-hydroxyethyl methacrylate copolymer, etc., but are not limited thereto, and these may be used alone or in the form of a mixture of two or more.

The weight average molecular weight of the acrylic adhesive resin may be 5,000 g/mol to 15,000 g/mol. When the acrylic adhesive resin has a weight average molecular weight within this range, it exhibits improved contact with the substrate, physical and chemical properties, and suitable viscosity.

The acrylic resin may have an acid value of 80 mgKOH/g to 130 mgKOH/g. When the acrylic resin has an acid value within this range, the pixel pattern may have excellent resolution.

Cardo-based resins can be used in conventional curable resin (or photosensitive resin) compositions and can be used, for example, as disclosed in Korean Patent Application No. 10-2018-0067243, but are not limited thereto.

Cardo-based resins can be prepared, for example, by mixing at least two of the following compounds: a fluorene-containing compound, such as 9,9-bis(4-epoxyethylmethoxyphenyl)fluorene; an acid anhydride compound, such as pyromellitic dianhydride, naphthalenetetracarboxylic dianhydride, biphenyltetracarboxylic dianhydride, benzophenonetetracarboxylic dianhydride, pyromellitic dianhydride, cyclobutanetetracarboxylic dianhydride, perylenetetracarboxylic dianhydride, tetrahydrofurantetracarboxylic dianhydride, and tetrahydrophthalic anhydride. ; glycol compounds, such as ethylene glycol, propylene glycol, and polyethylene glycol; alcohol compounds, such as methanol, ethanol, propanol, n-butanol, cyclohexanol, and benzyl alcohol; solvent compounds, such as propylene glycol, ethyl methyl acetate, and N-methylpyrrolidone; phosphorus compounds, such as triphenylphosphine; and amine or ammonium salt compounds, such as tetramethylammonium chloride, tetraethylammonium bromide, benzyldiethylamine, triethylamine, tributylamine, or benzyltriethylammonium chloride.

The weight average molecular weight of the cardo-based binder resin can be 500 g/mol to 50,000 g/mol, for example, 1,000 g/mol to 30,000 g/mol. When the weight average molecular weight of the cardo-based binder resin is within this range, satisfactory patterns can be formed without residual groups during the production of the cured layer and without loss of film thickness during development of the solvent-based curable composition.

When the binder resin is a cardo-based resin, the developability of the curable composition containing the binder resin, specifically the photosensitive resin composition, is improved, and the sensitivity during photocuring is good, resulting in improved fine pattern formation properties.

Epoxy resins can be monomers or oligomers that can be polymerized by heating and can include compounds having carbon-carbon unsaturated bonds and carbon-carbon cyclic bonds.

Epoxy resins may include, but are not limited to, bisphenol A epoxy resins, bisphenol F epoxy resins, phenol novolac epoxy resins, epoxide aliphatic epoxy resins, and aliphatic polyglycidyl ethers.

Its currently available products may include: bisphenol epoxy resins, such as YX4000, YX4000H, YL6121H, YL6640, or YL6677 from Yuka Shell Epoxy Co., Ltd.; cresol novolac-type epoxy resins, such as EOCN-102, EOCN-103S, EOCN-104S, EOCN-1020, EOCN-1025, and EOCN-1027 from Nippon Kayaku Co., Ltd., and EPIKOTE 180S75 from Yuka Shell Epoxy Co., Ltd.; bisphenol A epoxy resins, such as EPIKOTE from Yuka Shell Epoxy Co., Ltd. 1001, 1002, 1003, 1004, 1007, 1009, 1010, and 828; bisphenol F-type epoxy resins, such as EPIKOTE 807 and 834 from Uka Shell Epoxy Co., Ltd.; phenol novolac-type epoxy resins, such as EPIKOTE 152, 154, and 157H65 from Uka Shell Epoxy Co., Ltd. and EPPN 201 and 202 from Nippon Kayaku Co., Ltd.; other cyclic aliphatic epoxy resins, such as those from CIBA-GEIGY A.G.), ERL-4234, ERL-4299, ERL-4221, and ERL-4206 from U.C.C., Shodyne 509 from Showa Denko K.K., ARALDITE CY-182, CY-192, and CY-184 from Ciba-Geigy A.G., Epichron 200 and 400 from Dainippon Ink and Chemicals Inc., EPIKOTE 871, 872, and EP1032H60 from Yuxiang Shell Epoxy Co., Ltd., and Celanese Coatings Co., Ltd. Ltd.'s ED-5661 and ED-5662; aliphatic polyglycidyl ethers, such as EPIKOTE 190P and 191P from Yuxiangkai Epoxy Co., Ltd., Epolite 100MF from Kyoesha Yushi Co., Ltd., and Epiol TMP from Nippon Yushi Co., Ltd.

For example, when the curable composition according to the embodiment is a solvent-free curable composition, the binder resin content can be 0.5% to 10% by weight, for example, 1% to 5% by weight, based on the total weight of the curable composition. In this case, the heat resistance and chemical resistance of the solvent-free curable composition can be improved, and the storage stability of the composition can also be enhanced.

For example, when the curable composition according to the embodiment is a curable composition containing a solvent, the binder resin may be contained in an amount of 1 wt % to 30 wt %, for example, 3 wt % to 20 wt %, based on the total amount of the curable composition. In this case, pattern characteristics, heat resistance, and chemical resistance can be improved. Other additives

To improve the stability and dispersibility of quantum dots, the curable composition according to the embodiment may further include a polymerization inhibitor.

The polymerization inhibitor may include, but is not limited to, a hydroquinone compound, a catechol compound, or a combination thereof. If the curable composition according to the embodiment further includes a hydroquinone compound, a catechol compound, or a combination thereof, room temperature crosslinking can be prevented during exposure after application of the curable composition.

For example, the hydroquinone compound, catechol compound, or a combination thereof may be hydroquinone, methylhydroquinone, methoxyhydroquinone, t-butylhydroquinone, 2,5-di-t-butylhydroquinone, 2,5-bis(1,1-dimethylbutyl)hydroquinone, 2,5-bis(1,1,3,3-tetramethylbutyl)hydroquinone, catechol, t-butylcatechol, 4-methoxycatechol, gallol, 2,6-di-t-butyl-4-methylphenol, 2-naphthol, tris(N-hydroxy-N-nitrosophenylamino-O,O')aluminum, or a combination thereof, but is not necessarily limited thereto.

The hydroquinone compound, catechol compound, or combination thereof can be used in the form of a dispersion. A polymerization inhibitor in the form of a dispersion can be included in an amount of 0.001 to 3% by weight, for example, 0.01 to 2% by weight, based on the total weight of the curable composition. Including the polymerization inhibitor within this range can address aging issues at room temperature and prevent sensitivity degradation and surface delamination.

In addition, the curable composition according to the embodiment may further include: malonic acid; 3-amino-1,2-propanediol; a silane coupling agent; a leveling agent; a fluorine-based surfactant; or a combination thereof to improve heat resistance and reliability.

For example, the curable composition according to the embodiment may further include a silane-based coupling agent having a reactive substituent such as a vinyl group, a carboxyl group, a methacryl group, an isocyanate group, or an epoxy group to improve the close contact property with the substrate.

Examples of silane coupling agents include trimethoxysilylbenzoic acid, γ-methacryloyloxypropyltrimethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, γ-isocyanatepropyltriethoxysilane, γ-glycidyloxypropyltrimethoxysilane, and β-epoxyhexylethyltrimethoxysilane. These coupling agents may be used alone or as a mixture of two or more.

The silane coupling agent may be used in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the curable composition. When the silane coupling agent is included in an amount within the above range, close contact properties, storage capacity, etc. are improved.

In addition, the curable composition may further contain a surfactant (e.g., a fluorine-based surfactant) as needed to improve coating properties and inhibit the generation of spots, that is, to improve leveling performance.

Fluorine-based surfactants can have a low weight-average molecular weight of 4,000 to 10,000 g/mol, specifically 6,000 to 10,000 g/mol. Furthermore, they can have a surface tension of 18 to 23 mN/m (measured in a 0.1% polyethylene glycol monomethylether acetate (PGMEA) solution). Fluorine-based surfactants with weight-average molecular weights and surface tensions within these ranges can further improve leveling performance and offer superior properties for narrow gap coating applications at high speeds. This is because they can prevent spot formation and suppress vapor generation during high-speed coating, resulting in fewer film defects.

Examples of fluorine-based surfactants include BM- ^1000® and BM- ^1100® (BM Chemie Inc.); MEGAFACE F ^142D® , F ^172® , F 173® ^, and F ^183® (Dainippon Ink Kagaku Kogyo Co., Ltd.); FULORAD FC- ^135® , FULORAD FC- ^170C® , FULORAD FC- ^430® , and FULORAD FC- ^431® (Sumitomo 3M Co., Ltd.); SURFLON S- ^112® , S- ^113® , S- ^131® , and S-141® (Sumitomo 3M Co., Ltd.). ^® and Saffron S-145 ^® (ASAHI Glass Co., Ltd.); and SH-28PA ^® , SH-190 ® , SH-193 ^® , SZ-6032 ^® , and SF-8428 ^® , etc. (Toray Silicone Co., Ltd.); and DIC Co., Ltd.'s F-482, F-484, F-478, F-554, etc.

In addition to the fluorine-based surfactant, the curable composition according to the embodiment may also include a silicone-based surfactant. Specific examples of silicone-based surfactants include, but are not limited to, TSF400, TSF401, TSF410, and TSF4440 from Toshiba Silicone Co., Ltd.

The surfactant may be included in an amount of 0.01 to 5 parts by weight, for example 0.1 to 2 parts by weight, based on 100 parts by weight of the curable composition. If the surfactant is included in an amount within the above range, less foreign matter will be generated in the sprayed composition.

In addition, the curable composition according to the embodiment may further contain other additives such as antioxidants, stabilizers, etc. in predetermined amounts unless the properties are deteriorated.

Meanwhile, the curable composition according to the embodiment may further include a solvent.

The solvent may include, for example, alcohols such as methanol, ethanol, etc.; glycol ethers such as ethylene glycol methyl ether, ethylene glycol ethyl ether, propylene glycol methyl ether, etc.; solvent acetates such as methyl solvent acetate, ethyl solvent acetate, diethyl solvent acetate, etc.; carbitols such as methyl ethyl carbitol, diethyl carbitol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, etc.; propylene glycol alkyl ether acetates such as propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, etc.; ketones such as methyl ethyl ketone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone, methyl-n-propyl ketone, methyl-n-butyl ketone , methyl-n-amyl ketone, 2-heptanone, etc.; saturated aliphatic monocarboxylic acid alkyl esters, such as ethyl acetate, n-butyl acetate, isobutyl acetate, etc.; lactic acid esters, such as methyl lactate, ethyl lactate, etc.; hydroxyacetic acid alkyl esters, such as methyl hydroxyacetate, ethyl hydroxyacetate, butyl hydroxyacetate, etc.; acetic acid alkoxyalkyl esters, such as methyl methoxyacetate, ethyl methoxyacetate, butyl methoxyacetate, methyl ethoxyacetate, ethyl ethoxyacetate, etc.; 3-hydroxypropionic acid alkyl esters, such as methyl 3-hydroxypropionic acid, ethyl 3-hydroxypropionic acid, etc.; 3-alkoxypropionic acid alkyl esters, such as methyl 3-methoxypropionic acid, ethyl 3-methoxypropionic acid, 3-ethoxypropionic acid ethyl 2-methoxypropionate, ethyl 2-methoxypropionate, ethyl 2-ethoxypropionate, methyl 2-ethoxypropionate, etc.; alkyl 2-hydroxypropionates, such as methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, methyl 3-ethoxypropionate, etc.; alkyl 2-alkoxypropionates, such as methyl 2-methoxypropionate, ethyl 2-methoxypropionate, ethyl 2-ethoxypropionate, methyl 2-ethoxypropionate, etc.; alkyl 2-hydroxy-2-methylpropionates, such as methyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, etc.; alkyl 2-alkoxy-2-methylpropionates, such as methyl 2-methoxy-2-methylpropionate, ethyl 2-ethoxy-2-methylpropionate, etc.; esters, such as 2-hydroxyethyl propionate, propyl propionate, etc. Examples of the ester include 2-hydroxy-2-methylethyl butyrate, 2-hydroxy-3-methylmethyl butyrate, and ketoesters such as ethyl pyruvate. Examples include N-methylformamide, N,N-dimethylformamide, N-methylformaniline, N-methylacetamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, benzyl ethyl ether, dihexyl ether, acetylacetone, isophorone, hexanoic acid, octanoic acid, 1-octanol, 1-nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, γ-butyrolactone, ethyl carbonate, propyl carbonate, and phenyl cellosolve acetate, but are not limited thereto.

For example, the solvent may be glycol ethers, such as ethylene glycol monoethyl ether, ethylene glycol methyl ethyl ether, etc.; ethylene glycol alkyl ether acetates, such as ethyl solvent acetate, etc.; esters, such as 2-hydroxyethyl propionate, etc.; carbitols, such as diethylene glycol monomethyl ether, etc.; propylene glycol alkyl ether acetates, such as propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, etc.; alcohols, such as ethanol, etc., or combinations thereof.

For example, the solvent can be a polar solvent including propylene glycol monomethyl ether acetate, dipropylene glycol methyl ether acetate, ethanol, ethylene glycol dimethyl ether, ethylene glycol methyl ethyl ether, diethylene glycol dimethyl ether, 2-butoxyethanol, N-methylpyrrolidine, N-ethylpyrrolidine, propylene carbonate, γ-butyrolactone, or a combination thereof.

The solvent may be included in an amount of 40% to 80% by weight, for example, 45% to 80% by weight, based on the total amount of the curable composition. When the solvent is within this range, the solvent-based curable composition has an appropriate viscosity and thus has excellent coating properties when applied to a large area by spin coating and slit coating.

Another embodiment provides a cured layer manufactured using the curable composition and a display device including the cured layer. In this case, the cured layer may have a diffuse reflectivity of 50% to 55% as described above.

One method of producing a cured layer may include: applying the curable composition described above to a substrate using an inkjet printing method to form a pattern (S1); and curing the pattern (S2). (S1) Forming Pattern

It is desirable to apply the curable composition to a thickness of 0.5 to 20 microns on the substrate using an inkjet printing method. The inkjet printing method can form a pattern by having each nozzle spray a single color and repeating the spraying a number of times equal to the desired number of colors. However, the pattern can also be formed by having each inkjet nozzle spray the desired number of colors simultaneously, thereby reducing the manufacturing process. (S2) Curing

The resulting pattern is cured to obtain pixels. Herein, the curing method may be a thermal curing or photocuring process. The thermal curing process may be performed at a temperature greater than or equal to 100°C, preferably within a range of 100°C to 300°C, and more preferably within a range of 160°C to 250°C. The photocuring process may include irradiation with actinic radiation, such as ultraviolet (UV) radiation with a wavelength of 190 to 450 nm, for example, 200 to 500 nm. Irradiation is performed using a light source such as a low-pressure, high-pressure, or ultrahigh-pressure mercury lamp, a metal halogen lamp, or an argon laser. X-rays, electron beams, and the like may also be used as needed.

Other methods of producing a cured layer may include using a curable composition to produce a cured layer by the following lithographic method. (1) Coating and film formation

The curable composition is applied to a substrate subjected to a predetermined pretreatment to a desired thickness, for example, a thickness in the range of 2 μm to 10 μm, using a spin coating method, a slit coating method, a roller coating method, a screen printing method, a coater method, or the like. The coated substrate is then heated at a temperature of 70° C. to 90° C. for 1 minute to 10 minutes to remove the solvent and form a film. (2) Exposure

After placing a mask having a predetermined shape, the resulting film is irradiated with actinic radiation, such as UV radiation with a wavelength of 190 to 450 nm, or 200 to 500 nm, to form the desired pattern. Irradiation is performed using light sources such as low-pressure, high-pressure, or ultra-high-pressure mercury lamps, metal halogen lamps, or argon lasers. X-rays, electron beams, and the like may also be used as needed.

When a high-pressure mercury lamp is used, the exposure process uses a light dose of, for example, 500 mJ/cm² or less (using a 365 nm sensor). However, the light dose may vary depending on the type of each component of the curable composition, its combination ratio, and the dry film thickness. (3) Development

After the exposure process, the exposed film is developed using an alkaline aqueous solution by dissolving and removing the excess areas other than the exposed areas to form an image pattern. In other words, when developing using an alkaline developing solution, the unexposed areas are dissolved and an image color filter pattern is formed. (4) Post-processing

The developed image pattern can be cured by heating it again or irradiating it with actinic rays, etc., to achieve excellent qualities such as heat resistance, light resistance, close contact properties, crack resistance, chemical resistance, high strength, and storage stability.

Hereinafter, the present invention will be described in more detail with reference to examples. However, these examples should not be construed as limiting the scope of the present invention in any sense. Preparation of polymerizable compounds Preparation Example 1

20 g of 4-(methylthio)benzenethiol was thoroughly dissolved in 200 ml of dimethylformamide (DMF). Subsequently, 26.5 g _{of K₂CO₃} and 17.59 g of 2-bromoethanol were added sequentially, and the reaction was stirred at room temperature (23°C) for 12 hours to complete. The resulting product was diluted with 200 ml of ethyl acetate and extracted three times with 1N aqueous HCl. The organic layer extracted with _MgSO₄ was stirred for 5 minutes and filtered, and the filtrate was concentrated. The resulting product was purified by column, concentrated, and dried under vacuum.

The dried intermediate was thoroughly dissolved in 150 ml of dichloromethane and stirred at 0°C for 10 minutes. 8.87 g of triethylamine was added, followed by stirring for an additional 10 minutes. 9.92 g of acryloyl chloride was slowly added dropwise at 0°C, followed by stirring for 30 minutes to complete the reaction. The reaction solution was extracted with 150 ml of 1N aqueous HCl and then 150 ml of water. The separated organic layer, to which _MgSO₄ had been added, was stirred and filtered, and the resulting filtrate was concentrated. The resulting product was column purified, concentrated, and vacuum dried to prepare the compound represented by Chemical Formula 1-1-1 (refractive index: 1.5607, viscosity: 21 centipoise). [Chemical formula 1-1-1] Preparation Example 2

20 g of 4-(methylthio)phenol was thoroughly dissolved in 200 ml of DMF. Subsequently, 29.57 g of _K₂CO₃ and 19.61 g of 2-bromoethanol were added sequentially, and the mixture was stirred at room temperature for 12 hours to complete the reaction. The resulting product was diluted with 200 ml of ethyl _acetate and extracted three times with 1N aqueous HCl. The separated organic layer, to which _MgSO₄ had been added, was stirred for 5 minutes and filtered, and the resulting filtrate was concentrated. The resulting product was column purified, concentrated, and vacuum dried.

14.63 g of the dried intermediate was thoroughly dissolved in 150 ml of dichloromethane and stirred at 0°C for 10 minutes. 9.64 g of triethylamine was added and stirred for an additional 10 minutes. 10.78 g of acryloyl chloride was slowly added dropwise at 0°C and stirred for 30 minutes to complete the reaction. The reaction solution was extracted with 150 ml of 1N aqueous HCl and then 150 ml of water. The separated organic layer, to which _MgSO₄ had been added, was stirred and filtered, and the resulting filtrate was concentrated. The resulting product was column purified, concentrated, and vacuum dried to obtain the compound represented by Chemical Formula 1-1-2 (refractive index: 1.5995, viscosity: 17 centipoise). [Chemical Formula 1-1-2] Preparation Example 3

18.2 g of 2-thiophenethiol was thoroughly dissolved in 200 ml of DMF. 32.47 g _{of K₂CO₃} and 21.53 g of 2-bromoethanol were added sequentially, and the mixture was stirred at room temperature for 12 hours to complete the reaction. The resulting product was diluted with 200 ml of ethyl acetate and extracted three times with 1N aqueous HCl. The separated organic layer, to which _MgSO₄ had been added, was stirred for 5 minutes and filtered, and the resulting filtrate was concentrated. The resulting product was column purified, concentrated, and vacuum dried.

15 g of the dried intermediate was thoroughly dissolved in 150 ml of dichloromethane and stirred at 0°C for 10 minutes. Subsequently, 11.37 g of triethylamine was added and stirred for an additional 10 minutes. 12.71 g of acryloyl chloride was slowly added dropwise at 0°C and stirred for 30 minutes to complete the reaction. The reaction solution was extracted with 200 ml of 1N aqueous HCl and then 200 ml of water. The separated organic layer, to which _MgSO₄ had been added, was stirred and filtered, and the resulting filtrate was concentrated. The resulting product was column purified, concentrated, and vacuum dried to obtain the compound represented by Chemical Formula 2-1-1 (refractive index: 1.5619, viscosity: 7.2 centipoise). [Chemical Formula 2-1-1] Preparation Example 4

20 g of 2-thiophenemethylthiol was thoroughly dissolved in 200 ml of DMF. 31.84 g _{of K₂CO₃} and 21.11 g of 2-bromoethanol were added sequentially, and the mixture was stirred at room temperature for 12 hours to complete the reaction. The resulting product was diluted with 200 ml of ethyl acetate and extracted three times with 1N aqueous HCl. The resulting organic layer, to which _MgSO₄ had been added, was stirred for 5 minutes and filtered, and the resulting filtrate was concentrated. The resulting product was column purified, concentrated, and vacuum dried.

15 g of the dried intermediate was thoroughly dissolved in 150 ml of dichloromethane and stirred at 0°C for 10 minutes. 10.45 g of triethylamine was added, followed by stirring for an additional 10 minutes. 11.69 g of acryloyl chloride was slowly added dropwise at 0°C, followed by stirring for 30 minutes to complete the reaction. The reaction solution was extracted with 200 ml of 1N aqueous HCl and then 200 ml of water. The separated organic layer, to which _MgSO₄ had been added, was stirred and filtered, and the resulting filtrate was concentrated. The resulting product was column purified, concentrated, and vacuum dried to obtain the compound represented by Chemical Formula 2-1-2 (refractive index: 1.5410, viscosity: 8.3 centipoise). [Chemical Formula 2-1-2] Preparation Example 5

20 g of 2-thiophene methanol was thoroughly dissolved in 200 ml of DMF. 36.32 g _{of K₂CO₃} and 24.08 g of 2-bromoethanol were added sequentially, and the mixture was stirred at room temperature for 12 hours to complete the reaction. The resulting product was diluted with 200 ml of ethyl acetate and extracted three times with 1N aqueous HCl. The separated organic layer, to which _MgSO₄ had been added, was stirred for 5 minutes and filtered, and the resulting filtrate was concentrated. The resulting product was column purified, concentrated, and vacuum dried.

15 g of the dried intermediate was thoroughly dissolved in 150 ml of dichloromethane and stirred at 0°C for 10 minutes. 11.51 g of triethylamine was added and stirred for an additional 10 minutes. 12.87 g of acryloyl chloride was slowly added dropwise at 0°C and stirred for 30 minutes to complete the reaction. The reaction solution was extracted with 200 ml of 1N aqueous HCl and then 200 ml of water. The separated organic layer, to which _MgSO₄ had been added, was stirred and filtered, and the resulting filtrate was concentrated. The resulting product was column purified, concentrated, and vacuum dried to obtain the compound represented by Chemical Formula 2-1-3 (refractive index: 1.5170, viscosity: 9.8 centipoise). [Chemical Formula 2-1-3] Preparation Example 6

20 g of 1,3,4-thiadiazole-2,5-dithiol was thoroughly dissolved in 200 ml of DMF. 55.20 g of _K₂CO₃ and 36.6 g of 2-bromoethanol were added sequentially, and the mixture was stirred at room temperature for 12 hours to complete the reaction. The resulting product was diluted with 200 ml of ethyl _acetate and extracted three times with 1N aqueous HCl. The separated organic layer, to which _MgSO₄ had been added, was stirred for 5 minutes and filtered, and the resulting filtrate was concentrated. The resulting product was column purified, concentrated, and vacuum dried.

15 g of the dried intermediate was thoroughly dissolved in 150 ml of dichloromethane and stirred at 0°C for 10 minutes. 15.41 g of triethylamine was added, followed by stirring for an additional 10 minutes. 12.64 g of acryloyl chloride was slowly added dropwise at 0°C, followed by stirring for 30 minutes to complete the reaction. The reaction solution was extracted with 200 ml of 1N aqueous HCl and then 200 ml of water. The separated organic layer, to which _MgSO₄ had been added, was stirred and filtered, and the resulting filtrate was concentrated. The resulting product was column purified, concentrated, and vacuum dried to obtain a compound represented by Chemical Formula X (refractive index: 1.5680, viscosity: 58.3 centipoise). [Chemical Formula X] Preparation of surface modified quantum dot dispersion Preparation Example 7

After placing a magnetic bar in a three-neck round-bottom flask, a green quantum dot dispersion solution (InP/ZnSe/ZnS, Hansol Chemical; quantum dot solid content 23 wt%) was added. Subsequently, a compound represented by the chemical formula Q (ligand) was added and stirred at 80°C under a nitrogen atmosphere. Upon completion of the reaction, the solution was cooled to room temperature (23°C) and then added to cyclohexane to capture the precipitate. The precipitate was separated from the cyclohexane by centrifugation and then dried in a vacuum oven for 24 hours to obtain surface-modified quantum dots.

The surface-modified green quantum dots were stirred with a polymerizable compound for 12 hours to obtain a surface-modified quantum dot dispersion (QD solid content: 23 wt%).

(*Synthesis of the compound represented by the chemical formula Q: 100 g of PH-4 (Hannong Chemicals Inc.) was placed in a 2-neck round-bottom flask and then fully dissolved in 300 ml of THF. Then, 15.4 g of NaOH and 100 ml of water were added thereto at 0°C and then fully dissolved until a clear solution was obtained. A solution prepared by dissolving 73 g of p-toluenesulfonyl chloride in 100 ml of THF was slowly poured thereinto at 0°C. The pouring was carried out for 1 hour, and then the obtained mixture was stirred at room temperature for 12 hours. When the reaction was completed, an excess of dichloromethane was added thereto, and then stirring was performed, and NaHCO was added thereto. ₃ saturated solution for extraction, titration and water removal. After removing the solvent, the residue was dried in a drying oven for 24 hours. 50 g of the dried product was added to a 2-neck round-bottom flask and stirred thoroughly with 300 ml of ethanol. Subsequently, 27 g of thiourea was added and dispersed therein, and then refluxed at 80°C for 12 hours. Subsequently, the mixture was injected into the mixture. An aqueous solution prepared by dissolving 4.4 g of NaOH in 20 ml of water was stirred for 5 hours, and an excess of dichloromethane was added. Then, an aqueous hydrochloric acid solution was added while stirring, and extraction, titration, water removal, and solvent removal were performed in this order. The solution was then dried in a vacuum oven for 24 hours to obtain the compound represented by Chemical Formula Q. (Chemical Formula Q) (Preparation of Curable Composition) Examples 1 to 8 and Comparative Examples 1 and 2

The curable compositions of Examples 1 to 8 and Comparative Examples 1 and 2 were prepared using the following components, such that the compositions were as shown in Tables 1 and 2.

Specifically, a quantum dot dispersion was weighed and diluted by mixing with a polymerizable compound. A polymerization inhibitor was added, and the mixture was stirred for 5 minutes. A photoinitiator and a photodiffuser were then added. The resulting composition was then stirred for 1 hour to prepare a curable composition. (A) Quantum Dot Preparation: Surface-modified green quantum dot dispersion prepared in Preparation Example 7. (B) Polymerizable compound (B-1) Compound of Preparation Example 1 (B-2) Compound of Preparation Example 2 (B-3) Compound of Preparation Example 3 (B-4) Compound of Preparation Example 4 (B-5) Compound of Preparation Example 5 (B-6) Compound of Preparation Example 6 (B-7) Compound represented by Chemical Formula 4-2 (refractive index: 1.455, viscosity: 6.1 cps) (Hannon Chemical Co., Ltd., HD002S) [Chemical Formula 3-2] (C) Photopolymerization initiator: TPO-L (Polynetron Co., Ltd.) (D) Photodiffuser: Titanium dioxide dispersion ( _TiO2 solid content: 20 wt%, average particle size: 200 nm, Dito Technology Co., Ltd.) (E) Polymerization inhibitor: Methylhydroquinone (TOKYO CHEMICAL) (Table 1) (Unit: wt%) Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Comparative example 1 Comparative example 2 (A) Quantum dot dispersion 38 38 38 38 38 38 38 38 41 38 (B) Polymerizable compound B-1 8.24 - - - - - - - - - B-2 - 8.24 - - - - - - - - B-3 - - 8.24 16.49 24.73 - - - - - B-4 - - - - 16.49 - - - - B-5 - - - - - - 16.49 - - - B-6 - - - - - - - 8.24 - - B-7 46.71 46.71 46.71 38.46 30.22 38.46 38.46 46.71 51.95 54.95 (C) Photopolymerization initiator 3 3 3 3 3 3 3 3 3 3 (D) Light diffusers 4 4 4 4 4 4 4 4 4 4 (E) Polymerization inhibitor 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Total 100 100 100 100 100 100 100 100 100 100 Evaluation: Evaluation of optical properties and diffuse reflectivity of curable compositions

The quantum efficiency (EQE) after exposure and the diffuse reflectance (SCE) after curing of each of the curable compositions according to Examples 1 to 8 and Comparative Examples 1 and 2 were measured using a spectrometer (CM-3600A, Konica Minolta, Inc.), and the results are shown in Table 2. (Table 2) Quantum efficiency after exposure (%) Diffuse reflectivity after curing (%) Example 1 30.5 53.6 Example 2 31.5 51.9 Example 3 30.7 53.5 Example 4 31.3 52.7 Example 5 32.0 51.2 Example 6 31.0 53.0 Example 7 30.7 53.4 Example 8 29.8 54.9 Comparative example 1 29.7 57.8 Comparative example 2 29.5 56.0

Referring to Table 2, compared to the curable compositions of Comparative Examples 1 and 2, the curable compositions of Examples 1 to 8 exhibited improved optical properties due to high quantum efficiency after exposure, and at the same time, reduced reflectivity effects due to low diffuse reflectivity after curing.

Although the present invention has been described in conjunction with what are presently considered to be practical exemplary embodiments, it should be understood that the present invention is not limited to the disclosed embodiments, but rather is intended to cover various modifications and equivalent arrangements within the spirit and scope of the appended patent applications. Therefore, the above embodiments should be understood as illustrative and should not be construed as limiting the present invention in any way.

without

without

Claims (15)

A curable composition comprising: (A) surface-modified quantum dots; and (B) a polymerizable compound, wherein the polymerizable compound comprises: a first polymerizable compound having a refractive index greater than or equal to 1.5 and a viscosity greater than or equal to 10 centipoise and including a benzene ring, and a second polymerizable compound having a structure different from that of the first polymerizable compound and including a thiophene ring or a furan ring, wherein the first polymerizable compound is represented by Chemical Formula 1: [Chemical Formula 1] Wherein, in Chemical Formula 1, ^X1 and ^X2 are each independently an oxygen atom or a sulfur atom, ^R1 and ^R2 are each independently a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group, and ^L1 is a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C1 to C20 oxyalkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, or a combination thereof, and the second polymerizable compound is represented by Chemical Formula 2: [Chemical Formula 2] Wherein, in Chemical Formula 2, ^X3 and ^X4 are each independently an oxygen atom or a sulfur atom, ^R3 is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group, ^L2 is a single bond or a substituted or unsubstituted C1 to C20 alkylene group, L ³ is a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C1 to C20 oxyalkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, or a combination thereof, and n is an integer from 1 to 4, wherein the curable composition is a solvent-free curable composition or a solvent-curable composition, wherein, based on the total amount of the solvent-free curable composition, the solvent-free curable composition comprises: 5 wt % to 60 wt % of the surface-modified quantum dots; and 40 wt % to 95 wt % of the polymerizable compound; or, based on the total amount of the solvent-based curable composition, the solvent-based curable composition comprises: 1 wt % to 40 wt % of the surface-modified quantum dots; 1 wt % to 20 wt % of the polymerizable compound; and 40 wt % to 80 wt % of the solvent. The curable composition of claim 1, wherein the first polymerizable compound has a refractive index greater than or equal to 1.56. The curable composition of claim 1, wherein Chemical Formula 1 is represented by Chemical Formula 1-1: [Chemical Formula 1-1] In Formula 1-1, ^X1 and ^X2 are each independently an oxygen atom or a sulfur atom, ^R1 and ^R2 are each independently a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group, and ^L1 is a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C1 to C20 oxyalkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, or a combination thereof. The curable composition of claim 1, wherein the first polymerizable compound is represented by Chemical Formula 1-1-1 or Chemical Formula 1-1-2: [Chemical Formula 1-1-1] [Chemical formula 1-1-2] . The curable composition of claim 1, wherein Chemical Formula 2 is represented by Chemical Formula 2-1: [Chemical Formula 2-1] In Formula 2-1, ^X3 and ^X4 are each independently an oxygen atom or a sulfur atom, ^R3 is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group, ^L2 is a single bond or a substituted or unsubstituted C1 to C20 alkylene group, and ^L3 is a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C1 to C20 oxyalkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, or a combination thereof. The curable composition of claim 1, wherein the second polymerizable compound comprises at least one selected from Chemical Formula 2-1-1 to Chemical Formula 2-1-3: [Chemical Formula 2-1-1] [Chemical formula 2-1-2] [Chemical formula 2-1-3] . The curable composition of claim 1, wherein the second polymerizable compound has a refractive index greater than or equal to 1.5 and a viscosity less than 10 centipoise. The curable composition of claim 1, wherein the first polymerizable compound and the second polymerizable compound are contained in a weight ratio of 5:5 to 1:9. The curable composition of claim 1, wherein the curable composition further comprises a polymerization initiator, a photodiffuser, a polymerization inhibitor, or a combination thereof. The curable composition of claim 9, wherein the light diffuser comprises barium sulfate, calcium carbonate, titanium dioxide, zirconium oxide, or a combination thereof. The curable composition of claim 1, wherein the surface-modified quantum dots comprise a cadmium-free luminescent material. A curable composition as described in claim 11, wherein the surface-modified quantum dots have an InP/ZnS core/shell structure or an InP/ZnSe/ZnS core/first shell/second shell structure. The curable composition of claim 1, wherein the surface-modified quantum dots comprise a core comprising silver (Ag), indium (In), gallium (Ga), and sulfur (S) and a shell comprising at least two or more selected from the group consisting of Ag, Ga, Zn, and S. A cured layer is made using the curable composition as described in any one of claims 1 to 13. A display device comprises the cured layer as claimed in claim 14.