KR20200115143A - Quantum dot dispersion and composition for forming coating layer including quantum dot dispersion - Google Patents

Abstract

An object of the present invention is to provide a quantum dot dispersion capable of suppressing an increase in the half width of a peak at a desired wavelength of a fluorescence spectrum and improving light emission intensity (i.e., fluorescence intensity) than before, and a coating layer-forming composition thereof. The object is achieved by the quantum dot dispersion containing a quantum dot, a light scattering agent, a fluorescent dye, and a solvent, wherein the quantum dot has an absorption spectrum in which a bottom exists in a region with a wavelength of 480 nm or less and a peak exists in a region with a wavelength greater than 480 nm, and a fluorescence spectrum in which a peak exists in a region with a wavelength of 495 to 570 nm; and the fluorescent dye has a fluorescence spectrum in which a peak of fluorescence emission exists between a wavelength A1 of the bottom of the quantum dot and a wavelength A2 of the peak of the absorption spectrum, and a half width of the peak of the fluorescence emission is less than twice the half width of the peak of the fluorescence spectrum of the quantum dot.

Description

TECHNICAL FIELD The composition for forming a coating film including a quantum dot dispersion and a quantum dot dispersion TECHNICAL FIELD OF THE INVENTION

The present invention relates to a composition for forming a coating film comprising a quantum dot dispersion and a quantum dot dispersion.

Since quantum dots are nanometer-sized semiconductor crystals, band gaps are created between electron energy levels due to quantum blockade. The size of this bandgap can be controlled by, for example, the size of the quantum dots. Therefore, by controlling the size of the quantum dots, it is possible to highly control the optical properties. For example, by controlling the size of the quantum dot, it is possible to control the fluorescence wavelength to emit light. In addition, quantum dots are characterized by emitting fluorescence with a narrow spectrum width. Quantum dots having such characteristics have been studied to be used as constituent materials, such as a light emitting layer of a light emitting display element of an image display device and a wavelength conversion layer of a light wavelength conversion sheet of a backlight device (Patent Documents 1 and 2). Further, in order to improve the light efficiency and light emission intensity of such a light emitting layer or a wavelength conversion layer, it has been proposed to use a combination of quantum dots and a light scattering agent (Patent Document 3).

In addition, in Patent Document 4, in order to improve the color gamut of a liquid crystal display device, it is described that a quantum dot is used as a substitute for a conventional phosphor material, and as an example, a combination of a quantum dot and a fluorescent dye, which is a conventional phosphor material, is described. It is described.

Patent Document 1: Japanese Patent Laid-Open No. 2017-25165 Patent Document 2: International Publication No. 2017/086362 Patent Document 3: Japanese Patent Laid-Open No. 2016-98375 Patent Document 4: Japanese Patent Laid-Open No. 2017-532599

According to the review of the present inventors, it is possible to improve light emission intensity and the like by using a combination of quantum dots and light scattering agents, as in the prior art described above, but there is still room for improvement to further improve the image quality of the image display device. It turned out to be. In addition, even if a quantum dot and a fluorescent dye material such as a fluorescent dye other than that are used in combination, the effect of improving the light emission intensity cannot be said to be sufficient, and it has been found that the half width of the peak at a desired wavelength of the fluorescent spectrum increases. The increase in half-width in this way means that the characteristic of the quantum dot that emits fluorescence with a narrow spectrum width is impaired.

Accordingly, it is an object of the present invention to provide a quantum dot dispersion and coating film-forming composition capable of suppressing an increase in the half-width of the peak at a desired wavelength of the fluorescence spectrum and improving the luminous intensity (i.e., fluorescence intensity) than before. It is in offering.

The inventor of the present invention has conducted intensive examinations in order to solve the above-described problems. As a result, it was found that the above-described problem was solved by using a quantum dot and a light scattering agent in combination, and by using a fluorescent dye having a specific fluorescence spectrum in relation to the absorption and fluorescence spectrum of the quantum dot.

The first of the present invention is a quantum dot dispersion comprising a quantum dot, a light scattering agent, a fluorescent dye, and a solvent, wherein the quantum dot has a bottom in a region having a wavelength of 480 nm or less and a region having a wavelength of greater than 480 nm Has an absorption spectrum in which a peak is present in, and has a fluorescence spectrum in which a peak is present in a region with a wavelength of 495 to 570 nm, and the fluorescent dye has a wavelength A1 of the bottom of the quantum dot and the peak of the absorption spectrum It relates to a quantum dot dispersion having a fluorescence spectrum in which a peak of fluorescence emission exists between the wavelength A2 of and the half width of the peak of fluorescence emission is less than twice the half width of the peak of the fluorescence spectrum of the quantum dot. .

In the embodiment of the present invention, the fluorescent dye absorbs the excitation light of the wavelength A3 on the lower wavelength side than the wavelength A1, and in the fluorescence spectrum, the following formula ( At wavelengths between wavelengths A4 satisfying the relational expression of 1), fluorescence having a peak at wavelength A5 satisfying the relational expression of the following expression (2) may be emitted.

A4=A1+(A1-A3)<A2 (One)

A4≤A5≤A2 (2)

In the embodiment of the present invention, the light scattering agent may be at least one selected from metal compounds.

In the embodiment of the present invention, the fluorescent dye may be at least one selected from coumarin-based dyes.

The second of the present invention relates to a composition for forming a coating film comprising the quantum dot dispersion and a coating film forming component described above.

According to the present invention, it is possible to suppress an increase in the half-width of the peak at a desired wavelength of the fluorescence spectrum, and to provide a quantum dot dispersion and coating film forming composition capable of improving light emission intensity (i.e., fluorescence intensity) than before. It is possible.

1 is an explanatory diagram schematically showing absorption and fluorescence spectra of quantum dots and fluorescent dyes usable in an embodiment of the present invention.
2A is a diagram showing a part of the normalized absorption spectrum of the quantum dot and the fluorescent dye used in Example 1. FIG. 2B is a diagram showing a part of the standardized fluorescence spectrum of the quantum dot and the fluorescent dye used in Example 1. FIG.
3 is a diagram showing a part of fluorescence spectra of Examples 1 and 2, Comparative Examples 1 to 4, and blanks.

Hereinafter, a quantum dot dispersion according to an embodiment of the present invention will be described.

(Quantum dot dispersion)

The quantum dot dispersion according to the embodiment of the present invention contains a quantum dot, a light scattering agent, a fluorescent dye, and a solvent. In addition, quantum dots have an absorption spectrum of light in which a bottom exists in a region with a wavelength of 480 nm or less and a peak exists in a region with a wavelength greater than 480 nm, and a peak exists in a region with a wavelength of 495 to 570 nm. It has a fluorescence spectrum. Further, in the fluorescent dye, a peak of fluorescence emission exists between the wavelength A1 of the bottom of the quantum dot and the wavelength A2 of the peak of the absorption spectrum, and the half width of the peak of the fluorescence emission is the fluorescence spectrum of the quantum dot It has a fluorescence spectrum that is less than twice the half width of the peak of. Here, in the absorption spectrum of light, the bottom is a portion that changes from a decrease to an increase in the case where the absorbance continuously decreases and then increases as the wavelength increases, and the peak is a part in which the absorbance continuously increases as the wavelength increases. It is a part that changes from increase to decrease in case of successive decrease after. That is, even if a plurality of peaks overlap, for example, the bottom and peak are not formed unless an increase or decrease in absorbance is accompanied by an increase in wavelength. In addition, as for the absorbance of the bottom and the peak at that time, it is assumed that the average value of each bottom and each peak is adopted. In addition, the wavelength at both ends is included between the wavelength and the wavelength. For example, between the wavelength A1 and the wavelength A2, the wavelength A1 and the wavelength A2 are included.

In this way, when a quantum dot has a specific absorption and fluorescence spectrum, corresponding to the absorption and fluorescence spectrum, a fluorescent dye having a specific fluorescence spectrum is used. Thereby, the following actions can be exhibited. A fluorescent dye absorbs light in a wavelength region not used by a quantum dot (a region near the wavelength A1), and a wavelength region of light absorbed by the quantum dot (a region near the wavelength A2). Fluorescence can be emitted by a fluorescent dye in a wavelength region (between wavelength A1 and wavelength A2) close to a wavelength region for emitting fluorescence. For this reason, fluorescence intensity can be improved by the sum of fluorescence emission by the quantum dot and fluorescence emission by a fluorescent dye. In addition, the sum of the fluorescence emission of the quantum dot and the fluorescent dye by the half width of the peak of the fluorescence emission by the fluorescent dye is less than twice the half width of the peak of the fluorescence spectrum of the quantum dot, preferably 1.6 times or less. It is possible to suppress the expansion of the half-width of the peak of fluorescence emission of the coating film (cured film) formed by this. Further, since the fluorescence emission of the fluorescent dye on the longer wavelength side than the fluorescence emission peak of the quantum dot can be suppressed, the expansion of the half width of the fluorescence emission peak of the coating film (cured film) can be suppressed. And, by the presence of the light scattering agent, the effect of improving the fluorescence intensity and the effect of suppressing the expansion of the half value width are further improved. In addition, it is known that the fluorescence emission peak of the quantum dot appears at a wavelength greater than the absorption wavelength.

The relationship between the absorption of the quantum dot and the fluorescent dye and the fluorescence spectrum may be as described above, but from the viewpoint of further improving the effect of improving the fluorescence intensity and the suppressing effect of the expansion of the half value width, the fluorescent dye has a lower wavelength than the wavelength A1. Absorbs the excitation light of wavelength A3 on the side, and in its fluorescence spectrum, the following equation (2) at a wavelength between the wavelength A2 and a wavelength A4 that satisfies the equation (1) below on the longer wavelength side than the wavelength A1 It is preferable to emit fluorescence in which a peak exists at wavelength A5 that satisfies the relation of ).

A4=A1+(A1-A3)<A2 (One)

A4≤A5≤A2 (2)

The wavelengths A1 to 5 will be described in detail with reference to FIG. 1 as follows. 1 is an explanatory diagram schematically showing a part of a fluorescence spectrum and absorption of a quantum dot and a fluorescent dye usable in an embodiment of the present invention. Incidentally, the absorbance (normalized value) on the left vertical axis in Fig. 1 and the fluorescence intensity (normalized value) on the right vertical axis are normalized values calculated by dividing by each measured value at the wavelength of each peak in Fig. 1. In addition, the absorption spectrum (ii) of the fluorescent dye was normalized based on the value of the peak near the wavelength of 440 nm.

In the example shown in Fig. 1, the absorption spectrum of the quantum dot (symbol i in Fig. 1) has a single bottom at the position of the wavelength (absorption wavelength) monotonically decreasing from 430 nm, and from 460 nm to 495 nm. The bottom and the peak are continuous with one peak at the position where the wavelength (absorption wavelength) is 495 nm and decreases monotonically from 495 nm to 600 nm. That is, in the absorption spectrum (i) of the quantum dot, the wavelength A1 of the bottom is 460 nm, and the wavelength A2 of the peak is 495 nm.

Fluorescence spectrum of quantum dots (sign iii in Fig. 1) has one peak at the position of wavelength (fluorescence wavelength) 530 nm, the fluorescence intensity from the wavelength 450 nm to the peak increases monotonically, and from the peak to 600 nm monotonic Decreases to

In the absorption spectrum of the fluorescent dye (reference numeral ii in Fig. 1), two peaks exist between a wavelength of 440 to 460 nm. That is, the excitation light efficiently absorbs the excitation light by making it the excitation light on the wavelength side lower than the wavelength of 460 nm (A1), and more preferably the light having a wavelength (A3) between 440 and 460 nm. Can emit light. In addition, in the example shown in FIG. 1, the absorption spectrum (ii) of the fluorescent dye has two peaks between 440 and 460 nm. Here, a wavelength of 450 nm at a position in the middle of the two peaks is the wavelength A3 of the excitation light. In addition, in the fluorescence spectrum of the fluorescent dye (symbol iv in Fig. 1), a peak of fluorescence emission exists at a wavelength of 495 nm between the wavelength A1 and the wavelength A2. In the fluorescence spectrum iv of the fluorescent dye shown in FIG. 1, a peak of fluorescence emission exists at a wavelength of 495 nm equal to the wavelength A2, but a peak of fluorescence emission in a region of a wavelength A5 that satisfies Equations (1) and (2) above. You just need it. That is, the peak wavelength A5 of fluorescence emission is the difference between the wavelength A3 of the excitation light and the wavelength A1 of the bottom, which is ``A1-A3 (=460 nm-450 nm=10 nm)'', and the wavelength A4 (470) on the longer wavelength side than the bottom wavelength A1. nm) and the peak wavelength A2 (reference numeral L2 in FIG. 1). However, in the example shown in FIG. 1, the fluorescence emission peak at the wavelength A2 closest to the peak of the fluorescence emission of the quantum dot (wavelength 530 nm) and the same as the peak of the absorption spectrum, which is the wavelength absorbed by the quantum dot. Since it is desirable, it is appropriate that the wavelength A5 coincides with A2.

The quantum dot should just have the absorption spectrum mentioned above, and it is preferable as long as it has the fluorescence spectrum mentioned above. Known quantum dots can be used depending on the application or the like. For example, those described in Patent Documents 1 to 3 can be used. Specifically, for example, a semiconductor material containing a group 2 element, a group 11 to 16 element, and combinations thereof can be mentioned. Further, in the case of a light emitting display device use, it is preferable to include a compound having a fluorescent emission peak in a green wavelength region of 500 to 600 nm. This is because in a light emitting display element, blue light emitted from a blue LED is often used as excitation light. In addition, in the case of correcting blue light by, for example, quantum dots, it is preferable to include, in addition to green, a compound having a fluorescence emission peak in a blue wavelength region of 400 to 500 nm.

The structure of the quantum dot is not particularly limited, and examples thereof include a homogeneous single-phase structure, a core-shell structure, and the like. Further, at least a part of the surface of a semiconductor material having a single-phase structure or a core-shell structure may be coated with an organic ligand.

The particle diameter of the quantum dot is preferably 4.0 to 5.0 nm in the case of emitting green fluorescence.

One type of quantum dot may be included, but two or more types may be included.

The content of the quantum dots in the quantum dot dispersion can be appropriately determined depending on the application and the like, and for example, in the case of a display device use, it can be set to 0.5 to 5% by weight.

The fluorescent dye may have a predetermined spectrum in relation to the above-described spectrum of the quantum dot. Examples of such fluorescent dyes include fluorescent dyes such as coumarin-based and perylene, and fluorescent pigments. When exemplified by a color index (C.I.) number, Disperse Yellow 82 and 184, and Solvent Yellow 159 may be mentioned.

Examples of the light scattering agent include known particles such as particles of metal compounds and resin particles described in Patent Document 3 and the like. As a metal compound, for example, antimony-doped tin oxide (ATO), indium tin oxide (ITO), In-Zn-O (IZO), MgO, Al ₂ O ₃ , TiO ₂ , BaTiO ₃ , Sb ₂ O ₅ , SiO ₂ , ZrO ₂ , ZnO, ZnO-Al, Ta ₂ O ₅ , Ti ₃ O ₅ , Metal oxides such as Nb ₂ O ₃ , MgF ₂ , and the like. As resin, acrylic resin, styrene resin, melamine resin, urethane resin, etc. are mentioned. The particles of a metal compound or resin may have their surfaces treated as necessary.

The average particle diameter of the various particles constituting the light scattering agent is preferably 20 to 2000 times the average particle diameter of the quantum dots from the viewpoint of imparting a good scattering effect. Therefore, when a quantum dot emits green fluorescence, 0.08 µm to 10 µm is preferable, 0.1 µm to 5 µm is more preferable, and 0.1 to 1 µm is still more preferable.

The shape of the various particles constituting the light scattering agent is not particularly limited, and examples thereof include a spherical shape such as a spherical shape, a substantially spherical shape, and an elliptical spherical shape; Polyhedral type; A rod shape such as a cylinder shape and a prism shape; Flat plate type; Scale type; Indefinite shape, etc. are mentioned. In addition, the particle diameter of the various particles constituting the light scattering agent can be set to a value of a spherical shape having the same volume when the shape is not spherical.

The content of the light scattering agent is preferably 3 to 15% by weight in the quantum dot dispersion.

The solvent should just be one capable of dispersing quantum dots, and can be appropriately selected depending on the application. For example, ketone-based organic solvents, ester-based organic solvents, ether-based organic solvents, alcohol-based organic solvents, amide-based polar organic solvents, sulfinyl group (-SO-) or sulfonyl group (-S(=O) ₂ -) And a sulfur-containing polar organic solvent. The solvent may be only one type or a combination of two or more. Hereinafter, in the case of using a quantum dot dispersion as a constituent material of a light emitting layer or a wavelength conversion layer, a use for manufacturing by photolithography (hereinafter referred to as ``photolithography use'') and a use for manufacturing by an inkjet method (hereinafter And "inkjet use"), respectively.

As a ketone-based organic solvent, for photolithography use, for example, 3,5,5-trimethyl-2-cyclohexen-1-one (isophorone), 3,3,5-trimethylcyclohexanone, 2-hep Tanone, 4-heptanone, diisobutyl ketone, methyl isobutyl ketone, cyclohexanone, methyl ethyl ketone, etc. are mentioned.

Moreover, as an inkjet application, acetone etc. are mentioned, for example.

As the ester organic solvent, for photolithography use, for example, methyl lactate, ethyl 3-ethoxypropionate, ethyl lactate, n-propylacetate, triacetin, n-amyl acetate, isoamyl acetate, isobutyl acetate, Cyclohexanol acetate, propylene glycol monomethyl ether propionate, 1,3-butylene glycol diacetate, propylene glycol diacetate, dibasic acid ester, ethyl acetate, n-butyl acetate, propyl acetate, γ-butyrolactone, 3-Methoxy-3-methylbutyl acetate, 3-methoxybutyl acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, dipropylene glycol Methyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate (PMA), and the like.

In addition, for inkjet applications, for example, methyl acetate, methyl propionate, ethyl propionate, δ-valerolactone, ε-caprolactone, α-ethyllactone, α-acetolactone, β-propiolactone, ζ-enantiolac Tone, η-caprylolactone, γ-valerolactone, γ-heptalactone, γ-nonalactone, β-methyl-δ-valerolactone, 2-butyl-2-ethylpropiolactone, α,α -Diethylpropiolactone, β-butyrolactone, ethylene glycol monopropyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, dimethylene glycol monomethyl ether acetate, dimethylene glycol monoethyl ether acetate, Dimethylene glycol monopropyl ether acetate, Diethylene glycol monobutyl ether acetate, Diethylene glycol monomethyl ether acetate, Diethylene glycol monopropyl ether acetate, Diethylene glycol monobutyl ether acetate (butyl diglycol acetate, BDGAC), Dipropylene Glycol monomethyl ether acetate (DPMA), dipropylene glycol monoethyl ether acetate, dipropylene glycol monopropyl ether acetate, dipropylene glycol monobutyl ether acetate, trimethylene glycol monomethyl ether acetate, trimethylene glycol monoethyl ether acetate, tri Methylene glycol monopropyl ether acetate, trimethylene glycol monobutyl ether acetate, triethylene glycol monomethyl ether acetate, triethylene glycol monoethyl ether acetate, triethylene glycol monopropyl ether acetate, triethylene glycol monobutyl ether acetate, tripropylene glycol Monomethyl ether acetate, tripropylene glycol monoethyl ether acetate, tripropylene glycol monopropyl ether acetate, tripropylene glycol monobutyl ether acetate, 3-methoxybutyl acetate, 3-methoxy-3-methyl-1-butyl acetate, etc. Can be mentioned.

As an ether organic solvent, for photolithography use, for example, ethylene glycol monobutyl ether, diethylene glycol monoisopropyl ether, 1,4-dioxane, ethylene glycol monoisopropyl ether, ethylene glycol monoethyl ether , Ethylene glycol monobutyl ether, ethylene glycol monopropyl ether, ethylene glycol monohexyl ether, ethylene glycol monomethyl ether, diethylene glycol monobutyl ether, diethylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono Butyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, propylene glycol phenyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, propylene glycol Monopropyl ether, propylene glycol monomethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, ethylene glycol dimethyl ether, propylene glycol dimethyl ether And the like.

In addition, for inkjet applications, for example, diethyl ether, dipropyl ether, tetrahydrofuran, ethylene glycol monophenyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, tetraethylene Glycol monomethyl ether, tetraethylene glycol monoethyl ether, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol dibutyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl Ether, tetraethylene glycol dibutyl ether, propylene glycol diethyl ether, dipropylene glycol diethyl ether, tetraethylene glycol monobutyl ether, diethylene glycol methyl ethyl ether, ethylene glycol monopentyl ether, ethylene glycol mono-2-ethylhexyl Ether, propylene glycol monopentyl ether, propylene glycol monohexyl ether, propylene glycol mono-2-ethylhexyl ether, dimethylene glycol monomethyl ether, dimethylene glycol monoethyl ether, dimethylene glycol monopropyl ether, dimethylene glycol monobutyl Ether, dimethylene glycol monopentyl ether, dimethylene glycol monohexyl ether, dimethylene glycol mono-2-ethylhexyl ether, diethylene glycol monopropyl ether, diethylene glycol monopentyl ether, diethylene glycol monohexyl ether, diethylene Glycol mono-2-ethylhexyl ether, dipropylene glycol monopentyl ether, dipropylene glycol monohexyl ether, dipropylene glycol mono-2-ethylhexyl ether, trimethylene glycol monomethyl ether, trimethylene glycol monoethyl ether, trimethylene Glycol monopropyl ether, trimethylene glycol monobutyl ether, trimethylene glycol monopentyl ether, trimethylene glycol monohexyl ether, trimethylene glycol mono-2-ethylhexyl ether, triethylene glycol monopropyl ether, triethylene glycol monopentyl ether , Triethylene glycol monohexyl ether, triethylene glycol mono-2-ethylhexyl ether, tripropylene glycol monoethyl ether, tripropylene glycol monopropyl ether, tripropylene glycol monopentyl ether, tripropylene glycol monohexyl ether, tripropylene glycol Mono-2-ethylhexyl ether, triethylene glycol butyl methyl ether, dimethylene glycol monophenyl ether, dimethylene glycol monobenzyl ether Le, dimethylene glycol monotolyl ether, trimethylene glycol monophenyl ether, trimethylene glycol monobenzyl ether, trimethylene glycol monotolyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, ethylene glycol monotolyl ether, diethylene Glycol monophenyl ether, diethylene glycol monobenzyl ether, diethylene glycol monotolyl ether, triethylene glycol monophenyl ether, triethylene glycol monobenzyl ether, triethylene glycol monotolyl ether, propylene glycol monobenzyl ether, propylene glycol monotolyl Ether, dipropylene glycol monophenyl ether, dipropylene glycol monobenzyl ether, dipropylene glycol monotolyl ether, tripropylene glycol monophenyl ether, tripropylene glycol monobenzyl ether, tripropylene glycol monotolyl ether, and the like.

As the alcohol-based organic solvent, for photolithography use, for example, benzyl alcohol, 1,3-butanediol, 2-methyl-1,3-propanediol, 3-methyl-1,3-butanediol, methylcyclohexanol, Diacetone alcohol (diacetone alcohol), cyclohexanol, 3-methoxy-3-methyl-1-butanol, 3-methoxybutanol, n-butyl alcohol, isobutyl alcohol, methanol, ethanol, isopropyl alcohol, etc. Can be lifted.

In addition, for inkjet applications, for example, fluorinated alcohol, glycerin, 1,2,6-hexanetriol, trimethylolpropane, pentamethylene glycol, trimethylene glycol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene Glycol, pentaethylene glycol, polyethylene glycol with a number average molecular weight of 2000 or less, propylene glycol, dipropylene glycol, tripropylene glycol, isobutylene glycol, 2-butene-1,4-diol, 2-ethyl-1,3-hexane Diol, 2-methyl-2,4-pentanediol, mesoerythritol, pentaerythritol, 1,2-pentanediol, 1,2-hexanediol, 1,3-propanediol, 1,4-butanediol, 1, 5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, etc. are mentioned.

Examples of the amide polar organic solvent include N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, and the like for photolithography applications.

In addition, for inkjet use, for example, 2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-butyl-2-pyrrolidone, 5-methyl-2 -Pyrrolidone, etc. are mentioned.

Examples of the sulfur-containing polar organic solvent having a sulfinyl group (-SO-) or a sulfonyl group (-S(=O) ₂ -) include dimethyl sulfoxide, dimethyl sulfone, sulfolane, etc. have.

From the viewpoint of obtaining better dispersibility and half width of the quantum dots, the solvent is preferably 10 to 1000 g/L-water solubility in water at 25°C. Examples of such a solvent include ester solvents such as PMA, DPMA, and BDGAC.

The content of the solvent is preferably 75 to 90% by weight in the quantum dot dispersion from the viewpoint of dispersion stability.

The quantum dot dispersion may contain other components in addition to the above components. Examples of such components include a dispersant, a dispersion resin, an adhesive imparting agent, and an antioxidant.

As the dispersant, a known dispersant can be used, but from the viewpoint of suppressing agglomeration of quantum dots or other particles optionally added in the quantum dot dispersion, reducing the quantum yield and expanding the half width of the resulting quantum dot dispersion, phosphoric acid Ester dispersants are preferred.

Phosphoric acid ester dispersants are, for example, X _a P(=O)(OH) _3-a (wherein X is an organic group having affinity for a solvent, and when a is 2 or 3, it may be the same or different. Good. A is an integer of 1-3. What contains a phosphoric acid ester etc. represented by) as an active ingredient is mentioned. As X in the formula, a polyoxyalkylene alkyl ester group etc. are mentioned, for example. In addition, a commercially available phosphate ester dispersant can be used. For example, Japan's Lubrizol Co., Ltd.manufacture: Solplus D520, D540, Solspurs 26000, 36000, 41000, Big Chemie Japan Co., Ltd.manufacture: DISPERBYK (registered trademark)-102, 110, 111, 118, BYK W972, Kusumoto Hwasung Co., Ltd. manufacture: HIPLAAD151, 153, 154, AQ-330, Daiichi Kogyo Co., Ltd. manufacture: Flysurf AL, A212C, A215C, BASF Japan Co., Ltd. manufacture: Efka 5220, etc. are mentioned.

The acid value of the phosphate ester dispersant is preferably 110 to 250 mgKOH/g, more preferably 150 to 250 mgKOH/g, and more preferably 200 to 250 mgKOH/g from the viewpoint of suppressing the decrease in the properties of quantum dots. More preferable. The amine value is preferably 30 mgKOH/g or less, and more preferably 0 mgKOH/g. The acid value (acid value in terms of solid content) can be obtained, for example, by a method conforming to DIN EN ISO 2114, and the amine number (amine value in terms of solid content) can be obtained by, for example, a method conforming to DIN 16945. .

The content of the dispersant is preferably 70 to 200% by weight based on 100% by weight of quantum dots from the viewpoint of dispersion stability.

The dispersion resin can be contained as needed from the viewpoint of improving the dispersion stability of particles in the quantum dot dispersion and in the composition for forming a coating film. In particular, in the composition for forming a coating film, it is suitable to use when the coating-film forming component contains a photopolymerizable component. As such a dispersion resin, an alkali-soluble resin mentioned later is mentioned.

It is preferable that content of a dispersion resin is 5 to 25 weight% of quantum dots from a viewpoint of dispersion stability and film-forming property.

The quantum dot dispersion can be obtained by mixing the above-described various components and dispersing them uniformly. In addition, the method of mixing various components is not particularly limited, and all components may be mixed at once, or a dispersion of quantum dots and a dispersion of a light scattering agent may be prepared beforehand and then mixed. Further, a dispersant to be added as necessary may be added when preparing a dispersion of a quantum dot or a dispersion of a light scattering agent.

(Composition for coating film formation)

The composition for forming a coating film according to an embodiment of the present invention contains the above-described quantum dot dispersion and a component for forming a coating film. In addition, when the quantum dot dispersion is used as a raw material, such as a light emitting layer of a light emitting display element, if necessary, an alkali-soluble resin, a dispersant (except for the aforementioned phosphate ester dispersant), a dispersion aid, and a pigment. , Dyes, and other known components can be contained in a predetermined amount.

The coating film forming component is not particularly limited as long as it is a component capable of forming a coating film, and may be a polymerizable component, may be a polymer, or a mixture thereof. As the polymerizable component, since it is easy to perform patterning by development (negative development), a photopolymerizable component is preferable. In addition, as the polymer, for example, thermoplastic urethane resin, (meth)acrylic resin, polyamide resin, polyimide resin, styrene maleic acid resin, polyester resin, epoxy resin, silicone resin, cardo resin, etc. Can be lifted. The molecular weight of the polymer can be appropriately determined. Further, when a polymerizable component and a polymer are used in combination, the crosslinking property is improved and the strength of the coating film tends to be improved. In addition, there is a tendency that, for example, an epoxy resin or the like is included to improve the luminous properties.

The photopolymerizable component that can be used includes a photopolymerizable compound and a photopolymerization initiator. Such photopolymerizable compounds and photopolymerization initiators can be used, for example, those described in Japanese Patent Laid-Open No. 2009-179789. In detail, such a photopolymerizable compound is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and is selected from compounds having at least one, preferably two or more terminal ethylenically unsaturated bonds. These groups of compounds are widely known in the art, and they can be used without particular limitation in the present invention. The photopolymerizable compound has, for example, a chemical form such as a monomer, a prepolymer, that is, a dimer, a trimer and an oligomer, or a mixture thereof and a copolymer thereof.

Examples of the monomer and its copolymer include unsaturated carboxylic acids (e.g., acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters and amides thereof, and preferred Preferably, esters of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound, and amides of an unsaturated carboxylic acid and an aliphatic polyhydric amine compound are used. In addition, an unsaturated carboxylic acid ester having a nucleophilic substituent such as a hydroxyl group, an amino group, or a mercapto group, or an addition reaction product of an amide and a monofunctional or polyfunctional isocyanate or epoxy, and a monofunctional or polyfunctional carboxyl Dehydration and condensation reaction products with acids are also suitably used. In addition, addition reaction products of unsaturated carboxylic acid esters or amides having an electrophilic substituent such as an isocyanate group or an epoxy group with monofunctional or polyfunctional alcohols, amines, and thiols, and leavingable substituents such as halogen groups and tosyloxy groups Substitution reaction products of unsaturated carboxylic acid esters or amides with monofunctional or polyfunctional alcohols, amines, and thiols are also suitable. Further, as another example, instead of the unsaturated carboxylic acid, a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether, or the like may be used.

In addition, specific examples of these are roughly the same as those described in Japanese Patent Laid-Open No. 2009-179789, but as a specific example of the monomer of an aliphatic polyhydric alcohol compound and an ester of an unsaturated carboxylic acid, ethylene glycol diacrylic as an acrylic acid ester Rate, triethylene glycol diacrylate, 1,3-butanediol diacrylate, tetramethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane tri( Acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate, 1,4-cyclohexanediol diacrylate, tetraethylene glycol diacrylate, pentaerythritol diacrylate, pentaerythritol tri Acrylate, pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol hexaacrylate, dipentaerythritol pentaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol Hexaacrylate, tri(acryloyloxyethyl) isocyanurate, polyester acrylate oligomer, isocyanuric acid EO-modified triacrylate, and the like.

Regarding these addition polymerizable compounds, the details of the structure, whether it is used alone or in combination, and the usage method such as the amount of addition can be arbitrarily set according to the performance design of the final coating film-forming composition.

For example, it is selected from the following viewpoints. In terms of sensitivity, a structure having a high content of unsaturated groups per molecule is preferable, and in most cases, two or more functions are preferable. In addition, in order to increase the strength of the coating film, it is preferable to have three or more functions, and by using a combination of a different number of functions and a different polymerizable group (e.g., acrylic acid ester, methacrylic acid ester, styrene compound, vinyl ether compound) Also, a method of controlling both sensitivity and intensity is effective.

In addition, for compatibility and dispersibility with other components in the composition for coating film formation (e.g., binder polymer such as alkali-soluble resin, photopolymerization initiator, colorant (quantum dot, pigment, etc.)), the selection and use of the addition polymerization compound is important. It is a factor, and compatibility may be improved, for example, by use of a low-purity compound or a combination of two or more.

In addition, a specific structure may be selected for the purpose of improving adhesion to a substrate or the like. The photopolymerizable compound is contained in an amount of preferably 5 to 70% by weight, more preferably 10 to 60% by weight, based on the nonvolatile component in the composition for forming a coating film. In addition, these may be used alone or in combination of two or more. In addition, the use of the photopolymerizable compound can be arbitrarily selected from the viewpoint of the size, resolution, cloudiness, refractive index change, and surface adhesion of the polymerization inhibition to oxygen.

As the photopolymerization initiator, those described in Japanese Patent Laid-Open No. 2009-179789 can be used.

For example, acetophenone, ketal, benzophenone, benzoin, benzoyl, xanthone, active halogen compounds (triazine, oxadiazole, coumarin), acridine, biimidazole, oxime ester, etc. to be.

Specific examples of these are benzophenone-based photopolymerization initiators, for example, benzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, 4 And 4'-dichlorobenzophenone.

The content of the photoinitiator in the coating film-forming composition is preferably 0.1 to 10.0 mass%, and more preferably 0.5 to 5.0 mass% with respect to the total solid content of the coating film-forming composition. When the content of the photopolymerization initiator is within this range, the polymerization reaction proceeds favorably and a film having good strength can be formed.

When a photopolymerizable component is included as a coating film forming component, an alkali-soluble resin may be contained. When the alkali-soluble resin is contained, for example, in a photolithography process, when the composition for forming a coating film is applied to pattern formation, pattern formation can be further improved.

As such an alkali-soluble resin, those described in Japanese Patent Laid-Open No. 2009-179789 can be used. Briefly, the alkali-soluble resin is, for example, a linear organic polymer, a group that promotes alkali solubility of at least one in a molecule (preferably, a molecule having an acrylic copolymer or a styrene copolymer as a main chain) (e.g. , A carboxyl group, a phosphoric acid group, a sulfonic acid group, etc.). Among them, more preferably, it is soluble in an organic solvent and can be developed with a weak alkaline aqueous solution.

As suitable examples of the alkali-soluble resin, in particular, a copolymer of (meth)acrylic acid and another monomer copolymerizable therewith may be mentioned. Here, (meth)acrylic acid is a generic term combining acrylic acid and methacrylic acid, and in the same manner hereinafter, (meth)acrylate is a generic term for acrylate and methacrylate.

As another monomer copolymerizable with (meth)acrylic acid, an alkyl (meth)acrylate, an aryl (meth)acrylate, a vinyl compound, etc. are mentioned. Here, the hydrogen atom of the alkyl group and the aryl group may be substituted with a substituent.

Specific examples of the alkyl (meth) acrylate and aryl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (Meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, tolyl (meth)acrylate, naphthyl (Meth)acrylate, cyclohexyl (meth)acrylate, etc. are mentioned.

Examples of the vinyl compound include styrene, α-methylstyrene, vinyltoluene, glycidyl methacrylate, glycidyl acrylate, acrylonitrile, vinyl acetate, N-vinylpyrrolidone, tetrahydrofurfuryl methacrylate. Crylate, polystyrene macromonomer, polymethyl methacrylate macromonomer, CH ₂ =CR ⁵ R ⁶ , CH ₂ =C(R ⁵ )(COOR ⁷ ) (where R ⁵ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms And R ⁶ represents an aromatic hydrocarbon ring having 6 to 10 carbon atoms, and R ⁷ represents an alkyl group having 1 to 8 carbon atoms or an aralkyl group having 6 to 12 carbon atoms), percumylphenol ethylene oxide-modified acrylate, and the like. I can.

These other copolymerizable monomers may be used alone or in combination of two or more.

The weight average molecular weight of the alkali-soluble resin is preferably 5000 to 500,000 from the viewpoint of developability.

The alkali-soluble resin can be prepared from the above-described monomers or the like according to a method determined. Moreover, what is marketed can also be used. Specific examples of commercially available products are as follows, but are not limited thereto.

Showa Polymer Co., Ltd. manufacturing: lipoxy SPC-2000,

Manufactured by Mitsubishi Rayon Co., Ltd.: Diamondal NR series,

Diamond hamrock Co. Ltd., manufactured by: Photomer6173 (COOH-containing polyurethane acrylic oligomer),

Osaka Organic Chemical Industry Co., Ltd.manufacture: Viscoat R-264, KS resist 106, SOP-005,

Daicel Chemical Industries, Ltd.: Cyclomer P series, Fraxel CF 200 series,

Daicel Yushibi Co., Ltd.: Ebecryl 3800,

Nippon Shokubai Co., Ltd.: Aclique (registered trademark) RD-Y-503, RD-Y-702-A, etc.

The content of the alkali-soluble resin in the composition for forming a coating film is preferably 1 to 20% by weight, more preferably 2 to 15% by weight, and particularly preferably 3 to 12% by weight, based on the total solid content of the composition for forming a coating film. % By weight. When it is contained in a pigment dispersion as a dispersion resin, it is a total amount.

The composition for coating film formation can be obtained by mixing, stirring, and uniformly dispersing a quantum dot dispersion, a coating film-forming component, and an optional component used as necessary. For example, in the case of a composition for forming a coating film for photolithography, it can be obtained by mixing, stirring, and uniformly dispersing a quantum dot dispersion, a coating film forming component, an alkali-soluble resin, and an optional component used as necessary. In the case of a composition for forming an inkjet coating film, it can be obtained by using the same components as the composition for photolithography except for an alkali-soluble resin. In addition, coating film forming components, scattering particles, dispersants, dispersion aids, pigments, dyes and other known components can be appropriately determined according to each application for photolithography and inkjet.

Other optional components include, for example, a sensitizer (sensitizing dye), a chain transfer agent, a fluorine-based organic compound, a thermal polymerization initiator, a thermal polymerization component, a filler, an adhesion promoter, an antioxidant, an anti-aggregation agent, a surface modifier (leveling agent), etc. Additives are mentioned.

The composition for coating film formation can be suitably used for formation of coating films for various uses. Examples of the application of such a coating film include a color filter of a liquid crystal display device, a light emitting layer of a light emitting display element of a display device, a wavelength conversion layer, and the like. The coating film can be formed by applying a coating film-forming composition to the surface of a substrate and curing it under predetermined conditions. The coating film shall include a film before curing and a film after curing. In addition, the film after hardening is also called a cured film.

Example

Hereinafter, an embodiment according to the present invention will be described in more detail based on examples.

(Production Example 1) Preparation of dispersion of light scattering agent

As a light scattering agent, titanium dioxide (manufactured by Ishihara Industries, Typek (registered trademark) CR-60, 　 surface treatment completed, titanium dioxide content 95% by weight, average particle diameter 0.21 µm, rutile type) 70 parts by weight, dispersant (Lubrizol Corporation) Manufacture, Solspurs 36000. A polyphosphate polyester-based polymer dispersant with a main skeleton.) 3 parts by weight of propylene glycol monomethyl ether acetate (PMA) 27 parts by weight as a solvent were mixed, dispersed by a bead mill, and a dispersion of titanium dioxide ( A light scattering agent dispersion) was obtained.

(Production Example 2) Preparation of acrylic resin

70 parts by weight of propylene glycol monomethyl ether acetate was put in the reaction vessel, heated to 80° C. while nitrogen gas was injected into the container, and 12.3 parts by weight of benzyl methacrylate at the same temperature, 4.6 parts by weight of 2-hydroxyethyl methacrylate, 5.3 parts by weight of methacrylic acid, 7.4 parts by weight of percumylphenol ethylene oxide-modified acrylate ("Aronix M110" manufactured by Toa Synthesis Co., Ltd.) and 0.4 parts by weight of azobisisobutyronitrile were added dropwise over 2 hours to conduct a polymerization reaction. Did. After completion of the dropwise addition, after further reaction at 80°C for 3 hours, 0.2 parts by weight of azobisisobutyronitrile dissolved in 10 parts by weight of propylene glycol monomethyl ether acetate was added, and the reaction was continued at 80°C for 1 hour. A transparent resin solution was obtained. After cooling to room temperature, about 2 g of the transparent resin solution was sampled, heated and dried at 180° C. for 20 minutes to measure non-volatile content, and propylene glycol monomethyl ether acetate so that the non-volatile content was 20% by weight in the previously synthesized transparent resin solution. Was added to obtain an acrylic resin. The weight average molecular weight Mw of the obtained acrylic resin was 20000.

Components shown in Table 1 used in Examples 1 and 2 below and Comparative Examples 1 to 4 are as follows.

(1) quantum dot dispersion

InP/ZnS, which is a core-shell structure semiconductor quantum dot, was dispersed in PMA, and the concentration of the quantum dot was 10% by weight.

(2) fluorescent dye

Tokyo Chemical Industry Co., Ltd., 3-(2-benzothiazolyl)-7-(diethylamino)coumarin, coumarin 6

(3) thermosetting resin

Daicel Corporation, EHPE3150 (polyfunctional alicyclic epoxy resin, 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol)

(4) photopolymerizable monomer

Made by Toa Synthetic, Aronix (registered trademark) M-402 (multifunctional acrylate, dipentaerythritol penta, and hexaacrylate)

(5) photopolymerization initiator

BASF, Irgacure (registered trademark) OXE02 (oxime ester photopolymerization initiator)

(6) solvent

Propylene glycol monomethyl ether acetate (PMA)

Fluorescence spectra of the quantum dot dispersion liquid and the fluorescent dye dispersion (dispersion medium: PMA, fluorescent dye concentration: 0.01% by weight) used in the examples were measured with a spectroscopic fluorescence photometer described later. In addition, the absorption spectrum was measured by Hitachi Hi-Tech Science Co., Ltd. product, spectrophotometer, and F-7000. Each measurement value of fluorescence intensity and absorbance was normalized using the peak value at 430 to 550 nm. The results are shown in Figs. 2A and 2B. As shown in Fig. 2A, the quantum dot has a bottom at a wavelength of 460 nm and a peak at a wavelength of 495 nm, and the fluorescent dye has two peaks between a wavelength of 440 nm and 460 nm. In addition, as can be seen from Fig. 1(a), for normalization of the absorption spectrum of the fluorescent dye, the absorbance of the larger of the two peaks was used. As shown in (b) of FIG. 2, the quantum dot has a peak at a wavelength of 530 nm, and the fluorescent dye has a peak at a wavelength of 495 nm. In addition, the half width of the wavelength at the fluorescence intensity of 50 was 39 nm for the quantum dots and 62 nm for the fluorescent dye, so the half width of the fluorescent dye was 1.6 times the half width of the quantum dots.

(Example 1)

<Preparation of quantum dot dispersion>

Mixing 20 parts by weight of a quantum dot dispersion (quantum dot: 2 parts by weight), 0.023 parts by weight of a fluorescent dye, 9.5 parts by weight of the light scattering agent dispersion of Preparation Example 1, and 47.9 parts by weight of an acrylic resin (solid content 9.58 parts by weight) of Preparation Example 2 And dispersed so as to become uniform, thereby obtaining a quantum dot dispersion.

<Preparation of composition for coating film formation>

The obtained quantum dot dispersion was mixed with 2.2 parts by weight of a thermosetting resin, 5.4 parts by weight of a photopolymerizable monomer, 0.9 parts by weight of a photopolymerization initiator, and 14.08 parts by weight of a solvent were mixed, dispersed so as to be uniform, and filtered through a 1 µm filter to form a coating film. The composition was obtained.

<Production of coating>

The obtained composition for coating film formation was applied to a glass substrate by spin coating and dried at 70° C. for 1 minute, and then 100 mJ/cm 2 of light from a high-pressure mercury lamp was irradiated through a photomask having a stripe pattern of 50 μm. Development was performed for 80 seconds with an alkaline developer. Then, it heat-drying|processed at 180 degreeC for 20 minutes, and obtained the coating film (cured film) from the composition for coating film formation.

In addition, the component composition of the alkaline developer used to prepare a coating film is as follows.

·Sodium carbonate 1.5% by mass

·Sodium hydrogen carbonate 0.5% by mass

・Anionic surfactant (Kao Perrelex NBL) 8.0% by mass

·water 90.0% by mass

(evaluation)

<Patternability evaluation>

The obtained coating film (cured film) was observed using an optical microscope (manufactured by Nikon, product name ECLIPSE LV100, magnification 200 times). A case in which there was no developing residue and there was no appearance abnormality such as pixel roughness or cracking in the pattern was judged as good patterning property, and a case where there was a developing residue and/or the above appearance abnormality was judged as poor patterning property.

<Measurement of fluorescence intensity and half width (FWHM)>

About the obtained coating film (cured film), the fluorescence spectrum was measured using the Hitachi Hi-Tech Science Co., Ltd. make, spectroscopic fluorescence photometer, F-7000, and the fluorescence intensity and half width of the peak at a wavelength of 500 to 600 nm were calculated. The fluorescence intensity was calculated using the value of Comparative Example 1 as a reference (100%).

<Measurement of optical density (OD)>

About the obtained coating film (cured film), optical density was measured using the Konica Minolta Sensing Co., Ltd. product, a spectroradiometer, CS-1000.

(Example 2, Comparative Examples 1 to 4)

A composition for forming a coating film was prepared after preparing a quantum dot dispersion in the same manner as in Example 1 except that the component composition shown in Table 1 was obtained. Using the obtained composition for coating film formation, it carried out similarly to Example 1, produced the coating film (cured film), and evaluated.

Table 1 shows the component composition and evaluation results of the quantum dot dispersions and coating film-forming compositions of Examples 1 and 2 and Comparative Examples 1 to 4. In addition, the fluorescence spectrum of each coating film (cured film) is shown in FIG. In Fig. 3, a large peak is seen at a wavelength of 448 nm, but this is due to the light source. As shown in Fig. 3, the fluorescence spectrum of the coating film (cured film) has substantially the same spectrum in Examples 1 and 2 at a wavelength of 500 to 600 nm, and a single peak is observed in both. In the same wavelength range, Comparative Example 4 has a smaller half width than Examples 1 and 2, but has a smaller light emission intensity. In Comparative Examples 1 to 3, in the same wavelength range, the emission intensity of the peak is considerably small. In addition, the blank is a result of measuring a glass substrate to which the composition for coating film formation was not applied as a sample.

As shown in Fig. 2, the quantum dots and fluorescent dyes used in Examples 1 and 2 have specific spectra. And, by using such a quantum dot and a fluorescent dye in combination with a light scattering agent, as shown in Table 3, it is possible to suppress an increase in the half value width caused by the fluorescent dye and to improve the fluorescence intensity, and the apparent concentration ( It can be seen that it is possible to improve the OD value). In addition, from the fluorescence spectrum shown in Fig. 2(b), a broad fluorescence peak is expected in the spectrum of the coating film (cured film), but as shown in Fig. 3, the increase in the half-width is significantly suppressed, indicating that the single peak is Able to know.

LA1: Line indicating the position of the wavelength A1 at the bottom of the absorption spectrum of the quantum dot
LA2: Line indicating the position of wavelength A2 of the peak of the absorption spectrum of the quantum dot
LA3: Line indicating the position of wavelength A3 of excitation light of fluorescent dye
LA4: A line indicating the position of the wavelength A4 represented by the equal sign in Equation (1)
L1: half width of the peak of emission of the fluorescence spectrum of the fluorescent dye
L2: the region of the wavelength at which the peak wavelength A5 of the emission of the fluorescence spectrum of the fluorescent dye exists

Claims (5)

As a quantum dot dispersion comprising a quantum dot, a light scattering agent, a fluorescent dye and a solvent,
The quantum dot has an absorption spectrum in which a bottom exists in a region with a wavelength of 480 nm or less and a peak is present in a region with a wavelength greater than 480 nm, and a fluorescence spectrum in which a peak exists in a region with a wavelength of 495 to 570 nm. Has,
In the fluorescent dye, a peak of fluorescence emission exists between the wavelength A1 of the bottom of the quantum dot and the wavelength A2 of the peak of the absorption spectrum, and the half width of the peak of the fluorescence emission is the fluorescence spectrum of the quantum dot Quantum dot dispersion having a fluorescence spectrum less than twice the half width of the peak of. The method according to claim 1, wherein the fluorescent dye absorbs the excitation light of a wavelength A3 on the lower wavelength side than the wavelength A1, and in the fluorescence spectrum, the following formula (1) is the wavelength A2 and the wavelength longer than the wavelength A1. A quantum dot dispersion that emits fluorescence in which a peak exists at a wavelength A5 that satisfies the following equation (2) at a wavelength between the wavelength A4 that satisfies the relationship of ).
A4=A1+(A1-A3)<A2 (1)
A4≤A5≤A2 (2) The quantum dot dispersion according to claim 1 or 2, wherein the light scattering agent is at least one selected from metal compounds. The quantum dot dispersion according to any one of claims 1 to 3, wherein the fluorescent dye is at least one selected from coumarin-based dyes. A composition for forming a coating film comprising the quantum dot dispersion according to any one of claims 1 to 4 and a coating film forming component.

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