Luminescent particle, ink composition, light conversion layer, wavelength conversion film, and color filter

Abstract

To provide a luminescent particle containing nanocrystals that exhibits superior stability to water, light, and heat, an ink composition containing the luminescent particle, a light conversion layer composed of a cured product of the ink composition, and a wavelength conversion film and a color filter including the light conversion layer.SOLUTION: A luminescent particle has a surface layer on a semiconductor nanocrystal particle composed of a metal halide. The surface layer contains a hydrolytic condensate of a T-unit silane compound and a hydrolytic condensate of a Q-unit silane compound. The luminescent particle contains 50 mass% or more and 70 mass% or less of organic components as determined by thermogravimetry differential thermal analysis.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to luminescent particles, an ink composition, a light conversion layer, a wavelength conversion film, and a color filter.

Background Art

[0002] In recent years, quantum dots having a perovskite structure, which are a kind of semiconductor nanocrystals composed of metal halides, have been discovered (for example, Patent Document 1). Perovskite quantum dots are semiconductor nanocrystals represented by, for example, CsPbX3 (X represents Cl, Br, or I), and the emission wavelength can be controlled by adjusting the particle size, the type and the abundance ratio of halogen atoms. Since the operation of the adjustment is simple, perovskite quantum dots can more easily control the emission wavelength compared with core-shell type quantum dots typified by CdSe / ZnS, and thus have the advantage of excellent productivity. Further, since perovskite quantum dots have a high photoluminescence quantum (PLQY) and a narrow emission wavelength width (FWHM), they are being studied for use in light conversion layers such as wavelength conversion films and color filters for backlights of liquid crystal displays as quantum dots to replace CdSe-based materials.

[0003] While perovskite quantum dots have excellent optical properties, improvement in stability against moisture, light, and heat is required. For example, a technique has been proposed in which a silica layer is formed on the surface of perovskite quantum dot particles using a silane compound such as 3-aminopropyltriethoxysilane to enhance stability (Non-Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Non-Patent Documents

[0005]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, according to the method disclosed in Non-Patent Document 1, when forming a silica layer on the surface of nanocrystals using a silane compound, water molecules involved in the hydrolysis of the silane compound and the alcohol generated during hydrolysis easily cause deterioration of perovskite quantum dots, resulting in disadvantages such as poor dispersibility due to particle aggregation and insufficient optical properties such as quantum yield and full width at half maximum due to the generation of defect levels on the particle surface. Furthermore, when the luminescent particles containing the nanocrystals obtained in Non-Patent Document 1 are used as a light conversion layer, there is a disadvantage that the optical properties deteriorate due to the halogen desorption of the nanocrystals constituting the perovskite quantum dots caused by the light and heat of the backlight.

[0007] An object of the present invention is to provide luminescent particles containing nanocrystals, which are excellent in stability against water, light, and heat. Another object of the present invention is to provide an ink composition containing such luminescent particles, a light conversion layer composed of a cured product of the ink composition, a wavelength conversion film provided with the light conversion layer, and a color filter.

Means for Solving the Problems

[0008] As a result of intensive studies, the present inventors have found that in luminescent particles containing semiconductor nanocrystals composed of metal halides and having luminescence properties, when containing a hydrolysis condensate of a silane compound of T unit and Q unit and containing 50% by mass or more and 70% by mass or less of an organic component calculated by thermogravimetric differential thermal analysis, excellent dispersion stability, excellent optical properties, and durability can be obtained, and thus the present invention has been conceived.

[0009] That is, the luminescent particles of the present invention are luminescent particles having a surface layer on semiconductor nanocrystal particles composed of metal halide, wherein the surface layer contains a hydrolysis condensate of a silane compound of T unit and a hydrolysis condensate of a silane compound of Q unit, and the luminescent particles contain 50% by mass or more and 70% by mass or less of an organic component calculated by thermogravimetric differential thermal analysis.

[0010] The ink composition of the present invention is characterized by containing the above luminescent particles, a photopolymerizable compound, and a photopolymerization initiator.

[0011] The light conversion layer of the present invention is characterized by containing a polymer of the above ink composition.

[0012] The wavelength conversion film of the present invention is characterized by including the above light conversion layer.

[0013] The color filter of the present invention is characterized by including the above light conversion layer.

Advantages of the Invention

[0014] According to one aspect of the present invention, it is possible to provide luminescent particles using semiconductor nanocrystal particles composed of metal halide, which are excellent in dispersibility and stability, an ink composition containing the luminescent particles, a light conversion layer, a wavelength conversion film, and a color filter.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described. The present invention is not limited to the following embodiments.

[0017] 1. Luminescent particles The luminescent particles of the present invention have a surface layer on a semiconductor nanocrystal composed of a metal halide, and the surface layer contains a hydrolysis condensate of a silane compound of the T unit and a hydrolysis condensate of a silane compound of the Q unit, and contains 50% by mass or more and 70% by mass or less of an organic component calculated by thermogravimetric differential thermal analysis.

[0018] The luminescent particles in the present invention can be suitably used, for example, in an ink composition for forming a light conversion layer such as a wavelength conversion film. Such an ink composition is excellent in the dispersion stability of the luminescent particles and has excellent optical physical properties.

[0019] The reason for obtaining the above effects is not clear, but the present inventors speculate as follows.

[0020] In the luminescent particles having a surface layer on a semiconductor nanocrystal composed of a metal halide of the present invention, the surface layer contains both a hydrolysis condensate of a silane compound of the T unit and a hydrolysis condensate of a silane compound of the Q unit, and contains 50% by mass or more of an organic component calculated from thermogravimetric differential thermal analysis. As a result, in the luminescent particles of the present invention, while forming a strong surface layer, the aggregation of the luminescent particles can be suppressed by the presence of the organic component. Therefore, the luminescent particles in the present invention can suppress their aggregation and obtain excellent dispersibility. In addition, in a light conversion layer formed from an ink composition containing the luminescent particles of the present invention, changes over time in optical properties such as emission peak wavelength, full width at half maximum, and quantum yield (PLQY, IQE) can be suppressed.

[0021] On the other hand, in the case where the surface layer of the luminescent particles contains a hydrolysis condensate of a silane compound having a T unit but does not contain a hydrolysis condensate of a silane compound having a Q unit, since the surface layer is not strong, ligand detachment from the semiconductor nanocrystal surface and decomposition of the semiconductor nanocrystal are likely to occur due to water, light, and heat. Further, in the case where the surface layer contains a hydrolysis condensate of a silane compound having a Q unit but does not contain a hydrolysis condensate of a silane compound having a T unit, although the surface layer is strong, aggregation between the luminescent particles is likely to occur and the dispersion stability becomes insufficient.

[0022] As described above, according to the present invention, excellent dispersibility of the luminescent particles can be obtained, and a light conversion layer having excellent stability against water, light, and heat can be obtained from the ink composition. Such an effect is preferably exhibited during UV irradiation at the time of curing and during long-term lighting of the backlight.

[0023] An embodiment of the luminescent particles of the present invention is shown in FIG. 1, but the embodiment is not limited thereto.

[0024] The luminescent particles 10 shown in FIG. 1 include a semiconductor nanocrystal 11 made of a metal halide and a surface layer 12 covering the surface of the semiconductor nanocrystal 11. The surface layer 12 contains a hydrolysis condensate of a silane compound having a T unit and a hydrolysis condensate of a silane compound having a Q unit, and contains 50% by mass or more and 70% by mass or less of an organic component calculated from thermogravimetric differential measurement.

[0025] 1-1. Semiconductor Nanocrystal The luminescent particles of the present invention include a luminescent semiconductor nanocrystal and can emit light (fluorescence or phosphorescence) having a wavelength different from the absorbed wavelength by absorbing light having a predetermined wavelength. Here, the luminescence property is preferably a property of emitting light by excitation of electrons, and more preferably a property of generating luminescence when electrons contained in the nanocrystal are excited from the ground state to the excited state and return to the ground state when excitation light is irradiated.

[0026] <Semiconductor Nanocrystal Made of Metal Halide> In the present invention, the semiconductor nanocrystal is a semiconductor nanocrystal composed of a metal halide (hereinafter, may be simply referred to as "nanocrystal"), and is a nanosized crystal (nanocrystal particle) that absorbs excitation light and emits fluorescence or phosphorescence. Such a nanocrystal is, for example, a crystal having a maximum particle diameter of 100 nm or less measured by a transmission electron microscope or a scanning electron microscope. The nanocrystal can be excited by, for example, light energy or electrical energy of a predetermined wavelength and emit fluorescence or phosphorescence. Further, a nanocrystal which is a quantum dot composed of a metal halide can obtain emission with a narrower full width at half maximum.

[0027] In the luminescent particle of the present invention, the semiconductor nanocrystal has the general formula A a M b X c is a compound represented by Here, a is a positive number from 1 to 7, b is a positive number from 1 to 4, and c is a positive number from 1 to 16.

[0028] In the above formula, A represents a monovalent cation and is at least one of an organic cation and a metal cation. Examples of the organic cation include one or more selected from the group consisting of methylammonium, formamidinium, ammonium, 2-phenylethylammonium, pyrrolidinium, piperidinium, 1-butyl-1-methylpiperidinium, tetramethylammonium, tetraethylammonium, benzyltrimethylammonium, benzyltriethylammonium, guanidinium, imidazolium, pyridinium, and protonated thiourea. Examples of the metal cation include monovalent cations such as Cs, Rb, K, Na, and Li.

[0029] M represents at least one kind of metal cation. Specifically, one kind of metal cation (M1), two kinds of metal cations (M 1α M 2β ), three kinds of metal cations (M 1α M 2β M 3γ ), four kinds of metal cations (M 1α M 2β M 3γ M 4δ) etc. are included. However, α, β, γ, and δ each represent a real number from 0 to 1, and α + β + γ + δ = 1. Examples of the metal cation represented by M include metal cations selected from Group 1, Group 2, Group 3, Group 4, Group 5, Group 6, Group 7, Group 8, Group 9, Group 10, Group 11, Group 13, Group 14, and Group 15. More preferably, cations such as Ag, Au, Bi, Ca, Ce, Co, Cr, Cu, Eu, Fe, Ga, Ge, Hf, In, Ir, Mg, Mn, Mo, Na, Nb, Nd, Ni, Os, Pb, Pd, Pt, Re, Rh, Ru, Sb, Sc, Sm, Sn, Sr, Ta, Te, Ti, V, W, Zn, Zr, etc. are included.

[0030] X represents an anion containing at least one kind of halogen, specifically, it contains one kind or two or more kinds of halide anions. When two or more anions coexist as X, there is no particular limitation on the coexistence ratio. Examples of such anions include F - , Cl - , Br - , I - and other halide ions.

[0031] The general formula A a M b X c Specific examples of the compound represented by are AMX, A4MX, AMX2, AMX3, A2MX3, AM2X3, A2MX4, A2MX5, A3MX5, A3M2X5, A3MX6, A4MX6, AM2X6, A2MX6, A4M2X6, A3MX8, A3M2X9, A3M3X9, A2M2X 10 , A7M3X 16 Compounds represented by are preferred.

[0032] The general formula A a M b X cAmong the compounds composed of metal halides represented by [formula], compounds having a perovskite crystal structure are particularly preferable for use as semiconductor nanocrystals in that the emission wavelength (emission color) can be controlled by adjusting the particle size, the type and abundance ratio of the metal cations constituting the M site, and further adjusting the type and abundance ratio of the anions constituting the X site. Specifically, compounds represented by AMX3, A3MX5, A3MX6, A4MX6, and A2MX6 are preferable. A, M, and X in the formula are as described above. Further, the compound having a perovskite crystal structure may be one doped with metal ions such as Bi, Mn, Ca, Eu, Sb, and Yb as described above.

[0033] Among the compounds showing a perovskite crystal structure, from the viewpoints of ease of synthesis, good luminescence properties, and robustness of the crystal structure, A is preferably a cation selected from the group consisting of Cs, Rb, K, Na, Li, methylammonium, and formamidinium, more preferably a cation selected from Cs, Rb, methylammonium, and formamidinium, and even more preferably a cation selected from Cs and formamidinium. From the viewpoints of ease of synthesis, good luminescence properties, and robustness of the crystal structure, M is preferably a metal ion selected from the group consisting of Pb, Sn, Ge, Bi, Sb, Ag, In, Cu, Yb, Ti, Pd, Mn, Eu, Zr, and Tb, more preferably a metal ion selected from the group consisting of Pb, Sn, Bi, Sb, Ag, In, Cu, Mn, and Zr, even more preferably a metal ion selected from the group consisting of Pb, Sn, and Cu, and particularly preferably a Pb ion. X is preferably a halide ion selected from the group consisting of F−, Cl−, Br−, and I−. From the viewpoints of ease of synthesis, good luminescence properties, and robustness of the crystal structure, a halide ion selected from the group consisting of Cl−, Br−, and I− is more preferable, a halide ion selected from the group consisting of Br− and I− is even more preferable, and Br− is particularly preferable.

[0034] As specific compositions of nanocrystals having a perovskite crystal structure, nanocrystals using Pb as M, such as CsPbBr3, (CH3NH3)PbBr3, (CHN2H4)PbBr3, CsPbI3, (CH3NH3)PbI3, (CHN2H4)PbI3, CsPb(Br / I)3, (CH3NH3)Pb(Br / I)3, (CHN2H4)Pb(Br / I)3, etc., are preferable because they have excellent light intensity and excellent quantum efficiency. Also, CsSnBr3, CsSnCl3, CsSnBr 1.5 Cl 1.5 , Cs3Sb2Br9, (CH3NH3)3Bi2Br9, (C4H9NH3)2AgBiBr6, etc., nanocrystals using metal cations other than Pb as M are preferable because they are low in toxicity and have little impact on the environment.

[0035] As nanocrystals, red light-emitting crystals that emit light (red light) having an emission peak in the wavelength range of 605 to 665 nm, green light-emitting crystals that emit light (green light) having an emission peak in the wavelength range of 500 to 560 nm, blue light-emitting crystals that emit light (blue) having an emission peak in the wavelength range of 420 to 480 nm, etc. can be selected and used. Note that the wavelength of the emission peak of the nanocrystals can be confirmed in, for example, the fluorescence spectrum or phosphorescence spectrum measured using an absolute PL quantum yield measurement device.

[0036] The red light-emitting nanocrystals preferably have an emission peak in the wavelength range of 665 nm or less, 663 nm or less, 660 nm or less, 658 nm or less, 655 nm or less, 653 nm or less, 651 nm or less, 650 nm or less, 647 nm or less, 645 nm or less, 643 nm or less, 640 nm or less, 637 nm or less, 635 nm or less, 632 nm or less, or 630 nm or less, and preferably have an emission peak in the wavelength range of 628 nm or more, 625 nm or more, 623 nm or more, 620 nm or more, 615 nm or more, 610 nm or more, 607 nm or more, or 605 nm or more. These upper and lower limit values can be arbitrarily combined. In the following similar descriptions as well, the individually described upper and lower limit values can be arbitrarily combined.

[0037] The green-emitting nanocrystals preferably have an emission peak in a wavelength range of 560 nm or less, 557 nm or less, 555 nm or less, 550 nm or less, 547 nm or less, 545 nm or less, 543 nm or less, 540 nm or less, 537 nm or less, 535 nm or less, 532 nm or less, or 530 nm or less, and preferably have an emission peak in a wavelength range of 528 nm or more, 525 nm or more, 523 nm or more, 520 nm or more, 515 nm or more, 510 nm or more, 507 nm or more, 505 nm or more, 503 nm or more, or 500 nm or more.

[0038] The blue-emitting nanocrystals preferably have an emission peak in a wavelength range of 480 nm or less, 477 nm or less, 475 nm or less, 470 nm or less, 467 nm or less, 465 nm or less, 463 nm or less, 460 nm or less, 457 nm or less, 455 nm or less, 452 nm or less, or 450 nm or less, and preferably have an emission peak in a wavelength range of 450 nm or more, 445 nm or more, 440 nm or more, 435 nm or more, 430 nm or more, 428 nm or more, 425 nm or more, 422 nm or more, or 420 nm or more.

[0039] The shape of the nanocrystals is not particularly limited and may be any geometric shape or any irregular shape. Examples of the shape of the nanocrystals include a rectangular parallelepiped shape, a cubic shape, a spherical shape, a regular tetrahedral shape, an ellipsoidal shape, a pyramidal shape, a disk shape, a dendritic shape, a network shape, a rod shape, etc. The shape of the nanocrystals is preferably a rectangular parallelepiped shape, a cubic shape, or a spherical shape.

[0040] The average particle diameter (volume average diameter) of the nanocrystals is preferably 40 nm or less, more preferably 30 nm or less, still more preferably 20 nm or less, and particularly preferably 15 nm or less. Also, the average particle diameter of the nanocrystals is preferably 1 nm or more, more preferably 1.5 nm or more, still more preferably 2 nm or more, and particularly preferably 3 nm or more. Nanocrystals having such an average particle diameter can obtain a desired emission wavelength, suppress the formation of secondary particles due to aggregation of the nanocrystals, and suppress a decrease in fluorescence quantum yield, luminance, and color reproducibility. Note that the average particle diameter of the nanocrystals is obtained by measuring the particle diameter of the nanocrystals using a transmission electron microscope (TEM), a scanning electron microscope (SEM), an X-ray diffractometer (XRD), etc., and calculating the average particle diameter based on volume.

[0041] 1-2. Surface layer The luminescent particles of the present invention are provided with a surface layer containing a hydrolysis condensate of a silane compound of the T unit, a hydrolysis condensate of a silane compound of the Q unit, and an organic component on the surface of the semiconductor nanocrystals. Such a surface layer may be composed of a single layer or a plurality of layers. By providing the nanocrystals with the surface layer, the stability of the luminescent particles against moisture and oxygen, light resistance, etc. can be improved. Further, it is preferable from the viewpoint of improving the durability of the optical properties of the light conversion layer formed from the ink composition containing the luminescent particles of the present invention.

[0042] [Silane compound] Generally, silicon atoms contained in the hydrolysis condensate of a silane compound are called and distinguished as an M unit for a silicon atom bonded to one oxygen atom, a D unit for a silicon atom bonded to two oxygen atoms, a T unit for a silicon atom bonded to three oxygen atoms, and a Q unit for a silicon atom bonded to four oxygen atoms. Examples of the M unit, D unit, T unit, and Q unit can be the following formulas (M), (D), (T), and (Q), respectively.

[0043] [Chemical formula] In the above formulas, R is a substituent bonded to silicon, and for example, each independently, it is a hydrogen atom, a hydroxy group, a carboxyl group, an amino group, a mercapto group, an acrylic group, a methacrylic group, an acryloyl group, a methacryloyl group, an isocyanate group, a cyclic ether group, or a monovalent hydrocarbon group, and a hydrogen atom in the monovalent hydrocarbon group may be substituted with a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom.

[0044] Information on the content of substituents bonded to silicon can be obtained by 29Si-NMR. In the 29Si-NMR spectrum, the chemical shift of the M unit is confirmed in the range of about -81 ppm to about -90 ppm, the chemical shift of the D unit is confirmed in the range of about -90 ppm to about -95 ppm, the chemical shift of the T unit is confirmed in the range of about -98 ppm to about -104 ppm, and the chemical shift of the Q unit is confirmed in the range of about -108 ppm to about -111 ppm. However, the ranges of these chemical shifts may generally include an error of about ±3 ppm.

[0045] <Silane compound of T unit> The silane compound of the T unit used in the luminescent particles of the present invention is preferably a compound represented by the following general formula (T1).

[0046]

Chemical formula

[0047] When a compound represented by the general formula (T1) is used as a ligand capable of coordinating to the surface of a nanocrystal, such a ligand preferably has a bonding group that binds to a cation or an anion contained in the nanocrystal and a reactive group capable of forming a siloxane bond by hydrolysis. As the reactive group capable of forming a siloxane bond in the silane compound of the T unit used as a ligand (hereinafter also referred to as "silane ligand T"), from the viewpoint of easily forming a siloxane bond, a hydrolyzable silyl group such as a silanol group or an alkoxysilyl group having 1 to 6 carbon atoms is preferable, and a silanol group or an alkoxysilyl group having 1 to 2 carbon atoms is more preferable. As the bonding group of the silane ligand T, at least one of a hydroxy group, a carboxyl group, an amino group, and a mercapto group is preferable, and at least one of an amino group and a mercapto group is more preferable. Since these bonding groups have a high affinity for the cation or anion contained in the nanocrystal, the silane ligand T coordinates with the bonding group facing the nanocrystal side. Then, by forming a siloxane bond by condensation of the hydrolyzable silyl group of the silane ligand T, a surface layer including a structure having a siloxane bond can be formed more easily and surely. As the silane ligand T, an amino group-containing silane compound and a mercapto group-containing silane compound are particularly preferable. These may be used alone or in combination of two or more.

[0048] Examples of the amino group-containing silane compound include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltripropoxysilane, N-(2-aminoethyl)-3-aminopropyltriisopropoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, (aminoethylaminoethyl)phenyltrimethoxysilane, (aminoethylaminoethyl)phenyltriethoxysilane, (aminoethylaminoethyl)phenyltripropoxysilane, (aminoethylaminoethyl)phenyltriisopropoxysilane, (aminoethylaminomethyl)phenyltrimethoxysilane, (aminoethylaminomethyl)phenyltriethoxysilane, (aminoethylaminomethyl)phenyltripropoxysilane, (aminoethylaminomethyl)phenyltriisopropoxysilane, 3-ureidopropyltriethoxysilane, 3-(N-phenyl)aminopropyltrimethoxysilane, N,N-bis[3-(trimethoxysilyl)propyl]ethylenediamine, (aminoethylaminoethyl)phenethyltrimethoxysilane, (aminoethylaminoethyl)phenethyltriethoxysilane, (aminoethylaminoethyl)phenethyltripropoxysilane, (aminoethylaminoethyl)phenethyltriisopropoxysilane, (aminoethylaminomethyl)phenethyltrimethoxysilane, (aminoethylaminomethyl)phenethyltriethoxysilane, (aminoethylaminomethyl)phenethyltripropoxysilane, (aminoethylaminomethyl)phenethyltriisopropoxysilane, N-[2-[3-(trimethoxysilyl)propylamino]ethyl]ethylenediamine, N-[2-[3-(triethoxysilyl)propylamino]ethyl]ethylenediamine, N-[2-[3-(tripropoxysilyl)propylamino]ethyl]ethylenediamine, N-[2-[3-(triisopropoxysilyl)propylamino]ethyl]ethylenediamine, and the like.

[0049] Examples of the mercapto group-containing silane compound include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and the like.

[0050] In addition to the silane compound of the T unit used in the luminescent particles of the present invention (silane ligand T) that functions as a ligand, from the viewpoint of being able to compensate for the halogen desorbed from the nanocrystal by light or heat, it is preferable to further contain a halogenated alkoxysilane compound. Examples of the halogenated alkoxysilane compound include 3-bromopropyltrimethoxysilane, 3-bromopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3-iodopropyltrimethoxysilane, 3-iodopropyltriethoxysilane, and the like. The halogen species in the halogenated alkoxysilane compound is preferably the same as the halogen species constituting the nanocrystal for the purpose of imparting excellent optical properties. For example, when the halogen species in the nanocrystal is bromine, a brominated alkoxysilane compound is preferable, and 3-bromopropyltrimethoxysilane is more preferable.

[0051] <Silane compound of the Q unit> The silane compound of the Q unit used in the luminescent particles of the present invention is preferably a compound represented by the following general formula (Q1).

[0052] [Chemical formula] In the above formula, R Q1 and R Q2 each independently represent an alkyl group having 1 to 4 carbon atoms, and R Q3 and R Q4 each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and m represents an integer of 1 or more and 10 or less.

[0053] The compound represented by the formula (Q1) is specifically, for example, tetrabutoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, phenyltrimethoxysilane, vinyltriethoxysilane, n-propyltrimethoxysilane, isopropyltrimethoxysilane, n-butyltriethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane, n-dodecyltrimethoxysilane, n-dodecyltriethoxysilane, n-hexadecyltrimethoxysilane, n-hexadecyltriethoxysilane, n-octadecyltrimethoxysilane, trimethoxy(3,3,3-trifluoropropyl)silane, trimethoxy(pentafluorophenyl)silane, trimethoxy(11-pentafluorophenoxyundecyl)silane, trimethoxy(1H,1H,2H,2H-nonafluorohexyl)silane, a partially hydrolyzed oligomer of tetramethoxysilane (product name: methyl silicate 51, methyl silicate 53A (both manufactured by Colcoat Co., Ltd.)), a partially hydrolyzed oligomer of tetraethoxysilane (product name: ethyl silicate 40, ethyl silicate 48 (both manufactured by Colcoat Co., Ltd.)), a partially hydrolyzed oligomer of a mixture of tetramethoxysilane and tetraethoxysilane (product name: EMS-485 (manufactured by Colcoat Co., Ltd.)), and the like.

[0054] From the viewpoint of the robustness of the hydrolysis condensate, in the general formula (Q1), R Q1 and R Q2 are each independently preferably an alkyl group having 1 to 2 carbon atoms, and R Q3 and R Q4 are each independently preferably a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, and m is preferably an integer of 1 or more and 4 or less.

[0055] In addition to the silane compounds of the T unit and the Q unit, the silane compound for forming the surface layer of the luminescent particles of the invention can also be used in combination with, for example, the compound represented by the following formula (C2) and the silane compound represented by (C3).

[0056] [Chemical formula] In the formula, R C21 , R C22 , R C31 each independently represents an alkyl group, and R C23 , R C24 , R C32 , R C33 , and R C34 each independently represents a hydrogen atom, an alkyl group which may have a substituent, a phenyl group, or a cyclohexyl group. The carbon atom in the alkyl group may be substituted with an oxygen atom or a nitrogen atom, and m2 represents an integer of 1 or more and 10 or less.

[0057] Specific examples of the compound represented by the formula (C2) and the compound represented by the formula (C3) include, for example, dimethyldiethoxysilane, diphenyldimethoxysilane, methylethyldimethoxysilane, and trimethylmethoxysilane. The compound represented by the formula (C2) and the compound represented by (C3) may be used in combination of one or more in addition to the compounds represented by the general formulas (T1) and (Q1) within the range that can maintain the excellent optical properties and durability of the luminescent particles.

[0058] The hydrolytic condensate of the silane compound contained in the surface layer of the luminescent particles of the present invention preferably contains only the hydrolytic condensate of the silane compound of the T unit and the hydrolytic condensate of the silane compound of the Q unit from the viewpoint of maintaining the excellent optical properties and durability of the luminescent particles. In the 29Si-NMR spectrum, when the percentage of the area of the silicon atoms contained in the hydrolytic condensate of the silane compound of the T unit is Si(T) and the percentage of the area of the silicon atoms contained in the hydrolytic condensate of the silane compound of the Q unit is Si(Q), from the viewpoints of the monomer dispersibility of the luminescent particles and the durability of the cured product formed from the ink composition containing the luminescent particles, Si(T) / Si(Q) is preferably 0.30 to 0.70, and more preferably 0.40 to 0.60.

[0059] [Organic component] The organic component contained in the luminescent particles of the present invention includes a compound having no Si atom capable of binding to the surface of the nanocrystal constituting the luminescent particle (hereinafter also referred to as "ligand") and a polymer. This organic component not only has excellent affinity for the luminescent particles but also has excellent affinity for the photopolymerizable compound. Therefore, it can exist without forming aggregates in the ink composition containing the luminescent particles of the present invention, and thus the composition has excellent dispersion stability.

[0060] Further, as the organic component, a salt composed of a monovalent cation and a halogen the same as the nanocrystal constituting the luminescent particle may be included. By including the salt in the luminescent particles, more excellent light resistance can be obtained when a light conversion layer described later is formed.

[0061] The mass ratio of the organic component contained in the luminescent particles of the present invention can be determined by performing thermogravimetric analysis using a thermogravimetric differential thermal analyzer (TG-DTA). The mass ratio of the organic component is calculated from the weight loss rate at 470°C when the luminescent particles of the present invention are subjected to thermogravimetric analysis. The weight loss rate at 470°C is obtained from the weight of the sample (luminescent particles) before measurement and the weight of the sample at 470°C in the thermogravimetric analysis by the following formula (I). Weight loss rate (%) at 470 °C (mass ratio of the organic component in the luminescent particles) = 100 × (weight of the sample before the test - weight of the sample at 470 °C) / weight of the sample before the measurement ··· Formula (I)

[0062] The mass ratio of the organic component is preferably 50% by mass or more and 70% by mass or less. When the weight loss rate is 50% by mass or less, the dispersibility when made into an ink composition becomes insufficient, and when the weight loss rate is 70% by mass or more, the durability of the cured product formed from the ink composition becomes insufficient. From such a viewpoint, the above weight loss rate is preferably 55% by mass or more and 70% by mass or less, and more preferably 60% by mass or more and 70% by mass or less.

[0063] The ligand is not particularly limited as long as it is a compound having a site capable of binding to the surface of the nanocrystal. Specifically, for example, as the site capable of binding, for example, at least one of a carboxyl group, a carboxylic anhydride group, an amino group, an ammonium group, a mercapto group, a phosphine group, a phosphine oxide group, a phosphate group, a phosphonic acid group, a phosphinic acid group, a sulfonic acid group, and a boronic acid group is preferably used, and at least one of a carboxyl group and an amino group is more preferably used. Examples of such a ligand include a carboxyl group- or amino group-containing compound, etc., and one of these can be used alone, or two or more thereof can be used in combination.

[0064] Examples of the carboxyl group-containing compound include linear or branched aliphatic carboxylic acids having 1 to 30 carbon atoms. Specific examples of such carboxyl group-containing compounds include, for example, arachidonic acid, crotonic acid, trans-2-decenoic acid, erucic acid, 3-decenoic acid, cis-4,7,10,13,16,19-docosahexaenoic acid, 4-decenoic acid, all cis-5,8,11,14,17-eicosapentaenoic acid, all cis-8,11,14-eicosatrienoic acid, cis-9-hexadecenoic acid, trans-3-hexenoic acid, trans-2-hexenoic acid, 2-heptenoic acid, 3-heptenoic acid, 2-hexadecenoic acid, linolenic acid, linoleic acid, γ-linolenic acid, 3-nonenoic acid, 2-nonenoic acid, trans-2-octenoic acid, petroselinic acid, elaidic acid, oleic acid, 3-octenoic acid, trans-2-pentenoic acid, trans-3-pentenoic acid, ricinoleic acid, sorbic acid, 2-tridecenoic acid, cis-15-tetracosenic acid, 10-undecenoic acid, 2-undecenoic acid, acetic acid, butyric acid, behenic acid, cerotic acid, decanoic acid, arachidic acid, heneicosanoic acid, heptadecanoic acid, heptanoic acid, hexanoic acid, heptacosaanoic acid, lauric acid, myristic acid, melissic acid, octacosaanoic acid, nonadecanoic acid, nonacosaanoic acid, n-octanoic acid, palmitic acid, pentadecanoic acid, propionic acid, pentacosaanoic acid, nonanoic acid, stearic acid, lignoceric acid, tricosanoic acid, tridecanoic acid, undecanoic acid, valeric acid, etc.

[0065] Examples of the amino group-containing compound include linear or branched aliphatic amines having 1 to 30 carbon atoms. Specific examples of such amino group-containing compounds include, for example, 1-aminoheptadecane, 1-aminononadecane, heptadecane-9-amine, stearylamine, oleylamine, 2-n-octyl-1-dodecylamine, allylamine, amylamine, 2-ethoxyethylamine, 3-ethoxypropylamine, isobutylamine, isoamylamine, 3-methoxypropylamine, 2-methoxyethylamine, 2-methylbutylamine, neopentylamine, propylamine, methylamine, ethylamine, butylamine, hexylamine, heptylamine, n-octylamine, 1-aminodecane, nonylamine, 1-aminoundecane, dodecylamine, 1-aminopentadecane, 1-aminotridecane, hexadecylamine, tetradecylamine, etc.

[0066] The polymer may be any polymer having a structural unit containing a basic group and is not particularly limited. However, from the viewpoint of controlling the particle size of the organic-inorganic composite particles, it is preferably a polymer Z having a structural unit containing a basic group represented by the following general formula (Z1-1) or (Z1-2).

[0067]

Chemical formula

[0068] Examples of the compound that provides the first structural unit represented by the formula (Z1-1) include 2-vinylpyridine, 4-vinylpyridine, 4-aminostyrene, 4-dimethylaminostyrene, 1-vinylimidazole, dimethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, dimethylaminobutyl (meth)acrylate, diethylaminoethyl (meth)acrylate, diethylaminopropyl (meth)acrylate, dimethylaminopropylacrylamide, diethylaminopropylacrylamide, allylamine, and the like.

[0069] Examples of the compound that provides the first structural unit represented by the formula (Z1-2) include ethyleneimine, propyleneimine, and the like.

[0070] The polymer Z may have a second structural unit as a lyophilic group. From the viewpoint of controlling the particle size of the organic-inorganic composite particles, it is more preferable to have a structural unit represented by the following formulas (Z2-1) and (Z2-2) as the second structural unit.

[0071]

Chemical formula

[0072]

Chemical formula

[0073] The polyester skeleton in the general formula (Z3) is obtained by self-condensation of hydroxycarboxylic acid, lactone, or mixed condensation of hydroxycarboxylic acid and lactone. Examples of the hydroxycarboxylic acid include 12-hydroxystearic acid, and examples of the lactone include ε-caprolactone, β-propiolactone, γ-butyrolactone, δ-valerolactone, etc. However, it preferably has at least one structural unit derived from 12-hydroxystearic acid, valerolactone, or caprolactone.

[0074] Examples of the compound that provides the second structural unit represented by the formula (Z2-1) include alkyl (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, isopropyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) acrylate, icosanyl (meth) acrylate; aromatic (meth) acrylates such as benzyl (meth) acrylate, phenylethyl (meth) acrylate, (meth) acrylates having an alicyclic structure such as cyclohexyl (meth) acrylate, isobornyl (meth) acrylate; alkyl group-terminated polyalkylene glycol (meth) acrylates such as methoxypolyethylene glycol (meth) acrylate, methoxypolypropylene glycol (meth) acrylate, octoxypolyethylene glycol (meth) acrylate, octoxypolypropylene glycol (meth) acrylate, lauroxypolypropylene glycol (meth) acrylate, lauroxypolypropylene glycol (meth) acrylate, stearoxypolyethylene glycol, stearoxypolypropylene glycol (meth) acrylate, allyloxypolyethylene glycol (meth) acrylate, allyloxypolypropylene glycol (meth) acrylate, nonylphenoxypolyethylene glycol (meth) acrylate, nonylphenoxypolypropylene glycol (meth) acrylate; (meth) acrylate compounds such as glycidyl (meth) acrylate, dicyclopentenyl (meth) acrylate, tricyclodecanyl (meth) acrylate; styrene derivatives monomers such as styrene, α-methylstyrene, 4-tert-butylstyrene, 2,5-dimethylstyrene, p-isobutylstyrene, condensates of allylamine and polyester, and the like.

[0075] Examples of the compound that provides the second structural unit represented by the formula (Z2-2) include condensates of ethyleneimine and polyester, condensates of propyleneimine and polyester, and the like.

[0076] In the polymer Z, the structural units represented by the formula (Z1) and the formula (Z2) can each be used alone, or two or more of each can be used in combination. Further, the polymer Z may be a block copolymer having the first structural unit represented by the formula (Z1) as the first polymer block and the second structural unit represented by the formula (Z2) as the second polymer block, or may be a random polymer having the first structural unit represented by the formula (Z1) and the second structural unit represented by the formula (Z2) randomly, or may be a graft polymer having the first structural unit represented by the formula (Z1) and the second structural unit represented by the formula (Z2). From the viewpoint of the adsorptivity to the surface of the nanocrystal containing the hydrolytic condensate of the silane ligand T, the polymer Z is preferably a block copolymer or a graft polymer.

[0077] In the polymer Z, at least one of the structural units represented by the formula (Z1-1) and the formula (Z1-2) can be used, and at least one of the structural units represented by the formula (Z2-1) and the formula (Z2-2) can be used. Further, the polymer B may be a block copolymer having the first structural unit represented by the formula (Z1-1) as the first polymer block and the second structural unit represented by the formula (Z2-1) as the second polymer block, or may be a random polymer having the first structural unit represented by the formula (Z1-2) and the second structural unit represented by the formula (Z2-2) randomly, or may be a graft polymer having the first structural unit represented by the formula (Z1-2) and the second structural unit represented by the formula (Z2-2). From the viewpoint of the uniformity of the size of the luminescent particles, the polymer Z is preferably a block copolymer or a graft polymer.

[0078] The content of the first structural unit in Polymer Z is preferably, for example, 3 mol% or more, 4 mol% or more, or 5 mol% or more, and preferably 50 mol% or less, 30 mol% or less, or 20 mol% or less, based on all the structural units constituting Polymer Z.

[0079] The content of the second structural unit in Polymer Z is preferably, for example, 70 mol% or more, 75 mol% or more, or 80 mol% or more, and preferably 97 mol% or less, 96 mol% or less, or 95 mol% or less, based on all the structural units constituting Polymer Z.

[0080] In addition to the first structural unit and the second structural unit, Polymer Z may contain other structural units. In that case, the total content of the first structural unit and the second structural unit in Polymer Z is preferably, for example, 70 mol% or more, 80 mol% or more, or 90 mol% or more, based on all the structural units constituting Polymer Z.

[0081] For example, in addition to the first structural unit and the second structural unit, Polymer Z may have a structural unit having an acidic group.

[0082] Examples of the acidic group include a carboxyl group (-COOH), a sulfo group (-SO3H), a sulfuric acid group (-OSO3H), a phosphonic acid group (-PO(OH)3), a phosphoric acid group (-OPO(OH)3), a phosphinic acid group (-PO(OH)-), and a mercapto group (-SH). Examples of the nonionic functional group include a hydroxy group, an ether group, a thioether group, a sulfinyl group (-SO-), a sulfonyl group (-SO2-), a carbonyl group, a formyl group, an ester group, a carbonate ester group, an amide group, a carbamoyl group, a ureido group, a thioamide group, a thioureido group, a sulfamoyl group, a cyano group, an alkenyl group, an alkynyl group, a phosphine oxide group, and a phosphine sulfide group.

[0083] Examples of the compound that provides a structural unit having an acidic group include (meth)acrylates having a carboxy group, (meth)acrylates having a phosphoric acid group, and (meth)acrylates having a sulfone group. Examples of the (meth)acrylate having a carboxy group include monomers obtained by reacting (meth)acrylates having a hydroxy group, such as carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl maleate, and 2-(meth)acryloyloxyethyl phthalate, with acid anhydrides such as maleic anhydride, succinic anhydride, and phthalic anhydride, and (meth)acrylic acid. Examples of the (meth)acrylate having a sulfonic acid group include sulfonic acid ethyl (meth)acrylate. Examples of the (meth)acrylate having a phosphoric acid group include 2-(phosphonooxy)ethyl (meth)acrylate.

[0084] The weight average molecular weight (Mw) in Polymer Z is a value measured by gel permeation chromatography (GPC) and is expressed as a standard polystyrene equivalent value. From the viewpoint of the dispersibility of the luminescent particles, it is preferably in the range of 3,000 or more and 200,000 or less, more preferably in the range of 4,000 or more and 100,000 or less, and even more preferably in the range of 5,000 or more and 80,000 or less.

[0085] 1-3. Method for producing luminescent particles One embodiment of the present invention is a method for producing luminescent particles having a surface layer containing a hydrolysis condensate of a silane compound of T unit and Q unit and an organic component on the surface of semiconductor nanocrystal particles composed of metal halide. The production method according to one embodiment includes obtaining semiconductor nanocrystal particles and precursor particles having a layer containing a hydrolysis condensate of a silane ligand T on the surface thereof from a solution containing a raw material compound of the semiconductor nanocrystal particles, a silane ligand T having a bonding group capable of bonding to the surface of the semiconductor nanocrystal particles and a hydrolyzable silyl group, and a solvent in step S1; mixing the precursor particles, a polymer having a first structural unit having a basic group and a second structural unit having no basic group and being lyophilic with a solvent to obtain a mixture in step S2; and adding a silane compound having a Q unit and a halogenated alkoxysilane compound to the mixture to form a polysiloxane bond, thereby obtaining luminescent particles having a layer containing a polymer, a hydrolysis condensate of the silane compound of Q unit and a hydrolysis condensate of the halogenated alkoxysilane compound on the surface of the precursor particles in step S3.

[0086] <<Step S1>> In step S1, for example, a first solution containing a raw material compound of semiconductor nanocrystal particles and a second solution containing a silane ligand T are mixed to generate semiconductor nanocrystal particles composed of metal halide and coordinate the silane ligand T on the surface of the semiconductor nanocrystal particles. Then, the hydrolyzable silyl groups in the coordinated silane ligand T are condensed to form siloxane bonds. Thus, precursor particles having a layer containing a hydrolysis condensate of the silane ligand T on the surface of the semiconductor nanocrystal are obtained.

[0087] In step S1, when mixing the first solution and the second solution, heating may or may not be performed. When heating during the mixing of the first solution and the second solution, for example, the first solution may contain a part of the raw material compound of the semiconductor nanocrystal particles, and the second solution may contain the remainder of the raw material compound of the semiconductor nanocrystal particles in addition to the silane ligand T. Then, these solutions are mixed in an inert gas atmosphere and reacted, for example, under temperature conditions of 130 to 260°C. Then, it is cooled to -20 to 30°C and stirred to generate semiconductor nanocrystal particles and bond the silane ligand T to the surface of the semiconductor nanocrystal particles, and then a siloxane bond can be formed by condensing the hydrolyzable silyl groups in the silane ligand T.

[0088] Specifically, for example, a solution containing cesium carbonate, which is a part of the raw material compound, a compound acting as a ligand of the semiconductor nanocrystal particles, and an organic solvent is prepared. As the compound acting as a ligand of the semiconductor nanocrystal particles, oleic acid, oleylamine, etc. can be used. As the organic solvent, 1-octadecene, dioctyl ether, diphenyl ether, etc. can be used. At this time, it is preferable to adjust the addition amounts of each so that the raw material compound such as cesium carbonate is 0.2 to 2 g and the compound acting as a ligand such as oleic acid is 0.1 to 10 mL with respect to 40 mL of the organic solvent. After the obtained solution is dried under reduced pressure at 90 to 150°C for 10 to 180 minutes, it is heated to 100 to 200°C in an inert gas atmosphere such as argon or nitrogen to obtain a cesium-oleic acid solution.

[0089] Prepare a solution containing lead(II) bromide, which is the remainder of the raw material compound, a compound that acts as a ligand for the semiconductor nanocrystal particles, and an organic solvent. The compound that acts as a ligand for the semiconductor nanocrystal particles and the organic solvent are the same as those used in the preparation of the solution containing cesium carbonate. To 5 mL of the organic solvent, add 20 to 100 mg of a raw material compound such as lead(II) bromide, and add a compound that acts as a ligand such as oleic acid so that the amount is 0.1 to 10 mL. After drying the obtained solution under reduced pressure at 90 to 150 °C for 10 to 180 minutes, add 0.1 to 2 mL of 3-aminopropyltriethoxysilane, which is a silane ligand T, in an inert gas atmosphere such as argon or nitrogen.

[0090] Then, while heating the solution containing lead(II) bromide and 3-aminopropyltriethoxysilane to 130 to 260 °C, add the above-mentioned cesium-oleic acid solution and react by heating and stirring for 1 to 10 seconds. After that, cool the obtained reaction solution in an ice bath. At this time, it is preferable to add 0.1 to 1 mL of the cesium-oleic acid solution to 5 mL of the solution containing lead(II) bromide, oleic acid, and 3-aminopropyltriethoxysilane. During stirring at -20 to 30 °C, semiconductor nanocrystal particles are generated, and 3-aminopropyltriethoxysilane and oleic acid are coordinated on the surface of the semiconductor nanocrystal particles.

[0091] Thereafter, add 0.1 to 60 mL of methyl acetate to the obtained reaction solution to obtain a suspension. After centrifuging the obtained suspension and removing the supernatant, a solid containing precursor particles is obtained.

[0092] When not heating during the mixing of the first solution and the second solution, first, the first solution containing the raw material compound of the semiconductor nanocrystal particles and the second solution containing the silane ligand T are mixed in the air. Next, the obtained mixture is used to generate semiconductor nanocrystal particles by adding a large amount of an organic solvent, which is a poor solvent for the semiconductor nanocrystal particles. The amount of the organic solvent used is preferably 10 to 1000 times the amount of the semiconductor nanocrystal particles on a mass basis. Further, on the surface of the generated semiconductor nanocrystal particles, siloxane bonds are formed by the hydrolyzable silyl groups of the silane ligand T.

[0093] Specifically, as the first solution containing the raw material compound of the semiconductor nanocrystal particles, for example, a solution containing lead(II) bromide, which is a part of the raw material compound, and methylamine hydrobromide and an organic solvent is prepared. The organic solvent may be a good solvent for the nanocrystals, but dimethyl sulfoxide, N,N-dimethylformamide, N-methylformamide, and mixed solvents thereof are preferred from the viewpoint of compatibility. At this time, it is preferable to adjust the addition amounts so that for 10 mL of the organic solvent, 50 to 200 mg of lead(II) bromide and 10 to 100 mg of methylamine hydrobromide are obtained.

[0094] On the other hand, as the second solution containing the silane ligand T, for example, a solution containing 3-aminopropyltriethoxysilane, a ligand acting as the semiconductor nanocrystal particles, and a poor solvent is prepared. As the ligand acting as the semiconductor nanocrystal particles, for example, oleic acid, oleylamine, etc. can be used. As the poor solvent, isopropyl alcohol, toluene, hexane, cyclohexane, methyl acetate, ethyl acetate, butyl acetate, acetone, acetonitrile, etc. can be used. At this time, it is preferable to adjust the addition amounts so that for 5 mL of the poor solvent, 0.01 to 0.5 mL of the silane ligand T such as 3-aminopropyltriethoxysilane and 0.01 to 0.5 mL of the ligand such as oleic acid are obtained.

[0095] Then, 5 mL of the solution containing 3-aminopropyltriethoxysilane described above is added to 0.1 to 5 mL of the solution containing lead(II) bromide and methylamine hydrobromide described above at 0 to 60 °C under the atmosphere to obtain a mixture. Immediately thereafter, the obtained mixture is added to a large amount of poor solvent, and after centrifugation, the supernatant is removed to obtain a solid containing precursor particles. When the mixture is added to a large amount of poor solvent, semiconductor nanocrystal particles precipitate, and 3-aminopropyltriethoxysilane and oleic acid coordinate on the surface of the semiconductor nanocrystal particles. Then, the alkoxysilyl groups of 3-aminopropyltriethoxysilane are condensed, and a siloxane bond is formed between the hydrolyzable silyl groups of the silane ligand T on the surface of the semiconductor nanocrystal particles.

[0096] The semiconductor nanocrystal particles composed of metal halides produced in step S1 are nanosized crystals (nanocrystal particles) that absorb excitation light and emit fluorescence or phosphorescence. The semiconductor nanocrystal particles are, for example, particles having a maximum particle diameter of 100 nm or less measured by a transmission electron microscope or a scanning electron microscope. The semiconductor nanocrystal particles can be excited by light energy or electrical energy of a predetermined wavelength, for example, and emit fluorescence or phosphorescence.

[0097] It is preferable that a ligand is coordinated on the surface of the semiconductor nanoparticles in order to enhance the stability. By adding a ligand to the first solution and / or the second solution containing the raw material compound of the semiconductor nanocrystal particles, semiconductor nanoparticles with a ligand coordinated on the surface can be produced.

[0098] The silane ligand T is a compound having a bonding group and a hydrolyzable silyl group that can bind to the surface of the semiconductor nanocrystal particles, and one or more kinds can be used in step S1.

[0099] <<Step S2>> In step S2, for example, a polymer solution in which a polymer Z having a first structural unit having a basic group and a second structural unit having no basic group and being lyophilic is dissolved in a solvent such as toluene is added to the solid containing the precursor particles, and further, a halogenated alkoxysilane compound having a T unit is added. As a result, a state is formed in which the first structural unit having a basic group in the polymer Z gathers toward the side of the precursor particles on the surface of the precursor particles. A part of the polymer Z forms a salt with the halogen of the halogenated alkoxysilane compound (hereinafter also referred to as "polymer Z'"), and the polymer Z' serves as a halogen source for nanocrystals in the surface layer formed on the surface of the luminescent particles.

[0100] Specifically, for example, first, the polymer Z is added to a solvent so as to have a concentration of 0.1 to 100 mg / mL and dissolved at a temperature of 20 to 80°C. Subsequently, for 1 part by mass of the solid containing the precursor particles, for example, 10 to 1000 parts by mass of the polymer solution is added and stirred for 1 to 60 minutes. Further, for 1 part by mass of the solid, for example, 10 to 1000 parts by mass of the halogenated alkoxysilane compound is added and stirred for 6 to 24 hours. Then, after centrifuging at 3000 to 10000 revolutions per minute for 1 to 30 minutes, the supernatant (for example, 70 to 100 volume% of the supernatant with respect to the total amount of the solution) is recovered, whereby a dispersion liquid S2 containing the precursor particles, the polymer, and the halogenated alkoxysilane compound of the T unit can be obtained.

[0101] The polymer Z used in step S2 is an amphiphilic compound, and is a polymer having a first structural unit having a basic group and a second structural unit having excellent affinity for the dispersion medium and being lyophilic and having no basic group. The dispersion medium referred to here is a dispersion medium capable of dispersing the luminescent particles. The dispersion medium may be the solvent used in step S2, or may be another solvent or a resin such as a photopolymerizable compound.

[0102] <<Step S3>> In step S3, for example, the dispersion liquid S2 obtained in step S2 and a solution containing a silane compound Q are mixed. The hydrolyzable silyl groups of the halogenated alkoxysilane compound of the T unit in the dispersion liquid S2 and the hydrolyzable silyl groups of the silane compound Q condense to form a siloxane bond, whereby a layer containing the polymer Z, the hydrolyzate of the halogenated alkoxysilane compound of the T unit, and the silane compound Q is formed on the surface of the precursor particles. As a result, luminescent particles having a surface layer containing Si are formed on the surface of the semiconductor nanocrystal particles. The surface layer contains polysiloxane derived from the silane compound T, the polymer Z, polysiloxane derived from the halogenated alkoxysilane compound of the T unit, and polysiloxane derived from the silane compound Q. Thereafter, the obtained reaction solution is centrifuged and the supernatant is recovered, whereby a dispersion liquid of the luminescent particles dispersed in the solvent can be obtained.

[0103] Specifically, for example, a solution containing the silane compound Q is added to the polymer solution so that the silane compound Q is, for example, 0.1 to 50 parts by mass with respect to 1 part by mass of the precursor particles in the polymer solution obtained in step S2, and the mixture is stirred for, for example, 5 to 300 minutes.

[0104] After mixing the dispersion liquid of the luminescent particles and the solution containing the silane compound Q, water (for example, ion-exchanged water) may be further added from the viewpoint of hydrolysis control. The addition amount of water may be, for example, 1 to 100 parts by mass with respect to 100 parts by mass of the silane compound Q. After adding water, the mixture is stirred for, for example, 5 to 300 minutes.

[0105] Subsequently, the obtained reaction solution is centrifuged under conditions of, for example, 3000 to 15000 revolutions per minute for 1 to 30 minutes, and then the supernatant (for example, 70 to 100 volume% of the total amount of the reaction solution) is recovered, whereby a dispersion of the luminescent particles in which the luminescent particles are dispersed in the solvent can be obtained.

[0106] In the luminescent particle dispersion obtained by the production method of the present embodiment, the surface layer containing Si included in the luminescent particles dispersed in the solvent includes polysiloxane resulting from silane compound T, polymer Z, polysiloxane resulting from the halogenated alkoxysilane compound of the T unit, and polysiloxane resulting from silane compound Q. Since the polysiloxane resulting from silane compound T is bonded (coordinated) to the semiconductor nanocrystal particles by the bonding group, it is considered to be unevenly distributed on the semiconductor nanoparticle side. On the surface side of the polysiloxane resulting from silane compound T, polymer Z aggregates so that the basic group in the first structural unit is positioned on the semiconductor nanocrystal particle side. In polymer Z, the basic group in the first structural unit may be bonded (coordinated) to the semiconductor nanocrystal particles or may be bonded (coordinated) to the polysiloxane resulting from silane compound T. The polysiloxane resulting from the halogenated alkoxysilane compound of the T unit and the polysiloxane resulting from silane compound Q are considered to be unevenly distributed more outward than the polysiloxane resulting from silane compound T in the surface layer. The polysiloxane resulting from the halogenated alkoxysilane compound of the T unit and the polysiloxane resulting from silane compound Q may be coordinated (bonded) to the basic group in the first structural unit of polymer Z. The polysiloxane resulting from the halogenated alkoxysilane compound of the T unit and the polysiloxane resulting from silane compound Q are considered to be formed on the surface of the particles using the first structural unit having the basic group of polymer Z as a template. According to the above, since the surface of the luminescent particles is firmly coated with a layer having Si, the luminescent particle dispersion can ensure excellent stability against polar solvents such as oxygen, heat, and water. Furthermore, since the basic group in the first structural unit of polymer Z is positioned on the semiconductor nanocrystal particle side, the second structural unit having lyophilicity is arranged outside the surface of the luminescent particles, so that high dispersibility of the luminescent particles in the luminescent particle dispersion with respect to the dispersion medium in the luminescent particle dispersion can be imparted. As described above, according to the production method of the present embodiment, a luminescent particle dispersion excellent in dispersibility and stability can be obtained.

[0107] The thickness of the surface layer is preferably, for example, 1 nm or more, 2 nm or more, or 3 nm or more, and preferably 200 nm or less, 100 nm or less, or 50 nm or less. The luminescent particles having such a surface layer thickness can achieve excellent stability and excellent dispersibility in the dispersion medium.

[0108] The average particle diameter (volume average diameter) of the luminescent particles is preferably, for example, 10 nm or more, 15 nm or more, or 20 nm or more, and preferably 400 nm or less, 300 nm or less, or 200 nm or less. The average particle diameter of the luminescent particles means the volume average diameter measured by the dynamic light scattering method.

[0109] 2. Ink composition The luminescent particles of the present invention are preferably used as an ink composition dispersed in a dispersion medium. It is preferable to use a solvent or a photopolymerizable compound as the dispersion medium. The ink composition preferably contains at least a photopolymerizable compound as the dispersion medium and further contains a photoinitiator. Such an ink composition is particularly suitable as an ultraviolet curable coating composition for a light conversion film or an ink composition for ultraviolet curable inkjet. At this time, it may or may not contain a solvent. Hereinafter, the luminescent particles, the photopolymerizable compound, and the ink composition containing the photopolymerizable compound will be described.

[0110] The details of the luminescent particles are as described above. The content of the luminescent particles in the ink composition is preferably 0.05% by mass or more, 0.1% by mass or more, 0.5% by mass or more, or 1% by mass or more, and preferably 20% by mass or less, 15% by mass or less, 10% by mass or less, or 5% by mass or less. By setting the content of the luminescent powder within the above range, it becomes difficult for the luminescent particles to aggregate, and the storage stability in the ink composition and the internal quantum efficiency of the obtained luminescent layer (light conversion layer) can also be improved.

[0111] The photopolymerizable compound contained in the ink composition of the present invention functions as a binder in the cured product and is a compound that polymerizes upon irradiation with light (active energy rays). Examples of the photopolymerizable compound include radical polymerizable compounds, cationic polymerizable compounds, anionic polymerizable compounds, etc., and it may be a monomer or an oligomer. Among them, from the viewpoint of good curability, radical polymerizable compounds are preferred.

[0112] Examples of the radical polymerizable compound include compounds having an ethylenically unsaturated group as a polymerizable functional group. In the present specification, the ethylenically unsaturated group means a group having an ethylenically unsaturated bond (polymerizable carbon-carbon double bond). Examples of the ethylenically unsaturated group include a vinyl group, a vinylene group, a vinylidene group, a (meth)acryloyl group, etc. The number of ethylenically unsaturated bonds (for example, the number of ethylenically unsaturated groups) possessed by the compound having an ethylenically unsaturated group may be, for example, 1 to 6. As the compound having an ethylenically unsaturated group, from the viewpoint of further improving the external quantum efficiency of the cured product obtained from the ink composition, compounds having a (meth)acryloyl group are preferred, monofunctional or polyfunctional (meth)acrylates are more preferred, and monofunctional or bifunctional (meth)acrylates are even more preferred. In the present specification, the term “(meth)acryloyl group” is a general term for an acryloyl group, a methacryloyl group, and both of them. “(Meth)acrylate” is a general term for acrylate, methacrylate, and both of them. In addition, monofunctional (meth)acrylate means a (meth)acrylate having one (meth)acryloyl group, and polyfunctional (meth)acrylate means a (meth)acrylate having two or more (meth)acryloyl groups.

[0113] Examples of monofunctional (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, amyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, dodecyl (meth)acrylate, hexadecyl (meth)acrylate, octadecyl (meth)acrylate, cyclohexyl (meth)acrylate, methoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, phenoxyethyl (meth)acrylate, nonylphenoxyethyl (meth)acrylate, glycidyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, benzyl (meth)acrylate, phenylbenzyl (meth)acrylate, succinic acid mono(2-acryloyloxyethyl), N-[2-(acryloyloxy)ethyl]phthalimide, N-[2-(acryloyloxy)ethyl]tetrahydrophthalimide, and the like.

[0114] Polyfunctional (meth)acrylates include difunctional (meth)acrylates, trifunctional (meth)acrylates, tetrafunctional (meth)acrylates, pentafunctional (meth)acrylates, hexafunctional (meth)acrylates, and the like. For example, di(meth)acrylates in which two hydroxyl groups of a diol compound are substituted with (meth)acryloyloxy groups, di(meth)acrylates or tri(meth)acrylates in which two or three hydroxyl groups of a triol compound are substituted with (meth)acryloyloxy groups, and the like can be mentioned.

[0115] Examples of the bifunctional (meth)acrylate include 1,3-butylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,5-pentanediol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,8-octanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol hydroxy pivalate diester diacrylate, di(meth)acrylate in which two hydroxyl groups of tris(2-hydroxyethyl) isocyanurate are substituted by (meth)acryloyloxy groups, di(meth)acrylate in which two hydroxyl groups of a diol obtained by adding 4 moles or more of ethylene oxide or propylene oxide to 1 mole of neopentyl glycol are substituted by (meth)acryloyloxy groups, di(meth)acrylate in which two hydroxyl groups of a diol obtained by adding 2 moles of ethylene oxide or propylene oxide to 1 mole of bisphenol A are substituted by (meth)acryloyloxy groups, di(meth)acrylate in which two hydroxyl groups of a triol obtained by adding 3 moles or more of ethylene oxide or propylene oxide to 1 mole of trimethylolpropane are substituted by (meth)acryloyloxy groups, di(meth)acrylate in which two hydroxyl groups of a diol obtained by adding 4 moles or more of ethylene oxide or propylene oxide to 1 mole of bisphenol A are substituted by (meth)acryloyloxy groups, di(meth)acrylate obtained by adding (meth)acrylic acid to the reaction product of 1 mole of propylene glycol and 2 moles of epichlorohydrin, and the like.

[0116] Examples of the trifunctional (meth)acrylate include trimethylolpropane tri(meth)acrylate, glycerin triacrylate, pentaerythritol tri(meth)acrylate, and tri(meth)acrylate in which three hydroxyl groups of a triol obtained by adding 3 moles or more of ethylene oxide or propylene oxide to 1 mole of trimethylolpropane are substituted with (meth)acryloyloxy groups. Examples of the tetrafunctional (meth)acrylate include pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, and the like. Examples of the pentafunctional (meth)acrylate include dipentaerythritol penta(meth)acrylate, and the like. Examples of the hexafunctional (meth)acrylate include dipentaerythritol hexa(meth)acrylate, and the like.

[0117] The polyfunctional (meth)acrylate may be at least one compound selected from the group consisting of poly(meth)acrylates in which a plurality of hydroxyl groups of dipentaerythritol such as dipentaerythritol hexa(meth)acrylate are substituted with (meth)acryloyloxy groups, aromatic urethane oligomers having two or more ethylenic double bonds in one molecule, aliphatic urethane oligomers, epoxy acrylate oligomers, polyester acrylate oligomers, and other special oligomers.

[0118] The (meth)acrylate compound may be a phosphoric acid group-containing ethylene oxide-modified phosphoric acid (meth)acrylate, ethylene oxide-modified alkyl phosphoric acid (meth)acrylate, or the like.

[0119] The content of the photopolymerizable compound in the ink composition of the present invention is preferably 40% by mass or more and 99% by mass or less, more preferably 60% by mass or more and 98% by mass or less, and even more preferably 70% by mass or more and 97% by mass or less, based on the total mass of the ink composition.

[0120] From the viewpoint of reducing the tack on the surface of the cured product of the composition, it is preferable to use a radically polymerizable compound having a cyclic structure as the photopolymerizable compound. The cyclic structure may be an aromatic ring structure or a non-aromatic ring structure. The number of cyclic structures (the total number of aromatic rings and non-aromatic rings) is 1 or 2 or more, but preferably 3 or less. The number of carbon atoms constituting the cyclic structure is, for example, 4 or more, preferably 5 or more or 6 or more. The number of carbon atoms is, for example, 20 or less, preferably 18 or less.

[0121] The aromatic ring structure preferably has an aromatic ring having 6 to 18 carbon atoms. Examples of the aromatic ring having 6 to 18 carbon atoms include a benzene ring, a naphthalene ring, a phenanthrene ring, and an anthracene ring. The aromatic ring structure may have an aromatic heterocyclic ring. Examples of the aromatic heterocyclic ring include a furan ring, a pyrrole ring, a pyran ring, and a pyridine ring. The number of aromatic rings may be 1 or 2 or more, but is preferably 3 or less. The organic group may have a structure in which two or more aromatic rings are bonded by a single bond (for example, a biphenyl structure).

[0122] The non-aromatic ring structure preferably has, for example, an alicyclic ring having 5 to 20 carbon atoms. Examples of the alicyclic ring having 5 to 20 carbon atoms include cycloalkane rings such as a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, and a cyclooctane ring, and cycloalkene rings such as a cyclopentene ring, a cyclohexene ring, a cycloheptene ring, and a cyclooctene ring. The alicyclic ring may be a condensed ring such as a bicycloundecane ring, a decahydronaphthalene ring, a norbornene ring, a norbornadiene ring, or an isobornyl ring. The non-aromatic ring structure may have a non-aromatic heterocyclic ring. Examples of the non-aromatic heterocyclic ring include a tetrahydrofuran ring, a pyrrolidine ring, a tetrahydropyran ring, and a piperidine ring.

[0123] The radically polymerizable compound having a cyclic structure is preferably a monofunctional or polyfunctional (meth)acrylate having a cyclic structure. Examples of the monofunctional (meth)acrylate having a cyclic structure include phenoxyethyl (meth)acrylate, phenoxybenzyl (meth)acrylate, biphenyl (meth)acrylate, isobornyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, dicyclopentenyl oxyethyl (meth)acrylate, and the like. Examples of the polyfunctional (meth)acrylate having a cyclic structure include dimethylol-tricyclodecane diacrylate, EO-modified bisphenol A diacrylate, PO-modified bisphenol A diacrylate, and the like.

[0124] From the viewpoint of exhibiting excellent heat resistance in the light conversion layer formed from the ink composition, the content of the radically polymerizable compound having a cyclic structure is preferably 40 to 95% by mass, more preferably 60 to 90% by mass, and even more preferably 70 to 85% by mass based on the total mass of the photopolymerizable compounds in the ink composition.

[0125] The molecular weight of the photopolymerizable compound is, for example, 50 or more, and may be 100 or more or 150 or more. The molecular weight of the photopolymerizable compound is, for example, 500 or less, and may be 400 or less or 300 or less. When the ink composition of the present invention is applied using an inkjet printing method, from the viewpoint of easily achieving both viscosity and ink volatility resistance after ejection, the molecular weight of the photopolymerizable compound is preferably 50 to 500, and more preferably 100 to 400. When the ink composition of the present invention is applied to a substrate such as a film using a printing method such as a roll coater, a gravure coater, a flexo coater, or a die coater, from the viewpoint of easily achieving both viscosity and leveling property, the molecular weight of the photopolymerizable compound is preferably 100 to 500, and more preferably 150 to 400.

[0126] In the ink composition of the present invention, when a photopolymerizable compound having two or more polymerizable functional groups in one molecule is used as an essential component as the curable component, it is preferable from the viewpoint of improving the durability (strength, heat resistance, etc.) of the obtained cured product. More specifically, from the viewpoints of excellent viscosity stability, ejection property, and coating property when preparing the ink composition, good curability of the ink composition, suppressing a decrease in the smoothness of the coating film surface due to curing shrinkage during the production of a cured product such as a coating film containing a light-emitting powder, in the light conversion layer composed of the ink composition of the present invention, improving the adhesion to a substrate such as plastic or glass, solvent resistance, and abrasion resistance, and obtaining excellent optical properties (for example, external quantum efficiency), it is preferable to use two or more radical polymerizable compounds, preferably in combination with a monofunctional (meth)acrylate and a polyfunctional (meth)acrylate, more preferably in combination with a monofunctional (meth)acrylate, a difunctional (meth)acrylate, and a polyfunctional (meth)acrylate having three or more functional groups, and particularly preferably in combination with a monofunctional acrylate, a difunctional acrylate, and a polyfunctional acrylate having three or more functional groups.

[0127] In the ink composition of the present invention, the content of the monofunctional (meth)acrylate as the photopolymerizable compound is preferably 20% by mass or more and 50% by mass or less, more preferably 25% by mass or more and 45% by mass or less, and even more preferably 30% by mass or more and 40% by mass or less based on the total amount of the photopolymerizable compound from the viewpoints of the dispersion stability of the light-emitting particles in the ink composition and the curability when forming the light conversion layer. The content of the difunctional (meth)acrylate is preferably 20% by mass or more and 70% by mass or less, more preferably 30% by mass or more and 65% by mass or less, and even more preferably 40% by mass or more and 60% by mass or less based on the total amount of the photopolymerizable compound. The content of the polyfunctional (meth)acrylate having three or more functional groups is preferably 5% by mass or more and 25% by mass or less, more preferably 7% by mass or more and 23% by mass or less, and even more preferably 10% by mass or more and 20% by mass or less based on the total amount of the photopolymerizable compound.

[0128] Examples of the photopolymerization initiator contained in the ink composition of the present invention include molecular cleavage type or hydrogen abstraction type photoradical polymerization initiators. Examples of the molecular cleavage type photoradical polymerization initiator include benzoin isobutyl ether, 2,4 - diethylthioxanthone, 2 - isopropylthioxanthone, 2,4,6 - trimethylbenzoyldiphenylphosphine oxide, 2 - benzyl - 2 - dimethylamino - 1 - (4 - morpholinophenyl) - butan - 1 - one, bis(2,6 - dimethoxybenzoyl) - 2,4,4 - trimethylpentylphosphine oxide, (2,4,6 - trimethylbenzoyl)ethoxyphenylphosphine oxide, etc. In addition to these, 1 - hydroxycyclohexyl phenyl ketone, benzoin ethyl ether, benzyl dimethyl ketal, 2 - hydroxy - 2 - methyl - 1 - phenylpropan - 1 - one, 1 - (4 - isopropylphenyl) - 2 - hydroxy - 2 - methylpropan - 1 - one, 2 - methyl - 1 - (4 - methylthiophenyl) - 2 - morpholinopropan - 1 - one, etc. may be used in combination. Examples of the hydrogen abstraction type photoradical polymerization initiator include benzophenone, 4 - phenylbenzophenone, isophthalophenone, 4 - benzoyl - 4'-methyl - diphenyl sulfide, etc. The molecular cleavage type photoradical polymerization initiator and the hydrogen abstraction type photoradical polymerization initiator may be used in combination.

[0129] Further, as the photopolymerization initiator, it is preferable to contain a photopolymerization initiator having photobleaching properties. In this case, the light transmittance of the cured product of the ink composition of the present invention is likely to increase. Examples of the photopolymerization initiator having photobleaching properties preferably contain at least one of an oxime ester - based compound or an acylphosphine oxide - based compound having photobleaching properties. Examples of the oxime ester compounds having photobleaching properties include 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyloxime), ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime), and the like. Examples of the acylphosphine oxide compounds having photobleaching properties include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide, and the like. From the viewpoint of forming a cured product having excellent internal curability and a small initial coloring degree, it is preferable to contain at least one or more acylphosphine oxide compounds. In this case, it is also preferable from the viewpoint of being suitable for curing using an ultraviolet light-emitting diode (UV-LED) having a narrow spectral output in the range of ±15 nm centered on a specific wavelength such as 365 nm, 385 nm, 395 nm, or 405 nm.

[0130] From the viewpoints of solubility in the photopolymerizable compound, curability of the ink composition, and stability over time (maintenance stability of internal quantum efficiency) of the light conversion layer formed from the ink composition, the content of the photopolymerization initiator is preferably 0.1 to 20% by mass, more preferably 0.5 to 15% by mass, still more preferably 1 to 15% by mass, and particularly preferably 3 to 7% by mass with respect to the photopolymerizable compound in the ink composition.

[0131] The ink composition of the present invention may further contain other components such as a polymerization inhibitor, an antioxidant, a dispersant, a surfactant, a light-scattering particle, a chain transfer agent, a sensitizer, and a solvent, as long as the effects of the present invention are not inhibited.

[0132] Examples of the polymerization inhibitor include quinone compounds such as p-methoxyphenol, cresol, tert-butylcatechol, 3,5-di-tert-butyl-4-hydroxytoluene; amine compounds such as p-phenylenediamine, 4-aminodiphenylamine, N,N'-diphenyl-p-phenylenediamine; thioether compounds such as phenothiazine, distearyl thiodipropionate; N-oxyl compounds such as 2,2,6,6-tetramethylpiperidine-1-oxyl, 2,2,6,6-tetramethylpiperidine, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl; and nitroso compounds such as N-nitrosodiphenylamine, N-nitrosophenylnaphthylamine, N-nitrosodinaphthylamine. When the polymerization inhibitor is contained, its amount is preferably in the range of 0.01 to 1% by mass, more preferably 0.02 to 0.5% by mass, based on the total amount of the photopolymerizable compounds contained in the ink composition.

[0133] Examples of the antioxidant include phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, etc., such as pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)]propionate, thiodiethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)]propionate, octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, 2,4,8,10-tetrakis(1,1-dimethylethyl)-6-[(2-ethylhexyl)oxy]-12H-dibenz[d,g][1,3,2]dioxaphosphocin, bis[3-(dodecylthio)propionic acid] 2,2-bis[[3-(dodecylthio)-1-oxopropyl)oxy]methyl]-1,3-propanediyl, etc. From the viewpoint of the thermal stability of the ink composition and the light-converting layer formed from the ink composition, phenolic antioxidants and phosphorus-based antioxidants are preferred, and phenolic antioxidants are more preferred. Also, from the viewpoint of the long-term thermal stability of the light-converting layer formed from the ink composition, it is preferable to use a phenolic antioxidant and a phosphorus-based antioxidant in combination. When containing an antioxidant, the amount thereof is preferably in the range of 0.01 to 2% by mass, more preferably 0.02 to 1% by mass, based on the total amount of the photopolymerizable compounds contained in the ink composition, from the viewpoint of not inhibiting the curability of the ink composition.

[0134] Examples of the dispersant include phosphorus atom-containing compounds such as trioctylphosphine, trioctyphosphine oxide, and hexylphosphonic acid; nitrogen atom-containing compounds such as oleylamine, octylamine, and trioctylamine; sulfur atom-containing compounds such as 1-decanethiol, octanethiol, and dodecanethiol; and polymer dispersants such as acrylic resins, polyester resins, and polyurethane resins. These can be obtained as commercially available products such as the "DISPER (registered trademark) BYK" series manufactured by BYK Chemie, the "TEGO (registered trademark) Dispers" series manufactured by Evonik, the "EFKA (registered trademark)" series manufactured by BASF, the "SOLSPERSE (registered trademark)" series manufactured by Lubrizol Japan, the "AJISPER (registered trademark)" series manufactured by Ajinomoto Fine-Techno, the "DISPARLON (registered trademark)" series manufactured by Kusumoto Chemicals, and "FLOWLEN (registered trademark)" manufactured by Kyoeisha Chemical. When containing a dispersant, the amount thereof is preferably in the range of 0.05 to 10% by mass, more preferably 0.1 to 5% by mass, based on the total amount of the photopolymerizable compounds contained in the ink composition.

[0135] As the surfactant, a compound capable of reducing film thickness unevenness is preferred when forming a thin film containing a light-emitting powder. For example, anionic surfactants such as dialkyl sulfosuccinates, alkylnaphthalene sulfonates, and fatty acid salts; nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, and polyoxyethylene-polyoxypropylene block copolymers; cationic surfactants such as alkylamine salts and quaternary ammonium salts; and silicone-based and fluorine-based surfactants. These can be obtained as commercially available products such as the "Megafac (registered trademark)" series manufactured by DIC Corporation, the "Fujagent (registered trademark)" series manufactured by Neos Corporation, the "BYK (registered trademark)" series manufactured by BYK Corporation, the "TEGO (registered trademark) Rad" series manufactured by Evonik Industries AG, the "DISPARLON (registered trademark) OX" series manufactured by Kusumoto Chemicals, Ltd., "Polyflow No. 7", "Floren AC-300", "Floren AC-303", etc. manufactured by Kyoeisha Chemical Co., Ltd. When containing a surfactant, its addition amount is preferably in the range of 0.005 to 2% by mass, more preferably 0.01 to 0.5% by mass, based on the total amount of the photopolymerizable compounds contained in the ink composition.

[0136] The light-scattering particles are preferably optically-inactive inorganic fine particles. The light-scattering particles can scatter the light from the light source portion irradiated on the light-emitting layer (light conversion layer). Examples of the material constituting the light-scattering particles include simple metals such as tungsten, zirconium, titanium, platinum, bismuth, rhodium, palladium, silver, tin, platinum, gold, etc.; metal oxides such as silica, barium sulfate, barium carbonate, calcium carbonate, talc, titanium oxide, clay, kaolin, barium sulfate, barium carbonate, calcium carbonate, alumina white, titanium oxide, magnesium oxide, barium oxide, aluminum oxide, bismuth oxide, zirconium oxide, zinc oxide, etc.; metal carbonates such as magnesium carbonate, barium carbonate, basic bismuth carbonate, calcium carbonate, etc.; metal hydroxides such as aluminum hydroxide, etc.; composite oxides such as barium zirconate, calcium zirconate, calcium titanate, barium titanate, strontium titanate, etc., and metal salts such as basic bismuth nitrate, etc. Among them, from the viewpoint of excellent leakage light reduction effect, it is preferably contains at least one selected from the group consisting of titanium oxide, alumina, zirconium oxide, zinc oxide, calcium carbonate, barium sulfate and silica, more preferably contains at least one selected from the group consisting of titanium oxide, barium sulfate and calcium carbonate, and particularly preferably is titanium oxide.

[0137] When containing light-scattering particles, the amount thereof is, for example, when the ink composition of the present invention is used as a forming material for a color filter layer, preferably in the range of 1 to 10% by mass, more preferably in the range of 2 to 7.5% by mass, and particularly preferably in the range of 3 to 5% by mass with respect to the whole ink composition from the viewpoint of suppressing the transmission of blue light of the backlight. When the ink composition of the present invention is used as a forming material for a light conversion sheet, preferably in the range of 0.1 to 5% by mass, more preferably in the range of 0.15 to 3% by mass, and still more preferably in the range of 0.2 to 1.5% by mass with respect to the whole ink composition from the viewpoint of extracting blue light of the backlight.

[0138] Examples of the chain transfer agent include unsaturated hydrocarbons such as 1,4-terpinolene, α-terpinene, γ-terpinene, and dipentene; aromatic hydrocarbons such as pentaphenylethane and α-methylstyrene dimer; halogenated hydrocarbons such as chloroform, carbon tetrachloride, carbon tetrabromide, and bromotrichloromethane; thiol compounds such as butanethiol, pentanethiol, octanethiol, dodecanethiol, tetradecanethiol, hexadecanethiol, hexanedithiol, decanedithiol, 1,4-butanediol bisthiopropionate, 1,4-butanediol bisthioglycolate, ethylene glycol bisthioglycolate, ethylene glycol bisthiopropionate, trimethylolpropane tristithioglycolate, trimethylolpropane tristithiopropionate, trimethylolpropane tris(3-mercaptobutyrate), pentaerythritol tetrakisthioglycolate, pentaerythritol tetrakisthiopropionate, pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), tris(2-hydroxyethyl) isocyanurate trimercaptopropionate, 1,4-dimethylmercaptobenzene, 2,4,6-trimercapto-s-triazine, 2-(N,N-dibutylamino)-4,6-dimercapto-s-triazine; sulfide compounds such as dimethylxanthogen disulfide, diethylxanthogen disulfide, diisopropylxanthogen disulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, and tetrabutylthiuram disulfide; and N,N-dimethylaniline, N,N-divinylaniline, acrolein, allyl alcohol, and the like. Among them, trimethylolpropane tris(3-mercaptobutyrate), pentaerythritol tetrakis(3-mercaptopropionate), and pentaerythritol tetrakis(3-mercaptobutyrate) are preferred. When the chain transfer agent is contained, its amount is preferably in the range of 0.1 to 30% by mass, more preferably 1 to 25% by mass, and still more preferably 5 to 20% by mass, based on the total amount of the photopolymerizable compounds contained in the ink composition.

[0139] Examples of the solvent include cyclohexane, hexane, heptane, chloroform, toluene, octane, chlorobenzene, tetralin, diphenyl ether, propylene glycol monomethyl ether acetate, butyl carbitol acetate, or a mixture thereof. From the viewpoint of easy removal of the solvent from the ink composition when forming the pixel portion, that is, before curing the ink composition, the boiling point of the solvent is preferably 300 ° C or lower, more preferably 200 ° C or lower, and even more preferably 150 ° C or lower. When the ink composition contains a solvent, the amount thereof is preferably 5% by mass or less based on the whole ink composition. From the viewpoint of eliminating the operation of removing the solvent, it is more preferable that the ink composition does not contain a solvent.

[0140] The method for preparing the ink composition of the present invention is not particularly limited, and it can be prepared by blending the above-described respective components. For example, the light-emitting powder is isolated from the light-emitting powder in the state of a dispersion liquid, and dispersed in the photopolymerizable compound using a ball mill, a sand mill, a bead mill, a three-roll mill, a paint conditioner, an attritor, ultrasonic waves, or the like. Next, it can be prepared by adding a photopolymerization initiator and, if necessary, further other components and stirring and mixing them. When containing light-scattering particles, a mill base in which the light-scattering particles and the polymer dispersant are mixed and dispersed in the photopolymerizable compound by a bead mill is separately prepared, and it can be prepared by mixing the photopolymerizable compound, the photopolymerization initiator, and the light-emitting powder together.

[0141] 3. Light conversion layer The ink composition of the present invention can be applied onto a substrate to form a film, and this film can be cured to obtain a cured product. The light conversion layer made of the cured product of the ink composition of the present invention is suitable for use in a color filter and a wavelength conversion film. As methods for applying the ink composition of the present invention onto a substrate, spin coating, die coating, extrusion coating, roll coating, wire bar coating, gravure coating, spray coating, dipping, inkjet method, printing method, etc. can be mentioned. When applying, if necessary, hydrocarbons, halogenated hydrocarbons, ethers, alcohols, ketones, esters, aprotic polar compounds, etc. may be added to the ink composition as solvents. When a solvent is added, after applying the ink composition onto the substrate, natural drying, drying under heating or under reduced pressure is performed.

[0142] When applying the ink composition of the present invention onto a substrate, the shape of the substrate may have a curved surface as a constituent part in addition to a flat plate. As the material constituting the substrate, either an organic material or an inorganic material can be used. Examples of organic materials include polyethylene terephthalate, polycarbonate, polyimide, polyamide, polymethyl methacrylate, polystyrene, polyvinyl chloride, polytetrafluoroethylene, polychlorotrifluoroethylene, polyarylate, polysulfone, triacetyl cellulose, cellulose, polyether ether ketone, etc., and examples of inorganic materials include silicon, glass, calcite, etc.

[0143] The curing of the ink composition of the present invention is preferably carried out by irradiating active energy rays such as ultraviolet rays or electron beams. Details will be described later in the explanation of the preparation of the light conversion layer.

[0144] The wavelength conversion film using the ink composition of the present invention as a forming material may be heat-treated in order to reduce initial characteristic changes and achieve stable characteristic expression. Such heat treatment is preferably carried out in a temperature range of 50 to 250°C and a treatment time of 30 seconds to 12 hours.

[0145] The wavelength conversion film obtained by such a method may be peeled off from the substrate and used alone, or may be used without peeling. Also, the obtained wavelength conversion films may be laminated or bonded to other substrates for use. When using a wavelength conversion film formed of the ink composition of the present invention as a forming material in a laminate structure, such a laminate structure may have any layer such as a substrate, a barrier layer, a light scattering layer, etc. The material constituting the substrate is as described above. Examples of the barrier layer include polyethylene terephthalate, glass, etc. Examples of the light scattering layer include a layer containing the light scattering particles and a light scattering film. As a configuration example of the laminate structure, for example, a structure in which a light conversion layer formed of the ink composition of the present invention is sandwiched between two substrates can be mentioned. In that case, in order to protect the light conversion layer from moisture and oxygen, the outer peripheral portion between the substrates may be sealed with a sealing material. FIG. 1 is a cross-sectional view schematically showing the configuration of the laminate structure of the present embodiment. In the laminate structure 40, a wavelength conversion film 44 of the present embodiment is sandwiched between a first substrate 41 and a second substrate 42. The wavelength conversion film 44 is formed using the ink composition of the present invention containing light scattering particles 441 and luminescent powder 442, and the light scattering particles 441 and the luminescent powder 442 are uniformly dispersed in the wavelength conversion film. The wavelength conversion film 44 is sealed by a sealing layer 43 formed of a sealing material.

[0146] The laminate structure formed of the ink composition of the present invention as a forming material is suitable for, for example, prism sheets, light guide plates, laminate structures containing the luminescent powder of the present invention, and light emitting device applications having a light source. Examples of the light source include light emitting diodes, lasers, and electroluminescent devices. Further, the laminate structure formed of the ink composition of the present invention as a forming material is preferably used as a wavelength conversion member for a display. As a configuration example when used as a wavelength conversion member, for example, a structure in which a laminate structure in which a wavelength conversion film formed of the ink composition of the present invention is sealed between two barrier layers is installed on a light guide plate can be mentioned. In this case, by passing the blue light from the light emitting diode installed on the side surface of the light guide plate through the laminate structure, it can be converted into green light or red light, and the blue light, green light, and red light are mixed to obtain white light, so it can be used as a backlight for a display.

[0147] 4. Light-emitting element Hereinafter, the case where the color filter pixel portion of the light-emitting element including the blue organic LED backlight is formed with the ink composition of the present invention will be described as an example. FIG. 2 is a cross-sectional view showing an embodiment of a light-emitting element including a light conversion layer made of a cured product of the ink composition of the present invention, and FIGS. 3 and 4 are schematic views showing the configuration of an active matrix circuit, respectively. In FIG. 2, for convenience, the dimensions and their ratios of each part are exaggerated and may be different from the actual ones. Further, the materials, dimensions, etc. shown below are examples, and the present invention is not limited thereto and can be appropriately changed without changing the gist thereof. Hereinafter, for convenience of explanation, the upper side of FIG. 2 is referred to as "upper side" or "above", and the lower side is referred to as "lower side" or "below". In FIG. 2, the description of the hatching indicating the cross section is omitted to avoid complication of the drawing.

[0148] As shown in FIG. 2, the light-emitting element 100 has a structure in which a lower substrate 1, an EL light source unit 200, a filling layer 10, a protective layer 11, a light conversion layer 12 containing the light-emitting powder of the present invention and acting as a light-emitting layer, and an upper substrate 13 are laminated in this order. Here, the surface layer including the first luminescent particles and the second luminescent particles constituting the light-emitting powder and having a siloxane bond in each of the first semiconductor nanocrystal and the second semiconductor nanocrystal may have one layer having a siloxane bond or may have a plurality of layers.

[0149] The EL light source unit 200 sequentially includes an anode 2, an EL layer 14 composed of a plurality of layers, a cathode 8, a polarizing plate (not shown), and a sealing layer 9. The EL layer 14 includes a hole injection layer 3, a hole transport layer 4, a light-emitting layer 5, an electron transport layer 6, and an electron injection layer 7 laminated in order from the anode 2 side. Such a light-emitting element 100 is a photoluminescence element that absorbs and re-emits or transmits the light emitted from the EL light source unit 200 (EL layer 14) by the light conversion layer 12 and extracts it to the outside from the upper substrate 13 side. At this time, the light is converted into light of a predetermined color by the light-emitting powder contained in the light conversion layer 12. Hereinafter, each layer will be sequentially described.

[0150] [Lower substrate 1 and upper substrate 13] The lower substrate 1 and the upper substrate 13 each have a function of supporting and / or protecting each layer constituting the light-emitting element 100. When the light-emitting element 100 is a top emission type, the upper substrate 3 is composed of a transparent substrate. On the other hand, when the light-emitting element 100 is a bottom emission type, the lower substrate 2 is composed of a transparent substrate. Here, the transparent substrate means a substrate capable of transmitting light having a wavelength in the visible light region, and transparency includes colorless transparency, colored transparency, and semi-transparency.

[0151] As the transparent substrate, for example, glass substrates such as quartz glass and synthetic quartz plates; quartz substrates; resin substrates composed of polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyimide, polycarbonate, etc.; metal substrates composed of iron, stainless steel, aluminum, copper, etc.; silicon substrates, gallium arsenide substrates, etc. can be used. Among them, a glass substrate made of alkali-free glass containing no alkali component is preferable from the viewpoints of small thermal expansion coefficient, excellent dimensional stability, and workability in high-temperature heat treatment. As such a glass substrate, for example, "7059 glass", "1737 glass", "Eagle 2000", and "Eagle XG (registered trademark)" manufactured by Corning Incorporated, "AN100" manufactured by Asahi Glass Co., Ltd., "OA-10G" and "OA-11" manufactured by Nippon Electric Glass Co., Ltd. can be preferably used. There is no particular limitation on the average thickness of the lower substrate 1 and the upper substrate 13, and usually, a range of 100 to 1000 μm is preferable, and a range of 300 to 800 μm is more preferable. When imparting flexibility to the light-emitting element 100, a resin substrate or a metal substrate having a relatively small thickness can be selected for the lower substrate 1 and the upper substrate 13, respectively. Note that depending on the usage form of the light-emitting element 100, one or both of the lower substrate 1 and the upper substrate 13 may be omitted.

[0152] As shown in FIG. 3, on the lower substrate 1, there are provided a signal line driving circuit C1 and a scanning line driving circuit C2 that control the supply of current to the anode 2 constituting the pixel electrodes PE indicated by R, G, and B, a control circuit C3 that controls the operation of these circuits, a plurality of signal lines 706 connected to the signal line driving circuit C1, and a plurality of scanning lines 707 connected to the scanning line driving circuit C2. Also, as shown in FIG. 4, near the intersection of each signal line 706 and each scanning line 707, a capacitor 701, a driving transistor 702, and a switching transistor 708 are provided.

[0153] One electrode of the capacitor 701 is connected to the gate electrode of the driving transistor 702, and the other electrode is connected to the source electrode of the driving transistor 702. The driving transistor 702 has its gate electrode connected to one electrode of the capacitor 701, its source electrode connected to the other electrode of the capacitor 701 and the power supply line 703 that supplies the driving current, and its drain electrode connected to the anode 2 of the EL light source unit 200.

[0154] The switching transistor 708 has its gate electrode connected to the scanning line 707, its source electrode connected to the signal line 706, and its drain electrode connected to the gate electrode of the driving transistor 702. Also, in this embodiment, the common electrode 705 constitutes the cathode 8 of the EL light source unit 200. Note that the driving transistor 702 and the switching transistor 708 can be formed of, for example, thin film transistors or the like.

[0155] The scanning line driving circuit C2 supplies or cuts off a scanning voltage corresponding to the scanning signal to the gate electrode of the switching transistor 708 via the scanning line 707, turning the switching transistor 708 on or off. Thereby, the scanning line driving circuit C2 adjusts the timing at which the signal line driving circuit C1 writes the signal voltage. On the other hand, the signal line driving circuit C1 supplies or cuts off a signal voltage corresponding to the video signal to the gate electrode of the driving transistor 702 via the signal line 706 and the switching transistor 708, adjusting the amount of the signal current supplied to the EL light source unit 200.

[0156] Therefore, when a scanning voltage is supplied from the scanning line driving circuit C2 to the gate electrode of the switching transistor 708 and the switching transistor 708 is turned on, a signal voltage is supplied from the signal line driving circuit C1 to the gate electrode of the switching transistor 708. At this time, a drain current corresponding to this signal voltage is supplied from the power supply line 703 to the EL light source unit 200 as a signal current. As a result, the EL light source unit 200 emits light according to the supplied signal current.

[0157] <EL light source unit 200> [Anode 2] The anode 2 has a function of supplying holes from an external power source toward the light emitting layer 5. Examples of the constituent material (anode material) of the anode 2 include metals such as gold and aluminum; metal halides such as copper iodide; metal oxides such as indium tin oxide (ITO), tin oxide (SnO2), and zinc oxide (ZnO); and the like. These may be used alone or in combination of two or more. There is no particular limitation on the average thickness of the anode 2, and usually, a range of 10 to 1000 nm is preferable, and a range of 10 to 200 nm is more preferable. The anode 2 can be formed by a dry film forming method such as a vacuum evaporation method or a sputtering method. At this time, the anode 2 having a predetermined pattern may be formed by a photolithography method or a method using a mask.

[0158] [Cathode 8] The cathode 8 has a function of supplying electrons from an external power source toward the light emitting layer 5. Examples of the constituent material (cathode material) of the cathode 8 include metals or metal oxides such as lithium, sodium, magnesium, aluminum, silver, sodium - potassium alloy, magnesium / aluminum mixture, magnesium / silver mixture, magnesium / indium mixture, aluminum / aluminum oxide mixture, rare earth metals, ITO, aluminum - doped zinc oxide (AZO), SnO2, and ZnO. These may be used alone or in combination of two or more. There is no particular limitation on the average thickness of the cathode 8, and usually, the range of 0.1 to 1000 nm is preferable, and the range of 1 to 200 nm is more preferable. The cathode 8 can be formed by a dry film formation method such as a vapor deposition method or a sputtering method. When the light-emitting element 100 is a top emission type, the cathode 8 is composed of a transparent electrode formed of ITO or the like. In this case, the anode 2 may be composed of a reflective electrode formed of aluminum or the like. On the other hand, when the light-emitting element 100 is a bottom emission type, the anode 2 is composed of a transparent electrode formed of ITO or the like. In this case, the cathode 8 may be composed of a reflective electrode formed of aluminum or the like.

[0159] [Hole injection layer 3] The hole injection layer 3 has a function of receiving holes supplied from the anode 2 and injecting them into the hole transport layer 4. Note that the hole injection layer 3 may be provided as necessary or may be omitted. Examples of the constituent material (hole injection material) of the hole injection layer 3 include phthalocyanine compounds such as copper phthalocyanine; triphenylamine derivatives such as 4,4’,4’’-tris[phenyl(m-tolyl)amino]triphenylamine; cyano compounds such as 1,4,5,8,9,12-hexaazatriphenylene hexacarbonitrile and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-quinodimethane; metal oxides such as vanadium oxide and molybdenum oxide; amorphous carbon; polymers such as polyaniline (emeraldine), poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) (PEDOT-PSS), and polypyrrole. These may be used alone or in combination of two or more. Among them, PEDOT-PSS is more preferable.

[0160] There is no particular limitation on the average thickness of the hole injection layer 3, and usually, the range of 0.1 to 500 nm is preferable, the range of 1 to 300 nm is more preferable, and the range of 2 to 200 nm is even more preferable. Also, the hole injection layer 3 may be a single layer or a laminated structure in which two or more layers are laminated. The positive hole injection layer 3 can be formed by a wet film forming method or a dry film forming method. In the wet film forming method, usually, a liquid composition containing a positive hole injection material is applied by an inkjet printing method (a piezo method or a thermal type droplet ejection method), a spin coating method, a casting method, an LB method, a relief printing method, a gravure printing method, a screen printing method, a nozzle printing method, etc., and the obtained coating film is dried. Note that the nozzle printing method is a method of applying a liquid composition as a liquid column in a stripe shape from a nozzle hole. As the dry film forming method, a vacuum evaporation method, a sputtering method, etc. can be preferably used.

[0161] [Positive hole transport layer 4] The positive hole transport layer 4 has a function of receiving positive holes from the positive hole injection layer 3 and efficiently transporting them to the light emitting layer 5. Further, the positive hole transport layer 4 may have a function of preventing the transport of electrons. Note that the positive hole transport layer 4 may be provided as necessary and can also be omitted.

[0162] As the constituent material (positive hole transport material) of the positive hole transport layer 4, it is preferable to use a material having a higher positive hole transport ability than the electron transport ability. Examples of such positive hole transport materials include aromatic amines, carbazole derivatives, aromatic hydrocarbons, stilbene derivatives, etc., and π-electron excess type heteroaromatics or aromatic amines, etc. can be preferably used. Specific examples of the hole transport material include triphenylamine derivatives such as TPD (N,N'-diphenyl-N,N'-di(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine), α-NPD (4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl), m-MTDATA (4,4',4''-tris(3-methylphenylphenylamino)triphenylamine); polyvinylcarbazole; conjugated compound polymers such as poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine] (poly-TPA), polyfluorene (PF), poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine] (Poly-TPD), poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-[4,4'-(N-(sec-butylphenyl)diphenylamine)]] (TFB), polyphenylene vinylene (PPV); and copolymers containing these monomer units. These may be used alone or in combination of two or more. As the hole transport material, triphenylamine derivatives, polymers or copolymers of triphenylamine derivatives into which substituents are introduced are preferable, and polymers of triphenylamine derivatives into which substituents are introduced are more preferable.

[0163] There is no particular limitation on the average thickness of the hole transport layer 4, and usually, a range of 1 to 500 nm is preferable, a range of 5 to 300 nm is more preferable, and a range of 10 to 200 nm is even more preferable. The hole transport layer 4 may be a single layer or a laminated structure in which two or more layers are laminated. Such a hole transport layer 4 can be formed by a wet film formation method or a dry film formation method. The wet film formation method and the dry film formation method are as described above in the description of the hole injection layer 3.

[0164] [Electron injection layer 7] The electron injection layer 7 has a function of receiving electrons supplied from the cathode 8 and injecting them into the electron transport layer 6. Note that the electron injection layer 7 may be provided as necessary or omitted. Examples of the constituent material (electron injection material) of the electron injection layer 7 include alkali metal chalcogenides such as Li2O, LiO, Na2S, Na2Se, and NaO; alkaline earth metal chalcogenides such as CaO, BaO, SrO, BeO, BaS, MgO, and CaSe; alkali metal halides such as CsF, LiF, NaF, KF, LiCl, KCl, and NaCl; alkali metal salts such as lithium 8-hydroxyquinolinate (Liq); and alkaline earth metal halides such as CaF2, BaF2, SrF2, MgF2, and BeF2. These may be used alone or in combination of two or more. Among them, alkali metal chalcogenides, alkaline earth metal halides, and alkali metal salts are preferred.

[0165] There is no particular limitation on the average thickness of the electron injection layer 7. Usually, the range of 0.1 to 100 nm is preferred, the range of 0.2 to 50 nm is more preferred, and the range of 0.5 to 10 nm is even more preferred. Also, the electron injection layer 7 may be a single layer or a laminated structure in which two or more layers are laminated. The electron injection layer 7 can be formed by a wet film-forming method or a dry film-forming method. The wet film-forming method and the dry film-forming method are as described above in the description of the hole injection layer 3.

[0166] [Electron transport layer 6] The electron transport layer 6 has a function of receiving electrons from the electron injection layer 7 and efficiently transporting them to the light-emitting layer 5. Also, the electron transport layer 6 may have a function of preventing the transport of holes. Note that the electron transport layer 6 may be provided as necessary or may be omitted. As the constituent material (electron transport material) of the electron transport layer 6, it is preferable to use a material having a higher electron transport ability than a hole transport ability. Examples of the electron transport material include π-electron deficient heteroaromatics such as nitrogen-containing heteroaromatic compounds such as fullerene, diphenylquinone derivatives, nitro-substituted fluorene derivatives, quinoxaline derivatives, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, pyridine derivatives, bipyridine derivatives, imidazole derivatives, quinoline derivatives, perylene derivatives, triazine derivatives, or pyrimidine derivatives; metal complexes having a quinoline ligand, a perylene ligand, a benzoquinoline ligand, an oxazole ligand, a benzoxazoline ligand, a benzothiazoline ligand, or a thiazole ligand, and the like.

[0167] Specific examples of the electron transport material include tris(8-quinolinolato)aluminum (Alq), tris(4-methyl-8-quinolinolato)aluminum (Almq3), bis(10-hydroxybenzo[h]quinolinato)beryllium, bis(2-methyl-8-quinolinolato)(p-phenylphenolato)aluminum, bis(8-quinolinolato)zinc, bis[2-(2'-hydroxyphenyl)benzoxazolato]zinc, bis[2-(2'-hydroxyphenyl)benzothiazolato]zinc, 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (TAZ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]carbazole (CO11), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (mDBTBIm-II), 4,7-diphenyl-1,10-phenanthroline (BPhen), and the like. These compounds may be used alone or in combination of two or more. In addition, an inorganic semiconductor material may be used as the electron transport material. By forming the electron transport layer 6 with an inorganic semiconductor material, the mobility of electrons in the electron transport layer 6 can be increased, and the injection efficiency of electrons into the light-emitting layer 5 can be improved. Examples of such electron transport materials include metal salts such as cesium carbonate; titanium oxide (TiO x ), metal oxides such as zinc oxide can be preferably used.

[0168] There is no particular limitation on the average thickness of the electron transport layer 6, and usually, a range of 5 to 500 nm is preferable, and a range of 5 to 200 nm is more preferable. Further, the electron transport layer 6 may be a single layer or a laminated structure in which two or more layers are laminated. The electron transport layer 6 can be formed by a wet film-forming method or a dry film-forming method. The wet film-forming method and the dry film-forming method are as described above in the description of the hole injection layer 3.

[0169] When the hole injection layer 3 and the electron injection layer 7 are provided in the light-emitting device 100, the transport efficiency of holes and electrons to the light-emitting layer 5 through the hole transport layer 4 and the electron transport layer 6 can be increased. As a result, the light-emitting efficiency of the light-emitting layer 5 can be further improved, and a light-emitting device capable of emitting light with high luminance and having a long life can be obtained.

[0170] [Light-emitting layer 5] The light-emitting layer 5 has a function of generating light by using the energy generated by the recombination of holes and electrons injected into the light-emitting layer 5. The light-emitting layer 5 of the present embodiment emits blue light having a wavelength in the range of 400 to 500 nm, and more preferably in the range of 420 to 480 nm. The light-emitting layer 5 preferably contains a light-emitting material (guest material or dopant material) and a host material. There is no particular limitation on the mass ratio of the host material to the light-emitting material, and usually, a range of 10:1 to 300:1 is preferable. As the light-emitting material, a compound capable of converting singlet excitation energy into light or a compound capable of converting triplet excitation energy into light can be used, and preferably contains at least one selected from the group consisting of organic low-molecular fluorescent materials, organic high-molecular fluorescent materials, and organic phosphorescent materials.

[0171] Examples of compounds capable of converting singlet excitation energy into light include organic low-molecular-weight fluorescent materials or organic high-molecular-weight fluorescent materials that emit fluorescence. As the organic low-molecular-weight fluorescent material, compounds having an anthracene structure, a tetracene structure, a chrysene structure, a phenanthrene structure, a pyrene structure, a perylene structure, a stilbene structure, an acridone structure, a coumarin structure, a phenoxazine structure, or a phenothiazine structure are preferable.

[0172] Specific examples of the organic low-molecular-weight fluorescent material include, for example, 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine, 5,6-bis[4'-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2'-bipyridine, N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine, 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine, 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine, N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine, 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine, 4-[4-(10-phenyl-9-anthryl)phenyl]-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine, perylene, 2,5,8,11-tetra(tert-butyl)perylene, N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine, N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]-pyrene-1,6-diamine, N,N'-bis(dibenzofuran-2-yl)-N,N'-diphenylpyrene-1,6-diamine, N,N'-bis(dibenzothiophen-2-yl)-N,N'-diphenylpyrene-1,6-diamine, N,N''-(2-tert-butylanthracene-9,10-diyl-di-4,1-phenylene)bis[N,N',N'-triphenyl-1,4-phenylenediamine], N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole-3-amine, N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine, N,N,N',N',N'',N'',N''',N''' -octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine, coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9-Diphenyl-9H-carbazol-3-amine, N-(9,10-diphenyl-2-anthryl)-N,N’,N’-triphenyl-1,4-phenylenediamine, N,N,9-triphenylanthracen-9-amine, Coumarin 6, Coumarin 545T, N,N’-diphenylquinacridone, Rubrene, 5,12-bis(1,1’-biphenyl-4-yl)-6,11-diphenyltetracene, 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-ylidene)propanedinitrile, 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile, N,N,N’,N’-tetrakis(4-methylphenyl)tetracene-5,11-diamine, 7,14-diphenyl-N,N,N’,N’-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine, 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile, 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile, 2-(2,6-bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile, 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile, 5,10,15,20-tetraphenylbisbenzo[5,6]inden[1,2,3-cd:1’,2’,3’-lm]perylene, etc. are mentioned.,

[0173] Examples of the organic polymer fluorescent material include a homopolymer composed of units based on a fluorene derivative, a copolymer composed of units based on a fluorene derivative and units based on a tetraphenylphenylenediamine derivative, a homopolymer composed of units based on a terphenyl derivative, a homopolymer composed of units based on a diphenylbenzofluorene derivative, and the like.

[0174] As the compound capable of converting triplet excitation energy into light, an organic phosphorescent material that emits phosphorescence is preferable. Examples of the organic phosphorescent material include metal complexes containing at least one metal atom selected from the group consisting of Ir, Rh, Pt, Ru, Os, Sc, Y, Gd, Pd, Ag, Au, and Al. Among them, metal complexes containing at least one metal atom selected from the group consisting of Ir, Rh, Pt, Ru, Os, Sc, Y, Gd, and Pd are preferable, metal complexes containing at least one metal atom selected from the group consisting of Ir, Rh, Pt, and Ru are more preferable, and Ir complexes or Pt complexes are even more preferable.

[0175] The light-emitting layer 5 may contain a host material. The host material provides a site for the recombination of holes and electrons injected into the light-emitting layer 5 and promotes the formation of hole-electron pairs (excitons) on its molecules. The excitation energy of this exciton moves to the nanocrystals (Förster resonance energy transfer) and emits light. By utilizing such a phenomenon, the light emission efficiency of the light-emitting layer 5 can be improved. As the host material, it is preferable to use at least one compound having an energy gap larger than the energy gap of the light-emitting material. When the light-emitting material is a phosphorescent material, it is preferable to select a compound having a larger triplet excitation energy (energy difference between the ground state and the triplet excited state) than the light-emitting material as the host material.

[0176] Examples of host materials include Alq, Almq3, bis(10-hydroxybenzo[h]quinolinato)beryllium(II), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III), bis(8-quinolinolato)zinc(II), bis[2-(2-benzoxazolyl)phenolato]zinc(II), bis[2-(2-benzothiazolyl)phenolato]zinc(II), 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole, 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene, 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole, 2,2’,2’’-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole), bathophenanthroline, bathocuproine, 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole, 9,10-diphenylanthracene, N,N-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine, 4-(10-phenyl-9-anthryl)triphenylamine, N,9-diphenyl-N-{4-[4-(10-phenyl-9-anthryl)phenyl]phenyl}-9H-carbazole-3-amine, 6,12-dimethoxy-5,11-diphenylchrysene, 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole, 3,6-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole, 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole, 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole, 6-[3-(9,10-diphenyl-2-anthryl)phenyl]-benzo[b]naphtho[1,2-d]furan, 9-phenyl-10-{4-(9-phenyl-9H-fluoren-9-yl)biphenyl-4’-yl}anthracene, 9,10-bis(3,5-diphenylphenyl)anthracene, 9,10-di(2-naphthyl)anthracene, 2-tert-butyl-9,Examples include 10-di(2-naphthyl)anthracene, 9,9'-bianthryl, 9,9'-(stilbene-3,3'-diyl)diphenanthrene, 9,9'-(stilbene-4,4'-diyl)diphenanthrene, 1,3,5-tri(1-pyrenyl)benzene, 5,12-diphenyltetracene, or 5,12-bis(biphenyl-2-yl)tetracene. These may be used alone or in combination of two or more kinds.,

[0177] The average thickness of the light-emitting layer 5 is usually preferably in the range of 1 to 100 nm, and more preferably in the range of 1 to 50 nm. The light-emitting layer 5 can be formed by a wet film-forming method or a dry film-forming method. The wet film-forming method and the dry film-forming method are as described above in the description of the hole injection layer 3.

[0178] Note that the EL light source unit 200 may further have, for example, a bank (partition wall) that partitions the hole injection layer 3, the hole transport layer 4, and the light-emitting layer 5. The height of the bank is not particularly limited, and is usually preferably in the range of 0.1 to 5 μm, more preferably in the range of 0.2 to 4 μm, and even more preferably in the range of 0.2 to 3 μm. The width of the opening of the bank is preferably in the range of 10 to 200 μm, more preferably in the range of 30 to 200 μm, and even more preferably in the range of 50 to 100 μm. The length of the opening of the bank is preferably in the range of 10 to 400 μm, more preferably in the range of 20 to 200 μm, and even more preferably in the range of 50 to 200 μm. Also, the inclination angle of the bank is preferably in the range of 10 to 100°, more preferably in the range of 10 to 90°, and even more preferably in the range of 10 to 80°.

[0179] The light-emitting element 100 may further have a hole-blocking layer between the light-emitting layer 5 and the electron-transporting layer 6. The hole-blocking layer has a function of regulating the holes transported from the hole-transporting layer 4 from passing through the light-emitting layer 5 and moving to the electron-transporting layer 6. When a hole-blocking layer is provided, holes that could not recombine with electrons in the light-emitting layer 5 can be retained in the light-emitting layer 5 without escaping to the electron-transporting layer 6. The holes remaining in the light-emitting layer 5 can obtain another opportunity to recombine with electrons, so they are not wasted, and the luminous efficiency of the light-emitting layer 5 can be further improved. As the constituent material of the hole-blocking layer, the above-described electron-transporting materials can be used singly or in combination of two or more. There is no particular limitation on the average thickness of the hole-blocking layer. Usually, a range of 1 to 500 nm is preferable, a range of 2 to 300 nm is more preferable, and a range of 3 to 200 nm is even more preferable. Also, the hole-blocking layer may be a single layer or a laminated structure in which two or more layers are laminated. The hole-blocking layer can be formed by a wet film-forming method or a dry film-forming method. The wet film-forming method and the dry film-forming method are as described above in the explanation of the hole-injecting layer 3. Further, the light-emitting element 100 may further have a reflective layer for appropriately reflecting light, a transparent optical adjustment layer for appropriately transmitting light, and a light-scattering layer for appropriately transmitting and scattering light. The embodiment of the light-emitting element 100 is not limited to the above-described configuration, and other arbitrary configurations may be additionally provided, or may be replaced with any configuration that exhibits the same function.

[0180] <Light conversion layer 12> The light conversion layer 12 converts the light emitted from the EL light source unit 200 and re-emits it, or transmits the light emitted from the EL light source unit 200. As shown in FIG. 2, the light conversion layer has, as a pixel portion 20, a first pixel portion 20a that converts light of the wavelength within the above range to emit red light, a second pixel portion 20b that converts light of the wavelength within the above range to emit green light, and a third pixel portion 20c that transmits light of the wavelength within the above range. A plurality of the first pixel portions 20a, the second pixel portions 20b, and the third pixel portions 20c are arranged in a lattice pattern so as to repeat in this order. And between adjacent pixel portions, that is, between the first pixel portion 20a and the second pixel portion 20b, between the second pixel portion 20b and the third pixel portion 20c, and between the third pixel portion 20c and the first pixel portion 20a, a light-shielding portion 30 that shields light is provided. In other words, adjacent pixel portions 20 are separated by the light-shielding portion 30. Note that the first pixel portion 20a and the second pixel portion 20b may each contain a colorant corresponding to each color.

[0181] The first pixel portion 20a and the second pixel portion 20b are light-emitting pixel portions each containing a cured product of the above-described ink composition. The cured product contains a light-emitting powder and a curing component. Further, the cured product preferably further contains light-scattering particles in order to scatter light and surely extract it to the outside. The first pixel portion 20a includes a first curing component 22a, and a first light-emitting powder 90a and first light-scattering particles 21a dispersed in the first curing component 22a. Similarly, the second pixel portion 20b includes a second curing component 22b, and a second light-emitting powder 90b and second light-scattering particles 21b dispersed in the second curing component 22b. Note that the first light-emitting powder 90a actually contains a first light-emitting particle and a second light-emitting particle, but the description of each light-emitting particle is omitted in FIG. 2. Similarly, the second light-emitting powder 90b actually contains a first light-emitting particle and a second light-emitting particle, but the description of each light-emitting particle is omitted in FIG. 2. The curing component is a component obtained by polymerization of a photopolymerizable compound, and may contain a polymer of the photopolymerizable compound and organic components (dispersant, unreacted photopolymerizable compound, etc.) in the ink composition. In the first pixel portion 20a and the second pixel portion 20b, the first curing component 22a and the second curing component 22b may be the same or different, and the first light-scattering particles 21a and the second light-scattering particles 21b may be the same or different.

[0182] The first light-emitting powder 90a is a red light-emitting powder that absorbs light having a wavelength in the range of 420 to 480 nm and emits light having a peak wavelength of the emission spectrum in the range of 605 to 665 nm. That is, the first pixel portion 20a can be said to be a red pixel portion for converting blue light into red light. Further, the second light-emitting powder 90b is a green light-emitting powder that absorbs light having a wavelength in the range of 420 to 480 nm and emits light having a peak wavelength of the emission spectrum in the range of 500 to 560 nm. That is, the second pixel portion 20b can be said to be a green pixel portion for converting blue light into green light.

[0183] From the viewpoints of excellent external quantum efficiency improvement effect and excellent emission intensity, the content of the light-emitting powder in the pixel portions 20a and 20b is preferably 0.1% by mass or more, more preferably 1% by mass or more, further preferably 2% by mass or more, and particularly preferably 3% by mass or more based on the total mass of the cured product of the ink composition. From the viewpoints of excellent reliability of the pixel portions 20a and 20b and excellent emission intensity, the content of the light-emitting powder is preferably 30% by mass or less, more preferably 25% by mass or less, further preferably 20% by mass or less, and particularly preferably 15% by mass or less based on the total mass of the ink composition.

[0184] The content of the light-scattering particles in the pixel portions 20a and 20b is preferably 0.1% by mass or more, more preferably 1% by mass or more, still more preferably 5% by mass or more, and particularly preferably 7% by mass or more, based on the total mass of the cured product of the ink composition, from the viewpoint of excellent external quantum efficiency improvement effect. The content of the light-scattering particles is preferably 60% by mass or less, more preferably 50% by mass or less, still more preferably 40% by mass or less, and particularly preferably 30% by mass or less, based on the total mass of the cured product of the ink composition, from the viewpoints of excellent external quantum efficiency improvement effect and excellent reliability of the pixel portion 20.

[0185] The third pixel portion 20c has a transmittance of 30% or more with respect to light having a wavelength in the range of 420 to 480 nm. Therefore, the third pixel portion 20c functions as a blue pixel portion when using a light source that emits light having a wavelength in the range of 420 to 480 nm. The third pixel portion 20c is a non-luminous pixel portion including a cured product of a composition (non-luminous ink composition) having the same composition as the ink composition of the above-described embodiment except that it does not contain the light-emitting powder of the present invention. The cured product does not contain a light-emitting powder and contains light-scattering particles and a curing component. That is, the third pixel portion 20c includes a third curing component 22c and third light-scattering particles 21c dispersed in the third curing component 22c. The third curing component 22c is, for example, a component obtained by polymerization of a photopolymerizable compound and includes a polymer of the photopolymerizable compound. The third curing component 22c may contain a polymer of a photopolymerizable compound and organic components (dispersant, unreacted photopolymerizable compound, etc.) in the ink composition as long as the transmittance with respect to light having a wavelength in the range of 420 to 480 nm is 30% or more. The third light-scattering particles 21c may be the same as or different from the first light-scattering particles 21a and the second light-scattering particles 21b. The content of the light-scattering particles in the pixel portion 20c is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more based on the total mass of the cured product of the non-light-emitting ink composition from the viewpoint of further reducing the light intensity difference at the viewing angle. The content of the light-scattering particles is preferably 80% by mass or less, more preferably 75% by mass or less, and even more preferably 70% by mass or less based on the total mass of the cured product of the non-light-emitting ink composition from the viewpoint of further reducing light reflection. Note that the transmittance of the third pixel portion 20c can be measured by a microscopic spectroscopic device.

[0186] The thickness of the pixel portion (the first pixel portion 20a, the second pixel portion 20b, and the third pixel portion 20c) is preferably 1 μm or more, more preferably 2 μm or more, and even more preferably 3 μm or more. The thickness of the pixel portion (the first pixel portion 20a, the second pixel portion 20b, and the third pixel portion 20c) is preferably 30 μm or less, more preferably 25 μm or less, and even more preferably 20 μm or less.

[0187] The light-shielding portion 30 is a partition wall portion, a so-called black matrix, provided for the purpose of preventing color mixing (crosstalk) between adjacent pixel portions 20 and preventing light leakage from the light source. The material constituting the light-shielding portion 30 is not particularly limited, and examples include resins containing light-shielding particles such as carbon fine particles, metal oxides, inorganic pigments, and organic pigments in addition to metals such as chromium, and resin compositions. Examples of the binder resin include resins containing one or more of polyimide resin, acrylic resin, epoxy resin, polyacrylamide, polyvinyl alcohol, gelatin, casein, cellulose, etc., photosensitive resins, O / W emulsion resins (for example, reactive silicone emulsions), and the like. The thickness of the light-shielding portion 30 is preferably 1 μm or more and 15 μm or less.

[0188] [Method for forming the light conversion layer 12] The light conversion layer 12 including the above-described first to third pixel portions 20a to 20c can be formed, for example, by drying and heating a coating film formed by a wet film-forming method to cure it. The first pixel portion 20a and the second pixel portion 20b can be formed using the ink composition of the present invention, and the third pixel portion 20c can be formed using the non-luminescent ink composition described above that does not contain the luminescent powder of the present invention.

[0189] As a coating method for obtaining a coating film of the ink composition of the present invention, an inkjet printing method (a droplet ejection method of a piezo method or a thermal method), a spin coating method, a casting method, an LB method, a relief printing method, a gravure printing method, a screen printing method, a nozzle printing method, etc. can be mentioned. As the coating method, an inkjet printing method (particularly, a droplet ejection method of a piezo method) is preferable. Thereby, the heat load at the time of ejecting the ink composition can be reduced, and deterioration of the luminescent powder due to heat can be prevented.

[0190] In the inkjet printing method, the ejection amount of the ink composition is not particularly limited, and usually, it is preferably 1 to 50 pL / time, more preferably 1 to 30 pL / time, and even more preferably 1 to 20 pL / time. The opening diameter of the nozzle hole is preferably in the range of 5 to 50 μm, and more preferably in the range of 10 to 30 μm. When it is in such a range, the clogging of the nozzle hole can be prevented while the ejection accuracy of the ink composition can be improved.

[0191] The temperature at the time of forming the coating film is not particularly limited, and usually, the range of 10 to 50°C is preferable, the range of 15 to 40°C is more preferable, and the range of 15 to 30°C is even more preferable. If droplets are ejected at such a temperature, crystallization of various components contained in the ink composition of the present invention can be suppressed. Also, the relative humidity during film formation is not particularly limited, and it is usually preferably in the range of 0.01 ppm to 80%, more preferably in the range of 0.05 ppm to 60%, still more preferably in the range of 0.1 ppm to 15%, particularly preferably in the range of 1 ppm to 1%, and most preferably in the range of 5 to 100 ppm. When the relative humidity is at or above the above lower limit value, it becomes easier to control the conditions during film formation. On the other hand, when the relative humidity is at or below the above upper limit value, the amount of moisture adsorbed on the coating film that may adversely affect the obtained light conversion layer 12 can be reduced.

[0192] When hydrocarbons, halogenated hydrocarbons, ethers, alcohols, ketones, esters, aprotic polar compounds, etc. are added as solvents to the ink composition, after the ink composition is applied on a substrate and before curing, drying is performed under natural drying, heating, or reduced pressure. From the viewpoint of productivity, it is preferable to perform drying under heating or under heating and reduced pressure. The heating temperature is usually preferably 50 to 130°C, more preferably 60 to 120°C, taking into account the boiling point and vapor pressure of the added solvent. The pressure under reduced pressure is usually preferably in the range of 0.001 to 100 Pa. Also, the drying time is usually preferably 1 to 30 minutes. By removing the solvent from the coating film by drying, the external quantum efficiency of the obtained light conversion layer can be further improved.

[0193] Curing of the ink composition of the present invention can be performed by irradiation with active energy rays (for example, ultraviolet rays). Examples of the irradiation source (light source) include a mercury lamp, a metal halide lamp, a xenon lamp, an LED, etc., and an LED is preferable from the viewpoints of reducing the heat load on the coating film and low power consumption.

[0194] The wavelength of the light to be irradiated is preferably 200 nm or more and 440 nm or less. Also, the light intensity is preferably 0.2 to 2 kW / cm 2 from the viewpoint that the curing degree of the coating film surface and inside is uniform and can be sufficiently cured, and it is easy to maintain the smoothness of the coating film surface, and more preferably 0.4 to 1 kW / cm 2 . The light irradiation amount (exposure amount) is preferably 10 mJ / cm 2 or more and 4000 mJ / cm 2 or less. The curing of the coating film can be carried out in an air atmosphere or in an inert gas atmosphere such as nitrogen, argon, carbon dioxide, etc. However, from the viewpoint of suppressing oxygen inhibition on the coating film surface and oxidation of the coating film, it is preferably carried out under an inert gas. By curing the coating film under such conditions, the external quantum efficiency of the obtained light conversion layer can be further improved.

[0195] As described above, since the ink composition of the present invention is excellent in thermal stability, good light emission can also be realized in the pixel portion 20 which is a cured product (molded body). Further, since the ink composition of the present invention is excellent in dispersibility, it is excellent in the dispersibility of the light-emitting powder, and it is easy to obtain a flat pixel portion 20.

[0196] Furthermore, when the light-emitting powder contained in the first pixel portion 20a and the second pixel portion 20b contains semiconductor nanocrystals having a perovskite crystal structure, the absorption in the wavelength region of 300 to 500 nm is large. Therefore, in the first pixel portion 20a and the second pixel portion 20b, it is possible to prevent the blue light incident on the first pixel portion 20a and the second pixel portion 20b from transmitting to the upper substrate 13 side, that is, to prevent the blue light from leaking to the upper substrate 13 side. Therefore, according to the first pixel portion 20a and the second pixel portion 20b containing the light-emitting powder of the present invention, red light and green light with high color purity can be extracted without color mixing of the blue light.

[0197] Instead of the top emission type, the light-emitting element 100 can also be configured as a bottom emission type. Further, instead of the EL light source portion 200, the light-emitting element 100 can also use other light sources.

[0198] The above-described light-emitting element is suitable for application to a color display device provided with a color filter. Here, the color display device is, for example, a device that performs color display such as a television, a monitor, a smartphone, a mobile phone, etc., and includes both a type that does not use a liquid crystal layer and a type that uses a liquid crystal layer.

[0199] As described above, the light-emitting particles of the present invention, the ink composition containing the light-emitting particles, the light conversion layer composed of the cured product of the ink composition, and the wavelength conversion film and the color filter provided with the light conversion layer have been described. However, the present invention is not limited to the configurations of the above-described embodiments. For example, the light-emitting particles of the present invention, the ink composition containing the light-emitting particles, the light conversion layer composed of the cured product of the ink composition, the wavelength conversion film provided with the light conversion layer, and the color filter may each have any other arbitrary configuration added in the configurations of the above-described embodiments, or may be replaced with any configuration that exhibits the same function. Further, the method for producing the light-emitting powder of the present invention may have any other arbitrary-purpose steps in the configurations of the above-described embodiments, or may be replaced with any steps that exhibit the same effects.

Examples

[0200] Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. Unless otherwise specified, "parts" and "%" are based on mass.

[0201] [Production Example 1] (Production Example of Polymer 1) 15 parts by mass of 12-hydroxystearic acid, 285 parts by mass of ε-caprolactone, and 0.05 parts by mass of monobutyltin oxide were charged into a reactor, and after the system was purged with nitrogen, it was heated to 120 °C and stirred for 4 hours to obtain a polyester intermediate. 100 parts by mass of a 10% aqueous solution of polyallylamine ("PAA (registered trademark)-1LV" (trade name), manufactured by Nitto Boseki Co., Ltd., number average molecular weight of about 3000) was charged into another reactor equipped with a water separation device and heated to 160 °C. To this, 200 parts by mass of the polyester intermediate obtained above, heated to 160 °C, was added, and the mixture was stirred at 160 °C for 2 hours while distilling off water to cause a reaction, thereby obtaining a graft copolymer (hereinafter referred to as "Polymer 1") that was a pale yellow solid at 25 °C. When the weight average molecular weight (Mw) of Polymer 1 was measured by gel permeation chromatography (GPC) under the following conditions, it was 44,000. <GPC Measurement Conditions> Device: 「HLC-8220GPC」(manufactured by Tosoh Corporation) Column: Two 「TSK-GEL super AWM-H」(manufactured by Tosoh Corporation) columns connected in series Eluent: N,N-dimethylformamide solution of lithium bromide (10 mmol / L) Flow rate: 0.6 mL / min Calibration curve: Standard polystyrene was used

[0202] [Production Example 2] (Production Example of Polymer 2) 6 parts by mass of polyethyleneimine (「Epomin (registered trademark) SP-018」(trade name, manufactured by Nippon Shokubai Co., Ltd.), 60 parts by mass of ε-caprolactone, 40 parts by mass of δ-valerolactone, 15 parts by mass of 12-hydroxystearic acid, and 0.05 parts by mass of dibutyltin dilaurate were charged into a reactor. After replacing the inside of the system with nitrogen, the mixture was heated to 170 °C and reacted for 5 hours to obtain a graft copolymer in the form of a brown liquid (hereinafter referred to as 「Polymer 2」). When the weight average molecular weight of Polymer 2 was measured by GPC in the same manner as in Production Example 1, it was 25,000.

[0203] [Production Example 3] (Production Example of Polymer 3) 66.5 parts by mass of lauryl methacrylate, 3.5 parts by mass of dimethylaminoethyl methacrylate, 0.5 parts by mass of dimethyl-2,2-azobis(2-methylpropionate), and 20 parts by mass of heptane were mixed to obtain a mixed solution. 190 parts by mass of heptane was charged into a four-necked flask equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen inlet tube, and the temperature was raised to 85 °C. The mixed solution obtained above was added dropwise thereto over 3.5 hours. After completion of the dropwise addition, the mixture was reacted at 85 °C for 10 hours to obtain a solution containing a copolymer (hereinafter referred to as 「Polymer 3」) (non-volatile content: 25.1% by mass). When the weight average molecular weight of Polymer 3 was measured by GPC in the same manner as in Production Example 1, it was 10,000.

[0204] [Production Example 4] (Preparation of Light Scattering Particle Dispersion) In a container filled with nitrogen gas, 10.0 parts by mass of titanium oxide (CR60-2 manufactured by Ishihara Sangyo Co., Ltd., average particle diameter 210 nm), 1.0 part by mass of a polymer dispersant “Efka PX4701” (amine value: 40.0 mgKOH / g, manufactured by BASF Japan Ltd.), and 14.0 parts by mass of phenoxyethyl acrylate (Light Acrylate POA; manufactured by Kyoeisha Chemical Co., Ltd.) were mixed. Further, zirconia beads (diameter: 1.25 mm) were added to the obtained formulation, the container was sealed, and the formulation was shaken for 2 hours using a paint conditioner to perform a dispersion treatment of the formulation, thereby obtaining a light-scattering particle dispersion. The average particle diameter of the light-scattering particles after the dispersion treatment was measured using a particle size distribution measuring device (NanoTrack Wave II) and was 0.245 μm.

[0205] (Production Examples of Luminescent Particles a and b) [Production Example 5 (Preparation of Dispersion Liquid a Containing Luminescent Particle a)] Under an argon atmosphere, 0.16 g of formamidine acetate and 5 mL of oleic acid were added to a three-necked flask, and the mixture was heated and stirred at 120 °C for 30 minutes under reduced pressure (15 ± 3 kPa). The pressure was returned to atmospheric pressure while maintaining the argon atmosphere. The temperature was raised to 150 °C and stirred until a uniform solution was obtained to obtain a formamidinium-oleic acid solution. On the other hand, under an argon atmosphere, 0.06 g of lead(II) bromide, 0.6 mL of oleic acid, and 7.85 mL of 1-octadecene were added to another three-necked flask different from the above, and the mixture was heated and stirred at 120 °C for 30 minutes under reduced pressure (15 ± 3 kPa). The pressure was returned to atmospheric pressure while maintaining the argon atmosphere, and 0.45 mL of 3-aminopropyltriethoxysilane (APTES; manufactured by Tokyo Chemical Industry Co., Ltd.) was added as a silane ligand T. The temperature was raised to 140 °C and stirred until a uniform solution was obtained.

[0206] 1.1 mL of the formamidinium-oleic acid solution was added to the obtained mixed solution containing lead(II) bromide at 150 °C, stirred for 5 seconds, and then cooled in an ice bath. Next, 30 mL of methyl acetate was added. After centrifuging the obtained suspension (10000 rpm, 3 minutes), 20 mL of toluene was added to the solid matter (luminescent particle a) obtained by removing the supernatant, and the mixture was shaken and stirred to disperse it. The obtained colloidal solution was centrifuged at 25 °C and 10,000 rpm for 3 minutes, and the supernatant was collected to obtain a dispersion liquid a in which the luminescent particles a were dispersed in a colloidal state. When X-ray powder analysis was performed on the luminescent particles a, it was found that the semiconductor nanocrystals constituting the luminescent particles a had a perovskite crystal structure of FAPbBr3 (where "FA" means (NH2)2CH, i.e., formamidinium). Also, regarding the luminescent particles a, the elemental distribution was evaluated by energy-dispersive X-ray analysis (STEM-EDS) using a scanning transmission electron microscope, and it was confirmed that Si was contained in the surface layer of the luminescent particles a. This Si is considered to be derived from the siloxane bond generated by the hydrolysis of APTES. Further, the dispersion liquid a was depressurized at 25 °C to evaporate the solvent to obtain a powder of the luminescent particles a, and when solid NMR of 29Si nuclei was measured, a peak indicating Si(T) was observed, but a peak indicating Si(Q) was not observed. Furthermore, regarding the luminescent particles a, the weight loss rate in the range of 100 to 470 °C was calculated by thermogravimetric differential thermal analysis (TG-DTA; heating rate 10 °C / min, under nitrogen atmosphere) measurement, and it was 46.7%. That is, in the dispersion liquid a, the luminescent particles a having FAPbBr3 with a perovskite crystal structure as the core and a surface layer containing a siloxane bond derived from a silane compound of the T unit are dispersed in a colloidal state. When the dispersion liquid a was analyzed by a particle size distribution measuring device (NanoTrac Wave II), its average particle size was 17 nm.

[0207] [Production Example 6 (Preparation of Dispersion Liquid b Containing Luminescent Particles b)] Under an argon atmosphere, 0.12 g of cesium carbonate, 5 mL of 1-octadecene, and 0.5 mL of oleic acid were added to a three-necked flask, and the mixture was heated and stirred at 120 °C for 30 minutes under reduced pressure (15 ± 3 kPa). It was returned to atmospheric pressure while maintaining the argon atmosphere. The temperature was raised to 150 °C and stirred until a uniform solution was obtained to obtain a cesium-oleic acid solution. On the one hand, under an argon atmosphere, 0.2 g of lead(II) bromide, 15 mL of 1-octadecene, and 1.5 mL of oleic acid were mixed in a three-necked flask different from the above. After drying under reduced pressure at 90 °C for 10 minutes, 1.5 mL of APTES was added as a silane ligand of T unit. After further drying under reduced pressure for 20 minutes, it was returned to atmospheric pressure while remaining under an argon atmosphere and heated at 140 °C. To the obtained mixed solution containing lead(II) bromide, 1.5 mL of the cesium-oleic acid solution was added at 150 °C, stirred for 5 seconds, and then cooled in an ice bath. Next, 30 mL of methyl acetate was added. After centrifuging the obtained suspension (10000 rpm, 1 minute), the supernatant was removed, and 20 mL of toluene was added to the obtained solid (luminescent particles b), and it was shaken and stirred to disperse. The obtained colloidal solution was centrifuged at 25 °C and 10000 rpm for 3 minutes, and the supernatant was recovered to obtain a dispersion liquid b in which luminescent particles b were dispersed in a colloidal state. When X-ray powder diffraction was performed on the luminescent particles b, it was found that the semiconductor nanocrystal constituting the luminescent particles b was CsPbBr3 having a perovskite crystal structure. Also, the elemental distribution of the luminescent particles b was evaluated by STEM-EDS, and it was confirmed that Si was contained in the surface layer of the luminescent particles b. Further, when the dispersion liquid b was depressurized at 25 °C to evaporate the solvent to obtain a powder of luminescent particles a and solid-state NMR of 29Si nuclei was measured, a peak indicating Si(T) was observed, but a peak indicating Si(Q) was not observed. Furthermore, for the luminescent particles b, when the weight loss rate in the range of 100 to 470 °C was calculated by thermogravimetric differential thermal analysis (TG-DTA; heating rate 10 °C / min, under nitrogen atmosphere) measurement, it was 42.0%. This Si is considered to be derived from the siloxane bond generated by the hydrolysis of APTES. That is, in the dispersion liquid b, luminescent particles b having CsPbBr3 with a perovskite crystal structure as the core and a surface layer containing a siloxane bond derived from a silane compound of T unit are dispersed in a colloidal state. When the luminescent particles b were analyzed by a particle size distribution measuring device (NanoTrac Wave II), the average particle size was 15 nm.

[0208] (Production Example of Luminescent Particles of the Present Invention) (Example 1) [Preparation of Dispersion Liquid 1 Containing Luminescent Particles 1] 0.8 g of Polymer 1 obtained by the method of Production Example 1 was dissolved in 5 mL of toluene with stirring at 60°C, and then 5 mL of Dispersion Liquid a obtained by the method of Production Example 4 was added, and the mixture was stirred at 60°C for 15 minutes. After returning to room temperature, 0.25 mL of 3-bromopropyltrimethoxysilane (BrPTMS; manufactured by Tokyo Chemical Industry Co., Ltd.), a halogenated alkoxysilane compound of the T unit, was added, and the mixture was stirred at room temperature for 12 hours. Thereafter, 0.5 mL of a silane compound of the Q unit represented by the following formula (B1-1) (methyl silicate-51, manufactured by Colcoat Co., Ltd., the average value of m in the formula (B1-1) is 4; hereinafter referred to as "MS-51"), and 0.025 mL of a 10% by mass aqueous solution of formamidine bromide (FABr) were added, and the mixture was stirred at room temperature for 2 hours.

[0209] [Chemical Formula]

[0210] The obtained mixed solution was centrifuged under the conditions of 9000 rpm for 5 minutes, and then the supernatant was recovered to obtain Dispersion Liquid 1 containing Luminescent Particles 1 having a surface layer containing a siloxane bond on the surface of Luminescent Particles a. Regarding Luminescent Particles 1, the elemental distribution was evaluated by energy-dispersive X-ray analysis (STEM-EDS) using a scanning transmission electron microscope, and it was confirmed that Si was contained in the surface layer of Luminescent Particles 1. When the thickness of the surface layer was measured, it was about 4 nm. The dispersion liquid 1 was decompressed at 25 °C to evaporate the solvent, obtaining a powder of the luminescent particles 1. When measuring the solid NMR of the 29Si nucleus, Si(T) / Si(Q) was 0.43. Also, for the luminescent particles 1, when calculating the weight loss rate in the range of 100 to 470 °C by thermogravimetric differential thermal analysis (TG-DTA; heating rate 10 °C / min, under nitrogen atmosphere), it was 65.4%. By thermodecomposition gas chromatography mass spectrometry (TD / Py-GC / MS) measurement, Polymer 1 was identified as a component. When analyzing the luminescent particles 1 with a particle size distribution measuring device (NanoTrac Wave II), the average particle size was 33 nm.

[0211] (Example 2) In Example 1, except that 3-bromopropyltrimethoxysilane was changed to 0.10 mL, the same operations as in Example 1 were performed to obtain a dispersion liquid 2 containing luminescent particles 2. When analyzing the luminescent particles 2 with a particle size distribution measuring device (NanoTrac Wave II), the average particle size was 31 nm.

[0212] (Example 3) In Example 1, except that 3-bromopropyltrimethoxysilane was changed to 0.50 mL, the same operations as in Example 1 were performed to obtain a dispersion liquid 3 containing luminescent particles 3. When analyzing the luminescent particles 3 with a particle size distribution measuring device (NanoTrac Wave II), the average particle size was 36 nm.

[0213] (Example 4) In Example 1, except that 3-bromopropyltrimethoxysilane was changed to 1.0 mL, the same operations as in Example 1 were performed to obtain a dispersion liquid 4 containing luminescent particles 4. When analyzing the luminescent particles 3 with a particle size distribution measuring device (NanoTrac Wave II), the average particle size was 40 nm.

[0214] (Example 5) In Example 1, a dispersion liquid 5 containing luminescent particles 5 was obtained by performing the same operations as in Example 1, except that Polymer 2 was added instead of Polymer 1. When the luminescent particles 5 were analyzed with a particle size distribution measuring device (NanoTrac Wave II), the average particle size thereof was 35 nm.

[0215] (Example 6) In Example 1, a dispersion liquid 6 containing luminescent particles 6 was obtained by performing the same operations as in Example 1, except that 0.025 mL of a 10 mass% aqueous solution of formamidine bromide was not added. When the luminescent particles 6 were analyzed with a particle size distribution measuring device (NanoTrac Wave II), the average particle size thereof was 33 nm.

[0216] (Example 7) In Example 1, a dispersion liquid 7 containing luminescent particles 7 was obtained by performing the same operations as in Example 1, except that the dispersion liquid a was changed to the dispersion liquid b obtained by the method of Production Example 5, and the 10 mass% aqueous solution of formamidine bromide was changed to the 10 mass% aqueous solution of cesium bromide. When the luminescent particles 7 were analyzed with a particle size distribution measuring device (NanoTrac Wave II), the average particle size thereof was 32 nm.

[0217] (Comparative Example 1) 5 mL of toluene was added to 5 mL of the dispersion liquid a obtained by the method of Production Example 5, and the mixture was stirred and mixed at room temperature for 15 minutes. The obtained mixture was centrifuged under the conditions of 9000 rpm for 5 minutes, and then the supernatant was recovered to obtain a dispersion liquid C1 containing luminescent particles a.

[0218] (Comparative Example 2) In Comparative Example 2, a dispersion liquid C2 containing luminescent particles b was obtained by performing the same operations as in Comparative Example 1, except that the dispersion liquid b obtained in Production Example 6 was used instead of the dispersion liquid a.

[0219] (Comparative Example 3) In Example 1, a dispersion liquid C3 containing luminescent particles c was obtained by performing the same operations as in Example 1, except that Polymer 3 was added instead of Polymer 1.

[0220] (Comparative Example 4) In Example 1, a dispersion liquid C4 containing luminescent particles d was obtained by performing the same operations as in Example 1, except that 10% by mass aqueous solutions of Polymer 1, 3-bromotrimethoxysilane, and formamidine bromide were not added.

[0221] (Comparative Example 5) In Example 1, a dispersion liquid C5 containing luminescent particles e was obtained by performing the same operations as in Example 1, except that 10% by mass aqueous solutions of 3-bromotrimethoxysilane and formamidine bromide were not added.

[0222] (Comparative Example 6) In Example 1, a dispersion liquid C6 containing luminescent particles f was obtained by performing the same operations as in Example 1, except that 10% by mass aqueous solutions of 3-bromotrimethoxysilane and formamidine bromide were not added, and 0.25 mL of bromotrimethylsilane (BrTMS; manufactured by Tokyo Chemical Industry Co., Ltd.) was added.

[0223] For each of the obtained dispersion liquids 1 to 7 and C1 to C6, using an absolute PL quantum yield measurement device (manufactured by Hamamatsu Photonics K.K., "Quantaurus-QY"), the absolute quantum yield (PLQY), peak wavelength (λmax) of the emission spectrum, and full width at half maximum (FWHM) of the emission spectrum of the dispersion liquid immediately after preparation were measured. The results are shown in Table 1.

[0224] [Table 1]

[0225] (Production and Evaluation of Ink Composition) (Example 8) [Preparation Example of Ink Composition] 4 mL of hexane and 2 mL of the dispersion 1 obtained in Example 1 were added to a glass vial equipped with a stir bar, and the mixture was stirred. The resulting suspension was centrifuged at 4000 rpm for 1 minute. By removing the supernatant, a solid X1 containing luminescent particles 1 was obtained. In a clean room where light with a wavelength of 500 nm or less was cut off, 6 parts by mass of phenoxyethyl acrylate (PhEA; “Light Acrylate POA” manufactured by Kyoeisha Chemical Co., Ltd.), 10 parts by mass of dimethyloltricyclodecane diacrylate (DCPA; “Light Acrylate DCP-A” manufactured by Kyoeisha Chemical Co., Ltd.), 3.1 parts by mass of trimethylolpropane triacrylate (TMPTA; “MIRAMER M-300” manufactured by MIWON Specialty Chemical Co., Ltd.) and 0.2 parts by mass of diphenyl(2,4,6-trimethoxybenzoyl)phosphine oxide (TPO; “Omnirad TPO” manufactured by IGM Resin Co., Ltd.) were added to a glass vial equipped with a stir bar, and the mixture was stirred and dissolved at room temperature. Subsequently, 0.2 parts by mass of the above solid X1 was added and stirred and dissolved at room temperature. Further, 0.5 parts by mass of the light-scattering particle dispersion obtained in Production Example 4 was added and stirred to homogenize. Thereafter, an ink composition 1 containing luminescent particles 1 was prepared by filtering through a membrane filter (pore size: 0.50 μm).

[0226] (Examples 9 to 14, Comparative Examples 7 to 12) In Example 8, ink compositions 2 to 7 and ink compositions C1 to C6 were prepared in the same manner as in Example 8, except that the dispersions C1 to C6 obtained in Examples 2 to 7 and Comparative Examples 1 to 6 were used instead of the dispersion 1 obtained in Example 1.

[0227] (Storage stability of ink composition) Regarding the obtained ink compositions 1 to 7 and C1 to C6, they were placed in glass vials and stored at room temperature for 30 days under light shielding, and the dispersion stability was visually evaluated according to the following criteria. The results are shown in Table 2. <Evaluation criteria for storage stability of ink composition> A: Transparent state, no precipitate was confirmed B: Transparent state, a slight precipitate was confirmed C: Opaque state, with a large amount of precipitate observed

[0228] As shown in Table 2, the ink compositions of Examples 8 to 14 are excellent in dispersion stability as compared with Comparative Examples 7 to 12.

[0229] (Manufacture and Evaluation of Light Conversion Layer) (Manufacture of Light Conversion Layer) Each of the ink compositions obtained in Examples 8 to 14 and Comparative Examples 7 to 12 was dropped onto a glass substrate Eagle XG (manufactured by Corning), and another glass substrate Eagle XG was placed on top. After forming a coating film before curing of each ink composition, the following luminescence property evaluation was performed. Then, in a nitrogen atmosphere, UV light with a main wavelength of 395 nm was irradiated so that the integrated light amount became 10 J / cm 2 to manufacture a 100-μm-thick light conversion layer containing luminescent particles and composed of a cured product of each ink composition.

[0230] (Luminescence Property Evaluation) Regarding each coating film (ink composition) before curing and each light conversion layer, the internal quantum efficiency (IQE) was measured at an excitation wavelength of 450 nm using an absolute PL quantum yield measurement device (manufactured by Hamamatsu Photonics K.K., "Quantaurus-QY (C11347-01)"), and the IQE retention rate (%) when forming each light conversion layer from each coating film before curing was calculated by the following formula. IQE retention rate (%) before and after curing = 100 × (IQE of light conversion layer / IQE of coating film before curing)

[0231] (Evaluation of Light Resistance) Regarding each light conversion layer, using a light resistance tester (manufactured by CCS), blue light with a peak wavelength of the emission spectrum of 450 nm was irradiated at a stage temperature of 50°C and 100 mW / cm 2 for 250 hours in air. The IQE of the light conversion layer after light irradiation was measured at an excitation wavelength of 450 nm using an absolute PL quantum yield measurement device (manufactured by Hamamatsu Photonics K.K., "Quantaurus-QY (C11347-01)"), and the IQE retention rate was calculated from the following formula (1) and evaluated according to the following criteria. IQE retention rate (%) in the light resistance test = 100 × (IQE of the light conversion layer after light irradiation / IQE of the light conversion layer before light irradiation) ··· Equation (1) <Evaluation criteria for light resistance> ◎: Retention rate is 97% or more ○: Retention rate is less than 97% and 95% or more △: Retention rate is less than 95% and 90% or less ×: Retention rate is less than 90%

[0232] (Evaluation of damp heat resistance) For each light conversion layer, it was stored for 500 hours under the conditions of 60 °C and 90% RH using a thermo-hygrostat test chamber. The IQE retention rate before and after the test was calculated by the following Equation (2) and evaluated according to the following criteria. IQE retention rate (%) in the damp heat resistance test = 100 × (IQE of the light conversion layer after 500-hour test / IQE of the light conversion layer before the test) ··· Equation (2) <Evaluation criteria for damp heat resistance> ◎: Retention rate is 97% or more ○: Retention rate is less than 97% and 95% or more △: Retention rate is less than 95% and 90% or less ×: Retention rate is less than 90%

[0233] The above evaluation results are summarized and shown in Table 2.

[0234]

Table 2

[0235] The luminescent particles 1 to 7 contained in the dispersions of Examples 1 to 7 all have, as the surface layer, a first shell layer containing a hydrolytic condensate of APTES, which is a silane compound of the T unit, and also have a second shell layer containing a hydrolytic condensate of BrPTMS, which is a halogenated alkoxysilane compound of the T unit, and MS-51, which is a silane compound of the Q unit. That is, the luminescent particles 1 to 7 have a surface layer containing a hydrolytic condensate of silane compounds of the T unit and the Q unit on the surface of a semiconductor nanocrystal composed of a metal halide, and are luminescent particles containing 50 mass% to 70 mass% of an organic component calculated by thermogravimetric analysis. On the one hand, although the luminescent particles a to b contained in the dispersions of Comparative Examples 1 to 2 have a surface layer containing a hydrolysis condensate of a silane compound of the T unit on the surface of the semiconductor nanocrystal composed of metal halide, they do not contain a hydrolysis condensate of a silane compound of the Q unit and are luminescent particles containing less than 50% by mass of the organic component calculated by thermogravimetric analysis. Further, although the luminescent particles c to f contained in the dispersions of Comparative Examples 3 to 6 have a surface layer containing a hydrolysis condensate of a silane compound of the T unit and the Q unit on the surface of the semiconductor nanocrystal composed of metal halide, they are luminescent particles containing less than 50% by mass or 70% by mass or more of the organic component calculated by thermogravimetric analysis.

[0236] As shown in Table 2 and as shown in Examples 8 to 14, the ink composition containing the luminescent particles of the present invention has a higher IQE retention rate (%) before and after curing of the coating film as compared with the ink composition containing the luminescent particles shown in Comparative Examples 7 to 12. From this, it can be seen that the luminescent particles 1 to 7 are less likely to be deteriorated by the radicals generated by the photoinitiator during curing of the coating film as compared with the luminescent particles a to f. Further, the light conversion layer formed from the ink composition containing the luminescent particles of the present invention has a high IQE retention rate (%) when exposed to light for 250 hours. From this, it can be seen that the luminescent particles 1 to 7 have high stability against light as compared with the luminescent particles a to f. Furthermore, the IQE retention rate is high after storage at 60 ° C. and 90% RH for 500 hours. From this, it can be seen that the luminescent particles 1 to 7 have high stability against water and heat as compared with the luminescent particles a to f.

[0237] From the above results, when the light conversion layer containing the luminescent particles of the present invention is used to form the wavelength conversion film or the color filter pixel portion of the light emitting element, it can be expected that excellent light emitting characteristics and stability can be obtained.

Description of symbols

[0238] 10… Pixel part, 10a… First pixel part, 10b… Second pixel part, 10c… Third pixel part, 11a… First light-emitting particle, 11b… Second light-emitting particle, 12a… First light-scattering particle, 12b… Second light-scattering particle, 12c… Third light-scattering particle, 20… Light-shielding part, 30… Light conversion layer, 40… Substrate, 50… Laminated structure, 51… First substrate, 52… Second substrate, 53… Encapsulation layer, 54… Light conversion film, 541… Light-scattering particles, 542… Light-emitting particles, 100… Color filter.

Claims

1. A luminescent particle having a surface layer on semiconductor nanocrystal particles composed of metal halide, wherein the surface layer contains a hydrolysis condensate of a silane compound of the T unit and a hydrolysis condensate of a silane compound of the Q unit, the luminescent particle contains 50% by mass or more and 70% by mass or less of an organic component calculated by thermogravimetric differential thermal analysis, and is characterized by the luminescent particle.

2. The luminescent particle according to claim 1, wherein the surface layer contains a hydrolysis condensate of a silane compound of the T unit represented by the following general formula (T1) and a hydrolysis condensate of a silane compound of the Q unit represented by the following general formula (Q1), and further contains a hydrolysis condensate of a halogenated alkoxysilane compound of the T unit. 【Chemical Formula 1】 (In the formula, R Ｔ１ , R Ｔ２ and R Ｔ３ each independently represents an alkyl group having 1 to 4 carbon atoms, X Ｔ１ represents an alkyl group having 1 to 10 carbon atoms and a single bond, and the alkyl group may be linear or branched. Any hydrogen atom in the alkyl group may be substituted with a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom. One -CH ２ - or two or more non - adjacent -CH ２ - may each independently be substituted with -NH-, -O-, -C(=O)-, -C=N-, -N=C- or a 1,4 - phenylene group. R ４ represents a monovalent group having at least one selected from the group consisting of a hydroxy group, a carboxyl group, an amino group, a mercapto group, an acrylic group, a methacrylic group, an acryloyl group, a methacryloyl group, an isocyanate group, and a cyclic ether group.) [Chemical 2] (wherein, R Ｑ１ and R Ｑ２ each independently represents an alkyl group having 1 to 4 carbon atoms, R Ｑ３ and R Ｑ４ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and m represents an integer of 1 or more and 10 or less).

3. The luminescent particle according to claim 1 or 2, wherein the surface layer further contains a polymer having a base.

4. The luminescent particle according to claim 1 or 2, wherein the halogenated alkoxysilane compound is at least one selected from the group consisting of 3-bromopropyltrimethoxysilane, 3-bromopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3-iodopropyltrimethoxysilane, and 3-iodopropyltriethoxysilane.

5. An ink composition containing the luminescent particle according to claim 1 or 2, a photopolymerizable compound, and a photoinitiator.

6. A light conversion layer containing a polymer of the ink composition according to claim 5.

7. A wavelength conversion film provided with the light conversion layer according to claim 6.

8. A color filter provided with the light conversion layer according to claim 6.

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