Light emitting particle, method for producing light emitting particle, ink composition, phototransformation layer, color filter, and wavelength conversion film

Abstract

To provide a light emitting particle excellent in stability to water, light, and heat and including a nanocrystal and a method for producing the same, an ink composition including the light emitting particle and a phototransformation layer including a cured product of the ink composition, and a color filter provided with the phototransformation layer and a wavelength conversion film.SOLUTION: A light emitting particle comprises a surface layer including a structure having a siloxane linkage on a surface of a semiconductor nanocrystal composed of a metal halide, where the surface layer includes a salt having a univalent cation, the semiconductor nanocrystal is composed of a compound represented by a general formula AaMbXc, the A represents a specific cation, the M represents a specific metal ion, the X represents one or more halide ions selected from the group consisting of F, Cl, Br, and I, a represents a positive number of 1 to 7, b represents a positive number of 1 to 4, and c represents a positive number of 1 to 16.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to luminescent particles, a method for producing the luminescent particles, an ink composition containing the luminescent particles, a light conversion layer including a cured product of the ink composition, a color filter, and a wavelength conversion film.

Background Art

[0002] As a luminescent material that satisfies the international standard BT.2020 required for next-generation display elements, semiconductive nanocrystals have attracted attention. For example, a light conversion sheet that extracts red light or green light using luminescent nanocrystals such as quantum dots, quantum rods, and other inorganic phosphor particles, a light conversion layer such as a color filter pixel portion, and a display device or lighting device that uses luminescent nanocrystals for a backlight have been proposed. Luminescent nanocrystals emit fluorescence or phosphorescence and have the characteristic of a narrow half-value width of the emission spectrum. In currently mainstream core-shell type quantum dots, CdSe etc. were initially used, but recently InP etc. have been used in order to avoid the harmfulness of Cd. However, the stability as particles is low, and studies for improving stabilization are being actively carried out. Also, since the emission wavelength of core-shell type quantum dots is determined by their particle size, in order to obtain emission with a narrow half-value width, it is necessary to precisely control the degree of dispersion of the particle diameter, and there are many problems in its production.

[0003] On the other hand, in recent years, quantum dots having a perovskite crystal structure have been discovered and attracted attention. For example, a nanocrystal which is a metal halide composed of cesium, lead, and a halogen and has a perovskite crystal structure represented by the general formula CsPbX 3 (X represents an anion of a halogen atom.) has the advantage that the emission wavelength can be controlled by adjusting the type and the abundance ratio of the halogen atoms, and it is disclosed in Non-Patent Document 1 that it has excellent physical properties as a luminescent material. Also, the control of the particle size is easier than that of InP quantum dots etc., and it is advantageous in terms of productivity. Patent Document 1 discloses a luminescent crystal having a perovskite crystal structure, a solid polymer-containing composition derived from an acrylate polymer, and a luminescent component. Generally, luminescent nanocrystals having a perovskite crystal structure are synthesized by a hot injection method or a ligand-assisted reprecipitation (LARP) method. Since luminescent nanocrystals having a perovskite crystal structure are liable to deteriorate by light or heat in the presence of moisture or oxygen, improvement in stability against moisture, light, and heat is required. From such a viewpoint, a method of forming a layer (silica layer) containing a structure having a siloxane bond on the surface of the nanocrystals with a silane compound has been studied. For example, Non-Patent Document 2 discloses a method of adding an inorganic salt together with an organic ligand during the formation of the silica layer to passivate the surface.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Non-Patent Documents

[0005]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] When forming a silica layer on the surface of nanocrystals with a silane compound, there is a problem that the nanocrystals having a perovskite crystal structure are liable to deteriorate due to water molecules involved in the hydrolysis of the silane compound and the alcohol generated during hydrolysis. Further, in the method of Non-Patent Document 2, it is difficult to suppress defects due to the desorption of the A site of the nanocrystals having a perovskite crystal structure, and improvement in stability is still required.

[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 a method for producing such luminescent particles, an ink composition containing such luminescent particles, a light conversion layer containing a cured product of the ink composition, and a color filter and a wavelength conversion film provided with the light conversion layer.

Means for Solving the Problems

[0008] The present invention has the following aspects. [1] A surface layer containing a structure having a siloxane bond is provided on the surface of a semiconductor nanocrystal composed of a metal halide, and the surface layer contains a salt having a monovalent cation. The semiconductor nanocrystal has the general formula A a M b X c and is composed of a compound represented by wherein A represents one or more cations selected from the group consisting of Cs, Rb, methylammonium, formamidinium, ammonium, 2-phenylethylammonium, pyrrolidinium, piperidinium, 1-butyl-1-methylpiperidinium, tetramethylammonium, tetraethylammonium, benzyltrimethylammonium, benzyltriethylammonium, guanidinium, imidazolium, pyridinium, and protonated thiourea; M represents 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; X represents one or more halide ions selected from the group consisting of F, Cl, Br, and I; a represents a positive number from 1 to 7, b represents a positive number from 1 to 4, and c represents a positive number from 1 to 16, and the luminescent particles. [2] The luminescent particles according to [1], wherein the semiconductor nanocrystal has a perovskite crystal structure. [3] The luminescent particles according to [1] or [2], wherein the salt having a monovalent cation contains a halogen ion. [4] The luminescent particles according to any one of [1] to [3], wherein the monovalent cation in the salt having the monovalent cation is an organic cation or a metal ion. [5] A surface layer containing a structure having a siloxane bond is provided on the surface of a semiconductor nanocrystal composed of a metal halide, and the surface layer contains a salt having a monovalent cation. The semiconductor nanocrystal has the general formula A a M b X c and is composed of a compound represented by wherein A represents one or more cations selected from the group consisting of Cs, Rb, methylammonium, formamidinium, ammonium, 2-phenylethylammonium, pyrrolidinium, piperidinium, 1-butyl-1-methylpiperidinium, tetramethylammonium, tetraethylammonium, benzyltrimethylammonium, benzyltriethylammonium, guanidinium, imidazolium, pyridinium, and protonated thiourea; M represents 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; X represents one or more halide ions selected from the group consisting of F, Cl, Br, and I; a represents a positive number from 1 to 7, b represents a positive number from 1 to 4, and c represents a positive number from 1 to 16. A method for producing luminescent particles, comprising: forming a semiconductor nanocrystal having a surface layer containing a siloxane bond on the surface of the semiconductor nanocrystal by forming a siloxane bond on the surface of the semiconductor nanocrystal while forming the semiconductor nanocrystal from a solution containing a raw material compound capable of synthesizing the semiconductor nanocrystal, a silane compound A having a bonding group and a hydrolyzable silyl group capable of bonding to the surface of the semiconductor nanocrystal, and a solvent, to obtain precursor particles having a surface layer containing a siloxane bond on the surface of the semiconductor nanocrystal; A step of obtaining a mixture by mixing the precursor particles, a polymer compound having a structural unit containing a basic group, and a silane compound B having a hydrolyzable silyl group and different from the silane compound A, and then adding an aqueous solution containing a salt containing a monovalent cation to the mixture to form a siloxane bond on the surface of the precursor particles, thereby obtaining luminescent particles provided with the surface layer containing the salt and the polymer compound on the surface of the precursor particles, and a method for producing luminescent particles. [6] An ink composition containing the luminescent particles according to any one of [1] to [4], a photopolymerizable compound, and a photoinitiator. [7] A light conversion layer containing a cured product of the ink composition according to [6]. [8] A color filter provided with the light conversion layer according to [7]. [9] A wavelength conversion film provided with the light conversion layer according to [7]. [Effect of the Invention]

[0009] According to the present invention, it is possible to provide luminescent particles containing nanocrystals, a method for producing the luminescent particles, an ink composition containing the luminescent particles, a light conversion layer containing a cured product of the ink composition, and a color filter and a wavelength conversion film provided with the light conversion layer, which are excellent in stability against water, light, and heat. [Brief Description of the Drawings]

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

[0011] 1. Luminescent Particles The luminescent particles of the present invention include a surface layer having a structure with siloxane bonds on the surface of a semiconductor nanocrystal composed of a metal halide, and the surface layer contains a salt having a monovalent cation. The semiconductor nanocrystal has the general formula A a M b X c and is composed of a compound represented by wherein A represents one or more cations selected from the group consisting of Cs, Rb, methylammonium, formamidinium, ammonium, 2-phenylethylammonium, pyrrolidinium, piperidinium, 1-butyl-1-methylpiperidinium, tetramethylammonium, tetraethylammonium, benzyltrimethylammonium, benzyltriethylammonium, guanidinium, imidazolium, pyridinium, and protonated thiourea; M represents 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; X represents one or more halide ions selected from the group consisting of F, Cl, Br, and I; a represents a positive number from 1 to 7, b represents a positive number from 1 to 4, and c represents a positive number from 1 to 16, and they are luminescent particles. As will be described later, the luminescent particles of the present invention can be suitably used as a wavelength conversion material for forming a light conversion layer used in display elements such as light-emitting diodes (LEDs).

[0012] The luminescent particles of the present invention contain a luminescent semiconductor nanocrystal and can emit light (fluorescence or phosphorescence) having a wavelength different from the absorbed wavelength by absorbing light of a predetermined wavelength. Here, the luminescence property preferably refers to the property of emitting light by excitation of electrons, and more preferably, when excited light is irradiated, the electrons contained in the nanocrystal are excited from the ground state to the excited state and emit light when returning to the ground state.

[0013] <Semiconductor nanocrystal composed 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.

[0014] 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. The general formula A a M b X c Specific examples of the compound represented by include AMX, A 4 MX, AMX 2 、AMX 3 、A 2 MX 3 、AM 2 X 3 、A 2 MX 4 、A 2 MX 5 、A 3 MX 5 、A 3 M 2 X 5 、A 3 MX 6 、A 4 MX 6 、AM 2 X 6 、A 2 MX 6 、A 4 M 2 X 6 、A 3 MX 8 、A 3 M 2 X 9 、A3 M 3 X 9 、A 2 M 2 X 10 、A 7 M 3 X 16 The compound represented by is preferred.

[0015] 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. M represents at least one metal cation. Specifically, one metal cation (M 1 ), two metal cations (M 1 α M 2 β ), three metal cations (M 1 α M 2 β M 3 γ ), four metal cations (M 1 α M 2 β M 3 γ M 4 δ) and the like can be mentioned. 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, and Zr can be mentioned. 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 can be mentioned. The emission wavelength (emission color) of the nanocrystal can be controlled by adjusting its particle size, the type and abundance ratio of the anions constituting the X site. Further, from the viewpoint of further improving the luminescence properties, the nanocrystal may be one doped with metal ions such as Bi, Mn, Ca, Eu, Sb, and Yb different from the metal cation used at the M site.

[0016] Among the nanocrystals represented by the general formula A a M b X c compounds having a perovskite crystal structure are particularly preferable as nanocrystals in that the emission wavelength (emission color) can be controlled by adjusting its particle size, the type and abundance ratio of the metal cations constituting the M site, and further, the type and abundance ratio of the anions constituting the X site. Since this adjustment operation can be easily performed, perovskite-type semiconductor nanocrystals are characterized by being easier to control the emission wavelength and having higher productivity compared to conventional core-shell-type semiconductor nanocrystals. Specifically, from the viewpoint of having excellent luminescence properties, AMX 3, A 3 MX 5 , A 3 MX 6 , A 4 MX 6 , A 2 MX 6 The compound represented by is preferred. From the viewpoints of luminescence characteristics and ease of synthesis, AMX 3 is more preferred. Preferred. 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, which are different from the metal cations used in the M site as described above.

[0017] Among the compounds having a perovskite crystal structure, from the viewpoints of ease of synthesis, good luminescence characteristics, and robustness of the crystal structure, A is one or more cations selected from the group consisting of Cs, Rb, methylammonium, formamidinium, ammonium, 2-phenylethylammonium, pyrrolidinium, piperidinium, 1-butyl-1-methylpiperidinium, tetramethylammonium, tetraethylammonium, benzyltrimethylammonium, benzyltriethylammonium, guanidinium, imidazolium, pyridinium, and protonated thiourea, and cations selected from Cs, Rb, methylammonium, and formamidinium are more preferred. M is one kind of metal cation (M 1 ), or two kinds of metal cations (M 1 α M 2 β (However, α and β each represent a real number from 0 to 1, and α + β = 1.)). From the viewpoints of ease of synthesis, good luminescence characteristics, and robustness of the crystal structure, it 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, still 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, and from the viewpoints of ease of synthesis, good luminescence characteristics, and robustness of the crystal structure, Cl - , Br - , I - A halide ion selected from the group consisting of is more preferable, and Br - , I - A halide ion selected from the group consisting of is even more preferable, and Br - is particularly preferable.

[0018] As specific compositions of the nanocrystals having a perovskite crystal structure, CsPbBr 3 , (CH 3 NH 3 )PbBr 3 , (CHN 2 H 4 )PbBr 3 , CsPbI 3 , (CH 3 NH 3 )PbI 3 , (CHN 2 H 4 )PbI 3 , CsPb(Br / I) 3 , (CH 3 NH 3 )Pb(Br / I) 3 , (CHN 2 H 4 )Pb(Br / I) 3 etc., nanocrystals using Pb as M are preferable because they are excellent in light intensity and quantum efficiency. Also, CsSnBr 3 , CsSnCl 3 , CsSnBr 1.5 Cl 1.5 , Cs 3 Sb 2 Br 9 , (CH 3 NH 3 ) 3 Bi 2 Br 9 , (C 4 H 9 NH 3 ) 2 AgBiBr 6Nanocrystals using metal cations other than Pb as M such as etc. are preferable because they have low toxicity and little impact on the environment.

[0019] As the 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 measuring device.

[0020] 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.

[0021] The green light-emitting nanocrystals preferably have an emission peak in the 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 the 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.

[0022] The blue-light-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.

[0023] 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. By using nanocrystals of such a shape, luminescent particles reflecting the shape can be obtained, and the uniform dispersibility and fluidity when preparing an ink composition containing such luminescent particles can be further improved.

[0024] The average particle diameter (volume average diameter) of the nanocrystals is preferably 40 nm or less, more preferably 30 nm or less, further 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, further 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.

[0025] <Surface layer containing a structure having a siloxane bond> The luminescent particles of the present invention are provided with a surface layer (silica layer) containing a structure having a siloxane bond on the surface of the nanocrystal, and the surface layer contains a salt having a monovalent cation. In other words, the luminescent particles of the present invention have a nanocrystal as a core and, as a shell, a surface layer containing a siloxane bond on at least a part of its surface, and such a surface layer contains a salt having a monovalent cation. The surface layer may have one layer or a plurality of layers as a layer having a structure having a siloxane bond. From the viewpoint of improving the stability of the nanocrystal against moisture and oxygen, light resistance, etc., and improving the light resistance and long-term storage stability, etc. of the luminescent particles of the present invention, it is more preferable that the luminescent particles of the present invention have a plurality of layers of structures having siloxane bonds. When the surface layer has a plurality of layers as a layer having a structure having a siloxane bond, it is sufficient that one or more layers contain a salt having a monovalent cation, and all layers may contain a salt having a monovalent cation.

[0026] Hereinafter, the configuration of luminescent particles having a surface layer containing a structure having a siloxane bond resulting from a silane compound A (hereinafter simply referred to as "silane compound A") having a bonding group capable of bonding to the surface of the semiconductor nanocrystal and a hydrolyzable silyl group on the surface of the semiconductor nanocrystal, and a structure having a siloxane bond resulting from a silane compound B (hereinafter simply referred to as "silane compound B") having a hydrolyzable silyl group and different from silane compound A, and the surface layer containing a salt having a monovalent cation will be described. In the surface layer, in order from the side closer to the nanocrystal, the structure having a siloxane bond resulting from silane compound A is referred to as the "first shell layer", and the structure having a siloxane bond resulting from silane compound B is referred to as the "second shell layer". In the following description, the second shell layer contains a salt having a monovalent cation.

[0027] [First shell layer] In the first shell layer, the silane compound A that forms a structure having a siloxane bond has a bonding group capable of bonding to the surface of the nanocrystal and a hydrolyzable silyl group. In other words, the silane compound A has a reactive group capable of coordinating to the surface of the nanocrystal and forming a siloxane bond between molecules. The first shell layer preferably further contains, in addition to the silane compound A, a compound having a bonding group that binds to a cation or an anion contained in the nanocrystal. Such a compound will be described later.

[0028] As the hydrolyzable silyl group of the silane compound A, from the viewpoint of easily forming a siloxane bond, a silanol group, an alkoxysilyl group having 1 to 6 carbon atoms, etc. are preferable, and a silanol group, an alkoxysilyl group having 1 to 2 carbon atoms is more preferable. Examples of the bonding group of the silane compound A include 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 phosphoric acid group, a phosphonic acid group, a phosphinic acid group, a sulfonic acid group, a boronic acid group, and salts thereof. Among them, at least one of a carboxyl group, a mercapto group, and an amino group is preferable. Since these bonding groups have a higher affinity for the cations or anions contained in the nanocrystal than the hydrolyzable silyl group, the silane compound A 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 compound A, the first shell layer can be formed more easily and surely. As the silane compound A, a carboxyl group-containing silane compound, an amino group-containing silane compound, and a mercapto group-containing silane compound are preferable. These may be used alone or in combination of two or more.

[0029] Examples of the carboxyl group-containing silane compound include 3-(trimethoxysilyl)propionic acid, 3-(triethoxysilyl)propionic acid, 2-carboxyethylphenylbis(2-methoxyethoxy)silane, N-[3-(trimethoxysilyl)propyl]-N'-carboxymethylethylenediamine, N-[3-(trimethoxysilyl)propyl]phthalamide, N-[3-(trimethoxysilyl)propyl]ethylenediamine-N,N',N'-triacetic acid, 2-(2-oxo-2-((3-triethoxysilyl)propyl)amino)ethyl)-5-(ethoxysilyl)valeric acid, (6-triethoxysilyl)-3-[[[3-(triethoxysilyl)propyl]amino]carbonyl]hexanoic acid, and the like.

[0030] Examples of the amino group-containing silane compound include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldipropoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiisopropoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltripropoxysilane, N-(2-aminoethyl)-3-aminopropyltriisopropoxysilane, N-(2-aminoethyl)-3-aminoisobutyldimethylmethoxysilane, N-(2-aminoethyl)-3-aminoisobutylmethyldimethoxysilane, N-(2-aminoethyl)-11-aminoundecyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylsilanetriol, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N,N-bis[3-(trimethoxysilyl)propyl]ethylenediamine, (aminoethylaminoethyl)phenyltrimethoxysilane, (aminoethylaminoethyl)phenyltriethoxysilane, (aminoethylaminoethyl)phenyltripropoxysilane, (aminoethylaminoethyl)phenyltriisopropoxysilane, (aminoethylaminomethyl)phenyltrimethoxysilane, (aminoethylaminomethyl)phenyltriethoxysilane, (aminoethylaminomethyl)phenyltripropoxysilane, (aminoethylaminomethyl)phenyltriisopropoxysilane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropylmethyldimethoxysilane, N-β-(N-vinylbenzylaminoethyl)-N-γ-(N-vinylbenzyl)-γ-aminopropyltrimethoxysilane, N-β-(N-di(vinylbenzyl)aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(N-di(vinylbenzyl)aminoethyl)-N-γ-(N-vinylbenzyl)-γ-aminopropyltrimethoxysilane, methylbenzylaminoethylaminopropyltrimethoxysilane, dimethylbenzylaminoethylaminopropyltrimethoxysilane, benzylaminoethylaminopropyltrimethoxysilane, benzylaminoethylaminopropyltriethoxysilane, 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 can be mentioned.,

[0031] Examples of the mercapto group-containing silane compound include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 2-mercaptoethylmethyldimethoxysilane, 2-mercaptoethylmethyldiethoxysilane, 3-[ethoxybis(3,6,9,12,15-pentaoxaoctacosan-1-yloxy)silyl]-1-propanethiol and the like.

[0032] Examples of the bonding group that binds to the cation or anion contained in the nanocrystal include 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 phosphoric acid group, a phosphonic acid group, a phosphinic acid group, a sulfonic acid group, a boronic acid group, and salts thereof. Among them, it is preferably at least one of a carboxyl group, an amino group, a mercapto group, a sulfonic acid group, a phosphonic acid group, and salts thereof.

[0033] Compounds having a binding group that binds to a cation or anion contained in the nanocrystal, which are preferably further contained in the first shell layer, act as ligands that coordinate on the surface of the nanocrystal to enhance stability. Specifically, carboxyl group-containing compounds, amino group-containing compounds, mercapto group-containing compounds, sulfonic acid group-containing compounds, phosphonic acid group-containing compounds, and salts thereof are preferred. These may be used alone or in combination of two or more. From the viewpoint of improving the stability of the luminescent particles of the present invention, it is preferable to use together one or more of a carboxyl group-containing compound, an amino group-containing compound, a sulfonic acid group-containing compound, a phosphonic acid group-containing compound, and salts thereof, which are different from the silane compound A, and one or more of the silane compound A as ligands. By adding a ligand to at least one of the first solution or the second solution containing the raw material compound of the nanocrystal, which will be described later, nanocrystals having a ligand coordinated on the surface can be produced. The ligand can be coexisted during the synthesis of the nanocrystal or replaced with a ligand different from the ligand coexisted during the synthesis of the nanocrystal after the nanocrystal is formed.

[0034] Examples of the carboxyl group-containing compound include linear or branched aliphatic carboxylic acids having 1 to 30 carbon atoms, such as 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, heptacosanic acid, lauric acid, myristic acid, melissic acid, octacosanoic acid, nonadecanoic acid, nonacosanoic acid, n-octanoic acid, palmitic acid, pentadecanoic acid, propionic acid, pentacosanic acid, nonanoic acid, stearic acid, lignoceric acid, tricosanoic acid, tridecanoic acid, undecanoic acid, valeric acid, etc.

[0035] Examples of the amino group-containing compounds include linear or branched aliphatic amines having 1 to 30 carbon atoms, such as 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, octylamine, 1-aminodecane, nonylamine, 1-aminoundecane, dodecylamine, 1-aminopentadecane, 1-aminotridecane, hexadecylamine, and tetradecylamine.

[0036] Examples of the mercapto group-containing compounds include n-dodecyl mercaptan, tert-dodecyl mercaptan, 1-dodecanethiol, n-octyl mercaptan, and 1-octadecanethiol.

[0037] Examples of the sulfonic acid group-containing compounds or their salts include dodecylbenzenesulfonic acid, sodium 4-n-octylbenzenesulfonate, sodium 4-dodecylbenzene-1-sulfonate, sodium 4-undecylbenzenesulfonate, sodium 4-tetradecylbenzene-1-sulfonate, sodium 4-tridecylbenzene-1-sulfonate, sodium 1-decanesulfonate, sodium 1-dodecanesulfonate, and sodium lauryl sulfate. Examples of the phosphonic acid group-containing compounds or their salts include dodecylphosphonic acid.

[0038] Among the above-described compounds, in the present invention, as the ligand used in combination with the silane compound A, oleic acid, octanoic acid, lauric acid, dodecylbenzenesulfonic acid, dodecylphosphonic acid, oleylamine, octylamine, and trioctylphosphine are preferable, and oleic acid, lauric acid, oleylamine, dodecylbenzenesulfonic acid, and dodecylphosphonic acid are more preferable.

[0039] In particular, the first shell layer is preferably obtained by coordinating, as ligands, for example, oleic acid and 3-aminopropyltriethoxysilane on the surface of the nanocrystal, and further condensing the alkoxysilyl groups of 3-aminopropyltriethoxysilane to form siloxane bonds.

[0040] Also, the ligand used in combination with the silane compound A may be coordinated on the surface of the nanocrystal by adding it after forming the first shell layer on the surface of the nanocrystal.

[0041] The thickness of the first shell layer is preferably in the range of 0.5 to 50 nm, more preferably in the range of 1.0 to 30 nm. When the thickness of the first shell layer is within the above range, the stability of the luminescent particles of the present invention against moisture and heat can be sufficiently enhanced. The thickness of the first shell layer can be changed by adjusting the number of atoms (chain length) of the linking structure that links the bonding group and the reactive group of the ligand.

[0042] In the luminescent particles of the present invention, in addition to the above ligands, ammonium salts such as dodecyldimethylammonium bromide, phenethylammonium bromide, phenethylammonium iodide, methyltrioctylammonium bromide, tetraoctylammonium bromide, didecyldimethylammonium bromide, ditetradecyldimethylammonium bromide, etc. may be coordinated on the surface of the nanocrystal.

[0043] [Second shell layer] In order to uniformly form the second shell layer on the surface of the first shell layer, the second shell layer preferably includes a structure having a siloxane bond resulting from the silane compound B. The second shell layer contains a salt having a monovalent cation. The salt having a monovalent cation may be either an organic salt or an inorganic salt. Such a salt having a monovalent cation preferably contains a halogen ion. Examples of the halogen ion include F - , Cl - , Br - , I- Examples include these, and one or more of them may be included. When two or more kinds of halogen ions coexist, there is no particular limitation on the coexistence ratio. The halogen ion contained in the salt having a monovalent cation is represented by the general formula A a M b X c It may be the same as or different from the halide ion indicated by the X site that constitutes the above-described nanocrystal represented by, and it is more preferably the same. The monovalent cation constituting the salt having a monovalent cation is preferably an organic cation or a metal ion. 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. These salts having a monovalent cation may be used alone or in combination of two or more. The monovalent cation contained in the salt having a monovalent cation may be the same as or different from the monovalent cation indicated by the A site that constitutes the above-described nanocrystal represented by the general formula A a M b X c

[0044] From the viewpoint of uniformly coating the surface of the first shell layer with the second shell layer, a polymer compound having a structural unit containing a basic group (hereinafter also referred to as "polymer compound") is further allowed to coexist. Specifically, first, a reaction field is formed on the surface of the first shell layer by adsorbing the basic group of the polymer compound on the surface of the first shell layer. Then, silane compound B is mixed, and further a salt having a monovalent cation is mixed as an aqueous solution, so that silane compound B forms a siloxane bond on the surface of the first shell layer by condensation of the hydrolyzable silyl group it has in the reaction field, thereby forming a second shell layer containing a salt having a monovalent cation. By providing the second shell layer, the luminescent particles are excellent in stability against water, light, and heat, and as a result, have excellent luminescence characteristics. The polymer compound preferably has a first structural unit having a basic group and a second structural unit having excellent affinity for a dispersion medium and having no basic group. The dispersion medium means a compound capable of dispersing the luminescent particles of the present invention, and can be various organic solvents or photopolymerizable compounds.

[0045] Examples of the basic group of the first structural unit include a primary amino group, a secondary amino group, a tertiary amino group, a quaternary ammonium group, an imino group, a pyridyl group, a pyrimidine group, a piperazinyl group, a piperidyl group, an imidazolyl group, a pyrrolidinyl group, and an imidazolidinyl group. From the viewpoint of excellent adsorbability to the first shell layer, the basic group of the first structural unit is preferably a primary amino group, a secondary amino group, a tertiary amino group, a quaternary ammonium group, or a pyridyl group. Examples of the compound that provides the first structural unit include ethyleneimine, propyleneimine, 2-vinylpyridine, 4-vinylpyridine, 4-aminostyrene, 4-dimethylaminostyrene, 1-vinylimidazole, N-vinyl-2-pyrrolidone, dimethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, dimethylaminobutyl (meth)acrylate, diethylaminoethyl (meth)acrylate, diethylaminopropyl (meth)acrylate, dimethylaminopropyl acrylamide, diethylaminopropyl acrylamide, allylamine, and the like. The first structural unit may be composed of one of these compounds alone or two or more of them. In the present specification, the term “(meth)acrylate” is a general term for acrylate, methacrylate, and both of them.

[0046] Examples of the compound that provides the second structural unit 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-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 (meth)acrylate, 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 such as styrene, α-methylstyrene, 4-tert-butylstyrene, 2,5-dimethylstyrene, p-isobutylstyrene, etc. may be mentioned. Further, the second structural unit may have a structural unit having a polyester skeleton obtained by self-condensation of a hydroxycarboxylic acid such as 12-hydroxystearic acid or a lactone such as ε-caprolactone, β-propiolactone, γ-butyrolactone, δ-valerolactone, or mixed condensation of the hydroxycarboxylic acid and the lactone. It is preferable to use a compound having excellent compatibility with the photopolymerizable compound used in the ink composition described later as the second structural unit. Examples thereof include condensates of ethyleneimine and polyester, condensates of propyleneimine and polyester, and the like. The second structural unit may be composed of one kind of these compounds alone or two or more kinds thereof.

[0047] The polymer compound may be a block copolymer having a polymer block composed of a first structural unit and a polymer block composed of a second structural unit, may be a random polymer having the first structural unit and the second structural unit randomly, or may be a graft polymer having the first structural unit and the second structural unit. From the viewpoint of the adsorptivity to the surface of the first shell layer, it is preferable that the polymer compound is a block copolymer or a graft polymer.

[0048] The content of the first structural unit in the polymer compound is preferably 3 mol% or more, more preferably 4 mol% or more, based on all the structural units constituting the polymer compound. The content of the first structural unit is preferably 50 mol% or less, more preferably 30 mol% or less. The content of the second structural unit in the polymer compound is preferably 70 mol% or more, more preferably 75 mol% or more, based on all the structural units constituting the polymer compound. The content of the second structural unit is preferably 97 mol% or less, more preferably 96 mol% or less.

[0049] In addition to the first structural unit and the second structural unit, the polymer compound may further contain other structural units. When further containing other structural units, the total content of the first structural unit and the second structural unit in the polymer compound is preferably 70 mol% or more, more preferably 80 mol% or more, based on all the structural units constituting the polymer compound. Examples of the other structural units include structural units having acidic groups such as carboxyl group, sulfo group, sulfuric acid group, phosphonic acid group, phosphoric acid group, phosphinic acid group, and mercapto group. Examples of the compound that provides a structural unit having an acidic group include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl maleate, 2-(meth)acryloyloxyethyl phthalate, and other (meth)acrylates having a carboxy group; (meth)acrylates having a sulfonic acid group such as ethyl sulfonate (meth)acrylate; and (meth)acrylates having a phosphate group such as 2-(phosphonooxy)ethyl (meth)acrylate.

[0050] From the viewpoint of the dispersibility of the luminescent particles of the present invention, the weight average molecular weight (Mw) of the polymer compound is preferably 3,000 or more and 200,000 or less, more preferably 4,000 or more and 100,000 or less, and even more preferably 5,000 or more and 80,000 or less. Note that Mw is a value in terms of standard polystyrene measured under the gel permeation chromatography (GPC) measurement conditions described in the examples below.

[0051] As the silane compound B, a compound represented by the following formula (B1) (hereinafter also referred to as "silane compound B1") is preferable.

[0052]

Chemical formula

[0053] In the formula, R B1 and R B2 each independently represent an alkyl group, R B3 and R B4 each independently represent a hydrogen atom or an alkyl group, n represents 0 or 1, and m represents an integer of 1 or more. It is preferable that m is an integer of 10 or less. From the viewpoint of the robustness of the second shell layer, n preferably represents 1, more preferably m is an integer of 1 or more and 7 or less, and even more preferably n represents 1 and m is an integer of 1 or more and 4 or less.

[0054] Specific examples of the silane compound B1 include 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.)), etc. The silane compound B1 may be used alone or in combination of two or more.

[0055] In addition, the silane compound B1 may be used in combination with a compound represented by the following formula (B2) (hereinafter also referred to as "silane compound B2") and a compound represented by the following formula (B3) (hereinafter also referred to as "silane compound B3").

[0056]

Chemical formula

[0057] In the formula, R B21 、R B22and R B31 each independently represents an alkyl group, and R B23 , R B24 , R B32 , R B33 and R B34 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. Specific examples of the silane compound B2 and the silane compound B3 include dimethyldiethoxysilane, diphenyldimethoxysilane, methylethyldimethoxysilane, trimethylmethoxysilane, and the like. These can be used in combination with one or two or more of the silane compound B1.

[0058] One form of the luminescent particles of the present invention contains a semiconductor nanocrystal made of a metal halide and having luminescence properties, and a ligand coordinated to the surface of the semiconductor nanocrystal. The coordination of the ligand to the surface of the semiconductor nanocrystal can maintain the nanocrystal structure. As the ligand, a silane compound A is used, and further, for example, oleic acid, octanoic acid, lauric acid, oleylamine, octylamine, trioctylphosphine, etc. are used in combination. Thereby, a surface layer containing a siloxane bond, that is, a first shell layer, is formed on the surface of the semiconductor nanocrystal. The first shell layer can improve the stability of the semiconductor nanocrystal against water, light, and heat, and excellent luminescence characteristics can be obtained. Further, the presence of a surface layer, that is, a second shell layer, in which a silane compound B forms a siloxane bond by condensation on the surface of the first shell layer can further improve the stability of the semiconductor nanocrystal against water, light, and heat, and excellent luminescence characteristics can be obtained. Furthermore, the second shell layer contains a salt including a monovalent cation. In other words, the presence of a salt including a monovalent cation in the surface layer can suppress the generation of surface defects of the nanocrystals during the formation of the surface layer. And since a monovalent cation as the A-site component and a halogen ion as the X-site component constituting the nanocrystals can be present in the surface layer, the formation of defects due to the desorption of the A-site or halogen site from the nanocrystals by water, light, or heat can be suppressed, the stability of the luminescent particles against water, light, and heat can be improved, and excellent luminescent characteristics can be obtained.

[0059] 2. Method for producing luminescent particles The luminescent particles of the present invention can be produced, for example, by the following method. That is, a step of obtaining precursor particles having a surface layer containing a siloxane bond on the surface of semiconductor nanocrystals by forming a siloxane bond on the surface of the nanocrystals while forming the semiconductor nanocrystals from a solution containing a raw material compound capable of synthesizing the semiconductor nanocrystals, a silane compound A, and a solvent, a step of mixing the precursor particles, a polymer compound, and a silane compound B to obtain a mixture, and then adding an aqueous solution containing a salt including a monovalent cation to the mixture to form a siloxane bond on the surface of the precursor particles, thereby obtaining luminescent particles having a surface layer containing the salt and the polymer compound on the surface of the precursor particles.

[0060] For the step of obtaining precursor particles, for example, the hot injection method or the LARP method can be applied. Hereinafter, the step of obtaining precursor particles will be described. The step of obtaining precursor particles is the above-described A a M b X c It is preferable to prepare a plurality of solutions containing a raw material compound capable of synthesizing semiconductor nanocrystals composed of the compound represented by, the above-described ligand (a compound having a bonding group that binds to a cation or an anion contained in the nanocrystals), a silane compound A, and a solvent, mix these, and then condense the reactive groups (hydrolyzable silyl groups) of the silane compound A coordinated on the surface of the precipitated semiconductor nanocrystals. When mixing the solutions, heating may or may not be performed. Here, the raw material compounds are a compound containing cation A, a compound containing metal ion M, and a compound containing halide ion X. Examples of the compound containing cation A include hydroxides, acetates, carbonates, nitrates, sulfates of cation A; hydrates thereof; and the like. Examples of the compound containing metal ion M include oxides, hydroxides, halide salts, acetates, carbonates, nitrates, sulfates of the metal ion; hydrates thereof; and the like. Examples of the compound containing halide ion X include carboxylic acid halides, organosilicon halide compounds, hydrogen halides, and ammonium salts. Note that as the raw material compound, a metal halide salt containing metal ion M and containing halide X can be preferably used. Examples of the solvent include 1-octadecene, dioctyl ether, diphenyl ether, and the like.

[0061] When heating is performed when mixing the solutions, specifically, a first solution containing a compound containing cation A and a solvent, and a second solution containing a compound containing metal ion M, a compound containing halide ion X, and a solvent are each prepared. In the second solution, the aforementioned metal halide salt may be used instead of the compound containing metal ion M and the compound containing halide ion X. At this time, the above-mentioned ligand is added to one of the solutions, and silane compound A is added to the other solution to prepare each solution. The solution containing silane compound A may contain the above-mentioned ligand. By allowing the ligand or silane compound A to coexist in the preparation of each solution, when the first solution and the second solution are reacted, precursor particles containing semiconductor nanocrystals having the ligand or silane compound A on the surface can be obtained. Also, by allowing the ligand or silane compound A to coexist, when the first solution and the second solution are reacted, excessive crystal growth can be prevented, and precursor particles containing semiconductor nanocrystals within the target particle size range can be obtained. The amounts of the ligand and the silane compound A are in the range of 10% to 100% with respect to the volume amount of the solvent used for preparing each solution. However, when the first solution and the second solution are reacted, it is preferable from the viewpoint of easily obtaining precursor particles having a ligand coordinated on the surface of the semiconductor nanocrystal, and from the viewpoint of obtaining the effect of preventing excessive crystal growth by coexisting the ligand.

[0062] Next, a predetermined amount of the first solution is added to a predetermined amount of the second solution heated to 140 to 260 °C and reacted. After cooling to -20 to 30 °C, the mixture is further stirred at 10 to 30 °C under the atmosphere to precipitate precursor particles having a surface layer containing siloxane bonds on the surface of the semiconductor nanocrystal. The reaction time after mixing the first solution with the second solution is preferably within 5 minutes, more preferably in the range of 1 second to 60 seconds, and even more preferably in the range of 3 seconds to 10 seconds in order to obtain semiconductor nanocrystals having a particle diameter capable of suppressing excessive crystal growth and emitting light. Also, the cooling time after the reaction may vary depending on the set temperature when mixing the first solution with the second solution and the scale of the reaction. From the viewpoint of quickly precipitating the semiconductor nanocrystal, it is usually preferably in the range of 1 to 60 minutes. There is no particular limitation on the cooling means, and ice water, a water-ethylene glycol mixed refrigerant, a dry ice-acetone bath, etc. can be appropriately selected and used according to the target cooling temperature and the time until cooling. In addition, the preparation of each of the above-mentioned solutions, the mixing and reaction of the solutions, and the subsequent cooling operation may be performed under an air atmosphere or under an inert gas atmosphere such as nitrogen or argon. The precipitated precursor particles can be isolated by a conventional method such as centrifugation if necessary. Note that the mixing amounts of the first solution and the second solution can be appropriately adjusted according to the respective contents of the compound containing cation A, the compound containing metal ion M and the compound containing halide ion X (or the metal halide salt containing metal ion M and containing halide X), the ligand and the silane compound A contained in each solution, and the desired mixing ratio of cation A, metal ion M and halide ion X.

[0063] For example, for 40 mL of a solvent, 0.2 to 2 g of cesium carbonate as a compound containing cation A and 0.1 to 10 mL of oleic acid as a ligand are mixed, and after drying under reduced pressure at 90 to 150 °C for 10 to 180 minutes, it is heated to 100 to 200 °C to be dissolved, and a first solution, which is a cesium-oleic acid solution, can be prepared. On the other hand, for 5 mL of a solvent, 20 to 100 mg of lead(II) bromide as a metal halide containing metal ion M and halide ion X is added, and after drying under reduced pressure at 90 to 150 °C for 10 to 180 minutes, 0.1 to 2 mL of 3-aminopropyltriethoxysilane as silane compound A is added, and a second solution can be prepared. Next, after adding the first solution to the second solution heated to 140 to 260 °C and reacting, when it is cooled to -20 to 30 °C and stirred, semiconductor nanocrystals coordinated with 3-aminopropyltriethoxysilane and oleic acid are precipitated on the surface. This mixture is further stirred at 10 to 30 °C for 5 to 300 minutes in an atmosphere with a humidity of 5 to 60%, and then ethanol is added. While forming semiconductor nanocrystals, the ethoxysilyl groups of 3-aminopropyltriethoxysilane condense on the surface of the nanocrystals to form siloxane bonds, and a suspension containing precursor particles having a surface layer including a structure having siloxane bonds on the surface of the semiconductor nanocrystals is obtained. Here, the surface layer having siloxane bonds formed corresponds to the first shell layer described above. The obtained suspension can recover the precursor particles, for example, by centrifugation.

[0064] As described above, when obtaining the precursor particles, the first solution and the second solution may be mixed in a heated state, or may be mixed without heating. In that case, a method of precipitating semiconductor nanocrystals by dropping and mixing a solution containing a raw material compound of a metal halide and silane compound A having different ligands into a solution in which silane compound A is dissolved in a poor solvent for the semiconductor nanocrystals under the atmosphere can be mentioned. For example, for 10 mL of a solvent (good solvent) that dissolves semiconductor nanocrystals, such as dimethyl sulfoxide, N,N-dimethylformamide, N-methylformamide, etc., 5 to 25 mg of cesium bromide as a compound containing cation A, 10 to 50 mg of lead(II) bromide as a metal halide containing metal ion M and halide ion X, 0.2 to 2 mL of oleic acid as a ligand, and 0.05 to 0.5 mL of oleylamine as a ligand are mixed and dissolved to prepare a solution (i). On the other hand, for 5 mL of a solvent (poor solvent) that does not dissolve semiconductor nanocrystals, such as isopropanol, toluene, hexane, cyclohexane, etc., 0.01 to 0.5 mL of 3-aminopropyltriethoxysilane as a silane compound A is added to prepare a solution (ii). Then, 0.1 to 1 mL of solution (i) is added to 5 mL of solution (ii) at 0 to 30 °C under the atmosphere and stirred for 5 to 180 seconds simultaneously. When solution (i) is added to solution (ii), semiconductor nanocrystals precipitate, and 3-aminopropyltriethoxysilane, oleic acid, and oleylamine coordinate on the surface of such semiconductor nanocrystals. Then, during stirring under the atmosphere, the alkoxysilyl group of 3-aminopropyltriethoxysilane condenses to obtain a suspension containing precursor particles having a surface layer containing a siloxane bond on the surface of the semiconductor nanocrystals. Here, the surface layer containing a siloxane bond formed here corresponds to the aforementioned first shell layer. The obtained suspension can be centrifuged, for example, to recover the precursor particles. By providing a surface layer containing a siloxane bond, the precursor particles can suppress aggregation after synthesis and fully exhibit luminescence characteristics.

[0065] The obtained precursor particles, a polymer compound, and a silane compound B are mixed to obtain a mixture, and then an aqueous solution containing a salt containing a monovalent cation is added to the mixture to obtain luminescent particles having a surface layer containing a salt containing a monovalent cation and a polymer compound on the surface of the precursor particles. The surface layer provided on the surface of the precursor particles preferably includes a structure having a siloxane bond resulting from the silane compound B.

[0066] For example, a solution containing a mixture of precursor particles and a solvent is mixed with a solution containing a silane compound B and a solvent. Examples of the solvent include toluene, xylene, and the like. Here, the above-described polymer compound is further mixed with the solution containing the mixture of precursor particles and the solvent to prepare a mixture solution. When the polymer compound is contained, it is easier to uniformly coat the precursor particles with a layer containing siloxane bonds formed from the silane compound B. Next, an aqueous solution containing a salt containing a monovalent cation is added to the mixture. There is no particular limitation on the concentration of the salt containing a monovalent cation in such an aqueous solution, and usually, it is preferably in the range of 2 to 50% by mass, and more preferably in the range of 5 to 30% by mass. Further, from the viewpoint of controlling the hydrolysis of the silane compound B, the concentration and addition amount of the aqueous solution containing a salt containing a monovalent cation may be adjusted. By the hydrolysis-silyl groups of the silane compound B condensing to form siloxane bonds, a surface layer containing a polymer of the silane compound B including a salt containing a monovalent cation and a polymer compound is formed on the surface of the precursor particles. Note that the surface layer containing siloxane bonds formed here corresponds to the second shell layer described above. As a result, the luminescent particles of the present invention having a surface layer containing a salt containing a monovalent cation and a polymer compound are formed on the surface of the semiconductor nanocrystal. The surface layer includes siloxane bonds derived from the condensation of the silane compound A, as well as siloxane bonds derived from the condensation of the polymer compound and the silane compound B. Insoluble matters are removed from the obtained reaction mixture, and a solvent (poor solvent) that does not disperse the nanocrystals, such as isopropanol and cyclohexane, is added to the obtained solution to precipitate the luminescent particles. Then, if necessary, the particles are separated by centrifugation or the like, and the solvent is removed to obtain the luminescent particles.

[0067] For example, a solution (iii) is prepared by mixing and dissolving precursor particles, a polymer compound, and a solvent. On the other hand, a solution (iv) is prepared by mixing and dissolving a silane compound B and a solvent. Solution (iv) is added to solution (iii) such that the amount of the silane compound B is 0.1 to 50 parts by mass with respect to 1 part by mass of the precursor particles contained in solution (iii). Subsequently, an aqueous solution containing a salt containing a monovalent cation is added such that the salt containing a monovalent cation is 0.03 to 0.9 parts by mass with respect to 1 part by mass of the precursor particles, and the mixture is stirred at 10 to 60 °C for 5 to 300 minutes. From the viewpoint of controlling the formation of siloxane bonds by condensation of the hydrolyzable groups of the silane compound B, the amount of water in the aqueous solution containing a salt containing a monovalent cation is preferably in the range of 1 to 100 times the mass of the silane compound B. After removing insoluble matters from the obtained reaction mixture by, for example, centrifugation, 2-fold volume % of cyclohexane is added to the recovered supernatant and shaken and stirred to precipitate luminescent particles. Then, the particles are separated by centrifugation or the like, and the solvent is removed to obtain luminescent particles.

[0068] The surface layer containing a structure having a siloxane bond, which the luminescent particles have, includes siloxane bonds derived from the condensation of the silane compound A, and siloxane bonds derived from the condensation of a salt containing a monovalent cation, a polymer compound, and the silane compound B, and corresponds to the sum of the first shell layer and the second shell layer described above. The thickness of the surface layer containing a structure having a siloxane bond, which the luminescent particles of the present invention have, that is, the total thickness of the first shell layer and the second shell layer is preferably 0.5 to 50 nm, more preferably 1.0 to 30 nm. With such a thickness, the stability of the luminescent particles against light can be sufficiently enhanced, and the dispersion stability is excellent. Note that the above thickness can be measured by a high-resolution electron microscope. Note that the total thickness of the first shell layer and the second shell layer can be changed by adjusting the number of atoms (chain length) of the linking structure that links the binding group and the reactive group of the ligand.

[0069] The average particle diameter (volume average diameter) of the luminescent particles of the present invention is preferably 200 nm or less, more preferably 150 nm or less, still more preferably 100 nm or less, and particularly preferably 50 nm or less. The average particle diameter of the luminescent particles is preferably 1 nm or more, more preferably 1.5 nm or more, still more preferably 2 nm or more, and particularly preferably 5 nm or more. When the average particle diameter is within the above range, it is easy to emit light of a desired wavelength. The average particle diameter (volume average diameter) of the luminescent particles is obtained by measuring the particle diameter of each particle with a transmission electron microscope, a scanning electron microscope, or a particle size distribution measuring device and calculating the volume average diameter.

[0070] The luminescent particles of the present invention can be produced using a batch reactor. Further, from the viewpoints of reducing the variation in particle size, preventing the mixing of impurities, production efficiency, temperature control, etc., it is more preferable to produce them using a flow reactor such as a continuous laminar flow, droplet-based, or forced thin film type. During the above reaction, the formation of siloxane bonds is promoted by trace amounts of moisture contained in the solvent or reaction atmosphere, and also by the addition of an aqueous solution containing a salt containing a monovalent cation. The formation of siloxane bonds may also be promoted by heating. In that case, the heating temperature is preferably 20°C or higher and 120°C or lower, more preferably 30°C or higher and 100°C or lower, and still more preferably 40°C or higher and 80°C or lower.

[0071] 3. Ink composition The present invention also relates to an ink composition containing the above-described luminescent particles of the present invention, a photopolymerizable compound, and a photoinitiator.

[0072] Details of the luminescent particles are as described above. The content of the luminescent particles of the present invention in the ink composition is preferably 0.1% by mass or more, 0.5% by mass or more, 1% by mass or more, 3% by mass or more, or 5% by mass or more, and preferably 30% by mass or less, 25% by mass or less, 20% by mass or less, 15% by mass or less, or 10% by mass or less. By setting the content of the luminescent particles within the above range, it becomes difficult for the luminescent particles to aggregate, and the storage stability in the ink composition and the external quantum efficiency of the obtained light-emitting layer (light conversion layer) can also be enhanced.

[0073] 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.

[0074] 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) of 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, a compound having a (meth)acryloyl group is preferred, a monofunctional or polyfunctional (meth)acrylate is more preferred, and a monofunctional or bifunctional (meth)acrylate is 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 as described above. Further, 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.

[0075] 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.

[0076] 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 by (meth)acryloyloxy groups, di(meth)acrylates or tri(meth)acrylates in which two or three hydroxyl groups of a triol compound are substituted by (meth)acryloyloxy groups, and the like can be mentioned.

[0077] 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 hydroxypivalate 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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).

[0083] 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.

[0084] 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.

[0085] 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 3 to 90% by mass, more preferably 5 to 80% by mass, based on the total mass of the photopolymerizable compounds in the ink composition.

[0086] 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, 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, more preferably 150 to 400.

[0087] 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 light-emitting particles, improving the adhesion to a substrate such as plastic or glass, solvent resistance, and abrasion resistance in the light conversion layer containing the ink composition of the present invention, and obtaining excellent optical properties (for example, external quantum efficiency), it is preferable to use two or more radical polymerizable compounds, and it is preferable to use a combination of a monofunctional (meth)acrylate and a polyfunctional (meth)acrylate. The content of the photopolymerizable compound in the ink composition of the present invention is preferably 40% by mass or more and 95% by mass or less, more preferably 50% by mass or more and 94% by mass or less, and even more preferably 60% by mass or more and 93% by mass or less.

[0088] Examples of the photoinitiator contained in the ink composition of the present invention include molecular cleavage type or hydrogen abstraction type photo radical polymerization initiators. Examples of the cleavage-type photo radical polymerization initiator include benzoin isobutyl ether, 2,4-diethyl thioxanthone, 2-isopropyl thioxanthone, 2,4,6-trimethylbenzoyl diphenylphosphine 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, and the like. 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, and the like may be used in combination. Examples of the hydrogen abstraction-type photo radical polymerization initiator include benzophenone, 4-phenylbenzophenone, isophthalophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, and the like. The cleavage-type photo radical polymerization initiator and the hydrogen abstraction-type photo radical polymerization initiator may be used in combination.

[0089] Further, as the photo polymerization initiator, it is preferable to contain a photo polymerization initiator having photo bleaching properties. In this case, the light transmittance of the cured product of the ink composition of the present invention is likely to increase. As the photo polymerization initiator having photo bleaching properties, for example, it is preferable to contain at least one of an oxime ester-based compound or an acylphosphine oxide-based compound having photo bleaching properties. Examples of the oxime ester-based compound having photo bleaching 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-acetoxime), and the like. Examples of 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 low initial coloring degree, it is preferable to contain at least one acylphosphine oxide compound. 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.

[0090] From the viewpoints of solubility in the photopolymerizable compound, curability of the ink composition, and temporal stability (maintenance stability of external quantum efficiency) of the light conversion layer formed from the ink composition, the content of the photoinitiator is preferably 0.1 to 20% by mass, more preferably 0.5 to 15% by mass, still more preferably 1 to 10% by mass, and particularly preferably 1 to 5% by mass with respect to the photopolymerizable compound in the ink composition. Also, from the viewpoint of the curability of the ink composition, the content ratio of the acylphosphine oxide compound in the photoinitiator is preferably 50 to 100% by mass, more preferably 60 to 100% by mass, and still more preferably 70 to 100% by mass.

[0091] 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, a dispersion aid, a thermoplastic resin, and a solvent, as long as the effects of the present invention are not inhibited.

[0092] Examples of the polymerization inhibitor include phenolic compounds such as p-methoxyphenol, cresol, tert-butylcatechol, 3,5-di-tert-butyl-4-hydroxytoluene; quinone compounds such as hydroquinone, tert-butylhydroquinone, p-benzoquinone, 2,5-diphenylbenzoquinone, 1,4-naphthoquinone, anthraquinone; amine compounds such as p-phenylenediamine, 4-aminodiphenylamine, N,N'-diphenyl-p-phenylenediamine; thioether compounds such as phenothiazine, distearylthiodipropionate; 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.

[0093] 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 perspective 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 perspective 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 perspective of not inhibiting the curability of the ink composition.

[0094] Examples of the dispersant include phosphorus atom-containing compounds such as trioctylphosphine, trioctylphosphine 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. The polymer dispersants are available 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 the "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.

[0095] As the surfactant, a compound capable of reducing film thickness unevenness is preferred when forming a thin film containing luminescent particles. 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 "Fujent (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 Corporation, the "DISPARLON (registered trademark) OX" series manufactured by Kusumoto Chemical Co., 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.

[0096] The light-scattering particles are preferably optically inactive inorganic fine particles. The light-scattering particles can scatter the light from the light source unit 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.; 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 oxides; 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.

[0097] When the light-scattering particles are contained, for example, when the ink composition of the present invention is used as a material for forming a color filter layer, from the viewpoint of suppressing the transmission of blue light of the backlight, it is preferably in the range of 1 to 10% by mass with respect to the whole ink composition, more preferably in the range of 2 to 7.5% by mass, and particularly preferably in the range of 3 to 5% by mass. When the ink composition of the present invention is used as a material for forming a light conversion sheet, from the viewpoint of extracting blue light of the backlight, it is preferably in the range of 0.1 to 5% by mass with respect to the whole ink composition, 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.

[0098] 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 tristthioglycolate, trimethylolpropane tristthiopropionate, 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, etc. 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 even more preferably 5 to 20% by mass based on the total amount of the photopolymerizable compounds contained in the ink composition.

[0099] Examples of the sensitizer include amines that do not undergo an addition reaction with the photopolymerizable compound, such as trimethylamine, methyldimethanolamine, triethanolamine, p - diethylaminoacetophenone, ethyl p - dimethylaminobenzoate, isoamyl p - dimethylaminobenzoate, N,N - dimethylbenzylamine, 4,4’ - bis(diethylamino)benzophenone, and the like. Examples of the dispersion aid include organic pigment derivatives such as phthalimidomethyl derivatives, phthalimidosulfonic acid derivatives, phthalimido N - (dialkylamino)methyl derivatives, and phthalimido N - (dialkylaminoalkyl)sulfonic acid amide derivatives. Examples of the thermoplastic resin include urethane - based resins, acrylic - based resins, polyamide - based resins, polyimide - based resins, styrene - maleic acid - based resins, styrene - maleic anhydride - based resins, polyester acrylate - based resins, and the like.

[0100] 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 entire 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.

[0101] The method for preparing the ink composition of the present invention is not particularly limited and can be prepared by blending each of the above-described components. For example, the luminescent particles are isolated from the luminescent particles in the state of a dispersion liquid and dispersed in a 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, a photopolymerization initiator and, if necessary, other components are added and stirred and mixed to prepare the composition. When containing light-scattering particles, a mill base in which the light-scattering particles and a polymer dispersant are mixed and dispersed in the photopolymerizable compound by a bead mill is separately prepared, and the photopolymerizable compound, the photopolymerization initiator, and the like are mixed with the luminescent particles to prepare the composition.

[0102] 4. Light conversion layer The ink composition of the present invention can be applied onto a substrate to form a film, and the film can be cured to obtain a cured product. The light conversion layer containing the cured product of the ink composition of the present invention is suitable for use in color filters and wavelength conversion films. Examples of the method for applying the ink composition of the present invention onto a substrate include spin coating, die coating, extrusion coating, roll coating, wire bar coating, gravure coating, spray coating, dipping, inkjet method, printing method, and the like. When applying, if necessary, a hydrocarbon, a halogenated hydrocarbon, an ether, an alcohol, a ketone, an ester, an aprotic polar compound, or the like may be added as a solvent to the ink composition. When a solvent is added, after applying the ink composition onto the substrate, natural drying, drying under heating, or drying under reduced pressure is performed.

[0103] 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 the organic material include polyethylene terephthalate, polycarbonate, polyimide, polyamide, polymethyl methacrylate, polystyrene, polyvinyl chloride, polytetrafluoroethylene, polychlorotrifluoroethylene, polyarylate, polysulfone, triacetyl cellulose, cellulose, polyether ether ketone, etc. Examples of the inorganic material include silicon, glass, calcite, etc.

[0104] 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 formation of the light conversion layer.

[0105] The color filter using the ink composition of the present invention as a forming material may be provided with an ink-repellent layer made of a material having ink-repellent properties narrower in width than the light-shielding portion on the pattern of the light-shielding portion. Further, instead of providing the ink-repellent layer, after forming a photocatalyst-containing layer as a wettability variable layer in a solid coating form in a region including the pixel portion forming region, the photocatalyst-containing layer is irradiated with light through a photomask for exposure, and the hydrophilicity of the pixel portion forming region may be selectively increased. Examples of the photocatalyst include titanium oxide, zinc oxide, etc. The color filter may be provided with an ink-receiving layer containing hydroxypropyl cellulose, polyvinyl alcohol, gelatin, etc. between the substrate and the pixel portion. The color filter may be provided with a protective layer on the pixel portion. This protective layer is provided to flatten the color filter and prevent the elution of the components contained in the pixel portion, or the components contained in the pixel portion and the components contained in the photocatalyst-containing layer into the liquid crystal layer. As the material constituting the protective layer, those used as known protective layers for color filters can be used. In the production of the color filter and the light conversion layer, in addition to the inkjet method, the pixel portion may be formed by a photolithography method. In this case, first, the ink composition of the present invention is applied in layers on a substrate to form a film, and then the film is exposed in a pattern and developed using a developer, whereby a pixel portion composed of a cured product of the ink composition of the present invention is formed.

[0106] 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 in the temperature range of 50 to 250 °C and the treatment time is 30 seconds to 12 hours. 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. Further, the obtained wavelength conversion films may be laminated, or may be bonded to another substrate and used.

[0107] When the wavelength conversion film using the ink composition of the present invention as a forming material is used in a laminated structure, such a laminated structure may have any layers such as a substrate, a barrier layer, and a light scattering layer. The material constituting the substrate is as described above. Examples of the barrier layer include polyethylene terephthalate and glass. 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 laminated structure, for example, a structure in which a light conversion layer using the ink composition of the present invention as a forming material 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 laminated structure of the present embodiment. In the laminated structure 40, the 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 particles 442, and the light scattering particles 441 and the luminescent particles 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.

[0108] The laminated structure formed of the ink composition of the present invention is suitable for applications such as a prism sheet, a light guide plate, a laminated structure containing the light-emitting particles of the present invention, and a light-emitting device having a light source. Examples of the light source include a light-emitting diode, a laser, and an electroluminescent device. In addition, the laminated structure formed of the ink composition of the present invention 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 laminated 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. 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 laminated structure, it is 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.

[0109] 5. Light-emitting element Hereinafter, a case where a color filter pixel portion of a light-emitting element including a 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 containing 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. In FIG. 2, for convenience, the dimensions and their ratios of each part are exaggerated and may be different from the actual ones. In addition, 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 addition, in FIG. 2, the description of the hatching indicating the cross section is omitted in order to avoid complication of the drawing.

[0110] 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 particles 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 of the light-emitting particles having a siloxane bond in the semiconductor nanocrystal may be a surface layer containing a salt having a monovalent cation and having one layer of a layer having a siloxane bond, or may be a surface layer having a plurality of layers.

[0111] The EL light source unit 200 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 in this order. 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 sequence 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 particles contained in the light conversion layer 12. Hereinafter, each layer will be sequentially described.

[0112] [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.

[0113] 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 with 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, either one or both of the lower substrate 1 and the upper substrate 13 may be omitted.

[0114] 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 electrode 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, a capacitor 701, a driving transistor 702, and a switching transistor 708 are provided in the vicinity of the intersection of each signal line 706 and each scanning line 707.

[0115] The capacitor 701 has one electrode connected to the gate electrode of the driving transistor 702 and the other electrode 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 for supplying the driving current, and its drain electrode connected to the anode 2 of the EL light source unit 200.

[0116] 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. In addition, in the present 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.

[0117] The scanning line driving circuit C2 supplies or cuts off a scanning voltage corresponding to a scanning signal to the gate electrode of the switching transistor 708 via the scanning line 707, thereby turning on or off the switching transistor 708. As a result, the scanning line driving circuit C2 adjusts the timing at which the signal line driving circuit C1 writes a signal voltage. On the other hand, the signal line driving circuit C1 supplies or cuts off a signal voltage corresponding to a video signal to the gate electrode of the driving transistor 702 via the signal line 706 and the switching transistor 708, and adjusts the amount of the signal current supplied to the EL light source unit 200.

[0118] 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 as a signal current from the power supply line 703 to the EL light source unit 200. As a result, the EL light source unit 200 emits light according to the supplied signal current.

[0119] <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 (SnO 2 ), zinc oxide (ZnO), etc.; 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, an anode 2 having a predetermined pattern may be formed by a photolithography method or a method using a mask.

[0120] [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 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), SnO 2 , metals such as ZnO, or metal oxides, etc. 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, a range of 0.1 to 1000 nm is preferable, and a range of 1 to 200 nm is more preferable. The cathode 8 can be formed by a dry film-forming method such as an evaporation 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.

[0121] [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 needed and 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.

[0122] 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 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 hole injection material is applied by an inkjet printing method (piezo method or thermal type droplet ejection method), spin coating method, casting method, LB method, relief printing method, gravure printing method, screen printing method, 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.

[0123] [Hole transport layer 4] The positive hole transport layer 4 has the 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 the function of preventing the transport of electrons. Note that the positive hole transport layer 4 may be provided as needed and can also be omitted.

[0124] As the constituent material (positive hole transport material) of the positive hole transport layer 4, it is preferable to use a material with a higher positive hole transport ability than electron transport ability. Examples of such positive hole transport materials include aromatic amines, carbazole derivatives, aromatic hydrocarbons, stilbene derivatives, etc., and π-electron-excessive heteroaromatics or aromatic amines can be preferably used. Specific examples of the positive 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 positive hole transport material, triphenylamine derivatives, polymers or copolymers of triphenylamine derivatives with substituents introduced are preferable, and polymers of triphenylamine derivatives with substituents introduced are more preferable.

[0125] There is no particular limitation on the average thickness of the positive 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 positive hole transport layer 4 may be a single layer or a laminated structure in which two or more layers are laminated. Such a positive hole transport layer 4 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 positive hole injection layer 3.

[0126] [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 may be omitted. Examples of the constituent material (electron injection material) of the electron injection layer 7 include, for example, Li 2 O, LiO, Na 2 S, Na 2 Se, NaO and other alkali metal chalcogenides; CaO, BaO, SrO, BeO, BaS, MgO, CaSe and other alkaline earth metal chalcogenides; CsF, LiF, NaF, KF, LiCl, KCl, NaCl and other alkali metal halides; 8-hydroxyquinolinolato lithium (Liq) and other alkali metal salts; CaF 2 , BaF 2 , SrF 2 , MgF 2 , BeF 2 and other alkaline earth metal halides and the like. 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 preferable.

[0127] There is no particular limitation on the average thickness of the electron injection layer 7, and usually, a range of 0.1 to 100 nm is preferable, a range of 0.2 to 50 nm is more preferable, and a range of 0.5 to 10 nm is even more preferable. Further, 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 positive hole injection layer 3.

[0128] [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. Further, the electron transport layer 6 may have a function of preventing hole transport. Note that the electron transport layer 6 may be provided as necessary and can also 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 hole transport ability. Examples of the electron transport material include π-electron deficient heteroaromatics 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, etc.

[0129] 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 of 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; metal oxides such as titanium oxide (TiO x ) and zinc oxide can be preferably used.

[0130] 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.

[0131] When the hole injection layer 3 and the electron injection layer 7 are provided in the light-emitting element 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 enhanced. As a result, the light-emitting efficiency of the light-emitting layer 5 is further improved, enabling high-brightness light emission, and a long-life light-emitting element can be obtained.

[0132] [Light-emitting layer 5] The light-emitting layer 5 has a function of generating light by utilizing 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, 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 includes at least one selected from the group consisting of organic low-molecular fluorescent materials, organic high-molecular fluorescent materials, and organic phosphorescent materials.

[0133] Examples of the compound capable of converting singlet excitation energy into light include an organic low-molecular fluorescent material or an organic high-molecular fluorescent material that emits fluorescence. As the organic low-molecular fluorescent material, a compound 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 is preferable.

[0134] 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. can be mentioned.,

[0135] 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.

[0136] 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.

[0137] The light-emitting layer 5 may contain a host material. The host material provides a site for 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 these excitons 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.

[0138] 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 thereof 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.,

[0139] The average thickness of the light-emitting layer 5 is usually preferably in the range of 1 to 100 nm, 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.

[0140] 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°.

[0141] The light-emitting element 100 may further have a hole-blocking layer between the light-emitting layer 5 and the electron transport layer 6. The hole-blocking layer has a function of regulating the holes transported from the hole transport layer 4 from passing through the light-emitting layer 5 and moving to the electron transport 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 transport 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 light-emitting efficiency of the light-emitting layer 5 can be further improved. As the constituent material of the hole-blocking layer, the above-described electron transport materials can be used alone or in combination of two or more. There is no particular limitation on the average thickness of the hole-blocking layer. Usually, the range of 1 to 500 nm is preferable, the range of 2 to 300 nm is more preferable, and the 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 injection layer 3. Also, 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.

[0142] <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 the pixel portion 20, a first pixel portion 20a that converts light of the wavelength in the above range and emits red light, a second pixel portion 20b that converts light of the wavelength in the above range and emits green light, and a third pixel portion 20c that transmits light of the wavelength in 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.

[0143] 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 light-emitting particles 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 first light-emitting particles 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 second light-emitting particles 90b and second light-scattering particles 21b dispersed in the second curing component 22b. 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.

[0144] The first light-emitting particles 90a are red light-emitting particles that absorb light with a wavelength in the range of 420 to 480 nm and emit 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. Also, the second light-emitting particles 90b are green light-emitting particles that absorb light with a wavelength in the range of 420 to 480 nm and emit 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.

[0145] The content of the light-emitting 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 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 external quantum efficiency improvement effect and excellent emission intensity. The content of the light-emitting particles is preferably 30% by mass or less, more preferably 25% by mass or less, still more preferably 20% by mass or less, and particularly preferably 15% by mass or less based on the total mass of the ink composition, from the viewpoints of excellent reliability of the pixel portions 20a and 20b and excellent emission intensity.

[0146] 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.

[0147] 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, when a light source that emits light having a wavelength in the range of 420 to 480 nm is used, the third pixel portion 20c functions as a blue pixel portion. 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 particles of the present invention. The cured product does not contain light-emitting particles 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. As long as the transmittance of the third curing component 22c with respect to light having a wavelength in the range of 420 to 480 nm is 30% or more, a polymer of the photopolymerizable compound and organic components (dispersant, unreacted photopolymerizable compound, etc.) in the ink composition may be included. 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. From the viewpoint of further reducing the light intensity difference at the viewing angle, 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 still more preferably 5% by mass or more based on the total mass of the cured product of the non-luminous ink composition. From the viewpoint of further reducing light reflection, the content of the light-scattering particles is preferably 80% by mass or less, more preferably 75% by mass or less, and still more preferably 70% by mass or less based on the total mass of the cured product of the non-luminous ink composition. Note that the transmittance of the third pixel portion 20c can be measured by a microscopic spectroscope.

[0148] 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 still more preferably 3 μm or more. The thickness of the pixel portions (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.

[0149] 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 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 (e.g., reactive silicone emulsion), etc. The thickness of the light-shielding portion 30 is preferably 1 μm or more and 15 μm or less. Examples of the method for forming the light-shielding portion include forming a thin film of a metal such as chromium or a resin composition containing light-shielding particles in a region that becomes the boundary between a plurality of pixel portions on one surface side of the substrate, and patterning this thin film. The metal thin film can be formed, for example, by sputtering, vacuum deposition, etc., and the thin film of the resin composition containing light-shielding particles can be formed, for example, by methods such as coating and printing. Examples of the method for patterning include photolithography.

[0150] [Method for forming the light conversion layer 12] The light conversion layer 12 including the above 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 above-described non-light-emitting ink composition that does not contain the light-emitting particles of the present invention.

[0151] As a coating method for obtaining a coating film of the ink composition of the present invention, there are 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, and the like.

[0152] 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.

[0153] 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. When droplets are ejected at such a temperature, the crystallization of various components contained in the ink composition of the present invention can be suppressed. Also, the relative humidity at the time of forming the coating film is not particularly limited, and usually, it is preferably in the range of 0.01 ppm to 80%, more preferably in the range of 0.05 ppm to 60%, even 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 equal to or higher than the above lower limit value, the control of the conditions at the time of forming the coating film becomes easy. On the other hand, when the relative humidity is equal to or lower than the above upper limit value, the amount of moisture adsorbed on the coating film that can adversely affect the obtained light conversion layer 12 can be reduced.

[0154] When a hydrocarbon, a halogenated hydrocarbon, an ether, an alcohol, a ketone, an ester, an aprotic polar compound, etc. are added as a solvent to the ink composition, after applying the ink composition onto a substrate and before curing it, natural drying, drying under heating or drying under reduced pressure is carried out. From the viewpoint of productivity, it is preferable to carry out 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.

[0155] Curing of the ink composition of the present invention can be carried out 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. From the viewpoints of reducing the heat load on the coating film and low power consumption, an LED is preferable.

[0156] The wavelength of the light to be irradiated is preferably 200 nm or more and 440 nm or less. Also, from the viewpoints that the light intensity can sufficiently cure without unevenness in the curing degree of the coating film surface and inside and can easily maintain the smoothness of the coating film surface, 0.2 to 2 kW / cm 2 is preferable, and 0.4 to 1 kW / cm 2 is more preferable. The irradiation amount (exposure amount) of light is preferably 10 mJ / cm 2 or more and 4000 mJ / cm 2 or less. 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 viewpoints of suppressing oxygen inhibition on the coating film surface and oxidation of the coating film, it is preferable to carry out it 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.

[0157] As described above, since the ink composition of the present invention is excellent in heat stability, good light emission can be realized even 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 particles and it is easy to obtain a flat pixel portion 20.

[0158] Furthermore, when the light-emitting particles contained in the first pixel portion 20a and the second pixel portion 20b include 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 particles of the present invention, red light and green light with high color purity can be extracted without mixing of blue light.

[0159] The light-emitting element 100 can be configured as a bottom emission type instead of a top emission type. Further, the light-emitting element 100 can use other light sources instead of the EL light source portion 200.

[0160] 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.

[0161] As described above, the light-emitting particles of the present invention, the method for manufacturing the light-emitting particles, the ink composition containing the light-emitting particles, the light conversion layer containing the cured product of the ink composition, and the color filter, wavelength conversion film, and light-emitting element provided with the light conversion layer have been described. However, the present invention is not limited to the configuration of the above-described embodiments. For example, the luminescent particles, ink composition containing the luminescent particles, light conversion layer containing the cured product of the ink composition, color filter provided with the light conversion layer, wavelength conversion film, and light emitting element of the present invention may each have any other arbitrary configuration added in the configuration of the above-described embodiment, or may be replaced with any configuration that exhibits the same function. Further, the method for manufacturing the luminescent particles of the present invention may have any other arbitrary-purpose step in the configuration of the above-described embodiment, or may be replaced with any step that exhibits the same effect.

Example

[0162] Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited only to the following examples. Unless otherwise specified, "parts" and "%" are based on mass.

[0163] A. Production Example of Polymer Compound [Production Example 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, which had been 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 that was a pale yellow solid at 25 °C (hereinafter referred to as "Polymer 1"). 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> Apparatus: "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

[0164] [Production Example 2] 6 parts by mass of polyethyleneimine (trade name: "Epomin (registered trademark) SP-018", 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 purging 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") at 25 °C. When the weight-average molecular weight of Polymer 2 was measured by GPC in the same manner as in Synthesis Example 1, it was 25,000.

[0165] [Production Example 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 Synthesis Example 1, it was 10,000.

[0166] B. Production Examples of Luminescent Particles a to c [Production Example 4 (Preparation of Dispersion Liquid a Containing Luminescent Particles 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 homogeneous 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) was added. The temperature was raised to 140 °C and stirred until a homogeneous solution was obtained. To this mixed solution containing lead(II) bromide, 1.1 mL of the above formamidinium-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. The resulting suspension was centrifuged (10,000 rpm, 3 minutes), and after removing the supernatant, 20 mL of toluene was added to the obtained solid (luminescent particles a), and shaken and stirred to disperse. The obtained colloidal solution was centrifuged at 25 °C and 10,000 rpm for 3 minutes, and the supernatant was recovered to obtain a dispersion liquid a in which 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 FAPbBr 3 ("FA" is (NH 2 ) 2 CH, that is, formamidinium.) It was found that. In addition, for 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. That is, in the dispersion liquid a, FAPbBr having a perovskite crystal structure 3 is contained as a core, and luminescent particles a having a surface layer containing a siloxane bond are dispersed in a colloidal state. When the dispersion liquid a was analyzed with a particle size distribution measuring device (NanoTrack Wave II), its average particle size was 17 nm.

[0167] [Production Example 5 (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 other 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. After further drying under reduced pressure for 20 minutes, it was returned to atmospheric pressure while maintaining the argon atmosphere and heated at 140 °C. To this mixed solution containing lead(II) bromide, 1.5 mL of the above 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), 20 mL of toluene was added to the solid matter (luminescent particles b) obtained by removing the supernatant, 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 the 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 nanocrystals constituting the luminescent particles b had a perovskite crystal structure of CsPbBr 3 It was found that it is. In addition, 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. This Si is considered to be derived from the siloxane bond generated by the hydrolysis of APTES. That is, in the dispersion liquid b, CsPbBr having a perovskite crystal structure 3 having a core and a surface layer containing a siloxane bond is dispersed in a colloidal state. When the luminescent particles b were analyzed with a particle size distribution analyzer (NanoTrack Wave II), the average particle size was found to be 15 nm.

[0168] [Production Example 6 (Preparation of Dispersion Liquid c Containing Luminescent Particles c)] Under an argon atmosphere, 0.09 g of methylamine hydrobromide (MABr), 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). 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 methylamine-oleic acid solution. On the other 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, dried under reduced pressure at 90 °C for 10 minutes, and then 1.5 mL of APTES was added. After further drying under reduced pressure for 20 minutes, the pressure was returned to atmospheric pressure while maintaining the argon atmosphere, and the mixture was heated at 140 °C. To the mixed solution containing lead(II) bromide, 1.5 mL of the above methylamine-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 the obtained suspension was centrifuged (10,000 rpm, 1 minute), 20 mL of toluene was added to the solid (luminescent particles c) 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 recovered to obtain a dispersion liquid c in which the luminescent particles c were dispersed in a colloidal state. When X-ray powder diffraction was performed on the luminescent particles c, it was found that the semiconductor nanocrystals constituting the luminescent particles c had a perovskite crystal structure of MAPbBr 3 It was found that it is. In addition, the element distribution of the luminescent particles c was evaluated by STEM-EDS, and it was confirmed that Si was present on the surface of the luminescent particles c. This Si is considered to be derived from the siloxane bond generated by the hydrolysis of APTES. That is, in the dispersion liquid c, MAPbBr having a perovskite crystal structure 3Luminescent particles c having a core and a surface layer containing a siloxane bond are dispersed in a colloidal state. When the luminescent particles c were analyzed with a particle size distribution measuring device (NanoTrac Wave II), the average particle size was 16 nm.

[0169] C. Production Examples of the 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. 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. Thereafter, 0.5 mL of a silane compound 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 mass% aqueous cesium bromide solution were added, and the mixture was stirred at room temperature for 2 hours.

[0170]

Chemical Formula

[0171] The obtained mixed solution was centrifuged at 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 the luminescent particles a. This surface layer corresponds to the second shell layer described above. Regarding the 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 the luminescent particles 1. When the thickness of the surface layer was measured, it was about 4 nm. Also, regarding the luminescent particles 1, since weight loss was confirmed in the range of 200 to 550 °C by thermogravimetric differential thermal analysis (TG-DTA; heating rate 10 °C / min, under nitrogen atmosphere) measurement, it was suggested that an organic component was contained. On the other hand, by thermodecomposition gas chromatograph mass spectrometer (TD / Py-GC / MS) measurement, polymer 1 was identified as a component. Furthermore, it was confirmed by fluorescent X-ray analysis that cesium was contained as a component in the luminescent particles 1. When the luminescent particles 1 were analyzed by a particle size distribution measuring device (NanoTrac Wave II), the average particle size was 28 nm.

[0172] [Example 2] In Example 1, a dispersion liquid 2 containing luminescent particles 2 was obtained by performing the same operations as in Example 1, except that 0.025 mL of a 10 mass% methylammonium bromide aqueous solution was added instead of 0.025 mL of a 10 mass% cesium bromide aqueous solution. Regarding the luminescent particles 2, 1 By 1H-NMR measurement, peaks derived from methylamine (MA) at 2.3 ppm and formamidine (FA) at 7.8 ppm were respectively attributed, and from the integral value ratio, it was confirmed that each component had a molar ratio of FA:MA ≒ 6:1.

[0173] [Example 3] In Example 1, a dispersion liquid 3 containing luminescent particles 3 was obtained by performing the same operations as in Example 1, except that 0.025 mL of a 10 mass% formamidine bromide aqueous solution was added instead of 0.025 mL of a 10 mass% cesium bromide aqueous solution. Regarding the luminescent particles 3, 1 By 1H-NMR measurement, an increase in the integral value of the peak derived from formamidine (FA) was confirmed.

[0174] [Example 4] In Example 1, a dispersion liquid 4 containing luminescent particles 4 was obtained by performing the same operations as in Example 1, except that 0.025 mL of a 10% by mass aqueous solution of guanidine bromide was added instead of 0.025 mL of a 10% by mass aqueous solution of cesium bromide. Regarding the luminescent particles 4, 13 By 13C-NMR measurement, peaks derived from guanidine (GA) at 160 ppm and formamidine (FA) at 159 ppm were respectively attributed, and it was confirmed from the integral value ratio that each component had a molar ratio of FA:GA ≒ 13:1.

[0175] [Example 5] In Example 1, 5 mL of the dispersion liquid b obtained by the method of Production Example 5 was used instead of the dispersion liquid a, and 0.025 mL of a 2% by mass aqueous solution of cesium iodide was added instead of 0.025 mL of a 10% by mass aqueous solution of cesium bromide. Then, the same operations as in Example 1 were performed to obtain a dispersion liquid 5 containing luminescent particles 5. Regarding the luminescent particles 5, it was confirmed by fluorescent X-ray analysis that cesium and iodine were contained as components.

[0176] [Example 6] In Example 1, 5 mL of the dispersion liquid c obtained by the method of Production Example 6 was used instead of the dispersion liquid a, and then the same operations as in Example 1 were performed to obtain a dispersion liquid 6 containing luminescent particles 6. Regarding the luminescent particles 6, it was confirmed by fluorescent X-ray analysis that cesium was contained as a component.

[0177] [Example 7] In Example 1, 0.8 g of a block copolymer (S2VP, manufactured by PolymerSource; hereinafter referred to as "polymer 4") having a structure represented by the following formula was used instead of polymer 1, and 0.025 mL of a 10% by mass aqueous solution of methylammonium bromide was added instead of 0.025 mL of a 10% by mass aqueous solution of cesium bromide. Then, the same operations as in Example 1 were performed to obtain a dispersion liquid 7 containing luminescent particles 7.

[0178] [Chemical formula]

[0179] [Example 8] In Example 1, 0.8 g of “EFKA (registered trademark) PX4701” (manufactured by BASF Japan Ltd.) (hereinafter referred to as “Polymer 5”) was used instead of Polymer 1, and 0.025 mL of a 10% by mass aqueous solution of methylammonium bromide was added instead of 0.025 mL of a 10% by mass aqueous solution of cesium bromide. Otherwise, the same operations as in Example 1 were performed to obtain Dispersion 8 containing Luminescent Particles 8.

[0180] [Example 9] In Example 1, 0.8 g of Polymer 2 was used instead of Polymer 1, and 0.025 mL of a 10% by mass aqueous solution of methylammonium bromide was added instead of 0.025 mL of a 10% by mass aqueous solution of cesium bromide. Otherwise, the same operations as in Example 1 were performed to obtain Dispersion 9 containing Luminescent Particles 9.

[0181] [Example 10] In Example 1, 0.8 g (in terms of non-volatile content) of Polymer 3 was used instead of Polymer 1, and 0.025 mL of a 10% by mass aqueous solution of methylammonium bromide was added instead of 0.025 mL of a 10% by mass aqueous solution of cesium bromide. Otherwise, the same operations as in Example 1 were performed to obtain Dispersion 10 containing Luminescent Particles 10.

[0182] [Comparative Example 1] In Example 1, 0.025 mL of water was added instead of 0.025 mL of a 10% by mass aqueous solution of cesium bromide. Otherwise, the same operations as in Example 1 were performed to obtain Dispersion 11 containing Luminescent Particles 11.

[0183] [Comparative Example 2] In Example 1, 5 mL of Dispersion b obtained by the method of Production Example 5 was used instead of Dispersion a, and 0.025 mL of water was added instead of 0.025 mL of a 10% by mass aqueous solution of cesium bromide. Otherwise, the same operations as in Example 1 were performed to obtain Dispersion 12 containing Luminescent Particles 12.

[0184] [Comparative Example 3] In Example 1, except that 5 mL of dispersion liquid c obtained by the method of Production Example 6 was used instead of dispersion liquid a, and 0.025 mL of water was added instead of 0.025 mL of 10 mass% cesium bromide aqueous solution, the same operation as in Example 1 was carried out to obtain dispersion liquid 13 containing luminescent particles 13.

[0185] [Comparative Example 4] In Comparative Example 1, except that 0.025 mL of water was added instead of 0.025 mL of 10 mass% cesium bromide aqueous solution and 2.5 mg of lead(II) bromide was also added together, the same operation as in Example 1 was carried out to obtain dispersion liquid 14 containing luminescent particles 14.

[0186] For each of the obtained dispersion liquids 1 to 14, using an absolute PL quantum yield measuring device (manufactured by Hamamatsu Photonics K.K., "Quantaurus-QY"), the absolute quantum yield (PLQY), the peak wavelength (λmax) of the emission spectrum, and the 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 together with the crystal composition and average particle diameter of luminescent particles 1 to 14.

[0187]

Table 1

[0188] D. Production and Evaluation of Ink Composition D-1. Preparation Example of Ink Composition [Example 11] 4 mL of hexane and 2 mL of dispersion liquid 1 obtained in Example 1 were added to a glass vial equipped with a stir bar and stirred, and the obtained suspension was centrifuged at 4000 rpm for 1 minute. By removing the supernatant, solid X1 containing luminescent particles 1 was obtained. In a clean room that cuts off light with a wavelength of 500 nm or less, 26.7 parts by mass of isobornyl acrylate (IBXA; "Light Acrylate IB-XA" manufactured by Kyoeisha Chemical Co., Ltd.), 50 parts by mass of dimethyloltricyclodecane diacrylate (DCPA; "Light Acrylate DCP-A" manufactured by Kyoeisha Chemical Co., Ltd.), 20 parts by mass of trimethylolpropane-ethylene oxide modified triacrylate (TMP(EO) 3 TA; "MIRAMER M-3130" manufactured by MIWON Specialty Chemical Co., Ltd.) and 3 parts by mass of diphenyl(2,4,6-trimethoxybenzoyl)phosphine oxide (TPO; "Omnirad TPO" manufactured by IGM Resin Co., Ltd.) were added, and the mixture was stirred and dissolved at room temperature. Subsequently, 0.3 part by mass of the above solid X1 was added, stirred and dissolved at room temperature, and filtered through a membrane filter (pore size 0.50 μm) to prepare Ink Composition 1 containing Luminescent Particles 1.

[0189] [Examples 12 to 20, Comparative Examples 5 to 8] In Example 11, Ink Compositions 2 to 10 and Ink Compositions C1 to C4 were prepared in the same manner as in Example 11, except that Dispersions 2 to 14 obtained in Examples 2 to 10 and Comparative Examples 1 to 4 were used instead of Dispersion 1 obtained in Example 1.

[0190] [Example 21] In Example 12, 27.3 parts by mass of isobornyl acrylate (IBXA; "Light Acrylate IB-XA" manufactured by Kyoeisha Chemical Co., Ltd.), 51 parts by mass of dimethyloltricyclodecane diacrylate (DCPA; "Light Acrylate DCP-A" manufactured by Kyoeisha Chemical Co., Ltd.), 20.4 parts by mass of trimethylolpropane-ethylene oxide modified triacrylate (TMP(EO) 3 TA; "MIRAMER M-3130" manufactured by MIWON Specialty Chemical Co., Ltd.) and 1 part by mass of diphenyl(2,4,6-trimethoxybenzoyl)phosphine oxide (TPO; "Omnirad TPO" manufactured by IGM Resin Co., Ltd.) were added, and Ink Composition 11 was prepared in the same manner as in Example 12.

[0191] [Example 22] In Example 12, 26.1 parts by mass of isobornyl acrylate (IBXA; "Light Acrylate IB-XA" manufactured by Kyoeisha Chemical Co., Ltd.), 49 parts by mass of dimethyloltricyclodecane diacrylate (DCPA; "Light Acrylate DCP-A" manufactured by Kyoeisha Chemical Co., Ltd.), 19.6 parts by mass of trimethylolpropane-ethylene oxide modified triacrylate (TMP(EO) 3 TA; "MIRAMER M-3130" manufactured by MIWON Specialty Chemical Co., Ltd.) and 5 parts by mass of diphenyl(2,4,6-trimethoxybenzoyl)phosphine oxide (TPO; "Omnirad TPO" manufactured by IGM Resin Co., Ltd.) were added, and Ink Composition 12 was prepared in the same manner as in Example 12 except for this.

[0192] D-2. Evaluation of the Damp Heat Resistance of the Ink Composition The obtained Ink Compositions 1 to 12 and Ink Compositions C1 to C4 were placed in glass vials, and using an absolute PL quantum yield measuring device ("Quantaurus-QY" manufactured by Hamamatsu Photonics K.K.), the absolute quantum yields (PLQY) immediately after preparation and after storage at 60°C and 90% RH for 1 month (30 days) under light shielding were measured, and the PLQY retention rate was calculated by the following formula, and the damp heat resistance was evaluated according to the following criteria. The results are shown in Table 2. PLQY retention rate (%) = 100 × (PLQY of the ink composition after storage / PLQY of the ink composition before storage) <Evaluation Criteria for the Damp Heat Resistance of the Ink Composition> 〇: QY retention rate 80% or more △: QY retention rate 70% or more and less than 80% ×: QY retention rate less than 70%

[0193] E. Manufacture and Evaluation of the Light Conversion Layer E-1. Manufacture of the Light Conversion Layer The respective ink compositions obtained in Examples 11 to 22 and Comparative Examples 5 to 8 were dropped onto a glass substrate Eagle XG (manufactured by Corning), another glass substrate Eagle XG was placed thereon, and UV light with a main wavelength of 395 nm was irradiated in a nitrogen atmosphere so that the integrated light amount became 10 J / cm 2 to produce a 100-μm-thick light conversion layer containing luminescent particles and composed of a cured product of each ink composition.

[0194] E-2. Evaluation of Luminescence Characteristics For each light conversion layer, the absolute quantum yield (PLQY) was measured at an excitation wavelength of 450 nm using an absolute PL quantum yield measuring device (manufactured by Hamamatsu Photonics K.K., "Quantaurus-QY"), and the PLQY retention rate (%) when forming each light conversion layer from each ink composition was calculated by the following formula. PLQY retention rate (%) = 100 × (PLQY of light conversion layer / PLQY of ink composition)

[0195] E-3. Evaluation of Light Resistance For each light conversion layer, using a light resistance tester (manufactured by CCS), blue light with a peak wavelength of 450 nm in the emission spectrum was irradiated at a stage temperature of 30°C and 400 mW / cm 2 for 25 hours in air. The PLQY of the light conversion layer after light irradiation was measured at an excitation wavelength of 450 nm using an absolute PL quantum yield measuring device (manufactured by Hamamatsu Photonics K.K., "Quantaurus-QY"), and the PLQY retention rate (%) was calculated by the following formula. PLQY retention rate (%) = 100 × (PLQY of light conversion layer after light irradiation / PLQY of light conversion layer before light irradiation) The above results are summarized in Table 2.

[0196]

Table 2

[0197] The luminescent particles 1 to 10 included in the dispersions of Examples 1 to 10 all include, as a surface layer, a first shell layer having a structure containing a siloxane bond resulting from APTES, and a second shell layer having a structure containing a siloxane bond resulting from MS-51 and containing a salt having a monovalent cation. That is, the luminescent particles 1 to 10 are luminescent particles having a surface layer containing a structure having a siloxane bond on the surface of a semiconductor nanocrystal composed of a metal halide, and the surface layer contains a salt having a monovalent cation. On the other hand, although the luminescent particles 11 to 13 included in the dispersions of Comparative Examples 1 to 3 have a surface layer containing a structure having a siloxane bond on the surface of a semiconductor nanocrystal composed of a metal halide, they are luminescent particles in which the surface layer does not contain a salt having a monovalent cation. Further, the luminescent particles 14 included in the dispersion of Comparative Example 4 have a surface layer containing a structure having a siloxane bond on the surface of a semiconductor nanocrystal composed of a metal halide, and the surface layer contains a salt having a divalent cation but does not contain a salt having a monovalent cation.

[0198] As shown in Table 2, the ink compositions 1 to 12 of Examples 11 to 22 containing the luminescent particles 1 to 10 have a higher PLQY retention rate after being stored at 60 °C and 90% RH for one month under light shielding compared to the ink compositions C1 to C4 of Comparative Examples 5 to 8 containing the luminescent particles 11 to 14. From this, it can be understood that the luminescent particles 1 to 10 are superior in moisture and heat resistance compared to the luminescent particles 11 to 14. Further, the ink compositions of Examples 11 to 19 and 21 to 22 have a higher PLQY retention rate compared to the ink composition 10 of Example 20. From this, it can be understood that the luminescent particles 1 to 9 included in the ink compositions 1 to 9, 11 to 12 of Examples 1 to 19, 21 to 22 have better moisture and heat resistance compared to the luminescent particle 10 included in the ink composition 10 of Example 20. Furthermore, Ink Compositions 1 to 12 have a high PLQY retention rate during the curing of the ink composition and a high PLQY retention rate when irradiated with light for a long time as compared with Ink Compositions C1 to C4. From this, it can be understood that the luminescent particles 1 to 10 contained in Ink Compositions 1 to 12 are superior in stability and light resistance during curing as compared with the luminescent particles 11 to 14 contained in Ink Compositions C1 to C4.

[0199] From the above, it is clear that the luminescent particles 1 to 10, which are the luminescent particles of the present invention, are excellent in stability against water, light and heat and excellent in long-term storage stability. This is presumably because in each luminescent particle, the surface layer provided on the surface of the semiconductor nanocrystal contains a salt containing a monovalent cation, thereby suppressing the formation of surface defects in the semiconductor nanocrystal and suppressing the formation of surface defects due to the desorption of A sites caused by water, light or heat.

Industrial Applicability

[0200] The luminescent particles of the present invention are excellent in stability against water, light and heat, and also have little change in luminescent characteristics and excellent long-term storage stability. Therefore, they can be applied to various devices such as a light conversion layer, a color filter, a wavelength conversion film, and further a color display device and a liquid crystal display element.

Explanation of Reference Numerals

[0201] 100 Light-emitting element 200 EL light source unit 1 Lower substrate 2 Anode 3 Hole injection layer 4 Hole transport layer 5 Light-emitting layer 6 Electron transport layer 7 Electron injection layer 8 Cathode 9 Encapsulation layer 10 Filling layer 11 Protection layer 12 Light conversion layer 13 Upper substrate 14 EL layer 20 Pixel portion 20a First pixel portion 20b Second pixel portion 20c Third pixel portion 21a First light-scattering particle 21b Second light-scattering particle 21c Third light-scattering particle 22a First hardening component 22b Second hardening component 22c Third hardening component 90a First light-emitting particle 90b Second light-emitting particle 30 Light-shielding portion 40 Laminated structure 41 First substrate 42 Second substrate 43 Encapsulation layer 44 Wavelength conversion film 441 Light-scattering particle 442 Light-emitting particle 701 Capacitor 702 Driving transistor 703 Power supply line 705 Common electrode 706 Signal line 707 Scanning line 708 Switching transistor C1 Signal line driving circuit C2 Scanning line driving circuit C3 Control circuit PE Pixel electrode

Claims

1. A surface layer including a structure having a siloxane bond on the surface of a semiconductor nanocrystal composed of a metal halide, the surface layer containing a salt having a monovalent cation, wherein the semiconductor nanocrystal is a compound represented by the general formula A ａ M ｂ X ｃ and wherein A represents one or more cations selected from the group consisting of Cs, Rb, methylammonium, formamidinium, ammonium, 2-phenylethylammonium, pyrrolidinium, piperidinium, 1-butyl-1-methylpiperidinium, tetramethylammonium, tetraethylammonium, benzyltrimethylammonium, benzyltriethylammonium, guanidinium, imidazolium, pyridinium, and protonated thiourea, wherein M represents 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, wherein X represents one or more halide ions selected from the group consisting of F, Cl, Br, and I, a represents a positive number from 1 to 7, b represents a positive number from 1 to 4, and c represents a positive number from 1 to 16, the luminescent particles.

2. The luminescent particles according to claim 1, wherein the semiconductor nanocrystal has a perovskite crystal structure.

3. The luminescent particles according to claim 1, wherein the salt having a monovalent cation contains a halogen ion.

4. The luminescent particles according to claim 1, wherein the monovalent cation in the salt having a monovalent cation is an organic cation or a metal ion.

5. A surface layer including a structure having a siloxane bond on the surface of a semiconductor nanocrystal composed of a metal halide, the surface layer containing a salt having a monovalent cation, wherein the semiconductor nanocrystal is represented by the general formula A ａ M ｂ X ｃ and is composed of a compound represented by the formula wherein A represents one or more cations selected from the group consisting of Cs, Rb, methylammonium, formamidinium, ammonium, 2-phenylethylammonium, pyrrolidinium, piperidinium, 1-butyl-1-methylpiperidinium, tetramethylammonium, tetraethylammonium, benzyltrimethylammonium, benzyltriethylammonium, guanidinium, imidazolium, pyridinium, and protonated thiourea, wherein M represents 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, wherein X represents one or more halide ions selected from the group consisting of F, Cl, Br, and I, A method for producing luminescent particles, wherein a represents a positive number from 1 to 7, b represents a positive number from 1 to 4, and c represents a positive number from 1 to 16. A step of obtaining precursor particles having a surface layer containing a siloxane bond on the surface of the semiconductor nanocrystal by forming a siloxane bond on the surface of the semiconductor nanocrystal while forming the semiconductor nanocrystal from a solution containing a raw material compound capable of synthesizing the semiconductor nanocrystal, a silane compound A having a bonding group and a hydrolyzable silyl group capable of bonding to the surface of the semiconductor nanocrystal, and a solvent. A method for producing luminescent particles, comprising: a step of mixing the precursor particles, a polymer compound having a structural unit containing a basic group, and a silane compound B having a hydrolyzable silyl group and different from the silane compound A to obtain a mixture, and then adding an aqueous solution containing a salt containing a monovalent cation to the mixture to form a siloxane bond on the surface of the precursor particles, thereby obtaining luminescent particles having a surface layer containing the salt and the polymer compound on the surface of the precursor particles.

6. An ink composition containing the luminescent particles according to any one of Claims 1 to 4, a photopolymerizable compound, and a photoinitiator.

7. A light conversion layer containing a cured product of the ink composition according to Claim 6.

8. A color filter provided with the light conversion layer according to Claim 7.

9. A wavelength conversion film provided with the light conversion layer according to Claim 7.

Images