Quantum dots, electroluminescent elements, and ink compositions

Abstract

The problems that this invention aims to solve are to provide a highly stable quantum dot that can obtain high luminous efficiency when used as a light-emitting material in an electroluminescent device, and to provide an electroluminescent device that has high luminous efficiency and exhibits little decrease in brightness during long-term operation. Furthermore, it aims to provide an ink composition that exhibits high stability with little decrease in fluorescence quantum yield during long-term storage, and excellent film-forming properties. [Solution] A quantum dot containing semiconductor particles surface-treated with a surface treatment agent, wherein the surface treatment agent is represented by any of the general formulas (1) to (4).

Description

[Technical Field]

[0001] This invention relates to quantum dots, electroluminescent devices using the same, and ink compositions. [Background technology]

[0002] Electroluminescent (EL) devices are attracting attention as lightweight, thin, low-power, and highly flexible surface-emitting elements. Such electroluminescent devices possess many excellent features, including high brightness emission, fast response, wide viewing angle, thin and lightweight design, and high resolution, and are being considered for applications in flat panel displays and lighting. Among the various types of electroluminescent devices, quantum dots are attracting particular attention.

[0003] Quantum dots are tiny semiconductor particles on the nanoscale that exhibit behavior intermediate between atomic or molecular behavior and macroscopic solid (bulk) behavior. Nanoscale materials (semiconductor particles) in which charge carriers and excitons are confined in all three dimensions are called quantum dots, and as the size decreases, the effective band gap increases. That is, as the size of a quantum dot decreases, its absorption and emission shift to shorter wavelengths, in other words, from the red direction to the blue direction. Furthermore, by controlling the composition and size of the quantum dots in combination, a wide range of spectra from the infrared to the ultraviolet region can be obtained, and by further controlling the size distribution, spectra with a narrow full width at half maximum and excellent color purity can be obtained. Therefore, in recent years, quantum dot-type organic EL devices have been proposed that utilize these properties and use quantum dots made of semiconductor nanocrystals as the light-emitting material.

[0004] Quantum dots are generally surface-treated with ligands. Many ligands have a structure with adsorption groups at the ends of long-chain alkyl groups. While these ligands improve the chemical stability of the quantum dot surface, resulting in increased durability, and enhance dispersibility and dispersion stability in organic solvents and water, they are insulating and therefore do not perform adequately for applications in electroluminescent devices. For this reason, in recent years, ligands have been designed to improve the electrical properties of quantum dots, such as through charge injection (Patent Documents 1-2). However, the luminescence efficiency and stability when used as light-emitting materials in electroluminescent devices are insufficient, and there are also issues with film formation when used in ink compositions. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2004-315661 [Patent Document 2] Japanese Patent Publication No. 2008-214363 [Overview of the project] [Problems that the invention aims to solve]

[0006] The problems that this invention aims to solve are to provide a highly stable quantum dot that can obtain high luminous efficiency when used as a light-emitting material in an electroluminescent device, and to provide an electroluminescent device that has high luminous efficiency and exhibits little decrease in brightness during long-term operation. Furthermore, it aims to provide an ink composition that exhibits high stability with little decrease in fluorescence quantum yield during long-term storage, and excellent film-forming properties. [Means for solving the problem]

[0007] As a result of diligent research to solve the aforementioned problems, the inventors of the present invention have found that by using quantum dots containing semiconductor particles surface-treated with a surface treatment agent having a specific structure, the characteristics of the electroluminescent element can be improved, as well as the characteristics of the ink composition, leading to the present invention.

[0008] That is, the present invention relates to the following [1] to [3].

[0009] [1] A quantum dot containing semiconductor particles surface-treated with a surface treatment agent, wherein the surface treatment agent contains a compound represented by any of the following general formulas (1) to (4). [Chemical formula] [In general formula (1), X 1 is O, S, or NL 1 and L 1 is a hydrogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, or a substituted or unsubstituted monovalent aromatic heterocyclic group. Z 1 is O or S, R 1 ~R 6 is A 1 A 2 and A 1 is a direct bond, -CO-, -COO-, or -SO2-, A 2 is a hydrogen atom, a halogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic heterocyclic group, a cyano group, a nitro group, an amino group, a sulfanyl group, or a carboxy group. However, when A 2 is a hydrogen atom, a halogen atom, a cyano group, a nitro group, an amino group, a sulfanyl group, or a carboxy group, A 1 is a direct bond. At least one of R 1 ~R 6 has an amino group, a sulfanyl group, or a carboxy group.] [Chemical formula] [In general formula (2), X 2is O, S, or NL 1 And, L 1 This is a hydrogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, or a substituted or unsubstituted monovalent aromatic heterocyclic group. Z 2 is either O or S, R 7 ~R 12 is, A 1 A 2 And, A 1 These are direct bonds, -CO-, -COO-, or -SO2-, A 2 These are a hydrogen atom, a halogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic heterocyclic group, a cyano group, a nitro group, an amino group, a sulfanyl group, or a carboxyl group. However, A 2 When is a hydrogen atom, halogen atom, cyano group, nitro group, amino group, sulfanyl group, or carboxyl group, A 1 This is a direct bond. R 7 ~R 12 At least one of them has an amino group, a sulfanyl group, or a carboxyl group. However, general formula (2) is not applicable when it is expressed by general formula (1). [ka] [In general formula (3), X 3 is O, S, or NL 1 And, L 1 This is a hydrogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, or a substituted or unsubstituted monovalent aromatic heterocyclic group. Z 3 is either O or S, R 13 ~R 16 is, A 1 A2 And, A 1 These are direct bonds, -CO-, -COO-, or -SO2-, A 2 These are a hydrogen atom, a halogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic heterocyclic group, a cyano group, a nitro group, an amino group, a sulfanyl group, or a carboxyl group. However, A 2 When is a hydrogen atom, halogen atom, cyano group, nitro group, amino group, sulfanyl group, or carboxyl group, A 1 This is a direct bond. R 13 ~R 16 At least one of them has an amino group, a sulfanyl group, or a carboxyl group. However, general formula (3) is not used when it is expressed by general formula (1) or (2). [ka] [In general formula (4), X 4 is O, S, or NL 1 And, L 1 This is a hydrogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, or a substituted or unsubstituted monovalent aromatic heterocyclic group. Z 4 is either O or S, R 17 ~R 20 is, A 1 A 2 And, A 1 These are direct bonds, -CO-, -COO-, or -SO2-, A 2 These are a hydrogen atom, a halogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic heterocyclic group, a cyano group, a nitro group, an amino group, a sulfanyl group, or a carboxyl group. However, A 2 When is a hydrogen atom, halogen atom, cyano group, nitro group, amino group, sulfanyl group, or carboxyl group, A 1 This is a direct bond. R 17 ~R 20 At least one of these groups is an amino group, a sulfanyl group, or a carboxyl group. However, general formula (4) is excluded if it is represented by any of general formulas (1) to (3).

[0010] [2] An ink composition comprising the quantum dots and dispersion medium described in [1].

[0011] [3] An electroluminescent element having an anode, a light-emitting layer, and a cathode on a substrate, wherein the light-emitting layer includes the quantum dot described in [1]. [Effects of the Invention]

[0012] This invention makes it possible to provide highly stable quantum dots that can be used as light-emitting materials in electroluminescent devices to obtain high luminous efficiency. Furthermore, it makes it possible to provide electroluminescent devices with high luminous efficiency and minimal brightness degradation during long-term operation. In addition, it makes it possible to provide an ink composition with high stability, minimal degradation of fluorescence quantum yield during long-term storage, and excellent film-forming properties. [Modes for carrying out the invention]

[0013] <Quantum dots> The quantum dots of the present invention are characterized by containing semiconductor particles surface-treated with a surface treatment agent containing a compound represented by any of the following general formulas (1) to (4). The present invention will be described in detail below.

[0014] <Semiconductor particles> The materials used for semiconductor particles include elemental elements of Group IV of the periodic table such as carbon (C) (amorphous carbon, graphite, graphene, carbon nanotubes, etc.), silicon (Si), germanium (Ge), and tin (Sn); elemental elements of Group V of the periodic table such as phosphorus (P) (black phosphorus); elemental elements of Group VI of the periodic table such as selenium (Se) and tellurium (Te); tin(IV) oxide, boron nitride (BN), boron phosphide (BP), boron arsenide (BAs), aluminum nitride (AlN), aluminum phosphide (AlP), aluminum arsenide (AlAs), and aluminum antimonide (AlSb). Compounds of Group III and Group V elements of the periodic table, such as gallium nitride (GaN), gallium phosphide (GaP), gallium arsenide (GaAs), gallium antimonide (GaSb), indium nitride (InN), indium phosphide (InP), indium arsenide (InAs), and indium antimonide (InSb), such as aluminum sulfide (Al2S3), aluminum selenide (Al2Se3), gallium sulfide (Ga2S3), gallium selenide (GaSe, Ga2Se3), gallium telluride (GaTe, Ga2Te3), and indium oxide (In2O 3)Compounds of Group III and Group VI elements of the periodic table, such as indium sulfide (In2S3, InS), indium selenide (In2Se3), and indium telluride (In2Te3); zinc oxide (ZnO), zinc sulfide (ZnS), zinc selenide (ZnSe), zinc telluride (ZnTe); cadmium oxide (CdO), cadmium sulfide (CdS), cadmium selenide (CdSe), cadmium telluride (CdTe); mercury sulfide (HgS), mercury selenide (HgSe), mercury telluride (HgTe) Examples include compounds of Group II and Group VI elements of the periodic table, such as e), compounds of Group I and Group VI elements of the periodic table, such as copper(I) oxide (Cu2O), compounds of Group I and Group VII elements of the periodic table, such as copper(I) chloride (CuCl), copper(I) bromide (CuBr), copper(I) iodide (CuI), silver chloride (AgCl), silver bromide (AgBr), and Group I-III-VI2 chalcopylite compound semiconductors such as AgInS2 and CuInS2. Two or more of these may be used in combination as needed. These semiconductors may contain elements other than the constituent elements. For example, taking Group III-V as an example, alloy systems such as InGaP and InGaN may be used. Semiconductor particles doped with rare earth elements or transition metal elements are also used in the above materials. Examples include ZnS:Mn, ZnS:Tb, ZnS:Ce, and LaPO4:Ce.

[0015] Among these, alloy systems such as silicon (Si), germanium (Ge), gallium nitride (GaN), gallium phosphide (GaP), gallium arsenide (GaAs), indium nitride (InN), indium phosphide (InP), indium arsenide (InAs), gallium selenide (GaSe, Ga2Se3), indium sulfide (In2S3, InS), zinc oxide (ZnO), zinc sulfide (ZnS), zinc selenide (ZnSe), zinc telluride (ZnTe), cadmium oxide (CdO), cadmium sulfide (CdS), cadmium selenide (CdSe), cadmium telluride (CdTe), InGaP, and InGaN are preferably used, and indium phosphide (InP), cadmium selenide (CdSe), zinc sulfide (ZnS), and zinc selenide (ZnSe) are particularly preferred. In particular, it is preferable to use InP as the core and ZnS and / or ZnSe as the shell.

[0016] Furthermore, perovskite crystals can also be suitably used as the material for semiconductor particles. Perovskite crystals have a composition represented by the following formula (I) and possess a three-dimensional crystal structure. Equation (I): AQX3 [In formula (I), A is a monovalent cation of at least one amine compound selected from the group consisting of methylammonium (CH3NH2) and formamidinium (NH2CHNH), or a monovalent cation of at least one alkali metal element selected from the group consisting of rubidium (Rb), cesium (Cs), and francium (Fr); Q is a divalent cation of at least one metal element selected from the group consisting of lead (Pb) and tin (Sn); and X is a monovalent anion of at least one halogen element selected from the group consisting of iodine (I), bromine (Br), and chlorine (Cl).]

[0017] The semiconductor particles preferably have a core-shell structure. Core-shell semiconductor particles have a structure in which the core structure is coated with a material having a different composition from the material forming the core. By selecting a semiconductor with a large band gap for the shell, excitons (electron-hole pairs) generated by photoexcitation are confined within the core. As a result, the probability of non-radiative transitions at the particle surface is reduced, improving the quantum yield of emission and the stability of fluorescence properties. Furthermore, there may be multiple layers of shell. In addition, the boundary between the core and the shell, and the boundary between one shell and another, may be clear, or it may be a gradient structure where the shells are gradually joined by providing a concentration gradient. Furthermore, the shell may cover only a part of the core, or it may cover the entire core.

[0018] The average particle size of the semiconductor particles, including the core and shell, is typically 0.5 nm to 100 nm, preferably 1 to 50 nm, and more preferably 1 to 15 nm.

[0019] The average particle size referred to here is the value obtained by observing semiconductor particles with a transmission electron microscope, measuring the size of 30 randomly selected particles, and adopting the average value. In this case, since the semiconductor particles are accompanied by the surface treatment agent described later, a scanning transmission electron microscope equipped with energy-dispersive X-ray analysis is used to identify the semiconductor material portion, and then the particle size is measured by utilizing the fact that the semiconductor particle portion is imaged as darker in the transmission electron microscope image due to the difference in electron density compared to the surface treatment agent described later. The shape of the semiconductor particles is not limited to spheres; they may be rod-shaped, disc-shaped, or other shapes.

[0020] <Surface treatment agent> The surface treatment agent used in the present invention (hereinafter sometimes abbreviated as "treatment agent") contains a compound represented by any of the following general formulas (1) to (4).

[0021] The above general formula (1) will be explained.

[0022] In general formula (1), X 1 is O, S, or NL 1 And, L1 This is a hydrogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, or a substituted or unsubstituted monovalent aromatic heterocyclic group. Z 1 is either O or S, R 1 ~R 6 is, A 1 A 2 And, A 1 These are direct bonds, -CO-, -COO-, or -SO2-, A 2 These are a hydrogen atom, a halogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic heterocyclic group, a cyano group, a nitro group, an amino group, a sulfanyl group, or a carboxyl group. However, A 2 When is a hydrogen atom, halogen atom, cyano group, nitro group, amino group, sulfanyl group, or carboxyl group, A 1 This is a direct bond. R 1 ~R 6 At least one of them has an amino group, a sulfanyl group, or a carboxyl group.

[0023] L 1 and A 2 The monovalent aliphatic hydrocarbon group is preferably a monovalent aliphatic hydrocarbon group having 1 to 18 carbon atoms, such as alkyl groups, alkenyl groups, alkynyl groups, and cycloalkyl groups. The monovalent aliphatic hydrocarbon group may be linear or branched.

[0024] Examples of alkyl groups here include alkyl groups having 1 to 18 carbon atoms, such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, isopentyl group, hexyl group, heptyl group, octyl group, decyl group, dodecyl group, pentadecyl group, and octadecyl group.

[0025] Examples of alkenyl groups include vinyl groups, 1-propenyl groups, 2-propenyl groups, isopropenyl groups, 1-butenyl groups, 2-butenyl groups, 3-butenyl groups, 1-octenyl groups, 1-decenyl groups, and 1-octadecenyl groups, which are alkenyl groups having 2 to 18 carbon atoms.

[0026] Examples of alkynyl groups include ethylenyl, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, 1-octynyl, 1-decynyl, and 1-octadecynyl groups, which have 2 to 18 carbon atoms.

[0027] Examples of cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclooctadecyl, and 2-indeno groups, which are cycloalkyl groups with 3 to 18 carbon atoms.

[0028] Furthermore, L 1 and A 2 Examples of monovalent aromatic hydrocarbon groups include monovalent monocyclic, fused-ring, and ring-aggregated aromatic hydrocarbon groups, and it is preferable that the monovalent aromatic hydrocarbon group has 6 to 18 carbon atoms.

[0029] Examples of monovalent monocyclic aromatic hydrocarbon groups include phenyl groups, o-tolyl groups, m-tolyl groups, p-tolyl groups, 2,4-xylyl groups, p-cumenyl groups, mesityl groups, and other monovalent monocyclic aromatic hydrocarbon groups having 6 to 18 carbon atoms.

[0030] Furthermore, examples of monovalent condensed ring aromatic hydrocarbon groups include monovalent condensed ring aromatic hydrocarbon groups having 10 to 18 carbon atoms, such as 1-naphthyl group, 2-naphthyl group, 1-anthryl group, 2-anthryl group, 5-anthryl group, 1-phenanthuryl group, 9-phenanthuryl group, 1-acenaphthyl group, 2-azlenyl group, 1-pyrenyl group, and 2-triphenylell group.

[0031] Furthermore, examples of monovalent ring-aggregated aromatic hydrocarbon groups include monovalent ring-aggregated aromatic hydrocarbon groups having 12 to 18 carbon atoms, such as o-biphenylyl groups, m-biphenylyl groups, and p-biphenylyl groups.

[0032] Furthermore, L 1 and A 2 The monovalent aromatic heterocyclic groups include triazolyl, 3-oxadiazolyl, 2-furanyl, 3-furanyl, 2-furyl, 3-furyl, 2-thienyl, 3-thienyl, 1-pyrrolyl, 2-pyrrolyl, 3-pyrrolyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, 2-pyradyl, 2-oxazolyl, 3-isoxazolyl, 2-thiazolyl, 3-isothiazolyl, 2-imidazolyl, and 3-pyradyl groups. Examples include monovalent aromatic heterocyclic groups having 2 to 18 carbon atoms, such as zolyl, 2-quinolyl, 3-quinolyl, 4-quinolyl, 5-quinolyl, 6-quinolyl, 7-quinolyl, 8-quinolyl, 1-isoquinolyl, 2-quinoxalinyl, 2-benzofuryl, 2-benzothienyl, N-indolyl, N-carbazolyl, N-acridinyl, 2-thiophenyl, 3-thiophenyl, bipyridyl, and phenantrolyl groups.

[0033] L 1 and A 2 The monovalent aliphatic hydrocarbon group, monovalent aromatic hydrocarbon group, and monovalent aromatic heterocyclic group may further have substituents. Examples of substituents that may be present include halogen atoms, substituted or unsubstituted monovalent aliphatic hydrocarbon groups, substituted or unsubstituted monovalent aromatic hydrocarbon groups, substituted or unsubstituted monovalent aromatic heterocyclic groups, cyano groups, nitro groups, amino groups, sulfanyl groups, or carboxyl groups. For details on these substituents, refer to the above-mentioned explanations of monovalent aliphatic hydrocarbon groups, monovalent aromatic hydrocarbon groups, and monovalent aromatic heterocyclic groups.

[0034] A 2 Examples of halogen atoms include fluorine, chlorine, bromine, and iodine.

[0035] The general formula (2) will be described below.

[0036] In the general formula (2), X 2 is O, S, or NL 1 and L 1 is a hydrogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, or a substituted or unsubstituted monovalent aromatic heterocyclic group. Z 2 is O or S, and R 7 ~R 12 is A 1 A 2 and A 1 is a direct bond, -CO-, -COO-, or -SO2-. A 2 is a hydrogen atom, a halogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic heterocyclic group, a cyano group, a nitro group, an amino group, a sulfanyl group, or a carboxy group. However, when A 2 is a hydrogen atom, a halogen atom, a cyano group, a nitro group, an amino group, a sulfanyl group, or a carboxy group, A 1 is a direct bond. At least one of R 7 ~R 12 has an amino group, a sulfanyl group, or a carboxy group. However, the general formula (2) excludes the case represented by the general formula (1).

[0037] L 1 and A 2 The substituted or unsubstituted monovalent aliphatic hydrocarbon groups, substituted or unsubstituted monovalent aromatic hydrocarbon groups, substituted or unsubstituted monovalent aromatic heterocyclic groups, and the halogen atoms of A 2 For, the description of the above general formula (1) can be cited.

[0038] The above general formula (3) will be explained.

[0039] In general formula (3), X 3 is O, S, or NL 1 And, L 1 This is a hydrogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, or a substituted or unsubstituted monovalent aromatic heterocyclic group. Z 3 is either O or S, R 13 ~R 16 is, A 1 A 2 And, A 1 These are direct bonds, -CO-, -COO-, or -SO2-, A 2 These are a hydrogen atom, a halogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic heterocyclic group, a cyano group, a nitro group, an amino group, a sulfanyl group, or a carboxyl group. However, A 2 When is a hydrogen atom, halogen atom, cyano group, nitro group, amino group, sulfanyl group, or carboxyl group, A 1 This is a direct bond. R 13 ~R 16 At least one of them has an amino group, a sulfanyl group, or a carboxyl group. However, general formula (3) is not used when it is expressed by general formula (1) or (2).

[0040] L 1 and A 2 A substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic heterocyclic group, and A 2 The explanation for the halogen atom described above for general formula (1) can be applied to this.

[0041] The above general formula (4) will be explained.

[0042] In general formula (4), X 4 is O, S, or NL 1 And, L 1 This is a hydrogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, or a substituted or unsubstituted monovalent aromatic heterocyclic group. Z 4 is either O or S, R 17 ~R 20 is, A 1 A 2 And, A 1 These are direct bonds, -CO-, -COO-, or -SO2-, A 2 These are a hydrogen atom, a halogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic heterocyclic group, a cyano group, a nitro group, an amino group, a sulfanyl group, or a carboxyl group. However, A 2 When is a hydrogen atom, halogen atom, cyano group, nitro group, amino group, sulfanyl group, or carboxyl group, A 1 This is a direct bond. R 17 ~R 20 At least one of these groups is an amino group, a sulfanyl group, or a carboxyl group. However, general formula (4) is excluded if it is represented by any of general formulas (1) to (3).

[0043] L 1 and A 2 A substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic heterocyclic group, and A 2 The explanation for the halogen atom described above for general formula (1) can be applied to this.

[0044] Compounds of general formulas (1) to (4) are preferably equipped with an electron-withdrawing group in their structure, from the viewpoint of suppressing a decrease in brightness during long-term operation. Examples of electron-withdrawing groups include halogen atoms, perfluoroalkyl groups, cyano groups, and A 1 -A when -CO-, -COO-, or -SO2- 1 -A 2 These are some examples. A perfluoroalkyl group is formed by replacing all hydrogen atoms in an alkyl chain with fluorine atoms, and is represented as -(CF2)n-CF3 (where n is any integer in the range of 0 to 18), where n is preferably in the range of 0 to 18. Examples of perfluoroalkyl groups include trifluoromethyl group, pentafluoroethyl group, pentadecafluorooctyl group, heptatriacontafluorooctadecyl group, and the like. Fluorine atoms, trifluoromethyl groups, and cyano groups are particularly preferred as electron-withdrawing groups.

[0045] Compounds of general formulas (1) to (4) are A 1 A is a direct bond, 2 -A is an amino group, a sulfanyl group, or a carboxyl group. 1 -A 2 Having this feature is thought to result in excellent carrier transfer between the ligand and the quantum dot, which is preferable from the viewpoint of luminescence efficiency.

[0046] From the viewpoint of ink stability and film-forming properties, it is preferable that the number of amino groups, sulfanyl groups, or carboxyl groups in the compounds of general formulas (1) to (4) is one.

[0047] Specific examples of treatment agents are shown below, but the application is not limited to these. Furthermore, in the structural formulas below, if cis and trans geometric isomers exist, the compound may be cis, trans, or a mixture of cis and trans isomers. The same applies to syn-anti geometric isomerism.

[0048] [ka]

[0049] [ka]

[0050] [ka]

[0051] [ka]

[0052] [ka]

[0053] <Ink composition> The quantum dot-containing ink composition of the present invention contains the above-mentioned quantum dots and a dispersion medium. The dispersion medium is used to disperse the quantum dots and facilitate the coating of the quantum dots of the present invention onto a substrate such as a glass substrate so that the dry film thickness is a desired thickness.

[0054] (dispersion medium) The dispersion medium is not particularly limited and includes, for example, 1,2,3-trichloropropane, 1,3-butylene glycol, 1,3-butylene glycol diacetate, 1,4-dioxane, 2-heptanone, 2-methyl-1,3-propanediol, 3,5,5-trimethyl-2-cyclohexen-1-one, 3,3,5-trimethylcyclohexanone, 3-ethoxypropionate ethyl, 3-methyl-1,3-butanediol, 3-methoxy-3-methyl-1-butanol, 3-methoxy-3-methylbutyl acetate, 3-methoxybutanol, 3-methoxy Sibutylacetate, 4-heptanone, m-xylene, m-diethylbenzene, m-dichlorobenzene, N,N-dimethylacetamide, N,N-dimethylformamide, n-butyl alcohol, n-butylbenzene, n-propylacetate, N-methylpyrrolidone, toluene, octane, nonane, hexane, o-xylene, o-chlorotoluene, o-diethylbenzene, o-dichlorobenzene, p-chlorotoluene, p-diethylbenzene, sec-butylbenzene, tert-butylbenzene, γ-butyrolactone, water, methanol, ethanol Isopropyl alcohol, tertiary butanol, isobutyl alcohol, isophorone, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monotertiary butyl ether, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, ethylene glycol monopropyl ether, ethylene glycol monohexyl ether, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, diisobutyl ketone, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether, cyclohexanol, cyclohexanol acetate, cyclohexanone,Examples include dipropylene glycol dimethyl ether, dipropylene glycol methyl ether acetate, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monomethyl ether, diacetone alcohol, triacetin, tripropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, propylene glycol diacetate, propylene glycol phenyl ether, propylene glycol monoethyl ether, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether, propylene glycol monopropyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether propionate, benzyl alcohol, methyl isobutyl ketone, methylcyclohexanol, n-amyl acetate, n-butyl acetate, isoamyl acetate, isobutyl acetate, propyl acetate, and dibasic acid esters. These dispersion media can be used individually or mixed in any ratio of two or more as needed.

[0055] The viscosity of the ink composition of the present invention may be adjusted using a dispersion medium, resin, polymerizable monomer, etc. When using the ink composition of the present invention as an inkjet ink, it is preferable to adjust the viscosity at 25°C to 3 to 50 mPa·s. In addition, resins, crosslinking agents, polymerizable monomers, photosensitive substances, heat-sensitive substances, etc., can be added to the ink composition depending on the required physical properties of the printed material.

[0056] <Electric field light-emitting element> The quantum dot-containing layer of the present invention can be used as a light-emitting layer in an electroluminescent device. The electroluminescent device has a substrate, a cathode and an anode provided on the substrate, and a light-emitting layer between the two electrodes. Furthermore, due to the nature of light-emitting devices, at least one of the electrodes, the anode and the cathode, is transparent.

[0057] A preferred configuration for stacking the light-emitting element is one in which a hole transport layer, an emissive layer, and an electron transport layer are stacked in that order from the anode side. Furthermore, a charge blocking layer or the like may be provided between the hole transport layer and the emissive layer, or between the emissive layer and the electron transport layer. A hole injection layer may be provided between the anode and the hole transport layer, and an electron injection layer may be provided between the cathode and the electron transport layer. In addition, the emissive layer may be just one layer, or it may be divided into a first emissive layer, a second emissive layer, a third emissive layer, etc. Furthermore, each layer may be divided into multiple secondary layers. Typical element configurations for multilayer electroluminescent devices include: (1) anode / hole injection layer / light-emitting layer / cathode, (2) anode / hole injection layer / hole transport layer / light-emitting layer / cathode, (3) anode / hole injection layer / light-emitting layer / electron injection layer / cathode, (4) anode / hole injection layer / hole transport layer / light-emitting layer / electron injection layer / cathode, (5) anode / hole injection layer / light-emitting layer / hole blocking layer / electron injection layer / cathode, and (6) anode / hole injection layer / hole transport layer / light-emitting layer / hole blocking layer / electron Possible device configurations include stacking multiple layers such as (7) injection layer / cathode, (8) anode / emissive layer / hole blocking layer / electron injection layer / cathode, (9) anode / hole injection layer / hole transport layer / interlayer layer / emissive layer / cathode, (10) anode / hole injection layer / interlayer layer / emissive layer / electron injection layer / cathode, and (11) anode / hole injection layer / hole transport layer / interlayer layer / emissive layer / electron injection layer / cathode.

[0058] As a substrate for forming an electroluminescent element, for example, a substrate used in a known organic EL element can be used. The substrate may be a resin film or a gas barrier film, and gas barrier films described in Japanese Patent Publication No. 2004-136466, Japanese Patent Publication No. 2004-148566, Japanese Patent Publication No. 2005-246716, Japanese Patent Publication No. 2005-262529, etc., can also be preferably used. The substrate thickness is not particularly specified, but is preferably 30 μm to 700 μm, more preferably 40 μm to 200 μm, and even more preferably 50 μm to 150 μm. Furthermore, in all cases, the haze is preferably 3% or less, more preferably 2% or less, and even more preferably 1% or less, and the total light transmittance is preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more.

[0059] <Anode> The anode typically only needs to function as an electrode that supplies holes to an organic or inorganic compound layer. There are no particular restrictions on its shape, structure, size, etc., and it can be appropriately selected from known electrode materials depending on the application and purpose of the light-emitting element. As mentioned above, the anode is usually provided as a transparent anode. Transparent anodes are described in detail in "New Developments in Transparent Electrode Films" supervised by Yutaka Sawada, published by CMC (1999). When using a plastic substrate with low heat resistance as the substrate, a transparent anode made of ITO, IZO, or IGZO and deposited at a low temperature of 150°C or below is preferred.

[0060] <Cathode> The cathode typically only needs to function as an electrode that injects electrons into an organic or inorganic compound layer. There are no particular restrictions on its shape, structure, size, etc., and it can be appropriately selected from known electrode materials depending on the application and purpose of the light-emitting device. Materials that constitute the cathode include, for example, metals, alloys, metal oxides, electrically conductive compounds, and mixtures thereof. Specific examples include Group 2 metals (e.g., Mg, Ca), gold, silver, lead, aluminum, lithium-aluminum alloys, magnesium-silver alloys, indium, ytterbium, and other rare earth metals. While these may be used individually, two or more can be suitably used in combination to achieve both stability and electron injection properties.

[0061] Among these, materials mainly composed of aluminum are preferred for the cathode. Materials mainly composed of aluminum refer to aluminum alone, or alloys of aluminum with 0.01 to 100% by mass of an alkali metal or group 2 metal (for example, lithium-aluminum alloy, magnesium-aluminum alloy, etc.). The materials for the cathode are described in detail in Japanese Patent Publication No. 2-15595 and Japanese Patent Publication No. 5-121172. In addition, a dielectric layer made of alkali metal or group 2 metal fluoride, oxide, etc., with a thickness of 0.1 to 5 nm may be inserted between the cathode and the organic compound or inorganic compound layer. This dielectric layer can also be considered a type of electron injection layer.

[0062] The thickness of the cathode can be appropriately selected depending on the material constituting the cathode and cannot be specified in general terms, but it is usually around 10 nm to 5 μm, with 50 nm to 1 μm being preferred. The cathode may be transparent or opaque. A transparent cathode can be formed by depositing a thin film of cathode material to a thickness of 1 to 10 nm and then laminating a transparent conductive material such as ITO, IZO, or IGZO.

[0063] <Luminous layer> The light-emitting layer is a layer that, when an electric field is applied, receives holes from the anode, hole injection layer, or hole transport layer, and electrons from the cathode, electron injection layer, or electron transport layer, providing a field for the recombination of holes and electrons and causing light emission. The light-emitting layer may consist only of the quantum dots of the present invention, or it may be a mixed layer of quantum dots and a host material. The light-emitting material may further contain a fluorescent material and / or a phosphorescent material, and there may be one or more dopants. The host material is preferably a charge transport material. There may be one or more host materials, for example, a mixture of an electron transport host material and a hole transport host material. Furthermore, the light-emitting layer may contain a material that does not have charge transport properties and does not emit light. Also, the light-emitting layer may consist of one layer or two or more layers, and each layer may emit light in a different color.

[0064] Examples of fluorescent materials include, for example, benzoxazole derivatives, benzimidazole derivatives, benzothiazole derivatives, styrylbenzene derivatives, polyphenyl derivatives, diphenylbutadiene derivatives, tetraphenylbutadiene derivatives, naphthalimide derivatives, coumarin derivatives, condensed aromatic compounds, perinone derivatives, oxadiazole derivatives, oxazine derivatives, aldazine derivatives, pyrazin derivatives, cyclopentadiene derivatives, bisstyrylanthracene derivatives, quinacridone derivatives, pyrrolopyridine derivatives, thiadiazolopyridine derivatives, cyclopentadiene derivatives, styrylamine derivatives, diketopyrrolopyrrole derivatives, aromatic dimethylidine compounds, various metal complexes such as metal complexes of 8-quinolinol derivatives and pyromethene derivatives, polymer compounds such as polythiophene, polyphenylene, and polyphenylene vinylene, and compounds such as organosilane derivatives.

[0065] Examples of phosphorescent materials include complexes containing transition metal atoms or lanthanide atoms. The transition metal atoms are not particularly limited, but preferably include ruthenium, rhodium, palladium, tungsten, rhenium, osmium, iridium, and platinum, and more preferably rhenium, iridium, and platinum. Examples of the lanthanide atoms include lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutesium. Among these lanthanide atoms, neodymium, europium, and gadolinium are preferred.

[0066] Examples of ligands for complexes include those described in G. Wilkinson et al., "Comprehensive Coordination Chemistry," published by Pergamon Press in 1987; H. Yersin, "Photochemistry and Photophysics of Coordination Compounds," published by Springer-Verlag in 1987; and Akio Yamamoto, "Organometallic Chemistry - Fundamentals and Applications," published by Shokabo in 1982.

[0067] Furthermore, examples of host materials contained in the light-emitting layer include those having a carbazole skeleton, a diarylamine skeleton, a pyridine skeleton, a pyrazine skeleton, a triazine skeleton, and an arylsilane skeleton, as well as materials exemplified in the sections on hole injection layer, hole transport layer, electron injection layer, and electron transport layer described later.

[0068] <Hole injection layer, hole transport layer> The hole injection layer and the hole transport layer are layers that have the function of receiving holes from the anode or the anode side and transporting them to the cathode side. As long as they have the above-mentioned function, they may be organic compounds or inorganic compounds, and may be low-molecular-weight compounds, high-molecular-weight compounds or metal oxides. The hole injection layer and hole transport layer preferably contain, specifically, low molecular weight compounds such as carbazole derivatives, triphenylamine derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, aminosubstituted chalcone derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic tertiary amine compounds, styrylamine compounds, aromatic dimethylidine compounds, porphyrin compounds, phthalocyanine compounds, and organosilane derivatives; carbon compounds such as carbon and fullerenes; inorganic compounds consisting of metal oxides such as vanadium pentoxide and molybdenum trioxide; and high molecular weight compounds such as polyvinylcarbazole, polypyrrole, and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) (PEDOT-PSS).

[0069] <Electron injection layer, electron transport layer> The electron injection layer and electron transport layer are layers that have the function of receiving electrons from the cathode or the cathode side and transporting them to the anode side. Specifically, the electron injection layer and electron transport layer are preferably layers that contain triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, fluorenone derivatives, anthraquinodimethane derivatives, anthrone derivatives, diphenylquinone derivatives, thiopyrandioxide derivatives, carbodiimide derivatives, fluorenylidene methane derivatives, distylylpyrazine derivatives, aromatic ring tetracarboxylic anhydrides such as naphthalene and perylene, phthalocyanine derivatives, metal complexes of 8-quinolinol derivatives and metal phthalocyanines, various metal complexes represented by metal complexes with benzoxazole and benzothiazole as ligands, low molecular weight compounds such as organosilane derivatives, metal oxides such as zinc oxide (ZnO) and titanium dioxide (TiO2), and alkali metal-doped organic or inorganic compounds, with magnesium-doped zinc oxide (ZnMgO) being particularly preferred.

[0070] <Hole Blocking Layer> A hole blocking layer is a layer that prevents holes transported from the anode to the light-emitting layer from passing through to the cathode. In this invention, a hole blocking layer can be provided as an organic compound layer adjacent to the light-emitting layer on the cathode side. Alternatively, an electron transport layer and / or an electron injection layer may also function as a hole blocking layer. Examples of organic compounds that constitute the hole blocking layer include aluminum complexes such as BAlq, triazole derivatives, and phenanthroline derivatives such as BCP. Furthermore, a layer that prevents electrons transported from the cathode to the light-emitting layer from passing through to the anode can be provided adjacent to the light-emitting layer on the anode side. The hole transport layer and / or hole injection layer may also perform this function. [Examples]

[0071] The present invention will be described in more detail below with reference to examples, but these examples do not limit the technical scope of the present invention in any way. In the examples, "parts" and "%" refer to "parts by mass" and "mass%", respectively, unless otherwise specified.

[0072] <Manufacturing of quantum dot-containing compositions> [Synthesis Example 1] An additive solution was prepared by heating and dissolving 0.55 parts of anhydrous zinc acetate, 7.0 parts of dodecanethiol (treatment agent R1), and 5.0 parts of oleylamine. Separately, 0.22 parts of indium chloride and 8.25 parts of octylamine were placed in a reaction vessel and heated to 165°C while bubbling with nitrogen. After the indium chloride dissolved, 0.86 parts of diethylaminophosphine were added to the reaction vessel and the mixture was maintained at 165°C for 20 minutes. The mixture was then cooled to 40°C. Next, the above additive solution was added to the reaction vessel and heated at 240°C for 2 hours, then allowed to cool to 25°C. After cooling, the mixture was purified by reprecipitation using hexane and ethanol to obtain quantum dots EX1, which are core-shell semiconductor particles with an InP core and a ZnS shell, surface-treated with dodecanethiol.

[0073] [Synthesis Example 2] 2.0 mL of oleic acid and 10 mL of 1-octadecene were added to a flask, and the mixture was heated and stirred under reduced pressure at 100°C for 1 hour to degass it. Then, nitrogen was purged into the flask and the mixture was heated to 270°C. Once the solution temperature stabilized, 0.2 mL of a tellurium / trioctylphosphine solution, prepared separately by dissolving trioctylphosphine with tellurium to a concentration of 0.3 M, and 0.8 mL of a selenium / trioctylphosphine solution, prepared by dissolving trioctylphosphine with selenium to a concentration of 0.3 M, were added to the flask. Furthermore, 0.3 mmol of diethylzinc solution was added, and the mixture was maintained at 270°C for 30 minutes to synthesize ZnTeSe core semiconductor particles. In a separate flask, 3.0 g (4.74 mmol) of zinc stearate and 15 mL of octadecene were added, heated to 100°C to dissolve, and then stirred under vacuum for 1 hour to degas and prepare a zinc precursor solution. 10 mL (3.16 mmol) of the above zinc precursor solution and 2.4 mL (0.3 mmol) of a 1.25 M selenium / trioctylphosphine solution prepared in yet another flask were simultaneously added to the reaction solution at 270°C in the flask in which the ZnTeSe core semiconductor particles were synthesized, and this reaction solution was stirred for 30 minutes. Next, 4.0 mL of trioctylphosphine was added to 0.16 g (5.0 mmol) of sulfur and heated to 150°C to dissolve, thereby preparing a 1.25 M sulfur / trioctylphosphine solution. 1.0 mL of this solution was added to the reaction solution and stirred for 1 hour. Then, 0.22 g (1.1 mmol) of zinc acetate was added to the reaction solution and dissolved under reduced pressure by heating to 100°C and stirring. The flask was again purged with nitrogen and the temperature was raised to 230°C. 0.48 mL (2 mmol) of dodecanethiol was added and the mixture was held for 1 hour. The resulting reaction solution was cooled to 25°C. After cooling, the solution was purified by reprecipitation using toluene and ethanol to obtain quantum dots EX2, which are core-shell type semiconductor particles consisting of a ZnTeSe core and a ZnSe / ZnS bilayer shell, surface-treated with dodecanethiol.

[0074] [Synthesis Example 3] 0.033 g (0.20 mmol) of silver(I) acetate, 0.058 g (0.20 mmol) of indium acetate, 0.65 mL (2.7 mmol) of 1-dodecanethiol, and 4.0 ml of oleylamine were added to a flask. The mixture was heated and stirred under reduced pressure at 100°C for 1 hour to degass it. Then, nitrogen was purged into the flask, and the mixture was heated to 200°C and held for 20 minutes. Subsequently, the flask was heated to 230°C, and 1.0 mL of a separately prepared 1.25 M sulfur / trioctylphosphine solution was added to the reaction solution and stirred for 1 hour. Finally, 0.066 g (0.36 mmol) of zinc acetate, 0.24 ml (0.76 mmol) of oleic acid, and 0.15 ml of oleylamine were added to the flask and the mixture was heated and stirred at 230°C for 1 hour. The resulting solution was cooled to 25°C. After cooling, the material was purified by reprecipitation using True and ethanol to obtain quantum dots EX3, which are core-shell type semiconductor particles with an AgInS2 core and a ZnS shell, surface-treated with dodecanethiol.

[0075] [Example 1] (Quantum dots and ink compositions) Quantum dots EX1 obtained in Synthesis Example 1 were diluted to a solid content concentration of 1% using toluene. The same amount of toluene solution of treatment agent 1 shown in Table 1, with a concentration of 5%, was added and stirred for 12 hours. Purification was performed by reprecipitation using toluene and ethanol. Using mesitylene, the solid content concentration was adjusted to 10%, and ink composition 1 was obtained containing quantum dots, which were core-shell type semiconductor particles with an InP core and a ZnS shell, surface-treated with treatment agent 1. The average particle size of the semiconductor particles was measured for quantum dots separated from the obtained ink composition 1. By using a scanning transmission electron microscope equipped with energy-dispersive X-ray spectroscopy, the semiconductor particle portion was identified, and the particle size of the semiconductor particles was measured by utilizing the fact that the semiconductor particle portion is imaged darker in the transmission electron microscope image compared to the surface treatment agent due to the difference in electron density. Specifically, the short axis diameter and long axis diameter of the semiconductor particle were measured, and the average value of the short axis diameter and long axis diameter was taken as the particle size of that semiconductor particle. The average value was calculated for 30 randomly selected semiconductor particles and was taken as the average particle size of the semiconductor particles. The average particle size of the semiconductor particles contained in the quantum dot EX1 was 13 nm.

[0076] [Examples 2-138, Comparative Examples 1-3] Except for changing treatment agent 1 to treatment agents 2 to 138 and R1 to R3 shown in Tables 1 to 21, ink compositions 2 to 138 and R1 to R3 containing quantum dots in which core-shell type semiconductor particles with an InP core and a ZnS shell were surface-treated with the treatment agents were obtained in the same manner as in Example 1. Ink compositions 2 to 138 are the ink compositions of the present invention, and ink compositions R1 to R3 are ink compositions that are not the ink compositions of the present invention.

[0077] [Example 139] An ink composition 139 was obtained in the same manner as in Example 1, except that the quantum dot EX1 obtained in Synthesis Example 1 was replaced with quantum dot EX2 obtained in Synthesis Example 2, and the process was the same as in Example 1, with core-shell type semiconductor particles having a ZnTeSe core and a ZnSe / ZnS two-layer shell being surface-treated with treatment agent 1.

[0078] [Example 140] An ink composition 140 containing quantum dots, in which core-shell type semiconductor particles having a ZnTeSe core and a ZnSe / ZnS two-layer shell are surface-treated with treatment agent 25, was obtained in the same manner as in Example 1, except that quantum dot EX1 obtained in Synthesis Example 1 was replaced with quantum dot EX2 obtained in Synthesis Example 2, and treatment agent 1 was replaced with treatment agent 25.

[0079] [Example 141] An ink composition 141 containing quantum dots, in which core-shell type semiconductor particles having a ZnTeSe core and a ZnSe / ZnS two-layer shell are surface-treated with treatment agent 63, was obtained in the same manner as in Example 1, except that quantum dot EX1 obtained in Synthesis Example 1 was replaced with quantum dot EX2 obtained in Synthesis Example 2, and treatment agent 1 was replaced with treatment agent 63 in Table 10.

[0080] [Example 142] An ink composition 142 was obtained in the same manner as in Example 1, except that the quantum dot EX1 obtained in Synthesis Example 1 was replaced with the quantum dot EX2 obtained in Synthesis Example 2, and the treatment agent 1 was replaced with the treatment agent 110 in Table 16. The quantum dots contained in the core-shell type semiconductor particles, in which the core is ZnTeSe and the shell is a two-layer ZnSe / ZnS, were surface-treated with the treatment agent 110.

[0081] [Example 143] An ink composition 143 was obtained in the same manner as in Example 1, except that the quantum dot EX1 obtained in Synthesis Example 1 was replaced with the quantum dot EX2 obtained in Synthesis Example 2, and the treatment agent 1 was replaced with the treatment agent 132 in Table 19, and the procedure was the same as in Example 1, in which core-shell type semiconductor particles, in which the core is ZnTeSe and the shell is a two-layer ZnSe / ZnS, were surface-treated with the treatment agent 132.

[0082] [Example 144] An ink composition 144 was obtained in the same manner as in Example 1, except that the quantum dot EX1 obtained in Synthesis Example 1 was replaced with the quantum dot EX3 obtained in Synthesis Example 3, and treatment agent 1 was replaced with treatment agent 7 in Table 2, thereby surface-treated quantum dots containing core-shell type semiconductor particles, in which the core is AgInS2 and the shell is ZnS, with treatment agent 7.

[0083] [Example 145] An ink composition 145 was obtained in the same manner as in Example 1, except that the quantum dot EX1 obtained in Synthesis Example 1 was replaced with the quantum dot EX3 obtained in Synthesis Example 3, and the treatment agent 1 was replaced with the treatment agent 66 in Table 10, thereby surface-treated quantum dots containing core-shell type semiconductor particles, in which the core is AgInS2 and the shell is ZnS, with the treatment agent 66.

[0084] [Example 146] An ink composition 146 was obtained in the same manner as in Example 1, except that the quantum dot EX1 obtained in Synthesis Example 1 was replaced with the quantum dot EX3 obtained in Synthesis Example 3, and the treatment agent 1 was replaced with the treatment agent 84 in Table 13, thereby obtaining an ink composition 146 containing quantum dots in which core-shell type semiconductor particles, having an AgInS2 core and a ZnS shell, were surface-treated with the treatment agent 84.

[0085] [Example 147] An ink composition 147 was obtained in the same manner as in Example 1, except that the quantum dot EX1 obtained in Synthesis Example 1 was replaced with the quantum dot EX3 obtained in Synthesis Example 3, and the treatment agent 1 was replaced with the treatment agent 90 in Table 13, thereby obtaining an ink composition 147 containing quantum dots in which core-shell type semiconductor particles, having an AgInS2 core and a ZnS shell, were surface-treated with the treatment agent 90.

[0086] [Table 1]

[0087] [Table 2]

[0088] [Table 3]

[0089] [Table 4]

[0090] [Table 5]

[0091] [Table 6]

[0092] [Table 7]

[0093] [Table 8]

[0094] Table 9

[0095] Table 10

[0096] Table 11

[0097] Table 12

[0098] Table 13

[0099] Table 14

[0100] Table 15

[0101] Table 16

[0102] Table 17

[0103] Table 18

[0104] Table 19

[0105] [Table 20]

[0106] [Table 21]

[0107] (Ink stability evaluation) The time-dependent stability of the fluorescence quantum yield was evaluated for ink compositions 1-147 and R1-R3 obtained in the examples and comparative examples. A quantum efficiency measurement system QE-2000 manufactured by Otsuka Electronics Co., Ltd. was used to measure the fluorescence quantum yield. The ratio of the fluorescence quantum yield after 100 hours of storage in a sealed container in air to the fluorescence quantum yield after synthesis (set to 1) was used as an indicator of ink stability. The results are shown in Tables 22-25. The criteria are as follows: A+: 1.0 or less, 0.80 or more A: Less than 0.80, 0.75 or higher B+: Less than 0.75, 0.70 or higher B: Less than 0.70, 0.65 or higher C+: Less than 0.65, 0.60 or higher C: Less than 0.60, 0.55 or higher D+: Less than 0.55, 0.50 or higher D: Less than 0.50

[0108] (Evaluation of ink film-forming properties) The film-forming properties of ink compositions 1-147 and R1-R3 obtained in the examples and comparative examples were evaluated. After cleaning with an electronics industry detergent and solvent, the ink compositions were applied to glass substrates that had been further treated with UV ozone by spin coating and subsequent heat treatment with a hot plate at 80°C to form films. The arithmetic mean roughness (Ra) (nm) of the formed films was determined according to the method specified in Japanese Industrial Standard (JIS) R1683:2014 and evaluated according to the following criteria. The results are shown in Tables 22-25. The criteria are as follows. A: 0 or more, 3.0 or less B: More than 3.0, less than 5.0 C: over 5.0, under 10.0 D: Exceeding 10.0

[0109] (Evaluation of electric field-emitting elements) The electroluminescent element performance was evaluated for ink compositions 1 to 147 and R1 to R3 obtained in the examples and comparative examples. Vacuum deposition was performed in 10 -6 The experiment was conducted in a Torr vacuum without temperature control, such as heating or cooling of the substrate. The light emission characteristics of the element were measured using an electroluminescent element with a light-emitting element area of ​​2 mm × 2 mm.

[0110] A hole-injection layer with a thickness of 20 nm was obtained by spin coating a molybdenum oxide nanoparticle dispersion (concentration 2.3-2.7% by mass) purchased from Sigma-Aldrich onto a cleaned glass plate with an ITO electrode. The plate was dried at 150°C for 20 minutes. Next, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] was dissolved in monochlorobenzene at a concentration of 1.2% by mass, coated by spin coating, and dried at 110°C for 20 minutes to form a hole-transport layer with a thickness of 40 nm. On top of this, the ink composition of the present invention obtained in the examples and comparative examples was diluted 20-fold with mesitylene, coated by spin coating, and dried under a nitrogen atmosphere at 25°C for 5 minutes to form a 25 nm light-emitting layer. On top of that, Avantama's zinc oxide nanoparticle isopropanol dispersion N-10 was coated by spin coating, and then heated and dried on an 80°C hot plate for 20 minutes to form an 80 nm electron transport layer. Finally, 200 nm of aluminum (Al) was deposited to form electrodes and obtain an electroluminescent element. The obtained element had a current density of 10 mA / cm². 2 The luminous efficiency (cd / A) when driven at 6V, and the relative brightness (=(brightness after 100 hours) / (initial brightness)) after 100 hours of continuous operation were measured. The results are shown in Tables 22-25. When using the ink composition of Example 1, the external quantum efficiency was 4.5% and the luminous brightness was 20,000 (cd / m²) at 6V. 2It exhibited red emission, with a peak wavelength of 628 nm in its emission spectrum and a full width at half maximum of 28 nm. The evaluation criteria for luminous efficiency (cd / A) and relative brightness after 100 hours of continuous operation are as follows.

[0111] • Luminous efficiency (cd / A) A+: 5.5 or higher A: Less than 5.5, 5.0 or higher B+: Below 5.0, 4.5 or higher B: Less than 4.5, 4.0 or higher C+: Less than 4.0, 3.5 or higher C: Less than 3.5, 3.0 or higher D+: Less than 3.0, 2.0 or higher D: Less than 2.0

[0112] Relative luminance A+: 1.0 or less, 0.60 or more A: Less than 0.60, 0.65 or higher B+: Less than 0.65, 0.60 or higher B: Less than 0.60, 0.55 or higher C+: Less than 0.55, 0.50 or higher C: Less than 0.50, 0.45 or higher D+: Less than 0.45, 0.30 or higher D: Less than 0.30

[0113] [Table 22]

[0114] [Table 23]

[0115] [Table 24]

[0116] [Table 25]

Claims

1. A quantum dot containing semiconductor particles surface-treated with a surface treatment agent, wherein the surface treatment agent is represented by any of the following general formulas (1) to (4). 【Chemistry 1】 [In general formula (1), X １ is O, S, or NL １ And, L １ This is a hydrogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, or a substituted or unsubstituted monovalent aromatic heterocyclic group. Z １ is either O or S, R １ ~R ６ is, A １ A ２ And, A １ is a direct bond, -CO-, -COO-, or -SO ２ -. A ２ These are a hydrogen atom, a halogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic heterocyclic group, a cyano group, a nitro group, an amino group, a sulfanyl group, or a carboxyl group. However, A ２ When is a hydrogen atom, halogen atom, cyano group, nitro group, amino group, sulfanyl group, or carboxyl group, A １ This is a direct bond. R １ ~R ６ At least one of them has an amino group, a sulfanyl group, or a carboxyl group. 【Chemistry 2】 [In general formula (2), X ２ is O, S, or NL １ And, L １ This is a hydrogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, or a substituted or unsubstituted monovalent aromatic heterocyclic group. Z ２ is either O or S, R ７ ~R １２ is, A １ A ２ And, A １ These are direct bonds, -CO-, -COO-, or -SO ２ - and A ２ These are a hydrogen atom, a halogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic heterocyclic group, a cyano group, a nitro group, an amino group, a sulfanyl group, or a carboxyl group. However, A ２ When is a hydrogen atom, halogen atom, cyano group, nitro group, amino group, sulfanyl group, or carboxyl group, A １ This is a direct bond. R ７ ~R １２ At least one of them has an amino group, a sulfanyl group, or a carboxyl group. However, general formula (2) is excluded from the case where it is expressed by general formula (1). 【Transformation 3】 [In general formula (3), X ３ is O, S, or NL １ And, L １ This is a hydrogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, or a substituted or unsubstituted monovalent aromatic heterocyclic group. Z ３ is either O or S, R １３ ~R １６ is, A １ A ２ And, A １ These are direct bonds, -CO-, -COO-, or -SO ２ - and A ２ These are a hydrogen atom, a halogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic heterocyclic group, a cyano group, a nitro group, an amino group, a sulfanyl group, or a carboxyl group. However, A ２ When is a hydrogen atom, halogen atom, cyano group, nitro group, amino group, sulfanyl group, or carboxyl group, A １ This is a direct bond. R １３ ~R １６ At least one of them has an amino group, a sulfanyl group, or a carboxyl group. However, general formula (3) is excluded from cases where it is expressed by general formula (1) or (2). 【Chemistry 4】 [In general formula (4), X ４ is O, S, or NL １ And, L １ This is a hydrogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, or a substituted or unsubstituted monovalent aromatic heterocyclic group. Z ４ is either O or S, R １７ ~R ２０ is, A １ A ２ And, A １ These are direct bonds, -CO-, -COO-, or -SO ２ - and A ２ These are a hydrogen atom, a halogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic heterocyclic group, a cyano group, a nitro group, an amino group, a sulfanyl group, or a carboxyl group. However, A ２ When is a hydrogen atom, halogen atom, cyano group, nitro group, amino group, sulfanyl group, or carboxyl group, A １ This is a direct bond. R １７ ~R ２０ At least one of them has an amino group, a sulfanyl group, or a carboxyl group. However, this excludes the case where general formula (4) is expressed by any of general formulas (1) to (3).

2. An ink composition comprising the quantum dots and dispersion medium described in claim 1.

3. An electroluminescent element having an anode, a light-emitting layer, and a cathode on a substrate, wherein the light-emitting layer includes the quantum dot described in claim 1.

Images