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JP-2026074501-A - Quantum dots, electroluminescent elements, and ink compositions

JP2026074501AJP 2026074501 AJP2026074501 AJP 2026074501AJP-2026074501-A

Abstract

【assignment】 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). [Selection Diagram] None

Inventors

  • 隅越 俊介
  • 金子 哲也
  • 千阪 二郎

Assignees

  • ａｒｔｉｅｎｃｅ株式会社

Dates

Publication Date
20260507
Application Date
20241021

Claims (3)

  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). [In general formula (1), X1 is O, S, or NL1 , L1 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. Z1 is either O or S, R1 to R6 are A1 A2 , A1 is a direct bond, -CO-, -COO-, or -SO2- , A2 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 carboxyl group. However, when A2 is a hydrogen atom, halogen atom, cyano group, nitro group, amino group, sulfanyl group, or carboxyl group, A1 is a direct bond. At least one of R1 to R6 has an amino group, a sulfanyl group, or a carboxyl group. [In general formula (2), X2 is O, S, or NL1 , L1 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. Z2 is either O or S. R7 to R12 are A1 A2 , A1 is a direct bond, -CO-, -COO-, or -SO2- , A2 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 carboxyl group. However, when A2 is a hydrogen atom, halogen atom, cyano group, nitro group, amino group, sulfanyl group, or carboxyl group, A1 is a direct bond. At least one of R7 to R12 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). [In general formula (3), X 3 is O, S, or NL 1 , L1 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. Z3 is either O or S, R13 to R16 are A1 A2 , A1 is a direct bond, -CO-, -COO-, or -SO2- , A2 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 carboxyl group. However, when A2 is a hydrogen atom, halogen atom, cyano group, nitro group, amino group, sulfanyl group, or carboxyl group, A1 is a direct bond. At least one of R13 to R16 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). [In general formula (4), X 4 is O, S, or NL 1 , L1 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, R17 to R20 are A1 A2 , A1 is a direct bond, -CO-, -COO-, or -SO2- , A2 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 carboxyl group. However, when A2 is a hydrogen atom, halogen atom, cyano group, nitro group, amino group, sulfanyl group, or carboxyl group, A1 is a direct bond. At least one of R17 to R20 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.

Description

This invention relates to quantum dots, electroluminescent devices using the same, and ink compositions. Electroluminescent devices (ELs) are attracting attention as lightweight, thin, low-power, and highly flexible surface-emitting elements. These electroluminescent devices possess many excellent features, including high brightness, fast response, wide viewing angle, thin and lightweight design, and high resolution. Their applications in flat-panel displays and lighting are being explored, and quantum dots are attracting particular attention as a type of electroluminescent device. Quantum dots are tiny, nanoscale semiconductor particles that exhibit behavior intermediate between atomic or molecular behavior and macroscopic solid-state (bulk form) behavior. Nanoscale materials (semiconductor particles) in which charge carriers and excitons are confined in all three dimensions are called quantum dots, and their effective band gap increases as their size decreases. That is, as the size of a quantum dot decreases, its absorption and emission shift to shorter wavelengths, in other words, from the red to the blue direction. Furthermore, by controlling the composition and size of the quantum dots, a wide spectrum from the infrared to the ultraviolet region can be obtained, and by controlling the size distribution, a spectrum 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, using quantum dots made of semiconductor nanocrystals as the light-emitting material. 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, their insulating properties mean they cannot perform adequately in applications such as electroluminescent devices. Therefore, 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 remain insufficient, and there are also challenges with film formation when used in ink compositions. Japanese Patent Publication No. 2004-315661Japanese Patent Publication No. 2008-214363 <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. <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), and tin(IV) oxide. Aluminum sulfide (Al) is a compound of Group III elements and Group V elements of the periodic table, such as aluminum sulfide (AlP), aluminum arsenide (AlAs), aluminum antimonide (AlSb), 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). 2S3 ) , aluminum selenide ( Al2Se3 ), gallium sulfide ( Ga2S3 ), gallium selenide (GaSe, Ga2Se3 ) , gallium telluride (GaTe, Ga2Te3 ) , indium oxide (In2O3 ) , indium sulfide ( In2S3 , InS ), indium selenide ( In2Se3 ), indium telluride ( In2Te3 ) Compounds of Group III and Group VI elements of the periodic table, such as 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), etc., and copper(I) oxide ( Cu2 Examples include compounds of Group I and Group VI elements of the periodic table, such as O), 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), and silver bromide (AgBr), and Group I-III- VI2 chalcopylite type 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