Light-emitting element

Abstract

To provide a light-emitting element with excellent luminous efficiency. [Solution] A light-emitting element having an anode, a cathode, and a first layer and a second layer provided between the anode and the cathode, wherein the first layer is a layer containing a fluorescent compound whose absolute difference between the energy level of the lowest triplet excited state and the energy level of the lowest singlet excited state is greater than 0.50 eV, and two or more types of compound T, and the second layer is a layer containing a crosslinked compound having a crosslinking group, wherein compound T is (i) a compound whose absolute difference between the energy level of the lowest triplet excited state and the energy level of the lowest singlet excited state is 0.25 eV or less, and / or (ii) a compound represented by formula (T-1), TIFF2026053955000081.tif20170

Description

[Technical Field]

[0001] This invention relates to a light-emitting element. [Background technology]

[0002] Organic electroluminescent elements (hereinafter also referred to as "light-emitting elements") can be suitably used in display and lighting applications, and research and development are underway. For example, Patent Document 1 describes an organic light-emitting device having an organic layer containing a crosslinked body of a crosslinking material and an organic layer containing a compound represented by a specific formula and a fluorescent compound represented by a specific formula. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2018 / 062277 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, the light-emitting elements described above did not always have sufficient luminous efficiency. Therefore, the present invention aims to provide a light-emitting element with excellent luminescence efficiency. [Means for solving the problem]

[0005] The present invention provides the following [1] to

[13] . [1] A light-emitting element having an anode, a cathode, and a first layer and a second layer provided between the anode and the cathode, The first layer is a layer containing a fluorescent compound in which the absolute value of the difference between the energy level of the lowest triplet excited state and the energy level of the lowest singlet excited state is greater than 0.50 eV, and two or more compounds T that satisfy at least one of requirements (i) and (ii). A light-emitting element, wherein the second layer is a layer containing a crosslinked compound having a crosslinking group. (i) The absolute value of the difference between the energy level of the lowest triplet excited state and the energy level of the lowest singlet excited state is 0.25 eV or less. (ii) It is a compound represented by formula (T-1). [ka] [In the formula, n T1 n represents a non-negative integer. T1 If multiple instances exist, they may be identical or different. Ar T1 represents a substituted amino group or a monovalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other, forming a ring with the atom to which each substituent is bonded. T1 If multiple elements exist, they may be identical or different, and they may be directly bonded to each other or bonded via divalent groups to form a ring. However, Ar T1 In this case, the monovalent heterocyclic group is the nitrogen atom that does not form a double bond within the ring. It is a monovalent heterocyclic group that contains and does not contain a group represented by =N-, a group represented by -C(=O)-, a group represented by -S(=O)-, or a group represented by -S(=O)2- within the ring. L T1 represents a divalent group, which may have substituents. If there are multiple substituents, they may be the same or different, and they may bond to each other to form a ring with the atom to which each substituent is bonded. T1 If multiple elements exist, they may be identical or different, and they may be directly bonded to each other or bonded via divalent groups to form a ring. Ar T2is a group represented by -C(=O)-, a group represented by -S(=O)-, a group represented by -S(=O)2-, an aromatic hydrocarbon group having an electron-withdrawing group, an aromatic hydrocarbon group containing a group represented by -C(=O)- in the ring, or a heterocyclic group containing at least one group selected from the group consisting of a group represented by =N-, a group represented by -C(=O)-, a group represented by -S(=O)-, and a group represented by -S(=O)2- in the ring, and these groups may have substituents. When there are a plurality of these substituents, they may be the same or different, and may be bonded to each other to form a ring together with the atoms to which they are respectively bonded. n T2 represents an integer of 1 or more. However, Ar T2 is a group represented by -C(=O)-, a group represented by -S(=O)-, or a group represented by -S(=O)2-, n T2 is 2. Ar T1 and L T1 may be directly bonded or bonded via a divalent group to form a ring. Ar T2 and L T1 may be directly bonded or bonded via a divalent group to form a ring. Ar T1 and Ar T2 may be directly bonded or bonded via a divalent group to form a ring.] [2] At least one of the above-mentioned Ar T1 contains a nitrogen atom that does not form a double bond in the ring, and in the ring, a group represented by =N-, a group represented by -C(=O)-, a group represented by -S(=O)-, and a group represented by -S(=O)2- are not included. It is a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from a polycyclic heterocyclic compound, and the group may have a substituent. The light-emitting device according to [1]. [3] The light-emitting device according to [2], wherein the polycyclic heterocyclic compound is a tricyclic, tetracyclic, pentacyclic or hexacyclic heterocyclic compound. [4] The above-mentioned Ar T2The light-emitting element is a group represented by -C(=O)-, a group represented by -S(=O)2-, an aromatic hydrocarbon group having an electron-withdrawing group, or a heterocyclic group containing in the ring at least one group selected from the group consisting of a group represented by =N-, a group represented by -C(=O)-, and a group represented by -S(=O)2-, and these groups may have substituents, as described in any of [1] to [3]. [5] A light-emitting element according to any one of [1] to [4], wherein at least one of the compounds T satisfies requirement (ii). [6] The light-emitting element according to any one of [1] to [5], wherein the first layer contains two or more compounds T that satisfy requirement (ii). [7] The light-emitting element according to any one of [1] to [6], wherein the fluorescent compound is a fluorescent compound represented by formula (B). [ka] [In the formula, n 1B This represents an integer between 0 and 15 (inclusive). Ar 1B represents an aromatic hydrocarbon group of a fused ring, and these groups may have substituents. If there are multiple substituents, they may be bonded to each other, forming a ring with the atom to which each substituent is bonded. R 1B R represents an alkyl group, cycloalkyl group, alkoxy group, cycloalkoxy group, aryl group, monovalent heterocyclic group, substituted amino group, alkenyl group, cycloalkenyl group, alkynyl group, or cycloalkynyl group, and these groups may have substituents. 1B If multiple atoms exist, they may be identical or different, and they may bond to each other, forming a ring with the carbon atoms to which they are bonded. [8] The aforementioned Ar 1BThe light-emitting element according to [7], wherein the group is obtained by removing one or more hydrogen atoms directly bonded to carbon atoms constituting the ring from a naphthalene ring, anthracene ring, phenanthrene ring, dihydrophenanthrene ring, triphenylene ring, naphthalene ring, fluorene ring, spirobifluorene ring, pyrene ring, perylene ring, chrysene ring, indene ring, fluorantene ring, benzofluorantene ring, or acenaphthofluorantene ring, and these groups may have substituents. [9] The aforementioned R 1B The light-emitting element according to [7] or [8], wherein the group is an alkyl group, an aryl group, or a substituted amino group, and these groups may have substituents.

[10] The light-emitting element according to any one of [1] to [9], wherein the compound having the crosslinking group is a polymer compound containing a structural unit represented by formula (Z) and / or a structural unit represented by formula (Z'), or a compound represented by formula (Z''). [ka] [In the formula, n represents an integer greater than or equal to 1. nA represents a non-negative integer. If there are multiple nA values, they may be the same or different. Ar 3 represents a hydrocarbon group, a heterocyclic group, or a group in which at least one hydrocarbon group and at least one heterocyclic group are directly bonded, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which each substituent is bonded. L AR' represents an alkylene group, a cycloalkylene group, an arylene group, a divalent heterocyclic group, a group represented by -N(R')-, an oxygen atom, or a sulfur atom, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which they are bonded. R' represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which they are bonded. A If multiple instances exist, they may be identical or different. X represents a crosslinking group. If there are multiple X's, they may be the same or different. [ka] [In the formula, mA, m, and c each independently represent a non-negative integer. If there are multiple mA values, they may be the same or different. If there are multiple m values, they may be the same or different. Ar 5 represents a hydrocarbon group, a heterocyclic group, or a group in which at least one hydrocarbon group and at least one heterocyclic group are directly bonded, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which each is bonded. 5 If multiple instances exist, they may be identical or different. Ar 4 and Ar 6 Each of these independently represents an arylene group or a divalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which they are bonded. K AR'' represents an alkylene group, a cycloalkylene group, an arylene group, a divalent heterocyclic group, a group represented by -N(R'')-, an oxygen atom, or a sulfur atom, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which they are bonded. R'' represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which they are bonded. K A If multiple instances exist, they may be identical or different. X' represents a hydrogen atom, a bridging group, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which each substituent is bonded. If there are multiple X's, they may be the same or different, provided that at least one X' is a bridging group. [ka] [In the formula, m B1 , m B2 and m B3 Each of these independently represents a non-negative integer. There are multiple m B1 They may be the same or different. B3 If multiple instances exist, they may be identical or different. Ar 7 represents a hydrocarbon group, a heterocyclic group, or a group in which at least one hydrocarbon group and at least one heterocyclic group are directly bonded, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which each is bonded. 7 If multiple instances exist, they may be identical or different. L B1R''' represents an alkylene group, a cycloalkylene group, an arylene group, a divalent heterocyclic group, a group represented by -N(R''')-, an oxygen atom, or a sulfur atom, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which they are bonded. R''' represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which they are bonded. B1 If multiple X''s exist, they may be identical or different. X'' represents a bridging group, a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may have substituents. If multiple substituents exist, they may be identical or different, and they may be bonded to each other, forming a ring with the atom to which each substituent is bonded. Multiple X''s may be identical or different. However, at least one of the multiple X''s is a bridging group.

[11] The light-emitting element according to any one of [1] to

[10] , wherein the first layer further contains at least one selected from the group consisting of hole transport material, hole injection material, electron transport material, electron injection material, light-emitting material, and antioxidant.

[12] A light-emitting element according to any one of [1] to

[11] , wherein the first layer and the second layer are adjacent to each other.

[13] The light-emitting element according to any one of [1] to

[12] , wherein the second layer is a layer provided between the anode and the first layer. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a light-emitting element with excellent luminescence efficiency. [Modes for carrying out the invention]

[0007] Preferred embodiments of the present invention will be described in detail below.

[0008] <Explanation of common terms> Terms used in this specification, unless otherwise specified, have the following meanings:

[0009] Me represents a methyl group, Et represents an ethyl group, Bu represents a butyl group, i-Pr represents an isopropyl group, and t-Bu represents a tert-butyl group.

[0010] "Room temperature" means 25°C. The hydrogen atom may be a deuterium atom or a light hydrogen atom. In formulas representing metal complexes, solid lines indicating bonds with the central metal represent ionic bonds, covalent bonds, or coordinate bonds.

[0011] "Low molecular weight compounds" are those that do not have a molecular weight distribution and have a molecular weight of 1 × 10⁻⁶. 4 This refers to the following compounds.

[0012] A "polymer compound" is defined as a compound that has a molecular weight distribution and whose number-average molecular weight in terms of polystyrene is 1 × 10⁻⁶. 3 (For example, 1 x 10) 3 ~1 × 10 8 It refers to a polymer that is ). A "constituent unit" refers to one or more units present in a polymer compound. Constituent units present in two or more units in a polymer compound are generally also called "repeating units." The polymer compound may be a block copolymer, a random copolymer, an alternating copolymer, a graft copolymer, or any other form. The terminal groups of a polymer compound are preferably stable groups, because if polymerization-active groups remain intact, the luminescence properties may deteriorate when the polymer compound is used to fabricate a light-emitting device. Preferably, the terminal groups of a polymer compound are groups that are conjugately bonded to the main chain of the polymer compound, such as aryl groups or monovalent heterocyclic groups that are bonded to the main chain of the polymer compound via carbon-carbon bonds.

[0013] The alkyl group may be either linear or branched. The number of carbon atoms in a linear alkyl group is usually 1 to 50, preferably 1 to 20, and more preferably 1 to 10, not including the number of carbon atoms in the substituents. The number of carbon atoms in a branched alkyl group is usually 3 to 50, preferably 3 to 20, and more preferably 4 to 10, not including the number of carbon atoms in the substituents.

[0014] Alkyl groups may have substituents. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, 2-butyl, isobutyl, tert-butyl, pentyl, isoamyl, 2-ethylbutyl, hexyl, heptyl, octyl, 2-ethylhexyl, 3-propylheptyl, decyl, 3,7-dimethyloctyl, 2-ethyloctyl, 2-hexyldecyl, and dodecyl groups. In addition, alkyl groups may be groups in which some or all of the hydrogen atoms in these groups are substituted with substituents (for example, trifluoromethyl, pentafluoroethyl, perfluorobutyl, perfluorohexyl, perfluorooctyl, 3-phenylpropyl, 3-(4-methylphenyl)propyl, 3-(3,5-di-hexylphenyl)propyl, and 6-ethyloxyhexyl groups).

[0015] The number of carbon atoms in a "cycloalkyl group," excluding the number of carbon atoms of substituents, is typically 3 to 50, preferably 3 to 20, and more preferably 4 to 10. Cycloalkyl groups may have substituents. Examples of cycloalkyl groups include cyclohexyl groups and groups in which some or all of the hydrogen atoms in the group are substituted with substituents.

[0016] The number of carbon atoms in the alkylene group, excluding the number of carbon atoms in substituents, is usually 1 to 50, preferably 1 to 20, and more preferably 1 to 10. The alkylene group may have substituents. Examples of alkylene groups include the methylene group, ethylene group, propylene group, butylene group, hexylene group, octylene group, and groups in which some or all of the hydrogen atoms in these groups are substituted with substituents.

[0017] The number of carbon atoms in the "cycloalkylene group," excluding the number of carbon atoms of substituents, is usually 3 to 50, preferably 4 to 20, and more preferably 5 to 10. The cycloalkylene group may have substituents. Examples of cycloalkylene groups include the cyclohexylene group and groups in which some or all of the hydrogen atoms in the cycloalkylene group are substituted with substituents.

[0018] An "aromatic hydrocarbon group" refers to a group obtained by removing one or more hydrogen atoms directly bonded to the carbon atoms that make up the ring from an aromatic hydrocarbon. A group obtained by removing one hydrogen atom directly bonded to the carbon atoms that make up the ring from an aromatic hydrocarbon is also called an "aryl group." A group obtained by removing two hydrogen atoms directly bonded to the carbon atoms that make up the ring from an aromatic hydrocarbon is also called an "arylene group." The number of carbon atoms in an aromatic hydrocarbon group, excluding the number of carbon atoms in substituents, is typically 6 to 60, preferably 6 to 40, and more preferably 6 to 20.

[0019] Examples of "aromatic hydrocarbon groups" include monocyclic aromatic hydrocarbons (for example, benzene) or polycyclic aromatic hydrocarbons (for example, bicyclic aromatic hydrocarbons such as naphthalene, indene, naphthoquinone, indenone, and tetralone; tricyclic aromatic hydrocarbons such as anthracene, phenanthrene, dihydrophenanthrene, fluorene, anthraquinone, phenanthoquinone, and fluorenone; tetracyclic aromatic hydrocarbons such as benzoanthracene, benzophenanthrene, and benzofluorene; pentacyclic aromatic hydrocarbons such as dibenzoanthracene, dibenzophenanthrene, dibenzofluorene, indenofluorene, and benzofluorantene; hexacyclic aromatic hydrocarbons such as spirobifluorene; and heptacyclic aromatic hydrocarbons such as benzospirobifluorene and acenaphthofluorantene), from which one or more hydrogen atoms directly bonded to the carbon atoms constituting the ring have been removed, and groups in which some or all of the hydrogen atoms in the group have been substituted with substituents. Aromatic hydrocarbon groups include groups formed by the bonding of multiple such groups. Aromatic hydrocarbon groups may have substituents.

[0020] The aryl group may have substituents. Examples of aryl groups include the phenyl group, naphthyl group, anthracenyl group, pyrenyl group, fluorenyl group, biphenyl group, and groups in which some or all of the hydrogen atoms in these groups are substituted with substituents. The aryl group includes groups formed by the bonding of multiple such groups.

[0021] Arylene groups may have substituents. Examples of arylene groups include phenylene groups, naphthalenediyl groups, anthracenediyl groups, phenanthrenediyl groups, dihydrophenanthrenediyl groups, naphthalenediyl groups, fluororangeyl groups, pyrenediyl groups, perylenediyl groups, chrysendiyl groups, and groups in which some or all of the hydrogen atoms in these groups are substituted with substituents. Arylene groups include groups formed by the bonding of multiple such groups.

[0022] The "alkoxy group" may be either linear or branched. The number of carbon atoms in a linear alkoxy group, excluding the number of carbon atoms of substituents, is usually 1 to 50, preferably 1 to 20, and more preferably 1 to 10. The number of carbon atoms in a branched alkoxy group, excluding the number of carbon atoms of substituents, is usually 3 to 50, preferably 3 to 20, and more preferably 4 to 10. The alkoxy group may have substituents. Examples of alkoxy groups include methoxy, ethoxy, isopropyl, butyl, hexyl, 2-ethylhexyl, 3,7-dimethyloctyl, lauryl, and groups in which some or all of the hydrogen atoms in these groups are substituted with substituents.

[0023] The number of carbon atoms in the "cycloalkoxy group," excluding the number of carbon atoms of substituents, is usually 3 to 50, preferably 3 to 20, and more preferably 4 to 10. The cycloalkoxy group may have substituents. Examples of cycloalkoxy groups include the cyclohexyloxy group and groups in which some or all of the hydrogen atoms in the group are substituted with substituents.

[0024] The number of carbon atoms in an "aryloxy group" is usually 6-6, not including the number of carbon atoms in the substituents. It is 0, preferably 6 to 40, and more preferably 6 to 20. The aryloxy group may have substituents. Examples of aryloxy groups include the phenoxy group, naphthyloxy group, anthracenyloxy group, pyrenyloxy group, and groups in which some or all of the hydrogen atoms in these groups are substituted with substituents.

[0025] A "heterocyclic group" refers to a group obtained by removing one or more hydrogen atoms directly bonded to the atoms (carbon atoms or heteroatoms) that make up the ring from a heterocyclic compound. Among heterocyclic groups, "aromatic heterocyclic groups," which are groups obtained by removing one or more hydrogen atoms directly bonded to the atoms that make up the ring from an aromatic heterocyclic compound, are preferred. A group obtained by removing p hydrogen atoms (where p is an integer of 1 or more) directly bonded to the atoms that make up the ring from a heterocyclic compound is also called a "p-valent aromatic heterocyclic group."

[0026] Examples of "aromatic heterocyclic compounds" include compounds in which the heterocycle itself exhibits aromaticity, such as azoles, thiophenes, furans, pyridines, diazabenzenes, triazines, azanaphthalenes, diazanaphthalenes, and carbazoles, as well as compounds in which an aromatic ring is fused to the heterocycle, even if the heterocycle itself does not exhibit aromaticity, such as phenoxazines, phenothiazines, and benzopyrans.

[0027] The number of carbon atoms in the heterocyclic group, excluding the number of carbon atoms in the substituents, is typically 1 to 60, preferably 2 to 40, and more preferably 3 to 20. The number of heteroatoms in the heterocyclic group, excluding the number of heteroatoms in the substituents, is typically 1 to 30, preferably 1 to 10, more preferably 1 to 5, and even more preferably 1 to 3.

[0028] Examples of heterocyclic groups include monocyclic heterocyclic compounds (e.g., furan, thiophene, oxadiazole, thiadiazole, pyrrole, diazole, triazole, tetrazole, pyridine, diazabenzene, and triazine) or polycyclic heterocyclic compounds (e.g., azanaphthalene, diazanaphthalene, benzofuran, benzothiophene, indole, azaindole, diazindole, benzodiazole, benzothiadiazole, benzotriazole, benzothiophene) Bicyclic heterocyclic compounds such as dioxides, benzothiophene oxide, and benzopyranone; dibenzofuran, dibenzothiophene, dibenzothiophene dioxide, dibenzothiophene oxide, dibenzopyranone, dibenzobolol, dibenzosilol, dibenzophosphole, dibenzoselenophene, carbazole, azacarbazole, diazacarbazole, phenoxazine, phenothiazine, 9,10-dihydroacridine, 5,10-dihydrophenazine, acridone, phenazavolin, Tricyclic heterocyclic compounds such as phenophosphatine, phenoselenazine, phenazacillin, azaanthracene, diazaanthracene, azaphenanthrene, and diazaphenanthrene; tetracyclic heterocyclic compounds such as hexazatriphenylene, benzocarbazole, azabenzocarbazole, diazabenzocarbazole, benzonaphthofuran, and benzonaphthothiophene; dibenzocarbazole, indenocarbazole, indenocarbazole, azaindolocarbazole, and diazaindolocarbazole Examples include five-cyclic heterocyclic compounds such as iodine, azaindenocarbazole, and diazaindenocarbazole; six-cyclic heterocyclic compounds such as carbazolocarbazole, benzoindolocarbazole, and benzoindenocarbazole; and seven-cyclic heterocyclic compounds such as dibenzoindolocarbazole and dibenzoindenocarbazole. Examples include groups obtained by removing one or more hydrogen atoms directly bonded to the atoms constituting the ring, and groups in which some or all of the hydrogen atoms in the group are substituted with substituents. Heterocyclic groups include groups in which multiple such groups are bonded. Heterocyclic groups may have substituents.

[0029] A monovalent heterocyclic group may have substituents. Examples of monovalent heterocyclic groups include cyanoacrylate. Examples include enyl groups, pyrrolyl groups, furyl groups, pyridyl groups, piperidinyl groups, quinolinyl groups, isoquinolinyl groups, pyrimidinyl groups, triazinyl groups, and groups in which some or all of the hydrogen atoms in these groups are substituted with substituents. Monovalent heterocyclic groups include groups in which multiple of these groups are bonded together.

[0030] Divalent heterocyclic groups may have substituents. Examples of divalent heterocyclic groups include pyridine, diazabenzene, triazine, azananaphthalene, carbazole, dibenzofuran, dibenzothiophene, dibenzosilol, phenoxazine, phenothiazine, acridine, dihydroacridine, furan, thiophene, azole, diazole, and triazole, specifically those groups obtained by removing two hydrogen atoms directly bonded to the carbon or heteroatom constituting the ring, and groups in which some or all of the hydrogen atoms in the group are substituted with substituents. Divalent heterocyclic groups include groups formed by the bonding of multiple such groups.

[0031] "Halogen atom" refers to a fluorine atom, chlorine atom, bromine atom, or iodine atom.

[0032] The "amino group" may have substituents, and a substituted amino group (i.e., a secondary amino group or a tertiary amino group, more preferably a tertiary amino group) is preferred. Preferred substituents on the amino group are alkyl groups, cycloalkyl groups, aryl groups, or monovalent heterocyclic groups, and these groups may have further substituents. If there are multiple substituents on the amino group, they may be the same or different, and they may be bonded to each other, forming a ring with the nitrogen atom to which each is bonded. The substituted amino group may have further substituents. Examples of substituted amino groups include dialkylamino groups, dicycloalkylamino groups, diarylamino groups, and groups in which some or all of the hydrogen atoms in these groups are substituted with substituents. Examples of substituted amino groups include dimethylamino group, diethylamino group, diphenylamino group, bis(4-methylphenyl)amino group, bis(4-tert-butylphenyl)amino group, bis(3,5-di-tert-butylphenyl)amino group, and groups in which some or all of the hydrogen atoms in these groups are substituted with substituents.

[0033] The "alkenyl group" may be either linear or branched. The number of carbon atoms in a linear alkenyl group, excluding the number of carbon atoms of substituents, is usually 2 to 50, preferably 2 to 20, and more preferably 3 to 10. The number of carbon atoms in a branched alkenyl group, excluding the number of carbon atoms of substituents, is usually 3 to 50, preferably 3 to 20, and more preferably 4 to 10.

[0034] The number of carbon atoms in the "cycloalkenyl group," excluding the number of carbon atoms of substituents, is usually 3 to 50, preferably 4 to 20, and more preferably 5 to 10.

[0035] Alkenyl groups and cycloalkenyl groups may have substituents. Examples of alkenyl groups include vinyl, 1-propenyl, 2-propenyl, 2-butenyl, 3-butenyl, 3-pentenyl, 4-pentenyl, 1-hexenyl, 5-hexenyl, 7-octenyl, and groups in which some or all of the hydrogen atoms in these groups are substituted with substituents. Examples of cycloalkenyl groups include cyclohexenyl, cyclohexadienyl, cyclooctatrienyl, norbornylene, and groups in which some or all of the hydrogen atoms in these groups are substituted with substituents.

[0036] The "alkynyl group" may be either linear or branched. The number of carbon atoms in the alkynyl group, excluding the carbon atoms of substituents, is usually 2 to 50, preferably 2 to 20, and more preferably 3 to 10. The number of carbon atoms in a branched alkynyl group, excluding the carbon atoms of substituents, is... It is not limited to 4-50, preferably 4-20, and more preferably 4-10.

[0037] The number of carbon atoms in the "cycloalkynyl group," excluding the carbon atoms of substituents, is usually 4 to 50, preferably 5 to 20, and more preferably 6 to 10. Alkynyl groups and cycloalkynyl groups may have substituents. Examples of alkynyl groups include ethynyl, 1-propynyl, 2-propynyl, 2-butynyl, 3-butynyl, 3-pentynyl, 4-pentynyl, 1-hexynyl, 5-hexynyl, and groups in which some or all of the hydrogen atoms in these groups are substituted with substituents. Examples of cycloalkynyl groups include cyclooctinyl and groups in which some or all of the hydrogen atoms in this group are substituted with substituents.

[0038] A "crosslinking group" is a group that can generate new bonds by being subjected to heating, ultraviolet irradiation, near-ultraviolet irradiation, visible light irradiation, infrared irradiation, radical reactions, etc. Preferably, the crosslinking group is a crosslinking group selected from group A (i.e., a group represented by any of formulas (XL-1) to (XL-19)). [ka]

[0039] [In the formula, R XL n represents a methylene group, an oxygen atom, or a sulfur atom. XL This represents an integer from 0 to 5. XL If multiple instances exist, they may be identical or different. XL If multiple such groups exist, they may be identical or different. *1 represents the bonding position. These bridging groups may have substituents, and if multiple substituents exist, they may be identical or different, and they may bond to each other, forming a ring with the atom to which each is bonded.

[0040] Examples of "substituents" include halogen atoms, cyano groups, alkyl groups, cycloalkyl groups, aryl groups, monovalent heterocyclic groups, alkoxy groups, cycloalkoxy groups, aryloxy groups, amino groups, substituted amino groups, alkenyl groups, cycloalkenyl groups, alkynyl groups, or cycloalkynyl groups. Substituents may also be bridging groups. If there are multiple substituents, they may be the same or different. Furthermore, if there are multiple substituents, they may bond to each other and form a ring with the atom to which each is bonded, but it is preferable that they do not form a ring.

[0041] Examples of "divalent groups" include alkylene groups, cycloalkylene groups, arylene groups, divalent heterocyclic groups, and -N(R 0 A base represented by )-, -B(R 0 A group represented by -P(R 0 A group represented by -(O=)P(R 0 Examples include groups represented by -, -O-, -S-, -Se-, -S(=O)-, -S(=O)2-, and -C(=O)-. Divalent groups include groups formed by the bonding of multiple of these groups. Divalent groups may have substituents. If there are multiple substituents, they may be the same or different, and they may bond to each other to form a ring with the atom to which each substituent is bonded. 0 represents a hydrogen atom or substituent. R 0 Examples of substituents include hydrogen atoms, alkyl groups, cycloalkyl groups, alkoxy groups, cycloalkoxy groups, aryl groups, aryloxy groups, monovalent heterocyclic groups, substituted amino groups, halogen atoms, and cyano groups. Hydrogen atoms, alkyl groups, cycloalkyl groups, aryl groups, or monovalent heterocyclic groups are preferred, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may bond to each other to form a ring with the atom to which they are bonded.

[0042] In this specification, the values ​​of the energy levels of the lowest singlet excited states (hereinafter also referred to as the "S1 level"), the values ​​of the energy levels of the lowest triplet excited states (hereinafter also referred to as the "T1 level"), and the absolute value of the difference between the S1 level and the T1 level (hereinafter referred to as the "ΔE level") are used. ST Also known as ). The value of ) is obtained by the following method. First, the ground state of the compound is structurally optimized using B3LYP-level density functional theory. In this case, 6-31G* is used as the basis function. Then, using the obtained structurally optimized structure, the values ​​of the S1 level, T1 level, and ΔE of the compound are obtained using B3LYP-level time-dependent density functional theory. ST The value of [the specified value] is calculated. However, if the atom contains an atom for which 6-31G* cannot be used, LANL2DZ is used for that atom. The quantum chemistry calculation program used is Gaussian.

[0043] <First layer> In the light-emitting element of this embodiment, the first layer is a layer containing a fluorescent compound and two or more compounds T that satisfy at least one of requirements (i) and (ii). The first layer may contain one fluorescent compound alone, or two or more. The first layer may contain only two types of compound T, or three or more.

[0044] In the light-emitting element of this embodiment, the number of types of compound T contained in the first layer is usually 2 to 20, preferably 2 to 10, more preferably 2 to 5, even more preferably 2 or 3, and particularly preferably 2, as this facilitates the manufacture of the light-emitting element of this embodiment.

[0045] In the first layer, the total content of the fluorescent compound and all compounds T is limited to a range that allows the first layer to function as such. In the first layer, the total content of the fluorescent compound and all compounds T may be, for example, 1 to 100% by mass on a basis of the total amount of the first layer, and is preferably 10 to 100% by mass, more preferably 30 to 100% by mass, even more preferably 50 to 100% by mass, particularly preferably 70 to 100% by mass, and especially preferably 90 to 100% by mass, as this provides better luminescence efficiency for the light-emitting element of this embodiment.

[0046] In the first layer, the content of the fluorescent compound may be within a range that allows the first layer to function. In the first layer, the content of the fluorescent compound may be, for example, 0.01 to 99 parts by mass, with the total content of the fluorescent compound and all compounds represented by compound T in the first layer being 100 parts by mass. Preferably, it is 0.05 to 90 parts by mass, more preferably 0.1 to 70 parts by mass, even more preferably 0.2 to 50 parts by mass, and particularly preferably 0.5 to 30 parts by mass, as this provides better luminescence efficiency for the light-emitting element of this embodiment. This is in parts, and more preferably 1 to 10 parts by mass.

[0047] In the first layer, the total content of all compounds T is limited to a range that allows the first layer to function as such. In the first layer, the total content of all compounds T may be, for example, 1 to 99.99 parts by mass, with the total content of the fluorescent compound and all compounds T in the first layer being 100 parts by mass. Preferably, it is 10 to 99.95 parts by mass, more preferably 30 to 99.9 parts by mass, even more preferably 50 to 99.8 parts by mass, particularly preferably 70 to 99.5 parts by mass, and especially preferably 90 to 99 parts by mass, as this provides better luminescence efficiency for the light-emitting element of this embodiment.

[0048] In the first layer, the content of each of the two or more compounds T is within a range that allows the first layer to function. In the first layer, the content of each compound T may be 0.1 to 99.9 parts by mass, preferably 1 to 99 parts by mass, more preferably 10 to 90 parts by mass, even more preferably 30 to 70 parts by mass, and particularly preferably 40 to 60 parts by mass, with the total content of all compounds T in the first layer being 100 parts by mass.

[0049] In the first layer, the total content of the two most abundant compounds among two or more compounds T is limited to a range that allows the first layer to function. In the first layer, the total content of the two most abundant compounds among two or more compounds T is, for example, 1 to 100 parts by mass, preferably 10 to 100 parts by mass, more preferably 30 to 100 parts by mass, even more preferably 50 to 100 parts by mass, particularly preferably 70 to 100 parts by mass, and especially preferably 90 to 100 parts by mass, with the total content of all compounds T in the first layer being 100 parts by mass.

[0050] In the first layer, it is preferable that the fluorescent compound interacts with compound T physically, chemically, or electrically. Furthermore, in the first layer, it is preferable that each of the two or more compounds represented by formula (T-1) interacts physically, chemically, or electrically. The above interactions make it possible to improve or adjust, for example, the light emission characteristics, charge transport characteristics, or charge injection characteristics of the light-emitting element of this embodiment. In the light-emitting element of this embodiment, if we explain the light-emitting material as an example, each of the two or more compounds represented by formula (T-1) interacts electrically, and furthermore, the fluorescent compound and compound T interact electrically, and by efficiently transferring electrical energy from compound T to the fluorescent compound, the fluorescent compound can be made to emit light more efficiently, and the light-emitting element of this embodiment has superior luminescence efficiency. From the above viewpoint, in order to obtain better luminescence efficiency of the light-emitting element of this embodiment in the first layer, it is preferable that compound T has at least one function selected from hole injection, hole transport, electron injection, and electron transport. From the above viewpoint, in the first layer, the luminescence efficiency of the light-emitting element of this embodiment is better, so it is preferable that the lowest excited singlet state (S1) of compound T is at a higher energy level than the lowest excited singlet state (S1) of the fluorescent compound. From the above viewpoint, in the first layer, the luminescence efficiency of the light-emitting element of this embodiment is better, so it is preferable that the lowest excited triplet state (T1) of compound T is at a higher energy level than the lowest excited triplet state (T1) of the fluorescent compound.

[0051] As for compound T, it is preferable that it is soluble in solvents capable of dissolving fluorescent compounds, since the light-emitting element of this embodiment can be fabricated by a wet process.

[0052] Since the luminescent efficiency of the light-emitting element of this embodiment is superior, the first layer is preferably a layer containing a host material and a guest material. If the first layer is a layer containing both a host material and a guest material, the first layer may contain either one type of host material or two or more types, but it is preferable that it contains two or more types.

[0053] In the light-emitting element of this embodiment, if the first layer is a layer containing a host material and a guest material, the total content of the host material and guest material in the first layer should be within a range that allows the first layer to function. In the light-emitting element of this embodiment, if the first layer is a layer containing a host material and a guest material, the total content of the host material and guest material in the first layer may be, for example, 1 to 100% by mass based on the total amount of the first layer, but is preferably 10 to 100% by mass, more preferably 30 to 100% by mass, even more preferably 50 to 100% by mass, particularly preferably 70 to 100% by mass, and especially preferably 90 to 100% by mass, as this provides better luminous efficiency for the light-emitting element of this embodiment.

[0054] In the light-emitting element of this embodiment, if the first layer is a layer containing a host material and a guest material, the respective contents of the host material and guest material in the first layer should be within a range that allows the first layer to function. In the light-emitting element of this embodiment, if the first layer is a layer containing a host material and a guest material, the content of the guest material in the first layer may be, for example, 0.01 to 99 parts by mass when the total content of the host material and guest material is 100 parts by mass, and preferably 0.05 to 90 parts by mass, more preferably 0.1 to 70 parts by mass, even more preferably 0.2 to 50 parts by mass, particularly preferably 0.5 to 30 parts by mass, and especially preferably 1 to 10 parts by mass, as this provides better luminous efficiency for the light-emitting element of this embodiment.

[0055] In the light-emitting element of this embodiment, if the first layer is a layer containing a host material and a guest material, it is preferable that the compound T in the first layer is the host material, since the light-emitting element of this embodiment has better luminescence efficiency. In the light-emitting element of this embodiment, if the first layer is a layer containing a host material and a guest material, the fluorescent compound in the first layer is preferably a guest material because it provides better luminescence efficiency to the light-emitting element of this embodiment.

[0056] In the light-emitting element of this embodiment, the host material refers to a material that interacts with the guest material physically, chemically, or electrically. This interaction makes it possible to improve or adjust, for example, the light emission characteristics, charge transport characteristics, or charge injection characteristics of the light-emitting element of this embodiment. In the light-emitting element of this embodiment, if we explain the light-emitting material as an example, the host material and the guest material interact electrically, and by efficiently transferring electrical energy from the host material to the guest material, the guest material can be made to emit light more efficiently, resulting in a higher luminescence efficiency for the light-emitting element of this embodiment. From the above viewpoint, in the light-emitting element of this embodiment, the light-emitting element of this embodiment has superior luminescence efficiency, so it is preferable that the host material has at least one function selected from hole injection, hole transport, electron injection, and electron transport. From the above viewpoint, if we describe the light-emitting element of this embodiment as an example of a light-emitting material, it is preferable that the guest material has light-emitting properties because the light-emitting element of this embodiment has superior light-emitting efficiency. From the above viewpoint, in the light-emitting element of this embodiment, the lowest excited triplet state (T1) of the host material is preferably at a higher energy level than the lowest excited triplet state (T1) of the guest material, since this results in better luminescence efficiency for the light-emitting element of this embodiment. From the above viewpoint, in the light-emitting element of this embodiment, the lowest excited singlet state (S1) of the host material is such that the light-emitting element of this embodiment has better luminescence efficiency, and the guest material has It is preferable that the energy level is higher than the lowest excited singlet state (S1).

[0057] In the light-emitting element of this embodiment, if the first layer is a layer containing a host material and a guest material, the host material is preferably soluble in a solvent capable of dissolving the guest material, since the light-emitting element of this embodiment can be manufactured by a wet process.

[0058] [Compound T] Compound T is preferably a compound with thermally activated delayed fluorescence (TADF) properties (thermally activated delayed fluorescence compound) because it provides superior luminescence efficiency to the light-emitting element of this embodiment. The molecular weight of compound T is preferably 2000 to 10000, more preferably 300 to 3000, even more preferably 350 to 1500, and particularly preferably 400 to 1000. Compound T is preferably a low molecular weight compound. Furthermore, compound T is preferably a compound that does not contain transition metal elements (i.e., a compound composed only of main group elements). Compound T is preferable because it provides better luminescence efficiency to the light-emitting element of this embodiment, thus satisfying requirement (ii).

[0059] Compound T is preferably a different compound from the fluorescent compound described later.

[0060] If compound T satisfies requirement (i), then the ΔE of compound T ST It may be 0.20 eV or less, 0.18 eV or less, 0.16 eV or less, or 0.14 eV or less. Also, if compound T satisfies requirement (i), the ΔE of compound T ST It may be 0.001eV or more, 0.005eV or more, 0.01eV or more, 0.02eV or more, 0.03eV or more, or 0.05eV or more.

[0061] If compound T satisfies requirement (ii), then ΔE of compound T (the compound represented by formula (T-1)) ST It is usually 0.60 eV or less, but may be 0.50 eV or less, 0.45 eV or less, 0.40 eV or less, 0.35 eV or less, 0.30 eV or less, 0.25 eV or less, 0.20 eV or less, 0.15 eV or less, or 0.10 eV or less. Also, if compound T satisfies requirement (ii), the ΔE of compound T (the compound represented by formula (T-1)) STIt may be 0.001eV or more, 0.005eV or more, 0.01eV or more, 0.02eV or more, 0.03eV or more, or 0.05eV or more.

[0062] (The compound represented by formula (T-1)) n T1 This is usually an integer between 0 and 10, and is preferably an integer between 0 and 5, more preferably an integer between 0 and 3, and even more preferably an integer between 0 and 2, as this provides better luminescence efficiency for the light-emitting element of this embodiment. n T2 This is usually an integer between 1 and 15, and is preferably an integer between 1 and 10, more preferably an integer between 1 and 7, even more preferably an integer between 1 and 4, and particularly preferably an integer between 1 and 3, as this provides excellent luminous efficiency for the light-emitting element of this embodiment.

[0063] In this specification, "nitrogen atom that does not form a double bond" means a nitrogen atom that is bonded to the other three atoms by single bonds. "Contains nitrogen atoms that do not form a double bond within the ring" means that the ring contains -N(-R N )-(wherein, R N represents a hydrogen atom or substituent. ) or formula: [ka] This means that it contains the group represented by .

[0064] A "monovalent heterocyclic group (hereinafter also referred to as a "monovalent donor heterocyclic group")" refers to a heterocyclic compound (hereinafter also referred to as a "donor heterocyclic compound") that contains a nitrogen atom that does not form a double bond within the ring and does not contain a group represented by =N-, -C(=O)-, -S(=O)-, or -S(=O)2- within the ring, from which one hydrogen atom directly bonded to an atom constituting the ring has been removed.

[0065] The monovalent donor-type heterocyclic group is preferably a group obtained by removing one hydrogen atom directly bonded to a carbon or nitrogen atom constituting the ring from a donor-type heterocyclic compound, and more preferably a group obtained by removing one hydrogen atom directly bonded to a nitrogen atom constituting the ring from a donor-type heterocyclic compound. These groups may have substituents.

[0066] Examples of donor-type heterocyclic compounds include heterocyclic compounds described in the section on heterocyclic groups above that contain a nitrogen atom that does not form a double bond within the ring, and that do not contain a group represented by =N-, a group represented by -C(=O)-, a group represented by -S(=O)-, or a group represented by -S(=O)2- within the ring.

[0067] In donor-type heterocyclic compounds, the number of nitrogen atoms that do not form a double bond among the atoms constituting the ring is usually 1 to 10, preferably 1 to 5, more preferably 1 to 3, and even more preferably 1 or 2. In donor-type heterocyclic compounds, the number of carbon atoms constituting the ring is usually 1 to 60, preferably 3 to 50, more preferably 5 to 40, even more preferably 7 to 30, and particularly preferably 10 to 25. In donor-type heterocyclic compounds, the number of heteroatoms constituting the ring is usually 1 to 30, preferably 1 to 10, more preferably 1 to 5, even more preferably 1 to 3, and particularly preferably 1 or 2.

[0068] The donor-type heterocyclic compound is preferably an aromatic heterocyclic compound because it provides superior luminescence efficiency to the light-emitting element of this embodiment. The donor-type heterocyclic compound is preferably a polycyclic heterocyclic compound because it provides better luminescence efficiency for the light-emitting element of this embodiment. Specifically, the monovalent donor-type heterocyclic group is preferably a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring (preferably a carbon atom or a nitrogen atom, more preferably a nitrogen atom) from a polycyclic heterocyclic compound that contains a nitrogen atom that does not form a double bond in the ring and does not contain a group represented by =N-, a group represented by -C(=O)-, a group represented by -S(=O)-, and a group represented by -S(=O)2- in the ring, and this group may have substituents. The donor-type heterocyclic compound is preferably a heterocyclic compound containing a 5-membered ring or a 6-membered ring, more preferably a polycyclic heterocyclic compound containing a 5-membered ring or a 6-membered ring, even more preferably a polycyclic heterocyclic compound containing a 6-membered ring, and more preferably a polycyclic heterocyclic compound containing both a 5-membered ring and a 6-membered ring, as this results in superior luminescence efficiency of the light-emitting element in this embodiment. Particularly preferred are the donor-type heterocyclic compounds that include a five-membered ring or a six-membered ring, as exemplified in the section on heterocyclic groups above. When the donor heterocyclic compound is a polycyclic heterocyclic compound, the donor heterocyclic compound is preferably a bicyclic to heptacyclic compound, more preferably a tricyclic to heptacyclic compound, even more preferably carbazole, phenoxazine, phenothiazine, 9,10-dihydroacridine, 5,10-dihydrophenazine, benzocarbazole, dibenzocarbazole, indolocarbazole, or indenocarbazole, particularly preferably carbazole, benzocarbazole, dibenzocarbazole, indolocarbazole, or indenocarbazole, and especially preferably carbazole, indolocarbazole, or indenocarbazole. When the donor heterocyclic compound is a monocyclic heterocyclic compound, an example of the donor heterocyclic compound is pyrrole.

[0069] Ar T1 Examples and preferred ranges of substituted amino groups in Ar are described below. T1 The examples and preferred ranges of substituted amino groups in substituents that may be present are the same as those mentioned above.

[0070] Ar T1 The substituents that may be present are preferably alkyl groups, cycloalkyl groups, alkoxy groups, cycloalkoxy groups, aryl groups, aryloxy groups, monovalent heterocyclic groups, substituted amino groups, halogen atoms, or cyano groups; more preferably alkyl groups, cycloalkyl groups, alkoxy groups, cycloalkoxy groups, aryl groups, monovalent heterocyclic groups, or substituted amino groups; even more preferably alkyl groups, cycloalkyl groups, alkoxy groups, aryl groups, monovalent heterocyclic groups, or substituted amino groups; and particularly preferably alkyl groups, cycloalkyl groups, aryl groups, or substituted amino groups, and these groups may have further substituents.

[0071] Ar T1 The aryl group in the substituent that may be present is preferably a monocyclic or bicyclic to hexacyclic aromatic hydrocarbon from which one hydrogen atom directly bonded to a carbon atom constituting the ring has been removed, since this results in better luminescence efficiency of the light-emitting element of this embodiment. More preferably, it is a monocyclic, bicyclic, or tricyclic aromatic hydrocarbon from which one hydrogen atom directly bonded to a carbon atom constituting the ring has been removed. Even more preferably, it is a group obtained by removing one hydrogen atom directly bonded to a carbon atom constituting the ring from benzene, naphthalene, anthracene, phenanthrene, dihydrophenanthrene, or fluorene. Particularly preferably, it is a group obtained by removing one hydrogen atom directly bonded to a carbon atom constituting the ring from benzene, naphthalene, or fluorene. Particularly preferably, it is a phenyl group, and these groups may have substituents. Ar T1The monovalent heterocyclic group in the substituent that may be present is preferably a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from a monocyclic or bicyclic to hexacyclic heterocyclic compound, as this provides better luminescence efficiency for the light-emitting element of this embodiment. More preferably, it is a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from a monocyclic, bicyclic, or tricyclic heterocyclic compound. Even more preferably, it is furan, thiophene, oxadiazole, thiadiazole, pyrrole, diazole, or tri Azole, pyridine, diazabenzene, triazine, azanafthalene, diazanafthalene, benzofuran, benzothiophene, indole, azaindole, diazaindole, benzodiazole, benzotriazole, dibenzofuran, dibenzothiophene, carbazole, azacarbazole, diazacarbazole, phenoxazine, phenothiazine, 9,10-dihydroacridine, 5,10-dihydrophenazine, acridone, azaanthracene, diazaanthracene, azafe The group is obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from nanthrene or diazaphenanthrene, and is particularly preferably a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from pyridine, diazabenzene, triazine, azanaphthalene, dizanaphthalene, dibenzofuran, dibenzothiophene, carbazole, azacarbazole, diazacarbazole, phenoxazine, phenothiazine, 9,10-dihydroacridine, or 5,10-dihydrophenazine, and is especially preferably a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from pyridine, diazabenzene, triazine, dibenzofuran, dibenzothiophene, carbazole, phenoxazine, phenothiazine, 9,10-dihydroacridine, or 5,10-dihydrophenazine, and is particularly more preferably a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from dibenzofuran, dibenzothiophene, or carbazole, and these groups may have substituents. Ar T1In the substituted amino group in the substituent that may be present, the substituent of the amino group is preferably an aryl group or a monovalent heterocyclic group, more preferably an aryl group, and these groups may have further substituents. Examples and preferred ranges of aryl groups in the substituent of the amino group are: Ar T1 The examples and preferred ranges of aryl groups in substituents that may be present are the same as those for Ar T1 The examples and preferred ranges of monovalent heterocyclic groups in substituents that may be present are the same as those mentioned above.

[0072] Ar T1 The substituents that may be present in the compound are preferably halogen atoms, cyano groups, alkyl groups, cycloalkyl groups, alkoxy groups, cycloalkoxy groups, aryloxy groups, aryl groups, monovalent heterocyclic groups, or substituted amino groups; more preferably alkyl groups, cycloalkyl groups, aryl groups, monovalent heterocyclic groups, or substituted amino groups; even more preferably alkyl groups, cycloalkyl groups, or aryl groups; particularly preferably alkyl groups or cycloalkyl groups, and these groups may have further substituents, but it is preferable that they do not have further substituents. Ar T1 Examples and preferred ranges of aryl groups, monovalent heterocyclic groups, and substituted amino groups in substituents that may or may have are, respectively, Ar T1 The examples and preferred ranges of aryl groups, monovalent heterocyclic groups, and substituted amino groups in the substituents that may be present are the same as those mentioned above.

[0073] Ar T1 At least one of these is preferably a monovalent donor-type heterocyclic group which may have substituents, as this provides better luminescence efficiency for the light-emitting element of this embodiment. Ar T1 This is preferably a monovalent donor-type heterocyclic group, which may have substituents, as it further improves the luminescence efficiency of the light-emitting element of this embodiment.

[0074] ArT1 If multiple groups exist, they may be identical or different, and they may be directly bonded to each other or bonded via divalent groups to form a ring. However, it is preferable that they do not form a ring, as this facilitates the synthesis of the compound represented by formula (T-1). Ar T1 When multiple such groups exist and they bond to each other via a divalent group to form a ring, the divalent group is preferably an alkylene group, a cycloalkylene group, an arylene group, a divalent heterocyclic group, or -N(R T1 A base represented by ')-, -B(R T1 A group represented by ')-, a group represented by -O-, a group represented by -S-, or a group represented by -C(=O)-, more preferably an alkylene group, a cycloalkylene group, or -N(R T1 A base represented by ')-, -B(R T1 The group is represented by ')-, a group represented by -O-, or a group represented by -S-, and more preferably an alkylene group, a group represented by -O-, or a group represented by -S-, and these groups may have substituents.

[0075] In the divalent group, the arylene group is preferably a monocyclic or bicyclic to hexacyclic aromatic hydrocarbon from which two hydrogen atoms directly bonded to the carbon atoms constituting the ring have been removed, more preferably a monocyclic, bicyclic, or tricyclic aromatic hydrocarbon from which two hydrogen atoms directly bonded to the carbon atoms constituting the ring have been removed, and even more preferably benzene, naphthalene, anthracene, phenanthrene, dihydrophenanthrene, or fluorene, which constitute the ring The group is one in which two hydrogen atoms directly bonded to the carbon atoms forming the ring have been removed, and is particularly preferably a group obtained by removing two hydrogen atoms directly bonded to the carbon atoms forming the ring from benzene, naphthalene, or fluorene, and is especially preferably a phenylene group, and these groups may have substituents. In the divalent group, the divalent heterocyclic group is preferably a group obtained by removing two hydrogen atoms directly bonded to the ring-constituting atoms (preferably carbon atoms) from a monocyclic or bicyclic to hexacyclic heterocyclic compound, more preferably a group obtained by removing two hydrogen atoms directly bonded to the ring-constituting atoms (preferably carbon atoms) from a monocyclic, bicyclic, or tricyclic heterocyclic compound, and even more preferably pyridine, diazabenzene, triazine, azananaphthalene, dizananaphthalene, dibenzofuran, dibenzothiophene, carbazole, azacarbazole, diazacarbazole, phenoxazine, phenothiazine, 9,10-dihydroxy The group is obtained by removing two hydrogen atoms directly bonded to the ring-forming atoms (preferably carbon atoms) from droacridine or 5,10-dihydrophenazine, and is particularly preferably a group obtained by removing two hydrogen atoms directly bonded to the ring-forming atoms (preferably carbon atoms) from pyridine, diazabenzene, triazine, carbazole, phenoxazine, phenothiazine, 9,10-dihydroacridine, or 5,10-dihydrophenazine, and is especially preferably a group obtained by removing two hydrogen atoms directly bonded to the ring-forming carbon atoms from pyridine, diazabenzene, or triazine, and these groups may have substituents. Examples and preferred ranges of substituents that the divalent group may have are Ar T1 The examples and preferred ranges of substituents that may be present are the same as those mentioned above.

[0076] R T1 ' represents a hydrogen atom, alkyl group, cycloalkyl group, alkoxy group, cycloalkoxy group, aryl group, aryloxy group, monovalent heterocyclic group, substituted amino group, halogen atom, or cyano group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which each is bonded. R T1' is preferably a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group or a monovalent heterocyclic group, more preferably an alkyl group, a cycloalkyl group, an aryl group or a monovalent heterocyclic group, still more preferably an aryl group or a monovalent heterocyclic group, particularly preferably an aryl group, and these groups may have substituents. R T1 Examples and preferred ranges of the substituents that ' may have are the same as those of the substituents that Ar T1 may have. R T1 Examples and preferred ranges of the aryl group, monovalent heterocyclic group and substituted amino group in ' are the same as those of the aryl group, monovalent heterocyclic group and substituted amino group in the substituents that Ar T1 may have, respectively.

[0077] L T1 In, the divalent group is preferably an alkylene group, a cycloalkylene group, an arylene group, a divalent heterocyclic group, a group represented by -N(R T1 '), a group represented by -B(R T1 '), a group represented by -O-, a group represented by -S-, a group represented by -C(=O)- or a group represented by -S(=O)2- because the light-emitting efficiency of the light-emitting element of this embodiment is more excellent, more preferably an alkylene group, a cycloalkylene group, an arylene group, a divalent heterocyclic group, a group represented by -C(=O)- or a group represented by -S(=O)2-, still more preferably an alkylene group, a cycloalkylene group, an arylene group, a divalent heterocyclic group, particularly preferably an arylene group or a divalent heterocyclic group, and especially preferably an arylene group, and these groups may have substituents. L T1 Examples and preferred ranges of the substituents that may have are the same as those of the substituents that Ar T1 may have. L T1If multiple groups exist, they may be identical or different, and they may be directly bonded to each other or bonded via divalent groups to form a ring. However, it is preferable that they do not form a ring, as this facilitates the synthesis of the compound represented by formula (T-1). L T1 Examples and preferred ranges of divalent groups in cases where multiple divalent groups exist and are bonded to each other via divalent groups to form a ring are Ar T1 The examples and preferred ranges of divalent groups are the same as those in the case where multiple divalent groups exist and are bonded to each other via divalent groups to form a ring.

[0078] Ar T2 In this context, the aromatic hydrocarbon group having an electron-withdrawing group is preferably an aromatic hydrocarbon group having an electron-withdrawing group as a substituent, and the group may have substituents other than an electron-withdrawing group. In an aromatic hydrocarbon group having electron-withdrawing groups, the number of electron-withdrawing groups in the aromatic hydrocarbon group is usually 1 to 20, preferably 1 to 10, more preferably 1 to 7, even more preferably 1 to 5, and particularly preferably 1 to 3. Examples of electron-withdrawing groups include alkyl groups having a fluorine atom as a substituent, fluorine atoms, cyano groups, nitro groups, acyl groups, and carboxyl groups, preferably cyano groups, alkyl groups having a fluorine atom as a substituent, or fluorine atoms, and more preferably cyano groups. Preferably, alkyl groups having a fluorine atom as a substituent are trifluoromethyl, pentafluoroethyl, perfluorobutyl, perfluorohexyl, or perfluorooctyl groups. In the aromatic hydrocarbon group having an electron-withdrawing group, the aromatic hydrocarbon group is preferably a monocyclic or bicyclic to hexacyclic aromatic hydrocarbon from which one or more hydrogen atoms directly bonded to the atoms constituting the ring have been removed, as this results in better luminescence efficiency of the light-emitting element of this embodiment. More preferably, it is a monocyclic, bicyclic, or tricyclic aromatic hydrocarbon from which one or more hydrogen atoms directly bonded to the atoms constituting the ring have been removed. Even more preferably, it is a monocyclic aromatic hydrocarbon from which one or more hydrogen atoms directly bonded to the atoms constituting the ring have been removed. These groups may have substituents. The aromatic hydrocarbon group in the electron-withdrawing aromatic hydrocarbon group is preferably a group obtained by removing one or more hydrogen atoms directly bonded to the ring-constituting atoms from benzene, naphthalene, anthracene, phenanthrene, dihydrophenanthrene, or fluorene, as this further improves the luminescence efficiency of the light-emitting element of this embodiment. More preferably, it is a group obtained by removing one or more hydrogen atoms directly bonded to the ring-constituting atoms from benzene, naphthalene, or fluorene, and even more preferably, it is a group obtained by removing one or more hydrogen atoms directly bonded to the ring-constituting atoms from benzene. These groups may have substituents.

[0079] Ar T2 In an aromatic hydrocarbon group containing a -C(=O)- group within the ring, the number of -C(=O)- groups constituting the ring is usually 1 to 10, preferably 1 to 7, more preferably 1 to 5, and even more preferably 1 to 3. Ar T2In this context, aromatic hydrocarbon groups containing a group represented by -C(=O)- in the ring include aromatic hydrocarbon groups containing a group represented by -C(=O)- in the ring, as described in the section on aromatic hydrocarbon groups above, preferably groups obtained by removing one or more hydrogen atoms directly bonded to the atoms constituting the ring from a bicyclic or tricyclic aromatic hydrocarbon containing a group represented by -C(=O)- in the ring, more preferably groups obtained by removing one or more hydrogen atoms directly bonded to the atoms constituting the ring from naphthoquinone, anthraquinone, phenanthrenequinone, indenone, fluorenone, or tetralone, and even more preferably groups obtained by removing one or more hydrogen atoms directly bonded to the atoms constituting the ring from anthraquinone, phenanthrenequinone, or fluorenone, and these groups may have substituents.

[0080] Ar T2 In this context, a "heterocyclic group containing at least one group selected from the group consisting of a group represented by =N-, a group represented by -C(=O)-, a group represented by -S(=O)-, and a group represented by -S(=O)2- (hereinafter also referred to as an "acceptor-type heterocyclic group")" is defined as a group containing at least one group selected from the group consisting of a group represented by =N-, a group represented by -C(=O)-, and a group represented by -S(=O)- This refers to a heterocyclic compound (hereinafter also called an "acceptor-type heterocyclic compound") that contains at least one group selected from the group consisting of a group represented by -N-, a group represented by -C(=O)-, a group represented by -S(=O)-, and a group represented by -S(=O)2-, from which one or more hydrogen atoms directly bonded to the atoms constituting the ring have been removed. Examples of acceptor-type heterocyclic compounds include heterocyclic compounds described in the section on heterocyclic groups above, in which the ring contains at least one group selected from the group consisting of a group represented by =N-, a group represented by -C(=O)-, a group represented by -S(=O)-, and a group represented by -S(=O)2-. The group obtained by removing one or more hydrogen atoms directly bonded to the atoms constituting the ring from the acceptor-type heterocyclic compound may have substituents.

[0081] In acceptor-type heterocyclic compounds, the total number of groups constituting the ring, represented by =N-, -C(=O)-, -S(=O)-, and -S(=O)2-, is usually 1 to 20, preferably 1 to 10, more preferably 1 to 5, and even more preferably 1 to 3. In acceptor-type heterocyclic compounds, the number of carbon atoms constituting the ring is usually 1 to 60, preferably 2 to 40, more preferably 2 to 20, and even more preferably 2 to 12. In acceptor-type heterocyclic compounds, the number of heteroatoms constituting the ring is usually 1 to 30, preferably 1 to 10, more preferably 1 to 5, and even more preferably 1 to 3.

[0082] The acceptor-type heterocyclic compound is preferably an aromatic heterocyclic compound because it provides superior luminescence efficiency to the light-emitting element of this embodiment. The acceptor-type heterocyclic compound is preferable because it provides better luminescence efficiency for the light-emitting element of this embodiment. Preferably, the heterocyclic compound contains at least one group selected from the group consisting of a group represented by =N-, a group represented by -C(=O)-, and a group represented by -S(=O)2- within the ring, and more preferably, the heterocyclic compound contains a group represented by =N- within the ring. The acceptor-type heterocyclic compound is preferably a monocyclic or 2- to 7-cyclic heterocyclic compound, more preferably a monocyclic or 2- to 5-cyclic heterocyclic compound, even more preferably a monocyclic, 2-cyclic, or 3-cyclic heterocyclic compound, and particularly preferably a monocyclic heterocyclic compound, as it provides a superior driving voltage for the light-emitting element of this embodiment. Acceptor-type heterocyclic compounds are preferable because they provide better luminescence efficiency to the light-emitting element of this embodiment, and therefore are preferably heterocyclic compounds containing a 5-membered ring or a 6-membered ring. Examples of acceptor-type heterocyclic compounds containing a 5-membered ring or a 6-membered ring include the acceptor-type heterocyclic compounds containing a 5-membered ring or a 6-membered ring exemplified in the section on heterocyclic groups above.

[0083] The acceptor-type heterocyclic group is preferable because it further improves the luminescence efficiency of the light-emitting element of this embodiment. Preferably, it is a group obtained by removing one or more hydrogen atoms directly bonded to the ring-constituting atoms (preferably carbon atoms) from diazole, triazole, oxadiazole, thiadiazole, pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, dibenzothiophene dioxide, dibenzothiophene oxide, dibenzopyranone, azaanthracene, diazaanthracene, azaphenanthrene, diazanthhrene, azacarbazole, diazacarbazole, or acridone. More preferably, it is a group obtained by removing one or more hydrogen atoms directly bonded to the ring-constituting atoms (preferably carbon atoms) from triazole, oxadiazole, thiadiazole, pyridine, diazabenzene, triazine, azaanthracene, diazanaphthalene, dibenzothiophene dioxide, dibenzopyranone, azaanthracene, diazaanthracene, azacarbazole, diazacarbazole, or acridone. More preferably, it is a group obtained by removing one or more hydrogen atoms directly bonded to the ring-constituting atoms (preferably carbon atoms) from triazole, oxadiazole, thiadiazole, pyridine, triazine, azacarbazole, thiadiazole, pyridine, diazanaphthalene, diazanaphthalene, dibenzothiophene dioxide, dibenzopyranone, azaanthracene, diazaanthracene, azacarbazole, diazacarbazole, or acridone. The group is obtained by removing one or more hydrogen atoms directly bonded to an atom constituting the ring (preferably a carbon atom) from din, diazabenzene, triazine, dibenzothiophene dioxide, dibenzothiophene oxide, or dibenzopyranone; more preferably, the group is obtained by removing one or more hydrogen atoms directly bonded to an atom constituting the ring (preferably a carbon atom) from triazole, oxadiazole, thiadiazole, pyridine, diazabenzene, triazine, or dibenzopyranone; particularly preferably, the group is obtained by removing one or more hydrogen atoms directly bonded to an atom constituting the ring from triazole, pyridine, diazabenzene, or triazine; these groups may have substituents.

[0084] Ar T2 The light-emitting element of this embodiment is more luminous, so preferably it is a group represented by -C(=O)-, a group represented by -S(=O)2-, an aromatic hydrocarbon group having an electron-withdrawing group, or an acceptor-type heterocyclic group, more preferably a group represented by -S(=O)2-, an aromatic hydrocarbon group having an electron-withdrawing group, or an acceptor-type heterocyclic group, and even more preferably a group represented by -S(=O)2- or an acceptor-type heterocyclic group, and these groups may have substituents. Ar T2Preferably, the light-emitting element of this embodiment has even better luminescence efficiency, and therefore preferably it is a group represented by -C(=O)-, a group represented by -S(=O)2-, an aromatic hydrocarbon group having an electron-withdrawing group, or a heterocyclic group containing at least one group selected from the group consisting of a group represented by =N-, a group represented by -C(=O)-, and a group represented by -S(=O)2- in the ring; more preferably it is a group represented by -S(=O)2-, an aromatic hydrocarbon group having an electron-withdrawing group, or a heterocyclic group containing at least one group selected from the group consisting of a group represented by =N- and a group represented by -C(=O)- in the ring; and even more preferably it is a group represented by -S(=O)2-, or a heterocyclic group containing a group represented by =N- in the ring, and these groups may have substituents.

[0085] Ar T2 The substituents that may be present are preferably halogen atoms, cyano groups, alkyl groups, cycloalkyl groups, alkoxy groups, cycloalkoxy groups, aryl groups, aryloxy groups, monovalent heterocyclic groups, or electron-withdrawing groups; more preferably alkyl groups, cycloalkyl groups, alkoxy groups, cycloalkoxy groups, aryl groups, monovalent heterocyclic groups, or electron-withdrawing groups; even more preferably alkyl groups, cycloalkyl groups, aryl groups, monovalent heterocyclic groups, or electron-withdrawing groups; and particularly preferably alkyl groups, cycloalkyl groups, aryl groups, or electron-withdrawing groups, and these groups may further have substituents.

[0086] Ar T2 Examples and preferred ranges of aryl groups in substituents that may be present are Ar T1 The examples and preferred ranges of aryl groups in substituents that may be present are the same as those mentioned above. Ar T2 The monovalent heterocyclic group in the substituent that may be present is Ar T1 The examples and preferred range of monovalent heterocyclic groups in substituents that may be present are the same, but among them, it is preferable that they be monovalent heterocyclic groups other than monovalent donor-type heterocyclic groups, and such groups may have further substituents. T2The monovalent heterocyclic group in the substituent that may be present is, for example, a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from a monocyclic or bicyclic to hexacyclic heterocyclic compound, preferably from the heterocyclic groups described in the section on heterocyclic groups above (preferably a heterocyclic group other than a monovalent donor-type heterocyclic group), more preferably a group obtained by removing one or more hydrogen atoms directly bonded to an atom constituting the ring from a monocyclic, bicyclic or tricyclic heterocyclic compound (preferably a heterocyclic group other than a monovalent donor-type heterocyclic group), and even more preferably furan, thiophene, oxadiazole, thiadiazole, diazole, triazole, pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, benzofuran, benzothiophene, azaindole, diazain The group is obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from doll, benzodiazole, benzotriazole, dibenzofuran, dibenzothiophene, azacarbazole, diazacarbazole, acridone, azaanthracene, diazaanthracene, azaphenanthrene, or diazaphenanthrene, and is particularly preferably a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, dibenzofuran, dibenzothiophene, azacarbazole, or diazacarbazole, and is especially preferably a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from pyridine, diazabenzene, or triazine, and these groups may further have substituents. Ar T2 Examples and preferred ranges of substituted amino groups in substituents that may be present are A r T1 The examples and preferred ranges of substituted amino groups in substituents that may be present are the same as those mentioned above. Ar T2 Examples and preferred ranges of substituents that may or may have are Ar T1 The substituents that may be present are the same as the examples and preferred ranges of substituents that may further be present.

[0087] Ar T1 and L T1This means that a ring may be formed by direct bonding or by bonding via a divalent group, but it is preferable that no ring is formed because the synthesis of the compound represented by formula (T-1) is easy. T1 and L T1 Examples and preferred ranges of divalent groups in cases where these groups are bonded via a divalent group to form a ring include Ar T1 The examples and preferred ranges of divalent groups are the same as those in the case where multiple divalent groups exist and are bonded to each other via divalent groups to form a ring. Ar T2 and L T1 This means that a ring may be formed by direct bonding or by bonding via a divalent group, but it is preferable that no ring is formed because the synthesis of the compound represented by formula (T-1) is easy. T2 and L T1 Examples and preferred ranges of divalent groups in cases where these groups are bonded via a divalent group to form a ring include Ar T1 The examples and preferred ranges of divalent groups are the same as those in the case where multiple divalent groups exist and are bonded to each other via divalent groups to form a ring. Ar T1 and Ar T2 This means that a ring may be formed by direct bonding or by bonding via a divalent group, but it is preferable that no ring is formed because the synthesis of the compound represented by formula (T-1) is easy. T1 and Ar T2 Examples and preferred ranges of divalent groups in cases where these groups are bonded via a divalent group to form a ring include Ar T1 The examples and preferred ranges of divalent groups are the same as those in the case where multiple divalent groups exist and are bonded to each other via divalent groups to form a ring. Ar T1 and R T1 ' may form a ring by direct bonding or by bonding via a divalent group, but it is preferable not to form a ring because the synthesis of the compound represented by formula (T-1) is easy. T1 and R T1 Examples and preferred ranges of divalent groups in cases where 'and are bonded via a divalent group to form a ring are Ar T1The examples and preferred ranges of divalent groups are the same as those in the case where multiple divalent groups exist and are bonded to each other via divalent groups to form a ring. Ar T2 and R T1 ' may form a ring by direct bonding or by bonding via a divalent group, but it is preferable not to form a ring because the synthesis of the compound represented by formula (T-1) is easy. T2 and R T1 Examples and preferred ranges of divalent groups in cases where 'and are bonded via a divalent group to form a ring are Ar T1 The examples and preferred ranges of divalent groups are the same as those in the case where multiple divalent groups exist and are bonded to each other via divalent groups to form a ring.

[0088] Examples of compounds represented by formula (T-1) include those represented by the following formula. Note that in the formula, Z 1 Z represents a group represented by -N= or a group represented by -CH=. However, in each of the compounds represented by the following formulas listed as compounds represented by formula (T-1), Z 1 At least one of them represents a base represented by -N=. 2 Z represents an oxygen atom or a sulfur atom. 3 This represents a group represented by -C(=O)- or -S(=O)2-. 1 , Z 2 and Z 3 If multiple instances exist, they may be identical or different. [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka]

[0089] The first layer contains two or more compounds represented by formula (T-1), allowing multiple compounds represented by formula (T-1) to interact with each other physically, chemically, or electrically. This interaction is thought to improve the light emission characteristics, charge transport characteristics, or charge injection characteristics of the light-emitting element of this embodiment, resulting in excellent luminescence efficiency.

[0090] [Fluorescent compounds] A "fluorescent compound" refers to a compound that exhibits fluorescence at room temperature. Preferably, a fluorescent compound is a compound that exhibits luminescence from a singlet excited state at room temperature.

[0091] ΔE of fluorescent compounds STThe ΔE of the fluorescent compound is usually greater than 0.50 eV, preferably 0.55 eV or more, more preferably 0.60 eV or more, even more preferably 0.65 eV or more, and particularly preferably 0.70 eV or more. ST The ΔE of the fluorescent compound is preferably 2.5 eV or less, more preferably 2.0 eV or less, even more preferably 1.5 eV or less, and particularly preferably 1.0 eV or less. ST Since the light-emitting element of this embodiment has excellent luminescence efficiency, it is preferably 0.55 eV to 2.5 eV, more preferably 0.60 eV to 2.0 eV, even more preferably 0.65 eV to 1.5 eV, and particularly preferably 0.70 eV to 1.0 eV.

[0092] The fluorescent luminescent compound is preferably a compound represented by formula (B) because it provides excellent luminescence efficiency to the light-emitting element of this embodiment.

[0093] (The compound represented by formula (B)) n 1B is preferably an integer from 1 to 8, more preferably an integer from 1 to 6, even more preferably an integer from 1 to 4, and particularly preferably 2.

[0094] Ar 1B In this case, the number of carbon atoms in the aromatic hydrocarbon group of the fused ring is usually 7 to 60, preferably 8 to 40, more preferably 9 to 30, and even more preferably 10 to 20, not including the number of carbon atoms of substituents.

[0095] Ar 1BExamples of the aromatic hydrocarbon group of the condensed ring in [description] include, for example, naphthalene ring, anthracene ring, phenanthrene ring, dihydrophenanthrene ring, triphenylene ring, naphthacene ring, fluorene ring, spirobifluorene ring, pyrene ring, perylene ring, chrysene ring, indene ring, fluoranthene ring, benzofluoranthene ring or acenaphthofluoranthene ring, and groups obtained by removing one or more hydrogen atoms directly bonded to the carbon atoms constituting the ring. Since the light-emitting element of this embodiment has excellent luminous efficiency, preferably naphthalene ring, anthracene ring, phenanthrene ring, dihydrophenanthrene ring, triphenylene ring, naphthacene ring, fluorene ring, spirobifluorene ring, pyrene ring, perylene ring, chrysene ring, fluoranthene ring, benzofluoranthene ring or acenaphthofluoranthene ring, and groups obtained by removing one or more hydrogen atoms directly bonded to the carbon atoms constituting the ring; more preferably naphthalene ring, anthracene ring, phenanthrene ring, triphenylene ring, naphthacene ring, pyrene ring, perylene ring or chrysene ring, and groups obtained by removing one or more hydrogen atoms directly bonded to the carbon atoms constituting the ring; still more preferably anthracene ring, naphthacene ring, pyrene ring or perylene ring, and groups obtained by removing one or more hydrogen atoms directly bonded to the carbon atoms constituting the ring; particularly preferably anthracene ring, and groups obtained by removing one or more hydrogen atoms directly bonded to the carbon atoms constituting the ring. These groups may have substituents.

[0096] Ar 1B Examples of the substituents that [group] may have are preferably halogen atoms, cyano groups, aryloxy groups or amino groups, more preferably fluorine atoms or cyano groups, and these groups may further have substituents.

[0097] Ar 1B Examples and preferred ranges of the substituents that the substituents that [group] may have may further have are the same as those of the substituents that R 1B may have, which will be described later.

[0098] R 1BSince the light-emitting element of the present embodiment has excellent luminous efficiency, it is preferably an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, a monovalent heterocyclic group, a substituted amino group, an alkenyl group or a cycloalkenyl group, more preferably an alkyl group, a cycloalkyl group, an aryl group, a monovalent heterocyclic group or a substituted amino group, still more preferably an alkyl group, an aryl group or a substituted amino group, particularly preferably a substituted amino group, and these groups may have substituents.

[0099] R 1B The number of carbon atoms of the aryl group in R, excluding the number of carbon atoms of the substituent, is usually 6 to 60, preferably 6 to 40, more preferably 6 to 30, and still more preferably 6 to 14.

[0100] R 1B Examples of the aryl group in R include a group obtained by removing one hydrogen atom directly bonded to a carbon atom constituting the ring from a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a dihydrophenanthrene ring, a triphenylene ring, a naphthacene ring, a fluorene ring, a spirobifluorene ring, a pyrene ring, a perylene ring, a chrysene ring, an indene ring, a fluoranthene ring, a benzofluoranthene ring or an acenaphthofluoranthene ring. Preferably, it is a group obtained by removing one hydrogen atom directly bonded to a carbon atom constituting the ring from a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a dihydrophenanthrene ring, a fluorene ring, a spirobifluorene ring, a pyrene ring, a fluoranthene ring or a benzofluoranthene ring. More preferably, it is a group obtained by removing one hydrogen atom directly bonded to a carbon atom constituting the ring from a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a fluorene ring, a spirobifluorene ring or a pyrene ring. Still more preferably, it is a group obtained by removing one hydrogen atom directly bonded to a carbon atom constituting the ring from a benzene ring, a naphthalene ring or an anthracene ring. Particularly preferably, it is a phenyl group, and these groups may further have substituents.

[0101] R 1BThe number of carbon atoms in the monovalent heterocyclic group in this compound is usually 2 to 60, preferably 3 to 30, and more preferably 3 to 20, not including the number of carbon atoms in the substituents.

[0102] R 1B Examples of monovalent heterocyclic groups in include pyrrole rings, diazole rings, triazole rings, pyridine rings, diazabenzene rings, triazine rings, azananaphthalene rings, diazananaphthalene rings, triazanaphthalene rings, indole rings, carbazole rings, azacarbazole rings, diazacarbazole rings, dibenzofuran rings, dibenzothiophene rings, phenoxazine rings, phenothiazine rings, acridine rings, 9,10-dihydroacridine rings, acridone rings, phenazine rings, and 5,10-dihydrophenazine rings, from which one hydrogen atom directly bonded to a carbon or heteroatom constituting the ring has been removed. Preferably, pyridine rings, diazabenzene rings, triazine rings, azananaphthalene rings, diazananaphthalene rings, carbazole rings, and azacarbazole rings are used. The group is obtained by removing one hydrogen atom directly bonded to a carbon atom or heteroatom constituting the ring from a ring, diazacarbazole ring, dibenzofuran ring, dibenzothiophene ring, phenoxazine ring, phenothiazine ring, 9,10-dihydroacridine ring, or 5,10-dihydrophenazine ring; more preferably, it is obtained by removing one hydrogen atom directly bonded to a carbon atom or heteroatom constituting the ring from a pyridine ring, diazabenzene ring, triazine ring, azananaphthalene ring, diazanaphthalene ring, carbazole ring, dibenzofuran ring, or dibenzothiophene ring; even more preferably, it is obtained by removing one hydrogen atom directly bonded to a carbon atom constituting the ring from a dibenzofuran ring or dibenzothiophene ring; these groups may further have substituents.

[0103] R 1B In the substituted amino group in , the substituents on the amino group are preferably aryl groups or monovalent heterocyclic groups, more preferably aryl groups, and these groups may have further substituents. Examples and preferred ranges of aryl groups in the substituents on the amino group are given by R 1BThe examples and preferred ranges of aryl groups are the same as in R. Examples and preferred ranges of monovalent heterocyclic groups in substituents of the amino group are R 1B The examples and preferred ranges of monovalent heterocyclic groups are the same as those in [the relevant section].

[0104] R 1B The substituents that may be present are preferably alkyl groups, cycloalkyl groups, alkoxy groups, cycloalkoxy groups, aryl groups, monovalent heterocyclic groups, substituted amino groups, or halogen atoms; more preferably alkyl groups, cycloalkyl groups, aryl groups, monovalent heterocyclic groups, or substituted amino groups; even more preferably alkyl groups, cycloalkyl groups, or aryl groups; particularly preferably alkyl groups or cycloalkyl groups, and these groups may have further substituents.

[0105] R 1B Examples and preferred ranges of aryl groups, monovalent heterocyclic groups, and substituted amino groups in substituents that may be present are, respectively, R 1B The examples and preferred ranges of aryl groups, monovalent heterocyclic groups, and substituted amino groups are the same as those in the above.

[0106] R 1B The substituents that the group may have may further have are preferably alkyl groups, cycloalkyl groups, alkoxy groups, cycloalkoxy groups, aryl groups, monovalent heterocyclic groups, substituted amino groups, or halogen atoms, more preferably alkyl groups, cycloalkyl groups, aryl groups, or monovalent heterocyclic groups, and even more preferably alkyl groups or cycloalkyl groups, and these groups may further have substituents.

[0107] R 1B Examples and preferred ranges of aryl groups, monovalent heterocyclic groups, and substituted amino groups in substituents that may or may have are, respectively, R 1B The examples and preferred ranges of aryl groups, monovalent heterocyclic groups, and substituted amino groups are the same as those in the above.

[0108] R 1BWhen there are a plurality of them, it is preferable that they are combined with each other and do not form a ring together with the atoms to which each is attached.

[0109] Examples of the fluorescent compound represented by the formula (B) include compounds represented by the following formulas.

[0110] [Chemical formula] [Chemical formula] [Chemical formula] [Chemical formula] [Chemical formula] [Chemical formula] [Chemical formula] [Chemical formula] [Chemical formula]

[0111] [First composition] The first layer may contain a composition (hereinafter also referred to as "the first composition") comprising a fluorescent compound, two or more compounds T that satisfy at least one of requirements (i) and (ii), and at least one selected from the group consisting of hole transport materials, hole injection materials, electron transport materials, electron injection materials, luminescent materials, and antioxidants. However, in the first composition, the hole transport material, hole injection material, electron transport material, electron injection material, and luminescent material are different from the fluorescent compound and the compounds T that satisfy at least one of requirements (i) and (ii).

[0112] (Hole transport material) Hole transport materials are classified into low-molecular-weight compounds and high-molecular-weight compounds. Hole transport materials may also have crosslinking groups. Examples of low molecular weight compounds include triphenylamine and its derivatives, N,N'-di-1-naphthyl-N,N'-diphenylbenzidine (α-NPD), and aromatic amine compounds such as N,N'-diphenyl-N,N'-di(m-tolyl)benzidine (TPD). Examples of polymer compounds include polyvinylcarbazole and its derivatives; and polyarylene and its derivatives having aromatic amine structures in the side chain or main chain. The polymer compound may also be a compound to which an electron-accepting site is attached. Examples of electron-accepting sites include fullerene, tetrafluorotetracyanoquinodimethane, tetracyanoethylene, and trinitrofluorenone.

[0113] In the first composition, if a hole transport material is included, the amount of the hole transport material is usually 1 to 400 parts by mass, preferably 5 to 150 parts by mass, when the total of the fluorescent compound and all compounds T is 100 parts by mass. The hole transport material may be used alone or in combination of two or more types.

[0114] (electron transport material) Electron transport materials are classified into low-molecular-weight compounds and high-molecular-weight compounds. Electron transport materials may also contain crosslinking groups. Examples of low molecular weight compounds include metal complexes with 8-hydroxyquinoline as a ligand, oxadiazoles, anthraquinodimethanes, benzoquinones, naphthoquinones, anthraquinones, tetracyanoanthraquinodimethanes, fluorenones, diphenyldicyanoethylenes and diphenoquinones, and their derivatives. Examples of polymer compounds include polyphenylene, polyfluorene, and their derivatives. The polymer compounds may be metal-doped.

[0115] In the first composition, if an electron transport material is included, the amount of electron transport material is usually 1 to 400 parts by mass, preferably 5 to 150 parts by mass, when the total of the fluorescent compound and all compounds T is 100 parts by mass. Electron transport materials may be used individually or in combination of two or more types.

[0116] (Hole injection materials and electron injection materials) Hole injection materials and electron injection materials are classified into low-molecular-weight compounds and high-molecular-weight compounds, respectively. Hole injection materials and electron injection materials may also have crosslinking groups. Examples of low molecular weight compounds include metal phthalocyanines such as copper phthalocyanine; carbon; metal oxides such as molybdenum and tungsten; and metal fluorides such as lithium fluoride, sodium fluoride, cesium fluoride, and potassium fluoride. Examples of polymer compounds include polyaniline, polythiophene, polypyrrole, polyphenylene vinylene, polythienylene vinylene, polyquinoline and polyquinoxaline, and their derivatives; and conductive polymers such as polymers containing aromatic amine structures in the main chain or side chains.

[0117] If the first composition contains a hole injection material and / or an electron injection material, the amount of the hole injection material and the electron injection material is usually 1 to 400 parts by mass, preferably 5 to 150 parts by mass, when the total amount of the fluorescent compound and all compounds T is 100 parts by mass. The electron injection material and the hole injection material may be used individually or in combination of two or more types.

[0118] Ion doping When the hole injection material or electron injection material contains a conductive polymer, the electrical conductivity of the conductive polymer is preferably 1 × 10⁻⁶. -5 S / cm~1×10 3 The density is S / cm. To achieve this electrical conductivity within the conductive polymer range, an appropriate amount of ions can be doped into the conductive polymer. The type of ion used for doping depends on the material: anions for hole-injection materials and cations for electron-injection materials. Examples of anions include polystyrene sulfonate ions, alkylbenzene sulfonate ions, and camphor sulfonate ions. Examples of cations include lithium ions, sodium ions, potassium ions, and tetrabutylammonium ions. The doping ions may be used individually or in combination of two or more.

[0119] (Luminescent material) Luminescent materials are classified into low-molecular-weight compounds and high-molecular-weight compounds. Luminescent materials may also have crosslinking groups.

[0120] Examples of low molecular weight compounds include naphthalene and its derivatives, anthracene and its derivatives, perylene and its derivatives, and triplet luminescent complexes with iridium, platinum, or europium as the central metal. Examples of triplet-luminescent complexes include the following metal complexes.

[0121] [ka]

[0122] [ka]

[0123] [ka]

[0124] [ka]

[0125] [ka]

[0126] Examples of polymer compounds include polymer compounds containing phenylene groups, naphthalene diyl groups, anthracene diyl groups, fluororangeyl groups, phenanthrene diyl groups, dihydrophenanthrene diyl groups, groups represented by formula (X) described later, carbazole diyl groups, phenoxazine diyl groups, phenothiazine diyl groups, pyrendiyl groups, and the like.

[0127] In the first composition, if a luminescent material is included, the amount of the luminescent material is usually 0.1 to 400 parts by mass, preferably 5 to 150 parts by mass, when the total of the fluorescent compound and all compounds T is 100 parts by mass. The luminescent material may be used alone or in combination of two or more types.

[0128] (Antioxidant) The antioxidant can be any compound that is soluble in the same solvent as the fluorescent compound and compound T, and does not inhibit luminescence or charge transport. Examples include phenolic antioxidants and phosphorus-based antioxidants.

[0129] In the first composition, if an antioxidant is included, the amount of antioxidant is usually 0.001 to 10 parts by mass, when the total of the fluorescent compound and all compounds T is 100 parts by mass. Antioxidants may be used individually or in combination of two or more types.

[0130] [First Ink] The first layer can be formed, for example, using a composition (hereinafter also referred to as "first ink") containing a fluorescent compound, two or more compounds T that satisfy at least one of requirements (i) and (ii), and a solvent. The first ink can be suitably used to fabricate light-emitting elements using wet methods such as spin coating, casting, microgravure coating, gravure coating, bar coating, roll coating, wire bar coating, dip coating, spray coating, screen printing, flexographic printing, offset printing, inkjet printing, capillary coating, and nozzle coating.

[0131] The viscosity of the first ink can be adjusted depending on the type of coating method, but when applied to printing methods in which the solution passes through an ejection device, such as inkjet printing, it is preferably 1 to 20 mPa·s at 25°C, as this reduces clogging and deviation during ejection.

[0132] The solvent contained in the first ink is preferably a solvent that can dissolve or uniformly disperse the solid components in the ink. Examples of solvents contained in the first ink include: chlorine-based solvents such as 1,2-dichloroethane, 1,1,2-trichloroethane, chlorobenzene, and o-dichlorobenzene; ether-based solvents such as tetrahydrofuran, dioxane, anisole, and 4-methylanisole; aromatic hydrocarbon solvents such as toluene, xylene, mesitylene, ethylbenzene, n-hexylbenzene, and cyclohexylbenzene; and cyclohexane, methylcyclohexane, n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane, n-dodecane, and bicyclitium. Examples of solvents include aliphatic hydrocarbon solvents such as hexyl; ketone solvents such as acetone, methyl ethyl ketone, cyclohexanone, and acetophenone; ester solvents such as ethyl acetate, butyl acetate, ethyl cellulose acetate, methyl benzoate, and phenyl acetate; polyhydric alcohol solvents such as ethylene glycol, glycerin, and 1,2-hexanediol; alcohol solvents such as isopropyl alcohol and cyclohexanol; sulfoxide solvents such as dimethyl sulfoxide; and amide solvents such as N-methyl-2-pyrrolidone and N,N-dimethylformamide. The solvent may be used alone or in combination of two or more types.

[0133] In the first ink, the amount of solvent is usually 1,000 to 100,000 parts by mass, preferably 2,000 to 20,000 parts by mass, when the total amount of the fluorescent compound and all compounds T is 100 parts by mass.

[0134] <Second Layer> In the light-emitting element of this embodiment, the second layer is a layer containing a crosslinked compound having a crosslinking group. The second layer may contain only one type of crosslinked material, or it may contain two or more types.

[0135] In the light-emitting element of this embodiment, the number of crosslinked compounds containing crosslinking groups in the second layer is usually 1 to 10 types, preferably 1 to 5 types, more preferably 1 to 3 types, even more preferably 1 or 2 types, and particularly preferably 1 type, as this facilitates the manufacture of the light-emitting element of this embodiment.

[0136] In the second layer, the content of the crosslinked compound having a crosslinking group is limited to a range that allows the second layer to function as such. The content of the crosslinked compound having a crosslinking group in the second layer may be 1 to 100% by mass based on the total amount of the second layer, preferably 10 to 100% by mass, more preferably 30 to 100% by mass, even more preferably 50 to 100% by mass, and particularly preferably 70% by mass, as this provides a superior driving voltage for the light-emitting element of this embodiment. It is approximately 100% by mass, and particularly preferably 90-100% by mass.

[0137] [Cross-linked compounds containing cross-linking groups] A crosslinked compound of a crosslinking group can be obtained, for example, by crosslinking the compound having a crosslinking group using the methods and conditions described later. The compound having a crosslinking group may be a low-molecular-weight compound having a crosslinking group, or a high-molecular-weight compound having a crosslinking group.

[0138] In a compound having a crosslinking group, the crosslinking group is preferably at least one crosslinking group selected from group A of crosslinking groups (i.e., at least one crosslinking group selected from the crosslinking groups represented by formulas (XL-1) to (XL-19)), and more preferably (XL-1) to (XL-4), (XL-7) to (XL-10), or (XL-14) to (XL-19). The crosslinking group is represented by formula (XL-1), formula (XL-3), formula (XL-7), formula (XL-9), formula (XL-10), or formulas (XL-16) to (XL-19), and is particularly preferably represented by formula (XL-1), formula (XL-7), formula (XL-10), formula (XL-16), or formula (XL-17), and is especially preferably represented by formula (XL-1), formula (XL-10), formula (XL-16), or formula (XL-17). Examples and preferred ranges of substituents that may be present in a crosslinking group selected from group A are as follows: Y1 The examples and preferred ranges of substituents that the group represented by may have are the same. A compound having a crosslinking group may contain only one crosslinking group selected from group A, or it may contain two or more.

[0139] (Polymer compounds containing crosslinking groups) It is preferable to include the crosslinking group as a structural unit having a crosslinking group in the polymer compound having a crosslinking group, since the crosslinking properties of the polymer compound having a crosslinking group are superior and the luminescence efficiency of the light-emitting element of this embodiment is superior. In other words, it is preferable that the polymer compound having a crosslinking group is a polymer compound that contains a structural unit having a crosslinking group. Examples and preferred ranges of crosslinking groups in polymer compounds having crosslinking groups and structural units having crosslinking groups are the same as examples and preferred ranges of crosslinking groups in compounds having crosslinking groups. When a polymer compound having a crosslinking group contains a structural unit having a crosslinking group, the content of the structural unit having a crosslinking group should be within a range that allows the polymer compound to function as a polymer compound having a crosslinking group. When a polymer compound having a crosslinking group contains a structural unit having a crosslinking group, the content of the structural unit having a crosslinking group should be, for example, 0.1 to 100 mol% of the total content of structural units contained in the polymer compound having a crosslinking group, preferably 1 to 99 mol%, more preferably 2 to 90 mol%, even more preferably 3 to 70 mol%, and particularly preferably 5 to 50 mol% in relation to the total content of structural units contained in the polymer compound having a crosslinking group, which provides superior crosslinking properties of the polymer compound and superior luminescence efficiency of the light-emitting element of this embodiment. The structural unit having a crosslinking group may be present as one type or as two or more types in the polymer compound having a crosslinking group.

[0140] The structural unit having a crosslinking group is preferably a structural unit represented by formula (Z) or formula (Z') because it provides better luminescence efficiency to the light-emitting element of this embodiment.

[0141] • Constituent units represented by formula (Z) n is usually an integer from 1 to 10, and is preferably an integer from 1 to 7, more preferably an integer from 1 to 4, even more preferably 1 or 2, and particularly preferably 2, as this provides better luminous efficiency for the light-emitting element of this embodiment. nA is usually an integer between 0 and 10, and is preferably an integer between 0 and 7, more preferably an integer between 0 and 4, and even more preferably an integer between 0 and 2, as this provides better luminous efficiency for the light-emitting element of this embodiment.

[0142] Ar 3 Examples of hydrocarbon groups in this context include aromatic hydrocarbon groups which may have substituents and aliphatic hydrocarbon groups which may have substituents. 3 The hydrocarbon groups in this context include groups formed by the bonding of multiple such groups.

[0143] Ar 3Examples of aliphatic hydrocarbon groups in this context include alkylene groups or cycloalkylene groups from which n hydrogen atoms have been removed, preferably alkylene groups from which n hydrogen atoms have been removed, and these groups may have substituents.

[0144] Ar 3 Examples of aromatic hydrocarbon groups in this context include groups obtained by removing n hydrogen atoms from an arylene group, and these groups may have substituents. Examples and preferred ranges of this arylene group are described later in the Ar Y1 Examples and preferred ranges of arylene groups in this context are given.

[0145] Ar 3 Examples of heterocyclic groups in this context include groups obtained by removing n hydrogen atoms from a divalent heterocyclic group, and these groups may have substituents. Examples and preferred ranges of these divalent heterocyclic groups include Ar, which will be described later. Y1 Examples and preferred ranges of divalent heterocyclic groups in this context are given.

[0146] Ar 3 Examples and preferred ranges of the hydrocarbon group and heterocyclic group in a group in which at least one hydrocarbon group and at least one heterocyclic group are directly bonded are, respectively, Ar 3 The examples and preferred ranges of hydrocarbon groups and heterocyclic groups are the same as those in the above. Ar 3 Examples of groups in which at least one hydrocarbon group and at least one heterocyclic group are directly bonded include, for example, Ar, which will be described later. Y1 Examples include a divalent group obtained by removing n hydrogen atoms from a group in which at least one arylene group and at least one divalent heterocyclic group are directly bonded.

[0147] Ar 3 The light-emitting element of this embodiment is preferably a hydrocarbon group or a heterocyclic group, more preferably a hydrocarbon group, and even more preferably an aromatic hydrocarbon group, as this provides superior luminescence efficiency. These groups may have substituents.

[0148] L AExamples and preferred ranges of arylene groups represented by Ar are described below. Y1 Examples and preferred ranges of arylene groups represented by are given, and since the light-emitting device of this embodiment has better luminescence efficiency, L A The arylene group represented by is preferably a phenylene group or a fluoroorangeyl group, and these groups may have substituents.

[0149] L A Examples and preferred ranges of divalent heterocyclic groups represented by are shown below in Ar Y1 The examples and preferred ranges of divalent heterocyclic groups represented by are the same.

[0150] L A The group is preferably an arylene group or an alkylene group, more preferably a phenylene group, a fluoroorangeyl group, or an alkylene group, as this facilitates the synthesis of the polymer compound of the second layer, and these groups may have substituents.

[0151] R' is preferably an aryl group or a monovalent heterocyclic group, more preferably an aryl group, and these groups may have substituents. Examples and preferred ranges of aryl groups and monovalent heterocyclic groups in R' are given below. Y1 The examples and preferred ranges of aryl groups and monovalent heterocyclic groups in substituents that may be present are the same as those mentioned above.

[0152] Ar 3 , L A Examples and preferred ranges of substituents that the group represented by and R' may have are given below in Ar Y1 The examples and preferred ranges of substituents that the group represented by may have are the same. Examples and preferred ranges of crosslinking groups in X are the same as examples and preferred ranges of crosslinking groups in compounds having crosslinking groups.

[0153] The constituent unit represented by formula (Z) exhibits excellent stability and crosslinkability in polymer compounds containing the constituent unit having a crosslinking group. Therefore, the constituent unit is preferably present in an amount of 0.5 to 80 mol%, more preferably 3 to 65 mol%, and even more preferably 5 to 50 mol%, relative to the total amount of constituent units contained in the polymer compound containing the constituent unit having a crosslinking group. The constituent unit represented by formula (Z) may be present as one type or as two or more types in a polymer compound containing a constituent unit having a crosslinking group.

[0154] · Constituent units represented by equation (Z') mA is usually an integer between 0 and 10, and is preferably an integer between 0 and 7, more preferably an integer between 0 and 4, even more preferably an integer between 0 and 2, particularly preferably 0 or 1, and especially preferably 0, as this provides better luminous efficiency for the light-emitting element of this embodiment. m is usually an integer between 0 and 10, and is preferably an integer between 0 and 7, more preferably an integer between 0 and 4, and even more preferably an integer between 0 and 2, as this provides better luminescence efficiency for the light-emitting element of this embodiment. c is usually an integer between 0 and 10, and is preferably an integer between 0 and 5, more preferably an integer between 0 and 2, even more preferably 0 or 1, and particularly preferably 0, as this facilitates the production of the polymer compound of the second layer and improves the luminescence efficiency of the light-emitting element of this embodiment.

[0155] Ar 5 Examples and preferred ranges of hydrocarbon groups and heterocyclic groups in Ar 3 The examples and preferred ranges of hydrocarbon groups and heterocyclic groups are the same as those in the above. Ar 5 Examples and preferred ranges of groups in which at least one hydrocarbon group and at least one heterocyclic group are directly bonded are Ar 3 The examples and preferred ranges of groups in which at least one hydrocarbon group and at least one heterocyclic group are directly bonded are the same as in the above. Ar 5The light-emitting element of this embodiment is preferably a hydrocarbon group or a heterocyclic group, more preferably a hydrocarbon group, and even more preferably an aromatic hydrocarbon group, as this provides superior luminescence efficiency. These groups may have substituents.

[0156] Ar 4 and Ar 6 Each of these is an arylene group that may preferably have substituents, as it provides better luminescence efficiency for the light-emitting element of this embodiment. Ar 4 and Ar 6 Examples and preferred ranges of arylene groups in Ar are described below. X1 Ar X2 Ar X3 and Ar X4 The examples and preferred ranges of arylene groups are the same as those in the above. Ar 4 and Ar 6 Examples and preferred ranges of divalent heterocyclic groups in are described below in Ar X1 Ar X2 Ar X3 and Ar X4 The examples and preferred ranges of divalent heterocyclic groups are the same as those in [the relevant section]. Ar 4 ~Ar 6 Examples and preferred ranges of substituents that the group represented by may have are, as described below, Ar Y1 The examples and preferred ranges of substituents that the group represented by may have are the same.

[0157] K A Examples and preferred ranges are L A This is the same as the example and preferred range. The examples and preferred ranges for R'' are the same as those for R'.

[0158] Examples and preferred ranges of crosslinking groups in X' are, It is the same as an enclosure. Examples and preferred ranges of aryl groups and monovalent heterocyclic groups in X' are given below in R X1 , RX2 and R X3 The examples and preferred ranges of aryl groups and monovalent heterocyclic groups are the same as those in [the relevant section]. X' is preferably a bridging group, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, more preferably a bridging group, an aryl group, or a monovalent heterocyclic group, and even more preferably a bridging group or an aryl group, and these groups may have substituents. Examples and preferred ranges of substituents that the group represented by X' may have are shown below in Ar Y1 The examples and preferred ranges of substituents that the group represented by may have are the same.

[0159] The constituent unit represented by formula (Z') exhibits excellent stability and crosslinkability in polymer compounds containing the constituent unit having a crosslinking group. Therefore, its concentration is preferably 0.5 to 50 mol%, more preferably 3 to 30 mol%, and even more preferably 5 to 20 mol%, relative to the total amount of constituent units contained in the polymer compound containing the constituent unit having a crosslinking group. The constituent unit represented by formula (Z') may be present as one type or as two or more types in a polymer compound containing a constituent unit having a crosslinking group.

[0160] Examples of structural units having a bridging group include the structural unit represented by the following formula. In the formula, Z 2 This expresses the same meaning as above. X A X represents a crosslinking group. A If multiple instances exist, they may be identical or different. A The examples and preferred ranges are the same as the preferred ranges for the crosslinking group in X.

[0161] [ka]

[0162] [ka]

[0163] [ka]

[0164] [ka]

[0165] [ka]

[0166] • Other constituent units The polymer compound having a crosslinking group is preferable to be a polymer compound (hereinafter also referred to as "polymer compound (2')") that contains at least one constituent unit selected from the group consisting of constituent units represented by formula (X) and constituent units represented by formula (Y), since the light-emitting device of this embodiment has better luminescence efficiency. The polymer compound (2') is a polymer compound that contains at least one structural unit selected from the group consisting of structural units represented by formula (X) and structural units represented by formula (Y), and also contains a structural unit having a crosslinking group. The polymer compound (2') is preferably a polymer compound comprising at least one structural unit selected from the group consisting of structural units represented by formula (X) and structural units represented by formula (Y), and a structural unit having a crosslinking group, since the light-emitting element of this embodiment has superior luminescence efficiency. In polymer compound (2'), it is preferable that the structural units having crosslinking groups are different from the structural units represented by formula (X) and formula (Y). The polymer compound (2') preferably contains the constituent unit represented by formula (Y) because it provides better luminescence efficiency to the light-emitting element of this embodiment. The polymer compound (2') is preferable to contain the constituent unit represented by formula (X) because it has excellent hole transport properties. The polymer compound (2') is preferable to include the constituent units represented by formula (X) and formula (Y) because it has excellent hole transport properties and provides superior luminescence efficiency for the light-emitting element of this embodiment.

[0167] [ka]

[0168] [In the formula, a X1 and a X2 Each of these independently represents a non-negative integer. Ar X1 and Ar X3 Each of these independently represents an arylene group or a divalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which they are bonded. Ar X2 and Ar X4 Each of these independently represents an arylene group, a divalent heterocyclic group, or a divalent group formed by the direct bonding of at least one arylene group and at least one divalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may bond to each other to form a ring with the atom to which they are bonded. X2 If multiple instances exist, they may be identical or different. X4 If multiple instances exist, they may be identical or different from one another. R X1 , R X2 and R X3 Each of these independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other, forming a ring with the atom to which each substituent is bonded. X2 If multiple instances exist, they may be identical or different. X3 If multiple instances exist, they may be identical or different.

[0169] [ka]

[0170] [In the formula, Ar Y1 This represents an arylene group, a divalent heterocyclic group, or a divalent group formed by the direct bonding of at least one arylene group and at least one divalent heterocyclic group, where these groups may have substituents. If multiple substituents exist, they may be identical or different, and may bond to each other, forming a ring with the atom to which each substituent is bonded.

[0171] When the polymer compound (2') contains a constituent unit represented by formula (X), the content of the constituent unit represented by formula (X) is usually 0.1 to 99 mol% of the total amount of constituent units contained in the polymer compound (2'), and is preferably 1 to 90 mol%, more preferably 5 to 80 mol%, even more preferably 10 to 70 mol%, and particularly preferably 20 to 60 mol%, as this provides excellent hole transport properties for the polymer compound (2') and further enhances the luminescence efficiency of the light-emitting element of this embodiment. The constituent unit represented by formula (X) may be present in the polymer compound (2') as one type or as two or more types.

[0172] When the polymer compound (2') contains a constituent unit represented by formula (Y), the content of the constituent unit represented by formula (Y) is usually 0.1 to 99 mol%, more preferably 0.5 to 95 mol%, more preferably 1 to 90 mol%, even more preferably 2 to 80 mol%, and particularly preferably 3 to 70 mol%, in order to obtain better luminescence efficiency from the light-emitting element of this embodiment. The constituent unit represented by formula (Y) may be present in the polymer compound (2') as one type or as two or more types.

[0173] • Constituent units represented by formula (Y) Ar Y1The arylene group represented by is preferably a group obtained by removing two hydrogen atoms directly bonded to the atoms constituting the ring from a monocyclic or bicyclic to hexacyclic aromatic hydrocarbon, more preferably a group obtained by removing two hydrogen atoms directly bonded to the atoms constituting the ring from a monocyclic, bicyclic, or tricyclic aromatic hydrocarbon, even more preferably a group obtained by removing two hydrogen atoms directly bonded to the atoms constituting the ring from benzene, naphthalene, anthracene, phenanthrene, dihydrophenanthrene, or fluorene, and particularly preferably a group obtained by removing two hydrogen atoms directly bonded to the atoms constituting the ring from benzene, phenanthrene, dihydrophenanthrene, or fluorene, and these may have substituents.

[0174] Ar Y1 The divalent heterocyclic group represented by is preferable to the light-emitting element of this embodiment because it provides better luminescence efficiency. Preferably, it is a monocyclic or bicyclic to hexacyclic heterocyclic group from which two hydrogen atoms directly bonded to the atoms constituting the ring have been removed. More preferably, it is a monocyclic, bicyclic, or tricyclic heterocyclic group from which two hydrogen atoms directly bonded to the atoms constituting the ring have been removed. Further preferable are pyridine, diazabenzene, triazine, azananaphthalene, diazananaphthalene, carbazole, dibenzofuran, dibenzothiophene, phenoxazine, phenothiazine, 9,1 These are groups obtained by removing two hydrogen atoms directly bonded to the ring-forming atoms (preferably carbon atoms or nitrogen atoms, more preferably carbon atoms) from 0-dihydroacridine or 5,10-dihydrophenazine, and particularly preferably groups obtained by removing two hydrogen atoms directly bonded to the ring-forming atoms (preferably carbon atoms or nitrogen atoms, more preferably carbon atoms) from pyridine, diazabenzene, triazine, carbazole, dibenzofuran, dibenzothiophene, phenoxazine, or phenothiazine, and these may have substituents.

[0175] Ar Y1 In a divalent group in which at least one arylene group and at least one divalent heterocyclic group are directly bonded, the preferred ranges for the arylene group and the divalent heterocyclic group are, respectively, Ar Y1This is the same as the preferred range for the arylene group and the divalent heterocyclic group represented by .

[0176] Ar Y1 In this context, "a divalent group in which at least one arylene group and at least one divalent heterocyclic group are directly bonded" includes, for example, groups represented by the following formula, which may have substituents.

[0177] [ka]

[0178] Ar Y1 It is preferable that the luminescence efficiency of the light-emitting element of this embodiment is better, and therefore it is preferable that the arylene group may have substituents.

[0179] Ar Y1 The substituents that the group represented by may have are preferably alkyl groups, cycloalkyl groups, alkoxy groups, cycloalkoxy groups, aryl groups, aryloxy groups, monovalent heterocyclic groups, substituted amino groups, or fluorine atoms; more preferably alkyl groups, cycloalkyl groups, alkoxy groups, cycloalkoxy groups, aryl groups, monovalent heterocyclic groups, or substituted amino groups; even more preferably alkyl groups, cycloalkyl groups, aryl groups, monovalent heterocyclic groups, or substituted amino groups; particularly preferably alkyl groups, cycloalkyl groups, or aryl groups; and these groups may have further substituents.

[0180] Ar Y1The aryl group in the substituent that the group represented by may have is preferably a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from a monocyclic or bicyclic to hexacyclic aromatic hydrocarbon ring, more preferably a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from a monocyclic, bicyclic or tricyclic aromatic hydrocarbon ring, even more preferably a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from benzene, naphthalene, anthracene, phenanthrene, dihydrophenanthrene, or fluorene, and particularly preferably a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from benzene, phenanthrene, dihydrophenanthrene, or fluorene, and these may further have substituents.

[0181] Ar Y1 The monovalent heterocyclic group in the substituent that the group represented by may have is preferably a monocyclic or bicyclic to hexacyclic heterocyclic group from which one hydrogen atom directly bonded to the atoms constituting the ring has been removed, as this results in better luminescence efficiency of the light-emitting element of this embodiment. More preferably, it is a monocyclic, bicyclic, or tricyclic heterocyclic group from which one hydrogen atom directly bonded to the atoms constituting the ring has been removed. The group is one from which one hydrogen atom directly bonded to an atom constituting the ring has been removed, and more preferably from pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, carbazole, dibenzofuran, dibenzothiophene, phenoxazine, phenothiazine, 9,10-dihydroacridine, or 5,10-dihydrophenazine, and particularly preferably from pyridine, diazabenzene, triazine, carbazole, dibenzofuran, dibenzothiophene, phenoxazine, or phenothiazine, and these may further have substituents.

[0182] Ar Y1In the substituted amino group in the substituent that the group represented by may have, the substituent of the amino group is preferably an aryl group or a monovalent heterocyclic group, more preferably an aryl group, and these groups may have further substituents. Examples and preferred ranges of aryl groups and monovalent heterocyclic groups in the substituent of the amino group are, respectively, Ar Y1 The examples and preferred ranges of aryl groups and monovalent heterocyclic groups in substituents that the group represented by may have are the same.

[0183] Ar Y1 The substituents that the group represented by may have may further have are preferably alkyl groups, cycloalkyl groups, alkoxy groups, cycloalkoxy groups, aryl groups, aryloxy groups, monovalent heterocyclic groups, substituted amino groups, or fluorine atoms, more preferably alkyl groups, cycloalkyl groups, aryl groups, monovalent heterocyclic groups, or substituted amino groups, even more preferably alkyl groups, cycloalkyl groups, or aryl groups, and particularly preferably alkyl groups or cycloalkyl groups. These groups may have further substituents, but it is preferable that they do not have further substituents. Ar Y1 Examples and preferred ranges of aryl groups, monovalent heterocyclic groups, and substituted amino groups in substituents that the group represented by may have or may have further substituents are, respectively, Ar Y1 The examples and preferred ranges of aryl groups, monovalent heterocyclic groups, and substituted amino groups in substituents that the group represented by may have are the same as those for aryl groups, monovalent heterocyclic groups, and substituted amino groups.

[0184] The constituent unit represented by formula (Y) is preferably the constituent unit represented by formula (Y-1) or formula (Y-2) because it provides better luminescence efficiency for the light-emitting element of this embodiment.

[0185] [ka]

[0186] [In the formula, R Y1R represents a hydrogen atom, alkyl group, cycloalkyl group, alkoxy group, cycloalkoxy group, aryl group, aryloxy group, monovalent heterocyclic group, substituted amino group, or fluorine atom, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other, forming a ring with the atom to which each is bonded. Y1 These atoms may be identical or different, and they may be bonded to each other, forming a ring with the atom they bond to. X Y1 -C(R Y2 )2-, -C(R Y2 )=C(R Y2 )- or -C(R Y2 )2-C(R Y2 ) Represents a group represented by 2-. Y2 represents a hydrogen atom, alkyl group, cycloalkyl group, alkoxy group, cycloalkoxy group, aryl group, aryloxy group, monovalent heterocyclic group, substituted amino group, or fluorine atom, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other, forming a ring with the atom to which each substituent is bonded. Y2 These atoms may be identical or different, and they may be bonded to each other, forming a ring with the atom they bond to.

[0187] R Y1 The group is preferably a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, a monovalent heterocyclic group, or a substituted amino group, more preferably a hydrogen atom, an alkyl group, a cycloalkyl group, or an aryl group, and even more preferably a hydrogen atom or an alkyl group, and these groups may have substituents.

[0188] In equation (Y-1), R Y1 at least one of (preferably R) Y1At least two of the elements are preferably alkyl groups, cycloalkyl groups, alkoxy groups, cycloalkoxy groups, aryl groups, aryloxy groups, monovalent heterocyclic groups, substituted amino groups, or fluorine atoms, as these have better luminescence efficiency than the light-emitting element of this embodiment; more preferably alkyl groups, cycloalkyl groups, aryl groups, monovalent heterocyclic groups, or substituted amino groups; even more preferably alkyl groups, cycloalkyl groups, or aryl groups; particularly preferably alkyl groups; and these groups may have substituents.

[0189] R Y2 The light-emitting element of this embodiment is preferably an alkyl group, cycloalkyl group, alkoxy group, cycloalkoxy group, aryl group, monovalent heterocyclic group, or substituted amino group, more preferably an alkyl group, cycloalkyl group, aryl group, or monovalent heterocyclic group, even more preferably an alkyl group, cycloalkyl group, or aryl group, and particularly preferably an alkyl group or aryl group, and these groups may have substituents.

[0190] X Y1 Because the light-emitting efficiency of the light-emitting element of this embodiment is superior, -C(R Y2 )2- or -C(R Y2 )2-C(R Y2 A group represented by )2-, more preferably -C(R Y2 It is a group represented by )2-.

[0191] Examples of constituent units represented by equation (Y) include the constituent units represented by the following equation. Note that in the equation, Z 1 and Z 2 This expresses the same meaning as above.

[0192] [ka]

[0193] [ka]

[0194] [ka]

[0195] [ka]

[0196] • Constituent units represented by formula (X) a X1 and a X2 This is usually an integer from 0 to 10, and is preferably an integer from 0 to 5, more preferably an integer from 0 to 3, even more preferably an integer from 0 to 2, and particularly preferably 0 or 1, as this provides better luminous efficiency for the light-emitting element of this embodiment.

[0197] R X1 , R X2 and R X3 The group is preferably an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, more preferably an aryl group or a monovalent heterocyclic group, and even more preferably an aryl group, and these groups may have substituents. R X1 , R X2 and R X3 Examples and preferred ranges of aryl groups and monovalent heterocyclic groups in are, respectively, Ar Y1 The examples and preferred ranges of aryl groups and monovalent heterocyclic groups in substituents that the group represented by may have are the same.

[0198] Ar X1 Ar X2 Ar X3 and Ar X4 Examples and preferred ranges of arylene groups and divalent heterocyclic groups in are, respectively, Ar Y1 The examples and preferred ranges of arylene groups and divalent heterocyclic groups are the same as those in the above. Ar X2 and Ar X4Examples and preferred ranges of the arylene group and the divalent heterocyclic group in a divalent group in which at least one arylene group and at least one divalent heterocyclic group are directly bonded are, respectively, Ar Y1 The examples and preferred ranges of arylene groups and divalent heterocyclic groups are the same as those in the above. Ar X2 and Ar X4 As a divalent group in which at least one arylene group and at least one divalent heterocyclic group are directly bonded, Ar Y1 Examples include divalent groups similar to those in which at least one arylene group and at least one divalent heterocyclic group are directly bonded. Ar X1 Ar X2 Ar X3 and Ar X4 This is preferably an arylene group which may have substituents.

[0199] Ar X1 ~Ar X4 and R X1 ~R X3 Examples and preferred ranges of substituents that the group represented by may have are Ar Y1 The examples and preferred ranges of substituents that the group represented by may have are the same.

[0200] The constituent units represented by equation (X) include the constituent units represented by the following equation. , where Z 2 This expresses the same meaning as above.

[0201] [ka]

[0202] [ka]

[0203] [ka]

[0204] [ka]

[0205] Examples of polymer compounds for the second layer include polymer compounds P-1 to P-12 shown in Table 1. Here, "others" refers to constituent units other than those represented by formula (Z), formula (Z'), formula (X), and formula (Y).

[0206] [Table 1]

[0207] The polymer compound having a crosslinking group may be a block copolymer, a random copolymer, an alternating copolymer, a graft copolymer, or any other form, but it is preferably a copolymer obtained by copolymerizing multiple types of raw material monomers. The number-average molecular weight of the polymer compound having a crosslinking group, in terms of polystyrene, is preferably 5 × 10⁻⁶. 3 ~1 × 10 6 Therefore, 1 × 10 4 ~5×10 5 And more preferably 2 × 10 4 ~1 × 10 5 The weight-average molecular weight of the polymer compound having a crosslinking group, in terms of polystyrene, is preferably 1 × 10⁻⁶. 4 ~2×10 6 Therefore, more preferably 2 × 10 4 ~1 × 10 6 And more preferably 5 × 10 4 ~5×10 5 And, particularly preferably, 1 × 10 5 ~3×10 5 That is the case.

[0208] • Method for producing polymer compounds having crosslinking groups Polymer compounds having crosslinking groups can be produced using known polymerization methods described in Chemical Review (Chem. Rev.), Vol. 109, pp. 897-1091 (2009), etc. Examples include polymerization by coupling reactions using transition metal catalysts such as the Suzuki reaction, Yamamoto reaction, Buchwald reaction, Stille reaction, Negishi reaction, and Kumada reaction. In the polymerization method described above, methods for introducing the monomer include introducing the entire amount of monomer into the reaction system at once, introducing a portion of the monomer and reacting it, then introducing the remaining monomer all at once, continuously, or in installments, and introducing the monomer continuously or in installments. Examples of transition metal catalysts include palladium catalysts and nickel catalysts. Post-treatment of the polymerization reaction is carried out by known methods, such as removing water-soluble impurities by liquid-liquid separation, or by adding the reaction solution after polymerization to a lower alcohol such as methanol, filtering the precipitate, and then drying it, either alone or in combination. If the purity of the polymer compound in the second layer is low, it can be purified by conventional methods such as recrystallization, reprecipitation, continuous extraction using a Soxhlet extractor, or column chromatography.

[0209] (Low molecular weight compounds containing crosslinking groups) The low molecular weight compound having a crosslinking group is preferably a compound represented by formula (Z'') because it provides better luminescence efficiency to the light-emitting element of this embodiment.

[0210] m B1 The examples and preferred ranges are the same as the examples and preferred ranges for mA. m B2 The example and preferred range for c are the same as the example and preferred range for c. m B3 The examples and preferred ranges for m are the same as the examples and preferred ranges for m. Ar 7 Examples and preferred ranges are, 5 This is the same as the example and preferred range. L B1 Examples and preferred ranges are K AThis is the same as the example and preferred range. The examples and preferred ranges for R''' are the same as the examples and preferred ranges for R''. The examples and preferred ranges of X'' are the same as the examples and preferred ranges of X'.

[0211] Examples of low molecular weight compounds having a crosslinking group include the compounds listed below, as well as the compound HTL-M2 described later.

[0212] [ka]

[0213] [ka]

[0214] [ka]

[0215] [ka]

[0216] [Second composition] The second layer may contain a composition (hereinafter also referred to as "the second composition") comprising a crosslinked compound having a crosslinking group and at least one material selected from the group consisting of a hole transport material, a hole injection material, an electron transport material, an electron injection material, a light-emitting material, and an antioxidant. In the second layer, the hole transport material, the hole injection material, the electron transport material, the electron injection material, and the light-emitting material are different from the crosslinked compound having a crosslinking group. The second composition may contain, individually or in combination of, a crosslinked compound having a crosslinking group, a hole transport material, a hole injection material, an electron transport material, an electron injection material, a light-emitting material, and an antioxidant. Examples and preferred ranges of hole transport materials, hole injection materials, electron transport materials, electron injection materials, light-emitting materials, and antioxidants contained in the second composition are the same as examples and preferred ranges of hole transport materials, hole injection materials, electron transport materials, electron injection materials, light-emitting materials, and antioxidants contained in the first composition.

[0217] In the second composition, the total content of the crosslinked compound having a crosslinking group, hole transport material, hole injection material, electron transport material, electron injection material, light-emitting material, and antioxidant may be within a range that allows the function of the second composition to be achieved. In the second composition, the total content of the crosslinked compound having a crosslinking group, hole transport material, hole injection material, electron transport material, electron injection material, light-emitting material, and antioxidant may be, for example, 1 to 100% by mass, 10 to 100% by mass, 30 to 100% by mass, 50 to 100% by mass, 70 to 100% by mass, or 90 to 100% by mass, based on the total amount of the second composition. In the second composition, the content of the hole transport material, hole injection material, electron transport material, electron injection material, and light-emitting material is typically 1 to 10,000 parts by mass, when the content of the crosslinked compound having a crosslinking group is 100 parts by mass. In the second composition, the content of the antioxidant is typically 0.00001 to 10 parts by mass, when the content of the crosslinked compound having a crosslinking group is 100 parts by mass.

[0218] (Second ink) The second layer can be formed using, for example, a composition containing a compound having a crosslinking group and a solvent (hereinafter also referred to as the "second ink"). The second ink may contain one or more compounds and solvents having crosslinking groups. The second ink can be suitably used in the wet process described in the section on the first ink. The preferred viscosity range for the second ink is the same as the preferred viscosity range for the first ink. Examples and preferred ranges of solvents contained in the second ink are the same as examples and preferred ranges of solvents contained in the first ink. In the second ink, the solvent content is such that the content of the compound having a crosslinking group is 100 by mass When expressed as parts, it is typically between 1,000 and 1,000,000 parts by mass.

[0219] The second ink may further contain at least one selected from the group consisting of hole transport materials, hole injection materials, electron transport materials, electron injection materials, light-emitting materials, and antioxidants. Examples and preferred ranges of hole transport materials, electron transport materials, hole injection materials, electron injection materials, light-emitting materials, and antioxidants that the second ink may further contain are the same as examples and preferred ranges of hole transport materials, electron transport materials, hole injection materials, electron injection materials, light-emitting materials, and antioxidants contained in the second composition. The second ink may further contain hole transport material, electron transport material, hole injection material, electron injection material, and light-emitting material, each typically in amounts of 1 to 10,000 parts by mass, based on 100 parts by mass of the crosslinking compound. The second ink may further contain antioxidant, typically in amounts of 0.00001 to 10 parts by mass, based on 100 parts by mass of the crosslinking compound.

[0220] <hibi> The light-emitting element of this embodiment is a light-emitting element having an anode, a cathode, and a first layer and a second layer provided between the anode and the cathode. The light-emitting element of this embodiment may further have layers other than the anode, cathode, first layer and second layer.

[0221] The first layer is typically a light-emitting layer (hereinafter referred to as the "first light-emitting layer"). The second layer is typically a hole injection layer, a hole transport layer, an emissive layer (i.e., an emissive layer separate from the first emissive layer, hereinafter referred to as the "second emissive layer"), or an electron transport layer, preferably a hole injection layer, a hole transport layer, or a second emissive layer, more preferably a hole injection layer or a hole transport layer, and even more preferably a hole transport layer.

[0222] The first layer and the second layer are preferably adjacent to each other, as this improves the luminous efficiency of the light-emitting element of this embodiment. The second layer is preferably a layer provided between the anode and the first layer, more preferably a hole injection layer, hole transport layer, or second light-emitting layer provided between the anode and the first layer, even more preferably a hole injection layer or hole transport layer provided between the anode and the first layer, and particularly preferably a hole transport layer provided between the anode and the first layer, since the light-emitting element of this embodiment has better luminous efficiency.

[0223] If the second layer is a second light-emitting layer provided between the anode and the first layer, the light-emitting element of this embodiment has better luminous efficiency, so it is preferable to further have at least one of a hole injection layer and a hole transport layer between the anode and the second layer. Also, if the second layer is a second light-emitting layer provided between the anode and the first layer, the light-emitting element of this embodiment has better luminous efficiency, so it is preferable to further have at least one of an electron injection layer and an electron transport layer between the cathode and the first layer.

[0224] If the second layer is a second light-emitting layer provided between the cathode and the first layer, the light-emitting element of this embodiment has better luminous efficiency, so it is preferable to further have at least one of a hole injection layer and a hole transport layer between the anode and the first layer. Also, if the second layer is a second light-emitting layer provided between the cathode and the first layer, the light-emitting element of this embodiment has better luminous efficiency, so it is preferable to further have at least one of an electron injection layer and an electron transport layer between the cathode and the second layer.

[0225] If the second layer is a hole transport layer provided between the anode and the first layer, the light-emitting element of this embodiment has better luminescence efficiency, so a hole injection layer is further provided between the anode and the second layer. This is preferable. Furthermore, if the second layer is a hole transport layer provided between the anode and the first layer, the luminescence efficiency of the light-emitting element of this embodiment is better, so it is preferable to further have at least one of the electron injection layer and the electron transport layer between the cathode and the first layer.

[0226] If the second layer is a hole injection layer provided between the anode and the first layer, the luminous efficiency of the light-emitting element of this embodiment is further improved, so it is preferable to further have a hole transport layer between the first layer and the second layer. Also, if the second layer is a hole injection layer provided between the anode and the first layer, the luminous efficiency of the light-emitting element of this embodiment is further improved, so it is preferable to further have at least one of the electron injection layer and the electron transport layer between the cathode and the first layer.

[0227] If the second layer is an electron transport layer provided between the cathode and the first layer, the luminous efficiency of the light-emitting element of this embodiment is further improved, so it is preferable to further have at least one of a hole injection layer and a hole transport layer between the anode and the first layer. Also, if the second layer is an electron transport layer provided between the cathode and the first layer, the luminous efficiency of the light-emitting element of this embodiment is further improved, so it is preferable to further have an electron injection layer between the cathode and the second layer.

[0228] A specific layer configuration of the light-emitting element of this embodiment is, for example, the layer configuration represented by (D1) to (D18). The light-emitting element of this embodiment usually has a substrate, but the layers may be stacked on the substrate starting from the anode, or stacked on the substrate starting from the cathode.

[0229] (D1) Anode / Second light-emitting layer (second layer) / First light-emitting layer (first layer) / Cathode (D2) Anode / Hole transport layer (second layer) / First light-emitting layer (first layer) / Cathode (D3) Anode / Hole injection layer / Second light-emitting layer (second layer) / First light-emitting layer (first layer) / Cathode (D4) Anode / Hole injection layer / Second light-emitting layer (second layer) / First light-emitting layer (first layer) / Electron transport layer / Cathode (D5) Anode / Hole injection layer / Second light-emitting layer (second layer) / First light-emitting layer (first layer) / Electron injection layer / Cathode (D6) Anode / Hole injection layer / Second light-emitting layer (second layer) / First light-emitting layer (first layer) / Electron transport layer / Electron injection layer / Cathode (D7) Anode / Hole injection layer / Hole transport layer (second layer) / First light-emitting layer (first layer) / Cathode (D8) Anode / Hole injection layer / Hole transport layer (second layer) / First light-emitting layer (first layer) / Electron transport layer / Cathode (D9) Anode / Hole injection layer / Hole transport layer (second layer) / First light-emitting layer (first layer) / Electron injection layer / Cathode (D10) Anode / Hole injection layer / Hole transport layer (second layer) / First light-emitting layer (first layer) / Electron transport layer / Electron injection layer / Cathode (D11) Anode / Hole injection layer / Hole transport layer / Second light-emitting layer (second layer) / First light-emitting layer (first layer) / Electron transport layer / Electron injection layer / Cathode (D12) Anode / Hole injection layer / Hole transport layer (second layer) / First light-emitting layer (first layer) / Second light-emitting layer / Electron transport layer / Electron injection layer / Cathode (D13) Anode / Hole injection layer / Hole transport layer / First light-emitting layer (first layer) / Second light-emitting layer (second layer) / Electron transport layer / Electron injection layer / Cathode (D14) Anode / Hole injection layer / Hole transport layer / First light-emitting layer (first layer) / Electron transport layer (second layer) / Electron injection layer / Cathode (D15) Anode / Hole injection layer / Hole transport layer (second layer) / Second light-emitting layer / First light-emitting layer (first layer) / Electron transport layer / Electron injection layer / Cathode (D16) Anode / Hole injection layer (second layer) / First light-emitting layer (first layer) / Cathode (D17) Anode / Hole injection layer (second layer) / First light-emitting layer (first layer) / Electron transport layer / Electron injection layer / Cathode (D18) Anode / Hole injection layer (second layer) / Hole transport layer / First light-emitting layer (first layer) / Electron transport layer / Electron injection layer / Cathode

[0230] In (D1) to (D18) above, " / " means that the preceding and succeeding layers are stacked adjacent to each other. For example, "Hole transport layer (second layer) / first light-emitting layer (first layer)" means that the hole transport layer (second layer) and the first light-emitting layer (first layer) are stacked adjacent to each other.

[0231] In the light-emitting element of this embodiment, the anode, hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer, and cathode may each be provided in two or more layers as needed. When there are multiple anodes, hole injection layers, hole transport layers, light-emitting layers, electron transport layers, electron injection layers, and cathodes, the materials constituting them may be the same or different. The thicknesses of the anode, hole injection layer, hole transport layer, first layer, second layer, light-emitting layer, electron transport layer, electron injection layer, and cathode are typically 1 nm to 1 μm, preferably 2 nm to 500 nm, and more preferably 5 nm to 150 nm. In the light-emitting element of this embodiment, the order, number, and thickness of the stacked layers can be adjusted taking into consideration the driving voltage and brightness lifespan of the light-emitting element.

[0232] [First light-emitting layer] The first light-emitting layer is typically the first layer.

[0233] [Second light-emitting layer] The second light-emitting layer is usually the second layer or a layer containing a light-emitting material, preferably a layer containing a light-emitting material. When the second light-emitting layer is a layer containing a light-emitting material, examples of the light-emitting material contained in the second light-emitting layer include the light-emitting material that may be contained in the second composition described above. The light-emitting material contained in the second light-emitting layer may be contained alone or in the form of two or more types. In this embodiment, if the light-emitting element has a second light-emitting layer, and the hole injection layer, hole transport layer, and electron transport layer described later are not the second layer, it is preferable that the second light-emitting layer is the second layer.

[0234] [Hole transport layer] The hole transport layer is a second layer or a layer containing a hole transport material, preferably a second layer. When the hole transport layer is a layer containing a hole transport material, the hole transport material may be, for example, the second composition described above. The hole transport material contained in the hole transport layer may be a single type or two or more types. If the light-emitting element of this embodiment has a hole transport layer, and the hole injection layer described later, the second light-emitting layer described above, and the electron transport layer described later are not the second layer, then it is preferable that the hole transport layer is the second layer.

[0235] [Electron transport layer] The electron transport layer is a second layer or a layer containing an electron transport material, preferably a layer containing an electron transport material. When the electron transport layer is a layer containing an electron transport material, examples of the electron transport material contained in the electron transport layer include the electron transport material that may also be contained in the second composition described above. The electron transport material contained in the electron transport layer may be contained alone or in the form of two or more types. If the light-emitting element of this embodiment has an electron transport layer, and the hole injection layer described later, the second light-emitting layer described above, and the hole transport layer described above are not the second layer, then it is preferable that the electron transport layer is the second layer.

[0236] [Hole injection layer] The hole injection layer is a second layer or a layer containing a hole injection material, preferably a layer containing a hole injection material. When the hole injection layer is a layer containing a hole injection material, the hole injection material contained in the hole injection layer may include, for example, the hole injection material which may also be contained in the second composition described above. The hole injection material contained in the hole injection layer may be contained alone or in the form of two or more types. If the light-emitting element of this embodiment has a hole injection layer, and the aforementioned second light-emitting layer, hole transport layer, and electron transport layer are not the second layer, then it is preferable that the hole injection layer is the second layer.

[0237] [Electron injection layer] The electron injection layer is a layer containing an electron injection material. Examples of electron injection materials contained in the electron injection layer include the electron injection material which may also be contained in the second composition described above. The electron injection material contained in the electron injection layer may be a single type or two or more types.

[0238] [Substrate / Electrode] In a light-emitting element, the substrate is preferably one that does not undergo chemical changes during the formation of electrodes and organic layers. The substrate may be made of materials such as glass, plastic, or silicon. If an opaque substrate is used, it is preferable that the electrode furthest from the substrate is transparent or semi-transparent.

[0239] Examples of anode materials include conductive metal oxides and translucent metals, preferably indium oxide, zinc oxide, tin oxide; conductive compounds such as indium tin oxide (ITO) and indium zinc oxide; silver-palladium-copper composites (APC); NESA, gold, platinum, silver, and copper.

[0240] Examples of cathode materials include metals such as lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, aluminum, zinc, and indium; alloys of two or more of these; alloys of one or more of these with one or more of silver, copper, manganese, titanium, cobalt, nickel, tungsten, and tin; and graphite and graphite intercalation compounds. Examples of alloys include magnesium-silver alloys, magnesium-indium alloys, magnesium-aluminum alloys, indium-silver alloys, lithium-aluminum alloys, lithium-magnesium alloys, lithium-indium alloys, and calcium-aluminum alloys.

[0241] In the light-emitting element of this embodiment, at least one of the anode and cathode is usually transparent or translucent, but it is preferable that the anode is transparent or translucent.

[0242] Methods for forming the anode and cathode include, for example, vacuum deposition, sputtering, ion plating, plating, and lamination.

[0243] [Manufacturing method for generating light-emitting elements] In the method for manufacturing a light-emitting element of this embodiment, when using a low molecular weight compound, examples of dry methods such as vacuum deposition and wet methods described in the section on the first ink can be used, and when using a polymer compound, examples of wet methods described in the section on the first ink can be used. In the method for manufacturing a light-emitting element of this embodiment, the first layer, the second layer, and layers other than the first and second layers can be formed using the various inks and inks containing the various materials described above, as described in the section on the first ink. It may be formed by a wet method, or by a dry method such as vacuum deposition.

[0244] Examples of methods for forming the first and second layers include a dry method and a wet method, and the wet method is preferred because it facilitates the manufacture of the light-emitting element of this embodiment. In the method for forming the first and second layers, an example of a dry method is vacuum deposition. In the method for forming the first and second layers, an example of a wet method is the wet method described in the section on the first ink.

[0245] When the first layer is formed by a wet process, it is preferable to use the first ink, as this facilitates the manufacture of the light-emitting element of the embodiment. That is, it is preferable to form the first layer by a wet process using the first ink. When the second layer is formed by a wet process, it is preferable to use a second ink, as this facilitates the manufacture of the light-emitting element of the embodiment. That is, it is preferable to form the second layer by a wet process using the second ink.

[0246] In the method for manufacturing a light-emitting element of this embodiment, a layer containing a crosslinked compound having a crosslinking group (for example, a second layer) can be formed, for example, by forming a layer containing a compound having a crosslinking group and then heating or irradiating it with light (preferably heating) to crosslink the compound having a crosslinking group contained in the layer. When the compound having a crosslinking group is contained in the second layer in a crosslinked state (a crosslinked compound having a crosslinking group), the layer is substantially insoluble in the solvent. Therefore, a layer containing a crosslinked compound having a crosslinking group can be suitably used for lamination in the manufacturing of a light-emitting element of this embodiment.

[0247] From the above viewpoint, in the method for manufacturing a light-emitting element of this embodiment, the step of forming a second layer preferably includes the step of forming a layer containing a compound having a crosslinking group, and then crosslinking the compound having a crosslinking group contained in the layer to form a second layer containing a crosslinked body of the compound having a crosslinking group. In the step of forming the second layer, as a method for crosslinking the compound having a crosslinking group, a method of crosslinking by heating or light irradiation is preferred, and a method of crosslinking by heating is more preferred, as it facilitates the manufacture of the light-emitting element of this embodiment.

[0248] The heating temperature for crosslinking is typically 25°C to 300°C, preferably 50°C to 260°C, more preferably 130°C to 230°C, and even more preferably 180°C to 210°C. The heating time is usually 0.1 to 1000 minutes, preferably 0.5 to 500 minutes, more preferably 1 to 120 minutes, and even more preferably 10 to 60 minutes. The types of light used for crosslinking include, for example, ultraviolet light, near-ultraviolet light, and visible light.

[0249] One step in forming the second layer is, for example, to form a layer by a wet process using a second ink, and then to crosslink the crosslinking group compound contained in the layer to form the second layer.

[0250] Examples of analytical methods for components contained in the first layer, the second layer, or layers other than the first and second layers include chemical separation analysis methods such as extraction, instrumental analysis methods such as infrared spectroscopy (IR), nuclear magnetic resonance spectroscopy (NMR), and mass spectrometry (MS), and analytical methods that combine chemical separation analysis methods and instrumental analysis methods. By performing solid-liquid extraction using organic solvents such as toluene, xylene, chloroform, and tetrahydrofuran on the first layer, the second layer, or layers other than the first and second layers, it is possible to separate components that are substantially insoluble in the organic solvent (insoluble components) from components that are soluble in the organic solvent (soluble components). The insoluble components can be analyzed by infrared spectroscopy or nuclear magnetic resonance spectroscopy, and the soluble components can be analyzed by nuclear magnetic resonance spectroscopy or mass spectrometry.

[0251] The light-emitting element of this embodiment can be manufactured, for example, by sequentially laminating each layer on a substrate. Specifically, a light-emitting element can be manufactured by providing an anode on a substrate, providing layers such as a hole injection layer and a hole transport layer on top of it, providing a light-emitting layer on top of that, providing layers such as an electron transport layer and an electron injection layer on top of that, and then laminating a cathode on top of that. Another manufacturing method involves providing a cathode on a substrate, providing layers such as an electron injection layer, an electron transport layer, a light-emitting layer, a hole transport layer, and a hole injection layer on top of it, and then laminating an anode on top of that. Yet another manufacturing method involves joining an anode or an anode-side substrate with each layer laminated on the anode to a cathode or a cathode-side substrate with each layer laminated on the cathode, facing each other.

[0252] In the manufacturing of the light-emitting element of this embodiment, when the material used to form the hole injection layer, the material used to form the light-emitting layer, the material used to form the hole transport layer, the material used to form the electron transport layer, and the material used to form the electron injection layer dissolves in the solvent used when forming the layer adjacent to the hole injection layer, light-emitting layer, hole transport layer, electron transport layer, and electron injection layer, it is preferable to avoid dissolving the material in the solvent. Preferred methods for avoiding material dissolution include i) using a material having crosslinking groups, or ii) creating a difference in the solubility of adjacent layers in the solvent. In method i), after forming a layer using a material having crosslinking groups, the layer can be made insoluble by crosslinking the crosslinking groups. In method ii), for example, when laminating an electron transport layer on top of a light-emitting layer by utilizing a difference in solubility, the electron transport layer can be laminated on top of the light-emitting layer by using an ink with low solubility relative to the light-emitting layer.

[0253] [Application] The light-emitting element of this embodiment can be suitably used as a light source for the backlight of a liquid crystal display device, a light source for illumination, organic EL lighting, and display devices such as computers, televisions, and mobile terminals (for example, organic EL displays and organic EL televisions).

[0254] Although preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. [Examples]

[0255] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0256] In the examples, the molecular weight of the compounds was calculated using the Molecular Weight value from ChemDraw Professional 22.2 (Revvity Signals Software).

[0257] In the examples, the number-average molecular weight (Mn) and weight-average molecular weight (Mw) of the polymer compounds, calculated in terms of polystyrene, were determined by size exclusion chromatography (SEC) using tetrahydrofuran as the mobile phase. The measurement conditions for each SEC were as follows: The polymer compound to be measured was dissolved in tetrahydrofuran at a concentration of approximately 0.05% by mass, and 10 μL was injected into the SEC. The mobile phase was flowed at a flow rate of 2.0 mL / min. A PLgel MIXED-B column (Polymer Laboratories) was used. A UV-VIS detector (Shimadzu Corporation, product name: SPD-10Avp) was used as the detector.

[0258] <Synthesis Example 1> Synthesis of Compounds M1-M8 Compound M1 was synthesized according to the method described in Japanese Patent Publication No. 2011-174062. Compound M2 was synthesized according to the method described in International Publication No. 2005 / 049546. Compound M3 was synthesized according to the method described in International Publication No. 02 / 045184. Compound M4 was synthesized according to the method described in Japanese Patent Publication No. 2008-106241. Compound M5 was synthesized according to the method described in International Publication No. 2015 / 145871. Compound M6 was synthesized according to the method described in International Publication No. 2013 / 146806. Compound M7 was synthesized according to the method described in Japanese Patent Publication No. 2010-215886. Compound M8 was synthesized according to the method described in Japanese Patent Publication No. 2010-189630.

[0259] [ka]

[0260] <Synthesis Example 2> Synthesis of polymer compounds HTL-P1~HTL-P3 and HTL-PC1 The polymer compounds (copolymers) HTL-P1 to HTL-P3 and HTL-PC1 were synthesized using the types and molar ratios of compounds listed in Table 2, and the synthesis method described in the same table. The Mn and Mw of the obtained polymer compounds are as shown in Table 2.

[0261] [Table 2]

[0262] <Compounds HTL-M1 and HTL-M2> Compounds HTL-M1 and HTL-M2 were manufactured by Luminescence Technology.

[0263] [ka]

[0264] <Synthesis Example 3> Synthesis of Fluorescent Compound E1 The fluorescent compound E1 was synthesized according to the method described in International Publication No. 2007 / 058368.

[0265] [ka]

[0266] S1 level value, T1 level value and ΔE of fluorescent compound E1 ST The values ​​were 2.3836 eV, 1.5955 eV, and 0.788 eV, respectively.

[0267] <Synthesis Example 4> Synthesis and acquisition of compounds T1-T10 Compounds T1-T5 and T8-T10 were sourced from Luminescence Technology. Compound T6 was synthesized according to the method described in Adv. Mater. 2013, 25, 2205-2211. Compound T7 was synthesized according to the method described in J.Mater.C.C.2014,2,421-424.

[0268] [ka]

[0269] ΔE of compounds T1-T10 ST The values ​​were as shown in Table 3. [Table 3]

[0270] <Example D1> Fabrication and evaluation of light-emitting element D1 (Formation of anode and hole injection layer) An anode was formed by depositing an ITO film to a thickness of 45 nm onto a glass substrate using the sputtering method. On this anode, ND-3202 (manufactured by Nissan Chemical Corporation), a hole injection material, was deposited to a thickness of 65 nm using the spin coating method, and a hole injection layer was formed by heating it on a hot plate at 240°C for 10 minutes in an atmospheric environment.

[0271] (Formation of the second layer) The polymer compound HTL-P1 was dissolved in xylene at a concentration of 0.6% by mass. Using the resulting xylene solution, a 20 nm thick film was deposited on the hole-injection layer by spin coating. A second layer was formed by heating the film on a hot plate at 200°C for 30 minutes under a nitrogen gas atmosphere. This heating caused the polymer compound HTL-P1 to become a crosslinked material.

[0272] (Formation of the first layer) Compound T1, compound T2, and fluorescent compound E1 (compound T1 / compound T2 / fluorescent compound E1 = 49% by mass / 48% by mass / 3% by mass) were dissolved in chlorobenzene so that their total concentration was 2% by mass. Using the obtained chlorobenzene solution, a film with a thickness of 80 nm was deposited on the second layer by spin coating, and the first layer was formed by heating at 150°C for 10 minutes under a nitrogen gas atmosphere.

[0273] (Formation of cathode) The substrate on which the first layer has been formed is deposited in the vapor deposition machine, 1.0 × 10 -4 After reducing the pressure to below Pa, a cathode was formed by depositing approximately 4 nm of sodium fluoride onto the first layer, followed by approximately 80 nm of aluminum onto the sodium fluoride layer. Subsequently, the substrate with the cathode formed was sealed with a glass substrate to fabricate the light-emitting element D1.

[0274] (Evaluation of light-emitting elements) EL emission was observed when a voltage was applied to the light-emitting element D1. The current density of the light-emitting element D1 was 50 mA / cm². 2 The luminous efficiency [cd / A] and CIE chromaticity coordinates were measured.

[0275] <Example D2 and Comparative Example CD1> Fabrication and evaluation of light-emitting elements D2 and CD1 Except for using the materials and material ratios listed in Table 4 in Example D1 (formation of the first layer), light-emitting elements D2 and CD1 were fabricated in the same manner as in Example D1. EL emission was observed when a voltage was applied to light-emitting elements D2 and CD1. Current of light-emitting elements D2 and CD1 Density is 50 mA / cm³ 2 The luminous efficiency [cd / A] and CIE chromaticity coordinates were measured.

[0276] The results for Examples D1, D2 and Comparative Example CD1 are shown in Table 4. In Table 4, luminous efficiency (relative value) refers to the ratio of the luminous efficiency [cd / A] of light-emitting elements D1 and D2 when the luminous efficiency [cd / A] of light-emitting element CD1 is set to 1.0.

[0277] [Table 4]

[0278] <Examples D3, D4 and Comparative Example CD2> Fabrication and Evaluation of Light-Emitting Devices D3, D4 and CD2 Except for using the materials and material ratios listed in Table 5 in Example D1 (formation of the first layer), light-emitting elements D3, D4, and CD2 were fabricated in the same manner as in Example D1. EL emission was observed when a voltage was applied to light-emitting elements D3, D4, and CD2. The current density of light-emitting elements D3, D4, and CD2 was 10 mA / cm². 2 The luminous efficiency [cd / A] and CIE chromaticity coordinates were measured.

[0279] The results for Examples D3, D4 and Comparative Example CD2 are shown in Table 5. In Table 5, luminous efficiency (relative value) refers to the ratio of the luminous efficiency [cd / A] of light-emitting elements D3 and D4 when the luminous efficiency [cd / A] of light-emitting element CD2 is set to 1.0.

[0280] [Table 5]

[0281] <Examples D5, D6 and Comparative Example CD3> Fabrication and Evaluation of Light-Emitting Devices D5, D6 and CD3 Except for using the materials and material ratios listed in Table 6 in Example D1 (formation of the first layer), light-emitting elements D5, D6, and CD3 were fabricated in the same manner as in Example D1. EL emission was observed when a voltage was applied to light-emitting elements D5, D6, and CD3. The current density of light-emitting elements D5, D6, and CD3 was 100 mA / cm². 2 The luminous efficiency [cd / A] and CIE chromaticity coordinates were measured.

[0282] The results for Examples D5, D6 and Comparative Example CD3 are shown in Table 6. In Table 6, luminous efficiency (relative value) refers to the ratio of the luminous efficiency [cd / A] of light-emitting elements D5 and D6 when the luminous efficiency [cd / A] of light-emitting element CD3 is set to 1.0.

[0283] [Table 6]

[0284] <Examples D7, D8 and Comparative Example CD4> Fabrication and Evaluation of Light-Emitting Devices D7, D8 and CD4 Except for using the materials and material ratios listed in Table 7 in Example D1 (formation of the second layer) and (formation of the first layer), light-emitting elements D7, D8, and CD4 were fabricated in the same manner as in Example D1. EL emission was observed when a voltage was applied to light-emitting elements D7, D8, and CD4. The current density of light-emitting elements D7, D8, and CD4 was 20 mA / cm². 2 The luminous efficiency [cd / A] and CIE chromaticity coordinates were measured.

[0285] The results for Examples D7, D8 and Comparative Example CD4 are shown in Table 7. In Table 7, luminous efficiency (relative value) refers to the ratio of the luminous efficiency [cd / A] of light-emitting elements D7 and D8 when the luminous efficiency [cd / A] of light-emitting element CD4 is set to 1.0.

[0286] [Table 7]

[0287] <Examples D9-D11> Fabrication and evaluation of light-emitting elements D9-D11 Except for using the materials and material ratios listed in Table 8 in the (formation of the second layer) and (formation of the first layer) of Example D1, light-emitting elements D9 to D11 were fabricated in the same manner as in Example D1. EL emission was observed when a voltage was applied to light-emitting elements D9 to D11. The current density of light-emitting elements D9 to D11 was 15 mA / cm². 2 The luminous efficiency [cd / A] and CIE chromaticity coordinates were measured.

[0288] The results for Examples D9 to D11 are shown in Table 8. In Table 8, luminous efficiency (relative value) refers to the ratio of the luminous efficiency [cd / A] of light-emitting elements D9 and D10 when the luminous efficiency [cd / A] of light-emitting element D11 is set to 1.0.

[0289] [Table 8]

[0290] <Examples D12, D13 and Comparative Example CD5> Fabrication and Evaluation of Light-Emitting Devices D12, D13 and CD5 Except for using the materials and material ratios listed in Table 9 in the (formation of the second layer) and (formation of the first layer) of Example D1, light-emitting elements D12, D13, and CD5 were fabricated in the same manner as in Example D1. EL emission was observed when a voltage was applied to the light-emitting elements D12, D13, and CD5. The current density of the light-emitting elements D12, D13, and CD5 was 10 mA / cm². 2 The luminous efficiency [cd / A] and CIE chromaticity coordinates were measured.

[0291] The results for Examples D12, D13, and CD5 are shown in Table 9. In Table 9, luminous efficiency (relative value) refers to the ratio of the luminous efficiency [cd / A] of light-emitting elements D12 and D13 when the luminous efficiency [cd / A] of light-emitting element CD5 is set to 1.0.

[0292] [Table 9]

[0293] <Examples D14-D16> Fabrication and evaluation of light-emitting elements D14-D16 Except for using the materials and material ratios listed in Table 10 in Example D1 (formation of the second layer) and (formation of the first layer), light-emitting elements D14 to D16 were fabricated in the same manner as in Example D1. EL emission was observed when a voltage was applied to light-emitting elements D14 to D16. The current density of light-emitting elements D14 to D16 was 20 mA / cm². 2 The luminous efficiency [cd / A] and CIE chromaticity coordinates were measured.

[0294] The results for Examples D14 to D16 are shown in Table 10. In Table 10, luminous efficiency (relative value) refers to the ratio of the luminous efficiency [cd / A] of light-emitting elements D14 and D15 when the luminous efficiency [cd / A] of light-emitting element D16 is set to 1.0.

[0295] [Table 10]

[0296] <Examples D17, D18 and Comparative Example CD6> Fabrication and Evaluation of Light-Emitting Devices D17, D18 and CD6 In Example D1, except that in the (formation of the second layer) "mixture of polymer compound HTL-P1 dissolved in xylene at a concentration of 0.6 mass%" was replaced with "mixture of compound HTL-M1 dissolved in xylene at a concentration of 0.8 mass%", and in the (formation of the first layer) the materials and material ratios listed in Table 11 were used, light-emitting elements D17, D18, and CD6 were fabricated in the same manner as in Example D1. EL emission was observed when a voltage was applied to light-emitting elements D17, D18, and CD6. The current density of light-emitting elements D17, D18, and CD6 was 30 mA / cm². 2 The luminous efficiency [cd / A] and CIE chromaticity coordinates were measured.

[0297] The results for Examples D17, D18 and Comparative Example CD6 are shown in Table 11. In Table 11, luminous efficiency (relative value) refers to the ratio of the luminous efficiency [cd / A] of light-emitting elements D17 and D18 when the luminous efficiency [cd / A] of light-emitting element CD6 is set to 1.0.

[0298] [Table 11]

[0299] <Example D19 and Comparative Example CD7> Fabrication and Evaluation of Light-Emitting Devices D19 and CD7 Except for using the materials and material ratios listed in Table 12 in Example D17 (formation of the first layer), the light-emitting elements D19 and CD7 were fabricated in the same manner as in Example D17. EL emission was observed when a voltage was applied to the light-emitting elements D19 and CD7. The current density of the light-emitting elements D19 and CD7 was 20 mA / cm². 2 The luminous efficiency [cd / A] and CIE chromaticity coordinates were measured.

[0300] The results for Example D19 and Comparative Example CD7 are shown in Table 12. In Table 12, luminous efficiency (relative value) refers to the ratio of the luminous efficiency [cd / A] of light-emitting element D19 to the luminous efficiency [cd / A] of light-emitting element CD7, which is set to 1.0.

[0301] [Table 12]

[0302] <Examples D20, D21 and Comparative Example CD8> Fabrication and Evaluation of Light-Emitting Devices D20, D21 and CD8 Except for using the materials and material ratios listed in Table 13 in Example D17 (formation of the second layer) and (formation of the first layer), light-emitting elements D20, D21, and CD8 were fabricated in the same manner as in Example D17. EL emission was observed when a voltage was applied to the light-emitting elements D20, D21, and CD8. The current density of the light-emitting elements D20, D21, and CD8 was 10 mA / cm². 2 The luminous efficiency [cd / A] and CIE chromaticity coordinates were measured.

[0303] The results for Examples D20, D21 and Comparative Example CD8 are shown in Table 13. In Table 13, luminous efficiency (relative value) refers to the ratio of the luminous efficiency [cd / A] of light-emitting elements D20 and D21 when the luminous efficiency [cd / A] of light-emitting element CD8 is set to 1.0.

[0304] [Table 13]

[0305] <Example D22 and Comparative Example CD9> Fabrication and evaluation of light-emitting elements D22 and CD9 Except for using the materials and material ratios listed in Table 14 in Example D17 (formation of the second layer) and (formation of the first layer), the light-emitting elements D22 and CD9 were fabricated in the same manner as in Example D17. EL emission was observed when a voltage was applied to the light-emitting elements D22 and CD9. The current density of the light-emitting elements D22 and CD9 was 5 mA / cm². 2The luminous efficiency [cd / A] and CIE chromaticity coordinates were measured.

[0306] The results for Example D22 and Comparative Example CD9 are shown in Table 14. In Table 14, luminous efficiency (relative value) refers to the ratio of the luminous efficiency [cd / A] of light-emitting element D22 to the luminous efficiency [cd / A] of light-emitting element CD9, which is set to 1.0.

[0307] [Table 14]

[0308] <Example D23 and Comparative Example CD10> Fabrication and evaluation of light-emitting elements D23 and CD10 Except for using the materials and material ratios listed in Table 15 in Example D17 (formation of the second layer) and (formation of the first layer), the light-emitting elements D23 and CD10 were fabricated in the same manner as in Example D17. EL emission was observed when a voltage was applied to the light-emitting elements D23 and CD10. The current density of the light-emitting elements D23 and CD10 was 20 mA / cm². 2 The luminous efficiency [cd / A] and CIE chromaticity coordinates were measured.

[0309] The results for Example D23 and Comparative Example CD10 are shown in Table 15. In Table 15, luminous efficiency (relative value) refers to the ratio of the luminous efficiency [cd / A] of light-emitting element D23 to the luminous efficiency [cd / A] of light-emitting element CD10, which is set to 1.0.

[0310] [Table 15]

[0311] <Examples D24-D26 and Comparative Example CD11> Fabrication and Evaluation of Light-Emitting Devices D24-D26 and CD11 Except for using the materials and material ratios listed in Table 16 in the (formation of the second layer) and (formation of the first layer) of Example D1, light-emitting elements D24-D26 and CD11 were fabricated in the same manner as in Example D1. EL emission was observed when a voltage was applied to light-emitting elements D24-D26 and CD11. The current density of light-emitting elements D24-D26 and CD11 was 75 mA / cm². 2 The luminous efficiency [cd / A] and CIE chromaticity coordinates were measured.

[0312] The results for Examples D24-D26 and Comparative Example CD11 are shown in Table 16. In Table 16, luminous efficiency (relative value) refers to the ratio of the luminous efficiency [cd / A] of light-emitting elements D24-D26 when the luminous efficiency [cd / A] of light-emitting element CD11 is set to 1.0.

[0313] [Table 16]

[0314] <Example D27 and Comparative Example CD12> Fabrication and evaluation of light-emitting elements D27 and CD12 Except for using the materials and material ratios listed in Table 17 in Example D1 (formation of the second layer) and (formation of the first layer), the light-emitting elements D27 and CD12 were fabricated in the same manner as in Example D1. EL emission was observed when a voltage was applied to the light-emitting elements D27 and CD12. The current density of the light-emitting elements D27 and CD12 was 5 mA / cm². 2 The luminous efficiency [cd / A] and CIE chromaticity coordinates were measured.

[0315] The results for Example D27 and Comparative Example CD12 are shown in Table 17. In Table 17, luminous efficiency (relative value) refers to the ratio of the luminous efficiency [cd / A] of light-emitting element D27 to the luminous efficiency [cd / A] of light-emitting element CD12, which is set to 1.0.

[0316] [Table 17]

[0317] In each of the above examples and comparative examples, compounds T1 to T10 were used as host materials. Furthermore, in each of the above examples and comparative examples, the fluorescent compound E1 was used as a guest material.

Claims

1. A light-emitting element having an anode, a cathode, and a first layer and a second layer provided between the anode and the cathode, The first layer is a layer containing a fluorescent compound in which the absolute value of the difference between the energy level of the lowest triplet excited state and the energy level of the lowest singlet excited state is greater than 0.50 eV, and two or more compounds T that satisfy at least one of requirements (i) and (ii). A light-emitting element, wherein the second layer is a layer containing a crosslinked compound having a crosslinking group. (i) The absolute value of the difference between the energy level of the lowest triplet excited state and the energy level of the lowest singlet excited state is 0.25 eV or less. (ii) This is a compound represented by formula (T-1). 【Chemistry 1】 [In the formula, n Ｔ１ n represents a non-negative integer. Ｔ１ If multiple instances exist, they may be identical or different. Ar Ｔ１ Ar represents a substituted amino group or a monovalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which each substituent is bonded. Ｔ１ If multiple such groups exist, they may be identical or different, and they may be directly bonded to each other or bonded via divalent groups to form a ring. However, Ar Ｔ１ In this, the monovalent heterocyclic group contains a nitrogen atom that does not form a double bond within the ring, and within the ring are a group represented by -N-, a group represented by -C(=O)-, a group represented by -S(=O)-, and -S(=O) ２ It is a monovalent heterocyclic group that does not contain the group represented by -. L Ｔ１ L represents a divalent group, which may have substituents. If there are multiple substituents, they may be the same or different, and they may bond to each other to form a ring with the atom to which each substituent is bonded. Ｔ１ If multiple such groups exist, they may be identical or different, and they may be directly bonded to each other or bonded via divalent groups to form a ring. Ar Ｔ２ is a group represented by -C(=O)-, a group represented by -S(=O)-, a group represented by -S(=O) ２ -, an aromatic hydrocarbon group having an electron-withdrawing group, an aromatic hydrocarbon group containing a group represented by -C(=O)- in the ring, or a group represented by =N-, a group represented by -C(=O)-, a group represented by -S(=O)- and -S(=O) ２ - is a heterocyclic group containing at least one group selected from the group consisting of groups represented by -, and these groups may have substituents. When there are a plurality of these substituents, they may be the same or different, and may be bonded to each other to form a ring together with the atoms to which they are each bonded. n Ｔ２ represents an integer greater than or equal to 1. However, Ar Ｔ２ is a group represented by -C(=O)-, a group represented by -S(=O)-, or -S(=O) ２ If the group is represented by -, then n Ｔ２ The answer is 2. Ar Ｔ１ and L Ｔ１ Ar may form a ring by directly bonding with or via a divalent group. Ｔ２ and L Ｔ１ Ar may form a ring by directly bonding with or via a divalent group. Ｔ１ and Ar Ｔ２ It may form a ring by directly bonding with or via a divalent group.

2. The Ar Ｔ１ At least one of them contains a nitrogen atom that does not form a double bond within the ring, Furthermore, within the ring, there is a group represented by =N-, a group represented by -C(=O)-, a group represented by -S(=O)-, and -S(=O) ２ The light-emitting element according to claim 1, wherein the group is obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from a polycyclic heterocyclic compound that does not contain the group represented by -, and the group may have substituents.

3. The light-emitting element according to claim 2, wherein the polycyclic heterocyclic compound is a tricyclic, tetracyclic, pentacyclic, or hexacyclic heterocyclic compound.

4. The Ar Ｔ２ However, the group represented by -C (=O)-, -S (=O) ２ A group represented by -, an aromatic hydrocarbon group having an electron-withdrawing group, or a group represented by =N-, a group represented by -C(=O)-, and -S(=O) within the ring. ２ The light-emitting element according to claim 3, comprising a heterocyclic group containing at least one group selected from the group consisting of groups represented by -, and these groups may have substituents.

5. The light-emitting element according to any one of claims 1 to 4, wherein at least one of the compound T satisfies requirement (ii).

6. The light-emitting element according to claim 5, wherein the first layer contains two or more compounds T that satisfy requirement (ii).

7. The light-emitting element according to any one of claims 1 to 4, wherein the fluorescent compound is a fluorescent compound represented by formula (B). 【Chemistry 2】 [In the formula, n 1B This represents an integer between 0 and 15, inclusive. Ar 1B represents an aromatic hydrocarbon group of a fused ring, and these groups may have substituents. If there are multiple substituents, they may be bonded to each other, forming a ring with the atom to which each substituent is bonded. R 1B R represents an alkyl group, cycloalkyl group, alkoxy group, cycloalkoxy group, aryl group, monovalent heterocyclic group, substituted amino group, alkenyl group, cycloalkenyl group, alkynyl group, or cycloalkynyl group, and these groups may have substituents. 1B If multiple atoms exist, they may be identical or different, and they may bond to each other, forming a ring with the carbon atoms to which they are bonded.

8. The Ar 1B The light-emitting element according to claim 7, wherein the group is obtained by removing one or more hydrogen atoms directly bonded to carbon atoms constituting the ring from a naphthalene ring, anthracene ring, phenanthrene ring, dihydrophenanthrene ring, triphenylene ring, naphthalene ring, fluorene ring, spirobifluorene ring, pyrene ring, perylene ring, chrysene ring, indene ring, fluorantene ring, benzofluorantene ring, or acenaphthofluorantene ring, and these groups may have substituents.

9. The aforementioned R 1B The light-emitting element according to claim 8, wherein the group is an alkyl group, an aryl group, or a substituted amino group, and these groups may have substituents.

10. The compound having the crosslinking group is a constituent unit represented by formula (Z) and / or formula (Z') A light-emitting element according to any one of claims 1 to 4, which is a polymer compound containing a constituent unit represented by or a compound represented by formula (Z''). 【Transformation 3】 [In the formula, n represents an integer greater than or equal to 1. nA represents a non-negative integer. If there are multiple nA values, they may be the same or different. Ar ３ represents a hydrocarbon group, a heterocyclic group, or a group in which at least one hydrocarbon group and at least one heterocyclic group are directly bonded, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which each substituent is bonded. L Ａ R' represents an alkylene group, a cycloalkylene group, an arylene group, a divalent heterocyclic group, a group represented by -N(R')-, an oxygen atom, or a sulfur atom, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which they are bonded. R' represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which they are bonded. Ａ If multiple instances exist, they may be identical or different. X represents a bridging group. If there are multiple X's, they may be the same or different. 【Chemistry 4】 [In the formula, mA, m, and c each independently represent a non-negative integer. If there are multiple values ​​of mA, they may be the same or different. If there are multiple instances of 'm', they may be the same or different. Ar ５ Ar represents a hydrocarbon group, a heterocyclic group, or a group in which at least one hydrocarbon group and at least one heterocyclic group are directly bonded, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which each substituent is bonded. ５ If multiple instances exist, they may be identical or different. Ar ４ and Ar ６ Each of these independently represents an arylene group or a divalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may bond to each other to form a ring with the atom to which they are bonded. K Ａ represents an alkylene group, a cycloalkylene group, an arylene group, a divalent heterocyclic group, a group represented by -N(R'')-, an oxygen atom, or a sulfur atom, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which each substituent is bonded. R'' represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which each substituent is bonded. K Ａ If multiple instances exist, they may be identical or different. X' represents a hydrogen atom, a bridging group, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which each substituent is bonded. If there are multiple X' groups, they may be the same or different, provided that at least one X' is a bridging group. 【Transformation 5】 [In the formula, I understand Ｂ１ , m Ｂ２ and m Ｂ３ Each of these independently represents a non-negative integer. There are multiple m Ｂ１ They may be the same or different. Ｂ３ If multiple instances exist, they may be identical or different. Ar ７ Ar represents a hydrocarbon group, a heterocyclic group, or a group in which at least one hydrocarbon group and at least one heterocyclic group are directly bonded, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which each substituent is bonded. ７ If multiple instances exist, they may be identical or different. L Ｂ１ R''' represents an alkylene group, a cycloalkylene group, an arylene group, a divalent heterocyclic group, a group represented by -N(R''')-, an oxygen atom, or a sulfur atom, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which they are bonded. R''' represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which they are bonded. Ｂ１ If there are multiple X''s, they may be the same or different. X'' represents a bridging group, a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other, forming a ring with the atom to which each substituent is bonded. Multiple X''s may be the same or different. However, if there are multiple X''s Of the X'', at least one is a crosslinking group.

11. The light-emitting element according to any one of claims 1 to 4, wherein the first layer further contains at least one selected from the group consisting of hole transport material, hole injection material, electron transport material, electron injection material, light-emitting material, and antioxidant.

12. The light-emitting element according to any one of claims 1 to 4, wherein the first layer and the second layer are adjacent to each other.

13. The light-emitting element according to any one of claims 1 to 4, wherein the second layer is a layer provided between the anode and the first layer.

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