Light-emitting element

Abstract

To provide a light-emitting element with a low driving voltage. [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 contains a phosphorescent compound and two or more compounds represented by formula (T-1), and the second layer contains a crosslinked polymer compound containing a structural unit having a crosslinking group, and at least two of the compounds represented by formula (T-1) contain Ar T2 However, if the group is a monocyclic and six-membered heterocyclic ring containing a group represented by =N- within the ring, then the at least two compounds are light-emitting elements such that (i) the difference in the number of nitrogen atoms constituting the monocyclic and six-membered heterocyclic ring containing the group represented by =N- within the ring is 2 or more, and / or (ii) the difference in molecular weight is 80 or more. TIFF2026053953000068.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 proposes an organic electroluminescent device having a light-emitting layer formed by wet deposition of a composition containing a phosphorescent material, a charge-transporting compound, and a phenolic compound having substituents on only two of the 2, 4, and 6 positions of a phenolic hydroxyl group. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2016-181669 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] However, the light-emitting elements described above did not always have a sufficiently low driving voltage. Therefore, the present invention aims to provide a light-emitting element with a low driving voltage. [Means for solving the problem]

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

[12] . [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 phosphorescent compound and two or more compounds represented by formula (T-1), The second layer is a layer containing a crosslinked polymer compound which includes a structural unit having at least one crosslinking group selected from group A of crosslinking groups, Of the two or more compounds represented by formula (T-1) mentioned above, Ar in at least two of the compounds T2 However, if each of the compounds is independently a monocyclic and six-membered heterocyclic ring containing a group represented by =N- within the ring, then the light-emitting element comprises two compounds that satisfy at least one requirement selected from the group consisting of requirement (i) and requirement (ii). (i) The difference in the number of nitrogen atoms constituting the monocyclic and 6-membered heterocyclic ring containing a group represented by =N- within the ring is 2 or more. (ii) The difference in molecular weight is 80 or more. [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 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 context, a monovalent heterocyclic group is a monovalent heterocyclic group that contains a nitrogen atom that does not form a double bond within the ring, 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, and the monovalent heterocyclic group 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 together with the atom to which they are bonded. LT1 represents a divalent group, which may have substituents. When there are a plurality of the substituents, they may be the same or different, and may combine with each other to form a ring together with the atoms to which they are respectively attached. L T1 When there are a plurality of Ls, they may be the same or different, and they may combine with each other directly or through a divalent group 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 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 the substituents, they may be the same or different, and may combine with each other to form a ring together with the atoms to which they are respectively attached. n T2 represents an integer of 1 or more. However, when 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 through a divalent group to form a ring. Ar T2 and L T1 may be directly bonded or bonded through a divalent group to form a ring. Ar T1 and Ar T2 may be directly bonded or bonded through a divalent group to form a ring.]

Chemical formula

[10] The light-emitting element according to any one of [1] to [9], 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.

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

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

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

[11] , 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 a low driving voltage. [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. Furthermore, alkyl groups may be groups in which some or all of the hydrogen atoms in these groups are substituted with substituents (e.g., trifluoromethyl, pentafluoroethyl, perfluorobutyl, perfluorohexyl, perfluorooctyl, 3-phenylpropyl, 3-(4-methylphenyl)propyl, 3-(3,5-di-hexylphenyl) It may also be a propyl group or a 6-ethyloxyhexyl group.

[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 also 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 the "aryloxy group," excluding the number of carbon atoms of substituents, is usually 6 to 60, 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 dioxide, benzothiophene oxy Bicyclic heterocyclic compounds such as dibenzofuran, dibenzothiophene, dibenzothiophene dioxide, dibenzothiophene oxide, dibenzopyranone, dibenzobolol, dibenzosilol, dibenzophosphorus, dibenzoselenophene, carbazole, azacarbazole, diazacarbazole, phenoxazine, phenothiazine, 9,10-dihydroacridine, 5,10-dihydrophenazine, acridone, phenazavolin, phenophosphadin, phenoselenazine, phenazacillin, azaanthracene, diazaanthracene, azaphenanthrene and diazaphenanthrene; hexa Examples include tetracyclic heterocyclic compounds such as azatriphenylene, benzocarbazole, azabenzocarbazole, diazabenzocarbazole, benzonaphthofuran, and benzonaphthothiophene; pentacyclic heterocyclic compounds such as dibenzocarbazole, indolocarbazole, indenocarbazole, azaindolocarbazole, diazaindolocarbazole, azaindenocarbazole, and diazaindenocarbazole; hexacyclic heterocyclic compounds such as carbazolocarbazole, benzoindolocarbazole, and benzoindenocarbazole; and heptacyclic 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 said group are substituted with substituents. Heterocyclic groups include groups in which multiple such groups are bonded. Heterocyclic groups may have substituents.

[0029] Monovalent heterocyclic groups may have substituents. Examples of monovalent heterocyclic groups include thienyl, pyrrolyl, furyl, pyridyl, piperidinyl, quinolinyl, isoquinolinyl, pyrimidinyl, triazinyl, and groups in which some or all of the hydrogen atoms in these groups are substituted with substituents. Monovalent heterocyclic groups include groups formed by the bonding of multiple such groups.

[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 the branched alkynyl group, excluding the carbon atoms of substituents, is usually 4 to 50, preferably 4 to 20, and more preferably 4 to 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.

[0038] 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.

[0039] 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 selected from group X of crosslinking groups (i.e., a group represented by any of formulas (XL-1) to (XL-19)), and more preferably, a crosslinking group is selected from group A of crosslinking groups (i.e., a group represented by any of formulas (XL-1) to (XL-17)).

[0040] [ka]

[0041] [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.

[0042] 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.

[0043] 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.

[0044] In this specification, the energy levels of the lowest excited singlet state (S1) and lowest excited triplet state (T1) of a compound are determined by the following method. First, the ground state of the compound is structurally optimized using B3LYP-level density functional theory. 6-31G* is used as the basis set. Then, using the resulting structurally optimized structure, the lowest excited singlet state (S1) and lowest excited triplet state (T1) of the compound are calculated using B3LYP-level time-dependent density functional theory. However, if the compound contains atoms for which 6-31G* cannot be used, the energy levels of those atoms are determined accordingly. We will use LANL2DZ for this purpose. Furthermore, we will use Gaussian as the quantum chemistry calculation program.

[0045] <First layer> In the light-emitting element of this embodiment, the first layer is a layer containing a phosphorescent compound and two or more compounds represented by formula (T-1). The first layer may contain one phosphorescent compound alone, or two or more. The first layer may contain only two compounds represented by formula (T-1), or three or more.

[0046] In the light-emitting element of this embodiment, the number of types of compounds represented by formula (T-1) 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.

[0047] In the first layer, the total content of the phosphorescent compound and all compounds represented by formula (T-1) may be within a range that allows the first layer to function. In the first layer, the total content of the phosphorescent compound and all compounds represented by formula (T-1) may be, for example, 1 to 100% by mass based on 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 lowers the driving voltage of the light-emitting element in this embodiment.

[0048] In the first layer, the content of the phosphorescent compound should be within a range that allows the first layer to function as such. In the first layer, the content of the phosphorescent compound may be, for example, 0.01 to 99 parts by mass, with the total content of the phosphorescent compound and all compounds represented by formula (T-1) in the first layer being 100 parts by mass. Preferably, it is 0.1 to 90 parts by mass, more preferably 0.5 to 70 parts by mass, even more preferably 1 to 50 parts by mass, particularly preferably 2 to 30 parts by mass, and especially preferably 3 to 10 parts by mass, as this lowers the driving voltage of the light-emitting element in this embodiment.

[0049] In the first layer, the total content of all compounds represented by formula (T-1) is limited to a range that allows the first layer to function as such. In the first layer, the total content of all compounds represented by formula (T-1) may be, for example, 1 to 99.9 parts by mass, with the total content of phosphorescent compounds and all compounds represented by formula (T-1) in the first layer being 100 parts by mass. Preferably, it is 10 to 99.5 parts by mass, more preferably 30 to 99 parts by mass, even more preferably 50 to 98.5 parts by mass, particularly preferably 70 to 98 parts by mass, and especially preferably 90 to 97 parts by mass, as this lowers the driving voltage of the light-emitting element in this embodiment.

[0050] In the first layer, the content of each of the two or more compounds represented by formula (T-1) may be within a range that allows the first layer to function as such. In the first layer, the content of each compound represented by formula (T-1) may be 0.1 to 99.9 parts by mass, preferably 0.5 to 99.5 parts by mass, more preferably 1 to 99 parts by mass, even more preferably 2 to 98 parts by mass, and particularly preferably 3 to 97 parts by mass, with the total content of all compounds represented by formula (T-1) in the first layer being 100 parts by mass.

[0051] In the first layer, the total content of two of the two or more compounds represented by formula (T-1) is sufficient as long as it functions as the first layer. In the first layer, the total content of the two compounds with the highest content among the two or more compounds represented by formula (T-1) is: The total content of all compounds represented by formula (T-1) in the first layer is 100 parts by mass, for example, it may be 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.

[0052] In the first layer, it is preferable that the phosphorescent compound interacts physically, chemically, or electrically with the compound represented by formula (T-1). Furthermore, it is preferable that each of the two or more compounds represented by formula (T-1) interacts physically, chemically, or electrically in the first layer. 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 phosphorescent compound and the compound represented by formula (T-1) interact electrically, and by efficiently transferring electrical energy from the compound represented by formula (T-1) to the phosphorescent compound, the phosphorescent compound can be made to emit light more efficiently, and the driving voltage of the light-emitting element of this embodiment becomes lower. From the above viewpoint, since the driving voltage of the light-emitting element of this embodiment becomes lower in the first layer, it is preferable that the compound represented by formula (T-1) 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 driving voltage of the light-emitting element of this embodiment becomes lower, so it is preferable that the lowest excited singlet state (S1) of the compound represented by formula (T-1) is at a higher energy level than the lowest excited singlet state (S1) of the phosphorescent compound. From the above viewpoint, in the first layer, the driving voltage of the light-emitting element of this embodiment becomes lower, so it is preferable that the lowest excited triplet state (T1) of the compound represented by formula (T-1) is at a higher energy level than the lowest excited triplet state (T1) of the phosphorescent compound.

[0053] The compound represented by formula (T-1) is preferably one that is soluble in solvents capable of dissolving phosphorescent compounds, since the light-emitting device of this embodiment can be fabricated by a wet process.

[0054] Since the driving voltage of the light-emitting element in this embodiment is lower, it is preferable that the first layer is a layer containing a host material and a guest material. When the first layer is a layer containing a host material and a guest material, the first layer may contain one type of host material alone or two or more types, but it is preferable that it contains two or more types. Also, when the first layer is a layer containing a host material and a guest material, the first layer may contain one type of guest material alone or two or more types.

[0055] 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, 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 lowers the driving voltage of the light-emitting element of this embodiment.

[0056] 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. Preferably, the driving voltage of the light-emitting element of this embodiment is lower, so it is preferably 0.1 to 90 parts by mass, more preferably 0.5 to 70 parts by mass, even more preferably 1 to 50 parts by mass, particularly preferably 2 to 30 parts by mass, and especially preferably 3 to 10 parts by mass.

[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 compound represented by formula (T-1) in the first layer is preferably the host material, as this results in a lower driving voltage for the light-emitting element of this embodiment. In the light-emitting element of this embodiment, if the first layer is a layer containing a host material and a guest material, the phosphorescent compound in the first layer is preferably a guest material because it results in a lower driving voltage for the light-emitting element of this embodiment.

[0058] 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, and the driving voltage of the light-emitting element of this embodiment becomes lower. From the above viewpoint, in the light-emitting element of this embodiment, the driving voltage of the light-emitting element of this embodiment is lower, 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 material in the light-emitting element of this embodiment as an example, it is preferable that the guest material has light-emitting properties, since the driving voltage of the light-emitting element of this embodiment becomes lower. From the above viewpoint, in the light-emitting element of this embodiment, it is preferable that the lowest excited triplet state (T1) of the host material is at a higher energy level than the lowest excited triplet state (T1) of the guest material, since the driving voltage of the light-emitting element of this embodiment is lower. From the above viewpoint, in the light-emitting element of this embodiment, it is preferable that the lowest excited singlet state (S1) of the host material is at a higher energy level than the lowest excited singlet state (S1) of the guest material, since the driving voltage of the light-emitting element of this embodiment is lower.

[0059] 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.

[0060] [Compound represented by formula (T-1)] The molecular weight of the compound represented by formula (T-1) is preferably 200 to 10000, more preferably 300 to 3000, even more preferably 350 to 1500, and particularly preferably 400 to 1000. The compound represented by formula (T-1) is preferably a low molecular weight compound. Furthermore, the compound represented by formula (T-1) is preferably a compound that does not contain transition metal elements (i.e., a compound composed only of main group elements).

[0061] n T1 This is usually an integer between 0 and 10, and since the driving voltage of the light-emitting element in this embodiment becomes lower, it is preferably an integer between 0 and 5, and more preferably an integer between 0 and 3. It is a number, more preferably an integer between 0 and 2, and particularly preferably 0 or 1. n T2 This is usually an integer between 1 and 15, and since the driving voltage of the light-emitting element in this embodiment becomes low, it 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.

[0062] 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 .

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] The donor-type heterocyclic compound is preferably an aromatic heterocyclic compound, as this results in a lower driving voltage for the light-emitting element in this embodiment. The donor-type heterocyclic compound is preferably a polycyclic heterocyclic compound because it lowers the driving voltage of the light-emitting element in this embodiment. That is, a monovalent donor-type heterocyclic group lowers the driving voltage of the light-emitting element in this embodiment because it has nitrogen atoms that do not form a double bond in the ring. Preferably, the group is 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 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- within 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 particularly preferably a polycyclic heterocyclic compound containing both a 5-membered ring and a 6-membered ring. Examples of donor-type heterocyclic compounds containing a 5-membered ring or a 6-membered ring include the heterocyclic compounds containing a 5-membered ring or a 6-membered ring exemplified in the section on heterocyclic groups above. When the donor-type heterocyclic compound is a polycyclic heterocyclic compound, the donor-type 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, phenoxazine, 9,10-dihydroacridine, benzocarbazole, dibenzocarbazole, indolocarbazole, or indenocarbazole, and especially preferably carbazole, phenoxazine, 9,10-dihydroacridine, indolocarbazole, or indenocarbazole. When the donor heterocyclic compound is a monocyclic heterocyclic compound, an example of the donor heterocyclic compound is pyrrole.

[0068] 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.

[0069] 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, aryl groups, monovalent heterocyclic groups, or substituted amino groups; particularly preferably alkyl groups, cycloalkyl groups, aryl groups, or substituted amino groups, and these groups may further have substituents.

[0070] Ar T1The 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 lowers the driving voltage 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 from benzene, naphthalene, anthracene, phenanthrene, dihydrophenanthrene, or fluorene from which one hydrogen atom directly bonded to a carbon atom constituting the ring has been removed. Particularly preferably, it is a phenyl group, and these groups may have substituents.

[0071] Ar T1 As for the monovalent heterocyclic group in the substituent that may be present, since the driving voltage of the light-emitting element of this embodiment becomes lower, it is preferably a group obtained by removing one hydrogen atom directly bonded to the atoms constituting the ring from a monocyclic or bicyclic to hexacyclic heterocyclic compound, and more preferably a group obtained by removing one hydrogen atom directly bonded to the atoms constituting the ring from a monocyclic, bicyclic or tricyclic heterocyclic compound. A group from which one hydrogen atom is removed, and more preferably from furan, thiophene, oxadiazole, thiadiazole, pyrrole, diazole, triazole, pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, benzofuran, benzothiophene, indole, azaindole, diazaindole, benzodiazole, benzotriazole, dibenzofuran, dibenzothiophene, carbazole, azacarbazole, diazacarbazole, phenoxazine, phenothiazine, 9,10-dihydroacridine, 5,10-dihydrophenazine, acridone, azaanthracene, diazaanthracene, azaphenanthrene, or diazaphenanthrene, from which one hydrogen atom directly bonded to an atom constituting the ring is removed, and particularly preferably pyridine, diazabenzene, triazine, a The group is obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from zanafthalene, diazanaphthalene, dibenzofuran, dibenzothiophene, carbazole, azacarbazole, diazacarbazole, phenoxazine, phenothiazine, 9,10-dihydroacridine, or 5,10-dihydrophenazine, and is particularly 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.

[0072] Ar T1 In 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 T1It is the same as the examples and preferred ranges of the monovalent heterocyclic group in the substituent that may be possessed.

[0073] Ar T1 As the substituent that the substituent that may be possessed may further have, preferably a halogen atom, a cyano group, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryloxy group, an aryl group, a monovalent heterocyclic group or a substituted amino 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, a cycloalkyl group or an aryl group, particularly preferably an alkyl group or a cycloalkyl group, and these groups may further have a substituent, but it is preferable not to have a further substituent. Ar T1 Examples and preferred ranges of the aryl group, monovalent heterocyclic group and substituted amino group in the substituent that the substituent that may be possessed may further have are, respectively, the same as those of the aryl group, monovalent heterocyclic group and substituted amino group in the substituent that Ar T1 may have.

[0074] Ar T1 At least one of them is preferably a monovalent donor-type heterocyclic group that may have a substituent because the driving voltage of the light-emitting element of this embodiment becomes lower. Ar T1 is preferably a monovalent donor-type heterocyclic group that may have a substituent because the driving voltage of the light-emitting element of this embodiment becomes further lower.

[0075] Ar T1 When a plurality of them exist, they may be the same or different, and they may be bonded to each other directly or via a divalent group to form a ring, but it is preferable not to form a ring because the synthesis of the compound represented by the formula (T-1) is easy. Ar T1When there are a plurality of them and they are bonded 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, -N(R T1 ’)-represented group, -B(R T1 ’)-represented group, 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, a group represented by -N(R T1 ’)-represented group, a group represented by -B(R T1 ’)-represented group, a group represented by -O- or a group represented by -S-, still more preferably an alkylene group, a group represented by -O- or a group represented by -S-, and these groups may have substituents.

[0076]

[0077] In the divalent group, the arylene group is preferably a group obtained by removing two hydrogen atoms directly bonded to the carbon 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 carbon atoms constituting the ring from a monocyclic, bicyclic or tricyclic aromatic hydrocarbon, still more preferably a group obtained by removing two hydrogen atoms directly bonded to the carbon atoms constituting the ring from benzene, naphthalene, anthracene, phenanthrene, dihydrophenanthrene or fluorene, particularly preferably a group obtained by removing two hydrogen atoms directly bonded to the carbon atoms constituting the ring from benzene, naphthalene or fluorene, and 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.

[0078] 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.

[0079] 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, even more preferably an aryl group or a monovalent heterocyclic group, and particularly preferably an aryl group, and these groups may have substituents. R T1 Examples and preferred ranges of substituents that ' may have are Ar T1 The examples and preferred ranges of substituents that may be present are the same as those mentioned above. R T1 Examples and preferred ranges of aryl groups, monovalent heterocyclic groups, and substituted amino groups in ' 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.

[0080] L T1 In this case, the divalent group results in a lower driving voltage for the light-emitting element of this embodiment. Preferably alkylene group, cycloalkylene group, arylene group, divalent heterocyclic group, -N(R T1 A base represented by ')-, -B(R T1 The group is represented by -)-, -O-, -S-, -C(=O)-, or -S(=O)2-, 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-, even more preferably an alkylene group, a cycloalkylene group, an arylene group, or 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 substituents that may be present are Ar T1 The examples and preferred ranges of substituents that may be present are the same as those mentioned above. 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.

[0081] 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 driving voltage of the light-emitting element of this embodiment is lower, so preferably the aromatic hydrocarbon group is 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, more preferably 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, and even more preferably a monocyclic aromatic hydrocarbon from which one or more hydrogen atoms directly bonded to the atoms constituting the ring have been removed, and 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 lowers the driving voltage of the light-emitting element in 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.

[0082] 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 T2 In this context, as an aromatic hydrocarbon group containing a -C(=O)- group within the ring Examples of aromatic hydrocarbon groups include those described in the section on aromatic hydrocarbon groups above, which include an aromatic hydrocarbon group containing a group represented by -C(=O)- in the ring, preferably a bicyclic or tricyclic aromatic hydrocarbon containing a group represented by -C(=O)- in the ring, from which one or more hydrogen atoms directly bonded to the atoms constituting the ring have been removed, more preferably a group from naphthoquinone, anthraquinone, phenanthrenequinone, indenone, fluorenone, or tetralone from which one or more hydrogen atoms directly bonded to the atoms constituting the ring have been removed, and these groups may have substituents.

[0083] 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")" means a group obtained by removing one or more hydrogen atoms directly bonded to the atoms constituting the ring (carbon atoms or heteroatoms, preferably carbon atoms) from a heterocyclic compound 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 compound"). Examples of acceptor-type heterocyclic compounds include heterocyclic compounds described in the section on heterocyclic groups above, which contain 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- within the ring. Groups of acceptor-type heterocyclic compounds, excluding one or more hydrogen atoms directly bonded to the atoms constituting the ring, may have substituents.

[0084] 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.

[0085] The acceptor-type heterocyclic compound is preferably an aromatic heterocyclic compound because it results in a lower driving voltage for the light-emitting element in this embodiment. The acceptor-type heterocyclic compound is preferably a 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)-, and a group represented by -S(=O)2-, since the driving voltage of the light-emitting element of this embodiment becomes lower, and more preferably a heterocyclic compound that contains a group represented by =N- in 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 this results in a lower driving voltage for the light-emitting element of this embodiment. The acceptor-type heterocyclic compound is preferably a heterocyclic compound containing a 5-membered ring or a 6-membered ring, and more preferably a heterocyclic compound containing a 6-membered ring, because it lowers the driving voltage of the light-emitting element in this embodiment. 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.

[0086] The acceptor-type heterocyclic group is preferable because it further lowers the driving voltage of the light-emitting element in this embodiment. It is preferably 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 oxide, 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, di The group is obtained by removing one or more hydrogen atoms directly bonded to the ring-forming atoms (preferably carbon atoms) from dibenzothiophene dioxide, dibenzothiophene oxide, or dibenzopyranone; more preferably, the group is obtained by removing one or more hydrogen atoms directly bonded to the ring-forming atoms (preferably carbon atoms) 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 the ring-forming atoms from triazole (preferably 1,2,4-triazole), pyridine, diazabenzene (preferably pyrimidine), or triazine; these groups may have substituents.

[0087] Ar T2 The driving voltage of the light-emitting element in this embodiment is lower, so preferably the group is 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 an aromatic hydrocarbon group having an electron-withdrawing group, or an acceptor-type heterocyclic group, and these groups may have substituents. Ar T2Since the driving voltage of the light-emitting element of this embodiment becomes even lower, it is preferably 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 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 these groups may have substituents.

[0088] 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.

[0089] 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.

[0090] 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 the substituent is a monovalent heterocyclic group other than a monovalent donor-type heterocyclic group, and the group 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 heterocyclic compound, preferably a monocyclic or bicyclic to hexacyclic compound, as 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 the atoms 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, azanaflane, diazanaphthalene, benzofuran, benzothiophene, azaindole, diazindole, benzodiazole, benzotriazole, dibenzofuran, dibenzothiophene, azacarbazole, diaza The group is obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from carbazole, 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, dizanaphthalene, 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 Ar 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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 T1Examples and preferred ranges of the divalent group in the case where “-” is bonded via a divalent group to form a ring are Ar T1 When there are a plurality of them and they are bonded to each other via a divalent group to form a ring, they are the same as the examples and preferred ranges of the divalent group in this case.

[0095] Ar T2 and R T1 ‘ may be directly bonded or bonded via a divalent group to form a ring, but since the synthesis of the compound represented by formula (T-1) is easy, it is preferred not to form a ring. Ar T2 and R T1 ‘ are bonded via a divalent group to form a ring. Examples and preferred ranges of the divalent group in this case are Ar T1 When there are a plurality of them and they are bonded to each other via a divalent group to form a ring, they are the same as the examples and preferred ranges of the divalent group in this case.

[0096] Examples of the compound represented by formula (T-1) include, for example, compounds represented by the following formula. In the formula, Z 1 represents a group represented by -N= or a group represented by -CH=. However, in each of the compounds represented by the following formula listed as the compound represented by formula (T-1), at least one of Z 1 represents a group represented by -N=. Z 2 represents an oxygen atom or a sulfur atom. Z 3 represents a group represented by -C(=O)- or a group represented by -S(=O)2-. Z 1 , Z 2 and Z 3 When there are a plurality of them, they may be the same or different from each other.

[0097]

Chemical formula

[0098]

Chemical formula

[0099]

change

[0100]

change

[0101]

change

[0102]

change

[0103]

change

[0104]

change

[0105]

change

[0106]

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[0107]

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[0108]

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[0109] In the first layer, Ar is present in at least two of the compounds represented by formula (T-1) T2 However, if each is independently a monocyclic and six-membered heterocyclic ring containing a group represented by =N- within the ring, and one or more hydrogen atoms have been removed, then the at least two compounds include two compounds that satisfy at least one requirement selected from the group consisting of requirement (i) and requirement (ii), and preferably two compounds that satisfy requirement (i) and requirement (ii), so that the driving voltage of the light-emitting element of this embodiment becomes lower. Examples of monocyclic, six-membered heterocyclic rings containing a group represented by =N- within the ring include pyridine, diazabenzene (preferably pyrimidine), or triazine, and these rings may have substituents.

[0110] In the first layer, Ar is present in at least two of the compounds represented by formula (T-1) T2 However, each is independently a monocyclic and six-membered heterocyclic ring containing a group represented by =N- within the ring, with one or more hydrogen atoms removed, and if at least two of these compounds include two compounds that satisfy requirement (i), the first layer may contain only two compounds in a combination that satisfies requirement (i), or it may contain three or more compounds that include two or more combinations that satisfy requirement (i). Since the light-emitting element of this embodiment is easy to manufacture, it is preferable that it contains only two compounds in a combination that satisfies requirement (i).

[0111] In the first layer, Ar is present in at least two of the compounds represented by formula (T-1) T2 However, each is independently a group obtained by removing one or more hydrogen atoms from a monocyclic and six-membered heterocyclic ring containing a group represented by =N- within the ring, and if the at least two of these compounds include two compounds that satisfy requirement (i), the difference in the number of nitrogen atoms constituting the monocyclic and six-membered heterocyclic ring containing a group represented by =N- within the ring of the two compounds is usually 2 or more, and the driving voltage of the light-emitting element of this embodiment becomes lower, so it is preferably 2 to 5, more preferably 2 or 3, and even more preferably 2.

[0112] In the first layer, Ar is present in at least two of the compounds represented by formula (T-1) T2 However, each is independently a monocyclic and six-membered heterocyclic ring containing a group represented by =N- within the ring, with one or more hydrogen atoms removed, and if at least two of these compounds include two compounds that satisfy requirement (ii), the first layer may contain only two compounds in a combination that satisfies requirement (ii), or it may contain three or more compounds that include two or more combinations that satisfy requirement (ii). Since the light-emitting element of this embodiment is easy to manufacture, it is preferable to contain only two compounds in a combination that satisfies requirement (ii).

[0113] In the first layer, Ar is present in at least two of the compounds represented by formula (T-1) T2 However, each is independently a monocyclic and six-membered heterocyclic ring containing a group represented by =N- within the ring, with one or more hydrogen atoms removed. And if at least two of these compounds include two compounds that satisfy requirement (ii), the difference in molecular weight of the two compounds is usually 80 or more, and since the driving voltage of the light-emitting element of this embodiment becomes lower, it may be 90 or more, 100 or more, 110 or more, 120 or more, 130 or more, 140 or more, or 150 or more.

[0114] In the first layer, Ar is present in at least two of the compounds represented by formula (T-1) T2 However, each is independently a monocyclic and six-membered heterocyclic ring containing a group represented by =N- within the ring, with one or more hydrogen atoms removed, and if at least two of these compounds include two compounds that satisfy requirement (ii), the difference in molecular weight of the two compounds is usually 1000 or less, but may be 500 or less, 400 or less, 350 or less, 300 or less, 250 or less, or 200 or less.

[0115] 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, and to result in a lower driving voltage in the light-emitting element of this embodiment. Furthermore, among the two or more compounds represented by formula (T-1), Ar is present in at least two of the compounds. T2 However, if each group is independently a monocyclic and six-membered heterocyclic ring containing a group represented by =N- within the ring, and if the compounds represented by formula (T-1) include two or more similar compounds such that the difference in the number of nitrogen atoms constituting the monocyclic and six-membered heterocyclic ring containing a group represented by =N- within the ring and / or the difference in molecular weight are within the above range, then the compatibility is improved, and the properties of the first layer film are improved, which tends to lower the driving voltage of the light-emitting element of this embodiment.

[0116] [Phosphorescent compounds] The term "phosphorescent compound" usually refers to a compound that exhibits phosphorescence at room temperature, but preferably, it refers to a metal complex that exhibits luminescence from a triplet excited state at room temperature. A metal complex that exhibits luminescence from a triplet excited state at room temperature usually has a central metal atom and ligands.

[0117] In a metal complex that exhibits luminescence from a triplet excited state at room temperature, the central metal atom may be, for example, an atom with an atomic number of 40 or higher, which has spin-orbit interaction in the complex and can undergo intersystem crossing between the singlet and triplet states. Examples of metal atoms include ruthenium, rhodium, palladium, iridium, platinum, and europium atoms, and iridium or platinum atoms are preferred because they result in a lower driving voltage for the light-emitting element in this embodiment.

[0118] In metal complexes that exhibit luminescence from a triplet excited state at room temperature, the number of central metal atoms in the metal complex is usually 1 to 5, preferably 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0119] In metal complexes that exhibit luminescence from a triplet excited state at room temperature, examples of ligands include neutral or anionic monodentate ligands, or neutral or anionic polydentate ligands, that form at least one bond selected from the group consisting of coordinate bonds and covalent bonds with the central metal atom. Examples of bonds between the central metal atom and the ligand include metal-nitrogen bonds, metal-carbon bonds, metal-oxygen bonds, metal-phosphorus bonds, metal-sulfur bonds, and gold bonds. A group-halogen bond is one example. A polydentate ligand usually refers to a ligand with two to six dentates.

[0120] The molecular weight of the phosphorescent compound is preferably 2 × 10⁻⁶ 2 ~1 × 10 4 And more preferably, 4 × 10 2 ~7×10 3 Yes, and more preferably 6 × 10 2 ~5×10 3 And, particularly preferably, 8 × 10 2 ~3×10 3 The phosphorescent compound is preferably a low-molecular-weight compound.

[0121] (Metal complex represented by formula (1)) The phosphorescent compound is preferably a metal complex represented by formula (1) because it allows for a lower driving voltage of the light-emitting element in this embodiment. M is preferably an iridium atom or a platinum atom, and more preferably an iridium atom, because the driving voltage of the light-emitting element in this embodiment becomes lower. If M is a rhodium atom or an iridium atom, n 1 It is preferably 2 or 3, and more preferably 3. If M is a palladium atom or a platinum atom, then n 1It is preferable that it is 2.

[0122] Since the metal complex represented by formula (1) can be easily synthesized, E 1 and E 2 Preferably, at least one of them is a carbon atom, E 1 and E 2 It is more preferable that it be a carbon atom. Since the metal complex represented by formula (1) can be easily synthesized, E 1 and E 2 They are preferably the same. Also, since the metal complex represented by formula (1) can be easily synthesized, E 1 If multiple are present, they are preferably identical. Also, since the metal complex represented by formula (1) can be easily synthesized, E 2 If multiple instances exist, they are preferably identical.

[0123] Ring L 1 The number of carbon atoms in the aromatic heterocycle in ring L is usually 1 to 60, preferably 2 to 30, more preferably 3 to 20, even more preferably 4 to 10, and particularly preferably 5 to 9, not including the number of carbon atoms of substituents. 1 The number of heteroatoms in the aromatic heterocycle in ring L is usually 1 to 30, preferably 1 to 10, more preferably 1 to 5, even more preferably 1 to 3, and particularly preferably 1, not including the number of heteroatoms of substituents. 1 The number of nitrogen atoms in the aromatic heterocycle, not including the number of nitrogen atoms of substituents, is usually 1 to 30, preferably 1 to 10, more preferably 1 to 5, even more preferably 1 to 3, particularly preferably 1 or 2, and especially preferably 1.

[0124] Ring L 1 Examples of aromatic heterocycles in this context include aromatic heterocycles among those exemplified in the section on heterocyclic groups mentioned above, which contain one or more nitrogen atoms within the ring, and such aromatic heterocycles may have substituents.

[0125] Ring L 1Since the driving voltage of the light-emitting element of this embodiment is lower, it is preferably an aromatic heterocycle containing one or more nitrogen atoms and a 5-membered ring or a 6-membered ring, and more preferably an aromatic heterocycle containing one or more nitrogen atoms and a 6-membered ring, and these rings may have substituents. Alternatively, ring L 1 Since the driving voltage of the light-emitting element of this embodiment is lower, preferably the ring contains one or more nitrogen atoms and is a monocyclic or 2- to 7-cyclic aromatic heterocycle, more preferably it contains one or more nitrogen atoms and is a monocyclic or 2- to 5-cyclic aromatic heterocycle, even more preferably it contains one or more nitrogen atoms and is a monocyclic, 2-cyclic or 3-cyclic aromatic heterocycle, particularly preferably it contains one or more nitrogen atoms and is a monocyclic or 2- to 5-cyclic aromatic heterocycle, and these rings may have substituents.

[0126] Ring L 1 The driving voltage of the light-emitting element in this embodiment is further reduced, so preferably the ring is a pyridine ring, a diazabenzene ring, an azanaphthalene ring, a triazole ring, or a diazole ring, more preferably a pyridine ring, a diazabenzene ring, an azanaphthalene ring, or a diazanaphthalene ring, even more preferably a pyridine ring or an azanaphthalene ring, and particularly preferably a pyridine ring, and these rings may have substituents.

[0127] Since the metal complex represented by formula (1) can be easily synthesized, ring L 1 If multiple rings exist, then multiple rings L exist. 1 Preferably, at least two of these are identical, and there are multiple rings L. 1 It is preferable that all of them are identical.

[0128] Ring L 2The number of carbon atoms in the aromatic hydrocarbon ring, excluding the number of carbon atoms of substituents, is preferably 6 to 40, more preferably 6 to 20, and even more preferably 6 to 10.

[0129] Ring L 2 Examples of aromatic hydrocarbon rings in this context include the aromatic hydrocarbon rings exemplified in the section on aromatic hydrocarbon groups mentioned above, and these aromatic hydrocarbon rings may have substituents.

[0130] Ring L 2 The aromatic hydrocarbon ring in this embodiment is preferably an aromatic hydrocarbon ring containing a 5-membered ring or a 6-membered ring, more preferably an aromatic hydrocarbon ring containing a 6-membered ring, as this results in a lower driving voltage for the light-emitting element of this embodiment. These rings may have substituents. Ring L 2 The aromatic hydrocarbon ring in this embodiment is preferably a monocyclic, bicyclic, or tricyclic aromatic hydrocarbon ring, particularly preferably a benzene ring, naphthalene ring, fluorene ring, phenanthrene ring, or dihydrophenanthrene ring, especially preferably a benzene ring, fluorene ring, or dihydrophenanthrene ring, and more particularly preferably a benzene ring. These rings may have substituents.

[0131] Ring L 2 The number of carbon atoms in the aromatic heterocycle in ring L is preferably 1 to 30, more preferably 2 to 20, and even more preferably 3 to 10, not including the number of carbon atoms of substituents. 2 The number of heteroatoms in the aromatic heterocycle is preferably 1 to 10, more preferably 1 to 5, and even more preferably 1 to 3, not including the number of heteroatoms of substituents.

[0132] Ring L 2 Examples of aromatic heterocycles in this context include the aromatic heterocycles exemplified in the section on heterocyclic groups mentioned above, and these aromatic heterocycles may have substituents. Ring L 2The aromatic heterocycle in this embodiment is preferably a monocyclic, bicyclic, or tricyclic aromatic heterocycle, more preferably a pyridine ring, diazabenzene ring, azananaphthalene ring, diazananaphthalene ring, indole ring, benzofuran ring, benzothiophene ring, carbazole ring, azacarbazole ring, diazacarbazole ring, dibenzofuran ring, or dibenzothiophene ring, even more preferably a pyridine ring, diazabenzene ring, carbazole ring, dibenzofuran ring, or dibenzothiophene ring, and particularly preferably a pyridine ring or a diazabenzene ring, and these rings may have substituents.

[0133] Ring L 2 The driving voltage of the light-emitting element in this embodiment is lower, so preferably it is a benzene ring, a pyridine ring, or a diazabenzene ring, more preferably a benzene ring, and these rings may have substituents.

[0134] Since the metal complex represented by formula (1) can be easily synthesized, ring L 2 If there are multiple instances, There are several rings L 2 Preferably, at least two of these are identical, and there are multiple rings L. 2 It is preferable that all of them are identical.

[0135] Since the driving voltage of the light-emitting element in this embodiment becomes even lower, ring L 1 The ring L is a pyridine ring, a diazabenzene ring, an azanaphthalene ring, a triazole ring, or a diazole ring, and the ring L 2 Preferably, the ring L is a benzene ring, a pyridine ring, or a diazabenzene ring. 1 The ring L is a pyridine ring, an azanaphthalene ring, a triazole ring, or a diazole ring, and the ring L 2 It is more preferable that the ring L is a benzene ring. 1 The ring L is a pyridine ring or an azanaphthalene ring, and the ring L is a pyridine ring or an azanaphthalene ring. 2 It is even more preferable that the ring L is a benzene ring. 1 is a pyridine ring, and ring L2 It is particularly preferable that the rings are benzene rings, and these rings may have substituents.

[0136] Ring L 1 and ring L 2 The substituents that may be present (hereinafter also referred to as "primary substituents") are preferably alkyl groups, cycloalkyl groups, alkoxy groups, cycloalkoxy groups, aryl groups, aryloxy 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, aryl groups, or monovalent heterocyclic groups; particularly preferably alkyl groups or aryl groups; and these groups may further have substituents (hereinafter also referred to as "secondary substituents").

[0137] Since the driving voltage of the light-emitting element in this embodiment becomes lower, ring L 1 and ring L 2 It is preferable that at least one of these molecules has a substituent.

[0138] In the metal complex represented by formula (1), ring L 1 and ring L 2 At least one of them has a primary substituent, and ring L 1 and ring L 2 If multiple rings exist, then multiple rings L exist. 1 and ring L 2 It is sufficient that at least one of the rings has a primary substituent, but the driving voltage of the light-emitting element in this embodiment is lower, so multiple rings L 1 and ring L 2 Preferably, at least two of the rings have primary substituents, and there are multiple rings L 1 and ring L 2 It is more preferable that at least three of them have primary substituents. Also, in the metal complex represented by formula (1), ring L 1 and ring L 2 At least one of them has a primary substituent, and ring L 1 and ring L 2If multiple rings L exist, the driving voltage of the light-emitting element in this embodiment will be lower, so multiple rings L 1 At least two of the rings have primary substituents, or there are multiple rings L. 2 Preferably, at least two of the rings have primary substituents, and there are multiple rings L 1 All of them have primary substituents, or multiple rings L 2 It is more preferable that all of them have primary substituents.

[0139] In the metal complex represented by formula (1), ring L 1 and ring L 2 If at least one of them has a primary substituent, then ring L 1 and ring L 2 The number of primary substituents on at least one of these is usually 1 to 10, which allows for easy synthesis of the metal complex represented by formula (1), and also lowers the driving voltage of the light-emitting element of this embodiment. Therefore, it is preferably 1 to 5, more preferably 1 to 3, even more preferably 1 or 2, and particularly preferably 1.

[0140] In the metal complex represented by formula (1), ring L 1 and ring L 2 If at least one of them has a primary substituent and M is a rhodium atom or an iridium atom, then ring L 1 and ring L 2 The total number of primary substituents is usually 1 to 30, and is preferably 1 to 18, more preferably 2 to 12, and even more preferably 3 to 6, as this allows for easy synthesis of the metal complex represented by formula (1) and lowers the driving voltage of the light-emitting element of this embodiment.

[0141] In the metal complex represented by formula (1), ring L 1 and ring L 2 If at least one of them has a primary substituent and M is a palladium atom or a platinum atom, then ring L 1 and ring L 2The total number of primary substituents is usually 1 to 20, and is preferably 1 to 12, more preferably 1 to 8, and even more preferably 2 to 4, as this allows for easy synthesis of the metal complex represented by formula (1) and lowers the driving voltage of the light-emitting element of this embodiment.

[0142] The alkyl group in the primary substituent is preferably a methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, or octyl group, more preferably a methyl group, butyl group, or hexyl group, and even more preferably a hexyl group.

[0143] The aryl group in the primary substituent is preferably a phenyl group, naphthyl group, phenantrenyl group, dihydrophenantrenyl group, or fluorenyl group, more preferably a phenyl group or fluorenyl group, and even more preferably a phenyl group. These groups may have substituents.

[0144] The monovalent heterocyclic group in the primary substituent is preferably a pyridyl group, pyrimidinyl group, triazinyl group, quinolinyl group, isoquinolinyl group, dibenzofuranyl group, dibenzothienyl group, carbazolyl group, azacarbazolyl group, diazacarbazolyl group, phenoxazinyl group, or phenothiazinyl group; more preferably a pyridyl group, pyrimidinyl group, triazinyl group, dibenzofuranyl group, dibenzothienyl group, or carbazolyl group; even more preferably a pyridyl group, pyrimidinyl group, or triazinyl group; and particularly preferably a triazinyl group. These groups may have substituents.

[0145] In the substituted amino group in the primary substituent, 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 given for ring L. 1 and ring L 2 The examples and preferred ranges of aryl groups in substituents that may be present are the same as those for ring L.1 and ring L 2 The examples and preferred ranges of monovalent heterocyclic groups in substituents that may be present are the same as those mentioned above.

[0146] Examples and preferred ranges of secondary substituents (substituents that the primary substituent may further have) are the same as examples and preferred ranges of primary substituents. The secondary substituent may have further substituents (hereinafter also referred to as "tertiary substituents"). Examples and preferred ranges of tertiary substituents (substituents that the secondary substituent may have further) are the same as examples and preferred ranges of primary substituents. The tertiary substituent may have further substituents (hereinafter also referred to as "quaternary substituents"). The quaternary substituent (substituents that the tertiary substituent may have) is preferably an alkyl group, cycloalkyl group, alkoxy group, cycloalkoxy group, aryl group, aryloxy group, monovalent heterocyclic group, substituted amino group, or fluorine atom; more preferably an alkyl group, cycloalkyl group, aryl group, monovalent heterocyclic group, or substituted amino group; even more preferably an alkyl group, cycloalkyl group, or aryl group; particularly preferably an alkyl group or cycloalkyl group. These groups may have further substituents, but it is preferable that they do not have further substituents so that the metal complex represented by formula (1) can be easily synthesized. Examples and preferred ranges of aryl groups, monovalent heterocyclic groups, and substituted amino groups in secondary, tertiary, and quaternary substituents are the same as examples and preferred ranges of aryl groups, monovalent heterocyclic groups, and substituted amino groups in primary substituents, respectively.

[0147] • Anionic bidentate ligand A 1 -G 1 -A 2 An example of an anionic bidentate ligand represented by is the ligand represented by the following formula. However, A 1 -G 1 -A 2 The anionic bidentate ligand represented by the subscript n 1 This is different from the ligands whose number is defined.

[0148] [ka]

[0149] [ka]

[0150] Examples of phosphorescent compounds include metal complexes represented by the following formula. Note that Z 1 and Z 2 This expresses the same meaning as above.

[0151] [ka]

[0152] [ka]

[0153] [ka]

[0154] [ka]

[0155] [ka]

[0156] [ka]

[0157] [First composition] The first layer may contain a composition (hereinafter also referred to as "the first composition") comprising a phosphorescent compound, two or more compounds represented by formula (T-1), 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 phosphorescent compound and the compound represented by formula (T-1).

[0158] (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; side chains or main Examples include polyarylenes and derivatives thereof having aromatic amine structures in their chains. The polymeric compounds may also be compounds to which electron-accepting sites are attached. Examples of electron-accepting sites include fullerenes, tetrafluorotetracyanoquinodimethane, tetracyanoethylene, and trinitrofluorenone.

[0159] 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 phosphorescent compound and all compounds represented by formula (T-1) is 100 parts by mass. The hole transport material may be used alone or in combination of two or more types.

[0160] (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.

[0161] 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.

[0162] In the first composition, if an electron transport material is included, the amount of the electron transport material is usually 1 to 400 parts by mass, preferably 5 to 150 parts by mass, when the total of the phosphorescent compound and all compounds represented by formula (T-1) is 100 parts by mass. Electron transport materials may be used individually or in combination of two or more types.

[0163] (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.

[0164] 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.

[0165] 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.

[0166] 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 phosphorescent compound and all compounds represented by formula (T-1) 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.

[0167] 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 of a conductive polymer, an appropriate amount of ions can be doped into the conductive polymer. Cut.

[0168] 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.

[0169] (Luminescent material) Luminescent materials are classified into low-molecular-weight compounds and high-molecular-weight compounds. Luminescent materials may also have crosslinking groups. The light-emitting material is preferably a fluorescent compound.

[0170] Examples of low molecular weight compounds include naphthalene and its derivatives, anthracene and its derivatives, and perylene and its derivatives.

[0171] 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.

[0172] 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 phosphorescent compound and all compounds represented by formula (T-1) is 100 parts by mass. The light-emitting material may be used alone or in combination of two or more types.

[0173] (Antioxidant) The antioxidant can be any compound that is soluble in the same solvent as the phosphorescent compound and the compound represented by formula (T-1) and does not inhibit luminescence and charge transport. Examples include phenolic antioxidants and phosphorus-based antioxidants.

[0174] 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 phosphorescent compound and all compounds represented by formula (T-1) is 100 parts by mass. Antioxidants may be used individually or in combination of two or more types.

[0175] [First Ink] The first layer can be formed, for example, using a composition (hereinafter also referred to as "first ink") containing a phosphorescent compound, two or more compounds represented by formula (T-1), 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.

[0176] 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.

[0177] 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.

[0178] 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 phosphorescent compounds and all compounds represented by formula (T-1) is 100 parts by mass.

[0179] <Second Layer> In the light-emitting element of this embodiment, the second layer is a layer containing a crosslinked polymer compound (hereinafter also referred to as "the polymer compound of the second layer") which includes a structural unit having at least one crosslinking group selected from group A of crosslinking groups. The second layer may contain only one type of crosslinked polymer compound of the second layer, or it may contain two or more types.

[0180] In the light-emitting element of this embodiment, the type of crosslinked polymer compound of the second layer contained 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.

[0181] In the second layer, the content of the crosslinked polymer compound in the second layer is limited to a range that allows the second layer to function as such. The content of the crosslinked polymer compound in the second layer may be 1 to 100% by mass based on the total amount of the second 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 lowers the driving voltage of the light-emitting element in this embodiment.

[0182] [Cross-linked polymer compound in the second layer] The crosslinked polymer compound of the second layer is obtained by crosslinking the polymer compound of the second layer using the methods and conditions described later. In this embodiment, the film quality of the second layer is considered to be improved by including a crosslinked polymer compound in which a specific crosslinking group (a crosslinking group selected from group A) is crosslinked in the second layer. This improvement in film quality is thought to improve the light emission characteristics, charge transport characteristics, or charge injection characteristics of the light-emitting element of this embodiment, and thus the driving voltage of the light-emitting element of this embodiment is considered to be lower.

[0183] From the above perspective, in the polymer compound of the second layer, a crosslinking group selected from group A of crosslinking groups and Therefore, the crosslinking properties of the polymer compound in the second layer are better, and the driving voltage of the light-emitting element of this embodiment is lower. Preferably, the crosslinking group is represented by formula (XL-1), formula (XL-9), formula (XL-10), formula (XL-16), or formula (XL-17), more preferably by formula (XL-1), formula (XL-16), or formula (XL-17), and even more preferably by formula (XL-1). 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. The polymer compound of the second layer may contain only one crosslinking group selected from group A, or it may contain two or more.

[0184] (A constituent unit having at least one type of crosslinking group selected from group A of crosslinking groups) The content of constituent units having at least one crosslinking group selected from group A in the polymer compound of the second layer is usually 0.1 to 100 mol% of the total amount of constituent units contained in the polymer compound of the second layer, but the stability and crosslinkability of the polymer compound of the second layer are low, so it is 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%. The polymer compound of the second layer may contain only one or more structural units having at least one crosslinking group selected from group A.

[0185] A component having at least one type of crosslinking group selected from group A is preferably a component represented by formula (Z) or formula (Z'), since this results in a lower driving voltage for the light-emitting element of this embodiment.

[0186] • 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 results in a lower driving voltage for the light-emitting element in this embodiment. nA is usually an integer between 0 and 10, and since the driving voltage of the light-emitting element in this embodiment is lower, it 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.

[0187] 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.

[0188] Ar 3 Examples 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.

[0189] 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 below in Ar Y1 Examples and preferred ranges of arylene groups in this context are given.

[0190] Ar 3Examples 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.

[0191] 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 to The examples and preferred ranges of hydrocarbon groups and heterocyclic groups are the same as those for the hydrocarbon groups and heterocyclic groups. 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.

[0192] Ar 3 Since the driving voltage of the light-emitting element in this embodiment becomes lower, the group is preferably a hydrocarbon group or a heterocyclic group, more preferably a hydrocarbon group, and even more preferably an aromatic hydrocarbon group, and these groups may have substituents.

[0193] L A Examples 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 driving voltage of the light-emitting element of this embodiment becomes lower, L A The arylene group represented by is preferably a phenylene group or a fluoroorangeyl group, and these groups may have substituents.

[0194] 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.

[0195] 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.

[0196] 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.

[0197] Ar 3 , L A Examples and preferred ranges of substituents that the group represented by and R' may have are described below in Ar Y1 The examples and preferred ranges of substituents that the group represented by may have are the same. The examples and preferred ranges of crosslinking groups selected from group A in X are the same as the examples and preferred ranges of crosslinking groups selected from group A in the polymer compound of the second layer.

[0198] The constituent unit represented by formula (Z) has excellent stability and crosslinkability in the polymer compound of the second layer, so it is preferably 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 of the second layer.

[0199] The constituent unit represented by formula (Z) may be present in the polymer compound of the second layer as one type or as two or more types.

[0200] · Constituent units represented by equation (Z') mA is usually an integer between 0 and 10, and since the driving voltage of the light-emitting element in this embodiment is lower, it 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. m is usually an integer between 0 and 10, and since the driving voltage of the light-emitting element in this embodiment is lower, it 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. 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 lowers the driving voltage of the light-emitting element in this embodiment.

[0201] 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.

[0202] Ar 5 Since the driving voltage of the light-emitting element in this embodiment becomes lower, the group is preferably a hydrocarbon group or a heterocyclic group, more preferably a hydrocarbon group, and even more preferably an aromatic hydrocarbon group, and these groups may have substituents.

[0203] Ar 4 and Ar 6 This is preferably an arylene group which may have substituents, as this lowers the driving voltage of the light-emitting element in 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.

[0204] 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'.

[0205] The examples and preferred ranges of crosslinking groups selected from group A in X' are the same as the examples and preferred ranges of crosslinking groups selected from group A represented by X. Examples and preferred ranges of aryl groups and monovalent heterocyclic groups in X' are given below in R X1 , R X2 and R X3 The examples and preferred ranges of aryl groups and monovalent heterocyclic groups are the same as those in [the relevant section].

[0206] X' is preferably a bridging group selected from group A, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group; more preferably a bridging group selected from group A, an aryl group, or a monovalent heterocyclic group; even more preferably a bridging group selected from group A or an aryl group; these groups may have substituents. Examples and preferred ranges of substituents that the group represented by X' may have are shown below in ArY1 The examples and preferred ranges of substituents that the group represented by may have are the same.

[0207] The constituent unit represented by formula (Z') has excellent stability and crosslinkability in the polymer compound of the second layer, so it 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 of the second layer. The constituent unit represented by formula (Z') may be present in the polymer compound of the second layer as one type or as two or more types.

[0208] A constituent unit having at least one type of crosslinking group selected from group A of crosslinking groups is, for example, The constituent units are shown in the following formula. Note that Z 2 This expresses the same meaning as above. X A X represents a crosslinking group selected from group A of crosslinking groups. A If multiple instances exist, they may be identical or different. A The preferred range is the same as the preferred range of crosslinking groups selected from group A of crosslinking groups in the polymer compound of the second layer.

[0209] [ka]

[0210] [ka]

[0211] [ka]

[0212] [ka]

[0213] [ka]

[0214] • Other constituent units The polymer compound of the second layer is preferably a polymer compound (hereinafter also referred to as "polymer compound (2')") that includes 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 driving voltage of the light-emitting element of this embodiment becomes lower. The polymer compound (2') is a polymer compound that includes 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 includes a structural unit having at least one crosslinking group selected from crosslinking group A. The polymer compound (2') is preferably a polymer compound comprising at least one constituent unit selected from the group consisting of constituent units represented by formula (X) and constituent units represented by formula (Y), and a constituent unit having at least one crosslinking group selected from crosslinking group A, since this results in a lower driving voltage for the light-emitting element of this embodiment. In polymer compound (2'), it is preferable that the structural unit having at least one crosslinking group selected from group A is different from the structural unit represented by formula (X) and the structural unit represented by formula (Y). The polymer compound (2') preferably contains the constituent unit represented by formula (Y) because it lowers the driving voltage of the light-emitting element in 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 the driving voltage of the light-emitting element of this embodiment is lower.

[0215] [ka]

[0216] [In the formula, aX1 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 to form 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.

[0217] [ka]

[0218] [In the formula, Ar Y1This 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.

[0219] 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%, because the hole transport properties of the polymer compound (2') are excellent and the driving voltage of the light-emitting element of this embodiment is lower. The constituent unit represented by formula (X) may be present in the polymer compound (2') as one type or as two or more types.

[0220] 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%, and is 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%, as this results in a lower driving voltage for the light-emitting element in 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.

[0221] • 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.

[0222] Ar Y1 The divalent heterocyclic group represented by is preferably a monocyclic or bicyclic to hexacyclic heterocyclic group from which two hydrogen atoms directly bonded to the ring-constituting atoms have been removed, as this lowers the driving voltage of the light-emitting element of this embodiment. More preferably, it is a monocyclic, bicyclic, or tricyclic heterocyclic group from which two hydrogen atoms directly bonded to the ring-constituting atoms have been removed. Even more preferably, it is a group from pyridine, diazabenzene, triazine, azananaphthalene, diazananaphthalene, carbazole, dibenzofuran, dibenzothiophene, phenoxazine, phenothiazine, 9,10-dihydroacridine, or 5,10-dihydrophenazine from which two hydrogen atoms directly bonded to the ring-constituting atoms (preferably carbon atoms or nitrogen atoms, more preferably carbon atoms) have been removed. Particularly preferably, it is a group from pyridine, diazabenzene, triazine, carbazole, dibenzofuran, dibenzothiophene, phenoxazine, or phenothiazine, These are groups consisting of two hydrogen atoms that are not directly bonded to the atoms constituting the ring (preferably carbon atoms or nitrogen atoms, more preferably carbon atoms), and these groups may have substituents.

[0223] Ar Y1In 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 Y1 This is the same as the preferred range for the arylene group and the divalent heterocyclic group represented by .

[0224] 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.

[0225] [ka]

[0226] Ar Y1 Since the driving voltage of the light-emitting element in this embodiment is lower, it is preferable that the arylene group may have substituents.

[0227] 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.

[0228] 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.

[0229] Ar Y1 The monovalent heterocyclic group in the substituent that the group represented by may have is preferably a monocyclic or bicyclic to hexacyclic group from which one hydrogen atom directly bonded to the atoms constituting the ring has been removed, since the driving voltage of the light-emitting element of this embodiment becomes lower, more preferably a monocyclic, bicyclic to hexacyclic group from which one hydrogen atom directly bonded to the atoms constituting the ring has been removed, and even more preferably pyridine, diazabenzene, triazine, azananaphthalene, diazananaphthalene, carbazole, dibenzofuran, dibenzothiophene, f The group is obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from phenoxazine, phenothiazine, 9,10-dihydroacridine, or 5,10-dihydrophenazine, and is particularly preferred to be obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from pyridine, diazabenzene, triazine, carbazole, dibenzofuran, dibenzothiophene, phenoxazine, or phenothiazine, and these may further have substituents.

[0230] 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.

[0231] 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.

[0232] The component unit represented by formula (Y) is preferably the component unit represented by formula (Y-1) or formula (Y-2) because it results in a lower driving voltage for the light-emitting element in this embodiment.

[0233] [ka]

[0234] [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.

[0235] 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.

[0236] In equation (Y-1), R Y1 at least one of (preferably R) Y1At least two of these are preferably alkyl groups, cycloalkyl groups, alkoxy groups, cycloalkoxy groups, aryl groups, aryloxy groups, monovalent heterocyclic groups, substituted amino groups, or fluorine atoms, as this lowers the driving voltage of the light-emitting element in 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.

[0237] R Y2 The driving voltage of the light-emitting element in this embodiment is lower, so preferably the group is 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.

[0238] X Y1 This is preferable because the driving voltage of the light-emitting element in this embodiment becomes lower, so -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-.

[0239] 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.

[0240] [ka]

[0241] [ka]

[0242] [ka]

[0243] [ka]

[0244] • Constituent units represented by formula (X) a X1 and a X2 This is usually an integer from 0 to 10, and since the driving voltage of the light-emitting element in this embodiment is lower, it 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.

[0245] 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.

[0246] 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.

[0247] Ar X1 ~Ar X4 and R X1 ~R X3 Examples of substituents that the group represented by may have The preferred range is Ar Y1 The examples and preferred ranges of substituents that the group represented by may have are the same.

[0248] The constituent units represented by equation (X) include the constituent units represented by the following equation. Note that in the equation, Z 2 This expresses the same meaning as above.

[0249] [ka]

[0250] [ka]

[0251] [ka]

[0252] [ka]

[0253] Examples of polymer compounds for the second layer include polymer compounds P-1 to P-11 shown in Table 1. Here, "others" refers to constituent units other than those represented by formula (Z), formula (Z'), formula (X), and formula (Y).

[0254] [Table 1]

[0255] The polymer compound of the second layer preferably does not have vinyl groups, more preferably does not have alkenyl groups, and even more preferably does not have alkenyl groups and cycloalkenyl groups. The polymer compound of the second layer 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 in the second layer, 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 in the second layer, 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.

[0256] • Method for producing the polymer compound of the second layer The polymer compound of the second layer 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, the methods for introducing the monomers include introducing the entire amount of monomers into the reaction system at once, or introducing a portion of the monomers and reacting them, then introducing the remaining monomers all at once, continuously, or in separate batches. Methods include preparing the material by adding it in a continuous or divided manner, and preparing the monomer in a continuous or divided manner. 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.

[0257] [Second composition] The second layer may contain a composition (hereinafter also referred to as "the second composition") comprising a crosslinked polymer compound of the second layer 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 polymer compound of the second layer. The second composition may contain, individually or in combination of, a crosslinked polymer compound of the second layer, 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.

[0258] In the second composition, the total content of the crosslinked polymer compound of the second layer, 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 second composition to function. In the second composition, the total content of the crosslinked polymer compound of the second layer, 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 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, based on 100 parts by mass of the crosslinked polymer compound in the second layer. In the second composition, the content of antioxidant is typically 0.00001 to 10 parts by mass, based on 100 parts by mass of the crosslinked polymer compound in the second layer.

[0259] (Second ink) The second layer can be formed, for example, using a composition (hereinafter also referred to as "second ink") containing the polymer compound of the second layer and a solvent. The second ink may contain one polymer compound and one solvent from the second layer, or two or more of each. 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 typically 1,000 to 1,000,000 parts by mass, assuming that the polymer compound content of the second layer is 100 parts by mass.

[0260] The second ink is a hole transport material, a hole injection material, an electron transport material, an electron injection material, and a light-emitting material. It may further contain at least one selected from the group consisting of fertilizers 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 polymer compound in the second layer. 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 polymer compound in the second layer.

[0261] <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.

[0262] 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.

[0263] The first layer and the second layer are preferably adjacent to each other, as this results in a lower driving voltage for the light-emitting element in this embodiment. The second layer is preferably a layer provided between the anode and the first layer, since the driving voltage of the light-emitting element in this embodiment becomes lower; 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.

[0264] If the second layer is a second light-emitting layer provided between the anode and the first layer, the driving voltage of the light-emitting element of this embodiment becomes lower, 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 driving voltage of the light-emitting element of this embodiment becomes lower, 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.

[0265] If the second layer is a second light-emitting layer provided between the cathode and the first layer, the driving voltage of the light-emitting element of this embodiment becomes lower, 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 driving voltage of the light-emitting element of this embodiment becomes lower, 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.

[0266] If the second layer is a hole transport layer provided between the anode and the first layer, the driving voltage of the light-emitting element of this embodiment becomes lower, so it is preferable to further have a hole injection layer between the anode and the second layer. Also, if the second layer is a hole transport layer provided between the anode and the first layer, the driving voltage of the light-emitting element of this embodiment becomes lower, 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.

[0267] If the second layer is a hole injection layer provided between the anode and the first layer, the driving voltage of the light-emitting element of this embodiment becomes lower, 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 driving voltage of the light-emitting element of this embodiment becomes lower, so it is preferable to further have at least one of the electron injection layer and electron transport layer between the cathode and the first layer.

[0268] If the second layer is an electron transport layer provided between the cathode and the first layer, the driving voltage of the light-emitting element of this embodiment becomes lower, 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 driving voltage of the light-emitting element of this embodiment becomes lower, so it is preferable to further have an electron injection layer between the cathode and the second layer.

[0269] 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.

[0270] (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

[0271] 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.

[0272] 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.

[0273] [First light-emitting layer] The first light-emitting layer is typically the first layer.

[0274] [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.

[0275] [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.

[0276] [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.

[0277] [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.

[0278] [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.

[0279] [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.

[0280] 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.

[0281] 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.

[0282] 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.

[0283] Methods for forming the anode and cathode include, for example, vacuum deposition, sputtering, ion plating, plating, and lamination.

[0284] [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 methods for forming the first layer, the second layer, and layers other than the first and second layers include a dry method such as vacuum deposition and a wet method as described in the section on the first ink, and when using a high-molecular-weight compound, examples of a wet method as described in the section on the first ink. 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 may be formed using the various inks and inks containing the various materials described above by a wet method as described in the section on the first ink, or by a dry method such as vacuum deposition.

[0285] 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.

[0286] 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. In other words, it is preferable to form the second layer by a wet process using the second ink.

[0287] In the method for manufacturing a light-emitting element of this embodiment, a layer containing a crosslinked polymer compound of the second layer (for example, the second layer) can be formed, for example, by heating or irradiating with light (preferably heating) after forming the layer containing the polymer compound of the second layer, thereby crosslinking the polymer compound of the second layer contained in the layer. When the polymer compound of the second layer is in a crosslinked state (crosslinked polymer compound of the second layer) and is contained in the second layer, the layer is substantially insoluble in the solvent. Therefore, a layer containing a crosslinked polymer compound of the second layer can be suitably used for lamination in the manufacturing of a light-emitting element of this embodiment.

[0288] From the above viewpoint, in the method for manufacturing a light-emitting element of this embodiment, the step of forming the second layer preferably includes a step of forming a layer containing the polymer compound of the second layer, and then crosslinking the polymer compound of the second layer contained in the layer to form a second layer containing a crosslinked polymer compound of the second layer. In the step of forming the second layer, as a method for crosslinking the polymer compound of the second layer, 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.

[0289] 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.

[0290] One step in forming the second layer is, for example, to form a layer using a wet method with a second ink, and then to crosslink the polymer compounds of the second layer contained in the layer to form the second layer.

[0291] 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.

[0292] 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.

[0293] 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.

[0294] [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).

[0295] Although preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. [Examples]

[0296] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0297] In the examples, the molecular weight of the compounds was calculated using the Molecular Weight value from ChemDraw Professional 22.2 (Revvity Signals Software).

[0298] 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.

[0299] <Synthesis Example 1> Synthesis of Compounds M1-M9 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. 2010-189630. Compound M8 was synthesized according to the method described in International Publication No. 2011 / 049241. Compound M9 was synthesized according to the method described in Japanese Patent Publication No. 2010-215886.

[0300] [ka]

[0301] <Synthesis Example 2> Synthesis of polymer compounds HTL-1 to HTL-3, HTL-C1 and HTL-C2 The polymer compounds (copolymers) HTL-1 to HTL-3, HTL-C1, and HTL-C2 were synthesized using the types and molar ratios of compounds listed in Table 2, and the synthesis methods described in the same table. The Mn and Mw of the obtained polymer compounds are as shown in Table 2.

[0302] [Table 2]

[0303] <Synthesis Example 3> Synthesis and acquisition of phosphorescent compounds E1 and E2 The phosphorescent compound E1 used was manufactured by Luminescence Technology. The phosphorescent compound E2 was synthesized according to the method described in International Publication No. 2009 / 131255.

[0304] [ka]

[0305] <Synthesis Example 4> Obtaining Compounds T1-T13 Compounds T1-T12 were sourced from Luminescence Technology. Compound T13 was manufactured by Amadis Chemical.

[0306] [ka]

[0307] [ka]

[0308] <Example D1> Fabrication and evaluation of light-emitting element D1 (Formation of anode and hole injection layer) The anode is formed by depositing an ITO film with a thickness of 45 nm onto a glass substrate using the sputtering method. The hole injection layer was formed on the anode by spin coating a 65 nm thick layer of ND-3202 (manufactured by Nissan Chemical Corporation), a hole injection material, and then heated on a hot plate at 240°C for 15 minutes in an atmospheric environment.

[0309] (Formation of the second layer) The polymer compound HTL-1 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-1 to become a crosslinked material.

[0310] (Formation of the first layer) Compound T1, compound T2, and phosphorescent compound E1 (compound T1 / compound T2 / phosphorescent compound E1 = 45% by mass / 45% by mass / 10% by mass) were dissolved in chlorobenzene to a total concentration of 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.

[0311] (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.

[0312] (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 30 mA / cm². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0313] <Examples D2-D4, Comparative Examples CD1 and CD2> Fabrication and Evaluation of Light-Emitting Devices D2-D4, CD1 and CD2 Except for using the materials and material ratios listed in Table 3 in Example D1 (formation of the first layer), light-emitting elements D2-D4, CD1, 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 D2-D4, CD1, and CD2. The current density of light-emitting elements D2-D4, CD1, and CD2 was 30 mA / cm². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0314] The results for Examples D1 to D4 and Comparative Examples CD1 and CD2 are shown in Table 3. In Table 3, the drive voltage difference [V] refers to the difference in drive voltage [V] of light-emitting elements D1 to D4 and CD2 relative to the drive voltage [V] of light-emitting element CD1.

[0315] [Table 3]

[0316] <Example D5 and Comparative Example CD3> Fabrication and Evaluation of Light-Emitting Devices D5 and CD3 Except for using the materials and material ratios listed in Table 4 in Example D1 (formation of the first layer), light-emitting elements D5 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 and CD3. The current density of light-emitting elements D5 and CD3 was 50 mA / cm². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0317] The results for Example D5 and Comparative Example CD3 are shown in Table 4. In Table 4, the drive voltage difference [V] refers to the difference between the drive voltage [V] of the light-emitting element D5 and the drive voltage [V] of the light-emitting element CD3.

[0318] [Table 4]

[0319] <Example D6 and Comparative Example CD4> Fabrication and Evaluation of Light-Emitting Devices D6 and CD4 Except for using the materials and material ratios listed in Table 5 in Example D1 (formation of the first layer), light-emitting elements D6 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 D6 and CD4. The current density of light-emitting elements D6 and CD4 was 50 mA / cm². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0320] The results for Example D6 and Comparative Example CD4 are shown in Table 5. In Table 5, the drive voltage difference [V] refers to the difference between the drive voltage [V] of the light-emitting element D6 and the drive voltage [V] of the light-emitting element CD4.

[0321] [Table 5]

[0322] <Example D7 and Comparative Example CD5> Fabrication and Evaluation of Light-Emitting Devices D7 and CD5 Except for using the materials and material ratios listed in Table 6 in Example D1 (formation of the first layer), light-emitting elements D7 and CD5 were fabricated in the same manner as in Example D1. EL emission was observed when a voltage was applied to light-emitting elements D7 and CD5. The current density of light-emitting elements D7 and CD5 was 100 mA / cm². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0323] The results for Example D7 and Comparative Example CD5 are shown in Table 6. In Table 6, the drive voltage difference [V] refers to the difference between the drive voltage [V] of the light-emitting element D7 and the drive voltage [V] of the light-emitting element CD5.

[0324] [Table 6]

[0325] <Example D8 and Comparative Example CD6> Fabrication and Evaluation of Light-Emitting Devices D8 and CD6 Except for using the materials and material ratios listed in Table 7 in Example D1 (formation of the first layer), light-emitting elements D8 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 D8 and CD6. The current density of light-emitting elements D8 and CD6 was 75 mA / cm². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0326] The results for Example D8 and Comparative Example CD6 are shown in Table 7. In Table 7, the drive voltage difference [V] refers to the difference between the drive voltage [V] of the light-emitting element D8 and the drive voltage [V] of the light-emitting element CD6.

[0327] [Table 7]

[0328] <Example D9 and Comparative Example CD7> Fabrication and Evaluation of Light-Emitting Devices D9 and CD7 Except for using the materials and material ratios listed in Table 8 in Example D1 (formation of the first layer), light-emitting elements D9 and CD7 were fabricated in the same manner as in Example D1. EL emission was observed when a voltage was applied to light-emitting elements D9 and CD7. The current density of light-emitting elements D9 and CD7 was 100 mA / cm². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0329] The results for Example D9 and Comparative Example CD7 are shown in Table 8. In Table 8, the drive voltage difference [V] refers to the difference between the drive voltage [V] of the light-emitting element D9 and the drive voltage [V] of the light-emitting element CD7.

[0330] [Table 8]

[0331] <Example D10 and Comparative Example CD8> Fabrication and Evaluation of Light-Emitting Devices D10 and CD8 Except for using the materials and material ratios listed in Table 9 in Example D1 (formation of the first layer), light-emitting elements D10 and CD8 were fabricated in the same manner as in Example D1. EL emission was observed when a voltage was applied to light-emitting elements D10 and CD8. The current density of light-emitting elements D10 and CD8 was 100 mA / cm². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0332] The results for Example D10 and Comparative Example CD8 are shown in Table 9. In Table 9, the drive voltage difference [V] refers to the difference between the drive voltage [V] of the light-emitting element D10 and the drive voltage [V] of the light-emitting element CD8.

[0333] [Table 9]

[0334] <Examples D11-D13> Fabrication and evaluation of light-emitting elements D11-D13 Except for using the materials and material ratios listed in Table 10 in Example D1 (formation of the first layer), light-emitting elements D11 to D13 were fabricated in the same manner as in Example D1. EL emission was observed when a voltage was applied to light-emitting elements D11 to D13. The current density of light-emitting elements D11 to D13 was 0.5 mA / cm². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0335] The results for Examples D11 to D13 are shown in Table 10. In Table 10, the drive voltage difference [V] refers to the difference in drive voltage [V] of light-emitting elements D11 and D12 relative to the drive voltage [V] of light-emitting element D13.

[0336] [Table 10]

[0337] <Examples D14, D15 and Comparative Example CD9> Fabrication and Evaluation of Light-Emitting Devices D14, D15 and CD9 Except for using the materials and material ratios listed in Table 11 in the (formation of the second layer) and (formation of the first layer) of Example D1, light-emitting elements D14, D15, and CD9 were fabricated in the same manner as in Example D1. EL emission was observed when a voltage was applied to the light-emitting elements D14, D15, and CD9. The current density of the light-emitting elements D14, D15, and CD9 was 0.01 mA / cm². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0338] The results for Examples D14, D15 and Comparative Example CD9 are shown in Table 11. In Table 11, the drive voltage difference [V] refers to the difference in drive voltage [V] of light-emitting elements D14 and D15 relative to the drive voltage [V] of light-emitting element CD9.

[0339] [Table 11]

[0340] <Example D16, Comparative Examples CD10 and CD11> Fabrication and Evaluation of Light-Emitting Devices D16, CD10 and CD11 Except for using the materials and material ratios listed in Table 12 in the (formation of the second layer) and (formation of the first layer) of Example D1, light-emitting elements D16, CD10, 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 D16, CD10, and CD11. The current density of light-emitting elements D16, CD10, and CD11 was 0.015 mA / cm². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0341] The results for Example D16 and Comparative Examples CD10 and CD11 are shown in Table 12. In Table 12, the drive voltage difference [V] refers to the difference in drive voltage [V] of light-emitting elements D16 and CD10 relative to the drive voltage [V] of light-emitting element CD11.

[0342] [Table 12]

[0343] <Example D17 and Comparative Example CD12> Fabrication and Evaluation of Light-Emitting Devices D17 and CD12 Except for using the materials and material ratios listed in Table 13 in Example D1 (formation of the second layer) and (formation of the first layer), the light-emitting elements D17 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 D17 and CD12. The current density of the light-emitting elements D17 and CD12 was 100 mA / cm². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0344] The results for Example D17 and Comparative Example CD12 are shown in Table 13. In Table 13, the drive voltage difference [V] refers to the difference between the drive voltage [V] of the light-emitting element D17 and the drive voltage [V] of the light-emitting element CD12.

[0345] [Table 13]

[0346] <Example D18 and Comparative Example CD13> Fabrication and Evaluation of Light-Emitting Devices D18 and CD13 Except for using the materials and material ratios listed in Table 14 in the (formation of the second layer) and (formation of the first layer) of Example D1, the light-emitting elements D18 and CD13 were fabricated in the same manner as in Example D1. EL emission was observed when a voltage was applied to the light-emitting elements D18 and CD13. The current density of the light-emitting elements D18 and CD13 was 75 mA / cm². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0347] The results for Example D18 and Comparative Example CD13 are shown in Table 14. In Table 14, the drive voltage difference [V] refers to the difference between the drive voltage [V] of the light-emitting element D18 and the drive voltage [V] of the light-emitting element CD13.

[0348] [Table 14]

[0349] In each of the above examples and comparative examples, compounds T1 to T13 were used as host materials. Furthermore, in each of the above examples and comparative examples, phosphorescent compounds E1 and E2 were used as guest materials.

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 phosphorescent compound and two or more compounds represented by formula (T-1), The second layer is a layer containing a crosslinked polymer compound which includes a structural unit having at least one crosslinking group selected from group A of crosslinking groups, Of the two or more compounds represented by formula (T-1) mentioned above, Ar in at least two of the compounds Ｔ２ However, if each of the two compounds is independently a monocyclic and six-membered heterocyclic ring containing a group represented by =N- within the ring, and one or more hydrogen atoms have been removed from it, then the light-emitting element comprises two compounds that satisfy at least one requirement selected from the group consisting of requirement (i) and requirement (ii). (i) The difference in the number of nitrogen atoms constituting the monocyclic and six-membered heterocyclic ring containing a group represented by =N- within the ring is 2 or more. (ii) The difference in molecular weight is 80 or more. 【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 A monovalent heterocyclic group that does not contain a group represented by -, and the monovalent heterocyclic group 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 is bonded. L Ｔ１ represents a divalent group, which may have substituents. When there are a plurality of the substituents, they may be the same or different, and may combine with each other to form a ring together with the atoms to which they are respectively attached. L Ｔ１ When there are a plurality of Ls, they may be the same or different, and they may combine with each other directly or via a divalent group to form a ring. Ar Ｔ２ These are groups represented by -C(=O)-, -S(=O)-, and -S(=O) ２ A group represented by -, 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 A heterocyclic group comprising at least one group selected from the group consisting of groups represented by -, where 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. 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 is 2 That is the case. Ar Ｔ１ and L Ｔ１ Ar may form a ring by directly bonding with or by bonding via a divalent group. Ｔ２ and L Ｔ１ Ar may form a ring by directly bonding with or by bonding via a divalent group. Ｔ１ and Ar Ｔ２ It may form a ring by directly bonding with or via a divalent group. 【Chemistry 2】 [In the formula, R ＸＬ n represents a methylene group, an oxygen atom, or a sulfur atom. ＸＬ This represents an integer between 0 and 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.

2. The Ar Ｔ１ At least one of the rings contains a nitrogen atom that does not form a double bond within the ring, and the ring contains a group represented as =N-, a group represented as -C(=O)-, a group represented as -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. Among the two or more compounds represented by formula (T-1) mentioned above, Ar in at least one compound Ｔ２ The light-emitting element according to claim 4, wherein the heterocyclic group contains a group represented by =N- within the ring, and the group may have substituents.

6. The light-emitting element according to claim 1, wherein the phosphorescent compound is a metal complex represented by formula (1). 【Transformation 3】 [In the formula, M represents a rhodium atom, palladium atom, iridium atom, or platinum atom. n １ represents an integer greater than or equal to 1, and n ２ n represents a non-negative integer. However, if M is a rhodium atom or an iridium atom, n represents a non-negative integer. １ +n ２ is 3, and when M is a palladium atom or a platinum atom, n １ +n ２ The answer is 2. E １ and E ２ Each of these independently represents a carbon atom or a nitrogen atom. １ and E ２ If multiple instances exist, they may be identical or different from one another. Ring L １ represents an aromatic heterocycle, which may have substituents. If there are multiple substituents, they may be the same or different, and may be bonded to each other, forming a ring with the atom to which each substituent is bonded. Ring L １ If multiple instances exist, they may be identical or different. Ring L ２ represents an aromatic hydrocarbon ring or an aromatic heterocycle, and these rings 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. Ring L ２ If multiple instances exist, they may be identical or different. Ring L １ A substituent that may be present in ring L ２ The substituents that may be present may be the same or different, and may be bonded to each other, forming a ring with the atom to which each is bonded. A １ -G １ -A ２ This represents an anionic bidentate ligand. １ and A ２ Each of these independently represents a carbon atom, an oxygen atom, or a nitrogen atom, and these atoms may be atoms that constitute a ring. １ is a single bond, or A １ and A ２ It represents the group of atoms that together constitute a bidentate ligand. A １ -G １ -A ２ If multiple instances exist, they may be identical or different.

7. The aforementioned ring L １ However, the ring L is a pyridine ring, a diazabenzene ring, an azanaphthalene ring, a diazanaphthalene ring, a diazole ring, or a triazole ring, and these rings may have substituents, and the ring L ２ The light-emitting element according to claim 6, wherein the element is a benzene ring, a pyridine ring, or a diazabenzene ring, and these rings may have substituents.

8. The light-emitting element according to claim 1, wherein a constituent unit having at least one crosslinking group selected from the crosslinking group A is a constituent unit represented by formula (Z) or a constituent unit represented by formula (Z'). 【Chemistry 4】 [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 crosslinking group selected from the aforementioned crosslinking group A. If there are multiple Xs, they may be the same or different. 【Transformation 5】 [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. They may be in that state, or they may be bonded to each other, forming a ring with the atom they bond to. K 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. K Ａ If multiple instances exist, they may be identical or different. X' represents a hydrogen atom, a bridging group selected from the bridging group A, 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. However, at least one X' is a bridging group selected from the bridging group A.

9. The light-emitting element according to claim 8, wherein at least one of the crosslinking groups selected from the group A is a group represented by formula (XL-1), formula (XL-16), or formula (XL-17).

10. The light-emitting element according to claim 1, 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.

11. The light-emitting element according to claim 1, wherein the first layer and the second layer are adjacent to each other.

12. The light-emitting element according to claim 1, wherein the second layer is a layer provided between the anode and the first layer.

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