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 is a layer containing compound (B) and two or more compounds represented by formula (T-1), and compound (B) is a boron atom, an oxygen atom, a sulfur atom, a selenium atom, sp 3 A compound having a fused heterocyclic skeleton (b) containing at least one selected from the group consisting of carbon atoms and nitrogen atoms in the ring, wherein the second layer is a layer containing a crosslinked compound having a crosslinking group, and of the two or more compounds represented by formula (T-1), at least two compounds contain Ar T2 However, if each is independently a group obtained by removing one or more hydrogen atoms from a pyrimidine, then the at least two compounds are (i) light-emitting elements having a molecular weight difference of 80 or more. TIFF2026053954000076.tif20170

Description

[Technical Field]

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

[0002] Organic electroluminescent elements (hereinafter also referred to as "light-emitting elements") can be suitably used in display and lighting applications, and research and development are underway. For example, Patent Document 1 describes a light-emitting device having a light-emitting layer containing at least one host compound, at least one thermally activated delayed phosphor, and at least one compound having a boron atom.

[0003] Furthermore, Patent Document 2 describes a light-emitting element having a light-emitting layer containing a polycyclic heterocyclic compound and a specific compound. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2020 / 040298 [Patent Document 2] International Publication No. 2022 / 138790 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] 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]

[0006] 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 compound (B) and two or more compounds represented by formula (T-1), The compound (B) contains a boron atom, an oxygen atom, a sulfur atom, a selenium atom, and sp 3 A compound having a fused heterocyclic skeleton (b) containing at least one atom selected from the group consisting of carbon atoms and nitrogen atoms within the ring, The second layer is a layer containing a crosslinked compound having a crosslinking group, 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 group obtained by removing one or more hydrogen atoms from a pyrimidine, then the light-emitting element comprises two compounds that satisfy requirement (i). (i) 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. It's fine if you do that. Ar T1 represents a substituted amino group or a monovalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other, forming a ring with the atom to which each substituent is bonded. T1 If multiple elements exist, they may be identical or different, and they may be directly bonded to each other or bonded via divalent groups to form a ring. However, Ar T1 A monovalent heterocyclic group in this context is a monovalent heterocyclic group that contains a nitrogen atom that does not form a double bond within the ring, and does not contain any groups represented by =N-, -C(=O)-, -S(=O)-, or -S(=O)2- within the ring. L T1represents a divalent group, which may have substituents. When there are a plurality of the substituents, they may be the same or different, and may be bonded to each other to form a ring together with the atoms to which they are respectively bonded. L T1 When there are a plurality of T1 , they may be the same or different, and they may be bonded to 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 be bonded to each other to form a ring together with the atoms to which they are respectively bonded. However, Ar T2 The heterocyclic group containing a group represented by =N- in the ring of Ar is a polycyclic heterocyclic group containing a group represented by =N- in the ring or a monocyclic 6-membered heterocyclic group containing a group represented by =N- in the ring. 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. [2] Said Ar T1The light-emitting element according to [1], wherein at least one of the elements is a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from a polycyclic heterocyclic compound that contains a nitrogen atom that does not form a double bond in the ring and does not contain a group represented by =N-, a group represented by -C(=O)-, a group represented by -S(=O)-, and a group represented by -S(=O)2- in the ring, and the element may have substituents. [3] The light-emitting element according to [2], wherein the polycyclic heterocyclic compound is a tricyclic, tetracyclic, pentacyclic, or hexacyclic heterocyclic compound. [4] The aforementioned Ar T2 The light-emitting element is a group represented by -C(=O)-, a group represented by -S(=O)2-, an aromatic hydrocarbon group having an electron-withdrawing group, or a heterocyclic group containing in the ring at least one group selected from the group consisting of a group represented by =N-, a group represented by -C(=O)-, and a group represented by -S(=O)2-, and these groups may have substituents, as described in any of [1] to [3]. [5] Of 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 any one of [1] to [4], wherein the heterocyclic group contains a group represented by =N- within the ring, and these groups may have substituents. [6] The light-emitting element according to any one of [1] to [5], wherein the condensed heterocyclic skeleton (b) contains a boron atom and at least one atom selected from the group consisting of an oxygen atom, a sulfur atom, and a nitrogen atom within the ring. [7] The light-emitting element according to any one of [1] to [6], wherein the compound (B) is a compound represented by formula (1-1), a compound represented by formula (1-2), or a compound represented by formula (1-3). [ka] [In the formula, Ar 1 Ar 2 and Ar 3Each of these independently represents an aromatic hydrocarbon group or a 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. Y 1 represents an oxygen atom, a sulfur atom, a selenium atom, a group represented by -N(Ry)-, an alkylene group, or a cycloalkylene 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. Y 2 and Y 3 Each of these independently represents a single bond, an oxygen atom, a sulfur atom, a selenium atom, a group represented by -N(Ry)-, a group represented by -B(Ry)-, an alkylene group, a cycloalkylene group, an arylene group, or a divalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may bond to each other to form a ring with the atom to which they are bonded. Ry 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. If there are multiple Ry groups, they may be the same or different. Y 1 and Ar 1 This may involve direct bonding or bonding via a divalent group to form a ring. 1 and Ar 2 This may involve direct bonding or bonding via a divalent group to form a ring. 2 and Ar 1 This may involve direct bonding or bonding via a divalent group to form a ring. 2 and Ar 3 This may involve direct bonding or bonding via a divalent group to form a ring. 3 and Ar 2This may involve direct bonding or bonding via a divalent group to form a ring. 3 and Ar 3 This may involve direct bonding or bonding via a divalent group to form a ring. [8] The aforementioned Y 1 , the aforementioned Y 2 and Y 3 The light-emitting element according to [7], wherein each is independently represented by an oxygen atom, a sulfur atom, or a -N(Ry)- group. [9] The compound having the crosslinking group is a polymer compound containing a structural unit represented by formula (Z) and / or a structural unit represented by formula (Z'), or a compound represented by formula (Z''), A light-emitting element as described in any of [1] to [8]. [ka] [In the formula, n represents an integer greater than or equal to 1. nA represents a non-negative integer. If there are multiple nA values, they may be the same or different. Ar Z represents a hydrocarbon group, a heterocyclic group, or a group in which at least one hydrocarbon group and at least one heterocyclic group are directly bonded, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which each substituent is bonded. L AR' represents an alkylene group, a cycloalkylene group, an arylene group, a divalent heterocyclic group, a group represented by -N(R')-, an oxygen atom, or a sulfur atom, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which they are bonded. R' represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which they are bonded. A If multiple instances exist, they may be identical or different. X represents a crosslinking group. If there are multiple X's, they may be the same or different. [ka] [In the formula, mA, m, and c each independently represent a non-negative integer. If there are multiple mA values, they may be the same or different. If there are multiple m values, they may be the same or different. Ar 5 represents a hydrocarbon group, a heterocyclic group, or a group in which at least one hydrocarbon group and at least one heterocyclic group are directly bonded, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which each is bonded. 5 If multiple instances exist, they may be identical or different. Ar 4 and Ar 6 Each of these independently represents an arylene group or a divalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which they are bonded. K AR'' represents an alkylene group, a cycloalkylene group, an arylene group, a divalent heterocyclic group, a group represented by -N(R'')-, an oxygen atom, or a sulfur atom, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which they are bonded. R'' represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which they are bonded. K A If multiple instances exist, they may be identical or different. X' represents a hydrogen atom, a bridging group, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which each substituent is bonded. If there are multiple X's, they may be the same or different, provided that at least one X' is a bridging group. [ka] [In the formula, m B1 , m B2 and m B3 Each of these independently represents a non-negative integer. There are multiple m B1 They may be the same or different. B3 If multiple instances exist, they may be identical or different. Ar 7 represents a hydrocarbon group, a heterocyclic group, or a group in which at least one hydrocarbon group and at least one heterocyclic group are directly bonded, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which each is bonded. 7 If multiple instances exist, they may be identical or different. L B1R''' represents an alkylene group, a cycloalkylene group, an arylene group, a divalent heterocyclic group, a group represented by -N(R''')-, an oxygen atom, or a sulfur atom, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which they are bonded. R''' represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which they are bonded. B1 If there are multiple X''s, they may be the same or different. X'' represents a bridging group, a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other, forming a ring with the atom to which each is bonded. Multiple X''s may be the same or different. However, if there are multiple X''s Of the X'', at least one is a crosslinking group.

[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

[11] , 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]

[0007] 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]

[0008] Preferred embodiments of the present invention will be described in detail below.

[0009] <Explanation of common terms> Terms used in this specification, unless otherwise specified, have the following meanings:

[0010] 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.

[0011] "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.

[0012] "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.

[0013] 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.

[0014] 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.

[0015] Alkyl groups may have substituents. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, 2-butyl, isobutyl, tert-butyl, pentyl, isoamyl, 2-ethylbutyl, hexyl, heptyl, octyl, 2-ethylhexyl, 3-propylheptyl, decyl, 3,7-dimethyloctyl, 2-ethyloctyl, 2-hexyldecyl, and dodecyl groups. In addition, alkyl groups may be groups in which some or all of the hydrogen atoms in these groups are substituted with substituents (for example, trifluoromethyl, pentafluoroethyl, perfluorobutyl, perfluorohexyl, perfluorooctyl, 3-phenylpropyl, 3-(4-methylphenyl)propyl, 3-(3,5-di-hexylphenyl)propyl, and 6-ethyloxyhexyl groups).

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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."

[0027] 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.

[0028] The number of carbon atoms in the heterocyclic group, excluding the number of carbon atoms in substituents, is usually 1 to 60, preferably 2 to 40, and more preferably 3 to 20. The number of heteroatoms in the heterocyclic group is Excluding the number of heteroatoms of substituents, the number is typically 1 to 30, preferably 1 to 10, more preferably 1 to 5, and even more preferably 1 to 3.

[0029] Examples of heterocyclic groups include monocyclic heterocyclic compounds (e.g., furan, thiophene, oxadiazole, thiadiazole, pyrrole, diazole, triazole, tetrazole, pyridine, diazabenzene, and triazine) or polycyclic heterocyclic compounds (e.g., azanaphthalene, diazanaphthalene, benzofuran, benzothiophene, indole, azaindole, diazindole, benzodiazole, benzothiadiazole, benzotriazole, benzothiophene) Bicyclic heterocyclic compounds such as dioxides, benzothiophene oxide, and benzopyranone; dibenzofuran, dibenzothiophene, dibenzothiophene dioxide, dibenzothiophene oxide, dibenzopyranone, dibenzobolol, dibenzosilol, dibenzophosphole, dibenzoselenophene, carbazole, azacarbazole, diazacarbazole, phenoxazine, phenothiazine, 9,10-dihydroacridine, 5,10-dihydrophenazine, acridone, phenazavolin, Tricyclic heterocyclic compounds such as phenophosphatine, phenoselenazine, phenazacillin, azaanthracene, diazaanthracene, azaphenanthrene, and diazaphenanthrene; tetracyclic heterocyclic compounds such as hexazatriphenylene, benzocarbazole, azabenzocarbazole, diazabenzocarbazole, benzonaphthofuran, and benzonaphthothiophene; dibenzocarbazole, indenocarbazole, indenocarbazole, azaindolocarbazole, and diazaindolocarbazole Examples include five-cyclic heterocyclic compounds such as iodine, azaindenocarbazole, and diazaindenocarbazole; six-cyclic heterocyclic compounds such as carbazolocarbazole, benzoindolocarbazole, and benzoindenocarbazole; and seven-cyclic heterocyclic compounds such as dibenzoindolocarbazole and dibenzoindenocarbazole. Examples include groups obtained by removing one or more hydrogen atoms directly bonded to the atoms constituting the ring, and groups in which some or all of the hydrogen atoms in the group are substituted with substituents. Heterocyclic groups include groups in which multiple such groups are bonded. Heterocyclic groups may have substituents.

[0030] 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.

[0031] 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.

[0032] "Halogen atom" refers to a fluorine atom, chlorine atom, bromine atom, or iodine atom.

[0033] 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 bond to each other, each to which nitrogen atoms are bonded. They may form a circle together with their children. 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] The number of carbon atoms in the "cycloalkynyl group," excluding the carbon atoms of substituents, is usually 4 to 50, preferably 5 to 20, and more preferably 6 to 10. Alkynyl groups and cycloalkynyl groups may have substituents. Examples of alkynyl groups include ethynyl, 1-propynyl, 2-propynyl, 2-butynyl, 3-butynyl, 3-pentynyl, 4-pentynyl, 1-hexynyl, 5-hexynyl, and groups in which some or all of the hydrogen atoms in these groups are substituted with substituents. Examples of cycloalkynyl groups include cyclooctinyl and groups in which some or all of the hydrogen atoms in this group are substituted with substituents.

[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 a crosslinking group selected from group A (i.e., a group represented by any of formulas (XL-1) to (XL-19)). [ka]

[0040] [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.

[0041] 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.

[0042] 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.

[0043] 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 density functional at the B3LYP level... The ground state of the compound is structurally optimized using a specific method. The basis set used is 6-31G*. Then, using the resulting optimized structure, the lowest excited singlet state (S1) and lowest excited triplet state (T1) of the compound are calculated using a B3LYP-level time-dependent density functional theory. However, if the compound contains atoms for which 6-31G* cannot be used, LANL2DZ is used for those atoms. The quantum chemical calculation program used is Gaussian.

[0044] <First layer> In the light-emitting element of this embodiment, the first layer is a layer containing compound (B) and two or more compounds represented by formula (T-1). The first layer may contain one type of compound (B) alone, or two or more types. The first layer may contain only two types of compounds represented by formula (T-1), or three or more types.

[0045] 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.

[0046] In the first layer, the total content of compound (B) 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 compound (B) 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.

[0047] In the first layer, the content of compound (B) is limited to a range that allows the first layer to function as such. In the first layer, the content of compound (B) may be, for example, 0.01 to 99 parts by mass, with the total content of compound (B) and all compounds represented by formula (T-1) in the first layer being 100 parts by mass. Preferably, it is 0.05 to 90 parts by mass, more preferably 0.1 to 70 parts by mass, even more preferably 0.2 to 50 parts by mass, particularly preferably 0.5 to 30 parts by mass, and especially preferably 1 to 10 parts by mass, as this lowers the driving voltage of the light-emitting element in this embodiment.

[0048] 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 99.99 parts by mass, with the total content of compound (B) and all compounds represented by formula (T-1) in the first layer being 100 parts by mass. Preferably, it is 10 to 99.95 parts by mass, more preferably 30 to 99.9 parts by mass, even more preferably 50 to 99.8 parts by mass, particularly preferably 70 to 99.5 parts by mass, and especially preferably 90 to 99 parts by mass, as this lowers the driving voltage of the light-emitting element in this embodiment.

[0049] 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. 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 1 to 99 parts by mass, more preferably 10 to 90 parts by mass, even more preferably 30 to 70 parts by mass, and particularly preferably 40 to 60 parts by mass, with the total content of all compounds represented by formula (T-1) in the first layer being 100 parts by mass.

[0050] In the first layer, the total content of the two most abundant compounds among the two or more compounds represented by formula (T-1) is limited to a range that allows the first layer to function as intended. In the first layer, the total content of the two most abundant compounds among the two or more compounds represented by formula (T-1) is, for example, 1 to 100 parts by mass, preferably 10 to 100 parts by mass, more preferably 30 to 100 parts by mass, even more preferably 50 to 100 parts by mass, particularly preferably 70 to 100 parts by mass, and especially preferably 90 to 100 parts by mass, with the total content of all compounds represented by formula (T-1) in the first layer being 100 parts by mass.

[0051] In the first layer, compound (B) preferably interacts physically, chemically, or electrically with the compound represented by formula (T-1). Furthermore, in the first layer, it is preferable that each of the two or more compounds represented by formula (T-1) interacts physically, chemically, or electrically. The above interactions make it possible to improve or adjust, for example, the light emission characteristics, charge transport characteristics, or charge injection characteristics of the light-emitting element of this embodiment. In the light-emitting element of this embodiment, if we explain the light-emitting material as an example, two or more compounds represented by formula (T-1) interact electrically with each other, and further, compound (B) 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 compound (B), compound (B) 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 compound (B). 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 compound (B).

[0052] The compound represented by formula (T-1) is preferably one that is soluble in a solvent capable of dissolving compound (B), since the light-emitting element of this embodiment can be fabricated by a wet process.

[0053] 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.

[0054] In the light-emitting element of this embodiment, if the first layer is a layer containing a host material and a guest material, the total content of the host material and guest material in the first layer may 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 since the driving voltage of the light-emitting element of this embodiment becomes lower, it 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. It is a percentage.

[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 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 0.05 to 90 parts by mass, more preferably 0.1 to 70 parts by mass, even more preferably 0.2 to 50 parts by mass, particularly preferably 0.5 to 30 parts by mass, and especially preferably 1 to 10 parts by mass.

[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 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, it is preferable that compound (B) in the first layer is a guest material because the driving voltage of the light-emitting element of this embodiment becomes lower.

[0057] 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.

[0058] 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.

[0059] [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).

[0060] The compound represented by formula (T-1) is a different compound from compound (B), and is, for example, a compound that does not have the fused heterocyclic skeleton (b) described later.

[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, more preferably an integer between 0 and 3, even 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 that does not contain a fused heterocyclic skeleton (b), 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 that does not contain a fused heterocyclic skeleton (b). These groups may have substituents. Examples of heterocyclic compounds that do not contain a fused heterocyclic skeleton (b) in the monovalent donor-type heterocyclic group include, among the heterocyclic compounds described in the section on heterocyclic groups above, heterocyclic compounds that do not contain boron atoms and nitrogen atoms in the ring.

[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 do 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 (preferably heterocyclic compounds that do not contain a fused heterocyclic skeleton (b)).

[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, and even more preferably 7 to 30. The value is, and is particularly preferably between 10 and 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 that does not contain a condensed heterocyclic skeleton (b), 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 that does not contain a fused heterocyclic skeleton (b), since this results in a lower driving voltage for the light-emitting element of this embodiment. Specifically, the monovalent donor-type heterocyclic group is preferably a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring (preferably a carbon atom or a nitrogen atom, more preferably a nitrogen atom) from a polycyclic heterocyclic compound (preferably a polycyclic heterocyclic compound that does not contain a fused heterocyclic skeleton (b)) that contains a nitrogen atom that does not form a double bond in the ring and does not contain a group represented by =N-, a group represented by -C(=O)-, a group represented by -S(=O)-, and a group represented by -S(=O)2- in the ring, since this results in a lower driving voltage for the light-emitting element of this embodiment. 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 (preferably a heterocyclic compound that does not contain a fused heterocyclic skeleton (b)), more preferably a polycyclic heterocyclic compound containing a 5-membered ring or a 6-membered ring (preferably a polycyclic heterocyclic compound that does not contain a fused heterocyclic skeleton (b)), even more preferably a polycyclic heterocyclic compound containing a 6-membered ring (preferably a polycyclic heterocyclic compound that does not contain a fused heterocyclic skeleton (b)), and particularly preferably a polycyclic heterocyclic compound containing both a 5-membered ring and a 6-membered ring (preferably a polycyclic heterocyclic compound that does not contain a fused heterocyclic skeleton (b)). In donor-type heterocyclic compounds, examples of heterocyclic compounds containing a 5-membered ring or a 6-membered ring include heterocyclic compounds containing a 5-membered ring or a 6-membered ring (preferably heterocyclic compounds that do not contain a fused heterocyclic skeleton (b)) among the heterocyclic compounds described in the section on heterocyclic groups above. When the donor heterocyclic compound is a polycyclic heterocyclic compound, the donor heterocyclic compound is preferably a bicyclic to heptacyclic compound that does not contain a condensed heterocyclic skeleton (b), more preferably a tricyclic to hexacyclic compound that does not contain a condensed heterocyclic skeleton (b), 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, 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. T1The 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 T1 The aryl group in the substituent that may be present is preferably a monocyclic or bicyclic to hexacyclic aromatic hydrocarbon from which one hydrogen atom directly bonded to a carbon atom constituting the ring has been removed, since this 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. Ar T1As 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 monocyclic or bicyclic to hexacyclic heterocyclic compound (preferably a monocyclic or bicyclic to hexacyclic heterocyclic compound that does not contain a fused heterocyclic skeleton (b)) from which one hydrogen atom directly bonded to the atoms constituting the ring has been removed, and more preferably a monocyclic, bicyclic or tricyclic heterocyclic compound (preferably a monocyclic, bicyclic or tricyclic heterocyclic compound that does not contain a fused heterocyclic skeleton (b)) from which one hydrogen atom directly bonded to the atoms constituting the ring A group with one hydrogen atom removed, more preferably 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, A group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from 10-dihydrophenazine, acridone, azaanthracene, diazaanthracene, azaphenanthrene, or diazaphenanthrene, and particularly preferably pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, dibenzofuran, dibenzothiophene, carbazole, azacarbazole, diazacarbazole, phenoxazine, phenothiazine, 9,10-dihydroacridine, or 5,10-dihydrophenazine, which is directly bonded to an atom constituting the ring The group is one hydrogen atom removed from the bonded atom, 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. Ar T1In the substituted amino group in the substituent that may be possessed, as the substituent of the amino group, an aryl group or a monovalent heterocyclic group is preferable, an aryl group is more preferable, and these groups may further have a substituent. Examples and preferred ranges of the aryl group in the substituent of the amino group are the same as those of Ar T1 Examples and preferred ranges of the aryl group in the substituent that may be possessed are the same as those of the aryl group in the substituent that may be possessed. Examples and preferred ranges of the monovalent heterocyclic group in the substituent of the amino group are the same as those of Ar T1 Examples and preferred ranges of the monovalent heterocyclic group in the substituent that may be possessed are the same as those of the monovalent heterocyclic group in the substituent that may be possessed.

[0071] Ar T1 As the substituent that the substituent that may be possessed by Ar 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 preferably do not 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 by Ar may further have are the same as those of the aryl group, monovalent heterocyclic group and substituted amino group in the substituent that may be possessed by Ar T1 Examples and preferred ranges of the aryl group, monovalent heterocyclic group and substituted amino group in the substituent that may be possessed are the same as those of the aryl group, monovalent heterocyclic group and substituted amino group in the substituent that may be possessed.

[0072] 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 device of the present embodiment becomes lower. Ar T1 Ar is preferably a monovalent donor-type heterocyclic group that may have a substituent because the driving voltage of the light-emitting device of the present embodiment becomes even lower.

[0073] ArT1 When there are a plurality of them, 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. However, since the synthesis of the compound represented by the formula (T-1) is easy, it is preferable not to form a ring. Ar T1 When 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, a group represented by -N(R T1 ’)-, 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 ’)-, 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. 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.

[0074] In the case of divalent groups, the divalent heterocyclic group is preferably a monocyclic or bicyclic to hexacyclic heterocyclic compound (preferably a monocyclic or bicyclic to hexacyclic heterocyclic compound that does not contain a fused heterocyclic skeleton (b)) from which two hydrogen atoms directly bonded to the ring-constituting atoms (preferably carbon atoms) have been removed. More preferably, it is a monocyclic, bicyclic, or tricyclic heterocyclic compound (preferably a monocyclic, bicyclic, or tricyclic heterocyclic compound that does not contain a fused heterocyclic skeleton (b)) from which two hydrogen atoms directly bonded to the ring-constituting atoms (preferably carbon atoms) have been removed. Even more preferably, pyridine, diazabenzene, triazine, azananaphthalene, dizananaphthalene, dibenzofuran, dibenzothiophene, or carbazole The group is obtained by removing two hydrogen atoms directly bonded to the ring-forming atoms (preferably carbon atoms) from azacarbazole, diazacarbazole, phenoxazine, phenothiazine, 9,10-dihydroacridine, or 5,10-dihydrophenazine, and is particularly preferably a group obtained by removing two hydrogen atoms directly bonded to the ring-forming atoms (preferably carbon atoms) from pyridine, diazabenzene, triazine, carbazole, phenoxazine, phenothiazine, 9,10-dihydroacridine, or 5,10-dihydrophenazine, and is especially preferably a group obtained by removing two hydrogen atoms directly bonded to the ring-forming carbon atoms from pyridine, diazabenzene, or triazine, and these groups may have substituents. Examples and preferred ranges of substituents that the divalent group may have are Ar T1 The examples and preferred ranges of substituents that may be present are the same as those mentioned above.

[0075] R T1 ' is a hydrogen atom, alkyl group, cycloalkyl group, alkoxy group, cycloalco This represents a xy group, an aryl group, an aryloxy group, a monovalent heterocyclic group, a substituted amino group, a halogen atom, or a 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, forming a ring with the atom to which each substituent 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.

[0076] L T1 In this embodiment, the divalent group is preferably an alkylene group, a cycloalkylene group, an arylene group, a divalent heterocyclic group, or -N(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, or a group represented by -C(=O)- or -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 arylene groups and divalent heterocyclic groups in Ar T1 The examples and preferred ranges of arylene groups and divalent heterocyclic groups as divalent groups are the same as when multiple such groups exist and are bonded to each other via divalent groups to form a ring. L T1 Examples and preferred ranges of substituents that may be present are Ar T1The examples and preferred ranges of substituents that may be present are the same as those mentioned above. L T1 If multiple groups exist, they may be identical or different, and they may be directly bonded to each other or bonded via divalent groups to form a ring. However, it is preferable that they do not form a ring, as this facilitates the synthesis of the compound represented by formula (T-1). 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.

[0077] 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 aromatic hydrocarbon groups having electron-withdrawing groups, monocyclic or bicyclic to hexacyclic aromatic hydrocarbons are preferred because they result in a lower driving voltage for the light-emitting element in this embodiment. The group is obtained by removing one or more hydrogen atoms directly bonded to the ring-forming atoms from a fragrant hydrocarbon, more preferably by removing one or more hydrogen atoms directly bonded to the ring-forming atoms from a monocyclic, bicyclic, or tricyclic aromatic hydrocarbon, and even more preferably by removing one or more hydrogen atoms directly bonded to the ring-forming atoms from a monocyclic aromatic hydrocarbon. 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.

[0078] 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, aromatic hydrocarbon groups containing a group represented by -C(=O)- in the ring include aromatic hydrocarbon groups containing a group represented by -C(=O)- in the ring, as described in the section on aromatic hydrocarbon groups above, preferably groups obtained by removing one or more hydrogen atoms directly bonded to the atoms constituting the ring from a bicyclic or tricyclic aromatic hydrocarbon containing a group represented by -C(=O)- in the ring, more preferably groups obtained by removing one or more hydrogen atoms directly bonded to the atoms constituting the ring from naphthoquinone, anthraquinone, phenanthrenequinone, indenone, fluorenone, or tetralone, and even more preferably groups obtained by removing one or more hydrogen atoms directly bonded to the atoms constituting the ring from anthraquinone, phenanthrenequinone, or fluorenone, and these groups may have substituents.

[0079] 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").

[0080] The acceptor-type heterocyclic group is preferably a group obtained by removing one or more hydrogen atoms directly bonded to the atoms constituting the ring from a heterocyclic compound that does not contain a fused heterocyclic skeleton (b), and this group may have substituents. Examples of heterocyclic compounds that do not contain a fused heterocyclic skeleton (b) in the acceptor-type heterocyclic group include heterocyclic compounds that do not contain boron atoms and nitrogen atoms in the ring, as described in the section on heterocyclic groups above. 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 (preferably heterocyclic compounds that do not contain a fused heterocyclic skeleton (b)). Groups of acceptor-type heterocyclic compounds, excluding one or more hydrogen atoms directly bonded to the atoms constituting the ring, may have substituents.

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

[0082] Since the driving voltage of the light-emitting device of the present embodiment becomes lower, the acceptor-type heterocyclic compound is preferably an aromatic heterocyclic compound (preferably an aromatic heterocyclic compound that does not contain the condensed heterocyclic skeleton (b)). Since the driving voltage of the light-emitting device of the present embodiment becomes lower, the acceptor-type heterocyclic compound is preferably a heterocyclic compound (preferably a heterocyclic compound that does not contain the condensed heterocyclic skeleton (b)) 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, and more preferably a heterocyclic compound (preferably a heterocyclic compound that does not contain the condensed heterocyclic skeleton (b)) containing a group represented by =N- in the ring. Since the driving voltage of the light-emitting device of the present embodiment becomes lower, the acceptor-type heterocyclic compound is preferably a monocyclic or 2- to 7-ring heterocyclic compound (preferably a monocyclic or 2- to 7-ring heterocyclic compound that does not contain the condensed heterocyclic skeleton (b)), more preferably a monocyclic or 2- to 5-ring heterocyclic compound (preferably a monocyclic or 2- to 5-ring heterocyclic compound that does not contain the condensed heterocyclic skeleton (b)), still more preferably a monocyclic, 2-ring or 3-ring heterocyclic compound (preferably a monocyclic, 2-ring or 3-ring heterocyclic compound that does not contain the condensed heterocyclic skeleton (b)), and particularly preferably a monocyclic heterocyclic compound. The acceptor-type heterocyclic compound is preferably a heterocyclic compound containing a 5-membered ring or a 6-membered ring (preferably a heterocyclic compound not containing the condensed heterocyclic skeleton (b)) because the driving voltage of the light-emitting device of the present embodiment becomes lower, and more preferably a heterocyclic compound containing a 6-membered ring (preferably a heterocyclic compound not containing the condensed heterocyclic skeleton (b)). In the acceptor-type heterocyclic compound, examples of the heterocyclic compound containing a 5-membered ring or a 6-membered ring include acceptor-type heterocyclic compounds that do not contain the condensed heterocyclic skeleton (b) and contain a 5-membered ring or a 6-membered ring, which are exemplified in the above-mentioned section of the heterocyclic group.

[0083] The acceptor-type heterocyclic compound containing a group represented by =N- in the ring is preferably a polycyclic heterocyclic compound containing a group represented by =N- in the ring (preferably a polycyclic heterocyclic compound not containing the condensed heterocyclic skeleton (b)), or a monocyclic and 6-membered heterocyclic compound containing a group represented by =N- in the ring because the driving voltage of the light-emitting device of the present embodiment becomes lower, and more preferably a polycyclic aromatic heterocyclic compound containing a group represented by =N- in the ring (preferably a polycyclic heterocyclic compound not containing the condensed heterocyclic skeleton (b)), or a monocyclic and 6-membered aromatic heterocyclic compound containing a group represented by =N- in the ring, and still more preferably a monocyclic and 6-membered aromatic heterocyclic compound containing a group represented by =N- in the ring. These compounds may have substituents.

[0084] Examples of the polycyclic heterocyclic compound containing a group represented by =N- in the ring include polycyclic heterocyclic compounds that do not contain the condensed heterocyclic skeleton (b) and contain a group represented by =N- in the ring among the heterocyclic compounds described in the above-mentioned section of the heterocyclic group, and the compound may have substituents. In the polycyclic heterocyclic compound containing a group represented by =N- in the ring, the number of nitrogen atoms constituting the ring is preferably 1 to 5, and more preferably 1 to 3.

[0085] Examples of the monocyclic and 6-membered heterocyclic compound containing a group represented by =N- in the ring include, for example Among the heterocyclic compounds described in the section on heterocyclic groups above, examples include monocyclic and six-membered heterocyclic compounds containing a group represented by =N- within the ring, and such compounds may have substituents. In a monocyclic and six-membered heterocyclic compound containing a group represented by =N- within the ring, the number of nitrogen atoms constituting the ring is preferably 1 to 3.

[0086] The acceptor-type heterocyclic group is preferably a group obtained by removing one or more hydrogen atoms directly bonded to the ring-constituting atoms (preferably carbon atoms) from pyridine, diazabenzene, triazine, azanaphthalene, dizanaphthalene, dibenzothiophene dioxide, dibenzothiophene oxide, dibenzopyranone, azaanthracene, diazaanthracene, azaphenanthrene, dizaphenanthrene, azacarbazole, diazacarbazole, or acridone, as this further lowers the driving voltage of the light-emitting element in this embodiment. More preferably, pyridine, diazabenzene, The group is obtained by removing one or more hydrogen atoms directly bonded to the ring-forming atoms (preferably carbon atoms) from triazine, dibenzothiophene dioxide, dibenzothiophene oxide, or dibenzopyranone; more preferably, it is obtained by removing one or more hydrogen atoms directly bonded to the ring-forming atoms (preferably carbon atoms) from pyridine, diazabenzene, triazine, or dibenzopyranone; and particularly preferably, it is obtained by removing one or more hydrogen atoms directly bonded to the ring-forming atoms from pyridine, diazabenzene, 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. Ar T2 The monovalent heterocyclic group in the substituent that may be present is a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from a heterocyclic compound that does not contain a fused heterocyclic skeleton (b), and is preferably a monovalent heterocyclic group other than a monovalent donor-type heterocyclic group, and the group may further have substituents. T2 Monovalent substituents that may be present In the heterocyclic group of , heterocyclic compounds that do not contain a fused heterocyclic skeleton (b) include heterocyclic compounds that do not contain boron or nitrogen atoms in the ring, as described in the section on heterocyclic groups above. T2 The 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 that does not contain a fused heterocyclic skeleton (b), as described in the section on heterocyclic groups above, and is a heterocyclic group other than a monovalent donor-type heterocyclic group, preferably a monocyclic or bicyclic to hexacyclic heterocyclic compound (preferably a monocyclic or bicyclic to hexacyclic heterocyclic compound that does not contain a fused heterocyclic skeleton (b)) that constitutes the ring. A group from which one hydrogen atom directly bonded to the atom is removed (preferably a heterocyclic group other than a monovalent donor-type heterocyclic group), more preferably a group from a monocyclic, bicyclic, or tricyclic heterocyclic compound (preferably a monocyclic, bicyclic, or tricyclic heterocyclic compound that does not contain a fused heterocyclic skeleton (b)) from which one or more hydrogen atoms directly bonded to the atoms constituting the ring are removed (preferably a heterocyclic group other than a monovalent donor-type heterocyclic group), and even more preferably furan, thiophene, oxadiazole, thia The group is obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from diazole, diazole, triazole, pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, benzofuran, benzothiophene, azaindole, diazanaindole, benzodiazole, benzotriazole, dibenzofuran, dibenzothiophene, azacarbazole, diazacarbazole, acridone, azaanthracene, diazaanthracene, azaphenanthrene, or diazaphenanthrene, and is particularly preferably a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, dibenzofuran, dibenzothiophene, azacarbazole, or diazacarbazole, and is especially preferably a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from pyridine, diazabenzene, or triazine, and these groups may further have substituents. Ar T2Examples 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.

[0090] Ar T1 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. T1 and L T1 Examples and preferred ranges of divalent groups in cases where these groups are bonded via a divalent group to form a ring include Ar T1 The examples and preferred ranges of divalent groups are the same as those in the case where multiple divalent groups exist and are bonded to each other via divalent groups to form a ring. Ar T2 and L T1 This means that a ring may be formed by direct bonding or by bonding via a divalent group, but it is preferable that no ring is formed because the synthesis of the compound represented by formula (T-1) is easy. T2 and L T1 Examples and preferred ranges of divalent groups in cases where these groups are bonded via a divalent group to form a ring include Ar T1 The examples and preferred ranges of divalent groups are the same as those in the case where multiple divalent groups exist and are bonded to each other via divalent groups to form a ring. Ar T1 and Ar T2 This means that a ring may be formed by direct bonding or by bonding via a divalent group, but it is preferable that no ring is formed because the synthesis of the compound represented by formula (T-1) is easy. T1 and Ar T2 Examples and preferred ranges of divalent groups in cases where these groups are bonded via a divalent group to form a ring include Ar T1The examples and preferred ranges of divalent groups are the same as those in the case where multiple divalent groups exist and are bonded to each other via divalent groups to form a ring. Ar T1 and R T1 ' means that a ring is formed by direct bonding or by bonding via a divalent group. This may be done, but it is preferable not to form a ring because the compound represented by formula (T-1) is easy to synthesize. T1 and R T1 Examples and preferred ranges of divalent groups in cases where 'and are bonded via a divalent group to form a ring are Ar T1 The examples and preferred ranges of divalent groups are the same as those in the case where multiple divalent groups exist and are bonded to each other via divalent groups to form a ring. Ar T2 and R T1 ' may form a ring by direct bonding or by bonding via a divalent group, but it is preferable not to form a ring because the synthesis of the compound represented by formula (T-1) is easy. T2 and R T1 Examples and preferred ranges of divalent groups in cases where 'and are bonded via a divalent group to form a ring are Ar T1 The examples and preferred ranges of divalent groups are the same as those in the case where multiple divalent groups exist and are bonded to each other via divalent groups to form a ring.

[0091] Examples of compounds represented by formula (T-1) include those represented by the following formula. Note that in the formula, Z 1 Z represents a group represented by -N= or a group represented by -CH=. However, in each of the compounds represented by the following formulas listed as compounds represented by formula (T-1), Z 1 At least one of them represents a base represented by -N=. 2 Z represents an oxygen atom or a sulfur atom. 3 This represents a group represented by -C(=O)- or -S(=O)2-. 1 , Z 2 and Z 3 If multiple instances exist, they may be identical or different. [Chem.] [Chem.] [Chem.] [Chem.] [Chem.] [Chem.] [Chem.] [Chem.] [Chem.] [Chem.] [Chem.] [Chem.]

[0092] In the first layer, among two or more compounds represented by the formula (T-1), Ar in at least two compounds T2However, if each is independently a group obtained by removing one or more hydrogen atoms from a pyrimidine (the group may have substituents), then the at least two compounds include two compounds that satisfy requirement (i), since the driving voltage of the light-emitting element of this embodiment becomes lower.

[0093] 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 pyrimidine (the group may have substituents), and if the at least two 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).

[0094] In the first layer, Ar is present in at least two of the compounds represented by formula (T-1) T2 However, if the group is a pyrimidine from which one or more hydrogen atoms have been removed (the group may have substituents), and the at least two compounds include two compounds that satisfy requirement (i), the difference in molecular weight of these 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. In the first layer, at least two of the compounds represented by two or more formulas (T-1) Ar in the compound T2However, each is independently a pyrimidine group from which one or more hydrogen atoms have been removed (the group may have substituents), and if the at least two compounds include two compounds that satisfy requirement (i), the difference in molecular weight of these two compounds is usually 1000 or less, but may also be 500 or less, 400 or less, 350 or less, 300 or less, or 250 or less.

[0095] The first layer contains two or more compounds represented by formula (T-1), allowing multiple compounds represented by formula (T-1) to interact with each other physically, chemically, or electrically. This interaction is thought to improve the light emission characteristics, charge transport characteristics, or charge injection characteristics of the light-emitting element of this embodiment, resulting in an excellent driving voltage. 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 pyrimidine from which one or more hydrogen atoms have been removed, it is thought that by including two or more similar compounds represented by formula (T-1) with a molecular weight difference of 80 or more, 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 in this embodiment.

[0096] [Compound (B)] Compound (B) consists of a boron atom, an oxygen atom, a sulfur atom, a selenium atom, and sp 3 The compound has a fused heterocyclic skeleton (b) containing at least one atom selected from the group consisting of carbon atoms and nitrogen atoms within the ring. In compound (B), if the fused heterocyclic skeleton (b) contains nitrogen atoms, it is preferable that at least one of the nitrogen atoms in the fused heterocyclic skeleton (b) does not form a double bond, and it is more preferable that all of the nitrogen atoms in the fused heterocyclic skeleton (b) do not form a double bond. Compound (B) is preferably a compound that does not contain transition metal elements (i.e., a compound composed only of main group elements).

[0097] The number of carbon atoms in the fused heterocyclic skeleton (b), excluding the number of carbon atoms of substituents, is usually 1 to 60, preferably 5 to 50, more preferably 10 to 45, and even more preferably 15 to 40. The number of heteroatoms in the condensed heterocyclic skeleton (b), excluding the number of heteroatoms of substituents, is typically 2 to 30, preferably 2 to 15, more preferably 2 to 10, even more preferably 2 to 7, particularly preferably 2 to 6, and especially preferably 2 to 4. The number of boron atoms in the condensed heterocyclic skeleton (b), excluding the number of boron atoms in the substituents, is usually 1 to 10, preferably 1 to 5, more preferably 1 to 3, and even more preferably 1 or 2. Oxygen atom, sulfur atom, selenium atom, sp of the condensed heterocyclic skeleton (b) 3 The total number of carbon and nitrogen atoms, not including the number of substituent atoms, is usually 1 to 20, preferably 1 to 10, more preferably 1 to 5, even more preferably 1 to 4, and particularly preferably 2 or 3.

[0098] The condensed heterocyclic skeleton (b) preferably contains a boron atom and at least one atom selected from the group consisting of oxygen, sulfur, and nitrogen atoms, since the driving voltage of the light-emitting element of this embodiment is lower. It is more preferably contained a boron atom and a nitrogen atom, and even more preferably contained a boron atom and a nitrogen atom that does not form a double bond.

[0099] The condensed heterocyclic skeleton (b) is preferably a 3-15 ring condensed heterocyclic skeleton, more preferably a 3-12 ring condensed heterocyclic skeleton, and even more preferably a 5-11 ring condensed heterocyclic skeleton, as this results in a lower driving voltage for the light-emitting element of this embodiment.

[0100] A fused heterocyclic skeleton (b) can also be defined as a compound having a heterocyclic group (b') that contains the fused heterocyclic skeleton (b).

[0101] The heterocyclic group (b') consists of a boron atom, an oxygen atom, a sulfur atom, a selenium atom, and sp 3 The group may be a polycyclic heterocyclic compound containing at least one atom selected from the group consisting of carbon atoms and nitrogen atoms in the ring, from which one or more hydrogen atoms directly bonded to the atoms constituting the ring have been removed, and the group may have substituents. In the heterocyclic group (b'), the polycyclic heterocyclic compound is preferably one that contains a boron atom and at least one atom selected from the group consisting of oxygen, sulfur, and nitrogen atoms in the ring, since the driving voltage of the light-emitting element of this embodiment becomes lower. More preferably, it is a polycyclic heterocyclic compound that contains a boron atom and a nitrogen atom in the ring, and even more preferably, it is a polycyclic heterocyclic compound that contains a boron atom and a nitrogen atom that does not form a double bond in the ring. In the heterocyclic group (b'), polycyclic heterocyclic compounds result in a lower driving voltage for the light-emitting element of this embodiment. Therefore, 3 to 15-cyclic heterocyclic compounds are preferred, more preferably 3 to 12-cyclic heterocyclic compounds, and even more preferably 5 to 11-cyclic heterocyclic compounds.

[0102] The substituents that the heterocyclic group (b') may have are preferably halogen atoms, cyano groups, alkyl groups, cycloalkyl groups, alkoxy groups, cycloalkoxy groups, aryloxy groups, aryl groups, monovalent heterocyclic groups, or substituted amino groups; more preferably alkyl groups, cycloalkyl groups, 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; and particularly preferably alkyl groups, cycloalkyl groups, or aryl groups. These groups may have further substituents.

[0103] The aryl group in the substituent that the heterocyclic group (b') 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; 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; even more preferably a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from benzene, naphthalene, anthracene, phenanthrene, or fluorene; and particularly preferably a phenyl group, and these groups may have substituents. The substituents that the heterocyclic group (b') may have are preferably monovalent heterocyclic groups obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from a monocyclic or bicyclic to hexacyclic heterocyclic compound; more preferably groups obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from a monocyclic, bicyclic, or tricyclic heterocyclic compound; even more preferably groups obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from pyridine, diazabenzene, triazine, azananaphthalene, diazananaphthalene, carbazole, dibenzofuran, dibenzothiophene, phenoxazine, or phenothiazine; particularly preferably groups obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from pyridine, diazabenzene, triazine, or carbazole; and these groups may have substituents. In the substituted amino group in the substituent that the heterocyclic group (b') 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. The examples and preferred ranges of aryl groups and monovalent heterocyclic groups in the substituent of the amino group are the same as the examples and preferred ranges of aryl groups and monovalent heterocyclic groups in the substituent that the heterocyclic group (b') may have, respectively.

[0104] The substituents that the heterocyclic group (b') may have may further have are preferably halogen atoms, cyano groups, alkyl groups, cycloalkyl groups, alkoxy groups, cycloalkoxy groups, aryloxy groups, aryl groups, monovalent heterocyclic groups, or substituted amino groups; more preferably alkyl groups, cycloalkyl groups, aryl groups, monovalent heterocyclic groups, or substituted amino groups; even more preferably alkyl groups, cycloalkyl groups, or aryl groups; 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. Examples and preferred ranges of aryl groups, monovalent heterocyclic groups, and substituted amino groups in substituents that the heterocyclic group (b') may have or may have are the same as examples and preferred ranges of aryl groups, monovalent heterocyclic groups, and substituted amino groups in substituents that the heterocyclic group (b') may have.

[0105] "Nitrogen atoms that do not form a double bond" refers to nitrogen atoms that are 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 .

[0106] Compound (B) is preferably a thermally activated delayed fluorescence (TADF) compound, as this results in a lower driving voltage for the light-emitting element in this embodiment.

[0107] ΔE of compound (B) STIt may be 2.0 eV or less, 1.5 eV or less, 1.0 eV or less, or 0.80 eV or less, but since the driving voltage of the light-emitting element in this embodiment is lower, it is preferably 0.60 eV or less, more preferably 0.55 eV or less, and even more preferably 0.50 eV or less. Also, ΔE of compound (B) ST It may be 0.001 eV or more, 0.01 eV or more, 0.10 eV or more, 0.20 eV or more, 0.30 eV or more, or 0.40 eV or more.

[0108] Compound (B) is preferably a low-molecular-weight compound. The molecular weight of compound (B) is preferably 100 to 5000, more preferably 200 to 3000, even more preferably 300 to 1500, and particularly preferably 400 to 1000.

[0109] Compound (B) is preferably a compound represented by formula (1-1), formula (1-2), or formula (1-3), more preferably a compound represented by formula (1-2) or formula (1-3), and even more preferably a compound represented by formula (1-2), since the driving voltage of the light-emitting element of this embodiment becomes lower.

[0110] Ar 1 Ar 2 and Ar 3 Each of these independently results in a lower driving voltage for the light-emitting element of this embodiment. Preferably, the group is a monocyclic or bicyclic to hexacyclic aromatic hydrocarbon, or a monocyclic or bicyclic to hexacyclic heterocyclic compound, from which one or more hydrogen atoms directly bonded to the atoms constituting the ring have been removed. More preferably, the group is a monocyclic, bicyclic or tricyclic aromatic hydrocarbon, or a monocyclic, bicyclic or tricyclic heterocyclic compound, from which the ring is constituting The group is one from which one or more hydrogen atoms directly bonded to an atom have been removed, more preferably a group from a monocyclic aromatic hydrocarbon or a monocyclic heterocyclic compound from which one or more hydrogen atoms directly bonded to an atom constituting the ring have been removed, particularly preferably a group from benzene, pyridine, or diazabenzene from which one or more hydrogen atoms directly bonded to an atom constituting the ring have been removed, and most preferably a group from benzene from which one or more hydrogen atoms directly bonded to an atom constituting the ring have been removed, and these groups may have substituents. Ar 1 Ar 2 and Ar 3 Examples and preferred ranges of substituents that may be present are the same as examples and preferred ranges of substituents that may be present on the heterocyclic group (b').

[0111] Y 1 The driving voltage of the light-emitting element in this embodiment is lower, so it is preferably an oxygen atom, a sulfur atom, a group represented by -N(Ry)-, or an alkylene group, more preferably an oxygen atom, a sulfur atom, or a group represented by -N(Ry)-, and even more preferably a group represented by -N(Ry)-, and these groups may have substituents.

[0112] Y 2 and Y 3 Each of these groups independently results in a lower driving voltage for the light-emitting element of this embodiment, and is therefore preferably a single bond, an oxygen atom, a sulfur atom, a selenium atom, a group represented by -N(Ry)-, a group represented by -B(Ry)-, an alkylene group, or a cycloalkylene group; more preferably a single bond, an oxygen atom, a sulfur atom, a group represented by -N(Ry)-, a group represented by -B(Ry)-, or an alkylene group; even more preferably an oxygen atom, a sulfur atom, a group represented by -N(Ry)-, or an alkylene group; particularly preferably an oxygen atom, a sulfur atom, or a group represented by -N(Ry)-; and especially preferably a group represented by -N(Ry)-, and these groups may have substituents.

[0113] Y 2 and Y 3The arylene group in this product is preferably a monocyclic or bicyclic to hexacyclic aromatic hydrocarbon from which two hydrogen atoms directly bonded to the carbon atoms constituting the ring have been removed; more preferably a monocyclic, bicyclic, or tricyclic aromatic hydrocarbon from which two hydrogen atoms directly bonded to the carbon atoms constituting the ring have been removed; even more preferably a group from benzene, naphthalene, anthracene, phenanthrene, dihydrophenanthrene, or fluorene from which two hydrogen atoms directly bonded to the carbon atoms constituting the ring have been removed; particularly preferably a group from benzene, naphthalene, or fluorene from which two hydrogen atoms directly bonded to the carbon atoms constituting the ring have been removed; and especially preferably a phenylene group. These groups may have substituents. Y 2 and Y 3 The divalent heterocyclic group in 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, dibenzofuran, dibenzothiophene, carbazole, azacarbazole, diazacarbazole, phenoxazine, phenothiazine, or 9,10-dihydroacridine Alternatively, the group is obtained by removing two hydrogen atoms directly bonded to the ring-forming atoms (preferably carbon atoms) from 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 atoms (preferably carbon atoms) from pyridine, diazabenzene, or triazine, and these groups may have substituents. Y 1 , Y 2 and Y 3The alkylene group in is preferably a methylene group, an ethylene group, or a propylene group, more preferably a methylene group, and these groups may have substituents.

[0114] Since the driving voltage of the light-emitting element in this embodiment becomes lower, Y 1 , Y 2 and Y 3 Preferably, all of them are oxygen atoms, sulfur atoms, or groups represented by -N(Ry)-, Y 1 , Y 2 and Y 3 It is more preferable that all of these are groups represented by -N(Ry)-.

[0115] Y 1 , Y 2 and Y 3 Examples and preferred ranges of substituents that may be present are the same as examples and preferred ranges of substituents that may be present on the heterocyclic group (b').

[0116] Ry 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. Examples and preferred ranges of aryl groups and monovalent heterocyclic groups in Ry are the same as examples and preferred ranges of aryl groups and monovalent heterocyclic groups in substituents that the heterocyclic group (b') may have. Examples and preferred ranges of substituents that Ry may have are the same as examples and preferred ranges of substituents that the heterocyclic group (b') may have.

[0117] Y 1 and Ar 1 This refers to a ring (for example, Y) that is bonded directly or via a divalent group. 1 and Ar 1 A ring containing boron (B) and Y 1 Ar 1 and Ar 2It is possible to form a ring (other than the ring composed of the above), but it is preferable not to form a ring because it facilitates the synthesis of compound (B). Y 1 and Ar 1 When these groups are bonded via a divalent group to form a ring, the divalent group is preferably an alkylene group, a cycloalkylene group, an arylene group, a divalent heterocyclic group, or -N(R 0 A base represented by )-, -B(R 0 A group represented by -)-, a group represented by -O-, a group represented by -S-, or a group represented by -Se-, more preferably an alkylene group, a cycloalkylene group, -N(R 0 A base represented by )-, -B(R 0 A group represented by -, a group represented by -O-, a group represented by -S-, or a group represented by -Se-, more preferably an alkylene group, -N(R 0 A group represented by -, a group represented by -O-, or a group represented by -S-, and particularly preferably a group represented by -O-, a group represented by -S-, or -N(R 0 A group represented by -N(R 0 These are groups represented by )-, and these groups may have substituents. Y 1 and Ar 1 When a ring is formed by bonding via a divalent group, examples and preferred ranges of the arylene group, divalent heterocyclic group, and alkylene group in the divalent group are, respectively, Y 2 and Y 3 The examples and preferred ranges of arylene groups, divalent heterocyclic groups, and alkylene groups are the same as those in [the relevant section]. Y 1 and Ar 1 When a ring is formed by a bond between two components via a divalent group, examples and preferred ranges of substituents that the divalent group may have are: Y 2 and Y 3 The examples and preferred ranges of substituents that may be present are the same as those mentioned above. Y 1 and Ar 1 When R is bonded to the divalent group via a divalent group to form a ring, 0The preferred range for Ry is the same as the preferred range for Ry.

[0118] Y 1 and Ar 2 This refers to a ring (for example, Y) that is bonded directly or via a divalent group. 1 and Ar 2 A ring containing boron (B) and Y 1 Ar 1 and Ar 2 It is possible to form a ring (other than the ring composed of), but it is preferable not to form a ring because the synthesis of compound (B) is easier. 1 and Ar 2 Examples and preferred ranges of divalent groups in cases where they are bonded via a divalent group to form a ring are Y 1 and Ar 1 The examples and preferred ranges of divalent groups are the same as those in cases where the groups are bonded via a divalent group to form a ring. Y 2 and Ar 1 This refers to a ring (for example, Y) that is bonded directly or via a divalent group. 2 and Ar 1 A ring containing boron (B) and Y 2 Ar 1 and Ar 3 It is possible to form a ring (other than the ring composed of), but it is preferable not to form a ring because the synthesis of compound (B) is easier. 2 and Ar 1 When two groups are bonded via a divalent group to form a ring, Examples and preferred ranges of divalent groups are Y 1 and Ar 1 The examples and preferred ranges of divalent groups are the same as those in cases where the groups are bonded via a divalent group to form a ring. Y 2 and Ar 3 This refers to a ring (for example, Y) that is bonded directly or via a divalent group. 2 and Ar 3 A ring containing boron (B) and Y 2 Ar 1 and Ar 3It is possible to form a ring (other than the ring composed of), but it is preferable not to form a ring because the synthesis of compound (B) is easier. 2 and Ar 3 Examples and preferred ranges of divalent groups in cases where they are bonded via a divalent group to form a ring are Y 1 and Ar 1 The examples and preferred ranges of divalent groups are the same as those in cases where the groups are bonded via a divalent group to form a ring. Y 3 and Ar 2 This refers to a ring (for example, Y) that is bonded directly or via a divalent group. 3 and Ar 2 A ring containing boron (B) and Y 3 Ar 2 and Ar 3 It is possible to form a ring (other than the ring composed of), but it is preferable not to form a ring because the synthesis of compound (B) is easier. 3 and Ar 2 Examples and preferred ranges of divalent groups in cases where they are bonded via a divalent group to form a ring are Y 1 and Ar 1 The examples and preferred ranges of divalent groups are the same as those in cases where the groups are bonded via a divalent group to form a ring. Y 3 and Ar 3 This refers to a ring (for example, Y) that is bonded directly or via a divalent group. 3 and Ar 3 A ring containing boron (B) and Y 3 Ar 2 and Ar 3 It is possible to form a ring (other than the ring composed of), but it is preferable not to form a ring because the synthesis of compound (B) is easier. 3 and Ar 3 Examples and preferred ranges of divalent groups in cases where they are bonded via a divalent group to form a ring are Y 1 and Ar 1 The examples and preferred ranges of divalent groups are the same as those in cases where the groups are bonded via a divalent group to form a ring.

[0119] Examples of compound (B) include the compound represented by the following formula, as well as compounds B1 to B3 described later. Note that in the formula, Z 2 This has the same meaning as above. 2 If multiple instances exist, they may be identical or different.

[0120] [ka]

[0121] [ka]

[0122] [First composition] The first layer may contain a composition (hereinafter also referred to as "the first composition") comprising compound (B), 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, light-emitting materials, and antioxidants. However, in the first composition, the hole transport material, hole injection material, electron transport material, electron injection material, and light-emitting material are different from compound (B) and the compound represented by formula (T-1).

[0123] (Hole transport material) Hole transport materials are classified into low-molecular-weight compounds and high-molecular-weight compounds. Hole transport materials may also have crosslinking groups. Examples of low molecular weight compounds include triphenylamine and its derivatives, N,N'-di-1-naphthyl-N,N'-diphenylbenzidine (α-NPD), and aromatic amine compounds such as N,N'-diphenyl-N,N'-di(m-tolyl)benzidine (TPD). Examples of polymer compounds include polyvinylcarbazole and its derivatives; and polyarylene and its derivatives having aromatic amine structures in the side chain or main chain. The polymer compound may also be a compound to which an electron-accepting site is attached. Examples of electron-accepting sites include fullerene, tetrafluorotetracyanoquinodimethane, tetracyanoethylene, and trinitrofluorenone.

[0124] 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 compound (B) 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.

[0125] (electron transport material) Electron transport materials are classified into low-molecular-weight compounds and high-molecular-weight compounds. Electron transport materials may also contain crosslinking groups. Examples of low molecular weight compounds include metal complexes with 8-hydroxyquinoline as a ligand, oxadiazoles, anthraquinodimethanes, benzoquinones, naphthoquinones, anthraquinones, tetracyanoanthraquinodimethanes, fluorenones, diphenyldicyanoethylenes and diphenoquinones, and their derivatives. Examples of polymer compounds include polyphenylene, polyfluorene, and their derivatives. The polymer compounds may be metal-doped.

[0126] 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 compound (B) 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.

[0127] (Hole injection materials and electron injection materials) Hole injection materials and electron injection materials are classified into low-molecular-weight compounds and high-molecular-weight compounds, respectively. Hole injection materials and electron injection materials may also have crosslinking groups. Examples of low molecular weight compounds include metal phthalocyanines such as copper phthalocyanine; carbon; metal oxides such as molybdenum and tungsten; and metal fluorides such as lithium fluoride, sodium fluoride, cesium fluoride, and potassium fluoride. Examples of polymer compounds include polyaniline, polythiophene, polypyrrole, polyphenylene vinylene, polythienylene vinylene, polyquinoline and polyquinoxaline, and their derivatives; and conductive polymers such as polymers containing aromatic amine structures in the main chain or side chains.

[0128] 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 compound (B) 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.

[0129] Ion doping When the hole injection material or electron injection material contains a conductive polymer, the electrical conductivity of the conductive polymer is preferably 1 × 10⁻⁶. -5 S / cm~1×10 3 The density is S / cm. To achieve this electrical conductivity within the conductive polymer range, an appropriate amount of ions can be doped into the conductive polymer. The type of ion used for doping depends on the material: anions for hole-injection materials and cations for electron-injection materials. Examples of anions include polystyrene sulfonate ions, alkylbenzene sulfonate ions, and camphor sulfonate ions. Examples of cations include lithium ions, sodium ions, potassium ions, and tetrabutylammonium ions. The doping ions may be used individually or in combination of two or more.

[0130] (Luminescent material) Luminescent materials are classified into low-molecular-weight compounds and high-molecular-weight compounds. Luminescent materials may also have crosslinking groups.

[0131] Examples of low molecular weight compounds include naphthalene and its derivatives, anthracene and its derivatives, perylene and its derivatives, and triplet luminescence complexes with iridium, platinum, or europium as the central metal. Examples of triplet-luminescent complexes include the following metal complexes.

[0132] [ka]

[0133] [ka]

[0134] [ka]

[0135] [ka]

[0136] [ka]

[0137] 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.

[0138] 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 compound (B) 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.

[0139] (Antioxidant) The antioxidant can be any compound that is soluble in the same solvent as compound (B) and the compound represented by formula (T-1) and does not inhibit luminescence and charge transport. Examples include phenolic antioxidants and phosphorus-based antioxidants.

[0140] 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 compound (B) 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.

[0141] [First Ink] The first layer can be formed, for example, using a composition (hereinafter also referred to as "first ink") containing compound (B), 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.

[0142] 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.

[0143] 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.

[0144] 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 compound (B) and all compounds represented by formula (T-1) is 100 parts by mass.

[0145] <Second Layer> In the light-emitting element of this embodiment, the second layer is a layer containing a crosslinked compound having a crosslinking group. The second layer may contain only one type of crosslinked material, or it may contain two or more types.

[0146] In the light-emitting element of this embodiment, the number of crosslinked compounds containing crosslinking groups in the second layer is usually 1 to 10 types, preferably 1 to 5 types, more preferably 1 to 3 types, even more preferably 1 or 2 types, and particularly preferably 1 type, as this facilitates the manufacture of the light-emitting element of this embodiment.

[0147] In the second layer, the content of the crosslinked compound having a crosslinking group is limited to a range that allows the second layer to function as such. The content of the crosslinked compound having a crosslinking group in the second layer may be 1 to 100% by mass based on the total amount of the second layer, and is preferably 10 to 100% by mass, and more preferably 3%, as this results in a lower driving voltage for the light-emitting element of this embodiment. The amount is 0 to 100% by mass, more preferably 50 to 100% by mass, particularly preferably 70 to 100% by mass, and especially preferably 90 to 100% by mass.

[0148] [Crosslinked compounds containing crosslinking groups] A crosslinked compound of a crosslinking group can be obtained, for example, by crosslinking the compound having a crosslinking group using the methods and conditions described later. The compound having a crosslinking group may be a low-molecular-weight compound having a crosslinking group, or a high-molecular-weight compound having a crosslinking group.

[0149] In a compound having a crosslinking group, the crosslinking group is preferably at least one crosslinking group selected from group A of crosslinking groups (i.e., at least one crosslinking group selected from the crosslinking groups represented by formulas (XL-1) to (XL-19)), and more preferably (XL-1) to (XL-4), (XL-7) to (XL-10), or (XL-14) to (XL-19). The crosslinking group is represented by formula (XL-1), formula (XL-3), formula (XL-7), formula (XL-9), formula (XL-10), or formulas (XL-16) to (XL-19), and is particularly preferably represented by formula (XL-1), formula (XL-7), formula (XL-10), formula (XL-16), or formula (XL-17), and is especially preferably represented by formula (XL-1), formula (XL-10), formula (XL-16), or formula (XL-17). Examples and preferred ranges of substituents that may be present in a crosslinking group selected from group A are as follows: Y1 The examples and preferred ranges of substituents that the group represented by may have are the same. A compound having a crosslinking group may contain only one crosslinking group selected from group A, or it may contain two or more.

[0150] (Polymer compounds containing crosslinking groups) A polymer compound having a crosslinking group is preferable because it exhibits superior crosslinking properties and lowers the driving voltage of the light-emitting element in this embodiment. In other words, a polymer compound having a crosslinking group is preferable to be a polymer compound containing a structural unit having a crosslinking group. Examples and preferred ranges of crosslinking groups in polymer compounds having crosslinking groups and structural units having crosslinking groups are the same as examples and preferred ranges of crosslinking groups in compounds having crosslinking groups. When a polymer compound having a crosslinking group contains a structural unit having a crosslinking group, the content of the structural unit having a crosslinking group should be within a range that allows the polymer compound to function as a polymer compound having a crosslinking group. When a polymer compound having a crosslinking group contains a structural unit having a crosslinking group, the content of the structural unit having a crosslinking group should be, for example, 0.1 to 100 mol% of the total content of structural units contained in the polymer compound having a crosslinking group, preferably 1 to 99 mol%, more preferably 2 to 90 mol%, even more preferably 3 to 70 mol%, and particularly preferably 5 to 50 mol%. The structural unit having a crosslinking group may be present as one type or as two or more types in the polymer compound having a crosslinking group.

[0151] The component having a crosslinking group is preferably a component represented by formula (Z) or formula (Z'), since the driving voltage of the light-emitting element in this embodiment becomes lower.

[0152] • Constituent units represented by formula (Z) n is usually an integer from 1 to 10, and the driving voltage of the light-emitting element in this embodiment becomes lower. Preferably, it is an integer between 1 and 7, more preferably an integer between 1 and 4, even more preferably 1 or 2, and particularly preferably 2. 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.

[0153] Ar Z Examples of hydrocarbon groups in this context include aromatic hydrocarbon groups which may have substituents and aliphatic hydrocarbon groups which may have substituents. Z The hydrocarbon groups in this context include groups formed by the bonding of multiple such groups.

[0154] Ar ZExamples 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.

[0155] Ar Z 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.

[0156] Ar Z Examples of heterocyclic groups in this context include groups obtained by removing n hydrogen atoms from a divalent heterocyclic group, and these groups may have substituents. Examples and preferred ranges of these divalent heterocyclic groups include Ar, which will be described later. Y1 Examples and preferred ranges of divalent heterocyclic groups in this context are given.

[0157] Ar Z 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 Z The examples and preferred ranges of hydrocarbon groups and heterocyclic groups are the same as those in the above. Ar Z 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.

[0158] Ar Z 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.

[0159] L AExamples and preferred ranges of arylene groups represented by Ar are described below. Y1 Examples and preferred ranges of arylene groups represented by are given, and since the 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.

[0160] 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.

[0161] 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.

[0162] 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 Examples and preferences of aryl groups and monovalent heterocyclic groups in substituents that may be present. It is the same as the range of what is considered acceptable.

[0163] Ar Z , L A Examples and preferred ranges of substituents that the group represented by and R' may have are given below in Ar Y1 The examples and preferred ranges of substituents that the group represented by may have are the same. Examples and preferred ranges of crosslinking groups in X are the same as examples and preferred ranges of crosslinking groups in compounds having crosslinking groups.

[0164] The constituent unit represented by formula (Z) exhibits excellent stability and crosslinkability in polymer compounds containing the constituent unit having a crosslinking group. Therefore, the constituent unit is preferably present in an amount of 0.5 to 80 mol%, more preferably 3 to 65 mol%, and even more preferably 5 to 50 mol%, relative to the total amount of constituent units contained in the polymer compound containing the constituent unit having a crosslinking group. The constituent unit represented by formula (Z) may be present as one type or as two or more types in a polymer compound containing a constituent unit having a crosslinking group.

[0165] · 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.

[0166] Ar 5 Examples and preferred ranges of hydrocarbon groups and heterocyclic groups in Ar Z 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 Z The examples and preferred ranges of groups in which at least one hydrocarbon group and at least one heterocyclic group are directly bonded are the same as in the above. Ar 5Since 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.

[0167] Ar 4 and Ar 6 Each of these is an arylene group, which may preferably have substituents, as it lowers the driving voltage of the light-emitting element of this embodiment. Ar 4 and Ar 6 Examples and preferred ranges of arylene groups in Ar are described below. X1 Ar X2 Ar X3 and Ar X4 The examples and preferred ranges of arylene groups are the same as those in the above. Ar 4 and Ar 6 Examples and preferred ranges of divalent heterocyclic groups in are described below in Ar X1 Ar X2 Ar X3 and Ar X4 The examples and preferred ranges of divalent heterocyclic groups are the same as those in [the relevant section]. Ar 4 ~Ar 6 Examples and preferred ranges of substituents that the group represented by may have are, as described below, Ar Y1 The examples and preferred ranges of substituents that the group represented by may have are the same.

[0168] 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'.

[0169] The examples and preferred ranges of crosslinking groups in X' are the same as the examples and preferred ranges of crosslinking groups 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 RX3 The examples and preferred ranges of aryl groups and monovalent heterocyclic groups are the same as those in [the relevant section]. X' is preferably a bridging group, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, more preferably a bridging group, an aryl group, or a monovalent heterocyclic group, and even more preferably a bridging group or an aryl group, and these groups may have substituents. Examples and preferred ranges of substituents that the group represented by X' may have are shown below in Ar Y1 The examples and preferred ranges of substituents that the group represented by may have are the same.

[0170] The constituent unit represented by formula (Z') exhibits excellent stability and crosslinkability in polymer compounds containing the constituent unit having a crosslinking group. Therefore, the constituent unit is preferably present in an amount of 0.5 to 50 mol%, more preferably 3 to 30 mol%, and even more preferably 5 to 20 mol%, relative to the total amount of constituent units contained in the polymer compound containing the constituent unit having a crosslinking group. The constituent unit represented by formula (Z') may be present as one type or as two or more types in a polymer compound containing a constituent unit having a crosslinking group.

[0171] Examples of structural units having a bridging group include the structural unit represented by the following formula. In the formula, Z 2 This expresses the same meaning as above. X A X represents a crosslinking group. A If multiple instances exist, they may be identical or different. A The examples and preferred ranges are the same as the preferred ranges for the crosslinking group in X.

[0172] [ka]

[0173] [ka]

[0174] [ka]

[0175] [ka]

[0176] [ka]

[0177] Other constituent units The polymer compound having a crosslinking group is preferably a polymer compound (hereinafter also referred to as "polymer compound (2')") that contains at least one constituent unit selected from the group consisting of constituent units represented by formula (X) and constituent units represented by formula (Y), since the driving voltage of the light-emitting element of this embodiment becomes lower. The polymer compound (2') is a polymer compound that contains at least one structural unit selected from the group consisting of structural units represented by formula (X) and structural units represented by formula (Y), and also contains a structural unit having a crosslinking group. The polymer compound (2') is preferably a polymer compound comprising at least one 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 a crosslinking group, 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 units having crosslinking groups are different from the structural units represented by formula (X) and formula (Y). The polymer compound (2') preferably contains the constituent unit represented by formula (Y) because it 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.

[0178] [ka]

[0179] [In the formula, a X1 and a X2 Each of these independently represents a non-negative integer. Ar X1 and Ar X3 Each of these independently represents an arylene group or a divalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other to form a ring with the atom to which they are bonded. Ar X2 and Ar X4 Each of these independently represents an arylene group, a divalent heterocyclic group, or a divalent group formed by the direct bonding of at least one arylene group and at least one divalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may bond to each other to form a ring with the atom to which they are bonded. X2 If multiple instances exist, they may be identical or different. X4 If multiple instances exist, they may be identical or different from one another. R X1 , R X2 and R X3 Each of these independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other 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.

[0180] [ka]

[0181] [In the formula, Ar Y1 This represents an arylene group, a divalent heterocyclic group, or a divalent group formed by the direct bonding of at least one arylene group and at least one divalent heterocyclic group, where these groups may have substituents. If multiple substituents exist, they may be identical or different, and may bond to each other, forming a ring with the atom to which each substituent is bonded.

[0182] When 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 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 10 to 70 mol%, as this provides excellent hole transport properties for polymer compound (2') and lowers the driving voltage of the light-emitting element of this embodiment. The percentage is between 20 and 60 moles. The constituent unit represented by formula (X) may be present in the polymer compound (2') as one type or as two or more types.

[0183] 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.

[0184] • 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.

[0185] 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 atoms constituting the ring 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 atoms constituting the ring have been removed. Further preferably, pyridine, diazabenzene, triazine, azananaphthalene, diazananaphthalene, carbazole, dibenzofuran, dibenzothiophene, phenoxazine, phenothiazine, 9, The group is obtained by removing two hydrogen atoms directly bonded to the ring-forming atoms (preferably carbon atoms or nitrogen atoms, more preferably carbon atoms) from 10-dihydroacridine or 5,10-dihydrophenazine, and is particularly preferred to be a group obtained by removing two hydrogen atoms directly bonded to the ring-forming atoms (preferably carbon atoms or nitrogen atoms, more preferably carbon atoms) from pyridine, diazabenzene, triazine, carbazole, dibenzofuran, dibenzothiophene, phenoxazine, or phenothiazine, and these may have substituents.

[0186] Ar Y1 In a divalent group in which at least one arylene group and at least one divalent heterocyclic group are directly bonded, the preferred ranges for the arylene group and the divalent heterocyclic group are, respectively, Ar Y1This is the same as the preferred range for the arylene group and the divalent heterocyclic group represented by .

[0187] 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.

[0188] [ka]

[0189] 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.

[0190] 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.

[0191] 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.

[0192] Ar Y1 The monovalent heterocyclic 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 heterocycle, since this lowers the driving voltage of the light-emitting element of this embodiment. More preferably, it is a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from a monocyclic, bicyclic, or tricyclic heterocycle. Even more preferably, it is a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from pyridine, diazabenzene, triazine, azananaphthalene, diazananaphthalene, carbazole, dibenzofuran, dibenzothiophene, phenoxazine, phenothiazine, 9,10-dihydroacridine, or 5,10-dihydrophenazine. Particularly preferably, it is a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from pyridine, diazabenzene, triazine, carbazole, dibenzofuran, dibenzothiophene, phenoxazine, or phenothiazine. These groups may further have substituents.

[0193] 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.

[0194] 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.

[0195] 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.

[0196] [ka]

[0197] [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 R 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. 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.

[0198] 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; even more preferably a hydrogen atom or an alkyl group, and these groups may have substituents.

[0199] In equation (Y-1), R Y1 at least one of (preferably R) Y1 At least two of these are preferably alkyl groups, cycloalkyl groups, alkoxy groups, cycloalkoxy groups, aryl groups, aryloxy groups, as this lowers the driving voltage of the light-emitting element in this embodiment. The group is a monovalent heterocyclic group, a substituted amino group, or a fluorine atom, more preferably an alkyl group, a cycloalkyl group, an aryl group, a monovalent heterocyclic group, or a substituted amino group, even more preferably an alkyl group, a cycloalkyl group, or an aryl group, and particularly preferably an alkyl group, and these groups may have substituents.

[0200] 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.

[0201] 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-.

[0202] 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.

[0203] [ka]

[0204] [ka]

[0205] [ka]

[0206] [ka]

[0207] • 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.

[0208] 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.

[0209] 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 X4 Examples 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 Y1The 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.

[0210] Ar X1 ~Ar X4 and R X1 ~R X3 Examples and preferred ranges of substituents that the group represented by may have are Ar Y1 The examples and preferred ranges of substituents that the group represented by may have are the same.

[0211] 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.

[0212] [ka]

[0213] [ka]

[0214] [ka]

[0215] [ka]

[0216] Examples of polymer compounds for the second layer include polymer compounds P-1 to P-12 shown in Table 1. Here, "others" refers to constituent units other than those represented by formula (Z), formula (Z'), formula (X), and formula (Y).

[0217] [Table 1]

[0218] The polymer compound having a crosslinking group may be a block copolymer, a random copolymer, an alternating copolymer, a graft copolymer, or any other form, but it is preferably a copolymer obtained by copolymerizing multiple types of raw material monomers. The number-average molecular weight of the polymer compound having a crosslinking group, in terms of polystyrene, is preferably 5 × 10⁻⁶. 3 ~1 × 10 6 Therefore, 1 × 10 4 ~5×10 5 And more preferably 2 × 10 4 ~1 × 10 5 The weight-average molecular weight of the polymer compound having a crosslinking group, in terms of polystyrene, is preferably 1 × 10⁻⁶. 4 ~2×10 6 Therefore, more preferably 2 × 10 4 ~1 × 10 6 And more preferably 5 × 10 4 ~5×10 5 And, particularly preferably, 1 × 10 5 ~3×10 5 That is the case.

[0219] • Method for producing polymer compounds having crosslinking groups Polymer compounds having crosslinking groups can be produced using known polymerization methods described in Chemical Review (Chem. Rev.), Vol. 109, pp. 897-1091 (2009), etc. Examples include polymerization by coupling reactions using transition metal catalysts such as the Suzuki reaction, Yamamoto reaction, Buchwald reaction, Stille reaction, Negishi reaction, and Kumada reaction. In the polymerization method described above, methods for introducing the monomer include introducing the entire amount of monomer into the reaction system at once, introducing a portion of the monomer and reacting it, then introducing the remaining monomer all at once, continuously, or in installments, and introducing the monomer continuously or in installments. Examples of transition metal catalysts include palladium catalysts and nickel catalysts. Post-treatment of the polymerization reaction is carried out by known methods, such as removing water-soluble impurities by liquid-liquid separation, or by adding the reaction solution after polymerization to a lower alcohol such as methanol, filtering the precipitate, and then drying it, either alone or in combination. If the purity of the polymer compound in the second layer is low, it can be purified by conventional methods such as recrystallization, reprecipitation, continuous extraction using a Soxhlet extractor, or column chromatography.

[0220] (Low molecular weight compounds containing crosslinking groups) The low molecular weight compound having a crosslinking group results in a lower driving voltage for the light-emitting element of this embodiment. Preferably, the compound is represented by formula (Z'').

[0221] m B1 The examples and preferred ranges are the same as the examples and preferred ranges for mA. m B2 The example and preferred range are the same as the example and preferred range for c. m B3 The examples and preferred ranges for m are the same as the examples and preferred ranges for m. Ar 7 Examples and preferred ranges are, 5 This is the same as the example and preferred range. L B1Examples and preferred ranges are K A This is the same as the example and preferred range. The examples and preferred ranges for R''' are the same as the examples and preferred ranges for R''. The examples and preferred ranges of X'' are the same as the examples and preferred ranges of X'.

[0222] Examples of low molecular weight compounds having a crosslinking group include the compounds listed below, as well as the compound HTL-M2 described later.

[0223] [ka]

[0224] [ka]

[0225] [ka]

[0226] [ka]

[0227] [Second composition] The second layer may contain a composition (hereinafter also referred to as "the second composition") comprising a crosslinked compound having a crosslinking group and at least one material selected from the group consisting of a hole transport material, a hole injection material, an electron transport material, an electron injection material, a light-emitting material, and an antioxidant. In the second layer, the hole transport material, the hole injection material, the electron transport material, the electron injection material, and the light-emitting material are different from the crosslinked compound having a crosslinking group. The second composition may contain, individually or in combination of, a crosslinked compound having a crosslinking group, a hole transport material, a hole injection material, an electron transport material, an electron injection material, a light-emitting material, and an antioxidant. Examples and preferred ranges of hole transport materials, hole injection materials, electron transport materials, electron injection materials, light-emitting materials, and antioxidants contained in the second composition are the same as examples and preferred ranges of hole transport materials, hole injection materials, electron transport materials, electron injection materials, light-emitting materials, and antioxidants contained in the first composition.

[0228] In the second composition, the total content of the crosslinked compound having a crosslinking group, hole transport material, hole injection material, electron transport material, electron injection material, light-emitting material, and antioxidant may be within a range that allows the function of the second composition to be achieved. In the second composition, the total content of the crosslinked compound having a crosslinking group, hole transport material, hole injection material, electron transport material, electron injection material, light-emitting material, and antioxidant may be, for example, 1 to 100% by mass, 10 to 100% by mass, 30 to 100% by mass, 50 to 100% by mass, 70 to 100% by mass, or 90 to 100% by mass, based on the total amount of the second composition. In the second composition, the content of the hole transport material, hole injection material, electron transport material, electron injection material, and light-emitting material is typically 1 to 10,000 parts by mass, when the content of the crosslinked compound having a crosslinking group is 100 parts by mass. In the second composition, the content of the antioxidant is typically 0.00001 to 10 parts by mass, when the content of the crosslinked compound having a crosslinking group is 100 parts by mass.

[0229] (Second ink) The second layer can be formed using, for example, a composition containing a compound having a crosslinking group and a solvent (hereinafter also referred to as the "second ink"). The second ink may contain one or more crosslinking compounds and solvents. 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 content of the crosslinking compound is 100 parts by mass.

[0230] The second ink may further contain at least one selected from the group consisting of hole transport materials, hole injection materials, electron transport materials, electron injection materials, light-emitting materials, and antioxidants. Examples and preferred ranges of hole transport materials, electron transport materials, hole injection materials, electron injection materials, light-emitting materials, and antioxidants that the second ink may further contain are the same as examples and preferred ranges of hole transport materials, electron transport materials, hole injection materials, electron injection materials, light-emitting materials, and antioxidants contained in the second composition. The second ink may further contain hole transport material, electron transport material, hole injection material, electron injection material, and light-emitting material, each typically in amounts of 1 to 10,000 parts by mass, based on 100 parts by mass of the crosslinking compound. The second ink may further contain antioxidant, typically in amounts of 0.00001 to 10 parts by mass, based on 100 parts by mass of the crosslinking compound.

[0231] <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.

[0232] 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.

[0233] 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.

[0234] 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.

[0235] 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.

[0236] When the second layer is a hole transport layer provided between the anode and the first layer, the present invention Since the driving voltage of the optical element becomes lower, 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 electron transport layer between the cathode and the first layer.

[0237] 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 the electron transport layer between the cathode and the first layer.

[0238] 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.

[0239] 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.

[0240] (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

[0241] 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.

[0242] 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.

[0243] [First light-emitting layer] The first light-emitting layer is typically the first layer.

[0244] [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.

[0245] [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.

[0246] [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. The light-emitting element of this embodiment has an electron transport layer, and also a hole injection layer described later, and the second light-emitting element described above. If the optical layer and the aforementioned hole transport layer are not the second layer, the electron transport layer is preferably the second layer.

[0247] [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.

[0248] [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.

[0249] [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.

[0250] 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.

[0251] 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.

[0252] 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.

[0253] Methods for forming the anode and cathode include, for example, vacuum deposition, sputtering, ion plating, plating, and lamination.

[0254] [Manufacturing method for generating light-emitting elements] In the method for manufacturing a light-emitting element of this embodiment, when using a low molecular weight compound, examples of dry methods such as vacuum deposition and wet methods described in the section on the first ink can be used, and when using a polymer compound, examples of wet methods described in the section on the first ink can be used. In the method for manufacturing an optical element, the first layer, the second layer, and the layers other than the first and second layers may be formed using the various inks and materials described above by the wet method described in the section on the first ink, or by a dry method such as vacuum deposition.

[0255] 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.

[0256] When the first layer is formed by a wet process, it is preferable to use the first ink, as this facilitates the manufacture of the light-emitting element of the embodiment. That is, it is preferable to form the first layer by a wet process using the first ink. When the second layer is formed by a wet process, it is preferable to use a second ink, as this facilitates the manufacture of the light-emitting element of the embodiment. That is, it is preferable to form the second layer by a wet process using the second ink.

[0257] In the method for manufacturing a light-emitting element of this embodiment, a layer containing a crosslinked compound having a crosslinking group (for example, a second layer) can be formed, for example, by forming a layer containing a compound having a crosslinking group and then heating or irradiating it with light (preferably heating) to crosslink the compound having a crosslinking group contained in the layer. When the compound having a crosslinking group is contained in the second layer in a crosslinked state (a crosslinked compound having a crosslinking group), the layer is substantially insoluble in the solvent. Therefore, a layer containing a crosslinked compound having a crosslinking group can be suitably used for lamination in the manufacturing of a light-emitting element of this embodiment.

[0258] From the above viewpoint, in the method for manufacturing a light-emitting element of this embodiment, the step of forming a second layer preferably includes the step of forming a layer containing a compound having a crosslinking group, and then crosslinking the compound having a crosslinking group contained in the layer to form a second layer containing a crosslinked body of the compound having a crosslinking group. In the step of forming the second layer, as a method for crosslinking the compound having a crosslinking group, a method of crosslinking by heating or light irradiation is preferred, and a method of crosslinking by heating is more preferred, as it facilitates the manufacture of the light-emitting element of this embodiment.

[0259] 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.

[0260] One step in forming the second layer is, for example, to form a layer by a wet process using a second ink, and then to crosslink the crosslinking group compound contained in the layer to form the second layer.

[0261] 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. Solid-liquid extraction is performed on the first layer, the second layer, or layers other than the first and second layers using organic solvents such as toluene, xylene, chloroform, and tetrahydrofuran. It is possible to separate components that are substantially insoluble in organic solvents (insoluble components) from components that are soluble in organic solvents (soluble components). Insoluble components can be analyzed by infrared spectroscopy or nuclear magnetic resonance spectroscopy, while soluble components can be analyzed by nuclear magnetic resonance spectroscopy or mass spectrometry.

[0262] 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.

[0263] 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.

[0264] [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).

[0265] Although preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. [Examples]

[0266] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0267] In the examples, the molecular weight of the compounds was calculated using the Molecular Weight value from ChemDraw Professional 22.2 (Revvity Signals Software).

[0268] 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-V detector was used. An IS detector (manufactured by Shimadzu Corporation, product name: SPD-10Avp) was used.

[0269] <Synthesis Example 1> Synthesis of Compounds M1-M8 Compound M1 was synthesized according to the method described in Japanese Patent Publication No. 2011-174062. Compound M2 was synthesized according to the method described in International Publication No. 2005 / 049546. Compound M3 was synthesized according to the method described in International Publication No. 02 / 045184. Compound M4 was synthesized according to the method described in Japanese Patent Publication No. 2010-215886. Compound M5 was synthesized according to the method described in Japanese Patent Publication No. 2008-106241. Compound M6 was synthesized according to the method described in International Publication No. 2015 / 145871. Compound M7 was synthesized according to the method described in International Publication No. 2013 / 146806. Compound M8 was synthesized according to the method described in Japanese Patent Publication No. 2010-189630.

[0270] [ka]

[0271] <Synthesis Example 2> Synthesis of polymer compounds HTL-P1~HTL-P3 and HTL-PC1 The polymer compounds (copolymers) HTL-P1 to HTL-P3 and HTL-PC1 were synthesized using the types and molar ratios of compounds listed in Table 2, and the synthesis method described in the same table. The Mn and Mw of the obtained polymer compounds are as shown in Table 2.

[0272] [Table 2]

[0273] <Compounds HTL-M1 and HTL-M2> Compounds HTL-M1 and HTL-M2 were manufactured by Luminescence Technology.

[0274] [ka]

[0275] <Synthesis Example 3> Synthesis and acquisition of compounds B1-B3 Compound B1 was sourced from Luminescence Technology. Compound B2 was synthesized according to the method described in Angew. Chem. Int. Ed. 2020, 59, 17442-17446. Compound B3 was synthesized according to the method described in Angew. Chem. Int. Ed. 2020, 59, 17499-17503.

[0276] [ka]

[0277] <Synthesis Example 4> Synthesis and acquisition of compounds T1-T10 and TC1 Compounds T1-T8 and TC1 were sourced from Luminescence Technology. Compound T9 was synthesized according to the method described in Organic Electronics 2017, 46, 105-144. Compound T10 was synthesized according to the method described in Japanese Patent Publication No. 2019-501513.

[0278] [ka]

[0279] <Example D1> Fabrication and evaluation of light-emitting element D1 (Formation of anode and hole injection layer) An anode was formed by depositing an ITO film to a thickness of 45 nm onto a glass substrate using the sputtering method. On this anode, ND-3202 (manufactured by Nissan Chemical Corporation), a hole injection material, was sputtered. A 65 nm thick film was deposited using the coating method, and a hole injection layer was formed by heating it on a hot plate at 240°C for 10 minutes in an atmospheric environment.

[0280] (Formation of the second layer) The polymer compound HTL-P1 was dissolved in xylene at a concentration of 0.8% by mass. Using the resulting xylene solution, a 20 nm thick film was deposited on the hole-injection layer by spin coating. A second layer was formed by heating the film on a hot plate at 200°C for 30 minutes under a nitrogen gas atmosphere. This heating caused the polymer compound HTL-P1 to become a crosslinked material.

[0281] (Formation of the first layer) Compounds T1, T2, and B1 (compound T1 / compound T2 / compound B1 = 49% by mass / 48% by mass / 3% 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.

[0282] (Formation of cathode) The substrate on which the first layer has been formed is deposited in the vapor deposition machine, 1.0 × 10 -4After 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.

[0283] (Evaluation of light-emitting elements) EL emission was observed when a voltage was applied to the light-emitting element D1. The emission level of the light-emitting element D1 was 10 cd / m². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0284] <Examples D2, D3, Comparative Examples CD1 and CD2> Fabrication and Evaluation of Light-Emitting Devices D2, D3, 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, D3, 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, D3, CD1, and CD2. The 10 cd / m³ light emission of light-emitting elements D2, D3, CD1, and CD2. 2 The drive voltage and CIE chromaticity coordinates were measured.

[0285] The results for Examples D1-D3 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-D3 and CD2 relative to the drive voltage [V] of light-emitting element CD1.

[0286] [Table 3]

[0287] <Example D4, Comparative Examples CD3 and CD4> Fabrication and Evaluation of Light-Emitting Devices D4, CD3 and CD4 In Example D1, except that in (formation of the second layer) "polymer compound HTL-P1 dissolved in xylene at a concentration of 0.8 mass%" was replaced with "polymer compound HTL-P2 dissolved in xylene at a concentration of 0.6 mass%", and in (formation of the first layer) the materials and material ratios listed in Table 4 were used, light-emitting elements D4, CD3, 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 D4, CD3, and CD4. The 100 cd / m³ light emission values ​​for light-emitting elements D4, CD3, and CD4 were obtained. 2 The drive voltage and CIE chromaticity coordinates were measured.

[0288] The results for Example D4, Comparative Examples CD3 and CD4 are shown in Table 4. In Table 4, the drive voltage difference [V] refers to the difference in drive voltage [V] of light-emitting elements D4 and CD3 relative to the drive voltage [V] of light-emitting element CD4.

[0289] [Table 4]

[0290] <Example D5 and Comparative Example CD5> Fabrication and Evaluation of Light-Emitting Devices D5 and CD5 Except for using the materials and material ratios listed in Table 5 for the (formation of the second layer) and (formation of the first layer) of Example D4, light-emitting elements D5 and CD5 were fabricated in the same manner as in Example D4. EL emission was observed when a voltage was applied to light-emitting elements D5 and CD5. The emission level of light-emitting elements D5 and CD5 was 30 cd / m². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0291] The results for Example D5 and Comparative Example CD5 are shown in Table 5. In Table 5, the drive voltage difference [V] refers to the difference in the drive voltage [V] of light-emitting element D5 relative to the drive voltage [V] of light-emitting element CD5.

[0292] [Table 5]

[0293] <Examples D6 and D7> Fabrication and evaluation of light-emitting elements D6 and D7 Except for using the materials and material ratios listed in Table 6 for the (formation of the second layer) and (formation of the first layer) of Example D4, light-emitting elements D6 and D7 were fabricated in the same manner as in Example D4. EL emission was observed when a voltage was applied to light-emitting elements D6 and D7. Optical elements D6 and D7: 20 cd / m² 2 The drive voltage and CIE chromaticity coordinates were measured.

[0294] The results for Examples D6 and D7 are shown in Table 6. In Table 6, the drive voltage difference [V] refers to the difference between the drive voltage [V] of light-emitting element D6 and the drive voltage [V] of light-emitting element D7.

[0295] [Table 6]

[0296] <Examples D8 and D9> Fabrication and evaluation of light-emitting elements D8 and D9 Except for using the materials and material ratios listed in Table 7 for the (formation of the second layer) and (formation of the first layer) of Example D4, light-emitting elements D8 and D9 were fabricated in the same manner as in Example D4. EL emission was observed when a voltage was applied to light-emitting elements D8 and D9. The emission of light-emitting elements D8 and D9 was 50 cd / m². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0297] The results for Examples D8 and D9 are shown in Table 7. In Table 7, the drive voltage difference [V] refers to the difference between the drive voltage [V] of light-emitting element D8 and the drive voltage [V] of light-emitting element D9.

[0298] [Table 7]

[0299] <Example D10, Comparative Examples CD6 and CD7> Fabrication and Evaluation of Light-Emitting Devices D10, CD6 and CD7 Except for using the materials and material ratios listed in Table 8 for the (formation of the second layer) and (formation of the first layer) of Example D4, the light-emitting elements D10, CD6, and CD7 were fabricated in the same manner as in Example D4. EL emission was observed when a voltage was applied to the light-emitting elements D10, CD6, and CD7. The light-emitting elements D10, CD6, and CD7 had a light emission of 30 cd / m². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0300] The results for Example D10 and Comparative Examples CD6 and CD7 are shown in Table 8. In Table 8, the drive voltage difference [V] refers to the difference in drive voltage [V] of light-emitting elements D10 and CD6 relative to the drive voltage [V] of light-emitting element CD7.

[0301] [Table 8]

[0302] <Examples D11 and D12> Fabrication and evaluation of light-emitting elements D11 and D12 Except for using the materials and material ratios listed in Table 9 for the (formation of the second layer) and (formation of the first layer) of Example D4, light-emitting elements D11 and D12 were fabricated in the same manner as in Example D4. EL emission was observed when a voltage was applied to light-emitting elements D11 and D12. The emission level of light-emitting elements D11 and D12 was 100 cd / m². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0303] The results for Examples D11 and D12 are shown in Table 9. In Table 9, the drive voltage difference [V] refers to the difference between the drive voltage [V] of light-emitting element D11 and the drive voltage [V] of light-emitting element D12.

[0304] [Table 9]

[0305] <Examples D13, D14 and Comparative Example CD8> Fabrication and Evaluation of Light-Emitting Devices D13, D14 and CD8 Except for using the materials and material ratios listed in Table 10 for the (formation of the second layer) and (formation of the first layer) of Example D1, light-emitting elements D13, D14, 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 D13, D14, and CD8. The emission level of light-emitting elements D13, D14, and CD8 was 10 cd / m². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0306] The results for Examples D13, D14 and Comparative Example CD8 are shown in Table 10. In Table 10, the drive voltage difference [V] refers to the difference in the drive voltage [V] of light-emitting elements D13 and D14 relative to the drive voltage [V] of light-emitting element CD8.

[0307] [Table 10]

[0308] <Examples D15, D16 and Comparative Example CD9> Fabrication and Evaluation of Light-Emitting Devices D15, D16 and CD9 Except for using the materials and material ratios listed in Table 11 for (formation of the second layer) and (formation of the first layer) of Example D1, light-emitting elements D15, D16, and CD9 were fabricated in the same manner as in Example D1. EL emission was observed when a voltage was applied to light-emitting elements D15, D16, and CD9. The emission level of light-emitting elements D15, D16, and CD9 was 10 cd / m². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0309] The results for Examples D15, D16 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 D15 and D16 relative to the drive voltage [V] of light-emitting element CD9.

[0310] [Table 11]

[0311] <Examples D17 and D18> Fabrication and evaluation of light-emitting elements D17 and D18 Except for using the materials and material ratios listed in Table 12 for the (formation of the second layer) and (formation of the first layer) of Example D1, light-emitting elements D17 and D18 were fabricated in the same manner as in Example D1. EL emission was observed when a voltage was applied to light-emitting elements D17 and D18. The emission level of light-emitting elements D17 and D18 was 10 cd / m². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0312] The results for Examples D17 and D18 are shown in Table 12. In Table 12, the drive voltage difference [V] refers to the difference between the drive voltage [V] of light-emitting element D17 and the drive voltage [V] of light-emitting element D18.

[0313] [Table 12]

[0314] <Example D19 and Comparative Example CD10> Fabrication and Evaluation of Light-Emitting Devices D19 and CD10 Except for using the materials and material ratios listed in Table 13 for (formation of the second layer) and (formation of the first layer) in Example D4, the light-emitting elements D19 and CD10 were fabricated in the same manner as in Example D4. EL emission was observed when a voltage was applied to the light-emitting elements D19 and CD10. The light-emitting elements D19 and CD10 had a light emission of 10 cd / m². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0315] <Example D20> Fabrication and evaluation of light-emitting element D20 Except for using the materials and material ratios listed in Table 13 for the (formation of the second layer) and (formation of the first layer) of Example D1, the light-emitting element D20 was fabricated in the same manner as in Example D1. EL emission was observed when a voltage was applied to the light-emitting element D20. The light-emitting element D20 had a emission of 10 cd / m². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0316] The results for Examples D19, D20 and Comparative Example CD10 are shown in Table 13. In Table 13, the drive voltage difference [V] refers to the difference in drive voltage [V] of light-emitting elements D19 and D20 relative to the drive voltage [V] of light-emitting element CD10.

[0317] [Table 13]

[0318] <Example D21 and Comparative Example CD11> Fabrication and evaluation of light-emitting elements D21 and CD11 Except for using the materials and material ratios listed in Table 14 for (formation of the second layer) and (formation of the first layer) in Example D4, the light-emitting elements D21 and CD11 were fabricated in the same manner as in Example D4. EL emission was observed when a voltage was applied to the light-emitting elements D21 and CD11. The light-emitting elements D21 and CD11 had a light emission of 20 cd / m². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0319] The results for Example D21 and Comparative Example CD11 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 D21 and the drive voltage [V] of the light-emitting element CD11.

[0320] [Table 14]

[0321] <Example D22 and Comparative Example CD12> Fabrication and evaluation of light-emitting elements D22 and CD12 Except for using the materials and material ratios listed in Table 15 for the (formation of the second layer) and (formation of the first layer) of Example D4, the light-emitting elements D22 and CD12 were fabricated in the same manner as in Example D4. EL emission was observed when a voltage was applied to the light-emitting elements D22 and CD12. The light-emitting elements D22 and CD12 had an emission of 10 cd / m². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0322] The results for Example D22 and Comparative Example CD12 are shown in Table 15. In Table 15, the drive voltage difference [V] refers to the difference in the drive voltage [V] of the light-emitting element D22 with respect to the drive voltage [V] of the light-emitting element CD12.

[0323] [Table 15]

[0324] <Example D23 and Comparative Example CD13> Fabrication and evaluation of light-emitting elements D23 and CD13 Except for using the materials and material ratios listed in Table 16 for the (formation of the second layer) and (formation of the first layer) of Example D4, the light-emitting elements D23 and CD13 were fabricated in the same manner as in Example D4. EL emission was observed when a voltage was applied to the light-emitting elements D23 and CD13. The light-emitting elements D23 and CD13 had an emission of 3000 cd / m². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0325] The results for Example D23 and Comparative Example CD13 are shown in Table 16. In Table 16, the drive voltage difference [V] refers to the difference between the drive voltage [V] of the light-emitting element D23 and the drive voltage [V] of the light-emitting element CD13.

[0326] [Table 16]

[0327] <Example D24> Fabrication and evaluation of light-emitting element D24 (Formation of anode and hole injection layer) An anode was formed by depositing an ITO film to a thickness of 45 nm onto a glass substrate using the sputtering method. On this anode, a hole injection material, ND-3202 (manufactured by Nissan Chemical Corporation), was deposited to a thickness of 65 nm using the spin coating method, and a hole injection layer was formed by heating it on a hot plate at 240°C for 15 minutes in an atmospheric environment.

[0328] (Formation of the second layer) The polymer compound HTL-P2 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-P2 to become a crosslinked material.

[0329] (Formation of the first layer) Compounds T4, T3, and B2 (compound T4 / compound T3 / compound B2 = 48.5% by mass / 48.5% by mass / 3% 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 130°C for 10 minutes under a nitrogen gas atmosphere.

[0330] (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 D24.

[0331] (Evaluation of light-emitting elements) EL emission was observed when a voltage was applied to the light-emitting element D24. The light-emitting element D24 had an emission of 2500 cd / m². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0332] <Comparative Examples CD14 and CD15> Fabrication and evaluation of light-emitting elements CD14 and CD15 Except for using the materials and material ratios listed in Table 17 in Example D24 (formation of the first layer), light-emitting elements CD14 and CD15 were fabricated in the same manner as in Example D24. EL emission was observed when a voltage was applied to light-emitting elements CD14 and CD15. The light-emitting elements CD14 and CD15 exhibited an emission of 2500 cd / m². 2The drive voltage and CIE chromaticity coordinates were measured.

[0333] The results for Example D24 and Comparative Examples CD14 and CD15 are shown in Table 17. In Table 17, the drive voltage difference [V] refers to the difference in drive voltage [V] of light-emitting elements D24 and CD15 relative to the drive voltage [V] of light-emitting element CD14.

[0334] [Table 17]

[0335] <Example D25, Comparative Examples CD16 and CD17> Fabrication and Evaluation of Light-Emitting Devices D25, CD16 and CD17 Except for using the materials and material ratios listed in Table 18 in Example D24 (formation of the first layer), light-emitting elements D25, CD16, and CD17 were fabricated in the same manner as in Example D24. EL emission was observed when a voltage was applied to light-emitting elements D25, CD16, and CD17. The emission of EL by light-emitting elements D25, CD16, and CD17 was 2500 cd / m². 2 The drive voltage and CIE chromaticity coordinates were measured.

[0336] The results for Example D25 and Comparative Examples CD16 and CD17 are shown in Table 18. In Table 18, the drive voltage difference [V] refers to the difference in drive voltage [V] of light-emitting elements D25 and CD17 relative to the drive voltage [V] of light-emitting element CD16.

[0337] [Table 18]

[0338] In each of the above examples and comparative examples, compounds T1 to T10 and TC1 were used as host materials. Furthermore, in each of the above examples and comparative examples, compounds B1 to B3 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 compound (B) and two or more compounds represented by formula (T-1), The compound (B) contains a boron atom, an oxygen atom, a sulfur atom, a selenium atom, and sp ３ A compound having a fused heterocyclic skeleton (b) containing at least one atom selected from the group consisting of carbon atoms and nitrogen atoms within the ring, The second layer is a layer containing a crosslinked compound having a crosslinking group, 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 group obtained by removing one or more hydrogen atoms from a pyrimidine, then the light-emitting element comprises two compounds that satisfy requirement (i). (i) 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, 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, the monovalent heterocyclic group contains a nitrogen atom that does not form a double bond within the ring, and within the ring are a group represented by -N-, a group represented by -C(=O)-, a group represented by -S(=O)-, and -S(=O) ２ It is a monovalent heterocyclic group that does not contain the group represented by -. L Ｔ１ represents a divalent group, and the group 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 each is 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. However, Ar Ｔ２ In this context, a heterocyclic group containing a group represented by =N- is either a polycyclic heterocyclic group containing a group represented by =N-, or a monocyclic, six-membered heterocyclic group containing a group represented by =N-. n Ｔ２ represents an integer greater than or equal to 1. However, Ar Ｔ２ is a group represented by -C(=O)-, a group represented by -S(=O)-, or -S(=O) ２ If the group is represented by -, then n Ｔ２ The answer is 2. Ar Ｔ１ and L Ｔ１ It is bonded directly to it, or bonded via a divalent group, to form a ring. That's also good. Ar Ｔ２ and L Ｔ１ Ar may form a ring by directly bonding with or via a divalent group. Ｔ１ and Ar Ｔ２ It may form a ring by directly bonding with or by bonding via a divalent group.

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 ring is a heterocyclic group containing a group represented as =N-, and these groups may have substituents.

6. The light-emitting element according to any one of claims 1 to 5, wherein the condensed heterocyclic skeleton (b) contains a boron atom and at least one atom selected from the group consisting of an oxygen atom, a sulfur atom, and a nitrogen atom within the ring.

7. The light-emitting element according to any one of claims 1 to 5, wherein the compound (B) is a compound represented by formula (1-1), a compound represented by formula (1-2), or a compound represented by formula (1-3). 【Chemistry 2】 [In the formula, Ar １ Ar ２ and Ar ３ Each of these independently represents an aromatic hydrocarbon group or a 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. Y １ represents an oxygen atom, a sulfur atom, a selenium atom, a group represented by -N(Ry)-, an alkylene group, or a cycloalkylene 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. Y ２ and Y ３ These are, independently, a single bond, an oxygen atom, a sulfur atom, a selenium atom, and -N ( This represents a group represented by Ry)-, a group represented by -B(Ry)-, an alkylene group, a cycloalkylene group, 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 each is bonded. Ry represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may have substituents. If there are multiple substituents, they may be the same or different, and they may be bonded to each other, forming a ring with the atom to which each is bonded. If there are multiple Ry groups, they may be the same or different. Y １ and Ar １ This may involve direct bonding or bonding via a divalent group to form a ring. １ and Ar ２ This may involve direct bonding or bonding via a divalent group to form a ring. ２ and Ar １ This may involve direct bonding or bonding via a divalent group to form a ring. ２ and Ar ３ This may involve direct bonding or bonding via a divalent group to form a ring. ３ and Ar ２ This may involve direct bonding or bonding via a divalent group to form a ring. ３ and Ar ３ This may involve direct bonding or bonding via a divalent group to form a ring.

8. The aforementioned Y １ , the aforementioned Y ２ and Y ３ The light-emitting element according to claim 7, wherein each of the groups is independently represented by an oxygen atom, a sulfur atom, or -N(Ry)-.

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

10. The light-emitting element according to any one of claims 1 to 5, 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 any one of claims 1 to 5, wherein the first layer and the second layer are adjacent to each other.

12. The light-emitting element according to any one of claims 1 to 5, wherein the second layer is a layer provided between the anode and the first layer.

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