Light emitting element

Abstract

To provide a light emitting element with excellent external quantum efficiency.SOLUTION: In a light emitting element having an anode, a cathode, and a first layer and a second layer arranged between the anode and the cathode, the first layer contains a specific metal complex and a low-molecular-weight compound composed solely of main-group elements, the second layer contains a crosslinked body of a polymer compound containing constituent units bearing crosslinking groups, and when the total molecular weight of all constituent units forming all polymer compounds contained in the second layer is denoted as X1 and the total number of crosslinking groups possessed by all constituent units forming all polymer compounds contained in the second layer is denoted as Y1, the value of (Y1×1000) / X1 is 0.25 or greater.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a light-emitting device. [Background technology]

[0002] Organic electroluminescent elements (hereinafter also referred to as "light-emitting elements") can be suitably used for displays and lighting applications, and research and development into such elements is being conducted. For example, Patent Document 1 describes a light-emitting element having a hole transport layer formed using a polymer compound (P0) represented by the following formula, and a light-emitting layer containing a metal complex (G0) and a compound (H0).

[0003] [ka] [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special table number 2019-534244 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above-mentioned light-emitting elements do not necessarily have sufficient external quantum efficiency. Therefore, an object of the present invention is to provide a light-emitting device with excellent external quantum efficiency. [Means for solving the problem]

[0006] The present invention provides the following [1] to

[10] .

[0007] [1] A light-emitting device having an anode, a cathode, and a first layer and a second layer provided between the anode and the cathode, the first layer is a layer containing a metal complex represented by formula (1) and a low-molecular-weight compound consisting only of a main group element, the second layer is a layer containing a crosslinked product of a polymer compound including a structural unit having a crosslinking group, A light-emitting device in which the value of (Y1×1000) / X1 is 0.25 or more, where X1 is the total molecular weight of all structural units constituting all of the polymer compounds contained in the second layer, and Y1 is the total number of crosslinking groups possessed by all structural units constituting all of the polymer compounds contained in the second layer. [ka] [In the formula, M represents a rhodium atom, a palladium atom, an iridium atom, or a platinum atom. n 1 represents an integer of 1 or greater, and n 2 represents an integer of 0 or more. However, when M is a rhodium atom or an iridium atom, n 1 +n 2 is 3, and when M is a palladium atom or a platinum atom, n 1 +n 2 is 2. E 1 and E 2 Each of E independently represents a carbon atom or a nitrogen atom. 1 and E 2 When there are a plurality of groups, they may be the same or different. Ring L 1 represents an aromatic heterocycle, and this ring may have a substituent. When a plurality of such substituents are present, 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 bonded. Ring L 1 When there are multiple groups, they may be the same or different. Ring L 2represents a polycyclic aromatic hydrocarbon ring or a polycyclic aromatic heterocycle, and these rings may have a substituent. When a plurality of such substituents are present, 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 bonded. Ring L 2 When there are multiple groups, they may be the same or different. Ring L 1 and Ring L 2 may be bonded directly or via a divalent group to form a ring. However, ring L 1 When is an aromatic heterocycle containing a 5-membered ring, ring L 2 is a polycyclic aromatic hydrocarbon ring or a polycyclic aromatic heterocycle containing at least one of a sulfur atom and a nitrogen atom in the ring. A 1 -G 1 -A 2 represents an anionic bidentate ligand. 1 and A 2 each independently represents a carbon atom, an oxygen atom, or a nitrogen atom, and these atoms may be atoms constituting a ring. 1 is a single bond or A 1 and A 2 A represents an atomic group that, together with A, constitutes a bidentate ligand. 1 -G 1 -A 2 When there are multiple, they may be the same or different. [2] The light-emitting device according to [1], wherein the metal complex represented by the formula (1) is a metal complex represented by the formula (1-A). [ka] [In the formula, M, n 1 , n 2 , E 1 , E 2 , ring L 1 , and A 1 -G 1 -A 2 represents the same meaning as above. Ring R B1 and ring R B2 Each independently represents an aromatic hydrocarbon ring or an aromatic heterocyclic ring, and these rings may have a substituent. When a plurality of such substituents are present, 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 bonded. Ring R B1 and ring R B2 When there are a plurality of groups, they may be the same or different. Ring L 1 and ring R B1 may be bonded directly or via a divalent group to form a ring. X a and X b Each of X independently represents a direct bond or a divalent group, and the group may have a substituent. When a plurality of the substituents is present, 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 bonded. a and X b When there are a plurality of groups, they may be the same or different. Ring R B1 and X a and may be bonded directly or via a divalent group to form a ring. B1 and X b and may be bonded directly or via a divalent group to form a ring. B2 and X a and may be bonded directly or via a divalent group to form a ring. B2 and X b may be bonded directly or via a divalent group to form a ring. However, ring L 1 When is an aromatic heterocycle containing a five-membered ring, it satisfies at least one of (i), (ii) and (iii). (i)X a and X b At least one of -S- and / or -N(R Xa’ )-, and the group may have a substituent. (ii) Ring R B1 and ring R B2 At least one of the above is an aromatic heterocycle containing at least one of a sulfur atom and a nitrogen atom in the ring, and the aromatic heterocycle may have a substituent. (iii) Ring R B1 and ring R B2 is an aromatic hydrocarbon ring, and X a and X b are each independently a direct bond or a divalent group, and the divalent group is -C(=O)- and -C(R Xa )2- is a divalent group consisting of at least one selected from the group consisting of The group may have a substituent. R Xa represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, an aryloxy group, a monovalent heterocyclic group, a substituted amino group, or a halogen atom, and these groups may have a substituent. When there are multiple such 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 bonded. When there are multiple R Xa 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 bonded. R Xa’ represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may have a substituent. When a plurality of such substituents are present, 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 bonded. [3] The light-emitting device according to [2], wherein the metal complex represented by formula (1-A) is a metal complex represented by formula (1-A1), formula (1-A2), or formula (1-A3). [ka] [In the formula, M, n 1 , n 2 , ring L 1 , Xa , X b , and A 1 -G 1 -A 2 represents the same meaning as above. R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 and R 12 R each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, an aryloxy group, a monovalent heterocyclic group, a substituted amino group, or a halogen atom, and these groups may have a substituent. 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 and R 12 When there are multiple R, they may be the same or different. 6 and R 7 , R 7 and R 8 , R 8 and R 9 , R 10 and R 11 , R 5 and R 12 , and ring L 1 and the substituents that may be present on R 5 may be bonded to each other to form a ring together with the atoms to which they are bonded. However, ring L 1 is an aromatic heterocycle containing a 5-membered ring, X a and X b are each independently a direct bond or a divalent group, and the divalent group is -S-, -C(=O)-, -C(R Xa )2- and -N(R Xa’ )-, and the group may have a substituent. R Xa and R Xa’ represents the same meaning as above. In formula (1-A1), R 6 and X a , R 9 and X b , and R 10 and X b may be bonded to each other directly or via a divalent group to form a ring together with the atom to which they are bonded. In formula (1-A2), R 5 and X a , R 6 and X a , R 9 and X b , and R 10 and X b may be bonded to each other directly or via a divalent group to form a ring together with the atom to which they are bonded. In formula (1-A3), R 6 and X a , R 9 and X b , and R 12 and X a may be bonded to each other directly or via a divalent group to form a ring together with the atom to which they are bonded. [4] The ring L 1 is a pyridine ring, a diazabenzene ring, an azanaphthalene ring, a diazanaphthalene ring, a diazole ring, or a triazole ring, and these rings may have a substituent. When a plurality of the substituents are present, the substituents 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 bonded. [5] The light-emitting device according to any one of [1] to [4], wherein the structural unit having a crosslinking group is a structural unit represented by formula (Z) or a structural unit represented by formula (Z'). [ka] [In the formula, n represents an integer of 1 or more. nA represents an integer equal to or greater than 0. When there are multiple nAs, they may be the same or different. Ar 3 represents a hydrocarbon group, a heterocyclic group, or a group in which at least one hydrocarbon group and at least one heterocyclic group are directly bonded, and these groups may have a substituent. When a plurality of such substituents are present, 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 bonded. L 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 a substituent. When there are multiple such 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 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 a substituent. When there are multiple such 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 bonded. L A When there are multiple groups, they may be the same or different. X represents a crosslinking group. When a plurality of X's are present, they may be the same or different. [ka] [In the formula, mA, m, and c each independently represent an integer of 0 or greater. When a plurality of mA's are present, they may be the same or different. When a plurality of m's are present, 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 a substituent. When a plurality of such substituents are present, 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 bonded. Ar 5When there are multiple groups, they may be the same or different. Ar 4 and Ar 6 each independently represents an arylene group or a divalent heterocyclic group, and these groups may have a substituent. When a plurality of such substituents are present, 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 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 a substituent. When there are multiple such 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 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 a substituent. When there are multiple such 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 bonded. K A When there are multiple groups, they may be the same 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 a substituent. When a plurality of such substituents are present, 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 bonded. When a plurality of X' are present, they may be the same or different. However, at least one X' is a bridging group. [6] The light-emitting device according to any one of [1] to [5], wherein the crosslinking group is a crosslinking group selected from Group A of crosslinking groups. (Bridging group A group) [ka] [In the formula, R XL represents a methylene group, an oxygen atom, or a sulfur atom; n XL represents an integer from 0 to 5. XLWhen there are multiple n, they may be the same or different. XL When there are a plurality of groups, they may be the same or different. *1 indicates the bonding position. These bridging groups may have a substituent, and when there are a plurality of such 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 bonded.] [7] The light-emitting device according to any one of [1] to [6], wherein the low-molecular compound consisting only of a typical element is a compound represented by formula (H-1). [ka] [In the formula, Ar H1 and Ar H2 each independently represents an aryl group or a monovalent heterocyclic group, and these groups may have a substituent. n H1 and n H2 Each independently represents 0 or 1. H1 When there are multiple n's, they may be the same or different. H2 may be the same or different. n H3 represents an integer between 0 and 10. L H1 represents an arylene group, a divalent heterocyclic group, or —[C(R H11 )2]n H11 -, and these groups may have a substituent. H1 When there are multiple n, they may be the same or different. H11 represents an integer between 1 and 10. H11 represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, or a monovalent heterocyclic group, and these groups may have a substituent. H11 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 bonded. L H2is -N(-L H21 -R H21 )-. L H2 When there are multiple L's, they may be the same or different. H21 represents a single bond, an arylene group, or a divalent heterocyclic group, and these groups may have a substituent. H21 is a hydrogen atom , an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may have a substituent.] [8] The light-emitting device according to any one of [1] to [7], wherein the first layer further contains at least one 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. [9] The light-emitting device according to any one of [1] to [8], wherein the first layer and the second layer are adjacent to each other.

[10] The light-emitting device according to any one of [1] to [9], wherein the second layer is a layer provided between the anode and the first layer. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a light-emitting device with excellent external quantum efficiency. DETAILED DESCRIPTION OF THE INVENTION

[0009] Preferred embodiments of the present invention will be described in detail below.

[0010] <Explanation of common terms> Terms commonly used in this specification have the following meanings unless otherwise specified.

[0011] 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.

[0012] "Room temperature" means 25°C. The hydrogen atom may be a deuterium atom or a proton atom. In the formula representing a metal complex, the solid line representing a bond to a central metal means an ionic bond, a covalent bond, or a coordinate bond.

[0013] "Low molecular weight compounds" are compounds that do not have a molecular weight distribution and have a molecular weight of 1 x 10 4 The following compounds are meant:

[0014] "Polymer compounds" are compounds that have a molecular weight distribution and have a number average molecular weight of 1 x 10 in terms of polystyrene. 3 or more (e.g., 1×10 3 ~1×10 8 ) means a polymer in which The term "structural unit" refers to a unit that exists in one or more instances in a polymer compound. A structural unit that exists in two or more instances in a polymer compound is generally also called a "repeating unit." The polymer compound may be any of a block copolymer, a random copolymer, an alternating copolymer, a graft copolymer, or other forms. The terminal group of the polymer compound is preferably a stable group, since if the polymerization active group remains as it is, the light-emitting properties etc. may be deteriorated when the polymer compound is used to produce a light-emitting device. The terminal group of the polymer compound is preferably a group that is conjugated to the main chain of the polymer compound, and examples thereof include an aryl group or a monovalent heterocyclic group that is bonded to the main chain of the polymer compound via a carbon-carbon bond.

[0015] The "alkyl group" may be either linear or branched. The number of carbon atoms in a linear alkyl group, not including the number of carbon atoms in the substituent, is usually 1 to 50, preferably 1 to 20, and more preferably 1 to 10. The number of carbon atoms in a branched alkyl group, not including the number of carbon atoms in the substituent, is usually 3 to 50, preferably 3 to 20, and more preferably 4 to 10.

[0016] The alkyl group may have a substituent. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a 2-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isoamyl group, a 2-ethylbutyl group, a hexyl group, a heptyl group, an octyl group, a 2-ethylhexyl group, a 3-propylheptyl group, a decyl group, a 3,7-dimethyloctyl group, a 2-ethyloctyl group, a 2-hexyldecyl group, and a dodecyl group. The alkyl group may also be a group in which some or all of the hydrogen atoms in these groups have been substituted with a substituent (for example, a trifluoromethyl group, a pentafluoroethyl group, a perfluorobutyl group, a perfluorohexyl group, a perfluorooctyl group, a 3-phenylpropyl group, a 3-(4-methylphenyl)propyl group, a 3-(3,5-di-hexylphenyl)propyl group, and a 6-ethyloxyhexyl group).

[0017] The number of carbon atoms in the "cycloalkyl 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 substituent. The cycloalkyl group may have a substituent. Examples of the cycloalkyl group include a cyclohexyl group, a cyclohexylmethyl group, a cyclohexylethyl group, and groups in which some or all of the hydrogen atoms in these groups have been substituted with substituents.

[0018] The number of carbon atoms in the "alkylene 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 substituent. The alkylene group may have a substituent. Examples of the alkylene group include a methylene group, an ethylene group, a propylene group, a butylene group, a hexylene group, an octylene group, and groups in which some or all of the hydrogen atoms in these groups have been substituted with substituents.

[0019] The number of carbon atoms in the "cycloalkylene group" is usually 3 to 50, preferably 4 to 20, and more preferably 5 to 10, not including the number of carbon atoms in the substituent. The cycloalkylene group may have a substituent. Examples of the cycloalkylene group include a cyclohexylene group and groups in which some or all of the hydrogen atoms in the cyclohexylene group have been substituted with substituents.

[0020] An "aromatic hydrocarbon group" refers to a group obtained by removing one or more hydrogen atoms directly bonded to carbon atoms constituting an aromatic hydrocarbon ring. A group obtained by removing one hydrogen atom directly bonded to a carbon atom constituting the ring from an aromatic hydrocarbon ring is also called an "aryl group." A group obtained by removing two hydrogen atoms directly bonded to carbon atoms constituting the ring from an aromatic hydrocarbon ring is also called an "arylene group." The number of carbon atoms in the aromatic hydrocarbon group is usually 6 to 60, preferably 6 to 40, and more preferably 6 to 20, not including the number of carbon atoms in the substituent.

[0021] Examples of the "aromatic hydrocarbon group" include groups in which one or more hydrogen atoms directly bonded to carbon atoms constituting the ring have been removed from a monocyclic aromatic hydrocarbon ring (such as benzene) or a polycyclic aromatic hydrocarbon ring (such as bicyclic aromatic hydrocarbon rings such as naphthalene, indene, naphthoquinone, indenone, and tetralone; tricyclic aromatic hydrocarbon rings such as anthracene, phenanthrene, dihydrophenanthrene, fluorene, anthraquinone, phenanthoquinone, and fluorenone; tetracyclic aromatic hydrocarbon rings such as benzanthracene, benzophenanthrene, and benzofluorene; pentacyclic aromatic hydrocarbon rings such as dibenzanthracene, dibenzophenanthrene, dibenzofluorene, indenofluorene, and benzofluoranthene; hexacyclic aromatic hydrocarbon rings such as spirobifluorene; and heptacyclic aromatic hydrocarbon rings such as benzospirobifluorene and acenaphthofluoranthene), and groups in which some or all of the hydrogen atoms in the groups have been substituted with substituents. Aromatic hydrocarbon groups include groups in which multiple of these groups are bonded. The hydrogen hydride group may have a substituent.

[0022] The aryl group may have a substituent. Examples of the aryl group include a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group, a fluorenyl group, a biphenyl group, and groups in which some or all of the hydrogen atoms in these groups have been substituted with substituents. The aryl group also includes groups in which multiple such groups are bonded.

[0023] The arylene group may have a substituent. Examples of the arylene group include a phenylene group, a naphthalenediyl group, an anthracenediyl group, a phenanthrenediyl group, a dihydrophenanthrenediyl group, a naphthacenediyl group, a fluorenediyl group, a pyrenediyl group, a perylenediyl group, a chrysenediyl group, and groups in which some or all of the hydrogen atoms in these groups have been substituted with substituents, and preferred are groups represented by formulas (A-1) to (A-20). The arylene group includes groups in which a plurality of these groups are bonded.

[0024] [ka]

[0025] [ka]

[0026] [ka]

[0027] [ka]

[0028] [Wherein R and R aare each independently a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, an aryloxy group, a monovalent heterocyclic group, a substituted amino group, or a halogen atom, and these groups may have a substituent. When there are multiple 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 bonded. When there are multiple R, 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 bonded. a 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 bonded. a may be bonded to form a ring together with the atoms to which they are attached.

[0029] The "alkoxy group" may be either linear or branched. The number of carbon atoms in a linear alkoxy group, not including the number of carbon atoms in the substituent, 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, not including the number of carbon atoms in the substituent, is usually 3 to 50, preferably 3 to 20, and more preferably 4 to 10. The alkoxy group may have a substituent. Examples of the alkoxy group include a methoxy group, an ethoxy group, an isopropyloxy group, a butyloxy group, a hexyloxy group, a 2-ethylhexyloxy group, a 3,7-dimethyloctyloxy group, a lauryloxy group, and groups in which some or all of the hydrogen atoms in these groups have been substituted with substituents.

[0030] The number of carbon atoms in the "cycloalkoxy 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 substituent. The cycloalkoxy group may have a substituent. Examples of the cycloalkoxy group include a cyclohexyloxy group and groups in which some or all of the hydrogen atoms in the cycloalkoxy group have been substituted with substituents.

[0031] The number of carbon atoms in the "aryloxy group" is usually 6 to 60, preferably 6 to 40, and more preferably 6 to 20, not including the number of carbon atoms in the substituent. The aryloxy group may have a substituent. Examples of the aryloxy group include a phenoxy group, a naphthyloxy group, an anthracenyloxy group, a pyrenyloxy group, and groups in which some or all of the hydrogen atoms in these groups have been substituted with substituents.

[0032] A "heterocyclic group" refers to a group obtained by removing, from a heterocycle, one or more hydrogen atoms directly bonded to atoms constituting the ring (carbon atoms or heteroatoms). Among heterocyclic groups, an "aromatic heterocyclic group", which is a group obtained by removing, from an aromatic heterocycle, one or more hydrogen atoms directly bonded to atoms constituting the ring, is preferred. A group obtained by removing, from a heterocycle, p hydrogen atoms (p represents an integer of 1 or more) directly bonded to atoms constituting the ring is also called a "p-valent heterocyclic group". A group obtained by removing, from an aromatic heterocycle, p hydrogen atoms directly bonded to atoms constituting the ring is also called a "p-valent aromatic heterocyclic group".

[0033] Examples of the "aromatic heterocycle" include heterocycles that themselves exhibit aromaticity, such as azole, thiophene, furan, pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, and carbazole, as well as heterocycles in which an aromatic ring is condensed with a heterocycle that itself does not exhibit aromaticity, such as phenoxazine, phenothiazine, and benzopyran.

[0034] The number of carbon atoms in the heterocyclic group, not including the number of carbon atoms in the substituent, is usually 1 to 60, preferably 2 to 40, and more preferably 3 to 20. The number of heteroatoms in the heterocyclic group, not including the number of heteroatoms in the substituent, is usually 1 to 30, preferably 1 to 10, more preferably 1 to 5, and even more preferably 1 to 3.

[0035] Examples of the heterocyclic group include monocyclic heterocycles (e.g., furan, thiophene, oxadiazole, thiadiazole, pyrrole, diazole, triazole, tetrazole, pyridine, diazabenzene, and triazine), and polycyclic heterocycles (e.g., bicyclic heterocycles such as azanaphthalene, diazanaphthalene, benzofuran, benzothiophene, indole, azaindole, diazaindole, benzodiazole, benzothiadiazole, benzotriazole, benzothiophene dioxide, benzothiophene oxide, and benzopyranone; dibenzofuran, dibenzothiophene, dibenzothiophene dioxide, dibenzothiophene oxide, dibenzopyranone, dibenzoborole, dibenzosilole, dibenzophosphole, dibenzoselenophene, carbazole, azacarbazole, diazacarbazole, phenoxazine, phenothiazine, 9,10-dihydroacridine, 5,10-dihydrophenazine, acridone, phenazapyridine ... Tricyclic heterocycles such as borine, phenophosphazine, phenoselenazine, phenazasiline, azaanthracene, diazaanthracene, azaphenanthrene, and diazaphenanthrene; tetracyclic heterocycles such as hexaazatriphenylene, benzocarbazole, azabenzocarbazole, diazabenzocarbazole, benzonaphthofuran, and benzonaphthothiophene; dibenzocarbazole, indolocarbazole, indenocarbazole, azaindolocarbazole, diazaindolocarbazole, and the like. Examples of heterocyclic groups include pentacyclic heterocycles such as carbazole, azaindenocarbazole, and diazaindenocarbazole; hexacyclic heterocycles such as carbazolocarbazole, benzoindolocarbazole, and benzoindenocarbazole; and heptacyclic heterocycles such as dibenzoindolocarbazole and dibenzoindenocarbazole. Examples of heterocyclic groups include groups in which one or more hydrogen atoms directly bonded to atoms constituting the ring have been removed from the above heterocyclic groups, and groups in which some or all of the hydrogen atoms in the above groups have been substituted with substituents. Heterocyclic groups include groups in which multiple such groups are bonded. The heterocyclic group may have a substituent.

[0036] The monovalent heterocyclic group may have a substituent. Examples of the monovalent heterocyclic group include a thienyl group, a pyrrolyl group, a furyl group, a pyridyl group, a piperidinyl group, a quinolinyl group, an isoquinolinyl group, a pyrimidinyl group, a triazinyl group, and groups in which some or all of the hydrogen atoms in these groups have been substituted with substituents. The monovalent heterocyclic group also includes groups in which a plurality of these groups are bonded.

[0037] The divalent heterocyclic group may have a substituent. Examples of the divalent heterocyclic group include divalent groups obtained by removing two hydrogen atoms from the carbon atoms or hetero atoms that constitute the ring of pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, carbazole, dibenzofuran, dibenzothiophene, dibenzosilole, phenoxazine, phenothiazine, acridine, dihydroacridine, furan, thiophene, azole, diazole, and triazole, and groups in which some or all of the hydrogen atoms in the group have been substituted with substituents, and preferably groups represented by formulae (AA-1) to (AA-34). The divalent heterocyclic group includes groups in which a plurality of these groups are bonded.

[0038] [ka]

[0039] [ka]

[0040] [ka]

[0041] [ka]

[0042] [ka]

[0043] [ka]

[0044] [ka]

[0045] [Wherein R and R a has the same meaning as above.]

[0046] The term "halogen atom" refers to a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom.

[0047] The "amino group" may have a substituent, and is preferably a substituted amino group (i.e., a secondary amino group or a tertiary amino group, more preferably a tertiary amino group). The substituent that the amino group has is preferably an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may further have a substituent. When the amino group has multiple substituents, they may be the same or different, and may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded. The substituted amino group may further have a substituent. Examples of the substituted amino group include a dialkylamino group, a dicycloalkylamino group, a diarylamino group, and groups in which some or all of the hydrogen atoms in these groups have been substituted with substituents. Examples of the substituted amino group include a dimethylamino group, a diethylamino group, a diphenylamino group, a bis(4-methylphenyl)amino group, a bis(4-tert-butylphenyl)amino group, a bis(3,5-di-tert-butylphenyl)amino group, and groups in which some or all of the hydrogen atoms in these groups have been substituted with substituents.

[0048] The "alkenyl group" may be either linear or branched. The number of carbon atoms in a linear alkenyl group, not including the number of carbon atoms in 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, not including the number of carbon atoms in substituents, is usually 3 to 50, preferably 3 to 20, and more preferably 4 to 10.

[0049] The number of carbon atoms in the "cycloalkenyl group" is usually 3 to 50, preferably 4 to 20, and more preferably 5 to 10, not including the number of carbon atoms in substituents.

[0050] The alkenyl group and cycloalkenyl group may have a substituent. Examples of the alkenyl group include vinyl group, 1-propenyl group, 2-propenyl group, 2-butenyl group, 3-butenyl group, 3-pentenyl group, 4-pentenyl group, 1-hexenyl group, 5-hexenyl group, 7-octenyl group, and groups in which some or all of the hydrogen atoms are substituted. Examples of cycloalkenyl groups include cyclohexenyl groups, cyclohexadienyl groups, cyclooctatrienyl groups, norbornylenyl groups, and groups in which some or all of the hydrogen atoms in these groups have been substituted with substituents.

[0051] The "alkynyl group" may be either linear or branched. The number of carbon atoms in the alkynyl group, not including the carbon atoms of the substituents, is usually 2 to 50, preferably 2 to 20, and more preferably 3 to 10. The number of carbon atoms in a branched alkynyl group, not including the carbon atoms of the substituents, is usually 4 to 50, preferably 4 to 20, and more preferably 4 to 10.

[0052] The number of carbon atoms in the "cycloalkynyl group" is usually 4 to 50, preferably 5 to 20, and more preferably 6 to 10, not including the carbon atoms of the substituents. The alkynyl group and the cycloalkynyl group may have a substituent. Examples of the alkynyl group include an ethynyl group, a 1-propynyl group, a 2-propynyl group, a 2-butynyl group, a 3-butynyl group, a 3-pentynyl group, a 4-pentynyl group, a 1-hexynyl group, a 5-hexynyl group, and groups in which some or all of the hydrogen atoms in these groups have been substituted with a substituent. Examples of the cycloalkynyl group include a cyclooctynyl group and groups in which some or all of the hydrogen atoms in these groups have been substituted with a substituent.

[0053] The "crosslinking group" is a group that can generate a new bond by being subjected to heat treatment, ultraviolet irradiation treatment, near-ultraviolet irradiation treatment, visible light irradiation treatment, infrared irradiation treatment, radical reaction, etc. The crosslinking group is preferably at least one crosslinking group selected from Group A of crosslinking groups (i.e., at least one group selected from the groups represented by Formulae (XL-1) to (XL-19)).

[0054] Examples of the "substituent" include a halogen atom, a cyano group, an alkyl group, a cycloalkyl group, an aryl group, a monovalent heterocyclic group, an alkoxy group, a cycloalkoxy group, an aryloxy group, an amino group, a substituted amino group, an alkenyl group, a cycloalkenyl group, an alkynyl group, or a cycloalkynyl group. The substituent may be a bridging group. When multiple substituents are present, they may be the same or different. When multiple substituents are present, they may be bonded to each other to form a ring together with the atoms to which they are bonded, but it is preferable that they do not form a ring.

[0055] Examples of the "divalent group" include an alkylene group, a cycloalkylene group, an arylene group, a divalent heterocyclic group, -N(R 0 )-, -B(R 0 )-, a group represented by -P(R 0 )-, a group represented by -(O=)P(R 0)-, a group represented by -O-, a group represented by -S-, a group represented by -Se-, a group represented by -S(=O)-, a group represented by -S(=O)2-, and a group represented by -C(=O)-. Divalent groups include groups in which a plurality of these groups are bonded. The divalent group may have a substituent. When a plurality of the substituents are present, 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 bonded. R 0 represents a hydrogen atom or a substituent. R 0 Examples of the substituent include a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, an aryloxy group, a monovalent heterocyclic group, a substituted amino group, a halogen atom, and a cyano group, and are preferably a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may have a substituent. When a plurality of the substituents are present, 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 bonded.

[0056] In this specification, the energy levels of the lowest excited singlet state (S1) and the lowest excited triplet state (T1) of a compound are determined by the following method. First, the density functional at the B3LYP level is used. The ground state of the compound is optimized using the 6-31G* basis function. The resulting optimized structure is then used to calculate the lowest excited singlet state (S1) and lowest excited triplet state (T1) of the compound using a time-dependent density functional method at the B3LYP level. However, if the compound contains atoms for which 6-31G* cannot be used, LANL2DZ is used for those atoms. The quantum chemistry calculation program used for the calculations is Gaussian.

[0057] <First layer> In the light-emitting device of this embodiment, the first layer is a layer containing a metal complex represented by formula (1) and a low-molecular compound consisting only of a main group element. The first layer may contain one or more types of metal complexes represented by formula (1). The first layer may contain one or more types of low molecular weight compounds consisting only of main group elements.

[0058] The total content of the metal complex represented by formula (1) and the low-molecular-weight compound consisting only of a typical element in the first layer may be within a range that allows the first layer to function. The total content of the metal complex represented by formula (1) and the low-molecular-weight compound consisting only of a typical element in the first layer may be, for example, 1 to 100% by mass based on the total amount of the first layer, and is preferably 10 to 100% by mass, more preferably 30 to 100% by mass, even more preferably 50 to 100% by mass, particularly preferably 70 to 100% by mass, and especially preferably 90 to 100% by mass, because this provides a more excellent external quantum efficiency for the light-emitting device of this embodiment. The respective contents of the metal complex represented by formula (1) and the low-molecular-weight compound consisting only of a typical element in the first layer may be within a range that allows the first layer to function. The content of the metal complex represented by formula (1) in the first layer may be, for example, 0.01 to 99 parts by mass, where the total content of the metal complex represented by formula (1) and the low-molecular-weight compound consisting only of a typical element is taken as 100 parts by mass. In order to improve the external quantum efficiency of the light-emitting device of this embodiment, the content is preferably 0.1 to 90 parts by mass, more preferably 0.5 to 70 parts by mass, even more preferably 1 to 50 parts by mass, particularly preferably 3 to 30 parts by mass, and particularly preferably 5 to 20 parts by mass.

[0059] In the first layer, the metal complex represented by formula (1) preferably interacts physically, chemically, or electrically with the low-molecular-weight compound consisting only of a main group element, and this interaction can improve or adjust, for example, the light-emitting properties, charge transport properties, or charge injection properties of the light-emitting device of this embodiment.

[0060] In the light-emitting element of this embodiment, taking the light-emitting material as an example, the metal complex represented by formula (1) and a low-molecular-weight compound consisting only of typical elements electrically interact with each other, and electrical energy is efficiently transferred from the low-molecular-weight compound consisting only of typical elements to the metal complex represented by formula (1), which allows the metal complex represented by formula (1) to emit light more efficiently, and the external quantum efficiency of the light-emitting element of this embodiment is superior. From the above viewpoints, in the first layer, the low molecular weight compound consisting only of main group elements preferably has at least one function selected from hole injection property, hole transport property, electron injection property, and electron transport property, since this leads to a more excellent external quantum efficiency of the light-emitting device of this embodiment. From the above viewpoint, taking the light-emitting material in the first layer as an example, it is preferable that the metal complex represented by formula (1) has light-emitting properties, since the external quantum efficiency of the light-emitting element of this embodiment is superior. From the above viewpoint, in the first layer, the lowest excited singlet state (S1) of the low-molecular-weight compound consisting only of main group elements preferably has a higher energy level than the lowest excited singlet state (S1) of the metal complex represented by formula (1), since this results in a better external quantum efficiency of the light-emitting element of this embodiment. From the above viewpoint, in the first layer, the lowest excited triplet state (T1) of the low-molecular-weight compound consisting only of main group elements preferably has an energy level higher than that of the lowest excited triplet state (T1) of the metal complex represented by formula (1), since this results in a superior external quantum efficiency of the light-emitting element of this embodiment.

[0061] Since the light-emitting device of this embodiment can be fabricated by a wet process, the low-molecular-weight compound consisting only of a typical element is preferably one that is soluble in a solvent capable of dissolving the metal complex represented by formula (1).

[0062] Since the external quantum efficiency of the light-emitting device of this embodiment is superior, the first layer is preferably 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 of host materials. 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 of guest materials.

[0063] In the light-emitting device of this embodiment, when the first layer is a layer containing a host material and a guest material, the total content of the host material and the guest material in the first layer may be within a range that allows the first layer to function. In the light-emitting device of this embodiment, when the first layer is a layer containing a host material and a guest material, the total content of the host material and the guest material in the first layer may be, for example, 1 to 100 mass% based on the total amount of the first layer, and is preferably 10 to 100 mass%, more preferably 30 to 100 mass%, even more preferably 50 to 100 mass%, particularly preferably 70 to 100 mass%, and particularly preferably 90 to 100 mass%, because this provides a more excellent external quantum efficiency for the light-emitting device of this embodiment.

[0064] In the light-emitting device of this embodiment, when the first layer is a layer containing a host material and a guest material, the contents of the host material and the guest material in the first layer may be within ranges that allow the first layer to function. In the light-emitting device of this embodiment, when 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, where the total content of the host material and the guest material is 100 parts by mass. In order to improve the external quantum efficiency of the light-emitting device of this embodiment, the content is preferably 0.1 to 90 parts by mass, more preferably 0.5 to 70 parts by mass, even more preferably 1 to 50 parts by mass, particularly preferably 3 to 30 parts by mass, and particularly preferably 5 to 20 parts by mass.

[0065] In the light-emitting device of this embodiment, when the first layer is a layer containing a host material and a guest material, a low-molecular-weight compound consisting only of a main group element in the first layer is preferably a host material or a guest material, more preferably a host material, because the external quantum efficiency of the light-emitting device of this embodiment is superior. In the light-emitting element of this embodiment, when the first layer is a layer containing a host material and a guest material, the metal complex represented by formula (1) in the first layer is preferably a host material or a guest material, more preferably a guest material, because the external quantum efficiency of the light-emitting element of this embodiment is more excellent.

[0066] In the light-emitting device of this embodiment, the host material refers to a material that interacts physically, chemically, or electrically with the guest material. This interaction can improve or adjust, for example, the light-emitting properties, charge transport properties, or charge injection properties of the light-emitting device of this embodiment. In the light-emitting element of this embodiment, the host material and the guest material electrically interact with each other to efficiently transfer electrical energy from the host material to the guest material. By doing so, the guest material can emit light more efficiently, and the external quantum efficiency of the light-emitting device of this embodiment is more excellent. From the above viewpoint, in the light-emitting element of this embodiment, the host material preferably has at least one function selected from a hole injection property, a hole transport property, an electron injection property, and an electron transport property, since the external quantum efficiency of the light-emitting element of this embodiment is superior. From the above viewpoint, in the light-emitting element of this embodiment, taking the light-emitting material as an example, it is preferable that the guest material has luminescence properties, since this provides a better external quantum efficiency for the light-emitting element of this embodiment. 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 has a higher energy level than the lowest excited triplet state (T1) of the guest material, since this results in a better external quantum efficiency of the light-emitting element of this embodiment. 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 has a higher energy level than the lowest excited singlet state (S1) of the guest material, since this results in a superior external quantum efficiency of the light-emitting element of this embodiment.

[0067] In the light-emitting element of this embodiment, when 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 fabricated by a wet method.

[0068] [Metal complex represented by formula (1)] The metal complex represented by formula (1) is preferably a metal complex that exhibits phosphorescence at room temperature, and more preferably a metal complex that exhibits luminescence from an excited triplet state at room temperature. The molecular weight of the metal complex represented by formula (1) is preferably 3×10 2 ~1×10 4 and more preferably 5×10 2 ~7×10 3 and more preferably 7×10 2 ~5×10 3 and particularly preferably 1 × 10 3 ~3×10 3 is.

[0069] M is preferably an iridium atom or a platinum atom, and more preferably an iridium atom, since the external quantum efficiency of the light-emitting device of this embodiment is superior. When M is a rhodium atom or an iridium atom, n 1 is preferably 2 or 3, and more preferably 3. When M is a palladium atom or a platinum atom, n 1 is preferably 2.

[0070] The metal complex represented by formula (1) can be easily synthesized, so E 1 and E 2 Preferably, at least one of E is a carbon atom,1 and E 2 More preferably, is a carbon atom. The metal complex represented by formula (1) can be easily synthesized, so E 1 and E 2 are preferably the same. In addition, since the metal complex represented by formula (1) can be easily synthesized, E 1 When a plurality of E are present, they are preferably the same. In addition, since the metal complex represented by formula (1) can be easily synthesized, E 2 When there are multiple, they are preferably the same.

[0071] Ring L 1 The number of carbon atoms in the aromatic heterocycle in the formula (I) is usually 1 to 60, preferably 2 to 30, more preferably 3 to 20, still more preferably 4 to 10, and particularly preferably 4 to 5, not including the number of carbon atoms in the substituent. 1 The number of heteroatoms in the aromatic heterocycle in the formula (I) is usually 1 to 30, preferably 1 to 10, more preferably 1 to 5, still more preferably 1 to 3, and particularly preferably 1, not including the number of heteroatoms in the substituents. 1 The number of nitrogen atoms in the aromatic heterocycle is usually 1 to 30, preferably 1 to 10, more preferably 1 to 5, still more preferably 1 to 3, and particularly preferably 1, not including the number of nitrogen atoms in the substituent.

[0072] Ring L 1 Examples of the aromatic heterocycle in the above formula include aromatic heterocycles containing one or more nitrogen atoms in the ring, among the aromatic heterocycles exemplified in the section on heterocyclic groups. The ring may have a substituent.

[0073] Ring L 1 is preferably an aromatic heterocycle containing one or more nitrogen atoms in the ring and a 5- or 6-membered ring, since this provides a better external quantum efficiency for the light-emitting device of this embodiment, and these rings may have a substituent. Ring L 1is preferably a monocyclic or bicyclic to heptacyclic aromatic heterocycle containing one or more nitrogen atoms in the ring, since the external quantum efficiency of the light-emitting device of this embodiment is more excellent; more preferably a monocyclic or bicyclic to pentacyclic aromatic heterocycle containing one or more nitrogen atoms in the ring; even more preferably a monocyclic, bicyclic or tricyclic aromatic heterocycle containing one or more nitrogen atoms in the ring; particularly preferably a monocyclic or bicyclic aromatic heterocycle containing one or more nitrogen atoms in the ring; and particularly preferably a monocyclic aromatic heterocycle containing one or more nitrogen atoms in the ring, and these rings may have a substituent.

[0074] Ring L 1 is preferably a pyridine ring, a diazabenzene ring, an azanaphthalene ring, a diazanaphthalene ring, a triazole ring, or a diazole ring, since the external quantum efficiency of the light-emitting element of this embodiment is further improved, more preferably a pyridine ring, an azanaphthalene ring, a triazole ring, or a diazole ring, and even more preferably a pyridine ring or a triazole ring, and these rings may have a substituent.

[0075] Since the metal complex represented by formula (1) can be easily synthesized, ring L 1 If there are multiple rings, there are multiple rings L 1 At least two of the rings L are preferably the same. 1 It is more preferred that all of the following are the same:

[0076] Ring L 2 The number of carbon atoms in the polycyclic aromatic hydrocarbon ring is usually 7 to 60, preferably 8 to 40, more preferably 9 to 30, and even more preferably 10 to 20, not including the number of carbon atoms in the substituent.

[0077] Ring L 2 Examples of the polycyclic aromatic hydrocarbon ring in the formula (I) include the polycyclic aromatic hydrocarbon rings exemplified in the section on aromatic hydrocarbon groups above, and the aromatic hydrocarbon ring may have a substituent.

[0078] Ring L 2 The polycyclic aromatic hydrocarbon ring in the formula (I) is preferably a polycyclic aromatic hydrocarbon ring containing a 5-membered ring or a 6-membered ring, since the external quantum efficiency of the light-emitting device of this embodiment is superior, more preferably a polycyclic aromatic hydrocarbon ring containing a 6-membered ring, and even more preferably a polycyclic aromatic hydrocarbon ring containing a 5-membered ring and a 6-membered ring, and these rings may have a substituent. Ring L 2 The polycyclic aromatic hydrocarbon ring in the formula (I) is preferably a 2- to 13-ring aromatic hydrocarbon ring, more preferably a 2- to 8-ring aromatic hydrocarbon ring, still more preferably a 2- to 5-ring aromatic hydrocarbon ring, particularly preferably a 3- or 4-ring aromatic hydrocarbon ring, and particularly preferably a 3-ring aromatic hydrocarbon ring, and these rings may have a substituent, since the external quantum efficiency of the light-emitting device of this embodiment is superior.

[0079] Ring L 2 The polycyclic aromatic hydrocarbon ring in the formula (I) is preferably a naphthalene ring, an indene ring, an anthracene ring, a phenanthrene ring, a dihydrophenanthrene ring, a fluorene ring, a benzanthracene ring, a benzophenanthrene ring, a benzofluorene ring, a dibenzanthracene ring, a dibenzophenanthrene ring, a dibenzofluorene ring, an indenofluorene ring, or a benzofluoranthene ring, since this will result in a more excellent external quantum efficiency of the light-emitting device of this embodiment, and more preferably an anthracene ring, a phenanthrene ring, a dihydrophenanthrene ring, a fluorene ring, a benzanthracene ring, a benzophenanthrene ring, or a benzofluorene ring. More preferably, it is a phenanthrene ring, a dihydrophenanthrene ring, a fluorene ring, a benzophenanthrene ring, or a benzofluorene ring, particularly preferably a phenanthrene ring, a dihydrophenanthrene ring, or a fluorene ring, and particularly preferably a fluorene ring, and these rings may have a substituent.

[0080] Ring L 2The number of carbon atoms in the polycyclic aromatic heterocycle in the formula (I) is usually 1 to 60, preferably 5 to 40, more preferably 8 to 30, and even more preferably 10 to 20, not including the number of carbon atoms in the substituent. 2 The number of heteroatoms in the polycyclic aromatic heterocycle in the formula (I) is usually 1 to 30, preferably 1 to 10, more preferably 1 to 5, still more preferably 1 to 3, and particularly preferably 1, not including the number of heteroatoms in the substituents. 2 The heteroatom of the polycyclic aromatic heterocycle in the formula (I) is preferably an oxygen atom, a nitrogen atom or a sulfur atom, more preferably a nitrogen atom or a sulfur atom, and even more preferably a sulfur atom.

[0081] Ring L 2 Examples of the polycyclic aromatic heterocycle in the formula (I) include the polycyclic aromatic heterocycles exemplified above in the section on heterocyclic groups, and the aromatic heterocycle may have a substituent. Ring L 2 The polycyclic aromatic heterocycle in the formula (I) is preferably a polycyclic aromatic heterocycle containing a 5-membered ring or a 6-membered ring, more preferably a polycyclic aromatic heterocycle containing a 6-membered ring, and even more preferably a polycyclic aromatic heterocycle containing a 5-membered ring and a 6-membered ring, and these rings may have a substituent, since the external quantum efficiency of the light-emitting device of this embodiment is more excellent. Ring L 2 The polycyclic aromatic heterocycle in the formula (I) is preferably a bicyclic to ten-cyclic aromatic heterocycle, more preferably a bicyclic to pentacyclic aromatic heterocycle, still more preferably a tricyclic or tetracyclic aromatic heterocycle, and particularly preferably a tricyclic aromatic heterocycle, and these rings may have a substituent, since the external quantum efficiency of the light-emitting device of this embodiment is more excellent.

[0082] Ring L 2As the polycyclic aromatic heterocycle in the above, an azanaphthalene ring, a diazanaphthalene ring, a benzofuran ring, a benzothiophene ring, an indole ring, a benzodiazole ring, a benzotriazole ring, a dibenzofuran ring, a dibenzothiophene ring, a carbazole ring, an azacarbazole ring, a diazacarbazole ring, a phenoxazine ring, a phenothiazine ring, a 9,10-dihydroacridine ring, a 5,10-dihydrophenazine ring, an acridone ring, a phenazaborine ring, or an azaanthracene ring is preferable, since the external quantum efficiency of the light-emitting element of this embodiment is further improved. ring, diazaanthracene ring, azaphenanthrene ring, diazaphenanthrene ring, benzocarbazole ring, azabenzocarbazole ring, diazabenzocarbazole ring, benzonaphthofuran ring, benzonaphthothiophene ring, dibenzocarbazole ring, indolocarbazole ring, indenocarbazole ring, azaindolocarbazole ring, diazaindenocarbazole ring, or diazaindenocarbazole ring, more preferably an azanaphthalene ring, diazanaphthalene ring, benzofuran ring, or benzothiophene ring. ring, indole ring, dibenzofuran ring, dibenzothiophene ring, carbazole ring, azacarbazole ring, diazacarbazole ring, phenoxazine ring, phenothiazine ring, 9,10-dihydroacridine ring, 5,10-dihydrophenazine ring, acridone ring, phenazaborine ring, azaanthracene ring, diazaanthracene ring, azaphenanthrene ring, diazaphenanthrene ring, benzocarbazole ring, azabenzocarbazole ring, diazabenzocarbazole ring, benzonaphthofuran ring or benzonaphthothiophene ring, more preferred Preferably, the ring is a dibenzofuran ring, a dibenzothiophene ring, a carbazole ring, an azacarbazole ring, a diazacarbazole ring, a phenoxazine ring, a phenothiazine ring, a 9,10-dihydroacridine ring, a 5,10-dihydrophenazine ring, an acridone ring, a benzocarbazole ring, an azabenzocarbazole ring, a diazabenzocarbazole ring, a benzonaphthofuran ring, or a benzonaphthothiophene ring, and more preferably, a dibenzofuran ring, a dibenzothiophene ring, a carbazole ring, a phenoxazine ring, a phenothiazine ring, or a 9,10-dihydroacridine ring. A cridine ring, a 5,10-dihydrophenazine ring or an acridone ring is preferred, and a dibenzofuran ring, a dibenzothiophene ring or a carbazole ring is particularly preferred, and these rings may have a substituent.

[0083] Since the external quantum efficiency of the light-emitting device of this embodiment is superior, 2 is preferably a polycyclic aromatic hydrocarbon ring, and the aromatic hydrocarbon ring may have a substituent.

[0084] Ring L 1 When the ring L is an aromatic heterocycle containing a five-membered ring, the external quantum efficiency of the light-emitting device of this embodiment is superior. 2 is preferably a polycyclic aromatic hydrocarbon ring or a polycyclic aromatic heterocycle containing at least one of a sulfur atom and a nitrogen atom in the ring. Ring L 2 In the above formula, examples of the polycyclic aromatic heterocycle containing at least one of a sulfur atom and a nitrogen atom in the ring include polycyclic aromatic heterocycles containing at least one of a sulfur atom and a nitrogen atom among the aromatic heterocycles exemplified in the above section on heterocyclic groups, and the aromatic heterocycle may have a substituent.

[0085] Ring L 2In the above, the polycyclic aromatic heterocycle containing at least one of a sulfur atom and a nitrogen atom in the ring is preferably an azanaphthalene ring, a diazanaphthalene ring, a benzothiophene ring, an indole ring, a benzodiazole ring, a benzotriazole ring, a dibenzothiophene ring, a carbazole ring, an azacarbazole ring, a diazacarbazole ring, a phenothiazine ring, a 9,10-dihydroacridine ring, a 5,10-dihydrophenazine ring, an acridone ring, a phenazaborine ring, an azaan ring, or a benzothiophene ring, because the external quantum efficiency of the light-emitting element of this embodiment is further improved. athracene ring, diazaanthracene ring, azaphenanthrene ring, diazaphenanthrene ring, benzocarbazole ring, azabenzocarbazole ring, diazabenzocarbazole ring, benzonaphthothiophene ring, dibenzocarbazole ring, indolocarbazole ring, indenocarbazole ring, azaindolocarbazole ring, diazaindenocarbazole ring, or diazaindenocarbazole ring, more preferably an azanaphthalene ring, diazanaphthalene ring, benzothiophene ring, indole ring, or dibenzofuran ring. ring, dibenzothiophene ring, carbazole ring, azacarbazole ring, diazacarbazole ring, phenothiazine ring, 9,10-dihydroacridine ring, 5,10-dihydrophenazine ring, acridone ring, phenazaborine ring, azaanthracene ring, diazaanthracene ring, azaphenanthrene ring, diazaphenanthrene ring, benzocarbazole ring, azabenzocarbazole ring, diazabenzocarbazole ring or benzonaphthothiophene ring, more preferably a dibenzothiophene ring, carbazole ring, azacarbazole ring or diazacarbazole ring. The ring is preferably a dibenzothiophene ring, a carbazole ring, a phenothiazine ring, a 9,10-dihydroacridine ring, a 5,10-dihydrophenazine ring, an acridone ring, a benzocarbazole ring, an azabenzocarbazole ring, a diazabenzocarbazole ring, or a benzonaphthothiophene ring, more preferably a dibenzothiophene ring, a carbazole ring, a phenothiazine ring, a 9,10-dihydroacridine ring, a 5,10-dihydrophenazine ring, or an acridone ring, and even more preferably a dibenzothiophene ring or a carbazole ring, and these rings may have a substituent.

[0086] Ring L2 In the polycyclic aromatic heterocycle containing at least one of a sulfur atom and a nitrogen atom in the ring, it is preferable that the polycyclic aromatic heterocycle does not contain an oxygen atom in the ring, since the external quantum efficiency of the light-emitting device of this embodiment is further improved.

[0087] Ring L 1 and ring L 2 The substituent that may be possessed by is preferably an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, an aryloxy group, a monovalent heterocyclic group, a substituted amino group, or a halogen atom, more preferably an alkyl group, a cycloalkyl group, an aryl group, a monovalent heterocyclic group, or a substituted amino group, still more preferably an alkyl group, an aryl group, or a monovalent heterocyclic group, and particularly preferably an aryl group or It is a monovalent heterocyclic group, and these groups may further have a substituent.

[0088] In the metal complex represented by formula (1), the external quantum efficiency of the light-emitting device of this embodiment is superior, so 1 and ring L 2 At least one of these preferably has a substituent.

[0089] Ring L 1 and ring L 2 The alkyl group in the substituent that may be present is preferably a methyl group, an ethyl group, a propyl group, a butyl group, a tert-butyl group, a pentyl group, a 1,1-dimethylpentyl group, a hexyl group, a heptyl group, an octyl group, or a 2-ethylhexyl group, and more preferably a methyl group, a pentyl group, a 1,1-dimethylpentyl group, or an octyl group, and these groups may have a substituent.

[0090] Ring L 1 and ring L 2 The aryl group in the substituent that may be present is preferably a phenyl group, a naphthyl group, a phenanthrenyl group, a dihydrophenanthrenyl group, or a fluorenyl group, more preferably a phenyl group or a fluorenyl group, and even more preferably a phenyl group, and these groups may have a substituent.

[0091] Ring L 1 and ring L 2 In the aryloxy group in the substituent that may be possessed by ring L, examples and preferred ranges of aryl are as follows: 1 and ring L 2 The examples and preferred range of the aryl group in the substituent that may be possessed by the group are the same as those of the aryl group.

[0092] Ring L 1 and ring L 2 The monovalent heterocyclic group in the substituent that may be contained in the group is preferably a pyridyl group, a pyrimidinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a dibenzofuranyl group, a dibenzothienyl group, a carbazolyl group, an azacarbazolyl group, a diazacarbazolyl group, a phenoxazinyl group, or a phenothiazinyl group, more preferably a pyridyl group, a pyrimidinyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothienyl group, or a carbazolyl group, still more preferably a pyridyl group, a pyrimidinyl group, or a triazinyl group, and particularly preferably a triazinyl group, and these groups may have a substituent.

[0093] Ring L 1 and ring L 2 In the substituted amino group in the substituent that may be possessed by ring L, the substituent possessed by the amino group is preferably an aryl group or a monovalent heterocyclic group, more preferably an aryl group, and these groups may further possess a substituent. Examples and preferred ranges of the aryl group in the substituent possessed by the amino group are as follows: 1 and ring L 2 Examples and preferred ranges of the aryl group in the substituent that the amino group may have are the same as those of the ring L. 1 and ring L 2 The examples and preferred range of the monovalent heterocyclic group in the substituent that may be possessed by the group are the same as those of the monovalent heterocyclic group.

[0094] Ring L 1 and ring L 2As the halogen atom in the substituent that may be possessed by the group, a fluorine atom is preferred.

[0095] Ring L 1 and ring L 2 The substituent that may be further substituted by the substituent that may be substituted by is preferably an alkyl group, a cycloalkyl group, an aryl group, a monovalent heterocyclic group, or a substituted amino group, more preferably an alkyl group, a cycloalkyl group, or an aryl group, and even more preferably an alkyl group or an aryl group, and these groups may further have a substituent.

[0096] Ring L 1 and ring L 2 The aryl group, monovalent heterocyclic group or substituted amino group in the substituent that may be contained in the group is preferably a group represented by formula (DA) to formula (DC), more preferably a group represented by formula (DA) or formula (DB), since the external quantum efficiency of the light-emitting device of this embodiment is more excellent.

[0097] [ka]

[0098] [In the formula, m DA1 ~m DA3 each independently represents an integer of 0 or greater. G DA represents a nitrogen atom, an aromatic hydrocarbon group or a heterocyclic group, and these groups may have a substituent. Ar DA1 ~Ar DA3 each independently represents an arylene group or a divalent heterocyclic group, and these groups may have a substituent. DA1 ~Ar DA3 When there are multiple, they may be the same or different. T DA represents an aryl group or a monovalent heterocyclic group, and these groups may have a substituent. DA may be the same or different.]

[0099] [ka]

[0100] [In the formula, m DA1 ~m DA7 each independently represents an integer of 0 or greater. G DA represents a nitrogen atom, an aromatic hydrocarbon group or a heterocyclic group, and these groups may have a substituent. DA may be the same or different. Ar DA1 ~Ar DA7 each independently represents an arylene group or a divalent heterocyclic group, and these groups may have a substituent. DA1 ~Ar DA7 When there are multiple, they may be the same or different. T DA represents an aryl group or a monovalent heterocyclic group, and these groups may have a substituent. DA may be the same or different.]

[0101] [ka]

[0102] [In the formula, m DA1 represents an integer greater than or equal to 0. Ar DA1 represents an arylene group or a divalent heterocyclic group, and these groups may have a substituent. DA1 When there are multiple, they may be the same or different. T DA represents an aryl group or a monovalent heterocyclic group, and these groups may have a substituent.]

[0103] m DA1 ~m DA7are each independently an integer of usually 10 or less, preferably an integer of 5 or less, more preferably an integer of 2 or less, and even more preferably 0 or 1. DA2 ~m DA7 are preferably the same integer.

[0104] G DA is preferably an aromatic hydrocarbon group or a heterocyclic group, and more preferably a group formed by removing three hydrogen atoms directly bonded to carbon atoms or nitrogen atoms constituting a benzene ring, a pyridine ring, a pyrimidine ring, a triazine ring, or a carbazole ring, and these groups may have a substituent. G DA The substituent that may be contained in the group is preferably an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, or a monovalent heterocyclic group, and more preferably an alkyl group or a cycloalkyl group, and these groups may have a substituent. G DA is preferably a group represented by formula (GDA-11) to formula (GDA-15), more preferably a group represented by formula (GDA-11) or formula (GDA-14), and even more preferably a group represented by formula (GDA-14).

[0105] [ka]

[0106] [In the formula, * indicates Ar in formula (DA). DA1 , Ar in formula (DB) DA1 , Ar in formula (DB) DA2 or Ar in formula (DB) DA3 Represents a bond with. ** indicates Ar in formula (DA). DA2 , Ar in formula (DB) DA2 , Ar in formula (DB) DA4 or Ar in formula (DB) DA6 Represents a bond with. *** indicates Ar in formula (DA).DA3 , Ar in formula (DB) DA3 , Ar in formula (DB) DA5 or Ar in formula (DB) DA7 Represents a bond with R DA represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, or a monovalent heterocyclic group, and these groups may further have a substituent. DA If there are multiple, they may be the same or different.]

[0107] R DA is preferably a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group or a cycloalkoxy group, more preferably a hydrogen atom, an alkyl group or a cycloalkyl group, and these groups may have a substituent.

[0108] Ar DA1 ~Ar DA7 is preferably a phenylene group, a fluorenediyl group, or a carbazolediyl group, more preferably a group represented by formula (ArDA-1) to formula (ArDA-5), and even more preferably a group represented by formula (ArDA-1) to formula (ArDA-3). Particularly preferred is a group represented by formula (ArDA-2), and these groups may have a substituent.

[0109] [ka]

[0110] [In the formula, R DA represents the same meaning as above. R DB represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may have a substituent. DB If there are multiple, they may be the same or different.]

[0111] R DBis preferably an alkyl group, a cycloalkyl group, an aryl group or a monovalent heterocyclic group, more preferably an aryl group, and these groups may have a substituent.

[0112] Ar DA1 ~Ar DA7 Examples of the substituents that may be possessed by G and the preferred range thereof are as follows: DA The examples and preferred ranges of the substituents that may be possessed by the group are the same as those of the substituents that may be possessed by the group.

[0113] T DA is preferably a group represented by formula (TDA-1) to formula (TDA-3), more preferably a group represented by formula (TDA-1).

[0114] [ka]

[0115] [In the formula, R DA and R DB has the same meaning as above.]

[0116] The group represented by formula (DA) is preferably a group represented by formula (D-A1) to formula (D-A5), more preferably a group represented by formula (D-A1), formula (D-A3) or formula (D-A5), and even more preferably a group represented by formula (D-A3).

[0117] [ka]

[0118] [In the formula, R p1 ~R p4 R each independently represents an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, or a halogen atom. p1 , R p2 and R p4 When there are a plurality of, they may be the same or different. np1 represents an integer of 0 to 5, np2 represents an integer of 0 to 3, np3 represents 0 or 1, and np4 represents an integer of 0 to 4. Multiple np1 may be the same or different.

[0119] The group represented by formula (DB) is preferably a group represented by formula (D-B1) to formula (D-B3), and more preferably a group represented by formula (D-B1).

[0120] [ka]

[0121] [In the formula, R p1 ~R p3 R each independently represents an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, or a halogen atom. p1 and R p2 When there are multiple, they may be the same or different. np1 represents an integer of 0 to 5, np2 represents an integer of 0 to 3, and np3 represents 0 or 1. When there are a plurality of np1 and np2, they may be the same or different.

[0122] The group represented by formula (DC) is preferably a group represented by formula (D-C1) to formula (D-C4), more preferably a group represented by formula (D-C1).

[0123] [ka]

[0124] [In the formula, R p4 ~R p6 R each independently represents an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, or a halogen atom. p4 ~R p6 When there are a plurality of, they may be the same or different. np4 represents an integer of 0 to 4, np5 represents an integer of 0 to 5, and np6 represents an integer of 0 to 5.

[0125] np1 is preferably an integer of 0 to 2, more preferably 0 or 1. np2 is preferably 0 or 1, more preferably 0. np3 is preferably 0. np4 is preferably an integer of 0 to 2, more preferably 0. np5 is preferably an integer of 0 to 3, more preferably 0 or 1. np6 is preferably an integer of 0 to 2, more preferably 0 or 1.

[0126] R p1 ~R p6 The alkyl group or cycloalkyl group in the formula (I) is preferably a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, a hexyl group, a 2-ethylhexyl group, a cyclohexyl group, or a tert-octyl group.

[0127] R p1 ~R p6 The alkoxy group or cycloalkoxy group in the formula (I) is preferably a methoxy group, a 2-ethylhexyloxy group, or a cyclohexyloxy group.

[0128] R p1 ~R p6 is preferably an alkyl group which may have a substituent or a cycloalkyl group which may have a substituent, more preferably an alkyl group which may have a substituent, and even more preferably a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, a hexyl group, a 2-ethylhexyl group or a tert-octyl group.

[0129] Ring L 1 When there are a plurality of substituents that may be possessed by ring L, it is preferred that they are not bonded to each other to form a ring together with the atoms to which they are bonded. 2 When there are a plurality of substituents that may be possessed by ring L, it is preferred that they are not bonded to each other to form a ring together with the atoms to which they are bonded. 1and the substituents which may be present on ring L 2 It is preferred that the substituents which may be possessed by the group do not bond to each other to form a ring together with the atoms to which they are bonded.

[0130] [Anionic bidentate ligand] A 1 -G 1 -A 2 Examples of the anionic bidentate ligand represented by the formula include the ligand represented by the formula below: 1 -G 1 -A 2 The anionic bidentate ligand represented by the subscript n 1 The number is different from the ligand defined by

[0131] [ka]

[0132] [ka]

[0133] [ka]

[0134] During the ceremony, * indicates the site that binds to M. R L1 represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, a monovalent heterocyclic group, or a halogen atom, and these groups may have a substituent. L1 may be the same or different. R L2 is an alkyl group, a cycloalkyl group, an aryl group, a monovalent heterocyclic group, or a halogen atom. These groups may have a substituent.

[0135] R L1is preferably a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group or a fluorine atom, more preferably a hydrogen atom or an alkyl group, and these groups may have a substituent.

[0136] R L2 is preferably an alkyl group or an aryl group, and these groups may have a substituent.

[0137] R L1 The substituent that may be substituted by the alkyl group, cycloalkyl group or aryl group is preferred, and an alkyl group or aryl group is more preferred, and these groups may further have a substituent.

[0138] R L1 The substituent that may be further substituted by the substituent that may be substituted by is preferably an alkyl group, a cycloalkyl group, or an aryl group, more preferably an alkyl group or an aryl group, and these groups may further have a substituent.

[0139] R L2 The substituent that may be substituted by the alkyl group, cycloalkyl group or aryl group is preferred, and an alkyl group or aryl group is more preferred, and these groups may further have a substituent.

[0140] R L2 The substituent that may be further substituted by the substituent that may be substituted by is preferably an alkyl group, a cycloalkyl group, or an aryl group, more preferably an alkyl group or an aryl group, and these groups may further have a substituent.

[0141] The metal complex represented by formula (1) is preferably a metal complex represented by formula (1-A), since the external quantum efficiency of the light-emitting device of this embodiment is more excellent.

[0142] Ring R B1 and ring R B2In the formula, the number of carbon atoms in the aromatic hydrocarbon ring is usually 6 to 60, preferably 6 to 30, and more preferably 6 to 18, not including the number of carbon atoms in the substituent.

[0143] Ring R B1 and ring R B2 Examples of the aromatic hydrocarbon ring in include a benzene ring, a naphthalene ring, an anthracene ring, an indene ring, a fluorene ring, a spirobifluorene ring, a phenanthrene ring, a dihydrophenanthrene ring, a pyrene ring, a chrysene ring, and a triphenylene ring. Of these, a benzene ring, a naphthalene ring, an anthracene ring, a fluorene ring, a spirobifluorene ring, a phenanthrene ring, or a dihydrophenanthrene ring is preferred, a benzene ring, a naphthalene ring, a fluorene ring, or a spirobifluorene ring is more preferred, and a benzene ring is even more preferred. These rings may have a substituent.

[0144] Ring R B1 and ring R B2 In the formula, the number of carbon atoms in the aromatic heterocycle is usually 2 to 60, preferably 3 to 30, and more preferably 4 to 15, not including the number of carbon atoms in the substituent.

[0145] Ring R B1 and ring R B2 Examples of the aromatic heterocycle in the formula (I) include a pyrrole ring, a diazole ring, a triazole ring, a furan ring, a thiophene ring, an oxadiazole ring, a thiadiazole ring, a pyridine ring, a diazabenzene ring, a triazine ring, an azanaphthalene ring, a diazanaphthalene ring, a triazanaphthalene ring, an azaanthracene ring, a diazaanthracene ring, a triazaanthracene ring, an azaphenanthrene ring, a diazaphenanthrene ring, a triazaphenanthrene ring, a dibenzofuran ring, a dibenzothiophene ring, a dibenzosilole ring, and a dibenzophospho Examples of the ring include a pyridine ring, a carbazole ring, an azacarbazole ring, a diazacarbazole ring, a phenoxazine ring, a phenothiazine ring, a dihydroacridine ring, and a dihydrophenazine ring. Preferred are a pyridine ring, a diazabenzene ring, an azanaphthalene ring, a diazanaphthalene ring, an azaanthracene ring, a diazaphenanthrene ring, a dibenzofuran ring, a dibenzothiophene ring, a carbazole ring, a phenoxazine ring, a phenothiazine ring, a dihydroacridine ring, and a dihydrophenazine ring. More preferred are a pyridine ring, a diazabenzene ring, an azanaphthalene ring, a diazanaphthalene ring, a dibenzofuran ring, a dibenzothiophene ring, and a carbazole ring. These rings may have a substituent.

[0146] Ring R B1 and ring R B2 is the ring R B1 and ring R B2 Preferably, at least one of the rings R is an aromatic hydrocarbon ring. B1 and ring R B2 and more preferably, both are aromatic hydrocarbon rings.

[0147] Ring R B1 and ring R B2 Examples of the substituents that may be possessed by ring L and the preferred range thereof are as follows: 2 The examples and preferred ranges of the substituents that may be possessed by the group are the same as those of the substituents that may be possessed by the group.

[0148] Ring R B1 and ring R B2 Examples and preferred ranges of the substituents that may be further substituted by the substituents that may be substituted by ring L 2 The examples and preferred ranges of the substituents which may be further possessed by the group are the same as those of the substituents which may be further possessed by the group.

[0149] X a and X b At least one of the groups is preferably a divalent group, and it is more preferable that one is a direct bond and the other is a divalent group. X a and X bIn the formula, the divalent group is preferably -CR Xa 2-, -CR Xa 2-CR Xa 2-, -CR Xa =CR Xa a group represented by -, a group represented by -C(=O)-, a group represented by -O-, a group represented by -S-, or -NR Xa’ -, and more preferably -CR Xa 2-, -CR Xa 2-CR Xa 2-, -CR Xa =CR Xa -, -C(=O)- or -S-, and more preferably -CR Xa 2-, -CR Xa 2-CR Xa 2-, -CR Xa =CR Xa - or -S-, and particularly preferably -CR Xa It is a group represented by -2- or a group represented by -S-.

[0150] X a and X b The combination of X a Ga-CR Xa 2-, -CR Xa 2-CR Xa 2-, -CR Xa =CR Xa - or -C(=O)-, and X b is a direct bond, X a Ga-CR Xa 2-, -CR Xa 2-CR Xa 2-, -CR Xa =CR Xa - or -C(=O)-, and X b Ga-NR Xa’ - a combination represented by X a is an oxygen atom and X b is a direct bond, X ais an oxygen atom and X b Ga-NR Xa’ - a combination represented by X a is a sulfur atom and X b is a direct bond, X a Ga-NR Xa’ - is a group represented by X b is a direct bond, X a is a direct bond and X b Ga-CR Xa 2-, -CR Xa 2-CR Xa 2-, -CR Xa =CR Xa - or a group represented by -C(=O)-, or X a is a direct bond and X b is a sulfur atom, and X a Ga-CR Xa 2-, -CR Xa 2-CR Xa 2-, -CR Xa =CR Xa - or -C(=O)-, and X b is a direct bond, X a is a direct bond and X b Ga-CR Xa 2-, -CR Xa 2-CR Xa 2-, -CR Xa =CR Xa - or a group represented by -C(=O)-, or X a is a direct bond and X b is a sulfur atom, and X a Ga-CR Xa 2- -CR Xa 2-CR Xa 2- or -CR Xa =CR Xa - is a group represented by a group represented by X b is a direct bond, or X a is a direct bond and Xb is a sulfur atom, and X a Ga-CR Xa 2- and X b is a direct bond, or X a is a direct bond and X b is a sulfur atom is particularly preferred.

[0151] R Xa and R Xa’ are each independently preferably an alkyl group, a cycloalkyl group, an aryl group or a monovalent heterocyclic group, and more preferably an alkyl group or an aryl group.

[0152] The metal complex represented by formula (1-A) is a ring L 1 is an aromatic heterocycle containing a five-membered ring, the external quantum efficiency of the light-emitting device of this embodiment is more excellent, so it is preferable that at least one of (i), (ii), and (iii) is satisfied, and it is more preferable that (i) or (iii) is satisfied. (i)X a and X b At least one of -S- and / or -N(R Xa’ )-, and the group may have a substituent. (ii) Ring R B1 and ring R B2 At least one of the above is an aromatic heterocycle containing at least one of a sulfur atom and a nitrogen atom in the ring, and the aromatic heterocycle may have a substituent. (iii) Ring R B1 and ring R B2 is an aromatic hydrocarbon ring, and X a and X b are each independently a direct bond or a divalent group, and the divalent group is -C(=O)- and -C(R Xa )2-, and the group is a divalent group consisting of at least one selected from the group consisting of:

[0153] Ring R B1 and ring R B2In the formula (I), the aromatic heterocycle containing at least one kind of atom selected from a sulfur atom and a nitrogen atom in the ring is preferably a pyridine ring, a diazabenzene ring, an azanaphthalene ring, a diazanaphthalene ring, an azaanthracene ring, a diazaphenanthrene ring, a dibenzothiophene ring, a carbazole ring, a phenothiazine ring, a dihydroacridine ring, or a dihydrophenazine ring, more preferably a pyridine ring, a diazabenzene ring, an azanaphthalene ring, a diazanaphthalene ring, a dibenzothiophene ring, or a carbazole ring, and even more preferably a pyridine ring or a diazabenzene ring, and these rings may have a substituent.

[0154] The metal complex represented by formula (1-A) is preferably a metal complex represented by formula (1-A1), a metal complex represented by formula (1-A2), or a metal complex represented by formula (1-A3), since the external quantum efficiency of the light-emitting element of this embodiment is superior.

[0155] R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 and R 12 Examples and preferred ranges of the aryl group, aryloxy group, monovalent heterocyclic group, substituted amino group and halogen atom in the ring R B1 and ring R B2 The examples and preferred ranges of the aryl group, aryloxy group, monovalent heterocyclic group, substituted amino group and halogen atom in the substituent that may be possessed by the group are the same as those of the aryl group, aryloxy group, monovalent heterocyclic group, substituted amino group and halogen atom in the substituent that may be possessed by the group.

[0156] R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 and R 12 Examples of the substituents that each group may further have and the preferred ranges thereof are as follows: B1 and ring R B2The examples and preferred ranges of the substituents which may be further possessed by the group are the same as those of the substituents which may be further possessed by the group.

[0157] R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 and R 12 When is a group other than the group represented by formula (DA), formula (DB) or formula (DC), it is preferably a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group or a monovalent heterocyclic group, and More preferably, it is a cycloalkyl group, a cycloalkyl group, or an aryl group, still more preferably a hydrogen atom, an alkyl group, or an aryl group, and particularly preferably a hydrogen atom.

[0158] R 6 , R 7 , R 8 and R 9 At least one of R is preferably an aryl group or a monovalent heterocyclic group (more preferably an aryl group), 7 and R 8 It is more preferable that at least one of the groups is an aryl group or a monovalent heterocyclic group (more preferably an aryl group).

[0159] In formula (1-A1), R 6 and X a , R 9 and X b , and R 10 and X b are bonded to each other directly or via a divalent group to form a ring together with the atoms to which they are bonded, and X a and / or X b However, each independently, -CR Xa 2- or -NR Xa’ -, R 6 , R 9 and R 10 At least one of R Xaand / or R Xa’ and preferably bonded directly to each other or via a divalent group to form a ring together with the atom to which each is bonded. In formula (1-A2), R 5 and X a , R 6 and X a , R 9 and X b , and R 10 and X b are bonded to each other directly or via a divalent group to form a ring together with the atoms to which they are bonded, and X a and / or X b However, each independently, -CR Xa 2- or -NR Xa’ -, R 5 , R 6 , R 9 and R 10 At least one of R Xa and / or R Xa’ and preferably bonded directly to each other or via a divalent group to form a ring together with the atom to which each is bonded. In formula (1-A3), R 6 and X a , R 9 and X b , and R 12 and X a are bonded to each other directly or via a divalent group to form a ring together with the atoms to which they are bonded, and X a and / or X b However, each independently, -CR Xa 2- or -NR Xa’ -, R 6 , R 9 and R 12 At least one of R Xa and / or R Xa’ and preferably bonded directly to each other or via a divalent group to form a ring together with the atom to which each is bonded.

[0160] The metal complexes represented by formula (1-A1), (1-A2), and (1-A3) are each a ring L 1 When X is an aromatic heterocycle containing a five-membered ring, the external quantum efficiency of the light-emitting device of this embodiment is superior. a and X b are each independently a direct bond or a divalent group, and the divalent group is -S-, -C(=O)-, -C(R Xa )2- and -N(R Xa’ )-, and the group may have a substituent.

[0161] The metal complex represented by formula (1-A) is preferably a metal complex represented by formula (1-A1-1), a metal complex represented by formula (1-A2-1), or a metal complex represented by formula (1-A3-1), since the external quantum efficiency of the light-emitting element of this embodiment is superior, and more preferably a metal complex represented by formula (1-A2-1).

[0162] [ka]

[0163] [In the formula, M, n 1 , n 2 , X a , X b , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 and A 1 -G 1 -A 2 represents the same meaning as above. R 1 , R 2 , R 3 and R 4R each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, an aryloxy group, a monovalent heterocyclic group, a substituted amino group, or a halogen atom, and these groups may have a substituent. 1 , R 2 , R 3 and R 4 When there are multiple R, they may be the same or different. 4 and R 5 may be bonded to each other to form a ring together with the atoms to which they are bonded. In formula (1-A1-1), R 4 and X a , R 6 and X a , R 9 and X b , and R 10 and X b may be bonded to each other directly or via a divalent group to form a ring together with the atom to which they are bonded. In formula (1-A2-1), R 5 and X a , R 6 and X a , R 9 and X b , and R 10 and X b may be bonded to each other directly or via a divalent group to form a ring together with the atom to which they are bonded. In formula (1-A3-1), R 6 and X a , R 9 and X b , and R 12 and X a may be bonded to each other directly or via a divalent group to form a ring together with the atom to which they are bonded.

[0164] R 1 , R 2 , R 3 and R 4 Examples and preferred ranges of the aryl group, aryloxy group, monovalent heterocyclic group, substituted amino group and halogen atom in1 The examples and preferred ranges of the aryl group, aryloxy group, monovalent heterocyclic group, substituted amino group and halogen atom in the substituent that may be possessed by the group are the same as those of the aryl group, aryloxy group, monovalent heterocyclic group, substituted amino group and halogen atom in the substituent that may be possessed by the group.

[0165] R 1 , R 2 , R 3 and R 4 Examples of the substituents that each group may further have and the preferred ranges thereof are as follows: 1 The examples and preferred ranges of the substituents which may be further possessed by the group are the same as those of the substituents which may be further possessed by the group.

[0166] R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 and R 10 At least one of the groups represented by formula (DA), formula (DB) or formula (DC) is preferably a group represented by formula (DA), formula (DB) or formula (DC), and R 1 , R 2 , R 3 and R 4 It is more preferable that at least one of R is a group represented by formula (DA), formula (DB) or formula (DC), 2 is more preferably a group represented by formula (DA), formula (DB) or formula (DC), and R 2 is particularly preferably a group represented by formula (DA) or formula (DB).

[0167] In formula (1-A1-1), R 4 and X a , R 6 and X a , R 9 and X b , and R 10 and X b are bonded to each other directly or via a divalent group to form a ring together with the atoms to which they are bonded, and X a and / or X bHowever, each independently, -CR Xa 2- or -NR Xa’ -, R 4 , R 6 , R 9 and R 10 At least one of each is R Xa and / or R Xa’ and preferably bonded directly to each other or via a divalent group to form a ring together with the atom to which each is bonded. In formula (1-A2-1), R 5 and X a , R 6 and X a , R 9 and X b , and R 10 and X b are bonded to each other directly or via a divalent group to form a ring together with the atoms to which they are bonded, and X a and / or X b However, each independently, -CR Xa 2- or -NR Xa’ -, R 5 , R 6 , R 9 and R 10 At least one of each is R Xa and / or R Xa’ and preferably bonded directly to each other or via a divalent group to form a ring together with the atom to which each is bonded. In formula (1-A3-1), R 6 and X a , R 9 and X b , and R 12 and X a are bonded to each other directly or via a divalent group to form a ring together with the atoms to which they are bonded, and X a and / or X b However, each independently, -CR Xa 2- or -NR Xa’ -, R 6, R 9 and R 12 At least one of each is R Xa and / or R Xa’ and preferably bonded directly to each other or via a divalent group to form a ring together with the atom to which each is bonded.

[0168] Examples of the metal complex represented by formula (1) include metal complexes represented by the following formula:

[0169] [ka]

[0170] [ka]

[0171] [ka]

[0172] [ka]

[0173] [ka]

[0174] [ka]

[0175] [ka]

[0176] [ka]

[0177] [ka]

[0178] [In the formula, Z A represents a group represented by -CH= or a group represented by -N=. Z A When there are multiple groups, they may be the same or different. Z B represents a group represented by -O- or a group represented by -S-. B When there are multiple, they may be the same or different.

[0179] The metal complex represented by formula (1) is described, for example, in "Journal of the American Chemical Society, Vol. 107, 1431-1432 (1985)" and "Journal of the American Chemical Society, Vol. The compound can be synthesized according to the methods described in "Journal of the Japanese Society, Vol. 106, 6647-6653 (1984)", JP-T-2004-530254, JP-A-2008-179617, JP-A-2011-105701, JP-T-2007-504272, WO 2006 / 121811, JP-A-2013-147450, and JP-A-2014-224101.

[0180] [Low molecular weight compounds consisting only of main group elements] The low-molecular-weight compound consisting only of a main group element is preferably a compound having at least one function selected from the group consisting of light-emitting property, hole-injecting property, hole-transporting property, electron-injecting property, and electron-transporting property, and more preferably a host material having at least one function selected from the group consisting of hole-injecting property, hole-transporting property, electron-injecting property, and electron-transporting property.

[0181] The host material means a material that transfers electric energy to the light-emitting material. Since the host material can transfer electric energy to the light-emitting material efficiently and the light-emitting material can emit light more efficiently, the lowest excited triplet state of the host material has an energy level higher than that of the light-emitting material. The excited singlet state is preferably at an energy level higher than the lowest excited singlet state of the light-emitting material.

[0182] The low molecular weight compound consisting of only a main group element is preferably a compound represented by formula (H-1).

[0183] Ar H1 and Ar H2 is preferably a phenyl group, a fluorenyl group, a spirobifluorenyl group, a pyridyl group, a pyrimidinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a thienyl group, a benzothienyl group, a dibenzothienyl group, a furyl group, a benzofuryl group, a dibenzofuryl group, a pyrrolyl group, an indolyl group, an azaindolyl group, a carbazolyl group, an azacarbazolyl group, a diazacarbazolyl group, a phenoxazinyl group or a phenothiazinyl group, and A fluorenyl group, a pyridyl group, a pyrimidinyl group, a triazinyl group, a dibenzothienyl group, a dibenzofuryl group, a carbazolyl group, or an azacarbazolyl group is more preferred, a phenyl group, a pyridyl group, a carbazolyl group, or an azacarbazolyl group is even more preferred, a group represented by formula (TDA-1) or (TDA-3) is particularly preferred, and a group represented by formula (TDA-3) is especially preferred, and these groups may have a substituent.

[0184] Ar H1 and Ar H2The substituent that may be substituted by the group is preferably a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, or a monovalent heterocyclic group, more preferably an alkyl group, a cycloalkoxy group, an alkoxy group, or a cycloalkoxy group, still more preferably an alkyl group or a cycloalkoxy group, and particularly preferably an alkyl group, and these groups may further have a substituent.

[0185] n H1 is preferably 1. H2 is preferably 0.

[0186] n H3 is usually an integer of 0 or more and 10 or less, preferably an integer of 0 or more and 5 or less, more preferably an integer of 1 or more and 3 or less, and particularly preferably 1.

[0187] L H1 is preferably an arylene group or a divalent heterocyclic group.

[0188] L H1 is preferably a group represented by formula (A-1) to formula (A-3), formula (A-8) to formula (A-10), formula (AA-1) to formula (AA-6), formula (AA-10) to formula (AA-21), or formula (AA-24) to formula (AA-34), more preferably a group represented by formula (A-1), formula (A-2), formula (A-8), formula (A-9), formula (AA-1) to formula (AA-4), formula (AA-10) to formula (AA-15), or formula (AA-29) to formula (AA-34), and more preferably a group represented by formula (A-1), formula (A-2), formula (A-8), formula (A-9), formula ( It is more preferred that the group is a group represented by formula (AA-2), formula (AA-4), formula (AA-10) to formula (AA-15), it is particularly preferred that the group is a group represented by formula (A-1), formula (A-2), formula (A-8), formula (AA-2), formula (AA-4), formula (AA-10), formula (AA-12) or formula (AA-14), it is particularly preferred that the group is a group represented by formula (A-1), formula (A-2), formula (AA-2), formula (AA-4) or formula (AA-14), it is most preferred that the group is a group represented by formula (AA-4) or formula (AA-14).

[0189] n H11 is preferably an integer of 1 or more and 5 or less, more preferably an integer of 1 or more and 3 or less, and even more preferably 1.

[0190] R H11 is preferably a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group or a monovalent heterocyclic group, more preferably a hydrogen atom, an alkyl group or a cycloalkyl group, and even more preferably a hydrogen atom or an alkyl group, and these groups may have a substituent. It may be possible.

[0191] L H1 The substituent that may be substituted by the group is preferably a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, or a monovalent heterocyclic group, more preferably an alkyl group, an alkoxy group, an aryl group, or a monovalent heterocyclic group, still more preferably an alkyl group, an aryl group, or a monovalent heterocyclic group, and particularly preferably an aryl group, and these groups may further have a substituent.

[0192] L H21 is preferably a single bond or an arylene group, more preferably a single bond, and this arylene group may have a substituent.

[0193] L H21 Examples and preferred ranges of the arylene group or divalent heterocyclic group represented by L H1 The examples and preferred ranges of the arylene group or divalent heterocyclic group are the same as those of the arylene group or divalent heterocyclic group represented by the following formula:

[0194] R H21 is preferably an aryl group or a monovalent heterocyclic group, and these groups may have a substituent.

[0195] R H21 Examples and preferred ranges of the aryl group and monovalent heterocyclic group represented by Ar H1 and Ar H2The examples and preferred ranges of the aryl group and monovalent heterocyclic group are the same as those of the aryl group and monovalent heterocyclic group represented by the following formula:

[0196] R H21 Examples of the substituents that may be possessed by Ar and the preferred ranges thereof are as follows: H1 and Ar H2 The examples and preferred ranges of the substituents that may be possessed by are the same as those of the substituents that may be possessed by the group.

[0197] The compound represented by formula (H-1) is preferably a compound represented by formula (H-2).

[0198] [ka]

[0199] In the formula, Ar H1 , Ar H2 , n H3 and L H1 represents the same meaning as above.

[0200] Specific examples of low molecular weight compounds consisting only of main group elements include compounds represented by the following formulas, as well as compounds H1 and H2 described below.

[0201] [ka]

[0202] [ka]

[0203] [ka]

[0204] The compound represented by formula (H-1) can be synthesized according to the method described in JP-A-2010-189630.

[0205] [First composition] The first layer may be a layer containing a composition (hereinafter also referred to as the "first composition") including a metal complex represented by formula (1), a low-molecular-weight compound consisting only of a typical element, and at least one selected from the group consisting of a hole-transporting material, a hole-injecting material, an electron-transporting material, an electron-injecting material, a light-emitting material, and an antioxidant. However, in the first composition, the hole-transporting material, the hole-injecting material, the electron-transporting material, the electron-injecting material, and the light-emitting material are different from the low-molecular-weight compound consisting only of a typical element. In the first composition, the light-emitting material is different from the metal complex represented by formula (1).

[0206] [Hole transport material] The hole transport material is classified into a low molecular weight compound and a high molecular weight compound, and is preferably a high molecular weight compound. The hole transport material may have a crosslinking group.

[0207] Examples of the polymer compound include polyvinylcarbazole and its derivatives, and polyarylene and its derivatives having an aromatic amine structure in the side chain or main chain. The polymer compound may be a compound to which an electron-accepting moiety is bonded. Examples of the electron-accepting moiety include fullerene, tetrafluorotetracyanoquinodimethane, tetracyanoethylene, and trinitrofluorenone, with fullerene being preferred.

[0208] In the first composition, the blending amount of the hole transport material is usually 1 to 400 parts by mass, and preferably 5 to 150 parts by mass, relative to 100 parts by mass of the total of the metal complex represented by formula (1) and the low molecular weight compound consisting only of a typical element. The hole transport material may be used alone or in combination of two or more kinds.

[0209] [Electron transport material] Electron transport materials are classified into low molecular weight compounds and high molecular weight compounds. The electron transport material may have a crosslinking group.

[0210] Examples of low molecular weight compounds include metal complexes having 8-hydroxyquinoline as a ligand, oxadiazole, anthraquinodimethane, benzoquinone, naphthoquinone, anthraquinone, tetracyanoanthraquinodimethane, fluorenone, diphenyldicyanoethylene, and diphenoquinone, as well as derivatives thereof.

[0211] Examples of the polymer compound include polyphenylene, polyfluorene, and derivatives thereof. The polymer compound may be doped with a metal.

[0212] In the first composition, the amount of the electron transport material is usually 1 to 400 parts by mass, and preferably 5 to 150 parts by mass, relative to 100 parts by mass of the total of the metal complex represented by formula (1) and the low-molecular-weight compound consisting only of a typical element. The electron transporting materials may be used alone or in combination of two or more.

[0213] [Hole injection material and electron injection material] The hole injection material and the electron injection material are each classified into a low molecular weight compound and a high molecular weight compound. The hole injection material and the electron injection material may have a crosslinking group.

[0214] 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.

[0215] Examples of the polymer compound include polyaniline, polythiophene, polypyrrole, polyphenylene vinylene, polythienylene vinylene, polyquinoline, polyquinoxaline, and derivatives thereof; and conductive polymers such as polymers containing an aromatic amine structure in the main chain or side chain.

[0216] In the first composition, the blending amount of the hole injection material and the electron injection material is usually 1 to 400 parts by mass, and preferably 5 to 150 parts by mass, relative to 100 parts by mass of the total of the metal complex represented by formula (1) and the low-molecular-weight compound consisting only of a typical element. The electron injection material and the hole injection material may each be used alone or in combination of two or more kinds.

[0217] [Ion doping] When the hole injection material or the electron injection material includes a conductive polymer, the electrical conductivity of the conductive polymer is preferably 1×10 -5 S / cm~1×10 3 In order to set the electrical conductivity of the conductive polymer in this range, the conductive polymer can be doped with an appropriate amount of ions.

[0218] The type of ion to be doped is an anion for a hole injection material, or a cation for an electron injection material. 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 singly or in combination of two or more kinds.

[0219] [Luminescent materials] Light-emitting materials are classified into low molecular weight compounds and high molecular weight compounds. The light-emitting material may have a crosslinking group.

[0220] Examples of low molecular weight compounds include naphthalene and its derivatives, anthracene and its derivatives, perylene and its derivatives, and triplet luminescent complexes having iridium, platinum, or europium as a central metal. Examples of triplet light-emitting complexes include the metal complexes shown below.

[0221] [ka]

[0222] Examples of the polymer compound include polymer compounds containing a phenylene group, a naphthalenediyl group, an anthracenediyl group, a fluorenediyl group, a phenanthrenediyl group, a dihydrophenanthrenediyl group, a group represented by the formula (X) described below, a carbazolediyl group, a phenoxazinediyl group, a phenothiazinediyl group, a pyrenediyl group, and the like.

[0223] In the first composition, the amount of the luminescent material is usually 0.1 to 400 parts by mass, and preferably 5 to 150 parts by mass, relative to 100 parts by mass of the total of the metal complex represented by formula (1) and the low molecular weight compound consisting only of a typical element. The light-emitting materials may be used alone or in combination of two or more.

[0224] [Antioxidants] The antioxidant may be any compound that is soluble in the same solvent as the metal complex represented by formula (1) and the low-molecular-weight compound consisting only of a typical element, and does not inhibit light emission or charge transport. Examples of the antioxidant include phenol-based antioxidants and phosphorus-based antioxidants.

[0225] In the first composition, the blending amount of the antioxidant is usually 0.001 to 10 parts by mass, assuming that the total of the metal complex represented by formula (1) and the low molecular weight compound consisting only of a main group element is 100 parts by mass. The antioxidants may be used alone or in combination of two or more.

[0226] [First Ink] The composition containing the metal complex represented by formula (1), a low molecular weight compound consisting only of a typical element, and a solvent (hereinafter also referred to as "first ink") can be printed by a method 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, nozzle coating, or the like. It can be suitably used in coating methods such as the coating method.

[0227] The viscosity of the first ink may be adjusted depending on the type of application method. However, when the first ink is applied to a printing method in which the solution passes through a discharge device, such as inkjet printing, the viscosity is preferably 1 to 20 mPa s at 25°C, since this reduces clogging and deflection during discharge.

[0228] The solvent contained in the first ink is preferably a solvent that can dissolve or uniformly disperse the solid content in the ink. Examples of the solvent 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-based solvents such as toluene, xylene, mesitylene, ethylbenzene, n-hexylbenzene, and cyclohexylbenzene; cyclohexane, methylcyclohexane, n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane, n-dodecane, and bicyclohexyl. ketone solvents such as acetone, methyl ethyl ketone, cyclohexanone, and acetophenone; ester solvents such as ethyl acetate, butyl acetate, ethyl cellosolve 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 kinds.

[0229] In the first ink, the amount of the solvent is typically 1,000 to 100,000 parts by mass, and preferably 2,000 to 20,000 parts by mass, relative to 100 parts by mass of the total of the metal complex represented by formula (1) and the low molecular weight compound consisting only of a typical element.

[0230] <Second layer> In the light-emitting device of this embodiment, the second layer is a layer containing a crosslinked product of a polymer compound including a structural unit having a crosslinking group (hereinafter also referred to as "polymer compound of the second layer"). The second layer may contain only one type of crosslinked polymer compound of the second layer, or may contain two or more types. In the light-emitting element of this embodiment, the number of types of crosslinked polymer compounds contained in the second layer is usually 1 to 10, and since this facilitates the production of the light-emitting element of this embodiment, it is preferably 1 to 5 types, more preferably 1 to 3 types, even more preferably 1 or 2 types, and particularly preferably 1 type.

[0231] The content of the crosslinked polymer compound in the second layer may be within a range that allows the second layer to function properly. The content of the crosslinked polymer compound in the second layer may be 1 to 100% by mass based on the total amount of the second layer, and is preferably 10 to 100% by mass, more preferably 30 to 100% by mass, even more preferably 50 to 100% by mass, particularly preferably 70 to 100% by mass, and especially preferably 90 to 100% by mass, because this provides a more excellent external quantum efficiency for the light-emitting device of this embodiment.

[0232] [Crosslinked polymer compound of the second layer] The crosslinked polymer compound of the second layer can be obtained by crosslinking the polymer compound of the second layer by the method and conditions described below.

[0233] The structural unit having a crosslinking group contained in the polymer compound of the second layer is preferably a polymer compound containing a structural unit having at least one type of crosslinking group selected from Group A of crosslinking groups, since this provides the light-emitting device of this embodiment with excellent external quantum efficiency.

[0234] The crosslinking group selected from the crosslinking group Group A is preferably a crosslinking group represented by formula (XL-1), formula (XL-9), formula (XL-10) or formula (XL-16) to formula (XL-19), since the external quantum efficiency of the light-emitting device of this embodiment is more excellent, more preferably a crosslinking group represented by formula (XL-1) or formula (XL-16) to formula (XL-19), even more preferably a crosslinking group represented by formula (XL-1) or formula (XL-17) to formula (XL-19), and particularly preferably a crosslinking group represented by formula (XL-1) or formula (XL-17). In the bridging group selected from the bridging group group A, examples and preferred ranges of the substituents that the bridging group may have are described in the Ar Y1 The examples and preferred ranges of the substituents that the group represented by the following formula may have are the same as those. The polymer compound of the second layer may contain only one type of crosslinking group selected from Group A of crosslinking groups, or may contain two or more types, preferably two or more types.

[0235] (Structural Unit Having at Least One Crosslinking Group Selected from Crosslinking Group A) The polymer compound of the second layer preferably contains at least one crosslinking group selected from Crosslinking Group A as a structural unit having at least one crosslinking group selected from Crosslinking Group A, because this provides better crosslinkability for the polymer compound of the second layer and better external quantum efficiency for the light-emitting device of this embodiment. That is, the polymer compound of the second layer is preferably a polymer compound containing a structural unit having at least one crosslinking group selected from Crosslinking Group A.

[0236] When the polymer compound of the second layer contains a structural unit having at least one crosslinking group selected from Group A of crosslinking groups, the content of the structural unit having at least one crosslinking group selected from Group A of crosslinking groups relative to the total amount of structural units contained in the polymer compound of the second layer is typically 0.1 to 100 mol %, and in order to achieve excellent stability and crosslinkability of the polymer compound of the second layer, it is preferably 1 to 99 mol %, more preferably 2 to 90 mol %, even more preferably 3 to 70 mol %, and particularly preferably 5 to 50 mol %. The structural unit having at least one type of crosslinking group selected from Group A of crosslinking groups may be contained in the polymer compound of the second layer in one type or in two or more types, preferably in two or more types, and more preferably in two types.

[0237] The structural unit having at least one crosslinking group selected from Group A of crosslinking groups is preferably a structural unit represented by formula (Z) or a structural unit represented by formula (Z'), since the external quantum efficiency of the light-emitting device of this embodiment is more excellent.

[0238] A structural unit represented by the formula (Z) n is usually an integer of 1 to 10, and is preferably an integer of 1 to 7, more preferably an integer of 1 to 4, even more preferably 1 or 2, and particularly preferably 2, since the external quantum efficiency of the light-emitting device of this embodiment is better. nA is usually an integer of 0 to 10, and is preferably an integer of 0 to 7, more preferably an integer of 0 to 4, even more preferably an integer of 0 to 2, and particularly preferably 0 or 1, since the external quantum efficiency of the light-emitting device of this embodiment is better.

[0239] Ar 3 Examples of the hydrocarbon group in Ar include an aromatic hydrocarbon group which may have a substituent and an aliphatic hydrocarbon group which may have a substituent. 3 The hydrocarbon group in the formula (I) includes groups in which a plurality of these groups are bonded.

[0240] Ar 3 Examples of the aliphatic hydrocarbon group in the formula (I) include groups in which n hydrogen atoms have been removed from an alkylene group or a cycloalkylene group, and preferably groups in which n hydrogen atoms have been removed from an alkylene group, and these groups may have a substituent.

[0241] Ar 3 The aromatic hydrocarbon group in the formula (I) includes a group in which n hydrogen atoms have been removed from an arylene group, and this group may have a substituent. Examples and preferred ranges of this arylene group include Ar Y1Examples of the arylene group and preferred ranges thereof are as follows:

[0242] Ar 3 The heterocyclic group in the formula (I) includes a group in which n hydrogen atoms have been removed from a divalent heterocyclic group, and this group may have a substituent. Examples and preferred ranges of this divalent heterocyclic group are described below in Ar Y1 Examples of the divalent heterocyclic group and preferred ranges thereof are as follows:

[0243] Ar 3 In the group in which at least one hydrocarbon group and at least one heterocyclic group are directly bonded, examples and preferred ranges of the hydrocarbon group and the heterocyclic group are respectively Ar 3 The examples and preferred ranges of the hydrocarbon group and heterocyclic group are the same as those in the above. Ar 3 Examples of the group in which at least one hydrocarbon group and at least one heterocyclic group are directly bonded include Ar Y1 and groups in which n hydrogen atoms have been removed from a group in which at least one arylene group and at least one divalent heterocyclic group are directly bonded to each other.

[0244] Ar 3 is preferably a hydrocarbon group or a heterocyclic group, more preferably a hydrocarbon group, and even more preferably an aromatic hydrocarbon group, since the external quantum efficiency of the light-emitting element of this embodiment is superior, and these groups may have a substituent.

[0245] L A Examples of the alkylene group represented by the formula (I) and a preferred range thereof include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, an octamethylene group, and groups in which some or all of the hydrogen atoms in these groups have been substituted with substituents.

[0246] L A Examples of the arylene group represented by the formula (I) and a preferred range thereof include Ar Y1The external quantum efficiency of the light-emitting device of this embodiment is superior, and therefore, L A The arylene group represented by the formula (I) is preferably a phenylene group or a fluorenediyl group, and these groups may have a substituent.

[0247] L A Examples and preferred ranges of the divalent heterocyclic group represented by Ar Y1 The examples and preferred ranges are the same as those of the divalent heterocyclic group represented by the following formula:

[0248] L A is preferably an arylene group or an alkylene group, more preferably a phenylene group, a fluorenediyl group or an alkylene group, and even more preferably an alkylene group, because this facilitates the synthesis of the polymer compound of the second layer, and these groups may have a substituent.

[0249] R' is preferably an aryl group or a monovalent heterocyclic group, more preferably an aryl group, and these groups may have a substituent. Examples and preferred ranges of the aryl group and monovalent heterocyclic group in R' are described below in Ar Y1 The examples and preferred ranges of the aryl group and monovalent heterocyclic group in the substituent that may be possessed by are the same as those of the aryl group and monovalent heterocyclic group.

[0250] Ar 3 , L A Examples of the substituents that may be possessed by the groups represented by R' and R' and their preferred ranges are described later in the section on Ar Y1 The examples and preferred ranges of the substituents that may be possessed by the group represented by the formula: Examples and preferred ranges of the crosslinking group for X are the same as the examples and preferred ranges of the crosslinking group selected from Group A of crosslinking groups in the polymer compound of the second layer.

[0251] The structural unit represented by formula (Z) has excellent stability and crosslinkability of the polymer compound of the second layer. Therefore, the content of the structural units is preferably 0.5 to 80 mol %, more preferably 3 to 65 mol %, and even more preferably 5 to 50 mol %, relative to the total amount of structural units contained in the polymer compound of the second layer. The polymer compound of the second layer may contain only one type of constitutional unit represented by formula (Z), or may contain two or more types.

[0252] A structural unit represented by the formula (Z') mA is usually an integer of 0 to 10, and is preferably an integer of 0 to 7, more preferably an integer of 0 to 4, even more preferably an integer of 0 to 2, particularly preferably 0 or 1, and especially preferably 0, since the external quantum efficiency of the light-emitting device of this embodiment is better. m is usually an integer of 0 to 10, and is preferably an integer of 0 to 7, more preferably an integer of 0 to 4, and even more preferably an integer of 0 to 2, since the external quantum efficiency of the light-emitting device of this embodiment is better. c is usually an integer of 0 to 10, and is preferably an integer of 0 to 5, more preferably an integer of 0 to 2, even more preferably 0 or 1, and particularly preferably 0, because this facilitates the production of the polymer compound of the second layer and provides a more excellent external quantum efficiency for the light-emitting device of this embodiment.

[0253] Ar 5 Examples and preferred ranges of the hydrocarbon group and heterocyclic group in 3 The examples and preferred ranges of the hydrocarbon group and heterocyclic group are the same as those in the above. Ar 5 Examples and preferred ranges of the group in which at least one hydrocarbon group and at least one heterocyclic group are directly bonded are: Ar 3 The examples and preferred ranges of the group in which at least one hydrocarbon group and at least one heterocyclic group are directly bonded are the same as those in the above. Ar 5is preferably a hydrocarbon group or a heterocyclic group, more preferably a hydrocarbon group, and even more preferably an aromatic hydrocarbon group, since the external quantum efficiency of the light-emitting element of this embodiment is superior, and these groups may have a substituent.

[0254] Ar 4 and Ar 6 is preferably an arylene group which may have a substituent, since the external quantum efficiency of the light-emitting device of this embodiment is superior. Ar 4 and Ar 6 Examples of the arylene group and a preferred range thereof are described later in the Ar X1 , Ar X2 , Ar X3 and Ar X4 The examples and preferred ranges of the arylene group are the same as those in the above. Ar 4 and Ar 6 Examples and preferred ranges of the divalent heterocyclic group in X1 , Ar X2 , Ar X3 and Ar X4 The examples and preferred ranges of the divalent heterocyclic group are the same as those in the above. Ar 4 ~Ar 6 Examples of the substituents that the group represented by the formula (I) may have and the preferred range of the substituents are described later in the Ar Y1 The examples and preferred ranges of the substituents that may be possessed by the group represented by the formula:

[0255] K A Examples and preferred ranges of L A The examples and preferred ranges are the same as those of the above. Examples and preferred ranges of R'' are the same as examples and preferred ranges of R'. Examples and preferred ranges of the crosslinking group for X′ are the same as the examples and preferred ranges of the crosslinking group selected from Group A of crosslinking groups represented by X. Examples and preferred ranges of the aryl group and the monovalent heterocyclic group in X' are described below in R X1 , R X2 and R X3The examples and preferred ranges of the aryl group and monovalent heterocyclic group in the above are the same as those in the above. X' is preferably a crosslinking group selected from Crosslinking Group Group A, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, more preferably a crosslinking group selected from Crosslinking Group Group A, an aryl group, or a monovalent heterocyclic group, and even more preferably a crosslinking group or aryl group selected from Crosslinking Group Group A, and these groups may have a substituent. Examples of the substituent that the group represented by X′ may have and the preferred range of the substituent are described later in the section Ar Y1 The examples and preferred ranges of the substituents that may be possessed by the group represented by the formula:

[0256] The structural unit represented by formula (Z') provides excellent stability to the polymer compound of the second layer and excellent crosslinkability to the polymer compound of the second layer, and therefore 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 structural units contained in the polymer compound of the second layer. The polymer compound of the second layer may contain only one type of constitutional unit represented by formula (Z'), or may contain two or more types.

[0257] Examples of the structural unit having at least one crosslinking group selected from Group A of crosslinking groups include structural units represented by the following formula: 2 represents a group represented by -O- or a group represented by -S-. 2 When there are multiple X's, they may be the same or different. A represents a crosslinking group selected from Group A of crosslinking groups. A When there are multiple X's, they may be the same or different. A The preferred range of is the same as the preferred range of the crosslinking group selected from Group A of crosslinking groups in the polymer compound of the second layer.

[0258] [ka]

[0259] [ka]

[0260] [ka]

[0261] [ka]

[0262] Other building blocks The polymer compound of the second layer is preferably a polymer compound containing at least one structural unit selected from the group consisting of structural units represented by formula (X) and structural units represented by formula (Y) (hereinafter also referred to as "polymer compound (2')"), since this provides a light-emitting device of this embodiment with better external quantum efficiency. The polymer compound (2') is a polymer having 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 having a crosslinking group. It is a molecular compound. The polymer compound (2') is preferably a polymer compound containing at least one structural unit selected from the group consisting of structural units represented by formula (X) and structural units represented by formula (Y), and a structural unit having at least one crosslinking group selected from group A of crosslinking groups, because this provides the light-emitting device of this embodiment with better external quantum efficiency. When the polymer compound (2') contains a structural unit having at least one crosslinking group selected from Group A of crosslinking groups, it is preferable that the structural unit having at least one crosslinking group selected from Group A of crosslinking groups is different from the structural unit represented by formula (X) and the structural unit represented by formula (Y). The polymer compound (2') preferably contains a structural unit represented by formula (Y), since this provides the light-emitting device of this embodiment with better external quantum efficiency. The polymer compound (2') preferably contains a structural unit represented by formula (X) because it has excellent hole transport properties. The polymer compound (2') preferably contains a structural unit represented by formula (X) and a structural unit represented by formula (Y), since this has excellent hole transport properties and the external quantum efficiency of the light-emitting device of this embodiment is superior.

[0263] [ka]

[0264] [In the formula, a X1 and a X2 each independently represents an integer of 0 or greater. Ar X1 and Ar X3 each independently represents an arylene group or a divalent heterocyclic group, and these groups may have a substituent. When a plurality of such substituents are present, 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 bonded. Ar X2 and Ar X4 are each independently an arylene group, a divalent heterocyclic group, or a divalent group in which at least one arylene group and at least one divalent heterocyclic group are directly bonded, and these groups may have a substituent. When a plurality of such substituents are present, 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 bonded. Ar X2 When a plurality of Ar are present, they may be the same or different. X4 When there are a plurality of groups, they may be the same or different. R X1 , R X2 and R X3 R each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may have a substituent. When a plurality of such substituents are present, 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 bonded. X2 When there are multiple R's, they may be the same or different.X3 If there are multiple It may be.]

[0265] [ka]

[0266] [In the formula, Ar Y1 represents an arylene group, a divalent heterocyclic group, or a divalent group in which at least one arylene group and at least one divalent heterocyclic group are directly bonded to each other, and these groups may have a substituent. When a plurality of such substituents are present, 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 bonded.

[0267] When the polymer compound (2') contains a structural unit represented by formula (X), the content of the structural unit represented by formula (X) is typically 0.1 to 99 mol % relative to the total amount of structural units contained in the polymer compound (2'). In order to improve the hole transport properties of the polymer compound (2') and to improve the external quantum efficiency of the light-emitting device of this embodiment, the content is preferably 1 to 90 mol %, more preferably 5 to 80 mol %, even more preferably 10 to 70 mol %, and particularly preferably 20 to 60 mol %. The polymer compound (2') may contain only one type of constitutional unit represented by formula (X), or may contain two or more types.

[0268] When the polymer compound (2') contains a structural unit represented by formula (Y), the content of the structural unit represented by formula (Y) is typically 0.1 to 99 mol % relative to the total amount of structural units contained in the polymer compound (2'). In order to improve the external quantum efficiency of the light-emitting device of this embodiment, the content 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 %. The polymer compound (2') may contain only one type of constitutional unit represented by formula (Y), or may contain two or more types.

[0269] A structural unit represented by the formula (Y) Ar Y1 The arylene group represented by the formula (I) is preferably a group obtained by removing two hydrogen atoms directly bonded to atoms constituting the ring from a monocyclic or bicyclic to hexacyclic aromatic hydrocarbon ring, more preferably a group obtained by removing two hydrogen atoms directly bonded to atoms constituting the ring from a monocyclic, bicyclic or tricyclic aromatic hydrocarbon ring, still more preferably a group obtained by removing two hydrogen atoms directly bonded to 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 atoms constituting the ring from benzene, phenanthrene, dihydrophenanthrene or fluorene, which may have a substituent, since the external quantum efficiency of the light-emitting element of this embodiment is more excellent.

[0270] Ar Y1 The divalent heterocyclic group represented by the formula (I) is preferably a group obtained by removing two hydrogen atoms directly bonded to atoms constituting the ring from a monocyclic or bicyclic to hexacyclic heterocycle, more preferably a group obtained by removing two hydrogen atoms directly bonded to atoms constituting the ring from a monocyclic, bicyclic or tricyclic heterocycle, still more preferably a group obtained by removing two hydrogen atoms directly bonded to atoms constituting the ring (preferably carbon atoms or nitrogen atoms, more preferably carbon atoms) from pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, carbazole, dibenzofuran, dibenzothiophene, phenoxazine, phenothiazine, 9,10-dihydroacridine or 5,10-dihydrophenazine, since the external quantum efficiency of the light-emitting element of this embodiment is more excellent. , carbazole, dibenzofuran, dibenzothiophene, phenoxazine, or phenothiazine, by removing two hydrogen atoms directly bonded to atoms constituting the ring (preferably carbon atoms or nitrogen atoms, more preferably carbon atoms), and these may have a substituent.

[0271] Ar Y1In the divalent group in which at least one arylene group and at least one divalent heterocyclic group are directly bonded, the preferred ranges of the arylene group and the divalent heterocyclic group are, respectively, Ar Y1 The preferred ranges are the same as those of the arylene group and divalent heterocyclic group represented by the following formula:

[0272] Ar Y1 In the above formula, examples of the "divalent group in which at least one arylene group and at least one divalent heterocyclic group are directly bonded" include groups represented by the following formulas, which may have a substituent.

[0273] [ka]

[0274] Ar Y1 is preferably an arylene group which may have a substituent, since the external quantum efficiency of the light-emitting device of this embodiment is superior.

[0275] Ar Y1 The substituent that the group represented by the formula (I) may have is preferably an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, an aryloxy group, a monovalent heterocyclic group, a substituted amino group, or a fluorine atom, more preferably an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, a monovalent heterocyclic group, or a substituted amino group, even more preferably an alkyl group, a cycloalkyl group, an aryl group, a monovalent heterocyclic group, or a substituted amino group, particularly preferably an alkyl group, a cycloalkyl group, or an aryl group, and especially preferably an alkyl group or an aryl group, and these groups may further have a substituent.

[0276] Ar Y1The aryl group in the substituent that the group represented by the formula (I) may have is preferably a group in which one hydrogen atom directly bonded to an atom constituting the ring has been removed from a monocyclic or bicyclic to hexacyclic aromatic hydrocarbon ring, more preferably a group in which one hydrogen atom directly bonded to an atom constituting the ring has been removed from a monocyclic, bicyclic or tricyclic aromatic hydrocarbon ring, even more preferably a group in which one hydrogen atom directly bonded to an atom constituting the ring has been removed from benzene, naphthalene, anthracene, phenanthrene, dihydrophenanthrene or fluorene, and particularly preferably a group in which one hydrogen atom directly bonded to an atom constituting the ring has been removed from benzene, phenanthrene, dihydrophenanthrene or fluorene, which may further have a substituent, because the external quantum efficiency of the light-emitting element of this embodiment is more excellent.

[0277] Ar Y1 The monovalent heterocyclic group in the substituent that may be included in the group represented by the formula (I) is preferably a group in which one hydrogen atom directly bonded to an atom constituting the ring is removed from a monocyclic or bicyclic to hexacyclic heterocycle, and more preferably a group in which one hydrogen atom directly bonded to an atom constituting the ring is removed from a monocyclic, bicyclic, or tricyclic heterocycle, because the external quantum efficiency of the light-emitting element of this embodiment is more excellent. and more preferably, a group in which one hydrogen atom directly bonded to an atom constituting the ring has been removed from pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, carbazole, dibenzofuran, dibenzothiophene, phenoxazine, phenothiazine, 9,10-dihydroacridine, or 5,10-dihydrophenazine, and particularly preferably, a group in which one hydrogen atom directly bonded to an atom constituting the ring has been removed from pyridine, diazabenzene, triazine, carbazole, dibenzofuran, dibenzothiophene, phenoxazine, or phenothiazine, and these may further have a substituent.

[0278] Ar Y1In the substituted amino group in the substituent that the group represented by the formula (I) may have, the substituent that the amino group has is preferably an aryl group or a monovalent heterocyclic group, more preferably an aryl group, and these groups may further have a substituent. Examples and preferred ranges of the aryl group and the monovalent heterocyclic group in the substituent that the amino group has are respectively given as Ar Y1 The examples and preferred ranges of the aryl group and monovalent heterocyclic group in the substituent that may be possessed by the group represented by the following formula are the same as those of the aryl group and monovalent heterocyclic group.

[0279] Ar Y1 The substituent that may be further possessed by the substituent that the group represented by the formula (I) may have is preferably an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, an aryloxy group, 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, still more preferably an alkyl group, a cycloalkyl group, or an aryl group, and particularly preferably an alkyl group or a cycloalkyl group. These groups may further have a substituent, but preferably do not have a further substituent. Ar Y1 Examples and preferred ranges of the aryl group, monovalent heterocyclic group and substituted amino group in the substituent that may be further substituted by the substituent that may be substituted by the group represented by the formula: Y1 The examples and preferred ranges of the aryl group, monovalent heterocyclic group and substituted amino group in the substituent that the group represented by the following formula may have are the same as those of the aryl group, monovalent heterocyclic group and substituted amino group in the substituent that the group represented by the following formula may have.

[0280] The structural unit represented by formula (Y) is preferably a structural unit represented by formula (Y-1) or formula (Y-2), since the external quantum efficiency of the light-emitting device of this embodiment is more excellent.

[0281] [ka]

[0282] [In the formula, R Y1represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, an aryloxy group, a monovalent heterocyclic group, a substituted amino group, or a fluorine atom, and these groups may have a substituent. When there are multiple such 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 bonded. When there are multiple R Y1 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 bonded. X Y1 is -C(R Y2 )2-, -C(R Y2 )=C(R Y2 )- or -C(R Y2 )2-C(R Y2 )2- represents a group represented by R Y2 is a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, an aryloxy group, a monovalent R represents a heterocyclic group, a substituted amino group, or a fluorine atom, and these groups may have a substituent. When there are multiple 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 bonded. Y2 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 bonded.

[0283] R Y1 is preferably a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, a monovalent heterocyclic group, or a substituted amino group, more preferably a hydrogen atom, an alkyl group, a cycloalkyl group, or an aryl group, and even more preferably a hydrogen atom or an alkyl group, and these groups may have a substituent. In formula (Y-1), R Y1 At least one of (preferably R Y1At least two of the above) are preferably an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, an aryloxy group, a monovalent heterocyclic group, a substituted amino group, or a fluorine atom, since the external quantum efficiency of the light-emitting element of this embodiment is more excellent, and are more preferably an alkyl group, a cycloalkyl group, an aryl group, a monovalent heterocyclic group, or a substituted amino group, and are even more preferably an alkyl group, a cycloalkyl group, or an aryl group, and are particularly preferably an alkyl group, and these groups may have a substituent.

[0284] X Y1 is preferably -C(R Y2 )2- or -C(R Y2 )2-C(R Y2 )2-, and more preferably, -C(R Y2 )2- is a group represented by the formula:

[0285] R Y2 is preferably a hydrogen atom, an alkyl group, or an aryl group, and more preferably an alkyl group or an aryl group, since the external quantum efficiency of the light-emitting device of this embodiment is superior, and these groups may have a substituent.

[0286] Examples of the structural unit represented by formula (Y) include structural units represented by the following formula: 1 represents a group represented by -N= or a group represented by -CH=. Z 1 When there are multiple Z's, they may be the same or different. 2 represents the same meaning as above.

[0287] [ka]

[0288] [ka]

[0289] [ka]

[0290] [ka]

[0291] A structural unit represented by formula (X) a X1 and a X2 is usually an integer of 0 to 10, and is preferably an integer of 0 to 5, more preferably an integer of 0 to 3, even more preferably an integer of 0 to 2, and particularly preferably 0 or 1, since the external quantum efficiency of the light-emitting device of this embodiment is more excellent.

[0292] R X1 , R X2 and R X3 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 a substituent.

[0293] R X1 , R X2 and R X3 Examples and preferred ranges of the aryl group and the monovalent heterocyclic group in Y1 The examples and preferred ranges of the aryl group and monovalent heterocyclic group in the substituent that may be possessed by the group represented by the following formula are the same as those of the aryl group and monovalent heterocyclic group.

[0294] Ar X1 , Ar X2 , Ar X3 and Ar X4 Examples and preferred ranges of the arylene group and the divalent heterocyclic group in Y1 The examples and preferred ranges of the arylene group and divalent heterocyclic group are the same as those in the above.

[0295] Ar X2 and Ar X4In the divalent group in which at least one arylene group and at least one divalent heterocyclic group are directly bonded, examples and preferred ranges of the arylene group and the divalent heterocyclic group are respectively Ar Y1 The examples and preferred ranges of the arylene group and divalent heterocyclic group are the same as those in the above. Ar X2 and Ar X4 In the above, examples of the divalent group in which at least one arylene group and at least one divalent heterocyclic group are directly bonded include Ar Y1 Examples of the divalent group include the same as the divalent group in which at least one arylene group and at least one divalent heterocyclic group are directly bonded to each other in the above formula.

[0296] Ar X1 , Ar X2 , Ar X3 and Ar X4 is preferably an arylene group which may have a substituent.

[0297] Ar X1 ~Ar X4 and R X1 ~R X3 Examples of the substituents that the group represented by the formula (I) may have and preferred The preferred range is Ar Y1 The examples and preferred ranges of the substituents that may be possessed by the group represented by the formula:

[0298] Examples of the structural unit represented by formula (X) include structural units represented by the following formula: 2 represents the same meaning as above.

[0299] [ka]

[0300] [ka]

[0301] [ka]

[0302] [ka]

[0303] Examples of the polymer compound for the second layer include polymer compounds P-1 to P-11 shown in Table 1. Here, "other" refers to structural units other than the structural units represented by formula (Z), the structural units represented by formula (Z'), the structural units represented by formula (X) and the structural units represented by formula (Y).

[0304] [Table 1]

[0305] The polymer compound of the second layer may be a block copolymer, a random copolymer, an alternating copolymer, a graft copolymer, or other form, but is preferably a copolymer obtained by copolymerizing multiple types of raw material monomers. The number average molecular weight of the polymer compound of the second layer in terms of polystyrene is preferably 5×10 3 ~1×10 6 and more preferably 1×10 4 ~5×10 5 and more preferably 2 × 10 4 ~1×10 5 The weight average molecular weight of the polymer compound of the second layer in terms of polystyrene is preferably 1×10 4 ~2×10 6 and 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 is.

[0306] Manufacturing method of the polymer compound of the second layer The polymer compound of the second layer can be produced using a known polymerization method described in, for example, Chem. Rev., Vol. 109, pp. 897-1091 (2009), and examples of such methods include polymerization by coupling reactions using transition metal catalysts, such as Suzuki reaction, Yamamoto reaction, Buchwald reaction, Stille reaction, Negishi reaction, and Kumada reaction. In the above polymerization method, examples of the method for charging the monomers include a method in which the entire amount of the monomers is charged into the reaction system all at once, a method in which a part of the monomers is charged and reacted, and then the remaining monomers are charged all at once, continuously or in portions, and a method in which the monomers are charged continuously or in portions. Examples of the transition metal catalyst include a palladium catalyst and a nickel catalyst. Post-treatment of the polymerization reaction can be carried out by any of the known methods, such as removing water-soluble impurities by separation, adding the reaction solution after the polymerization reaction 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 removed by, for example, recrystallization, reprecipitation, continuous extraction using a Soxhlet extractor, column chromatography, or the like. The product can be purified by conventional methods such as chromatography.

[0307] [(Y1 x 1000) / X1 value] The value of (Y1×1000) / X1 in the polymer compound of the second layer can be determined, for example, by the following method. First, for each structural unit of the polymer compound, the molar ratio C of that structural unit to the total moles of all structural units is multiplied by the molecular weight M of that structural unit to determine x, and the molar ratio C is multiplied by the number n of crosslinking groups possessed by that structural unit to determine y. Next, the sum of the x values ​​calculated for each structural unit is designated X1, and the sum of the y values ​​calculated for each structural unit is designated Y1. That is, when the second layer contains only one polymer compound, the value of (Y1 × 1000) / X1 is the value of (Y1 × 1000) / X1 of the polymer compound in the second layer. Therefore, the value of (Y1 × 1000) / X1 is approximately equal to the average number of crosslinking groups per 1000 molecular weight of the polymer compound in the second layer, and can be effectively used as an indicator of the average number of crosslinking groups in the polymer compound in the second layer.

[0308] A specific method for calculating the average number of crosslinking groups will be explained based on the polymer compound HTL-1 used in Example D1. Polymer compound HTL-1 has structural units derived from compounds M7, M6, and M5. The molar ratio of each structural unit to the total moles of all structural units is 0.45 for the structural unit derived from compound M7, 0.05 for the structural unit derived from compound M6, and 0.50 for the structural unit derived from compound M5. The molecular weight of the structural unit derived from compound M7 is 776.45, the molecular weight of the structural unit derived from compound M6 is 240.20, and the molecular weight of the structural unit derived from compound M5 is 750.51. The number of crosslinking groups possessed by the structural unit derived from compound M7 is 2, the number of crosslinking groups possessed by the structural unit derived from compound M6 is 2, and the number of crosslinking groups possessed by the structural unit derived from compound M5 is 0. From these numerical values, X1, Y1, and (Y1 × 1000) / X1 can be calculated as follows.

[0309] X1=(0.45×776.45)+(0.05×240.20)+(0.50×750.51)=736.67 Y1=(0.45×2)+(0.05×2)+(0.50×0)=1.00 (Y1×1000) / X1=(1.00×1000) / 736.67=1.36

[0310] When two or more polymeric compounds are contained, the value of (Y1×1000) / X1 is calculated based on the structural units constituting each polymeric compound. The value of (Y1×1000) / X1 is calculated for each polymeric compound, and the value of (Y1×1000) / X1 is calculated from the blend ratio of each polymeric compound. That is, when the second layer contains two or more polymeric compounds, the value of (Y1×1000) / X1 can be calculated by defining X1 as the sum of the molecular weights of all structural units constituting all polymeric compounds contained in the second layer, and defining Y1 as the sum of the number of crosslinking groups possessed by all structural units constituting all polymeric compounds contained in the second layer.

[0311] A specific calculation method will be explained for the case of blending polymer compound HTL-C1 and polymer compound HTL-C2 in a 50:50 ratio in Comparative Example CD1.

[0312] Polymer compound HTL-C1 has structural units derived from compounds M1, M5, M6, and M7. In polymer compound HTL-2, the ratio of structural units derived from compound M1 to the total moles of all structural units is 0.40, 0.50, 0.05, and 0.05, respectively. The molecular weight of the structural unit derived from compound M1 is 244.42, the molecular weight of the structural unit derived from compound M5 is 751.11, the molecular weight of the structural unit derived from compound M6 is 240.39, and the molecular weight of the structural unit derived from compound M7 is 0.05. is 777.11. The number of crosslinking groups possessed by the structural unit derived from compound M1 is 0, the number of crosslinking groups possessed by the structural unit derived from compound M5 is 0, the number of crosslinking groups possessed by the monomer derived from compound M6 is 2, and the number of crosslinking groups possessed by the structural unit derived from compound M7 is 2. Therefore, the value of (Y1 × 1000) / X1 calculated using the above-mentioned method for polymer compound HTL-C1 is 0.38.

[0313] The polymer compound HTL-C2 has structural units derived from compounds M1 and M5. In the polymer compound HTL-C1, the ratio of structural units derived from compound M1 to the total molar amount of all structural units is 0.50, and the ratio of structural units derived from compound M5 to the total molar amount of all structural units is 0.50. Therefore, the value of (Y1×1000) / X1 calculated using the above method for the polymer compound HTL-C2 is 0.

[0314] In Comparative Example CD1, the polymer compound HTL-C1 and the polymer compound HTL-C2 are blended in a ratio of 50:50. Therefore, in Comparative Example CD4, the value of (Y1×1000) / X1 can be calculated as 0.19 using the following formula. 0.38×0.5+0×0.5=0.19

[0315] As described above, the value of (Y1×1000) / X1 can be calculated by taking X1 as the sum of the molecular weights of all structural units constituting all of the polymer compounds contained in the second layer and Y1 as the sum of the number of crosslinking groups possessed by all structural units constituting all of the polymer compounds contained in the second layer. When the second layer contains only one type of polymer compound, the value of (Y1×1000) / X1 is the value of (Y1×1000) / X1 of the polymer compound in the second layer. When the second layer contains two or more types of polymer compounds, the value can be calculated from the blend ratio of the structural units constituting each polymer compound contained in the second layer and the blend ratio of each polymer compound contained in the second layer.

[0316] The value of (Y1×1000) / X1 is usually 0.25 or more, and since the external quantum efficiency of the light-emitting element of this embodiment is better, it is preferably 0.30 or more, and may be 0.35 or more, 0.40 or more, 0.45 or more, 0.50 or more, 0.55 or more, 0.60 or more, or 0.65 or more.

[0317] The value of (Y1×1000) / X1 is usually 10.0 or less, and may be 7.0 or less, 5.0 or less, 4.0 or less, 3.0 or less, 2.0 or less, 1.8 or less, or 1.7 or less. Since the external quantum efficiency of the light-emitting element of this embodiment is better, it is preferably 1.6 or less, more preferably 1.5 or less, and even more preferably 1.4 or less.

[0318] [Second Composition] The second layer may be a layer containing a composition (hereinafter also referred to as "second composition") containing a crosslinked polymer compound of the second layer and at least one material selected from the group consisting of a hole transport material, a hole injection material, an electron transport material, an electron injection material, a light emitting material, and an antioxidant. In the second layer, the hole transport material, the hole injection material, the electron transport material, the electron injection material, and the light emitting material are different from the crosslinked polymer compound of the second layer. The second composition may contain one or more of the crosslinked polymer compound of the second layer, the hole transport material, the hole injection material, the electron transport material, the electron injection material, the light-emitting material, and the antioxidant. Examples and preferred ranges of the hole transport material, hole injection material, electron transport material, electron injection material, light-emitting material, and antioxidant contained in the second composition are the same as the examples and preferred ranges of the hole transport material, hole injection material, electron transport material, electron injection material, light-emitting material, and antioxidant contained in the first composition.

[0319] In the second composition, the total content of the crosslinked polymer compound, hole transport material, hole injection material, electron transport material, electron injection material, light-emitting material, and antioxidant in the second layer may be within a range that allows the second composition to function. The total content of the crosslinked polymer compound, hole transport material, hole injection material, electron transport material, electron injection material, light-emitting material, and antioxidant in the second layer may be, for example, 1 to 100 mass%, 10 to 100 mass%, 30 to 100 mass%, or more preferably 50 to 100 mass%, 70 to 100 mass%, or 90 to 100 mass%, based on the total amount of the second composition. In the second composition, the content of each of the hole transport material, hole injection material, electron transport material, electron injection material, and light emitting material is typically 1 to 1,000 parts by mass, relative to 100 parts by mass of the crosslinked polymer compound in the second layer. In the second composition, the content of the antioxidant is typically 0.001 to 10 parts by mass, relative to 100 parts by mass of the crosslinked polymer compound in the second layer.

[0320] (Second ink) The second layer can be formed, for example, using a composition containing the polymer compound of the second layer and a solvent (hereinafter also referred to as "second ink"). The second ink can be suitably used in the wet method described in the section on the first ink. The preferred range of viscosity of the second ink is the same as the preferred range of viscosity of the first ink. Examples and preferred ranges of solvents contained in the second ink are the same as the examples and preferred ranges of solvents contained in the first ink.

[0321] In the second ink, the content of the solvent is usually 1,000 to 100,000 parts by mass, assuming that the content of the polymer compound in the second layer is 100 parts by mass.

[0322] The second ink may further contain at least one 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. Examples and preferred ranges of the hole transport material, electron transport material, hole injection material, electron injection material, light-emitting material, and antioxidant that may further be contained in the second ink are the same as the examples and preferred ranges of the hole transport material, electron transport material, hole injection material, electron injection material, light-emitting material, and antioxidant contained in the second composition.

[0323] The content of each of the hole transport material, electron transport material, hole injection material, electron injection material, and light emitting material, which may be further contained in the second ink, is typically 1 to 1,000 parts by mass, based on 100 parts by mass of the polymer compound in the second layer. The content of the antioxidant, which may be further contained in the second ink, is typically 0.001 to 10 parts by mass, based on 100 parts by mass of the polymer compound in the second layer.

[0324] <Light-emitting element> 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 device of this embodiment may further include layers other than the anode, the cathode, the first layer, and the second layer.

[0325] The first layer is usually a light-emitting layer (hereinafter referred to as "first light-emitting layer"). The second layer is usually a hole injection layer, a hole transport layer, an emitting layer (i.e., an emitting layer separate from the first emitting layer, hereinafter referred to as the "second emitting layer"), or an electron transport layer, preferably a hole injection layer, a hole transport layer, or a second emitting layer, more preferably a hole injection layer or a hole transport layer, and even more preferably a hole transport layer.

[0326] The first layer and the second layer are preferably adjacent to each other, as this provides a better external quantum efficiency for the light-emitting device of this embodiment. The second layer is preferably a layer provided between the anode and the first layer, since the external quantum efficiency of the light-emitting element of this embodiment is superior, more preferably a hole injection layer, a hole transport layer, or a second light-emitting layer provided between the anode and the first layer, still more preferably a hole injection layer or a 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.

[0327] When the second layer is a second light-emitting layer provided between the anode and the first layer, the external quantum efficiency of the light-emitting device of this embodiment is more excellent, so it is preferable to further include at least one layer selected from a hole injection layer and a hole transport layer between the anode and the second layer.Furthermore, when the second layer is a second light-emitting layer provided between the anode and the first layer, the external quantum efficiency of the light-emitting device of this embodiment is more excellent, so it is preferable to further include at least one layer selected from an electron injection layer and an electron transport layer between the cathode and the first layer.

[0328] When the second layer is a second light-emitting layer provided between the cathode and the first layer, the external quantum efficiency of the light-emitting device of this embodiment is more excellent, so it is preferable to further include at least one layer selected from a hole injection layer and a hole transport layer between the anode and the first layer. Also, when the second layer is a second light-emitting layer provided between the cathode and the first layer, the external quantum efficiency of the light-emitting device of this embodiment is more excellent, so it is preferable to further include at least one layer selected from an electron injection layer and an electron transport layer between the cathode and the second layer.

[0329] When the second layer is a hole transport layer provided between the anode and the first layer, the external quantum efficiency of the light-emitting device of this embodiment is more excellent, so it is preferable to further include a hole injection layer between the anode and the second layer. Also, when the second layer is a hole transport layer provided between the anode and the first layer, the external quantum efficiency of the light-emitting device of this embodiment is more excellent, so it is preferable to further include at least one layer of an electron injection layer and an electron transport layer between the cathode and the first layer.

[0330] When the second layer is a hole injection layer provided between the anode and the first layer, the external quantum efficiency of the light-emitting device of this embodiment is more excellent, so it is preferable to further include a hole transport layer between the first layer and the second layer. Also, when the second layer is a hole injection layer provided between the anode and the first layer, the external quantum efficiency of the light-emitting device of this embodiment is more excellent, so it is preferable to further include at least one layer of an electron injection layer and an electron transport layer between the cathode and the first layer.

[0331] When the second layer is an electron transport layer provided between the cathode and the first layer, the external quantum efficiency of the light-emitting device of this embodiment is more excellent, so it is preferable to further include at least one layer of a hole injection layer and a hole transport layer between the anode and the first layer. Also, when the second layer is an electron transport layer provided between the cathode and the first layer, the external quantum efficiency of the light-emitting device of this embodiment is more excellent, so it is preferable to further include an electron injection layer between the cathode and the second layer.

[0332] Specific examples of the layer structure of the light-emitting device of this embodiment include layer structures represented by (D1) to (D18). The light-emitting device of this embodiment usually has a substrate, but may have an anode layer stacked on the substrate, or a cathode layer stacked on the substrate.

[0333] (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 emitting layer (first layer) / second 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

[0334] In the above (D1) to (D18), " / " means that the layers before and after it are 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 adjacent to each other.

[0335] In the light-emitting element of this embodiment, two or more layers of each of the anode, hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer, and cathode may be provided, if necessary. When a plurality of anodes, hole injection layers, hole transport layers, light-emitting layers, electron transport layers, electron injection layers, and cathodes are present, the materials constituting them may be the same or different. The thickness of each of the anode, hole injection layer, hole transport layer, first layer, second layer, light emitting layer, electron transport layer, electron injection layer, and cathode is usually 1 nm to 1 μm, preferably 2 nm to 500 nm, and more preferably 5 nm to 150 nm. In the light-emitting device of this embodiment, the order, number and thickness of the layers to be stacked may be adjusted taking into consideration the external quantum efficiency and luminance life of the light-emitting device.

[0336] [First light-emitting layer] The first light-emitting layer is usually the first layer.

[0337] [Second light-emitting layer] The second light-emitting layer is usually a layer containing a second layer or a light-emitting material, and 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 materials that may be contained in the second composition described above. The light-emitting material contained in the second light-emitting layer may be one type alone or two or more types. When the light-emitting element of this embodiment has a second light-emitting layer, and the hole injection layer described below, the hole transport layer described below, and the electron transport layer described below are not the second layer, it is preferable that the second light-emitting layer is the second layer.

[0338] [Hole transport layer] The hole transport layer is the second layer or a layer containing a hole transport material, preferably the second layer. When the hole transport layer is a layer containing a hole transport material, examples of the hole transport material include the hole transport materials that may be contained in the second composition. The hole transport material contained in the hole transport layer may be one type alone or two or more types. When the light-emitting element of this embodiment has a hole transport layer and the hole injection layer described below, the second light-emitting layer described above, and the electron transport layer described below are not the second layer, it is preferable that the hole transport layer be the second layer.

[0339] [Electron transport layer] The electron transport layer is the 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 materials that may be contained in the second composition described above. The electron transport material contained in the electron transport layer may be one type alone or two or more types. When the light-emitting element of this embodiment has an electron transport layer, and the hole injection layer described below, the second light-emitting layer described above, and the hole transport layer described above are not the second layer, it is preferable that the electron transport layer be the second layer.

[0340] [Hole injection layer] The hole injection layer is the 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, examples of the hole injection material contained in the hole injection layer include the hole injection material that may be contained in the second composition described above. The hole injection layer may contain one type of hole injection material alone, or two or more types of hole injection materials. When the light-emitting element of this embodiment has a hole injection layer, and the second light-emitting layer, the hole transport layer, and the electron transport layer are not the second layer, it is preferable that the hole injection layer is the second layer.

[0341] [Electron injection layer] The electron injection layer is a layer containing an electron injection material. Examples of the electron injection material contained in the electron injection layer include the electron injection material that may be contained in the second composition described above. The electron injection layer may contain one type of electron injection material alone, or two or more types of electron injection materials.

[0342] [Substrate / Electrode] The substrate in the light-emitting element is preferably a substrate that is not chemically changed during the formation of the electrodes and the organic layers. The substrate may be made of a material such as glass, plastic, silicon, etc. When an opaque substrate is used, it is preferable that the electrode farthest from the substrate is transparent or translucent.

[0343] Examples of materials for the anode include conductive metal oxides and translucent metals, and preferred are indium oxide, zinc oxide, and tin oxide; conductive compounds such as indium tin oxide (ITO) and indium zinc oxide; silver-palladium-copper composite (APC); NESA, gold, platinum, silver, and copper.

[0344] Cathode materials include, for example, 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 alloy, magnesium-indium alloy, magnesium-aluminum alloy, indium-silver alloy, lithium-aluminum alloy, lithium-magnesium alloy, lithium-indium alloy, and calcium-aluminum alloy.

[0345] In the light-emitting device of this embodiment, at least one of the anode and the cathode is usually transparent or semi-transparent, and it is preferable that the anode is transparent or semi-transparent.

[0346] Examples of methods for forming the anode and cathode include vacuum deposition, sputtering, ion plating, plating, and lamination.

[0347] [Method of manufacturing light-emitting element] In the method for manufacturing a light-emitting element of this embodiment, the first layer, the second layer, and layers other than the first and second layers can be formed by dry methods such as vacuum deposition and the wet methods described in the section on the first ink when a low-molecular-weight compound is used, and by wet methods such as the wet methods described in the section on the first ink when a high-molecular-weight compound is used. In the method for manufacturing a light-emitting element of this embodiment, the first layer, the second layer, and layers other than the first and second layers can be formed by wet methods described in the section on the first ink using the various inks and inks containing various materials described above, or by dry methods such as vacuum deposition.

[0348] In the method for producing a light-emitting device of this embodiment, a layer containing a crosslinked polymer compound of the second layer (e.g., the second layer) can be formed, for example, by forming a layer containing a polymer compound of the second layer, and then heating or irradiating the layer with light (preferably heating) to crosslink the polymer compound of the second layer contained in the layer. When the polymer compound of the second layer is contained in the second layer in a crosslinked state (crosslinked polymer compound of the second layer), the layer is substantially insolubilized in a solvent. Therefore, a layer containing a crosslinked polymer compound of the second layer can be suitably used for laminating layers in the production of a light-emitting device of this embodiment.

[0349] From the above viewpoints, in the method for producing a light-emitting device of this embodiment, the step of forming the second layer preferably includes a step of forming a layer containing a polymer compound of the second layer, and then crosslinking the polymer compound of the second layer contained in the layer to form a second layer containing a crosslinked product of the polymer compound of the second layer. In the step of forming the second layer, the method of crosslinking the polymer compound of the second layer is preferably a method of crosslinking by heating or light irradiation, since this facilitates production of the light-emitting device of this embodiment, and more preferably a method of crosslinking by heating.

[0350] The heating temperature for crosslinking is usually 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. The time is preferably 1 minute to 120 minutes, and more preferably 10 minutes to 60 minutes. The type of light used for the light irradiation is, for example, ultraviolet light, near ultraviolet light, or visible light.

[0351] The process for forming the second layer may be, for example, a method in which a layer is formed by a wet method using a second ink, and then the polymer compound of the second layer contained in the layer is crosslinked to form the second layer.

[0352] Methods for analyzing components contained in the first layer, the second layer, or layers other than the first and second layers include, for example, 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. The first layer, the second layer, or a layer other than the first and second layers can be subjected to solid-liquid extraction using an organic solvent such as toluene, xylene, chloroform, or tetrahydrofuran to separate the first layer, the second layer, or a layer other than the first and second layers into a component that is substantially insoluble in the organic solvent (insoluble component) and a component that is soluble in the organic solvent (soluble component). The insoluble component can be analyzed by infrared spectroscopy or nuclear magnetic resonance spectroscopy, and the soluble component can be analyzed by nuclear magnetic resonance spectroscopy or mass spectrometry.

[0353] The light-emitting element of this embodiment can be manufactured, for example, by sequentially stacking each layer on a substrate. Specifically, the light-emitting element can be manufactured by providing an anode on a substrate, then providing layers such as a hole injection layer and a hole transport layer thereon, then providing a light-emitting layer thereon, then providing layers such as an electron transport layer and an electron injection layer thereon, and then stacking a cathode on top of that. As another manufacturing method, the light-emitting element can be manufactured by providing a cathode on a substrate, then 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 thereon, and then stacking an anode on top of that. As yet another manufacturing method, the light-emitting element can be manufactured by opposing and bonding an anode-side substrate having an anode or each layer stacked on the anode and a cathode or each layer stacked on the cathode.

[0354] In the manufacture of the light-emitting element of this embodiment, when the materials used to form the hole injection layer, the light-emitting layer, the hole transport layer, the electron transport layer, and the electron injection layer are each soluble in a solvent used to form the hole injection layer, the light-emitting layer, the hole transport layer, the electron transport layer, and a layer adjacent to the electron injection layer, it is preferable to prevent the materials from dissolving in the solvent. Methods for preventing material dissolution include (i) using a material having a crosslinking group, or (ii) providing a difference in solubility in the solvent between adjacent layers. In the method (i), a layer is formed using a material having a crosslinking group, and then the crosslinking group is crosslinked to insolubilize the layer. In the method (ii), for example, when an electron transport layer is laminated on the light-emitting layer by utilizing the difference in solubility, the electron transport layer can be laminated on the light-emitting layer by using an ink that is less soluble in the light-emitting layer.

[0355] [Application] The light-emitting element of this embodiment can be suitably used as a light source for backlighting of a liquid crystal display device, a light source for illumination, an organic EL light source, and a display device for a computer, a television, a mobile terminal, etc. (for example, an organic EL display and an organic EL television). [Example]

[0356] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0357] In the examples, the number average molecular weight (Mn) of the polymer compound in terms of polystyrene and the polystyrene equivalent The weight average molecular weight (Mw) in terms of polyethylene was determined by size exclusion chromatography (SEC) using tetrahydrofuran as the mobile phase. The measurement conditions for SEC are as follows: The polymer compound to be measured was dissolved in tetrahydrofuran at a concentration of approximately 0.05% by mass, and 10 μL of the solution was injected into the SEC. The mobile phase was run at a flow rate of 2.0 mL / min. The column used was a PLgel MIXED-B (manufactured by Polymer Laboratories). The detector used was a UV-VIS detector (manufactured by Shimadzu Corporation, product name: SPD-10Avp).

[0358] In the examples, the energy levels of the lowest excited singlet state (S1) and lowest excited triplet state (T1) of the compounds were calculated using the quantum chemistry calculation program Gaussian09. As basis functions, 6-31G* was used for atoms other than iridium, and LANL2DZ was used for the iridium atom. The ground state structure of the compound was optimized using density functional theory, and the energy levels of the lowest excited singlet state (S1) and lowest excited triplet state (T1) were calculated using time-dependent density functional theory using the optimized structure. For metal complexes, linear alkyl groups with 5 or more carbon atoms (excluding the carbon atoms of substituents) were replaced with alkyl groups with 3 or fewer carbon atoms for calculations.

[0359] <Synthesis Example M> Synthesis of compounds M1 to M15 Compound M1 was synthesized according to the method described in JP-A-2010-189630. Compound M2 was synthesized according to the method described in JP-A-2008-106241. Compound M3 was synthesized according to the method described in JP-A-2010-215886. Compound M4 was synthesized according to the method described in WO 2005 / 049546. Compound M5 was synthesized according to the method described in WO 2013 / 146806. Compound M6 was synthesized according to the method described in WO 2015 / 145871. Compound M7 was synthesized according to the method described in WO 2002 / 045184. Compound M8 was synthesized according to the method described in JP 2011-174062 A. Compound M9 was synthesized according to the method described in WO 2016 / 031639. Compound M10 was synthesized according to the method described in WO 2016 / 031639. Compound M11 was synthesized according to the method described in JP-A-2011-174062. Compound M12 was synthesized according to the method described in JP-A-2008-106241. Compound M13 was synthesized according to the method described in WO 2016 / 031639. Compound M14 was synthesized according to the method described in WO 2016 / 031639. Compound M15 was synthesized according to the method described in WO 2016 / 031639.

[0360] [ka]

[0361] <Synthesis Example HTL> Synthesis of polymer compounds HTL-1 to HTL-9 and HTL-C1 to HTL-C4 Polymer compounds (copolymers) HTL-1 to HTL-9 and HTL-C1 to HTL-C4 were synthesized using the types and molar ratios of compounds shown in Table 2 by the synthesis methods shown in the same table. The Mn, Mw, and (Y1×1000) / X1 values ​​(average number of crosslinking groups) of the obtained polymer compounds are as shown in Table 2.

[0362] [Table 2]

[0363] <Synthesis Example R> Synthesis of metal complexes R1 to R4 and RC1 Metal complex R1 was synthesized according to the method described in WO 2015 / 105014. Metal complex R2 was synthesized according to the method described in WO 2021 / 019884. Metal complex R3 was synthesized according to the method described in WO 2016 / 043097. Metal complex R4 was synthesized according to the method described in WO 2016 / 043097. Metal complex RC1 was synthesized according to the method described in JP-A-2006-188673.

[0364] [ka]

[0365] Using the structures shown in Table 3, the energy levels of the lowest excited singlet state (S1) and the lowest excited triplet state (T1) of the metal complexes R1 to R4 and RC1 were calculated. The lowest excited singlet state (S1) and lowest excited triplet state (S2) of the obtained metal complexes R1-R4 and RC1 were The energy levels of the singlet state (T1) are shown in Table 3.

[0366] [Table 3]

[0367] [ka]

[0368] <Synthesis Example B> Synthesis of metal complexes B1 to B3, BC1 and BC2 Metal complexes B1 to B3 and BC2 were synthesized according to the method described in WO 2019 / 065389. Metal complex BC1 was synthesized according to the method described in WO 2019 / 065389.

[0369] [ka]

[0370] Using the structures shown in Table 4, the energy levels of the lowest excited singlet state (S1) and the lowest excited triplet state (T1) of metal complexes B1 to B3, BC1, and BC2 were calculated. Table 4 shows the energy levels of the lowest excited singlet state (S1) and the lowest excited triplet state (T1) of the obtained metal complexes B1 to B3, BC1, and BC2.

[0371] [Table 4]

[0372] [ka]

[0373] <Synthesis Example H> Synthesis and acquisition of compounds H1 to H7 Compounds H1, H3, H4, H6 and H7 were manufactured by Luminescence Technology. Compound H2 was synthesized according to the method described in JP-A-2010-189630. Compound H5 was manufactured by BLD Pharmatech.

[0374] [ka]

[0375] Table 5 shows the results of calculation of the energy levels of the lowest excited singlet state (S1) and the lowest excited triplet state (T1) of compounds H1 to H7.

[0376] [Table 5]

[0377] Example D1 Fabrication and Evaluation of Light-Emitting Device D1 (Formation of anode and hole injection layer) The anode was formed by applying an ITO film with a thickness of 45 nm to a glass substrate by sputtering. A hole injection material, ND-3202 (manufactured by Nissan Chemical Industries, Ltd.), was formed on the anode by spin coating to a thickness of 65 nm, and the film was heated on a hot plate at 240°C for 15 minutes in an air atmosphere to form a hole injection layer.

[0378] (Formation of the second layer) The polymer compound HTL-1 was dissolved in xylene at a concentration of 0.7% by mass. The resulting xylene solution was spin-coated onto the hole injection layer to form a 20 nm thick film. The second layer was then heated on a hot plate at 180°C for 60 minutes under a nitrogen gas atmosphere. This heating process crosslinked the polymer compound HTL-1.

[0379] (Formation of the first layer) Compound H1 and metal complex R1 (compound H1 / metal complex R1=92.5% by mass / 7.5% by mass) were dissolved in xylene so that the total concentration was 2% by mass. The resulting xylene solution was spin-coated onto the second layer to form a film with a thickness of 80 nm, and heated at 130°C for 10 minutes in a nitrogen gas atmosphere to form a first layer.

[0380] (Cathode formation) The substrate on which the first layer was formed was placed in a deposition machine. -4 After reducing the pressure to 100 Pa or less, sodium fluoride was deposited on the first layer to a thickness of about 4 nm, and then aluminum was deposited on the sodium fluoride layer to a thickness of about 80 nm to form a cathode. The substrate on which the cathode was formed was then sealed with a glass substrate to produce light-emitting device D1.

[0381] (Evaluation of light-emitting elements) EL light emission was observed when a voltage was applied to the light-emitting element D1. 2 The external quantum efficiency and CIE chromaticity coordinates were measured.

[0382] <Examples D2 and D3, Comparative Example CD2> Fabrication and Evaluation of Light-Emitting Devices D2, D3, and CD2 Light-emitting devices D2, D3, and CD2 were fabricated in the same manner as in Example D1, except that the materials listed in Table 6 were used instead of the polymer compound HTL-1 in Example D1 (formation of the second layer). EL emission was observed by applying a voltage to the light-emitting devices D2, D3, and CD2. When the current density of the light-emitting devices D2, D3, and CD2 was 3 mA / cm 2 The external quantum efficiency and CIE chromaticity coordinates were measured.

[0383] <Comparative Example CD1> Fabrication and Evaluation of Light-Emitting Device CD1 A light-emitting device CD1 was produced in the same manner as in Example D1, except that "polymer compound HTL-C1 and polymer compound HTL-C2 (polymer compound HTL-C1 / polymer compound HTL-C2 = 50% by mass / 50% by mass)" were used instead of "polymer compound HTL-1" in Example D1 (formation of the second layer). EL emission was observed by applying a voltage to the light-emitting device CD1. 2 The external quantum efficiency and CIE chromaticity coordinates were measured.

[0384] The results of Examples D1 to D3 and Comparative Examples CD1 and CD2 are shown in Table 6. The external quantum efficiency of the light-emitting devices D1 to D3, CD1, and CD2 is shown as a relative value when the external quantum efficiency of the light-emitting device CD1 is set to 1.0.

[0385] [Table 6]

[0386] Example D4 and Comparative Example CD3 Fabrication and Evaluation of Light-Emitting Devices D4 and CD3 Light-emitting devices D4 and CD3 were fabricated in the same manner as in Example D1, except that the materials listed in Table 7 were used instead of the "polymer compound HTL-1" in Example D1 (formation of the second layer). EL emission was observed by applying a voltage to the light-emitting devices D4 and CD3. The current density of the light-emitting devices D4 and CD3 was 3 mA / cm. 2 The external quantum efficiency and CIE chromaticity coordinates were measured.

[0387] The results of Example D4 and Comparative Example CD3 are shown in Table 7. The external quantum efficiency of the light-emitting device D4 and CD3 are shown as relative values ​​when the external quantum efficiency of the light-emitting device CD3 is set to 1.0.

[0388] [Table 7]

[0389] Example D5 and Comparative Example CD4 Fabrication and Evaluation of Light-Emitting Devices D5 and CD4 Light-emitting devices D5 and CD4 were fabricated in the same manner as in Example D1, except that the materials listed in Table 8 were used instead of the polymer compound HTL-1 used in Example D1 (forming the second layer), and that the compound H2 was used instead of the compound H1 used in Example D1 (forming the first layer). EL emission was observed when a voltage was applied to the light-emitting devices D5 and CD4. The current density of the light-emitting devices D5 and CD4 was 3 mA / cm. 2 The external quantum efficiency and CIE chromaticity coordinates were measured.

[0390] The results of Example D5 and Comparative Example CD4 are shown in Table 8. The external quantum efficiency of the light-emitting device D5 and CD4 is shown as a relative value when the external quantum efficiency of the light-emitting device CD4 is set to 1.0.

[0391] [Table 8]

[0392] Example D6 Fabrication and Evaluation of Light-Emitting Device D6 (Formation of anode and hole injection layer) An ITO film was formed on a glass substrate by sputtering to a thickness of 45 nm to form an anode. A hole injection material, ND-3202 (manufactured by Nissan Chemical Co., Ltd.), was spin-coated onto the anode to form a film of 35 nm thickness. The film was then heated on a hot plate at 240°C for 15 minutes in an air atmosphere to form a hole injection layer.

[0393] (Formation of the second layer) The polymer compound HTL-1 was dissolved in xylene at a concentration of 0.7% by mass. The resulting xylene solution was spin-coated onto the hole injection layer to form a 20 nm thick film. The second layer was then heated on a hot plate at 180°C for 60 minutes under a nitrogen gas atmosphere. This heating process crosslinked the polymer compound HTL-1.

[0394] (Formation of the first layer) Compound H2 and metal complex B1 (compound H2 / metal complex B1 = 92.5 mass % / 7.5 mass %) were dissolved in xylene so that the total concentration was 2 mass %. The resulting xylene solution was spin-coated onto the second layer to form a film with a thickness of 70 nm, and heated at 130°C for 10 minutes in a nitrogen gas atmosphere to form a first layer.

[0395] (Cathode formation) The substrate on which the first layer was formed was placed in a deposition machine. -4 After reducing the pressure to 100 Pa or less, sodium fluoride was deposited on the first layer to a thickness of about 4 nm, and then aluminum was deposited on the sodium fluoride layer to a thickness of about 80 nm to form a cathode. The substrate on which the cathode was formed was then sealed with a glass substrate to produce light-emitting device D6.

[0396] (Evaluation of light-emitting elements) EL light emission was observed when a voltage was applied to the light-emitting element D6. 2 The external quantum efficiency and CIE chromaticity coordinates were measured.

[0397] Example D7 and Comparative Example CD5 Fabrication and Evaluation of Light-Emitting Devices D7 and CD5 Light-emitting devices D7 and CD5 were fabricated in the same manner as in Example D6, except that the materials listed in Table 9 were used instead of "metal complex B1" in Example D6 (formation of the first layer). EL emission was observed by applying a voltage to the light-emitting devices D7 and CD5. When the current density of the light-emitting devices D7 and CD5 was 10 mA / cm 2 The external quantum efficiency and CIE chromaticity coordinates were measured.

[0398] The results of Examples D6 and D7 and Comparative Example CD5 are shown in Table 9. The external quantum efficiency of the light-emitting device D6, D7, and CD5 is shown as a relative value when the external quantum efficiency of the light-emitting device CD5 is set to 1.0.

[0399] [Table 9]

[0400] Example D8 and Comparative Example CD6 Fabrication and Evaluation of Light-Emitting Devices D8 and CD6 Light-emitting devices D8 and CD6 were fabricated in the same manner as in Example D6, except that the materials listed in Table 10 were used instead of "metal complex B1" in Example D6 (formation of the first layer). EL emission was observed by applying a voltage to the light-emitting devices D8 and CD6. The current density of the light-emitting devices D8 and CD6 was 75 mA / cm. 2 The external quantum efficiency and CIE chromaticity coordinates were measured.

[0401] The results of Example D8 and Comparative Example CD6 are shown in Table 10. The external quantum efficiency values ​​of the light-emitting devices D8 and CD6 are shown relative to the external quantum efficiency of the light-emitting device CD6, which was set to 1.0.

[0402] [Table 10]

[0403] <Comparative Example CD7> Fabrication and Evaluation of Light-Emitting Device CD7 Light-emitting device CD7 was fabricated in the same manner as in Example D1, except that "polymer compound HTL-3" was used instead of "polymer compound HTL-1" in Example D1 (formation of the second layer), and "metal complex RC1" was used instead of "metal complex R1" in Example D1 (formation of the first layer). EL emission was observed when a voltage was applied to light-emitting device CD7. 2 The external quantum efficiency and CIE chromaticity coordinates were measured.

[0404] <Comparative Example CD8> Fabrication and Evaluation of Light-Emitting Device CD8 A light-emitting device CD8 was produced in the same manner as in Example D1, except that "polymer compound HTL-C1 and polymer compound HTL-C2 (polymer compound HTL-C1 / polymer compound HTL-C2 = 50% by mass / 50% by mass)" were used instead of "polymer compound HTL-1" in Example D1 (formation of the second layer), and "metal complex RC1" was used instead of "metal complex R1" in Example D1 (formation of the first layer). EL emission was observed when a voltage was applied to the light-emitting device CD8. 2 The external quantum efficiency and CIE chromaticity coordinates were measured.

[0405] The results for Comparative Examples CD7 and CD8 are shown in Table 11. The external quantum efficiency values ​​of the light-emitting elements CD7 and CD8 are shown as relative values ​​when the external quantum efficiency of the light-emitting element CD8 is set to 1.0.

[0406] [Table 11]

[0407] <Examples D9 to D15, Comparative Examples CD9 and CD10> Fabrication and Evaluation of Light-Emitting Devices D9 to D15, CD9, and CD10 Light-emitting devices D9 to D15, CD9, and CD10 were fabricated in the same manner as in Example D1, except that the materials listed in Table 12 were used instead of the "polymer compound HTL-1" in Example D1 (formation of the second layer), and the materials listed in Table 12 were used instead of the "compound H1 and metal complex R1" in Example D1 (formation of the first layer). EL emission was observed by applying a voltage to the light-emitting devices D9 to D15, CD9, and CD10. When the current density of the light-emitting devices D9 to D15, CD9, and CD10 was 10 mA / cm 2 The external quantum efficiency and CIE chromaticity coordinates were measured.

[0408] The results for Examples D9 to D15 and Comparative Examples CD9 and CD10 are shown in Table 12. The external quantum efficiency values ​​of the light-emitting devices D9 to D15 and CD10 are shown as relative values ​​when the external quantum efficiency of the light-emitting device CD9 is set to 1.0.

[0409] [Table 12]

[0410] Example D16, Comparative Examples CD11 and CD12 Fabrication and Evaluation of Light-Emitting Devices D16, CD11, and CD12 In place of "polymer compound HTL-1" in Example D1 (formation of the second layer), Light-emitting devices D16, CD11, and CD12 were fabricated in the same manner as in Example D1, except that the materials described in Example D1 were used and that "Compound H3" was used instead of "Compound H1" in Example D1 (formation of the first layer). EL emission was observed by applying a voltage to the light-emitting devices D16, CD11, and CD12. The current density of the light-emitting devices D16, CD11, and CD12 was 3 mA / cm. 2 The external quantum efficiency and CIE chromaticity coordinates were measured.

[0411] The results of Example D16 and Comparative Examples CD11 and CD12 are shown in Table 13. The external quantum efficiency of the light-emitting device D16 and CD12 are shown as relative values ​​when the external quantum efficiency of the light-emitting device CD11 is set to 1.0.

[0412] [Table 13]

[0413] <Examples D17 and D18 and Comparative Example CD13> Preparation and Evaluation of Light-Emitting Devices D17, D18, and CD13 Light-emitting devices D17, D18, and CD13 were fabricated in the same manner as in Example D1, except that the materials listed in Table 14 were used instead of the polymer compound HTL-1 used in Example D1 (forming the second layer), and that the compound H3 was used instead of the compound H1 used in Example D1 (forming the first layer). EL emission was observed when a voltage was applied to the light-emitting devices D17, D18, and CD13. The current density of the light-emitting devices D17, D18, and CD13 was 0.025 mA / cm. 2 The external quantum efficiency and CIE chromaticity coordinates were measured.

[0414] The results of Examples D17 and D18 and Comparative Example CD13 are shown in Table 14. The external quantum efficiency of the light-emitting device D17 and D18 is shown as a relative value when the external quantum efficiency of the light-emitting device CD13 is set to 1.0.

[0415] [Table 14]

[0416] <Examples D19 and D20 and Comparative Example CD14> Preparation and Evaluation of Light-Emitting Devices D19, D20, and CD14 Light-emitting devices D19 and D20 were manufactured in the same manner as in Example D1, except that the materials shown in Table 15 were used instead of the polymer compound HTL-1 in Example D1 (formation of the second layer), and the compound H3 was used instead of the compound H1 in Example D1 (formation of the first layer). Light-emitting devices D19, D20, and CD14 were fabricated. EL emission was observed when a voltage was applied to the light-emitting devices D19, D20, and CD14. The current density of the light-emitting devices D19, D20, and CD14 was 0.03 mA / cm. 2 The external quantum efficiency and CIE chromaticity coordinates were measured.

[0417] The results for Examples D19 and D20 and Comparative Example CD14 are shown in Table 15. The external quantum efficiency values ​​of the light-emitting devices D19 and D20 are shown as relative values ​​when the external quantum efficiency of the light-emitting device CD14 is set to 1.0.

[0418] [Table 15]

[0419] <Examples D21 to D25 and Comparative Example CD15> Fabrication and Evaluation of Light-Emitting Devices D21 to D25 and CD15 Light-emitting devices D21 to D25 and CD15 were fabricated in the same manner as in Example D1, except that the materials listed in Table 16 were used instead of "compound H1 and metal complex R1" in Example D1 (formation of the first layer). EL emission was observed by applying a voltage to the light-emitting devices D21 to D25 and CD15. When the current density of the light-emitting devices D21 to D25 and CD15 was 10 mA / cm 2 The external quantum efficiency and CIE chromaticity coordinates were measured.

[0420] The results of Examples D21 to D25 and Comparative Example CD15 are shown in Table 16. The table shows the relative values ​​of the external quantum efficiencies of the light-emitting devices D21 to D25 when the external quantum efficiency of the light-emitting device CD15 is set to 1.0.

[0421] [Table 16]

[0422] In each of the devices of the above Examples and Comparative Examples, compounds H1 to H7 were used as host materials having at least one function selected from hole injection, hole transport, electron injection, and electron transport. In each of the devices of the above examples and comparative examples, the metal complexes R1 to R4, RC1, B1 to B3, BC1 and BC2 were used as guest materials having luminescent properties.

Claims

1. A light-emitting device having an anode, a cathode, and a first layer and a second layer provided between the anode and the cathode, the first layer is a layer containing a metal complex represented by formula (1) and a low-molecular-weight compound consisting only of a main group element, the second layer is a layer containing a crosslinked product of a polymer compound including a structural unit having a crosslinking group, The sum of the molecular weights of all the structural units constituting all the polymer compounds contained in the second layer is X １ The total number of crosslinking groups possessed by all structural units constituting all polymer compounds contained in the second layer is defined as Y １ When this is done, (Y １ ×1000) / X １ A light-emitting element having a value of 0.25 or more. 【Chemical 1】 [In the formula, M represents a rhodium atom, a palladium atom, an iridium atom, or a platinum atom. n １ represents an integer of 1 or more, and n ２ represents an integer of 0 or more, provided that when M is a rhodium atom or an iridium atom, n １ +n ２ is 3, and when M is a palladium atom or a platinum atom, n １ +n ２ is 2. E １ and E ２ each independently represents a carbon atom or a nitrogen atom. １ and E ２ When there are a plurality of groups, they may be the same or different. Ring L １ represents an aromatic heterocycle, and this ring may have a substituent. When a plurality of such substituents are present, 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 bonded. Ring L １ When there are multiple groups, they may be the same or different. Ring L ２ represents a polycyclic aromatic hydrocarbon ring or a polycyclic aromatic heterocycle, and these rings may have a substituent. When a plurality of such substituents are present, 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 bonded. Ring L ２ When there are multiple groups, they may be the same or different. Ring L １ and Ring L ２ may be bonded directly or via a divalent group to form a ring. However, ring L １ When is an aromatic heterocycle containing a 5-membered ring, ring L ２ is a polycyclic aromatic hydrocarbon ring or a polycyclic aromatic heterocycle containing at least one of a sulfur atom and a nitrogen atom in the ring. A １ -G １ -A ２ represents an anionic bidentate ligand. １ and A ２ each independently represents a carbon atom, an oxygen atom, or a nitrogen atom, and these atoms may be atoms constituting a ring. １ is a single bond, or A １ and A ２ represents an atomic group constituting a bidentate ligand together with A. １ -G １ -A ２ When there are multiple groups, they may be the same or different.

2. 2. The light-emitting device according to claim 1, wherein the metal complex represented by formula (1) is a metal complex represented by formula (1-A). 【Chemistry 2】 [In the formula, M, n １ , n ２ , E １ , E ２ , ring L １ , and A １ -G １ -A ２ represents the same meaning as above. Ring R Ｂ１ and ring R Ｂ２ Each independently represents an aromatic hydrocarbon ring or an aromatic heterocyclic ring, and these rings may have a substituent. When a plurality of such substituents are present, 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 bonded. Ring R Ｂ１ and ring R Ｂ２ When there are a plurality of groups, they may be the same or different. Ring L １ and Ring R Ｂ１ may be bonded directly or via a divalent group to form a ring. X ａ and X ｂ Each of X independently represents a direct bond or a divalent group, and the group may have a substituent. When a plurality of the substituents are present, 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 bonded. ａ and X ｂ When there are a plurality of groups, they may be the same or different. Ring R Ｂ１ and X ａ and may be bonded directly or via a divalent group to form a ring. Ｂ１ and X ｂ and may be bonded directly or via a divalent group to form a ring. Ｂ２ and X ａ and may be bonded directly or via a divalent group to form a ring. Ｂ２ and X ｂ may be bonded directly or via a divalent group to form a ring. However, ring L １ When is an aromatic heterocycle containing a five-membered ring, at least one of (i), (ii) and (iii) is satisfied. (i) X ａ and X ｂ At least one of the groups is -S- and / or -N(R Ｘａ’ )-, and the group may have a substituent. (ii) Ring R Ｂ１ and ring R Ｂ２ At least one of the above is an aromatic heterocycle containing at least one of a sulfur atom and a nitrogen atom in the ring, and the aromatic heterocycle may have a substituent. (iii) Ring R Ｂ１ and ring R Ｂ２ is an aromatic hydrocarbon ring, and X ａ and X ｂ are each independently a direct bond or a divalent group, and the divalent group is -C(=O)- and -C( R Ｘａ ) ２ - is a divalent group consisting of at least one selected from the group consisting of -, and the group may have a substituent. R Ｘａ represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, an aryloxy group, a monovalent heterocyclic group, a substituted amino group, or a halogen atom, and these groups may have a substituent. When there are multiple such 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 bonded. Ｘａ 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 bonded. R Ｘａ’ represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may have a substituent. When a plurality of such substituents are present, 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 bonded.]

3. 3. The light-emitting device according to claim 2, wherein the metal complex represented by formula (1-A) is a metal complex represented by formula (1-A1), formula (1-A2), or formula (1-A3). 【Chemistry 3】 [In the formula, M, n １ , n ２ , ring L １ , X ａ , X ｂ , and A １ -G １ -A ２ represents the same meaning as above. R ５ , R ６ , R ７ , R ８ , R ９ , R １０ , R １１ and R １２ R each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, an aryloxy group, a monovalent heterocyclic group, a substituted amino group, or a halogen atom, and these groups may have a substituent. ５ , R ６ , R ７ , R ８ , R ９ , R １０ , R １１ and R １２ When a plurality of R are present, they may be the same or different. ６ and R ７ , R ７ and R ８ , R ８ and R ９ , R １０ and R １１ , R ５ and R １２ , and ring L １ and the substituent that R may have. ５ may be bonded to each other to form a ring together with the atoms to which they are bonded. However, ring L １ is an aromatic heterocycle containing a 5-membered ring, X ａ and X ｂ are each independently a direct bond or a divalent group, and the divalent group is -S-, -C(=O)-, -C(R Ｘａ ) ２ - and -N(R Ｘａ’ )—, and the group may have a substituent. R Ｘａ and R Ｘａ’ has the same meaning as above. In formula (1-A1), R ６ and X ａ , R ９ and X ｂ , and R １０ and X ｂ may be bonded to each other directly or via a divalent group to form a ring together with the atom to which they are bonded. In formula (1-A2), R ５ and X ａ , R ６ and X ａ , R ９ and X ｂ , and R １０ and X ｂ may be bonded to each other directly or via a divalent group to form a ring together with the atom to which they are bonded. In formula (1-A3), R ６ and X ａ , R ９ and X ｂ , and R １２ and X ａ may be bonded directly to each other or via a divalent group to form a ring together with the atom to which they are bonded.

4. The ring L １ is a pyridine ring, a diazabenzene ring, an azanaphthalene ring, a diazanaphthalene ring, a diazole ring, or a triazole ring, and these rings may have a substituent, and when a plurality of the substituents are present, the substituents 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 bonded.

5. 4. The light-emitting device according to claim 1, wherein the structural unit having a crosslinking group is a structural unit represented by formula (Z) or a structural unit represented by formula (Z'). 【Chemistry 4】 [In the formula, n represents an integer of 1 or more. nA represents an integer of 0 or more. When a plurality of nAs are present, they may be the same or different. Ar ３ represents a hydrocarbon group, a heterocyclic group, or a group in which at least one hydrocarbon group and at least one heterocyclic group are directly bonded, and these groups may have a substituent. When a plurality of such substituents are present, 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 bonded. L 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 a substituent. When a plurality of such substituents are present, they may be the same or different and may be bonded to each other to form a ring together 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 a substituent. When a plurality of such substituents are present, they may be the same or different and may be bonded to each other to form a ring together with the atom to which they are bonded. L Ａ When there are multiple groups, they may be the same or different. X represents a crosslinking group. When a plurality of X's are present, they may be the same or different. 【Chemistry 5】 [In the formula, mA, m, and c each independently represent an integer of 0 or more. When a plurality of mA are present, they may be the same or different. When there are multiple m's, 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 a substituent. When a plurality of such substituents are present, 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 bonded. ５ When there are multiple groups, they may be the same or different. Ar ４ and Ar ６ each independently represents an arylene group or a divalent heterocyclic group, and these groups may have a substituent. When a plurality of such substituents are present, 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 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 a substituent. When a plurality of such substituents are present, they may be the same or different and may be bonded to each other to form a ring together 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 a substituent. When a plurality of such substituents are present, they may be the same or different and may be bonded to each other to form a ring together with the atom to which they are bonded. K Ａ When there are multiple groups, they may be the same 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 a substituent. When a plurality of such substituents are present, 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 bonded. When a plurality of X' are present, they may be the same or different, provided that at least one X' is a bridging group.]

6. 4. The light-emitting device according to claim 1, wherein the crosslinking group is a crosslinking group selected from Group A of crosslinking groups. (Bridging group A group) 【Chemistry 6】 [In the formula, R ＸＬ represents a methylene group, an oxygen atom, or a sulfur atom; n ＸＬ represents an integer of 0 to 5. ＸＬ When there are multiple n, they may be the same or different. ＸＬ When a plurality of groups are present, they may be the same or different. *1 represents the bonding position. These bridging groups may have a substituent, and when a plurality of such substituents are present, 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 bonded.]

7. 4. The light-emitting device according to claim 1, wherein the low-molecular compound consisting only of a typical element is a compound represented by formula (H-1). 【Chemistry 7】 [In the formula, Ar Ｈ１ and Ar Ｈ２ each independently represents an aryl group or a monovalent heterocyclic group, and these groups may have a substituent. n Ｈ１ and n Ｈ２ Each independently represents 0 or 1. Ｈ１ When there are a plurality of n, they may be the same or different. Ｈ２ may be the same or different. n Ｈ３ represents an integer of 0 or more and 10 or less. L Ｈ１ represents an arylene group, a divalent heterocyclic group, or —[C(R Ｈ１１ ) ２ ]n Ｈ１１ -, and these groups may have a substituent. Ｈ１ When there are multiple n, they may be the same or different. Ｈ１１ represents an integer of 1 or more and 10 or less. Ｈ１１ represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, or a monovalent heterocyclic group, and these groups may have a substituent. Ｈ１１ 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 bonded. L Ｈ２ is -N(-L Ｈ２１ -R Ｈ２１ )- represents a group represented by L Ｈ２ When a plurality of L are present, they may be the same or different. Ｈ２１ represents a single bond, an arylene group or a divalent heterocyclic group, and these groups may have a substituent. Ｈ２１ is a hydrogen atom , an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may have a substituent.]

8. 4. The light-emitting element according to claim 1, wherein the first layer further contains at least one 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.

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

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

Images