Light emitting element

Abstract

To provide a light emitting element with a low driving voltage.SOLUTION: A light emitting element includes an anode, a light emitting layer, a first electron transport layer, a second electron transport layer and a cathode in this order. The light emitting layer contains: a low molecule B including boron and at least one selected from among oxygen, sulfur, selenium, sp3 carbon and nitrogen; and / or a polymer B including a constituent unit with a group derived from the low molecule B. The first and second electron transport layers each include one selected from among a low molecule H-1, a low molecule ET-1, a low molecule ET-2, and a polymer containing at least one selected from among a constituent unit with a group derived from the low molecule ET-1, a constituent unit with a group derived from the low molecule ET-2, a constituent unit X and a constituent unit Y, and the first electron transport layer and / or the second electron transport layer includes a polymer containing at least one selected from among a constituent unit with a group derived from the low molecule ET-1, a constituent unit with a group derived from the low molecule ET-2, the constituent unit X and the constituent unit Y.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to light-emitting devices. [Background technology]

[0002] Light-emitting devices such as organic electroluminescence devices can be suitably used for displays and lighting applications. For example, Patent Document 1 describes a light-emitting device having only one layer, an emitting layer containing Compound B1, and an electron transport layer.

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

[0004] [Patent Document 1] Patent Publication No. 2023-50142 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the driving voltage of the above-mentioned light-emitting elements is not necessarily sufficiently low. Therefore, an object of one embodiment of the present disclosure is to provide a light-emitting device with a low driving voltage.

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

[12] . [1] A light-emitting device having an anode, a cathode, a light-emitting layer provided between the anode and the cathode, a first electron transport layer provided between the light-emitting layer and the cathode, and a second electron transport layer provided between the first electron transport layer and the cathode, The light-emitting layer contains boron atoms, oxygen atoms, sulfur atoms, selenium atoms, sp 3a layer containing at least one compound selected from the group consisting of a low molecular weight compound (B) having a fused heterocyclic skeleton (b) containing at least one atom selected from the group consisting of a carbon atom and a nitrogen atom in the ring, and a polymer compound (B) containing a structural unit having a group in which one or more hydrogen atoms have been removed from the low molecular weight compound (B), the first electron transport layer and the second electron transport layer are layers containing at least one selected from the group consisting of low molecular weight compounds represented by formula (H-1), low molecular weight compounds represented by formula (ET-1), low molecular weight compounds represented by formula (ET-2), and polymer compounds containing at least one structural unit selected from the group consisting of structural units having a group obtained by removing one or more hydrogen atoms from the low molecular weight compound represented by formula (ET-1), structural units having a group obtained by removing one or more hydrogen atoms from the low molecular weight compound represented by formula (ET-2), structural units represented by formula (X), and structural units represented by formula (Y), At least one of the first electron transport layer and the second electron transport layer comprises a structural unit having a group in which one or more hydrogen atoms have been removed from a low molecular weight compound represented by formula (ET-1), a structural unit having a group in which one or more hydrogen atoms have been removed from a low molecular weight compound represented by formula (ET-2), a layer containing a polymer compound containing at least one structural unit selected from the group consisting of a structural unit represented by formula (X) and a structural unit represented by formula (Y). [ka] [In the formula, Ar H1 and Ar H2 are each independently an aryl group, a monovalent heterocyclic group, or a substituted amino 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. n H1 represents an integer greater than or equal to 0. L H1represents a divalent group, and the divalent group 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 H1 When a plurality of groups are present, they may be the same or different, and may be bonded to each other directly or via a divalent group to form a ring. Ar H1 and Ar H2 and may be bonded directly or via a divalent group to form a ring. H1 and Ar H1 and may be bonded directly or via a divalent group to form a ring. H1 and Ar H2 may be bonded directly or via a divalent group to form a ring. [ka] [In the formula, nE1 represents an integer of 1 or more. Ar E1 represents an aromatic hydrocarbon group or a heterocyclic group, and these groups may have a substituent. R E1 represents a group represented by formula (ES-1). E1 When there are multiple, they may be the same or different. -R E3 -{(Q E1 ) nE3 -Y E1 (M E1 ) aE1 (Z E1 ) bE1} mE1 (ES-1) [In the formula, nE3 and bE1 each independently represent an integer of 0 or more, and aE1 and mE1 each independently represent an integer of 1 or more. When a plurality of nE3, aE1, and bE1 are present, they may be the same or different. However, R E3is a single bond, mE1 is 1. aE1 and bE1 are selected so that the charge of the group represented by formula (ES-1) is 0. R E3 is a single bond, a hydrocarbon group, a heterocyclic group, or OR E3’ (R E3’ represents a hydrocarbon group or a heterocyclic group, and these groups may have a substituent. Q E1 represents an alkylene group, a cycloalkylene group, an arylene group, an oxygen atom or a sulfur atom, and these groups may have a substituent. E1 When there are multiple groups, they may be the same or different. Y E1 is -CO2 - , -SO3 - , -SO2 - or -PO3 2- Y E1 When there are multiple groups, they may be the same or different. M E1 represents an alkali metal cation, an alkaline earth metal cation or an ammonium cation, and the ammonium cation may have a substituent. E1 There are multiple If present, they may be the same or different. Z E1 is F - , Cl - , Br - , I - , O.H. - , B(R E4 )4 - , R E4 SO3 - , R E4 COO - , NO3 - , SO4 2- , HSO4 - , PO4 3- , HPO4 2- , H2PO4 - , BF4 - or PF6 - Represents R E4represents an alkyl group, a cycloalkyl group, or an aryl group, and these groups may have a substituent. E1 When there are multiple, they may be the same or different. [ka] [In the formula, nE2 represents an integer of 1 or more. Ar E2 represents an aromatic hydrocarbon group or a heterocyclic group, and these groups may have a substituent. R E2 represents a group represented by formula (ES-2). E2 When there are multiple, they may be the same or different. -R E5 -{(Q E2 ) nE4 -Y E2 (M E2 ) aE2 (Z E2 ) bE2} mE2 (ES-2) [In the formula, nE4 and bE2 each independently represent an integer of 0 or more, and aE2 and mE2 each independently represent an integer of 1 or more. When a plurality of nE4, aE2, and bE2 are present, they may be the same or different. However, R E5 is a single bond, mE2 is 1. aE2 and bE2 are selected so that the charge of the group represented by formula (ES-2) is 0. R E5 is a single bond, a hydrocarbon group, a heterocyclic group, or OR E5’ (R E5’ represents a hydrocarbon group or a heterocyclic group, and these groups may have a substituent. Q E2 represents an alkylene group, a cycloalkylene group, an arylene group, an oxygen atom or a sulfur atom, and these groups may have a substituent. E2 When there are multiple groups, they may be the same or different. Y E2-C + R E6 2, -N + R E6 3, -P + R E6 3, -S + R E6 2 or -I + R E6 Represents 2. R E6 represents a hydrogen atom, an alkyl group, a cycloalkyl group, or an aryl group, and these groups may have a substituent. E6 may be the same or different. E2 When there are multiple groups, they may be the same or different. M E2 is F - , Cl - , Br - , I - , O.H. - , B(R E7 )4 - , R E7 SO3 - , R E7 COO - , BF4 - , SbCl6 - or SbF6 - Represents R E7 represents an alkyl group, a cycloalkyl group, or an aryl group, and these groups may have a substituent. M E2 When there are multiple groups, they may be the same or different. Z E2 represents an alkali metal cation or an alkaline earth metal cation. E2 When there are multiple, they may be the same or different. [ka] [In the formula, a X1 and a X2 each independently represents an integer of 0 or greater. Ar X1 and Ar X3each 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 When there are multiple, they may be the same or different. [ka] [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. [2] The light-emitting device according to [1], wherein the second electron transport layer is a layer containing a polymer compound including at least one structural unit selected from the group consisting of a structural unit having a group in which one or more hydrogen atoms have been removed from a low-molecular-weight compound represented by formula (ET-1) and a structural unit having a group in which one or more hydrogen atoms have been removed from a low-molecular-weight compound represented by formula (ET-2). [3] The light-emitting device according to [1] or [2], wherein the first electron transport layer is a layer containing a polymer compound including at least one structural unit selected from the group consisting of a structural unit represented by formula (X) and a structural unit represented by formula (Y). [4] The fused heterocyclic skeleton (b) is composed of a boron atom, an oxygen atom, a sulfur atom, and a nitrogen atom. The light-emitting device according to any one of [1] to [3], wherein the ring contains at least one selected from the group consisting of: [5] The light-emitting device according to any one of [1] to [4], wherein the low molecular weight compound (B) is a compound represented by formula (1-1), a compound represented by formula (1-2), or a compound represented by formula (1-3). [ka] [In the formula, Ar 1 , Ar 2 and Ar 3 each independently represents an aromatic hydrocarbon group or a 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. Y 1 represents an oxygen atom, a sulfur atom, a selenium atom, a group represented by -N(Ry)-, an alkylene group, or a cycloalkylene group, and these groups may have 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. Y 2 and Y 3are each independently a single bond, an oxygen atom, a sulfur atom, a selenium atom, a group represented by -N(Ry)-, a group represented by -B(Ry)-, an alkylene group, a cycloalkylene group, an arylene group, or a divalent heterocyclic group, and these groups may have 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. Ry 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 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 Ry, they may be the same or different. Y 1 and Ar 1 may be bonded directly or via a divalent group to form a ring. 1 and Ar 2 may be bonded directly or via a divalent group to form a ring. 2 and Ar 1 may be bonded directly or via a divalent group to form a ring. 2 and Ar 3 may be bonded directly or via a divalent group to form a ring. 3 and Ar 2 may be bonded directly or via a divalent group to form a ring. 3 and Ar 3 may be bonded directly or via a divalent group to form a ring. [6] The above Y 1 , the Y 2 and the Y 3 are each independently an oxygen atom, a sulfur atom, or a group represented by -N(Ry)-. [7] The light-emitting device according to any one of [1] to [6], wherein the light-emitting layer further contains at least one compound selected from the group consisting of a metal complex represented by formula (1) and a polymer compound (A) containing a structural unit having a group in which one or more hydrogen atoms have been removed from the metal complex represented by formula (1): [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 the ring 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. Ring L 1 When there are multiple groups, they may be the same or different. Ring L 2 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 L 2 When there are multiple groups, they may be the same or different. Ring L 1 and the substituents which may be present on ring L 2may 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. 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. [8] The ring L 1 is an aromatic heterocycle containing a 5-membered ring or an aromatic heterocycle containing a 6-membered ring, and these rings may have a substituent, and ring L 2 is an aromatic hydrocarbon ring containing a 5-membered ring or a 6-membered ring, or an aromatic heterocycle containing a 5-membered ring or a 6-membered ring, and these rings may have a substituent. [9] The light-emitting device according to any one of [1] to [8], wherein the light-emitting layer further contains at least one selected from the group consisting of a low molecular weight compound represented by formula (H-1) and a polymer compound containing at least one structural unit selected from the group consisting of a structural unit represented by formula (X) and a structural unit represented by formula (Y).

[10] The light-emitting device according to any one of [1] to [9], wherein the light-emitting layer further contains 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.

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

[10] , wherein the light-emitting layer and the first electron transport layer are adjacent to each other.

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

[0011] , wherein the first electron transport layer and the second electron transport layer are adjacent to each other. [Effects of the Invention]

[0007] According to an embodiment of the present disclosure, a light-emitting element with a low driving voltage can be provided. DETAILED DESCRIPTION OF THE INVENTION

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

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

[0010] "Room temperature" means 25°C. 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. 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.

[0011] "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:

[0012] "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 from the viewpoint of the light-emitting properties of the light-emitting device of the present disclosure, etc. 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.

[0013] 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. 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, a dodecyl group, and groups 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).

[0014] 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 and groups in which some or all of the hydrogen atoms in the cyclohexyl group have been substituted with substituents.

[0015] The number of carbon atoms in the "alkylene group" is usually 1 to 20, preferably 1 to 15, 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.

[0016] The number of carbon atoms in the "cycloalkylene group" is usually 3 to 20, preferably 4 to 10, and more preferably 5 to 7, 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.

[0017] An "aromatic hydrocarbon group" refers to a group obtained by removing one or more hydrogen atoms directly bonded to a carbon atom that constitutes a ring from an aromatic hydrocarbon. A group obtained by removing one hydrogen atom directly bonded to a carbon atom that constitutes a ring from an aromatic hydrocarbon is also called an "aryl group." A group obtained by removing two hydrogen atoms directly bonded to a carbon atom that constitutes a ring from an aromatic hydrocarbon 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. Examples of the "aromatic hydrocarbon group" include groups in which one or more hydrogen atoms directly bonded to a carbon atom constituting the ring have been removed from a monocyclic aromatic hydrocarbon (such as benzene) or a polycyclic aromatic hydrocarbon (such as bicyclic aromatic hydrocarbons such as naphthalene, indene, naphthoquinone, indenone, and tetralone; tricyclic aromatic hydrocarbons such as anthracene, phenanthrene, dihydrophenanthrene, fluorene, anthraquinone, phenanthoquinone, and fluorenone; tetracyclic aromatic hydrocarbons such as benzanthracene, benzophenanthrene, and benzofluorene; pentacyclic aromatic hydrocarbons such as dibenzanthracene, dibenzophenanthrene, dibenzofluorene, indenofluorene, and benzofluoranthene; hexacyclic aromatic hydrocarbons such as spirobifluorene; and heptacyclic aromatic hydrocarbons such as benzospirobifluorene and acenaphthofluoranthene). The aromatic hydrocarbon group may be a group in which a plurality of groups are bonded to a monocyclic aromatic hydrocarbon or a polycyclic aromatic hydrocarbon, in which one or more hydrogen atoms directly bonded to carbon atoms constituting the ring have been removed. The aromatic hydrocarbon group may have a substituent.

[0018] 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 40, 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 40, 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.

[0019] The number of carbon atoms in the "cycloalkoxy group" is usually 3 to 40, preferably 3 to 20, and more preferably 4 to 10, not including the number of carbon atoms in the substituents. The cycloalkoxy group may have a substituent. Examples of the cycloalkoxy group include a cyclohexyloxy group and a group in which some or all of the hydrogen atoms are substituted. Substituted groups are included.

[0020] 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.

[0021] A "heterocyclic group" refers to a group obtained by removing, from a heterocyclic compound, 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 heterocyclic compound, one or more hydrogen atoms directly bonded to atoms constituting the ring, is preferred. A group obtained by removing, from a heterocyclic compound, 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 heterocyclic compound, p hydrogen atoms directly bonded to atoms constituting the ring is also called a "p-valent aromatic heterocyclic group". Examples of the "aromatic heterocyclic compound" include compounds in which the heterocycle itself exhibits aromaticity, such as azole, thiophene, furan, pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, and carbazole, as well as compounds in which an aromatic ring is condensed with a heterocycle, even if the heterocycle itself does not exhibit aromaticity, such as phenoxazine, phenothiazine, and benzopyran. 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. Examples of the heterocyclic group include monocyclic heterocyclic compounds (e.g., furan, thiophene, oxadiazole, thiadiazole, pyrrole, diazole, triazole, tetrazole, pyridine, diazabenzene, and triazine), and polycyclic heterocyclic compounds (e.g., bicyclic heterocyclic compounds 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, etc.). tricyclic heterocyclic compounds such as benzophenone, acridone, phenazaborine, phenophosphazine, phenoselenazine, phenazasiline, azaanthracene, diazaanthracene, azaphenanthrene, and diazaphenanthrene; tetracyclic heterocyclic compounds such as hexaazatriphenylene, benzocarbazole, azabenzocarbazole, diazabenzocarbazole, benzonaphthofuran, and benzonaphthothiophene; dibenzocarbazole, indolocarbazole, indenocarbazole, Examples of heterocyclic groups include 5-ring heterocyclic compounds such as azaindolocarbazole, diazaindolocarbazole, azaindenocarbazole, and diazaindenocarbazole; 6-ring heterocyclic compounds such as carbazolocarbazole, benzoindolocarbazole, and benzoindenocarbazole; and 7-ring heterocyclic compounds such as dibenzoindolocarbazole and dibenzoindenocarbazole. Examples of heterocyclic groups include groups obtained by removing one or more hydrogen atoms directly bonded to atoms constituting the ring from a monocyclic heterocyclic compound or a polycyclic heterocyclic compound. The heterocyclic group may have a substituent.

[0022] The term "halogen atom" refers to a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom.

[0023] 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. 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 further substituted with substituents. Examples of the substituted amino group include a dimethylamino group, a diethylamino group, a diphenylamino group, a bis(methylphenyl)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 further substituted with substituents.

[0024] The "alkenyl group" may be either straight-chain or branched. The number of carbon atoms in a straight-chain alkenyl group, not including the number of carbon atoms in substituents, is usually 2 to 30, preferably 3 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 30, preferably 4 to 20, and more preferably 4 to 10. The number of carbon atoms in the "cycloalkenyl group" is usually 3 to 30, preferably 4 to 20, and more preferably 5 to 10, not including the number of carbon atoms in substituents. The alkenyl group and the cycloalkenyl group may have a substituent. Examples of the alkenyl group include a vinyl group, a 1-propenyl group, a 2-butenyl group, a 3-butenyl group, a 3-pentenyl group, a 4-pentenyl group, a 1-hexenyl group, a 5-hexenyl group, a 7-octenyl group, and groups in which some or all of the hydrogen atoms in these groups have been substituted with a substituent. Examples of the cycloalkenyl group include a cyclohexenyl group, a cyclohexadienyl group, a cyclooctatrienyl group, a norbornylenyl group, and groups in which some or all of the hydrogen atoms in these groups have been substituted with a substituent.

[0025] 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 30, and 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 30, and preferably 4 to 10. The number of carbon atoms in the "cycloalkynyl group" is usually 4 to 30, and preferably 4 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.

[0026] The "crosslinking group" is a group that can generate a new bond by heating, ultraviolet irradiation, near-ultraviolet irradiation, visible light irradiation, infrared irradiation, 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)). (Bridging group A group)

[0027] [ka]

[0028] [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. XL When 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.]

[0029] 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, and 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.

[0030] 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)-. The divalent group may be a group 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.

[0031] In this specification, the absolute value of the difference between the energy level of the lowest excited triplet state and the energy level of the lowest excited singlet state (hereinafter referred to as "ΔE ST The value of is calculated as follows: First, the ground state of the compound is optimized using the density functional theory at the B3LYP level. At this time, 6-31G* is used as the basis function. Then, using the optimized structure obtained, the ΔE ST However, if an atom for which 6-31G* cannot be used is included, LANL2DZ is used for that atom. The quantum chemistry calculation program used for the calculation is Gaussian09.

[0032] The light-emitting element of the present disclosure is a light-emitting element having an anode, a cathode, a light-emitting layer provided between the anode and the cathode, a first electron transport layer provided between the light-emitting layer and the cathode, and a second electron transport layer provided between the first electron transport layer and the cathode.

[0033] <Light-emitting layer> In the light-emitting device of the present disclosure, the light-emitting layer is a light-emitting layer containing at least one compound (hereinafter also referred to as "compound (B)") selected from the group consisting of a low-molecular-weight compound (B) and a polymer compound (B) (hereinafter also referred to as "light-emitting layer (B)"). That is, the light-emitting layer (B) is a light-emitting layer containing compound (B). In the light-emitting device of the present disclosure, the "light-emitting layer" is preferably a layer in which electrons injected from the cathode and holes injected from the anode recombine. In the light-emitting device of the present disclosure, recombination of electrons and holes preferably does not occur in layers other than the light-emitting layer, such as the electron injection layer, electron transport layer, hole transport layer, and hole injection layer. The light-emitting layer (B) may contain only one type of compound (B), or may contain two or more types.

[0034] The content of the compound (B) in the light-emitting layer (B) may be within a range that allows the light-emitting layer (B) to exhibit its functions. The content of the compound (B) in the light-emitting layer (B) may be, for example, 0.01 to 100% by mass based on the total amount of the light-emitting layer (B), and is preferably 0.05 to 90% by mass, more preferably 0.1 to 70% by mass, even more preferably 0.2 to 50% by mass, particularly preferably 0.5 to 30% by mass, and especially preferably 1 to 10% by mass, since this further reduces the driving voltage of the light-emitting device of the present disclosure.

[0035] [Compound (B)] The compound (B) is at least one selected from the group consisting of a low molecular weight compound (B) and a polymer compound (B). In the light-emitting device of the present disclosure, it is preferred that only the light-emitting layer is a layer formed using the compound (B). More specifically, it is preferred that the hole transport layer is a layer formed using a material that does not contain the compound (B), it is more preferred that both the hole transport layer and the hole injection layer are layers formed using materials that do not contain the compound (B), it is even more preferred that the layer located between the light-emitting layer and the cathode is a layer formed using a material that does not contain the compound (B), and it is particularly preferred that the layers other than the light-emitting layer are layers formed using materials that do not contain the compound (B).

[0036] (Low molecular compound (B)) The low molecular weight compound (B) contains a boron atom, an oxygen atom, a sulfur atom, a selenium atom, and sp 3 The compound is a low molecular weight compound having a fused heterocyclic skeleton (b) containing at least one atom selected from the group consisting of carbon atoms and nitrogen atoms in the ring. In the low molecular weight compound (B), when the fused heterocyclic skeleton (b) contains a nitrogen atom, it is preferable that at least one of the nitrogen atoms contained in the fused heterocyclic skeleton (b) is a nitrogen atom that does not form a double bond, and it is more preferable that all of the nitrogen atoms contained in the fused heterocyclic skeleton (b) are nitrogen atoms that do not form a double bond. The low molecular weight compound (B) is preferably a low molecular weight compound that does not contain a transition metal element (that is, a low molecular weight compound that is composed only of main group elements).

[0037] The number of carbon atoms in the fused heterocyclic skeleton (b) is usually 1 to 60, preferably 5 to 40, and more preferably 10 to 25, not including the number of carbon atoms in the substituent. The number of heteroatoms in the fused heterocyclic skeleton (b), not including the number of heteroatoms in the substituents, is usually 2 to 30, preferably 2 to 15, more preferably 2 to 10, even more preferably 2 to 5, and particularly preferably 2 or 3. The number of boron atoms in the fused heterocyclic skeleton (b) is usually 1 to 10, preferably 1 to 5, more preferably 1 to 3, and even more preferably 1, not including the number of boron atoms in the substituents. Oxygen atom, sulfur atom, selenium atom, sp 3 The total number of carbon atoms and nitrogen atoms, not including the number of atoms of substituents, is usually 1 to 20, preferably 1 to 10, more preferably 1 to 5, even more preferably 1 to 3, and particularly preferably 2.

[0038] The fused heterocyclic skeleton (b) preferably contains a boron atom and at least one atom selected from the group consisting of an oxygen atom, a sulfur atom, and a nitrogen atom in the ring, since this reduces the driving voltage of the light-emitting element of the present disclosure; more preferably contains a boron atom and a nitrogen atom in the ring; and even more preferably contains a nitrogen atom that does not form a double bond with the boron atom in the ring.

[0039] The fused heterocyclic skeleton (b) is preferably a 3- to 12-cyclic fused heterocyclic skeleton, more preferably a 3- to 6-cyclic fused heterocyclic skeleton, and even more preferably a 5-cyclic fused heterocyclic skeleton, since this lowers the driving voltage of the light-emitting device of the present disclosure.

[0040] The fused heterocyclic skeleton (b) can also be said to be a compound having a heterocyclic group (b') containing the fused heterocyclic skeleton (b).

[0041] The heterocyclic group (b') is a group consisting of a boron atom, an oxygen atom, a sulfur atom, a selenium atom, and a sp 3 The heterocyclic group may be a group obtained by removing one or more hydrogen atoms directly bonded to atoms constituting the ring from a polycyclic heterocyclic compound containing at least one atom selected from the group consisting of carbon atoms and nitrogen atoms in the ring, and the group may have a substituent. In the heterocyclic group (b'), the polycyclic heterocyclic compound is preferably a polycyclic heterocyclic compound containing a boron atom and at least one atom selected from the group consisting of an oxygen atom, a sulfur atom, and a nitrogen atom in the ring, because this lowers the driving voltage of the light-emitting element of the present disclosure. More preferably, it is a polycyclic heterocyclic compound containing a boron atom and a nitrogen atom in the ring. Even more preferably, it is a polycyclic heterocyclic compound containing a nitrogen atom that does not form a double bond with the boron atom in the ring. In the heterocyclic group (b'), the polycyclic heterocyclic compound is preferably a heterocyclic compound having 3 to 12 rings, more preferably a heterocyclic compound having 3 to 6 rings, and even more preferably a heterocyclic compound having 5 rings, because this lowers the driving voltage of the light-emitting device of the present disclosure.

[0042] The substituent that the heterocyclic group (b') may have is preferably a halogen atom, a cyano group, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryloxy group, an aryl group, a monovalent heterocyclic group, or a substituted amino group, more preferably an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, a monovalent heterocyclic group, or a substituted amino group, still more preferably an alkyl group, a cycloalkyl group, an aryl group, a monovalent heterocyclic group, or a substituted amino group, and particularly preferably an alkyl group, a cycloalkyl group, or an aryl group, and these groups may further have a substituent.

[0043] The aryl group in the substituent that the heterocyclic group (b') 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, and more preferably a monocyclic, bicyclic or tricyclic aromatic hydrocarbon. A group in which one hydrogen atom directly bonded to an atom constituting the ring has been removed from hydrogen chloride, 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, or fluorene, and particularly preferably a phenyl group, and these groups may have a substituent. The monovalent heterocyclic group in the substituent that the heterocyclic group (b') may have is preferably a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from a monocyclic or bicyclic to hexacyclic heterocyclic compound, or a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from a monocyclic, bicyclic, or tricyclic heterocyclic compound, more preferably a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, carbazole, dibenzofuran, dibenzothiophene, phenoxazine, or phenothiazine, and particularly preferably a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from pyridine, diazabenzene, or triazine, and these groups may have a substituent. In the substituted amino group in the substituent that the heterocyclic group (b') 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 the same as the examples and preferred ranges of the aryl group and the monovalent heterocyclic group in the substituent that the heterocyclic group (b') may have, respectively.

[0044] The substituent that the heterocyclic group (b') may further have is preferably a halogen atom, a cyano group, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryloxy group, an aryl group, a monovalent heterocyclic group, or a substituted amino group, more preferably an alkyl group, a cycloalkyl group, an aryl group, a monovalent heterocyclic group, or a substituted amino group, still more preferably an alkyl group, a cycloalkyl group, or an aryl group, and particularly preferably an alkyl group or a cycloalkyl group, and these groups may further have a substituent, but preferably do not have a further substituent. Examples and preferred ranges of the aryl group, monovalent heterocyclic group, and substituted amino group in the substituent that the heterocyclic group (b') may further have are the same as the examples and preferred ranges of the aryl group, monovalent heterocyclic group, and substituted amino group in the substituent that the heterocyclic group (b') may have.

[0045] The term "nitrogen atom not forming a double bond" means a nitrogen atom that is bonded to three other atoms via single bonds. "Containing a nitrogen atom not forming a double bond in the ring" means that the ring contains -N(-R N )-(wherein, R N represents a hydrogen atom or a substituent.) or the formula:

[0046] [ka] This means that the compound contains a group represented by the formula:

[0047] The low molecular weight compound (B) is preferably a thermally activated delayed fluorescence (TADF) compound, since this lowers the driving voltage of the light-emitting device of the present disclosure. Here, the thermally activated delayed fluorescent compound is a compound having thermally activated delayed fluorescent properties.

[0048] ΔE of low molecular weight compound (B) ST may be 2.0 eV or less, and may be 1.5 eV or less. The ΔE of the low molecular weight compound (B) may be 0.01 eV or less, 1.0 eV or less, or 0.80 eV or less, but is preferably 0.60 eV or less, more preferably 0.55 eV or less, and even more preferably 0.50 eV or less, since this lowers the driving voltage of the light-emitting device of the present disclosure. ST may be 0.001 eV or more, 0.01 eV or more, 0.10 eV or more, 0.20 eV or more, 0.30 eV or more, or 0.40 eV or more.

[0049] The molecular weight of the low molecular weight compound (B) is preferably 1×10 2 ~5×10 3 and more preferably 2×10 2 ~3×10 3 and more preferably 3×10 2 ~1.5×10 3 and particularly preferably 4 × 10 2 ~1×10 3 is.

[0050] The low molecular weight compound (B) is preferably a compound represented by formula (1-1), formula (1-2) or formula (1-3), more preferably a compound represented by formula (1-2) or formula (1-3), and even more preferably a compound represented by formula (1-2), because this lowers the driving voltage of the light-emitting element of the present disclosure.

[0051] Ar 1 , Ar 2 and Ar 3is preferably a group obtained by removing one or more hydrogen atoms directly bonded to an atom constituting the ring from a monocyclic or bicyclic to hexacyclic aromatic hydrocarbon or a monocyclic or bicyclic to hexacyclic heterocyclic compound, since this reduces the driving voltage of the light-emitting element of the present disclosure; more preferably a group obtained by removing one or more hydrogen atoms directly bonded to an atom constituting the ring from a monocyclic, bicyclic, or tricyclic aromatic hydrocarbon or a monocyclic, bicyclic, or tricyclic heterocyclic compound; even more preferably a group obtained by removing one or more hydrogen atoms directly bonded to an atom constituting the ring from a monocyclic aromatic hydrocarbon or a monocyclic heterocyclic compound; particularly preferably a group obtained by removing one or more hydrogen atoms directly bonded to an atom constituting the ring from benzene, pyridine, or diazabenzene; and especially preferably a group obtained by removing one or more hydrogen atoms directly bonded to an atom constituting the ring from benzene, and these groups may have a substituent. Ar 1 , Ar 2 and Ar 3 The examples and preferred range of the substituents which may be possessed by the heterocyclic group (b') are the same as the examples and preferred range of the substituents which may be possessed by the heterocyclic group (b').

[0052] Y 1 is preferably an oxygen atom, a sulfur atom, a group represented by -N(Ry)-, or an alkylene group, since this results in a lower driving voltage for the light-emitting element of the present disclosure, more preferably an oxygen atom, a sulfur atom, or a group represented by -N(Ry)-, and even more preferably a group represented by -N(Ry)-, and these groups may have a substituent.

[0053] Y 2 and Y 3is preferably a single bond, an oxygen atom, a sulfur atom, a selenium atom, a group represented by -N(Ry)-, a group represented by -B(Ry)-, an alkylene group, or a cycloalkylene group, since this results in a lower driving voltage for the light-emitting element of the present disclosure; more preferably a single bond, an oxygen atom, a sulfur atom, a group represented by -N(Ry)-, a group represented by -B(Ry)-, or an alkylene group; even more preferably an oxygen atom, a sulfur atom, a group represented by -N(Ry)-, or an alkylene group; particularly preferably an oxygen atom, a sulfur atom, or a group represented by -N(Ry)-; and especially preferably a group represented by -N(Ry)-, and these groups may have a substituent.

[0054] Y 2 and Y 3 The arylene group in the formula (I) is preferably a group obtained by removing two hydrogen atoms directly bonded to carbon atoms constituting the ring from a monocyclic or bicyclic to hexacyclic aromatic hydrocarbon, more preferably a group obtained by removing two hydrogen atoms directly bonded to carbon atoms constituting the ring from a monocyclic, bicyclic or tricyclic aromatic hydrocarbon, even more preferably a group obtained by removing two hydrogen atoms directly bonded to carbon atoms constituting the ring from benzene, naphthalene, anthracene, phenanthrene, dihydrophenanthrene or fluorene, particularly preferably a group obtained by removing two hydrogen atoms directly bonded to carbon atoms constituting the ring from benzene, naphthalene or fluorene, and particularly preferably a phenylene group, and these groups may have a substituent. Y 2 and Y 3The divalent heterocyclic group in the formula (I) is preferably a group obtained by removing two hydrogen atoms directly bonded to atoms (preferably carbon atoms) constituting the ring from a monocyclic or bicyclic to hexacyclic heterocyclic compound, more preferably a group obtained by removing two hydrogen atoms directly bonded to atoms (preferably carbon atoms) constituting the ring from a monocyclic, bicyclic or tricyclic heterocyclic compound, and even more preferably pyridine, diazabenzene, triazine, azanaphthalene, dibenzofuran, dibenzothiophene, carbazole, azacarbazole, diazacarbazole, phenoxazine, phenothiazine, or 9,10-dihydroacridine. or a group obtained by removing, from 5,10-dihydrophenazine, two hydrogen atoms that are directly bonded to atoms that constitute the ring (preferably carbon atoms), and particularly preferred is a group obtained by removing, from pyridine, diazabenzene, triazine, carbazole, phenoxazine, phenothiazine, 9,10-dihydroacridine, or 5,10-dihydrophenazine, two hydrogen atoms that are directly bonded to atoms that constitute the ring (preferably carbon atoms), and particularly preferred is a group obtained by removing, from pyridine, diazabenzene, or triazine, two hydrogen atoms that are directly bonded to atoms that constitute the ring (preferably carbon atoms), and these groups may have a substituent. Y 1 , Y 2 and Y 3 The alkylene group in the formula (I) is preferably a methylene group, an ethylene group or a propylene group, more preferably a methylene group, and these groups may have a substituent.

[0055] In formula (1-2), the driving voltage of the light-emitting device of the present disclosure is lowered, so that Y 1 and Y 2 and Y are preferably an oxygen atom, a sulfur atom, or a group represented by —N(Ry)—. 1 and Y 2 In formula (1-3), it is more preferable that both of Y and Y are groups represented by -N(Ry)-, since this leads to a lower driving voltage of the light-emitting device of the present disclosure. 1 , Y 2 and Y 3are preferably all oxygen atoms, sulfur atoms or groups represented by -N(Ry)-, and Y 1 , Y 2 and Y 3 It is more preferable that all of the above are groups represented by -N(Ry)-.

[0056] Y 1 , Y 2 and Y 3 The examples and preferred range of the substituents which may be possessed by the heterocyclic group (b') are the same as the examples and preferred range of the substituents which may be possessed by the heterocyclic group (b').

[0057] Ry is preferably an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, more preferably an aryl group or a monovalent heterocyclic group, and even more preferably an aryl group, and these groups may have a substituent. Examples and preferred ranges of the aryl group and monovalent heterocyclic group for Ry are the same as the examples and preferred ranges of the aryl group and monovalent heterocyclic group in the substituent that the heterocyclic group (b') may have, respectively. Examples and preferred ranges of the substituents that Ry may have are the same as the examples and preferred ranges of the substituents that the heterocyclic group (b') may have.

[0058] Y 1 and Ar 1 may be bonded directly or via a divalent group to form a ring, but it is preferable that they do not form a ring, as this facilitates the synthesis of the low molecular weight compound (B). Y 1 and Ar 1 When the groups bond to each other via a divalent group to form a ring, the divalent group is preferably an alkylene group, a cycloalkylene group, an arylene group, a divalent heterocyclic group, or —N(R 0 )-, -B(R 0 )-, a group represented by -O-, a group represented by -S-, or a group represented by -Se-, and more preferably an alkylene group, a cycloalkylene group, or a -N(R 0 )-, -B(R 0)-, -O-, -S- or -Se-, and more preferably an alkylene group, -N(R 0 )-, a group represented by -O-, or a group represented by -S-, and particularly preferred are a group represented by -O-, a group represented by -S-, or -N(R 0 )-, and particularly preferably, -N(R 0 )-, and these groups may have a substituent. Y 1 and Ar 1 and Y are bonded to each other via a divalent group to form a ring. Examples and preferred ranges of the arylene group, divalent heterocyclic group, and alkylene group in the divalent group are respectively listed below. 2 and Y 3 The examples and preferred ranges of the arylene group, divalent heterocyclic group and alkylene group in the above are the same as those in the above. Y 1 and Ar 1 When Y and Y are bonded via a divalent group to form a ring, examples and preferred ranges of the substituents that the divalent group may have are as follows: 2 and Y 3 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. Y 1 and Ar 1 and R in the divalent group when they are bonded to form a ring via a divalent group 0 Examples and preferred ranges of are the same as those of Ry.

[0059] Y 1 and Ar 2 and may be bonded directly or via a divalent group to form a ring, but it is preferable that they do not form a ring, as this facilitates the synthesis of the low molecular weight compound (B). 1 and Ar 2 When Y and Y are bonded via a divalent group to form a ring, examples and preferred ranges of the divalent group include: 1 and Ar 1 and are bonded via a divalent group to form a ring, the examples and preferred ranges of which are the same as those of the divalent group. Y 2 and Ar 1 and may be bonded directly or via a divalent group to form a ring, but it is preferable that they do not form a ring, as this facilitates the synthesis of the low molecular weight compound (B). 2 and Ar 1 When Y and Y are bonded via a divalent group to form a ring, examples and preferred ranges of the divalent group include: 1 and Ar 1 and are bonded via a divalent group to form a ring, the examples and preferred ranges of which are the same as those of the divalent group. Y 2 and Ar 3 and may be bonded directly or via a divalent group to form a ring, but it is preferable that they do not form a ring, as this facilitates the synthesis of the low molecular weight compound (B). 2 and Ar 3 When Y and Y are bonded via a divalent group to form a ring, examples and preferred ranges of the divalent group include: 1 and Ar 1 and are bonded via a divalent group to form a ring, the examples and preferred ranges of which are the same as those of the divalent group. Y 3 and Ar 2 and may be bonded directly or via a divalent group to form a ring, but it is preferable that they do not form a ring, as this facilitates the synthesis of the low molecular weight compound (B). 3 and Ar 2 When Y and Y are bonded via a divalent group to form a ring, examples and preferred ranges of the divalent group include: 1 and Ar 1 and are bonded via a divalent group to form a ring, the examples and preferred ranges of which are the same as those of the divalent group. Y 3 and Ar 3 and may be bonded directly or via a divalent group to form a ring, but it is preferable that they do not form a ring, as this facilitates the synthesis of the low molecular weight compound (B). 3 and Ar 3 When Y and Y are bonded via a divalent group to form a ring, examples and preferred ranges of the divalent group include:1 and Ar 1 and are bonded via a divalent group to form a ring, the examples and preferred ranges of which are the same as those of the divalent group.

[0060] Examples of the low molecular weight compound (B) include a compound represented by the following formula and the compound B1 described below. 1 represents an oxygen atom or a sulfur atom. 1 When there are multiple groups, they may be the same or different.

[0061] [ka]

[0062] [ka]

[0063] The maximum peak wavelength of the emission spectrum of the low molecular weight compound (B) at 25°C is preferably 380 nm or more, more preferably 400 nm or more, even more preferably 420 nm or more, and particularly preferably 440 nm or more. The maximum peak wavelength of the emission spectrum of the low molecular weight compound (B) at 25°C is preferably 750 nm or less, more preferably 620 nm or less, even more preferably 570 nm or less, particularly preferably 495 nm or less, and especially preferably 480 nm or less. The half width of the maximum peak in the emission spectrum of the low molecular weight compound (B) at 25° C. is preferably 50 nm or less, more preferably 40 nm or less, even more preferably 30 nm or less, and particularly preferably 25 nm or less. The maximum peak wavelength of the emission spectrum of a compound at room temperature was measured by dissolving the compound in an organic solvent such as xylene, toluene, chloroform, or tetrahydrofuran to prepare a dilute solution (1 × 10 -6 Mass%~1×10 -3% by mass), the PL spectrum of the diluted solution can be measured at room temperature. Xylene is preferred as the organic solvent for dissolving the compound.

[0064] (High molecular compound (B)) The polymer compound (B) is a polymer compound that includes a structural unit (hereinafter also referred to as "structural unit (B)") having a group in which one or more hydrogen atoms have been removed from the low molecular weight compound (B). The structural unit (B) is preferably a structural unit having a group obtained by removing 1 to 5 hydrogen atoms from a low molecular weight compound (B), since this facilitates the synthesis of the polymer compound (B), more preferably a structural unit having a group obtained by removing 1 to 3 hydrogen atoms from a low molecular weight compound (B), and even more preferably a structural unit having a group obtained by removing 1 or 2 hydrogen atoms from a low molecular weight compound (B). The structural unit (B) is a polymer compound (B) that can be easily synthesized and can be used in the light-emitting device of the present disclosure. Since the driving voltage of the structural unit is lower, the structural unit represented by formula (BP-1), formula (BP-2) or formula (BP-3) is preferred, and the structural unit represented by formula (BP-1) or formula (BP-2) is more preferred.

[0065] [ka]

[0066] [In the formula, M BP1 represents a group obtained by removing one hydrogen atom from the low molecular weight compound (B). M BP2 represents a group obtained by removing two hydrogen atoms from the low molecular weight compound (B). M BP3 represents a group obtained by removing three hydrogen atoms from the low molecular weight compound (B). L BP1 are each independently an alkylene group, a cycloalkylene group, an arylene group, a divalent heterocyclic group, -N(R BP1)-, 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 atoms to which they are bonded. R BP1 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. L BP1 When there are a plurality of groups, they may be the same or different. n BP1 represents an integer between 0 and 10. Ar BP1 represents a hydrocarbon group or a 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.

[0067] L BP1 is preferably an alkylene group, a cycloalkylene group, an arylene group, or a divalent heterocyclic group, more preferably an alkylene group or an arylene group, and even more preferably an arylene group, and these groups may have a substituent. L BP1 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. L BP1 The alkylene group in the formula (I) is preferably a methylene group, an ethylene group or a propylene group, more preferably a methylene group, and these groups may have a substituent. R BP1 Examples and preferred ranges of R X1 ~R X3 The examples and preferred ranges are the same as those of the above.

[0068] n BP1is preferably an integer of 0 to 5, preferably an integer of 0 to 3, more preferably 0 or 1, and even more preferably 0.

[0069] Ar BP1 The hydrocarbon group in the formula (I) is an aromatic hydrocarbon group which may have a substituent. and optionally substituted aliphatic hydrocarbon groups. BP1 The hydrocarbon group in the formula (I) includes groups in which a plurality of these groups are bonded. Ar BP1 In the above, the aliphatic hydrocarbon group is an alkylene group or a cycloalkylene group to which a hydrogen atom n BP1 Preferably, the alkylene group is a group obtained by removing n hydrogen atoms. BP1 These groups may have a substituent. Examples and preferred ranges of the alkylene group include the groups described below in L H1 Examples of the alkylene group and preferred ranges thereof are as follows: Ar BP1 In the above, the aromatic hydrocarbon group is a group having n hydrogen atoms from an arylene group. BP1 Examples of the arylene group and a preferred range thereof include the Arylene group described below. Y1 Examples of the arylene group and preferred ranges thereof are as follows: Ar BP1 As the heterocyclic group in BP1 Examples of the divalent heterocyclic group and a preferred range thereof are described below in the section on Ar Y1 Examples of the divalent heterocyclic group and preferred ranges thereof are as follows: L BP1 and Ar BP1 Examples of the substituents that may be possessed by Ar Y1 The examples and preferred ranges of the substituents that may be possessed by the group represented by the formula:

[0070] Examples of the structural unit (B) include structural units represented by the following formula:

[0071] [ka]

[0072] [ka]

[0073] [In the formula, R TS is a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, a monovalent heterocyclic group, or a substituted amino group, and these groups may further have a substituent. TS may be the same or different.]

[0074] R TS Examples and preferred ranges of the aryl group, monovalent heterocyclic group, and substituted amino group in 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. R TS Examples of the substituents that may be possessed by Ar and their preferred ranges are described later in the section on 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 of the substituents that the group may further have.

[0075] The content of the structural unit (B) contained in the polymer compound (B) may be within a range that allows the polymer compound (B) to function. The content of the structural unit (B) contained in the polymer compound (B) is, for example, 0.01 to 100 mol % relative to the total content of the structural units contained in the polymer compound (B). Since this reduces the driving voltage of the light-emitting device of the present disclosure, the content is preferably 0.05 to 90 mol %, more preferably 0.1 to 70 mol %, even more preferably 0.2 to 50 mol %, particularly preferably 0.5 to 30 mol %, and especially preferably 1 to 10 mol %. The polymer compound (B) may contain only one type of structural unit (B), or two or more types of structural units (B).

[0076] It is preferable that the polymer compound (B) further contains at least one structural unit selected from the group consisting of structural units represented by the below-described formula (X) and structural units represented by the below-described formula (Y), because this reduces the driving voltage of the light-emitting device of the present disclosure. That is, it is preferable that the polymer compound (B) is a polymer compound that contains at least one structural unit selected from the group consisting of structural units represented by the below-described formula (X) and structural units represented by the below-described formula (Y), and structural unit (B). The polymer compound (B) comprises at least one structural unit selected from the group consisting of a structural unit represented by the formula (X) described below and a structural unit represented by the formula (Y) described below, and the structural unit (B). When included, the structural unit (B) is preferably different from the structural unit represented by the formula (X) described below and the structural unit represented by the formula (Y) described below. It is preferable that the polymer compound (B) further contains a constitutional unit represented by the formula (Y) described below, since this leads to a lower driving voltage of the light-emitting device of the present disclosure. It is preferable that the polymer compound (B) further contains a structural unit represented by the formula (X) described below, since this provides the polymer compound (B) with excellent hole transport properties and reduces the driving voltage of the light-emitting element of the present disclosure. It is preferable that the polymer compound (B) further contains a structural unit represented by the below-described formula (X) and a structural unit represented by the below-described formula (Y), since this will provide the polymer compound (B) with excellent hole transport properties and further reduce the driving voltage of the light-emitting device of the present disclosure.

[0077] When the polymer compound (B) contains a structural unit represented by the formula (X) described below, the content of the structural unit represented by the formula (X) described below may be within a range that allows the polymer compound (B) to function as intended. When the polymer compound (B) contains a structural unit represented by the formula (X) described below, the content of the structural unit represented by the formula (X) described below relative to the total content of structural units contained in the polymer compound (B) is, for example, 0.01 to 99.9 mol %, and is preferably 0.05 to 90 mol %, more preferably 0.1 to 70 mol %, even more preferably 0.2 to 50 mol %, particularly preferably 0.5 to 30 mol %, and particularly preferably 1 to 10 mol %, because this provides excellent hole transport properties for the polymer compound (B) and reduces the driving voltage of the light-emitting device of the present disclosure. The polymer compound (B) may contain only one type of constitutional unit represented by formula (X), or may contain two or more types.

[0078] When the polymer compound (B) contains a structural unit represented by formula (Y), the content of the structural unit represented by formula (Y) may be within a range that allows the polymer compound (B) to function. When the polymer compound (B) contains a structural unit represented by formula (Y), the content of the structural unit represented by formula (Y) relative to the total content of structural units contained in the polymer compound (B) is, for example, 1 to 99.99 mol %, and is preferably 10 to 99.95 mol %, more preferably 30 to 99.9 mol %, even more preferably 50 to 99.8 mol %, particularly preferably 70 to 99.5 mol %, and especially preferably 90 to 99 mol %, because this further reduces the driving voltage of the light-emitting device of the present disclosure. The polymer compound (B) may contain only one type of constitutional unit represented by formula (Y), or may contain two or more types.

[0079] When the polymer compound (B) contains a structural unit represented by formula (X) and / or a structural unit represented by formula (Y), and structural unit (B), the total content of the structural unit represented by formula (X), the structural unit represented by formula (Y), and structural unit (B) may be within a range that allows the polymer compound (B) to function. When the polymer compound (B) contains a structural unit represented by formula (X) and / or a structural unit represented by formula (Y), and structural unit (B), the total content of the structural unit represented by formula (X), the structural unit represented by formula (Y), and structural unit (B) is, for example, 1 to 100 mol% relative to the total content of structural units contained in the polymer compound (B). Since the hole transport properties of the polymer compound (B) are excellent and the driving voltage of the light-emitting device of the present disclosure is lower, the total content is preferably 10 to 100 mol%, more preferably 30 to 100 mol%, even more preferably 50 to 100 mol%, particularly preferably 70 to 100 mol%, and especially preferably 90 to 100 mol%.

[0080] Examples of polymer compound (B) include polymer compounds BP-1 to BP-4. Here, "other" refers to structural units other than the structural unit (B), the structural unit represented by formula (X), and the structural unit represented by formula (Y).

[0081] [Table 1]

[0082] The polymer compound (B) 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.

[0083] Examples and preferred ranges of the polystyrene-equivalent number average molecular weight of the polymer compound (B) are the same as the examples and preferred ranges of the polystyrene-equivalent number average molecular weight of the first polymer compound described below. Examples and preferred ranges of the polystyrene-equivalent weight average molecular weight of the polymer compound (B) are the same as the examples and preferred ranges of the polystyrene-equivalent weight average molecular weight of the polymer compound of the light-emitting layer B2 described below.

[0084] (Method for producing polymer compound (B)) The polymer compound (B) can be produced by the same method as the method for producing the polymer compound of the light-emitting layer B2 described below.

[0085] <Light-emitting layer B1> The light-emitting layer (B) preferably further contains at least one compound (hereinafter also referred to as "compound (A)") selected from the group consisting of a metal complex represented by formula (1) and a polymer compound (A) containing a structural unit having a group in which one or more hydrogen atoms have been removed from the metal complex represented by formula (1), because this reduces the driving voltage of the light-emitting device of the present disclosure. That is, the light-emitting layer (B) is preferably a layer containing the compound (B) and the compound (A) (hereinafter also referred to as "light-emitting layer B1"). The light-emitting layer B1 may contain only one kind of compound (B) and one kind of compound (A), or may contain two or more kinds of compounds.

[0086] The total content of the compound (B) and the compound (A) in the light-emitting layer B1 may be within a range that allows the light-emitting layer B1 to function properly. The total content of the compound (B) and the compound (A) in the light-emitting layer B1 may be, for example, 0.01 to 100% by mass based on the total amount of the light-emitting layer B1, and is preferably 0.1 to 99% by mass, more preferably 0.5 to 90% by mass, even more preferably 1 to 70% by mass, particularly preferably 5 to 50% by mass, and especially preferably 10 to 30% by mass, since this reduces the driving voltage of the light-emitting device of the present disclosure. The content of the compound (B) in the light-emitting layer B1 is within a range in which the function of the light-emitting layer B1 can be exhibited. The content of compound (B) in the light-emitting layer B1 is, for example, 0.01 to 99 parts by mass, where the total content of compound (B) and compound (A) is taken as 100 parts by mass, and is preferably 0.05 to 90 parts by mass, more preferably 0.1 to 70 parts by mass, still more preferably 0.5 to 50 parts by mass, particularly preferably 1 to 30 parts by mass, and particularly preferably 2 to 20 parts by mass, since this further reduces the driving voltage of the light-emitting device of the present disclosure.

[0087] In the light-emitting layer B1, the compound (A) preferably interacts physically, chemically, or electrically with the compound (B). This interaction makes it possible to improve or adjust, for example, the light-emitting properties, charge transport properties, or charge injection properties of the light-emitting element of the present disclosure. In the light-emitting element of the present disclosure, taking the light-emitting material as an example, compound (A) and compound (B) electrically interact with each other, and electrical energy is efficiently transferred from compound (A) to compound (B), thereby making it possible to make compound (B) emit light more efficiently, and the driving voltage of the light-emitting element of the present disclosure can be reduced.

[0088] From the above viewpoint, in the light-emitting layer B1, it is preferable that the compound (A) 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 lower driving voltage of the light-emitting device of the present disclosure. From the above viewpoint, in the light-emitting layer B1, as an example of a light-emitting material, the compound (B) preferably has light-emitting properties, since this leads to a lower driving voltage of the light-emitting device of the present disclosure. From the above viewpoint, in the light-emitting layer B1, the lowest excited singlet state (S1) of the compound (A) preferably has a higher energy level than the lowest excited singlet state (S1) of the compound (B), since this results in a lower driving voltage for the light-emitting element of the present disclosure. From the above viewpoint, in the light-emitting layer B1, the lowest excited triplet state (T1) of the compound (A) preferably has a higher energy level than the lowest excited triplet state (T1) of the compound (B), since this lowers the driving voltage of the light-emitting element of the present disclosure.

[0089] Since the light-emitting device of the present disclosure can be produced by a wet method, the compound (A) is preferably one that is soluble in a solvent capable of dissolving the compound (B).

[0090] [Compound (A)] The compound (A) is at least one selected from the group consisting of a metal complex represented by formula (1) and a polymer compound (A).

[0091] (Metal complex represented by formula (1)) The metal complex represented by formula (1) is preferably a low molecular weight compound. The molecular weight of the metal complex represented by formula (1) is preferably 3×10 2 ~1×10 4 and more preferably 4×10 2 ~7×10 3 and more preferably 5×10 2 ~5×10 3 and particularly preferably 6 × 10 2 ~3×10 3 and particularly preferably 7 × 10 2 ~2×10 3 is.

[0092] M is preferably an iridium atom or a platinum atom, and more preferably an iridium atom, since this lowers the driving voltage of the light-emitting device of the present disclosure. 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.

[0093] 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 E1 and E 2 In addition, since the metal complex represented by formula (1) can be easily synthesized, E 1 There are multiple If there are multiple E 1 It is preferable that at least two of the E 1 It is more preferable that all of E are the same. In addition, since the metal complex represented by formula (1) can be easily synthesized, 2 If there are multiple E 2 It is preferable that at least two of the E 2 It is more preferred that all of the following are the same:

[0094] Ring L 1 The number of carbon atoms in the aromatic heterocycle is preferably 1 to 30, more preferably 1 to 20, even more preferably 1 to 10, particularly preferably 1 to 5, and especially preferably 1 to 3, not including the number of carbon atoms of the substituent. Ring L 1 The number of heteroatoms in the aromatic heterocycle is preferably 1 to 30, more preferably 1 to 10, still more preferably 1 to 5, and particularly preferably 1 to 3, not including the number of heteroatoms in the substituents. Ring L 1 Examples of the aromatic heterocyclic ring include, among the aromatic heterocyclic rings exemplified in the section on heterocyclic groups above, aromatic heterocyclic rings containing one or more nitrogen atoms in the ring, and the aromatic heterocyclic rings may have a substituent. 1is preferably an aromatic heterocycle containing a 5-membered ring or an aromatic heterocycle containing a 6-membered ring, since this lowers the driving voltage of the light-emitting element of the present disclosure, more preferably an aromatic heterocycle containing a 5-membered ring containing two to four nitrogen atoms in the ring, or an aromatic heterocycle containing a 6-membered ring containing one to four nitrogen atoms in the ring, even more preferably an aromatic heterocycle containing a 5-membered ring containing two or three nitrogen atoms in the ring, or an aromatic heterocycle containing a 6-membered ring containing one or two nitrogen atoms in the ring, and particularly preferably an aromatic heterocycle containing a 5-membered ring containing two or three nitrogen atoms in the ring, and these rings may have a substituent. 1 When E is a 6-membered aromatic heterocycle, 1 is preferably a carbon atom. Ring L 1 is preferably a monocyclic, bicyclic, or tricyclic aromatic heterocycle, since this lowers the driving voltage of the light-emitting element of the present disclosure, more preferably a pyridine ring, a diazabenzene ring, an azanaphthalene ring, a diazanaphthalene ring, a diazole ring, or a triazole ring, even more preferably a pyridine ring, an azanaphthalene ring, a diazole ring, or a triazole ring, particularly preferably a diazole ring or triazole ring, and especially preferably a triazole ring, and these rings may have a substituent. 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:

[0095] Ring L 2 The number of carbon atoms in the aromatic hydrocarbon ring is preferably 6 to 60, more preferably 6 to 40, and even more preferably 6 to 20, not including the number of carbon atoms in the substituent. Ring L 2Examples of the aromatic hydrocarbon ring in include the aromatic hydrocarbon rings exemplified in the section on aromatic hydrocarbon groups above, and preferably aromatic hydrocarbon rings containing a 5- or 6-membered ring, which may have a substituent. 2 The aromatic hydrocarbon ring in the formula (I) is preferably a monocyclic, bicyclic, or tricyclic aromatic hydrocarbon ring (preferably an aromatic hydrocarbon ring containing a 5- or 6-membered ring) exemplified in the section on aromatic hydrocarbon groups above, since this results in a lower driving voltage for the light-emitting element of the present disclosure, more preferably a benzene ring, a naphthalene ring, a fluorene ring, a phenanthrene ring, or a dihydrophenanthrene ring, even more preferably a benzene ring or a fluorene ring, and particularly preferably a benzene ring, and these rings may have a substituent. Ring L 2 The number of carbon atoms in the aromatic heterocycle in the formula (I) is preferably 1 to 60, more preferably 2 to 40, and even more preferably 3 to 20, not including the number of carbon atoms in the substituent. 2 The number of heteroatoms in the aromatic heterocycle is preferably 1 to 10, more preferably 1 to 5, and even more preferably 1 to 3, not including the number of heteroatoms in the substituents. Ring L 2 Examples of the aromatic heterocycle in the formula (I) include the aromatic heterocycles exemplified in the section on heterocyclic groups above, and are preferably aromatic heterocycles containing a 5- or 6-membered ring, and these aromatic heterocycles may have a substituent. 2The aromatic heterocycle in the formula (I) is preferably a monocyclic, bicyclic, or tricyclic aromatic heterocycle (preferably an aromatic heterocycle containing a 5- or 6-membered ring) exemplified in the section on heterocyclic groups above, since this results in a lower driving voltage for the light-emitting element of the present disclosure, more preferably a pyridine ring, a diazabenzene ring, an azanaphthalene ring, a diazanaphthalene ring, an indole ring, a benzofuran ring, a benzothiophene ring, a carbazole ring, an azacarbazole ring, a diazacarbazole ring, a dibenzofuran ring, or a dibenzothiophene ring, even more preferably a pyridine ring, a diazabenzene ring, a carbazole ring, a dibenzofuran ring, or a dibenzothiophene ring, and particularly preferably a pyridine ring or a diazabenzene ring, and these rings may have a substituent. Ring L 2 is preferably a monocyclic, bicyclic, or tricyclic aromatic hydrocarbon ring (preferably an aromatic hydrocarbon ring containing a five- or six-membered ring) or a monocyclic, bicyclic, or tricyclic aromatic heterocycle (preferably an aromatic heterocycle containing a five- or six-membered ring), since this further reduces the driving voltage of the light-emitting element of the present disclosure, more preferably a benzene ring, fluorene ring, pyridine ring, diazabenzene ring, carbazole ring, dibenzofuran ring, or dibenzothiophene ring, even more preferably a benzene ring, pyridine ring, or diazabenzene ring, and particularly preferably a benzene ring, and these rings may have a substituent. Since the metal complex represented by formula (1) can be easily synthesized, ring L 2 If there are multiple rings, there are multiple rings L 2 At least two of the rings L are preferably the same. 2 It is more preferred that all of the following are the same:

[0096] Since the driving voltage of the light-emitting device of the present disclosure is further reduced, the ring L 1 is an aromatic heterocycle containing a 5-membered ring (preferably a monocyclic, bicyclic or tricyclic aromatic heterocycle) or an aromatic heterocycle containing a 6-membered ring (preferably a monocyclic, bicyclic or tricyclic aromatic heterocycle), and ring L 2is preferably an aromatic hydrocarbon ring containing a 5-membered ring or a 6-membered ring (preferably a monocyclic, bicyclic or tricyclic aromatic hydrocarbon ring), or an aromatic heterocycle containing a 5-membered ring or a 6-membered ring (preferably a monocyclic, bicyclic or tricyclic aromatic heterocycle), and ring L 1 is a pyridine ring, a diazabenzene ring, an azanaphthalene ring, a diazanaphthalene ring, a diazole ring, or a triazole ring, and ring L 2 is more preferably a benzene ring, a fluorene ring, a pyridine ring, a diazabenzene ring, a carbazole ring, a dibenzofuran ring or a dibenzothiophene ring, and ring L 1 is a pyridine ring, a diazabenzene ring, an azanaphthalene ring, a diazanaphthalene ring, a diazole ring, or a triazole ring, and ring L 2 is more preferably a benzene ring, a pyridine ring or a diazabenzene ring, and ring L 1 is a pyridine ring, an azanaphthalene ring, a diazole ring, or a triazole ring, and ring L 2 is particularly preferably a benzene ring, and ring L 1 is a diazole ring or a triazole ring, and ring L 2 is particularly preferably a benzene ring, and ring L 1 is a triazole ring, and ring L 2 is particularly preferably a benzene ring, and these rings may have a substituent.

[0097] Ring L 1 and ring L 2 The substituent that may be possessed by the group (hereinafter also referred to as "primary substituent") 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, even more preferably an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and particularly preferably an alkyl group, a cycloalkyl group, or an aryl group, and these groups may further possess a substituent (hereinafter also referred to as "secondary substituent").

[0098] Ring L 1 and ring L 2 It is preferred that at least one of the groups have a primary substituent, since this results in a lower driving voltage for the light-emitting device of the present disclosure. In the metal complex represented by formula (1), ring L 1 and ring L 2 at least one of the rings L 1 and ring L 2 If there are multiple rings, there are multiple rings L 1 and ring L 2 At least one of the rings L may have a primary substituent. However, since the driving voltage of the light-emitting device of the present disclosure becomes lower, it is preferable that a plurality of rings L 1 and ring L 2 Preferably, at least two of the rings L have primary substituents. 1 and ring L 2 It is more preferable that at least three of the rings L 1 and ring L 2 at least one of the rings L 1 and ring L 2 When a plurality of rings L are present, the driving voltage of the light-emitting device of the present disclosure becomes lower. 1 At least two of the rings L have primary substituents, or 2 Preferably, at least two of the rings L have primary substituents. 1 All of the rings L have primary substituents, or multiple rings L 2 It is more preferable that all of the rings L 1 It is more preferred that all of the groups have a primary substituent. In the metal complex represented by formula (1), ring L 1 and ring L 2 When at least one of the rings L has a primary substituent, 1 and ring L 2The number of primary substituents possessed by at least one of the above is usually 1 to 10, and is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1 or 2, since this allows the metal complex represented by formula (1) to be easily synthesized and also reduces the driving voltage of the light-emitting element of the present disclosure. In the metal complex represented by formula (1), ring L 1 and ring L 2 has a primary substituent and M is a rhodium atom or an iridium atom, then ring L 1 and ring L 2 The total number of primary substituents possessed by is usually 1 to 30, and is preferably 1 to 18, more preferably 2 to 12, and even more preferably 3 to 6, since this allows the metal complex represented by formula (1) to be easily synthesized and also reduces the driving voltage of the light-emitting element of the present disclosure. In the metal complex represented by formula (1), ring L 1 and ring L 2 has a primary substituent and M is a palladium atom or a platinum atom, ring L 1 and ring L 2 The total number of primary substituents possessed by is usually 1 to 20, and is preferably 1 to 12, more preferably 1 to 8, and even more preferably 2 to 4, since this allows the metal complex represented by formula (1) to be easily synthesized and also reduces the driving voltage of the light-emitting element of the present disclosure.

[0099] The alkyl group in the primary substituent is preferably a methyl group, a propyl group, an isopropyl group, a tert-butyl group, a pentyl group, a hexyl group, or an octyl group, more preferably a methyl group, a propyl group, or a tert-butyl group, and these groups may have a substituent. The aryl group in the primary substituent is preferably a group in which one hydrogen atom directly bonded to a carbon atom constituting the ring has been removed from a monocyclic, bicyclic, or tricyclic aromatic hydrocarbon, more preferably a phenyl group, a naphthyl group, or a fluorenyl group, and even more preferably a phenyl group, and these groups may have a substituent. The monovalent heterocyclic group in the primary substituent is preferably a group in which one hydrogen atom directly bonded to a carbon atom or heteroatom constituting the ring has been removed from a monocyclic, bicyclic, or tricyclic heterocyclic compound, more preferably a group in which one hydrogen atom directly bonded to a carbon atom or heteroatom constituting the ring has been removed from a pyridine ring, a diazabenzene ring, a triazine ring, an azanaphthalene ring, a diazanaphthalene ring, a carbazole ring, a dibenzofuran ring, or a dibenzothiophene ring, and even more preferably a group in which one hydrogen atom directly bonded to a carbon atom constituting the ring has been removed from a pyridine ring, a diazabenzene ring, or a triazine ring, and these groups may have a substituent. In the substituted amino group in the primary substituent, 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. The examples and preferred ranges of are the same as the examples and preferred ranges of the aryl group and monovalent heterocyclic group in the primary substituent, respectively.

[0100] Examples and preferred ranges of secondary substituents (substituents that the primary substituent may further have) are the same as the examples and preferred ranges of the primary substituents. The secondary substituent may further have a substituent (hereinafter also referred to as a "tertiary substituent"). Examples and preferred ranges of the tertiary substituent (the substituent that the secondary substituent may further have) are the same as the examples and preferred ranges of the primary substituent. The tertiary substituent may further have a substituent (hereinafter also referred to as a "quaternary substituent"). The quaternary substituent (a substituent that the tertiary substituent may further 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, even 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 because this allows for the easy synthesis of the metal complex represented by formula (1). Examples and preferred ranges of the aryl group, monovalent heterocyclic group, and substituted amino group in the secondary substituent, tertiary substituent, and quaternary substituent are the same as the examples and preferred ranges of the aryl group, monovalent heterocyclic group, and substituted amino group in the primary substituent, respectively.

[0101] (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

[0102] [ka] [In the formula, * represents the site binding to M.]

[0103] Examples of the metal complex represented by formula (1) include the metal complexes shown below.

[0104] [ka]

[0105] [ka]

[0106] [ka]

[0107] [ka]

[0108] [ka]

[0109] (High molecular compound (A)) The polymer compound (A) is a polymer compound that includes a structural unit (hereinafter also referred to as "structural unit (A)") having a group in which one or more hydrogen atoms have been removed from the metal complex represented by formula (1). The structural unit (A) is preferably a structural unit having a group obtained by removing 1 to 5 hydrogen atoms from the metal complex represented by formula (1), more preferably a structural unit having a group obtained by removing 1 to 3 hydrogen atoms from the metal complex represented by formula (1), and even more preferably a structural unit having a group obtained by removing 1 or 2 hydrogen atoms from the metal complex represented by formula (1), because this facilitates the synthesis of the polymer compound (A). The structural unit (A) is preferably a structural unit represented by formula (AP-1), formula (AP-2), or formula (AP-3), more preferably a structural unit represented by formula (AP-1) or formula (AP-2), and even more preferably a structural unit represented by formula (AP-1), because this facilitates synthesis of the polymer compound (A) and reduces the driving voltage of the light-emitting device of the present disclosure.

[0110] [ka]

[0111] [In the formula, M AP1 represents a group in which one hydrogen atom has been removed from the metal complex represented by formula (1). M AP2 represents a group obtained by removing two hydrogen atoms from the metal complex represented by formula (1). M AP3 represents a group in which three hydrogen atoms have been removed from the metal complex represented by formula (1). L AP1 are each independently an alkylene group, a cycloalkylene group, an arylene group, a divalent heterocyclic group, -N(R AP1 )-, 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 atoms to which they are bonded. R AP1 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. L AP1 When there are a plurality of groups, they may be the same or different. n AP1 represents an integer between 0 and 10. Ar AP1 represents a hydrocarbon group or a 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.

[0112] L AP1 Examples and preferred ranges of L BP1 The examples and preferred ranges are the same as those of the above. R AP1 Examples and preferred ranges of R BP1 The examples and preferred ranges are the same as those of the above. n AP1 Examples and preferred ranges of n BP1 The examples and preferred ranges are the same as those of the above. Ar AP1 Examples and preferred ranges of Ar BP1 The examples and preferred ranges are the same as those of the above.

[0113] Examples of the structural unit (A) include structural units represented by the following formula:

[0114] [ka]

[0115] [ka]

[0116] [ka]

[0117] [ka]

[0118] [ka]

[0119] [ka]

[0120] [ka]

[0121] [In the formula, Z 2 represents a group represented by -CH= or a group represented by -N=. Z 2 When there are multiple groups, they may be the same or different. R A represents a hydrogen atom or a primary substituent. AWhen there are multiple, they may be the same or different.

[0122] The content of the structural unit (A) contained in the polymer compound (A) may be within a range that allows the polymer compound (A) to exhibit its functions. The content of the structural unit (A) contained in the polymer compound (A) is, for example, 0.01 to 100 mol % relative to the total content of the structural units contained in the polymer compound (A). Since this reduces the driving voltage of the light-emitting device of the present disclosure, the content is preferably 0.1 to 99 mol %, more preferably 0.5 to 90 mol %, even more preferably 1 to 70 mol %, particularly preferably 5 to 50 mol %, and especially preferably 10 to 30 mol %. The polymer compound (A) may contain only one type of structural unit (A), or may contain two or more types of structural units (A).

[0123] The polymer compound (A) preferably further contains at least one structural unit selected from the group consisting of structural units represented by the formula (X) described below and structural units represented by the formula (Y) described below, because this reduces the driving voltage of the light-emitting device of the present disclosure. That is, the polymer compound (A) is preferably a polymer compound containing the structural unit (A) and at least one structural unit selected from the group consisting of structural units represented by the formula (X) described below and structural units represented by the formula (Y) described below. When the polymer compound (A) contains the structural unit (A) and at least one structural unit selected from the group consisting of the structural unit represented by the formula (X) described below and the structural unit represented by the formula (Y) described below, it is preferable that the structural unit (A) is different from the structural unit represented by the formula (X) described below and the structural unit represented by the formula (Y) described below. It is preferable that the polymer compound (A) further contains a structural unit represented by the formula (Y) described below, since this leads to a lower driving voltage of the light-emitting device of the present disclosure. The polymer compound (A) preferably further contains a structural unit represented by the formula (X) described below, because the polymer compound (A) has excellent hole transport properties and the driving voltage of the light-emitting device of the present disclosure is lowered. is preferred. It is preferable that the polymer compound (A) further contains a structural unit represented by the below-described formula (X) and a structural unit represented by the below-described formula (Y), since this will provide the polymer compound (A) with excellent hole transport properties and will lower the driving voltage of the light-emitting element of the present disclosure.

[0124] When the polymer compound (A) contains a structural unit represented by the formula (X) described below, the content of the structural unit represented by the formula (X) described below may be within a range that allows the polymer compound (A) to function. When the polymer compound (A) contains a structural unit represented by the formula (X) described below, the content of the structural unit represented by the formula (X) described below relative to the total content of structural units contained in the polymer compound (A) is, for example, 0.01 to 99.9 mol %, and is preferably 0.05 to 90 mol %, more preferably 0.1 to 70 mol %, even more preferably 0.2 to 50 mol %, particularly preferably 0.5 to 30 mol %, and particularly preferably 1 to 10 mol %, because this provides excellent hole transport properties for the polymer compound (B) and reduces the driving voltage of the light-emitting device of the present disclosure. The polymer compound (A) may contain only one type of constitutional unit represented by formula (X), or may contain two or more types.

[0125] When the polymer compound (A) contains a structural unit represented by formula (Y), the content of the structural unit represented by formula (Y) may be within a range that allows the polymer compound (A) to function. When the polymer compound (A) contains a structural unit represented by formula (Y), the content of the structural unit represented by formula (Y) relative to the total content of structural units contained in the polymer compound (A) is, for example, 0.1 to 99.99 mol %, and since this further reduces the driving voltage of the light-emitting device of the present disclosure, the content is preferably 1 to 99.9 mol %, more preferably 10 to 99.5 mol %, even more preferably 30 to 99 mol %, particularly preferably 50 to 95 mol %, and especially preferably 70 to 90 mol %. The polymer compound (A) may contain only one type of constitutional unit represented by formula (Y), or may contain two or more types.

[0126] When the polymer compound (A) contains a structural unit represented by formula (X) and / or a structural unit represented by formula (Y), and the structural unit (A), the total content of the structural unit represented by formula (X), the structural unit represented by formula (Y), and the structural unit (A) may be within a range that allows the polymer compound (A) to function. When the polymer compound (A) contains a structural unit represented by formula (X) and / or a structural unit represented by formula (Y), and the structural unit (A), the total content of the structural unit represented by formula (X), the structural unit represented by formula (Y), and the structural unit (A) is, for example, 1 to 100 mol% relative to the total content of the structural units contained in the polymer compound (A). Since the hole transport properties of the polymer compound (A) are excellent and the driving voltage of the light-emitting device of the present disclosure is lower, the total content is preferably 10 to 100 mol%, more preferably 30 to 100 mol%, even more preferably 50 to 100 mol%, particularly preferably 70 to 100 mol%, and particularly preferably 90 to 100 mol%.

[0127] Examples of the polymer compound (A) include polymer compounds AP-1 to AP-4. Here, "other" refers to structural units other than the structural unit (A), the structural unit represented by formula (X), and the structural unit represented by formula (Y).

[0128] [Table 2]

[0129] The polymer compound (A) may be any of a block copolymer, a random copolymer, an alternating copolymer, a graft copolymer, or other forms, but is preferably a copolymer obtained by copolymerizing a plurality of raw material monomers.

[0130] Examples and preferred ranges of the polystyrene-equivalent number average molecular weight of the polymer compound (A) are the same as the examples and preferred ranges of the polystyrene-equivalent number average molecular weight of the first polymer compound described below. Examples and preferred ranges of the polystyrene-equivalent weight average molecular weight of the polymer compound (A) are the same as the examples and preferred ranges of the polystyrene-equivalent weight average molecular weight of the polymer compound of the light-emitting layer B2 described below.

[0131] (Method for producing polymer compound (A)) The polymer compound (A) can be produced by the same method as the method for producing the polymer compound of the light-emitting layer B2 described below.

[0132] <Light-emitting layer B2> Since the driving voltage of the light-emitting device of the present disclosure will be lower, the light-emitting layer (B) is preferably a layer (hereinafter also referred to as "light-emitting layer B2") containing compound (B) and at least one compound selected from the group consisting of a low-molecular-weight compound represented by formula (H-1), and a polymer compound containing at least one structural unit selected from the group consisting of a structural unit represented by formula (X) and a structural unit represented by formula (Y).

[0133] In this specification, a polymer compound contained in the light-emitting layer B2 and including at least one structural unit selected from the group consisting of structural units represented by formula (X) and structural units represented by formula (Y) will also be referred to as the "polymer compound of the light-emitting layer B2". In this specification, the low molecular weight compound represented by formula (H-1) contained in the light-emitting layer B2 and the polymer compound of the light-emitting layer B2 will hereinafter be collectively referred to as the "compound of the light-emitting layer B2." That is, the light-emitting layer B2 is a layer containing the compound (B) and the compound of the light-emitting layer B2. The light-emitting layer B2 may contain only one kind of compound (B) and one kind of compound of the light-emitting layer B2, or may contain two or more kinds of compounds.

[0134] The total content of compound (B) in light-emitting layer B2 and the compounds of light-emitting layer B2 may be within a range that allows the light-emitting layer B2 to function properly. The total content of compound (B) in light-emitting layer B2 and the compounds of light-emitting layer B2 may be, for example, 0.01 to 100% by mass based on the total amount of light-emitting layer B2, and is preferably 1 to 99.9% by mass, more preferably 10 to 99.9% by mass, even more preferably 30 to 99% by mass, particularly preferably 50 to 95% by mass, and especially preferably 70 to 90% by mass, since this reduces the driving voltage of the light-emitting device of the present disclosure.

[0135] The content of compound (B) in light-emitting layer B2 may be within a range that allows the light-emitting layer B2 to function as such. When the total content of compound (B) and the compounds in light-emitting layer B2 is taken as 100 parts by mass, the content of compound (B) in light-emitting layer B2 is, for example, 0.01 to 99 parts by mass, and is preferably 0.05 to 90 parts by mass, more preferably 0.1 to 70 parts by mass, even more preferably 0.2 to 50 parts by mass, particularly preferably 0.5 to 30 parts by mass, and especially preferably 1 to 10 parts by mass, since this further reduces the driving voltage of the light-emitting device of the present disclosure.

[0136] In the light-emitting layer B2, the compound of the light-emitting layer B2 preferably interacts physically, chemically, or electrically with the compound (B). 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 the present disclosure. In the light-emitting element of the present disclosure, taking the light-emitting material as an example, the compound in the light-emitting layer B2 and the compound (B) electrically interact with each other, and electrical energy is efficiently transferred from the compound in the light-emitting layer B2 to the compound (B), which allows the compound (B) to emit light more efficiently, thereby reducing the driving voltage of the light-emitting element of the present disclosure.

[0137] From the above viewpoint, in the light-emitting layer B2, the driving voltage of the light-emitting device of the present disclosure becomes lower, so it is preferable that the compound of the light-emitting layer B2 has at least one function selected from hole injection property, hole transport property, electron injection property, and electron transport property. From the above viewpoint, in the light-emitting layer B2, as an example of a light-emitting material, the compound (B) preferably has light-emitting properties, since this lowers the driving voltage of the light-emitting device of the present disclosure. From the above viewpoint, in the light-emitting layer B2, it is preferable that the lowest excited singlet state (S1) of the compound of the light-emitting layer B2 has a higher energy level than the lowest excited singlet state (S1) of the compound (B), since this results in a lower driving voltage of the light-emitting element of the present disclosure. From the above viewpoint, in the light-emitting layer B2, it is preferable that the lowest excited triplet state (T1) of the compound of the light-emitting layer B2 has a higher energy level than the lowest excited triplet state (T1) of the compound (B), since this results in a lower driving voltage of the light-emitting element of the present disclosure.

[0138] The compound for the light-emitting layer B2 is preferably one that is soluble in a solvent capable of dissolving the compound (B), since the light-emitting device of the present disclosure can be produced by a wet process.

[0139] [Compounds for the light-emitting layer B2] The compound of the light-emitting layer B2 is at least one selected from the group consisting of low-molecular-weight compounds represented by formula (H-1) and high-molecular-weight compounds of the light-emitting layer B2. In the compound of the light-emitting layer B2, examples and preferred ranges of the low-molecular-weight compound represented by formula (H-1) are the same as the examples and preferred ranges of the low-molecular-weight compound represented by formula (H-1) contained in the first electron-transport layer and the second electron-transport layer described below.

[0140] [Polymer compound of light-emitting layer B2] The polymer compound of the light-emitting layer B2 is preferably a polymer compound different from the polymer compound (A) and the polymer compound (B), and more preferably a polymer compound that does not contain the structural unit (A) or the structural unit (B).

[0141] The polymer compound of the light-emitting layer B2 preferably contains a structural unit represented by the formula (X) described below, since this provides the polymer compound of the light-emitting layer B2 with excellent hole transport properties and also reduces the driving voltage of the light-emitting device of the present disclosure. When the polymer compound of light-emitting layer B2 contains a structural unit represented by formula (X), the content of the structural unit represented by formula (X) contained in the polymer compound of light-emitting layer B2 may be within a range that allows the polymer compound of light-emitting layer B2 to function as a functional group. When the polymer compound of light-emitting layer B2 contains a structural unit represented by formula (X), the content of the structural unit represented by formula (X) contained in the polymer compound of light-emitting layer B2 is, for example, 0.01 to 100 mol % relative to the total content of structural units contained in the polymer compound of light-emitting layer B2. Because the polymer compound of light-emitting layer B2 has excellent hole-transport properties and the driving voltage of the light-emitting device of the present disclosure is lower, the content is preferably 0.05 to 90 mol %, more preferably 0.1 to 70 mol %, even more preferably 0.2 to 50 mol %, particularly preferably 0.5 to 30 mol %, and especially preferably 1 to 10 mol %. In the polymer compound of the light-emitting layer B2, the structural unit represented by formula (X) may be contained in one type only, or in two or more types.

[0142] In the polymer compound of the light-emitting layer B2, examples and preferred ranges of the structural unit represented by formula (X) are the same as the examples and preferred ranges of the structural unit represented by formula (X) in the first electron-transport layer and the second electron-transport layer described below.

[0143] The polymer compound of the light-emitting layer B2 preferably contains a structural unit represented by formula (Y), since this reduces the driving voltage of the light-emitting device of the present disclosure.

[0144] When the polymer compound of light-emitting layer B2 contains a structural unit represented by formula (Y), the content of the structural unit represented by formula (Y) contained in the polymer compound of light-emitting layer B2 may be within a range that allows the polymer compound of light-emitting layer B2 to function as a functional group. When the polymer compound of light-emitting layer B2 contains a structural unit represented by formula (Y), the content of the structural unit represented by formula (Y) contained in the polymer compound of light-emitting layer B2 is, for example, 1 to 100 mol % relative to the total content of structural units contained in the polymer compound of light-emitting layer B2. Because this further reduces the driving voltage of the light-emitting device of the present disclosure, the content is preferably 10 to 100 mol %, more preferably 30 to 100 mol %, even more preferably 50 to 100 mol %, particularly preferably 70 to 100 mol %, and especially preferably 90 to 100 mol %. In the polymer compound of the light-emitting layer B2, the structural unit represented by formula (Y) may be contained in one type only, or in two or more types.

[0145] In the polymer compound of the light-emitting layer B2, examples and preferred ranges of the structural unit represented by formula (Y) are the same as the examples and preferred ranges of the structural unit represented by formula (Y) in the first electron-transport layer and the second electron-transport layer described below.

[0146] The polymer compound of the light-emitting layer B2 preferably contains a structural unit represented by formula (Y) and a structural unit represented by formula (X), since this provides excellent hole transport properties for the polymer compound of the light-emitting layer B2 and reduces the driving voltage of the light-emitting device of the present disclosure. When the polymer compound of light-emitting layer B2 contains a structural unit represented by formula (Y) and a structural unit represented by formula (X), the total content of the structural unit represented by formula (Y) and the structural unit represented by formula (X) contained in the polymer compound of light-emitting layer B2 may be within a range that allows the polymer compound of light-emitting layer B2 to function as intended. When the polymer compound of light-emitting layer B2 contains a structural unit represented by formula (Y) and a structural unit represented by formula (X), the total content of the structural unit represented by formula (Y) and the structural unit represented by formula (X) contained in the polymer compound of light-emitting layer B2 is, for example, 1 to 100 mol%, preferably 10 to 100 mol%, more preferably 30 to 100 mol%, even more preferably 50 to 100 mol%, particularly preferably 70 to 100 mol%, and especially preferably 90 to 100 mol%, because this provides excellent hole-transport properties for the polymer compound of light-emitting layer B2 and lowers the driving voltage of the light-emitting device of the present disclosure.

[0147] Examples of the polymer compound for the light-emitting layer B2 include polymer compounds HP-1 to HP-3.

[0148] [Table 3]

[0149] The polymer compound of the light-emitting layer B2 may be any of a block copolymer, a random copolymer, an alternating copolymer, a graft copolymer, or other forms, but is preferably a copolymer obtained by copolymerizing multiple types of raw material monomers.

[0150] The number average molecular weight of the polymer compound of the light-emitting layer B2 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 ~2×10 5 The weight average molecular weight of the first polymer compound in terms of polystyrene is preferably 1×10 4 ~2×10 6and more preferably 2×10 4 ~1×10 6 and more preferably 5 × 10 4 ~5×10 5 is.

[0151] (Method for producing polymer compound for light-emitting layer B2) The polymer compound of the light-emitting layer B2 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 liquid separation, or adding the reaction solution after the polymerization reaction to a lower alcohol such as methanol, filtering the precipitate, and then drying the precipitate, either alone or in combination. In this case, the product can be purified by a conventional method such as recrystallization, reprecipitation, continuous extraction using a Soxhlet extractor, or column chromatography.

[0152] <Light-emitting layer B3> The light-emitting layer (B) is preferably a layer containing the compound (A), the compound (B), and the compound of the light-emitting layer B2 (hereinafter also referred to as "light-emitting layer B3"), since this results in a lower driving voltage for the light-emitting element of the present disclosure. The light-emitting layer B3 may contain only one kind or two or more kinds of each of the compound (A), the compound (B) and the compound of the light-emitting layer B2.

[0153] The total content of compound (A), compound (B), and the compounds of light-emitting layer B2 in light-emitting layer B3 may be within a range that allows the light-emitting layer B3 to function properly. The total content of compound (A), compound (B), and the compounds of light-emitting layer B2 in light-emitting layer B3 may be, for example, 1 to 100% by mass based on the total amount of light-emitting layer B3, 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, since this reduces the driving voltage of the light-emitting device of the present disclosure.

[0154] The total content of compound (A) and compound (B) in light-emitting layer B3 may be within a range that allows the light-emitting layer B3 to function properly. When the total content of compound (A), compound (B), and the compounds in light-emitting layer B2 is taken as 100 parts by mass, the total content of compound (A) and compound (B) in light-emitting layer B3 is, for example, 0.01 to 99.9 parts by mass, and is preferably 0.1 to 99 parts by mass, more preferably 0.5 to 90 parts by mass, even more preferably 1 to 70 parts by mass, particularly preferably 5 to 50 parts by mass, and especially preferably 10 to 30 parts by mass, since this further reduces the driving voltage of the light-emitting device of the present disclosure.

[0155] The content of compound (B) in light-emitting layer B3 may be within a range that allows the light-emitting layer B3 to function properly. When the total content of compound (A) and compound (B) is taken as 100 parts by mass, the content of compound (B) in light-emitting layer B3 is, for example, 0.01 to 99 parts by mass, and is preferably 0.05 to 90 parts by mass, more preferably 0.1 to 70 parts by mass, even more preferably 0.5 to 50 parts by mass, particularly preferably 1 to 30 parts by mass, and especially preferably 2 to 20 parts by mass, since this further reduces the driving voltage of the light-emitting device of the present disclosure.

[0156] In the light-emitting layer B3, the compound (A), the compound (B), and the compound in the light-emitting layer B2 preferably interact physically, chemically, or electrically. This interaction makes it possible to improve or adjust the light-emitting properties, charge transport properties, or charge injection properties of the light-emitting layer B3, for example, and thereby reduce the driving voltage of the light-emitting device of the present disclosure.

[0157] Taking the light-emitting material in the light-emitting layer B3 as an example, the compound in the light-emitting layer B2, the compound (A), and the compound (B) interact electrically, and electrical energy is efficiently transferred from the compound in the light-emitting layer B2 to the compound (A), and further, electrical energy is efficiently transferred from the compound (A) to the compound (B), which allows the compound (B) to emit light more efficiently, thereby reducing the driving voltage of the light-emitting element of the present disclosure.

[0158] From the above viewpoint, in the light-emitting layer B3, the driving voltage of the light-emitting device of the present disclosure becomes lower, so it is more preferable that the compound of the light-emitting layer B2 has at least one function selected from hole injection property, hole transport property, electron injection property, and electron transport property. From the above viewpoint, in the light-emitting layer B3, it is more preferable that the compound (A) 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 lower driving voltage of the light-emitting device of the present disclosure. From the above viewpoint, it is more preferable that the compound (B) in the light-emitting layer B3 has light-emitting properties, since this leads to a lower driving voltage of the light-emitting device of the present disclosure. From the above viewpoint, in the light-emitting layer B3, it is preferable that the lowest excited singlet state (S1) of the compound in the light-emitting layer B2 has a higher energy level than the lowest excited singlet state (S1) of the compound (A), since this results in a lower driving voltage of the light-emitting element of the present disclosure. From the above viewpoint, in the light-emitting layer B3, it is preferable that the lowest excited singlet state (S1) of the compound in the light-emitting layer B2 has a higher energy level than the lowest excited singlet state (S1) of the compound (B), since this results in a lower driving voltage of the light-emitting element of the present disclosure. From the above viewpoint, in the light-emitting layer B3, it is preferable that the lowest excited singlet state (S1) of the compound (A) has a higher energy level than the lowest excited singlet state (S1) of the compound (B), since this lowers the driving voltage of the light-emitting element of the present disclosure. From the above viewpoint, in the light-emitting layer B3, it is preferable that the lowest excited triplet state (T1) of the compound in the light-emitting layer B2 has a higher energy level than the lowest excited triplet state (T1) of the compound (A), since this results in a lower driving voltage of the light-emitting element of the present disclosure. From the above viewpoint, in the light-emitting layer B3, it is preferable that the lowest excited triplet state (T1) of the compound in the light-emitting layer B2 has a higher energy level than the lowest excited triplet state (T1) of the compound (B), since this results in a lower driving voltage of the light-emitting element of the present disclosure. From the above viewpoint, in the light-emitting layer B3, it is preferable that the lowest excited triplet state (T1) of the compound (A) has a higher energy level than the lowest excited triplet state (T1) of the compound (B), since this lowers the driving voltage of the light-emitting element of the present disclosure.

[0159] The compound of the light-emitting layer B2 is preferably one that is soluble in a solvent capable of dissolving the compound (B) and the compound (A), since the light-emitting device of the present disclosure can be produced by a wet method.

[0160] In the light-emitting layer B2 and the light-emitting layer B3, the compound of the light-emitting layer B2 is preferably a host material, an assist dopant material, or a dopant material, more preferably a host material or an assist dopant material, and even more preferably a host material, because the driving voltage of the light-emitting device of the present disclosure is lowered. In the light-emitting layer B1 and the light-emitting layer B3, the compound (A) is preferably a host material, an assist dopant material, or a dopant material, since this lowers the driving voltage of the light-emitting device of the present disclosure. In the light-emitting layer B1 and the light-emitting layer B3, the metal complex represented by formula (1) is preferably a host material, an assist dopant material, or a dopant material, more preferably an assist dopant material or a dopant material, and even more preferably an assist dopant material, because the driving voltage of the light-emitting element of the present disclosure is lower. In the light-emitting layer B1 and the light-emitting layer B3, the polymer compound (A) is preferably a host material, an assist dopant material, or a dopant material, more preferably a host material or an assist dopant material, and even more preferably an assist dopant material, because this reduces the driving voltage of the light-emitting device of the present disclosure. In the light-emitting layer B1 and the light-emitting layer B3, the polymer compound (A) may have at least one function of a host material, an assist dopant material, and a dopant material, or may have at least two functions of a host material, an assist dopant material, and a dopant material, or may have three functions of a host material, an assist dopant material, and a dopant material. In the light-emitting layer (B) (for example, light-emitting layers B1 to B3), the compound (B) is preferably a host material, an assist dopant material, or a dopant material, since this lowers the driving voltage of the light-emitting device of the present disclosure. In the light-emitting layer (B) (for example, light-emitting layers B1 to B3), the low-molecular-weight compound (B) lowers the driving voltage of the light-emitting device of the present disclosure, and therefore is preferably used as a host material, an assist dopant material, or the like. Preferably, the compound is an assist dopant material or a dopant material, more preferably an assist dopant material or a dopant material, and even more preferably a dopant material. In the light-emitting layer (B) (for example, light-emitting layers B1 to B3), the polymer compound (B) is preferably a host material, an assist dopant material, or a dopant material, more preferably a host material or a dopant material, and even more preferably a dopant material, because this lowers the driving voltage of the light-emitting device of the present disclosure. In the light-emitting layer (B) (for example, light-emitting layers B1 to B3), the polymer compound (B) may have at least one function of a host material, an assist dopant material, and a dopant material, or may have at least two functions of a host material, an assist dopant material, and a dopant material, or may have three functions of a host material, an assist dopant material, and a dopant material.

[0161] In the light-emitting device of the present disclosure, the host material is preferably a material that physically, chemically, or electrically interacts with the assist dopant material. In the light-emitting device of the present disclosure, the host material is preferably a material that physically, chemically, or electrically interacts with the dopant material. In the light-emitting device of the present disclosure, the assist dopant material is preferably a material that physically, chemically, or electrically interacts with the dopant material. In the light-emitting device of the present disclosure, the host material, the assist dopant material, and the dopant material preferably interact physically, chemically, or electrically. These interactions make it possible to improve or adjust, for example, the light-emitting properties, charge transport properties, or charge injection properties of the light-emitting device of the present disclosure, and to lower the driving voltage of the light-emitting device of the present disclosure.

[0162] In the light-emitting element of the present disclosure, taking the light-emitting material as an example, the host material, the assist dopant material, and the dopant material electrically interact with each other, and electrical energy is efficiently transferred from the host material to the assist dopant material, and further, electrical energy is efficiently transferred from the assist dopant material to the dopant material, thereby allowing the dopant material to emit light more efficiently, and the driving voltage of the light-emitting element of the present disclosure can be reduced.

[0163] From the above viewpoint, in the light-emitting element of the present disclosure, it is more preferable that the host material 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 lower driving voltage of the light-emitting element of the present disclosure. From the above viewpoint, in the light-emitting element of the present disclosure, it is more preferable that the assist dopant material has at least one function selected from hole injection property, hole transport property, electron injection property, and electron transport property, since this will result in a lower driving voltage for the light-emitting element of the present disclosure. From the above viewpoint, in the light-emitting element of the present disclosure, it is preferable that the dopant material has luminescent properties, since this leads to a lower driving voltage of the light-emitting element of the present disclosure. From the above viewpoint, in the light-emitting element of the present disclosure, 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 assist dopant material, since this results in a lower driving voltage for the light-emitting element of the present disclosure. From the above viewpoint, in the light-emitting element of the present disclosure, 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 dopant material, since this results in a lower driving voltage for the light-emitting element of the present disclosure. From the above viewpoint, in the light-emitting element of the present disclosure, it is preferable that the lowest excited singlet state (S1) of the assist dopant material has a higher energy level than the lowest excited singlet state (S1) of the dopant material, since this results in a lower driving voltage for the light-emitting element of the present disclosure. From the above viewpoint, in the light-emitting element of the present disclosure, 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 assist dopant material, since this results in a lower driving voltage for the light-emitting element of the present disclosure. From the above viewpoint, in the light-emitting element of the present disclosure, 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 dopant material, since this results in a lower driving voltage of the light-emitting element of the present disclosure. From the above viewpoint, in the light-emitting element of the present disclosure, it is preferable that the lowest excited triplet state (T1) of the assist dopant material has a higher energy level than the lowest excited triplet state (T1) of the dopant material, since this results in a lower driving voltage for the light-emitting element of the present disclosure.

[0164] In the light-emitting device of the present disclosure, when the light-emitting layer (B) is a layer containing an assist dopant material and a dopant material, the total content of the assist dopant material and the dopant material in the light-emitting layer (B) may be within a range that allows the light-emitting layer (B) to function properly. In the light-emitting device of the present disclosure, when the light-emitting layer (B) is a layer containing an assist dopant material and a dopant material, the total content of the assist dopant material and the dopant material in the light-emitting layer (B) may be, for example, 0.01 to 100% by mass based on the total amount of the light-emitting layer (B), and is preferably 0.1 to 99% by mass, more preferably 0.5 to 90% by mass, even more preferably 1 to 70% by mass, particularly preferably 5 to 50% by mass, and particularly preferably 10 to 30% by mass, since this reduces the driving voltage of the light-emitting device of the present disclosure. In the light-emitting device of the present disclosure, when the light-emitting layer (B) is a layer containing an assist dopant material and a dopant material, the content of the dopant material in the light-emitting layer (B) may be within a range that allows the light-emitting layer (B) to function properly. In the light-emitting device of the present disclosure, when the light-emitting layer (B) is a layer containing an assist dopant material and a dopant material, the content of the dopant material in the light-emitting layer (B) is, for example, 0.01 to 99 parts by mass, where the total content of the assist dopant material and the dopant material is taken as 100 parts by mass. Since this further reduces the driving voltage of the light-emitting device of the present disclosure, the content is preferably 0.05 to 90 parts by mass, more preferably 0.1 to 70 parts by mass, even more preferably 0.5 to 50 parts by mass, particularly preferably 1 to 30 parts by mass, and particularly preferably 2 to 20 parts by mass.

[0165] In the light-emitting device of the present disclosure, when the light-emitting layer (B) is a layer containing a host material and a dopant material, the total content of the host material and the dopant material in the light-emitting layer (B) may be within a range that allows the light-emitting layer (B) to function properly. In the light-emitting device of the present disclosure, when the light-emitting layer (B) is a layer containing a host material and a dopant material, the total content of the host material and the dopant material in the light-emitting layer (B) may be, for example, 0.1 to 100% by mass based on the total amount of the light-emitting layer (B). In order to further reduce the driving voltage of the light-emitting device of the present disclosure, the total content of the host material and the dopant material is preferably 1 to 99.9% by mass, more preferably 10 to 99.9% by mass, even more preferably 30 to 99% by mass, particularly preferably 50 to 95% by mass, and particularly preferably 70 to 90% by mass. In the light-emitting device of the present disclosure, when the light-emitting layer (B) is a layer containing a host material and a dopant material, the content of the dopant material in the light-emitting layer (B) may be within a range that allows the light-emitting layer (B) to function properly. In the light-emitting device of the present disclosure, when the light-emitting layer (B) is a layer containing a host material and a dopant material, the content of the dopant material in the light-emitting layer (B) is, for example, 0.01 to 99 parts by mass, where the total content of the host material and the dopant material is taken as 100 parts by mass. Since this further reduces the driving voltage of the light-emitting device of the present disclosure, the content is preferably 0.05 to 90 parts by mass, more preferably 0.1 to 70 parts by mass, even more preferably 0.2 to 50 parts by mass, particularly preferably 0.5 to 30 parts by mass, and particularly preferably 1 to 10 parts by mass.

[0166] In the light-emitting device of the present disclosure, when the light-emitting layer (B) is a layer containing a host material, an assist dopant material, and a dopant material, the total content of the host material, the assist dopant material, and the dopant material in the light-emitting layer (B) may be within a range that allows the function of the light-emitting layer to be exhibited. In the light-emitting device of the present disclosure, when the light-emitting layer (B) is a layer containing a host material, an assist dopant material, and a dopant material, the total content of the host material, the assist dopant material, and the dopant material in the light-emitting layer (B) may be, for example, 1 to 100 mass% based on the total amount of the light-emitting layer (B), and the driving voltage of the light-emitting device of the present disclosure will be lower. Therefore, it is preferably 10 to 100% by mass, more preferably 30 to 100% by mass, even more preferably 50 to 100% by mass, particularly preferably 70 to 100% by mass, and especially preferably 90 to 100% by mass. In the light-emitting device of the present disclosure, when the light-emitting layer (B) is a layer containing a host material, an assist dopant material, and a dopant material, the total content of the assist dopant material and the dopant material in the light-emitting layer (B) may be within a range that allows the light-emitting layer (B) to function properly. In the light-emitting device of the present disclosure, when the light-emitting layer (B) is a layer containing a host material, an assist dopant material, and a dopant material, the total content of the assist dopant material and the dopant material in the light-emitting layer (B) is, for example, 0.01 to 99.9 parts by mass, where the total content of the host material, the assist dopant material, and the dopant material is taken as 100 parts by mass. Since this further reduces the driving voltage of the light-emitting device of the present disclosure, the total content of the assist dopant material and the dopant material is preferably 0.1 to 99 parts by mass, more preferably 0.5 to 90 parts by mass, even more preferably 1 to 70 parts by mass, particularly preferably 5 to 50 parts by mass, and particularly preferably 10 to 30 parts by mass. In the light-emitting device of the present disclosure, when the light-emitting layer (B) is a layer containing a host material, an assist dopant material, and a dopant material, the total content of the dopant material in the light-emitting layer (B) may be within a range that allows the light-emitting layer (B) to function properly. In the light-emitting device of the present disclosure, when the light-emitting layer (B) is a layer containing a host material, an assist dopant material, and a dopant material, the content of the dopant material in the light-emitting layer (B) is, for example, 0.01 to 99 parts by mass, where the total content of the assist dopant material and the dopant material is taken as 100 parts by mass. Since this further reduces the driving voltage of the light-emitting device of the present disclosure, the content is preferably 0.05 to 90 parts by mass, more preferably 0.1 to 70 parts by mass, even more preferably 0.5 to 50 parts by mass, particularly preferably 1 to 30 parts by mass, and particularly preferably 2 to 20 parts by mass.

[0167] Since the light-emitting device of the present disclosure can be fabricated by a wet process, the assist dopant material is preferably soluble in a solvent capable of dissolving the dopant material.Since the light-emitting device of the present disclosure can be fabricated by a wet process, the host material is preferably soluble in a solvent capable of dissolving the assist dopant material and the dopant material.

[0168] [Composition of Light-Emitting Layer (B)] The light-emitting layer (B) may further contain 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. The light-emitting layer (B) may be a layer containing a composition (hereinafter also referred to as the "composition of the light-emitting layer (B)") containing the compound (B) and at least one selected from the group consisting of the compound (A), the compound of the light-emitting layer B2, 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 composition of the light-emitting layer (B), 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 compound (B). The composition of the light-emitting layer (B) may contain one or more of the compound (B), the compound (A), the compound of the light-emitting layer B2, the hole transport material, the hole injection material, the electron transport material, the electron injection material, the light-emitting material, and the antioxidant. In the composition for the light-emitting layer (B), the total content of the compound (B), the compound (A), the compound for the light-emitting layer B2, the hole transport material, the hole injection material, the electron transport material, the electron injection material, the light-emitting material, and the antioxidant may be within a range that allows the composition to function as the light-emitting layer (B). In the composition for the light-emitting layer (B), the total content of the compound (B), the compound (A), the compound for the light-emitting layer B2, the hole transport material, the hole injection material, the electron transport material, the electron injection material, the light-emitting material, and the antioxidant may be, for example, 1 to 100 mass%, 10 to 100 mass%, 30 to 100 mass%, more preferably 50 to 100 mass%, 70 to 100 mass%, or 90 to 100 mass%, based on the total amount of the first composition. % may also be used.

[0169] (hole transport material) Hole transport materials are classified into low molecular weight compounds and high molecular weight compounds. The hole transport material may have a crosslinking group. Examples of low molecular weight compounds include aromatic amine compounds such as triphenylamine and its derivatives, N,N'-di-1-naphthyl-N,N'-diphenylbenzidine (α-NPD), and N,N'-diphenyl-N,N'-di(m-tolyl)benzidine (TPD). 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 also be a compound to which an electron-accepting moiety is bonded, such as fullerene, tetrafluorotetracyanoquinodimethane, tetracyanoethylene, and trinitrofluorenone. When the composition of the light-emitting layer (B) contains a hole transport material, the content of the hole transport material is usually 1 to 10,000 parts by mass relative to 100 parts by mass of the content of the compound (B). The hole transport material may be used alone or in combination of two or more kinds.

[0170] (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. 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. Examples of the polymer compound include polyphenylene, polyfluorene, and derivatives thereof. The polymer compound may be doped with a metal. When the composition of the light-emitting layer (B) contains an electron transport material, the content of the electron transport material is usually 1 to 10,000 parts by mass, relative to 100 parts by mass of the content of the compound (B). The electron transporting materials may be used alone or in combination of two or more.

[0171] (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. Examples of low molecular weight compounds include metal phthalocyanines such as copper phthalocyanine; carbon; metal oxides such as molybdenum and tungsten; and metal fluorides such as lithium fluoride, sodium fluoride, cesium fluoride, and potassium fluoride. Examples of 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. When the composition of the light-emitting layer (B) contains a hole injection material and / or an electron injection material, the contents of the hole injection material and the electron injection material are each usually 1 to 10,000 parts by mass, relative to 100 parts by mass of the compound (B). The hole injection material and the electron injection material may each be used alone or in combination of two or more kinds.

[0172] Ion doping The hole injection material or the electron injection material may be doped with ions. When the electron 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. The type of ion doped into the hole injection material or electron injection material may be, for example, an anion for the hole injection material, or a cation for the 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.

[0173] (luminescent material) Light-emitting materials are classified into low molecular weight compounds and high molecular weight compounds. The light-emitting material may have a crosslinking group. Examples of low molecular weight compounds include naphthalene and its derivatives, anthracene and its derivatives, perylene and its derivatives, and phosphorescent compounds having iridium, platinum, or europium as a central metal. Examples of the polymer compound include polymer compounds containing a constitutional unit represented by formula (Y) described below and / or a constitutional unit represented by formula (X) described below. When the composition of the light-emitting layer (B) contains a light-emitting material, the content of the light-emitting material is usually 1 to 10,000 parts by mass, assuming that the content of the compound (B) is 100 parts by mass. The light-emitting materials may be used alone or in combination of two or more.

[0174] (antioxidant) The antioxidant may be any compound that is soluble in the same solvent as compound (B) and compound (A) and does not inhibit light emission and charge transport, and examples thereof include phenol-based antioxidants and phosphorus-based antioxidants. When an antioxidant is contained in the composition of the light-emitting layer (B), the content of the antioxidant is usually 0.00001 to 10 parts by mass relative to 100 parts by mass of the content of the compound (B). The antioxidants may be used alone or in combination of two or more.

[0175] [Ink for luminescent layer (B)] The light-emitting layer (B) can be formed, for example, using a composition containing the compound (B) and a solvent (hereinafter also referred to as "ink for the light-emitting layer (B)"). The ink for the light-emitting layer (B) may contain one kind of compound (B) and one kind of solvent, or two or more kinds of compounds (B) and solvents. The ink for the light-emitting layer (B) may further contain at least one selected from the group consisting of the compound (A), the compound for the light-emitting layer B2, a hole transport material, a hole injection material, an electron transport material, an electron injection material, a light-emitting material, and an antioxidant. The ink for the light-emitting layer (B) may contain one or more of the compound (A), the compound for the light-emitting layer (B2), 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, electron transport material, hole injection material, electron injection material, light emitting material, and antioxidant that may further be contained in the ink for the light emitting layer (B) 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 composition for the light emitting layer (B), respectively. 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 ink for the light emitting layer (B), is usually 1 to 10,000 parts by mass, based on 100 parts by mass of the compound (B). The content of the antioxidant, which may be further contained in the first ink, is usually 0. It is 0.00001 to 10 parts by mass.

[0176] The ink for the light-emitting layer (B) can be suitably used in the production of a light-emitting device using a wet 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, or nozzle coating. The viscosity of the ink for the light-emitting layer (B) may be adjusted depending on the type of wet method used. For example, when the first ink is used in a printing method in which a solution passes through a discharge device, such as inkjet printing, the viscosity of the first ink is preferably 1 to 20 mPa s at 25°C, since clogging and deflection during discharge are unlikely to occur.

[0177] The solvent contained in the ink for the light-emitting layer (B) is preferably a solvent that can dissolve or uniformly disperse the solid content in the ink. Examples of the solvent contained in the first ink include chlorine-based solvents, ether-based solvents, aromatic hydrocarbon-based solvents, aliphatic hydrocarbon-based solvents, ketone-based solvents, ester-based solvents, polyhydric alcohol-based solvents, alcohol-based solvents, sulfoxide-based solvents, amide-based solvents, and water. In the ink for the light-emitting layer (B), the content of the solvent is usually 1,000 to 10,000,000 parts by mass, assuming that the content of the compound (B) is 100 parts by mass. The solvent may be used alone or in combination of two or more kinds.

[0178] <First Electron Transport Layer and Second Electron Transport Layer> In the light-emitting element of the present disclosure, the first electron transport layer and the second electron transport layer are layers containing at least one selected from the group consisting of low molecular weight compounds represented by formula (H-1), low molecular weight compounds represented by formula (ET-1), low molecular weight compounds represented by formula (ET-2), and polymer compounds containing at least one structural unit selected from the group consisting of a structural unit having a group obtained by removing one or more hydrogen atoms from a low molecular weight compound represented by formula (ET-1) (hereinafter also referred to as "structural unit (ET-1)"), a structural unit having a group obtained by removing one or more hydrogen atoms from a low molecular weight compound represented by formula (ET-2) (hereinafter also referred to as "structural unit (ET-2)"), a structural unit represented by formula (X) (hereinafter also referred to as "structural unit (X)"), and a structural unit represented by formula (Y) (hereinafter also referred to as "structural unit (Y)"). However, at least one of the first electron transport layer and the second electron transport layer is a layer containing a polymer compound including at least one structural unit selected from the structural unit (ET-1), the structural unit (ET-2), the structural unit (X), and the structural unit (Y).

[0179] The first electron transport layer and the second electron transport layer preferably have different compositions, and the first electron transport layer and the second electron transport layer preferably do not contain the compound (B).

[0180] In this specification, the low molecular weight compounds represented by formula (H-1), (ET-1), and (ET-2) are hereinafter collectively referred to as "low molecular weight compounds (ET)." Hereinafter, polymeric compounds containing at least one structural unit selected from the group consisting of the structural unit (ET-1), the structural unit (ET-2), the structural unit (X), and the structural unit (Y) will also be collectively referred to as "polymeric compound (ET)." In the present specification, the low molecular weight compounds (ET) and the high molecular weight compounds (ET) are hereinafter collectively referred to as "compounds (ET)".

[0181] (Low molecular weight compound represented by formula (H-1)) The molecular weight of the low-molecular compound represented by formula (H-1) is such that the driving voltage of the light-emitting device of the present disclosure is further It is preferably 1×10 2 ~5×10 3 and more preferably 2×10 2 ~3×10 3 and more preferably 3×10 2 ~1.5×10 3 and particularly preferably 4 × 10 2 ~1×10 3 is. The low molecular weight compound represented by formula (H-1) is preferably a compound different from compound (B), and more preferably a compound that does not have a fused heterocyclic skeleton (b).

[0182] Ar H1 and Ar H2 The aryl group in the formula (I) 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 heptacyclic aromatic hydrocarbon, since this reduces the driving voltage of the light-emitting element of the present disclosure; more 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 pentacyclic aromatic hydrocarbon; and even 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, and these groups may have a substituent. Ar H1 and Ar H2The aryl group in the formula (I) is preferably a group in which one hydrogen atom directly bonded to an atom constituting a ring has been removed from benzene, naphthalene, anthracene, phenanthrene, dihydrophenanthrene, fluorene, benzanthracene, benzophenanthrene, benzofluorene, dibenzanthracene, dibenzophenanthrene, dibenzofluorene, indenofluorene, or benzofluoranthene, since this further reduces the driving voltage of the light-emitting element of the present disclosure, and more preferably benzene, naphthalene, anthracene, phenanthrene, dihydrophenanthrene, It is a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from phenanthrene, fluorene, benzanthracene, benzophenanthrene, or benzofluorene, more preferably a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from benzene, naphthalene, anthracene, phenanthrene, dihydrophenanthrene, or fluorene, particularly preferably a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from benzene, naphthalene, or anthracene, and these groups may have a substituent.

[0183] Ar H1 and Ar H2 The monovalent heterocyclic group in the formula (I) is preferably a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from a heterocyclic compound not containing a fused heterocyclic skeleton (b), and this group may have a substituent. H1 and Ar H2 In the monovalent heterocyclic group in the above, examples of heterocyclic compounds that do not contain a fused heterocyclic skeleton (b) include, for example, heterocyclic compounds that contain a boron atom and an oxygen atom, a sulfur atom, a selenium atom, sp 3 Examples of the heterocyclic compounds include those that do not contain at least one atom selected from the group consisting of carbon atoms and nitrogen atoms in the ring. Ar H1 and Ar H2The monovalent heterocyclic group in the formula (I) is preferably a group obtained by removing one hydrogen atom directly bonded to an atom constituting a ring from a monocyclic or bicyclic to heptacyclic heterocyclic compound (preferably a monocyclic or bicyclic to heptacyclic heterocyclic compound not containing a fused heterocyclic skeleton (b)), since this results in a lower driving voltage for the light-emitting element of the present disclosure, and more preferably a group obtained by removing one hydrogen atom directly bonded to an atom constituting a ring from a monocyclic or bicyclic to pentacyclic heterocyclic compound (preferably a monocyclic or bicyclic to pentacyclic heterocyclic compound not containing a fused heterocyclic skeleton (b)). It is a group in which one atom has been removed, 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 heterocyclic compound (preferably a monocyclic, bicyclic, or tricyclic heterocyclic compound not containing a fused heterocyclic skeleton (b)), and particularly preferably a group in which one hydrogen atom directly bonded to an atom constituting the ring has been removed from a tricyclic heterocyclic compound (preferably a tricyclic heterocyclic compound not containing a fused heterocyclic skeleton (b)), and these groups may have a substituent. Ar H1 and Ar H2 The monovalent heterocyclic group in the formula (I) is preferably furan, thiophene, oxadiazole, thiadiazole, pyrrole, diazole, triazole, pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, benzofuran, benzothiophene, indole, or azaine, because the driving voltage of the light-emitting element of the present disclosure is lower. and a group in which one hydrogen atom directly bonded to an atom constituting the ring has been removed from an indole, diazaindole, benzodiazole, benzothiadiazole, benzotriazole, dibenzofuran, dibenzothiophene, carbazole, azacarbazole, diazacarbazole, phenoxazine, phenothiazine, 9,10-dihydroacridine, 5,10-dihydrophenazine, azaanthracene, diazaanthracene, azaphenanthrene, diazaphenanthrene, benzocarbazole, azabenzocarbazole, diazabenzocarbazole, benzonaphthofuran, benzonaphthothiophene, dibenzocarbazole, indolocarbazole, indenocarbazole, azaindolocarbazole, diazaindenocarbazole, or diazaindenocarbazole, more preferably pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, and more preferably pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, dibenzofuran, dibenzothiophene, carbazole, azacarbazole, diazacarbazole, phenoxazine, phenothiazine, 9,10-dihydroacridine, 5,10-dihydrophenazine, benzocarbazole, azabenzocarbazole, diazabenzocarbazole, benzonaphthofuran, benzonaphthothiophene, dibenzocarbazole, indolocarbazole, indenocarbazole, azaindolocarbazole, diazaindenocarbazole, or diazaindenocarbazole, by removing one hydrogen atom directly bonded to an atom constituting the ring.It is a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from 10-dihydrophenazine, and is particularly preferably a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, dibenzofuran, dibenzothiophene, or carbazole, and is particularly preferably a group obtained by removing one hydrogen atom directly bonded to an atom constituting the ring from dibenzofuran, dibenzothiophene, or carbazole, and these groups may have a substituent.

[0184] Ar H1 and Ar H2 In the substituted amino group in the above, the substituent of the amino group is preferably an aryl group or a monovalent heterocyclic group, more preferably an aryl group, and these groups may further have a substituent. Examples and preferred ranges of the aryl group that is the substituent of the amino group are as follows: Ar H1 and Ar H2 Examples and preferred ranges of the aryl group in Ar are the same as those in Ar. H1 and Ar H2 The examples and preferred ranges of the monovalent heterocyclic group are the same as those in the above.

[0185] Since the driving voltage of the light-emitting device of the present disclosure is lower, Ar H1 and Ar H2 At least one of Ar is preferably an aryl group or a monovalent heterocyclic group, H1 and Ar H2 and more preferably both are an aryl group or a monovalent heterocyclic group, and these groups may have a substituent. Ar H1 and Ar H2As the aryl group and the monovalent heterocyclic group in the above, 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, or a monocyclic, bicyclic, or tricyclic heterocyclic compound (preferably a monocyclic, bicyclic, or tricyclic heterocyclic compound not containing a fused heterocyclic skeleton (b)), is preferred, since this results in a lower driving voltage for the light-emitting element of the present disclosure; a group in which one hydrogen atom directly bonded to an atom constituting the ring has been removed from benzene, naphthalene, fluorene, pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, dibenzofuran, dibenzothiophene, or carbazole is more preferred; a phenyl group, naphthyl group, fluorenyl group, carbazolyl group, dibenzothienyl group, or dibenzofuryl group is even more preferred; and a phenyl group, naphthyl group, or carbazolyl group is particularly preferred, and these groups may have a substituent.

[0186] Ar H1 and Ar H2 The substituent that may be substituted is preferably a halogen atom, a cyano group, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryloxy group, an aryl group, a monovalent heterocyclic group, or a substituted amino group, more preferably an alkyl group, a cycloalkyl group, an 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, and particularly preferably an alkyl group, a cycloalkyl group, or an aryl group, and these groups may further have a substituent. Ar H1 and Ar H2 Examples and preferred ranges of the aryl group, monovalent heterocyclic group and substituted amino group in the substituent that may be possessed by Ar are respectively H1 and Ar H2 The examples and preferred ranges of the aryl group, monovalent heterocyclic group and substituted amino group in the above are the same as those in the above.

[0187] Ar H1 and Ar H2The substituent that may be further substituted by the substituent that may be substituted by is preferably a halogen atom, a cyano group, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryloxy group, an aryl group, a monovalent heterocyclic group, or a substituted amino group, more preferably an alkyl group, a cycloalkyl group, an aryl group, a monovalent heterocyclic group, or a substituted amino group, even 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 substituted, but preferably do not further substituted. Ar H1 and Ar H2 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 Ar are respectively H1 and Ar H2 The examples and preferred ranges of the aryl group, monovalent heterocyclic group and substituted amino group in the above are the same as those in the above.

[0188] L H1 The divalent group in is preferably an alkylene group, a cycloalkylene group, an arylene group, a divalent heterocyclic group, or —N(R 0 )-, a group represented by -(O=)P(R 0 )-, a group represented by -O-, a group represented by -S-, a group represented by -S(=O)2-, or a group represented by -C(=O)-, and more preferably an alkylene group, a cycloalkylene group, an arylene group, a divalent heterocyclic group, -N(R 0 )-, a group represented by -O-, or a group represented by -S-, more preferably an alkylene group, a cycloalkylene group, an arylene group, or a divalent heterocyclic group, particularly preferably an arylene group or a divalent heterocyclic group, and these groups may have a substituent. L H1At least one of the divalent groups in the formula (I) is preferably an alkylene group, a cycloalkylene group, an arylene group, or a divalent heterocyclic group, and more preferably an arylene group or a divalent heterocyclic group, since this reduces the driving voltage of the light-emitting element of the present disclosure, and these groups may have a substituent.

[0189] L H1 In the divalent group represented by the formula (I), the arylene group is preferably a group obtained by removing two hydrogen atoms directly bonded to atoms constituting the ring from a monocyclic or bicyclic to heptacyclic aromatic hydrocarbon, since this reduces the driving voltage of the light-emitting element of the present disclosure; more preferably a group obtained by removing two hydrogen atoms directly bonded to atoms constituting the ring from a monocyclic or bicyclic to pentacyclic aromatic hydrocarbon; and even 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, and these groups may have a substituent. L H1 In the divalent group, the arylene group is preferably a group in which two hydrogen atoms directly bonded to atoms constituting a ring have been removed from benzene, naphthalene, anthracene, phenanthrene, dihydrophenanthrene, fluorene, benzanthracene, benzophenanthrene, benzofluorene, dibenzanthracene, dibenzophenanthrene, dibenzofluorene, indenofluorene, or benzofluoranthene, since this results in a lower driving voltage for the light-emitting element of the present disclosure, and more preferably benzene, naphthalene, anthracene, or phenanthrene. , dihydrophenanthrene, fluorene, benzanthracene, benzophenanthrene, or benzofluorene, 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, naphthalene, or anthracene, and these groups may have a substituent.

[0190] L H1In the divalent group in the formula (I), the divalent heterocyclic group is preferably a group obtained by removing two hydrogen atoms directly bonded to atoms (preferably carbon atoms) constituting the ring from a heterocyclic compound not containing a fused heterocyclic skeleton (b), and this group may have a substituent. H1 In the divalent group, heterocyclic compounds that do not contain a fused heterocyclic skeleton (b) in the divalent heterocyclic group include heterocyclic compounds that contain a boron atom and an oxygen atom, a sulfur atom, a selenium atom, sp 3 Examples of the heterocyclic compounds include those that do not contain at least one atom selected from the group consisting of carbon atoms and nitrogen atoms in the ring. L H1 In the divalent group in the formula (I), the divalent heterocyclic group is preferably a group obtained by removing two hydrogen atoms directly bonded to an atom (preferably a carbon atom) constituting a ring from a monocyclic or bicyclic to heptacyclic heterocyclic compound (preferably a monocyclic or bicyclic to heptacyclic heterocyclic compound not containing a fused heterocyclic skeleton (b)), since this reduces the driving voltage of the light-emitting element of the present disclosure, and more preferably a group obtained by removing two hydrogen atoms directly bonded to an atom (preferably a carbon atom) constituting a ring from a monocyclic or bicyclic to pentacyclic heterocyclic compound (preferably a monocyclic or bicyclic to pentacyclic heterocyclic compound not containing a fused heterocyclic skeleton (b)). More preferably, it is a group obtained by removing two hydrogen atoms directly bonded to an atom constituting a ring (preferably a carbon atom) from a monocyclic, bicyclic, or tricyclic heterocyclic compound (preferably a monocyclic, bicyclic, or tricyclic heterocyclic compound not containing a fused heterocyclic skeleton (b)), and particularly preferably, it is a group obtained by removing two hydrogen atoms directly bonded to an atom constituting a ring (preferably a carbon atom) from a tricyclic heterocyclic compound (preferably a tricyclic heterocyclic compound not containing a fused heterocyclic skeleton (b)), and these groups may have a substituent. L H1In the divalent group in the formula (I), a divalent heterocyclic group is preferably furan, thiophene, oxadiazole, thiadiazole, pyrrole, diazole, triazole, pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, benzofuran, benzothiophene, indole, azaindole, diazaindole, benzodiazole, benzothiadiazole, benzotriazole, dibenzofuran, dibenzothiophene, carbazole, azacarbazole, diazacarbazole, azaindenocarbazole, phenoxazine, phenothiazine, 9,10-dihydroacridine, 5,10-dihydrophenazine, azaanthracene, diazaanthracene, azaphenanthrene, diazaphenanthrene, benzocarbazole, azabenzocarbazole, diazabenzocarbazole, benzonaphthofuran, benzonaphthothiophene, dibenzocarbazole, indolocarbazole, indenocarbazole, azaindolocarbazole, diazaindolocarbazole, azaindenocarbazole, or diazaindenocarbazole and more preferably pyridine, diazabenzene, triazine, azanaphthalene, dibenzofuran, dibenzothiophene, carbazole, azacarbazole, diazacarbazole, phenoxazine, phenothiazine, 9,10-dihydroacridine, 5,10-dihydrophenazine, benzocarbazole, azabenzocarbazole, diazabenzocarbazole, benzonaphthofuran, benzonaphthothiophene, dibenzocarbazole, It is a group in which two hydrogen atoms directly bonded to atoms (preferably carbon atoms) constituting the ring are removed from indolocarbazole, indenocarbazole, azaindolocarbazole, diazaindenocarbazole, or diazaindenocarbazole, and more preferably pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, dibenzofuran, dibenzothiophene, carbazole, azacarbazole, diazacarbazole, phenoxazine, phenothiazine, 9,10-dihydroacridine, or 5,It is a group obtained by removing two hydrogen atoms directly bonded to atoms (preferably carbon atoms) constituting the ring from 10-dihydrophenazine, and is particularly preferably a group obtained by removing two hydrogen atoms directly bonded to atoms (preferably carbon atoms) constituting the ring from pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, dibenzofuran, dibenzothiophene, or carbazole, and is particularly preferably a group obtained by removing two hydrogen atoms directly bonded to atoms (preferably carbon atoms) constituting the ring from dibenzofuran, dibenzothiophene, or carbazole, and these groups may have a substituent.

[0191] L H1 In the divalent group, the alkylene group is preferably a methylene group, an ethylene group, or a propylene group, more preferably a methylene group, and these groups may have a substituent.

[0192] L H1 Examples of the substituents that may be possessed by Ar and the preferred range thereof are as follows: H1 and Ar H2 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.

[0193] L H1 In the divalent group in 0 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. L H1 In the divalent group in 0 Examples and preferred ranges of the aryl group and the monovalent heterocyclic group in H1 and Ar H2 The examples and preferred ranges of the aryl group and monovalent heterocyclic group in the above are the same as those in the above. L H1 In the divalent group in 0 Examples of the substituents that may be possessed by Ar and the preferred range thereof are as follows: H1 and Ar H2The 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.

[0194] n H1 is usually an integer of 0 or more and 10 or less, preferably an integer of 0 or more and 7 or less, more preferably an integer of 1 or more and 5 or less, even more preferably an integer of 1 or more and 3 or less, and particularly preferably 1 or 2.

[0195] Ar H1 and Ar H2 may be bonded directly or via a divalent group to form a ring, but it is preferable that they do not form a ring, as this facilitates the synthesis of the low molecular weight compound represented by formula (H-1). Ar H1 and Ar H2 When the groups bond to each other via a divalent group to form a ring, the divalent group is preferably an alkylene group, a cycloalkylene group, an arylene group, a divalent heterocyclic group, or —N(R 0 )-, a group represented by -(O=)P(R 0 )-, a group represented by -O-, a group represented by -S-, a group represented by -S(=O)2-, or a group represented by -C(=O)-, and more preferably an alkylene group, a cycloalkylene group, -N(R 0 )-, a group represented by -O-, or a group represented by -S-, and more preferably an alkylene group, a group represented by -O-, or a group represented by -S-, and these groups may have a substituent. Ar H1 and Ar H2 and L are bonded via a divalent group to form a ring, examples and preferred ranges of the arylene group, divalent heterocyclic group and alkylene group in the divalent group are respectively H1 The examples and preferred ranges of the arylene group, divalent heterocyclic group and alkylene group in the above are the same as those in the above. Ar H1 and Ar H2 and R in the divalent group when they are bonded to form a ring via a divalent group 0 Examples and preferred ranges of L H1 R in the divalent group0 The examples and preferred ranges are the same as those of the above. Ar H1 and Ar H2 and form a ring via a divalent group, Examples of the substituents that the valent group may have and the preferred ranges thereof are Ar H1 and Ar H2 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.

[0196] L H1 and Ar H1 and may be bonded directly or via a divalent group to form a ring, but it is preferable that they do not form a ring, as this facilitates the synthesis of the low molecular weight compound represented by formula (H-1). H1 and Ar H1 When Ar and Ar are bonded via a divalent group to form a ring, examples and preferred ranges of the divalent group include Ar H1 and Ar H2 and are bonded via a divalent group to form a ring, the examples and preferred ranges of which are the same as those of the divalent group. L H1 and Ar H2 and may be bonded directly or via a divalent group to form a ring, but it is preferable that they do not form a ring, as this facilitates the synthesis of the low molecular weight compound represented by formula (H-1). H1 and Ar H2 When Ar and Ar are bonded via a divalent group to form a ring, examples and preferred ranges of the divalent group include Ar H1 and Ar H2 and are bonded via a divalent group to form a ring, the examples and preferred ranges of which are the same as those of the divalent group.

[0197] Examples of the low molecular weight compound represented by formula (H-1) include compounds represented by the following formula:

[0198] [ka]

[0199] [ka]

[0200] [ka]

[0201] [ka]

[0202] [ka]

[0203] [ka]

[0204] (Low molecular weight compound represented by formula (ET-1)) nE1 is preferably an integer of 1 to 4, and more preferably 1 or 2.

[0205] Ar E1 The aromatic hydrocarbon group represented by the formula (I) is preferably a group obtained by removing one or more hydrogen atoms directly bonded to an atom constituting the ring from a monocyclic or bicyclic to hexacyclic aromatic hydrocarbon, more preferably a group obtained by removing one or more hydrogen atoms directly bonded to an atom constituting the ring from a monocyclic, bicyclic or tricyclic aromatic hydrocarbon, even more preferably a group obtained by removing one or more hydrogen atoms directly bonded to an atom constituting the ring from benzene, naphthalene, anthracene, phenanthrene, dihydrophenanthrene or fluorene, and particularly preferably a group obtained by removing one or more hydrogen atoms directly bonded to an atom constituting the ring from benzene, naphthalene, phenanthrene, dihydrophenanthrene or fluorene, and these groups may have a substituent.

[0206] Ar E1The heterocyclic group represented by the formula (I) is preferably a group in which one or more hydrogen atoms directly bonded to atoms constituting the ring have been removed from a monocyclic or bicyclic to hexacyclic heterocyclic compound, more preferably a group in which one or more hydrogen atoms directly bonded to atoms constituting the ring have been removed from a monocyclic, bicyclic or tricyclic heterocyclic compound, and even more preferably pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, carbazole, dibenzofuran, dibenzothiophene, phenoxazine, phenothiazine, 9 It is a group obtained by removing one or more hydrogen atoms directly bonded to an atom constituting the ring (preferably a carbon atom or a nitrogen atom, more preferably a carbon atom) from 5,10-dihydroacridine or 5,10-dihydrophenazine, and particularly preferably a group obtained by removing one or more hydrogen atoms directly bonded to an atom constituting the ring (preferably a carbon atom or a nitrogen atom, more preferably a carbon atom) from pyridine, diazabenzene, triazine, carbazole, dibenzofuran, dibenzothiophene, phenoxazine or phenothiazine, and these groups may have a substituent.

[0207] Ar E1 is preferably a group in which one or more hydrogen atoms directly bonded to atoms constituting the ring have been removed from benzene, naphthalene, fluorene, phenanthrene or carbazole, and this group is E1 may have a substituent other than the above.

[0208] Ar E1 may have R E1 Examples of the substituent other than the above 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, a cycloalkynyl group, a carboxyl group, and a group represented by formula (ES-3).

[0209] -O-(C n’ H 2n’ O) nx -C m’ H 2m’+1(ES-3) [In the formula, n', m', and nx each independently represent an integer of 1 or more.]

[0210] n' is preferably an integer of 1 to 10, more preferably an integer of 1 to 5, and even more preferably 2 or 3. m' is preferably an integer of 1 to 10, more preferably an integer of 1 to 5, and even more preferably 1 or 2. nx is preferably an integer of 1 to 10, more preferably an integer of 1 to 5, and even more preferably 3 or 4. nE3 is usually an integer of 0 to 10, preferably an integer of 0 to 8, and more preferably an integer of 0 to 2. aE1 is usually an integer of 1 to 10, preferably an integer of 1 to 5, and more preferably 1 or 2. bE1 is usually an integer of 0 to 10, preferably an integer of 0 to 4, and more preferably 0 or 1. mE1 is usually an integer of 1 to 5, preferably 1 or 2, and more preferably 1.

[0211] R E3 -OR E3’ In this case, the group represented by formula (ES-1) is a group represented by the following formula: -OR E3’ -{(Q E1 ) nE3 -Y E1 (M E1 ) aE1 (Z E1 ) bE1} mE1

[0212] R E3 As the alkyl group, a hydrocarbon group or a heterocyclic group is preferable, an aromatic hydrocarbon group or an aromatic heterocyclic group is more preferable, an aromatic hydrocarbon group is still more preferable, and a phenylene group is particularly preferable, and these groups may have a substituent. R E3Examples of the substituent that may be present include an alkyl group, a cycloalkyl group, an aryl group, a monovalent heterocyclic group, and a group represented by formula (ES-3), of which the group represented by formula (ES-3) is preferred, and these groups may further have a substituent.

[0213] Q E1 is preferably an alkylene group, an arylene group or an oxygen atom, more preferably an alkylene group or an oxygen atom, and these groups may have a substituent.

[0214] Y E1 As for -CO2 - , -SO2 - or -PO3 2- is preferred, -CO2 - is more preferred. M E1 Examples of alkali metal cations represented by the formula: + , Na + , K. + , Rb + , Cs + K + , Rb + or Cs + is preferred, and Cs + is more preferred. M E1 Examples of alkaline earth metal cations represented by the formula: 2+ , Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ Mg 2+ , Ca 2+ , Sr 2+ or Ba 2+ is preferred, and Ba 2+ is more preferred. M E1 When the ammonium cation represented by the formula (I) has a substituent, an example of the ammonium cation having a substituent is a tetramethylammonium cation. M E1As the cation, an alkali metal cation or an alkaline earth metal cation is preferred, and an alkali metal cation is more preferred. Z E1 As for F - , Cl - , Br - , I - , O.H. - , B(R E4 )4 - , R E4 SO3 - , R E4 COO - or NO3 - is preferred, and F - , Cl - , Br - , I - , O.H. - , R E4 SO3 - or R E4 COO - is preferred. E4 As the alkyl group, an alkyl group is preferred.

[0215] Examples of the group represented by formula (ES-1) include groups represented by the following formulas:

[0216] [ka]

[0217] [ka]

[0218] [ka]

[0219] [In the formula, M + Li + , Na + , K. + , Cs + or N(CH3)4 + Represents M +When there are multiple, they may be the same or different.

[0220] (Low molecular weight compound represented by formula (ET-2)) nE2 is usually an integer of 1 to 4, and preferably 1 or 2.

[0221] Ar E2 Examples and preferred ranges of the aromatic hydrocarbon group represented by Ar E1 The examples and preferred ranges of the aromatic hydrocarbon group are the same as those of the aromatic hydrocarbon group represented by the following formula: Ar E2 Examples and preferred ranges of the heterocyclic group represented by Ar E1 The examples and preferred ranges are the same as those of the divalent heterocyclic group represented by the following formula: Ar E2 Examples and preferred ranges of Ar E1 The examples and preferred ranges are the same as those of the above. Ar E2 may have R E2 The substituents other than Ar E1 may have R E1 The same applies to the substituents other than the above.

[0222] nE4 is usually an integer of 0 to 10, preferably an integer of 0 to 8, and more preferably an integer of 0 to 2. aE2 is usually an integer of 1 to 10, preferably an integer of 1 to 5, and more preferably 1 or 2. bE2 is usually an integer of 0 to 10, preferably an integer of 0 to 4, and more preferably 0 or 1. mE2 is usually an integer of 1 to 5, preferably 1 or 2, and more preferably 1.

[0223] R E5 -OR E5’ In this case, the group represented by formula (ES-2) is a group represented by the following formula: -OR E5’ -{(Q E1 ) nE3 -Y E1 (M E1 )aE1 (Z E1 ) bE1} mE1

[0224] R E5 As the group, a hydrocarbon group or a heterocyclic group is preferable, an aromatic hydrocarbon group or an aromatic heterocyclic group is more preferable, and an aromatic hydrocarbon group is even more preferable, and these groups may have a substituent.

[0225] R E5 Examples of the substituent that may be present include an alkyl group, a cycloalkyl group, an aryl group, a monovalent heterocyclic group, and a group represented by formula (ES-3), of which the group represented by formula (ES-3) is preferred, and these groups may further have a substituent.

[0226] Q E2 is preferably an alkylene group, an arylene group or an oxygen atom, more preferably an alkylene group or an oxygen atom, and these groups may have a substituent.

[0227] Y E2 As for -C + R E6 2, -N + R E6 3, -P + R E6 3 or S + R E6 2 is preferred, -N + R E6 3 is more preferred. E6 is preferably a hydrogen atom, an alkyl group or an aryl group, more preferably a hydrogen atom or an alkyl group, and these groups may have a substituent. M E2 As for F - , Cl - , Br - , I - , B(R E7 )4 - , R E7 SO3 - , R E7 COO - , BF4 - or SbF 6-is preferred, and Br - , I - , B(R E7 )4 - , R E7 COO - or SbF 6- is more preferable. E7 As the alkyl group, an alkyl group which may have a substituent is preferred. Z E2 Examples of alkali metal cations represented by the formula: + , Na + , K. + , Rb + , Cs + Li + , Na + or K + is preferred. Z E2 Examples of alkaline earth metal cations represented by the formula: 2+ , Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ Mg 2+ or Ca 2+ is preferred. Z E2 As the cation, alkali metal cations are preferred.

[0228] Examples of the group represented by formula (ES-2) include groups represented by the following formulas:

[0229] [ka]

[0230] [ka]

[0231] [where, X - is F - , Cl - , Br - , I - , B(C6H5)4 - , CH3COO- or CF3SO3 - represents X - When there are multiple, they may be the same or different.

[0232] Examples of the low molecular weight compound represented by formula (ET-1) and the low molecular weight compound represented by formula (ET-2) include the compounds shown below.

[0233] [ka]

[0234] [ka]

[0235] [ka]

[0236] [ka]

[0237] [ka]

[0238] [ka]

[0239] [ka]

[0240] (High molecular compound (ET)) The polymer compound (ET) is a polymer compound that includes at least one structural unit selected from the group consisting of the structural unit (ET-1), the structural unit (ET-2), the structural unit (X), and the structural unit (Y). In the polymer compound (ET), the structural unit (ET-1), the structural unit (ET-2), the structural unit represented by formula (X), and the structural unit represented by formula (Y) may each be contained in the polymer compound (ET) in a single type, or in two or more types.

[0241] · Building block (ET-1) The structural unit (ET-1) is preferably a structural unit having a group obtained by removing 1 to 5 hydrogen atoms from a low molecular weight compound represented by formula (ET-1), more preferably a structural unit having a group obtained by removing 1 to 3 hydrogen atoms from a low molecular weight compound represented by formula (ET-1), and even more preferably a structural unit having a group obtained by removing hydrogen atoms from a low molecular weight compound represented by formula (ET-1), because this allows for easy synthesis of the polymer compound (ET) and also reduces the driving voltage of the light-emitting device of the present disclosure. It is a structural unit having a group in which one or two hydrogen atoms have been removed, and particularly preferred is a structural unit having a group in which two hydrogen atoms have been removed from a low molecular weight compound represented by formula (ET-1).

[0242] The structural unit (ET-1) is a structural unit represented by formula (ET-1) because it further reduces the driving voltage of the light-emitting device of the present disclosure.

[0243] [ka]

[0244] [In the formula, nE1, Ar E1 and R E1 has the same meaning as above.]

[0245] · Building block (ET-2) The structural unit (ET-2) is preferably a structural unit having a group obtained by removing 1 to 5 hydrogen atoms from a low molecular weight compound represented by formula (ET-2), more preferably a structural unit having a group obtained by removing 1 to 3 hydrogen atoms from a low molecular weight compound represented by formula (ET-2), still more preferably a structural unit having a group obtained by removing 1 or 2 hydrogen atoms from a low molecular weight compound represented by formula (ET-2), and particularly preferably a structural unit having a group obtained by removing 2 hydrogen atoms from a low molecular weight compound represented by formula (ET-2).

[0246] The structural unit (ET-2) is a structural unit represented by formula (ET-2) because it further reduces the driving voltage of the light-emitting device of the present disclosure.

[0247] [ka]

[0248] [In the formula, nE2, Ar E2 and R E2 has the same meaning as above.]

[0249] Examples of the structural unit (ET-1) or the structural unit (ET-2) include structural units represented by formulae (ET-31) to (ET-38).

[0250] [ka]

[0251] [ka]

[0252] [ka]

[0253] 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, 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, 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, and these groups may have a substituent, because they result in a lower driving voltage for the light-emitting element of the present disclosure.

[0254] 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 heterocyclic compound, more preferably a group obtained by removing two hydrogen atoms directly bonded to atoms constituting the ring from a monocyclic, bicyclic or tricyclic heterocyclic compound, and even more preferably pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, carbazole, dibenzofuran, dibenzothiophene, phenoxazine, or phenothiazine, because the driving voltage of the light-emitting element of the present disclosure is lower. , 9,10-dihydroacridine, or 5,10-dihydrophenazine, by removing two hydrogen atoms directly bonded to atoms constituting the ring (preferably carbon atoms or nitrogen atoms, more preferably carbon atoms), and particularly preferred are groups 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, carbazole, dibenzofuran, dibenzothiophene, phenoxazine, or phenothiazine, and these groups may have a substituent.

[0255] 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:

[0256] Ar Y1 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 groups represented by the following formulae, and these groups may have a substituent.

[0257] [ka]

[0258] Ar Y1 is preferably an arylene group which may have a substituent, since this leads to a lower driving voltage of the light-emitting element of the present disclosure.

[0259] 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, a fluorine atom, or a bridging group, more preferably an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, a monovalent heterocyclic group, a substituted amino group, or a bridging group, even more preferably an alkyl group, a cycloalkyl group, an aryl group, a monovalent heterocyclic group, a substituted amino group, or a bridging group, and particularly preferably an alkyl group, a cycloalkyl group, an aryl group, or a bridging group, and these groups may further have a substituent. Ar Y1The aryl 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 has been removed from a monocyclic or bicyclic to hexacyclic aromatic hydrocarbon, 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, and even more preferably benzene, naphthalene, anthracene, or the like, because this reduces the driving voltage of the light-emitting element of the present disclosure. , phenanthrene, dihydrophenanthrene, or fluorene, by removing one hydrogen atom that is directly bonded to an atom that constitutes the ring, and particularly preferred are groups in which one hydrogen atom that is directly bonded to an atom that constitutes the ring is removed from benzene, phenanthrene, dihydrophenanthrene, or fluorene, and these groups may further have a substituent.

[0260] 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 has been removed from a monocyclic or bicyclic to hexacyclic heterocyclic compound, 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 heterocyclic compound, and even more preferably pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, carbazole, dibenzofuran, dibenzothiophene, and particularly preferred are groups obtained by removing one hydrogen atom directly bonded to an atom constituting the ring (preferably a carbon atom or a nitrogen atom) from pyridine, diazabenzene, triazine, carbazole, dibenzofuran, dibenzothiophene, phenoxazine, or phenothiazine, and these groups may further have a substituent.

[0261] 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.

[0262] 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, a fluorine atom, or a bridging group, more preferably an alkyl group, a cycloalkyl group, an aryl group, a monovalent heterocyclic group, a substituted amino group, or a bridging group, even more preferably an alkyl group, a cycloalkyl group, an aryl group, or a bridging group, and particularly preferably an alkyl group, a cycloalkyl group, or a bridging group, and these groups may further have a substituent, but preferably do not have a further substituent.

[0263] 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.

[0264] The structural unit represented by formula (Y) is preferably a structural unit represented by formula (Y-1) or formula (Y-2), since this lowers the driving voltage of the light-emitting device of the present disclosure.

[0265] [ka]

[0266] [In the formula, R Y1 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, a fluorine atom, or a bridging 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. 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 carbon 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 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, a fluorine atom, or a bridging 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. When there are multiple R Y2 may be the same or different and may be bonded to each other to form a ring together with the carbon atoms to which they are bonded.

[0267] R Y1 is preferably a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, a monovalent heterocyclic group, a substituted amino group, or a bridging group, more preferably a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a bridging group, and even more preferably a hydrogen atom, an alkyl group, or a bridging group, and these groups may have a substituent.

[0268] 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, a fluorine atom, or a crosslinking group, since this results in a lower driving voltage for the light-emitting element of the present disclosure; more preferably, an alkyl group, a cycloalkyl group, an aryl group, a monovalent heterocyclic group, a substituted amino group, or a crosslinking group; even more preferably, an alkyl group, a cycloalkyl group, an aryl group, or a crosslinking group; and particularly preferably, an alkyl group or a crosslinking group, and these groups may have a substituent.

[0269] R Y2 is preferably an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, a monovalent heterocyclic group, a substituted amino group, or a crosslinking group, since this results in a lower driving voltage for the light-emitting element of the present disclosure, more preferably an alkyl group, a cycloalkyl group, an aryl group, a monovalent heterocyclic group, or a crosslinking group, and even more preferably an alkyl group, a cycloalkyl group, an aryl group, or a crosslinking group, and these groups may have a substituent.

[0270] R Y1 and R Y2 Examples and preferred ranges of the aryl group, monovalent heterocyclic group and substituted amino group in 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. R Y1 and R Y2 Examples of the substituents that may be possessed by Ar and the preferred range thereof are as follows: Y1 Represented by The examples and preferred ranges of the substituents that the group may have are the same as those of the substituents that the group may have.

[0271] 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:

[0272] Examples of the constitutional unit represented by formula (Y) include constitutional units represented by the following formula:

[0273] [ka]

[0274] [ka]

[0275] [ka]

[0276] [ka]

[0277] [ka]

[0278] [ka]

[0279] [ka]

[0280] [ka]

[0281] [ka]

[0282] [ka]

[0283] [ka]

[0284] [ka]

[0285] [ka]

[0286] [ka]

[0287] [ka]

[0288] [ka]

[0289] 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 this reduces the driving voltage of the light-emitting element of the present disclosure.

[0290] 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, since the driving voltage of the light-emitting element of the present disclosure is lower. The group may have a substituent. 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.

[0291] Ar X1 , Ar X2 , Ar X3 and Ar X4 is preferably an arylene group which may have a substituent, since the driving voltage of the light-emitting element of the present disclosure is lowered. 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. Ar X2 and Ar X4 In 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.

[0292] Ar X1 ~Ar X4 and R X1 ~R X3 Examples of the substituents that the group represented by the formula (I) may have and their preferred ranges are: Y1The examples and preferred ranges of the substituents that may be possessed by the group represented by the formula:

[0293] Examples of the constitutional unit represented by formula (X) include constitutional units represented by the following formula:

[0294] [ka]

[0295] [ka]

[0296] [ka]

[0297] [ka]

[0298] [ka]

[0299] [ka]

[0300] [ka]

[0301] When the polymer compound (ET) contains the structural unit (ET-1), the content of the structural unit (ET-1) may be within a range that allows the polymer compound (ET) to function. When the polymer compound (ET) contains the structural unit (ET-1), the content of the structural unit (ET-1) relative to the total content of the structural units contained in the polymer compound (ET) is, for example, 0.1 to 100 mol %, and since this further reduces the driving voltage of the light-emitting device of the present disclosure, the content of the structural unit (ET-1) is preferably 1 to 100 mol %, more preferably 10 to 100 mol %, even more preferably 30 to 100 mol %, particularly preferably 50 to 100 mol %, even more preferably 70 to 100 mol %, and especially more preferably 90 to 100 mol %.

[0302] When the polymer compound (ET) contains the structural unit (ET-2), the content of the structural unit (ET-2) may be within a range that allows the polymer compound (ET) to function. When the polymer compound (ET) contains the structural unit (ET-2), the content of the structural unit (ET-2) relative to the total content of the structural units contained in the polymer compound (ET) is, for example, 0.1 to 100 mol %, and since this further reduces the driving voltage of the light-emitting device of the present disclosure, the content of the structural unit (ET-2) is preferably 1 to 100 mol %, more preferably 10 to 100 mol %, even more preferably 30 to 100 mol %, particularly preferably 50 to 100 mol %, even more preferably 70 to 100 mol %, and especially more preferably 90 to 100 mol %.

[0303] When the polymer compound (ET) contains the structural unit (Y), the content of the structural unit (Y) may be within a range that allows the polymer compound (ET) to function. When the polymer compound (ET) contains the structural unit (Y), the content of the structural unit (Y) relative to the total content of the structural units contained in the polymer compound (ET) is, for example, 0.1 to 100 mol %, and since this further reduces the driving voltage of the light-emitting device of the present disclosure, the content is preferably 1 to 100 mol %, more preferably 5 to 100 mol %, even more preferably 10 to 100 mol %, particularly preferably 20 to 100 mol %, even more preferably 30 to 100 mol %, and especially more preferably 40 to 100 mol %.

[0304] When the polymer compound (ET) contains the structural unit (X), the content of the structural unit (X) may be within a range that allows the polymer compound (ET) to function. When the polymer compound (ET) contains the structural unit (X), the content of the structural unit (X) relative to the total content of the structural units contained in the polymer compound (ET) is, for example, 0.01 to 100 mol %, and since this further reduces the driving voltage of the light-emitting device of the present disclosure, the content is preferably 0.05 to 99 mol %, more preferably 0.1 to 90 mol %, even more preferably 0.1 to 70 mol %, particularly preferably 0.2 to 50 mol %, even more preferably 0.5 to 30 mol %, and especially more preferably 1 to 50 mol %.

[0305] The total content of the structural units (ET-1), (ET-2), (Y), and (X) that may be contained in the polymer compound (ET) may be within a range that allows the polymer compound (ET) to function. The total content of the structural units (ET-1), (ET-2), (Y), and (X) that may be contained in the polymer compound (ET) is, for example, 0.1 to 100 mol% relative to the total content of the structural units contained in the polymer compound (ET). Since this results in a lower driving voltage for the light-emitting device of the present disclosure, the total content is preferably 1 to 100 mol%, more preferably 10 to 100 mol%, even more preferably 30 to 100 mol%, particularly preferably 50 to 100 mol%, even more preferably 70 to 100 mol%, and especially more preferably 90 to 100 mol%.

[0306] Examples of the polymer compound (ET) include polymer compounds EP-1 to EP-16 shown in Table 4. Here, "other" refers to structural units other than the structural unit (ET-1), the structural unit (ET-2), the structural unit (Y), and the structural unit (X).

[0307] [Table 4]

[0308] The polymer compound (ET) may be any of a block copolymer, a random copolymer, an alternating copolymer, a graft copolymer, or other forms, but is preferably a copolymer obtained by copolymerizing a plurality of raw material monomers. The number average molecular weight of the polymer compound (ET) in terms of polystyrene is preferably 5×10 3 ~ 1×10 6 and more preferably 1×10 4 ~5×10 5 and more preferably 1.5 × 10 4 ~1×10 5 is.

[0309] [Method for producing polymer compound (ET)] The polymer compound (ET) can be synthesized according to the methods described in, for example, JP-A Nos. 2009-239279, 2012-033845, 2012-216821, 2012-216822, and 2012-216815.

[0310] <First Electron Transport Layer> The first electron transport layer may contain only one type of compound (ET), or may contain two or more types of compound (ET). The content of the compound (ET) in the first electron transport layer is not particularly limited, and may be within a range in which the function of the first electron transport layer is exhibited. The content of the compound (ET) in the first electron transport layer may be, for example, 1 to 100 mass% based on the total amount of the first electron transport 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 further reduces the driving voltage of the light-emitting device of the present disclosure.

[0311] The first electron transport layer is preferably a layer containing at least one of a low molecular weight compound represented by formula (ET-1), a low molecular weight compound represented by formula (ET-2), and a polymer compound (ET), because this reduces the driving voltage of the light-emitting device of the present disclosure; more preferably a layer containing a polymer compound (ET); even more preferably a layer containing a polymer compound having at least one structural unit selected from the group consisting of structural units (X) and (Y); and particularly preferably a layer containing a polymer compound having at least one structural unit selected from the group consisting of structural units (X) and (Y), but not having structural units (ET-1) and (ET-2).

[0312] [First composition] The first electron transport layer may be a layer containing a composition (hereinafter also referred to as "first composition") containing the compound (ET) and at least one selected from the group consisting of an electron transport material, an electron injection material, and an antioxidant. In the first electron transport layer, the electron transport material and the electron injection material are different from the compound (ET). The first composition may contain one kind of compound (ET), one kind of electron transport material, one kind of electron injection material, and one kind of antioxidant, or may contain two or more kinds of them. Examples and preferred ranges of the electron transport material, electron injection material, and antioxidant contained in the first composition are the same as the examples and preferred ranges of the electron transport material, electron injection material, and antioxidant contained in the composition of the light-emitting layer (B), respectively.

[0313] The total content of the compound (ET), electron transport material, electron injection material, and antioxidant in the first composition may be within a range that allows the first composition to function. The total content of the compound (ET), electron transport material, electron injection material, and antioxidant in the first composition may be, for example, 1 to 100 mass%, 10 to 100 mass%, or 30 to 100 mass%, more preferably 50 to 100 mass%, 70 to 100 mass%, or 90 to 100 mass%, based on the total amount of the first composition. In the first composition, the content of the electron transport material and the content of the electron injection material are each usually 1 to 10,000 parts by mass when the content of the compound (ET) is taken as 100 parts by mass. In the first composition, the content of the antioxidant is usually 1 to 10,000 parts by mass when the content of the compound (ET) is taken as 100 parts by mass. In this case, the amount is usually 0.00001 to 10 parts by mass.

[0314] [First Ink] The first electron transport layer can be formed using, for example, a composition containing the compound (ET) and a solvent (hereinafter also referred to as "first ink"). The first ink may contain one kind of compound (ET) and one kind of solvent, or two or more kinds of compounds (ET) and solvents. The first ink can be suitably used in the wet method described in the section on the ink for the light-emitting layer (B). The preferred range of the viscosity of the first ink is the same as the preferred range of the viscosity of the ink for the light-emitting layer (B).

[0315] Examples and preferred ranges of the solvent contained in the first ink are the same as the examples and preferred ranges of the solvent contained in the ink for the light-emitting layer (B). The solvent contained in the first ink can be, for example, water, alcohol, ether, ester, nitrile compound, nitro compound, fluorinated alcohol, thiol, sulfide, sulfoxide, thioketone, amide, and / or carboxylic acid, since it allows the first electron transport layer to be laminated on a layer (e.g., the light-emitting layer (B)) by utilizing the difference in solubility. Specific examples of such solvents include methanol, ethanol, 2-propanol, 1-butanol, tert-butyl alcohol, acetonitrile, 1,2-ethanediol, N,N-dimethylformamide, dimethyl sulfoxide, acetic acid, nitromethane, propylene carbonate, pyridine, carbon disulfide, and mixtures of these solvents. When a mixed solvent is used, it may be a mixture of one or more solvents selected from water, alcohol, ether, ester, nitrile compound, nitro compound, fluorinated alcohol, thiol, sulfide, sulfoxide, thioketone, amide, and carboxylic acid with one or more solvents selected from chlorinated solvents, aromatic hydrocarbon solvents, aliphatic hydrocarbon solvents, and ketone solvents. In the first ink, the content of the solvent is usually 1,000 to 10,000,000 parts by mass, assuming that the content of compound (ET) is 100 parts by mass.

[0316] The first ink may further contain at least one selected from the group consisting of an electron transport material, an electron injection material, and an antioxidant. The first ink may contain one kind of electron transport material, one kind of electron injection material, and one kind of antioxidant, or two or more kinds of them. Examples and preferred ranges of the electron transport material, electron injection material, and antioxidant that the first ink may further contain are the same as the examples and preferred ranges of the electron transport material, electron injection material, and antioxidant contained in the first composition, respectively. The content of the electron transport material and the electron injection material, which may be further contained in the first ink, is usually 1 to 10,000 parts by mass, respectively, relative to 100 parts by mass of the compound (ET). The content of the antioxidant, which may be further contained in the first ink, is usually 0.00001 to 10 parts by mass, relative to 100 parts by mass of the compound (ET).

[0317] <Second Electron Transport Layer> The second electron transport layer may contain only one type of compound (ET), or may contain two or more types of compound (ET). The content of the compound (ET) in the second electron transport layer is not particularly limited, and may be within a range in which the function of the second electron transport layer is exhibited. The content of the compound (ET) in the second electron transport layer may be, for example, 1 to 100 mass% based on the total amount of the second electron transport 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 reduces the driving voltage of the light-emitting device of the present disclosure. do.

[0318] The second electron transport layer is preferably a layer containing at least one of a low molecular weight compound represented by formula (ET-1), a low molecular weight compound represented by formula (ET-2), and a polymer compound (ET), because this lowers the driving voltage of the light-emitting element of the present disclosure; more preferably a layer containing at least one of a low molecular weight compound represented by formula (ET-1), a low molecular weight compound represented by formula (ET-2), a polymer compound having the structural unit (ET-1), and a polymer compound having the structural unit (ET-2); and even more preferably a layer containing a polymer compound having the structural unit (ET-1).

[0319] [Second Composition] The second electron transport layer may be a layer containing a composition (hereinafter also referred to as "second composition") containing compound (ET) and at least one selected from the group consisting of an electron transport material, an electron injection material, and an antioxidant. In the second electron transport layer, the electron transport material and the electron injection material are different from compound (ET). The second composition may contain one kind of compound (ET), one kind of electron transport material, one kind of electron injection material, and one kind of antioxidant, or may contain two or more kinds of them. Examples and preferred ranges of the electron transport material, electron injection material, and antioxidant contained in the second composition are the same as the examples and preferred ranges of the electron transport material, electron injection material, and antioxidant contained in the composition of the light-emitting layer (B), respectively.

[0320] The total content of the compound (ET), electron transport material, electron injection material, and antioxidant in the second composition may be within a range that allows the second composition to function properly. The total content of the compound (ET), electron transport material, electron injection material, and antioxidant in the second composition may be, for example, 1 to 100 mass%, 10 to 100 mass%, or 30 to 100 mass%, 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 the electron transport material and the content of the electron injection material are each usually 1 to 10,000 parts by mass, relative to 100 parts by mass of the compound (ET). In the second composition, the content of the antioxidant is usually 0.00001 to 10 parts by mass, relative to 100 parts by mass of the compound (ET).

[0321] [Second Ink] The second electron transport layer can be formed using, for example, a composition containing the compound (ET) and a solvent (hereinafter also referred to as "second ink"). The second ink may contain one kind of compound (ET) and one kind of solvent, or two or more kinds of compounds (ET) and solvents. The second ink can be suitably used in the wet method described in the section on the ink for the light-emitting layer (B). The preferred range of the viscosity of the second ink is the same as the preferred range of the viscosity of the ink for the light-emitting layer (B).

[0322] Examples and preferred ranges of the solvent contained in the second ink are the same as the examples and preferred ranges of the solvent contained in the ink for the light-emitting layer (B). The solvent contained in the second ink can be, for example, water, alcohol, ether, ester, nitrile compound, nitro compound, fluorinated alcohol, thiol, sulfide, sulfoxide, thioketone, amide, and / or carboxylic acid, since it can laminate a second electron transport layer on a layer (e.g., a first electron transport layer) by utilizing the difference in solubility. Specific examples of the solvent include methanol, ethanol, 2-propanol, and 1-butanol. Examples of suitable solvents include tert-butyl alcohol, acetonitrile, 1,2-ethanediol, N,N-dimethylformamide, dimethyl sulfoxide, acetic acid, nitromethane, propylene carbonate, pyridine, carbon disulfide, and mixed solvents of these solvents. When a mixed solvent is used, it may be a mixed solvent of one or more solvents selected from water, alcohols, ethers, esters, nitrile compounds, nitro compounds, fluorinated alcohols, thiols, sulfides, sulfoxides, thioketones, amides, and carboxylic acids, and one or more solvents selected from chlorine-based solvents, aromatic hydrocarbon-based solvents, aliphatic hydrocarbon-based solvents, and ketone-based solvents. In the second ink, the content of the solvent is usually 1,000 to 10,000,000 parts by mass, assuming that the content of the compound (ET) is 100 parts by mass.

[0323] The second ink may further contain at least one selected from the group consisting of an electron transport material, an electron injection material, and an antioxidant. The second ink may contain one kind of electron transport material, one kind of electron injection material, and one kind of antioxidant, or two or more kinds of them. Examples and preferred ranges of the electron transport material, electron injection material, and antioxidant that the second ink may further contain are the same as the examples and preferred ranges of the electron transport material, electron injection material, and antioxidant contained in the second composition, respectively. The content of the electron transport material, electron injection material, and antioxidant that may be further contained in the second ink is usually 1 to 10,000 parts by mass, based on 100 parts by mass of the compound (ET). The content of the antioxidant that may be further contained in the second ink is usually 0.00001 to 10 parts by mass, based on 100 parts by mass of the compound (ET).

[0324] <Light-emitting element> The light-emitting element of the present disclosure is a light-emitting element having an anode, a cathode, a light-emitting layer (B) provided between the anode and the cathode, a first electron transport layer provided between the light-emitting layer (B) and the cathode, and a second electron transport layer provided between the first electron transport layer and the cathode. The light-emitting device of this embodiment may further include layers other than the anode, the cathode, the light-emitting layer (B), the first electron transport layer, and the second electron transport layer.

[0325] In the light-emitting element of the present disclosure, two or more layers of each of the anode, hole injection layer, hole transport layer, light-emitting layer (i.e., light-emitting layer (B) and a light-emitting layer other than light-emitting layer (B)), 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, but are preferably different. Furthermore, adjacent layers are preferably formed from different materials.

[0326] The light-emitting device of the present disclosure has a low driving voltage. The reason for the above effect is presumed to be as follows, but is not limited to this.

[0327] The light-emitting element of the present disclosure has, in addition to the light-emitting layer (B), a first electron transport layer and / or a second electron transport layer containing a specific polymer compound, and thereby the light-emitting properties, charge transport properties and / or charge injection properties of the light-emitting layer (B), the first electron transport layer and the second electron transport layer can be improved or adjusted. Furthermore, by providing the first electron transport layer and / or the second electron transport layer containing a specific polymer compound, the film quality of the first electron transport layer and the second electron transport layer is improved, and for example, the charge injection characteristics from the second electron transport layer to the first electron transport layer, the charge injection characteristics from the first electron transport layer to the light-emitting layer (B), and / or the charge injection characteristics from the cathode to the second electron transport layer are improved or adjusted, which is presumably why the driving voltage of the light-emitting device is reduced.

[0328] In the light-emitting device of the present disclosure, it is preferable that the light-emitting layer (B) and the first electron transport layer are adjacent to each other, since this leads to a lower driving voltage for the light-emitting device of the present disclosure. In addition, in the light-emitting device of the present disclosure, the first electron transport layer and the second electron transport layer are preferably adjacent to each other, since this reduces the driving voltage of the light-emitting device of the present disclosure.

[0329] In the light-emitting device of the present disclosure, the light-emitting layer (B) is also referred to as the "first light-emitting layer" hereinafter.

[0330] 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 light-emitting layer (B), as this will result in a lower driving voltage for the light-emitting device of the present disclosure. Since the driving voltage of the light-emitting element of the present disclosure is lower, it is preferable to further include at least one layer of an electron injection layer and an electron transport layer between the second electron transport layer and the cathode, and it is more preferable to include an electron injection layer.

[0331] Specific layer configurations of the light-emitting device of the present disclosure include, for example, layer configurations represented by the following (D1) to (D10): The light-emitting device of the present disclosure usually has a substrate, but may have the anode layered on the substrate, or the cathode layered on the substrate.

[0332] (D1) Anode / first light-emitting layer (light-emitting layer (B)) / first electron transport layer / second electron transport layer / cathode (D2) Anode / first light-emitting layer (light-emitting layer (B)) / first electron transport layer / second electron transport layer / electron injection layer / cathode (D3) Anode / hole injection layer / first light-emitting layer (light-emitting layer (B)) / first electron transport layer / second electron transport layer / electron injection layer / cathode (D4) Anode / hole transport layer / first light-emitting layer (light-emitting layer (B)) / first electron transport layer / second electron transport layer / electron injection layer / cathode (D5) Anode / hole injection layer / hole transport layer / first light-emitting layer (light-emitting layer (B)) / first electron transport layer / second electron transport layer / electron injection layer / cathode (D6) Anode / hole injection layer / hole transport layer / second light-emitting layer / first light-emitting layer (light-emitting layer (B)) / first electron transport layer / second electron transport layer / electron injection layer / cathode (D7) Anode / hole injection layer / hole transport layer / first emitting layer (emitting layer (B)) / second emitting layer / first electron transport layer / second electron transport layer / electron injection layer / cathode (D8) Anode / hole injection layer / hole transport layer / first light-emitting layer (light-emitting layer (B)) / electron transport layer (third electron transport layer) / first electron transport layer / second electron transport layer / electron injection layer / cathode (D9) Anode / hole injection layer / hole transport layer / first light-emitting layer (light-emitting layer (B)) / first electron transport layer / electron transport layer (third electron transport layer) / second electron transport layer / electron injection layer / cathode (D10) Anode / hole injection layer / hole transport layer / first light-emitting layer (light-emitting layer (B)) / first electron transport layer / second electron transport layer / electron transport layer (third electron transport layer) / electron injection layer / cathode

[0333] In the above (D1) to (D10), " / " means that the layers before and after it are adjacent to each other. For example, "first light-emitting layer (light-emitting layer (B)) / first electron-transporting layer" means that the first light-emitting layer (light-emitting layer (B)) and the first electron-transporting layer are adjacent to each other.

[0334] In the light-emitting element of the present disclosure, the thickness of each of the anode, hole injection layer, hole transport layer, first electron transport layer, second electron transport layer, light-emitting layer (B), electron transport layer (i.e., an electron transport layer different from the first electron transport layer and the second electron transport layer, hereinafter also referred to as "third 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.

[0335] In the light-emitting device of the present disclosure, the order, number, and thickness of the layers to be stacked are determined based on the luminance life of the light-emitting device. The amount can be adjusted taking into consideration the following factors.

[0336] [First light-emitting layer] The first light-emitting layer is the light-emitting layer (B).

[0337] [Second light-emitting layer] 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 above-mentioned compound (B), the above-mentioned compound (A), and the light-emitting material that may be contained in the composition of the above-mentioned light-emitting layer (B). The second light-emitting layer may contain one type of light-emitting material alone, or two or more types of light-emitting materials.

[0338] [Hole transport layer] 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 composition of the light-emitting layer (B). The hole transport layer may contain one type of hole transport material alone, or two or more types of hole transport materials. The hole transport layer preferably does not contain a low-molecular-weight compound (B), and more preferably does not contain a low-molecular-weight compound (B) or a high-molecular-weight compound (B).

[0339] [Third Electron Transport Layer] The third electron transport layer is a layer containing an electron transport material. Examples of the electron transport material contained in the third electron transport layer include the aforementioned compound (ET) and the electron transport material that may be contained in the composition of the aforementioned light-emitting layer (B). The third electron transport layer may contain one type of electron transport material alone, or two or more types of electron transport materials.

[0340] [Hole injection layer] 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 materials that may be contained in the composition of the light-emitting layer (B) described above. The hole injection layer may contain one type of hole injection material alone, or two or more types of hole injection materials. The hole injection layer preferably does not contain a low-molecular-weight compound (B), and more preferably does not contain a low-molecular-weight compound (B) or a high-molecular-weight compound (B).

[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 materials that may be contained in the composition of the light-emitting layer (B). 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. 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. In the light-emitting device of the present disclosure, 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.

[0344] Examples of methods for forming the anode and cathode include vacuum deposition, sputtering, ion plating, plating, and lamination.

[0345] [Method of manufacturing light-emitting element] In the method for manufacturing a light-emitting element according to the present disclosure, examples of methods for forming the light-emitting layer (B), the first electron transport layer, the second electron transport layer, and layers other than the light-emitting layer (B), the first electron transport layer, and the second electron transport layer include, when a low-molecular-weight compound is used, dry methods such as vacuum deposition and wet methods described in the section on the ink for the light-emitting layer (B), and when a high-molecular-weight compound is used, wet methods described in the section on the ink for the light-emitting layer (B). In the method for manufacturing the light-emitting element of the present embodiment, the light-emitting layer (B), the first electron transport layer, the second electron transport layer, and layers other than the light-emitting layer (B), the first electron transport layer, and the second electron transport layer may be formed using the various inks described above and inks containing the various materials and solvents described above by the wet method described in the section on the ink for the light-emitting layer (B), or by a dry method such as a vacuum deposition method.

[0346] Methods for forming the light-emitting layer (B), the first electron transport layer, and the second electron transport layer include, for example, dry methods and wet methods, with wet methods being preferred because they facilitate the production of the light-emitting device of the present disclosure. Examples of dry methods for forming the light-emitting layer (B), the first electron transport layer, and the second electron transport layer include vacuum deposition. Examples of wet methods for forming the light-emitting layer (B), the first electron transport layer, and the second electron transport layer include the wet methods described in the section on the ink for the light-emitting layer (B). When the light-emitting layer (B) is formed by a wet method, it is preferable to use an ink for the light-emitting layer (B) because this facilitates the manufacture of the light-emitting device of the embodiment. That is, it is preferable to form the light-emitting layer (B) by a wet method using an ink for the light-emitting layer (B). When the first electron transport layer is formed by a wet process, it is preferable to use the first ink because this facilitates the manufacture of the light-emitting device of the embodiment. That is, it is preferable to form the first electron transport layer by a wet process using the first ink. When the second electron transport layer is formed by a wet process, it is preferable to use the second ink because this facilitates the manufacture of the light-emitting device of the embodiment. That is, it is preferable to form the second electron transport layer by a wet process using the second ink.

[0347] In the method for producing a light-emitting element of the present disclosure, a layer containing a crosslinked product of a compound having a crosslinking group (e.g., the light-emitting layer (B), the first electron transport layer, and the second electron transport layer) can be formed, for example, by forming a layer containing a compound having a crosslinking group, and then heating or irradiating the layer with light (preferably heating) to crosslink the compound having a crosslinking group contained in the layer. When a compound having a crosslinking group is contained in a layer in a crosslinked state (a crosslinked product of a compound having a crosslinking group), the layer is substantially insolubilized in a solvent. Therefore, a layer containing a crosslinked product of a compound having a crosslinking group can be suitably used for laminating layers in the production of a light-emitting element of the present disclosure.

[0348] From the above viewpoints, in the method for producing a light-emitting element according to the present disclosure, the step of forming the light-emitting layer (B), the first electron transport layer, or the second electron transport layer using a compound having a crosslinking group preferably includes the steps of forming a layer containing a compound having a crosslinking group, and then crosslinking the compound having a crosslinking group contained in the layer to form the light-emitting layer (B), the first electron transport layer, or the second electron transport layer containing a crosslinked product of the compound having a crosslinking group. In the step of forming the light-emitting layer (B), the first electron transport layer, or the second electron transport layer using a compound having a crosslinking group, the method of crosslinking the compound having a crosslinking group is preferably a method of crosslinking by heating or light irradiation, since this facilitates production of the light-emitting element of the embodiment, and more preferably a method of crosslinking by heating.

[0349] 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, more preferably 1 to 120 minutes, and even more preferably 10 to 60 minutes. The type of light used for the light irradiation is, for example, ultraviolet light, near ultraviolet light, or visible light.

[0350] Examples of the process of forming the light-emitting layer (B), the first electron transport layer, or the second electron transport layer using a compound having a crosslinking group include a method of forming a layer by a wet method using the ink for the light-emitting layer (B), the first ink, or the second ink, and then crosslinking the compound having a crosslinking group contained in the layer to form the light-emitting layer (B), the first electron transport layer, or the second electron transport layer; and a method of forming a layer by a dry method or wet method (preferably a wet method) using a compound having a crosslinking group, and then crosslinking the compound having a crosslinking group contained in the layer to form the light-emitting layer (B), the first electron transport layer, or the second electron transport layer.

[0351] Methods for analyzing components contained in the light-emitting layer (B), the first electron transport layer, the second electron transport layer, or layers other than the light-emitting layer (B), the first electron transport layer, and the second electron transport layer 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. By performing solid-liquid extraction using an organic solvent such as toluene, xylene, chloroform, or tetrahydrofuran on the light-emitting layer (B), the first electron transport layer, the second electron transport layer, or a layer other than the light-emitting layer (B), the first electron transport layer, and the second electron transport layer, it is possible to separate the layer 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.

[0352] The light-emitting element of the present disclosure 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-side substrate having a cathode or each layer stacked on the cathode.

[0353] In the production of the light-emitting device of the present disclosure, when the material used to form the hole injection layer, the material used to form the light-emitting layer, the material used to form the hole transport layer, the material used to form the electron transport layer, and the material used to form the electron injection layer are each soluble in a solvent used in forming the hole injection layer, the light-emitting layer, the hole transport layer, the electron transport layer, and the layer adjacent to the electron injection layer, the material is soluble in the solvent. It is preferable to avoid dissolution of the material. Methods for avoiding dissolution of the material include i) a method using a material having a crosslinking group, and ii) a method of providing a difference in solubility in a solvent between adjacent layers. As the method i), for example, a layer (e.g., a hole transport layer) is formed using a material having a crosslinking group, and then the crosslinking group is crosslinked to insolubilize the layer, and a layer different from the layer (e.g., a light-emitting layer) can be laminated on the layer. As the method ii), for example, a layer (e.g., a light-emitting layer) is formed, and then a layer different from the layer (e.g., an electron transport layer) can be laminated on the layer by using an ink containing a solvent with low solubility in the layer.

[0354] [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]

[0355] Hereinafter, one embodiment of the present disclosure will be described in more detail with reference to examples, but the present disclosure is not limited to these examples.

[0356] In the examples, the polystyrene-equivalent number average molecular weight (Mn) and polystyrene-equivalent weight average molecular weight (Mw) of the polymer compound were determined by size exclusion chromatography (SEC) using tetrahydrofuran as the mobile phase. The SEC measurement conditions were as follows: The polymer compound to be measured was dissolved in tetrahydrofuran at a concentration of approximately 0.05% by mass, and 10 μL of the solution was injected into the SEC device. 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).

[0357] NMR was measured by the following method. 5 to 10 mg of a measurement sample was dissolved in approximately 0.5 mL of deuterated chloroform (CDCl3), deuterated tetrahydrofuran, deuterated dimethyl sulfoxide, deuterated acetone, deuterated N,N-dimethylformamide, deuterated toluene, deuterated methanol, deuterated ethanol, deuterated 2-propanol, or deuterated methylene chloride, and the solution was measured using an NMR apparatus (manufactured by Agilent, trade name: INOVA300 or MERCURY 400VX).

[0358] ΔE of the compound ST The calculation of the ΔE value of the compound was carried out by optimizing the ground state of the compound using the density functional theory at the B3LYP level. At that time, 6-31G* was used as the basis function. Then, using the obtained optimized structure, the ΔE value of the compound was calculated using the time-dependent density functional theory at the B3LYP level. ST The calculation was performed using Gaussian09 as a quantum chemistry calculation program.

[0359] The maximum peak wavelength of the emission spectrum of the compound at room temperature was measured at room temperature using a spectrophotometer (JASCO Corporation, FP-6500). -4 The xylene solution dissolved at a concentration of 100% by mass was used as the sample. Ultraviolet (UV) light with a wavelength of 325 nm was used as the excitation light.

[0360] <Synthesis and Acquisition of Compound H1, Compound B1, Compound MC1, and Compound HT2> Compound H1, compound B1, and compound HT2 were manufactured by Luminescence Technology. Compound MC1 was synthesized according to the method described in JP 2013-147551 A.

[0361] [ka]

[0362] ΔE of compound B1 STThe maximum peak wavelength of the emission spectrum of Compound B1 at room temperature was 452 nm. The half-value width of the maximum peak of the emission spectrum of Compound B1 at room temperature was 22 nm.

[0363] <Synthesis of Compounds M1 to M11> Compound M1 was synthesized according to the method described in WO 2015 / 145871. Compound M2 was synthesized according to the method described in WO 2013 / 146806. Compound M3 was synthesized according to the method described in WO 2005 / 049546. Compound M4 was synthesized according to the method described in JP-A-2010-189630. Compound M5 was synthesized according to the method described in WO 2013 / 191088. Compound M6 was synthesized according to the method described in WO 2015 / 145871. Compound M7 was synthesized according to the method described in JP 2015-086215 A. Compound M8 was synthesized according to the method described in WO 2002 / 045184. Compound M9 was synthesized according to the method described in WO 2012 / 086671. Compound M10 was synthesized according to the method described in WO 2009 / 131255. Compound M11 was synthesized according to the method described in JP-A-2004-143419.

[0364] [ka]

[0365] <Synthesis of polymer compound HT1> The polymer compound HT1 was synthesized using compounds M1, M2, and M3 according to the method described in WO 2015 / 145871. The Mn of the polymer compound HT1 was 2.3 × 10 4 and Mw is 1.2 × 10 5It was. Polymer compound HT1 is a copolymer composed of structural units derived from compound M1, structural units derived from compound M2, and structural units derived from compound M3 in a molar ratio of 45:5:50, according to the theoretical value calculated from the amounts of the raw materials charged.

[0366] <Synthesis of polymer compound ET1> (Synthesis of polymer compound ET1a) Polymer compound ET1a was synthesized according to the method described in JP-A-2012-33845 using compound ET1-1 synthesized according to the method described in JP-A-2012-33845 and compound ET1-2 synthesized according to the method described in JP-A-2012-33845.

[0367] [ka]

[0368] The Mn of the polymer compound ET1a is 5.2 × 10 4 It was.

[0369] The polymer compound ET1a is a copolymer composed of structural units derived from compound ET1-1 and structural units derived from compound ET1-2 in a molar ratio of 50:50, according to the theoretical value calculated from the amounts of the raw materials charged.

[0370] (Synthesis of polymer compound ET1) After creating an inert gas atmosphere in the reaction vessel, polymer compound ET1a (200 mg), tetrahydrofuran (20 mL), and ethanol (20 mL) were added and heated to 55°C. Cesium hydroxide (200 mg) dissolved in water (2 mL) was then added thereto, and the mixture was stirred at 55°C for 6 hours. After cooling to room temperature, the mixture was concentrated under reduced pressure to obtain a solid. The obtained solid was washed with water and then dried under reduced pressure to obtain polymer compound ET1 (150 mg, pale yellow solid). The NMR spectrum of the obtained polymer compound ET1 confirmed that the signals derived from the ethyl group of the ethyl ester moiety of polymer compound ET1a had completely disappeared.

[0371] [ka]

[0372] <Synthesis of polymer compound ET2> The polymer compound ET2 was synthesized using compounds M4, M5, and M6 according to the method described in WO 2015 / 008851. The Mn of the polymer compound ET2 is 8.5 × 10 4 and Mw is 2.2 × 10 5 It was. Polymer compound ET2 is a copolymer composed of structural units derived from compound M4, structural units derived from compound M5, and structural units derived from compound M6 in a molar ratio of 50:26:24, according to the theoretical value calculated from the amounts of the raw materials charged.

[0373] <Synthesis of polymer compound ET3> The polymer compound ET3 was synthesized using the compound M4 and the compound M5 according to the method described in WO 2013 / 191088. The Mn of the polymer compound ET3 is 9.7×10 4 and Mw is 2.9 × 10 5 It was. Polymer compound ET3 is a copolymer composed of structural units derived from compound M4 and structural units derived from compound M5 in a molar ratio of 50:50, according to the theoretical value calculated from the amounts of the raw materials charged.

[0374] <Synthesis of polymer compound ET4> The polymer compound ET4 was synthesized using the compound M4 and the compound M3 according to the method described in WO 2019 / 004247. The Mn of the polymer compound ET4 is 4.5×10 4 and Mw is 1.5×10 5 It was. Polymer compound ET4 is a copolymer composed of structural units derived from compound M4 and structural units derived from compound M3 in a molar ratio of 50:50, according to the theoretical value calculated from the amounts of the raw materials charged.

[0375] <Synthesis of polymer compound ET5> The polymer compound ET5 was synthesized using compounds M7, M8, M9, M10, and M11 according to the method described in WO 2017 / 061332. The Mn of the polymer compound ET5 is 1.4 × 10 5 and Mw is 4.1 × 10 5 It was. Polymer compound ET5 is a copolymer composed of structural units derived from compound M7, structural units derived from compound M8, structural units derived from compound M9, structural units derived from compound M10, and structural units derived from compound M11 in a molar ratio of 50:30:10:5:5, according to the theoretical value calculated from the amounts of the raw materials charged.

[0376] Example D1 Fabrication and Evaluation of Light-Emitting Device D1 (Formation of anode and hole injection layer) An anode was formed by sputtering a 45-nm thick ITO film on a glass substrate. A 35-nm thick film of hole injection material ND-3202 (manufactured by Nissan Chemical Co., Ltd.) was spin-coated onto the anode to form a coating. The substrate with the coating was heated on a hot plate in an air atmosphere at 50°C for 3 minutes and then at 230°C for 15 minutes to form a hole injection layer.

[0377] (Formation of hole transport layer) Polymer compound HT1 was dissolved in xylene. The resulting xylene solution was used to form a 20 nm thick film on the hole injection layer by spin coating, and the film was heated at 180°C for 60 minutes on a hot plate in a nitrogen gas atmosphere to form a hole transport layer. This heating caused the polymer compound HT1 to become crosslinked.

[0378] (Formation of light-emitting layer (B)) Compound H1, Compound MC1, and Compound B1 (Compound H1 / Compound MC1 / Compound B1 = 73% by mass / 25% by mass / 2% by mass) were dissolved in chlorobenzene. The resulting toluene solution was used to form a film with a thickness of 60 nm on the hole transport layer by spin coating, and the film was heated at 130°C for 10 minutes in a nitrogen gas atmosphere to form an emitting layer (B).

[0379] (Formation of the first electron transport layer) The polymer compound ET2 was dissolved in xylene, and the resulting xylene was used to form a film with a thickness of 10 nm on the light-emitting layer (B) by spin coating. The film was then heated at 130°C for 10 minutes in a nitrogen gas atmosphere to form a first electron transport layer.

[0380] (Formation of the second electron transport layer) The polymer compound ET1 was dissolved in 2,2,3,3,4,4,5,5-octafluoro-1-pentanol, and the resulting 2,2,3,3,4,4,5,5-octafluoro-1-pentanol solution was spin-coated onto the first electron transport layer to form a 10 nm thick film. The film was then heated at 130°C for 10 minutes in a nitrogen gas atmosphere to form a second electron transport layer.

[0381] (Cathode formation) The substrate on which the second electron transport layer was formed was placed in a deposition machine. -4 After reducing the pressure to below 1 Pa, sodium fluoride and aluminum were sequentially vapor-deposited on the second electron transport layer to form an electron injection layer with a thickness of approximately 4 nm and a cathode with a thickness of approximately 80 nm. The substrate on which the cathode was formed was then sealed with a glass substrate to produce light-emitting device D1.

[0382] (Evaluation of light-emitting elements) EL light emission was observed by applying a voltage to the light-emitting element D1. 2 The driving voltage was measured.

[0383] Examples D2 to D4 Fabrication and evaluation of light-emitting elements D2 to D4 Light-emitting devices D2 to D4 were fabricated in the same manner as in Example D1 (formation of the first electron transport layer), except that the materials listed in Table 5 were used instead of the "polymer compound ET2" in Example D1. EL emission was observed by applying a voltage to the light-emitting devices D2 to D4. 2 The driving voltage was measured.

[0384] <Comparative Example CD1> Fabrication and Evaluation of Light-Emitting Device CD1 A light-emitting device CD1 was fabricated in the same manner as in Example D1, except that (the formation of the first electron transport layer) in Example D1 was not performed, and (the formation of the second electron transport layer) was performed as described below (Formation of the second electron transport layer CD1). EL emission was observed by applying a voltage to the light-emitting device CD1. 2 The driving voltage was measured.

[0385] (Formation of second electron transport layer CD1) The polymer compound ET1 was dissolved in 2,2,3,3,4,4,5,5-octafluoro-1-pentanol. The resulting 2,2,3,3,4,4,5,5-octafluoro-1-pentanol solution was used to form a film with a thickness of 20 nm on the light-emitting layer (B) by spin coating, and the film was heated at 130°C for 10 minutes in a nitrogen gas atmosphere to form a second electron transport layer.

[0386] The results of Examples D1 to D4 and Comparative Example CD1 are shown in Table 5. In Table 5, the driving voltage difference [V] indicates the difference in driving voltage [V] of the light-emitting elements D1 to D4 relative to the driving voltage [V] of the light-emitting element CD1.

[0387] [Table 5]

[0388] Examples D5 to D8: Fabrication and evaluation of light-emitting devices D5 to D8 Light-emitting devices D5 to D8 were produced in the same manner as in Example D1, except that in Example D1 (formation of the light-emitting layer (B)), the materials shown in Table 6 were used instead of "compound H1, compound MC1, and compound B1 (compound H1 / compound MC1 / compound B1=73% by mass / 25% by mass / 2% by mass)" and in Example D1 (formation of the first electron transport layer), the materials shown in Table 6 were used instead of "polymer compound ET2." EL emission was observed by applying a voltage to the light-emitting devices D5 to D8. 2 The driving voltage was measured.

[0389] <Comparative Example CD2> Fabrication and Evaluation of Light-Emitting Device CD2 A light-emitting element CD2 was produced in the same manner as in Example D1, except that in the (formation of the light-emitting layer (B)) of Example D1, instead of "Compound H1, Compound MC1, and Compound B1 (Compound H1 / Compound MC1 / Compound B1 = 73% by mass / 25% by mass / 2% by mass)," the materials shown in Table 6 were used, (the formation of the first electron transport layer) was omitted, and (the formation of the second electron transport layer) was the same as in the (formation of the second electron transport layer CD1). EL emission was observed by applying a voltage to the light-emitting element CD2. At a current of 100 mA / cm for the light-emitting element CD2, 2 The driving voltage was measured.

[0390] The results of Examples D5 to D8 and Comparative Example CD2 are shown in Table 6. In Table 6, the driving voltage difference [V] indicates the difference in driving voltage [V] of the light-emitting elements D5 to D8 relative to the driving voltage [V] of the light-emitting element CD2.

[0391] [Table 6]

[0392] Example D9 Fabrication and Evaluation of Light-Emitting Device D9 (Formation of anode and hole injection layer) An anode was formed by sputtering a 45-nm thick ITO film on a glass substrate. A 35-nm thick film of hole injection material ND-3202 (manufactured by Nissan Chemical Co., Ltd.) was spin-coated onto the anode to form a coating. The substrate with the coating was heated on a hot plate in an air atmosphere at 50°C for 3 minutes and then at 230°C for 15 minutes to form a hole injection layer.

[0393] (Formation of hole transport layer) Compound HT2 was dissolved in xylene. The resulting xylene solution was used to form a 20 nm thick film on the hole injection layer by spin coating, and the film was heated at 180°C for 60 minutes on a hot plate under a nitrogen gas atmosphere to form a hole transport layer. This heating caused compound HT2 to become crosslinked.

[0394] (Formation of light-emitting layer (B)) Compound H1, Compound MC1, and Compound B1 (Compound H1 / Compound MC1 / Compound B1 = 73% by mass / 25% by mass / 2% by mass) were dissolved in chlorobenzene. The resulting toluene solution was used to form a film with a thickness of 60 nm on the hole transport layer by spin coating, and the film was heated at 130°C for 10 minutes in a nitrogen gas atmosphere to form an emitting layer (B).

[0395] (Formation of the first electron transport layer) The polymer compound ET2 was dissolved in xylene, and the resulting xylene was used to form a film with a thickness of 10 nm on the light-emitting layer (B) by spin coating. The film was then heated at 130°C for 10 minutes in a nitrogen gas atmosphere to form a first electron transport layer.

[0396] (Formation of the second electron transport layer) The polymer compound ET1 was dissolved in 2,2,3,3,4,4,5,5-octafluoro-1-pentanol, and the resulting 2,2,3,3,4,4,5,5-octafluoro-1-pentanol solution was spin-coated onto the first electron transport layer to form a 10 nm thick film. The film was then heated at 130°C for 10 minutes in a nitrogen gas atmosphere to form a second electron transport layer.

[0397] (Cathode formation) The substrate on which the second electron transport layer was formed was placed in a deposition machine. -4 After reducing the pressure to below 10 Pa, sodium fluoride and aluminum were sequentially vapor-deposited on the second electron transport layer to form an electron injection layer with a thickness of approximately 4 nm and a cathode with a thickness of approximately 80 nm. The substrate with the cathode formed thereon was then sealed with a glass substrate to produce light-emitting device D9.

[0398] (Evaluation of light-emitting elements) EL light emission was observed by applying a voltage to the light-emitting device D9. 2 The driving voltage was measured.

[0399] <Comparative Example CD3> Fabrication and Evaluation of Light-Emitting Device CD3 A light-emitting device CD3 was produced in the same manner as in Example D9, except that the step of Example D9 (formation of the second electron transport layer) was not carried out. EL light emission was observed by applying a voltage to the light-emitting device CD3. 2 The driving voltage was measured.

[0400] The results of Example D9 and Comparative Example CD3 are shown in Table 7. In Table 7, the driving voltage difference [V] indicates the difference in driving voltage [V] of the light-emitting element D9 relative to the driving voltage [V] of the light-emitting element CD3.

[0401] [Table 7]

[0402] Example D10: Fabrication and evaluation of light-emitting device D10 A light-emitting device D10 was fabricated in the same manner as in Example D9 (formation of the first electron transport layer), except that the materials listed in Table 8 were used instead of the "polymer compound ET2" in Example D9 (formation of the first electron transport layer). EL emission was observed by applying a voltage to the light-emitting device D10. 2 The driving voltage was measured.

[0403] <Comparative Example CD4> Fabrication and Evaluation of Light-Emitting Device CD4 A light-emitting device CD4 was fabricated in the same manner as in Example D9, except that the material shown in Table 8 was used instead of the polymer compound ET2 in the (formation of the first electron transport layer) of Example D9, and the (formation of the second electron transport layer) was not performed. EL emission was observed by applying a voltage to the light-emitting device CD4. 2 The driving voltage was measured.

[0404] The results of Example D10 and Comparative Example CD4 are shown in Table 8. In Table 8, the driving voltage difference [V] indicates the difference in driving voltage [V] of the light-emitting element D10 relative to the driving voltage [V] of the light-emitting element CD4.

[0405] [Table 8]

[0406] As is clear from Tables 5 to 8, the light-emitting elements of the examples, which have an anode, a cathode, an emitting layer (B) provided between the anode and the cathode, a first electron transport layer provided between the emitting layer (B) and the cathode, and a second electron transport layer provided between the first electron transport layer and the cathode, have lower driving voltages than the light-emitting elements of the comparative examples, which do not have the first electron transport layer or the second electron transport layer.

Claims

1. A light-emitting device comprising an anode, a cathode, a light-emitting layer provided between the anode and the cathode, a first electron transport layer provided between the light-emitting layer and the cathode, and a second electron transport layer provided between the first electron transport layer and the cathode, The light-emitting layer contains boron atoms, oxygen atoms, sulfur atoms, selenium atoms, sp ３ a layer containing at least one compound selected from the group consisting of a low molecular weight compound (B) having a fused heterocyclic skeleton (b) containing, in the ring, at least one atom selected from the group consisting of a carbon atom and a nitrogen atom, and a polymer compound (B) containing a structural unit having a group in which one or more hydrogen atoms have been removed from the low molecular weight compound (B), the first electron transport layer and the second electron transport layer are layers containing at least one selected from the group consisting of low molecular weight compounds represented by formula (H-1), low molecular weight compounds represented by formula (ET-1), low molecular weight compounds represented by formula (ET-2), and polymer compounds containing at least one structural unit selected from the group consisting of structural units having a group obtained by removing one or more hydrogen atoms from the low molecular weight compound represented by formula (ET-1), structural units having a group obtained by removing one or more hydrogen atoms from the low molecular weight compound represented by formula (ET-2), structural units represented by formula (X), and structural units represented by formula (Y), a light-emitting device, wherein at least one of the first electron transport layer and the second electron transport layer is a layer containing a polymer compound including at least one structural unit selected from the group consisting of a structural unit having a group obtained by removing one or more hydrogen atoms from a low-molecular-weight compound represented by formula (ET-1), a structural unit having a group obtained by removing one or more hydrogen atoms from a low-molecular-weight compound represented by formula (ET-2), a structural unit represented by formula (X), and a structural unit represented by formula (Y). 【Chemical 1】 [In the formula, Ar Ｈ１ and Ar Ｈ２ each independently represents an aryl group, a monovalent heterocyclic group, or a substituted amino 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. n Ｈ１ represents an integer of 0 or greater. L Ｈ１ represents a divalent group, and the divalent group 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. Ｈ１ When a plurality of groups are present, they may be the same or different, and may be bonded to each other directly or via a divalent group to form a ring. Ar Ｈ１ and Ar Ｈ２ may be bonded directly or via a divalent group to form a ring. Ｈ１ and Ar Ｈ１ may be bonded directly or via a divalent group to form a ring. Ｈ１ and Ar Ｈ２ may be bonded directly or via a divalent group to form a ring. 【Chemistry 2】 [In the formula, nE1 represents an integer of 1 or more. Ar Ｅ１ represents an aromatic hydrocarbon group or a heterocyclic group, and these groups may have a substituent. Good too. R Ｅ１ represents a group represented by formula (ES-1). Ｅ１ When there are multiple groups, they may be the same or different. -R Ｅ３ -{(Q Ｅ１ ) ｎＥ３ -Y Ｅ１ (M Ｅ１ ) ａＥ１ (Z Ｅ１ ) ｂＥ１ } ｍＥ１ (ES-1) [In the formula, nE3 and bE1 each independently represent an integer of 0 or more, and aE1 and mE1 each independently represent an integer of 1 or more. When a plurality of nE3, aE1 and bE1 are present, they may be the same or different. Ｅ３ is a single bond, mE1 is 1. aE1 and bE1 are selected so that the charge of the group represented by formula (ES-1) is 0. R Ｅ３ is a single bond, a hydrocarbon group, a heterocyclic group, or O—R Ｅ３’ (R Ｅ３’ represents a hydrocarbon group or a heterocyclic group, and these groups may have a substituent. Q Ｅ１ represents an alkylene group, a cycloalkylene group, an arylene group, an oxygen atom or a sulfur atom, and these groups may have a substituent. Ｅ１ When there are multiple groups, they may be the same or different. Y Ｅ１ is -CO ２ － , -SO ３ － , -SO ２ － or -PO ３ ２－ Represents Y. Ｅ１ When there are multiple groups, they may be the same or different. M Ｅ１ represents an alkali metal cation, an alkaline earth metal cation or an ammonium cation, and the ammonium cation may have a substituent. Ｅ１ When there are multiple groups, they may be the same or different. Z Ｅ１ Is F － , Cl － ,Br － , I － , O.H. － , B(R Ｅ４ ) ４ － , R Ｅ４ SO ３ － , R Ｅ４ COO － , NO ３ － , S.O. ４ ２－ , HSO ４ － , P.O. ４ ３－ , H.P.O. ４ ２－ , H ２ P.O. ４ － , B.F. ４ － or PF ６ － Represents R Ｅ４ represents an alkyl group, a cycloalkyl group or an aryl group, and these groups may have a substituent. Ｅ１ When there are multiple groups, they may be the same or different. 【Chemistry 3】 [In the formula, nE2 represents an integer of 1 or more. Ar Ｅ２ represents an aromatic hydrocarbon group or a heterocyclic group, and these groups may have a substituent. R Ｅ２ represents a group represented by formula (ES-2). Ｅ２ When there are multiple groups, they may be the same or different. -R Ｅ５ -{(Q Ｅ２ ) ｎＥ４ -Y Ｅ２ (M Ｅ２ ) ａＥ２ (Z Ｅ２ ) ｂＥ２ } ｍＥ２ (ES-2) [In the formula, nE4 and bE2 each independently represent an integer of 0 or more, and aE2 and mE2 each independently represent an integer of 1 or more. When a plurality of nE4, aE2, and bE2 are present, they may be the same or different. However, R Ｅ５ is a single bond, mE2 is 1. aE2 and bE2 are selected so that the charge of the group represented by formula (ES-2) is 0. R Ｅ５ is a single bond, a hydrocarbon group, a heterocyclic group, or O—R Ｅ５’ (R Ｅ５’ represents a hydrocarbon group or a heterocyclic group, and these groups may have a substituent. Q Ｅ２ represents an alkylene group, a cycloalkylene group, an arylene group, an oxygen atom or a sulfur atom, and these groups may have a substituent. Ｅ２ When there are multiple groups, they may be the same or different. Y Ｅ２ is -C ＋ R Ｅ６ ２ , -N ＋ R Ｅ６ ３ , -P ＋ R Ｅ６ ３ , -S ＋ R Ｅ６ ２ or- I ＋ R Ｅ６ ２ Represents R Ｅ６ represents a hydrogen atom, an alkyl group, a cycloalkyl group, or an aryl group, and these groups may have a substituent. Ｅ６ may be the same or different. Ｅ２ When there are multiple groups, they may be the same or different. M Ｅ２ Is F － , Cl － ,Br － , I － , O.H. － , B(R Ｅ７ ) ４ － , R Ｅ７ SO ３ － , R Ｅ７ COO － , B.F. ４ － , SbCl ６ － or SbF ６ － Represents R Ｅ７ represents an alkyl group, a cycloalkyl group or an aryl group, and these groups may have a substituent. Ｅ２ When there are multiple groups, they may be the same or different. Z Ｅ２ represents an alkali metal cation or an alkaline earth metal cation. Ｅ２ When there are multiple groups, they may be the same or different. 【Chemistry 4】 [In the formula, a Ｘ１ and a Ｘ２ each independently represents an integer of 0 or more. 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 each independently 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, 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 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 a plurality of R, they may be the same or different. Ｘ３ When there are multiple groups, they may be the same or different. 【Chemistry 5】 [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, 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. ］

2. 2. The light-emitting element according to claim 1, wherein the second electron transport layer is a layer containing a polymer compound including at least one structural unit selected from the group consisting of structural units having a group in which one or more hydrogen atoms have been removed from a low-molecular-weight compound represented by formula (ET-1) and structural units having a group in which one or more hydrogen atoms have been removed from a low-molecular-weight compound represented by formula (ET-2).

3. 3. The light-emitting device according to claim 1, wherein the first electron transport layer is a layer containing a polymer compound including at least one structural unit selected from the group consisting of a structural unit represented by formula (X) and a structural unit represented by formula (Y).

4. 3. The light-emitting device according to claim 1, wherein the fused heterocyclic skeleton (b) contains a boron atom and at least one atom selected from the group consisting of an oxygen atom, a sulfur atom, and a nitrogen atom in the ring.

5. 3. The light-emitting device according to claim 1, wherein the low molecular weight compound (B) is a compound represented by formula (1-1), a compound represented by formula (1-2), or a compound represented by formula (1-3). 【Chemistry 6】 [In the formula, Ar １ , Ar ２ and Ar ３ each independently represents an aromatic hydrocarbon group or a 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. Y １ represents an oxygen atom, a sulfur atom, a selenium atom, a group represented by -N(Ry)-, an alkylene group, or a cycloalkylene group, and these groups may have 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. Y ２ and Y ３ each independently represents a single bond, an oxygen atom, a sulfur atom, a selenium atom, a group represented by -N(Ry)-, a group represented by -B(Ry)-, an alkylene group, a cycloalkylene group, an arylene group, or a divalent heterocyclic group, and these groups may have 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. Ry 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 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 Ry, they may be the same or different. Y １ and Ar １ may be bonded directly or via a divalent group to form a ring. １ and Ar ２ may be bonded directly or via a divalent group to form a ring. ２ and Ar １ may be bonded directly or via a divalent group to form a ring. ２ and Ar ３ may be bonded directly or via a divalent group to form a ring. ３ and Ar ２ is directly bonded or bonded via a divalent group , may form a ring. ３ and Ar ３ may be bonded directly or via a divalent group to form a ring.

6. The Y １ , the Y ２ and the Y ３ and each independently represent an oxygen atom, a sulfur atom, or a group represented by -N(Ry)-.

7. 3. The light-emitting device according to claim 1, wherein the light-emitting layer further comprises at least one compound selected from the group consisting of a metal complex represented by formula (1) and a polymer compound (A) comprising a structural unit having a group in which one or more hydrogen atoms have been removed from the metal complex represented by formula (1): 【Chemistry 7】 [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 the ring 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. Ring L １ When there are multiple groups, they may be the same or different. Ring L ２ 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 L ２ When there are multiple groups, they may be the same or different. Ring L １ and a substituent that may be present on ring L ２ 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. 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.

8. The ring L １ is an aromatic heterocycle containing a 5-membered ring or an aromatic heterocycle containing a 6-membered ring, and these rings may have a substituent, and ring L ２ The light-emitting element according to claim 7 , wherein is an aromatic hydrocarbon ring containing a five-membered ring or a six-membered ring, or an aromatic heterocycle containing a five-membered ring or a six-membered ring, and these rings may have a substituent.

9. 3. The light-emitting device according to claim 1, wherein the light-emitting layer further contains at least one selected from the group consisting of a low molecular weight compound represented by formula (H-1), and a polymer compound comprising at least one structural unit selected from the group consisting of a structural unit represented by formula (X) and a structural unit represented by formula (Y).

10. 3. The light-emitting device according to claim 1, wherein the light-emitting layer further comprises 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.

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

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

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