Charge transport polymer-containing composition, and photoelectric conversion element

Abstract

Provided is a composition that can be suitably used for the formation of a hole transport layer even when a photoelectric conversion element having an active layer containing a perovskite semiconductor compound has an inverted structure. This composition is used for forming a hole transport layer of a photoelectric conversion element and contains a charge transport polymer (α) and a tetraarylborate ion, wherein the charge transport polymer (α) has a crosslinkable group and further has a chemical structure of formula (5) in its main chain, and the tetraarylborate ion is represented by formula (4). Note that R1 denotes an alkyl group having 1 to 4 carbon atoms, R2 to R5 each independently denote a hydrogen atom or the like, Ar31, Ar32, Ar33, and Ar34 each independently denote an optionally substituted aromatic hydrocarbon group or the like, and at least one of Ar31, Ar32, Ar33, and Ar34 has a fluorine atom or a fluorine-substituted alkyl group as a substituent.

Description

Composition containing charge transport polymer and photoelectric conversion element

[0001] The present invention relates to a composition containing a charge transport polymer and a photoelectric conversion element. This application claims priority to Japanese Patent Application No. 2024-073535, filed on April 30, 2024, the contents of which are incorporated herein by reference.

[0002] Photoelectric conversion elements have an active layer, a buffer layer, etc., arranged between a pair of electrodes. Organic-inorganic hybrid semiconductor compounds have been developed as materials for this active layer, and compounds with a perovskite structure (perovskite semiconductor compounds) have attracted particular attention.

[0003] Organic semiconductor compounds and the like are used for the hole transport layer in photoelectric conversion elements. In particular, in recent years, polymers having aromatic amine structural units have been used as materials for the hole transport layer because they are expected to contribute to power generation efficiency due to their high charge mobility and because they are soluble in solvents and can be formed into layers by coating (Patent Document 1, Patent Document 2).

[0004] International Publication No. 2017 / 018529 Japanese Patent Application Laid-Open No. 2022-145231

[0005] However, when the hole transport layer materials of conventional photoelectric conversion elements are applied to photoelectric conversion elements with an inverted structure, in which the active layer is formed after the hole transport layer, they have poor resistance to the perovskite coating process and can be damaged. Therefore, in an inverted structure, a cross-linked hole transport layer is preferred, but cross-linked hole transport layers formed from conventional materials can repel the active layer ink containing a perovskite semiconductor compound when the active layer ink is applied, resulting in reduced power generation efficiency and durability.

[0006] The present invention provides a composition that can be suitably applied to the formation of a hole transport layer even when a photoelectric conversion element having an active layer containing a perovskite semiconductor compound has an inverted structure.The present invention also provides a charge transport polymer that can be suitably applied to the formation of a hole transport layer even when a photoelectric conversion element having an active layer containing a perovskite semiconductor compound has an inverted structure.

[0007] As a result of extensive investigations, the present inventors have found that the above-mentioned problems can be solved by using a charge-transporting polymer having a specific unit having a crosslinkable group as a material for the hole-transporting layer, and have thus completed the present invention.

[0008] The present invention has the following aspects: [1] A composition for forming a hole transport layer of a photoelectric conversion element, comprising a charge transport polymer (α) and a tetraarylborate ion, wherein the charge transport polymer (α) has a crosslinkable group and further has a chemical structure of the following formula (5) in its main chain, and the tetraarylborate ion is represented by the following formula (4).

[0009]

[0010] In formula (5), R １ represents an alkyl group having 1 to 4 carbon atoms, and R ２ ~R ５ each independently represents a hydrogen atom; an alkyl group having 1 to 24 carbon atoms; an aryloxy group having 4 to 36 carbon atoms; an alkoxycarbonyl group having 2 to 24 carbon atoms; a dialkylamino group having 2 to 24 carbon atoms; an acyl group having 2 to 24 carbon atoms; a halogen atom; a haloalkyl group having 1 to 12 carbon atoms; an alkylthio group having 1 to 24 carbon atoms; an arylthio group having 4 to 36 carbon atoms; a siloxy group having 2 to 36 carbon atoms; a cyano group; an aromatic hydrocarbon group having 6 to 36 carbon atoms; or an aromatic heterocyclic group having 3 to 36 carbon atoms; ２ ~R ５ each group may be substituted with one or more groups selected from the group consisting of an alkyl group having 1 to 24 carbon atoms; an aryloxy group having 4 to 36 carbon atoms; an alkoxycarbonyl group having 2 to 24 carbon atoms; a dialkylamino group having 2 to 24 carbon atoms; an acyl group having 2 to 24 carbon atoms; a halogen atom; a haloalkyl group having 1 to 12 carbon atoms; an alkylthio group having 1 to 24 carbon atoms; an arylthio group having 4 to 36 carbon atoms; a siloxy group having 2 to 36 carbon atoms; a cyano group; an aromatic hydrocarbon group having 6 to 36 carbon atoms; and an aromatic heterocyclic group having 3 to 36 carbon atoms; ２ ~R ４ Two adjacent groups among these may be bonded to each other to form a ring.

[0011]

[0012] In formula (4), Ar ３１ , Ar ３２ , Ar ３３ , and Ar ３４ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, ３１ , Ar ３２ , Ar ３３ , and Ar ３４ At least one of the groups has a fluorine atom or a fluorine-substituted alkyl group as a substituent. [2] A composition for forming a hole transport layer of a photoelectric conversion element, comprising a charge transport polymer (α) and a tetraarylborate ion, wherein the charge transport polymer (α) has a chemical structure of formula (5) described in [1] in its main chain, and further has at least one group selected from the crosslinkable group group T described in [8], and the tetraarylborate ion is represented by formula (4) described in [1]. [3] The composition of [1] or [2], wherein the charge transport polymer (α) has a unit represented by formula (1) described in [5], (2) described in [6], or (3) described in [7]. [4] The composition of any of [1] to [3], wherein the charge transport polymer (α) has a unit represented by formula (1) described in [5] or (3) described in [7]. [5] The composition of any of [1] to [4], wherein the charge transport polymer (α) has a unit represented by formula (1):

[0013]

[0014] In formula (1), R １１ represents a hydrogen atom, an alkyl group having 1 to 24 carbon atoms which may have a substituent, an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, １１ represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent, １２ , Ar １３ , and Ar １４ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, １represents a crosslinkable group. １１ In the formula (6), at least one atom adjacent to the atom bonded to the nitrogen atom is bonded to an alkyl group having 1 to 4 carbon atoms. [6] The composition of any one of the formulas (1) to (3), wherein the charge transporting polymer (α) has a unit represented by the following formula (2):

[0015]

[0016] In formula (2), Ar １５ , Ar １６ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, １ represents a crosslinkable group. １５ In the formula (7), at least one atom adjacent to the atom bonded to the nitrogen atom is bonded to an alkyl group having 1 to 4 carbon atoms.

[0017]

[0018] In formula (3), Ar １７ , Ar １８ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, １ represents a crosslinkable group. １７ In the formula (8), at least one atom adjacent to the atom bonded to the nitrogen atom is bonded to an alkyl group having 1 to 4 carbon atoms. [8] The composition of any one of [1] and [3] to [7], wherein the crosslinkable group is at least one group selected from the following group T of crosslinkable groups:

[0019]

[0020] In the formula, R ２４ , R ２５ , and R ２６ each independently represents a hydrogen atom or an alkyl group, ２７ , R ２８ , and R ２９ each independently represents an alkyl group or an alkoxy group, Ar２１ , and Ar ２２ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent; p represents an integer of 0 to 4; q represents an integer of 0 to 5; r represents an integer of 0 to 7; and * represents a bond.

[0021] [9] A photoelectric conversion element having a pair of electrodes having an upper electrode and a lower electrode, an active layer located between the pair of electrodes and containing an organic-inorganic hybrid semiconductor compound, and a hole transport layer located between the active layer and the upper electrode or the active layer and the lower electrode, the photoelectric conversion element containing the composition of any of [1] to [8].

[10] A photoelectric conversion element having a pair of electrodes having an upper electrode and a lower electrode, an active layer located between the pair of electrodes and containing an organic-inorganic hybrid semiconductor compound, and a hole transport layer located between the active layer and the upper electrode or the active layer and the lower electrode, the hole transport layer containing a crosslinked product of any of the compositions of [1] to [8].

[0022] The present invention also has the following aspects: <1> A charge transporting polymer having a unit represented by the following formula (1).

[0023]

[0024] In formula (1), R １１ represents a hydrogen atom, an alkyl group having 1 to 24 carbon atoms which may have a substituent, an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent; Ar １１ represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent, Ar １２ , Ar １３ , and Ar １４ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, and T １ represents a crosslinkable group. １１At least one atom of the atoms adjacent to the atom bonded to the nitrogen atom is bonded to an alkyl group having 1 to 4 carbon atoms. <2> A charge transporting polymer having a unit represented by the following formula (2):

[0025]

[0026] In formula (2), Ar １５ , Ar １６ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, and T １ represents a crosslinkable group. １５ At least one atom of the atoms adjacent to the atom bonded to the nitrogen atom is bonded to an alkyl group having 1 to 4 carbon atoms. <3> A charge transporting polymer having a unit represented by the following formula (3):

[0027]

[0028] In formula (3), Ar １７ , Ar １８ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, and T １ represents a crosslinkable group. １７ In the formula (4), at least one atom adjacent to the atom bonded to the nitrogen atom is bonded to an alkyl group having 1 to 4 carbon atoms.

[0029]

[0030] In the formula, R ２４ , R ２５ , and R ２６ each independently represents a hydrogen atom or an alkyl group, and R ２７ , R ２８ , and R ２９ each independently represents an alkyl group or an alkoxy group, Ar ２１ , and Ar ２２each independently represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent, p represents an integer of 0 to 4, q represents an integer of 0 to 5, r represents an integer of 0 to 7, and * represents a bond.

[0031] <5> A composition for forming a hole transport layer of a photoelectric conversion element, comprising the charge transport polymer according to any one of <1> to <4>, wherein the photoelectric conversion element comprises a pair of electrodes having an upper electrode and a lower electrode, an active layer located between the pair of electrodes and containing an organic-inorganic hybrid semiconductor compound, and a hole transport layer located between the active layer and the upper electrode or the lower electrode. <6> The composition according to <5>, further comprising a tetraarylborate ion represented by the following formula (4) as an electron-accepting compound for the charge transport polymer:

[0032]

[0033] In formula (4), Ar ３１ , Ar ３２ , Ar ３３ , and Ar ３４ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, and Ar ３１ , Ar ３２ , Ar ３３ , and Ar ３４ <7> A photoelectric conversion element comprising: a pair of electrodes having an upper electrode and a lower electrode; an active layer located between the pair of electrodes and containing an organic-inorganic hybrid semiconductor compound; and a hole transport layer located between the active layer and the upper electrode or the lower electrode, wherein the hole transport layer comprises a crosslinked product of a charge transport polymer according to any one of <1> to <4>.

[0034] <8> A composition containing a charge-transporting polymer (α) and a tetraarylborate ion, wherein the charge-transporting polymer (α) has a crosslinkable group and further has a chemical structure of formula (5) described in [1] in a main chain, and the tetraarylborate ion is represented by formula (4) described in [1].

[0035] According to the present invention, it is possible to provide a composition that can be suitably applied to the formation of a hole transport layer even when a photoelectric conversion element having an active layer containing a perovskite semiconductor compound has an inverted structure. Furthermore, according to the present invention, it is possible to provide a charge transport polymer that can be suitably applied to the formation of a hole transport layer even when a photoelectric conversion element having an active layer containing a perovskite semiconductor compound has an inverted structure.

[0036] Fig. 1 schematically shows an example of a photoelectric conversion element, Fig. 2 schematically shows an example of a solar cell including a photoelectric conversion element, and Fig. 3 schematically shows an example of a solar cell module including a photoelectric conversion element.

[0037] Hereinafter, several embodiments will be described with reference to the drawings. However, the following description is of typical examples, and the present invention is not limited to the following description. The dimensional ratios in the drawings are for the convenience of explanation and may differ from the actual ones.

[0038] [Composition] The composition of the present invention is a composition for forming a hole transport layer of a photoelectric conversion element, and contains a charge transport polymer (α) and a tetraarylborate ion. The charge transport polymer (α) has a crosslinkable group and further has a chemical structure of formula (5) in its main chain. The tetraarylborate ion is represented by formula (4). Formulas (5) and (4) will be described in detail later.

[0039] The composition of the present invention may contain one or more charge transporting polymers (α). The composition of the present invention may contain one or more tetraarylborate ions.

[0040] [Charge-Transporting Polymer (α)] The charge-transporting polymer (α) has a crosslinking group and further has a chemical structure of the following formula (5) in the main chain.

[0041]

[0042] In formula (5), R １ represents an alkyl group having 1 to 4 carbon atoms, and R ２ ~R ５ each independently represents a hydrogen atom; an alkyl group having 1 to 24 carbon atoms; an aryloxy group having 4 to 36 carbon atoms; an alkoxycarbonyl group having 2 to 24 carbon atoms; a dialkylamino group having 2 to 24 carbon atoms; an acyl group having 2 to 24 carbon atoms; a halogen atom; a haloalkyl group having 1 to 12 carbon atoms; an alkylthio group having 1 to 24 carbon atoms; an arylthio group having 4 to 36 carbon atoms; a siloxy group having 2 to 36 carbon atoms; a cyano group; an aromatic hydrocarbon group having 6 to 36 carbon atoms; or an aromatic heterocyclic group having 3 to 36 carbon atoms; ２ ~R ５ each group may be substituted with one or more groups selected from the group consisting of an alkyl group having 1 to 24 carbon atoms; an aryloxy group having 4 to 36 carbon atoms; an alkoxycarbonyl group having 2 to 24 carbon atoms; a dialkylamino group having 2 to 24 carbon atoms; an acyl group having 2 to 24 carbon atoms; a halogen atom; a haloalkyl group having 1 to 12 carbon atoms; an alkylthio group having 1 to 24 carbon atoms; an arylthio group having 4 to 36 carbon atoms; a siloxy group having 2 to 36 carbon atoms; a cyano group; an aromatic hydrocarbon group having 6 to 36 carbon atoms; and an aromatic heterocyclic group having 3 to 36 carbon atoms;

[0043] R ２ ~R ４ Two adjacent groups among these may be bonded to each other to form a ring.

[0044] R １ Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group. In terms of high adhesion to the active layer containing the perovskite semiconductor compound and excellent charge transport properties, a methyl group and an ethyl group are preferred, and a methyl group is more preferred. In terms of high steric hindrance and excellent polymer solubility, an isopropyl group and a tert-butyl group are preferred. Note that, as will be described later, Ar １１ , Ar １５ , and Ar １７ The same applies to the alkyl group having 1 to 4 carbon atoms.

[0045] R ２ ~R ５ The embodiments other than the hydrogen atom are the same as those of the substituent group Z1 described later.

[0046] R ２ ~R ４ Among these, examples of the ring formed by bonding two adjacent groups to each other (the ring fused to the benzene ring bonded to the nitrogen atom in formula (5)) include a benzene ring, a naphthalene ring, an acenaphthylene ring, a fluorene ring, a phenalene ring, a phenanthrene ring, an anthracene ring, a pyrrole ring, an oxazole ring, a thiazole ring, an isothiazole ring, an imidazole ring, a thiadiazole ring, a triazole ring, a pyrazole ring, a pyridine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, an indole ring, a benzimidazole ring, a benzoxazole ring, a benzothiazole ring, a quinoline ring, an isoquinoline ring, a quinazoline ring, a quinoxaline ring, a carbazole ring, an acridine ring, a phenoxazine ring, a phenothiazine ring, a furan ring, a benzofuran ring, a dibenzofuran ring, a thiophene ring, a benzothiophene ring, and a dibenzothiophene ring. These rings are preferably fused to improve heat resistance.

[0047] The crosslinkable group contained in the charge transporting polymer (α) may be a group selected from the group T of crosslinkable groups described below.

[0048] Examples of the chemical structure represented by formula (5) include units represented by the following formulas (1), (2), and (3).

[0049]

[0050] In formula (1), R １１ represents a hydrogen atom, an alkyl group having 1 to 24 carbon atoms which may have a substituent, an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent; Ar １１ represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent, Ar １２ , Ar １３ , and Ar １４ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, and T１ represents a crosslinkable group. １１ In the formula (I), at least one atom adjacent to the atom bonded to the nitrogen atom is bonded to an alkyl group having 1 to 4 carbon atoms.

[0051]

[0052] In formula (2), Ar １５ , Ar １６ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, and T １ represents a crosslinkable group. １５ In the formula (I), at least one atom adjacent to the atom bonded to the nitrogen atom is bonded to an alkyl group having 1 to 4 carbon atoms.

[0053]

[0054] In formula (3), Ar １７ , Ar １８ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, and T １ represents a crosslinkable group. １７ In the formula (I), at least one atom adjacent to the atom bonded to the nitrogen atom is bonded to an alkyl group having 1 to 4 carbon atoms.

[0055] A polymer having the chemical structure of formula (5) in its main chain, or a polymer having a unit represented by formula (1), formula (2), or formula (3), has an alkyl group having 1 to 4 carbon atoms at a predetermined position in its side chain. Therefore, significant steric hindrance exists between the two aromatic groups forming the main chain and the aromatic hydrocarbon group or aromatic heterocyclic group forming the side chain. Therefore, the charge-transporting polymer (α) has excellent solubility in organic solvents. Generally, polymers having aromatic ring structural units are substituted with long-chain alkyl groups to dissolve them in solvents used during coating, but this is not necessary for the charge-transporting polymer (α).

[0056] Generally, alkyl groups cause a decrease in adhesion to layers containing inorganic substances. However, the charge-transporting polymer (α) has improved solubility in solvents due to the large steric hindrance caused by the alkyl groups having 1 to 4 carbon atoms present at the ortho positions of the side chains, making it possible to reduce the amount of alkyl groups present on the film surface after film formation. Therefore, the charge-transporting polymer (α) has excellent adhesion to an active layer containing an organic-inorganic hybrid semiconductor compound, and can contribute to improving the power generation efficiency and durability of photoelectric conversion elements.

[0057] Since the charge transport polymer (α) has a crosslinkable group, its solubility in a solvent can be reduced by irradiation with heat and / or active energy rays after the coating film formation. In a photoelectric conversion element with an inverted structure, the hole transport layer is formed and then the active layer is coated. In general, if the lower layer (here, the hole transport layer) dissolves in the coating solvent for the upper layer (here, the active layer), the element performance will be reduced or will vary.

[0058] The charge transporting polymer (α) after crosslinking has reduced solubility in a solvent, and is therefore less susceptible to the influence of the coating solvent of the active layer when the active layer is applied. Therefore, the charge transporting polymer (α) is less susceptible to the influence of the coating of the active layer on the film shape and physical properties, and can contribute to improving the power generation efficiency and durability of an inverted photoelectric conversion element.

[0059] In the charge-transporting polymer, the crosslinkable group is preferably bonded to a carbon atom having four single bonds in the main chain via an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent. This is because the molecular orbitals of the charge-transporting moiety and the crosslinking moiety are separated, thereby suppressing a decrease in charge-transporting properties due to the crosslinkable group.

[0060] The structure represented by formula (1) has an aromatic amine structure in addition to a crosslinkable group, and therefore has an improved hole transporting property.

[0061]

[0062] In formula (1), R １１represents a hydrogen atom, an alkyl group having 1 to 24 carbon atoms which may have a substituent, an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent; Ar １１ represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent, Ar １２ , Ar １３ , and Ar １４ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, and T １ represents a crosslinkable group. １１ In the formula (I), at least one atom adjacent to the atom bonded to the nitrogen atom is bonded to an alkyl group having 1 to 4 carbon atoms.

[0063] R １１ Examples of the alkyl group having 1 to 24 carbon atoms include linear, branched, and cyclic alkyl groups, and alkyl groups having 1 to 12 carbon atoms are preferred, and alkyl groups having 1 to 6 carbon atoms are preferred, and among these, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, and a cyclohexyl group are preferred in terms of achieving an excellent balance between solubility and charge transportability.

[0064] R １１ is preferably a hydrogen atom from the viewpoint of charge transport properties.

[0065] In another embodiment, R １１ From the viewpoint of solubility, the alkyl group is preferably an alkyl group having 1 to 24 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms, and even more preferably an alkyl group having 1 to 6 carbon atoms.

[0066] R １１ Examples of the aromatic hydrocarbon group of R include groups derived from the aromatic hydrocarbon group P1 described below. １１ Examples of the aromatic heterocyclic group of R include groups derived from the aromatic heterocyclic group P2 described below. Examples of the substituent that the aromatic hydrocarbon group or aromatic heterocyclic group may have include one or more types selected from the substituent group Z1 described below. １１In terms of durability, is preferably an aromatic hydrocarbon group which may have a substituent, and more preferably an aromatic hydrocarbon group.

[0067] Aromatic hydrocarbon group P1: a 6-membered monocyclic ring or 2- to 5-condensed ring, or a ring formed by bonding these, such as a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, a tetracene ring, a pyrene ring, a benzpyrene ring, a chrysene ring, a triphenylene ring, an acenaphthene ring, a fluoranthene ring, or a fluorene ring.

[0068] As the aromatic hydrocarbon group P1, a benzene ring or a naphthalene ring is preferred from the viewpoint of solubility.

[0069] Aromatic heterocyclic ring group P2: a 5- or 6-membered monocyclic ring or 2- to 4-fused ring, or a ring formed by bonding thereof, such as a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrrole ring, a pyrazole ring, an imidazole ring, an oxadiazole ring, an indole ring, a carbazole ring, a pyrroloimidazole ring, a pyrrolopyrazole ring, a pyrrolopyrrole ring, a thienopyrrole ring, a thienothiophene ring, a furopyrrole ring, a furofuran ring, a thienofuran ring, a benzisoxazole ring, a benzisothiazole ring, a benzimidazole ring, a pyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidine ring, a triazine ring, a quinoline ring, an isoquinoline ring, a cinnoline ring, a quinoxaline ring, a phenanthridine ring, a benzimidazole ring, a perimidine ring, a quinazoline ring, a quinazolinone ring, or an azulene ring.

[0070] As the aromatic heterocyclic group P2, a pyridine ring and a quinoline ring are preferred from the viewpoint of solubility.

[0071] Substituent group Z1: alkyl groups preferably having 1 to 24 carbon atoms, more preferably 1 to 12 carbon atoms, such as a methyl group or an ethyl group; aryloxy groups preferably having 4 to 36 carbon atoms, more preferably 5 to 24 carbon atoms, such as a phenoxy group, a naphthoxy group or a pyridyloxy group; alkoxycarbonyl groups preferably having 2 to 24 carbon atoms, more preferably 2 to 12 carbon atoms, such as a methoxycarbonyl group or an ethoxycarbonyl group; dialkylamino groups preferably having 2 to 24 carbon atoms, more preferably 2 to 12 carbon atoms, such as a dimethylamino group or a diethylamino group; acyl groups preferably having 2 to 24 carbon atoms, preferably 2 to 12 carbon atoms, such as an acetyl group or a benzoyl group; halogen atoms such as a fluorine atom or a chlorine atom; haloalkyl groups preferably having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, such as a trifluoromethyl group; alkylthio groups preferably having 1 to 24 carbon atoms, more preferably 1 to 12 carbon atoms, such as a methylthio group or an ethylthio group; Arylthio groups preferably having 4 to 36 carbon atoms, more preferably 5 to 24 carbon atoms, such as a phenylthio group, a naphthylthio group, or a pyridylthio group; siloxy groups preferably having 2 to 36 carbon atoms, more preferably 3 to 24 carbon atoms, such as a trimethylsiloxy group or a triphenylsiloxy group; cyano groups; aromatic hydrocarbon groups preferably having 6 to 36 carbon atoms, more preferably 6 to 24 carbon atoms, such as a phenyl group or a naphthyl group; and aromatic heterocyclic groups preferably having 3 to 36 carbon atoms, more preferably 4 to 24 carbon atoms, such as a thienyl group or a pyridyl group.

[0072] Each of the above substituents may further have a substituent, examples of which include the groups exemplified in the above-mentioned group Z1 of substituents.

[0073] The formula weight of each group in the substituent group Z1, including further substituted groups, is preferably 500 or less, more preferably 250 or less.

[0074] The substituent group Z1 is preferably an alkyl group or an aromatic hydrocarbon group.

[0075] Ar １１ represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent, and Ar １１In the above, at least one atom adjacent to the atom bonded to the nitrogen atom is bonded to an alkyl group having 1 to 4 carbon atoms. For example, Ar １１ When is a phenyl group, "atoms adjacent to the atom bonded to the nitrogen atom" means the carbon atom at the 2nd position, which is the ortho position, and the carbon atom at the 6th position.

[0076] Ar １１ From the viewpoint of improving mobility, is preferably an aromatic hydrocarbon group which may have a substituent, more preferably a phenyl group which may have a substituent, and even more preferably a phenyl group in which the carbon atom at the 2-position and the carbon atom at the 6-position are substituted with an alkyl group having 1 to 4 carbon atoms.

[0077] Ar １２ , Ar １３ , and Ar １４ Examples of the aromatic hydrocarbon group include groups derived from the aromatic hydrocarbon group P1. １２ , Ar １３ , and Ar １４ Examples of the aromatic heterocyclic group include groups derived from the aromatic heterocyclic group P2. Examples of the substituent that the aromatic hydrocarbon group or aromatic heterocyclic group may have include one or more substituents selected from the substituent group Z1.

[0078] Crosslinkable Group Group T: The crosslinkable group is preferably a group selected from the following crosslinkable group T in terms of charge transportability and small interaction with the electron-accepting compound.

[0079]

[0080] In the formula, R ２４ , R ２５ , and R ２６ each independently represents a hydrogen atom or an alkyl group, ２７ , R ２８ , and R ２９ each independently represents an alkyl group or an alkoxy group, Ar ２１ , Ar ２２represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent; p represents an integer of 0 to 4; q represents an integer of 0 to 5; r represents an integer of 0 to 7; and * represents a bond.

[0081] R ２４ , R ２５ , and R ２６ R is preferably a hydrogen atom in view of high reactivity. In another embodiment, R is preferably an alkyl group in view of high stability. ２７ , R ２８ , and R ２９ is preferably a hydrogen atom, since it has less steric hindrance and facilitates ring-opening of the cyclobutene ring. In another embodiment, an alkyl group or an alkoxy group is preferred, since it reduces the activation energy of ring-opening.

[0082] Ar ２１ , and Ar ２２ Examples of the aromatic hydrocarbon group include groups derived from the aromatic hydrocarbon group P1. ２１ , and Ar ２２ Examples of the aromatic heterocyclic group include groups derived from the aromatic heterocyclic group P2. Examples of the substituent that the aromatic hydrocarbon group or aromatic heterocyclic group may have include one or more substituents selected from the substituent group Z1.

[0083] Other crosslinkable groups include cyclic ether groups such as an epoxy group and an oxetane group, and cationic polymerizable groups such as a vinyl ether group.

[0084] (Unit represented by formula (2)) In the charge transporting polymer, the crosslinkable group is preferably bonded to an aromatic group in the main chain, because this improves the balance between charge transporting properties and durability.

[0085] The structure represented by formula (2) has an aromatic amine structure in addition to a crosslinkable group, and therefore has an improved hole transporting property.

[0086]

[0087] In formula (2), Ar １５ , Ar １６each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, and T １ represents a crosslinkable group. １５ In the formula (I), at least one atom adjacent to the atom bonded to the nitrogen atom is bonded to an alkyl group having 1 to 4 carbon atoms.

[0088] Ar １５ , Ar １６ Examples of the aromatic hydrocarbon group include groups derived from the aromatic hydrocarbon group P1. １５ , Ar １６ Examples of the aromatic heterocyclic group include groups derived from the aromatic heterocyclic group P2. Examples of the substituent that the aromatic hydrocarbon group or aromatic heterocyclic group may have include one or more substituents selected from the substituent group Z1.

[0089] Ar １５ From the viewpoint of improving the mobility, T is preferably an aromatic hydrocarbon group which may have a substituent, more preferably a phenyl group which may have a substituent, and even more preferably a phenyl group in which the carbon atom at the 2nd position and the carbon atom at the 6th position are substituted with an alkyl group having 1 to 4 carbon atoms. １ is preferably a group selected from the group T of crosslinkable groups described above.

[0090] (Unit represented by formula (3)) In the charge transport polymer, it is preferable that the crosslinkable group is bonded to a nitrogen atom in the main chain. This is because the charge transport property is excellent and the crosslinkable group is easily mobile, accelerating the crosslinking reaction. It is also preferable that the crosslinkable group is present from the nitrogen atom in the main chain via an aromatic hydrocarbon group or an aromatic heterocyclic group. This is because the distance between the charge transport moiety and the crosslinking moiety is increased, thereby suppressing a decrease in charge transport property due to the crosslinkable group.

[0091] In the structure represented by formula (3), a crosslinkable group is bonded to a nitrogen atom in the main chain, and the hole transport property is enhanced.

[0092]

[0093] In formula (3), Ar １７ , Ar１８ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, and T １ represents a crosslinkable group. １７ In the formula (I), at least one atom adjacent to the atom bonded to the nitrogen atom is bonded to an alkyl group having 1 to 4 carbon atoms.

[0094] Ar １７ , Ar １８ Examples of the aromatic hydrocarbon group include groups derived from the aromatic hydrocarbon group P1. １７ , Ar １８ Examples of the aromatic heterocyclic group include groups derived from the aromatic heterocyclic group P2. Examples of the substituent that the aromatic hydrocarbon group or aromatic heterocyclic group may have include one or more substituents selected from the substituent group Z1.

[0095] Ar １７ From the viewpoint of improving the mobility, T is preferably an aromatic hydrocarbon group which may have a substituent, more preferably a phenylene group which may have a substituent, and even more preferably a phenylene group in which the carbon atom at the 2nd position and the carbon atom at the 6th position are substituted with an alkyl group having 1 to 4 carbon atoms. １ is preferably a group selected from the group T of crosslinkable groups described above.

[0096] The charge transporting polymer (α) may be any of a random copolymer, an alternating copolymer, a block copolymer, and a graft copolymer, and the order of the monomer arrangement is not limited.

[0097] When the charge-transporting polymer (α) has units represented by formula (1), formula (2), or formula (3), and when the charge-transporting polymer (α) is a copolymer, the proportion of the units represented by formula (1), formula (2), or formula (3) relative to 100 mol% of all monomer units is preferably 0.1 mol% to 60 mol%, more preferably 1 mol% to 50 mol%, even more preferably 5 mol% to 40 mol%, and particularly preferably 10 mol% to 30 mol%. When the charge-transporting polymer (α) is a copolymer having two or more of the units represented by formula (1), formula (2), and formula (3), the proportion of the total of the units represented by formula (1), formula (2), or formula (3) relative to 100 mol% of all monomer units is preferably 0.1 mol% to 60 mol%, more preferably 1 mol% to 50 mol%, even more preferably 5 mol% to 40 mol%, and particularly preferably 10 mol% to 30 mol%.

[0098] The weight-average molecular weight of the charge transport polymer (α) is preferably high because it tends to increase the durability of the photoelectric conversion element and the retention rate of the photoelectric conversion efficiency. Furthermore, a low weight-average molecular weight is preferable from the viewpoint of cost and solubility in solvents. Specifically, it is preferably 4,000 or more, more preferably 5,000 or more, even more preferably 6,000 or more, even more preferably 7,000 or more, particularly preferably 8,000 or more, and particularly preferably 9,000 or more. Furthermore, it is preferably 300,000 or less, more preferably 200,000 or less, even more preferably 100,000 or less, even more preferably 80,000 or less, particularly preferably 50,000 or less, and particularly preferably 40,000 or less. The above upper and lower limits can be combined arbitrarily. For example, it may be 4,000 to 300,000, 5,000 to 200,000, 6,000 to 100,000, 7,000 to 80,000, 8,000 to 50,000, or 9,000 to 40,000.

[0099] The number average molecular weight of the charge transporting polymer (α) is preferably 5,000 or more, more preferably 7,000 or more, and is preferably 200,000 or less, more preferably 80,000 or less, and even more preferably 40,000 or less. The above upper and lower limits can be combined arbitrarily. For example, it may be 5,000 to 200,000, 5,000 to 80,000, or 7,000 to 40,000.

[0100] The number average molecular weight and weight average molecular weight of the charge transporting polymer are the number average and weight average molecular weights measured by GPC in terms of polystyrene.

[0101] The method for synthesizing the charge-transporting polymer (α) is not particularly limited, but it can be polymerized using two types of monomers: an arylamine compound and a dibromo compound. For example, it can be synthesized by the method described in JP 2009-263665 A. It can also be synthesized by oxidative polymerization or a coupling reaction using a transition metal catalyst. The number-average molecular weight and weight-average molecular weight of the charge-transporting polymer (α) can be adjusted by the reaction temperature, reaction time, catalyst, etc.

[0102] [Content of Charge-Transporting Polymer (α) in Composition] The content of the charge-transporting polymer (α) in the composition of the present invention may be 0.01% by mass or more and 70% by mass or less, 0.1% by mass or more and 60% by mass or less, or 0.5% by mass or more and 50% by mass or less, based on 100% by mass of the composition. When the content is within the above range, defects are unlikely to occur in the formed hole-transporting layer, and film thickness unevenness is unlikely to occur, which is preferable.

[0103] [Electron Accepting Compound] The composition of the present invention contains a tetraarylborate ion as the electron accepting compound. The electron accepting compound is preferably a compound having oxidizing power and the ability to accept one electron from the charge transporting polymer of the present invention. Specifically, an electron accepting compound having an electron affinity of 4.0 eV or more is preferred, and an electron accepting compound having an electron affinity of 5.0 eV or more is more preferred. In particular, a tetraarylborate ion having an electron affinity of 4.0 eV or more is preferred, and a tetraarylborate ion having an electron affinity of 5.0 eV or more is more preferred.

[0104] The tetraarylborate ion contained in the composition of the present invention is a compound represented by the following formula (4): The tetraarylborate ion represented by formula (4) is preferable in that it is thermally and chemically stable and has high solubility in organic solvents.

[0105]

[0106] In formula (4), Ar ３１ , Ar ３２ , Ar ３３ , and Ar ３４ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, ３１ , Ar ３２ , Ar ３３ , and Ar ３４ At least one of the groups has a fluorine atom or a fluorine-substituted alkyl group as a substituent.

[0107] Ar ３１ , Ar ３２ , Ar ３３ , and Ar ３４ Examples of the aromatic hydrocarbon group include groups derived from the aromatic hydrocarbon group P1. ３１ , Ar ３２ , Ar ３３ , and Ar ３４ Examples of the aromatic heterocyclic group include groups derived from the aromatic heterocyclic group P2.

[0108] Examples of the substituent that the aromatic hydrocarbon group or aromatic heterocyclic group may have include one or more types selected from the above-mentioned substituent group Z1.

[0109] Ar ３１ , Ar ３２ , Ar ３３ , and Ar ３４In the fluorine atom or fluorine-substituted alkyl group that at least one of the above has as a substituent, the fluorine-substituted alkyl group is a group in which all or some of the hydrogen atoms of the alkyl group have been substituted with fluorine atoms, and a group in which all of the hydrogen atoms of the alkyl group have been substituted with fluorine atoms is preferred in terms of strong electron-withdrawing property, and a trifluoromethyl group or a pentafluoroethyl group is preferred in terms of resistance to aggregation.

[0110] The content of the tetraarylborate ion in the composition of the present invention is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, even more preferably 0.05 parts by mass or more, particularly preferably 0.1 parts by mass or more, and is preferably 50 parts by mass or less, more preferably 25 parts by mass or less, and even more preferably 15 parts by mass or less, relative to 100 parts by mass of the charge-transporting polymer (α) contained in the composition. When the content is equal to or greater than the above-mentioned lower limit, the conductivity is likely to be improved. When the content is equal to or less than the above-mentioned upper limit, the generation of leakage current in the photoelectric light-emitting element is likely to be suppressed. The above-mentioned upper and lower limits can be arbitrarily combined. For example, the content may be 0.001 to 50 parts by mass, 0.01 to 50 parts by mass, 0.05 to 25 parts by mass, or 0.1 to 15 parts by mass, relative to 100 parts by mass of the charge-transporting polymer (α) contained in the composition.

[0111] [Solvent] The composition of the present invention may further contain a solvent in addition to the charge transporting polymer (α) and the tetraarylborate ion. The solvent is preferably a solvent that dissolves the charge transporting polymer (α) and the tetraarylborate ion. In one embodiment, a solvent that dissolves the charge transporting polymer (α) at ​​room temperature is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more.

[0112] Examples of the solvent include aromatic solvents such as toluene, xylene, mesitylene, and cyclohexylbenzene; halogen-containing solvents such as 1,2-dichloroethane, chlorobenzene, and o-dichlorobenzene; aliphatic ether solvents such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate; aromatic ether solvents such as 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, and 2,4-dimethylanisole; aliphatic ester solvents such as ethyl acetate, n-butyl acetate, ethyl lactate, and n-butyl lactate; and aromatic ester solvents such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, isopropyl benzoate, propyl benzoate, and n-butyl benzoate; and other organic solvents used in the hole injection layer-forming composition and the hole transport layer-forming composition.

[0113] The solvent may be used alone or in any combination of two or more kinds in any ratio.

[0114] When the composition of the present invention contains a solvent, the content of the solvent contained in the composition of the present invention is preferably 10% by mass or more, more preferably 30% by mass or more, even more preferably 50% by mass or more, and particularly preferably 80% by mass or more, based on 100% by mass of the composition of the present invention. By being equal to or greater than the above lower limit, the flatness and uniformity of the formed layer can be improved.

[0115] [Photoelectric conversion element] The photoelectric conversion element of the present invention comprises a pair of electrodes having an upper electrode and a lower electrode, an active layer located between the pair of electrodes and containing an organic-inorganic hybrid semiconductor compound, and a hole transport layer located between the active layer and the upper electrode or the lower electrode, and contains the composition of the present invention. In another embodiment, the photoelectric conversion element of the present invention comprises a pair of electrodes having an upper electrode and a lower electrode, an active layer located between the pair of electrodes and containing an organic-inorganic hybrid semiconductor compound, and a hole transport layer located between the active layer and the upper electrode or the lower electrode, and the hole transport layer contains a crosslinked product of the composition of the present invention.

[0116] In the photoelectric conversion element 100 shown in FIG. 1 , a lower electrode 101, an active layer 103, and an upper electrode 105 are arranged in this order. As shown in FIG. 1 , a buffer layer 102 may be arranged between the lower electrode 101 and the active layer 103. The buffer layer 102 may be, for example, a hole transport layer. Furthermore, a buffer layer 104 may be arranged between the upper electrode 105 and the active layer 103. The buffer layer 104 may be, for example, an electron transport layer. Here, the buffer layer 102 may be an electron transport layer, and the buffer layer 104 may be a hole transport layer. As shown in FIG. 1 , the photoelectric conversion element 100 may have a substrate 106, and may also have other layers (not shown) such as an insulator layer and a work function tuning layer.

[0117] 1, the active layer 103 is a layer where photoelectric conversion takes place. When the photoelectric conversion element 100 receives light, the light is absorbed by the active layer 103, generating carriers, which are then extracted from the lower electrode 101 and the upper electrode 105.

[0118] In the photoelectric conversion element of the present invention, the active layer contains an organic-inorganic hybrid semiconductor compound, which is a compound in which an organic component and an inorganic component are combined at the molecular level or nano-level and which exhibits semiconductor properties.

[0119] The organic-inorganic hybrid semiconductor compound is preferably a compound having a perovskite structure (hereinafter, sometimes referred to as a perovskite semiconductor compound).

[0120] The perovskite structure of perovskite semiconductor compounds is perovskite (CaTiO ３ ; Perovskite) etc. ABX ３ This is a crystal structure represented by the composition ABX. ３ In the perovskite structure with the composition, six X atoms surround the B site ion. － are regularly surrounded to form a BX6 octahedron.

[0121] The perovskite semiconductor compound is not particularly limited, and can be selected from those listed in, for example, Galasso et al., Structure and Properties of Inorganic Solids, Chapter 7 - Perovskitetye and related structures. Also, for example, the perovskite semiconductor compound can be a compound represented by the general formula AMX ３ AMX expressed as ３ of the type or of the general formula A2MX ４ A represented by ２ MX ４ Here, M represents a divalent cation, A represents a monovalent cation, and X represents a monovalent anion.

[0122] The monovalent cation A is not particularly limited, and those described in the above-mentioned book by Galasso can be used. For example, cations containing elements of Groups 1 and 13 to 16 of the periodic table can be used. Among these, cesium ions, rubidium ions, potassium ions, optionally substituted ammonium ions, and optionally substituted phosphonium ions are preferred. Examples of optionally substituted ammonium ions include primary ammonium ions and secondary ammonium ions.

[0123] There are no particular limitations on the substituent. Examples of ammonium ions that may have a substituent include alkylammonium ions and arylammonium ions. In particular, monoalkylammonium ions that form a three-dimensional crystal structure are preferred to avoid steric hindrance. From the viewpoint of improving stability, alkylammonium ions substituted with one or more fluorine groups are preferred. As cation A, monoalkylammonium ions substituted with one or more fluorine groups are preferred. Two or more types of cations may be used in combination as cation A.

[0124] Examples of the monovalent cation A include a methylammonium ion, a methylammonium monofluoride ion, a methylammonium difluoride ion, a methylammonium trifluoride ion, an ethylammonium ion, an isopropylammonium ion, an n-propylammonium ion, an isobutylammonium ion, an n-butylammonium ion, a t-butylammonium ion, a dimethylammonium ion, a diethylammonium ion, a phenylammonium ion, a benzylammonium ion, a phenethylammonium ion, a guanidium ion, a formamidinium ion, an acetamidinium ion, and an imidazolium ion.

[0125] The divalent cation M is not particularly limited, but is preferably a divalent metal cation or semimetal cation. For example, a cation of a group 14 element of the periodic table can be mentioned. More specifically, a lead cation (Pb ２＋ ), tin cations (Sn ２＋ ), germanium cation (Ge ２＋ Two or more types of cations may be used in combination as the cation M. From the viewpoint of obtaining a stable photoelectric conversion element, it is particularly preferable to use a lead cation or two or more types of cations including a lead cation.

[0126] Examples of the monovalent anion X include a halide ion, acetate ion, nitrate ion, sulfate ion, borate ion, acetylacetonate ion, carbonate ion, citrate ion, sulfur ion, tellurium ion, thiocyanate ion, titanate ion, zirconate ion, 2,4-pentanedionate ion, and silicofluoride ion.

[0127] Examples of the anion X include a halide ion, or a combination of a halide ion and an anion other than a halide ion. Two or more types of anions may be used in combination as the anion X. The band gap of the active layer can be adjusted by the type and combination of the anions X. The anion X is preferably a halide ion such as a chloride ion, a bromide ion, or an iodide ion, since the band gap of the active layer tends to be appropriately narrowed, and more preferably a bromide ion or an iodide ion.

[0128] The perovskite semiconductor compound is preferably a halide-based organic-inorganic perovskite semiconductor compound. ３ NH ３ PbI ３ , C.H. ３ NH ３ PbBr ３ , C.H. ３ NH ３ PbCl ３ , C.H. ３ NH ３ SnI ３ , C.H. ３ NH ３ SnBr ３ , C.H. ３ NH ３ SnCl ３ , C.H. ３ NH ３ PbI （３－ｘ） Cl ｘ , C.H. ３ NH ３ PbI （３－ｘ） Br ｘ , C.H. ３ NH ３ PbBr （３－ｘ） Cl ｘ , C.H. ３NH ３ Pb （１－ｙ） Sn ｙ I ３ , C.H. ３ NH ３ Pb （１－ｙ） SnyBr ３ , C.H. ３ NH ３ Pb （１－ｙ） Sn ｙ Cl ３ , C.H. ３ NH ３ Pb （１－ｙ） Sn ｙ I （３－ｘ） Cl ｘ , C.H. ３ NH ３ Pb （１－ｙ） Sn ｙ I （３－ｘ） Br ｘ , and C.H. ３ NH ３ Pb （１－ｙ） Sn ｙ Br （３－ｘ） Cl ｘ ; In the above compounds, CH ３ NH ３ Instead of CFH ２ NH ３ , C.F. ２ HNH ３ , C.F. ３ NH ３ , N.H. ２ CH=NH ２ or a compound using Cs; or a mixture thereof. x is an arbitrary value of 0 or more and 3 or less, and y is an arbitrary value of 0 or more and 1 or less.

[0129] The active layer may contain two or more organic-inorganic hybrid semiconductor compounds. For example, the active layer may contain two or more organic-inorganic hybrid semiconductor compounds that are different in at least one of cation A, cation B, and anion X. The active layer may be a single layer containing different materials, or may have a laminate structure formed of multiple layers having different components.

[0130] The amount of the organic-inorganic hybrid semiconductor compound contained in the active layer is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, relative to the total mass of the active layer, so as to obtain good semiconductor characteristics. The upper limit of the amount of the organic-inorganic hybrid semiconductor compound contained in the active layer may be 100% by mass. The active layer may contain additives other than the organic-inorganic hybrid semiconductor compound contained in the active layer. Examples of additives include inorganic compounds such as inorganic salts such as halides, oxides, sulfides, sulfates, nitrates, and ammonium salts, and organic compounds.

[0131] There are no particular limitations on the thickness of the active layer. For example, it is preferably 10 nm or more, more preferably 50 nm or more, even more preferably 100 nm or more, particularly preferably 150 nm or more, particularly preferably 200 nm or more, preferably 1500 nm or less, more preferably 1200 nm or less, and even more preferably 800 nm or less. If it is equal to or greater than the above lower limit, more light is likely to be absorbed. If it is equal to or less than the above upper limit, the series resistance is reduced and the charge extraction efficiency is likely to be increased. The above upper and lower limits can be arbitrarily combined. For example, it may be 10 to 1500 nm, 50 to 1500 nm, 100 to 1200 nm, 150 to 1200 nm, or 200 to 800 nm.

[0132] The method for forming the active layer is not particularly limited, and the active layer can be formed by a known method. Examples include a coating method and a vapor deposition method (or a co-evaporation method). The coating method is preferred because it allows the active layer to be formed easily. For example, a method can be used in which a coating liquid containing an organic-inorganic hybrid semiconductor compound or a precursor thereof is applied, and then heated and dried as necessary to form the active layer. Furthermore, after applying the coating liquid, the organic-inorganic hybrid semiconductor compound can also be precipitated by further applying a solvent in which the organic-inorganic hybrid semiconductor compound has low solubility.

[0133] The organic-inorganic hybrid semiconductor compound precursor refers to a compound that becomes an organic-inorganic hybrid semiconductor compound after being applied as a coating liquid. For example, an organic-inorganic hybrid semiconductor compound precursor that becomes an organic-inorganic hybrid semiconductor compound by heating can be used.

[0134] For example, a compound represented by the general formula AX and a compound represented by the general formula MX ２ and a solvent, and the mixture is heated and stirred to prepare a coating solution. This coating solution is then applied and dried by heating, thereby obtaining a compound represented by the general formula AMX ３ It is possible to prepare an active layer containing a perovskite semiconductor compound represented by the formula (1). The solvent is not particularly limited as long as it dissolves the organic-inorganic hybrid semiconductor compound and optional additives, and examples thereof include organic solvents such as N,N-dimethylformamide.

[0135] General formula MX ２ and a solvent, and the mixture is heated and stirred to obtain a coating liquid, and then a coating liquid obtained by mixing a compound represented by the general formula AX and a solvent is applied to the coating liquid, thereby obtaining a coating liquid of the general formula AMX ３ Alternatively, an active layer containing a perovskite semiconductor compound represented by the following formula may be prepared.

[0136] The method for applying the coating liquid is not limited, and examples thereof include spin coating, inkjet coating, doctor blade coating, drop casting, reverse roll coating, gravure coating, kiss coating, roll brush coating, spray coating, air knife coating, wire barber coating, pipe doctor coating, impregnation / coating, and curtain coating.

[0137] The active layer of the photoelectric conversion element may contain an organic-inorganic hybrid semiconductor compound other than a perovskite semiconductor compound, such as an organic alkoxide-coordinated metal oxide or an organic molecule-coordinated transition metal complex.

[0138] 1, the buffer layer is a layer located between the active layer 103 and at least one of the pair of electrodes 101, 105. The buffer layer can be used, for example, to improve the efficiency of carrier movement from the active layer 103 to the lower electrode 101 or the upper electrode 105. The photoelectric conversion element preferably has a hole transport layer or an electron transport layer as the buffer layer, and more preferably has a hole transport layer.

[0139] (Hole Transport Layer) One embodiment of the hole transport layer in the photoelectric conversion element of the present invention contains a crosslinked product of the composition of the present invention.

[0140] The content of the crosslinked product of the composition of the present invention in the hole transport layer is preferably 40% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more, based on the total mass (100% by mass) of the hole transport layer, in terms of adhesion to the active layer containing the organic-inorganic hybrid semiconductor compound and high hole transport properties. Here, the upper limit is 100% by mass. Note that, when an electron-accepting compound is added to the hole transport layer to increase carrier mobility, the content of the crosslinked product of the composition of the present invention in the hole transport layer is the total amount including the electron-accepting compound. The above upper and lower limits can be arbitrarily combined. For example, the content may be 40 to 100% by mass, 50 to 100% by mass, or 60 to 100% by mass.

[0141] The hole transport layer may contain a semiconductor compound other than the crosslinked product of the composition of the present invention, as long as the effects of the present invention are achieved. As the other semiconductor compound, a conventionally known semiconductor compound can be used.

[0142] As other organic semiconductor compounds, various low molecular weight compounds and high molecular weight compounds are known.

[0143] Examples of low molecular weight organic semiconductor compounds include polycyclic aromatic compounds. Examples include acene compounds such as tetracene and pentacene, oligothiophene compounds, phthalocyanine compounds, perylene compounds, rubrene compounds, arylamine compounds such as triarylamine compounds, and carbazole compounds. Examples of high molecular weight organic semiconductor compounds include conjugated polymers such as polythiophene-based polymers, polyacetylene-based polymers, polyaniline-based polymers, polyphenylene-based polymers, polyphenylenevinylene-based polymers, polyfluorene-based polymers, and polypyrrole-based polymers, and arylamine polymers other than the charge transport polymers.

[0144] When forming a hole transport layer, it is preferable to use an electron-accepting compound in addition to the charge-transporting polymer (α) of the present invention and other semiconductor compounds, since the use of the electron-accepting compound can improve the conductivity of the layer.

[0145] The electron-accepting compound is preferably a compound having oxidizing power and the ability to accept one electron from the charge-transporting polymer of the present invention. More specifically, a compound having an electron affinity of 4.0 eV or more is preferred, and a compound having an electron affinity of 5.0 eV or more is more preferred.

[0146] Examples of the electron-accepting compound include triarylboron compounds, metal halides, Lewis acids, organic acids, onium salts, salts of arylamines and metal halides, and salts of arylamines and Lewis acids. Two or more types of electron-accepting compounds may be used in combination.

[0147] Examples of such compounds include onium salts substituted with organic groups, such as 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate and triphenylsulfonium tetrafluoroborate (WO 2005 / 089024 and WO 2017 / 164268); high-valent inorganic compounds, such as iron(III) chloride (JP 11-251067 A) and ammonium peroxodisulfate; cyano compounds, such as tetracyanoethylene; aromatic boron compounds, such as tris(pentafluorophenyl)borane (JP 2003-31365 A); fullerene derivatives; and iodine.

[0148] The electron-accepting compound preferably undergoes a charge-transfer reaction with at least one of the organic semiconductor compounds before or after the formation of the hole-transporting layer. As the electron-accepting compound, a hypervalent iodine compound is preferred because it has excellent solubility and easily generates an electron-accepting active site that functions as an oxidizing agent upon heating or the like.

[0149] It is known that hypervalent iodine compounds exhibit electron-accepting properties (i.e., function as oxidizing agents). A hypervalent iodine compound is a compound containing hypervalent iodine, and is defined as a compound containing iodine with an oxidation number of three or more. For example, the electron-accepting compound is preferably an iodine(III) compound or an iodine(V) compound.

[0150] Examples of iodine(V) compounds containing pentavalent iodine include periodinane compounds such as Dess-Martin periodinane, and examples of iodine(III) compounds containing trivalent iodine include compounds having an oxidized iodobenzene structure such as (diacetoxyiodo)benzene, and diaryliodonium salts.

[0151] The electron-accepting compound is preferably an organic compound containing trivalent iodine, and more preferably a diaryliodonium salt, because it exhibits good electron-accepting properties and is less likely to undergo a reverse reaction if the molecule is destroyed during the oxidation process.

[0152] Diaryliodonium salts are compounds represented by the formula [Ar-I ＋ -Ar]X－ Here, each of the two Ar's represents an aromatic group. The aromatic group is not particularly limited, and examples thereof include aromatic hydrocarbon groups such as those exemplified in the aromatic hydrocarbon group P1 and aromatic heterocyclic groups such as those exemplified in the aromatic heterocyclic group P2. X － represents any anion. － Examples of the cations include halide ions, trifluoroacetate ions, tetrafluoroborate ions, and tetrakis(pentafluorophenyl)borate ions.

[0153] X has high solubility and the reaction for producing the coating solution can proceed smoothly. － is preferably an anion having a fluorine atom. In terms of thermal and chemical stability and high solubility in organic solvents, a tetraarylborate ion represented by formula (4) is particularly preferred.

[0154] The ionization potential of the hole transport layer is preferably within a specific range, since it provides good matching with the holes generated in the active layer and makes it easy to suppress energy loss. For example, it is preferably -5.8 eV or more, more preferably -5.75 eV or more, and even more preferably -5.70 eV or more. On the other hand, the ionization potential of the hole transport layer is preferably -5.2 eV or less, more preferably -5.4 eV or less, even more preferably -5.45 eV or less, and particularly preferably -5.50 eV or less. It is particularly preferable that the ionization potential of the hole transport layer is -5.70 eV or more and -5.50 eV or less.

[0155] As described above, the ionization potential of the hole transport layer can be adjusted by using a charge transport polymer. A more detailed method for adjusting the ionization potential to the desired range is, for example, controlling the electronic state of the compound by appropriately arranging the type of aromatic group forming the main chain and the type and position of the substituent in the charge transport polymer (α). Another example is adjusting the electronic state of the compound contained in the hole transport layer by using an electron-accepting compound, which will be described later, in combination with the hole transport layer. The electronic state of the compound can be adjusted by oxidizing all or part of the compound, or by reducing all or part of the compound.

[0156] The thickness of the hole transport layer is preferably 20 nm or more, more preferably 40 nm or more, even more preferably 60 nm or more, and preferably 1000 nm or less, more preferably 750 nm or less, and even more preferably 500 nm or less. If the thickness is equal to or greater than the above-mentioned lower limit, when the active layer located between the upper and lower electrodes has high charge transport capability, current leakage due to the formation of a conduction path between the upper and lower electrodes and the active layer is unlikely to occur. If the thickness is equal to or less than the above-mentioned upper limit, resistance in charge transport by the hole transport layer is unlikely to occur, and costs can be reduced by saving the amount of compound contained in the hole transport layer. The above upper and lower limits can be arbitrarily combined. For example, the thickness may be 20 to 1000 nm, 40 to 750 nm, or 60 to 500 nm.

[0157] (Electrode) The electrode has the function of collecting holes and electrons generated by light absorption in the active layer. When the photoelectric conversion element has a substrate or is provided on a substrate, the electrode closer to the substrate can usually be called the lower electrode, and the electrode farther from the substrate can be called the upper electrode. In addition, a transparent electrode can also be called the lower electrode, and an electrode with lower transparency than the lower electrode can also be called the upper electrode.

[0158] The photoelectric conversion element 100 of the present invention shown in Figure 1 has a lower electrode 101 and an upper electrode 105. The pair of electrodes can be an anode suitable for collecting holes and a cathode suitable for collecting electrons. In this case, the photoelectric conversion element 100 may have a forward configuration in which the lower electrode 101 is the anode and the upper electrode 105 is the cathode, or may have an inverted configuration in which the lower electrode 101 is the cathode and the upper electrode 105 is the anode.

[0159] Either one of the pair of electrodes may be light-transmitting, or both may be light-transmitting. "Light-transmitting" means that the transmittance of normal sunlight (wavelength 350 to 700 nm) is 40% or more. The sunlight transmittance of the electrode is preferably high, since more light passes through the transparent electrode and reaches the active layer, and is particularly preferably 70% or more.

[0160] The sunlight transmittance can be measured using a spectrophotometer (e.g., Hitachi High-Tech U-4100). There are no particular limitations on the components and manufacturing methods of the lower electrode 101 and upper electrode 105, or the anode and cathode, and known techniques can be used. For example, components and manufacturing methods described in known publications such as International Publication No. 2013 / 171517, International Publication No. 2013 / 180230, and Japanese Patent Application Laid-Open No. 2012-191194 can be used.

[0161] (Electron Transport Layer) The photoelectric conversion element may have an electron transport layer. As a material for the electron transport layer, any material capable of improving the efficiency of extracting electrons from the active layer to the cathode can be used. Examples of such a material include inorganic compounds, organic compounds, and perovskite semiconductor compounds described in known documents such as WO 2013 / 171517, WO 2013 / 180230, and JP 2012-191194 A.

[0162] Examples of inorganic compounds include salts of alkali metals such as lithium, sodium, potassium, and cesium, and metal oxides such as zinc oxide, titanium oxide, aluminum oxide, and indium oxide. Examples of organic compounds include bathocuproine (BCP), bathophenanthrene (Bphen), (8-hydroxyquinolinato)aluminum (Alq3), boron compounds, oxadiazole compounds, benzimidazole compounds, naphthalenetetracarboxylic anhydride (NTCDA), perylenetetracarboxylic anhydride (PTCDA), fullerene compounds, and phosphine compounds having a double bond with an element of Group 16 of the periodic table, such as phosphine oxide compounds and phosphine sulfide compounds.

[0163] When the photoelectric conversion element includes an electron transport layer, its thickness is preferably 1 nm or more, more preferably 5 nm or more, even more preferably 10 nm or more, and preferably 200 nm or less, more preferably 150 nm or less, and even more preferably 100 nm or less. If the thickness is equal to or greater than the above-mentioned lower limit, when the active layer located between the upper and lower electrodes has high charge transport capability, current leakage due to the formation of a conductive path between the upper and lower electrodes and the active layer is unlikely to occur, the influence of the unevenness of the lower electrode can be compensated for, and the wettability of the active layer is easily controlled. If the thickness is equal to or less than the above-mentioned upper limit, resistance in charge transport by the electron transport layer is unlikely to occur, and costs can be reduced by saving the amount of compound contained in the electron transport layer. The above upper and lower limits can be arbitrarily combined. For example, it may be 1 to 200 nm, 5 to 150 nm, or 10 to 100 nm.

[0164] (Substrate) The photoelectric conversion element may have a substrate. In FIG. 1, the photoelectric conversion element 100 has a substrate 106 that serves as a support, but the photoelectric conversion element according to the present invention may not have the substrate 106. When a substrate is used, the material of the substrate 106 is not particularly limited as long as it does not significantly impair the effects of the present invention. For example, materials described in publicly known documents such as WO 2013 / 171517, WO 2013 / 180230, and JP 2012-191194 A can be used.

[0165] (Method for Manufacturing Photoelectric Conversion Element) The method for manufacturing the photoelectric conversion element of the present invention is not particularly limited, and any known method for manufacturing a photoelectric conversion element using a perovskite semiconductor compound can be applied.

[0166] For example, a hole transport layer can be formed using the composition of the present invention by a wet film formation method such as a spin coating method or an ink jet method. An electron transport layer can also be formed by a similar coating method. These buffer layers can also be formed by a dry film formation method such as a vacuum deposition method.

[0167] However, the hole transport layer is preferably formed by a coating method, and more preferably by coating the composition of the present invention.

[0168] 1, the photoelectric conversion element 100 can be manufactured by stacking the layers that make up the photoelectric conversion element 100. For example, known methods such as a sheet-to-sheet method or a roll-to-roll method can be applied.

[0169] The roll-to-roll method is a method in which a rolled flexible substrate is unwound and processed while being transported intermittently or continuously until it is wound up by a take-up roll. The roll-to-roll method makes it possible to process long substrates on the order of kilometers in length in one go, making it more suitable for mass production than the sheet-to-sheet method.

[0170] The size of the roll that can be used in the roll-to-roll method is not particularly limited as long as it can be handled by a roll-to-roll manufacturing device, but the outer diameter is preferably 5 m or less, more preferably 3 m or less, and even more preferably 1 m or less. On the other hand, it is preferably 10 cm or more, more preferably 20 cm or more, and even more preferably 30 cm or more. The outer diameter of the roll core is preferably 4 m or less, more preferably 3 m or less, and even more preferably 0.5 m or less. On the other hand, it is preferably 1 cm or more, more preferably 3 cm or more, even more preferably 5 cm or more, particularly preferably 10 cm or more, and most preferably 20 cm or more.

[0171] By having the outer diameter of the roll be within the above range, the roll is easy to handle, and the layers formed in each step are less likely to be damaged by bending stress. The roll width is preferably 5 cm or more, more preferably 10 cm or more, and even more preferably 20 cm or more. On the other hand, it is preferably 5 m or less, more preferably 3 m or less, and even more preferably 2 m or less. A large width makes the roll easy to handle, and increases the degree of freedom in the size of the photoelectric conversion element.

[0172] When manufacturing the photoelectric conversion element 100, the photoelectric conversion element 100 may be heated after the upper electrode 105 is laminated (this heating step may be referred to as an annealing treatment step).

[0173] The heating temperature in the annealing treatment step is preferably 50°C or higher, more preferably 80°C or higher, and preferably 300°C or lower, more preferably 280°C or lower, and even more preferably 250°C or lower. If the temperature is above the lower limit, the adhesion between the layers of the photoelectric conversion element 100, for example, between the buffer layer 102 and the lower electrode 101, the buffer layer 102 and the active layer 103, etc., is enhanced, thereby improving the thermal stability and durability of the photoelectric conversion element. If the temperature is below the upper limit, the organic compound contained in the photoelectric conversion element 100 is less likely to be thermally decomposed. The upper and lower limits can be arbitrarily combined. For example, the temperature may be 50 to 300°C, 50 to 280°C, or 80 to 250°C. In the annealing treatment step, stepwise heating using different temperatures within the above temperature range may be performed.

[0174] In the annealing treatment step, the heating time within the above-described preferred temperature range is preferably 1 minute or more, more preferably 3 minutes or more, in order to improve adhesion while suppressing thermal decomposition. Also, the heating time is preferably 180 minutes or less, more preferably 60 minutes or less. The above upper and lower limits can be arbitrarily combined. For example, the heating time may be 1 to 180 minutes, or 3 to 60 minutes.

[0175] The annealing process is preferably terminated when the photoelectric conversion characteristics of the solar cell, such as the open-circuit voltage, short-circuit current, and fill factor, reach certain values. The annealing process is preferably carried out under normal pressure in an inert gas atmosphere to prevent thermal oxidation of the constituent materials. The heating method may involve placing the photoelectric conversion element on a heat source such as a hot plate, or placing the photoelectric conversion element in a heated atmosphere such as an oven. Heating may be carried out batchwise or continuously.

[0176] (Photoelectric Conversion Characteristics) The photoelectric conversion characteristics of the photoelectric conversion element 100 can be determined as follows. The photoelectric conversion element 100 is irradiated with light of an appropriate spectrum at a certain irradiation intensity, and the current-voltage characteristics are measured. From the obtained current-voltage curve, photoelectric conversion characteristics such as photoelectric conversion efficiency (PCE), short-circuit current density (Jsc), open circuit voltage (Voc), fill factor (FF), series resistance, and shunt resistance can be determined.

[0177] Here, the short-circuit current density (Jsc) is the current density when the voltage value is 0 (V), and the open-circuit voltage (Voc) is the current density when the current value is 0 (mA / cm ２ ) is the voltage value when the fill factor (FF) is a factor that represents the internal resistance.

[0178] The fill factor (FF) is expressed by the following formula, where Pmax is the maximum output: FF = Pmax / (Voc x Jsc)

[0179] The photoelectric conversion efficiency (PCE) is given by the following formula, where Pin is the incident energy: PCE = (Pmax / Pin) x 100 = (Voc x Jsc x FF / Pin) x 100

[0180] The incident energy Pin is, for example, 100 mW / cm for sunlight with an intensity of AM 1.5 G. ２ When white LED light with a color temperature of 5000K is irradiated and the illuminance on the light receiving surface is 200 lux, the ２ The color temperature of 5000K is defined by the JIS Z8725:2015 standard.

[0181] [Example of Use] A thin-film solar cell 14 shown in FIG. 2 includes, in this order, a weather-resistant protective film 1, an ultraviolet-cutting film 2, a gas barrier film 3, a getter material film 4, a sealing material 5, a solar cell element 6 having a photoelectric conversion element (not shown), a sealing material 7, a getter material film 8, a gas barrier film 9, and a back sheet 10.

[0182] The thin-film solar cell 14 is configured so that light is irradiated from the side where the protective film 1 is formed (the lower side in FIG. 2 ), and the solar cell element 6 generates electricity. The thin-film solar cell 14 does not need to have all of these components, and necessary components can be selected arbitrarily.

[0183] The thin-film solar cell 14 may be used alone, or a plurality of thin-film solar cells 14 may be connected together, or may be used as a component of a solar cell module in combination with other components. For example, as shown in Fig. 3, a solar cell module 13 having thin-film solar cells 14 on a substrate 12 may be fabricated, and this solar cell module 13 may be installed at the location of use.

[0184] The selection of each of the above-mentioned components and their manufacturing methods can be achieved by applying well-known techniques, such as those described in known documents such as International Publication No. 2013 / 171517, International Publication No. 2013 / 180230, and Japanese Patent Application Laid-Open No. 2012-191194.

[0185] There are no limitations on the applications of the photoelectric conversion element and the solar cell and solar cell module including the same, and examples thereof include solar cells for building materials, solar cells for automobiles, solar cells for interior decoration, solar cells for railways, solar cells for ships, solar cells for airplanes, solar cells for spacecraft, solar cells for home appliances, solar cells for mobile phones, and solar cells for toys.

[0186] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following description.

[0187] (Synthesis of Compound 1)

[0188]

[0189] A flask was charged with 13.2 g (66.41 mmol) of 4'-bromoacetophenone, 75.0 g (796.94 mmol) of phenol, and 85 mL of acetic acid under a nitrogen stream and stirred at room temperature. 240 mL of hydrochloric acid (12 M) was added, and the mixture was heated to reflux at 90°C for 24 hours. After the reaction, the reaction solution was poured into hot water, and the insoluble matter was dissolved in ethyl acetate. The liquid was then separated, and the organic layer was dried over magnesium sulfate and concentrated. Compound 1 (11.73 g) was obtained by further purification using silica gel column chromatography (hexane:ethyl acetate = 4:1).

[0190] (Synthesis of Compound 3)

[0191]

[0192] Compound 1 (4.67 g; 12.65 mmol), compound 2 (3.9 g; 13.92 mmol), and 80 mL of 1,2-dimethoxyethane were placed in a flask under a nitrogen stream and stirred at room temperature. 22 mL of 2 M aqueous potassium carbonate solution was added, and nitrogen was bubbled through at room temperature for 30 minutes. Tetrakis(triphenylphosphine)palladium (0.29 g; 0.25 mmol) was then added, and the mixture was heated to reflux under nitrogen for 4 hours. After cooling, the mixture was extracted with ethyl acetate, separated, and the organic layer was dried over magnesium sulfate and concentrated. The mixture was further purified by silica gel column chromatography (hexane:ethyl acetate=3:1) to obtain compound 3 (5.5 g).

[0193] (Synthesis of Compound 4)

[0194]

[0195] Compound 3 (5.5 g; 12.43 mmol), methylene chloride (90 ml), and triethylamine (6.3 g; 62.15 mmol) were dissolved at -5°C, and trifluoromethanesulfonic anhydride (10.5 g; 37.3 mmol) dissolved in 17 ml of methylene chloride was slowly added dropwise, and the mixture was stirred for 4 hours. The reaction solution was poured into ice water, extracted with methylene chloride, separated, dried over magnesium sulfate, and concentrated. Compound 4 (7.3 g) was obtained by further purification using silica gel column chromatography (hexane:methylene chloride=3:1).

[0196] (Synthesis of Compound 5)

[0197]

[0198] Under a nitrogen stream, 100 ml of dimethyl sulfoxide, compound 4 (7.1 g; 10.05 mmol), bis(pinacolato)diboron (6.1 g; 24.11 mmol), and potassium acetate (5.9 g; 60.3 mmol) were placed in a 300 ml flask and stirred at 60°C for 30 minutes. Then, 1,1'-bis(diphenylphosphino)ferrocene-palladium(II) dichloride-dichloromethane [PdCl ２ (dppf)CH ２ Cl ２ ] (0.41 g; 0.50 mmol) was added and the mixture was reacted at 85° C. for 3.5 hours. The reaction solution was filtered under reduced pressure, toluene was added to the filtrate, the layers were separated, and the organic layer was dried over anhydrous magnesium sulfate. After concentration, the precipitate was washed with methanol to obtain compound 5 (colorless solid; 3.6 g).

[0199] (Synthesis of Compound 6)

[0200]

[0201] Under a nitrogen stream, 120 ml of toluene, 60 ml of ethanol, compound 5 (3.6 g; 5.43 mmol), 1-bromo-4-iodobenzene (3.38 g; 11.96 mmol), and an aqueous potassium phosphate solution (2 M, 18 ml) were placed in a 500 ml flask and heated with stirring for 30 minutes. ３ ) ４ ] (0.28 g; 0.24 mmol) was added and the mixture was refluxed for 4.5 hours. After cooling, water was added to the reaction mixture, which was then extracted with toluene and treated with anhydrous magnesium sulfate and activated clay. The mixture was purified by adsorption silica gel column chromatography (developing solvent: n-hexane:toluene=4:1) to obtain Compound 6 (colorless solid; 2.1 g).

[0202] (Synthesis of Compound 7)

[0203]

[0204] Under a nitrogen stream, 180 ml of toluene, 2,7-dibromo-9,9-dimethylfluorene (8.0 g; 22.72 mmol), 4-methylaniline (5.0 g; 46.36 mmol), and sodium tert-butoxide (15.3 g; 159.06 mmol) were placed in a 500 ml flask, and the mixture was bubbled with nitrogen for 10 minutes and stirred for 30 minutes. Subsequently, a catalyst obtained by adding 1,1'-bis(diphenylphosphino)ferrocene (0.61 g, 1.09 mmol) to a 20.0 ml toluene solution of tris(dibenzylideneacetone)dipalladium complex chloroform (0.282 g, 0.273 mmol) and heating to 60°C was added, and the mixture was reacted at 100°C for 2.5 hours. Thereafter, 1-bromo-4-iodobenzene (15.4 g; 54.54 mmol) was further added to the reaction solution, and after allowing it to cool, water was added to the reaction solution and the reaction was carried out at 123°C for 4.5 hours. Inorganic salts precipitated at room temperature were removed by filtration under reduced pressure. The filtrate was purified by adsorption silica gel column chromatography (developing solvent: n-hexane:methylene chloride=9:1) to obtain Compound 7 (colorless solid; 11.3 g).

[0205] Compound 8 can be produced with reference to JP 2021-502161 A.

[0206] (Synthesis of Polymer 1)

[0207]

[0208] 4,4'-Dibromobiphenyl (2.5 g, 8.01 mmol), 2,4,6-trimethylaniline (2.17 g, 16.02 mmol), sodium tert-butoxide (5.94 g, 61.8 mmol), and toluene (50.0 g, 58 ml) were charged, the system was thoroughly purged with nitrogen, and the mixture was heated to 60°C (Solution A1). Separately, [4-(N,N-dimethylamino)phenyl]di-tert-butylphosphine (0.34 g, 1.3 mmol) was added to a solution of tris(dibenzylideneacetone)dipalladium complex (0.147 g, 0.16 mmol) in 22.0 ml of toluene, and the mixture was heated to 60°C (Solution B1).

[0209] Solution B1 was added to Solution A1 in a nitrogen stream, and the mixture was heated under reflux for 1.0 hour. After confirming that 4,4'-dibromobiphenyl had disappeared, Compound 6 (1.16 g, 1.60 mmol) was added. After 1 hour of reaction, 4,4'-dibromobiphenyl (1.61 g, 5.14 mmol) was added. After heating under reflux for 1 hour, bromobenzene (1.99 g, 12.7 mmol) was added, and the mixture was heated under reflux for 1 hour. The reaction solution was allowed to cool and then added dropwise to 195 ml of ethanol solution to obtain an end-capped crude polymer. This end-capped crude polymer was dissolved in toluene, acetone was added, and the precipitated polymer was filtered off. The obtained polymer was dissolved in toluene, washed with dilute hydrochloric acid, and reprecipitated in ammonia-containing ethanol. The filtered polymer was purified by column chromatography to obtain the target product, Polymer 1 (2.8 g). The molecular weight and other properties of the obtained Polymer 1 were as follows:

[0210] Weight average molecular weight (Mw) = 11315, number average molecular weight (Mn) = 7028, dispersity (Mw / Mn) = 1.61

[0211] (Synthesis of Polymer 2)

[0212]

[0213] 4,4'-Dibromobiphenyl (2.5 g, 8.01 mmol), 2,4,6-trimethylaniline (2.17 g, 16.02 mmol), sodium tert-butoxide (5.94 g, 61.8 mmol), and toluene (50.0 mL, 58 mL) were charged, the system was thoroughly purged with nitrogen, and the mixture was heated to 60°C (Solution A2). Separately, to a solution of tris(dibenzylideneacetone)dipalladium complex (0.147 g, 0.16 mmol) in 22.0 mL of toluene, [4-(N,N-dimethylamino)phenyl]di-tert-butylphosphine (0.34 g, 1.3 mmol) was added, and the mixture was heated to 60°C (Solution B2).

[0214] Solution B2 was added to solution A2 in a nitrogen stream, and the mixture was heated under reflux for 1.0 hour. After confirming that 4,4'-dibromobiphenyl had disappeared, compound 6 (1.50 g, 2.1 mmol) was added. After 1 hour of reaction, compound 8 (2.303 g, 4.33 mmol) was added. After heating under reflux for 1 hour, bromobenzene (2.52 g, 16.0 mmol) was added, and the mixture was heated under reflux for 1 hour. The reaction solution was allowed to cool and added dropwise to 195 ml of ethanol solution to obtain an end-capped crude polymer.

[0215] The end-capped crude polymer was dissolved in toluene, acetone was added, and the precipitated polymer was filtered off. The resulting polymer was dissolved in toluene, washed with dilute hydrochloric acid, and reprecipitated in ammonia-containing ethanol. The filtered polymer was purified by column chromatography to obtain the target product, Polymer 2 (3.3 g). The molecular weight and other properties of the resulting Polymer 2 were as follows:

[0216] Weight average molecular weight (Mw) = 11878, number average molecular weight (Mn) = 7566, dispersity (Mw / Mn) = 1.57

[0217] (Synthesis of Polymer 3)

[0218]

[0219] Compound 7 (6.12 g, 8.57 mmol), 2,4,6-trimethylaniline (1.04 g, 7.69 mmol), compound 8 (0.88 g, 2.21 mmol), sodium tert-butoxide (3.67 g, 38.19 mmol), and toluene (36 ml) were charged, the system was thoroughly purged with nitrogen, and the mixture was heated to 60° C. (Solution A3). Separately, to a solution of tris(dibenzylideneacetone)dipalladium complex (0.091 g, 0.1 mmol) in 22.0 ml of toluene, [4-(N,N-dimethylamino)phenyl]di-tert-butylphosphine (0.21 g, 0.79 mmol) was added, and the mixture was heated to 60° C. (Solution B3).

[0220] Solution B3 was added to Solution A3 under a nitrogen atmosphere, and the mixture was heated under reflux for 2.0 hours. Bromobenzene (2.1 g, 13.4 mmol) was then added, and the mixture was heated under reflux for 1 hour. The reaction mixture was allowed to cool, and 16 ml of toluene was added. The mixture was then added dropwise to 275 ml of ethanol to obtain an end-capped crude polymer.

[0221] The end-capped crude polymer was dissolved in toluene, acetone was added, and the precipitated polymer was filtered off. The resulting polymer was dissolved in toluene and purified by column chromatography to obtain the target polymer 3 (2.8 g). The molecular weight and other properties of the resulting polymer 3 were as follows:

[0222] Weight average molecular weight (Mw) = 12208, number average molecular weight (Mn) = 9249, dispersity (Mw / Mn) = 1.32

[0223] (Preparation of Coating Liquid 1 for Hole Transport Layer) Solution (A) was prepared by adding anisole (1 mL) to polymer 1 (22 mg). Separately, solution (B) was prepared by adding anisole (1 mL) to 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate (TPFB; manufactured by TCI; 22 mg). 0.1 mL of solution (B) was added dropwise to solution (A), and the resulting mixture was heated and stirred at 130°C for 1 hour. Thereafter, the mixture was filtered through a polytetrafluoroethylene (PTFE) filter (pore size 0.45 μm) to prepare Coating Liquid 1 for Hole Transport Layer.

[0224] (Preparation of hole transport coating liquid 2) Anisole (1 mL) was added to polymer 2 (22 mg) to prepare solution (C). 0.1 mL of solution (B) prepared in "Preparation of hole transport layer coating liquid 1" was added dropwise to solution (C), and the resulting mixture was heated and stirred at 130°C for 1 hour. Thereafter, the mixture was filtered through a PTFE filter (pore size 0.45 µm) to prepare hole transport layer coating liquid 2.

[0225] (Preparation of Hole Transport Coating Liquid 3) Anisole (1 mL) was added to poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (22 mg) to prepare a solution (D). 0.1 mL of the solution (B) prepared in "Preparation of Hole Transport Layer Coating Liquid 1" was mixed with the solution (D), and the resulting mixture was heated and stirred at 130°C for 1 hour. The mixture was then filtered through a PTFE filter (pore size 0.45 μm) to prepare a hole transport layer coating liquid 3.

[0226] (Preparation of Hole Transport Layer Coating Liquid 4) Anisole (1 mL) was added to the following compound (22 mg) to prepare a solution (E). 0.1 mL of the solution (B) prepared in "Preparation of Hole Transport Layer Coating Liquid 1" was added dropwise to the solution (E), and the resulting mixture was heated and stirred at 130°C for 1 hour. The mixture was then filtered through a PTFE filter (pore size 0.45 µm) to prepare a hole transport layer coating liquid 4.

[0227]

[0228] (Preparation of Coating Solution 5 for Hole Transport Layer) Anisole (1 mL) was added to Polymer 1 (20 mg), and the mixture was heated and stirred for 20 minutes at 130° C. Thereafter, the mixture was filtered through a PTFE filter (pore size: 0.45 μm) to prepare Coating Solution 5 for Hole Transport Layer.

[0229] (Preparation of Hole Transport Coating Liquid 6) Solution (F) was prepared by adding anisole (1 mL) to polymer 1 (24.2 mg). Separately, solution (G) was prepared by adding anisole (1 mL) to TPFB (24.2 mg). Furthermore, solution (H) was prepared by adding anisole (1 mL) to the following compound (11 mg). 0.1 mL of solution (G) was added dropwise to solution (F), and the resulting mixture was heated and stirred at 130°C for 1 hour. 0.11 mL of solution (H) was added to this solution, and the mixture was thoroughly mixed at room temperature. Thereafter, the mixture was filtered through a PTFE filter (pore size 0.45 µm) to prepare coating liquid 6 for hole transport layer.

[0230]

[0231] (Preparation of Hole Transport Coating Liquid 7) Anisole (1 mL) was added to Polymer 3 (24.2 mg) to prepare Solution (I). 0.1 mL of Solution (G) prepared in "Preparation of Hole Transport Layer Coating Liquid 6" was added dropwise to Solution (I), and the resulting mixture was heated and stirred at 130°C for 1 hour. 0.11 mL of Solution (H) prepared in "Preparation of Hole Transport Layer Coating Liquid 6" was added to this solution, and the mixture was thoroughly mixed at room temperature. Thereafter, the mixture was filtered through a PTFE filter (pore size 0.45 μm) to prepare Hole Transport Layer Coating Liquid 7.

[0232] (Preparation of Active Layer Coating Solution) Formamidine hydroiodide (FAI) (172 mg), methylamine hydrobromide (MABr) (22.2 mg), lead(II) iodide (507.1 mg), and lead(II) bromide (73.4 mg) were weighed into a vial so that the molar ratio was 1:0.2:1.1:0.2, and N,N-dimethylformamide (0.9 mL) was added. Then, DMSO (0.1 mL) was added to prepare solution (F). Separately, cesium iodide (CsI) (389.7 mg) was added to DMSO (1 mL) to prepare solution (G). Next, 41.7 μL of solution (G) was added dropwise to solution (F), and the resulting mixture was heated and stirred at 70 °C for 30 minutes. Thereafter, the active layer coating solution was prepared by filtering with a PTFE filter (pore size 0.45 μm).

[0233] (Preparation of Coating Solution for Electron Transport Layer) mixPCBM(C ６０ : C ７０ Chlorobenzene (3 mL) was added to 90 mg of a 75:25 mixture of ethylenediaminetetraacetic acid and propylene glycol ether (PEA) and propylene glycol ether (PEA) (95:25). The resulting solution was heated and stirred at 70° C. for 30 minutes, and then filtered through a PTFE filter (pore size: 0.45 μm) to prepare a coating solution for an electron transport layer.

[0234] (Preparation of Coating Solution for Interface Layer) An 80% ethoxylated solution of polyethyleneimine (manufactured by Sigma-Aldrich) was diluted with isopropyl alcohol to 0.02 wt % to prepare a coating solution for interface layer.

[0235] Example 1 A glass substrate having a patterned indium tin oxide (ITO) transparent conductive film was subjected to UV ozone treatment for 20 minutes, and then the hole transport coating solution 1 was spin-coated at 4000 rpm, followed by heat treatment at 230°C for 30 minutes to form a crosslinked hole transport layer of approximately 40 nm.

[0236] Next, the active layer coating solution was spin-coated onto the hole transport layer at 4000 rpm, and after about 10 seconds, chlorobenzene (200 μL) was further spin-coated to change the solvent composition in the coating solution film, thereby precipitating crystals of a perovskite composition. The active layer (perovskite crystal layer) was then formed by heating the film on a hot plate at 100° C. for 10 minutes to grow the crystals.

[0237] Next, the coating liquid for the electron transport layer was applied onto the active layer at 1000 rpm, and then the coating liquid for the interface layer was applied at 6000 rpm, followed by heating for 10 minutes at 100° C. Next, a silver film having a thickness of about 100 nm was deposited by a resistance heating vacuum deposition method using a patterning mask to form an electrode.

[0238] Finally, the glass substrate of the photoelectric conversion element was bonded to the glass substrate of the photoelectric conversion element with a sealing material (photocurable resin), thereby sealing the photoelectric conversion element.

[0239] Example 2 A photoelectric conversion element was produced under the same conditions as in Example 1, except that the hole transport coating liquid 2 was used.

[0240] Comparative Example 1 A photoelectric conversion element was produced under the same conditions as in Example 1, except that the hole transport coating liquid 3 was used.

[0241] Comparative Example 2 A photoelectric conversion element was produced under the same conditions as in Example 1, except that the hole transport coating liquid 4 was used.

[0242] Comparative Example 3 A photoelectric conversion element was produced under the same conditions as in Example 1, except that the hole transport coating liquid 5 was used and the heat treatment of the hole transport layer was performed at 100° C. for 10 minutes.

[0243] Example 3 An active layer was formed in the same manner as in Example 1, except that hole transport coating solution 6 was used. Next, an electron transport coating solution diluted 1.5 times with chlorobenzene was applied at 2000 rpm and heated at 100°C for 10 minutes. Fullerene was deposited thereon to a thickness of 25 nm, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) to a thickness of 8 nm, and silver to a thickness of 100 nm. Finally, sealing was performed in the same manner as in Comparative Example 3.

[0244] Example 4 A photoelectric conversion element was produced under the same conditions as in Example 3, except that the hole transport coating liquid 7 was used.

[0245] (Evaluation of Conductivity) A glass substrate equipped with comb-shaped patterned indium tin oxide (ITO) electrodes was subjected to UV ozone treatment for 20 minutes. Only a hole transport layer was formed on the substrate under the same conditions as for the photoelectric conversion element. The current-voltage characteristics and film thickness of this coating film were measured to calculate the conductivity (S / cm), which is shown in the table.

[0246] (Evaluation of Solvent Resistance) The coating film used in the conductivity evaluation was rubbed with a cloth soaked in N,N-dimethylformamide, and the change in the surface shape was visually confirmed. Those that showed no change in the surface state were given a grade A, and those that showed a change were given a grade B, and these are shown in the table.

[0247] (Wettability of Active Layer Coating Liquid) In the table, the samples in which a uniform perovskite film was formed in the device area by the method described in Example 1 above were marked with A, and the samples in which a photoelectric conversion device could not be produced due to repelling were marked with B.

[0248] (Evaluation of energy conversion efficiency) A mask with a 4 mm square opening was attached to the photoelectric conversion element obtained in each example, and the current-voltage characteristics between the ITO electrode and the upper electrode were measured. For the measurement, a source meter (manufactured by Keithley; Model 2400) was used, and the irradiation light source was an air mass (AM) of 1.5 G and an irradiance of 100 mW / cm. ２ A solar simulator was used. The voltage was swept from positive to negative, then swept back to positive, and measurements were taken three times in succession. The power conversion efficiency (PCE) at the third measurement, when the voltage was swept from positive to negative, is shown in the table.

[0249] (Evaluation of Durability) The photoelectric conversion elements obtained in each example were subjected to an air mass (AM) of 1.5 G and an irradiance of 100 mW / cm ２ The change in energy conversion efficiency when continuously irradiated with light was evaluated and shown in the table.

[0250]

[0251]

[0252] As shown in Table 1, it was confirmed that both Example 1 and Example 2 had good conductivity and solvent resistance of the hole transport layer and good wettability of the perovskite layer, and exhibited high photoelectric conversion characteristics. In Comparative Example 3, the conductivity of the hole transport layer was poor, and carriers generated by light could not be extracted, resulting in low PCE. In Comparative Example 2, the coating liquid for the active layer was repelled by the hole transport layer, making it impossible to form a perovskite layer. In Comparative Example 1, good characteristics were obtained immediately after the photoelectric conversion element was produced, but it was confirmed that rapid deterioration due to light irradiation occurred. It can be assumed that the hole transport layer was altered by the solvent in the coating liquid for the active layer, causing the interface state to become unstable.

[0253] As shown in Table 2, it was confirmed that Examples 3 and 4 also exhibited good photoelectric conversion characteristics.

[0254] According to the present invention, a composition that can be suitably applied to the formation of a hole transport layer even when a photoelectric conversion element having an active layer containing a perovskite semiconductor compound has an inverted structure can be provided. Also, the present invention can provide a charge transport polymer that can be suitably applied to the formation of a hole transport layer even when a photoelectric conversion element having an active layer containing a perovskite semiconductor compound has an inverted structure.

[0255] REFERENCE SIGNS LIST 1 Weather-resistant protective film 2 UV-cut film 3, 9 Gas barrier film 4, 8 Getter material film 5, 7 Sealant 6 Solar cell element 10 Back sheet 12 Substrate 13 Solar cell module 14 Thin-film solar cell 100 Photoelectric conversion element 101 Lower electrode 102 Buffer layer 103 Active layer 104 Buffer layer 105 Upper electrode 106 Substrate

Claims

1. A composition for forming a hole transport layer of a photoelectric conversion element, comprising a charge transport polymer (α) and a tetraarylborate ion, wherein the charge transport polymer (α) has a crosslinkable group and further has a chemical structure of the following formula (5) in its main chain, and the tetraarylborate ion is represented by the following formula (4). (In formula (5), R １ represents an alkyl group having 1 to 4 carbon atoms, and R ２ ~R ５ each independently represents a hydrogen atom; an alkyl group having 1 to 24 carbon atoms; an aryloxy group having 4 to 36 carbon atoms; an alkoxycarbonyl group having 2 to 24 carbon atoms; a dialkylamino group having 2 to 24 carbon atoms; an acyl group having 2 to 24 carbon atoms; a halogen atom; a haloalkyl group having 1 to 12 carbon atoms; an alkylthio group having 1 to 24 carbon atoms; an arylthio group having 4 to 36 carbon atoms; a siloxy group having 2 to 36 carbon atoms; a cyano group; an aromatic hydrocarbon group having 6 to 36 carbon atoms; or an aromatic heterocyclic group having 3 to 36 carbon atoms; ２ ~R ５ each group may be substituted with one or more groups selected from the group consisting of an alkyl group having 1 to 24 carbon atoms; an aryloxy group having 4 to 36 carbon atoms; an alkoxycarbonyl group having 2 to 24 carbon atoms; a dialkylamino group having 2 to 24 carbon atoms; an acyl group having 2 to 24 carbon atoms; a halogen atom; a haloalkyl group having 1 to 12 carbon atoms; an alkylthio group having 1 to 24 carbon atoms; an arylthio group having 4 to 36 carbon atoms; a siloxy group having 2 to 36 carbon atoms; a cyano group; an aromatic hydrocarbon group having 6 to 36 carbon atoms; and an aromatic heterocyclic group having 3 to 36 carbon atoms; ２ ~R ４ Two adjacent groups may be bonded to each other to form a ring. (In formula (4), Ar ３１ , Ar ３２ , Ar ３３ , and Ar ３４ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, ３１ , Ar ３２ , Ar ３３ , and Ar ３４ At least one of the groups has a fluorine atom or a fluorine-substituted alkyl group as a substituent.

2. A composition for forming a hole transport layer of a photoelectric conversion element, comprising a charge transport polymer (α) and a tetraarylborate ion, wherein the charge transport polymer (α) has a chemical structure represented by the following formula (5) in its main chain, and further has at least one group selected from the following group of crosslinkable groups T, and the tetraarylborate ion is represented by the following formula (4). (In formula (5), R １ represents an alkyl group having 1 to 4 carbon atoms, and R ２ ~R ５ each independently represents a hydrogen atom; an alkyl group having 1 to 24 carbon atoms; an aryloxy group having 4 to 36 carbon atoms; an alkoxycarbonyl group having 2 to 24 carbon atoms; a dialkylamino group having 2 to 24 carbon atoms; an acyl group having 2 to 24 carbon atoms; a halogen atom; a haloalkyl group having 1 to 12 carbon atoms; an alkylthio group having 1 to 24 carbon atoms; an arylthio group having 4 to 36 carbon atoms; a siloxy group having 2 to 36 carbon atoms; a cyano group; an aromatic hydrocarbon group having 6 to 36 carbon atoms; or an aromatic heterocyclic group having 3 to 36 carbon atoms; ２ ~R ５ each group may be substituted with one or more groups selected from the group consisting of an alkyl group having 1 to 24 carbon atoms; an aryloxy group having 4 to 36 carbon atoms; an alkoxycarbonyl group having 2 to 24 carbon atoms; a dialkylamino group having 2 to 24 carbon atoms; an acyl group having 2 to 24 carbon atoms; a halogen atom; a haloalkyl group having 1 to 12 carbon atoms; an alkylthio group having 1 to 24 carbon atoms; an arylthio group having 4 to 36 carbon atoms; a siloxy group having 2 to 36 carbon atoms; a cyano group; an aromatic hydrocarbon group having 6 to 36 carbon atoms; and an aromatic heterocyclic group having 3 to 36 carbon atoms; ２ ~R ４ Two adjacent groups may be bonded to each other to form a ring. (In formula (4), Ar ３１ , Ar ３２ , Ar ３３ , and Ar ３４ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, ３１ , Ar ３２ , Ar ３３ , and Ar ３４ At least one of the groups has a fluorine atom or a fluorine-substituted alkyl group as a substituent. (In the formula, R ２４ , R ２５ , and R ２６ each independently represents a hydrogen atom or an alkyl group, ２７ , R ２８ , and R ２９ each independently represents an alkyl group or an alkoxy group, Ar ２１ , and Ar ２２ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent; p represents an integer of 0 to 4; q represents an integer of 0 to 5; r represents an integer of 0 to 7; and * represents a bond.

3. The composition according to claim 1 or 2, wherein the charge transporting polymer (α) has a unit represented by the following formula (1), (2) or (3): (In formula (1), R １１ represents a hydrogen atom, an alkyl group having 1 to 24 carbon atoms which may have a substituent, an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, １１ represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent, １２ , Ar １３ , and Ar １４ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, １ represents a crosslinkable group. １１ At least one atom adjacent to the atom bonded to the nitrogen atom in the formula (I) is bonded to an alkyl group having 1 to 4 carbon atoms. (In formula (2), Ar １５ , Ar １６ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, １ represents a crosslinkable group. １５ At least one atom adjacent to the atom bonded to the nitrogen atom in the formula (I) is bonded to an alkyl group having 1 to 4 carbon atoms. (In formula (3), Ar １７ , Ar １８ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, １ represents a crosslinkable group. １７ At least one atom adjacent to the atom bonded to the nitrogen atom in the formula (I) is bonded to an alkyl group having 1 to 4 carbon atoms.

4. The composition according to claim 3, wherein the charge transporting polymer (α) has a unit represented by the following formula (1) or (3): (In formula (1), R １１ represents a hydrogen atom, an alkyl group having 1 to 24 carbon atoms which may have a substituent, an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, １１ represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent, １２ , Ar １３ , and Ar １４ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, １ represents a crosslinkable group. １１ At least one atom adjacent to the atom bonded to the nitrogen atom in the formula (I) is bonded to an alkyl group having 1 to 4 carbon atoms. (In formula (3), Ar １７ , Ar １８ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, １ represents a crosslinkable group. １７ At least one atom adjacent to the atom bonded to the nitrogen atom in the formula (I) is bonded to an alkyl group having 1 to 4 carbon atoms.

5. The composition according to claim 3, wherein the charge transporting polymer (α) has a unit represented by the following formula (1): (In formula (1), R １１ represents a hydrogen atom, an alkyl group having 1 to 24 carbon atoms which may have a substituent, an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, １１ represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent, １２ , Ar １３ , and Ar １４ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, １ represents a crosslinkable group. １１ At least one atom adjacent to the atom bonded to the nitrogen atom in the formula (I) is bonded to an alkyl group having 1 to 4 carbon atoms.

6. The composition according to claim 3, wherein the charge transporting polymer (α) has a unit represented by the following formula (2): (In formula (2), Ar １５ , Ar １６ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, １ represents a crosslinkable group. １５ At least one atom adjacent to the atom bonded to the nitrogen atom in the formula (I) is bonded to an alkyl group having 1 to 4 carbon atoms.

7. The composition according to claim 3, wherein the charge transporting polymer (α) has a unit represented by the following formula (3): (In formula (3), Ar １７ , Ar １８ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent, １ represents a crosslinkable group. １７ At least one atom adjacent to the atom bonded to the nitrogen atom in the formula (I) is bonded to an alkyl group having 1 to 4 carbon atoms.

8. The composition according to claim 1, wherein the crosslinkable group is at least one group selected from the following group T of crosslinkable groups: (In the formula, R ２４ , R ２５ , and R ２６ each independently represents a hydrogen atom or an alkyl group, ２７ , R ２８ , and R ２９ each independently represents an alkyl group or an alkoxy group, Ar ２１ , and Ar ２２ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent; p represents an integer of 0 to 4; q represents an integer of 0 to 5; r represents an integer of 0 to 7; and * represents a bond.

9. A photoelectric conversion element comprising a pair of electrodes having an upper electrode and a lower electrode, an active layer located between the pair of electrodes and containing an organic-inorganic hybrid semiconductor compound, and a hole transport layer located between the active layer and the upper electrode or between the active layer and the lower electrode, wherein the photoelectric conversion element contains the composition according to claim 1 or 2.

10. A photoelectric conversion element having a pair of electrodes having an upper electrode and a lower electrode, an active layer located between the pair of electrodes and containing an organic-inorganic hybrid semiconductor compound, and a hole transport layer located between the active layer and the upper electrode or between the active layer and the lower electrode, wherein the hole transport layer contains a crosslinked product of the composition according to claim 1 or 2.

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