Compound, hole transport layer, composition, and power generation device

Abstract

This power generation device comprises: a pair of electrodes that are constituted of an upper electrode and a lower electrode; an active layer that is positioned between the pair of electrodes and contains an organic-inorganic hybrid semiconductor compound; and a hole transport layer that is positioned between the pair of electrodes. The hole transport layer includes a composition of a specific triarylamine compound.

Description

Compound, hole transport layer, composition and power generating device

[0001] The present invention relates to a compound, a hole transport layer, a composition, and a power generation device. This application claims priority to Japanese Patent Application No. 2023-118822, filed on July 21, 2023, the contents of which are incorporated herein by reference.

[0002] Known power generation devices include a pair of electrodes between which an active layer and a buffer layer are arranged. To improve the photoelectric conversion efficiency, the use of organic-inorganic hybrid semiconductor compounds as the active layer has been investigated, and compounds with a perovskite structure have attracted particular attention.

[0003] Organic semiconductor compounds and the like are used as hole transport materials in such power generation devices, and examples of such organic semiconductor compounds include polytriarylamine-based semiconductor compounds. For example, Patent Document 1 discloses a power generation device using a polytriarylamine-based semiconductor compound, which contains a combination of a charge injection resistance-increasing hole transport material such as polytriarylamine and an electron recombination-increasing hole transport material such as 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenylamino)-9,9'-spirobifluorene.

[0004] Japanese Patent Application Laid-Open No. 2021-022681

[0005] However, when conventional hole transport layers are used, problems such as poor stability of photoelectric conversion efficiency and poor interlayer adhesion, particularly in stacked devices, have been observed, such as insufficient charging performance. The present invention provides a power generation device having a hole transport layer containing a triarylamine compound, which exhibits sufficient power generation performance. The present invention also provides a compound that can be used in the hole transport layer provided in the power generation device.

[0006] As a result of intensive research into solving the above problems, the present inventors have found that the above problems can be solved by using a triarylamine having a specific structure, and have thus completed the present invention.

[0007] That is, the gist of the present invention is as follows: [1] A composition comprising a compound (I) represented by the following formula (I) and a polymer (II) represented by the following formula (II):

[0008] (In formula (I), R １１ ~R １５ each independently represents a hydrogen atom or a monovalent aliphatic hydrocarbon group, R １１ and R １５ At least one of Ar represents a monovalent aliphatic hydrocarbon; １１ and Ar １２ each independently represents a monovalent aromatic group, and n represents 1 to 3.

[0009] (In formula (II), R ２１ ~R ２５ each independently represents a hydrogen atom or a monovalent organic group; Ar ２１ and Ar ２２ each independently represents a monovalent aromatic group, m represents the degree of polymerization, and the average degree of polymerization is a natural number of 10 or more and 1,000 or less.

[0010] [2] In the formula (I), Ar １１ and Ar １２ [3] In the formula (I), R １１ ~R １５ [4] The composition according to [1] or [2], wherein at least one of R １１ ~R １５The composition according to any one of [1] to [3], wherein at least two of the above are aliphatic hydrocarbon groups having 1 to 20 carbon atoms. [5] The composition according to any one of [1] to [4], wherein the compound (I) represented by formula (I) contains a repeating unit of the polymer (II) represented by formula (II) in a partial structure. [6] A composition comprising a compound (V-1) and a polymer (V-2), wherein the compound (V-1) comprises a triarylamine structure, and a monovalent organic group is bonded to at least one of the atoms adjacent to the atom bonded to the nitrogen atom in at least one of three aromatic rings or heteroaromatic rings bonded to a nitrogen atom in the triarylamine structure in the compound (V-1), the molecular weight of the compound (V-1) is 100 to 5,000, the polymer (V-2) has a repeating unit containing a triarylamine structure, and a monovalent organic group is bonded to an atom adjacent to the atom bonded to the nitrogen atom in at least one of the three aromatic rings or heteroaromatic rings bonded to the nitrogen atom in the triarylamine structure in the repeating unit, and the weight average molecular weight of the polymer (V-2) is more than 5,000 and not more than 100,000. [7] The composition according to [6], wherein a nitrogen atom of the triarylamine structure in each repeating unit of the polymer (V-2) and two of the three aromatic or heteroaromatic rings bonded to the nitrogen atom constitute a main chain, and a monovalent organic group is bonded to at least one atom adjacent to the atom bonded to the nitrogen atom in the aromatic or heteroaromatic ring in the side chain. [8] The composition according to [6] or [7], wherein the monovalent organic group bonded to the aromatic or heteroaromatic ring in the compound (V-1) and the monovalent organic group bonded to the aromatic or heteroaromatic ring in the repeating unit of the polymer (V-2) are both aliphatic hydrocarbon groups. [9] The composition according to any one of [6] to [8], wherein the three aromatic or heteroaromatic rings in the triarylamine structure of the compound (V-1) and the three aromatic or heteroaromatic rings in the triarylamine structure of the polymer (V-2) are all benzene.

[10] The composition according to any one of [6] to [9], wherein the compound (V-1) contains a repeating unit of the polymer (V-2) as a partial structure.

[11] The composition according to any one of [1] to

[10] , further comprising an organic solvent.

[12] The composition according to any one of [1] to

[11] , further comprising a dopant.

[13] The composition according to any one of [1] to

[12] , further comprising a dopant, wherein the dopant comprises an iodonium salt represented by the following formula (X): [R. ６１ -I ＋ -R ６２ ]X － (X) (In formula (X), R ６１ and R ６２ are each independently a monovalent organic group, and X － represents any anion.)

[14] The composition according to any one of [1] to

[13] , wherein the dopant comprises a compound represented by the following formula (XI):

[0011] (In formula (XI), R ７１ ~R ７４ each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; Ar ７１ represents an aromatic hydrocarbon group or aromatic heterocyclic group having 6 to 30 carbon atoms, which may have a substituent, and n represents an integer of 0 to 5.

[0012]

[15] A hole transport layer comprising the composition according to any one of [1] to

[14] .

[16] A power generation device having a pair of electrodes composed of 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 pair of electrodes, wherein the hole transport layer comprises the composition according to any one of [1] to

[14] .

[17] The power generation device according to

[16] , wherein the organic-inorganic hybrid semiconductor compound comprises a compound having a perovskite structure.

[18] A compound represented by the following formula (III):

[0013] (In formula (III), R ３１ ~R ３５ each independently represents a hydrogen atom or a monovalent aliphatic hydrocarbon group; Ar ３１ and Ar ３２each independently represents a monovalent aromatic hydrocarbon group which may have a substituent, and n represents 1 to 3. ３１ ~R ３５ At least two of the groups represented by Ar represent a monovalent aliphatic hydrocarbon group. ３１ and Ar ３２

[20] In the formula (III), Ar is a biphenylyl group. ３１ and Ar ３２

[21] The compound according to any one of

[18] to

[20] , wherein in formula (III), n is 1.

[22] In formula (III), R １ ~R ５

[23] The compound according to any one of

[18] to

[21] , wherein at least two of R １ ~R ５

[24] A composition comprising a compound represented by formula (III) according to any one of items

[18] to

[23] .

[25] A hole transport layer comprising a compound represented by formula (III) according to any one of items

[18] to

[23] .

[26] A power generation device comprising a hole transport layer comprising a compound represented by formula (III) according to any one of items

[18] to

[23] .

[0014] The present invention can provide a power generating device having a hole transport layer containing a triarylamine compound, which device exhibits sufficient power generating performance, as well as a compound that can be used in the hole transport layer provided in the power generating device.

[0015] 1 is a cross-sectional view schematically showing an example of a power generation device; 2 is a cross-sectional view schematically showing an example of a solar cell including a power generation device; and 3 is a cross-sectional view schematically showing an example of a solar cell module including a power generation device.

[0016] The following describes in detail the embodiments of the present invention, but these descriptions are merely examples (typical examples) of the embodiments of the present invention, and the present invention is not limited to these details as long as it does not deviate from the gist of the present invention. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits, and "A to B" means A or more and B or less. Furthermore, in this specification, the term "independently," used when describing two or more objects together, means that the two or more objects may be the same or different.

[0017] The device of the present invention and the hole transport layer contained in the device contain a composition made up of the components shown below.

[0018] [Compound (V-1)] Compound (V-1) used in one embodiment of the present invention is a compound having a triarylamine structure in which three aromatic groups are bonded to a nitrogen atom.

[0019] [Aromatic Group] In this specification, the aromatic group may be an aromatic hydrocarbon group having a ring structure consisting only of carbon, or an aromatic heterocyclic group containing an element other than carbon in the ring structure. In addition, in this specification, an unsubstituted aromatic group and a substituted aromatic group are collectively referred to as an "aromatic group which may have a substituent" or simply as an "aromatic group". Examples of the aromatic group include groups derived from the aromatic hydrocarbon group P1 or aromatic heterocyclic group P2 below. Here, the "derived group" is preferably a monovalent group obtained by removing one hydrogen atom arbitrarily selected from the exemplified compounds. In this specification, the aromatic group is also referred to as an aryl group.

[0020] (Aromatic Hydrocarbon Group P1) Six-membered monocyclic rings or 2- to 5-condensed rings 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, and a fluorene ring.

[0021] (Aromatic Heterocycle Group P2) Five- or six-membered monocyclic rings or two- to four-fused rings, 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, and an azulene ring.

[0022] As the monovalent aromatic group (hereinafter also referred to as "aryl group"), from the viewpoints of solubility in organic solvents and heat resistance, a monovalent aromatic hydrocarbon group is preferred, a phenyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a triphenylenyl group, a pyrenyl group, and a fluorenyl group are more preferred, and a phenyl group and a fluorenyl group are even more preferred. Furthermore, as the monovalent aromatic heterocyclic group, a thiophenyl group and a pyridyl group are preferred. The substituent that may substitute any hydrogen atom of the above aromatic group is not particularly limited, and examples thereof include one or more selected from the following [Substituent Group Z1] and [Substituent Group Z2].

[0023] (Substituent Group Z1) Linear or branched alkyl groups preferably having 1 to 24 carbon atoms, more preferably 1 to 12 carbon atoms, and even more preferably 1 to 4 carbon atoms, such as a methyl group or an ethyl group; aryloxy groups preferably having 4 to 36 carbon atoms, and even 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, and even 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, and even 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, and even more 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 2 carbon atoms, and even 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; 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;

[0024] The formula weight of the substituent group Z1, including further substituted groups, is preferably 500 or less, and more preferably 250 or less. In terms of improving solubility in organic solvents, the substituent group Z1 that the aromatic group may have is preferably an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or a phenyl group, more preferably an alkyl group having 1 to 12 carbon atoms or a phenyl group, and even more preferably an alkyl group having 1 to 6 carbon atoms or a phenyl group. (Substituent group Z2)

[0025] Examples of the substituent group Z2 include substituents represented by the following formula (IV).

[0026] In the formula, R ４１ ~R ４４ Each independently represents a hydrogen atom or an alkyl group. ４１ represents a monovalent aromatic group, and ４１ The hydrogen atoms bonded to the carbon atoms in the benzocyclobutene ring may be substituted with a substituent. The substituent is preferably an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or a phenyl group, more preferably an alkyl group having 1 to 12 carbon atoms or a phenyl group, and even more preferably an alkyl group having 1 to 6 carbon atoms or a phenyl group. ４１ The substituents on the benzocyclobutene ring may be bonded together to form a ring.

[0027] As the monovalent aromatic group, a monovalent aromatic group having a substituent is preferred, and a phenyl group having a substituent and a fluorenyl group having a substituent are more preferred. As the phenyl group having a substituent, a phenyl group having a phenyl group at the fourth position, i.e., a biphenylyl group, is even more preferred. As the fluorenyl group having a substituent, a dimethylfluorenyl group is even more preferred, and a 9,9-dimethylfluorenyl group is particularly preferred. Note that when a monovalent group obtained by removing one arbitrarily selected hydrogen atom from fluorene constitutes at least one aromatic group, it is preferable that the hydrogen atom at the second position of the fluorene is removed.

[0028] [Triarylamine Structure] In this specification, the term "triarylamine structure" refers to a structure in which three aromatic or heteroaromatic ring groups are bonded to each nitrogen atom. The triarylamine structure in this specification has two bonds, and two different aromatic or heteroaromatic ring groups among the three aromatic or heteroaromatic ring groups bonded to the tertiary nitrogen atom each have a bond to the triarylamine structure. The bond chain formed by the two aromatic or heteroaromatic ring groups having two bonds in the triarylamine structure and the tertiary nitrogen atom to which the three aromatic or heteroaromatic ring groups are bonded is also referred to as the main chain of the triarylamine structure. Furthermore, the aromatic or heteroaromatic ring groups among the three aromatic or heteroaromatic ring groups bonded to the nitrogen atom in the triarylamine structure that do not form the main chain are also referred to as side chains.

[0029] In this specification, the three aromatic groups bonded to the nitrogen atom of the triarylamine structure may all be aromatic hydrocarbon groups, all may be aromatic heterocyclic groups containing elements other than carbon in the ring structure, or a combination of aromatic hydrocarbon groups and aromatic heterocyclic groups. Among these, it is preferable that the three aromatic groups are all the same aromatic hydrocarbon or aromatic heterocyclic groups, more preferably all the same aromatic hydrocarbon groups, and even more preferably all groups derived from benzene rings.

[0030] At least one of the three aromatic groups bonded to the nitrogen atom of the triarylamine structure in compound (V-1) has a monovalent organic group bonded to at least one of the atoms adjacent to the atom bonded to the nitrogen atom in the aromatic ring of the aromatic group. The monovalent organic group is preferably a monovalent aliphatic hydrocarbon, more preferably an alkyl group having 1 to 20 carbon atoms, even more preferably an alkyl group having 1 to 6 carbon atoms, and particularly preferably a methyl group. The aromatic group bonded to the monovalent organic group is preferably a side chain in the triarylamine structure.

[0031] (Molecular Weight) The molecular weight of the compound (V-1) is from 100 to 5,000, preferably from 300 to 2,500, and more preferably from 500 to 1,000.

[0032] [Compound (V-1-1)] As one embodiment of the compound (V-1), a compound (V-1-1) having a triarylamine structure represented by the following formula (V) is preferred.

[0033]

[0034] In formula (V), R ５１ and R ５２ each independently represents a hydrogen atom or a monovalent organic group, R ５１ and R ５２ At least one of Ar represents a monovalent organic group; ５１ and Ar ５３ each independently represents a divalent aromatic group, Ar ５２ represents a monovalent aromatic group. ４１ and R ４２ Ar bonded to ４２ The atom in the Ar bonded to the nitrogen atom of the triarylamine structure ４２ The atom is bonded to the adjacent atom. ５１ , Ar ５３ and a nitrogen atom, and Ar ５１ , Ar ５３ represents the main chain in the triarylamine structure of formula (V), and Ar ５２ and Ar ５２ The bond between the nitrogen atom and the alkyl group represents a side chain in the triarylamine structure of formula (V).

[0035] R ４１ and R ４２ As the alkyl group, a monovalent aliphatic hydrocarbon is preferable, an alkyl group having 1 to 20 carbon atoms is more preferable, an alkyl group having 1 to 6 carbon atoms is even more preferable, and a methyl group is particularly preferable.

[0036] Ar ４１ ~Ar ４３Although Ar may be all aromatic hydrocarbon groups, may be all aromatic heterocyclic groups containing elements other than carbon in the ring structure, or may be a combination of an aromatic hydrocarbon group and an aromatic heterocyclic group, it is preferable that they are all the same aromatic hydrocarbon or aromatic heterocyclic group, it is more preferable that they are all the same aromatic hydrocarbon groups, and it is even more preferable that they are all the same phenyl groups which may have a substituent. ５２ is preferably a 2,4,6-trimethylphenyl group.

[0037] The compound (V-1-1) has a structure in which the triarylamine structure represented by formula (V) is repeatedly bonded 2 to 4 times.

[0038] (Molecular Weight) The molecular weight range of the compound (V-1-1) is the same as that of the compound (V-1), and therefore the explanation is omitted.

[0039] The method for synthesizing compound (V-1) and compound (V-1-1) is not particularly limited. For example, compound (V-1) and compound (V-1-1) can be synthesized by a method such as that described in JP-A-2009-263665, in which compound (V-1) and compound (V-1-1) are synthesized by oxidative polymerization of a triarylamine monomer or a coupling reaction using a transition metal catalyst.

[0040] [Polymer (V-2)] The polymer (V-2) used in one embodiment of the present invention is a polymer having a triarylamine structure in the repeating unit.

[0041] The configuration of the three aromatic groups bonded to the nitrogen atom of the triarylamine structure contained in the repeating unit of polymer (V-2) is similar to the configuration of the three aromatic groups bonded to the nitrogen atom of the triarylamine structure in compound (V-1), and therefore further description is omitted. Furthermore, in the composition described below, when a monovalent aliphatic hydrocarbon is bonded as a monovalent organic group to at least one of the three aromatic groups bonded to the nitrogen atom of the triarylamine structure contained in compound (V-1), it is preferred that a monovalent aliphatic hydrocarbon is bonded as a monovalent organic group to at least one of the three aromatic groups bonded to the nitrogen atom of the triarylamine structure contained in the repeating unit of polymer (V-2). Furthermore, it is preferred that the side chain of the triarylamine structure in the repeating unit of polymer (V-2) is the same as the side chain of the triarylamine structure in compound (V-1).

[0042] (Average Degree of Polymerization) The average degree of polymerization of the polymer (V-2) is not particularly limited as long as it satisfies the range of the weight average molecular weight shown below.

[0043] (Molecular Weight) The weight average molecular weight of polymer (V-2) is greater than 5,000, preferably greater than 7,000, and more preferably 10,000 or greater. Furthermore, the weight average molecular weight of polymer (V-2) is 100,000 or less, preferably 50,000 or less. The range of the weight average molecular weight of polymer (V-2) may be freely selected from the above lower limit and upper limit values, and is, for example, greater than 5,000 and 100,000 or less, preferably greater than 7,000 and 50,000 or less, and more preferably 10,000 or more and 50,000 or less. In this specification, the weight average molecular weight is the weight average value measured by GPC in terms of polystyrene.

[0044] [Polymer (V-2-1)] As one embodiment of the polymer (V-2), a polymer (V-2-1) having a repeating unit represented by the above formula (V) is preferred.

[0045] R in polymer (V-2-1) ５１ , R ５２ and Ar ５１ ~Ar ５３The aspect of is the same as that of the compound (V-1-1), and therefore the explanation is omitted. ５１ , R ５２ and Ar ５１ ~Ar ５３ respectively represent R in polymer (V-2-1). ５１ , R ５２ and Ar ５１ ~Ar ５３ and Ar in the compound (V-1-1) and the polymer (V-2-1) are preferably all the same. ５１ ~Ar ５３ It is more preferable that all of are phenyl groups.

[0046] (Molecular Weight) The range of the weight-average molecular weight of the polymer (V-2-1) is the same as the range of the weight-average molecular weight of the polymer (V-2), and therefore, the explanation thereof will be omitted.

[0047] The average degree of polymerization of the polymer (V-2-1) is not particularly limited as long as the weight-average molecular weight of the polymer (V-2-1) is within the above range. However, from the viewpoint of enhancing the stability of the power generating device, the average degree of polymerization of the polymer (V-2-1) is preferably a natural number of 10 or more and less than 1,000.

[0048] The structure of the compound and polymer in the composition and hole transport layer of the present invention is １ This can be confirmed by H-NMR. However, depending on the substituent, １ There are cases where it is difficult to determine the identity using only H-NMR. １３ This can be confirmed by combining information from C-NMR and mass spectrometry (MS).

[0049] [Compound (I)] Compound (I) used in one embodiment of the present invention is a compound represented by the following formula (I).

[0050]

[0051] In formula (I), R １１ ~R １５ each independently represents a hydrogen atom or a monovalent aliphatic hydrocarbon group, R １１ and R １５ At least one of Ar represents a monovalent aliphatic hydrocarbon;１１ and Ar １２ each independently represents a monovalent aromatic group, and n represents 1 to 3. The compound represented by formula (I) may have different repeating units.

[0052] R １１ ~R １５ is not particularly limited as long as it is a hydrogen atom or a monovalent aliphatic hydrocarbon group. From the viewpoint of improving stability and durability, R １１ and R １５ At least one of R is a monovalent aliphatic hydrocarbon. １１ ~R １５ At least two of the groups R are preferably monovalent aliphatic hydrocarbon groups, more preferably alkyl groups having 1 to 20 carbon atoms, even more preferably alkyl groups having 1 to 6 carbon atoms, and most preferably methyl groups. １１ , R １３ and R １５ is a methyl group, and R １２ and R １４ is preferably hydrogen.

[0053] The method for synthesizing compound (I) is not particularly limited. For example, compound (I) can be synthesized by a method such as that described in JP-A-2009-263665, in which compound (I) is synthesized by oxidative polymerization of a triarylamine monomer or a coupling reaction using a transition metal catalyst.

[0054] In formula (I), n is 1 to 3, and n is preferably 1.

[0055] (Molecular Weight) The molecular weight of compound (I) is preferably 300 or more, more preferably 600 or more. On the other hand, it is preferably 2,500 or less, more preferably 1,000 or less. The range of the molecular weight of compound (I) may be freely combined from the above lower limit and the above upper limit, and is, for example, preferably 300 to 2,500, more preferably 500 to 1,000.

[0056] [Polymer (II)] The polymer (II) used in one embodiment of the present invention is a polymer represented by the following formula (II).

[0057]

[0058] In formula (II), R ２１ ~R ２５ each independently represents a hydrogen atom or a monovalent organic group; Ar ２１ and Ar ２２ each independently represents a monovalent aromatic group which may have a substituent, and m represents the degree of polymerization, the average degree of polymerization being a natural number of 10 or more and less than 1000. The compound represented by formula (II) may have different repeating units.

[0059] R ２１ ~R ２５ When R is a monovalent organic group, it is preferably a monovalent aliphatic hydrocarbon group from the viewpoint of improving compatibility with compound (I). ２１ ~R ２５ Specific preferred embodiments of the monovalent aliphatic hydrocarbon group are R １１ ~R １５ The polymer (II) is a polymer represented by the formula (II) in which R ２１ ~R ２５ is R of formula (I) of compound (I). １１ ~R １５ It is preferably the same as

[0060] Ar ２１ and Ar ２２ Specific preferred embodiments of the aromatic group optionally having a substituent and the substituent thereof are Ar in compound (I). １１ and Ar １２ Therefore, a duplicated explanation will be omitted.

[0061] The method for synthesizing the polymer (II) is not particularly limited, but like the compound (I), the polymer (II) can be synthesized by the method described in, for example, JP-A-2009-263665.

[0062] (Degree of Polymerization) m in formula (II) represents the degree of polymerization. The average value of the degree of polymerization represented by m, i.e., the average degree of polymerization of polymer (II), is not particularly limited as long as it is a natural number of 10 or more and less than 1,000. From the viewpoint of improving the stability of the power generation device, the lower limit of the average degree of polymerization of polymer (II) is preferably a natural number of 50 or more and less than 1,000. Polymer (II) having a molecular weight larger than that of compound (I) has charge transport ability in the main chain direction and has a rigid structure, which is preferable from the viewpoint of improving charge mobility. In addition, since polymer (II) has higher lipophilicity than compound (I), when compound (I) and polymer (II) form a hole transport layer, compound (I) is likely to be interposed between polymer (II) and the active layer at the interface with the active layer adjacent to the hole transport layer. As a result, adhesion between the hole transport layer and the active layer is improved.

[0063] (Molecular Weight) The weight average molecular weight of polymer (II) is preferably more than 7,000, more preferably 10,000 or more. Also, it is preferably 100,000 or less, more preferably 50,000 or less. The range of the weight average molecular weight of polymer (II) may be freely combined from the above lower limit and the above upper limit. For example, it is preferably more than 7,000 and 100,000 or less, more preferably more than 10,000 and 50,000 or less.

[0064] <Compound (III)> Compound (III) used in one embodiment of the present invention is a compound represented by the following formula (III).

[0065]

[0066] (In formula (III), R ３１ ~R ３５ each independently represents a hydrogen atom or a monovalent aliphatic hydrocarbon group; Ar ３１ and Ar ３２ each independently represents a monovalent aromatic hydrocarbon group which may have a substituent, and n represents 1 to 3. ３１ ~R ３５ At least two of represent a monovalent aliphatic hydrocarbon group.

[0067] R ３１ ~R ３５In the case where is an aliphatic hydrocarbon group, a specific preferred embodiment is when R １１ ~R １５ Since it is the same as Ar, a duplicated explanation will be omitted. ３１ and Ar ３２ Specific preferred embodiments of the aromatic hydrocarbon group optionally having a substituent and the substituent thereof are Ar in compound (I). １１ and Ar １２ Therefore, a duplicated explanation will be omitted.

[0068] The method for synthesizing compound (III) is not particularly limited, but like compound (I), compound (III) can be synthesized by the method described in JP-A-2009-263665, for example.

[0069] In formula (III), n is 1 to 3, and n is preferably 1.

[0070] (Molecular Weight) The molecular weight of compound (III) is preferably 300 or more, more preferably 500 or more. On the other hand, it is preferably 2,500 or less, more preferably 1,000 or less. The range of the molecular weight of compound (III) may be freely combined from the above lower limit and the above upper limit, and is, for example, preferably 300 to 2,500, more preferably 500 to 1,000.

[0071] <Composition> [First embodiment] A first embodiment of the composition of the present invention is a composition containing a compound (I) and a polymer (II).

[0072] Specific examples of the compound (I) in the first embodiment are shown below. Compound (I-i): In formula (I), Ar １１ and Ar １２ are each independently a monovalent aromatic group, and R １１ ~R １５ are each independently a hydrogen atom or a monovalent aliphatic hydrocarbon group, and R １１ and R １５ Compound (I), wherein at least one of Ar is a monovalent aliphatic hydrocarbon group, and n is 1 to 3. Compound (I-ii): Compound (I), wherein Ar １１ and Ar １２are each independently a monovalent aromatic group selected from a phenyl group or a fluorenyl group, each of which may have a substituent; R １１ ~R １５ are each independently a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and R １１ and R １５ Compound (I), wherein at least one of Ar is an alkyl group having 1 to 20 carbon atoms, and n is 1 to 3. Compound (I-iii): Compound (I), wherein Ar １１ and Ar １２ are the same monovalent aromatic group selected from a phenyl group or a fluorenyl group, both of which have a substituent; R １１ ~R １５ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and R １１ and R １５ Compound (I), wherein at least one of Ar is an alkyl group having 1 to 6 carbon atoms, and n is 1 to 3. Compound (I-iv): Compound (I), wherein Ar １１ and Ar １２ are both the same monovalent aromatic group selected from a 4-biphenylyl group or a 9,9-dimethyl-9H-fluoren-2-yl group, and R １１ , R １３ and R １５ is an alkyl group having 1 to 6 carbon atoms, and R １２ and R １４ Compound (I), wherein Ar is a hydrogen atom and n is 1. Compound (I-v): Compound (I), wherein Ar is a １１ and Ar １２ are both the same monovalent aromatic group selected from a 4-biphenylyl group or a 9,9-dimethyl-9H-fluoren-2-yl group, and R １１ , R １３ and R １５ is a methyl group, and R １２ and R １４ is a hydrogen atom, and n is 1.

[0073] Specific examples of the polymer (II) in the first embodiment of the composition of the present invention are shown below. Polymer (II-i): In formula (II), Ar ２１ and Ar ２２ are each independently a monovalent aromatic group, and R２１ ~R ２５ are each independently a hydrogen atom or a monovalent aliphatic hydrocarbon group, and R ２１ and R ２５ At least one of Ar is a monovalent aliphatic hydrocarbon group, and m is 10 to 1000. Polymer (II-ii): In formula (II), Ar ２１ and Ar ２２ are each independently a monovalent aromatic group selected from a phenyl group or a fluorenyl group, each of which may have a substituent; R ２１ ~R ２５ are each independently a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and R ２１ and R ２５ At least one of Ar is an alkyl group having 1 to 20 carbon atoms, and m is 20 to 500. Polymer (II-iii): In formula (II), Ar １１ and Ar １２ are the same monovalent aromatic group selected from a phenyl group or a fluorenyl group, both of which have a substituent; R １１ ~R １５ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and R １１ and R １５ At least one of Ar is an alkyl group having 1 to 6 carbon atoms, and m is 20 to 500. Polymer (II-iv): In formula (II), Ar １１ and Ar １２ are both the same monovalent aromatic group selected from a 4-biphenylyl group or a 9,9-dimethyl-9H-fluoren-2-yl group, and R １１ , R １３ and R １５ is an alkyl group having 1 to 6 carbon atoms, and R １２ and R １４ is a hydrogen atom, and m is 30 to 200. Polymer (II-v): In formula (II), Ar １１ and Ar １２ are both the same monovalent aromatic group selected from a 4-biphenylyl group or a 9,9-dimethyl-9H-fluoren-2-yl group, and R １１ , R １３ and R １５ is a methyl group, and R１２ and R １４ represents a hydrogen atom, and m is 30 to 200.

[0074] Combinations of compound (I) and polymer (II) in the first embodiment of the composition of the present invention include a combination of compound (I-i) and polymer (II-i), a combination of compound (I-ii) and polymer (II-ii), a combination of compound (I-iii) and polymer (II-iii), a combination of compound (I-iv) and polymer (II-iv), a combination of compound (I-v) and polymer (II-v), and the like. In the above combinations, in formula (I) and formula (II), Ar １１ and Ar ２１ , Ar １２ and Ar ２２ , R １１ and R ２１ , R １２ and R ２２ , R １３ and R ２３ , R １４ and R ２４ and R １５ and R ２５ are preferably the same functional groups.

[0075] In one aspect of the first embodiment, for example, in the combination of compound (I) and polymer (II), the content of compound (I-i), (I-ii), (I-iii), (I-iv), or (I-v) can be 0.1 to 30 mass% relative to the total mass of the composition, and the content of polymer (II-i), (II-ii), (II-iii), (II-iv), or (II-v) can be 0.1 to 30 mass% relative to the total mass of the composition. In this specification, the content of the compound and the polymer can be analyzed by high performance liquid chromatography (HPLC).

[0076] When the composition of the first embodiment is used as a coating composition for forming a hole transport layer described later, from the viewpoint of increasing the solubility of compound (I) in the composition and from the viewpoint of easily forming a hole transport layer with a sufficient thickness, in the combination of compound (I) and polymer (II), the sum of the contents of compound (I-i), (I-ii), (I-iii), (I-iv) or (I-v) and polymer (II-i), (II-ii), (II-iii), (II-iv) or (II-v) is preferably 0.5 to 30 mass%, more preferably 1 to 20 mass%, still more preferably 1.5 to 10 mass%, and particularly preferably 2 to 8 mass%, relative to the total mass of the composition. As a particularly preferred embodiment, for example, in a composition containing compound (I-iv) and polymer (II-iv), the sum of the contents of compound (I-iv) and polymer (II-iv) is preferably 0.5 to 30 mass%, more preferably 1 to 20 mass%, even more preferably 1.5 to 10 mass%, and particularly preferably 2 to 8 mass%, relative to the total mass of the composition.

[0077] Second Embodiment A second embodiment of the composition of the present invention is a composition containing a compound (V-1) and a polymer (V-2).

[0078] Specific examples of the compound (V-1) in the second embodiment are shown below. Compound (V-1-i): In formula (V), R ５１ and R ５２ each independently represents a hydrogen atom or a monovalent organic group, R ５１ and R ５２ At least one of Ar represents a monovalent organic group; ５１ and Ar ５３ each independently represents a divalent aromatic group, Ar ５２ Compound (V-1) containing two or three structures represented by formula (V), in which R represents a monovalent aromatic group. Compound (V-1-ii): Compound (V-1-ii) containing two or three structures represented by formula (V), in which R represents a monovalent aromatic group. ５１ and R ５２ each independently represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms; R ５１ and R ５２ At least one of Ar represents an alkyl group having 1 to 20 carbon atoms; ５１ and Ar ５３each independently represents a divalent aromatic hydrocarbon group, Ar ５２ Compound (V-1-1) containing two or three structures represented by formula (V), in which R represents a monovalent aromatic hydrocarbon group. Compound (V-1-iii): Compound (V-1-3) containing two or three structures represented by formula (V), in which R represents a monovalent aromatic hydrocarbon group. ５１ and R ５２ each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; R ５１ and R ５２ At least one of Ar represents an alkyl group having 1 to 6 carbon atoms; ５１ and Ar ５３ represent a divalent phenyl group which may have a substituent, and Ar ５２ Compound (V-1) containing two structures represented by formula (V), in which R represents a monovalent phenyl group having a substituent. Compound (V-1-iv): Compound (V-1) containing two structures represented by formula (V), in which R ５１ and R ５２ Each of Ar represents an alkyl group having 1 to 6 carbon atoms, ５１ and Ar ５３ Both represent a divalent phenyl group, and Ar ５２ has at least R as a substituent ５１ and R ５２ A compound (V-1) containing two structures represented by formula (V), in which Ar represents a phenyl group having an alkyl group having 1 to 6 carbon atoms. ５１ and Ar ５３ The divalent phenyl group represented by has no substituent. Compound (V-1-v): In formula (V), R ５１ and R ５２ Each of the represents a methyl group, and Ar ５１ and Ar ５３ Both represent a divalent phenyl group, and Ar ５２ represents a 2,4,6-trimethylphenyl group, a compound (V-1) containing two structures represented by formula (V). ５１ and Ar ５３ The divalent phenyl group represented by has no substituent.

[0079] Specific examples of the polymer (V-2) in the second embodiment are shown below. Polymer (V-2-i): In formula (V), R ５１ and R ５２ each independently represents a hydrogen atom or a monovalent organic group, R５１ and R ５２ At least one of Ar represents a monovalent organic group; ５１ and Ar ５３ each independently represents a divalent aromatic group, Ar ５２ represents a monovalent aromatic group, and the number of repeating units is 10 to 1,000. Polymer (V-2-ii): In formula (V), R ５１ and R ５２ each independently represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms; R ５１ and R ５２ At least one of Ar represents an alkyl group having 1 to 20 carbon atoms; ５１ and Ar ５３ each independently represents a divalent aromatic hydrocarbon group, Ar ５２ represents a monovalent aromatic hydrocarbon group, and the number of repeating units is 20 to 500. Polymer (V-2-iii): In formula (V), R ５１ and R ５２ each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; R ５１ and R ５２ At least one of Ar represents an alkyl group having 1 to 6 carbon atoms; ５１ and Ar ５３ represent a divalent phenyl group which may have a substituent, and Ar ５２ represents a monovalent phenyl group which may have a substituent, and the number of repeating units is 20 to 500. Polymer (V-2-iv): In formula (V), R ５１ and R ５２ Each of Ar represents an alkyl group having 1 to 6 carbon atoms, ５１ and Ar ５３ Both represent a divalent phenyl group, and Ar ５２ has at least R as a substituent ５１ and R ５２A polymer (V-2) having a repeating unit represented by formula (V), in which Ar represents a phenyl group having an alkyl group having 1 to 6 carbon atoms, and the number of repeating units is 30 to 200. ５１ and Ar ５３ The divalent phenyl group represented by the formula (V) has no substituent. Polymer (V-2-v): In the formula (V), R ５１ and R ５２ Each of the represents a methyl group, and Ar ５１ and Ar ５３ Both represent a divalent phenyl group, and Ar ５２ represents a 2,4,6-trimethylphenyl group, and the polymer (V-2) has a structure represented by formula (V) as a repeating unit, and the number of the repeating units is 30 to 200. ５１ and Ar ５３ The divalent phenyl group represented by has no substituent.

[0080] Combinations of compound (V-1) and polymer (V-2) in the second embodiment of the composition of the present invention include a combination of compound (V-1-i) and polymer (V-2-i), a combination of compound (V-1-ii) and polymer (V-2-ii), a combination of compound (V-1-iii) and polymer (V-2-iii), a combination of compound (V-1-iv) and polymer (V-2-iv), a combination of compound (V-1-v) and polymer (V-2-v), and the like. In the above combinations, in the formula (V) of compound (V-1) and polymer (V-2), Ar ５１ Comrades, Ar ５２ Comrades, Ar ５３ Comrade, R ５１ Peers and R ５２ It is preferable that the functional groups are the same.

[0081] As one aspect of the second embodiment, for example, in the combination of compound (V-1) and polymer (V-2), the content of compound (V-1-i), (V-1-ii), (V-1-iii), (V-1-iv), or (V-1-v) can be 0.1 to 30 mass% relative to the total mass of the composition, and the content of polymer (V-2-i), (V-2-ii), (V-2-iii), (V-2-iv), or (V-2-v) can be 0.1 to 30 mass% relative to the total mass of the composition.

[0082] When the composition of the second embodiment is used as a coating composition for forming a hole transport layer described later, from the viewpoint of increasing the solubility of compound (I) in the composition and from the viewpoint of easily forming a hole transport layer with a sufficient thickness, in the combination of compound (I) and polymer (II), the sum of the contents of compound (I-i), (I-ii), (I-iii), (I-iv) or (I-v) and polymer (II-i), (II-ii), (II-iii), (II-iv) or (II-v) is preferably 0.5 to 30 mass%, more preferably 1 to 20 mass%, still more preferably 1.5 to 10 mass%, and particularly preferably 2 to 8 mass%, relative to the total mass of the composition. As a particularly preferred embodiment, for example, in a composition containing compound (V-1-iv) and polymer (V-2-iv), the sum of the contents of compound (V-1-iv) and polymer (V-2-iv) is preferably 0.5 to 30 mass%, more preferably 1 to 20 mass%, even more preferably 1.5 to 10 mass%, and particularly preferably 2 to 8 mass%, relative to the total mass of the composition.

[0083] [Third embodiment] The third embodiment of the composition of the present invention is a composition containing compound (III). Specific examples of compound (III) in the third embodiment are shown below. Compound (III-i): In formula (III), Ar ３１ and Ar ３２ are each independently a monovalent aromatic group, and R ３１ ~R ３５ are each independently a hydrogen atom or a monovalent aliphatic hydrocarbon group, and R ３１ ~R ３５ Compound (III), wherein at least two of the groups are monovalent aliphatic hydrocarbon groups, and n is 1 to 3. Compound (III-ii): Compound (III), wherein Ar ３１ and Ar ３２ are each independently a monovalent aromatic group selected from a phenyl group or a fluorenyl group, each of which may have a substituent; R ３１ ~R ３５ are each independently a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and R ３１ ~R ３５Compound (III), wherein at least two of Ar are alkyl groups having 1 to 20 carbon atoms, and n is 1 to 3. Compound (III-iii): Compound (III), wherein Ar ３１ and Ar ３２ are the same monovalent aromatic group selected from a phenyl group or a fluorenyl group, both of which have a substituent; R ３１ ~R ３５ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and R ３１ ~R ３５ Compound (III), wherein at least two of Ar are alkyl groups having 1 to 6 carbon atoms, and n is 1 to 3. Compound (III-iv): Compound (III), wherein Ar ３１ and Ar ３２ are both the same monovalent aromatic group selected from a 4-biphenylyl group or a 9,9-dimethyl-9H-fluoren-2-yl group, and R ３１ , R ３３ and R ３５ is an alkyl group having 1 to 6 carbon atoms, and R ３２ and R ３４ is a hydrogen atom, and n is 1. Compound (III-v): In formula (III), Ar ３１ and Ar ３２ are both the same monovalent aromatic group selected from a 4-biphenylyl group or a 9,9-dimethyl-9H-fluoren-2-yl group, and R ３１ , R ３３ and R ３５ is a methyl group, and R ３２ and R ３４ is a hydrogen atom and n is 1, compound (III).

[0084] Examples of the compound (III) in the third embodiment of the composition of the present invention include the above-mentioned compounds (III-i) to (III-v). Furthermore, when the composition of the third embodiment is used as a coating composition for forming a hole transport layer described later, the composition of the third embodiment preferably contains a polymer (II). When the composition of the third embodiment contains a polymer (II), combinations of the compound (III) and the polymer (II) include a combination of the compound (III-i) and the polymer (II-i), a combination of the compound (III-ii) and the polymer (II-ii), a combination of the compound (III-iii) and the polymer (II-iii), a combination of the compound (III-iv) and the polymer (II-iv), and a combination of the compound (III-v) and the polymer (II-v). In the above combinations, in the formula (III) and the formula (II), Ar ３１ and Ar ２１ , Ar ３２ and Ar ２２ , R ３１ and R ２１ , R ３２ and R ２２ , R ３３ and R ２３ , R ３４ and R ２４ and R ３５ and R ２５ are preferably the same functional groups.

[0085] In one aspect of the third embodiment, the content of compound (III-i), (III-ii), (III-iii), (III-iv), or (III-v) can be 0.1 to 30% by mass relative to the total mass of the composition, and when the composition of the third embodiment contains polymer (II), the content of polymer (II-i), (II-ii), (II-iii), (II-iv), or (II-v) can be 0.1 to 30% by mass relative to the total mass of the composition.

[0086] When the composition of the third embodiment is used as a coating composition for forming a hole transport layer described later, from the viewpoint of increasing the solubility of compound (III) in the composition and from the viewpoint of easily forming a hole transport layer with a sufficient thickness, in the combination of compound (III) and polymer (II), the sum of the contents of compound (III-i), (III-ii), (III-iii), (III-iv) or (III-v) and polymer (II-i), (II-ii), (II-iii), (II-iv) or (II-v) is preferably 0.5 to 30 mass%, more preferably 1 to 20 mass%, still more preferably 1.5 to 10 mass%, and particularly preferably 2 to 8 mass%, relative to the total mass of the composition. As a particularly preferred embodiment, for example, in a composition containing compound (III-iv) and polymer (II-iv), the sum of the contents of compound (III-iv) and polymer (II-iv) is preferably 0.5 to 30 mass%, more preferably 1 to 20 mass%, even more preferably 1.5 to 10 mass%, and particularly preferably 2 to 8 mass%, relative to the total mass of the composition.

[0087] [Organic Solvent] The compositions of the first, second, and third embodiments preferably further contain an organic solvent. From the viewpoint of the solubility of the compound or polymer contained in the composition of each embodiment, the organic solvent is preferably a polar solvent. Examples of the polar solvent include linear esters such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate, phenyl acetate, methyl propionate, ethyl propionate, propyl propionate, phenyl propionate, methyl 3-methoxypropionate, methyl 3-ethoxypropionate, methyl lactate, and ethyl lactate; aromatic esters such as ethyl benzoate and ethyl picolinate; cyclic esters such as γ-butyrolactone and caprolactone; and ether esters such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol-1-monomethyl ether acetate, and propylene glycol-1-monoethyl ether acetate. Examples of suitable organic solvents include alcohols such as methanol, ethanol, and isopropanol; ketones such as acetone, methyl ethyl ketone, methyl isoamyl ketone, methyl amyl ketone, and cyclohexanone; ethers such as tetrahydrofuran, dioxane, anisole, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether; ether alcohols such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, and 3-methoxy-3-methyl-1-butanol; amides such as N,N-dimethylformamide and N-methylpyrrolidone; nitriles such as acetonitrile and benzonitrile; and dimethyl sulfoxide. Other preferred organic solvents include polyhaloaliphatic hydrocarbons such as chloroform and dichloromethane, and polyhaloaromatic compounds such as bromobenzene, iodobenzene, chlorobenzene, and dichlorobenzene. The organic solvent contained in the composition of this embodiment may be one type or two or more types.

[0088] [Dopant] The composition of the present embodiment preferably further contains one or more dopants, as described below. Substances that can be used as dopants include boron compounds such as tetrakis(pentafluorophenyl)borate, molybdenum compounds such as tris[1-(methoxycarbonyl)-2-(trifluoromethyl)-ethane-1,2-dithiolene]molybdenum, and organic compounds having a tetracyanoquinodimethane skeleton, such as 2,3,4,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane. The dopant preferably undergoes a charge transfer reaction with at least one organic semiconductor compound before or after the formation of the hole transport layer. Hypervalent iodine compounds are preferred as dopants because they have excellent solubility and generate electron-accepting active sites that function as oxidizing agents upon heating or the like.

[0089] It is known that hypervalent iodine compounds act as dopants for organic semiconductor compounds and exhibit electron-accepting properties (i.e., oxidizing agent properties). Electron-accepting dopants can improve the conductivity or hole transport ability of semiconductor compounds by removing electrons from the semiconductor compounds. In this way, hypervalent iodine compounds can improve the charge transport properties of semiconductor compounds.

[0090] A hypervalent iodine compound is a compound containing hypervalent iodine, and is defined as a compound containing iodine with an oxidation number of +3 or higher. For example, the dopant can be an iodine(III) compound or an iodine(V) compound. An iodine(V) compound containing pentavalent iodine can be, for example, a periodinane compound such as Dess-Martin periodinane. Examples of iodine(III) compounds containing trivalent iodine include compounds having an oxidized iodobenzene structure, such as (diacetoxyiodo)benzene, and diaryliodonium salts. Organic compounds containing trivalent iodine are preferred as dopants, as they exhibit good electron-accepting properties and are less likely to undergo reverse reactions if the molecules are destroyed during the oxidation process. Among these, diaryliodonium salts are more preferred.

[0091] Diaryliodonium salts are compounds represented by the formula [Ar-I ＋ -Ar]X－ Here, each of the two Ars independently represents a monovalent aromatic group. The aromatic group (aromatic group) is not particularly limited, and may be, for example, any of the aromatic groups already listed above. X － represents any anion. － Examples of the cations include halide ions, trifluoroacetate ions, tetrafluoroborate ions, and tetrakis(pentafluorophenyl)borate ions. X is preferred because it has high solubility and the reaction for producing the coating liquid can proceed smoothly. － is preferably an anion having a fluorine atom, and more preferably tetrakis(pentafluorophenyl)borate anion or tetrakis(2,3,5,6-trifluoro-4-(trifluoromethyl)phenyl)borate anion.

[0092] A preferred embodiment of the dopant is represented by general formula (X). － represents any anion, specific examples of which are as described above. ６１ -I ＋ -R ６２ ]X － (X)

[0093] In formula (X), R ６１ and R ６２ are each independently a monovalent organic group. Examples of the monovalent organic group include an aliphatic group or an aromatic group. Examples of the aliphatic group include an aliphatic hydrocarbon group having 1 to 30 carbon atoms or an aliphatic heterocyclic group having 4 to 30 carbon atoms. For example, the aliphatic group may be an alkyl group including a cycloalkyl group, an alkenyl group, or an alkynyl group, and specific examples include a methyl group, an ethyl group, a butyl group, a cyclohexyl group, or a tetrahydrofuryl group.

[0094] Examples of the aromatic group include an aromatic hydrocarbon group having 6 to 30 carbon atoms and an aromatic heterocyclic group having 2 to 30 carbon atoms. Examples of the aromatic group include a phenyl group, a naphthyl group, a biphenylyl group, a thienyl group, and a pyridyl group.

[0095] The aliphatic group and aromatic group may have a substituent, which is not particularly limited, and examples thereof include a halogenyl group, a hydroxyl group, a cyano group, an amino group, a carboxyl group, an ester group, an alkylcarbonyl group, an acetyl group, a sulfonyl group, a silyl group, a boryl group, a nitrile group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, a thio group, a seleno group, an aromatic hydrocarbon group, and an aromatic heterocyclic group.

[0096] R ６１ and R ６２ is preferably an aromatic hydrocarbon group having 6 to 20 carbon atoms, more preferably a phenyl group. Here, it is preferable that the aromatic hydrocarbon group has no substituent or has a linear or branched alkyl group having 1 to 6 carbon atoms. ６１ and R ６２ is particularly preferably a phenyl group having the alkyl group at the para position. A more preferred embodiment of the dopant is one represented by general formula (XI).

[0097]

[0098] In formula (XI), R ７１ ~R ７４ each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; Ar ７１ represents an aromatic hydrocarbon group or aromatic heterocyclic group having 6 to 30 carbon atoms, which may have a substituent; n represents an integer of 0 to 5;

[0099] The Ar ７１ The aromatic hydrocarbon group or aromatic heterocyclic group having 6 to 30 carbon atoms, which may have a substituent, is represented by R ６１ and R ６２ or an aromatic group of X －The content of the dopant relative to the total mass of the composition of this embodiment can be, for example, 0.001 to 10% by mass. Furthermore, when used as a coating composition to form a hole transport layer, taking into consideration the improvement in hole transport ability and the stability of the hole transport ability due to the addition of the dopant to compound (I), (III), or (V-1) and polymer (II) or polymer (V-2), the content of the dopant is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of the sum of the contents of compound (I), (III), or (V-1) and polymer (II) or polymer (V-2) in the composition. Furthermore, it is preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 50 parts by mass or less. The range of the dopant content may be freely combined from the above lower limit and the above upper limit, and is, for example, preferably 1 to 70 parts by mass, more preferably 5 to 60 parts by mass, and even more preferably 10 to 50 parts by mass.

[0100] <Power generation device> A power generation device according to one embodiment of the present invention is a power generation device comprising a pair of electrodes composed of 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 contains at least one of the compositions according to the first, second, and third embodiments.

[0101] FIG. 1 is a cross-sectional view schematically illustrating one embodiment of a power-generating device. The power-generating device illustrated in FIG. 1 is a power-generating device used in a typical thin-film solar cell, but the power-generating device according to the present invention is not limited to the one illustrated in FIG. 1. In the power-generating device 100 illustrated in FIG. 1, a lower electrode 101, an active layer 103, and an upper electrode 105 are arranged in this order. The power-generating device 100 also includes a buffer layer 102 between the lower electrode 101 and the active layer 103, and a buffer layer 104 between the upper electrode 105 and the active layer 103. At least one of the buffer layer 102 and the buffer layer 104 is a hole-transporting layer, and the hole-transporting layer contains at least one of the compositions according to the first, second, and third embodiments. The hole-transporting layer may also contain an organic semiconductor compound other than the compositions according to the first, second, and third embodiments, and may further contain a dopant. As shown in FIG. 1, the power generating device 100 may also include a substrate 106, and may include other layers such as an insulator layer and a work function tuning layer.

[0102] [Definition of Semiconductor] Generally, a semiconductor compound refers to a compound that can be used as a semiconductor material that exhibits semiconductor properties. In this specification, "semiconductor properties" are defined by the magnitude of carrier mobility in a solid state. As is well known, carrier mobility is an index that indicates how fast (or how many) charges (electrons or holes) can be moved. Specifically, in this specification, a "semiconductor" is a compound that has a carrier mobility of preferably 1.0×10 at room temperature (25° C.). －６ cm ２ / V·s or more, more preferably 1.0×10 －５ cm ２ / V·s or more, more preferably 5.0×10 －５ cm ２ / V·s or more, particularly preferably 1.0×10 －４ cm ２ The carrier mobility can be measured by, for example, measuring the IV characteristics of a field effect transistor or by a time-of-flight method.

[0103] [Buffer Layer] The power generation device has a buffer layer located between a pair of electrodes, and the buffer layer includes at least one hole transport layer. The hole transport layer is a layer containing an organic semiconductor compound having hole transport capability, preferably a dopant for the organic semiconductor compound. In FIG. 1 , at least one of buffer layers 102 and 104 serves as the hole transport layer. However, when forming the hole transport layer by a coating method, the active layer 103 may be immersed in the coating solvent and may affect the active layer 103. Therefore, the hole transport layer is preferably located between the lower electrode 101 and the active layer 103. The buffer layer separate from the hole transport layer may function as an electron transport layer. Note that a buffer layer provided between an anode and an active layer may be referred to as a hole transport layer, and a buffer layer provided between a cathode and an active layer may be referred to as an electron transport layer.

[0104] [Hole Transport Layer] The hole transport layer according to one aspect of the present invention contains at least one of the compositions according to the first, second, and third embodiments. When the hole transport layer contains the composition according to the first embodiment, it may or may not contain compound (III), (V-1), or polymer (V-2). When the hole transport layer contains the composition according to the first embodiment, the content of compound (I) is preferably greater than the content of polymer (II), from the viewpoint of improving adhesion between the hole transport layer and an adjacent layer. The weight ratio of {compound (I) / polymer (II)} in the hole transport layer is preferably 0.5 to 6.0, more preferably 1.0 to 4.0, and even more preferably 1.5 to 3.0. When the hole transport layer contains the composition according to the second embodiment, it may or may not contain compound (I), (III), or polymer (II). When the hole transport layer contains the composition according to the second embodiment, the content of compound (IV) is preferably greater than the content of polymer (V-2), from the viewpoint of improving adhesion between the hole transport layer and an adjacent layer. The weight ratio of {compound (IV) / polymer (V-2)} in the hole transport layer is preferably 0.5 to 6.0, more preferably 1.0 to 4.0, and even more preferably 1.5 to 3.0. When the hole transport layer contains the composition of the third embodiment, it may or may not contain compound (I), (V-1), polymer (II), or polymer (V-2). When the composition of the third embodiment is contained, it is preferable to contain at least one of polymers (II) and (V) from the viewpoint of improving adhesion between the hole transport layer and an adjacent layer. Among them, it is preferable that the content of compound (III) in the hole transport layer is greater than the content of polymer (II) or (V) or the total content of polymers (II) and (V). The weight ratio of {compound (III) / polymer (II)}, {compound (III) / polymer (V-2)} or [compound (III) / {polymer (II)+polymer (V-2)}] in the hole transport layer is preferably from 0.5 to 6.0, more preferably from 1.0 to 4.0, and even more preferably from 1.5 to 3.0.

[0105] The proportions of the compounds and polymers contained in the hole transport layer reflect the proportions of the compounds and polymers contained in the hole transport material composition when the hole transport layer is formed. The hole transport layer of this aspect is a film of the hole transport material composition. Here, the hole transport material composition preferably contains the composition of the first, second, or third embodiment and an organic solvent, and further contains a dopant described below.

[0106] (Dopant) The hole transport layer preferably contains a dopant for the organic semiconductor compound (triarylamine), and the form thereof is not particularly limited. The dopant is a compound for optimizing the conductivity and hole transport ability of the hole transport layer relative to the active layer, and is not particularly limited as long as it is a compound that can impart electric charge.

[0107] The content of the dopant in the hole transport layer is not particularly limited, but from the viewpoints of chemically assisting charge transport in the hole transport layer and imparting a certain level of hole mobility while also ensuring a charge transport path in the organic semiconductor compound responsible for charge transport, the content is usually 0.001 wt % or more, preferably 0.01 wt % or more, more preferably 0.05 wt % or more, even more preferably 0.07 wt % or more, and particularly preferably 0.1 wt % or more, and is usually 30 wt % or less, preferably 20 wt % or less, more preferably 15 wt % or less, even more preferably 12 wt % or less, and particularly preferably 10 wt % or less, relative to the total weight of the hole transport layer composition. The content of the dopant in the hole transport layer may be freely selected from the above-mentioned lower limit and upper limit, and is, for example, preferably from 0.001 to 30 wt %, more preferably from 0.01 to 20 wt %, still more preferably from 0.05 to 15 wt %, particularly preferably from 0.07 to 12 wt %, and even more particularly preferably from 0.1 to 10 wt %, relative to the total weight of the hole transport layer composition. Further, in the hole transport layer, the content ratio of the dopant relative to the organic semiconductor compound such as the compound (I) and polymer (II) is not particularly limited, but in consideration of the improvement of hole transport ability and the stability of hole transport ability by adding the dopant to the compound (I), (III) or (V-1) and polymer (II) or polymer (V-2), the content of the dopant is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 10 parts by mass or more, relative to 100 parts by mass of the sum of the contents of the compound (I), (III) or (V-1) and polymer (II) or polymer (V-2) in the composition. Also, 70 parts by mass or less is preferable, 60 parts by mass or less is more preferable, and 50 parts by mass or less is even more preferable. The range of the dopant content may be freely combined from the above lower limit and the above upper limit, for example, 1 to 70 parts by mass is preferable, 5 to 60 parts by mass is more preferable, and 10 to 50 parts by mass is even more preferable. When the power generating device has a plurality of buffer layers, it is sufficient that at least one of the layers corresponding to the hole transport layer satisfies the above content range.

[0108] The content of the dopant represented by formula (X) or formula (XI) in the hole transport layer is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 10 parts by mass or more, relative to 100 parts by mass of the sum of the contents of compound (I), (III) or (V-1) and polymer (II) or polymer (V-2) in the composition, taking into consideration the improvement of hole transport ability and the stability of hole transport ability due to the addition of the dopant to compound (I), (III) or (V-1) and polymer (II) or polymer (V-2). Also, 70 parts by mass is preferred, more preferably 60 parts by mass or less, and even more preferably 50 parts by mass or less. The range of the dopant content may be freely combined from the above lower limit and the above upper limit, and is, for example, preferably 1 to 70 parts by mass, more preferably 5 to 60 parts by mass, and even more preferably 10 to 50 parts by mass. Within the above preferred range, the photoelectric conversion efficiency of the power generating device can be increased without impairing the adhesion between the hole transport layer and the layer adjacent thereto.

[0109] The dopant and the composition of the first, second, and third embodiments contained in the hole transport layer reflect the content ratio of each compound in the hole transport material composition when the hole transport layer is formed. The hole transport layer of this aspect is a film of a hole transport material. Here, the hole transport material composition contains at least one of the compositions of the first, second, and third embodiments, an organic solvent, and a dopant.

[0110] (Other Substances) The buffer layer serving as a hole transport layer may contain substances other than the above-mentioned organic semiconductor compound and dopant, such as a photoelectric conversion (active layer) material, an adhesive functional material, a filler, or a strength-assisting material.

[0111] [Electron Transport Layer] The power-generating device may have a buffer layer as an electron transport layer in addition to the buffer layer as the hole transport layer described above. Hereinafter, the buffer layer will also be referred to as the electron transport layer. The form of the buffer layer is not particularly limited, and any material capable of improving the efficiency of electron extraction from the active layer to the cathode may be used, and known materials may be used. Specific examples include inorganic compounds and organic compounds described in known publications such as WO 2013 / 171517, WO 2013 / 180230, and JP 2012-191194A, as well as the organic-inorganic perovskite compound according to the present invention. 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 the organic compound 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 or phosphine sulfide compounds.

[0112] The thickness of the buffer layer as a hole transport layer and the thickness of the buffer layer as an electron transport layer are not particularly limited and can be set appropriately depending on the application, but in one embodiment, they can be independently 0.5 nm or more, 1 nm or more in another embodiment, and 5 nm or more in yet another embodiment, and on the other hand, they can be 1 μm or less in one embodiment, 500 nm or less in another embodiment, 200 nm or less in yet another embodiment, and 150 nm or less in yet another embodiment. When the film thickness of the buffer layer is within the above range, the mobility efficiency of hole and electron carriers is likely to be improved, and the photoelectric conversion efficiency can be improved.

[0113] The buffer layer as a hole transport layer and the buffer layer as an electron transport layer can be formed by any method without limitation, and the method can be selected according to the characteristics of the material. For example, the buffer layer can be formed by preparing a coating solution containing the organic semiconductor compound, a dopant, and a solvent, and using a wet film formation method such as a spin coating method or an inkjet method. The buffer layer can also be formed by a dry film formation method such as a vacuum deposition method.

[0114] [Electrode] The electrode has the function of collecting holes and electrons generated by light absorption in the active layer 103. The power generation device 100 according to this embodiment has a pair of electrodes, one of which is called an upper electrode and the other is called a lower electrode. When the power generation device 100 has a substrate or is provided on a substrate, the electrode closer to the substrate can be called the lower electrode, and the electrode farther from the substrate can be called the upper electrode. Furthermore, a transparent electrode can be called the lower electrode, and an electrode that is less transparent than the lower electrode can be called the upper electrode. The power generation device 100 shown in FIG. 1 has a lower electrode 101 and an upper electrode 105.

[0115] The pair of electrodes can be an anode suitable for collecting holes and a cathode suitable for collecting electrons. In this case, the power generating device 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.

[0116] At least one of the pair of electrodes needs to be light-transmitting, and both may be light-transmitting. Light-transmitting means that 40% or more of sunlight passes through. In addition, a sunlight transmittance of 70% or more of the transparent electrode is preferable because more light passes through the transparent electrode and reaches the active layer 103. The light transmittance can be measured using a spectrophotometer (for example, U-4100 manufactured by Hitachi High-Technologies Corporation).

[0117] There are no particular limitations on the constituent members and manufacturing methods of the lower electrode 101 and the upper electrode 105, or the anode and the cathode, and well-known techniques can be used. For example, members and manufacturing methods described in known documents such as WO 2013 / 171517, WO 2013 / 180230, or JP 2012-191194 A can be used.

[0118] [Active Layer] The power generation device 100 has an active layer 103 located between a pair of electrodes, containing an organic-inorganic hybrid semiconductor compound, and performing photoelectric conversion. When the power generation device 100 receives light, the light is absorbed by the active layer 103 to generate carriers, which are then extracted from the lower electrode 101 and the upper electrode 105. An organic-inorganic hybrid semiconductor material is a material in which organic components and inorganic components are combined at the molecular level or nanolevel and which exhibits semiconductor properties.

[0119] The organic-inorganic hybrid semiconductor material is preferably a compound having a perovskite structure (hereinafter, sometimes referred to as a perovskite semiconductor compound). A perovskite semiconductor compound refers to a semiconductor compound having a perovskite structure. There are no particular limitations on the perovskite semiconductor compound, and it can be selected from, for example, those listed in Galasso et al. Structure and Properties of Inorganic Solids, Chapter 7 - Perovskite type and related structures. For example, a perovskite semiconductor compound having the general formula AMX ３ AMX expressed as ３ of the type or of general formula A ２ MX ４ A represented by ２ MX ４ Here, M represents a divalent cation, A represents a monovalent cation, and X represents a monovalent anion.

[0120] There are no particular limitations on the monovalent cation A, but those described in the above-mentioned book by Galasso can be used. More specific examples include cations containing elements from Groups 1 and 13 to 16 of the periodic table. 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. There are also no particular limitations on the substituents. Specific examples of optionally substituted ammonium ions include alkylammonium ions and arylammonium ions. In particular, to avoid steric hindrance, monoalkylammonium ions that form a three-dimensional crystal structure are preferred, and from the perspective of improving stability, alkylammonium ions substituted with one or more fluorine groups are preferred. Furthermore, a combination of two or more cations can be used as cation A.

[0121] Specific 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.

[0122] The divalent cation M is not particularly limited, but is preferably a divalent metal cation or semimetal cation. Specific examples include cations of elements in Group 14 of the periodic table, and more specific examples include lead cations (Pb ２＋ ), tin cations (Sn ２＋ ), germanium cation (Ge ２＋) In addition, a combination of two or more types of cations can be used as the cation M. From the viewpoint of obtaining a stable power generating device, it is particularly preferable to use a lead cation or two or more types of cations including a lead cation.

[0123] Examples of monovalent anions X include halides, acetate ions, nitrate ions, sulfate ions, borate ions, acetylacetonate ions, carbonate ions, citrate ions, sulfur ions, tellurium ions, thiocyanate ions, titanate ions, zirconate ions, 2,4-pentanedionate ions, and silicofluorides. To adjust the band gap, X may be a single anion or a combination of two or more anions. In one embodiment, X may be a halide ion or a combination of a halide ion and another anion. Examples of halide ions X include chloride ions, bromide ions, and iodide ions. While iodide ions or bromide ions are preferably used primarily to avoid excessively widening the band gap of the semiconductor, iodide ions and bromide ions may also be combined in an appropriate ratio.

[0124] Preferred examples of the perovskite semiconductor compound include organic-inorganic perovskite semiconductor compounds, particularly halide-based organic-inorganic perovskite semiconductor compounds. Specific examples of the perovskite semiconductor compound include CH 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） Clｘ , C.H. ３ NH ３ PbI （３－ｘ） Br ｘ , C.H. ３ NH ３ PbBr （３－ｘ） Cl ｘ , C.H. ３ NH ３ Pb （１－ｙ） Sn ｙ I ３ , C.H. ３ NH ３ Pb （１－ｙ） Sn ｙ Br 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 , and CH in the above compounds ３ NH ３ Instead of CFH ２ NH ３ , C.F. ２ HNH ３ , or CF ３ NH ３ In addition, 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.

[0125] The active layer 103 may contain two or more types of perovskite semiconductor compounds. For example, two or more types of perovskite semiconductor compounds in which at least one of A, M, and X is different may be included in the active layer 103. The active layer 103 may also have a stacked structure formed of multiple layers containing different materials or having different components.

[0126] The amount of the perovskite semiconductor compound contained in the active layer 103 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 103, so as to obtain good semiconductor characteristics. There is no particular upper limit. Furthermore, the active layer 103 may contain an additive in addition to the perovskite semiconductor compound. Examples of the additive include inorganic compounds such as halides, oxides, or inorganic salts such as sulfides, sulfates, nitrates, or ammonium salts, or organic compounds.

[0127] There is no particular limit to the thickness of the active layer 103. In order to be able to absorb more light, the thickness of the active layer 103 is 10 nm or more in one embodiment, 50 nm or more in another embodiment, 100 nm or more in yet another embodiment, and 120 nm or more in yet another embodiment. On the other hand, in order to reduce the series resistance or increase the charge extraction efficiency, the thickness of the active layer 103 is 1500 nm or less in one embodiment, 1200 nm or less in another embodiment, and 800 nm or less in yet another embodiment.

[0128] The method for forming the active layer 103 is not particularly limited, and any method can be used. Specific examples include a coating method and a vapor deposition method (or a co-evaporation method). The coating method can be used because it allows the active layer 103 to be formed easily. For example, there is a method in which a coating liquid containing a perovskite semiconductor compound or a precursor thereof is applied, and if necessary, heated and dried to form the active layer 103. Furthermore, after applying such a coating liquid, the perovskite semiconductor compound can also be precipitated by further applying a solvent in which the perovskite semiconductor compound has low solubility.

[0129] The precursor of the perovskite semiconductor compound refers to a material that can be converted into a perovskite semiconductor compound after the coating liquid is applied. As a specific example, a precursor of the perovskite semiconductor compound that can be converted into a perovskite semiconductor compound by heating can be used. For example, a compound represented by the general formula AX and a compound represented by the general formula MX can be used. ２ A coating solution can be prepared by mixing a compound represented by the general formula AMX with a solvent, and then heating and stirring the mixture. ３ The solvent is not particularly limited as long as it dissolves the perovskite semiconductor compound and the additive, and examples thereof include organic solvents such as N,N-dimethylformamide.

[0130] Any method can be used as a method for applying the coating liquid, 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.

[0131] The band gap can be calculated from the absorption edge wavelength and absorbance of the semiconductor compound. Specifically, a semiconductor compound thin film is formed on an appropriate sample such as a transparent glass substrate, and its transmission spectrum is measured. The horizontal axis represents wavelength, and the vertical axis represents transmittance (√(ahν)). The absorption rise is fitted as a straight line, and the eV value at which the line intersects with the baseline can be calculated as the band gap. The transmission spectrum can be measured using a spectrophotometer such as the Hitachi High-Tech U-4100.

[0132] The ionization potential of the active layer can be adjusted to the desired range by, for example, appropriately changing the cation component in the perovskite semiconductor compound.The band gap of the active layer can be adjusted to the desired range by, for example, appropriately changing the composition ratio of halogen elements in the perovskite semiconductor compound.

[0133] [1-4. Substrate] The power generation device 100 typically has a substrate 106 that serves as a support. However, the power generation device according to this embodiment does not necessarily have to have the substrate 106. 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, or JP 2012-191194 A can be used.

[0134] [Method for manufacturing the power generation device] According to the method described above, the power generation device 100 can be manufactured by forming each layer constituting the power generation device 100. There are no particular limitations on the method for forming each layer constituting the power generation device 100, and the layers can be formed by a sheet-to-sheet (Manyo) method or a roll-to-roll method.

[0135] The roll-to-roll method is a method in which a flexible substrate wound in a roll 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. However, when attempting to deposit each layer using the roll-to-roll method, due to its structure, contact between the deposition surface and the roll can cause scratches on the film or partial peeling.

[0136] 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 the roll-to-roll manufacturing equipment, but the upper limit of the outer diameter is preferably 5 m or less, more preferably 3 m or less, and more preferably 1 m or less. On the other hand, the lower limit is preferably 10 cm or more, more preferably 20 cm or more, and more preferably 30 cm or more. The upper limit of the outer diameter of the roll core is preferably 4 m or less, more preferably 3 m or less, and more preferably 0.5 m or less. On the other hand, the lower limit is preferably 1 cm or more, more preferably 3 cm or more, more preferably 5 cm or more, even more preferably 10 cm or more, and particularly preferably 20 cm or more. These diameters being below the above upper limit are preferred in terms of high roll handleability, while being above the lower limit are preferred in terms of reducing the possibility of the layers formed in each process being destroyed by bending stress. The lower limit of the roll width is preferably 5 cm or more, more preferably 10 cm or more, and more preferably 20 cm or more. On the other hand, the upper limit is preferably 5 m or less, more preferably 3 m or less, and more preferably 2 m or less. A width equal to or less than the upper limit is preferable because the roll is easy to handle, and a width equal to or greater than the lower limit is preferable because the size of the power generation device 100 is more flexible.

[0137] After the upper electrode 105 is laminated, the power generation device 100 can be heated at a temperature range of 50°C or higher or 80°C or higher, or 300°C or lower, 280°C or lower, or 250°C or lower (this process may be referred to as an annealing process). Performing the annealing process at a temperature of 50°C or higher improves the adhesion between the layers of the power generation device 100, for example, between the buffer layer 102 and the lower electrode 101, or between the buffer layer 102 and the active layer 103. The improved adhesion between the layers can improve the thermal stability and durability of the power generation device. Setting the temperature of the annealing process to 300°C or lower reduces the possibility of thermal decomposition of the organic compounds contained in the power generation device 100. The annealing process may be performed in stages using different temperatures within the above temperature range.

[0138] The heating time is 1 minute or more in one embodiment, 3 minutes or more in another embodiment, and 180 minutes or less in one embodiment, and 60 minutes or less in another embodiment, in order to improve adhesion while suppressing thermal decomposition. The annealing process can be terminated when the open circuit voltage, short circuit current, and fill factor, which are parameters of solar cell performance, reach certain values. The annealing process can be carried out under normal pressure and in an inert gas atmosphere to prevent thermal oxidation of the constituent materials. As a heating method, the power generation device may be placed on a heat source such as a hot plate, or may be placed in a heated atmosphere such as an oven. Heating may be carried out batchwise or continuously.

[0139] [Photoelectric Conversion Characteristics] The photoelectric conversion characteristics of the power generation device 100 can be determined as follows. Light of an appropriate spectrum is irradiated onto the power generation device 100 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.

[0140] The photoelectric conversion efficiency (PCE) is calculated by dividing the output (maximum output) at the optimum operating point of the current-voltage curve of the power generation device by the total energy of the irradiated light (for example, 100 mW / cm for sunlight with an intensity of AM 1.5 G). ２ ) is the value (%) divided by

[0141] [Method of Use] In one embodiment, the power generation device 100 is suitable for use as a photovoltaic device. FIG. 2 is a cross-sectional view schematically illustrating the configuration of a solar cell according to one embodiment of the present invention. FIG. 2 illustrates a solar cell according to one embodiment of the present invention. As shown in FIG. 2, a thin-film solar cell 14 according to this embodiment includes, in this order, a weather-resistant protective film 1, an ultraviolet-blocking film 2, a gas barrier film 3, a getter material film 4, an encapsulant 5, a solar cell element 6, an encapsulant 7, a getter material film 8, a gas barrier film 9, and a back sheet 10. The thin-film solar cell 14 according to this embodiment includes the above-described power generation device as the solar cell element 6. Light is irradiated from the side on which the protective film 1 is formed (the lower side in FIG. 2), causing the solar cell element 6 to generate electricity. The thin-film solar cell 14 does not need to include all of these components; any necessary components can be selected.

[0142] There are no particular limitations on the components that make up the power generation device or the manufacturing method thereof, and well-known techniques can be used, such as those described in known documents such as WO 2013 / 171517, WO 2013 / 180230, and JP 2012-191194 A.

[0143] The solar cell according to this embodiment, particularly the thin-film solar cell 14 described above, can be used for any purpose without any limitations on its application. For example, the solar cell according to one embodiment can be used as a solar cell for building materials, a solar cell for automobiles, a solar cell for interior decoration, a solar cell for railways, a solar cell for ships, a solar cell for airplanes, a solar cell for spacecraft, a solar cell for home appliances, a solar cell for mobile phones, or a solar cell for toys.

[0144] The solar cell according to this embodiment, particularly the above-described thin-film solar cell 14, may be used as it is, or may be used as a component of a solar cell module. For example, as shown in Fig. 3, a solar cell module 13 including the solar cell according to this embodiment, particularly the above-described solar cell 14, on a substrate 12 may be fabricated, and this solar cell module 13 may be installed at a location where it is to be used.

[0145] The features of the present invention will be explained in more detail below with reference to experimental examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following experimental examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

[0146] <Synthesis Examples> The synthesis methods of the compounds and polymers used in the experimental examples are shown below.

[0147] [Intermediate (i-1)] The titled intermediate (i-1) was obtained using 2,4,6-trimethylaniline (4.05 g, 30 mmol) and 4-bromobiphenyl (4.66 g, 20 mmol) and reaction conditions described in a patent document (JP 2019-175970 A) with reference to the method described therein.

[0148]

[0149] Intermediate (i-1): １ H-NMR (400MHz, solvent: deuterated chloroform): δ7.52 (d, J = 8.8Hz, 2H), δ7.41-7.35 (m, 4H), δ6. 95 (s, 2H), δ6.55 (d, J=8.8Hz, 2H), δ5.17 (s, 1H), δ2.31 (s, 3H), δ2.20 (s, 6H).

[0150] [Compound (I-1)] The titled compound (I-1) was obtained using intermediate (i-1) (3.16 g, 11 mmol) and 4,4'-dibromobiphenyl (1.56 g, 5.0 mmol) under reaction conditions according to the method described in Patent Document (JP 2019-175970 A).

[0151]

[0152] Compound (I-1): １ H-NMR (400 MHz, solvent: deuterated dichloromethane): δ 7.58-7.39 (m, 15H), δ 7.30-7.00 (m, 15H), δ 2.35 (s, 6H), δ 2.05 (s, 12H).

[0153] [Intermediate (i-2)] Using 2,4,6-trimethylaniline (3.82 g, 27.3 mmol) and 9,9-dimethyl-2-bromofluorene (4.98 g, 18.2 mmol), the reaction conditions were determined with reference to the method described in Patent Document (JP 2019-175970 A). Intermediate (i-2) was obtained.

[0154]

[0155] Intermediate (i-2): １ H-NMR (400MHz, solvent: deuterated chloroform): δ7.54 (d, J = 7.2Hz, 1H), δ7.46 (d, J = 8.0Hz, 1H), δ7.33 (d, J = 8.0Hz, 1H) , δ7.27-7.23 (m, 1H), δ7.19-7.15 (m, 1H), δ6.96 (s, 2H), δ6.55 (d, J = 2.0Hz, 1H), δ6.44 (dd, J = 2.0Hz, J=8.0Hz, 1H), δ5.22 (s, 1H), δ2.32 (s, 3H), δ2.20 (s, 6H), δ1.41 (s, 6H).

[0156] [Compound (I-2)] The titled compound (I-2) was obtained using intermediate (i-2) (5.50 g, 16.8 mmol) and 4,4'-dibromobiphenyl (2.43 g, 7.81 mmol) under reaction conditions according to the method described in Patent Document (JP 2019-175970 A).

[0157]

[0158] Compound (I-2): １ H-NMR (400 MHz, solvent: deuterated dichloromethane): δ 7.61-7.12 (m, 22H), δ 6.99 (s, 4H), δ 2.35 (s, 6H), δ 2.04 (s, 12H), δ 1.40 (s, 12H).

[0159] [Polymer (II-1)] Under a nitrogen atmosphere, 2,4,6-trimethylaniline and 4,4'-dibromobiphenyl were placed in a two-necked recovery flask at a molar ratio of approximately 1:1, and dichlorobis(di-t-butyl(4-dimethylaminophenyl)phosphine)palladium (2 mol%) was further added as a catalyst. The mixture was stirred in toluene at 90°C. After the reaction was completed, the mixture was cooled to room temperature, a poor solvent was poured into the reaction solution, and the resulting precipitate was filtered. The resulting solid was dissolved in toluene and passed through a short column of acidic silica gel. Filtration and concentration yielded the polymer (II-1) (number-average molecular weight 25,000, weight-average molecular weight 30,000). Polymer (II-1) is a compound corresponding to the aforementioned polymer (II), and is a compound represented by formula (II) in which m is in the range of 10 to 1,000. From the viewpoint of increasing charge mobility, m is preferably 20 to 500, and more preferably 30 to 200.

[0160]

[0161] Polymer (II-1): １ H-NMR (400MHz, solvent: deuterated chloroform): δ7.57-7.56 (m, 4H), δ7.50-7.46 (m, 8H), δ7.43-7.39 (m, 4H), δ7.31-7.27 (m, 2H), δ7.1 3-7.09 (m, 8H), δ6.84-6.82 (m, 4H), δ2.64-2.60 (m, 4H), δ1.68-1.60 (m, 4H), δ1.38-1.32 (m, 12H), δ0.90 (t, J=6.8Hz, 6H).

[0162] [Compound (XI-1)] 1.0 g of lithium tetrakis(4-trifluoromethyltetrafluorophenyl)borate and 470 mg of 4-methylphenyliodonium tosylate were dissolved in dichloromethane and stirred at room temperature for 10 hours. The reaction mixture was filtered, and the filtrate was concentrated. The crude product was purified by silica gel column chromatography to obtain the following compound (XI-1).

[0163]

[0164] Experimental Example 1 Preparation of Coating Solution for Electron Transport Layer Ultrapure water was added to a 15% by mass aqueous dispersion of tin (IV) oxide (manufactured by Alfa Aesar) to prepare a 7.5% by mass aqueous dispersion of tin oxide.

[0165] [Preparation of Active Layer Coating Solution] Lead (II) iodide was weighed into a vial and introduced into a glove box. N,N-dimethylformamide was added as a solvent to adjust the concentration of lead (II) iodide to 1.3 mol / L, and then the mixture was heated and stirred at 100°C for 1 hour to prepare Active Layer Coating Solution 1. Next, formamidine hydroiodide (FAI), methylamine hydrobromide (MABr), and methylamine hydrochloride (MACl) were weighed into another vial in a mass ratio of 10:1:1.5 and introduced into the glove box. Isopropyl alcohol was added as a solvent to this to prepare Active Layer Coating Solution 2, which had a total concentration of FAI, MABr, and MACl of 0.54 mol / L. 2-Phenylethylammonium iodide was weighed into another vial and introduced into the glove box. Isopropyl alcohol was added as a solvent so that the concentration of 2-phenylethylammonium iodide became 1 mg / mL, thereby preparing coating solution 3 for active layer.

[0166] [Preparation of Coating Solution for Hole Transport Layer] The synthesized compound (I-1) and polymer (II-1) were weighed into a vial at a weight ratio of 1:1, and anisole was added. The mixture was stirred at 100°C for 5 minutes to prepare a 35.2 mg / mL undoped hole transport solution. Separately, anisole was added to 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate (TPFB), an electron-accepting dopant, to prepare a 78 mM dopant solution. Next, 0.1 mL of the dopant solution was added to 1 mL of the undoped hole transport solution that had been returned to room temperature, and the resulting mixture was heated and stirred at 130°C for 1 hour to prepare a coating solution for the hole transport layer.

[0167] [Fabrication of a Power-Generating Device] A glass substrate (manufactured by Geomatec Co., Ltd.) with a patterned ITO transparent conductive film was subjected to ultrasonic cleaning using ultrapure water, drying with nitrogen blowing, and UV-ozone treatment. The above-described electron transport layer coating solution was spin-coated onto the glass substrate at room temperature (25°C) at a speed of 2000 rpm to a thickness of 60 nm, and then heated on a hot plate at 150°C for 10 minutes to form an electron transport layer. The glass substrate with this electron transport layer formed thereon was placed in a glove box, and active layer coating solution 1 (150 μL) heated to 100°C was dropped onto the electron transport layer, spin-coated at a speed of 2000 rpm, and then heat-annealed on a hot plate at 100°C for 10 minutes to form a lead iodide layer. Furthermore, after the glass substrate on which the lead iodide layer was formed was returned to room temperature, active layer coating liquid 2 (120 μL) was spin-coated onto the lead iodide layer at a speed of 2000 rpm, heated on a hot plate at 150 °C for 20 minutes, and then cooled to room temperature. Active layer coating liquid 3 (150 μL) was spin-coated onto the lead iodide layer at a speed of 2000 rpm and heated on a hot plate at 100 °C for 10 minutes to form an active layer (650 nm thick) of a perovskite semiconductor compound. Hole transport layer coating liquid (150 μL) was spin-coated onto this active layer at a speed of 1000 rpm, heated on a hot plate at 90 °C for 5 minutes, and then cooled to room temperature (25 °C) to form a hole transport layer (120 nm thick). An 80 nm thick gold layer was vapor-deposited onto this hole transport layer by resistance heating vacuum deposition to form an upper electrode. In this manner, a power generation device was fabricated.

[0168] Experimental Example 2 A power generating device was produced in the same manner as in Experimental Example 1, except that compound (XX-1): Spiro-OMeTAD (manufactured by Sigma-Aldrich, model number "792071") represented by the following formula (XX-1) was used instead of compound (I-1) used in Experimental Example 1.

[0169]

[0170] Experimental Example 3 A power generating device was produced in the same manner as in Experimental Example 1, except that compound (XX-2) represented by the following formula (XX-2) was used instead of compound (I-1) used in Experimental Example 1.

[0171]

[0172] Experimental Example 4 A power generating device was produced in the same manner as in Experimental Example 1, except that compound (XX-3) represented by the following formula (XX-3) was used instead of compound (I-1) used in Experimental Example 1.

[0173]

[0174] Experimental Example 5 A power generating device was fabricated in the same manner as in Experimental Example 1, except that a 35.2 mg / mL undoped hole transport solution was prepared using only the polymer (II-1) without using the compound (I-1) used in Experimental Example 1, and then doped.

[0175] [Evaluation of the power generation device] A 4 mm square metal mask was attached to the power generation device obtained in each example, and the current-voltage characteristics between the ITO electrode and the gold electrode were measured. For the measurement, a source meter (Keithley, Model 2400) was used, and the irradiation light source was a simulated sunlight light source with an air mass (AM) of 1.5 G and an irradiance of 100 mW / cm. ２ A solar simulator of the same model was used. The initial conversion efficiency PCE (%) of each photoelectric conversion element was calculated by dividing the maximum output energy of the current-voltage characteristics when the voltage was swept in the negative direction by the irradiated light energy. The ratio to Experimental Example 5 is shown in Table 1. Furthermore, a similar evaluation was performed on devices stored in a nitrogen-filled glove box 12 days after the formation of the upper electrode. The ratio of the conversion efficiency PCE after 12 days of storage to Experimental Example 5 is shown in Table 1.

[0176] [Evaluation of non-halogen solvent ink stability] The hole transport coating liquid of each example was visually observed for defects such as precipitation during storage at room temperature for two weeks. The ink was then transferred to a refrigerator set at 5°C and stored for 10 days, after which it was visually observed for defects such as precipitation. The results are shown in Table 1. (Evaluation criteria) ◯: No precipitation was observed. ×: Precipitation was observed.

[0177] [Evaluation of Interlayer Adhesion] The adhesion of each hole transport coating solution and the undoped hole transport solution before doping to the perovskite active layer was evaluated using a crosshatch test of the coating film. Active layer coating solution 1 and active layer coating solution 2 were formed on a glass substrate with an ITO film in the same manner as in the fabrication of a power generation device, and then heat-treated to form a perovskite active layer. The hole transport coating solution or the undoped hole transport solution was applied to this substrate using a spin coater and dried by heating on a hot plate at 90°C for 5 minutes. Eleven 1-mm-wide cuts reaching the substrate were made using a cutter guide, and then 11 more cuts were made by turning 90°. Next, cellophane adhesive tape was attached to the cut coating surface, and the edge of the tape was pulled perpendicular to the surface. The surface was then observed under an optical microscope to evaluate interlayer adhesion. The results are shown in Table 1. (Evaluation Criteria) ◯: No peeling was observed at the interface between the active layer and the hole transport layer, regardless of whether a dopant was present or not. ×: Peeling was observed at the interface between the active layer and the hole transport layer, regardless of whether a dopant was present or not.

[0178]

[0179] The hole transport layer coating solution of Experimental Example 5 has a common composition and is known to achieve high device characteristics. However, issues remain with respect to adhesion to the active layer and solubility in anisole, a non-halogen solvent. The results in Table 1 suggest that blending a compound with polymer (II-1) can improve adhesion to the active layer. This is thought to be due to an anchoring effect caused by the penetration of low-molecular-weight compounds into the active layer surface. While adhesion to the active layer tends to worsen with decreasing dopant concentration, no peeling was observed at the active layer / hole transport layer interface in the undoped composition containing the compound. Furthermore, blending a compound with polymer (II-1) also improved ink stability in anisole, a non-halogen solvent. This is due to the fact that the added compound has higher solubility in the solvent used than polymer (II-1). In other words, selecting an appropriate compound can broaden the range of solvents available. Furthermore, blending compound (I-1) with polymer (II-1) was shown to maintain properties equivalent to those of the reference Experimental Example 5 not only initially but also after 12 days of storage. By selecting a compound having a high structural similarity to be mixed with polymer (II-1), the polymer and the compound are uniformly mixed, and the doped state is stabilized, which is thought to improve the storage stability of the device.

[0180] Experimental Example 6: The synthesized compound (I-1) and polymer (II-1) were weighed into a vial at a weight ratio of 1:1, and orthodichlorobenzene was added and stirred to prepare a 35.2 mg / mL undoped hole transport solution. Separately, orthodichlorobenzene was added to compound (XI-1), an electron-accepting dopant, to prepare a 78 mM dopant solution. Next, 0.1 mL of the dopant solution was added to 1 mL of the undoped hole transport solution that had been returned to room temperature, and the resulting mixture was heated and stirred at 150°C for 1 hour to prepare a hole transport layer coating solution. A power generation device was fabricated using this ink in the same manner as in Experimental Example 1.

[0181] Experimental Example 7 A power generating device was produced in the same manner as in Experimental Example 6, except that instead of the composition used in Experimental Example 6, the weight ratio of compound (I-1) to polymer (II-1) was adjusted to 2:1.

[0182] Experimental Example 8 A power generating device was fabricated in the same manner as in Experimental Example 6, except that compound (I-2) was used instead of compound (I-1) used in Experimental Example 6.

[0183] Experimental Example 9 A power generating device was produced in the same manner as in Experimental Example 8, except that instead of the composition used in Experimental Example 8, the weight ratio of compound (I-2) to polymer (II-1) was adjusted to 2:1.

[0184] Experimental Example 10 A power generating device was fabricated in the same manner as in Experimental Example 6, except that a 35.2 mg / mL undoped hole transport solution was prepared using only the polymer (II-1) without using the compound (I-1) used in Experimental Example 6, and then doped.

[0185] Experimental Example 11 A power-generating device was fabricated in the same manner as in Experimental Example 6, except that a 35.2 mg / mL undoped hole-transporting solution was prepared using only the compound (I-1) without using the polymer (II-1) used in Experimental Example 6, and then doped.

[0186] Experimental Example 12 A power generating device was fabricated in the same manner as in Experimental Example 8, except that a 35.2 mg / mL undoped hole transport solution was prepared using only compound (I-2) without using polymer (II-1) used in Experimental Example 8, and then doped.

[0187] The power generating device was evaluated in the same manner as in Experimental Examples 1 to 5. The PCE ratio for Experimental Example 10 is shown in Table 2.

[0188]

[0189] The results in Table 2 demonstrate that the power generating device provided with a hole transport layer containing compound (I-1) and compound (I-2) exhibits photoelectric conversion properties, and that the mixture of compound (I-1) and compound (I-2) with polymer (II-1) exhibits even higher photoelectric conversion properties, and further demonstrates that the high photoelectric conversion properties are maintained even after 12 days of storage.

[0190] According to the present invention, it is possible to provide a power generating device that has a hole transport layer containing a triarylamine compound and that exhibits sufficient power generating performance.

[0191] 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 Power generation device 101 Lower electrode 102 Buffer layer 103 Active layer 104 Buffer layer 105 Upper electrode 106 Substrate

Claims

1. A composition comprising a compound (I) represented by the following formula (I) and a polymer (II) represented by the following formula (II): (In formula (I), R １１ ~R １５ each independently represents a hydrogen atom or a monovalent aliphatic hydrocarbon group; R １１ and R １５ At least one of Ar represents a monovalent aliphatic hydrocarbon; １１ and Ar １２ each independently represents a monovalent aromatic group, and n represents 1 to 3. (In formula (II), R ２１ ~R ２５ each independently represents a hydrogen atom or a monovalent organic group; R ２１ and R ２５ At least one of Ar represents a monovalent aliphatic hydrocarbon; ２１ and Ar ２２ each independently represents a monovalent aromatic group, m represents the degree of polymerization, and the average degree of polymerization is a natural number of 10 or more and 1000 or less.

2. In the formula (I), Ar １１ and Ar １２ The composition according to claim 1 , wherein each of the is independently an aromatic hydrocarbon group which may have a substituent.

3. In the formula (I), R １１ ~R １５ The composition according to claim 1, wherein at least one of the above is an aliphatic hydrocarbon group having 1 to 20 carbon atoms.

4. In the formula (I), R １１ ~R １５ The composition according to claim 1, wherein at least two of the above are aliphatic hydrocarbon groups having 1 to 20 carbon atoms.

5. The composition according to claim 1, wherein the compound (I) represented by formula (I) contains a repeating unit of the polymer represented by formula (II) in a partial structure.

6. A composition comprising a compound (V-1) and a polymer (V-2), wherein the compound (V-1) contains a triarylamine structure, and a monovalent organic group is bonded to at least one of the atoms adjacent to the atom bonded to the nitrogen atom in at least one of three aromatic rings or heteroaromatic rings bonded to a nitrogen atom of the triarylamine structure in the compound (V-1), the molecular weight of the compound (V-1) is 100 to 5,000, the polymer (V-2) has a repeating unit containing a triarylamine structure, and a monovalent organic group is bonded to an atom adjacent to the atom bonded to the nitrogen atom in at least one of the three aromatic rings or heteroaromatic rings bonded to the nitrogen atom of the triarylamine structure in the repeating unit, and the weight average molecular weight of the polymer (V-2) is more than 5,000 and not more than 100,000.

7. The composition according to claim 6, wherein a nitrogen atom of the triarylamine structure in each repeating unit of the polymer (V-2) and two of the three aromatic rings or heteroaromatic rings bonded to the nitrogen atom form a main chain, and a monovalent organic group is bonded to at least one of the atoms adjacent to the atom bonded to the nitrogen atom in the aromatic ring or heteroaromatic ring of the side chain.

8. The composition according to claim 6, wherein the monovalent organic group bonded to the aromatic ring or heteroaromatic ring of the compound (V-1) and the monovalent organic group bonded to the aromatic ring or heteroaromatic ring in the repeating unit of the polymer (V-2) are both aliphatic hydrocarbon groups.

9. The composition according to claim 6, wherein the three aromatic rings or heteroaromatic rings of the triarylamine structure of the compound (V-1) and the three aromatic rings or heteroaromatic rings of the triarylamine structure of the polymer (V-2) are all benzene.

10. The composition according to claim 6, wherein the compound (V-1) contains a repeating unit of the polymer (V-2) as a partial structure.

11. The composition according to any one of claims 1 to 10, further comprising an organic solvent.

12. The composition according to any one of claims 1 to 10, further comprising a dopant.

13. The composition according to any one of claims 1 to 10, further comprising a dopant, wherein the dopant comprises an iodonium salt represented by the following formula (X): [R ６１ -I ＋ -R ６２ ]X － (X) (In formula (X), R ６１ and R ６２ are each independently a monovalent organic group; － represents any anion.) 14. The composition of claim 13, wherein the dopant comprises a compound represented by formula (XI): (In formula (XI), R ７１ ~R ７４ each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; Ar ７１ represents an aromatic hydrocarbon group or aromatic heterocyclic group having 6 to 30 carbon atoms which may have a substituent, and n represents an integer of 0 to 5.

15. A hole transport layer comprising the composition of any one of claims 1 to 10.

16. A power generating device comprising a pair of electrodes composed of 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 pair of electrodes, wherein the hole transport layer contains the composition according to any one of claims 1 to 10.

17. The power generating device according to claim 16, wherein the organic-inorganic hybrid semiconductor compound includes a compound having a perovskite structure.

18. A compound represented by the following formula (III): (In formula (III), R ３１ ~R ３５ each independently represents a hydrogen atom or a monovalent aliphatic hydrocarbon group; Ar ３１ and Ar ３２ each independently represents a monovalent aromatic hydrocarbon group which may have a substituent, and n represents 1 to 3. ３１ ~R ３５ At least two of represent a monovalent aliphatic hydrocarbon group.

19. In the formula (III), Ar ３１ and Ar ３２ The compound of claim 18, wherein is a biphenylyl group.

20. In the above formula (III), Ar ３１ and Ar ３２ The compound according to claim 18 , wherein is an optionally substituted fluorenyl group.

21. The compound according to claim 18, wherein in formula (III), n is 1.

22. In formula (III), R ３１ ~R ３５ The compound according to claim 18, wherein at least two of the above are alkyl groups having 1 to 6 carbon atoms.

23. In formula (III), R ３１ ~R ３５ The compound of claim 18, wherein at least two of are methyl groups.

24. A composition comprising a compound represented by formula (III) as defined in claim 18.

25. A hole transport layer comprising a compound represented by formula (III) as defined in claim 18.

26. A power generating device comprising a hole transport layer comprising a compound represented by formula (III) as defined in claim 18.

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