Compound, hole transport material for photoelectric conversion element, and photoelectric conversion element and solar cell using the same

Abstract

To provide a hole transport material for a photoelectric conversion element realizing excellent photoelectric conversion efficiency, and a photoelectric conversion element and a solar cell using the hole transport material.SOLUTION: The invention provides a compound represented by the specified general formula (1), where X1 and X2 in the general formula (1) are each independently represented by the specified general formula (2).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a compound, a hole transport material for a photoelectric conversion element, and a photoelectric conversion element and a solar cell using the same. [Background technology]

[0002] In recent years, solar power generation has attracted attention as a clean energy source, and active development has been underway on solar cells as photoelectric conversion elements that convert solar energy into electrical energy. Among these, the development of solar cells using perovskite materials in the photoelectric conversion layer (hereinafter referred to as perovskite solar cells) has attracted attention as a next-generation solar cell that can be manufactured at low cost using a solution process (e.g., Patent Document 1, Non-Patent Documents 1 and 2).

[0003] In perovskite solar cells, a hole transport material for photoelectric conversion elements is often used in the element. The purposes of using it include (1) enhancing the function of selectively transporting holes to improve photoelectric conversion efficiency, and (2) protecting the perovskite material, which is susceptible to the effects of moisture and oxygen, by bonding with the perovskite photoelectric conversion layer (e.g., Non-Patent Document 3). Spiro-OMeTAD, a spirobifluorene-based organic compound, is often used as a standard hole transport material for photoelectric conversion elements.

[0004] While relatively high photoelectric conversion efficiencies can be achieved by using Spiro-OMETAD, the synthesis process is complicated, posing cost challenges, and there are also usage challenges, such as the time required for the photoelectric conversion efficiency to stabilize, which is not consistent (Non-Patent Document 4). Therefore, hole transport materials for photoelectric conversion devices that can solve these challenges are needed, but there are few reports of hole transport materials for photoelectric conversion devices that achieve photoelectric conversion efficiencies higher than Spiro-OMETAD. Given these current circumstances, there is a need for hole transport materials for photoelectric conversion devices that exhibit excellent photoelectric conversion properties and photoelectric conversion efficiency that is stable over time. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2017 / 104792 [Non-patent literature]

[0006] [Non-Patent Document 1] Journal of the American Chemical Society, 2009, Vol. 131, pp. 6050-6051 [Non-patent document 2] Science, 2012, Vol. 388, P. 643-647 [Non-patent document 3] Chemical Science,2019,10,P.6748-6769 [Non-patent document 4] Scientific Reports, 2012, Vol. 2, 591 Summary of the Invention [Problem to be solved by the invention]

[0007] The problem to be solved by the present invention is to provide a novel hole transport material for photoelectric conversion elements that can realize excellent photoelectric conversion efficiency when used in photoelectric conversion elements and solar cells, and a photoelectric conversion element and solar cell using the same. [Means for solving the problem]

[0008] In order to solve the above problems, the inventors have conducted extensive research and found that by using a compound having a specific structure or a combination of such compounds as a hole transport material for a photoelectric conversion element, a photoelectric conversion element and a solar cell that achieve high photoelectric conversion efficiency can be obtained.

[0009] 1. A compound represented by the following general formula (1), wherein X in the general formula (1) 1 and X2 are each independently represented by the following general formula (2):

[0010] [ka]

[0011] [In the formula, R 1 ~R 20 are each independently a hydrogen atom, a halogen atom, a carboxyl group, a trimethylsilyl group, a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent; a linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent; a linear or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent; a cycloalkyl group having 3 to 10 carbon atoms which may have a substituent; a linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent; a cycloalkoxy group having 3 to 10 carbon atoms which may have a substituent; an acyl group having 1 to 20 carbon atoms which may have a substituent; a thio group having 1 to 18 carbon atoms which may have a substituent; an amino group having 1 to 20 carbon atoms which may have a substituent; an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent; or a heterocyclic group having 5 to 36 ring atoms which may have a substituent, R 1 ~R 20 is at least one halogen atom, carboxyl group, trimethylsilyl group, a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent; a linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent; a linear or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent; a cycloalkyl group having 3 to 10 carbon atoms which may have a substituent; a linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent; a cycloalkoxy group having 3 to 10 carbon atoms which may have a substituent; or an acyl group having 1 to 20 carbon atoms which may have a substituent; It shall have the following. R 1 ~R 5 , R 6 ~R 10 , R 11 ~R 15 , R 16 ~R 20 adjacent groups may be bonded to each other to form a ring, and R 5 and R 6 and R 15 and R 16 may be bonded to each other to form a ring.

[0012] [ka]

[0013] [In the formula, R 21 ~R 26 are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent; a linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent; a linear or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent; a cycloalkyl group having 3 to 10 carbon atoms which may have a substituent; a linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent; a cycloalkoxy group having 3 to 10 carbon atoms which may have a substituent; a thio group having 1 to 18 carbon atoms which may have a substituent; an amino group having 1 to 20 carbon atoms which may have a substituent; an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent; or a heterocyclic group having 5 to 36 ring atoms which may have a substituent, R 21 and R 22 , R 23 and R 24 and R 25 and R 26 may be bonded to each other to form a ring. Y 1 represents an oxygen atom, a sulfur atom, or a selenium atom, and m and n each represent an integer of 0 to 2, provided that either m or n is 1 or 2.

[0014] 2. A compound in which m in the general formula (2) is 1.

[0015] 3. A hole transport material for a photoelectric conversion device, containing the compound described above.

[0016] 4. The hole transport material for a photoelectric conversion element, characterized by containing a compound represented by the following general formula (3):

[0017] [ka]

[0018] [In the formula, R 27 and R 28 are each independently nitrile groups, a linear or branched perfluoroalkyl group having 1 to 4 carbon atoms; a linear or branched acyl group having 1 to 18 carbon atoms which may have a substituent; a linear or branched alkoxycarbonyl group having 1 to 18 carbon atoms which may have a substituent; a thio group having 1 to 18 carbon atoms which may have a substituent; an amino group having 1 to 20 carbon atoms which may have a substituent; or a linear or branched alkylsulfonyl group having 1 to 18 carbon atoms which may have a substituent, R 27 and R 28 may be bonded to each other to form a ring. X 1 and X 2 are each independently represented by the general formula (2), R 29 ~R 32 are each independently an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent; Or it represents a heterocyclic group having 5 to 36 ring atoms which may have a substituent. R 29 and R 30 , R 31 and R 32 may be bonded to each other to form a ring.

[0019] 5. A hole transport material for a photoelectric conversion element, wherein the compound represented by the general formula (3) is represented by the following general formulas (4) to (6):

[0020] [ka]

[0021] [In the formula, R 27 and R 28 are each independently the same as defined above, and R 27 and R 28 may be bonded to each other to form a ring. X 1 and X 2 are each independently represented by the general formula (2), R 33 ~R 52 are each independently a hydrogen atom, a halogen atom, a trimethylsilyl group, a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent; a linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent; a linear or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent; a cycloalkyl group having 3 to 10 carbon atoms which may have a substituent; a linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent; a cycloalkoxy group having 3 to 10 carbon atoms which may have a substituent; an acyl group having 1 to 20 carbon atoms which may have a substituent; a thio group having 1 to 18 carbon atoms which may have a substituent; an amino group having 1 to 20 carbon atoms which may have a substituent; an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent; or a heterocyclic group having 5 to 36 ring atoms which may have a substituent, R 33 ~R 37 , R 38 ~R 42 , R 43 ~R 47 , R 48 ~R 52 Adjacent groups may be bonded to each other to form a ring.

[0022] [ka]

[0023] [In the formula, R 27 and R 28 are each independently the same as defined above, and R 27 and R 28 may be bonded to each other to form a ring. X 1 and X 2 are each independently represented by the general formula (2), R 33 ~R 52 are each independently the same as the substituents described above, R 33 ~R 36 , R 39 ~R 42, R 43 ~R 46 , R 49 ~R 52 Adjacent groups may be bonded to each other to form a ring.

[0024] [ka]

[0025] [In the formula, R 27 and R 28 are each independently the same as defined above, and R 27 and R 28 may be bonded to each other to form a ring. X 1 and X 2 are each independently represented by the general formula (2), R 33 ~R 52 are each independently the same as the substituents described above, R 33 ~R 36 , R 39 ~R 42 , R 43 ~R 46 , R 49 ~R 52 Adjacent groups may be bonded to each other to form a ring. Z 1 and Z 2 each independently represents an oxygen atom, a sulfur atom, or a selenium atom.

[0026] 6. A hole transport material for a photoelectric conversion element, characterized in that the content of the compound represented by the general formula (3) is 3 to 96 mass %.

[0027] 7. A hole transport material for a photoelectric conversion element, characterized in that the content of the compound represented by general formula (3) is 50 to 94 mass %.

[0028] 8. A photoelectric conversion element using the hole transport material for photoelectric conversion elements described above.

[0029] 9. A solar cell using the photoelectric conversion element according to claim 7. [Effects of the Invention]

[0030] According to the hole transport material for a photoelectric conversion element of the present invention, it is possible to provide a hole transport material for a photoelectric conversion element that achieves excellent photoelectric conversion efficiency, and a photoelectric conversion element and a solar cell using the same. [Brief explanation of the drawings]

[0031] [Figure 1] 1A and 1B are schematic cross-sectional views illustrating the configurations of photoelectric conversion elements according to examples of the present invention and comparative examples. DETAILED DESCRIPTION OF THE INVENTION

[0032] DETAILED DESCRIPTION OF THE INVENTION The hole transport layer material for a photoelectric conversion element of the present invention is used in a photoelectric conversion element.

[0033] <Photoelectric conversion element> The photoelectric conversion element of the present invention typically has a conductive support (electrode) 1, an electron transport layer 2, a photoelectric conversion layer 3, an intermediate layer 4, a hole transport layer 5, and a counter electrode 6, as shown in the schematic cross-sectional view of FIG.

[0034] The compound represented by formula (1) contained in the hole transport material for a photoelectric conversion element will be specifically explained below, but the present invention is not limited thereto.

[0035] In general formula (1), R 1 ~R 20 are each independently a hydrogen atom, a halogen atom, a carboxyl group, a trimethylsilyl group, a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent; a linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent; a linear or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent; a cycloalkyl group having 3 to 10 carbon atoms which may have a substituent; a linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent; a cycloalkoxy group having 3 to 10 carbon atoms which may have a substituent; an acyl group having 1 to 20 carbon atoms which may have a substituent; a thio group having 1 to 18 carbon atoms which may have a substituent; an amino group having 1 to 20 carbon atoms which may have a substituent; an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent; Alternatively, it represents a heterocyclic group having 5 to 36 ring atoms which may have a substituent.

[0036] In the present invention, the term "halogen atom" includes fluorine, chlorine, bromine and iodine.

[0037] In general formula (1), R 1 ~R 20 Specific examples of the "straight-chain or branched alkyl group having 1 to 20 carbon atoms" in the "straight-chain or branched alkyl group having 1 to 20 carbon atoms which may have a substituent" represented by the formula (1) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, an n-hexyl group, a 2-ethylhexyl group, a heptyl group, an octyl group, an isooctyl group, a nonyl group, and a decyl group.

[0038] In general formula (1), R 1 ~R 20Specific examples of the "straight-chain or branched alkenyl group having 2 to 20 carbon atoms" in the "straight-chain or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent" represented by the formula (1) include ethenyl group (vinyl group), 1-propenyl group, 2-propenyl group (allyl group), 1-methylethenyl group, 1-butenyl group, 2-butenyl group, 1-pentenyl group, 1-hexenyl group, 2-methyl-1-propenyl group, 2-methyl-2-propenyl group, 1-ethylethenyl group, and straight-chain or branched alkenyl groups having 2 to 20 carbon atoms in which a plurality of these alkenyl groups are bonded.

[0039] In general formula (1), R 1 ~R 20 Specific examples of the "straight-chain or branched alkynyl group having 2 to 20 carbon atoms" in the "straight-chain or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent" represented by the formula (1) include an ethynyl group, a 1-propynyl group, a 2-propynyl group, a 1-butynyl group, a 2-butynyl group, a 1-methyl-2-propynyl group, a 1-pentynyl group, a 2-pentynyl group, a 1-methyl-n-butynyl group, a 2-methyl-n-butynyl group, a 3-methyl-n-butynyl group, and a 1-hexynyl group.

[0040] In general formula (1), R 1 ~R 20 Specific examples of the "cycloalkyl group having 3 to 10 carbon atoms" in the "cycloalkyl group having 3 to 10 carbon atoms which may have a substituent" represented by the formula (1) include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecyl group, a cyclododecyl group, a 4-methylcyclohexyl group, and a 4-ethylcyclohexyl group.

[0041] In general formula (1), R 1 ~R 20Specific examples of the "straight-chain or branched alkoxy group having 1 to 20 carbon atoms" in the "straight-chain or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent" represented by the formula (1) include a methoxy group, an ethoxy group, a propoxy group, an n-butoxy group, an n-pentyloxy group, an n-hexyloxy group, a heptyloxy group, an octyloxy group, a nonyloxy group, a decyloxy group, an isopropoxy group, an isobutoxy group, an s-butoxy group, a t-butoxy group, an isooctyloxy group, a t-octyloxy group, a phenoxy group, a tolyloxy group, a biphenylyloxy group, a terphenylyloxy group, a naphthyloxy group, an anthryloxy group, a phenanthryloxy group, a fluorenyloxy group, and an indenyloxy group.

[0042] In general formula (1), R 1 ~R 20 Specific examples of the "straight-chain or branched cycloalkoxy group having 3 to 10 carbon atoms" in the "straight-chain or branched cycloalkoxy group having 3 to 10 carbon atoms which may have a substituent" represented by the formula (1) include a cyclopropoxy group, a cyclobutoxy group, a cyclopentyloxy group, a cyclohexyloxy group, and a 4-methylcyclohexyloxy group.

[0043] In general formula (1), R 1 ~R 20 Specific examples of the "acyl group having 1 to 20 carbon atoms" in the "acyl group having 1 to 20 carbon atoms which may have a substituent" represented by the formula (1) include an acetyl group, a propionyl group, a butyryl group, an isobutyryl group, a valeryl group, an isovaleryl group, a benzoylacetyl group, and a benzoyl group.

[0044] In general formula (1), R 1 ~R 20 Specific examples of the "thio group having 1 to 18 carbon atoms" in the "thio group having 1 to 18 carbon atoms which may have a substituent" represented by the following formula include a methylthio group, an ethylthio group, a propylthio group, a phenylthio group, and a biphenylthio group.

[0045] In general formula (1), R 1 ~R 20 Specific examples of the "amino group having 1 to 20 carbon atoms" in the "amino group having 1 to 20 carbon atoms which may have a substituent" represented by the formula (1) include monosubstituted amino groups such as an ethylamino group, an acetylamino group, and a phenylamino group, and disubstituted amino groups such as a diethylamino group, a diphenylamino group, and an acetylphenylamino group.

[0046] In general formula (1), R 1 ~R 20 Specific examples of the "aromatic hydrocarbon group having 6 to 36 carbon atoms" in the "aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent" represented by the formula (1) include a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a biphenyl group, an anthracenyl group (anthryl group), a phenanthryl group, a fluorenyl group, an indenyl group, a pyrenyl group, a perylenyl group, a fluoranthenyl group, a triphenylenyl group, etc. In the present invention, the aromatic hydrocarbon group includes a "condensed polycyclic aromatic group".

[0047] In general formula (1), R 1 ~R 20 Specific examples of the "heterocyclic group having 5 to 36 ring atoms" in the "heterocyclic group having 5 to 36 ring atoms which may have a substituent" represented by the formula (I) include a pyridyl group, a pyrimidinyl group, a triazinyl group, a thienyl group, a furyl group (furanyl group), a pyrrolyl group, an imidazolyl group, a pyrazolyl group, a triazolyl group, a quinolyl group, an isoquinolyl group, a naphthyldinyl group, an acridinyl group, a phenanthrolinyl group, a benzofuranyl group, a benzothienyl group, an oxazolyl group, an indolyl group, a carbazolyl group, a benzoxazolyl group, a thiazolyl group, a benzothiazolyl group, a quinoxalinyl group, a benzimidazolyl group, a pyrazolyl group, a dibenzofuranyl group, a dibenzothienyl group, and a carbonyl group.

[0048] In general formula (1), R 1 ~R 20Examples of the "substituent" in the "optionally substituted linear or branched alkyl group of 1 to 18 carbon atoms," "optionally substituted linear or branched alkenyl group of 2 to 20 carbon atoms," "optionally substituted linear or branched alkynyl group of 2 to 20 carbon atoms," "optionally substituted cycloalkyl group of 3 to 10 carbon atoms," "optionally substituted alkoxy group of 1 to 20 carbon atoms," "optionally substituted linear or branched cycloalkoxy group of 3 to 10 carbon atoms," "optionally substituted acyl group of 1 to 20 carbon atoms," "optionally substituted thio group of 1 to 18 carbon atoms," "optionally substituted amino group of 1 to 20 carbon atoms," "optionally substituted aromatic hydrocarbon group of 6 to 36 carbon atoms," or "optionally substituted heterocyclic group of 5 to 36 ring atoms," represented by the formula (I) include specifically halogen atoms such as fluorine atom, chlorine atom, bromine atom, and iodine atom; cyano group; hydroxyl group; nitro group; nitroso group; carboxyl group; phosphate group; Carboxylic acid ester groups such as methyl ester groups and ethyl ester groups; thioxo groups (>C=S); linear or branched alkyl groups having 1 to 18 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, isopentyl, n-hexyl, 2-ethylhexyl, heptyl, octyl, isooctyl, nonyl, and decyl; linear or branched alkenyl groups having 2 to 20 carbon atoms, such as ethenyl (vinyl), 1-propenyl, 2-propenyl (allyl), 1-butenyl, 2-butenyl, 1-pentenyl, 1-hexenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl, and 1-ethylethenyl; linear or branched alkoxy groups having 1 to 18 carbon atoms, such as a methoxy group, an ethoxy group, a propoxy group, a t-butoxy group, a pentyloxy group, or a hexyloxy group; Aromatic hydrocarbon groups having 6 to 30 carbon atoms, such as phenyl, naphthyl, anthryl, phenanthryl, and pyrenyl groups; heterocyclic groups having 5 to 30 ring atoms, such as a pyridyl group, a pyrimidinyl group, a triazinyl group, a thienyl group, a furyl group (a furanyl group), a pyrrolyl group, an imidazolyl group, a pyrazolyl group, a triazolyl group, a quinolyl group, an isoquinolyl group, a naphthyldinyl group, an acridinyl group, a phenanthrolinyl group, a benzofuranyl group, a benzothienyl group, an oxazolyl group, an indolyl group, a carbazolyl group, a benzoxazolyl group, a thiazolyl group, a benzothiazolyl group, a quinoxalinyl group, a benzimidazolyl group, a pyrazolyl group, a dibenzofuranyl group, a dibenzothienyl group, or a carbonylyl group; an amino group having 0 to 18 carbon atoms, which may be an unsubstituted amino group (-NH2), a monosubstituted amino group such as an ethylamino group, an acetylamino group, or a phenylamino group, or a disubstituted amino group such as a diethylamino group, a diphenylamino group, or an acetylphenylamino group; Thio groups having 0 to 18 carbon atoms, such as unsubstituted thio groups (thiol groups: —SH), methylthio groups, ethylthio groups, propylthio groups, phenylthio groups, and biphenylthio groups; These "substituents" may be present in only one or more, and when present in more than one, they may be the same or different. Furthermore, these "substituents" may further have the substituents exemplified above.

[0049] In general formula (1), R 1 ~R 20 has at least one Halogen atoms, carboxyl groups, trimethylsilyl groups, a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent; a linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent; a linear or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent; a cycloalkyl group having 3 to 10 carbon atoms which may have a substituent; a linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent; a cycloalkoxy group having 3 to 10 carbon atoms which may have a substituent; Alternatively, it has an acyl group having 1 to 20 carbon atoms which may have a substituent.

[0050] In general formula (1), R 1 ~R 20 is preferably a hydrogen atom, a linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent, or an amino group having 1 to 20 carbon atoms which may have a substituent.

[0051] In general formula (1), R 1 ~R 20 represents a substituent as described above, except that R 1 ~R 5 , R 6 ~R 10 , R 11 ~R 15 , R 16 ~R 20 adjacent groups may be bonded to each other via a single bond, a bond via an oxygen atom, a sulfur atom, a selenium atom, or a bond via a nitrogen atom to form a ring, and R 5 and R 6 and R 15 and R 16 may be bonded to each other via a single bond, a bond via an oxygen atom, a sulfur atom, a selenium atom, or a bond via a nitrogen atom to form a ring, and are preferably bonded via a single bond, an oxygen atom, or a sulfur atom.

[0052] In general formula (1), X 1 and X 2 is preferably represented by general formula (2).

[0053] In general formula (2), R 21 ~R 26 are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent; a linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent; a linear or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent; a cycloalkyl group having 3 to 10 carbon atoms which may have a substituent; a linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent; a cycloalkoxy group having 3 to 10 carbon atoms which may have a substituent; a thio group having 1 to 18 carbon atoms which may have a substituent; an amino group having 1 to 20 carbon atoms which may have a substituent; an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent; Or it represents a heterocyclic group having 5 to 36 ring atoms which may have a substituent.

[0054] In general formula (2), R 21 ~R 26 In the "straight-chain or branched alkyl group having 1 to 20 carbon atoms which may have a substituent" represented by the formula (1), the "straight-chain or branched alkyl group having 1 to 20 carbon atoms" is, for example, 1 ~R 20 Examples of the alkyl group include the same as the "straight or branched alkyl group having 1 to 20 carbon atoms which may have a substituent" represented by the following formula:

[0055] In general formula (2), R 21 ~R 26 The "straight-chain or branched alkenyl group having 2 to 20 carbon atoms" in the "straight-chain or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent" represented by the formula (1) includes, for example, 1 ~R 20 Examples of the alkyl group include the same as the "straight or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent" represented by the following formula:

[0056] In general formula (2), R 21 ~R 26The "straight-chain or branched alkynyl group having 2 to 20 carbon atoms" in the "straight-chain or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent" represented by the general formula (1) includes R 1 ~R 20 Examples of the alkynyl group include the same as the "straight or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent" represented by the following formula:

[0057] In general formula (2), R 21 ~R 26 The "cycloalkyl group having 3 to 10 carbon atoms" in the "cycloalkyl group having 3 to 10 carbon atoms which may have a substituent" represented by the formula (1) is, for example, R 1 ~R 20 Examples of the cycloalkyl group include the same as the "cycloalkyl group having 3 to 10 carbon atoms which may have a substituent" represented by the following formula:

[0058] In general formula (2), R 21 ~R 26 In the "straight-chain or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent" represented by the formula (1), the "straight-chain or branched alkoxy group having 1 to 20 carbon atoms" includes, in general formula (1), R 1 ~R 20 Examples of the alkoxy group include the same as the "straight-chain or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent" represented by the following formula:

[0059] In general formula (2), R 21 ~R 26 The "cycloalkoxy group having 3 to 10 carbon atoms" in the "cycloalkoxy group having 3 to 10 carbon atoms which may have a substituent" represented by the following general formula (1) is R 1 ~R 20 Examples of the cycloalkoxy group include the same as the "cycloalkoxy group having 3 to 10 carbon atoms which may have a substituent" represented by the following formula:

[0060] In general formula (2), R 21 ~R26 The "thio group having 1 to 18 carbon atoms" in the "thio group having 1 to 18 carbon atoms which may have a substituent" represented by the following general formula (1) is R 1 ~R 20 Examples thereof include the same as the "thio group having 1 to 18 carbon atoms which may have a substituent" represented by the following formula:

[0061] In general formula (2), R 21 ~R 26 The "amino group having 1 to 20 carbon atoms" in the "amino group having 1 to 20 carbon atoms which may have a substituent" represented by the general formula (1) is, for example, R 1 ~R 20 Examples of the amino group include the same as the "amino group having 1 to 20 carbon atoms which may have a substituent" represented by the following formula:

[0062] In general formula (2), R 21 ~R 26 The "aromatic hydrocarbon group having 6 to 36 carbon atoms" in the "aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent" represented by the formula (1) is, for example, R 1 ~R 20 Examples of the aromatic hydrocarbon group include the same as the "optionally substituted aromatic hydrocarbon group having 6 to 36 carbon atoms" represented by the following formula:

[0063] In general formula (2), R 21 ~R 26 In the "heterocyclic group having 5 to 36 ring atoms which may have a substituent" represented by the general formula (1), the "heterocyclic group having 5 to 36 ring atoms" represented by the general formula (1) is R 1 ~R 20 Examples of the heterocyclic group include the same as the "heterocyclic group having 5 to 36 ring atoms which may have a substituent" represented by the following formula:

[0064] In general formula (2), R 21 ~R 26Examples of the "substituent" in the "optionally substituted linear or branched alkyl group of 1 to 18 carbon atoms," "optionally substituted linear or branched alkenyl group of 2 to 20 carbon atoms," "optionally substituted linear or branched alkynyl group of 2 to 20 carbon atoms," "optionally substituted cycloalkyl group of 3 to 10 carbon atoms," "optionally substituted alkoxy group of 1 to 20 carbon atoms," "optionally substituted linear or branched cycloalkoxy group of 3 to 10 carbon atoms," "optionally substituted acyl group of 1 to 20 carbon atoms," "optionally substituted thio group of 1 to 18 carbon atoms," "optionally substituted amino group," "optionally substituted aromatic hydrocarbon group of 6 to 36 carbon atoms," or "optionally substituted heterocyclic group of 5 to 36 ring atoms" represented by the general formula (1) include R 1 ~R 20 Examples of the "substituent" include the same as those in the "straight-chain or branched alkyl group having 1 to 18 carbon atoms which may have a substituent" represented by the following formula:

[0065] In general formula (2), R 21 and R 22 , R 23 and R 24 and R 25 and R 26 may be bonded to each other via a single bond, a bond via an oxygen atom, a sulfur atom, a selenium atom, or a bond via a nitrogen atom to form a ring.

[0066] In general formula (2), Y 1 represents a bond via an oxygen atom, a sulfur atom, or a selenium atom.

[0067] In general formula (2), m and n each represent an integer of 0 to 2; when m is 0, n is 1 to 2; when n is 0, m is 1 to 2; and when either m or n is 1 or 2, the case where both are 0 is not included. m is preferably 1. In addition, the cyclopentadithiophene moiety, which is the central skeleton of general formula (1), may be bonded to either the phenyl group or the 5-membered heterocyclic group represented by general formula (2).

[0068] In general formula (2), it is preferable that m is 1 and n is 0 or 1. When m is 1 and n is 1 in general formula (2), it is preferable that a 5-membered heterocyclic group is bonded to the cyclopentadithiophene portion, which is the central skeleton of general formula (1).

[0069] Specific examples of the compound represented by the general formula (1) of the present invention are shown below, but the present invention is not limited to these. Furthermore, the following exemplary compounds are shown with some hydrogen atoms, carbon atoms, etc. omitted, and are examples of possible isomers, but all other isomers are included. Furthermore, each may be a mixture of two or more isomers.

[0070] [ka]

[0071] [ka]

[0072] [ka]

[0073] [ka]

[0074] [ka]

[0075] [ka]

[0076] [ka]

[0077] [ka]

[0078] [ka]

[0079] [ka]

[0080] [ka]

[0081] [ka]

[0082] [ka]

[0083] The compound represented by the general formula (1) can be used as a hole transport material for a photoelectric conversion element.

[0084] In the present invention, the hole transport material for a photoelectric conversion element may be a combination of one or more compounds represented by the general formula (1), or may be a combination of other hole transport materials not belonging to the present invention. In the present invention, when the compound represented by the general formula (1) is used in combination with other materials, it is preferable to use it in combination with a compound represented by the general formula (3), and it is more preferable to use it in combination with a compound represented by the general formula (4), the general formula (5), or the general formula (6).

[0085] The compounds represented by formula (3) will be specifically explained below, but the present invention is not limited to these.

[0086] In general formula (3), R 27 and R 28 are each independently nitrile groups, a linear or branched perfluoroalkyl group having 1 to 4 carbon atoms; a linear or branched acyl group having 1 to 18 carbon atoms which may have a substituent; a linear or branched alkoxycarbonyl group having 1 to 18 carbon atoms which may have a substituent; a thio group having 1 to 18 carbon atoms which may have a substituent; an amino group having 1 to 20 carbon atoms which may have a substituent; Alternatively, it represents a linear or branched alkylsulfonyl group having 1 to 18 carbon atoms which may have a substituent.

[0087] In general formula (3), R 27 and R 28 Specific examples of the "straight-chain or branched perfluoroalkyl group having 1 to 4 carbon atoms" represented by the formula (1) include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, and the like, in which hydrogen atoms in a straight-chain or branched alkyl group having 1 to 4 carbon atoms have been completely substituted with fluorine atoms (perfluorinated).

[0088] In general formula (3), R 27and R 28 Specific examples of the "acyl group having 1 to 20 carbon atoms" in the "acyl group having 1 to 20 carbon atoms which may have a substituent" represented by the formula (1) include an acetyl group, a propionyl group, a butyryl group, an isobutyryl group, a valeryl group, an isovaleryl group, a benzoylacetyl group, a benzoyl group, etc., and when it contains an alkyl chain, it includes one in which all hydrogen atoms are substituted with fluorine atoms (perfluorinated). It may also be one bonded to an amino group (-CO-N<).

[0089] In general formula (3), R 27 and R 28 Specific examples of the "straight-chain or branched alkoxycarbonyl group having 1 to 18 carbon atoms" in the "straight-chain or branched alkoxycarbonyl group having 1 to 18 carbon atoms which may have a substituent" represented by the formula (1) include a methoxycarbonyl group, an ethoxycarbonyl group, etc., and when it contains an alkyl chain, it also includes those in which hydrogen atoms are completely substituted with fluorine atoms (perfluorinated).

[0090] In general formula (3), R 27 and R 28 Specific examples of the "thio group having 1 to 18 carbon atoms" in the "thio group having 1 to 18 carbon atoms which may have a substituent" represented by the formula (1) include a methylthio group, an ethylthio group, a propylthio group, a phenylthio group, and a biphenylthio group.

[0091] In general formula (3), R 27 and R 28 Specific examples of the "amino group having 1 to 20 carbon atoms" in the "amino group having 1 to 20 carbon atoms which may have a substituent" represented by the formula (1) include monosubstituted amino groups such as an ethylamino group, an acetylamino group, and a phenylamino group, and disubstituted amino groups such as a diethylamino group, a diphenylamino group, and an acetylphenylamino group.

[0092] In general formula (3), R 27 and R 28Specific examples of the "straight-chain or branched alkylsulfonyl group having 1 to 18 carbon atoms" in the "straight-chain or branched alkylsulfonyl group having 1 to 18 carbon atoms which may have a substituent" represented by the formula: 1 (A 1 represents a linear or branched alkyl group having 1 to 20 carbon atoms which may have the above-mentioned substituents, and A 1 Examples of the alkyl group include the methyl group, ethyl group, n-propyl group, n-butyl group, and the like, which are given as examples of the linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent.

[0093] In general formula (3), R 27 and R 28 Examples of the "substituent" in the "optionally substituted acyl group having 1 to 20 carbon atoms," "optionally substituted linear or branched alkoxycarbonyl group having 1 to 18 carbon atoms," "optionally substituted thio group having 1 to 18 carbon atoms," "optionally substituted amino group having 1 to 20 carbon atoms," and "optionally substituted linear or branched alkylsulfonyl group having 1 to 18 carbon atoms" represented by the formula (1) include R 1 ~R 20 Examples of the "substituent" include the same as those in the "straight-chain or branched alkyl group having 1 to 18 carbon atoms which may have a substituent" represented by the following formula:

[0094] In general formula (3), R 27 and R 28 are each independently a nitrile group, a linear or branched acyl group having 1 to 18 carbon atoms which may have a substituent, or a linear or branched alkoxycarbonyl group having 1 to 18 carbon atoms which may have a substituent. 27 and R 28 may be a nitrile group. 1 is a nitrile group, and R 2may be a linear or branched alkoxycarbonyl group having 1 to 18 carbon atoms which may have a substituent. 27 and R 28 may be a linear or branched alkoxycarbonyl group having 1 to 18 carbon atoms which may have a substituent. 27 and R 28 are linear or branched acyl groups having 1 to 18 carbon atoms which may have a substituent, and which may be bonded to each other to form a ring.

[0095] In general formula (3), R 27 and R 28 may be bonded to each other via a single bond, a bond via an oxygen atom, a sulfur atom or a selenium atom, or a bond via a nitrogen atom to form a ring, and in this case, in the present invention, it is preferable that the ring is formed via a single bond.More preferably, it is an acidic heterocycle such as a barbituric acid type, a thiobarbituric acid type, a rhodanine type, a thiohydantoin type, or an indandione type.

[0096] In general formula (3), X 1 and X 2 can each independently be the same as those represented by the general formula (2).

[0097] In general formula (3), R 29 ~R 32 are each independently an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent; Or it represents a heterocyclic group having 5 to 36 ring atoms which may have a substituent.

[0098] In general formula (3), R 29 ~R 32 The "aromatic hydrocarbon group having 6 to 36 carbon atoms" in the "aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent" represented by the formula (1) is, for example, R 1 ~R 20Examples of the aromatic hydrocarbon group include the same as the "optionally substituted aromatic hydrocarbon group having 6 to 36 carbon atoms" represented by the following formula:

[0099] In general formula (3), R 29 ~R 32 In the "heterocyclic group having 5 to 36 ring atoms which may have a substituent" represented by the general formula (1), the "heterocyclic group having 5 to 36 ring atoms" represented by the general formula (1) is R 1 ~R 20 Examples of the heterocyclic group include the same as the "heterocyclic group having 5 to 36 ring atoms which may have a substituent" represented by the following formula:

[0100] In general formula (3), R 29 ~R 32 Examples of the "substituent" in the "optionally substituted aromatic hydrocarbon group having 6 to 36 carbon atoms" and the "optionally substituted heterocyclic group having 5 to 36 ring atoms" include, in general formula (1), R 1 ~R 20 Examples of the "substituent" include the same as those in the "straight-chain or branched alkyl group having 1 to 18 carbon atoms which may have a substituent" represented by the following formula:

[0101] In general formula (3), R 29 and R 30 , R 31 and R 32 may be bonded to each other via a single bond, a bond via an oxygen atom, a sulfur atom or a selenium atom, or a bond via a nitrogen atom to form a ring.

[0102] The compound represented by general formula (3) is preferably represented by any of the general formulae (4) to (6).

[0103] In the general formulas (4) to (6), R 27 and R 28 are each independently "represented by general formula (3)," 27 and R 28 " is represented by a group similar to ".

[0104] In the general formulas (4) to (6), X 1 and X 2 are each independently "represented by general formula (3)," X 1 and X 2 " is represented by the general formula (2) above.

[0105] In the general formulas (4) to (6), R 33 ~R 52 are each independently hydrogen atom, halogen atom, trimethylsilyl group, a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent; a linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent; a linear or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent; a cycloalkyl group having 3 to 10 carbon atoms which may have a substituent; a linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent; a cycloalkoxy group having 3 to 10 carbon atoms which may have a substituent; an acyl group having 1 to 20 carbon atoms which may have a substituent; a thio group having 1 to 18 carbon atoms which may have a substituent; an amino group having 1 to 20 carbon atoms which may have a substituent; an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent; Or it represents a heterocyclic group having 5 to 36 ring atoms which may have a substituent.

[0106] In the general formulas (4) to (6), R 33 ~R 52 In the "straight-chain or branched alkyl group having 1 to 20 carbon atoms which may have a substituent" represented by the formula (1), the "straight-chain or branched alkyl group having 1 to 20 carbon atoms" is, for example, 1 ~R 20Examples of the alkyl group include the same as the "straight or branched alkyl group having 1 to 20 carbon atoms which may have a substituent" represented by the following formula:

[0107] In the general formulas (4) to (6), R 33 ~R 52 The "straight-chain or branched alkenyl group having 2 to 20 carbon atoms" in the "straight-chain or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent" represented by the formula (1) includes, for example, 1 ~R 20 Examples of the alkyl group include the same as the "straight or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent" represented by the following formula:

[0108] In the general formulas (4) to (6), R 33 ~R 52 The "straight-chain or branched alkynyl group having 2 to 20 carbon atoms" in the "straight-chain or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent" represented by the general formula (1) includes R 1 ~R 20 Examples of the alkynyl group include the same as the "straight or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent" represented by the following formula:

[0109] In the general formulas (4) to (6), R 33 ~R 52 The "cycloalkyl group having 3 to 10 carbon atoms" in the "cycloalkyl group having 3 to 10 carbon atoms which may have a substituent" represented by the formula (1) is, for example, R 1 ~R 20 Examples of the cycloalkyl group include the same as the "cycloalkyl group having 3 to 10 carbon atoms which may have a substituent" represented by the following formula:

[0110] In the general formulas (4) to (6), R 33 ~R 52In the "straight-chain or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent" represented by the formula (1), the "straight-chain or branched alkoxy group having 1 to 20 carbon atoms" includes, in general formula (1), R 1 ~R 20 Examples of the alkoxy group include the same as the "straight-chain or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent" represented by the following formula:

[0111] In the general formulas (4) to (6), R 33 ~R 52 The "cycloalkoxy group having 3 to 10 carbon atoms" in the "cycloalkoxy group having 3 to 10 carbon atoms which may have a substituent" represented by the following general formula (1) is R 1 ~R 20 Examples of the cycloalkoxy group include the same as the "cycloalkoxy group having 3 to 10 carbon atoms which may have a substituent" represented by the following formula:

[0112] In the general formulas (4) to (6), R 33 ~R 52 The "thio group having 1 to 18 carbon atoms" in the "thio group having 1 to 18 carbon atoms which may have a substituent" represented by the following general formula (1) is R 1 ~R 20 Examples thereof include the same as the "thio group having 1 to 18 carbon atoms which may have a substituent" represented by the following formula:

[0113] In the general formulas (4) to (6), R 33 ~R 52 The "amino group having 1 to 20 carbon atoms" in the "amino group having 1 to 20 carbon atoms which may have a substituent" represented by the general formula (1) is, for example, R 1 ~R 20 Examples of the amino group include the same as the "amino group having 1 to 20 carbon atoms which may have a substituent" represented by the following formula:

[0114] In the general formulas (4) to (6), R 33 ~R 52The "aromatic hydrocarbon group having 6 to 36 carbon atoms" in the "aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent" represented by the formula (1) is, for example, R 1 ~R 20 Examples of the aromatic hydrocarbon group include the same as the "optionally substituted aromatic hydrocarbon group having 6 to 36 carbon atoms" represented by the following formula:

[0115] In the general formulas (4) to (6), R 33 ~R 52 In the "heterocyclic group having 5 to 36 ring atoms which may have a substituent" represented by the general formula (1), the "heterocyclic group having 5 to 36 ring atoms" represented by the general formula (1) is R 1 ~R 20 Examples of the heterocyclic group include the same as the "heterocyclic group having 5 to 36 ring atoms which may have a substituent" represented by the following formula:

[0116] In the general formulas (4) to (6), R 33 ~R 52 Examples of the "substituent" in the "optionally substituted linear or branched alkyl group of 1 to 18 carbon atoms," "optionally substituted linear or branched alkenyl group of 2 to 20 carbon atoms," "optionally substituted linear or branched alkynyl group of 2 to 20 carbon atoms," "optionally substituted cycloalkyl group of 3 to 10 carbon atoms," "optionally substituted alkoxy group of 1 to 20 carbon atoms," "optionally substituted linear or branched cycloalkoxy group of 3 to 10 carbon atoms," "optionally substituted acyl group of 1 to 20 carbon atoms," "optionally substituted thio group of 1 to 18 carbon atoms," "optionally substituted amino group," "optionally substituted aromatic hydrocarbon group of 6 to 36 carbon atoms," or "optionally substituted heterocyclic group of 5 to 36 ring atoms" represented by the general formula (1) include R 1 ~R 20 Examples of the "substituent" include the same as those in the "straight-chain or branched alkyl group having 1 to 18 carbon atoms which may have a substituent" represented by the following formula:

[0117] "R" in general formula (4) 33 ~R 37 , R 38 ~R 42 , R 43 ~R 47 , R 48 ~R 52 ", "R" in general formula (5) and general formula (6) 33 ~R 36 , R 39 ~R 42 , R 43 ~R 46 , R 49 ~R 52 " may be bonded to each other via a single bond, a bond via an oxygen atom, a sulfur atom or a selenium atom, or a bond via a nitrogen atom to form a ring.

[0118] Specific examples of the compound represented by the general formula (3) of the present invention are shown below, but the present invention is not limited to these. Furthermore, the following exemplary compounds are shown with some hydrogen atoms, carbon atoms, etc. omitted, and are examples of possible isomers, but all other isomers are included. Furthermore, each may be a mixture of two or more isomers.

[0119] [ka]

[0120] [ka]

[0121] [ka]

[0122] [ka]

[0123] [ka]

[0124] [ka]

[0125] [ka]

[0126] [ka]

[0127] [ka]

[0128] [ka]

[0129] [ka]

[0130] [ka]

[0131] The hole transport material for a photoelectric conversion element of the present invention represented by the general formula (1) can be synthesized by a known method. In the general formula (1), a synthesis example in which m in the general formula (2) is 1 and n is 0 is shown below.

[0132] They can be synthesized by Suzuki-Miyaura cross-coupling reaction between the dibromo compound represented by the following formula (7) and the boronic acid compounds represented by general formulas (8) and (9) or the boronic acid ester compounds represented by general formulas (10) and (11).

[0133] [ka]

[0134] [ka]

[0135] [ka]

[0136] The hole transport material for a photoelectric conversion element of the present invention represented by the above formula (7) can be synthesized by a known method. In the general formula (3), a synthesis example in which m in the general formula (2) is 1 and n is 0 is shown below.

[0137] The dibromo compound represented by general formula (3) can be synthesized by Suzuki-Miyaura cross-coupling reaction with boronic acid compounds represented by general formulas (12) and (13) or boronic ester compounds represented by general formulas (14) and (15), followed by Knoevenagel condensation reaction with the compound represented by general formula (16).

[0138] [ka]

[0139] [ka]

[0140] [ka]

[0141] The hole transport materials for photoelectric conversion elements represented by the general formulas (1) and (3) of the present invention can be purified by column chromatography, adsorption purification using silica gel, activated carbon, activated clay, etc., recrystallization or crystallization using a solvent, etc. Alternatively, it is effective to use a compound with increased purity by combining these methods. Furthermore, these compounds can be identified by nuclear magnetic resonance analysis (NMR).

[0142] The compound represented by general formula (3) is preferably mixed with the compound represented by general formula (1) and used as a hole transport material for a photoelectric conversion element. The content of the compound represented by general formula (3) is preferably 3 to 96 mass %, and more preferably 50 to 94 mass %. By using a mixture of the compound represented by general formula (1) and the compound represented by general formula (3), the advantages of the compound represented by general formula (1), which tends to have a high open-circuit voltage, and the advantage of the compound represented by general formula (3), which tends to have a high short-circuit current, are maintained, and better effects than when used alone can be expected.

[0143] Preferred embodiments of the photoelectric conversion element of the present invention will be described below.

[0144] As shown in FIG. 1, the photoelectric conversion element of the present invention preferably comprises a conductive support (electrode) 1, an electron transport layer 2, a photoelectric conversion layer 3, an intermediate layer 4, a hole transport layer 5, and a counter electrode 6, but is not limited thereto. Furthermore, the photoelectric conversion element of the present invention is preferably used as a solar cell, and is more preferably a perovskite-type photoelectric conversion element, but is not limited thereto. In the present invention, the perovskite-type photoelectric conversion element preferably comprises a conductive support (electrode) 1, an electron transport layer 2, a photoelectric conversion layer (perovskite layer) 3, an intermediate layer 4, a hole transport layer 5, and a counter electrode 6, in this order. Alternatively, the photoelectric conversion element may be configured in the order of the conductive support, the hole transport layer, the photoelectric conversion layer (perovskite layer), the electron transport layer, and the counter electrode.

[0145] <Conductive Support> In the photoelectric conversion element of the present invention, the conductive support must be translucent enough to transmit light that contributes to photoelectric conversion. Furthermore, since the conductive support is a member that functions to extract current from the photoelectric conversion layer, it is preferably a conductive substrate. Specific examples of conductive materials include conductive transparent oxide semiconductors such as tin-doped indium oxide (ITO), zinc-doped indium oxide (IZO), tungsten-doped indium oxide (IWO), zinc-aluminum oxide (AZO), fluorine-doped tin oxide (FTO), indium oxide (In2O3), and indium-tin composite oxide. However, amorphous oxides such as tin-doped indium oxide (ITO), zinc-doped indium oxide (IZO), and tungsten-doped indium oxide (IWO) are preferred.

[0146] Furthermore, the conductive support (transparent conductive layer) preferably has a sheet resistance of 100 Ω / □ or less, more preferably 50 Ω / □ or less, and more preferably 0.1 Ω / □ or more.

[0147] <Electron transport layer> In the photoelectric conversion element of the present invention, the electron transport layer 2 shown in FIG. 1 is a layer located between the conductive support (electrode) 1 and the photoelectric conversion layer 3, and it is preferable that the electron transport layer is formed on the conductive support (electrode) 1. The electron transport layer can be used to improve the efficiency of electron migration from the photoelectric conversion layer to the electrode while blocking the migration of holes. The form of the electron transport layer is not particularly limited, but it is preferably a thin film having a porous structure. The porous structure significantly increases the active surface area of ​​the photoelectric conversion layer, improving photoelectric conversion efficiency and providing an electron transport layer with excellent electron collection.

[0148] In the present invention, specific examples of the semiconductor that forms the electron transport layer include metal oxides such as titanium oxide (TiO2, etc.), tungsten oxide (WO2, WO3, W2O3, etc.), zinc oxide (ZnO), niobium oxide (Nb2O5, etc.), tantalum oxide (Ta2O5, etc.), yttrium oxide (YO3, etc.), strontium titanate (SrTiO3, etc.), and tin oxide (SnO, SnO2, SnO3, etc.); metal sulfides such as titanium sulfide, zinc sulfide, zirconium sulfide, copper sulfide, tin sulfide, indium sulfide, tungsten sulfide, cadmium sulfide, and silver sulfide; metal selenides such as titanium selenide, zirconium selenide, indium selenide, and tungsten selenide; and elemental semiconductors such as silicon and germanium. It is preferable to use one or more of these semiconductors. In the present invention, it is preferable to use one or more semiconductors selected from titanium oxide, zinc oxide, and tin oxide.

[0149] In the present invention, the paste containing the semiconductor fine particles may be a commercially available product, or a paste (electron transport layer coating liquid) prepared by dispersing commercially available semiconductor fine powder in a solvent may be used. Specific examples of solvents used in preparing the paste include, but are not limited to, water; alcoholic solvents such as methanol, ethanol, and isopropyl alcohol; ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; and hydrocarbon solvents such as n-hexane, cyclohexane, benzene, and toluene. These solvents may be used alone or in combination.

[0150] In the present invention, the semiconductor fine powder may be dispersed in a solvent after grinding the powder in a mortar or the like, or a dispersing machine such as a ball mill, a paint conditioner, a vertical bead mill, a horizontal bead mill, or an attritor may be used. When preparing a paste, it is preferable to add a surfactant or the like to prevent aggregation of the semiconductor fine particles, and it is also preferable to add a thickener such as polyethylene glycol to increase the viscosity.

[0151] In the present invention, the electron transport layer can be obtained using a known film-forming method depending on the material to be formed. The electron transport layer can be formed by any coating method using a coating liquid. Examples of the method include, but are not limited to, a method in which a paste containing semiconductor particles is applied to a conductive substrate by a wet coating method such as spin coating, inkjet printing, doctor blade printing, drop casting, squeegee printing, screen printing, reverse roll coating, gravure coating, kiss coating, roll brushing, spray coating, air knife coating, wire barber coating, pipe doctor printing, impregnation coating, or curtain coating, followed by baking to remove the solvent and additives, as well as sputtering, vapor deposition, electrodeposition, electrodeposition, and microwave irradiation. In the present invention, a spin coating method using the electron transport layer coating liquid prepared by the above method is preferably used to form a film, but is not limited thereto. The atmosphere in which the film is formed is not particularly limited and may be air.

[0152] The thickness of the electron transport layer is not particularly limited, but when a porous (mesoporous) metal oxide is used, it is usually preferably 20 to 200 nm or less, and more preferably 50 to 150 nm. In the present invention, when a dense electron transport layer is used instead of a mesoporous layer, the thickness of the electron transport layer is usually preferably 5 nm to 100 nm, and more preferably 10 nm to 50 nm. In addition, a non-crystalline (amorphous) thin film having no crystalline structure may be partially formed.

[0153] In the present invention, the film thickness of each layer can be measured by observing a cross section of the photoelectric conversion element using a scanning electron microscope (SEM) or the like.

[0154] <Photoelectric conversion layer> In the photoelectric conversion element of the present invention, it is preferable that a photoelectric conversion layer 3 is formed on the electron transport layer 2 shown in FIG.

[0155] In the present invention, when used as a perovskite-type photoelectric conversion element, the perovskite material of the photoelectric conversion layer represents a series of materials having a structure represented by the general formula ABX3, where A, B, and X represent an organic cation or a monovalent metal cation, a metal cation, and a halide anion, respectively. For example, A=Cs + , CH3NH3 + (MA), CH3CH2NH3 + (EA), NH=CHNH2 + Examples include (FA); B = Pb, Sn; X = Br, I. Specific examples include layers containing perovskite materials such as CH3NH3PbI3, C2H5NH3PbI3, CH3NH3PbBr3, C2H5NH3PbBr3, CH3NH3PbBr3, C2H5NH3PbCl3, CH3NH3PbCl3, C2H5NH3PbCl3, CsSnI3, CH3NH3SnI3, C2H5NH3SnI3, CsSnBr3, CH3NH3SnBr3, C2H5NH3SnBr3, CsSnCl3, CH3NH3SnCl3, C2H5NH3SnCl3, CsPbI2Br, and mixed cations expressed by any composition of (FA,MA)Pb(Br,I)3 (FA is formamide, MA is methylammonium) but are not limited to these. It is preferable to use one or more of these perovskite materials. In addition, a light absorbing agent other than the perovskite material may be contained.

[0156] Any coating method can be used to coat the photoelectric conversion layer (perovskite layer) of the photoelectric conversion element of the present invention with a coating liquid, and examples thereof include the same methods as those used to form the electron transport layer.

[0157] Commercially available materials may be used as the perovskite precursor. In the present invention, it is preferable to use a precursor of lead iodide (PbI), formamide iodide, methylammonium halide or ethylammonium halide, and cesium iodide (CsI), or a precursor of lead (II) iodide and cesium bromide in any composition, but the present invention is not limited to these.

[0158] From the viewpoint of precursor solubility, examples of the solvent for the perovskite precursor solution of the present invention include, but are not limited to, dimethyl sulfoxide, dimethylformamide, γ-butyrolactone, etc. These solvents may be used alone or in combination of two or more, and it is preferable to use a mixed solution of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO).

[0159] In the present invention, the atmosphere during film formation of the perovskite material is preferably a dry atmosphere, more preferably a dry inert gas atmosphere such as a glove box, from the viewpoint of preventing moisture contamination and enabling the reproducible production of high-efficiency perovskite solar cells. It is also preferable to perform dehydration and use a solvent with a low moisture content.

[0160] In the present invention, the temperature at which the photoelectric conversion layer (perovskite layer) is heated using a hot plate or the like is preferably 50 to 200° C., more preferably 70 to 190° C., from the viewpoint of producing a perovskite material from the precursor. The heating time is preferably about 10 to 90 minutes, more preferably about 10 to 60 minutes.

[0161] The thickness of the photoelectric conversion layer (perovskite layer) of the present invention is preferably 50 to 1000 nm, more preferably 300 to 700 nm, from the viewpoint of further suppressing performance degradation due to defects and peeling, and in order to ensure that the photoelectric conversion layer has sufficient light absorption rate and physical properties that do not result in an excessively high resistance value.

[0162] <Middle class> In the photoelectric conversion element of the present invention, the intermediate layer 4 shown in FIG. 1 is a layer that has the function of making the interlayer junction structure continuous and increasing the efficiency of charge transfer, and is a layer that is located between the photoelectric conversion layer and the hole transport layer.

[0163] In the present invention, it is preferable to use a compound having a quaternary ammonium salt structure in the intermediate layer, but this is not limitative and multiple compounds may be used in combination. Specific examples include phenylethylammonium bromide and n-hexyltrimethylammonium bromide.

[0164] The intermediate layer of the photoelectric conversion element of the present invention can be coated with a coating liquid by any coating method, including the same method as that for forming the electron transport layer. The film is preferably formed in a dry atmosphere. The solvent is preferably removed from the coating liquid by a reduced pressure method rather than a heating method.

[0165] The thickness of the intermediate layer is not particularly limited as long as it has the effect of increasing the efficiency of charge transfer, but is preferably 10 nm or less, more preferably 5 nm or less.

[0166] <Hole transport layer> In the photoelectric conversion element of the present invention, the hole transport layer 5 shown in FIG. 1 is a layer having a function of transporting holes and is located between the intermediate layer 4 and the counter electrode 6. The hole transport layer can be used to improve the efficiency of hole transport from the photoelectric conversion layer to the electrode while blocking the transport of electrons. For example, a conductor, a semiconductor, an organic hole transport material, etc. can be used for the hole transport layer, and an additive dopant (oxidizing agent) may be included to further improve the hole transport properties.

[0167] The hole transport layer of the present invention is a layer containing the compound represented by the general formula (1) as a hole transport material, or may be a layer containing the compound represented by the general formula (1) and the compound represented by the general formula (3). Photoelectric conversion elements and solar cells that achieve excellent photoelectric conversion efficiency can be constructed by using a compound represented by general formula (1) in a hole transport layer, or by using a hole transport layer containing a compound represented by general formula (1) and a compound represented by general formula (3). Furthermore, photoelectric conversion elements and solar cells that can achieve stable photoelectric conversion efficiency without undergoing any post-treatment steps such as aging after device fabrication can be constructed by using a compound represented by general formula (1) in a hole transport layer, or by using a hole transport layer containing a compound represented by general formula (1) and a compound represented by general formula (3). A hole transport material for photoelectric conversion elements that achieves stable photoelectric conversion efficiency without undergoing any post-treatment steps such as aging after device fabrication, and photoelectric conversion elements and solar cells that use the same can be constructed. In the hole transport layer of the present invention, one or more compounds represented by the general formula (1) and the general formula (3) may be used in combination, and they may also be used in combination with other hole transport materials not belonging to the present invention.

[0168] Specific examples of other hole transport materials that do not belong to the hole transport material of the present invention include, for example, compound semiconductors containing monovalent copper, such as CuI, CuInSe2, and CuS; and compounds containing metals other than copper, such as GaP, NiO, CoO, FeO, Bi2O3, MoO2, and Cr2O3. These metal oxides may be mixed in the hole transport layer or may be laminated on the hole transport material. Examples of organic hole transport materials include polythiophene derivatives such as poly-3-hexylthiophene (P3HT) and polyethylenedioxythiophene (PEDOT); fluorene derivatives such as 2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (Spiro-OMeTAD); carbazole derivatives such as polyvinylcarbazole; triphenylamine derivatives such as poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA); diphenylamine derivatives; polysilane derivatives; and polyaniline derivatives.

[0169] The hole transport layer of the present invention is preferably formed by coating and drying on the intermediate layer. Specific examples of the film formation method include spin coating, screen printing, roll coating, dip coating, spraying, knife coating, bar coating, die coating, and curtain coating, and spin coating is preferred in the present invention. The spin coating conditions can be appropriately set.

[0170] In the present invention, the solvent used in the coating solution for the hole transport layer (or the mixed coating solution for the hole transport layer) during film formation may be an aromatic organic solvent such as benzene, toluene, xylene, mesitylene, tetralin (1,2,3,4-tetrahydronaphthalene), monochlorobenzene (chlorobenzene), o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, or nitrobenzene; an alkyl halide organic solvent such as dichloromethane, chloroform, 1,2-dichloroethane, 1,1,2-trichloroethane, or dichloromethane; a nitrile solvent such as benzonitrile or acetonitrile; or a tetrahydrofuran solvent such as benzonitrile or acetonitrile. Examples of suitable solvents include, but are not limited to, ether solvents such as furan, dioxane, diisopropyl ether, c-pentyl methyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol monomethyl ether; ester solvents such as ethyl acetate and propylene glycol monomethyl ether acetate; and alcohol solvents such as methanol, isopropanol, n-butanol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, cyclohexanol, and 2-n-butoxyethanol. These solvents may be used alone or in combination, and the solvent to be used can be selected based on the solvent structure. Aromatic organic solvents and halogenated alkyl organic solvents are particularly preferred.

[0171] In the present invention, the conditions for drying the hole transport layer after coating as described above are not particularly limited, but it is desirable to dry it to the extent that the solvent can be removed, and it is preferable to heat it at about 50 to 120°C using a hot plate or the like, and the heating time is preferably about 10 to 60 minutes.

[0172] In the present invention, the thickness of the hole transport layer is preferably 5 to 500 nm, more preferably 10 to 200 nm, and even more preferably 10 to 100 nm, from the viewpoint of further improving photoelectric conversion efficiency.

[0173] In the present invention, the atmosphere during film formation of the hole transport layer is preferably a dry atmosphere, from the viewpoint of preventing moisture contamination and enabling the production of highly efficient perovskite solar cells with good reproducibility. It is also preferable to perform dehydration and use a solvent with a low moisture content.

[0174] <Additives> In the present invention, the hole transport layer may contain a dopant (or an oxidizing agent) or a basic compound (or a basic additive) as an additive. Incorporating an additive into the hole transport layer and increasing the carrier concentration of the hole transport material in the hole transport layer (doping) leads to an improvement in the conversion efficiency of the photoelectric conversion element. In the present invention, when the hole transport layer contains a dopant and a basic additive as additives, the amount of the additive is preferably about 3.5 equivalents or less per equivalent of the hole transport material.

[0175] In the present invention, when a dopant is contained, specific examples of the dopant include tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine)cobalt(III) tri[bis(trifluoromethane)sulfonimide] (FK209), lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), silver bis(trifluoromethanesulfonyl)imide, NOSbF6, SbCl5, SbF5, etc. In the present invention, it is preferable to use lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), but the dopant is not limited thereto.

[0176] In the present invention, when a dopant is used, the amount of the dopant is preferably 2.0 equivalents or less, more preferably 0.5 equivalents or less, per equivalent of the hole transport material contained in the hole transport layer.

[0177] In the present invention, a basic compound (basic additive) may be contained as an additive in the hole transport layer. Specific examples of the basic compound contained in the present invention include 4-tert-butylpyridine (tBP), 2-picoline, and 2,6-lutidine. A basic compound is often used in combination with a dopant. In the present invention, it is also desirable to use a basic compound in combination with a dopant.

[0178] In the present invention, when a basic compound is used, it is preferably used in an amount of 5 equivalents or less per equivalent of the hole transport material of the present invention.

[0179] Opposite In the present invention, the counter electrode 6 shown in Fig. 1 is disposed opposite the conductive support and formed on the hole transport layer 5, thereby enabling exchange of charges with the hole transport layer. In the photoelectric conversion element of the present invention, it is preferable to provide a metal electrode as a counter electrode on the hole transport layer 5, but it is also possible to add an electron blocking layer made of an organic material or an inorganic compound semiconductor between the hole transport layer 5 and the counter electrode 6.

[0180] In the present invention, specific examples of materials used for the counter electrode include metals such as platinum, titanium, stainless steel, aluminum, gold, silver, nickel, magnesium, chromium, cobalt, and copper, or alloys thereof. Among these, it is preferable to use gold, silver, or a silver alloy, as it exhibits high electrical conductivity even in a thin film. Examples of silver alloys include silver-gold alloys, silver-copper alloys, silver-palladium alloys, silver-copper-palladium alloys, and silver-platinum alloys, which are less susceptible to sulfidation or chlorination and improve the stability of the thin film.

[0181] In the present invention, the counter electrode is preferably made of a material that can be formed by a method such as vapor deposition.

[0182] When a metal layer is used as the counter electrode, its thickness is preferably 10 nm or more, more preferably 50 nm or more, to ensure good conductivity. Furthermore, a metal layer having a visible light transmittance of 60% or more can be used as a transparent electrode. In this case, to maintain light transmittance, the thickness is preferably 15 nm or less, more preferably 10 nm or less.

[0183] In the photoelectric conversion element of the present invention, the conductive support serves as the cathode, and the counter electrode serves as the anode. It is preferable to irradiate light such as sunlight from the conductive support side. When irradiated with sunlight, the photoelectric conversion layer (perovskite layer) absorbs the light and enters an excited state, generating electrons and holes. These electrons move through the electron transport layer, and the holes move through the hole transport layer to the electrode, causing a current to flow, and the element functions as a photoelectric conversion element.

[0184] When evaluating the performance (characteristics) of the photoelectric conversion element of the present invention, the short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency are measured. The short-circuit current density is the current flowing between the output terminals when the output terminals are short-circuited. 2 The open-circuit voltage is the voltage between the output terminals when they are open. The fill factor is the maximum output (product of current and voltage) divided by the product of the short-circuit current density and the open-circuit voltage, and is mainly affected by the internal resistance. The photoelectric conversion efficiency is the ratio of maximum output (W) to 1cm 2 The value is calculated by dividing the light intensity (W) per unit area by 100 and expressing it as a percentage.

[0185] The photoelectric conversion element of the present invention can be applied to perovskite solar cells, various optical sensors, etc. The perovskite solar cell of the present invention can be obtained by arranging a required number of cells into a module and providing predetermined electrical wiring, the module being a photoelectric conversion element comprising, as a hole transport layer, a hole transport material for photoelectric conversion elements containing a compound represented by general formula (1) above, or a hole transport material for photoelectric conversion elements containing a compound represented by general formula (1) above and a compound represented by general formula (3) above.

[0186] Although the preferred embodiment has been described above, the present invention is not limited to this, and may be modified as appropriate within the scope of the present invention. [Example]

[0187] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. 1 The analysis was performed using a 1H-NMR (1H-NMR (JNM-ECZ400S / L1 nuclear magnetic resonance spectrometer manufactured by JEOL Ltd.)).

[0188] [Synthesis Example 1] Synthesis of Compound (A-1) 3,3'-Dibromo-5,5'-bis(trimethylsilyl)-2,2'-bithiophene (10.0 g, manufactured by TCI) was added to a reaction vessel and the atmosphere was replaced with argon. Dehydrated tetrahydrofuran (106 mL) was added and the mixture was cooled to -78 °C in a dry ice-acetone bath. A hexane solution of n-butyllithium (1.55 mol / L, 29.0 mL, manufactured by Kanto Chemical) was added dropwise. The mixture was then heated to -30 °C over 4 hours, and dimethylcarbamoyl chloride (1.2 mL, manufactured by TCI) was added. After stirring at -30 °C for 20 minutes, the mixture was gradually heated to 0 °C over 3 hours and then warmed to room temperature. Water (150 mL) was added, and the mixture was separated. The organic layer was washed with water (150 mL) and saturated brine (100 mL). The aqueous layer was extracted three times with chloroform (40 mL). The organic layer was dried over anhydrous magnesium sulfate, and the solvent was distilled off to obtain a crude red solid. This crude product was purified using a silica gel column (hexane / ethyl acetate = 97 / 3 (volume ratio)) to obtain the compound represented by the following formula (17) as a red solid (yield: 5.76 g, 80%).

[0189] A reaction vessel was charged with 3.5 g of a compound represented by the following formula (17) and 21 mL of tetrahydrofuran (THF) and cooled to below 5°C in an ice bath. N-Bromosuccinimide (4.9 g, manufactured by TCI) and 7 mL of N,N-dimethylformamide (DMF) were added in several portions. The mixture was then returned to room temperature and stirred for 2 hours. After completion of the reaction, the reaction solution was poured into a beaker containing 400 mL of water. After stirring for 30 minutes, the solution was filtered. The resulting solid was dried under reduced pressure at 70°C, yielding 3.53 g of a compound represented by the following formula (18) as a purple solid (yield: 97%).

[0190] 1 H-NMR (400MHz, CDCl3): δ(ppm)=7.00(2H).

[0191] [ka]

[0192] The compound of formula (18) (0.88 g), [4-[bis(4-methoxyphenyl)amino]phenyl]boronic acid (2.10 g, manufactured by TCI), tetrakis(triphenylphosphine)palladium(0) (0.12 g, manufactured by Kanto Chemical), potassium carbonate (0.90 g, manufactured by Kanto Chemical), toluene (13 mL), ethanol (4.5 mL), and water (4.5 mL) were added to a reaction vessel and degassed under reduced pressure. The mixture was heated under reflux for 6 hours under an argon atmosphere. After the reaction was completed, toluene (10 mL) and water (10 mL) were added. The mixture was separated, and the aqueous layer was extracted twice with toluene (20 mL). The organic layer was concentrated, and the crude product was purified using a silica gel column (toluene / acetone = 100 / 1 (volume ratio)). The residue was purified again using a silica gel column (toluene) to obtain a compound represented by the following formula (A-1) as a dark green powder (amount: 1.86 g, yield: 93%).

[0193] 1 H-NMR (400MHz, CDCl3): δ (ppm) = 3.80 (12H), 6.84 (8H), 6.90 (4H), 7.05 (2H), 7.08 (8H), 7.31 (4H).

[0194] [ka]

[0195] [Synthesis Example 2] Synthesis of Compound (A-8)

[0196] A reaction vessel was charged with 4-bromoanisole (10.60 g, manufactured by TCI), diphenylamine (8.72 g, manufactured by TCI), palladium acetate (0.015 g), sodium t-butoxide (11.90 g, manufactured by Kanto Chemical), tri-t-butylphosphine (0.017 g, manufactured by Kanto Chemical), and toluene (110 mL), and the mixture was degassed under reduced pressure. The mixture was heated under reflux for 3 hours under an argon atmosphere. After the reaction was completed, the mixture was cooled and subjected to suction filtration. The residue was washed with toluene (50 mL), and the filtrate was concentrated. The resulting crude product was purified using an amino silica gel column (toluene / hexane = 1 / 1 (volume ratio)) and then recrystallized (toluene / methanol) to obtain the compound represented by the following formula (19) as a white solid (yield: 11.02 g, 78%).

[0197] A reaction vessel was charged with 10.50 g of the compound represented by formula (19) below and 71 mL of THF, and the mixture was cooled to below 5°C. N-Bromosuccinimide (14.30 g, manufactured by TCI) was then added, and the mixture was stirred at below 5°C for 2 hours. After the reaction was completed, the reaction solution was poured into a beaker containing 300 mL of water. Toluene (100 mL) was then added. The mixture was separated, and the aqueous layer was extracted twice with 40 mL of toluene. The organic layer was dried over sodium sulfate and concentrated. The crude product was purified using a silica gel column (toluene / hexane = 1:1 (volume ratio)) to obtain the compound represented by formula (20) below as a yellow oil (yield: 16.50 g, 100%).

[0198] 1 H-NMR (400MHz, CDCl3): δ (ppm) = 3.80 (3H), 6.84 (2H), 6.89 (4H), 7.02 (2H), 7.30 (4H).

[0199] [ka]

[0200] A reaction vessel was charged with the compound of formula (20) (16.40 g), 4,4'-dimethoxydiphenylamine (2.90 g, manufactured by TCI), tris(dibenzylideneacetone)dipalladium(0) (0.68 g, manufactured by Kanto Chemical), sodium t-butoxide (3.67 g, manufactured by Kanto Chemical), 1,1'-bis(diphenylphosphino)ferrocene (0.56 g, manufactured by Kanto Chemical), and toluene (25 mL), and the mixture was degassed under reduced pressure. The mixture was heated and refluxed under argon for 4 hours. After the reaction was completed, the mixture was cooled to below 40°C and subjected to suction filtration. The residue was washed with toluene (50 mL), and the filtrate was concentrated. The crude product was purified using a silica gel column (toluene / hexane = 1 / 1 (volume ratio)) to obtain the compound represented by formula (21) below as a yellow solid (yield: 2.76 g, 38%).

[0201] A reaction vessel was charged with the compound of formula (21) (10.0 g) and anhydrous THF (130 mL) and degassed under reduced pressure. Under an argon atmosphere, the mixture was cooled to below -70°C in an acetone-dry ice bath. A solution of n-butyllithium in hexane (1.55 M, 17.0 mL, manufactured by Kanto Chemical Co., Inc.) was added dropwise in small amounts. After the addition was complete, the mixture was stirred at below -70°C for 1 hour, and then triisopropyl borate (6.0 mL, manufactured by TCI) was added dropwise. After the addition was complete, the mixture was gradually warmed to room temperature and stirred at room temperature for 1 hour. Water (55 mL) was added to the reaction mixture to terminate the reaction. The reaction mixture was separated, and the aqueous layer was extracted twice with toluene (40 mL). The organic layer was dried over sodium sulfate and concentrated. The crude product was purified using a silica gel column (toluene → THF) to obtain the compound represented by formula (22) as a yellow powder (yield: 5.75 g, 62%).

[0202] 1 H-NMR (400MHz, DMSO-d6): δ (ppm) = 3.67 (6H), 3.73 (3H), 6.75 (4H), 6.8-6.9 (8H), 6.98-7.02 (6H), 7.59 (2H), 7.75 (2H).

[0203] [ka]

[0204] A reaction vessel was charged with the compound of formula (18) (1.00 g), the compound of formula (22) (4.59 g), potassium carbonate (19.0 g, manufactured by Kanto Chemical Co., Inc.), tetrakis(triphenylphosphine)palladium(0) (0.15 mg, manufactured by Kanto Chemical Co., Inc.), and toluene (150 mL) and degassed. The mixture was then heated under reflux for 68 hours under an argon atmosphere. After the reaction was completed, the mixture was cooled to below 50°C and filtered through Celite. The residue was washed with toluene (100 mL), and the filtrate was concentrated. The crude product was subjected to silica gel column chromatography (toluene → toluene / acetone = 100 / 1 (volume ratio)). It was then purified again using a silica gel column (toluene / acetone = 100 / 1 (volume ratio)) to obtain the compound represented by formula (A-8) below as a dark green powder (yield: 1.34 g, 40%).

[0205] 1 H-NMR (400MHz, DMSO-d6): δ(ppm)=3.72(12H), 3.75(6H), 6.7-6.8(8H), 6.91(8H), 6.95(8H), 7.01(8H), 7.05(4H), 7.29(2H), 7.46(4H).

[0206] [ka]

[0207] [Synthesis Example 3] Synthesis of Compound (A-10) A reaction vessel was charged with 3,6-dibromocarbazole (5.0 g, manufactured by TCI), 1-chloro-4-fluorobenzene (7.83 g, manufactured by TCI), cesium carbonate (19.5 g, manufactured by Kanto Chemical), and DMF (15 mL). The mixture was stirred at 130°C for 38 hours under an argon atmosphere. After completion of the reaction, the reaction solution was poured into a beaker containing saturated saline (250 mL). The mixture was filtered, and the residue was washed with water (50 mL) and methanol (10 mL). The crude product was purified using a silica gel column (toluene) to obtain the compound represented by the following formula (23) as a white powder (yield: 6.04 g, 92%).

[0208] 1H-NMR (400MHz, DMSO-d6): δ (ppm) = 7.34 (2H), 7.60 (2H), 7.69 (2H), 7.74 (2H), 8.60 (2H).

[0209] [ka]

[0210] A reaction vessel was charged with the compound represented by formula (23) (5.0 g), 4,4'-dimethoxydiphenylamine (5.27 g, manufactured by TCI), palladium acetate (0.11 g, manufactured by Kanto Chemical), sodium t-butoxide (5.19 g, manufactured by Kanto Chemical), tri-t-butylphosphine (33% xylene solution) (0.67 g, manufactured by Kanto Chemical), and toluene (30 mL). The mixture was then degassed under reduced pressure under an argon atmosphere. The mixture was heated and refluxed for 4 hours. After completion of the reaction, the reaction solution was filtered through Celite. The residue was washed with toluene (30 mL), and the filtrate was concentrated. The crude product was purified using a silica gel column (toluene → toluene / acetone = 100 / 1 (volume ratio)) to obtain the compound represented by formula (24) below as a yellow powder (yield: 3.10 g, 39%).

[0211] A reaction vessel was charged with the compound represented by the following formula (24) (3.10 g), bispinacolatodiboron (2.13 g, manufactured by TCI), potassium acetate (2.06 g, manufactured by Kanto Chemical), 1,1'-bis(diphenylphosphino)ferrocenedichloropalladium (0.343 g, manufactured by Kanto Chemical), and 1,4-dioxane (27 mL), and the mixture was degassed under reduced pressure under an argon atmosphere. The mixture was heated under reflux for 37 hours, and after the reaction was completed, the mixture was cooled to below 40°C and filtered through Celite. The filtrate was concentrated, and the crude product was purified using a silica gel column (toluene / acetone = 200 / 1 (volume ratio)). It was then purified again using a silica gel column (toluene) to obtain the compound represented by the following formula (25) as a yellow powder (yield: 2.56 g, 74%).

[0212] 1H-NMR (400MHz, DMSO-d6): δ (ppm) = 1.33 (12H), 3.69 (12H) 6.80-6.89 (16H), 7.07 (2H), 7.35 (2H), 7.63 (2H), 7.71 (2H), 7.93 (2H).

[0213] [ka]

[0214] A reaction vessel was charged with the compound of formula (18) (0.43 g), the compound of formula (25) (2.56 g), tetrakis(triphenylphosphine)palladium(0) (0.058 g, manufactured by Kanto Chemical Co., Inc.), potassium carbonate (0.44 g, manufactured by Kanto Chemical Co., Inc.), toluene (7 mL), ethanol (2 mL), and water (2 mL), and the mixture was degassed under reduced pressure. The mixture was heated under reflux for 7 hours under an argon atmosphere. After the reaction was completed, toluene (20 mL) and water (10 mL) were added. The mixture was separated, and the aqueous layer was extracted twice with toluene (20 mL). The organic layer was concentrated. The crude product was purified using a silica gel column (toluene / acetone = 100 / 1 (volume ratio)) to obtain the compound represented by formula (A-10) below as a dark blue powder (yield: 1.65 g, 84%).

[0215] 1 H-NMR (400MHz, THF-d8): δ (ppm) = 3.68 (24H) 6.72 (16H), 6.91 (16H), 7.08 (4H), 7.31 (4H), 7.53 (2H), 7.63-7.66 (8H), 7.90 (4H).

[0216] [ka]

[0217] [Synthesis Example 4] Synthesis of Compound (A-12) A reaction vessel was charged with 0.43 g of the compound represented by formula (18), 2.04 g of the compound represented by formula (26), 0.058 g of tetrakis(triphenylphosphine)palladium(0) (Kanto Chemical), 0.44 g of potassium carbonate (Kanto Chemical), 7 mL of toluene, 2 mL of ethanol, and 2 mL of water. The mixture was degassed under reduced pressure. The mixture was heated under reflux for 7 hours under an argon atmosphere. After the reaction was completed, 20 mL of toluene and 10 mL of water were added. The mixture was separated, and the aqueous layer was extracted twice with 20 mL of toluene. The organic layer was concentrated. The crude product was purified using a silica gel column (toluene) and a silica gel column (toluene:hexane = 2 / 1 (volume ratio)) to obtain the compound represented by formula (A-12) as a dark purple powder (yield: 1.42 g, 86%).

[0218] 1 H-NMR (400MHz, THF-d8): δ(ppm)=6.84(8H), 7.00(16H), 7.13(16H), 7.19(4H), 7.39(4H), 7.55(2H), 7.68(4H), 7.86(4H), 7.93(4H).

[0219] [ka]

[0220] [Synthesis Example 5] Synthesis of Compound (A-13) A reaction vessel was charged with 0.43 g of the compound represented by formula (18), 2.52 g of the compound represented by formula (27), 0.058 g of tetrakis(triphenylphosphine)palladium(0) (Kanto Chemical), 0.44 g of potassium carbonate (Kanto Chemical), 7 mL of toluene, 2 mL of ethanol, and 2 mL of water. The mixture was degassed under reduced pressure. The mixture was heated under reflux for 7 hours under an argon atmosphere. After the reaction was completed, 20 mL of toluene and 10 mL of water were added. The mixture was separated, and the aqueous layer was extracted twice with 20 mL of toluene. The organic layer was concentrated. The crude product was purified using a silica gel column (toluene / ethyl acetate = 50 / 1 (volume ratio)) to obtain the compound represented by formula (A-13) as a black powder (yield: 1.52 g, 75%).

[0221] 1 H-NMR (400MHz, THF-d8): δ(ppm)=3.67(24H)6.65(16H), 6.84(16H), 6.96(4H), 7.11(4H), 7.35(2H), 7.55-7.58(8H), 7.80(4H).

[0222] [ka]

[0223] [Synthesis Example 6] Synthesis of Compound (A-14) A reaction vessel was charged with the compound of formula (10) (0.43 g), the compound of formula (28) (2.48 g), tetrakis(triphenylphosphine)palladium(0) (0.058 g, manufactured by Kanto Chemical Co., Inc.), potassium carbonate (0.44 g, manufactured by Kanto Chemical Co., Inc.), toluene (7 mL), ethanol (2 mL), and water (2 mL), and the mixture was degassed under reduced pressure. The mixture was heated under reflux for 7 hours under an argon atmosphere. After the reaction was completed, toluene (20 mL) and water (10 mL) were added. The mixture was separated, and the aqueous layer was extracted twice with toluene (20 mL). The organic layer was concentrated. The crude product was purified using a silica gel column (toluene / ethyl acetate = 50 / 1 (volume ratio)) to obtain the compound represented by formula (A-14) as a black powder (yield: 1.52 g, 77%).

[0224] 1 H-NMR (400MHz, THF-d8): δ (ppm) = 3.68 (24H) 6.68 (16H), 6.88 (16H), 7.00 (4H), 7.15 (4H), 7.39 (2H), 7.60-7.63 (8H), 7.85 (4H).

[0225] [ka]

[0226] [Synthesis Example 7] Synthesis of Compound (A-25) A reaction vessel was charged with the compound of formula (29) (0.32 g), [4-[bis(4-methoxyphenyl)amino]phenyl]boronic acid (0.49 g, manufactured by TCI), tetrakis(triphenylphosphine)palladium(0) (0.03 g, manufactured by Kanto Chemical), potassium carbonate (0.22 g, manufactured by Kanto Chemical), toluene (4 mL), ethanol (1.3 mL), and water (1.3 mL), and the mixture was degassed under reduced pressure. The mixture was stirred under reflux for 6 hours under an argon atmosphere. After the reaction was completed, the reaction solution was poured into water (100 mL). 20 mL of toluene was added to the mixture, followed by separation. The organic layer was dried over magnesium sulfate and concentrated. The crude product was purified using a silica gel column (toluene) to obtain the compound represented by formula (A-25) (0.40 g, yield: 69%) as a dark green powder.

[0227] 1 H-NMR (400MHz, THF-d8): δ (ppm) = 3.73 (12H), 6.81-6.88 (12H), 7.02 (8H), 7.13 (2H), 7.16 (4H), 7.38 (4H).

[0228] [ka]

[0229] [Synthesis Example 8] Synthesis of Compound (A-26) A reaction vessel was charged with the compound of formula (29) (0.32 g), the compound of formula (30) (1.15 g), tetrakis(triphenylphosphine)palladium(0) (0.03 g, manufactured by Kanto Chemical Co., Inc.), potassium carbonate (0.22 g, manufactured by Kanto Chemical Co., Inc.), toluene (4 mL), ethanol (1.3 mL), and water (1.3 mL), and the mixture was degassed under reduced pressure. The mixture was stirred under reflux for 6 hours under an argon atmosphere. After the reaction was completed, the reaction solution was poured into water (100 mL). Toluene (20 mL) was added and the mixture was separated. The organic layer was dried over magnesium sulfate and then concentrated. The crude product was purified using a silica gel column (toluene / ethyl acetate = 40 / 1 (volume ratio)) to obtain the compound represented by formula (A-26) as a dark green powder (yield: 0.64 g, 61%).

[0230] 1 H-NMR (400MHz, THF-d8): δ(ppm)=3.61(24H), 6.62-6.65(16H), 6.80-6.84( 16H), 7.00(4H), 7.17(2H), 7.23(6H), 7.38(2H), 7.53-7.58(8H), 7.80(4H).

[0231] [ka]

[0232] [Synthesis Example 9] Synthesis of Compound (B-1) The compound (A-1) (0.20 g), malononitrile (0.07 g, manufactured by TCI), and THF (30 mL) were placed in a reaction vessel. The mixture was stirred under an argon atmosphere. 1.6 mL of an acetic acid-pyridine (1:1 (volume ratio)) solution was added thereto. The mixture was stirred for 20 hours under reflux with heating. After the reaction was completed, the reaction solution was placed in a beaker containing 50 mL of water. The mixture was separated, and the organic layer was washed twice with 50 mL of water. The organic layer was dried over magnesium sulfate and then concentrated. The crude product was purified using a silica gel column (toluene) to obtain the compound represented by the following formula (B-1) as a dark purple powder (yield: 0.17 g, 81%).

[0233] [ka]

[0234] [Synthesis Example 10] Synthesis of Compound (B-13) The compound of formula (18) (0.88 g), 4-(diphenylamino)phenylboronic acid (1.73 g, Sigma-Aldrich), tetrakis(triphenylphosphine)palladium(0) (0.12 g, Kanto Chemical), potassium carbonate (0.90 g, Kanto Chemical), toluene (13 mL), ethanol (4.5 mL), and water (4.5 mL) were placed in a reaction vessel and degassed under reduced pressure. The mixture was heated under reflux for 13 hours under an argon atmosphere. After completion of the reaction, the reaction solution was poured into a beaker containing ethanol (50 mL). The mixture was filtered and washed twice with water (50 mL) and then with ethanol (20 mL). The crude product was purified using a silica gel column (toluene → chloroform). The crystals were then dispersed and washed with toluene to obtain the compound represented by formula (31) below as a dark blue powder (yield: 1.14 g, 67%).

[0235] 1H-NMR (400MHz, THF-d8): δ (ppm) = 7.01 (8H), 7.06 (8H), 7.23 (8H), 7.25 (2H), 7.47 (4H).

[0236] [ka]

[0237] The compound of formula (31) (0.60 g), malononitrile (0.23 g, manufactured by TCI), and THF (50 mL) were placed in a reaction vessel and stirred under an argon atmosphere. An acetic acid-pyridine (1:1) solution (5.6 mL) was then added. The mixture was stirred for 32 hours under reflux. After the reaction was completed, the reaction solution was placed in a beaker containing water (300 mL). The mixture was filtered and washed with water (20 mL) and methanol (20 mL). The crude product was dispersed and washed with acetone and recrystallized (chloroform), yielding the compound represented by formula (B-13) below as a black powder (yield: 0.44 g, 69%).

[0238] 1H-NMR (400MHz, THF-d8): δ (ppm) = 7.01 (8H), 7.06 (8H), 7.23 (8H), 7.45 (4H), 7.49 (2H).

[0239] [ka]

[0240] [Synthesis Example 11] Synthesis of Compound (B-14)

[0241] The compound of formula (A-8) (0.57 g), malononitrile (0.13 g, manufactured by TCI), and THF (15 mL) were placed in a reaction vessel and stirred under an argon atmosphere. An acetic acid-pyridine (volume ratio 1:1) solution (3.6 mL) was then added. The mixture was stirred for 6 hours under reflux. After the reaction was completed, water (30 mL) and toluene (20 mL) were added. The mixture was separated, and the aqueous layer was extracted twice with toluene (30 mL). The organic layer was dried over magnesium sulfate and then concentrated. The crude product was purified using a toluene column to obtain the compound represented by formula (B-14) below as a dark green powder (yield: 0.493 g, 83%).

[0242] 1 H-NMR (400MHz, DMSO-d6): δ(ppm)=3.72(12H), 3.73(6H), 6.7-6.8(8H), 6.89(8H), 6.92(8H), 7.00(8H), 7.05(4H), 7.23(2H), 7.33(4H).

[0243] [ka]

[0244] [Synthesis Example 12] Synthesis of Compound (B-15) The compound of formula (A-10) (0.56 g), malononitrile (0.09 g, manufactured by TCI), and THF (15 mL) were placed in a reaction vessel and stirred under an argon atmosphere. An acetic acid-pyridine (1:1) solution (2.6 mL) was then added. The mixture was stirred for 16 hours under reflux. After the reaction was completed, water (30 mL) was added. The mixture was filtered and washed with water (30 mL) and methanol (20 mL). The crude product was recrystallized (chloroform / acetone) to obtain the compound represented by formula (B-14) below as a green powder (yield: 0.52 g, 91%).

[0245] 1 H-NMR (400MHz, THF-d8): δ (ppm) = 3.68 (24H) 6.72 (16H), 6.91 (16H), 7.08 (4H), 7.3 (4H), 7.66 (8H), 7.76 (2H), 7.90 (4H).

[0246] [ka]

[0247] [Synthesis Example 13] Synthesis of Compound (B-16) The compound of formula (A-12) (0.60 g), malononitrile (0.12 g, manufactured by TCI), and THF (19 mL) were placed in a reaction vessel and stirred under an argon atmosphere. An acetic acid-pyridine (1:1) solution (3.2 mL) was then added. The mixture was stirred for 54 hours under reflux. After the reaction was completed, the reaction solution was poured into water (200 mL). The mixture was filtered and washed with water (30 mL) and methanol (20 mL). The crude product was washed with toluene and recrystallized (chloroform / acetone) to obtain the compound represented by formula (B-16) below as a green powder (yield: 0.30 g, 48%).

[0248] 1 H-NMR (400MHz, THF-d8): δ(ppm)=6.84(8H), 7.00(16H), 7.13(16H), 7.19(4H), 7.39(4H), 7.55(2H), 7.68(4H), 7.86(4H), 7.93(4H).

[0249] [ka]

[0250] [Synthesis Example 14] Synthesis of Compound (B-17) The compound of formula (A-13) (0.56 g), malononitrile (0.09 g, manufactured by TCI), and THF (15 mL) were placed in a reaction vessel and stirred under an argon atmosphere. An acetic acid-pyridine (1:1) solution (2.6 mL) was then added. The mixture was stirred for 16 hours under reflux. After the reaction was completed, water (30 mL) was added. The mixture was filtered and washed with water (30 mL) and methanol (20 mL). The crude product was recrystallized (chloroform / acetone) to obtain the compound represented by formula (B-17) below as a green powder (yield: 0.51 g, 88%).

[0251] 1 H-NMR (400MHz, THF-d8): δ (ppm) = 3.67 (24H) 6.65 (16H), 6.84 (16H), 6.96 (4H), 7.11 (4H), 7.57 (8H), 7.59 (2H), 7.80 (4H).

[0252] [ka]

[0253] [Synthesis Example 15] Synthesis of Compound (B-18) The compound of formula (A-13) (0.55 g), malononitrile (0.09 g, manufactured by TCI), and THF (15 mL) were placed in a reaction vessel and stirred under an argon atmosphere. An acetic acid-pyridine (1:1) solution (2.6 mL) was then added. The mixture was stirred for 16 hours under reflux. After the reaction was completed, water (30 mL) was added. The mixture was filtered and washed with water (30 mL) and methanol (20 mL). The crude product was recrystallized (chloroform / acetone) to obtain the compound represented by formula (B-18) below as a green powder (yield: 0.51 g, 90%).

[0254] 1H-NMR (400MHz, THF-d8): δ (ppm) = 3.68 (24H) 6.68 (16H), 6.88 (16H), 7.00 (4H), 7.15 (4H), 7.62 (8H), 7.64 (2H), 7.85 (4H).

[0255] [ka]

[0256] [Synthesis Example 16] Synthesis of Compound (B-19) A reaction vessel was charged with the compound of formula (32) (1.33 g), [4-[bis(4-methoxyphenyl)amino]phenyl]boronic acid (2.10 g, manufactured by TCI), tetrakis(triphenylphosphine)palladium(0) (0.12 g, manufactured by Kanto Chemical), potassium carbonate (0.90 g, manufactured by Kanto Chemical), toluene (13 mL), ethanol (4.5 mL), and water (4.5 mL), and the mixture was degassed under reduced pressure. The mixture was heated under reflux for 6 hours under an argon atmosphere. After the reaction was completed, toluene (10 mL) and water (10 mL) were added. The mixture was separated, and the aqueous layer was extracted twice with toluene (20 mL). The organic layer was concentrated, and the crude product was purified using a silica gel column (toluene) to obtain the compound represented by formula (B-19) as a dark green powder (yield: 2.11 g, 86%).

[0257] 1 H-NMR (400MHz, CDCl3): δ(ppm)=1.32(6H), 3.81(12H), 4.59(4H), 6.84(8H), 6.90(4H), 7.08(8H), 7.33(4H)7.69(2H).

[0258] [ka]

[0259] [Synthesis Example 17] Synthesis of Compound (B-20) The compound of formula (A-1) (0.6 g), diethyl malonate (0.37 g, manufactured by TCI), and THF (14 mL) were added to a reaction vessel and stirred under an argon atmosphere. The mixture was cooled to below 5°C in an ice bath, and carbon tetrachloride (0.9 mL, manufactured by Junsei Chemical Co., Ltd.), titanium tetrachloride (0.5 mL, manufactured by Wako Pure Chemical Industries, Ltd.), and THF (8 mL) were added. The mixture was cooled again to below 5°C, and pyridine (1 mL) and THF (1 mL) were added. The mixture was then warmed to room temperature and stirred at room temperature for 17 hours. After completion of the reaction, the reaction solution was poured into a beaker containing 50 mL of water, and toluene (30 mL) was added. The mixture was separated, and the organic layer was washed twice with 10% aqueous sodium carbonate solution (50 mL). The organic layer was dried over magnesium sulfate and concentrated. The crude was purified using a silica gel column (toluene) to obtain a compound represented by the following formula (B-20) as a dark green powder (amount: 0.56 g, yield: 79%).

[0260] 1 H-NMR (400MHz, CDCl3): δ(ppm)=1.38(6H), 3.81(12H), 4.40(4H), 6.84(8H), 6.90(4H), 7.07(8H), 7.31(4H), 7.36(2H).

[0261] [ka]

[0262] [Synthesis Example 18] Synthesis of Compound (B-21) The compound of formula (A-1) (0.6 g), methyl cyanoacetate (0.23 g, manufactured by TCI), and THF (14 mL) were added to a reaction vessel and stirred under an argon atmosphere. The mixture was cooled to below 5°C in an ice bath, and carbon tetrachloride (0.9 mL, manufactured by Junsei Chemical Co., Ltd.), titanium tetrachloride (0.5 mL, manufactured by Wako Pure Chemical Industries, Ltd.), and THF (8 mL) were added. The mixture was cooled again to below 5°C, and pyridine (1 mL) and THF (1 mL) were added. The mixture was then warmed to room temperature and stirred at room temperature for 18 hours and at 60°C for 14 hours. After completion of the reaction, the reaction solution was poured into a beaker containing 50 mL of water, and toluene (30 mL) was added. The mixture was separated, and the organic layer was washed twice with 10% aqueous sodium carbonate solution (50 mL). The organic layer was dried over magnesium sulfate and concentrated. The crude was purified using a silica gel column (toluene) to obtain a compound represented by the following formula (B-21) as a dark green powder (amount: 0.51 g, yield: 77%).

[0263] 1 H-NMR (400MHz, CDCl3): δ(ppm)=3.81(12H), 3.95(3H), 6.84(8H), 6.90(4H), 7.07(8H), 7.34(4H), 7.68(1H), 7.82(1H).

[0264] [ka]

[0265] [Synthesis Example 19] Synthesis of Compound (B-22) The above formula (A-25) (0.35 g), diethyl malonate (0.27 mL, manufactured by TCI), and THF (11 mL) were placed in a reaction vessel and stirred under an argon atmosphere. Pyridine (0.48 mL, manufactured by Nacalai Tesque) was then added. Titanium tetrachloride (0.24 mL, manufactured by Wako Pure Chemical Industries, Ltd.) was then added. The mixture was stirred at room temperature for 9 hours. After the reaction was completed, the reaction solution was poured into a beaker containing water (150 mL). This was filtered, washed with water (30 mL) and methanol (20 mL), and dried. The crude product was purified using a silica gel column (toluene / ethyl acetate = 50 / 1 (volume ratio)) to obtain the compound represented by the following formula (B-22) as a dark green powder (yield: 0.32 g, 82%).

[0266] 1 H-NMR (400MHz, THF-d8): δ(ppm)=1.35(6H), 3.73(12H), 4.39(4H), 6.81-6.88(12H), 7.02(8H), 7.12(2H), 7.15(2H), 7.39-7.42(6H).

[0267] [ka]

[0268] [Synthesis Example 20] Synthesis of Compound (B-23) The compound of formula (A-26) (0.32 g), malononitrile (0.05 g, manufactured by TCI), and THF (8 mL) were placed in a reaction vessel and stirred under an argon atmosphere. A mixture of acetic acid and pyridine (volume ratio = 1:1) (1.4 mL) was added, and the mixture was heated under reflux for 20 hours. After the reaction was completed, the reaction solution was poured into a beaker containing 150 mL of water. The mixture was filtered, washed with water (20 mL) and methanol (20 mL), and then dried. The crude product was purified using a silica gel column (toluene / ethyl acetate = 40 / 1 (volume ratio)) to obtain the compound represented by formula (B-23) below as a dark green powder (yield: 0.26 g, 81%).

[0269] 1H-NMR (400MHz, THF-d8): δ(ppm)=3.67(24H), 6.69-6.71(16H), 6.88-6.90( 16H), 7.07(4H), 7.28-7.31(6H), 7.47(4H), 7.61(4H), 7.64(4H), 7.89(4H).

[0270] [ka]

[0271] [Example 1] <Formation of Electron Transport Layer> A coating liquid for the electron transport layer was prepared by adding ultrapure water to an aqueous colloidal dispersion of tin oxide (manufactured by Alfa Aesar, 1.75 wt %) to dilute it to 1 / 10.

[0272] An ITO substrate was used as a conductive support and ultrasonically cleaned in an aqueous solution containing a 2% volumetric concentration of alkaline detergent. The substrate was then rinsed with water and then ultrasonically cleaned in ethanol. The ITO substrate was then subjected to a 10-minute UV ozone treatment. The electron transport layer coating solution was then dropped onto the ITO substrate and spin-coated at 5,000 rpm for 30 seconds using a spin coater. The resulting thin film was then heated on a hot plate at 150°C for 40 minutes.

[0273] In the fabricated photoelectric conversion element, the electron transport layer made of tin oxide formed on the ITO substrate was a porous SnO2 film with a thickness of approximately 20 nm. Furthermore, when the crystallinity of the electron transport layer was examined using X-ray diffraction, it was found that a thin film of non-crystalline (amorphous) tin oxide (SnOx) without a crystalline structure was partially formed on the surface of the SnO2.

[0274] <Photoelectric conversion layer (perovskite layer) deposition> Lead iodide (1.2 M, PbI2), formate iodide (1 M, FAI), methylammonium bromide (0.2 M, MABr), and cesium iodide (0.06 M, CsI) were weighed into a vial and dissolved in a 4:1 (volume ratio) mixture of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). This solution was stirred at room temperature for 1 hour to prepare a 1.0 mol / L perovskite precursor solution. After stirring for an additional 30 minutes, the perovskite precursor solution was filtered through a PTFE filter with a 0.45 μm pore size to obtain the coating solution for the photoelectric conversion layer.

[0275] In an atmosphere with a relative humidity of 20%, the coating solution for the photoelectric conversion layer was dropped onto the ITO substrate on which the electron transport layer had been formed, and then coated by spin coating at 1000 rpm for 10 seconds and 3000 rpm for 30 seconds. The thin film was then stored in the atmosphere for 10 minutes, and then heated on a hot plate at 180°C for 10 minutes to obtain the FA. 0.83 MA 0.17 Pb(I 0.9 Br 0.05 A photoelectric conversion layer (perovskite layer) was formed consisting of mixed cations (FA, MA) and mixed halogens (I, Br) shown in the composition (3). FA stands for formamide, and MA stands for methylammonium. The thickness of the photoelectric conversion layer was measured using a scanning electron microscope (SEM) and found to be approximately 450-600 nm.

[0276] <Formation of the intermediate layer> 4 mg of 2-phenylethylammonium bromide (PEABr) was dissolved in 1 mL of 2-propanol and stirred at 50°C for 2 hours. The PEABr solution was spin-coated onto the photoelectric conversion layer (perovskite layer) at 5000 rpm for 30 seconds. The coated film was left in a reduced pressure atmosphere of 0.05 kPa for 10 minutes to remove the solvent.

[0277] <Formation of Hole Transport Layer> 16 mg of compound (A-10) was weighed into a vial, 0.5 mL of dehydrated chlorobenzene was added, and the mixture was dissolved by ultrasonication for 60 minutes. 9.1 μL of lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI, 340 mg / 1 mL acetonitrile solution) and 9.8 μL of 4-tert-butylpyridine (tBP) were added, and the mixture was filtered through a PTFE filter with a pore size of 0.45 μm to prepare a coating solution for the hole transport layer.

[0278] The hole transport layer coating solution was applied onto the intermediate layer (PEABr film) by spin coating at 3000 rpm for 30 seconds to form a hole transport layer, which was then dried by heating on a hot plate at 110°C for 1 hour. The thickness of the hole transport layer was measured using a scanning electron microscope (SEM) and found to be approximately 100 nm.

[0279] Gold was deposited on the hole transport layer of the fabricated element using a resistance heating vacuum deposition method to form a metal counter electrode approximately 100 nm thick. After that, UV-curable epoxy resin was applied around the periphery of the element using a dispenser, and the element was sealed with resin by irradiating it with UV light.

[0280] <Evaluation of photoelectric conversion elements> The obtained photoelectric conversion element was subjected to an air mass (AM) of 1.5G and an irradiance of 100mW / cm 2 The current-voltage characteristics between the negative electrode (ITO) and the positive electrode were measured using simulated sunlight from a solar simulator. A source meter (Keithley, Model 2400) was used for the measurements, and the short-circuit photocurrent (Jsc), open-circuit voltage (Voc), fill factor (FF), and photoelectric conversion efficiency (PCE) (%) were calculated from the measurement results. Table 1 shows these values, which were calculated based on the measurement results immediately after the photoelectric conversion element was fabricated.

[0281] [Example 2] Except for not using the intermediate layer, a photoelectric conversion element was produced in the same manner as in Example 1. Table 1 shows values ​​calculated based on the measurement results immediately after the production of the photoelectric conversion element.

[0282] [Example 3] 16 mg of compound (A-1) was weighed into a vial, 1 mL of dehydrated chlorobenzene was added, and the solution was dissolved by ultrasonication for 60 minutes. 9.1 μL of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, 340 mg / 1 mL acetonitrile solution) and 9.8 μL of 4-tert-butylpyridine (tBP) were added, and the solution was filtered through a PTFE filter with a pore size of 0.45 μm to prepare a compound (A-1) solution. 17 mg of compound (B-1) was weighed into a vial, 0.5 mL of dehydrated chlorobenzene was added, and the solution was dissolved by ultrasonication for 60 minutes. Similarly to compound (A-1), Li-TFSI solution and tBP were added, and the solution was filtered through a PTFE filter to obtain a compound (B-1) solution. The compound (A-1) solution and the compound (B-1) solution were mixed at a volume ratio of 1:3 to obtain a mixed hole transport layer coating solution. In this case, the molar ratio of compound (A-1) to compound (B-1) was 1:6. A photoelectric conversion element was produced in the same manner as in Example 1, except for using this mixed hole transport layer coating liquid. Table 1 shows the values ​​calculated based on the measurement results immediately after producing the photoelectric conversion element.

[0283] [Example 4] A mixed hole transport layer coating solution was prepared in the same manner as in Example 2, except that the mixing ratio of compound (A-1) and compound (B-1) was adjusted to a molar ratio of 1:8, and a photoelectric conversion element was produced in the same manner as in Example 1, except that this mixed hole transport layer coating solution was used. Values ​​calculated based on measurement results immediately after production of the photoelectric conversion element are shown in Table 1. Table 2 also shows the results of tracking the change in photoelectric conversion efficiency over time, with the time immediately after production of the element set as 0 hours and 6 hours and 24 hours later.

[0284] [Example 5] A mixed hole transport layer coating solution was prepared in the same manner as in Example 2, except that the mixing ratio of compound (A-1) and compound (B-1) was adjusted to a molar ratio of 1:10, and a photoelectric conversion element was produced in the same manner as in Example 1, except that this mixed hole transport layer coating solution was used. Table 1 shows values ​​calculated based on the measurement results immediately after producing the photoelectric conversion element.

[0285] [Comparative Example 1] A photoelectric conversion element was prepared in the same manner as in Example 1, except that Spiro-OMeTAD (36.15 mg), a commercially available hole-transporting compound represented by the following formula (C-1) that is most widely used in perovskite solar cells, was used as the hole-transporting material. Table 1 shows the values ​​calculated based on the measurement results 24 hours after preparation. Table 2 also shows the results of tracking the change in photoelectric conversion efficiency over time, with the time immediately after preparation of the element set as 0 hours and 6 and 24 hours later.

[0286] [ka]

[0287] [Table 1]

[0288] The results in Table 1 show that the device using the hole transport material for photoelectric conversion device of the present invention provides higher conversion efficiency than the device using commercially available hole transport material for photoelectric conversion device. It can be seen that the compound represented by general formula (1) exhibits sufficient photoelectric conversion efficiency even when used alone, and furthermore, by mixing it with the compound represented by general formula (3), it exhibits higher photoelectric conversion efficiency than the comparative example while maintaining the advantage of the compound of general formula (1), which tends to have a high open circuit voltage.

[0289] [Table 2]

[0290] The results in Table 2 show that elements using the hole transport material for photoelectric conversion elements of the present invention do not require a holding time (time until the device efficiency stabilizes) to stabilize the device efficiency, compared to elements using commercially available hole transport materials for photoelectric conversion elements, and achieve high efficiency immediately after device fabrication, making them advantageous for industrial production. It is said that the commercially available hole transport material for photoelectric conversion elements used in the comparative example requires time for the device efficiency to stabilize. This is presumably because commercially available materials are relatively resistant to oxidation to oxidants that function as hole transport materials for photoelectric conversion elements. Because the compound of the present invention is easily oxidized to an oxidant, it is believed that the device efficiency stabilizes immediately after device fabrication.

[0291] [Example 6] Lead (II) iodide and cesium bromide were weighed into a vial in a molar ratio of 1:1, and DMF and DMSO were added as solvents in a volume ratio of 6:4. The mixture was stirred at room temperature for 1 hour to form a 1.0 mol / L perovskite precursor solution whose entire composition was composed of inorganic elements. A coating solution for a photoelectric conversion layer was prepared using this solution, and a photoelectric conversion layer (perovskite layer) composed of CsPbIBr was formed. In the same manner as in Example 1, except for this, compound (A-1) and compound (B-1) were mixed (volume ratio 1:4, molar ratio 1:8) and the resulting solutions were mixed to prepare a coating solution for a hole transport layer. A photoelectric conversion element was fabricated using this hole transport layer, and measurements were performed. The results are shown in Table 3.

[0292] Comparative Example 2 A photoelectric conversion element was prepared in the same manner as in Example 6 except that Spiro-OMeTAD was used as the hole transport material, and measurements were carried out. The results are shown in Table 3.

[0293] [Table 3]

[0294] The results in Table 2 show that the element using the hole transport material for photoelectric conversion elements of the present invention is superior to the element using a commercially available hole transport material for photoelectric conversion elements in that it has a higher open circuit voltage and provides sufficient photoelectric conversion efficiency. [Industrial Applicability]

[0295] Use of the hole transport material for photoelectric conversion elements according to the present invention is useful for high-efficiency photoelectric conversion elements and perovskite solar cells, and can provide clean energy as solar cells that can efficiently convert solar energy into electrical energy. [Explanation of symbols]

[0296] 1 Conductive support (electrode) 2 Electron transport layer 3 Photoelectric conversion layer 4. Middle class 5. Hole transport layer 6. Opposite

Claims

1. A compound represented by the following general formula (1), wherein X in the general formula (1) １ and X ２ are each independently represented by the following general formula (2): 【Chemical 1】 wherein R 3 , R 8 , R 13 and R 18 each independently represent a diphenylamino group which may have a substituent; The "substituent" of the optionally substituted diphenylamino group is a linear or branched alkoxy group having 1 to 18 carbon atoms, R 1 , R 2 , R 4 , R 5 , R 6 , R 7 , R 9 , R 10 , R 11 , R 12 , R 14 , R 15 , R 16 , R 17 , R 19 and R 20 represent a hydrogen atom. 。 R ５ and R ６ and R １５ and R １６ may be bonded to each other to form a ring. 【Chemistry 2】 [In the formula, R ２１ ~R ２６ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent; a linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent; a linear or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent; a cycloalkyl group having 3 to 10 carbon atoms which may have a substituent; a linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent; a cycloalkoxy group having 3 to 10 carbon atoms which may have a substituent; a thio group having 1 to 18 carbon atoms which may have a substituent; an amino group having 1 to 20 carbon atoms which may have a substituent; an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent; or an optionally substituted heterocyclic group having 5 to 36 ring atoms, R ２１ and R ２２ , R ２３ and R ２４ and R ２５ and R ２６ may be bonded to each other to form a ring. Y １ represents an oxygen atom, a sulfur atom, or a selenium atom, and m and n each represent an integer of 0 to 2, provided that m is 1 and n is 0.

2. A hole transport material for a photoelectric conversion device, comprising the compound according to claim 1.

3. A hole transport material for a photoelectric conversion element, characterized in that it is a compound represented by the following general formula (1), wherein X 1 and X 2 in general formula (1) each independently contain a compound represented by the following general formula (2), and contain a compound represented by the following general formula (3). 【Chemical 1】 [In general formula (1), R １ ~R ２０ are each independently a hydrogen atom, a halogen atom, a carboxyl group, a trimethylsilyl group, a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent; a linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent; a linear or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent; a cycloalkyl group having 3 to 10 carbon atoms which may have a substituent; a linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent; a cycloalkoxy group having 3 to 10 carbon atoms which may have a substituent; an acyl group having 1 to 20 carbon atoms which may have a substituent; a thio group having 1 to 18 carbon atoms which may have a substituent; an amino group having 1 to 20 carbon atoms which may have a substituent; an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent; or a heterocyclic group having 5 to 36 ring atoms which may have a substituent, R １ ~R ２０ is at least one halogen atom, carboxyl group, trimethylsilyl group, a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent; a linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent; a linear or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent; a cycloalkyl group having 3 to 10 carbon atoms which may have a substituent; a linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent; a cycloalkoxy group having 3 to 10 carbon atoms which may have a substituent; or an acyl group having 1 to 20 carbon atoms which may have a substituent; It shall have the following. R １ ~R ５ , R ６ ~R １０ , R １１ ~R １５ , R １６ ~R ２０ adjacent groups may be bonded to each other to form a ring, and R ５ and R ６ and R １５ and R １６ may be bonded to each other to form a ring. 【Chemistry 2】 [In general formula (2), R ２１ ~R ２６ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent; a linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent; a linear or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent; a cycloalkyl group having 3 to 10 carbon atoms which may have a substituent; a linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent; a cycloalkoxy group having 3 to 10 carbon atoms which may have a substituent; a thio group having 1 to 18 carbon atoms which may have a substituent; an amino group having 1 to 20 carbon atoms which may have a substituent; an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent; or an optionally substituted heterocyclic group having 5 to 36 ring atoms, R ２１ and R ２２ , R ２３ and R ２４ and R ２５ and R ２６ may be bonded to each other to form a ring. Y １ represents an oxygen atom, a sulfur atom, or a selenium atom, and m and n each represent an integer of 0 to 2, provided that either m or n is 1 or 2. 【Chemistry 3】 [In general formula (3), R ２７ and R ２８ are each independently nitrile groups, a linear or branched perfluoroalkyl group having 1 to 4 carbon atoms; a linear or branched acyl group having 1 to 18 carbon atoms which may have a substituent; a linear or branched alkoxycarbonyl group having 1 to 18 carbon atoms which may have a substituent; a thio group having 1 to 18 carbon atoms which may have a substituent; an amino group having 1 to 20 carbon atoms which may have a substituent; or a linear or branched alkylsulfonyl group having 1 to 18 carbon atoms which may have a substituent, R ２７ and R ２８ may be bonded to each other to form a ring. X １ and X ２ are each independently represented by the general formula (2), R ２９ ~R ３２ are each independently an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent; or a heterocyclic group having 5 to 36 ring atoms which may have a substituent. R ２９ and R ３０ , R ３１ and R ３２ may be bonded to each other to form a ring.

4. 4. The hole transport material for a photoelectric conversion element according to claim 3, wherein the compound represented by the general formula (3) is represented by the following general formulas (4) to (6): 【Chemistry 4】 [In the formula, R ２７ and R ２８ are each independently the same as defined above, and R ２７ and R ２８ may be bonded to each other to form a ring. X １ and X ２ are each independently represented by the general formula (2), R ３３ ~R ５２ are each independently a hydrogen atom, a halogen atom, a trimethylsilyl group, a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent; a linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent; a linear or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent; a cycloalkyl group having 3 to 10 carbon atoms which may have a substituent; a linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent; a cycloalkoxy group having 3 to 10 carbon atoms which may have a substituent; an acyl group having 1 to 20 carbon atoms which may have a substituent; a thio group having 1 to 18 carbon atoms which may have a substituent; an amino group having 1 to 20 carbon atoms which may have a substituent; an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent; or an optionally substituted heterocyclic group having 5 to 36 ring atoms, R ３３ ~R ３７ , R ３８ ~R ４２ , R ４３ ~R ４７ , R ４８ ~R ５２ Adjacent groups may be bonded to each other to form a ring. 【Chemistry 5】 [In the formula, R ２７ and R ２８ are each independently the same as defined above, and R ２７ and R ２８ may be bonded to each other to form a ring. X １ and X ２ are each independently represented by the general formula (2), R ３３ ~R ５２ each independently represents the same group as above, R ３３ ~R ３６ , R ３９ ~R ４２ , R ４３ ~R ４６ , R ４９ ~R ５２ Adjacent groups may be bonded to each other to form a ring. 【Chemistry 6】 [In the formula, R ２７ and R ２８ are each independently the same as defined above, and R ２７ and R ２８ may be bonded to each other to form a ring. X １ and X ２ are each independently represented by the general formula (2), R ３３ ~R ５２ each independently represents the same group as above, R ３３ ~R ３６ , R ３９ ~R ４２ , R ４３ ~R ４６ , R ４９ ~R ５２ Adjacent groups may be bonded to each other to form a ring. Z １ and Z ２ each independently represents an oxygen atom, a sulfur atom, or a selenium atom.

5. 5. The hole transport material for a photoelectric conversion element according to claim 3, wherein the content of the compound represented by the general formula (3) is 3 to 96% by mass.

6. 6. The hole transport material for a photoelectric conversion element according to claim 3, wherein the content of the compound represented by general formula (3) is 50 to 94 mass %.

7. A photoelectric conversion element using the hole transport material for photoelectric conversion elements according to any one of claims 2 to 6.

8. A solar cell using the photoelectric conversion element according to claim 7.

Images