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

Abstract

The problem to be solved by the present invention is to provide a compound useful as a hole transport material for a photoelectric conversion element capable of efficiently obtaining current, a photoelectric conversion element and a solar cell having good photoelectric conversion characteristics using the compound in a hole transport layer. The present invention is a compound represented by the following general formula (1). In the formula, R 1 ~R 20 represents a hydrogen atom or an alkoxy group having 1 to 20 carbon atoms, and Y represents an oxygen atom or CR 21 R 22 , R 21 and R 22 It represents a nitrile group or an acyl group having 1 to 10 carbon atoms. #imgabs0#

Description

Technical Field

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

[0002] In recent years, solar power generation has attracted attention as a clean energy source, and the development of solar cells has been booming. Among these, the development of solar cells using perovskite materials for their photoelectric conversion layers (hereinafter referred to as perovskite solar cells) has attracted significant attention as low-cost, next-generation solar cells that can be manufactured using solution processes (e.g., Patent Document 1 and Non-Patent Documents 1 and 2).

[0003] For perovskite solar cells, hole transport materials are mostly used in the elements. The purposes of use include: (1) improving the function of selectively transporting holes and improving the photoelectric conversion efficiency; (2) bonding with the perovskite photoelectric conversion layer to protect the perovskite material that is easily affected by moisture and oxygen (for example, non-patent document 3). As a standard hole transport material, Spiro-OMeTAD, a spirobifluorene-based organic compound, is mostly used, but there are few reports on hole transport materials that are more helpful for photoelectric conversion characteristics than this material.

[0004] Patent Document 1: US10937972 B2

[0005] Non-patent document 1: Journal of the American Chemical Society, 2009, Vol. 131, P. 6050-6051

[0006] Non-patent document 2: Science, 2012, Vol. 388, P. 643-647

[0007] Non-patent literature 3: Chem. Sci., 2019, 10, pp. 6748-6769 Summary of the Invention

[0008] The problem to be solved by the present invention is to provide a compound useful as a hole transport material for a photoelectric conversion element capable of efficiently extracting current, and a photoelectric conversion element and a solar cell having excellent photoelectric conversion characteristics using the compound in a hole transport layer.

[0009] To address the above-mentioned issues, the inventors conducted intensive research to improve photoelectric conversion properties. As a result, they discovered that by designing and developing a compound with a specific structure and using it as a hole-transport layer in a photoelectric conversion element, they could produce a photoelectric conversion element and a perovskite solar cell exhibiting high photoelectric conversion efficiency. The present invention primarily encompasses the following aspects.

[0010] 1. A compound represented by the following general formula (1).

[0011] [Chemical Formula 1]

[0012]

[0013] Where R 1 ~R 20 each independently represents 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 cycloalkyl group having 3 to 10 carbon atoms which may have a substituent, an 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 thiol 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,

[0014] R 1 and R 2 、R 2 and R 3 、R 3 and R 4 、R 4 and R 5 、R 6 and R 7 、R 7 and R 8 、R 8 and R 9 、R 9 and R 10 、R 11 and R 12 、R 12 and R 13 、R 13 and R 14 、R 14 and R 15 、R 16 and R 17 、R 17 and R 18 、R 18 and R 19 , and R 19 and R 20 can bond to each other to form a ring, R 5 and R 6 , and R 15 and R 16 They can bond to each other to form a ring.

[0015] X 1 and X 2 represents a divalent group,

[0016] Y represents an oxygen atom or CR 21 R 22 ,

[0017] R 21 and R 22 Each independently represents a nitrile group, an acyl group having 1 to 10 carbon atoms which may have a substituent, or an alkoxycarbonyl group having 1 to 10 carbon atoms which may have a substituent, and R 21 and R 22 They can bond to each other to form a ring.

[0018] 2. According to the compound, wherein, in the general formula (1), X 1 and X 2 It is represented by the following general formula (2).

[0019] [Chemical Formula 2]

[0020]

[0021] Where R 23 ~R 28 each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 10 carbon atoms which may have a substituent, a linear or branched alkenyl group having 2 to 10 carbon atoms which may have a substituent, a cycloalkyl group having 3 to 10 carbon atoms which may have a substituent, an aromatic hydrocarbon group having 6 to 18 carbon atoms which may have a substituent, or a heterocyclic group having 5 to 18 ring atoms which may have a substituent,

[0022] It can be, R 23 and R 24 、R 25 and R 26 and R 27 and R 28 can bond to each other to form a ring, Z represents an oxygen atom, a sulfur atom or a selenium atom,

[0023] m and n represent integers of 0 to 2, and both m and n are not 0 at the same time.

[0024] 3. The compound, wherein, in the general formula (2), m is 1.

[0025] 4. According to the compound, wherein, in the general formula (1), R 1 ~R 20Each of them is independently a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, a thiol group having 1 to 18 carbon atoms which may have a substituent, or an amino group having 1 to 20 carbon atoms which may have a substituent.

[0026] 5. A hole transport material formed from the compound.

[0027] 6. A photoelectric conversion element using the hole transport material.

[0028] According to the compound of the present invention and a hole transport layer using the compound, a photoelectric conversion element and a perovskite solar cell having good photoelectric conversion efficiency can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic cross-sectional views showing the structures of photoelectric conversion elements according to Examples and Comparative Examples. DETAILED DESCRIPTION

[0030] Hereinafter, embodiments of the present invention will be described in detail. The hole transport material of the present invention is suitable for use in photoelectric conversion devices and perovskite solar cells.

[0031] Photoelectric conversion element

[0032] like Figure 1 As shown in the schematic cross-sectional view of , the photoelectric conversion element of the present invention typically includes a conductive support 1 , an electron transport layer 2 , a photoelectric conversion layer 3 , a hole transport layer 4 , and a counter electrode 5 .

[0033] Hereinafter, the hole transport material used in the hole transport layer of the photoelectric conversion element of the present invention, that is, the compound represented by the above-mentioned general formula (1) will be specifically described, but the present invention is not limited thereto.

[0034] In the above general formula (1), R 1 ~R 20 Each independently represents 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 cycloalkyl group having 3 to 10 carbon atoms which may have a substituent, an 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 thiol 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.

[0035] As R 1 ~R 20 Examples of the "halogen atom" represented by include fluorine, chlorine, bromine and iodine.

[0036] As R 1 ~R 20 Examples of the “straight-chain or branched-chain alkyl group having 1 to 20 carbon atoms which may have a substituent” include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, n-hexyl, 2-ethylhexyl, heptyl, octyl, isooctyl, nonyl, and decyl.

[0037] As R 1 ~R 20 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” include vinyl group, 1-propenyl, 2-propenyl (allyl group), 1-methylvinyl, 1-butenyl, 2-butenyl, 1-pentenyl, 1-hexenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl, and 1-ethylvinyl; and straight-chain or branched alkenyl groups having 2 to 20 carbon atoms in which a plurality of these alkenyl groups are bonded.

[0038] As R 1 ~R 20 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" include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclodecyl, cyclododecyl, 4-methylcyclohexyl, and 4-ethylcyclohexyl.

[0039] As R 1 ~R 20 Examples of the “alkoxy group having 1 to 20 carbon atoms” in the “alkoxy group having 1 to 20 carbon atoms which may have a substituent” include methoxy, ethoxy, propoxy, n-butoxy, n-pentoxy, n-hexyloxy, heptoxy, octyloxy, nonyloxy, decyloxy, isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, isooctyloxy, tert-octyloxy, phenoxy, tolyloxy, biphenyloxy, terphenyloxy, naphthyloxy, anthryloxy, phenanthrenyloxy, fluorenyloxy, and indenyloxy.

[0040] As R 1 ~R 20Examples of the "linear or branched cycloalkoxy group having 3 to 10 carbon atoms" in the "cycloalkoxy group having 3 to 10 carbon atoms which may have a substituent" include cyclopropyloxy, cyclobutyloxy, cyclopentyloxy, cyclohexyloxy, and 4-methylcyclohexyloxy.

[0041] As R 1 ~R 20 The "acyl group having 1 to 20 carbon atoms" in the "acyl group having 1 to 20 carbon atoms which may have a substituent" includes acetyl, propionyl, butyryl, isobutyryl, valeryl, isovaleryl, benzoylacetyl, and benzoyl. The hydrogen atoms of the alkyl group in the acyl group may be partially substituted with fluorine atoms or completely substituted with fluorine atoms (perfluorinated). Furthermore, the acyl group may be bonded to an amino group (-CO-N<).

[0042] As R 1 ~R 20 Examples of the “sulfur group having 1 to 18 carbon atoms” in the “sulfur group having 1 to 18 carbon atoms which may have a substituent” include methylsulfur group, ethylsulfur group, propylsulfur group, phenylsulfur group and biphenylsulfur group.

[0043] As R 1 ~R 20 The “amino group having 1 to 20 carbon atoms” in the “amino group having 1 to 20 carbon atoms which may have a substituent” includes, for monosubstituted amino groups, ethylamino, acetylamino, and phenylamino, and, for disubstituted amino groups, diethylamino, diphenylamino, and acetylphenylamino.

[0044] As R 1 ~R 20 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" include phenyl, biphenyl, terphenyl, naphthyl, biphenyl, anthryl, phenanthrenyl, fluorenyl, indenyl, pyrenyl, perylenyl, fluorenyl, and triphenylenyl. Furthermore, the aromatic hydrocarbon group in the present invention includes a "condensed polycyclic aromatic group."

[0045] As R 1 ~R 20Examples 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” include pyridyl, pyrimidinyl, triazinyl, thienyl, furanyl, pyrrolyl, imidazolyl, pyrazolyl, triazolyl, quinolyl, isoquinolyl, naphthyridinyl, acridinyl, phenanthrolinyl, benzofuranyl, benzothiophenyl, oxazolyl, indolyl, carbazolyl, benzoxazolyl, thiazolyl, benzothiazolyl, quinoxalinyl, benzimidazolyl, pyrazolyl, dibenzofuranyl, dibenzothiophenyl, and carbolyl.

[0046] As R 1 ~R 20The “substituent” in the “straight-chain or branched alkyl group having 1 to 18 carbon atoms which may have a substituent”, “straight-chain or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent”, “cycloalkyl group having 3 to 10 carbon atoms which may have a substituent”, “alkoxy group having 1 to 20 carbon atoms which may have a substituent”, “cycloalkoxy group having 3 to 10 carbon atoms which may have a substituent”, “acyl group having 1 to 20 carbon atoms which may have a substituent”, “thiol group having 1 to 18 carbon atoms which may have a substituent”, “amino group having 1 to 20 carbon atoms which may have a substituent”, “aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent”, or “heterocyclic group having 5 to 36 ring atoms which may have a substituent” as represented by the formula (a) includes halogen atoms such as fluorine, chlorine, bromine and iodine atoms; a cyano group; a hydroxyl group; a nitro group; a nitroso group; a carboxyl group; a phosphate group; a thioxo group; and a thioxo group. group)(>C=S); trimethylsilyl; carboxylic acid ester groups such as methyl group and ethyl group; linear or branched alkyl groups having 1 to 18 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, n-hexyl, 2-ethylhexyl, heptyl, octyl, isooctyl, nonyl and decyl; vinyl group, 1-propenyl, 2-propenyl (allyl group), straight-chain or branched alkenyl groups having 2 to 18 carbon atoms, such as 1-butenyl, 2-butenyl, 1-pentenyl, 1-hexenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl and 1-ethylvinyl; alkoxy groups having 1 to 18 carbon atoms, such as methoxy, ethoxy, propoxy, tert-butoxy, pentyloxy and hexyl; aromatic hydrocarbon groups having 6 to 30 carbon atoms, such as phenyl, naphthyl, anthracenyl, phenanthrenyl and pyrenyl; pyridyl, pyrimidinyl, triazinyl, thienyl, furanyl, pyrrolyl, imidazolyl, pyrazolyl, triazolyl, quinolyl, isoquinolyl, naphthyridinyl, acridinyl, phenanthroline The term "substituent" includes heterocyclic groups having 5 to 30 ring atoms, such as benzofuranyl, benzothiophenyl, oxazolyl, indolyl, carbazolyl, benzoxazolyl, thiazolyl, benzothiazolyl, quinoxalinyl, benzimidazolyl, pyrazolyl, dibenzofuranyl, dibenzothiophenyl, and carbolinyl; amino groups having 0 to 18 carbon atoms, such as unsubstituted amino (-NH2), monosubstituted amino groups such as ethylamino, acetylamino, and phenylamino, and disubstituted amino groups such as diethylamino, diphenylamino, and acetylphenylamino; and sulfhydryl groups having 0 to 18 carbon atoms, such as unsubstituted sulfhydryl (thiol group: -SH), methylsulfhydryl, ethylsulfhydryl, propylsulfhydryl, phenylsulfhydryl, and biphenylsulfhydryl. These "substituents" may include multiple groups, and when included, they may be the same or different. Furthermore, these "substituents" may further have the substituents exemplified above.

[0047] R in the present invention 1 ~R20 Each of them is preferably independently a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, a thiol group having 1 to 18 carbon atoms which may have a substituent, or an amino group having 1 to 20 carbon atoms which may have a substituent, and more preferably a hydrogen atom or an alkoxy group having 1 to 10 carbon atoms. In particular, in order to improve the photoelectric conversion efficiency when used as a hole transport material in a photoelectric conversion element, it is preferred that: 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 is a hydrogen atom, R 3 、R 8 、R 13 and R 18 It is an alkoxy group having 1 to 10 carbon atoms.

[0048] In the present invention, R 1 and R 2 、R 2 and R 3 、R 3 and R 4 、R 4 and R 5 、R 6 and R 7 、R 7 and R 8 、R 8 and R 9 、R 9 and R 10 、R 11 and R 12 、R 12 and R 13 、R 13 and R 14 、R 14 and R 15 、R 16 and R 17 、R 17 and R 18 、R 18 and R 19 , and R 19 and R20 They may be bonded to each other via a single bond, an oxygen atom, a sulfur atom, a selenium atom, or a nitrogen atom to form a ring, R 5 and R 6 , and R 15 and R 16 They may also be bonded to each other via a single bond, an oxygen atom, a sulfur atom, a selenium atom or a nitrogen atom to form a ring. 5 and R 6 , and R 15 and R 16 When forming a ring, the rings are preferably formed by bonding to each other via a single bond, an oxygen atom, or a sulfur atom, and more preferably formed by bonding to each other via a single bond.

[0049] In the present invention, it is preferred that: Y represents an oxygen atom or CR 21 R 22 , R 21 and R 22 Each independently represents a nitrile group, an acyl group having 1 to 10 carbon atoms which may have a substituent, or an alkoxycarbonyl group having 1 to 10 carbon atoms which may have a substituent, and is electron-withdrawing.

[0050] As R 21 and R 22 The "acyl group having 1 to 10 carbon atoms which may have a substituent" represented by the above R 1 ~R 20 The acyl group having 1 to 10 carbon atoms in the "acyl group having 1 to 20 carbon atoms which may have a substituent" represented by .

[0051] As R 21 and R 22 The "alkoxycarbonyl group having 1 to 10 carbon atoms" in the "alkoxycarbonyl group having 1 to 10 carbon atoms which may have a substituent" includes methoxycarbonyl and ethoxycarbonyl. The hydrogen atoms of the alkyl group in the alkoxycarbonyl group may be partially substituted with fluorine atoms or all substituted with fluorine atoms (perfluorinated).

[0052] R 21 and R 22 They may be bonded to each other via a single bond, an oxygen atom, a sulfur atom, a selenium atom, or a nitrogen atom to form a ring. In addition, when forming a ring, an acidic heterocycle such as a barbituric acid-based, thiobarbituric acid-based, or indandione-based heterocycle is preferred.

[0053] In the present invention, in order to improve the photoelectric conversion efficiency when used as a hole transport material in a photoelectric conversion element, X in the above general formula (1) 1 and X 2 Preferred is a divalent group represented by the above-mentioned general formula (2).

[0054] In the above general formula (2), R 23 ~R 28 Each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 10 carbon atoms which may have a substituent, a linear or branched alkenyl group having 2 to 10 carbon atoms which may have a substituent, a cycloalkyl group having 3 to 10 carbon atoms which may have a substituent, an aromatic hydrocarbon group having 6 to 18 carbon atoms which may have a substituent, or a heterocyclic group having 5 to 18 ring atoms which may have a substituent.

[0055] As R 23 ~R 28 The "linear or branched alkyl group having 1 to 10 carbon atoms which may have a substituent" represented by the above R 1 ~R 20 The "linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent" herein refers to an alkyl group having 1 to 10 carbon atoms.

[0056] As R 23 ~R 28 The "linear or branched alkenyl group having 2 to 10 carbon atoms which may have a substituent" represented by the above R 1 ~R 20 The "straight-chain or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent" herein refers to an alkenyl group having 2 to 10 carbon atoms.

[0057] As R 23 ~R 28 The "cycloalkyl group having 3 to 10 carbon atoms which may have a substituent" represented by 1 ~R 20 The "cycloalkyl group having 3 to 10 carbon atoms which may have a substituent" represented herein is the same as the cycloalkyl group.

[0058] As R 23 ~R 28 The "aromatic hydrocarbon group having 6 to 18 carbon atoms which may have a substituent" represented by the above R 1 ~R 20 The aromatic hydrocarbon group having 6 to 18 carbon atoms among the "aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent" represented by .

[0059] As R 23 ~R 28 The "heterocyclic group having 5 to 18 ring atoms which may have a substituent" represented by the above R 1 ~R 20The heterocyclic group having 5 to 18 ring atoms among the "heterocyclic group having 5 to 36 ring atoms which may have a substituent" represented by .

[0060] R 23 and R 24 、R 25 and R 26 , and R 27 and R 28 They may be bonded to each other via a single bond, an oxygen atom, a sulfur atom, a selenium atom, or a nitrogen atom to form a ring.

[0061] Z in the above general formula (2) represents an oxygen atom, a sulfur atom or a selenium atom.

[0062] In the present invention, Z is preferably a sulfur atom.

[0063] In the general formula (2), m and n represent integers of 0 to 2. When m is 0, n is 1 to 2, and when n is 0, m is 1 to 2. That is, there is no case where both m and n are 0. m is preferably 1, and n is preferably 0 or 1. Furthermore, the fluorenone moiety, which is the central skeleton of the general formula (1), and the group represented by the general formula (2) may be bonded to the phenyl portion or to the 5-membered heterocyclic group portion.

[0064] Specific examples of the compounds represented by the general formula (1) of the present invention are shown below, but the present invention is not limited thereto. In addition, the following exemplary compounds are described by omitting some hydrogen atoms, carbon atoms, etc. to represent one example of possible isomers, and all other isomers are also included. In addition, mixtures of two or more isomers may also be used.

[0065] [Chemical Formula 3]

[0066]

[0067] [Chemical Formula 4]

[0068]

[0069] [Chemical Formula 5]

[0070]

[0071] [Chemical Formula 6]

[0072]

[0073] [Chemical Formula 7]

[0074]

[0075] [Chemical Formula 8]

[0076]

[0077] [Chemical Formula 9]

[0078]

[0079] [Chemical Formula 10]

[0080]

[0081] [Chemical Formula 11]

[0082]

[0083] [Chemical Formula 12]

[0084]

[0085] [Chemical Formula 13]

[0086]

[0087] [Chemical Formula 14]

[0088]

[0089] [Chemical Formula 15]

[0090]

[0091] [Chemical Formula 16]

[0092]

[0093] [Chemical Formula 17]

[0094]

[0095] The compound represented by the above general formula (1) can be synthesized by a known method.

[0096] For example, the compound represented by the general formula (1) can be synthesized by subjecting 2,7-dibromofluorenone represented by the following formula (3) to a Suzuki-Miyaura coupling reaction with a boronic acid compound represented by the following general formula (4) or (5) or a boronic ester compound represented by the following general formula (6) or (7), and then subjecting the 2,7-dibromofluorenone to a Knoevenagel condensation reaction with a compound represented by the following general formula (8).

[0097] [Chemical Formula 18]

[0098]

[0099] [Chemical Formula 19]

[0100]

[0101] The symbols in the formula are the same as those in the above general formula (1).

[0102] [Chemical Formula 20]

[0103]

[0104] The symbols in the formula are the same as those in the above general formula (1).

[0105] [Chemical Formula 21]

[0106]

[0107] The symbols in the formula are the same as those in the above general formula (1).

[0108] Examples of methods for purifying the compound represented by the general formula (1) include purification by column chromatography, purification by adsorption using silica gel, activated carbon, activated clay, etc., recrystallization from a solvent, purification by crystallization, etc. Alternatively, it is effective to use a compound whose purity has been improved by combining these methods. In addition, identification of these compounds can be performed using nuclear magnetic resonance analysis (NMR).

[0109] Hereinafter, preferred embodiments of the photoelectric conversion element of the present invention will be described.

[0110] like Figure 1 As shown, the photoelectric conversion element of the present invention preferably includes a conductive support 1, an electron transport layer 2, a photoelectric conversion layer 3, a hole transport layer 4 and a counter electrode 5, but is not limited thereto. In addition, the photoelectric conversion element of the present invention can be suitable for use as a solar cell, more preferably a perovskite photoelectric conversion element, but is not limited thereto. In the present invention, the perovskite photoelectric conversion element preferably includes a conductive support (electrode) 1, an electron transport layer 2, a photoelectric conversion layer (perovskite layer) 3, a hole transport layer 4 and a counter electrode 5 in sequence. In addition, the perovskite photoelectric conversion element can also be composed of a conductive support, a hole transport layer, a photoelectric conversion layer (perovskite layer), an electron transport layer, and a counter electrode in sequence.

[0111] <Conductive Support>

[0112] In the photoelectric conversion element of the present invention, Figure 1The conductive support 1 shown needs to have light transmittance capable of projecting light participating in the photoelectric conversion. In addition, the conductive support is a component having the function of obtaining current from the photoelectric conversion layer, and is therefore preferably a conductive substrate. Specific examples of conductive materials include: tin-doped indium oxide (ITO), zinc-doped indium oxide (IZO), tungsten-doped indium oxide (IWO), zinc and aluminum oxide (AZO), fluorine-doped tin oxide (FTO), indium oxide (In2O3) and indium-tin composite oxide, etc. Conductive transparent oxide semiconductors, etc., but tin-doped indium oxide (ITO) or fluorine-doped tin oxide (FTO) are preferably used.

[0113] Electron transport layer

[0114] In the photoelectric conversion element of the present invention, Figure 1 The electron transport layer 2 shown is a layer located between the conductive support 1 and the photoelectric conversion layer (perovskite layer) 3. The electron transport layer 2 is preferably formed on the conductive support 1, but is not particularly limited. The electron transport layer is used to improve the efficiency of electron transfer from the photoelectric conversion layer to the electrode and to block the transfer of holes.

[0115] Specific examples of semiconductors forming the electron transport layer include metal oxides such as tin oxide (SnO, SnO2, SnO3, etc.), titanium oxide (TiO2, etc.), tungsten oxide (WO2, WO3, W2O3, etc.), zinc oxide (ZnO), niobium oxide (Nb2O5, etc.), tantalum oxide (Ta2O5, etc.), yttrium oxide (Y2O3, etc.), and strontium titanate (SrTiO3, 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 single-element semiconductors such as silicon and germanium. Two or more of these semiconductors may be used. In the present invention, it is preferred to use one or more selected from tin oxide, titanium oxide, and zinc oxide as the semiconductor.

[0116] For the formation of the electron transport layer, a paste containing a commercially available product of the above-mentioned semiconductor fine particles (electron transport layer coating solution) can be used, or a paste prepared by dispersing commercially available semiconductor fine powder in a solvent can be used. Specific examples of solvents used in the preparation of the paste include: water; alcohol solvents such as methanol, ethanol, and isopropanol; ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; hydrocarbon solvents such as n-hexane, cyclohexane, benzene, and toluene, but are not limited thereto. In addition, these solvents can also be used in the form of a mixed solvent of two or more.

[0117] As a method for dispersing semiconductor fine powder in a solvent, a method using a disperser such as a ball mill, a paint conditioner, a vertical bead mill, a horizontal bead mill, and an attritor can be cited. The powder can be ground in advance using a mortar. When preparing the paste, a surfactant is preferably added to prevent aggregation of the semiconductor fine particles, and a thickener such as polyethylene glycol is preferably added to increase the viscosity.

[0118] The electron transport layer can be formed by a known film-forming method according to the material used. As the film-forming method of the electron transport layer, the following methods can be cited: a method of forming a film on a conductive substrate by a wet coating method such as a spin coating method, an inkjet method, a doctor blade film-forming method (doctorblade method), a drop casting method (dropcast method), a scraper (squeegee method), a screen printing method, a reverse roll coating method, a gravure coating method, a kiss coating method, a roller brush coating method, a spray coating method, an air knife coating method, a wire rod coating method, a tube scraper method, an impregnation coating method and a flow coating method, and then the solvent and additives are removed by firing to form a film; a method of forming a film by a sputtering method, a vapor deposition method, an electrodeposition method, an electrolysis method and a microwave irradiation method, etc., but it is not limited thereto. In the present invention, it is preferred to use the electron transport layer coating liquid prepared by the above method to form a film by a spin coating method, but it is not limited thereto. In addition, the conditions for spin coating can be appropriately set. The atmosphere in which the film is formed is not particularly limited and may be in the air.

[0119] Regarding the thickness of the electron transport layer, from the perspective of further improving the photoelectric conversion efficiency, when a dense electron transport layer is used, the thickness of the electron transport layer is generally preferably 5 nm to 100 nm, and more preferably 10 nm to 50 nm. In the present invention, when a porous (mesoporous) metal oxide is used in addition to a dense layer, its thickness is generally preferably 20 to 200 nm or less, and more preferably 50 to 150 nm.

[0120] <Photoelectric conversion layer>

[0121] The photoelectric conversion element of the present invention is preferably Figure 1 A photoelectric conversion layer (perovskite layer) 3 is formed on the electron transport layer 2 shown above.

[0122] When the photoelectric conversion element of the present invention is a perovskite type, a series of materials having a structure represented by the general formula ABX3 can be cited as the perovskite material used in the photoelectric conversion layer. Here, A, B, and X represent an organic cation or a monovalent metal cation, a metal cation, and a halide anion, respectively. As an example, A=K + , Rb + 、Cs + 、CH3NH3 +(hereinafter, MA: methylammonium), NH=CHNH2 + (hereinafter, FA: formamidinium) or CH3CH2NH3 + (hereinafter, EA: ethylammonium); B=Pb 2+ or Sn 2+ ; X=I - or Br - Specifically, perovskite materials represented by the compositions of MAPbI3, FAPbI3, EAPbI3, CsPbI3, MASnI3, FASnI3, EASnI3, MAPbBr3, FAPbBr3, EAPbBr3, MASnBr3, FASnBr3, and EASnBr3; and perovskite materials composed of mixed cations and mixed anions represented by the compositions of K(FAMA)Pb(IBr)3, Rb(FAMA)Pb(IBr)3, and Cs(FAMA)Pb(IBr)3, but are not limited thereto. Two or more of these perovskite materials may be used in combination. In addition, the photoelectric conversion layer may contain a light absorber other than the perovskite material.

[0123] As a method for forming the photoelectric conversion layer (perovskite layer) of the photoelectric conversion element of the present invention using a coating liquid, any coating method can be used, and the same method as the film forming method of the electron transport layer can be used. The perovskite layer can be produced by forming a coating film using a precursor solution of the perovskite material and then heating it.

[0124] A commercially available product can be used as the perovskite precursor. In the present invention, a precursor prepared by mixing lead halide, methylammonium halide, formamidine halide, and cesium halide in a desired composition is preferably used, but the present invention is not limited thereto.

[0125] As the solvent of the perovskite precursor solution, from the viewpoint of precursor solubility, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO) and γ-butyrolactone can be listed, but are not limited thereto. In addition, these solvents can be mixed and used in combination of two or more, and preferably a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide is used.

[0126] The atmosphere during the film formation of the photoelectric conversion layer (perovskite layer) is preferably a dry atmosphere, more preferably a dry inert gas atmosphere such as a glove box, from the viewpoint of being able to reproducibly manufacture a high-efficiency photoelectric conversion element by preventing the incorporation of moisture. In addition, it is preferred to use a solvent that has been dehydrated by molecular sieves or the like to have a low water content.

[0127] From the perspective of efficiently generating a perovskite material from a precursor, the temperature when heating the photoelectric conversion layer (perovskite layer) using a hot plate or the like is preferably 50 to 200° C., more preferably 70 to 150° C. The heating time is preferably 10 to 90 minutes, more preferably 10 to 60 minutes.

[0128] From the perspective of further suppressing performance degradation caused by defects and peeling, and from the perspective of ensuring that the photoelectric conversion layer has sufficient light absorptivity and the element resistance is not too high, the film thickness of the photoelectric conversion layer (perovskite layer) is preferably 50 to 1000 nm, more preferably 300 to 700 nm.

[0129] Hole transport layer

[0130] In the photoelectric conversion element of the present invention, Figure 1 The hole transport layer 4 shown is a layer that has the function of transporting holes and is located between the photoelectric conversion layer (perovskite layer) 3 and the counter electrode 5. The hole transport layer is used to improve the efficiency of hole movement from the photoelectric conversion layer to the electrode and block the movement of electrons. For example, conductors, semiconductors, and organic hole transport materials can be used in the hole transport layer, and additives can also be included to further improve the hole transport properties.

[0131] The hole transport layer in the photoelectric conversion element of the present invention is a layer containing the compound represented by the above-mentioned general formula (1) as a hole transport material. The hole transport layer may contain two or more compounds represented by the above-mentioned general formula (1) in combination, or may contain other hole transport materials not belonging to the present invention.

[0132] Specific examples of other hole transport materials that are not hole transport materials of the present invention include: compound semiconductors containing monovalent copper, such as CuI, CuInSe2, and CuS; compounds containing metals other than copper, such as GaP, NiO, CoO, FeO, Bi2O3, MoO2, and Cr2O3. These oxide metals can be mixed in the hole transport layer or stacked on the hole transport material. As organic hole transport materials, for example, 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; polyaniline derivatives, etc.

[0133] As a method for forming the hole transport layer of the photoelectric conversion element of the present invention using a coating liquid, any coating method can be used, and examples thereof include the same method as the film formation method of the electron transport layer.

[0134] Examples of the solvent used in the hole transport layer coating liquid include aromatic organic solvents such as benzene, toluene, xylene, mesitylene, tetralin (1,2,3,4-tetralin), monochlorobenzene (chlorobenzene), o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, and nitrobenzene; halogenated alkyl organic solvents such as dichloromethane, chloroform, 1,2-dichloroethane, 1,1,2-trichloroethane, and dichloromethane; and nitriles such as benzonitrile and acetonitrile. The present invention also includes, but is not limited to, ether solvents such as tetrahydrofuran, 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. In addition, two or more of the above solvents may be mixed and the solvent used may be selected according to the hole transport material used. In particular, aromatic organic solvents and halogenated alkyl organic solvents are preferably used.

[0135] In the photoelectric conversion element of the present invention, from the viewpoint of further improving the photoelectric conversion efficiency, the thickness of the hole transport layer is preferably 5 to 500 nm, more preferably 10 to 250 nm.

[0136] The atmosphere during the formation of the hole transport layer is preferably a dry atmosphere from the viewpoint of being able to reproducibly produce a highly efficient photoelectric conversion element by preventing the incorporation of moisture. Furthermore, it is preferred to use a dehydrated solvent having a moisture content of 10 ppm or less.

[0137] <additive>

[0138] In the photoelectric conversion element of the present invention, as an additive to the hole transport layer, a dopant (or oxidant) or a basic compound (or basic additive) may be contained. Including an additive in the hole transport layer and increasing the carrier concentration of the hole transport material in the hole transport layer (doping) will lead 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 an additive, it is preferred that the additive is 3.5 equivalents or less relative to 1 equivalent of the hole transport material.

[0139] When the hole transport layer contains a dopant, specific examples of the dopant include lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), silver bis(trifluoromethanesulfonyl)imide, tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridinium)cobalt(III)tris[bis(trifluoromethane)sulfonimide] (FK209), NOSbF6, SbCl5, and SbF5. In the present invention, lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) is preferably used, but the present invention is not limited to this.

[0140] 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 1 equivalent of the hole transport material contained in the hole transport layer.

[0141] When a basic compound is included in the hole transport layer, specific examples include 4-tert-butylpyridine (tBP), 2-methylpyridine, and 2,6-lutidine. Basic compounds are often used in conjunction with a dopant. In the present invention, it is desirable to use a basic compound in conjunction with a dopant, and 4-tert-butylpyridine is preferred.

[0142] When a basic compound is used, the amount thereof is preferably 5 equivalents or less, more preferably 3 equivalents or less, relative to 1 equivalent of the hole transport material contained in the hole transport layer.

[0143] Counter electrode

[0144] In the photoelectric conversion element of the present invention, Figure 1 The counter electrode 5 shown is a layer disposed opposite to the conductive support 1 and formed on the hole transport layer 4, and is used to exchange charge with the hole transport layer. In the photoelectric conversion element of the present invention, a metal electrode is preferably provided on the hole transport layer 4 as the counter electrode. However, an electron blocking layer formed of an organic material or an inorganic compound semiconductor may be added between the hole transport layer 4 and the counter electrode 5.

[0145] 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, as well as alloys thereof. Silver or silver alloys are preferred because they exhibit high electrical conductivity even in thin films. Silver alloys are preferably silver-gold alloys, silver-copper alloys, silver-palladium alloys, silver-copper-palladium alloys, and silver-platinum alloys, in order to reduce susceptibility to sulfidation and chlorination and improve thin film stability.

[0146] The counter electrode is preferably formed of a material by a method such as vapor deposition.

[0147] When a metal electrode is used as the counter electrode, in order to obtain good conductivity, the film thickness is preferably 10 nm or more, more preferably 50 nm or more.

[0148] In the photoelectric conversion element of the present invention, the conductive support constitutes a cathode, and the counter electrode constitutes an anode. Light such as sunlight is preferably irradiated from the conductive support side. By irradiation with sunlight, the photoelectric conversion layer (perovskite layer) absorbs light and becomes excited, generating electrons and holes. The electrons move to the electrode via the electron transport layer, and the holes move to the electrode via the hole transport layer, thereby circulating current and functioning as a photoelectric conversion element.

[0149] 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 represents the current flowing into the space between the two terminals per 1 cm when the output terminals are short-circuited. 2 The open-circuit voltage represents the voltage between the two terminals when the output terminals are open. Furthermore, the fill factor is the maximum output (the product of current and voltage) divided by the product of short-circuit current density and open-circuit voltage, and is primarily affected by internal resistance. The photoelectric conversion efficiency is the maximum output (W) divided by the power per 1cm 2 The value obtained by multiplying the light intensity (W) by 100 and expressing it as a percentage is obtained.

[0150] The photoelectric conversion element of the present invention can be applied to perovskite solar cells, various optical sensors, and the like. The photoelectric conversion element comprising a hole transport material containing a compound represented by the general formula (1) as a hole transport layer is a single cell. The desired number of cells are arranged to form a module, and predetermined electrical wiring is provided to obtain a perovskite solar cell.

[0151] Although preferred embodiments have been described above, the present invention is not limited thereto and can be appropriately modified without departing from the scope of the present invention.

[0152] Example

[0153] Hereinafter, the present invention will be specifically described with reference to the accompanying drawings by way of examples, but the present invention is not limited to the following examples. 1 The results were analyzed using H-NMR (Nuclear Magnetic Resonance System manufactured by JEOL Ltd., Model JNM-ECZ400S / L1).

[0154] [Synthesis Example 1] Synthesis of Compound (A-2)

[0155] 2,7-Dibromofluorenone (0.63 g, manufactured by Tokyo Chemical Industry Co., Ltd.), [4-[bis(4-methoxyphenyl)amino]phenyl]boric acid (1.50 g, manufactured by TCI Corporation), tetrakistriphenylphosphine palladium (0) (0.09 g, manufactured by Kanto Chemical Co., Ltd.), potassium carbonate (0.68 g, manufactured by Kanto Chemical Co., Ltd.), toluene (10 mL), ethanol (3.5 mL), and water (3.5 mL) were added to the reaction vessel and degassed under reduced pressure. Under an argon atmosphere, the mixture was heated under reflux and stirred for 6 hours. After the reaction was completed, toluene (10 mL) and water (20 mL) were added. The mixture was separated and the organic layer was washed twice with water (30 mL). The organic layer was concentrated and the crude product was purified with a silica gel column (toluene) to obtain a reddish purple powder of the compound represented by the following formula (A-2) (yield: 1.44 g, yield: 98%).

[0156] 1 H-NMR (400MHz, CDCl3): δ (ppm) = 3.81 (12H), 6.85 (8H), 6.98 (4H), 7.10 (8H), 7.43 (4H), 7.53 (2H), 7.67 (2H), 7.86 (2H).

[0157] [Chemical Formula 22]

[0158]

[0159] [Synthesis Example 2] Synthesis of Compound (A-15)

[0160] The compound of the above formula (A-2) (0.60 g), malononitrile (0.20 g, manufactured by Tokyo Chemical Industry Co., Ltd.), and 25 mL of THF were added to the reaction vessel and stirred under an argon atmosphere. Acetic acid (2.4 mL, manufactured by Kanto Chemical Co., Ltd.) and pyridine (2.4 mL, manufactured by Nakalai Tesque Co., Ltd.) were added thereto and stirred under heating and reflux for 16 hours. After the reaction was completed, the reaction solution was added to a beaker containing 300 mL of water. It was filtered and washed with 30 mL of water and 20 mL of methanol. The crude product was purified using a silica gel column (toluene: chloroform = 4:1) to obtain a black-green powder of the compound represented by the following formula (A-15) (yield: 0.54 g, yield: 84%).

[0161] 1 H-NMR (400MHz, CDCl3): δ (ppm) = 3.81 (12H), 6.86 (8H), 6.98 (4H), 7.10 (8H), 7.43 (4H), 7.53 (2H), 7.65 (2H), 8.57 (2H).

[0162] [Chemical Formula 23]

[0163]

[0164] [Synthesis Example 3] Synthesis of Compound (A-28)

[0165] Into the reaction vessel, the compound of the above formula (A-2) (0.6 g), diethyl malonate (0.37 g, manufactured by Tokyo Chemical Industry Co., Ltd.), and THF (14 mL) were added and stirred under an argon atmosphere. Cool to below 5°C in an ice bath, and add pyridine (1 mL). Cool again to below 5°C, and add titanium tetrachloride (0.5 mL, manufactured by Wako Pure Chemical Industries, Ltd.). Thereafter, the temperature was raised to room temperature, and stirred at room temperature for 17 hours. After the reaction was completed, the reaction solution was poured into a beaker to which 200 mL of water was added, and toluene (30 mL) was added thereto. The liquid was separated, and the organic layer was dried over magnesium sulfate and then concentrated. The crude product was purified with a silica gel column (toluene) to obtain a reddish purple powder of the compound represented by the following formula (A-28) (yield: 0.50 g, yield: 71%).

[0166] 1 H-NMR (400MHz, CDCl3): δ (ppm) = 1.37 (6H), 3.81 (12H), 4.43 (4H), 6.86 (8H), 6.99 (4H), 7.11 (8H), 7.40 (4H), 7.56 (2H), 7.60 (2H), 8.04 (2H).

[0167] [Chemical Formula 24]

[0168]

[0169] [Synthesis Example 4] Synthesis of Compound (A-41)

[0170] Into the reaction vessel, the compound of the above formula (A-2) (0.65 g), methyl cyanoacetate (0.33 g, manufactured by Tokyo Chemical Industry Co., Ltd.), and THF (25 mL) were added and stirred under an argon atmosphere. Cool to below 5°C in an ice bath, and add pyridine (1 mL). Cool again to below 5°C, and add titanium tetrachloride (0.55 mL, manufactured by Wako Pure Chemical Industries, Ltd.). After that, the temperature was raised to room temperature, stirred at room temperature for 8 hours, and then stirred under heating reflux for 2 hours. After the reaction was completed, the reaction solution was poured into a beaker to which water (200 mL) was added, and toluene (30 mL) was added thereto. The liquid was separated, and the organic layer was dried over magnesium sulfate and then concentrated. The crude product was purified with a silica gel column (toluene) to obtain a black-green powder of the compound represented by the following formula (A-41) (yield: 0.65 g, yield: 90%).

[0171] 1H-NMR (400MHz, CDCl3): δ (ppm) = 3.81 (12H), 4.10 (3H), 6.86 (8H), 6.99 (4H) , 7.11(8H), 7.40(2H), 7.46(2H), 7.50(2H), 7.60(2H), 8.26(1H), 8.78(1H).

[0172] [Chemical Formula 25]

[0173]

[0174] [Synthesis Example 5] Synthesis of Compound (A-1)

[0175] 2,7-Dibromofluorenone (0.75 g, manufactured by Tokyo Chemical Industry Co., Ltd.), 4-(diphenylamino)phenylboronic acid (1.48 g, manufactured by Sigma Aldrich Co., Ltd.), tetrakistriphenylphosphine palladium (0) (0.10 g, manufactured by Kanto Chemical Co., Ltd.), potassium carbonate (0.80 g, manufactured by Kanto Chemical Co., Ltd.), toluene (12 mL), ethanol (4.0 mL), and water (4.0 mL) were added to the reaction vessel and degassed under reduced pressure. Under an argon atmosphere, the mixture was stirred for 4 hours under heating and reflux. After the reaction was completed, the reaction solution was added to a beaker containing water (100 mL), and 30 mL of toluene was added thereto. The liquid was separated, and the organic layer was dried over magnesium sulfate and then concentrated. The crude product was purified using a silica gel column (toluene). Thereafter, recrystallization was performed using toluene to obtain a red powder of the compound represented by the following formula (A-1) (yield: 1.48 g, yield: 100%).

[0176] 1 H-NMR (400MHz, DMSO-d6): δ (ppm) = 7.0-7.1 (16H), 7.35 (8H), 7.71 (4H), 7.85 (2H), 7.92 (4H).

[0177] [Chemical Formula 26]

[0178]

[0179] [Synthesis Example 6] Synthesis of Compound (A-27)

[0180] Into the reaction vessel, the compound of the above formula (A-1) (0.6 g), diethyl malonate (0.82 g, manufactured by TCI), and THF (27 mL) were added and stirred under an argon atmosphere. Cool to below 5°C in an ice bath, and add pyridine (1.1 mL). Cool again to below 5°C, and add titanium tetrachloride (0.6 mL, manufactured by Wako Pure Chemical Industries, Ltd.). Thereafter, the temperature was raised to room temperature, and stirred at room temperature for 17 hours. After the reaction was completed, the reaction solution was poured into a beaker to which 200 mL of water was added, and toluene (30 mL) was added thereto. The liquid was separated, and the organic layer was dried over magnesium sulfate and then concentrated. The crude product was purified with a silica gel column (toluene) to obtain a red powder of the compound represented by the following formula (A-27) (yield: 0.52 g, yield: 71%).

[0181] 1 H-NMR (400MHz, DMSO-d6): δ (ppm) = 1.38 (6H), 4.45 (4H), 7.06 (4H), 7.13-7.16 (12H), 7.29 (8H), 7.46 (4H), 7.61 (4H), 7.07 (2H).

[0182] [Chemical Formula 27]

[0183]

[0184] [Synthesis Example 7] Synthesis of Compound (A-14)

[0185] The compound of the above formula (A-1) (0.60 g), malononitrile (0.23 g, manufactured by Tokyo Chemical Industry Co., Ltd.), and THF (50 mL) were added to a reaction vessel and stirred under an argon atmosphere. Acetic acid (2.8 mL, manufactured by Kanto Chemical Co., Ltd.) and pyridine (2.8 mL, manufactured by Nakalai Tesque Co., Ltd.) were added thereto and stirred under heating and reflux for 6 hours. After the reaction was completed, the reaction solution was added to a beaker to which water (200 mL) was added. It was filtered and washed with water (20 mL) and methanol (20 mL). The crude product was recrystallized (chloroform) to obtain a black-green powder of the compound represented by the following formula (A-14) (yield: 0.58 g, yield: 91%).

[0186] 1 H-NMR (400MHz, THF-d8): δ (ppm) = 7.0-7.1 (16H), 7.35 (8H), 7.71 (4H), 7.92 (4H), 8.56 (2H).

[0187] [Chemical Formula 28]

[0188]

[0189] [Synthesis Example 8] Synthesis of Compound (A-67)

[0190] 2,7-Dibromofluorenone (0.47 g, manufactured by Tokyo Chemical Industry Co., Ltd.), a compound of the following formula (9) (2.71 g), tetrakistriphenylphosphine palladium (0) (0.065 g, manufactured by Kanto Chemical Industry Co., Ltd.), potassium carbonate (0.51 g, manufactured by Kanto Chemical Industry Co., Ltd.), toluene (7.5 mL), ethanol (2.5 mL), and water (2.5 mL) were added to a reaction vessel and degassed under reduced pressure. Under an argon atmosphere, the mixture was stirred under reflux for 13 hours. After the reaction was completed, toluene (20 mL) and water (10 mL) were added. The mixture was separated, the aqueous layer was extracted twice with toluene (20 mL), and the organic layer was concentrated. The crude product was purified using a silica gel column (toluene / ethyl acetate = 50 / 1 (volume ratio)) to obtain a red powder of the compound represented by the following formula (A-67) (yield: 1.76 g, yield: 80%).

[0191] 1 H-NMR (400MHz, DMSO-d6): δ (ppm) = 3.65 (24H), 6.75 (16H), 6.83 (16H), 7.02 (4H), 7.19 (4H), 7.58 (4H), 7.63 (4H), 7.88 (4H), 7.95 (6H).

[0192] [Chemical Formula 29]

[0193]

[0194] [Synthesis Example 9] Synthesis of Compound (A-82)

[0195] Into a reaction vessel, a compound of the above formula (A-67) (0.70 g), malononitrile (0.12 g, manufactured by Tokyo Chemical Industry Co., Ltd.), and THF (18 mL) were added and stirred under an argon atmosphere. Acetic acid (1.6 mL, manufactured by Kanto Chemical Co., Ltd.) and pyridine (1.6 mL, manufactured by Nakalai Tesque Co., Ltd.) were added thereto. The mixture was stirred for 14 hours under heating and reflux. After the reaction was completed, the reaction solution was added to a beaker containing water (200 mL). It was filtered and washed with water (30 mL) and methanol (20 mL). The crude product was recrystallized (chloroform / acetone) to obtain a black-green powder of the compound represented by the following formula (A-82) (yield: 0.67 g, yield: 94%).

[0196] 1H-NMR (400MHz, THF-d8): δ (ppm) = 3.68 (24H), 6.72 (16H), 6.91 (16H), 7.07 (4H), 7.34 (4H), 7.66 (4H), 7.74 (4H), 7.89 (2H), 7.99 (6H), 8.81 (2H).

[0197] [Chemical formula 30]

[0198]

[0199] [Synthesis Example 10] Synthesis of Compound (A-97)

[0200] 2,7-Dibromofluorenone (0.47 g), a compound of the following formula (10) (2.62 g), tetrakis(triphenylphosphine)palladium(0) (0.065 g, manufactured by Kanto Chemical Co., Ltd.), potassium carbonate (0.51 g, manufactured by Kanto Chemical Co., Ltd.), toluene (7.5 mL), ethanol (2.5 mL), and water (2.5 mL) were added to a reaction vessel and degassed under reduced pressure. Under an argon atmosphere, the mixture was stirred under reflux for 8 hours. After the reaction was completed, toluene (20 mL) and water (10 mL) were added. The mixture was separated, the aqueous layer was extracted twice with toluene (20 mL), and the organic layer was concentrated. The crude product was purified using a silica gel column (toluene:ethyl acetate = 50 / 1 (volume ratio)) to obtain a red powder of the compound represented by the following formula (A-97) (yield: 1.95 g, yield: 86%).

[0201] 1 H-NMR (400MHz, THF-d8): δ (ppm) = 3.73 (24H), 6.59-6.65 (8H), 6.74 (4H), 6. 80(16H), 6.97(16H), 7.35(4H), 7.75(2H), 7.80(4H), 7.86(2H), 7.94(2H).

[0202] [Chemical Formula 31]

[0203]

[0204] [Synthesis Example 11] Synthesis of Compound (A-113)

[0205] Into a reaction vessel, the compound of the above formula (A-97) (0.60 g), malononitrile (0.10 g, manufactured by Tokyo Chemical Industry Co., Ltd.), and THF (15 mL) were added and stirred under an argon atmosphere. Acetic acid (1.3 mL, manufactured by Kanto Chemical Co., Ltd.) and pyridine (1.3 mL, manufactured by Nakalai Tesque Co., Ltd.) were added thereto. Stirring was carried out under heating and reflux for 20 hours. After the reaction was completed, the reaction solution was poured into water (200 mL). It 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 a green powder of the compound represented by the following formula (A-113) (yield: 0.56 g, yield: 90%).

[0206] 1 H-NMR (400MHz, THF-d8): δ (ppm) = 3.73 (24H), 6.59-6.65 (8H), 6.74 (4H), 6. 80(16H), 6.97(16H), 7.35(4H), 7.75(2H), 7.80(4H), 7.86(2H), 8.94(2H).

[0207] [Chemical Formula 32]

[0208]

[0209] [Synthesis Example 12] Synthesis of Compound (A-132)

[0210] 2,7-Dibromofluorenone (0.47 g), a compound of the following formula (11) (2.57 g), tetrakis(triphenylphosphine)palladium(0) (0.065 g, manufactured by Kanto Chemical Co., Ltd.), potassium carbonate (0.51 g, manufactured by Kanto Chemical Co., Ltd.), toluene (7.5 mL), ethanol (2.5 mL), and water (2.5 mL) were placed in a reaction vessel and 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, the aqueous layer was extracted twice with toluene (20 mL), and the organic layer was concentrated. The crude product was purified using a silica gel column (toluene / ethyl acetate = 50 / 1 (volume ratio)) to obtain a red powder of the compound represented by the following formula (A-132) (yield: 1.67 g, yield: 75%).

[0211] 1 H-NMR (400MHz, THF-d8): δ (ppm) = 3.75 (24H), 6.60-6.66 (8H), 6.76 (4H), 6. 82(16H), 6.97(16H), 7.36(4H), 7.78(2H), 7.83(4H), 7.87(2H), 7.95(2H).

[0212] [Chemical Formula 33]

[0213]

[0214] [Synthesis Example 13] Synthesis of Compound (A-144)

[0215] Into a reaction vessel, the compound of the above formula (A-132) (0.60 g), malononitrile (0.10 g, manufactured by Tokyo Chemical Industry Co., Ltd.), and THF (15 mL) were added and stirred under an argon atmosphere. Acetic acid (1.3 mL, manufactured by Kanto Chemical Co., Ltd.) and pyridine (1.3 mL, manufactured by Nakalai Tesque Co., Ltd.) were added thereto. Stirring was carried out under heating and reflux for 15 hours. After the reaction was completed, the reaction solution was poured into water (200 mL). It was filtered and washed with water (30 mL) and methanol (20 mL). The crude product was recrystallized (chloroform / acetone) to obtain a green powder of the compound represented by the following formula (A-144) (yield: 0.54 g, yield: 88%).

[0216] 1 H-NMR (400MHz, THF-d8): δ (ppm) = 3.75 (24H), 6.60-6.66 (8H), 6.76 (4H), 6. 82(16H), 6.97(16H), 7.36(4H), 7.78(2H), 7.83(4H), 7.87(2H), 8.95(2H).

[0217] [Chemical Formula 34]

[0218]

[0219] [Synthesis Example 14] Synthesis of Compound (A-54)

[0220] Into the reaction vessel, the compound of the above formula (A-2) (0.6 g), 1,3-diethylthiobarbituric acid (0.38 g, manufactured by Wako Pure Chemical Industries, Ltd.), and THF (24 mL) were added and stirred under an argon atmosphere. Piperidine (0.07 mL) was added thereto. The temperature was raised and heated to reflux for 4 hours. After the reaction was completed, the reaction solution was poured into a beaker to which 300 mL of water was added, filtered, and washed with 30 mL of water and 30 mL of methanol. The crude product was purified with a silica gel column (toluene) to obtain a black-green powder of the compound represented by the following formula (A-54) (yield: 0.44 g, yield: 60%).

[0221] 1H-NMR (400MHz, CDCl3): δ (ppm) = 3.81 (12H), 6.85 (8H), 6.98 (4H), 7.10 (8H), 7.43 (4H), 7.53 (2H), 7.67 (2H), 8.41 (2H).

[0222] [Chemical Formula 35]

[0223]

[0224] Synthesis of compound (A-8)

[0225] [Synthesis Example 15]

[0226] 2,7-Dibromofluorenone (0.68 g, manufactured by Tokyo Chemical Industry Co., Ltd.), a compound of the following formula (12) (2.52 g), potassium carbonate (0.72 g, manufactured by Kanto Chemical Industry Co., Ltd.), tetrakistriphenylphosphine palladium (0.09 g, manufactured by Kanto Chemical Industry Co., Ltd.), toluene (11 mL), ethanol (3 mL), and water (3 mL) were added to a reaction vessel and degassed under reduced pressure. The mixture was stirred under reflux for 10 hours. After the reaction was completed, the reaction solution was added to a beaker containing water (100 mL). Toluene (20 mL) was added thereto, 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: hexane = 2 / 1 (volume ratio)) to obtain a red powder of the compound represented by the following formula (A-8) (yield: 1.79 g, yield: 84%).

[0227] 1 H-NMR (400MHz, CDCl3): δ (ppm) = 0.92 (12H), 1.31-1.36 (16H), 1.40-1.47 (8H), 1.74-1.81 ( 8H), 3.94(8H), 6.84(8H), 6.98(4H), 7.08(8H), 7.43(4H), 7.52(2H), 7.60(2H), 7.86(2H).

[0228] [Chemical Formula 36]

[0229]

[0230] [Synthesis Example 16] Synthesis of Compound (A-20)

[0231] The compound of the above formula (A-8) (0.68 g), malononitrile (0.22 g, manufactured by Tokyo Chemical Industry Co., Ltd.), and THF (26 mL) were added to the reaction vessel and stirred under an argon atmosphere. A mixed solution of acetic acid and pyridine (volume ratio = 1:1) (4.6 mL) was added thereto and stirred under heating and reflux for 19 hours. After the reaction was completed, the reaction solution was poured into water (150 mL). Toluene (20 mL) was added thereto and the liquids were separated. The organic layer was dried over magnesium sulfate and then concentrated. The crude product was purified by a silica gel column (toluene) to obtain a black-green solid of the compound represented by the following formula (A-20) (yield: 0.59 g, yield: 83%).

[0232] 1 H-NMR (400MHz, CDCl3): δ (ppm) = 0.92 (12H), 1.31-1.36 (16H), 1.40-1.47 (8H), 1.74-1.81 ( 8H), 3.94(8H), 6.84(8H), 6.98(4H), 7.08(8H), 7.43(4H), 7.52(2H), 7.65(2H), 8.57(2H).

[0233] [Chemical Formula 37]

[0234]

[0235] [Synthesis Example 17] Synthesis of Compound (A-11)

[0236] Into a reaction vessel, a compound represented by the following formula (13) (1.10 g), [4-[bis(4-methoxyphenyl)amino]phenyl]boronic acid (1.75 g, manufactured by Tokyo Chemical Industry Co., Ltd.), potassium carbonate (0.82 g, manufactured by Kanto Chemical Industry Co., Ltd.), tetrakistriphenylphosphine palladium (0.10 g, manufactured by Kanto Chemical Industry Co., Ltd.), toluene (18 mL), ethanol (5.1 mL), and water (5.1 mL) were added, and degassed under reduced pressure. After heating and reflux for 6 hours, the reaction was cooled to below 40°C, and water (10 mL) and methanol (10 mL) were added. The mixture was filtered, washed with methanol (10 mL), and then dried. The crude product was purified using a silica gel column (chloroform:toluene = 50 / 1 (volume ratio)) to obtain a red powder of the compound represented by the following formula (A-11) (yield: 1.79 g, yield: 86%).

[0237] 1 H-NMR (400MHz, CDCl3): δ (ppm) = 3.81 (12H), 6.86 (8H), 6.93 (4H), 7.09 (8H), 7.18 (2H), 7.34 (2H), 7.42 (4H), 7.50 (2H), 7.71 (2H), 7.92 (2H).

[0238] [Chemical Formula 38]

[0239]

[0240] [Synthesis Example 18] Synthesis of Compound (A-23)

[0241] The compound represented by the above formula (A-11) (0.73 g), malononitrile (0.22 g, manufactured by Tokyo Chemical Industry Co., Ltd.), and THF (26 mL) were added to the reaction vessel and stirred under an argon atmosphere. A mixed solution of acetic acid and pyridine (volume ratio = 1:1) (4.6 mL) was added thereto and heated under reflux for 15 hours. After the reaction was completed, the reaction solution was poured into water (150 mL). It was filtered, washed with methanol (20 mL), and then dried. The crude product was purified with a silica gel column (chloroform) to obtain a black-green solid of the compound represented by the following formula (A-23) (yield: 0.63 g, yield: 83%).

[0242] 1 H-NMR (400MHz, CDCl3): δ (ppm) = 3.81 (12H), 6.87 (8H), 6.93 (4H), 7.09 (8H), 7.18 (2H), 7.34 (2H), 7.42 (4H), 7.60 (2H), 7.90 (2H), 8.65 (2H).

[0243] [Chemical Formula 39]

[0244]

[0245] [Synthesis Example 19] Synthesis of Compound (A-36)

[0246] Into the reaction vessel, the compound of the above formula (A-11) (0.45 g), diethyl malonate (0.42 mL, manufactured by Tokyo Chemical Industry Co., Ltd.), and THF (15 mL) were added and stirred under an argon atmosphere. Cool to below 5°C in an ice bath, and add pyridine (0.63 mL). Cool again to below 5°C, and add titanium tetrachloride (0.32 mL, manufactured by Wako Pure Chemical Industries, Ltd.). Thereafter, the temperature was raised and heated to reflux for 9 hours. After the reaction was completed, the reaction solution was added to a beaker with water (150 mL). It was filtered, washed with water (10 mL) and methanol (30 mL), and dried. The crude product was purified with a silica gel column (chloroform) to obtain a brown powder of the compound represented by the following formula (A-36) (yield: 0.36 g, yield: 71%).

[0247] 1H-NMR (400MHz, THF-d8): δ (ppm) = 1.39 (6H), 3.78 (12H), 4.50 (4H), 6.83-6 .90(12H), 7.05(8H), 7.24(2H), 7.35(2H), 7.45(4H), 7.71(4H), 8.20(2H).

[0248] [Chemical Formula 40]

[0249]

[0250] [Synthesis Example 20] Synthesis of Compound (A-49)

[0251] Into the reaction vessel, the compound of the above formula (A-11) (0.45 g), methyl cyanoacetate (0.25 mL, manufactured by Tokyo Chemical Industry Co., Ltd.), and THF (15 mL) were added and stirred under an argon atmosphere. Cool to below 5°C in an ice bath, and add pyridine (0.63 mL). Cool again to below 5°C, and add titanium tetrachloride (0.32 mL, manufactured by Wako Pure Chemical Industries, Ltd.). Thereafter, the temperature was raised and heated to reflux for 9 hours. After the reaction was completed, the reaction solution was added to a beaker with water (150 mL). It was filtered, washed with water (10 mL) and methanol (30 mL), and dried. The crude product was purified with a silica gel column (chloroform) to obtain a brown powder of the compound represented by the following formula (A-49) (yield: 0.46 g, yield: 94%).

[0252] 1 H-NMR (400MHz, THF-d8): δ (ppm) = 3.78 (12H), 4.07 (3H), 6.84-6.89 (12H), 7.05 ( 8H), 7.24(2H), 7.37(1H), 7.40(1H), 7.45(4H), 7.71(4H), 8.43(1H), 8.92(1H).

[0253] [Chemical Formula 41]

[0254]

[0255] [Synthesis Example 21] Synthesis of Compound (A-79)

[0256] The compound of the above formula (13) (0.50 g), the compound of the above formula (9) (1.89 g), potassium carbonate (0.37 g, manufactured by Kanto Chemical Co., Ltd.), tetrakistriphenylphosphine palladium (0.05 g, manufactured by Kanto Chemical Co., Ltd.), toluene (10 mL), ethanol (2.3 mL), and water (2.3 mL) were placed in a reaction vessel and degassed under reduced pressure. The mixture was heated under reflux for 13 hours. After the reaction was completed, the reaction solution was poured into a beaker containing water (100 mL). The mixture was filtered, washed with water (10 mL) and methanol (30 mL), and dried. The crude product was purified using a silica gel column (toluene:ethyl acetate = 30 / 1 (volume ratio)) to obtain a reddish-brown powder of the compound represented by the following formula (A-79) (yield: 1.23 g, yield: 71%).

[0257] 1 H-NMR (400MHz, DMSO-d6): δ (ppm) = 3.70 (24H), 6.82 (16H), 6.88 (16H), 7.09 (4 H), 7.32(4H), 7.64(6H), 7.67(4H), 7.70(2H), 7.84(2H), 7.89(2H), 7.94(6H).

[0258] [Chemical Formula 42]

[0259]

[0260] [Synthesis Example 22] Synthesis of Compound (A-95)

[0261] The compound of the above formula (A-79) (0.66 g), malononitrile (0.11 g, manufactured by Tokyo Chemical Industry Co., Ltd.), and THF (15 mL) were added to the reaction vessel and stirred under an argon atmosphere. A mixed solution of acetic acid and pyridine (volume ratio = 1:1) (2.3 mL) was added thereto and heated under reflux for 19 hours. After the reaction was completed, the reaction solution was poured into water (100 mL). It was filtered, washed with methanol (20 mL), and then dried. The crude product was purified by recrystallization (chloroform) to obtain a black-green solid of the compound represented by the following formula (A-95) (yield: 0.54 g, yield: 80%).

[0262] 1 H-NMR (400MHz, DMSO-d6): δ (ppm) = 3.70 (24H), 6.82 (16H), 6.88 (16H), 7.09 (4 H), 7.32(4H), 7.65(6H), 7.67(4H), 7.80(2H), 7.98(2H), 8.01(2H), 8.12(6H).

[0263] [Chemical Formula 43]

[0264]

[0265] [Synthesis Example 23] Synthesis of Compound (A-96)

[0266] Into the reaction vessel, the compound of the above formula (A-79) (0.40 g), diethyl malonate (0.20 mL, manufactured by Tokyo Chemical Industry Co., Ltd.), and THF (9 mL) were added and stirred under an argon atmosphere. Cool to below 5°C in an ice bath, and add pyridine (0.31 mL). Cool again to below 5°C, and add titanium tetrachloride (0.16 mL, manufactured by Wako Pure Chemical Industries, Ltd.). Thereafter, the temperature was raised and heated to reflux for 6 hours. After the reaction was completed, the reaction solution was added to a beaker containing water (150 mL). It was filtered, washed with water (10 mL) and methanol (30 mL), and dried. The crude product was purified with a silica gel column (toluene: ethyl acetate = 20 / 1 (volume ratio)) to obtain a black-green powder of the compound represented by the following formula (A-96) (yield: 0.07 g, yield: 16%).

[0267] 1 H-NMR (400MHz, DMSO-d6): δ (ppm) = 1.42 (6H), 3.78 (12H), 4.52 (4H), 6.83-6.91 (20H), 6.88(16H), 7.40(4H), 7.62(6H), 7.65(4H), 7.68(2H), 7.80(2H), 7.85(2H), 7.89(6H).

[0268] [Chemical Formula 44]

[0269]

[0270] [Synthesis Example 24] Synthesis of Compound (A-83)

[0271] Into the reaction vessel, the compound of the above formula (A-67) (0.30 g), methyl cyanoacetate (0.10 mL, manufactured by Tokyo Chemical Industry Co., Ltd.), and THF (7 mL) were added and stirred under an argon atmosphere. Cool to below 5°C in an ice bath, and add pyridine (0.25 mL). Cool again to below 5°C, and add titanium tetrachloride (0.13 mL, manufactured by Wako Pure Chemical Industries, Ltd.). Thereafter, the temperature was raised and heated to reflux for 9 hours. After the reaction was completed, water (20 mL) and toluene (10 mL) were added for liquid separation. The organic layer was dried over magnesium sulfate and concentrated. The crude product was purified by a silica gel column (toluene: ethyl acetate = 40 / 1 (volume ratio)) to obtain a black-green powder of the compound represented by the following formula (A-83) (yield: 0.22 g, yield: 70%).

[0272] 1 H-NMR (400MHz, THF-d8): δ (ppm) = 3.71 (24H), 4.06 (3H), 6.74 (16H), 6.93 (16H) ), 7.11(4H), 7.33(4H), 7.69-7.76(8H), 7.88-7.99(8H), 8.63(1H), 9.07(1H).

[0273] [Chemical Formula 45]

[0274]

[0275] [Synthesis Example 25] Synthesis of Compound (A-155)

[0276] Into the reaction vessel, the compound of the above formula (A-67) (0.30 g), diethyl malonate (0.18 mL, manufactured by Tokyo Chemical Industry Co., Ltd.), and THF (7 mL) were added and stirred under an argon atmosphere. Cooled to below 5°C in an ice bath, pyridine (0.25 mL) was added. Cooled to below 5°C again, titanium tetrachloride (0.13 mL, manufactured by Wako Pure Chemical Industries, Ltd.) was added. Thereafter, the temperature was raised and heated to reflux for 9 hours. After the reaction was completed, water (20 mL) and toluene (10 mL) were added for liquid separation. The organic layer was dried over magnesium sulfate and concentrated. The crude product was purified by a silica gel column (toluene: ethyl acetate = 50 / 1 (volume ratio)) to obtain a black-green powder of the compound represented by the following formula (A-155) (yield: 0.26 g, yield: 78%).

[0277] 1 H-NMR (400MHz, THF-d8): δ (ppm) = 1.35 (6H), 3.71 (24H), 4.45 (4H), 6.73 (16H) , 6.91(16H), 7.10(4H), 7.35(4H), 7.70-7.72(8H), 7.84-7.91(8H), 8.34(2H).

[0278] [Chemical Formula 46]

[0279]

[0280] [Example 1] Fabrication of Photoelectric Conversion Element and Evaluation of Current-Voltage Characteristics

[0281] A glass substrate (conductive support 1, manufactured by Solaronix) coated with a fluorine-doped tin oxide (FTO) thin film and subjected to an etching treatment was ultrasonically cleaned with isopropyl alcohol and then subjected to a UV ozone treatment.

[0282] A tin oxide dispersion (electron transport layer coating solution) consisting of 15% tin(IV) oxide in H2O colloidal dispersion (manufactured by Alfa Aesar) and purified water in a volume ratio of 1:3 was applied to the FTO film by spin coating. The film was then heated at 150°C for 30 minutes on a hot plate to form a tin oxide thin film (electron transport layer 2) with a thickness of approximately 40 nm.

[0283] In a glove box under a nitrogen flow, formamidine hydroiodide (1 M, manufactured by Tokyo Chemical Industry Co., Ltd.), lead (II) iodide (1.1 M, manufactured by Tokyo Chemical Industry Co., Ltd.), methylamine hydrobromide (0.2 M, manufactured by Tokyo Chemical Industry Co., Ltd.), and lead (II) bromide (0.2 M, manufactured by Tokyo Chemical Industry Co., Ltd.) were dissolved in a mixed solvent of dimethylformamide and dimethyl sulfoxide at a volume ratio of 4:1. A dimethyl sulfoxide solution of cesium iodide (1.5 M, manufactured by Tokyo Chemical Industry Co., Ltd.) was added to this mixture so that the cesium content reached 5% of the composition ratio, thereby preparing a perovskite precursor solution.

[0284] In a nitrogen-filled glove box, the prepared perovskite precursor solution was dropwise added and spin-coated onto the tin oxide thin film. During the spin coating, 0.3 mL of chlorobenzene was added to form a perovskite precursor film. The film was then heated at 100°C for 1 hour on a hot plate to form a Cs(MAFA)Pb(IBr)3 layer (photoelectric conversion layer 3) with a thickness of approximately 500 nm.

[0285] In a glove box under a nitrogen flow, 4-tert-butylpyridine and lithium bis(trifluoromethanesulfonyl)imide as dopants were dissolved in chlorobenzene. Compound (A-2), the hole transport material obtained in Synthesis Example 1, was dissolved in this chlorobenzene solution to a concentration of 50 mM. The amount of 4-tert-butylpyridine was adjusted to 3 equivalents and the amount of lithium bis(trifluoromethanesulfonyl)imide to 0.5 equivalents relative to Compound (A-2), to prepare a coating solution for a hole transport layer.

[0286] In a glove box under a nitrogen atmosphere, a hole transport layer coating liquid was spin-coated on the Cs(MAFA)Pb(IBr)3 layer (photoelectric conversion layer 3) to form a hole transport layer 4 having a film thickness of about 200 nm.

[0287] On the hole transport layer, vacuum evaporation was used at a vacuum degree of 1×10 -4 Gold was deposited to a thickness of 80 to 100 nm at approximately 100 Pa to form a gold electrode (counter electrode 5 ), thereby producing a photoelectric conversion element.

[0288] The photoelectric conversion element was irradiated with simulated sunlight (AM 1.5, 100 mW / cm 2 ) from the conductive support side using a white light irradiation device (manufactured by Spectrometer Co., Ltd., OTENTO-SUN SH model). 2 ), using a source flow meter (Model 2400 Series Source Meter manufactured by Keithley), the current-voltage characteristics were measured to obtain the photoelectric conversion efficiency. The obtained current-voltage characteristics and photoelectric conversion efficiency are shown in Table 1.

[0289] [Example 2]

[0290] A photoelectric conversion element was prepared in the same manner as in Example 1, except that compound (A-15) was dissolved in the chlorobenzene solution of the dopant to a concentration of 30 mM in place of compound (A-2). The current-voltage characteristics were measured to determine the photoelectric conversion efficiency. The obtained current-voltage characteristics and photoelectric conversion efficiency are shown in Table 1.

[0291] [Example 3]

[0292] A photoelectric conversion element was prepared in the same manner as in Example 1 except that compound (A-28) was used instead of compound (A-2). The current-voltage characteristics and photoelectric conversion efficiency were measured. The obtained current-voltage characteristics and photoelectric conversion efficiency are shown in Table 1.

[0293] [Example 4]

[0294] A photoelectric conversion element was prepared in the same manner as in Example 1 except that compound (A-41) was used instead of compound (A-2), and the current-voltage characteristics were measured to obtain the photoelectric conversion efficiency. The obtained current-voltage characteristics and photoelectric conversion efficiency are shown in Table 1.

[0295] [Example 5]

[0296] A photoelectric conversion element was prepared in the same manner as in Example 1 except that compound (A-67) was used instead of compound (A-2), and the current-voltage characteristics were measured to obtain the photoelectric conversion efficiency. The obtained current-voltage characteristics and photoelectric conversion efficiency are shown in Table 1.

[0297] [Comparative Example 1]

[0298] A photoelectric conversion element was prepared in the same manner as in Example 1, except that Spiro-OMeTAD (manufactured by Sigma-Aldrich Co.), a standard hole transport material represented by the following formula (B-1), was used instead of compound (A-2). The current-voltage characteristics were measured to determine the photoelectric conversion efficiency. The obtained current-voltage characteristics and photoelectric conversion efficiency are shown in Table 1.

[0299] [Chemical Formula 47]

[0300]

[0301] [Table 1]

[0302]

[0303] As can be seen from the results in Table 1, the photoelectric conversion elements using the compounds (A-2), (A-15), (A-28), (A-41) and (A-67) having a fluorenone skeleton of the present invention as hole transport materials show higher photoelectric conversion efficiency than the photoelectric conversion element using the standard hole transport material, namely compound (B-1).

[0304] [Example 6] Fabrication of Photoelectric Conversion Element and Evaluation of Current-Voltage Characteristics

[0305] A glass with a flat ITO film (conductive support 1, manufactured by Geomatec) was ultrasonically cleaned with isopropyl alcohol and then subjected to UV ozone treatment.

[0306] A tin oxide dispersion (electron transport layer coating solution) consisting of tin(IV) oxide, 15% in H2O colloidal dispersion (manufactured by Alfa Aesar) and purified water at a volume ratio of 1:9 was applied to the ITO film by spin coating. This was then heated on a hot plate at 150°C for 30 minutes to form a tin oxide thin film (electron transport layer 2) with a thickness of approximately 20 nm.

[0307] In a glove box under a nitrogen flow, formamidine hydroiodide (1 M, manufactured by Tokyo Chemical Industry Co., Ltd.), lead (II) iodide (1.1 M, manufactured by Tokyo Chemical Industry Co., Ltd.), methylamine hydrobromide (0.2 M, manufactured by Tokyo Chemical Industry Co., Ltd.), and lead (II) bromide (0.2 M, manufactured by Tokyo Chemical Industry Co., Ltd.) were dissolved in a mixed solvent of dimethylformamide and dimethyl sulfoxide at a volume ratio of 4:1. A dimethyl sulfoxide solution of cesium iodide (1.5 M, manufactured by Tokyo Chemical Industry Co., Ltd.) was added to this mixture so that the cesium content was 5% by weight, thereby preparing a perovskite precursor solution.

[0308] In a nitrogen-filled glove box, the prepared perovskite precursor solution was dropwise added and spin-coated onto the tin oxide thin film. During the spin coating, 0.3 mL of chlorobenzene was added to form a perovskite precursor film. The film was then heated at 100°C for 1 hour on a hot plate to form a Cs(MAFA)Pb(IBr)3 layer (photoelectric conversion layer 3) with a thickness of approximately 500 nm.

[0309] In a glove box under a nitrogen flow, 4-tert-butylpyridine and lithium bis(trifluoromethanesulfonyl)imide as dopants were dissolved in chlorobenzene. Compound (A-36), the hole-transporting material obtained in Synthesis Example 19, was dissolved in this chlorobenzene solution to a concentration of 30 mM at 60°C. The amount of 4-tert-butylpyridine was adjusted to 3 equivalents and the amount of lithium bis(trifluoromethanesulfonyl)imide to 0.5 equivalents relative to compound (A-36) to prepare a coating solution for a hole-transport layer.

[0310] In a glove box under a nitrogen atmosphere, a hole transport layer coating solution was spin-coated on the Cs(MAFA)Pb(IBr)3 layer (photoelectric conversion layer 3) to form a hole transport layer 4 having a film thickness of about 200 nm.

[0311] The hole transport layer was deposited by vacuum evaporation at a vacuum degree of 1×10 -4 Gold was deposited in a film of about 80 nm in thickness at about 100 Pa to form a gold electrode (counter electrode 5), thereby producing a photoelectric conversion element.

[0312] The photoelectric conversion element was irradiated with simulated sunlight (AM 1.5, 100 mW / cm 2 ) from the conductive support side using a white light irradiation device (manufactured by Spectrometer Co., Ltd., OTENTO-SUN SH model). 2 ), using a source flow meter (Model 2400 Series Source Meter manufactured by Keithley), the current-voltage characteristics were measured to obtain the initial photoelectric conversion efficiency. The obtained current-voltage characteristics and initial photoelectric conversion efficiency are shown in Table 2.

[0313] After measuring the current-voltage characteristics, the photoelectric conversion element was stored in a desiccator filled with silica gel for 30 days, and the current-voltage characteristics were measured again under pseudo-sunlight irradiation to obtain the photoelectric conversion efficiency after 30 days.

[0314] Table 2 shows the retention rate (%) calculated from the obtained initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 30 days, that is, the photoelectric conversion efficiency over time, using the following formula (a-1).

[0315] [Number 1]

[0316]

[0317] [Example 7]

[0318] A photoelectric conversion element was prepared in the same manner as in Example 6, except that compound (A-49) was dissolved in the chlorobenzene solution of the dopant at 90°C to a concentration of 30 mM in place of compound (A-36). The initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 30 days were obtained in the same manner as in Example 6. The initial photoelectric conversion efficiency is shown in Table 2. The retention rate (%) calculated from the photoelectric conversion efficiency after 30 days using the above formula (a-1) is also shown in Table 2.

[0319] [Example 8]

[0320] A photoelectric conversion element was prepared in the same manner as in Example 6, except that compound (A-79) was dissolved in the chlorobenzene solution of the dopant at 90°C to a concentration of 30 mM in place of compound (A-36). The initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 30 days were obtained in the same manner as in Example 6. The initial photoelectric conversion efficiency is shown in Table 2. The retention rate (%) calculated from the photoelectric conversion efficiency after 30 days using the above formula (a-1) is also shown in Table 2.

[0321] [Example 9]

[0322] A photoelectric conversion element was prepared in the same manner as in Example 6, except that compound (A-96) was dissolved in the above-mentioned dopant chlorobenzene solution to a concentration of 40 mM at room temperature instead of compound (A-36). The initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 30 days were obtained in the same manner as in Example 6. The initial photoelectric conversion efficiency is shown in Table 2. The retention rate (%) calculated using the photoelectric conversion efficiency after 30 days using the above formula (a-1) is also shown in Table 2.

[0323] [Example 10]

[0324] A photoelectric conversion element was prepared in the same manner as in Example 6, except that compound (A-155) was dissolved in the above-mentioned dopant chlorobenzene solution to a concentration of 50 mM at room temperature instead of compound (A-36). The initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 30 days were obtained in the same manner as in Example 6. The initial photoelectric conversion efficiency is shown in Table 2. The retention rate (%) calculated using the photoelectric conversion efficiency after 30 days using the above formula (a-1) is also shown in Table 2.

[0325] [Example 11]

[0326] A photoelectric conversion element was prepared in the same manner as in Example 6, except that compound (A-83) was dissolved in the chlorobenzene solution of the dopant at room temperature to a concentration of 50 mM in place of compound (A-36). The initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 30 days were obtained in the same manner as in Example 6. The initial photoelectric conversion efficiency is shown in Table 2. The retention rate (%) calculated using the photoelectric conversion efficiency after 30 days using the above formula (a-1) is also shown in Table 2.

[0327] [Example 12]

[0328] A photoelectric conversion element was prepared in the same manner as in Example 6, except that compound (A-11) was dissolved in the chlorobenzene solution of the dopant at 90°C to a concentration of 20 mM in place of compound (A-36). The initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 30 days were obtained in the same manner as in Example 6. The initial photoelectric conversion efficiency is shown in Table 2. The retention rate (%) calculated using the photoelectric conversion efficiency after 30 days using formula (a-1) is also shown in Table 2.

[0329] [Comparative Example 2]

[0330] A photoelectric conversion element was prepared in the same manner as in Example 6, except that Spiro-OMeTAD (manufactured by Sigma-Aldrich), a standard hole transport material represented by the above formula (B-1), was dissolved in the above dopant chlorobenzene solution to a 50 mM concentration at room temperature instead of compound (A-36). The initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 30 days were obtained in the same manner as in Example 6. The initial photoelectric conversion efficiency is shown in Table 2. The retention rate (%) calculated using the photoelectric conversion efficiency after 30 days using formula (a-1) is also shown in Table 2.

[0331] [Table 2]

[0332]

[0333] As can be seen from the results in Table 2, the photoelectric conversion elements using the compounds (A-36), (A-37), (A-79), (A-96), (A-155) and (A-83) having a fluorenone skeleton of the present invention as hole transport materials show higher photoelectric conversion efficiency than the photoelectric conversion element using the standard hole transport material, namely compound (B-1).

[0334] As can be seen from the results in Table 2, the photoelectric conversion elements using the compounds (A-36), (A-37), (A-79), (A-96), (A-155), (A-83) and (A-11) having a fluorenone skeleton of the present invention as hole transport materials show better storage durability than the photoelectric conversion element using the standard hole transport material, namely compound (B-1).

[0335] The photoelectric conversion element using the hole transport material of the present invention exhibits good photoelectric conversion efficiency and can be used as a solar cell that efficiently converts sunlight energy into electrical energy to provide clean energy. It can also be expanded to other organic ELs, image sensors, etc.

[0336] (Explanation of Reference Numerals)

[0337] 1: Conductive support

[0338] 2: Electron transport layer

[0339] 3: Photoelectric conversion layer

[0340] 4: Hole transport layer

[0341] 5: Counter electrode

Claims

1. A compound represented by the following general formula (1), [Chemical Formula 1] Where R 1 、R 2 、R 4 、R 7 、R 9 、R 10 、R 11 、R 12 、R 14 、R 17 、R 19 and R 20 represents a hydrogen atom, R 5 、R 6 、R 15 and R 16 represents a hydrogen atom, or R 5 and R 6 , and R 15 and R 16 are bonded to each other via a single bond to form a ring, When R 5 、R 6 、R 15 and R 16 When it is a hydrogen atom, R 3 、R 8 、R 13 and R 18 is an alkoxy group having 1 to 20 carbon atoms, When R 5 and R 6 , and R 15 and R 16 When they are bonded to each other via a single bond to form a ring, R 3 、R 8 、R 13 and R 18 is a diphenylamino group substituted with an alkoxy group having 1 to 18 carbon atoms, X 1 and X 2 represents a divalent group represented by the following general formula (2), Y represents CR 21 R 22 , R 21 and R 22 Each independently represents an ethoxycarbonyl group, [Chemical Formula 2] Where R 23 ~R 28 each independently represents a hydrogen atom, R 23 and R 24 、R 25 and R 26 and R 27 and R 28 can bond to each other to form a ring, Z represents a sulfur atom, m and n represent integers of 0 to 2, and both m and n are not 0 at the same time.

2. A hole transport material formed from the compound according to claim 1.

3. A photoelectric conversion element using the hole transport material according to claim 2.

Images