Compounds and photoelectric elements

Abstract

The objective is to provide a photoelectric conversion element that exhibits excellent photoelectric conversion characteristics. [Solution] The photoelectric conversion element is characterized by using a compound shown in the following general formula (I) as a passivation film on the perovskite layer. In general formula (I), Z is a substituent having an amine or a salt thereof, and may be bonded to the aromatic ring by a single bond or via a divalent linking group, and may be present alone or in multiples. JPEG2026114493000031.jpg3859

Description

[Technical Field]

[0001] This invention relates to compounds and photoelectric conversion elements. [Background technology]

[0002] In recent years, solar power generation has attracted attention as a clean energy source, and the development of solar cells is progressing. As one example, solar cells using perovskite materials as the light-absorbing layer are rapidly gaining attention as a next-generation solar cell that can be manufactured at low cost. For example, Non-Patent Document 1 reports on a solution-type solar cell using perovskite materials as the light-absorbing layer. Furthermore, Non-Patent Document 2 reports that solid-state perovskite solar cells exhibit high efficiency.

[0003] In perovskite solar cells, passivation using quaternary ammonium salts such as 2-phenylethylamine bromide has been reported to fill defects in the perovskite layer. However, passivation is difficult to control; even a slightly larger amount can result in an insulating film, leading to a decrease in performance, while a smaller amount fails to fill defects, thus not leading to performance improvement. Furthermore, while many passivation films have been formed by spin-coating in the laboratory, and relatively easy to deposit on small areas, uniformly performing passivation on the perovskite layer of large-area devices has been extremely difficult. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Journal of the American Chemical Society, 2009, 131, 6050-6051. [Non-Patent Document 2] Science, 2012, 388, 643-647. [Overview of the project]

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide a passivation compound having excellent performance and a photoelectric conversion device using this compound.

Means for Solving the Problems

[0006] To achieve the above object, an aspect of the present invention is a compound and a photoelectric conversion device. (1) The compound is a compound in which a plurality of aromatic hydrocarbon rings or heterocycles are condensed, each ring is polarized negatively or positively, and has an amine or its salt as a substituent. (2) The compound according to (1) is characterized in that it is represented by the following general formula (I).

Chemical formula

Chemical formula

[0007] According to the present invention, it is possible to provide a passivation compound that exhibits excellent photoelectric conversion characteristics. [Brief explanation of the drawing]

[0008] [Figure 1] This is a cross-sectional view showing an example of a photoelectric conversion element (forward structure) of an embodiment. [Figure 2] This is a cross-sectional view showing an example of a photoelectric conversion element (inverted structure) of an embodiment. [Figure 3] This is a conceptual diagram of passivation when a substituent is introduced to the five-membered ring side, which is an example of a compound in the embodiment. [Figure 4] This is a conceptual diagram of passivation when a substituent is introduced to the 7-membered ring side, which is an example of a compound in the embodiment. [Figure 5] This is the 1H-NMR chart of synthesis example 3 of the embodiment. [Figure 6] This is the 13C-NMR chart for synthesis example 3 of the embodiment. [Figure 7] This is the 1H-NMR chart of the compound from Synthesis Example 6 of the embodiment. [Figure 8] This is the 13C-NMR chart of the compound from Synthesis Example 6 of the embodiment. [Figure 9] This is a plan view showing the manufacturing process of a solar cell module according to an embodiment. [Figure 10] This is a plan view showing the manufacturing process of a solar cell module according to an embodiment. [Figure 11] This is a plan view showing the manufacturing process of a solar cell module according to an embodiment. [Figure 12] This is a cross-sectional view along the line A-A' in Figure 11 of the embodiment. [Modes for carrying out the invention]

[0009] The photoelectric conversion element of the present invention may include a compound represented by the following general formula (I) as a passivation layer of the perovskite layer. [ka]

[0010] Specific examples of general formula (I) in the present invention include the compounds shown below as A-1 to A-29. In the compounds shown as A-1 to A-29, Z represents an amine or a salt of an amine, and the amine or salt of an amine may have substituents. Specifically, examples include alkyl groups such as methyl, ethyl, and isopropyl groups, aryl groups such as phenyl and 1-naphthyl groups, and aralkyl groups such as benzyl and phenylethyl groups, and may have up to three substituents. R1 can be a hydrogen atom, an alkyl group such as methyl, ethyl, and isopropyl groups, aryl groups such as phenyl and 1-naphthyl groups, aralkyl groups such as benzyl and phenylethyl groups, alkoxy groups such as methoxy and ethoxy groups, and may have multiple halogen atoms. In the case of salts, they must contain anions, and specific examples of such anions include halogen anions such as fluoride ions, chloride ions, bromide ions, and iodide ions, as well as boron trifluoroanions, hexafluorophosphate anions, tetraboron fluoride anions, bis(trifluoromethanesulfonyl)imide anions, and bis(fluorosulfonyl)imide anions.

[0011] [ka] [ka]

[0012] In the present invention, a film made of azulene compound salts represented by A-1 to A-29 is formed on a perovskite layer (referred to as a surface treatment step). The azulene compound salts represented in the present invention are preferably dissolved in one or more solvents. Examples of such solvents include alcohols such as isopropanol (2-propanol), ethanol (EtOH), methanol (MeOH), and butanol; nitriles such as acetonitrile and propionitrile; and aromatic solvents such as toluene, chlorobenzene, and 1,2-dichlorobenzene. For example, one type of solvent may be used alone, or two or more types may be used in combination.

[0013] The surface treatment step is carried out by applying a solution containing the azulene compound salt onto the formed perovskite layer and drying it. The method of applying the solution is not particularly limited and can be appropriately selected depending on the purpose, and examples include immersion method, spin coating method, spray method, dip method, roller method, and air knife method. In the surface treatment step, a heat treatment may be performed after the application, and if heating is performed, the heating temperature is preferably, for example, 50 to 200°C, and more preferably 70 to 180°C. The heating time is preferably, for example, 1 to 150 minutes, and more preferably 5 to 60 minutes. The film thickness to which the solution is applied is not particularly limited.

[0014] [Photoelectric conversion element] The configuration and components of the photoelectric conversion element of the present invention will be described in more detail below with examples. However, the photoelectric conversion element of the present invention is not limited to the following examples. In the following, the case in which the photoelectric conversion element of the present invention is a solar cell will be mainly described.

[0015] Figures 1 and 2 show an example of the configuration of the photoelectric conversion element of the present invention. For the sake of explanation, Figures 1 and 2 are schematic representations with appropriate omissions and exaggerations. As shown in the figures, the photoelectric conversion element of the present invention is a perovskite solar cell, with Figure 1 showing the forward structure and Figure 2 showing the reverse structure.

[0016] [Supports 11, 21] The supports 11 and 21 are not particularly limited, and for example, substrates usable in photoelectric conversion elements such as general solar cells may be used as appropriate. Examples of such substrates include glass, plastic plates, plastic films, and inorganic crystals. Furthermore, substrates on which at least one type of film, such as a metal film, semiconductor film, conductive film, and insulating film, is formed on part or all of the surface of these substrates can also be suitably used as supports 11 and 21. The size, thickness, etc., of the supports 11 and 21 are not particularly limited, and for example, they may be the same as or similar to those of general photoelectric conversion elements such as general solar cells.

[0017] [First electrodes 12, 22] The first electrodes 12 and 22 may be formed directly on the supports 11 and 21, for example. The first electrodes 12 and 22 may also be transparent electrodes formed from a conductor, for example. The transparent electrodes are not particularly limited, but examples include tin-doped indium oxide (ITO) films, impurity-doped indium oxide (In2O3) films, impurity-doped zinc oxide (ZnO) films, fluorine-doped tin dioxide (FTO) films, laminated films formed by laminating two or more of these, gold, silver, copper, aluminum, tungsten, titanium, chromium, nickel, and cobalt. These may be used individually or as a mixture of two or more, and may be single layers or laminated. Furthermore, these films may function as, for example, diffusion barrier layers. The thickness of the first electrodes 12 and 22 is not particularly limited, but it is preferable to adjust it so that the sheet resistance is 5 to 15 Ω / □ (per unit area). The method for forming the first electrodes 12 and 22 is not particularly limited, but can be obtained by known film formation methods depending on the material to be formed. The shape of the first electrodes 12 and 22 is also not particularly limited, but can be formed in the form of a film or in a grid-like shape such as a mesh. The method for forming the first electrodes 12 and 22 on the supports 11 and 21 is not particularly limited, but can be a known method, for example, vacuum deposition such as vacuum evaporation or sputtering is preferred. The first electrodes 12 and 22 may also be patterned. The patterning method is not particularly limited, but can be, for example, immersion in a laser or etching solution, or patterning using a mask during vacuum deposition, and any of these methods can be used in the present invention. In addition, the first electrodes 12 and 22 may be used in combination with metal wiring to reduce their electrical resistance. The material of the metal wiring (metal lead wire) is not particularly limited, but can be, for example, aluminum, copper, silver, gold, platinum, nickel, etc. The aforementioned metal lead wires can be formed on a first substrate by, for example, vapor deposition, sputtering, or crimping, and then used in combination by providing a layer of ITO or FTO on top of it, or by providing it on top of ITO or FTO.

[0018] [Electron transport layer 13, 23] There are no particular restrictions on the materials used for the electron transport layers 13 and 23, and they can be appropriately selected according to the purpose, but semiconductor materials are preferred. There are no particular restrictions on the semiconductor material, but widely known materials can be used, for example, elemental semiconductors, compound semiconductors, organic n-type semiconductors, etc., and among these, metal oxide semiconductors are the most suitable. The aforementioned compound semiconductors are not particularly limited, but examples include metal chalcogenides, specifically oxides of titanium, tin, zinc, iron, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium, tantalum, etc.; sulfides of cadmium, zinc, lead, silver, antimony, bismuth, etc.; selenides of cadmium, lead, etc.; tellurides of cadmium, etc. Other compound semiconductors include phosphides of zinc, gallium, indium, cadmium, etc., gallium arsenide, copper-indium selenide, copper-indium sulfide, etc. The organic n-type semiconductor is not particularly limited, but examples include perylenetetracarboxylic anhydride, perylenetetracarboxydiimide compounds, naphthalenediimide-bithiophene copolymer, benzobisimidazobenzophenanthroline polymer, C 60 , C 70 PCBM([6,6]-phenyl-C 61 Examples of materials include frehlan compounds such as methyl butyrate, carbonyl bridge-bithiazole compounds, ALq3 (tris(8-quinolinolato)aluminum), triphenylene bipyridyl compounds, silole compounds, and oxadiazole compounds. In the present invention, among the above materials used for the electron transport layer 15, organic n-type semiconductors are particularly preferred. Furthermore, there are no restrictions on the crystal type of these semiconductor materials, and they can be appropriately selected according to the purpose; they may be single crystals, polycrystalline, or amorphous. Also, there are no particular restrictions on the film thickness of the electron transport layer 15, and it can be appropriately selected according to the purpose, but 5 nm to 1000 nm is preferred, and 10 nm to 700 nm is more preferred.

[0019] The method for forming the electron transport layers 13 and 23 is not particularly limited and can be appropriately selected according to the purpose. For example, methods for forming a thin film in a vacuum (vacuum film forming method), wet film forming methods, etc. can be mentioned. Examples of the vacuum film forming method include sputtering method, pulsed laser deposition method (PLD method), ion beam sputtering method, ion assist method, ion plating method, vacuum evaporation method, atomic layer deposition method (ALD method), chemical vapor deposition method (CVD method), etc. Examples of the wet film forming method include a method of applying a solvent in which an electron transport material is dissolved to form a film, and in the case of an oxide semiconductor, a sol-gel method. The sol-gel method is a method of producing a gel from a solution through chemical reactions such as hydrolysis, polymerization, and condensation, and then promoting densification by heat treatment. When the sol-gel method is used, the method for applying the sol solution is not particularly limited and can be appropriately selected according to the purpose. For example, dip method, spray method, wire bar method, spin coating method, roller coating method, blade coating method, gravure coating method, and as wet printing methods, relief printing, offset, gravure, intaglio, rubber plate, screen printing, etc. can be mentioned. Also, the temperature during the heat treatment after applying the sol solution is preferably 80 °C or higher, more preferably 100 °C or higher.

[0020] [Photoelectric conversion layers 14, 24] The photoelectric conversion layers 14 and 24 are not particularly limited and may be the same as the photoelectric conversion layers used in general photoelectric conversion elements such as solar cells. The photoelectric conversion layers 14 and 24 contain a perovskite compound. The perovskite compound may be, for example, a compound represented by the following chemical formula (I). X 1 α Y 1 β Z 1 γ ...(I)

[0021] In the chemical formula (I), the ratio of α:β:γ is 3:1:1, and β and γ represent integers greater than 1. X 1 is a halogen ion, Y 1 is an organic compound having an amino group, Z 1represents a metal ion. The perovskite layer is preferably positioned adjacent to the electron transport layer. Note that the α:β:γ ratio does not necessarily have to be 3:1:1; for example, 3:1.05:0.95. Also, X 1 There are no particular restrictions on the choice of halogen ions, and they can be selected appropriately depending on the purpose. Examples include halogen ions such as chlorine, bromine, and iodine. These may be used individually or in combination of two or more. 1 Examples include alkylamine compound ions (organic compounds having an amino group) such as methylamine, ethylamine, n-butylamine, and formamidine, as well as alkali metal ions such as cesium, potassium, and rubidium, which are not limited to organic compounds. Alkylamine compound ions and alkali metal ions may be used individually or in combination of two or more. Furthermore, organic (alkylamine compound ions) and inorganic (alkali metal ions) can be used in combination; for example, cesium ions and formamidine may be used together. 1 There are no particular restrictions on the metals used, and they can be appropriately selected according to the purpose. Examples include metals such as lead, indium, antimony, tin, copper, and bismuth. These may be used individually or in combination of two or more. Lead is particularly preferred, and among these, the combination of lead and tin is especially preferred. Furthermore, the perovskite layer preferably exhibits a layered perovskite structure in which layers made of metal halides and layers in which organic cation molecules are arranged are alternately stacked. The perovskite layer may also contain alkali metals. The inclusion of at least alkali metals in the perovskite layer is advantageous in that it increases the output. Examples of alkali metals include cesium, rubidium, and potassium. Among these, cesium is preferred.

[0022] As described above, the photoelectric conversion layers 14 and 24 may be perovskite layers formed from perovskite compounds. There are no particular restrictions on the method for forming such perovskite layers, and a suitable method can be selected depending on the purpose. For example, a method may be used in which a solution of metal halide and alkylamine halide is dissolved or dispersed is applied and then dried.

[0023] Furthermore, methods for forming the perovskite layer include, for example, a two-step deposition method in which a solution containing dissolved or dispersed metal halides is applied, dried, and then immersed in a solution containing dissolved alkylamine halides to form the perovskite compound. Other methods include applying a solution containing dissolved or dispersed metal halides and alkylamine halides while adding a poor solvent (solvent with low solubility) for the perovskite compound to precipitate crystals. In addition, a method of depositing metal halides in a gas filled with methylamine or the like is also possible. Moreover, a method of applying a solution containing dissolved or dispersed metal halides and alkylamine halides while adding a poor solvent for the perovskite compound to precipitate crystals is particularly preferred. There are no particular restrictions on the method of applying these solutions, and they can be appropriately selected according to the purpose, and examples include immersion method, spin coating method, spray method, dip method, roller method, and air knife method. Furthermore, the method of applying the solution may also be deposition in a supercritical fluid using carbon dioxide or the like. Examples of poor solvents that can be used in the method of precipitating crystals by adding the poor solvents described above include hydrocarbons such as n-hexane and n-octane, alcohols such as methanol, ethanol, and 2-propanol, ethers such as diethyl ether and diisopropyl ether, ketones such as acetone and methyl isobutyl ketone, esters such as ethyl acetate, isobutyl acetate, and γ-butyrolactone, nitriles such as acetonitrile and 3-methoxypropionitrile, aromatic hydrocarbon compounds such as benzene, toluene, and chlorobenzene, halogenated solvents such as dichloromethane and chloroform, and fluorinated solvents such as chlorofluorocarbons, hydrochlorofluorocarbons, and hydrofluorocarbons.

[0024] The method for forming the perovskite layer may further include, for example, a step aimed at removing the solvent after the perovskite layer has been formed (solvent removal step), or a step aimed at arranging perovskite crystals (crystal arrangement step). The solvent removal step and the crystal arrangement step may be carried out by, for example, blowing dry air, heating with a hot plate or oven, or vacuum drying. In the solvent removal step and the crystal arrangement step, the heating temperature is preferably, for example, 50 to 200°C, and more preferably 70 to 180°C. In the solvent removal step and the crystal arrangement step, the heating time is preferably, for example, 1 to 150 minutes, and more preferably 5 to 60 minutes. Furthermore, the thickness of the photoelectric conversion layers 14 and 24 is not particularly limited, but from the viewpoint of further suppressing performance degradation due to defects and peeling, for example, 50 to 1500 nm is preferred, and 200 to 1000 nm is more preferred.

[0025] In this invention, a film containing a two-dimensional perovskite compound is formed on a layer made of a three-dimensional perovskite compound. The two-dimensional perovskite can be represented by chemical formula (II). X 2 α2 Y 2 β2 Z 2 γ2 ...(II) For example, Japanese Patent Publication No. 6714412 describes a material for forming two-dimensional perovskites. Thus, two-dimensional perovskite compounds are known. Two-dimensional perovskite compounds are perovskite compounds having a two-dimensional crystalline structure. For example, a two-dimensional perovskite compound has a layered structure in which inorganic layers, each consisting of an inorganic skeleton corresponding to the octahedral portion of a perovskite-type structure arranged in two dimensions, and organic layers consisting of oriented organic cations are alternately stacked.

[0026] In the above chemical formula (II), X 2 is a halogen ion, Y 2 Z is a metal ion. 2α represents an organic compound having an amino group or an alkali metal ion. α2, β2, and γ2 are the composition ratios of the two-dimensional perovskite compound. In the above chemical formula (II), an example of the α:β:γ ratio is 4:2:1. The α:β:γ ratio does not necessarily have to be an integer, for example, 4:1.8:1.2. Also, 0.5γ2≦α2≦8γ2 is preferred, 1γ2≦α2≦6γ2 is preferred, and 3γ2≦α2≦5γ2 is also acceptable. 0.5γ2≦β2≦5γ2 is preferred, γ2≦β2≦4γ2 is preferred, and 1.5γ2≦β2≦2γ2 is also acceptable. 2 X 1 It is the same as Y 2 Y 1 It is similar to that. Z 2 R 2 -The one indicated by A is preferred and more preferred, R 2 This is represented by -NH2. Here, R 2 This represents a linear or segmented C4-C8 alkyl group, a C6-C8 aryl group which may be substituted with a linear or segmented C1-C3 alkyl group, or a C7-C12 aralkyl group. R 2 Specific examples of these include alkyl groups with four or more carbon atoms, such as n-butyl, n-hexyl, n-dodecyl, and 2-ethylhexyl groups; aryl groups, such as phenyl, 4-methoxyphenyl, 3-chlorophenyl, and 1-naphthyl groups; aralkyl groups, such as benzyl, 2-phenylethyl, 2-thiophenemethyl, and 3-thiophenemethyl groups; and heterocycles, such as 2-furyl and 2-pyridyl groups. A represents an ammonium cation. Furthermore, the method for forming two-dimensional perovskite compounds can be the same as the method for forming three-dimensional perovskite compounds.

[0027] It is preferable to obtain a perovskite-containing film by coating a photoelectric conversion layer with a saturated solution of a precursor of a two-dimensional perovskite compound. In this step, any solvent used in the fabrication of the photoelectric conversion layer may be used as the solvent. This film may also function as a passivation layer.

[0028] [Hole transport layers 15, 25] In the sequential structure shown in Figure 1, the hole transport layer 15 is a layer that has the function of transporting electric charge, and can be made of a conductor, semiconductor, organic hole transport material, etc. The organic hole transport material receives holes from the photoelectric conversion layer 14 and functions as a hole transport material that transports holes. The conductor and semiconductor can be inorganic hole transport materials or organic hole transport materials. Examples of inorganic hole transport materials include 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, MoO3, and Cr2O. Among these, from the viewpoint of receiving only holes more efficiently and obtaining higher hole mobility, semiconductors containing monovalent copper are preferred, and NiO, CuI, or CuSCN are more preferred. Examples of the aforementioned 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. Among these, triphenylamine derivatives and fluorene derivatives are preferred from the viewpoint of more efficiently receiving only holes and obtaining higher hole mobility, and PTAA and Spiro-OMeTAD are more preferred.

[0029] Furthermore, the aforementioned organic hole transport materials are further improved in order to enhance their hole transport properties, for example, by using lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), silver bis(trifluoromethylsulfonyl)imide, zinc bis(trifluoromethylsulfonyl)imide, ammonium bis(trifluoromethanesulfonyl)imide, lithium bis(nonafluorobutanesulfonyl)imide, sodium bis(nonafluorobutanesulfonyl)imide, lithium nonafluoro-N-[(trifluoromethane)sulfonyl]butanesulfonylamide, potassium nonafluoro The material may also contain oxidizing agents such as oro-N-[(trifluoromethane)sulfonyl]butanesulfonylamide, nonafluoro-N-[(trifluoromethane)sulfonyl]butanesulfonylamide, lithium N,N-hexafluoro-1,3-disulfonylimide, sodium N,N-hexafluoro-1,3-disulfonylimide, trifluoromethylsulfonyloxysilver, NOSbF6, SbCl5, SbF5, and tris(2-(1H-pyrazole-1-yl)-4-tert-butylpyridine)cobalt(III)tri[bis(trifluoromethane)sulfonimide]. Furthermore, the hole transport layers 15 and 25 may also contain basic compounds such as tert-butylpyridine (TBP), 2-picoline, and 2,6-lutidine. The content of the oxidizing agent and basic compounds can be, for example, amounts commonly used conventionally. From the viewpoint of more efficiently receiving only holes and obtaining higher hole mobility, the thickness of the hole transport layer 15 is preferably 1 to 500 nm, and more preferably 2 to 300 nm. The method for forming the hole transport layer 15 is preferably carried out under a dry atmosphere. For example, it is preferable to coat (spin coat, etc.) a solution containing an organic hole transport material onto a perovskite layer (light absorption layer) under a dry atmosphere and heat it at 30 to 180°C, particularly 100 to 150°C.

[0030] Furthermore, as the hole transport layer 25 in the inverted structure shown in Figure 2, it is also possible to use, for example, a hole transport compound that forms a monolayer (hereinafter also referred to as "monolayer hole transport compound"). The monolayer hole transport compound preferably has an anchor that chemically bonds with a transparent electrode such as ITO in the inverted structure. Examples of such anchors include a phosphonic acid group (-P=O(OH)2), a carboxyl group (-COOH), a sulfo group (-SO3H), a boronic acid group (-B(OH)2), a trihalogenated silyl group (-SiX3, where X is a halogen atom), or a trialkoxysilyl group (-Si(OR)3, where R is an alkyl group). Among these, the phosphonic acid group, trihalogenated silyl group, and trialkoxysilyl group are particularly preferred.

[0031] The method for forming the hole transport layer 25 using the monomolecule hole transport material is not particularly limited, but for example, the hole transport layer 25 can be formed by adsorbing the monomolecule hole transport compound onto the first electrode 22 to form a monomolecule layer. The method for adsorbing the monomolecule hole transport compound onto the first electrode 22 to form a monomolecule layer is not particularly limited, but for example, the monomolecule hole transport compound can be dissolved in a solvent and brought into contact with the first electrode 22 to form a bond. The bond between the monomolecule hole transport compound and the first electrode 22 is not particularly limited and may be a physical bond or a chemical bond. The type of bond is also not particularly limited and may be any of the following: hydrogen bond, ester bond, chelate bond, etc. The solvent for dissolving the monomolecule hole transport compound is also not particularly limited and may be either water and an organic solvent, or both. More specifically, examples of the aforementioned solvents include water, alcohols such as methanol, ethanol, and 2-propanol; ethers such as diethyl ether and diisopropyl ether; ketones such as acetone and methyl isobutyl ketone; esters such as ethyl acetate, isobutyl acetate, and γ-butyrolactone; heterocyclic compounds such as tetrahydrofuran and thiophene; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; sulfoxides such as dimethyl sulfoxide; sulfones such as diethyl sulfone and sulfolane; nitriles such as acetonitrile and 3-methoxypropionitrile; aromatic compounds such as benzene, toluene, and chlorobenzene; halogenated solvents such as dichloromethane and chloroform; and fluorinated solvents such as chlorofluorocarbon, hydrochlorofluorocarbon, and hydrofluorocarbon. These solvents may be used individually or in mixtures of two or more.

[0032] The specific method for adsorbing the monomolecule hole transport compound onto the first electrode 22 to form a monolayer is not particularly limited, but known methods such as dipping, spraying, spin coating, and bar coating can be used. The temperature during adsorption is not particularly limited, but -20°C to 100°C is preferred, and 0°C to 50°C is more preferred. The adsorption time is also not particularly limited, but for example, 1 second to 48 hours is preferred, and 10 seconds to 1 hour is more preferred. After the adsorption treatment, washing may or may not be performed. The washing method is also not particularly limited, but for example, a known method may be used as appropriate. After the adsorption treatment or washing, heat treatment may or may not be performed. The temperature for the heat treatment is preferably 50°C to 150°C, and 70°C to 120°C is more preferred. The heat treatment time is preferably 1 second to 48 hours, and 10 seconds to 1 hour is more preferred. This heat treatment may be performed, for example, in the atmosphere or in a vacuum.

[0033] When adsorbing the monomolecule hole transport compound onto the first electrode 22, a co-adsorbent may be used in combination. The co-adsorbent can be added when the monomolecule hole transport compound alone cannot completely coat the electrode surface or to inhibit the interaction between the monomolecule hole transport compounds. Specific examples of the co-adsorbent include phosphonic acid compounds such as n-butylphosphonic acid, n-hexylphosphonic acid, n-decylphosphonic acid, n-octadecylphosphonic acid, 2-ethylhexylphosphonic acid, methoxymethylphosphonic acid, 3-acryloyloxypropylphosphonic acid, 11-hydroxyundecylphosphonic acid, 1H,1H,2H,2H-perfluorophosphonic acid, 3-aminopropylphosphonic acid, and 4-phosphonobutyric acid, as well as acetic acid, propionic acid, isobutyric acid, nonanoic acid, fluoroacetic acid, α-chloropropionic acid, glyoxylic acid, and chenodeoxycholic acid. These can be used individually or in combination of two or more types.

[0034] The method for adsorbing the co-adsorbent onto the first electrode 22 is not particularly limited, but, similar to the monomolar hole transport compound, it is preferable to dissolve it in a solvent before adsorption. The solvent is also not particularly limited, but may be the same as the solvents exemplified above for the monomolar hole transport compound. Furthermore, the co-adsorbent may be adsorbed by first adsorbing the monomolar hole transport compound onto the substrate and then immersing the first electrode 22 in a solvent in which the co-adsorbent is dissolved, or it may be used after mixing and dissolving it together with the monomolar hole transport compound in an organic solvent.

[0035] [Second electrodes 16, 26] The second electrode 16 is a layer that has the function of extracting holes from the photoelectric conversion layer 14 via the hole transport layer 15. The second electrode 16 also functions as, for example, a cathode (positive electrode). The second electrode 26 is a layer that has the function of extracting electrons from the photoelectric conversion layer 24 via the electron transport layer 23. The second electrode 26 also functions as, for example, an anode (negative electrode).

[0036] The second electrode 16 may be formed directly on the hole transport layer 15, and the second electrode 26 may be formed directly on the electron transport layer 23. Furthermore, the material of the second electrodes 16 and 26 is not particularly limited, and for example, the same material as that of the first electrodes 12 and 22 can be used. The shape, structure, and size of the second electrodes 16 and 26 are not particularly limited and can be appropriately selected according to the purpose. Examples of materials for the second electrodes 16 and 26 include metals, carbon compounds, conductive metal oxides, and conductive polymers.

[0037] Examples of the metals include platinum, gold, silver, copper, and aluminum, and examples of the carbon compounds include graphite, fullerene, carbon nanotubes, and graphene. Examples of the conductive metal oxides include ITO, FTO, and ATO. Examples of the conductive polymers include polythiophene and polyaniline. Furthermore, the materials used to form the second electrodes 16 and 26 may be used individually, or two or more may be used in combination (mixed) or laminated. The second electrodes 16 and 26 can be formed by methods such as coating, lamination, vacuum deposition, sputtering, CVD, and bonding.

[0038] Furthermore, in the photoelectric conversion element of the present invention, it is preferable that at least one of the first electrodes 12, 22 and the second electrodes 16, 26 is substantially transparent. When using the photoelectric conversion element of the present invention, it is preferable to make the electrodes transparent and allow incident light to enter from the electrode side. In this case, it is preferable to use a light-reflecting material for the back electrode (the electrode opposite to the transparent electrode, for example, the second electrode), and metals, glass with a conductive oxide deposited on it, plastics, and thin metal films are preferably used. Providing an anti-reflective layer on the electrode on the incident light side is also an effective means.

[0039] [Sealed] The photoelectric conversion element of the present invention (e.g., a solar cell) is preferably sealed to protect the device (the photoelectric conversion element of the present invention) from water and oxygen. The sealing structure is not particularly limited, but may be the same as that of a general photoelectric conversion element (e.g., a solar cell). Specifically, for example, the sealing material may be applied only to the outer periphery of the photoelectric conversion element of the present invention and covered with glass or film, the sealing material may be applied to the entire surface of the photoelectric conversion element of the present invention and covered with glass or film, or the sealing material may be applied to the entire surface of the photoelectric conversion element of the present invention alone.

[0040] There are no particular restrictions on the material of the sealing member, and it can be appropriately selected according to the purpose. For example, epoxy resin or acrylic resin is preferable and cured, but it is also acceptable if it is not cured or if only a part of it is cured.

[0041] The epoxy resin is not particularly limited, but examples include water-dispersible, solvent-free, solid, heat-curing, curing agent-mixed, and UV-curing types. Among these, the heat-curing and UV-curing types are preferred, and the UV-curing type is more preferred. Even with the UV-curing type, heating is possible, and it is preferable to heat even after UV curing. Specific examples of epoxy resins include bisphenol A type, bisphenol F type, novolac type, cyclic aliphatic type, long-chain aliphatic type, glycidylamine type, glycidyl ether type, and glycidyl ester type. These may be used individually or in combination of two or more. It is also preferable to mix the epoxy resin with a curing agent and various additives as needed. Existing epoxy resin compositions can be used in the present invention. Among these, epoxy resin compositions developed and commercially available for solar cells and organic EL elements can be used particularly effectively in the present invention. Examples of commercially available epoxy resin compositions include TB3118, TB3114, TB3124, TB3125F (manufactured by ThreeBond Corporation), WorldRock5910, WorldRock5920, WorldRock8723 (manufactured by Kyōritsu Chemical Industry Co., Ltd.), WB90US(P), and WB90US-HV (manufactured by Moresco).

[0042] The acrylic resin is not particularly limited, but for example, those developed and commercially available for solar cells and organic EL elements can be effectively used. Examples of commercially available acrylic resin compositions include TB3035B and TB3035C (manufactured by ThreeBond Corporation).

[0043] There are no particular restrictions on the curing agent, and it can be appropriately selected depending on the purpose, but examples include amine-based, acid anhydride-based, polyamide-based, and other curing agents. Examples of amine-based curing agents include aliphatic polyamines such as diethylenetriamine and triethylenetetramine, and aromatic polyamines such as metaphenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone. Examples of acid anhydride-based curing agents include phthalic anhydride, tetra and hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, pyromellitic anhydride, hetic anhydride, and dodecenyl succinic anhydride. Examples of other curing agents include imidazoles and polymer captans. These may be used alone or in combination of two or more.

[0044] There are no particular restrictions on the aforementioned additives, and they can be appropriately selected according to the purpose. Examples include fillers, gap fillers, polymerization initiators, desiccants (hygroscopic agents), curing accelerators, coupling agents, softening agents, colorants, flame retardant aids, antioxidants, and organic solvents. Among these, fillers, gap fillers, curing accelerators, polymerization initiators, and desiccants (hygroscopic agents) are preferred, with fillers and polymerization initiators being more preferred. By including fillers as additives, it is possible to suppress the intrusion of moisture and oxygen, and furthermore, to obtain effects such as reduced volume shrinkage during curing, reduced outgassing during curing or heating, improved mechanical strength, and control of thermal conductivity and fluidity. Therefore, including fillers as additives is very effective in maintaining stable output in various environments.

[0045] Furthermore, regarding the output characteristics and durability of photoelectric conversion elements, the effects of outgassing generated during the curing or heating of the sealing material, in addition to the effects of infiltrating moisture and oxygen, cannot be ignored. In particular, the effects of outgassing generated during heating have a significant impact on the output characteristics when stored in a high-temperature environment. By incorporating fillers, gap fillers, and desiccants into the sealing material, these materials themselves can suppress the infiltration of moisture and oxygen, and the amount of sealing material used can be reduced, thereby reducing outgassing. Incorporating fillers, gap fillers, and desiccants into the sealing material is effective not only during curing but also when storing photoelectric conversion elements in a high-temperature environment.

[0046] There are no particular restrictions on the filler material, and it can be appropriately selected depending on the purpose. Examples include crystalline or amorphous silica, silicate minerals such as talc, and inorganic fillers such as alumina, aluminum nitride, silicon nitride, calcium silicate, and calcium carbonate. Among these, hydrotalcite is particularly preferred. These may be used individually or in combination of two or more.

[0047] The average primary particle size of the filler is not particularly limited, but is preferably 0.1 μm or more and 10 μm or less, and more preferably 1 μm or more and 5 μm or less. When the average primary particle size of the filler is within the above preferred range, the effect of suppressing the intrusion of moisture and oxygen can be sufficiently obtained, the viscosity becomes appropriate, adhesion to the substrate and degassing performance are improved, and it is also effective in controlling the width of the sealing part and workability.

[0048] The content of the filler is preferably 10 to 90 parts by mass, and more preferably 20 to 70 parts by mass, relative to the entire sealing member (100 parts by mass). By having the content of the filler within the above preferred range, sufficient effect in suppressing the penetration of moisture and oxygen is obtained, the viscosity becomes appropriate, and adhesion and workability are also good.

[0049] The gap agent is also called a gap control agent or spacer agent. By including a gap agent as an additive, it becomes possible to control the gap of the sealed portion. For example, when a sealing member is applied to a first substrate or a first electrode, and a second substrate is placed on top of it to perform sealing, the gap of the sealed portion can be easily controlled because the gap agent is mixed into the sealing member, causing the gap to match the size of the gap agent.

[0050] The gap filler is not particularly limited, but is preferably granular with a uniform particle size and high solvent resistance and heat resistance, and can be appropriately selected depending on the purpose. The gap filler is preferably one that has high affinity with epoxy resin and has a spherical particle shape. Specifically, glass beads, silica fine particles, and organic resin fine particles are preferred. These may be used individually or in combination of two or more. The particle size of the gap filler can be selected according to the gap of the sealing part to be set, but is preferably 1 μm to 100 μm, and more preferably 5 μm to 50 μm.

[0051] The polymerization initiator is not particularly limited, but examples include polymerization initiators that initiate polymerization using heat or light, and can be appropriately selected depending on the purpose, such as thermal polymerization initiators and photopolymerization initiators. Thermal polymerization initiators are compounds that generate active species such as radicals and cations when heated, and examples include azo compounds such as 2,2'-azobisbutyronitrile (AIBN) and peroxides such as benzoyl peroxide (BPO). Examples of thermal cationic polymerization initiators include benzenesulfonic acid esters and alkylsulfonium salts. In the case of epoxy resins, photocationic polymerization initiators are preferably used as photopolymerization initiators. When a photocationic polymerization initiator is mixed with an epoxy resin and irradiated with light, the photocationic polymerization initiator decomposes, generating acid, which causes polymerization of the epoxy resin, and the curing reaction proceeds. Photocationic polymerization initiators have the effect of low volume shrinkage during curing, not being affected by oxygen inhibition, and having high storage stability.

[0052] Examples of photocatalytic polymerization initiators include aromatic diazonium salts, aromatic iodonium salts, aromatic sulfonium salts, metacerone compounds, and silanol-aluminum complexes. Additionally, photoacid generators that generate acid upon irradiation with light can also be used as polymerization initiators. These photoacid generators act as acids that initiate cationic polymerization and include ionic sulfonium salts and iodonium salts, among other onium salts, consisting of a cation and anion. These may be used individually or in combination of two or more.

[0053] The amount of polymerization initiator added is not particularly limited and may vary depending on the material used, but is preferably 0.5 parts by mass or more and 10 parts by mass or less, and more preferably 1 part by mass or more and 5 parts by mass or less, relative to the entire sealing member (100 parts by mass). By adding the amount within the above preferred range, curing can proceed appropriately, the amount of uncured material remaining can be reduced, and excessive outgassing can be prevented.

[0054] The desiccant (also called a moisture absorber) is a material that has the function of physically or chemically adsorbing and absorbing moisture, and by incorporating it into the sealing member, moisture resistance can be further enhanced and the effects of outgassing can be reduced. There are no particular restrictions on the desiccant, and it can be appropriately selected according to the purpose, but particulate materials are preferred, and examples of inorganic water-absorbing materials include calcium oxide, barium oxide, magnesium oxide, magnesium sulfate, sodium sulfate, calcium chloride, silica gel, molecular sieves, and zeolites. Among these, zeolites, which have a high moisture absorption capacity, are preferred. These may be used alone or in combination of two or more.

[0055] The curing accelerator (also called a curing catalyst) is a material that speeds up the curing process and is mainly used with thermosetting epoxy resins. There are no particular restrictions on the curing accelerator, and it can be appropriately selected depending on the purpose. Examples include tertiary amines or tertiary amine salts such as DBU (1,8-diazabicyclo(5,4,0)-undecene-7) and DBN (1,5-diazabicyclo(4,3,0)-nonene-5), imidazoles such as 1-cyanoethyl-2-ethyl-4-methylimidazole and 2-ethyl-4-methylimidazole, and phosphines or phosphonium salts such as triphenylphosphine and tetraphenylphosphonium·tetraphenylborate. These may be used alone or in combination of two or more.

[0056] The coupling agent is not particularly limited as long as it is a material that has the effect of increasing molecular bonding strength, and can be appropriately selected according to the purpose. Examples include silane coupling agents. Specifically, examples include silane coupling agents such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-(2-aminoethyl)3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)3-aminopropylmethyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, N-(2-(vinylbenzylamino)ethyl)3-aminopropyltrimethoxysilane hydrochloride, and 3-methacryloxypropyltrimethoxysilane. These may be used alone or in combination of two or more.

[0057] In the present invention, for example, a sheet-like adhesive can be used. A sheet-like adhesive is, for example, a sheet on which a resin layer has been formed in advance, and the sheet can be made of glass, a film with high gas barrier properties, or the like. Alternatively, the sheet may be formed using only the sealing resin. It is also possible to attach the sheet-like adhesive to the sealing film. It is also possible to create a structure with a hollow portion on the sealing film and then bond it to the device.

[0058] When sealing is performed using the aforementioned sealing film, it is positioned opposite the support so as to sandwich the photoelectric conversion device. There are no particular restrictions on the shape, structure, size, or type of the substrate of the sealing film, and it can be appropriately selected according to the purpose. The sealing film has a barrier layer formed on the surface of the substrate that prevents the passage of moisture and oxygen, and this layer may be formed on one side of the substrate or on both sides.

[0059] The barrier layer may be composed of a material whose main components are, for example, a metal oxide, a metal, or a mixture formed from a polymer and a metal alkoxide. Examples of the metal oxide include aluminum oxide, silicon oxide, and aluminum; examples of the polymer include polyvinyl alcohol, polyvinylpyrrolidone, and methylcellulose; and examples of the metal alkoxide include tetraethoxysilane, triisopropoxyaluminum, 3-glycidoxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanatetopropyltriethoxysilane.

[0060] The barrier layer may be transparent or opaque, for example. Furthermore, the barrier layer may be a single layer formed from a combination of the above materials, or a multi-layered structure. Known methods can be used to form the barrier layer, including vacuum deposition methods such as sputtering, dipping, roll coating, screen printing, spraying, and gravure printing.

[0061] [wiring] In order to efficiently extract the current generated by light, it is preferable to connect lead wires (wiring) to the electrodes and back electrode of the photoelectric conversion element (e.g., solar cell) of the present invention. The lead wires are connected to the first electrode and the second electrode using a conductive material such as solder, silver paste, or graphite. The conductive material may be used alone, or in a mixture of two or more types or in a laminated structure. Furthermore, the area to which the lead wires are attached may be covered with an acrylic resin or epoxy resin for physical protection.

[0062] Lead wires are a general term for wires used to electrically connect power sources, electronic components, and other elements in electrical circuits. Examples include vinyl-coated wires and enameled wires.

[0063] [application] The applications and methods of use of the photoelectric conversion element of the present invention are not particularly limited, and it can be widely used in the same applications as general photoelectric conversion elements (e.g., general solar cells). The photoelectric conversion element of the present invention (e.g., solar cell) can be applied to a power supply device by combining it with, for example, a circuit board that controls the generated current. Examples of devices that utilize a power supply device include electronic desktop calculators and solar-powered radio-controlled watches. It is also possible to apply the solar cell of the present invention as a power supply device to mobile phones, electronic paper, thermometers and hygrometers, etc. Furthermore, it can be used as an auxiliary power source to extend the continuous use time of rechargeable or battery-powered electrical appliances, or for nighttime use by combining it with a secondary battery. It can also be used as a self-contained power source that does not require battery replacement or power wiring. [Examples]

[0064] The following describes embodiments of the present invention. However, the present invention is not limited to the following embodiments.

[0065] [Synthesis Example 1] Synthesis of azulene-2-Bpin [ka] In a two-necked flask, bis(1,5-cyclooctadiene)diiridium(I) dichloride (sigma-aldrich, 683094, 336 mg, 0.50 mmol), azulene (Tokyo Chemical Industries, A0634, 1.40 g, 11.0 mmol), bis(pinacorato)diborone (Tokyo Chemical Industries, B1964, 78.1 mg, 0.50 mmol), and 2,2'-bipyridyl (Tokyo Chemical Industries, B0468, 78.1 mg, 0.50 mmol) were dissolved in cyclohexane (30 mL) under Ar gas, and the mixture was heated and stirred at 85°C for 14 hours. The reaction was stopped by adding saturated ammonium chloride aqueous solution (5 mL), and the organic components were extracted with dichloromethane. The organic layer was washed with water, dried over sodium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column colomatography (eluent: n-hexane / ethyl acetate = 20 / 1 to 5 / 1) to obtain 1.03 g (4.07 mmol, yield 37%) of the target product, azulene-2-Bpin.

[0066] [Synthesis Example 2] Synthesis of azulene-2-CN [ka] Azulene-2-Bpin (1.03 g, 4.07 mmol) obtained in Synthesis Example 1 was dissolved in dioxane, and chloroacetonitrile (283 μL, 338 mg, 4.48 mmol), (methanesulfonate-κO[2'-(methylamino)-2-biphenylyl]palladium-dicyclohexyl(2',6'-dimethoxy-2-biphenyl)phosphine (sigma-aldrich, 804282, 80.8 mg, 0.10 mmol), and sodium carbonate (474 ​​mg, 4.48 mmol) were dissolved in the ion. The mixture was added dropwise to 1.0 ml of replacement water under Ar gas while stirring. After the addition was complete, the mixture was heated and stirred at 80°C for 48 hours, and the reaction was stopped by adding 5 ml of saturated ammonium chloride aqueous solution. The organic components were extracted with ethyl acetate. The organic layer was washed with saturated sodium chloride aqueous solution and water, dried over sodium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column colloidography (eluent: n-hexane / ethyl acetate = 5 / 1) to obtain 383 mg (2.29 mmol, yield 56%) of the target product, azulene-2-CN.

[0067] [Synthesis Example 3] Synthesis of Azulene-2-HN3I [ka] To a borane-tetrahydrofuran complex (0.9 M THF solution, 4.4 mL, 4.0 mmol), a solution of azulene-2-CN (167 mg, 1.00 mmol) obtained in Synthesis Example 2 was dissolved in THF (4.0 mL) and added dropwise under Ar gas. After the addition was complete, the mixture was heated and stirred at 70°C for 16 hours, and the reaction was stopped by adding saturated sodium bicarbonate aqueous solution (2 mL). The organic components were extracted with dichloromethane. The organic layer was washed with saturated sodium chloride aqueous solution and water, dried over sodium sulfate, and concentrated under reduced pressure. The residue was dissolved in methanol, ammonium iodide (145 mg, 1.00 mmol) was added, and the mixture was stirred at room temperature for 1 hour. The solution was then concentrated under reduced pressure and recrystallized in a mixed solvent of 2-propanol and ethyl ether to obtain 119 mg (0.40 mmol, 40% yield) of the target product, azulene-2-NH3I. The result was a deep blue solid. 1H-NMR (400 MHz, DMSO-d6): δ 8.34 (d, J = 2.4 Hz, 2H), 7.65 (t, J = 1.4 Hz, 1H), 7.31 (s, 2H), 7.26 (t, J = 2.4 Hz, 2H), 3.31 (s, 2H), 3.25 (br, 4H); 13 C-NMR (100.6 MHz, methanol-d4): δ 148.7, 142.3, 137.9, 136.8, 124.6, 118.0, 41.3, 30.0; HRMS (APCI) (m / z): [M+H] + calcd. for C12H13N, 172.1121; found, 172.1124. 1 The H-NMR chart is shown in Figure 5. 13 The 1C-NMR chart is shown in Figure 6.

[0068] [Synthesis Example 4] Synthesis of azulene-6-Bpin [ka] The above azulene-6-Bpin was obtained according to the synthesis example described in H. Yorimitsu et al., Org. Lett., 2021, Vol.23, 4613.

[0069] [Synthesis Example 5] Synthesis of azulene-6-CN [ka] Azulene-6-CN was obtained from Azulene-6-Bpin using the same procedure as in Synthesis Example 2.

[0070] [Synthesis Example 6] Synthesis of Azulene-6-NH3I [ka] To a borane-tetrahydrofuran complex (0.9 M THF solution, 4.4 mL, 4.0 mmol), a solution of azulene-6-CN (167 mg, 1.00 mmol) obtained in Synthesis Example 5 was dissolved in THF (4.0 mL) and added dropwise under Ar gas. After the addition was complete, the mixture was heated and stirred at 70°C for 16 hours, and the reaction was stopped by adding saturated sodium bicarbonate aqueous solution (2 mL). The organic components were extracted with dichloromethane. The organic layer was washed with saturated sodium chloride aqueous solution and water, dried over sodium sulfate, and concentrated under reduced pressure. The residue was dissolved in methanol, ammonium iodide (145 mg, 1.00 mmol) was added, and the mixture was stirred at room temperature for 1 hour. The solution was then concentrated under reduced pressure and recrystallized in a mixed solvent of 2-propanol and ethyl ether to obtain 76.6 mg (0.259 mmol, yield 26%) of the target product, azulene-6-NH3I. The result was a deep blue solid. 1 H NMR (400 MHz, DMSO-d6): δ 8.37 (d, J = 2.4 Hz, 2H), 7.85 (d, J = 0.80 Hz, 1H), 7.39 (t, J = 0.80 Hz, 2H), 7.12 (d, J = 2.4 Hz, 2H), 3.16-3.14 (m, 2H), 3.08-3.04 (m, 2H); 13 C NMR (100.6 MHz, MeOD): δ 147.6, 140.9, 137.9, 137.1, 124.8, 119.9, 42.6, 40.5; HRMS (APCI) (m / z): [M+H] + calcd. for C 12 H 13 N, 172.1121; found, 172.1118. 1 The H-NMR chart is shown in Figure 7. 13 The 1C-NMR chart is shown in Figure 8.

[0071] Figures 3 and 4 illustrate the passivation process using azulene compounds. Azulene has a skeleton in which five-membered rings and seven-membered rings of aromatic hydrocarbons are bonded together, and it is known that the five-membered ring is easily polarized to anions and the seven-membered ring is easily polarized to cationic states. When a substituent with a quaternary ammonium salt is introduced on the five-membered ring side, the quaternary ammonium salt fills the defects in the perovskite layer, and the cationically polarized seven-membered ring is positioned facing the layer opposite to the perovskite layer. By forming a hole transport layer on the cationically polarized side, hole transport from the perovskite layer is facilitated (Figure 3). On the other hand, when a passivation film is formed with a compound in which a substituent with a quaternary ammonium salt is introduced on the seven-membered ring, the ammonium salt is positioned in the perovskite layer, filling the defects in the perovskite layer, and the anionically polarized five-membered ring is positioned facing the layer opposite to the perovskite layer. By forming an electron transport layer in this direction, electron transport is facilitated (Figure 4). Therefore, in the normal structure, an azulene compound having a quaternary ammonium salt in a 7-membered ring is effective as a passivation material inserted at the interface between the perovskite layer and the hole transport layer, while in the reverse structure, an azulene compound having a quaternary ammonium salt in a 5-membered ring is effective as a passivation material inserted at the interface between the perovskite layer and the hole transport layer.

[0072] [Example 1] The photoelectric conversion element, a solar cell, of the present invention was fabricated (manufactured) as follows.

[0073] An ITO glass substrate (25mm x 24.5mm, Geomatec) was ultrasonically cleaned for 15 minutes each with 2-propanol, acetone, Semicoclean 56 (Fulci Chemical, display cleaning solution), water, and 2-propanol, followed by plasma treatment. Next, 300 μL of a water-soluble SnO2 colloidal solution (15% SnO2 colloidal solution diluted 1:1 with pure water and passed through a PTFE filter) was dropped onto the substrate as an electron transport layer, and the film was formed using spin coating (3000 rpm, 20 seconds), followed by heating and drying at 150°C for 30 minutes. The substrate was moved to a glove box, and as a perovskite precursor solution, cesium iodide, methylamine bromide, lead iodide, lead bromide, and formamidine iodide were dissolved in a mixed solvent of DMF and DMSO (volume ratio 10:3). Next, a solution of cesium iodide (0.738 g), formamidine iodide (7.512 g), methylamine bromide (0.905 g), lead iodide (23.888 g), and lead bromide (1.022 g) dissolved in DMF (40.0 mL) and dimethyl sulfoxide (DMSO, 12.0 mL) was deposited on the substrate using spin coating. Spin coating was performed at 3000 rpm, and chlorobenzene (0.3 mL) was added dropwise 30 seconds after the start. After that, it was heated at 150°C for 10 minutes to obtain a perovskite layer (photoelectric conversion layer). Next, 20 μL of a 2-propanol solution (0.1 mM) of azulene-6-NH3I obtained in Synthesis Example 6 was dropped onto the previously prepared perovskite layer, and a passivation layer was formed using spin coating (3000 rpm, 30 seconds). Next, a solution was prepared by dissolving the hole transport material Spiro-OMeTAD (72.3 mg), [Tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine)cobalt(III)tris(bis(trifluoromethylsulfonyl)imide)] (FK209, Fujifilm Wako Pure Chemical Industries, 13.5 mg), 4-t-butylpyridine (28.8 μL), and LiTFSI (9.1 mg) in 1 mL of chlorobenzene. After stirring for 30 minutes, the solution was filtered through a PTFE filter, and 90 μL was spin-coated onto a perovskite layer (4000 rpm with a slope of 4 seconds for 30 seconds, then stopped with a slope of 4 seconds). Finally, it was heated and dried at 70°C for 30 minutes. Lastly, 80 nm of gold was formed by vacuum deposition to obtain a perovskite solar cell element.Furthermore, Nagase ChemteX XNR5516 was applied to the outer periphery of the photoelectric conversion element, bonded to glass under an inert gas atmosphere, and irradiated with UV light to fabricate a sealed device.

[0074] [Evaluation of Solar Cell Characteristics] The photoelectric conversion characteristics of the upper and lower solar cells fabricated in Example 1 were measured using a method compliant with the output measurement method for silicon crystalline solar cells specified in JISC8913:1998. The results are shown in Table 1. A solar simulator (SMO-250III, manufactured by Spectrometer Co., Ltd.) combined with an air mass filter equivalent to AM1.5G was used with a secondary reference Si solar cell at 100 mW / cm². 2 The light intensity was adjusted to a light source for measurement, and while irradiating a test sample of a perovskite solar cell (a sealed device fabricated in Example 1) with light, the IV curve characteristics were measured using a source meter (Keithley Instruments Inc., 2400 general-purpose source meter). From the IV curve characteristics measurement, the short-circuit current (Isc), open-circuit voltage (Voc), fill factor (FF), and short-circuit current density (Jsc) and photoelectric conversion efficiency (PCE) were determined according to Equations 1 and 2 below. In addition, a continuous light irradiation test was conducted at 100 mW / cm². 2 A 500-hour continuous irradiation test was conducted using a Suntest XLS+ adjusted to the specified light intensity. The maintenance rate of the conversion efficiency measured before and after this test is shown in Table 1.

[0075] Equation 1: Short-circuit current density (Jsc; mA / cm²) 2 )=Isc(mA) / Effective photosensitive area S(cm 2 ) Equation 2: Photoelectric conversion efficiency (PCE; %) = Voc(V) × Jsc(mA / cm) 2 ) × FF × 100 / 100 (mW / cm 2 )

[0076] [Example 2] The photoelectric conversion element for Example 2 was fabricated and evaluated in the same manner as in Example 1, except that azulene-6-NH3I in Example 1 was replaced with azulene-6-NH3Br as shown below. The results of the solar cell characteristics are shown in Table 1 below.

[0077] [ka]

[0078] [Example 3] The photoelectric conversion element for Example 2 was fabricated and evaluated in the same manner as in Example 1, except that azulene-6-NH3I was replaced with azulene-5-NH3I. The results of the solar cell characteristics are shown in Table 1 below.

[0079] [ka]

[0080] [Example 4] The photoelectric conversion element for Example 2 was fabricated and evaluated in the same manner as in Example 1, except that the compound azulene-6-NH3I in Example 1 was replaced with the compound azulene-6-NH3Br-tert-Butyl. The results of the solar cell characteristics are shown in Table 1 below.

[0081] [ka]

[0082] [Comparative Example 1] A photoelectric conversion element was fabricated and evaluated in the same manner as in Example 1, except that no passivation film was formed using the compound azulene-6-NH3I, without the use of any other compound. The results of the solar cell characteristics are shown in Table 1 below.

[0083] [Comparative Example 2] A photoelectric conversion element was fabricated and evaluated in the same manner as in Example 1, except that the compound azulene-6-NH3I in Example 1 was replaced with n-hexylammonium bromide (Tokyo Chemical Industries, H1679). The results of the solar cell characteristics are shown in Table 1 below.

[0084] [Table 1]

[0085] [Example 5] A 0.1 mmol / L DMF solution containing compound B-01 (shown below) was placed on the ITO of an ITO glass substrate (a glass substrate on which the first electrode was formed as a support), and a monolayer (hole transport layer) was formed on the ITO (first electrode) using a spin coater (3,000 rpm, 30 seconds). Next, a solution of cesium iodide (0.738 g), formamidine iodide (7.512 g), methylamine bromide (0.905 g), lead iodide (23.888 g), and lead bromide (1.022 g) dissolved in DMF (40.0 mL) and dimethyl sulfoxide (DMSO, 12.0 mL) was deposited on the substrate using spin coating. Spin coating was performed at 3000 rpm, and chlorobenzene (0.3 mL) was added dropwise 30 seconds after the start. Subsequently, the mixture was heated at 150°C for 10 minutes to obtain a perovskite layer (photoelectric conversion layer). Next, 20 μL of a 2-propanol solution (0.1 mM) of azulene-2-NH3I obtained in specific example synthesis 3 was dropped onto the previously prepared perovskite layer, and a passivation layer was formed using spin coating (3000 rpm, 30 seconds). Then, C60 (20 nm, electron transport layer), vasocuproin (BCP, 8 nm, electron injection layer), and Ag (100 nm, second electrode) were deposited by vacuum deposition to fabricate a photoelectric conversion element. Furthermore, Nagase ChemteX XNR5516 was coated on the outer periphery of the photoelectric conversion element, bonded to glass under an inert gas atmosphere, and irradiated with UV to fabricate a sealed device. After device fabrication, the solar cell characteristics of the photoelectric conversion element were evaluated. The performance is shown in Table 2. In addition, a continuous light irradiation test was performed at 100 mW / cm². 2 A continuous irradiation test of 500 hours was conducted using a Suntest XLS+ adjusted to the specified light intensity. The maintenance rate of the conversion efficiency measured before and after this test is shown in Table 2.

[0086] [ka]

[0087] [Example 6] The photoelectric conversion element of Example 2 was fabricated and evaluated in the same manner as in Example 5, except that azulene-2-NH3I was replaced with azulene-2-NH3Br. The results of the solar cell characteristics are shown in Table 2 below.

[0088] [ka]

[0089] [Example 7] The photoelectric conversion element of Example 2 was fabricated and evaluated in the same manner as in Example 1, except that azulene-2-NH3I in Example 5 was replaced with azulene-1-NH3I. The results of the solar cell characteristics are shown in Table 2 below.

[0090] [ka]

[0091] [Example 8] The photoelectric conversion element of Example 2 was fabricated and evaluated in the same manner as in Example 1, except that azulene-2-NH3I in Example 5 was replaced with azulene-2-NH3Br-tetr-Butyl. The results of the solar cell characteristics are shown in Table 2 below.

[0092] [ka]

[0093] [Comparative Example 3] In Example 1, a photoelectric conversion element was fabricated and evaluated in the same manner as in Example 5, except that no passivation film was formed using azulene-2-NH3I without any additives. The results of the solar cell characteristics are shown in Table 2 below.

[0094] [Comparative Example 4] A photoelectric conversion element was fabricated and evaluated in the same manner as in Example 5, except that azulene-2-NH3I in Example 1 was replaced with n-hexylammonium bromide. The results of the solar cell characteristics are shown in Table 2 below.

[0095] [Comparative Example 5] A photoelectric conversion element was fabricated and evaluated in the same manner as in Example 5, except that azulene-2-NH3I in Example 1 was replaced with 2-phenylethylammonium iodide (Tokyo Chemical Industries, P2213). The results of the solar cell characteristics are shown in Table 2 below.

[0096] [Table 2]

[0097] [Example 9] In Example 5, instead of placing 100 μL of a DMF solution (0.1 mmol / L) containing compound B-01 on the ITO of an ITO glass substrate (a glass substrate on which the first electrode is formed as a support) and forming a monolayer (hole transport layer) on the ITO (first electrode) using a spin coater (3,000 rpm, 30 seconds), an ITO-NiO glass substrate was used, in which 30 nm of NiO was sputtered onto the ITO of the ITO glass substrate. A monolayer of the DMF solution (0.1 mmol / L) containing compound B-01 was then formed on the NiO of the ITO-NiO substrate. Otherwise, a photoelectric conversion element was fabricated and evaluated in the same manner as in Example 5. The results of the solar cell characteristics are shown in Table 3 below.

[0098] [Example 10] The photoelectric conversion element of Example 2 was fabricated and evaluated in the same manner as in Example 1, except that compound B-01 in Example 9 was replaced with compound B-02 shown below. The results of the solar cell characteristics are shown in Table 3 below.

[0099] [ka]

[0100] [Table 3]

[0101] As described above, this embodiment confirms that good solar cell characteristics can be obtained by using the configuration of the photoelectric conversion element of the present invention.

[0102] [Solar modules] A first electrode 32 was formed on the surface of a glass substrate 31, and the first electrode 32 was patterned into the shape shown in Figure 9 using a laser processing device. A single-molecule hole transport layer was formed on this first electrode 32, and a perovskite layer was obtained as a photoelectric conversion layer. Next, an electron transport layer was deposited by vacuum deposition. Subsequently, the photoelectric conversion layer (perovskite layer) was etched using a laser processing device to form a pattern of the photoelectric conversion layer (perovskite layer) 33 as shown in Figure 10. Finally, 70 nm of Ag was formed by vacuum deposition, and the second electrode 44 was etched using a laser processing device to obtain a photoelectric conversion module (perovskite solar cell module) with the shape shown in Figures 11 and 12.

[0103] The present invention has been described above using embodiments and examples. However, the present invention is not limited to the embodiments and examples described above, and can be arbitrarily and appropriately combined, modified, or selected and adopted as necessary, without departing from the spirit of the present invention. [Industrial applicability]

[0104] As described above, the present invention provides a photoelectric conversion element that exhibits excellent photoelectric conversion characteristics. The photoelectric conversion element of the present invention is useful, for example, as a solar cell. The applications and methods of use of the photoelectric conversion element of the present invention are not particularly limited, and it can be applied to a wide range of fields in the same applications and methods as general photoelectric conversion elements (for example, general solar cells). [Explanation of symbols]

[0105] 10, 20 Photoelectric conversion elements 11, 21 Support 12, 22 First electrode 13, 23 Electron transport layer 14, 24 Photoelectric conversion layer 15, 25 Hole transport layer 16, 26 Second electrode

Claims

1. A compound having multiple aromatic hydrocarbon rings or heterocycles fused together, each ring being negatively or positively polarized, and having an amine or a salt thereof as a substituent.

2. The compound according to claim 1, characterized in that the compound is represented by the following general formula (I). 【Chemistry 1】 (In general formula (I), R １ (where represents a hydrogen atom, alkyl group, alkoxy group, aryl group, or halogen atom, and may be present individually or in multiples.) (Z is a substituent having an amine or a salt thereof, and may be bonded to the aromatic ring by a single bond or via a divalent linking group, and may be present individually or in multiples.)

3. The compound according to claim 2, characterized in that the compound represented by the general formula (I) is the compound represented by the general formula (II) below. 【Chemistry 2】 (In general formula (II), R １ (where represents a hydrogen atom, alkyl group, alkoxy group, aryl group, or halogen atom, and may be present individually or in multiples.) (Z is a substituent having an amine or a salt thereof, and may be bonded to the aromatic ring by a single bond or via a divalent linking group, and may be present individually or in multiples.)

4. The compound according to claim 3, characterized in that the compound represented by the general formula (II) is the compound represented by the general formula (III) below. 【Transformation 3】 (In general formula (III), R １ 'H' represents a hydrogen atom, alkyl group, alkoxy group, aryl group, or halogen atom, and may be present individually or in combination of multiple elements. ２ (The amine can be the amine alone or as a salt.)

5. The compound according to claim 2, characterized in that the compound represented by the general formula (I) is the compound represented by the general formula (IV) below. 【Chemistry 4】 (In general formula (IV), R １ (where represents a hydrogen atom, alkyl group, alkoxy group, aryl group, or halogen atom, and may be present individually or in multiples.) (Z is a substituent having an amine or a salt thereof, and may be bonded to the aromatic ring by a single bond or via a divalent linking group, and may be present individually or in multiples.)

6. The compound according to claim 5, characterized in that the compound represented by the general formula (IV) is the compound represented by the general formula (V) below. 【Transformation 5】 (In general formula (V), R １ 'H' represents a hydrogen atom, alkyl group, alkoxy group, aryl group, or halogen atom, and may be present individually or in combination of multiple elements. ２ (The amine can be the amine alone or as a salt.)

7. Each layer is formed directly or indirectly on the support in a first order, or a second order which is the reverse of the first order, consisting of a first electrode layer, a hole transport layer, a perovskite layer, an electron transport layer, and a second electrode layer. A photoelectric conversion element in which the compound according to any one of claims 1 to 6 is present at the interface between the perovskite layer and the electron transport layer or the hole transport layer.

8. The photoelectric conversion element according to claim 7, characterized in that the hole transport layer contains a compound represented by the following chemical formula (VI). Ar-(L-Q)n ... (VI) In the above chemical formula (VI), Ar is a structure containing an aromatic ring, and the atoms constituting the aromatic ring may contain heteroatoms, and Ar may have substituents other than -L-Q. n is an integer of 1 or more, and if n is 2 or more, the structures represented by -L-Q may be the same or different from each other. L is a divalent linking group or a single bond that connects Ar and Q. Q is a group that can chemically bond or hydrogen bond with a metal oxide.

9. The photoelectric conversion element according to claim 8, characterized in that the metal oxide bonded with the compound represented by the chemical formula (VI) is a p-type metal oxide.

10. The photoelectric conversion element according to claim 9, characterized in that the metal oxide is one of nickel oxide, copper oxide, copper-aluminum oxide, nickel-aluminum oxide, or copper-nickel oxide.

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