Photoelectric conversion element

Abstract

To provide a photoelectric conversion element that exhibits excellent photoelectric conversion properties.SOLUTION: A photoelectric conversion element contains a bicyclo compound represented by the following general formula (I), a tautomer or stereoisomer thereof, or a salt thereof. In the general formula (I), Z1 and Z2 may be the same or different and each represent C-R or a nitrogen atom. X1, X2, and X3 may be the same or different and each represent a divalent linking group that forms a ring structure together with the central bicyclo ring.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a photoelectric conversion element.

Background Art

[0002] In recent years, as clean energy, photovoltaic power generation has attracted attention, and the development of solar cells has been progressing. As one of them, as a next-generation solar cell that can be manufactured at low cost, a solar cell using a perovskite material as a light absorption layer has rapidly attracted attention. For example, in Non-Patent Document 1, a solution-type solar cell using a perovskite material as a light absorption layer has been reported. In addition, Non-Patent Document 2 also reports that a solid-type perovskite solar cell exhibits high efficiency.

[0003] In order to further improve the photoelectric conversion efficiency of perovskite solar cells, a method of passivating (inactivating) the surface of the perovskite layer with phenylethylamine iodide has been reported (Non-Patent Document 3). In addition, a method using a thiol compound has also been reported (Non-Patent Document 4).

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Non-Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the conventional perovskite solar cells do not have sufficient photoelectric conversion efficiency.

[0006] Therefore, an object of the present invention is to provide a photoelectric conversion element exhibiting excellent photoelectric conversion characteristics.

Means for Solving the Problems

[0007] In order to achieve the above object, the photoelectric conversion element of the present invention is a photoelectric conversion element containing a bicyclic compound represented by the following general formula (I), a tautomer or stereoisomer thereof, or a salt thereof.

Chemical formula

Effects of the Invention

[0008] According to the present invention, a photoelectric conversion element exhibiting excellent photoelectric conversion characteristics can be provided.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

BEST MODE FOR CARRYING OUT THE INVENTION

[0010] Next, the present invention will be described in more detail with examples. However, the present invention is not limited by the following description.

[0011] The compound of the present invention is, for example, a compound represented by the following chemical formula (I), a tautomer or stereoisomer thereof, or a salt thereof.

Chemical formula

[0012] In the bicyclic compounds of the present invention, the chain-like group or atomic group (for example, hydrocarbon groups such as alkyl groups and unsaturated aliphatic hydrocarbon groups) may be linear or branched unless otherwise specified, and the number of carbon atoms is not particularly limited. For example, it may be 1 to 40, 1 to 32, 1 to 24, 1 to 18, 1 to 12, 1 to 6, or 1 to 2 (2 or more in the case of unsaturated hydrocarbon groups). Further, in the present invention, the number of ring members (the number of atoms constituting the ring) of the cyclic group or atomic group (for example, an aromatic ring, an aromatic group, etc., such as an aryl group, a heteroaryl group, etc.) is not particularly limited. For example, it may be 5 to 32, 5 to 24, 6 to 18, 6 to 12, or 6 to 10. Further, when isomers exist in substituents or the like, any isomer may be used unless otherwise specified. For example, when simply referred to as a "naphthyl group", it may be a 1-naphthyl group or a 2-naphthyl group.

[0013] In the present invention, the "substituent" is not particularly limited. For example, it includes an alkyl group, an unsaturated aliphatic hydrocarbon group, an alkoxy group, an aralkyl group, an aryl group, a heteroaryl group, a halogen, a hydroxy group (-OH), a mercapto group (-SH), an alkylthio group (-SR, where R is an alkyl group), a sulfo group, a nitro group, a diazo group, a cyano group, a trifluoromethyl group, and the like. Further, in the present invention, when isomers such as tautomers or stereoisomers (e.g., geometric isomers, conformational isomers, and optical isomers) exist in the compound, any isomer can be used in the present invention unless otherwise specified.

[0014] Hereinafter, specific examples of the bicyclic compounds of the present invention are shown in (A-1) to (A-60). However, the present invention is not limited to the following examples.

[0015]

Chemical formula

[0016]

Chemical formula

[0017] [Chemistry]

[0018] [Chemistry]

[0019] [Chemistry]

[0020] [Chemistry]

[0021] A film made of the bicyclic compound is formed between the photoelectric conversion layer 14 and the electron transport layer 15. Since various crystal defects exist on the surface and grain boundaries of the photoelectric conversion layer 14, it is effective to provide a film made of the bicyclic compound between the photoelectric conversion layer 14 and the electron transport layer 15 in order to passivate these defects. Since this interface layer may become a resistance component if it is formed thick, it is preferably formed thin. The forming method is not particularly limited, and examples include spin coating, inkjet, casting, spray coating, or vacuum deposition of the above-mentioned bicyclic compound using a solution in which the bicyclic compound is dissolved.

[0022] [Photoelectric conversion element] The photoelectric conversion element of the present invention is not particularly limited, and examples thereof include the first photoelectric conversion element and the second photoelectric conversion element of the present invention described below. The first photoelectric conversion element (10) of the present invention is The first electrode (12), the electron transport layer (13), the photoelectric conversion layer (14), the hole transport layer (15), and the second (16) electrode are laminated in the above order, The photoelectric conversion layer (14) includes a perovskite structure, A film made of the bicyclic compound is formed at the interface between the photoelectric conversion layer (14) and the hole transport layer (15).

[0023] The second photoelectric conversion element (20) of the present invention is a first electrode (22), a hole transport layer (25), a photoelectric conversion layer (24), an electron transport layer (23), and a second electrode (26) are laminated in the above order, the photoelectric conversion layer (24) includes a perovskite structure, and a film made of the bicyclic compound is formed at the interface between the photoelectric conversion layer (24) and the electron transport layer (23).

[0024] The photoelectric conversion element of the present invention is, for example, such that the first electrode, the hole transport layer, the photoelectric conversion layer, the electron transport layer, and the second electrode are laminated in the above order. The photoelectric conversion element of the present invention may or may not include other components other than the first electrode, the hole transport layer, the photoelectric conversion layer, the electron transport layer, and the second electrode. For example, the first electrode and the hole transport layer may be directly laminated without other components therebetween, or other components may be present therebetween. Similarly, the hole transport layer and the photoelectric conversion layer may be directly laminated without other components therebetween, or other components may be present therebetween. Similarly, the photoelectric conversion layer and the electron transport layer may be directly laminated without other components therebetween, or other components may be present therebetween. Similarly, the electron transport layer and the second electrode may be directly laminated without other components therebetween, or other components may be present therebetween.

[0025] Hereinafter, the configuration of the photoelectric conversion element of the present invention and each component will be described more specifically with examples. However, the photoelectric conversion element of the present invention is not limited to the following examples. In the following, mainly, the case where the photoelectric conversion element of the present invention is a solar cell will be described.

[0026] FIG. 1 and FIG. 2 show cross-sectional views of an example of the configuration of the photoelectric conversion element of the present invention. Note that FIGS. 1 and 2 are schematically drawn with appropriate omissions, exaggerations, etc. for convenience of explanation. As shown in the figures, in this photoelectric conversion element 10, a first electrode 12, an electron transport layer 13, a photoelectric conversion layer 14, a hole transport layer 15, and a second electrode 16 are laminated in the above order on a support (also referred to as a substrate or a base material) 11. In the photoelectric conversion element 20, a first electrode 22, a hole transport layer 25, a photoelectric conversion layer 24, an electron transport layer 23, and a second electrode 26 are laminated in the above order on a support (also referred to as a substrate or a base material) 21.

[0027] [Supports 11, 21] The supports 11 and 21 are not particularly limited, and for example, a substrate that can be used for a photoelectric conversion element such as a general solar cell may be appropriately used. Examples of the substrate include glass, a plastic plate, a plastic film, and an inorganic crystal. Further, a substrate having at least one type of film such as a metal film, a semiconductor film, a conductive film, and an insulating film formed on a part or all of the surface of these substrates can also be preferably used as the 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 a photoelectric conversion element such as a general solar cell.

[0028] [First electrodes 12, 22] The first electrodes 12 and 22 are, for example, layers that support the hole transport layers 13 and 23 and have a function of extracting holes from the photoelectric conversion layers 14 and 24. Further, the first electrodes 12 and 22 are, for example, layers that act as a cathode (positive electrode).

[0029] 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 be, for example, transparent electrodes formed from a conductor. The transparent electrode is not particularly limited, but for example, a tin-doped indium oxide (ITO) film, an impurity-doped indium oxide (In 2 O 3)A film, an impurity-doped zinc oxide (ZnO) film, a fluorine-doped tin dioxide (FTO) film, a laminated film formed by laminating two or more of these, gold, silver, copper, aluminum, tungsten, titanium, chromium, nickel, cobalt, etc. may be mentioned. These may be used alone or as a mixture of two or more, and may be in a single layer or laminated. Also, these films may function as, for example, a diffusion prevention layer. The thickness of the first electrode 12 is not particularly limited, but it is preferably adjusted so that the sheet resistance is 5 to 15 Ω / square (per unit area). The method of forming the first electrodes 12 and 22 is not particularly limited, but can be obtained by a known film-forming method according to the material to be formed, for example. Also, the shape of the first electrodes 12 and 22 is not particularly limited, and may be, for example, in a film shape or formed in a lattice shape such as a mesh shape. The method of forming the first electrodes 12 and 22 on the supports 11 and 21 is not particularly limited, and a known method may be used, for example, and vacuum film formation such as vacuum evaporation or sputtering is preferable. Also, a patterned first electrode 12 may be used. The patterning method is not particularly limited, and examples include a method of immersing in a laser or an etching solution, a method of patterning using a mask during vacuum film formation, etc., and any method may be used in the present invention. Also, the first electrodes 12 and 22 may be used in combination with a metal wiring or the like for the purpose of reducing the electrical resistance value. The material of the metal wiring (metal lead wire) is not particularly limited, and examples include aluminum, copper, silver, gold, platinum, nickel, etc. The metal lead wire can be formed on the first substrate by, for example, evaporation, sputtering, crimping, etc., and an ITO or FTO layer can be provided thereon, or can be used in combination by providing it on ITO or FTO.

[0030] [Hole transport layers 15, 25] The hole transport layers 15 and 25 are layers having the function of transporting charges. For the hole transport layers 15 and 25, for example, conductors, semiconductors, organic hole transport materials, etc. can be used. The organic hole transport material can function as a hole transport material that receives holes from the perovskite layer (photoelectric conversion layer) 14 and 24 and transports the holes. As the conductor and the semiconductor, an inorganic hole transport material or the organic hole transport material is used. As the inorganic hole transport material, for example, compound semiconductors containing monovalent copper such as CuI, CuInSe 2 , CuS, etc.; compound semiconductors containing metals other than copper such as GaP, NiO, CiO, FeO, Bi 2 O 3 , MoO 3 , Cr 2 O, etc. Among them, from the viewpoint of more efficiently receiving only holes and obtaining a higher hole mobility, a semiconductor containing monovalent copper is preferable, and CuI or CuSCN is more preferable. As the organic hole transport material, for example, polythiophene derivatives such as poly-3-hexylthiophene (P3HT), 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. can be mentioned. Among them, from the viewpoint of more efficiently receiving only holes and obtaining a higher hole mobility, triphenylamine derivatives, fluorene derivatives, etc. are preferable, and PTAA, Spiro-OMeTAD, etc. are more preferable.

[0031] Furthermore, for the purpose of further improving the hole transport characteristics, the organic hole transport material may include, for example, 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-N-[(trifluoromethane)sulfonyl]butanesulfonylamide, nonafluoro-N-[(trifluoromethane)sulfonyl]butanesulfonylamide, lithium N,N-hexafluoro-1,3-disulfonylimide, sodium N,N-hexafluoro-1,3-disulfonylimide, trifluoromethylsulfonyloxy silver, NOSbF 6 , SbCl 5 , SbF 5 , and oxidizing agents such as tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine)cobalt(III) tri[bis(trifluoromethane)sulfonimide]. In addition, the hole transport layers 15 and 25 may contain, for example, basic compounds such as tert-butylpyridine (TBP), 2-picoline, and 2,6-lutidine. The contents of the oxidizing agent and the basic compound can be, for example, the amounts conventionally and usually used. From the viewpoint of more efficiently receiving only holes and obtaining a higher hole mobility, the film thicknesses of the hole transport layers 15 and 25 are preferably, for example, 1 to 500 nm, and more preferably 2 to 300 nm. The method of forming the hole transport layers 15 and 25 is preferably carried out, for example, in a dry atmosphere. For example, a solution containing an organic hole transport material is applied (spin-coated, etc.) onto the perovskite layer (light absorption layer) in a dry atmosphere and heated at 30 to 180°C, particularly 100 to 150°C.

[0032] In addition, as the hole transport layer 25 in the inverted structure, for example, it is also possible to use a hole transport compound that forms a single molecular layer (hereinafter also referred to as "single molecular hole transport compound"). As the single molecular hole transport compound, for example, in the inverted structure, it is desirable to have an anchor that chemically bonds to ITO or the like, which is a transparent electrode. Examples of the anchor include a phosphonic acid group (-P=O(OH) 2 ), a carboxy group (-COOH), a sulfo group (-SO 3 H), a boronic acid group (-B(OH) 2 ), a trihalosilyl group (-SiX 3 , where X is a halogen atom), or a trialkoxysilyl group (-Si(OR) 3 , where R is an alkyl group), etc. Among these, in particular, a phosphonic acid group, a trihalosilyl group, and a trialkoxysilyl group are preferable.

[0033] The method for forming the hole transport layer 25 using the above-mentioned single-molecule hole transport material is not particularly limited. For example, the hole transport layer 25 can be formed by adsorbing the single-molecule hole transport compound on the first electrode 22 to form a single-molecular layer. The method for adsorbing the single-molecule hole transport compound on the first electrode 22 to form a single-molecular layer is not particularly limited. For example, the single-molecule hole transport compound can be dissolved in a solvent and then brought into contact with and bonded to the first electrode 22. The bonding between the single-molecule hole transport compound and the first electrode 22 is not particularly limited and can be either a physical bond or a chemical bond. The type of the bond is also not particularly limited and can be, for example, any of a hydrogen bond, an ester bond, a chelate bond, etc. The solvent for dissolving the single-molecule hole transport compound is also not particularly limited and can be, for example, either water or an organic solvent, or both. More specifically, examples of the solvent include water; alcohols such as methanol, ethanol, 2-propanol; ethers such as diethyl ether, diisopropyl ether; ketones such as acetone, methyl isobutyl ketone; esters such as ethyl acetate, isobutyl acetate, γ-butyrolactone; heterocycles such as tetrahydrofuran, thiophene; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone; sulfoxides such as dimethyl sulfoxide; sulfones such as diethyl sulfone, sulfolane; nitriles such as acetonitrile, 3-methoxypropionitrile; aromatic compounds such as benzene, toluene, chlorobenzene; halogenated solvents such as dichloromethane, chloroform; fluorine-based solvents such as chlorofluorocarbon, hydrochlorofluorocarbon, hydrofluorocarbon. These can be used alone or in a mixture of two or more kinds.

[0034] The specific method for adsorbing the monomolecular hole transporting compound onto the first electrode 22 to form a monomolecular layer is not particularly limited, and examples thereof include known methods such as dipping method, spraying method, spin coating method, and bar coating method. The temperature during adsorption is not particularly limited, but preferably -20°C to 100°C, more preferably 0°C to 50°C. The adsorption time is also not particularly limited, but for example, 1 second to 48 hours is preferable, and 10 seconds to 1 hour is more preferable. Further, after the adsorption treatment, for example, washing may or may not be performed. The method of washing is not particularly limited, and for example, known methods may be appropriately used.

[0035] After the adsorption treatment or after the washing, heat treatment may or may not be performed. The temperature of the heat treatment is preferably 50°C to 150°C, more preferably 70°C to 120°C. The heat treatment time is preferably 1 second to 48 hours, more preferably 10 seconds to 1 hour. Further, this heat treatment may be performed, for example, in the atmosphere or in a vacuum.

[0036] When adsorbing the monomolecular hole transporting compound onto the first electrode 22, for example, a co-adsorbent may or may not be used in combination. The co-adsorbent can be added, for example, when the electrode surface cannot be completely covered only with the monomolecular hole transporting compound or for the purpose of inhibiting the interaction between the monomolecular hole transporting compounds.

[0037] The co-adsorbent is not particularly limited, and examples thereof 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, acetic acid, propionic acid, isobutyric acid, nonanoic acid, fluoroacetic acid, α-chloropropionic acid, glyoxylic acid, chenodeoxycholic acid, etc. These may be used alone or in a mixture of two or more.

[0038] The method for adsorbing the co-adsorbent onto the first electrode 22 is not particularly limited. However, similar to the monomolecular hole transport compound, a method of dissolving it in a solvent and then adsorbing it is preferred. The solvent is also not particularly limited. For example, it may be the same as the aforementioned solvents exemplified for the monomolecular hole transport compound. Further, the co-adsorbent may be adsorbed by immersing the first electrode 22 in a solvent in which the co-adsorbent is dissolved after the monomolecular hole transport compound has been adsorbed onto the substrate once, or a mixture dissolved in an organic solvent together with the monomolecular hole transport compound may be used.

[0039] [Electron transport layers 13, 23] The materials used for the electron transport layers 13 and 23 are not particularly limited and can be appropriately selected according to the purpose. However, semiconductor materials are preferred. The semiconductor materials are not particularly limited, and known ones can be used. For example, elemental semiconductors, compound semiconductors, organic n-type semiconductors, etc. can be mentioned.

[0040] The elemental semiconductor is not particularly limited. For example, silicon, germanium, etc. can be mentioned.

[0041] The compound semiconductor is not particularly limited. For example, 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. can be mentioned. Other compound semiconductors include phosphides of zinc, gallium, indium, cadmium, etc., gallium arsenide, copper-indium-selenide, copper-indium-sulfide, etc.

[0042] The organic n-type semiconductor is not particularly limited. For example, it can include perylene tetracarboxylic dianhydride, perylene tetracarboxydiimide compounds, naphthalenediimide-thiophene copolymers, benzobisimidazole benzophenanthroline polymers, C60, C70, fullerene compounds such as PCBM ([6,6]-phenyl-C61-butyric acid methyl ester), carbonyl bridge-bithiazole compounds, Alq3 (tris(8-quinolinolato)aluminum), triphenylene bipyridyl compounds, silole compounds, oxadiazole compounds, and the like.

[0043] Among the aforementioned materials used for the electron transport layers 13 and 23, an organic n-type semiconductor is particularly preferred.

[0044] The materials used for forming the electron transport layers 13 and 23 may be used alone or in combination of two or more. Also, the crystal form of the semiconductor material is not particularly limited and can be appropriately selected according to the purpose. It may be a single crystal, a polycrystal, or an amorphous material.

[0045] The film thickness of the electron transport layers 13 and 23 is not particularly limited and can be appropriately selected according to the purpose. However, 5 nm to 1000 nm is preferred, and 10 nm to 700 nm is more preferred.

[0046] 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 method, 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 using the sol-gel method, 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, letterpress, 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.

[0047] In the case of an inverted structure, after forming the electron transport layer 23, an electron injection layer (hole blocking layer) may be formed between the second electrode 26. Examples of the material used for the electron injection layer include BCP (bathocuproine), and cesium may be doped. The thickness of the electron injection layer is preferably 1 nm to 100 nm, more preferably 3 nm to 20 nm.

[0048] [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 modules such as solar cells. The photoelectric conversion layers 14 and 24 contain, for example, a perovskite compound. The perovskite compound may be, for example, a compound represented by the following chemical formula (I). XαYβZγ (I)

[0049] In the formula (I), the ratio of α:β:γ is, for example, 3:1:1, X represents a halogen ion, Y represents a monovalent cation, and Z represents a divalent cation. The perovskite layer is preferably disposed adjacent to the electron transport layer. Note that the ratio of α:β:γ does not necessarily have to be 3:1:1, for example, it can be 3:1.05:0.95, 3:0.95:1.05. The ratio of α:β:γ is, for example, 3:(0.95 to 1.05):(0.95 to 1.05).

[0050] There is no particular limitation on X in the formula (I), and it can be appropriately selected according to the purpose. For example, halogen ions such as chlorine, bromine, and iodine can be mentioned. These can be used alone or in combination of two or more.

[0051] Examples of Y in the formula (I) include alkylamine compound ions (organic compounds having an amino group) such as methylammonium cation, ethylammonium cation, n-butylammonium cation, formamidinium cation, etc., and not limited to organic ones, alkali metal ions such as cesium cation, potassium cation, rubidium cation, etc. Alkylamine compound ions and alkali metal ions can be used alone or in combination of two or more. Also, an organic (alkylamine compound ion) and an inorganic (alkali metal ion) can be used in combination. For example, cesium ion and formamidine can be used in combination.

[0052] There is no particular limitation on Z in the formula (I), and it can be appropriately selected according to the purpose. For example, divalent metal ions such as lead, indium, antimony, tin, copper, bismuth, germanium, etc. can be mentioned. These can be used alone or in combination of two or more. Particularly, lead is preferred, and among these, the combination of lead and tin is particularly preferred.

[0053] As described above, the photoelectric conversion layers 14 and 24 may be formed of a perovskite compound. The method for forming such a perovskite layer is not particularly limited and can be appropriately selected according to the purpose. For example, a method of applying a solution in which a metal halide and an alkylammonium halide are dissolved or dispersed and then drying it can be mentioned.

[0054] In addition, as a method for forming a perovskite layer, for example, a two-step precipitation method of applying and drying a solution in which a metal halide is dissolved or dispersed, and then immersing it in a solution in which an alkylammonium halide is dissolved to form a perovskite compound can be mentioned.

[0055] Other methods for forming a perovskite layer include, for example, a method of adding a poor solvent (a solvent with low solubility) for the perovskite compound while applying a solution in which a metal halide and an alkylammonium halide are dissolved or dispersed to precipitate crystals. In addition, as a method for forming a perovskite layer, for example, a method of vapor-depositing a metal halide in a gas filled with methylamine or the like can also be mentioned.

[0056] As a method for forming a perovskite layer, a method in which a poor solvent for a perovskite compound is added while applying a solution in which a metal halide and an alkylammonium halide are dissolved or dispersed to precipitate crystals is particularly preferable. There is no particular limitation on the method for applying these solutions, and it can be appropriately selected according to the purpose. For example, dipping method, spin coating method, spraying method, dipping method, roller method, air knife method, etc. can be mentioned. Further, as a method for applying the solution, for example, a method of precipitating in a supercritical fluid using carbon dioxide or the like may be used. As a method for adding the above-mentioned poor solvent to precipitate crystals, examples of the poor solvent used 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.

[0057] As a method for forming a perovskite layer, for example, further, a step (solvent removal step) for the purpose of removing the solvent after forming the perovskite layer, or a step for the purpose of arranging perovskite crystals may be performed. Examples of the solvent removal step and the crystal arrangement step include a method of blowing dry air or the like, a method of heating with a hot plate or an oven, a method of vacuum drying, and the like. As the heating temperature, for example, 50 to 200°C is preferable, and 70 to 180°C is more preferable. As the heating time, for example, 1 to 150 minutes is preferable, and 5 to 60 minutes is more preferable. Further, the thicknesses of the photoelectric conversion layers 14 and 24 are not particularly limited, but from the viewpoint of further suppressing performance deterioration due to defects and peeling, for example, 50 to 1500 nm is preferable, and 200 to 1000 nm is more preferable.

[0058] As a method for forming a perovskite layer, for example, a surface treatment step (surface treatment step) may be included using a salt formed from one or more cations and one or more anions. Examples of the cation include inorganic cations such as lithium, sodium, potassium, rubidium, cesium, magnesium, and calcium; ammonium cation, methylamine, ethylamine, n-butylamine, isopentylamine, neopentylamine, formamidine, acetamidine, benzylamine, 2-phenylethylamine, 2-(4-methoxyphenyl)ethylamine, 4-fluorobenzylamine, 2-(4-fluorophenyl)ethylamine, 1,4-phenylenediamine, 5-aminovaleric acid, melamine, ethylenediamine, p-xylylenediamine, m-xylylenediamine, 1,2-adamantanediamine, 1,3-adamantanediamine, N,N-dimethylethylenediamine, 1,3-diaminopropane, 1,4-diazabicyclo[2.2.2]octane, guanidine, aniline, pyrrole, imidazole, 1-ethylimidazole, 2-ethylimidazole, benzimidazole, morpholine, pyrrolidine, pyrazole, triazole, carbazole and other organic compounds having an amino group; cations obtained from heterocycles containing nitrogen atoms such as pyridine, pyrazine, pyridazine, pyrimidine, quinoline, isoquinoline, phenanthroline, 2,2'-bipyridyl, 4,4'-bipyridyl, etc. Examples of the anion include halogen ions such as fluoride ion, chloride ion, bromide ion, and iodide ion; carboxylate ions such as formate ion and acetate ion; isocyanato ion, thiocyanate ion, tetrafluoroborate ion, hexafluorophosphate ion; trifluoromethanesulfonylimide ion, etc.

[0059] The salt composed of the cation and the anion is preferably dissolved in, for example, one or more solvents. Examples of the solvent 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. The solvent may be used alone or in combination of two or more.

[0060] The surface treatment step is performed by applying and drying a solution in which the salt is dissolved onto the formed perovskite layer. The method for applying the solution is not particularly limited and can be appropriately selected according to the purpose. Examples include dipping method, spin coating method, spraying method, dip method, roller method, air knife method, etc. Further, heat treatment may be performed after coating. When heating, the heating temperature is preferably, for example, 50 to 200 °C, more preferably 70 to 180 °C. The heating time is preferably, for example, 1 to 150 minutes, more preferably 5 to 60 minutes. There is no particular limitation on the film thickness of the solution applied.

[0061] [Second electrodes 16, 26] The second electrodes 16, 26 (which may be, for example, back electrodes) are layers having a function of extracting holes or electrons from the photoelectric conversion layers 14, 24, for example, through a hole transport layer or an electron transport layer.

[0062] The second electrodes 16 and 26 may be formed directly on the hole transport layer 15 in the case of the forward-type structure, or may be formed directly on the electron transport layer 23 in the case of the reverse-type structure. Further, 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. As for the second electrodes 16 and 26, there are no particular restrictions on their shape, structure, and size, and they can be appropriately selected according to the purpose. Examples of the material of the second electrodes 16 and 26 include metals, carbon compounds, conductive metal oxides, and conductive polymers. Examples of the metal include platinum, gold, silver, copper, aluminum, etc. Examples of the carbon compound include graphite, fullerene, carbon nanotube, graphene, etc. Examples of the conductive metal oxide include ITO, IZO, FTO, ATO, etc. Examples of the conductive polymer include polythiophene, polyaniline, etc. Further, the material used for forming the second electrodes 16 and 26 may be used alone or in combination of two or more kinds.

[0063] The second electrodes 16 and 26 can be formed by appropriately using methods such as coating, laminating, vacuum evaporation, CVD, sputtering, bonding, etc. on the hole transport layer 15 or the electron transport layer 23 according to the type of material used and the type of the hole transport layer 15 or the electron transport layer 23.

[0064] In the photoelectric conversion module of the present invention, it is preferable that at least one of the first electrodes 12 or 22 and the second electrodes 16 or 26 is substantially transparent. When using the photoelectric conversion module 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 material that reflects light for the back electrode (the electrode on the side opposite to the transparent electrode, for example, the second electrode), and metals, glass, plastic, or metal thin films with a deposited conductive oxide are preferably used. Further, providing an antireflection layer on the electrode on the incident light side is also an effective means.

[0065] Furthermore, the configuration of the photoelectric conversion module of the present invention is not limited to the configuration of FIG. 1 or FIG. 2. For example, the support 11 may be disposed on the side opposite to FIG. 1 (above the second electrode 16 in FIG. 1), and the second electrode 16, the electron transport layer 15, the photoelectric conversion layer 14, the hole transport layer 13, and the first electrode 12 may be laminated in this order on the support 11. Also, for example, as described above, other components may or may not be present between the support 11, the first electrode 12, the hole transport layer 13, the photoelectric conversion layer 14, the electron transport layer 15, and the second electrode 16. In addition, although an example in which the first electrode 12 is a transparent electrode and the second electrode 16 is a back electrode has been described, the photoelectric conversion module of the present invention is not limited to this. For example, in the photoelectric conversion module of the present invention, conversely, the first electrode may be a back electrode and the second electrode may be a transparent electrode.

[0066] The total thickness of the photoelectric conversion module of the present invention can be appropriately changed according to the thickness of the support used.

[0067] [Sealing] The photoelectric conversion module (for example, a solar cell) of the present invention is preferably sealed in order to protect the device from water and oxygen. The sealing structure is not particularly limited, and for example, it may be the same as that of a general photoelectric conversion module (for example, a solar cell). Specifically, for example, a sealing material may be applied only to the outer peripheral portion of the photoelectric conversion module of the present invention and covered with glass or a film, or a sealing material may be applied to the entire surface of the photoelectric conversion module of the present invention and covered with glass or a film, or only a sealing material may be applied to the entire surface of the photoelectric conversion module of the present invention.

[0068] The material of the sealing member is not particularly limited and can be appropriately selected according to the purpose. For example it is preferable to use an epoxy resin or an acrylic resin and cure it, but it may not be cured or only a part of it may be cured.

[0069] The epoxy resin is not particularly limited, and examples thereof include a water-dispersion type, a solventless type, a solid type, a heat-curable type, a hardener-mixed type, an ultraviolet-curable type, etc. Among these, the heat-curable type and the ultraviolet-curable type are preferred, and the ultraviolet-curable type is more preferred. Note that even in the case of the ultraviolet-curable type, heating is possible, and it is preferable to perform heating even after ultraviolet curing. Specific examples of the epoxy resin include bisphenol A type, bisphenol F type, novolac type, cycloaliphatic type, long-chain aliphatic type, glycidylamine type, glycidyl ether type, glycidyl ester type, etc. These may be used alone or in combination of two or more. Further, it is preferable to mix a hardener and various additives with the epoxy resin as necessary. Epoxy resin compositions that are already commercially available can be used in the present invention. Among them, there are also epoxy resin compositions developed and commercially available for use in solar cells and organic EL elements, and they can be particularly effectively used in the present invention. Examples of commercially available epoxy resin compositions include TB3118, TB3114, TB3124, TB3125F (manufactured by Three Bond Co., Ltd.), WorldRock5910, WorldRock5920, WorldRock8723 (manufactured by Kyoritsu Chemical Industry Co., Ltd.), WB90US(P), WB90US-HV (manufactured by Moresco), etc.

[0070] The acrylic resin is not particularly limited, and for example, those developed and commercially available for use in solar cells and organic EL elements can be effectively used. Examples of commercially available acrylic resin compositions include TB3035B, TB3035C (manufactured by Three Bond Co., Ltd.), etc.

[0071] There are no particular restrictions on the hardener, and it can be appropriately selected according to the purpose. For example, amine-based, acid anhydride-based, polyamide-based, and other hardeners can be mentioned. Examples of amine-based hardeners include aliphatic polyamines such as diethylenetriamine and triethylenetetramine, and aromatic polyamines such as metaphenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone. Examples of acid anhydride-based hardeners include phthalic anhydride, tetra- and hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, pyromellitic anhydride, het anhydride, and dodecenyl succinic anhydride. Examples of other hardeners include imidazoles and polymercaptans. These can be used alone or in combination of two or more.

[0072] There are no particular restrictions on the additive, and it can be appropriately selected according to the purpose. For example, fillers, gap agents, polymerization initiators, desiccants (humectants), curing accelerators, coupling agents, plasticizers, colorants, flame retardant aids, antioxidants, organic solvents, etc. can be mentioned. Among these, fillers, gap agents, curing accelerators, polymerization initiators, and desiccants (humectants) are preferred, and fillers and polymerization initiators are more preferred. By containing a filler as an additive, the ingress of moisture and oxygen can be suppressed, and furthermore, effects such as reduction of volume shrinkage during curing, reduction of outgassing amount during curing or heating, improvement of mechanical strength, and control of thermal conductivity and fluidity can be obtained. Therefore, including a filler as an additive is very effective for maintaining stable output in various environments.

[0073] In addition, regarding the output characteristics and durability of the photoelectric conversion module, not only the influence of the invading moisture and oxygen but also the influence of outgassing generated during the curing or heating of the sealing member cannot be ignored. In particular, the influence of outgassing generated during heating has a great impact on the output characteristics during storage in a high-temperature environment. By incorporating a filler, a gap filler, and a desiccant into the sealing member, these can not only suppress the intrusion of moisture and oxygen themselves, but also reduce the amount of the sealing member used, thereby obtaining the effect of reducing outgassing. Incorporating a filler, a gap filler, and a desiccant into the sealing member is effective not only during curing but also when storing the photoelectric conversion module in a high-temperature environment.

[0074] There are no particular restrictions on the filler, and it can be appropriately selected according to the purpose. For example, crystalline or amorphous silica, silicate minerals such as talc, inorganic fillers such as alumina, aluminum nitride, silicon nitride, calcium silicate, and calcium carbonate can be mentioned. Among these, hydrotalcite is particularly preferred. Also, these can be used alone or in combination of two or more.

[0075] 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, the adhesion to the substrate and the defoaming property are improved, and it is also effective for controlling the width of the sealing portion and workability.

[0076] The content of the filler is preferably 10 parts by mass or more and 90 parts by mass or less, and more preferably 20 parts by mass or more and 70 parts by mass or less with respect to the entire sealing member (100 parts by mass). When the content 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 is also appropriate, and the adhesion and workability are also good.

[0077] The gap agent is also referred to as a gap control agent or a spacer agent. By including a gap material as an additive, it becomes possible to control the gap of the sealing portion. For example, when a sealing member is provided on a first substrate or a first electrode, and a second substrate is placed thereon for sealing, since the sealing member is mixed with the gap agent, the gap of the sealing portion is aligned with the size of the gap agent, so that the gap of the sealing portion can be easily controlled.

[0078] The gap agent is not particularly limited. For example, those that are granular and have a uniform particle size, and high solvent resistance and heat resistance are preferable, and can be appropriately selected according to the purpose. As the gap agent, those having high affinity with the epoxy resin and a spherical particle shape are preferable. Specifically, glass beads, silica fine particles, organic resin fine particles, etc. are preferable. These may be used alone or in combination of two or more. The particle size of the gap agent can be selected according to the gap of the sealing portion to be set, but is preferably 1 μm or more and 100 μm or less, and more preferably 5 μm or more and 50 μm or less.

[0079] The polymerization initiator is not particularly limited. For example, polymerization initiators that initiate polymerization using heat or light can be mentioned, and can be appropriately selected according to the purpose. For example, thermal polymerization initiators, photoinitiators, etc. can be mentioned. A thermal polymerization initiator is a compound that generates active species such as radicals or cations by heating, and examples include azo compounds such as 2,2'-azobisbutyronitrile (AIBN) and peroxides such as benzoyl peroxide (BPO). As the thermal cationic polymerization initiator, benzenesulfonic acid esters, alkylsulfonium salts, etc. are used. In the case of an epoxy resin, a photo cationic polymerization initiator is preferably used as the photoinitiator. When a photo cationic polymerization initiator is mixed with an epoxy resin and light irradiation is performed, the photo cationic polymerization initiator decomposes to generate an acid, and the acid causes the polymerization of the epoxy resin, and the curing reaction proceeds. The photo cationic polymerization initiator has effects such as less volume shrinkage during curing, no oxygen inhibition, and high storage stability.

[0080] Examples of the photo cationic polymerization initiator include aromatic diazonium salts, aromatic iodonium salts, aromatic sulfonium salts, metacelone compounds, silanol-aluminum complexes, etc. Further, as the polymerization initiator, a photoacid generator having a function of generating an acid by irradiating light can also be used. The photoacid generator acts as an acid that initiates cationic polymerization, and examples thereof include onium salts such as ionic sulfonium salt-based and iodonium salt-based compounds composed of a cationic part and an anionic part. These may be used alone or in combination of two or more kinds.

[0081] The addition amount of the polymerization initiator is not particularly limited and may vary depending on the materials used. However, it is preferably 0.5 parts by mass or more and 10 parts by mass or less, more preferably 1 part by mass or more and 5 parts by mass or less, based on the entire sealing member (100 parts by mass). When the addition amount is within the above preferred range, curing proceeds appropriately, the residual amount of the uncured material can be reduced, and the generation of excessive outgas can be prevented.

[0082] The desiccant (also referred to as a moisture absorbent) is a material having a function of physically or chemically adsorbing and absorbing moisture. By incorporating it into the sealing member, the moisture resistance can be further enhanced and the influence of outgas can be reduced. There is no particular limitation on the desiccant, and it can be appropriately selected according to the purpose. However, those in a particulate form are preferred. Examples thereof include inorganic water-absorbing materials such as calcium oxide, barium oxide, magnesium oxide, magnesium sulfate, sodium sulfate, calcium chloride, silica gel, molecular sieve, and zeolite. Among these, zeolite having a large moisture absorption amount is preferred. These may be used alone or in combination of two or more kinds.

[0083] The above-mentioned curing accelerator (also referred to as a curing catalyst) is a material that accelerates the curing rate and is mainly used for thermosetting epoxy resins. There are no particular restrictions on the above-mentioned curing accelerator, and it can be appropriately selected according to the purpose. For example, 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), imidazole-based ones such as 1-cyanoethyl-2-ethyl-4-methylimidazole and 2-ethyl-4-methylimidazole, phosphines or phosphonium salts such as triphenylphosphine and tetraphenylphosphonium·tetraphenylborate, etc. can be mentioned. These may be used alone or in combination of two or more kinds.

[0084] The above-mentioned coupling agent is not particularly limited as long as it is a material having the effect of enhancing the molecular bonding force, and it can be appropriately selected according to the purpose. For example, silane coupling agents can be mentioned. Specifically, 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, 3-methacryloxypropyltrimethoxysilane and other silane coupling agents can be mentioned. These may be used alone or in combination of two or more kinds.

[0085] In the present invention, for example, a sheet-like adhesive can be used. The sheet-like adhesive is, for example, one in which a resin layer is previously formed on a sheet, and glass, a film having high gas barrier properties, or the like can be used for the sheet. Also, a sheet may be formed only of a sealing resin. It is also possible to attach the sheet-like adhesive onto a sealing film. It is also possible to form a structure having a hollow portion on the sealing film and then bond it to the device.

[0086] When sealing using the sealing film, it is disposed to face a support so as to sandwich the photoelectric conversion device. Regarding the base material of the sealing film, there are no particular restrictions on its shape, structure, size, or type, and it can be appropriately selected according to the purpose. The sealing film has a barrier layer formed on the surface of the base material to prevent the passage of moisture and oxygen, and the barrier layer may be formed on only one surface or both surfaces of the base material.

[0087] The barrier layer may be composed of a material mainly composed of, for example, a metal oxide, a metal, a mixture formed from a polymer and a metal alkoxide, or the like. Examples of the metal oxide include aluminum oxide, silicon oxide, aluminum, etc., examples of the polymer include polyvinyl alcohol, polyvinyl pyrrolidone, methyl cellulose, etc., and examples of the metal alkoxide include tetraethoxysilane, triisopropoxyaluminum, 3-glycidoxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, etc.

[0088] The barrier layer may be, for example, transparent or opaque. Also, the barrier layer may be a single layer formed by a combination of the above materials or a plurality of laminated structures. As a method for forming the barrier layer, a known method can be used, and a vacuum film forming method such as a sputtering method, a coating method such as a dipping method, a roll coating method, a screen printing method, a spraying method, a gravure printing method, etc. can be used.

[0089] [Wiring] In order to efficiently extract the current generated by light, it is preferable to connect lead wires (wiring) to the electrodes and the back electrode of the photoelectric conversion module (for example, a 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 mixed or laminated structure of two or more kinds. Further, the portion where the lead wire is attached may be covered with an acrylic resin or an epoxy resin from the viewpoint of physical protection.

[0090] A lead wire is a general term for electric wires for electrically connecting power sources, electronic components, etc. in an electric circuit, and examples thereof include vinyl wires and enameled wires.

[0091] [Application] The use and method of use of the photoelectric conversion module of the present invention are not particularly limited, and for example, it can be widely used for the same applications as general photoelectric conversion modules (for example, general solar cells). The photoelectric conversion module (for example, a solar cell) of the present invention can be applied to a power supply device by combining it with a circuit board that controls the generated current, etc. Examples of devices using the power supply device include electronic desktop calculators and solar radio watches. In addition, it is also possible to apply the photoelectric conversion module of the present invention as a power supply device to mobile phones, electronic paper, thermohygrometers, etc. Further, it can also be applied for auxiliary power sources to extend the continuous use time of rechargeable or dry battery-powered electrical appliances, or for night use by combining it with a secondary battery. It can also be used as a self-sufficient power source that does not require battery replacement or power wiring.

Example

[0092] Hereinafter, examples of the present invention will be described. However, the present invention is not limited to the following examples.

[0093] In the following examples, the yield (%) is the yield (mol%) based on the amount of substance (mol), unless otherwise specified. The NMR (nuclear magnetic resonance) spectrum was measured using AV400M (trade name) manufactured by Bruker Corporation.

[0094] [Synthesis Example 1: Synthesis of A-56] 9-Bromotriptycene (333 mg, 1.00 mmol) was dissolved in diethyl ether, and n-butyllithium (1.10 mL, 1.76 mmol hexane solution) was slowly added at room temperature. After dropping, the mixture was stirred for 1 hour. Then, the supernatant was removed and washed twice with n-hexane. To the obtained THF suspension (10 mL) of 9-triptysilyllithium, a 2 tetrahydrofuran solution of SnCl 1 -dioxane complex (278 mg, 1.00 mmol) was added at -78 °C. While stirring, the temperature of the reaction solution was gradually returned to room temperature, and the suspension was filtered. The obtained colorless crystals were dissolved in toluene, and the filtered solution was concentrated under reduced pressure. The residue was washed several times with n-hexane to obtain A-56 (156 mg, 0.0767 mmol) as yellow crystals. The yield was 38.4%. The 8 1H-NMR chart (toluene-d 119 ) is shown in Figure 3. Also, the 8 119Sn-NMR chart (toluene-d

[0095] [Synthesis Example 2: Synthesis of A-57] 9-Bromotriptycene (167 mg, 0.501 mmol) was dissolved in diethyl ether, and n-butyllithium (0.45 mL, 0.72 mmol hexane solution) was slowly added at room temperature. After dropping, the mixture was stirred for 1 hour. Then, the supernatant was removed and washed twice with n-hexane. To the obtained THF suspension (10 mL) of 9-triptysilyllithium, SnBr 2A solution of (139 mg, 0.499 mmol) in tetrahydrofuran was added at -78 °C. While stirring, the temperature of the reaction solution was gradually returned to room temperature, and the suspension was filtered. The obtained colorless crystals were dissolved in toluene, and the filtered solution was concentrated under reduced pressure. The residue was washed several times with n-hexane to obtain A-57 (40.8 mg, 0.018 mmol) as yellow crystals. The yield was 3.6%. The 1 1H-NMR chart (benzene-d 6 ) is shown in Figure 5. Also, the 119 119Sn-NMR chart (benzene-d 6 ) is shown in Figure 6.

[0096] [Synthesis Example 3: Synthesis of A-37] 9-Bromotriptycene (167 mg, 0.501 mmol) was dissolved in tetrahydrofuran, and n-butyllithium (0.33 mL, 0.53 mmol hexane solution) was slowly added at room temperature. After dropping, stirring was carried out for 1 hour. Then, the supernatant was removed and washed twice with n-hexane. To the obtained THF suspension (10 mL) of 9-triptysilyllithium, a solution of SbI 2 (377 mg, 0.750 mmol) in tetrahydrofuran was added at -78 °C. While stirring, the temperature of the reaction solution was gradually returned to room temperature. The solution was concentrated under reduced pressure. The residue was dissolved in toluene and n-hexane, and the impurities were removed by filtration. The solution was concentrated under reduced pressure, and the residue was purified by recrystallization. Orange crystals of A-37 were obtained.

[0097] [Synthesis Example 4: Synthesis of A-2] 9-Bromotriptycene (999 mg, 3.00 mmol) was dissolved in diethyl ether, and n-butyllithium (4.0 mL, 6.4 mmol hexane solution) was slowly added at room temperature. After the addition dropwise, stirring was carried out for 1 hour. Next, dry ice was added and stirring was continued overnight. Hydrochloric acid was added to the reaction solution to stop the reaction, and extraction was performed with diethyl ether. The organic layer was washed with water and concentrated under reduced pressure. The residue was washed with chloroform to obtain colorless crystalline 9-triptycylcarboxylic acid. This 9-triptycylcarboxylic acid (246 mg, 0.897 mmol) was dissolved in ethanol, and an ethanol solution of methylamine (1.0 mL, 2.0 mmol) was added, and stirring was carried out overnight at room temperature. n-Hexane was added to the reaction solution to obtain colorless crystalline A-2 (228 mg, 0.746 mmol). The yield was 83.1%. The 1 1H-NMR chart (DMSO-d 6 ) is shown in Figure 7.

[0098] [Example 1] A solar cell, which is a photoelectric conversion element of the present invention, was fabricated (manufactured) as follows.

[0099] A 3PATAT-C3 DMF solution (0.1 mmol / L) shown below was placed in an amount of 100 μL on ITO of an ITO glass substrate (a glass substrate as a support with a first electrode formed thereon), and a monomolecular layer (hole transport layer) was formed on the ITO (first electrode) using a spin coater (3,000 rpm, 30 seconds). Next, a solution prepared by dissolving cesium iodide (0.738 g), formamidinium iodide (7.512 g), methylammonium bromide (0.905 g), lead iodide (23.888 g), and lead bromide (1.022 g) in DMF (40.0 mL) and dimethyl sulfoxide (DMSO, 12.0 mL) was formed into a film on the above substrate using spin coating. For spin coating, it was 3,000 rpm, and chlorobenzene (0.3 mL) was dropped 30 seconds after the start. Then, it was heated at 150 °C for 10 minutes to obtain a perovskite layer (photoelectric conversion layer). On this, a toluene solution (1.0 mL) in which A-56 (0.5 mg) was dissolved was placed in an amount of 120 μL on the above substrate and formed into a film using spin coating (4,000 rpm, 30 seconds). After film formation, it was heated at 120 °C for 10 minutes. Next, C60 was 20 nm (electron transport layer), bathocuproine (BCP, 8 nm) (electron injection layer), and Ag (100 nm) (second electrode) were formed into films by vacuum evaporation to fabricate a photoelectric conversion element.

[0100] [Chemical formula]

[0101] The photovoltaic conversion characteristics of the encapsulated device fabricated in Example 1 were measured by a method compliant with the output measurement method for silicon crystalline solar cells of JIS C8913:1998. Using a solar simulator (SMO-250III type manufactured by Spectral Instruments Co., Ltd.) combined with an air mass filter equivalent to AM1.5G, adjusted to a light intensity of 100 mW / cm2 with a secondary standard Si solar cell as the light source for measurement, while irradiating light on a test sample of the perovskite solar cell (the encapsulated device fabricated in Example 1), the I-V curve characteristics were measured using a source meter (Model 2400 universal source meter manufactured by Keithley Instruments Inc.). The short-circuit current (Isc), open-circuit voltage (Voc), fill factor (FF), short-circuit current density (Jsc), and photovoltaic conversion efficiency (PCE) obtained from the I-V curve characteristics were calculated using the following Equations 1 and 2. The results are shown in Table 1 below.

[0102] Equation 1: Short-circuit current density (Jsc; mA / cm 2 ) = Isc (mA) / effective light-receiving area S (cm 2 ) Equation 2: Photovoltaic conversion efficiency (PCE; %) = Voc (V) × Jsc (mA / cm 2 ) × FF × 100 / 100 (mW / cm 2 )

[0103] A photovoltaic device was fabricated and evaluated in the same manner as in Example 1, except that the toluene solution (1.0 mL) in which A-56 (0.5 mg) was dissolved in Example 1 was changed to a toluene solution (1.0 mL) in which A-57 (0.5 mg) was dissolved. The results are shown in Table 1.

[0104] [Example 3] A photovoltaic device was fabricated and evaluated in the same manner as in Example 1, except that the toluene solution (1.0 mL) in which A-56 (0.5 mg) was dissolved in Example 1 was changed to a toluene solution (1.0 mL) in which A-37 (0.5 mg) was dissolved. The results are shown in Table 1.

[0105] [Example 4] A photoelectric conversion device was fabricated and evaluated in the same manner as in Example 1, except that the toluene solution (1.0 mL) in which A-56 (0.5 mg) was dissolved was changed to a toluene solution (1.0 mL) in which A-2 (0.5 mg) was dissolved. The results are shown in Table 1.

[0106] [Example 5] On the ITO of an ITO glass substrate (a glass substrate as a support with a first electrode formed thereon), 320 μL of a solution obtained by diluting an aqueous dispersion of tin oxide fine particles (Alfa Aesar 44592) with pure water twice and filtering it through a PTFE filter was placed, and an electron transport layer was formed on the ITO (first electrode) using a spin coater (3,000 rpm, 30 seconds). Next, a solution in which cesium iodide (0.738 g), formamidinium iodide (7.512 g), methylammonium bromide (0.905 g), lead iodide (23.888 g), and lead bromide (1.022 g) were dissolved in DMF (40.0 mL) and dimethyl sulfoxide (DMSO, 12.0 mL) was spin-coated on the above substrate. For spin coating, it was 3000 rpm, and chlorobenzene (0.3 mL) was dropped 30 seconds after the start. Then, it was heated at 150 °C for 10 minutes to obtain a perovskite layer (photoelectric conversion layer). On this, 120 μL of a toluene solution (1.0 mL) in which A-56 (0.5 mg) was dissolved was placed on the above substrate and spin-coated (4,000 rpm, 30 seconds) to form a film. After film formation, it was heated at 120 °C for 10 minutes. Next, 100 μL of a solution in which Spiro-OMeTAD (72.3 mg), [tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine)cobalt(III)tris(bis(trifluoromethylsulfonyl)imide)] (FK209) (13.3 mg), 4-t-butylpyridine (28.8 μL), and lithium bis(trifluoromethylsulfonyl)imide (7.6 mg) were dissolved in chlorobenzene (1 mL) was placed on the above substrate, and an electron transport layer was formed on the ITO (first electrode) using a spin coater (3,000 rpm, 30 seconds). Finally, an 80-nm gold electrode was provided by vacuum evaporation to fabricate a photoelectric conversion device. The obtained photoelectric conversion device was evaluated for photoelectric conversion characteristics in the same manner as in Example 1. The results are shown in Table 1.

[0107] [Comparative Example 1] A photoelectric conversion device was fabricated and evaluated in the same manner as in Example 1, except that the toluene solution (1.0 mL) in which A-56 (0.5 mg) was dissolved in Example 1 was changed to a 2-propanol solution (1.0 mL) in which phenylethylamine (0.5 mg) was dissolved. The results are shown in Table 1.

[0108] [Comparative Example 2] A photoelectric conversion device was fabricated and evaluated in the same manner as in Example 1, except that the toluene solution (1.0 mL) in which A-56 (0.5 mg) was dissolved in Example 5 was changed to a 2-propanol solution (1.0 mL) in which phenylethylamine (0.5 mg) was dissolved. The results are shown in Table 1.

[0109] [Table 1]

[0110] As described above, it was confirmed by this example that a high-performance and highly durable photoelectric conversion device can be obtained by forming a film of the bicyclic compound of the present invention at the interface between the photoelectric conversion layer (14) and the hole transport layer (15) or by using it for the photoelectric conversion layer (24) and the electron transport layer (25).

[0111] 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, changed, or selected and adopted within the scope not departing from the gist of the present invention.

[0112] The present invention can be represented, for example, as follows in the following supplementary notes, but is not limited thereto. [Supplementary Note 1] A photoelectric conversion device containing a bicyclic compound represented by the following general formula (I), a tautomer or stereoisomer thereof, or a salt thereof. [Chemical Formula] In the general formula (I), Z 1 and Z 2 may be the same as or different from each other, and each represents C-R or a nitrogen atom, provided that C is a carbon atom and R is a hydrogen atom or a substituent. X 1 、X 2 、and X 3 may be the same as or different from each other, and each represents a divalent linking group that forms a cyclic structure together with the central bicyclic ring. In the central bicyclic ring, the bond between two carbon atoms common to the two rings may be a single bond or a double bond. (Appendix 2) The compound represented by the general formula (I) is a photoelectric conversion element described in Appendix 1 represented by the following general formula (II). [Chemical formula] In the general formula (II), R 1 、and R 2 may be the same as or different from each other, and each represents hydrogen, an alkyl group, an alkoxy group, an aryl group, a heteroaryl group, a carboxy group, an ester group, an amino group, a halogen atom, or a metal halide, provided that at least one of them is not hydrogen. One or more hydrogens of the alkyl group, the alkoxy group, the aryl group, the heteroaryl group, and the amino group may or may not be substituted by a substituent. The carboxy group may have a negative charge, and the amino group may have a positive charge. X 1 、X 2 、and X 3 may be the same as or different from each other, and each represents a divalent linking group that forms a cyclic structure. (Appendix 3) The compound represented by the general formula (I) is a photoelectric conversion element described in Appendix 1 or 2 represented by the following general formula (III). [Chemical formula] In the general formula (III), R 1 、and R2 may be the same as or different from each other, and each represents hydrogen, an alkyl group, an alkoxy group, an aryl group, a halogen atom, a tin halide, a lead halide, an antimony halide, or a bismuth halide, provided that at least one of them is not hydrogen, each R 3 may be the same as or different from each other, and each represents hydrogen, an alkyl group, an alkoxy group, an aryl group, or a halogen atom. (Appendix 4) The compound represented by the general formula (I) is a photoelectric conversion element according to any one of Appendices 1 to 3 represented by the following general formula (IV). [Chemical formula] In the general formula (IV), R 1 represents a tin halide, a lead halide, an antimony halide, or a bismuth halide. (Appendix 5) The first electrode, the hole transport layer, the photoelectric conversion layer, the electron transport layer, and the second electrode are directly or indirectly laminated in this order, the photoelectric conversion layer contains a perovskite compound, and the photoelectric conversion element according to Appendix 1 containing the bicyclic compound represented by the general formula (I) on the main surface of the photoelectric conversion layer at the interface between the photoelectric conversion layer and the electron transport layer. (Appendix 6) A compound represented by any one of the chemical formulas (I), (II), (III), (IV) and A-1 to A-60, a tautomer or stereoisomer thereof, or a salt thereof. [Industrial Applicability]

[0113] As described above, according to the present invention, a photoelectric conversion device exhibiting excellent photoelectric conversion characteristics can be provided by using a bicyclic compound. The photoelectric conversion device of the present invention is useful, for example, as a solar cell. The uses and usage methods of the photoelectric conversion device of the present invention are not particularly limited, and it can be applied to a wide range of fields in the same uses and usage methods as general photoelectric conversion devices (for example, general solar cells). Further, the compound of the present invention can exhibit excellent photoelectric conversion characteristics and obtain a photoelectric conversion device having high durability by being used, for example, in the hole transport layer of the photoelectric conversion device of the present invention. However, the uses and usage methods of the compound of the present invention are not limited thereto, and it can be applied to any wide range of fields.

Explanation of Symbols

[0114] 10 Photoelectric conversion device 11 Support 12 First electrode 13 Electron transport layer 14 Photoelectric conversion layer 15 Hole transport layer 16 Second electrode 20 Photoelectric conversion device 21 Support 22 First electrode 23 Electron transport layer 24 Photoelectric conversion layer 25 Hole transport layer 26 Second electrode

Claims

1. A photoelectric conversion element containing a bicyclic compound represented by the following general formula (I), a tautomer or stereoisomer thereof, or a salt thereof. 【Chemical I】 In the general formula (I), Z １ and Z ２ may be the same as or different from each other, and each represents C—R or a nitrogen atom, provided that C is a carbon atom and R is a hydrogen atom or a substituent, X １ , X ２ , and X ３ may be the same as or different from each other, and each represents a divalent linking group that forms a cyclic structure together with the central bicyclic ring. In the central bicyclic ring, the bond between two carbon atoms common to the two rings may be a single bond or a double bond.

2. The photoelectric conversion element according to Claim 1, wherein the compound represented by the general formula (I) is represented by the following general formula (II). [Chemical II] In the general formula (II), R 1 , and R 2 may be the same as or different from each other, and each represents hydrogen, an alkyl group, an alkoxy group, an aryl group, a heteroaryl group, a carboxy group, an ester group, an amino group, a halogen atom, or a metal halide, provided that at least one of them is not hydrogen. One or more hydrogens of the alkyl group, the alkoxy group, the aryl group, the heteroaryl group, and the amino group may or may not be substituted by a substituent. The carboxy group may have a negative charge, and the amino group may have a positive charge. X １ 、 X ２ 、 and X ３ may be the same as or different from each other, and each represents a divalent linking group that forms a cyclic structure.

3. The photoelectric conversion element according to Claim 1, wherein the compound represented by the general formula (I) is represented by the following general formula (III). 【Chemical III】 In the general formula (III), R 1 , and R 2 may be the same as or different from each other, and each represents hydrogen, an alkyl group, an alkoxy group, an aryl group, a halogen atom, a tin halide, a lead halide, an antimony halide, or a bismuth halide, provided that at least one of them is not hydrogen, Each R 3 may be the same as or different from each other, and each represents a hydrogen, alkyl group, alkoxy group, aryl group, or halogen atom.

4. The photoelectric conversion element according to Claim 1, wherein the compound represented by the general formula (I) is represented by the following general formula (IV). 【Chemical IV】 In the general formula (IV), R 1 represents tin halide, lead halide, antimony halide, or bismuth halide.

5. A first electrode, a hole transport layer, a photoelectric conversion layer, an electron transport layer, and a second electrode are directly or indirectly laminated in this order, the photoelectric conversion layer contains a perovskite compound, and the photoelectric conversion layer, or the main surface of the photoelectric conversion layer at the interface between the photoelectric conversion layer and the electron transport layer contains the bicyclic compound represented by the general formula (I). The photoelectric conversion element according to Claim 1.

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