Photoelectric conversion element and solar cell module

Abstract

The purpose of the present invention is to provide a photoelectric conversion element exhibiting excellent photoelectric conversion characteristics and having little fluctuation. A photoelectric conversion element (10) according to one embodiment of the present invention has a structure in which a first electrode (12), a hole transport layer (13), a photoelectric conversion layer (14), an electron transport layer (15), and a second electrode (16) are laminated in this order. The photoelectric conversion layer (14) contains a perovskite compound. The hole transport layer (13) contains an insulating compound and a monomolecular hole transport material. The hole transport material contains a compound represented by chemical formula (I). Ar1-(L1-X1) n (I) In the chemical formula (I), Ar1 is a structure including an aromatic ring, heteroatoms may be included in the atoms constituting the aromatic ring, and Ar1 may have a substituent other than-L1-X1. And n is an integer of 1 or more, and when n is 2 or more, the structures represented by-L1-X1 may be the same as or different from each other. And L1 is a single bond or a divalent linking group that bonds Ar1 to X1. X1 is a group capable of forming a chemical bond or a hydrogen bond with a p-type metal oxide semiconductor.

Description

Technical Field

[0001] This invention relates to a photoelectric conversion element and a solar cell module. Background Technology

[0002] In recent years, solar power generation, as a clean energy source, has received much attention, and the development of solar cells is constantly advancing. Among these, 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 Literature 1 reports a solution-type solar cell using perovskite materials as the light-absorbing layer. Furthermore, Non-Patent Literature 2 also reports a solid-state perovskite solar cell exhibiting high efficiency.

[0003] As a basic structure for perovskite solar cells, known structures include a conformal structure in which an electron transport layer, a light absorption layer (perovskite layer), a hole transport layer (also called an electron hole transport layer), and a back electrode are sequentially stacked on the electrodes; and an inverted structure in which a hole transport layer, a light absorption layer, an electron transport layer, and a back electrode are sequentially stacked on the electrodes. Sometimes, an electron transport layer with a porous shape is included between the electron transport layer and the perovskite layer. The hole transport layer typically uses a hole-transporting material of organic semiconductor (e.g., Non-Patent Documents 3 to 10).

[0004] Existing technical documents

[0005] Non-patent literature

[0006] Non-patent literature 1: Journal of the American Chemical Society, 2009, 131, 6050-6051.

[0007] Non-patent literature 2: Science, 2012, 388, 643-647.

[0008] Non-patent literature 3: ACS Appl. Mater. Interfaces, 2017, 9, 24778-24787.

[0009] Non-patent literature 4: Energy and Environmental Science, 2014, 7, 1454-1460.

[0010] Non-patent literature 5: Journal of Materials Chemistry (J. Mater. Chem.) A, 2014, 2, 6305-6309.

[0011] Non-patent literature 6: Journal of Materials Chemistry (J. Mater. Chem.) A, 2015, 3, 12139-12144.

[0012] Non-patent literature 7: Journal of Materials Chemistry (J. Mater. Chem.) A, 2018, 6, 7950-7958.

[0013] Non-patent literature 8: ACS Appl. Mater. Interfaces, 2015, 7, 11107-11116.

[0014] Non-patent literature 9: Energy & Environmental Science, 2014, 7, 2963-2967.

[0015] Non-patent literature 10: Advanced Energy Materials, 2018, 8, 1801-1892. Summary of the Invention

[0016] The problem that the invention aims to solve

[0017] However, the photoelectric conversion efficiency of traditional perovskite solar cells is not satisfactory. Improving the photoelectric conversion efficiency of solar cells is particularly important, especially in enhancing the characteristics of the hole transport layer. As hole transport materials for the hole transport layer, compounds such as truxene (Non-Patent Document 3), diketopyrrolopyrrole (Non-Patent Document 4), thiophene compounds (Non-Patent Documents 5 and 6), and dithienopyrrole (Non-Patent Document 7) have been reported to date. However, almost no compounds have been reported that achieve a photoelectric conversion efficiency sufficient to be considered useful for perovskite solar cells. Therefore, [2,2',7,7'-tetrakis(N,N-di-p-methoxyphenylamino)-9,9'-spirobifluorene] (Spiro-OMeTAD) was proposed as a hole transport material for pigment-sensitized solar cells, but it is known to have low heat resistance (Non-Patent Literature 8). Additionally, polymer materials with a triphenylamine backbone, known as PTAA (poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]), also have low light resistance. Furthermore, when these materials are used as hole transport materials for p-buffer layers, bis(trifluoromethanesulfonyl)imidelithium (LiTFSI) salts need to be added as additives to improve conductivity, which is considered to be one of the causes of device degradation (Non-Patent Document 9). In addition, carbazole-type hole transport materials containing phosphonic acids have been reported in recent years (Non-Patent Document 10). These compounds react with indium tin oxide (ITO) compounds used as transparent electrodes to form a monolayer on the transparent electrode. Regarding these hole transport compounds that form monolayers, photoelectric conversion efficiencies exceeding 20% ​​have been reported, making them excellent compounds. However, if the hole transport layer does not adequately cover the electrode, contact between the electrode and the photoelectric conversion layer occurs, leading to a decrease in photoelectric conversion characteristics and sometimes insufficient durability.

[0018] Therefore, the object of the present invention is to provide a photoelectric conversion element and a solar cell module that exhibit excellent photoelectric conversion characteristics with minimal characteristic fluctuations.

[0019] Technical means to solve the problem

[0020] One embodiment of the present invention is a photoelectric conversion element. In the photoelectric conversion element, a first electrode, a hole transport layer, a photoelectric conversion layer, an electron transport layer, and a second electrode are stacked directly or indirectly in this order. The photoelectric conversion layer comprises a perovskite compound, and the hole transport layer comprises an insulating compound in contact with the main surface of the first electrode on the side of the photoelectric conversion layer, as well as a compound represented by the following chemical formula (I).

[0021] Ar 1 -(L 1 -X 1 (I)

[0022] In the chemical formula (I), Ar 1 For a structure containing an aromatic ring, heteroatoms may be included among the atoms constituting the aromatic ring, Ar 1 It can have the function of -L 1 -X 1 Other substituents. For integers n greater than or equal to 1, -L is used when n is 2 or greater. 1 -X 1 The structures represented can be the same or different from each other. L 1 To make Ar 1 With X 1 A binary linker or a single bond. X 1 It is a group that can form chemical bonds or hydrogen bonds with the first electrode.

[0023] In the photoelectric conversion element of the embodiment, the hole transport layer may contain a compound represented by the following chemical formula (II).

[0024] A 1 -L 2 -X 2 ... (II)

[0025] A 1A group of atoms comprising one or more substituents or structures selected from the group consisting of alkoxy, hydroxy, carboxyl, dihydroxyphosphoryl, dialkylphosphoryl, hydroxysulfonyl, amino, monoalkylamino, dialkylamino, monoarylamino, diarylamino, monoalkylaminocarbonyl, dialkylaminocarbonyl, alkylcarbonyloxy, alkoxycarbonyl, aminocarbonyl, aminocarbonylamino, alkylcarbonylamino, alkylsulfonylamino, aminosulfonyl, and nitrogen-containing heterocyclic groups. 2 To make A 1 With X 2 A binary linker or a single bond. X 2 It is a group that can form chemical bonds or hydrogen bonds with the first electrode.

[0026] The compound represented by the chemical formula (I) can form a monolayer.

[0027] The insulating compound may be selected from at least one of metal oxides, metal nitrides, insulating organic compounds, and organic-inorganic hybrid compounds.

[0028] The insulating compound may be in particle shape. In this case, the average particle size of the insulating compound may be in the range of 1 nm to 200 nm.

[0029] X in the chemical formula (I) 1It can be selected from the group consisting of dihydroxyphosphoryl (-P=O(OH)2), carboxyl (-COOH), sulfonyl (-SO3H), borate (-B(OH)2), trihalosilyl (-SiX3, where X is a halogenated group), trialkoxysilyl (-Si(OR)3, where R is an alkyl group), trihydroxysilyl, and dialkylphosphoryl.

[0030] X in chemical formula (II) 2 It can be independently selected from the group consisting of dihydroxyphosphoryl (-P=O(OH)2), carboxyl (-COOH), sulfonyl (-SO3H), borate (-B(OH)2), trihalosilyl (-SiX3, where X is a halogenated group), trialkoxysilyl (-Si(OR)3, where R is an alkyl group), trihydroxysilyl, and dialkylphosphoryl.

[0031] The perovskite compound may be an organic or inorganic perovskite compound.

[0032] The mass ratio of the compound represented by the chemical formula (I) to the mass of the insulating compound (m2) can satisfy the following relationship (A).

[0033] m1 / m2 = 1 / 10 ~ 1 / 20000 (A)

[0034] An intermediate layer containing nickel oxide may be formed between the first electrode and the hole transport layer.

[0035] Another embodiment of the present invention is a solar cell module. The solar cell module includes the photoelectric conversion element of any of the above embodiments.

[0036] The effects of the invention

[0037] The present invention provides a photoelectric conversion element that exhibits excellent photoelectric conversion characteristics and suppresses characteristic fluctuations. Attached Figure Description

[0038] [ Figure 1 ] Figure 1 This is a cross-sectional view showing an example of the structure of the photoelectric conversion element according to an embodiment.

[0039] [ Figure 2 ] Figure 2 This is a plan view illustrating the manufacturing process of a solar cell module according to an embodiment.

[0040] [ Figure 3 ] Figure 3 This is a plan view illustrating the manufacturing process of a solar cell module according to an embodiment.

[0041] [ Figure 4 ] Figure 4 This is a plan view illustrating the manufacturing process of a solar cell module according to an embodiment.

[0042] [ Figure 5 ] Figure 5 It is along Figure 4 A cross-sectional view of line A-A'. Detailed Implementation

[0043] Examples will be given to illustrate the invention in more detail. However, the invention is not limited to the following description. Furthermore, the following description addresses the case where the photoelectric conversion element in the embodiment is a solar cell.

[0044] [Photoelectric conversion element]

[0045] Figure 1 This is a cross-sectional view showing an example of the structure of the photoelectric conversion element 10 according to an embodiment. Furthermore, Figure 1 For ease of explanation, appropriate omissions, exaggerations, etc., are used in the illustration. For example... Figure 1 As shown, the photoelectric conversion element 10 has a stacked structure formed by sequentially stacking a first electrode 12, a hole transport layer 13, a photoelectric conversion layer 14, an electron transport layer 15, and a second electrode 16 on a support (also called a substrate, base material, etc.) 11. Furthermore, in this embodiment, as... Figure 1 The diagram shows an electron transport layer 15, but this layer can be arbitrary. As long as the desired photoelectric conversion characteristics are achieved, the photoelectric conversion layer 14 and the second electrode 16 can also be connected. In other words, the first electrode 12, hole transport layer 13, photoelectric conversion layer 14, and second electrode 16 can be stacked directly or indirectly in this order. Except... Figure 1 In addition to the layers shown, for example, an interface layer may be disposed between the photoelectric conversion layer 14 and the electron transport layer 15, and an electron injection layer may be disposed between the electron transport layer 15 and the second electrode 16.

[0046] The following is a detailed description of the structure of the photoelectric conversion element 10.

[0047] [Support]

[0048] The support 11 is not particularly limited, and for example, a substrate suitable for use in general photovoltaic conversion elements such as solar cells can be used. Examples of substrates include glass, plastic sheets, plastic films, and inorganic crystals. In addition, substrates on which at least one of a metal film, a semiconductor film, a conductive film, and an insulating film is formed on part or all of their surfaces are also suitable as the support 11. The size, thickness, etc., of the support 11 are also not particularly limited, and for example, it can be the same as or based on general photovoltaic conversion elements such as solar cells.

[0049] [First Electrode]

[0050] The first electrode 12 is, for example, a layer that supports the hole transport layer 13 and extracts holes from the photoelectric conversion layer 14. Alternatively, the first electrode 12 may function as a cathode (positive electrode).

[0051] The first electrode 12 can be formed directly on the support 11, for example. The first electrode 12 can be a transparent electrode formed of a conductor, for example. There is no particular limitation on the transparent electrode; it can be a metal oxide, metal nanowires such as silver, conductive polymers such as polyethylene dioxythiophene, carbon nanotubes, or carbon materials such as graphene, etc. Suitable examples include: tin-doped indium oxide (ITO) films, impurity-doped indium oxide (In2O3) films, impurity-doped zinc oxide (ZnO) films, fluorine-doped tin oxide (FTO) films, laminated films formed by stacking two or more of these, gold, silver, copper, aluminum, tungsten, titanium, chromium, nickel, and cobalt, etc. These can be used individually or in mixtures of two or more, and can be single-layered or laminated. Furthermore, these films can function as diffusion-preventing layers, for example. The thickness of the first electrode 12 is not particularly limited; for example, it is preferably adjusted to a sheet resistance of 5 Ω / □ to 15 Ω / □ (per unit area). The method for forming the first electrode 12 is not particularly limited. For example, it can be obtained using known film-forming methods, depending on the material used for formation. Furthermore, the shape of the first electrode 12 is not particularly limited; for example, it can be a film or a grid-like structure. The method for forming the first electrode 12 on the support 11 is not particularly limited; for example, known methods can be used, such as vacuum film formation by vacuum evaporation or sputtering. Alternatively, the first electrode 12 can also be a patterned electrode. The pattern-forming method is not particularly limited; examples include laser methods, immersion in an etching solution, and pattern formation using a mask during vacuum film formation. In this embodiment, any method can be used. Additionally, for the purpose of reducing resistance, the first electrode 12 can also be combined with metal wiring. The material of the metal wiring (metal leads) is not particularly limited; examples include aluminum, copper, silver, gold, platinum, and nickel. The metal leads can be formed on a first substrate by means of vapor deposition, sputtering, pressing, etc., and an ITO or FTO layer can be disposed thereon, or the metal leads can be disposed on ITO or FTO, and thus used together.

[0052] Hole transport layer

[0053] like Figure 1As shown, the hole transport layer 13 contains an insulating compound and a hole transport material. At least a portion of the insulating compound and at least a portion of the hole transport material are in contact with the main surface of the first electrode 12 on the side of the photoelectric conversion layer 14. Furthermore, in the hole transport layer 13, the hole transport material functions as a hole transporter. By including an insulating compound in addition to the hole transport material in the material of the hole transport layer 13, the degree of scattering of light incident on the hole transport layer 13 is increased. It is speculated that this increases the light intake in the photoelectric conversion layer 14, thereby increasing the photoelectric conversion efficiency.

[0054] Insulating compounds are compounds that are difficult to conduct electricity, typically showing a value of 10. 8 Ω·cm~10 18 Resistivity in Ω·cm.

[0055] As an insulating compound, at least one can be selected from metal oxides, metal nitrides, insulating organic compounds, and organic-inorganic hybrid compounds.

[0056] Examples of metal oxides include silicon dioxide (SiO2, refractive index 1.48, volume resistivity 1×10⁻⁶). 16 Ω·cm), aluminum oxide (Al2O3, refractive index 1.64, volume resistivity 1×10⁻⁶ Ω·cm), aluminum oxide (Al₂O₃ ... 14 Ω·cm), zirconium oxide (ZrO2), cerium oxide (CeO2, refractive index 2.13, volume resistivity 1×10 10 Ω·cm), magnesium oxide (MgO), yttrium oxide (Y₂O₃, refractive index 1.18, volume resistivity 1×10⁻⁶). 13 Ω·cm), tantalum pentoxide (Ta₂O₅), hafnium oxide (HfO₂), strontium oxide, lanthanum oxide, barium titanate (BaTiO₃, refractive index 2.43–2.49, volume resistivity 1×10⁻⁶). 12 Ω·cm), strontium titanate (SrTiO3), etc.

[0057] Examples of metal nitrides include: aluminum nitride (AlN), silicon nitride (SiN), aluminum gallium nitride (AlGaN), and boron nitride (BN).

[0058] Examples of insulating organic compounds include: acrylic resin, epoxy resin, and polystyrene.

[0059] Organic-inorganic hybrid compounds are compounds that have both carbon atoms and silicon atoms, preferably compounds that have both siloxane bonds and partial structures (hydrocarbon groups, etc.) with carbon atoms, such as sesquioxanes.

[0060] Among these, metal oxides are particularly preferred as insulating compounds.

[0061] The volume resistivity of the insulating compound is preferably 1×10⁻⁶. 8 Ω·cm or more, more preferably 1×10 9 Ω·cm or higher, and more preferably 1×10 10 Ω·cm or higher. Furthermore, the volume resistivity of the insulating compound is preferably 1×10⁻⁶. 18 Ω·cm or less, more preferably 1×10 17 Below Ω·cm, further preferably 1×10 16 Below Ω·cm.

[0062] The refractive index of the insulating compound is preferably 1.20 or higher, more preferably 1.40 or higher. For example, the refractive index of the insulating compound is 2.50 or lower. The refractive index of the insulating compound can be determined by the critical angle method.

[0063] The method for forming the hole transport layer 13 containing the insulating compound is not limited and can be appropriately selected according to the purpose, but a wet film-forming method is preferred. As a wet film-forming method, a preferred method is to prepare a dispersion of powder or sol containing the insulating compound and then coat the dispersion.

[0064] As a wet film-forming method, there are no particular limitations, and the appropriate method can be selected according to the purpose. Examples include: immersion coating, spray coating, wire rod coating, spin coating, roller coating, scraper coating, and gravure coating.

[0065] As a wet printing method, various methods can be used, such as letterpress, offset, photogravure, gravure, rubber plate, screen printing, etc.

[0066] There are no particular limitations on the method for producing the microparticles of the insulating compound. For example, if it is a metal oxide, solid-state reaction, co-precipitation, hydrothermal synthesis, sol-gel method, etc., using known raw materials such as oxides or carbonates can be used. The shape of the microparticles is also not particularly limited, and anisotropic shapes such as spherical, amorphous, rod-shaped, or plate-shaped particles can be used. However, the insulating compound in this embodiment is preferably in particle shape. When the insulating compound is in particle shape, the average particle size is preferably 1 nm to 200 nm, more preferably 1 nm to 100 nm, and even more preferably 1.5 nm to 50 nm. The average particle size of the insulating compound is set as the average value calculated by measuring the diameter (major axis when not perfectly circular) of 100 insulating compound particles using a scanning electron microscope (SEM). Furthermore, with the hole transport layer 13 formed, the average particle size can be determined by photographing a cross-section of the hole transport layer 13 with SEM and measuring the diameter (major axis when not perfectly circular) of 100 insulating compound particles. Before forming the hole transport layer 13, the average particle size of the insulating compound used to form the particle shape of the hole transport layer 13 can be determined in advance.

[0067] There are no particular limitations on the method for preparing a dispersion of insulating compounds, and it can be selected appropriately according to the purpose. For example, methods such as mechanical pulverization using known grinding devices can be listed. By the preparation method described above, a dispersion of insulating compounds can be prepared by dispersing particulate insulating compounds alone or by dispersing a mixture of insulating compounds and resins in water or a solvent.

[0068] Resins used in dispersions include, for example, polymers or copolymers based on vinyl compounds such as styrene, vinyl acetate, acrylates, and methacrylates; silicone resins, phenoxy resins, polysulfone resins, polyvinyl butyral resins, polyvinyl formal resins, polyester resins, cellulose ester resins, cellulose ether resins, urethane resins, phenolic resins, epoxy resins, polycarbonate resins, polyarylate resins, polyamide resins, and polyimide resins. These can be used individually or in combination of two or more.

[0069] Examples of solvents include: water, alcohols, ketones, esters, ethers, amides, halogenated hydrocarbons, and hydrocarbons. Examples of alcohol solvents include: methanol, ethanol, isopropyl alcohol, and α-terpineol. Examples of ketone solvents include: acetone, methyl ethyl ketone, and methyl isobutyl ketone. Examples of ester solvents include: ethyl formate, ethyl acetate, and n-butyl acetate. Examples of ether solvents include: diethyl ether, dimethoxyethane, tetrahydrofuran, dioxane, and dioxane. Examples of amide solvents include: N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone. Examples of solvents that can be used as solvents for halogenated hydrocarbons include: dichloromethane, chloroform, bromoform, iodomethane, dichloroethane, trichloroethane, trichloroethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene, bromobenzene, iodobenzene, and 1-chloronaphthalene. Examples of solvents that can be used as solvents for hydrocarbons include: n-pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, and cumene. These can be used individually or in combination with two or more.

[0070] In dispersions containing insulating compounds, or pastes containing insulating compounds obtained through sol-gel methods, acids, surfactants, chelating agents, etc., can be added to prevent particle re-aggregation. Examples of acids include hydrochloric acid, nitric acid, and acetic acid; examples of surfactants include polyoxyethylene octylphenyl ether; examples of chelating agents include acetylacetone, 2-aminoethanol, and ethylenediamine. Additionally, adding thickeners is also an effective method to improve film-forming properties. Examples of thickeners include polyethylene glycol, polyvinyl alcohol, and ethyl cellulose.

[0071] In addition to the insulating compound described above, the hole transport layer 13 also contains a compound represented by the following chemical formula (I).

[0072] Ar 1 -(L 1 -X 1 (I)

[0073] In the chemical formula (I), Ar 1 For a structure containing an aromatic ring, heteroatoms may be included among the atoms constituting the aromatic ring, Ar 1 It can have the function of -L 1 -X 1 Other substituents. For integers n greater than or equal to 1, -L is used when n is 2 or greater. 1 -X 1 The structures represented can be the same or different from each other. The upper limit of n is preferably 3 or 4. L 1 To make Ar 1 With X1 A binary linker or a single bond. X 1 It is a base that can form chemical bonds or hydrogen bonds with the first electrode 12.

[0074] (The compound represented by chemical formula (I))

[0075] In chemical formula (I), X 1 The groups are independently selected from the group consisting of dihydroxyphosphoryl (-P=O(OH)2), carboxyl (-COOH), sulfonyl (-SO3H), borate (-B(OH)2), trihalosilyl (-SiX3, where X is a halogenated group), trialkoxysilyl (-Si(OR)3, where R is an alkyl group), trihydroxysilyl, and dialkylphosphoryl.

[0076] In chemical formula (I), Ar 1 Specifically, preferred examples include aromatic ring groups, groups formed by multiple aromatic ring groups linked by single bonds, and groups formed by one or more aromatic ring groups condensed within a ring that is not aromatic.

[0077] The aromatic ring group can be monocyclic or polycyclic (e.g., 2 to 14 rings), and can have one or more (e.g., 1 to 10) heteroatoms (nitrogen, sulfur, and / or oxygen atoms, etc.). The number of ring atoms in the aromatic ring group is preferably 5 to 40.

[0078] Examples of aromatic cyclic groups include: phenyl cyclic group, pyrrole cyclic group, furan cyclic group, thiophene cyclic group, and groups formed by cyclic condensation of two or more (e.g., 2 to 14) selected from these.

[0079] The aromatic ring groups constituting the plurality of aromatic ring groups linked by single bonds can be exemplified by the aromatic ring groups described above. The number of aromatic ring groups linked by single bonds is preferably, for example, 2 to 6.

[0080] Specific examples of groups formed by the bonding of multiple aromatic cyclic groups through single bonds include biphenyl cyclogroup and bithiophene cyclogroup.

[0081] Aromatic ring groups that constitute one or more aromatic ring groups formed by condensing an aromatic ring into a non-aromatic ring can be exemplified by the aromatic ring groups described above.

[0082] In the group formed by the cyclic condensation of one or more aromatic ring groups into a non-aromatic ring, the number of aromatic ring groups cyclic condensed into the non-aromatic ring is preferably 2 to 6, for example.

[0083] In a group in which one or more aromatic ring groups are condensed into non-aromatic rings, there may be only one non-aromatic ring or there may be multiple non-aromatic rings.

[0084] In a group formed by condensing one or more aromatic rings into non-aromatic rings, the non-aromatic rings can be monocyclic or polycyclic (e.g., 2 to 14 rings) and can have one or more (e.g., 1 to 10) heteroatoms (nitrogen atom, sulfur atom and / or oxygen atom, etc.).

[0085] Specific examples of the group formed by the condensation of one or more aromatic cyclic groups into a non-aromatic ring include phenothiazine cycloalcosyl and 1,2:3,4:5,6:7,8-tetra[imino(1,2-phenylene)]cyclooctatetraene cycloalcosyl.

[0086] In chemical formula (I), L acts as a divalent linker. 1 For example, examples can be listed. 1-alkylene- 2. 1-alkylene-aromatic- 2. Here, 1 represents Ar 1 Side bond position, 2 represents X 1 The bonding position on the side. The alkylene group can be straight-chain or branched, and the number of carbon atoms is preferably 1 to 6. The aromatic cyclic group can be, for example, as Ar. 1 The aromatic cyclic group that can be formed is the same as the aromatic cyclic group described above. The alkylene group and the aromatic cyclic group may further have substituents.

[0087] As specific examples of compounds represented by chemical formula (I), compounds (A-01) to (A-21) with the following structures can be listed.

[0088] [Chemistry 1]

[0089]

[0090] [Chemistry 2]

[0091]

[0092] [Chemistry 3]

[0093]

[0094] [Chemistry 4]

[0095]

[0096] [Chemistry 5]

[0097]

[0098] The compound represented by chemical formula (I) may, for example, be formed on the first electrode 12 in the form of a monolayer.

[0099] The compound represented by chemical formula (1) can be formed on the main surface of the first electrode 12 in a dispersed form, in other words, in a form with gaps. The aforementioned insulating compound can be formed in a form that fills the gaps.

[0100] (The compound represented by chemical formula (II))

[0101] In addition to the insulating compound and the compound represented by chemical formula (I) described above, the hole transport layer 13 may also contain the compound represented by chemical formula (II) below. In other words, the compound represented by chemical formula (II) below can be used as a co-adsorbent. In a preferred embodiment of the hole transport layer 13, the compound represented by chemical formula (II) forms a chemical bond or a hydrogen bond with the first electrode 12.

[0102] A 1 -L 2 -X 2 ... (II)

[0103] A 1 The ring contains one or more organic amino groups selected from monoalkylamino, dialkylamino, monoarylamino, diarylamino, aminocarbonylamino, alkylcarbonylamino, alkylsulfonylamino, etc., alkoxy, hydroxy, carboxyl, dihydroxyphosphoryl, dialkylphosphoryl, hydroxysulfonyl, amino, monoalkylaminocarbonyl, dialkylaminocarbonyl, alkylcarbonyloxy, alkoxycarbonyl, aminocarbonyl, aminosulfonyl, nitrogen-containing heterocyclic groups (which may or may not be aromatic, and may be monocyclic or polycyclic, with the number of ring atoms preferably being 5 to 15, and the number of nitrogen atoms in the ring atoms preferably being 1 to 5, and may have (preferably 1 to 3) heterocyclic groups other than nitrogen atoms). Atoms; for example, substituents or structural groups in the group consisting of pyridine, quinoline, aziridine, azetidine, pyrrolidine, imidazoline, imidazoline-2-one, 2,3-dihydro-1H-pyrrole, pyrrole, pyrazole, imidazoline, 1H-1,2,3-triazole, 2H-1,2,3-triazole, thiazole, morpholine, piperidine, piperazine, pyrazine, hexamethyleneimine, 1H-azepine, indole, 2,3-trimethyleneindoline, quinoxaline. A 1 The substituents or structures listed above may be used. Furthermore, when the substituents or structures listed above have an alkyl moiety (including the alkyl moiety in an alkoxy group, etc.), the alkyl group may be either straight-chain or branched, and the number of carbon atoms is preferably 1 to 8.

[0104] L 2 To make A 1 With X 2 A binary linker or a single bond. X 2 It is a group that can form chemical bonds or hydrogen bonds with the first electrode.

[0105] In the compound represented by chemical formula (II), through A 1 The hydrophilic properties improve the wettability of the perovskite solution coated on the hole transport layer 13. By improving the wettability of the perovskite solution, the perovskite layer can be coated with uniform thickness, and it is believed that it can reduce fluctuations, especially when coating large areas.

[0106] In chemical formula (II), in A 1 When the indicated radical contains a monoarylamino or diarylamino group, the aryl moiety in these groups can be, for example, associated with Ar. 1 The aromatic ring groups that can be formed are the same as the aromatic ring groups described above.

[0107] A 1 The represented atomic group may be an organic amino group such as monoalkylamino, dialkylamino, monoarylamino, diarylamino, aminocarbonylamino, alkylcarbonylamino, alkylsulfonylamino, etc., alkoxy, dialkylphosphoryl, amino, monoalkylaminocarbonyl, dialkylaminocarbonyl, alkylcarbonyloxy, alkoxycarbonyl, aminocarbonyl, aminosulfonyl, or nitrogen-containing heterocyclic group, and further has one or more (preferably 1 to 6) substituents. These groups may further have substituents that are similar to X in chemical formula (II). 2 or -L 2 -X 2 The same group can be formed. In compounds represented by chemical formula (II), it is also preferable that there are two or more (e.g., 2 to 6) -L groups from chemical formula (II) present in whole. 2 -X 2 Formable bases.

[0108] In chemical formula (II), X 2 The groups are independently selected from the group consisting of dihydroxyphosphoryl (-P=O(OH)2), carboxyl (-COOH), sulfonyl (-SO3H), borate (-B(OH)2), trihalosilyl (-SiX3, where X is a halogenated group), trialkoxysilyl (-Si(OR)3, where R is an alkyl group), trihydroxysilyl, and dialkylphosphoryl.

[0109] In chemical formula (II), L acts as a divalent linker. 2Examples include: alkylene groups (which can be linear or branched, preferably with 1 to 8 carbon atoms), vinylene groups, vinylidene groups, ethynylene groups, and aromatic cyclic groups (e.g., Ar in chemical formula (I)). 1 Aromatic cyclic groups (which can be formed, including aromatic cyclic groups), non-aromatic cyclic groups (which can be monocyclic or polycyclic and may have heteroatoms; for example, piperazine cyclic groups), -O-, -S-, -NR- N -(R) N The atom is a hydrogen atom or an alkyl group; the alkyl group can be straight-chain or branched, and preferably has 1 to 8 carbon atoms), and a divalent linker group comprising two or more of these (e.g., 2 to 6). The divalent linker group comprising two or more of the above combinations can be a combination of the same type of group (however, it does not include combinations in which alkylene groups are continuously bonded to each other).

[0110] Where possible, these divalent linking groups may further have one or more (e.g., 1 to 6) substituents, for example, they may have one or more (e.g., 1 to 6) substituents as A. 1 or X 2 The same base as the described base is used as a substituent.

[0111] Specific examples of compounds represented by chemical formula (II) include: 3-methoxypropionic acid, 3-hydroxypropionic acid, 2-hydroxypropionic acid, malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, phthalic acid, terephthalic acid, maleic acid, fumaric acid, citrate, succinic acid, methylene succinic acid, allyl malonic acid, isopropyl succinic acid, ethynyl dicarboxylic acid, dimethyl terephthalate, diethyl terephthalate, 4,4'- Biphenyl dicarboxylic acid, 4,4'-biphenyl dicarboxylic acid diethyl ester, 4-methoxybenzoic acid, 3,4-dimethoxybenzoic acid, 4-(methylamino)benzoic acid, 4-(methylamino)benzenesulfonic acid, 4-(methylamino)butyric acid, 3-(carboxymethylamino)propionic acid, 6-acetoxy-2-naphthoic acid, acetylsalicylic acid, 4-(methoxycarbonyl)cyclohexanecarboxylic acid, 4-(methoxycarbonyl)phenylboronic acid, 4-(N,N-diethyl) (Aminocarbonyl)phenylboronic acid, 3-(methylaminocarbonyl)acrylic acid, N-(aminocarbonyl)aspartic acid, 4-acetylaminobenzoic acid, 2-(acetylamino)acrylic acid, gallic acid, 4-pyridinecarboxylic acid, 6-quinolinecarboxylic acid, aspartic acid, 2,2-diethoxyethylphosphonic acid, methylene diphosphonic acid, 1,2-ethylene diphosphonic acid, tetraethyl 1,2-ethylene diphosphonate, 1,3-propylidene diphosphonic acid, 3,4-dimethyl... Oxyphenylphosphonic acid, (4-hydroxybenzyl)phosphonic acid, 4-hydroxyphenylphosphonic acid, [3-(3-carboxypiperazin-1-yl)propyl]phosphonic acid, (pyridin-4-ylmethyl)phosphonic acid, (pyridin-3-ylmethyl)phosphonic acid, 4-phosphonobenzoic acid, 3-phosphonopropionic acid, 4-phosphonobutyric acid, diethyl(4-methoxybenzyl)phosphonate, p-carboxybenzenesulfonamide, 2-(dimethylamino)ethanesulfonic acid, 1,2-ethanesulfonic acid, etc.

[0112] As L 2 Specific examples include: alkylene compounds such as 1,1-ethylene, 1,2-ethylene, 1,3-propylene, and 2-ethyl-1,6-hexylene, a portion of which may be an alkenyl group with a carbon-carbon double bond or an alkynyl group with a triple bond. Additionally, examples include: aryl groups such as 1,2-phenylene, 1,4-phenylene, 1,5-naphthylene, and 4,4'-biphenylene; and divalent heterocycles such as 2,5-thienylene, 5,5'-bithienylene, 2,5-thieno[3,2-b]thienylene, and 2,6-pyridylene.

[0113] Among the compounds represented by the above chemical formula (II), those that form salts from nitrogen atoms and anions include: ammonium salts, aziridinium salts, azirinium salts, azetidinium salts, pyrrolidinium salts, pyrrolinium salts, pyrazolinium salts, pyrrolinium salts, pyrazolinium salts, imidazolinium salts, triazolinium salts, tetrazolinium salts, piperidinium salts, piperazinium salts, pyridinium salts, and pyrazinium salts. The salts include morpholinium salt, thiazolinium salt, azepanium salt, azepinium salt, indolinium salt, quinolinium salt, isoquinolinium salt, quinoxalinium salt, phenanthrolinium salt, and phenazinium salt. The acid that reacts with the compound represented by the above chemical formula (II) to form a salt can be any one of the organic or inorganic acids described later, or a mixture thereof, that forms an acid-addition salt.

[0114] Specific examples of compounds represented by chemical formula (II) include compounds (B-01) to (B-52) with the following structures.

[0115] [Chemistry 6]

[0116]

[0117] [Chemistry 7]

[0118]

[0119] [Chemistry 8]

[0120]

[0121] [Chemistry 9]

[0122]

[0123] [Chemistry 10]

[0124]

[0125] [Chemistry 11]

[0126]

[0127] The compound represented by chemical formula (II) may, for example, be formed on the first electrode 12 in the form of a monolayer.

[0128] In the hole transport layer 13, the total content of the compound represented by chemical formula (I) (which includes the form of the above-mentioned salt) and the compound represented by chemical formula (II) (which includes the form of the above-mentioned salt) relative to the mass of the hole transport layer 13 is preferably 70% to 100% by mass, more preferably 90% to 100% by mass, and even more preferably 99% to 100% by mass.

[0129] The molar ratio of the compound represented by chemical formula (II) (which includes the form of the above-mentioned salt) to the compound represented by chemical formula (I) (which includes the form of the above-mentioned salt) is preferably 1:100 to 1:1, more preferably 1:80 to 1:2, and even more preferably 1:50 to 1:5.

[0130] In the hole transport layer 13, the ratio of [mass of the compound represented by chemical formula (I)] to [mass of the insulating compound] is preferably 1 / 10 to 1 / 20000, more preferably 1 / 50 to 1 / 10000.

[0131] The mass of the compound represented by chemical formula (I) can be calculated, for example, by measuring the adsorption amount based on cyclic voltammetry. Furthermore, regarding the mass of the insulating compound, a film is formed by spin-coating a solution containing the insulating compound onto a surface such as glass, and the cross-section of the resulting film is observed using an electron microscope. Using the measured film thickness, and assuming that the nanoparticles are densely packed, the weight is calculated by multiplying the film thickness by 0.74.

[0132] The thickness of the hole transport layer 13 is preferably 10 nm to 300 nm, more preferably 20 nm to 150 nm, and even more preferably 30 nm to 100 nm.

[0133] (Methods for forming a hole transport layer)

[0134] The method for forming the hole transport layer 13 is not particularly limited. Examples include: adsorbing the compound represented by chemical formula (I), or the compound represented by chemical formulas (I) and (II) onto the first electrode 12, and then coating a dispersion of insulating compound; adsorbing the compound represented by chemical formula (I), or the compound represented by chemical formulas (I) and (II) onto the first electrode 12 after coating the dispersion of insulating compound onto the first electrode 12; pre-containing the compound represented by chemical formula (I), or the compound represented by chemical formulas (I) and (II) into the dispersion of insulating compound, and then coating the solution onto the first electrode 12. In particular, the method of adsorbing the compound represented by chemical formula (I), or the compound represented by chemical formulas (I) and (II) onto the first electrode 12, and then coating the dispersion of insulating compound onto the first electrode 12, is most preferred.

[0135] The method for adsorbing the compound represented by chemical formula (I), or the compound represented by chemical formulas (I) and (II), onto the first electrode 12 is not particularly limited. For example, it is sufficient to dissolve the compound represented by chemical formula (I), or the compound represented by chemical formulas (I) and (II), in a solvent and bring it into contact with and bind to the first electrode 12. The binding of the compound represented by chemical formula (I) to the first electrode 12 and the binding of the compound represented by chemical formula (II) to the first electrode 12 are not particularly limited; they can be physical binding or chemical bonding. The type of bond is also not particularly limited; for example, it can be any one of hydrogen bonds, ester bonds, chelate bonds, etc. The solvent used to dissolve the compound represented by chemical formula (I) and the compound represented by chemical formula (II) is also not particularly limited; for example, it can be one of water or an organic solvent, or both. More specifically, the following solvents can be used: alcohols such as water, 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; nitrile compounds such as acetonitrile and 3-methoxypropionitrile; aromatic compounds such as benzene, toluene, and chlorobenzene; halogen solvents such as dichloromethane and chloroform; and fluorinated solvents such as chlorofluorocarbons, hydrochlorofluorocarbons, and hydrofluorocarbons. These can be used alone or in combination of two or more.

[0136] The specific method for adsorbing the compound represented by chemical formula (I), or the compound represented by chemical formulas (I) and (II) onto the first electrode 12 to form a monolayer is not particularly limited. Known methods such as immersion, spraying, spin coating, and rod coating are examples. The adsorption temperature is not particularly limited, but is preferably -20°C to 100°C, more preferably 0°C to 50°C. The adsorption time is also not particularly limited, but is preferably 1 second to 48 hours, more preferably 10 seconds to 1 hour.

[0137] Furthermore, the adsorption treatment may be followed by washing, or it may not be necessary. The washing method is not particularly limited; for example, known methods may be suitable.

[0138] After the adsorption treatment or the cleaning, a heat treatment may or may not be performed. The preferred temperature for the heat treatment is 50°C to 150°C, more preferably 70°C to 120°C. The preferred heat treatment time is 1 second to 48 hours, more preferably 10 seconds to 1 hour. Furthermore, the heat treatment may be performed, for example, at atmospheric pressure or in a vacuum.

[0139] In this embodiment, the "substituent" is not particularly limited, and examples include: alkyl, alkenyl, alkynyl, unsaturated aliphatic hydrocarbon group, alkoxy, aralkyl, aryl, arylalenyl, heteroaryl, halogen atom (fluorine atom, chlorine atom and / or bromine atom, etc.), hydroxyl (-OH), mercapto (-SH), alkylthio (-SR, R is alkyl), amino, sulfonyl, nitro, diazo, cyano, nitrile, trifluoromethyl, etc.

[0140] Furthermore, in this embodiment, if the compound contains tautomers or stereoisomers (e.g., geometric isomers, conformational isomers, and optical isomers), any isomer may be used in this embodiment unless otherwise specified. Additionally, in this embodiment, if the compound represented by chemical formula (I) or chemical formula (II) can form a salt, the salt may also be used in this embodiment unless otherwise specified. The salt may be an acid addition salt or a base addition salt. Furthermore, the acid forming the acid addition salt may be an inorganic acid or an organic acid, and the base forming the base addition salt may be an inorganic base or an organic base. The inorganic acids are not particularly limited, and examples include: sulfuric acid, phosphoric acid, hydrofluoric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, hypofluoric acid, hypochlorous acid, hypobromic acid, hypoiodic acid, fluorite, chlorous acid, bromic acid, iodic acid, fluoric acid, chloric acid, bromic acid, iodic acid, perfluoric acid, perchloric acid, perbromic acid, and periodic acid. The organic acids are also not particularly limited, and examples include: p-toluenesulfonic acid, methanesulfonic acid, oxalic acid, p-bromobenzenesulfonic acid, carbonic acid, succinic acid, citric acid, benzoic acid, and acetic acid. The inorganic bases are also not particularly limited, and examples include: ammonium hydroxide, alkali metal hydroxides, alkaline earth metal hydroxides, carbonates, and bicarbonates. More specifically, examples include: sodium hydroxide, potassium hydroxide, potassium carbonate, sodium carbonate, sodium bicarbonate, potassium bicarbonate, calcium hydroxide, and calcium carbonate. The organic bases are also not particularly limited, and examples include: ethanolamine, triethylamine, and tris(hydroxymethyl)aminomethane. There are no particular limitations on the methods for producing these salts; for example, they can be produced by using known methods to appropriately add such acids or bases to the compounds.

[0141] The mass ratio of the compound represented by chemical formula (I) to the mass of the insulating compound (m2) preferably satisfies the relationship of the following formula (A).

[0142] m1 / m2 = 1 / 10 ~ 1 / 20000 (A)

[0143] [Photoelectric conversion layer]

[0144] The photoelectric conversion layer 14 is not particularly limited, and may be the same as the photoelectric conversion layer used in general photoelectric conversion elements such as solar cells. The photoelectric conversion layer 14 may, for example, contain a perovskite compound. The perovskite compound may, for example, be an organic-inorganic perovskite compound represented by the following chemical formula (III).

[0145] XαYβZγ. . . (III)

[0146] In the chemical formula (III), the ratio of α:β:γ is 3:1:1, where β and γ represent integers greater than 1. X represents a halide ion, Y represents an organic compound containing an amino group, and Z represents a metal ion. The photoelectric conversion layer 14 containing the perovskite compound is preferably disposed adjacent to the electron transport layer 15. Furthermore, the ratio of α:β:γ is not necessarily 3:1:1, such as 3:1.05:0.95.

[0147] There are no particular restrictions on X in the chemical formula (III), and it can be selected appropriately according to the purpose. For example, halide ions such as chlorine, bromine, and iodine can be listed. One of these can be used alone, or two or more can be used together.

[0148] As Y in the aforementioned chemical formula (III), examples include: alkylamine compound ions (organic compounds with an amino group) such as methylamine, ethylamine, n-butylamine, and formamidinium, or, not limited to organic compounds, alkali metal ions such as cesium, potassium, and rubidium. Alkylamine compound ions or alkali metal ions may be used individually or in combination with two or more. Furthermore, organic (alkylamine compound ions) and inorganic (alkali metal ions) ions may be used together; for example, cesium ions and formamidinium ions may be used together.

[0149] There are no particular limitations on Z in the chemical formula (III), and it can be selected appropriately according to the purpose. For example, metals such as lead, indium, antimony, tin, copper, and bismuth can be listed. One of these can be used alone, or two or more can be used in combination. Lead is particularly preferred, especially the combination of lead and tin. Furthermore, the perovskite layer preferably exhibits a layered perovskite structure, which is formed by alternating layers of halide metals and organic cation molecules. The perovskite layer may contain alkali metals. When the perovskite layer contains at least an alkali metal, it is advantageous in terms of improving output. Examples of alkali metals include cesium, rubidium, and potassium. Among these, cesium is preferred.

[0150] As described above, the photoelectric conversion layer 14 can be a perovskite layer formed from a perovskite compound. There are no particular limitations on the method for forming such a perovskite layer, and it can be selected appropriately according to the purpose. For example, methods such as coating a solution containing dissolved or dispersed metal halide and alkyl halide and then drying it can be listed.

[0151] In addition, as a method for forming a perovskite layer, examples include a two-stage precipitation method in which a solution containing dissolved or dispersed metal halide is coated and dried, and then immersed in a solution containing dissolved alkylamine halide to form a perovskite compound.

[0152] In addition, as a method for forming a perovskite layer, for example, a method can be listed where a solution containing dissolved or dispersed metal halide and alkyl halogenated amine is coated, and a solvent with poor solubility for the perovskite compound (a solvent with low solubility) is added to induce crystallization.

[0153] In addition, other methods for forming perovskite layers include, for example, evaporating metal halides in a gas filled with methylamine or the like.

[0154] A particularly preferred method for forming a perovskite layer is to simultaneously coat a solution containing dissolved or dispersed metal halides and alkyl halides, while adding a solvent unsuitable for the perovskite compound to induce crystallization. There are no particular limitations on the method of coating these solutions; appropriate methods can be selected depending on the purpose. Examples include: dipping, spin coating, spraying, dip coating, roller coating, and air knife coating. Alternatively, a method for coating the solution can also be a precipitation method using a supercritical fluid such as carbon dioxide. Regarding the method of crystallization by adding the aforementioned unsuitable solvent, examples of unsuitable solvents 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; nitrile compounds such as acetonitrile and 3-methoxypropionitrile; aromatic hydrocarbons such as benzene, toluene, and chlorobenzene; halogen solvents such as dichloromethane and chloroform; and fluorinated solvents such as chlorofluorocarbons, hydrochlorofluorocarbons, and hydrofluorocarbons.

[0155] The thickness of the photoelectric conversion layer 14 (e.g., a light absorption layer, such as a perovskite layer) is not particularly limited, but from the viewpoint of further suppressing performance degradation caused by defects or stripping, it is preferably 50 nm to 1200 nm, more preferably 200 nm to 1000 nm.

[0156] An interface layer can be formed between the photoelectric conversion layer 14 and the electron transport layer 15. Since various crystal defects exist on the surface or at the grain boundaries of the photoelectric conversion layer 14, it is effective to passivate these defects by placing a compound containing an organic salt between the photoelectric conversion layer 14 and the electron transport layer 15. Specific examples of such organic salts include salts obtained from the following cations and anions: cations are monovalent or divalent cations obtained by reacting amino compounds such as methylamine, n-butylamine, tert-butylamine, n-hexyl-dimethylamine, pyridine, aniline, 2-phenylethylamine, 5-aminopentanoic acid, ethylenediamine, morpholine, piperidine, and piperazine with protons; anions are anions formed from halogens such as fluorine, chlorine, bromine, and iodine, carboxylic acids, sulfuric acid, nitric acid, phosphoric acid, oxalic acid, phthalic acid, succinic acid, thiocyanate, and isocyanate.

[0157] If the interface layer is too thick, it may become a resistive component; therefore, it is preferable to form a thin layer. There are no particular limitations on the formation method; examples include using a solution containing the aforementioned salt and forming it through spin coating, inkjet printing, casting, spray coating, etc.

[0158] [Electron transport layer]

[0159] There are no particular limitations on the material used in the electron transport layer 15, and it can be selected appropriately according to the purpose, but a semiconductor material is preferred. There are no particular limitations on the semiconductor material, and known semiconductor materials can be used, such as monomeric semiconductors, compound semiconductors, organic n-type semiconductors, etc.

[0160] There are no particular limitations on the single semiconductor, such as silicon and germanium.

[0161] The compound semiconductor is not particularly limited, and 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.; and tellurides of cadmium, etc. Other compound semiconductors include phosphides of zinc, gallium, indium, cadmium, etc.; gallium arsenide; copper-indium-selenide; and copper-indium-sulfide.

[0162] The organic n-type semiconductor is not particularly limited, and examples include: perylene tetracarboxylic anhydride, perylene tetracarboxylic diimide compounds, naphthalene diimide-bithiophene copolymers, benzobisimidazole-benzophenanthrene porphyrin polymers, and C 60 C 70 PCBM ([6,6]-phenyl-C 61 Fullerene compounds such as methyl butyrate, carbonyl-bridged bithiazole compounds, ALq3 (tris(8-hydroxyquinoline)aluminum), triphenylbipyridine compounds, thiophene compounds, oxadiazole compounds, etc.

[0163] Among the materials used in the electron transport layer 15, organic n-type semiconductors are particularly preferred.

[0164] The material used in the formation of the electron transport layer 15 can be a single material or two or more materials used together. In addition, there are no particular restrictions on the crystal form of the semiconductor material, and it can be selected appropriately according to the purpose. It can be single crystal, polycrystalline, or amorphous.

[0165] There is no particular limitation on the thickness of the electron transport layer 15, which can be appropriately selected according to the purpose, but it is preferably 5 nm to 1000 nm, and more preferably 10 nm to 700 nm.

[0166] There are no particular limitations on the method for forming the electron transport layer 15, and it can be selected appropriately according to the purpose. For example, methods for forming thin films in a vacuum (vacuum film formation method) and wet film formation method can be listed. As a vacuum film formation method, examples include sputtering, pulsed laser deposition (PLD), ion beam sputtering, ion-assisted methods, ion plating, vacuum evaporation, atomic layer deposition (ALD), and chemical vapor deposition (CVD). As a wet film formation method, methods that form by coating a solvent containing dissolved electron transport materials can be listed, or in the case of oxide semiconductors, sol-gel methods can be listed. The sol-gel method is a method in which a solution is hydrolyzed or polymerized, condensed, or otherwise chemically reacted to form a gel, and then densification is promoted by heat treatment. When using the sol-gel method, there are no particular limitations on the coating method of the sol solution, and it can be selected appropriately according to the purpose. Examples include: dip coating, spray coating, wire rod coating, spin coating, roller coating, doctor blade coating, and photogravure coating. Additionally, examples of wet printing methods include: letterpress printing, offset printing, photogravure printing, gravure printing, rubber printing, and screen printing. Furthermore, the temperature for heat treatment after coating the sol solution is preferably 80°C or higher, and more preferably 100°C or higher.

[0167] After forming the electron transport layer 15, an electron injection layer (hole blocking layer) can be formed between it and the second electrode 16. Materials used in the electron injection layer include bathocuproine (BCP) and cesium-doped materials. The electron injection layer is preferably 1 nm to 100 nm, more preferably 3 nm to 20 nm.

[0168] [Second Electrode]

[0169] The second electrode 16 (e.g., a back electrode) is, for example, a layer that has the function of extracting electrons from the photoelectric conversion layer 14 via an electron transport layer. Alternatively, the second electrode 16 may function as an anode (negative electrode).

[0170] The second electrode 16 can be directly formed on the electron transport layer (also known as the electron injection layer) 15. Furthermore, the material of the second electrode 16 is not particularly limited; for example, the same material as the first electrode 12 can be used. There are no particular restrictions on the shape, structure, or size of the second electrode 16, and it can be appropriately selected according to the purpose. Examples of materials that can be used for the second electrode 16 include: metals, carbon compounds, conductive metal oxides, and conductive polymers.

[0171] Examples of metals mentioned include platinum, gold, silver, copper, and aluminum.

[0172] Examples of such carbon compounds include graphite, fullerene, carbon nanotubes, and graphene.

[0173] Examples of conductive metal oxides include ITO, FTO, and antimony-doped tin oxide (ATO).

[0174] Examples of such conductive polymers include polythiophene and polyaniline.

[0175] The materials used in the formation of the second electrode 16 may be a single material or two or more materials used together.

[0176] The second electrode 16 can be appropriately formed on the electron transport layer 15 by means of coating, lamination, vacuum evaporation, CVD, bonding, etc., depending on the type of material used or the type of hole transport layer 13.

[0177] Furthermore, in the photoelectric conversion element 10 of this embodiment, at least one of the first electrode 12 and the second electrode 16 is preferably substantially transparent. When using the photoelectric conversion element 10 of this embodiment, it is preferable to make the electrodes transparent so that incident light enters from the electrode side. In this case, it is preferable to use a light-reflecting material in the back electrode (the electrode opposite to the transparent electrode, such as the second electrode 16), and preferably to use glass, plastic, metal thin film, etc., coated with metal or conductive oxide. In addition, providing an anti-reflective layer on the electrode on the incident light side is also an effective means.

[0178] Furthermore, the structure of the photoelectric conversion element 10 is not limited to Figure 1 The structure. For example, the support 11 can also be configured in relation to... Figure 1 The opposite side ( Figure 1 The second electrode 16 (above the middle electrode 16), the electron transport layer 15, the photoelectric conversion layer 14, the hole transport layer 13, and the first electrode 12 can be stacked on the support 11 in the aforementioned order. Furthermore, for example, as described above, other constituent components may or may not exist between the layers of 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. Furthermore, while an example of a transparent electrode 12 and a back electrode 16 has been described, the photoelectric conversion element 10 is not limited to this. For example, in the photoelectric conversion element 10, conversely, the first electrode 12 may be a back electrode and the second electrode 16 may be a transparent electrode.

[0179] [seal]

[0180] The photoelectric conversion element 10 (e.g., a solar cell) in this embodiment is preferably sealed to protect the device (the photoelectric conversion element 10 in this embodiment) from the influence of water or oxygen. The sealing structure is not particularly limited; for example, it can be the same as that of a general photoelectric conversion element (e.g., a solar cell). Specifically, for example, the sealing material can be applied only to the outer periphery of the photoelectric conversion element 10 in this embodiment and covered with glass or a film; the sealing material can be applied to the entire surface of the photoelectric conversion element 10 in this embodiment and covered with glass or a film; or the sealing material can be applied only to the entire surface of the photoelectric conversion element 10 in this embodiment.

[0181] There are no particular restrictions on the material used for sealing components; it can be selected appropriately according to the purpose. For example, epoxy resin or acrylic resin is preferred and then cured. It may not be cured, or only partially cured.

[0182] The epoxy resin is not particularly limited, and examples include: water-dispersible, solvent-free, solid, heat-curing, curing agent-mixed, and UV-curing types. Heat-curing and UV-curing types are preferred, with UV-curing types being more preferable. Furthermore, even UV-curing types can be heated, and it is preferable to heat even after UV curing. Specific examples of epoxy resins include: bisphenol A type, bisphenol F type, phenolic varnish type, cyclic aliphatic type, long-chain aliphatic type, glycidyl amine type, glycidyl ether type, and glycidyl ester type. These can be used alone or in combination of two or more. Additionally, curing agents or various additives are preferably mixed into the epoxy resin as needed. Commercially available epoxy resin compositions can be used in this embodiment. Among these, commercially available epoxy resin compositions developed for use in solar cells or organic electroluminescence (EL) devices can be used particularly effectively in this embodiment. Commercially available epoxy resin compositions include, for example: TB3118, TB3114, TB3124, TB3125F (manufactured by ThreeBond Inc.), WorldRock 5910, WorldRock 5920, WorldRock 8723 (manufactured by Kyoritsu Chemical Industry Co., Ltd.), WB90US(P), WB90US-HV (manufactured by MORESCO).

[0183] The acrylic resin used is not particularly limited; for example, commercially available resins developed for use in solar cells or organic EL devices can be used effectively. Examples of commercially available acrylic resin compositions include TB3035B and TB3035C (manufactured by ThreeBond Corporation).

[0184] There are no particular limitations on the type of hardener used; it can be selected appropriately according to the purpose. Examples include amine-based, anhydride-based, polyamide-based, and other hardeners. Examples of amine-based hardeners include aliphatic polyamines such as diethylenetriamine and triethylenetetramine, and aromatic polyamines such as m-phenylenediamine, diaminodiphenylmethane, and diaminodiphenyl sulfone. Examples of anhydride-based hardeners include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, pyromellitic dianhydride, het anhydride, and dodecenyl succinic anhydride. Examples of other hardeners include imidazoles and polythiols. These can be used alone or in combination of two or more.

[0185] There are no particular limitations on the additives used, and they can be selected appropriately according to the purpose. Examples include: fillers, interstitials, polymerization initiators, desiccants, curing accelerators, coupling agents, flexible agents, colorants, flame retardants, antioxidants, and organic solvents. Among these, fillers, interstitials, curing accelerators, polymerization initiators, and desiccants are preferred, and fillers and polymerization initiators are more preferred. By including fillers as additives, the penetration of moisture or oxygen can be suppressed, thereby achieving effects such as reduced volume shrinkage during curing, reduced gas escape during curing or heating, improved mechanical strength, and control of thermal conductivity or flowability. Therefore, including fillers as additives is very effective in maintaining stable output in various environments.

[0186] Furthermore, the output characteristics and durability of photoelectric conversion elements are affected not only by intruding moisture or oxygen, but also by the escaping gases generated during the hardening or heating of the sealing components. In particular, the escaping gases generated during heating have a significant impact on output characteristics when stored in high-temperature environments. By incorporating fillers, spacers, or desiccants into the sealing components, the intrusion of moisture or oxygen can be inhibited. In addition, the amount of sealing components used can be reduced, thereby reducing escaping gases. Incorporating fillers, spacers, or desiccants into the sealing components is effective not only during hardening but also when storing photoelectric conversion elements in high-temperature environments.

[0187] There are no particular limitations on the filler material used, and it can be selected appropriately according to the purpose. Examples include: crystalline or amorphous silicate minerals such as silica and talc, inorganic fillers such as alumina, aluminum nitride, silicon nitride, calcium silicate, and calcium carbonate. Among these, hydrotalcite is particularly preferred. In addition, these materials can be used alone or in combination of two or more.

[0188] 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, more preferably 1 μm or more and 5 μm or less. If the average primary particle size of the filler is within the preferred range, the effect of inhibiting the intrusion of moisture or oxygen can be sufficiently obtained, the viscosity becomes appropriate, the adhesion to the substrate or the defoaming property is improved, and the control of the width of the sealing part or the workability is also effective.

[0189] The content of the filler material, relative to the total amount of the sealing component (100 parts by weight), is preferably 10 parts by weight or more and 90 parts by weight or less, more preferably 20 parts by weight or more and 70 parts by weight or less. With the filler material content within the preferred range, sufficient inhibition of moisture or oxygen penetration can be achieved, the viscosity becomes appropriate, and the sealing performance and workability become good.

[0190] The gap agent is also called a gap control agent or spacer. By including a gap material as an additive, the gap of the sealing part can be controlled. For example, when a sealing member is applied to a first substrate or a first electrode, and a second substrate is placed on it for sealing, by mixing the gap agent with the sealing member, the gap of the sealing part is consistent with the size of the gap agent, so the gap of the sealing part can be easily controlled.

[0191] The interstitial agent is not particularly limited, but is preferably granular with uniform particle size and high solvent or heat resistance, and can be selected appropriately according to the purpose. The interstitial agent is preferably one with high affinity for epoxy resin and spherical particle shape. Specifically, glass beads, silica microparticles, organic resin microparticles, etc., are preferred. One or more of these can be used alone or in combination. The particle size of the interstitial agent can be selected according to the desired gap in the sealing part, preferably 1 μm or more and 100 μm or less, more preferably 5 μm or more and 50 μm or less.

[0192] There are no particular limitations on the polymerization initiator used. Examples include polymerization initiators that use thermal or photo-initiated polymerization, which can be selected appropriately according to the purpose. Examples include thermal polymerization initiators and photopolymerization initiators. Thermal polymerization initiators are compounds that generate active species such as free radicals or cations through heating. Examples include azo compounds such as 2,2'-azobisisobutyronitrile (AIBN) and peroxides such as benzoyl peroxide (BPO). As thermal cationic polymerization initiators, benzene sulfonates or alkyl sulfonates can be used. In the case of epoxy resins, photocationic polymerization initiators are preferably used. When a photocationic polymerization initiator is mixed into an epoxy resin and irradiated with light, the photocationic polymerization initiator decomposes, producing an acid. The acid induces the polymerization of the epoxy resin, and the curing reaction proceeds. Photocationic polymerization initiators have the advantages of low volume shrinkage during curing, no oxygen hindrance, and high storage stability.

[0193] Examples of photocationic polymerization initiators include aromatic diazonium salts, aromatic ferrophosphate salts, aromatic sulfonium salts, metallocene compounds, and silanol-aluminum complexes. Additionally, photoacid generators capable of producing acid upon light irradiation can also be used as polymerization initiators. These photoacid generators function as acids initiating cationic polymerization and include ionic sulfonium salts or ferrophosphate salts containing both cationic and anionic portions. These can be used alone or in combination of two or more.

[0194] The amount of the polymerization initiator added is not particularly limited and may vary depending on the material used. Preferably, it is 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, relative to the total amount of the sealing component (100 parts by mass). By adding the amount within the preferred range, curing can be appropriately achieved, the residue of uncured material can be reduced, and excessive gas escape can be prevented.

[0195] The desiccant (also known as a moisture absorber) is a material that physically or chemically adsorbs and absorbs moisture. By containing the desiccant in the sealing component, moisture resistance can be further improved and the impact of escaping gas can be reduced. There are no particular limitations on the desiccant; it can be selected appropriately according to the purpose. However, particulate desiccants are preferred, such as: calcium oxide, barium oxide, magnesium oxide, magnesium sulfate, sodium sulfate, calcium chloride, silica gel, molecular sieves, zeolites, and other inorganic water-absorbing materials. Among these, zeolites with high moisture absorption are preferred. These can be used alone or in combination of two or more.

[0196] The curing accelerator (also known as a curing catalyst) is a material that accelerates the curing rate and is mainly used in thermosetting epoxy resins. There are no particular limitations on the curing accelerator; it can be selected appropriately according to the purpose. Examples include: tertiary amines or tertiary amine salts such as 1,8-diazabicyclo(5,4,0)-undecene-7 (DBU) or 1,5-diazabicyclo(4,3,0)-nonene-5 (DBN); imidazole series such as 1-cyanoethyl-2-ethyl-4-methylimidazolium or 2-ethyl-4-methylimidazolium; and phosphine or phosphonium salts such as triphenylphosphine or tetraphenylphosphonium-tetraphenylborate. These can be used alone or in combination of two or more.

[0197] The coupling agent is not particularly limited as long as it has the effect of improving molecular bonding strength, and can be selected appropriately according to the purpose. For example, silane coupling agents can be listed. Specifically, examples include: 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-methacryloyloxypropyltrimethoxysilane, and other silane coupling agents. These can be used individually or in combination of two or more.

[0198] In this embodiment, a sheet adhesive can be used, for example. A sheet adhesive is, for example, an adhesive in which a resin layer is pre-formed on a sheet using a sealing resin. The sheet can be glass or a film with high gas barrier properties. Alternatively, the sheet adhesive can be formed solely from the sealing resin. The sheet adhesive can also be attached to a sealing film. In this case, it can be bonded to the device after a structure is formed in which a hollow portion is provided in the sheet constituting the sheet adhesive attached to the sealing film is formed.

[0199] When using the sealing film for sealing, it is arranged facing the support in a manner that clamps the photoelectric conversion device. There are no particular limitations on the shape, structure, size, or type of the substrate for the sealing film; it can be appropriately selected according to the purpose. The sealing film forms a barrier layer on the surface of the substrate to prevent the passage of moisture or oxygen; it can be formed on only one side of the substrate or on both sides.

[0200] The barrier layer may, for example, comprise a material primarily composed of a mixture of metal oxides, metals, polymers, and metal alkoxides. Examples of metal oxides include aluminum oxide, silicon oxide, and aluminum; examples of polymers include polyvinyl alcohol, polyvinylpyrrolidone, and methylcellulose; and examples of metal alkoxides include tetraethoxysilane, triisopropoxyaluminum, 3-glycidoxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanate-propyltriethoxysilane.

[0201] The barrier layer may be transparent or opaque. Furthermore, the barrier layer may be a single layer composed of the materials or a multi-layered structure. The barrier layer can be formed using known methods, such as vacuum film formation (e.g., sputtering), immersion coating, roll coating, screen printing, spray coating, photogravure printing, etc.

[0202] [Wiring]

[0203] To efficiently extract the current generated by light, the photoelectric conversion element 10 (e.g., a solar cell) of this embodiment is preferably connected to leads (wiring) on ​​the back electrodes of the first electrode 12 and the second electrode. The leads are connected to the first and second electrodes using conductive materials such as solder, silver paste, or graphite. The conductive material can be used alone, or a mixture of two or more, or in a laminated structure. Furthermore, from the viewpoint of physical protection, the area where the leads are mounted can also be covered with acrylic resin or epoxy resin.

[0204] Lead wires are a general term for wires used to electrically connect power sources or electronic components in circuits. Examples include plastic-coated wires and enameled wires.

[0205] The photoelectric conversion element 10 described above has excellent photoelectric conversion characteristics and improved durability.

[0206] [application]

[0207] The application and usage of the photoelectric conversion element 10 in this embodiment are not particularly limited, and it can be widely used for the same purposes as general photoelectric conversion elements (such as general solar cells). The photoelectric conversion element (e.g., solar cell) of this embodiment can be combined with a circuit board for controlling the generated current to be applied to a power supply device. Examples of devices utilizing this power supply device include electronic desktop computers and solar-powered radio-controlled watches. Furthermore, the solar cell of this embodiment can also be used as a power supply device in mobile phones, electronic paper devices, thermometers, hygrometers, etc. Additionally, by combining it with an auxiliary power supply for extending the continuous use time of rechargeable or dry-cell battery-powered electrical appliances, or a secondary battery, it can be used for nighttime use. Furthermore, it can also be used as a self-contained power source that does not require battery replacement or power wiring.

[0208] [Solar Cell Module]

[0209] The solar cell module of the embodiment includes the photoelectric conversion element 10 as described above. The specific structure of the solar cell module will be described in the embodiments.

[0210] The embodiments of the present invention have been described above, but these are merely examples of the present invention, and various other structures may also be employed.

[0211] In the photoelectric conversion element 10, an intermediate layer may be formed between the first electrode 12 and the hole transport layer 13. The intermediate layer is preferably formed of a single or mixed oxide of an oxide such as nickel, copper, or aluminum, which are p-type metal oxide semiconductors. The intermediate layer is preferably formed of nickel oxide (NiO).

[0212] The thickness of the intermediate layer is preferably 1 nm to 1000 nm, more preferably 10 nm to 500 nm. The method for forming the intermediate layer, which includes nickel oxide (NiO) as a p-type metal oxide semiconductor, is not particularly limited and can be any of vacuum film formation such as sputtering or ion plating, or wet film formation such as sol-gel. The average particle size of the nickel oxide particles is, for example, 0.2 nm to 60.0 nm, preferably 1.0 nm to 30.0 nm, more preferably 1.0 nm to 10.0 nm, and even more preferably 2.0 nm to 3.5 nm.

[0213] By forming an intermediate layer containing a p-type metal oxide semiconductor, the photoelectric conversion characteristics can be maintained without compromising the properties of the hole transport layer 13 and the insulating compound, while improving the durability of the photoelectric conversion element.

[0214] Example

[0215] The following describes embodiments of the present invention. However, the present invention is not limited to the following embodiments.

[0216] [Example 1]

[0217] A solar cell, which serves as a photoelectric conversion element, is fabricated in the following manner (film formation process 1).

[0218] On an ITO glass substrate (a substrate on which the first electrode is formed, with a square dimension of 25 mm), 1 mL of a solution of dimethylformamide (DMF) containing (A-06) (0.1 mmol / L) is placed, and a monolayer (hole transporter in the hole transport layer) is formed on the ITO (first electrode) using a spin coater (3,000 rpm, 30 seconds) and a heating plate (110°C, 10 minutes).

[0219] Next, using a spin coater (3,000 rpm, 30 seconds) and a heating plate (100°C, 15 minutes), 0.1 mL of a solution prepared by diluting an alumina dispersion (an alumina dispersion with an average particle size of 50 nm, an alumina content of 20 wt%, and 2-propanol as the dispersion medium) with 2-propanol to a ratio of 50 to 1 was added to the hole transporter. Thus, a hole transport layer was formed using a material that mixes hole transport material and insulating compound.

[0220] 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 spin-coated onto the aforementioned substrate. Spin-coating was performed at 3000 rpm, with chlorobenzene (0.3 mL) added dropwise 30 seconds after the start. The substrate was then heated at 150 °C for 10 minutes to obtain a perovskite layer (photoelectric conversion layer). Subsequently, a 0.5 nm layer of ethylenediamine dihydroiodate (interface layer) and C2O3 were deposited by vacuum evaporation. 60 A photoelectric conversion element was fabricated by forming a 20 nm (electron transport layer), a copper-based polymer (BCP, 8 nm) (electron injection layer), and a 100 nm Ag (second electrode) film. The solar cell characteristics of the 25 mm² square photoelectric conversion element were then evaluated.

[0221] In addition, to evaluate the fluctuations, 10 solar cells were fabricated under the same conditions, and their characteristics were evaluated. The best data (the best values) and the average and standard deviation of these 10 fabricated samples are shown in Table 1 (this is also true in the subsequent examples and comparative examples).

[0222] The photoelectric conversion characteristics of the photoelectric conversion element fabricated in Example 1 were measured according to the method for measuring the output of silicon-based solar cell cells as described in Japanese Industrial Standards (JIS) C8913:1998. A solar simulator (SMO-250III type manufactured by Spectrometer Co., Ltd.) equipped with an air quality filter equivalent to AM 1.5 G was used, and the output was adjusted to 100 mW / cm² using a secondary reference Si solar cell. 2 The light intensity was used as the light source for measurement. While irradiating the test sample of the perovskite solar cell (the photoelectric conversion element prepared in Example 1) with light, the IV curve characteristics were measured using a source meter (a 2400 general-purpose source meter manufactured by Keithley Instruments Inc.). The short-circuit current (Isc), open-circuit voltage (Voc), and fill factor (FF) obtained from the IV curve characteristics measurement were calculated. Then, the short-circuit current density (Jsc) and photoelectric conversion efficiency (PCE) were calculated.

[0223] The characteristics of the solar cells were also evaluated in the subsequent embodiments and comparative examples.

[0224] Equation 1: Short-circuit current density (Jsc; mA / cm²) 2 = Isc (mA) / Effective light-receiving surface S (cm) 2 )

[0225] Equation 2: Photoelectric conversion efficiency (PCE; %) = Voc (V) × Jsc (mA / cm) 2 )×FF×100 / 100 (mW / cm 2 )

[0226] [Example 2]

[0227] Except that the solution prepared by diluting the alumina dispersion (with an average particle size of 50 nm, an alumina content of 20 wt%, and 2-propanol as the dispersion medium) as the insulating compound in Example 1 to 2-propanol diluted 50 times, the solution was prepared by diluting the alumina dispersion (with an average particle size of 50 nm, an alumina content of 20 wt%, and 2-propanol as the dispersion medium) to 2-propanol diluted 30 times, the photoelectric conversion element was prepared in the same manner as in Example 1, and the photoelectric conversion efficiency was measured. The results of the solar cell characteristics are shown in Table 1 below.

[0228] [Example 3]

[0229] Except that the solution prepared by diluting the alumina dispersion (with an average particle size of 50 nm, an alumina content of 20 wt%, and 2-propanol as the dispersion medium) as the insulating compound in Example 1 to 50 times with 2-propanol was changed to a solution prepared by diluting the alumina dispersion (with an average particle size of 50 nm, an alumina content of 20 wt%, and 2-propanol as the dispersion medium) to 1000 times with 2-propanol, the photoelectric conversion element was prepared in the same manner as in Example 1, and the photoelectric conversion efficiency was measured. The results of the solar cell characteristics are shown in Table 1 below.

[0230] [Example 4]

[0231] Except that the DMF solution containing (A-06) (0.1 mmol / L) in Example 1 was replaced with the DMF solution containing (A-15) (0.1 mmol / L), the photoelectric conversion element was fabricated in the same manner as in Example 1, and the photoelectric conversion efficiency was measured. The results of the solar cell characteristics are shown in Table 1 below.

[0232] [Example 5]

[0233] Except that the DMF solution containing (A-06) (0.1 mmol / L) in Example 1 was replaced with a DMF solution containing (A-16) (0.1 mmol / L), the photoelectric conversion element was fabricated in the same manner as in Example 1, and the photoelectric conversion efficiency was measured. The results of the solar cell characteristics are shown in Table 1 below.

[0234] [Example 6]

[0235] Except that the DMF solution containing (A-06) (0.1 mmol / L) in Example 1 was changed to a DMF solution containing (A-06) (0.1 mmol / L) and 4-hydroxyphenylphosphonic acid (0.2 mmol / L), the photoelectric conversion element was fabricated in the same manner as in Example 1, and the photoelectric conversion efficiency was measured. The results of the solar cell characteristics are shown in Table 1 below.

[0236] [Example 7]

[0237] Except that the solution prepared by diluting the alumina dispersion (with an average particle size of 50 nm, an alumina content of 20 wt%, and 2-propanol as the dispersion medium) as the insulating compound in Example 1 to 50 times with 2-propanol was changed to a solution prepared by diluting the silica dispersion (with an average particle size of 150 nm, a silica content of 5 wt%, and ethanol as the dispersion medium) to 8 times with 2-propanol, the photoelectric conversion element was prepared in the same manner as in Example 1, and the photoelectric conversion efficiency was measured. The results of the solar cell characteristics are shown in Table 1 below.

[0238] [Example 8]

[0239] Except that the solution prepared by diluting the alumina dispersion (with an average particle size of 50 nm, an alumina content of 20 wt%, and 2-propanol as the dispersion medium) as the insulating compound in Example 1 with 2-propanol diluted 50 times, was replaced with a solution prepared by diluting the cerium oxide dispersion (with an average particle size of 50 nm, a cerium oxide content of 20 wt%, and 2.5 wt% aqueous acetic acid as the dispersion medium) with 2-propanol diluted 50 times, the photoelectric conversion element was prepared in the same manner as in Example 1, and the photoelectric conversion efficiency was measured. The results of the solar cell characteristics are shown in Table 1 below.

[0240] [Example 9]

[0241] Except that the solution prepared by diluting the alumina dispersion (with an average particle size of 50 nm, an alumina content of 20 wt%, and 2-propanol as the dispersion medium) as the insulating compound in Example 1 to 50 times with 2-propanol was changed to a solution prepared by diluting the yttrium oxide dispersion (with an average particle size of 100 nm, a yttrium oxide content of 10 wt%, and 2-propanol as the dispersion medium) to 25 times with 2-propanol, the photoelectric conversion element was prepared in the same manner as in Example 1, and the photoelectric conversion efficiency was measured. The results of the solar cell characteristics are shown in Table 1 below.

[0242] [Example 10]

[0243] Except that the solution prepared by diluting the alumina dispersion (with an average particle size of 50 nm, an alumina content of 20 wt%, and 2-propanol as the dispersion medium) as the insulating compound in Example 1 to 50 times with 2-propanol was changed to a solution prepared by diluting the barium titanate dispersion (with an average particle size of 50 nm, a barium titanate content of 5 wt%, and 2-propanol as the dispersion medium) to 12.5 times with 2-propanol, the photoelectric conversion element was prepared in the same manner as in Example 1, and the photoelectric conversion efficiency was measured. The results of the solar cell characteristics are shown in Table 1 below.

[0244] [Example 11]

[0245] A solar cell, which serves as a photoelectric conversion element, is fabricated in the following manner (film formation process 2).

[0246] On an ITO glass substrate (a substrate with a first electrode formed on a glass substrate serving as a support, 25 mm square), 0.1 mL of a solution prepared by diluting an alumina dispersion (an alumina dispersion with an average particle size of 50 nm, an alumina content of 20 wt%, and 2-propanol as the dispersion medium) 50 times with 2-propanol was placed. The solution was then treated with a spin coater (3,000 rpm, 30 seconds) and dried using a hot plate (100°C, 15 minutes). Next, 1 mL of a DMF solution containing (A-06) (0.1 mmol / L) was placed, and a hole transport layer was formed using a spin coater (3,000 rpm, 30 seconds) and a hot plate (110°C, 10 minutes). Next, a solution of cesium iodide (0.738 g), formamidinium 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 spin-coated onto the aforementioned substrate to form a film. Spin-coating was performed at 3000 rpm, with chlorobenzene (0.3 mL) added dropwise 30 seconds after the start. Afterward, heating at 150 °C for 10 minutes yielded a perovskite layer (photoelectric conversion layer). Subsequently, a 0.5 nm layer of ethylenediamine dihydroiodate (interface layer) and C2O3 were deposited by vacuum evaporation. 60 A photoelectric conversion element was fabricated by forming a 20 nm (electron transport layer), a copper-based polymer (BCP, 8 nm) layer (electron injection layer), and a 100 nm Ag layer (second electrode). The solar cell characteristics of the 25 mm² square photoelectric conversion element were evaluated. Its performance is shown in Table 1.

[0247] [Example 12]

[0248] Except that the solution prepared by diluting the alumina dispersion (alumina with an average particle size of 50 nm, an alumina content of 20 wt%, and 2-propanol as the dispersion medium) with 2-propanol to a concentration of 50 times was changed in Example 11 to a solution prepared by diluting the silica dispersion (silica with an average particle size of 150 nm, a silica content of 5 wt%, and ethanol as the dispersion medium) with 2-propanol to a concentration of 8 times, the photoelectric conversion element was fabricated in the same manner as in Example 11, and the photoelectric conversion efficiency was measured. The results of the solar cell characteristics are shown in Table 1 below.

[0249] [Example 13]

[0250] Solar cells, which serve as photoelectric conversion elements, are fabricated in the following manner (film formation process 3).

[0251] On an ITO glass substrate (a substrate with a first electrode formed on a glass substrate serving as a support, measuring 25 mm square), 1 mL of a solution prepared by diluting an alumina dispersion (alumina with an average particle size of 50 nm, an alumina content of 20 wt%, and a dispersion medium of 2-propanol) with DMF to a concentration of 50 times with DMF and a DMF solution containing (A-15) (0.1 mmol / L) at a volume ratio of 1:1 was placed. A hole transport layer was formed using a spin coater (3,000 rpm, 30 seconds) and a heating plate (110°C, 10 minutes). Next, a solution of cesium iodide (0.738 g), formamidinium 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 spin-coated onto the aforementioned substrate to form a film. Spin-coating was performed at 3000 rpm, with chlorobenzene (0.3 mL) added dropwise 30 seconds after the start. Afterward, heating at 150 °C for 10 minutes yielded a perovskite layer (photoelectric conversion layer). Subsequently, a 0.5 nm layer of ethylenediamine dihydroiodate (interface layer) and C2O3 were deposited by vacuum evaporation. 60 A photoelectric conversion element was fabricated by forming a 20 nm (electron transport layer), a copper-based polymer (BCP, 8 nm) layer (electron injection layer), and a 100 nm Ag layer (second electrode). The solar cell characteristics of the 25 mm² square photoelectric conversion element were evaluated. Its performance is shown in Table 1.

[0252] [Example 14]

[0253] Except that the solution prepared by diluting the alumina dispersion (with an average particle size of 50 nm, an alumina content of 20 wt%, and 2-propanol as the dispersion medium) as the insulating compound in Example 1 to 50 times with 2-propanol was changed to a solution prepared by mixing the alumina dispersion (with an average particle size of 50 nm, an alumina content of 20 wt%, and 2-propanol as the dispersion medium) to 50 times with 2-propanol and the silica dispersion (with an average particle size of 150 nm, a silica content of 5 wt%, and ethanol as the dispersion medium) to 8 times with 2-propanol at a mass ratio of 1:1, the photoelectric conversion element was prepared in the same manner as in Example 1, and the photoelectric conversion efficiency was measured. The results of the solar cell characteristics are shown in Table 1 below.

[0254] [Example 15]

[0255] Except that the solution prepared by diluting the alumina dispersion (with an average particle size of 50 nm, an alumina content of 20 wt%, and 2-propanol as the dispersion medium) as the insulating compound in Example 1 to 50 times with 2-propanol was changed to a solution prepared by mixing the alumina dispersion (with an average particle size of 50 nm, an alumina content of 20 wt%, and 2-propanol as the dispersion medium) to 50 times with 2-propanol and the yttrium oxide dispersion (with an average particle size of 100 nm, a yttrium oxide content of 10 wt%, and 2-propanol as the dispersion medium) to 25 times with 2-propanol at a volume ratio of 1:1, the photoelectric conversion element was prepared in the same manner as in Example 1, and the photoelectric conversion efficiency was measured. The results of the solar cell characteristics are shown in Table 1 below.

[0256] [Comparative Example 1]

[0257] Except for not using the solution prepared by diluting the alumina dispersion (with an average particle size of 50 nm, an alumina content of 20 wt%, and 2-propanol as the dispersion medium) as an insulating compound with 2-propanol to a concentration of 50 times in Example 1, the photoelectric conversion element was fabricated in the same manner as in Example 1, and the photoelectric conversion efficiency was measured. The results of the solar cell characteristics are shown in Table 1 below.

[0258] [Comparative Example 2]

[0259] Except that the solution prepared by diluting the alumina dispersion (with an average particle size of 50 nm, an alumina content of 20 wt%, and 2-propanol as the dispersion medium) as the insulating compound in Example 1 to 50 times with 2-propanol was changed to a solution prepared by diluting the aluminum-doped zinc oxide dispersion (with an average particle size of 16 nm, an AZO content of 2.5 wt%, and 2-propanol as the dispersion medium) to 6.25 times with 2-propanol, the photoelectric conversion element was fabricated in the same manner as in Example 1, and the photoelectric conversion efficiency was measured. The results of the solar cell characteristics are shown in Table 1 below.

[0260] [Comparative Example 3]

[0261] Except that the solution prepared by diluting the alumina dispersion (with an average particle size of 50 nm, an alumina content of 20 wt%, and 2-propanol as the dispersion medium) as the insulating compound in Example 11 to 50 times with 2-propanol was changed to a solution prepared by diluting the aluminum-doped zinc oxide dispersion (with an average particle size of 16 nm, an AZO content of 2.5 wt%, and 2-propanol as the dispersion medium) to 6.25 times with 2-propanol, the photoelectric conversion element was fabricated in the same manner as in Example 11, and the photoelectric conversion efficiency was measured. The results of the solar cell characteristics are shown in Table 1 below.

[0262] [Comparative Example 4]

[0263] Except that the solution prepared by diluting the alumina dispersion (with an average particle size of 50 nm, an alumina content of 20 wt%, and a dispersion medium of 2-propanol) as the insulating compound to DMF 50 times in Example 13 was changed to a solution prepared by diluting the aluminum-doped zinc oxide dispersion (with an average particle size of 16 nm, an AZO content of 2.5 wt%, and a dispersion medium of 2-propanol) to DMF 6.25 times, the photoelectric conversion element was fabricated in the same manner as in Example 13, and the photoelectric conversion efficiency was measured. The results of the solar cell characteristics are shown in Table 1 below.

[0264] [Table 1]

[0265]

[0266] As can be seen from the comparison between Example 1 and Comparative Example 1 in Table 1, high efficiency is achieved by using a material that mixes hole transport materials and insulating compounds in the hole transport layer, particularly by increasing the short-circuit current density (Jsc). Furthermore, Examples 1 to 3 demonstrate that high efficiency is achieved even when the concentration of the insulating compound varies, and Examples 7 to 10 demonstrate that high-efficiency solar cells can be provided even when the types of insulating compounds are different. Additionally, Examples 1 and Examples 4 to 5 demonstrate that high-output solar cells can be provided when combined with insulating compounds, even when the types of hole transport materials are different.

[0267] Furthermore, it is evident from Examples 1 and 11-13 that high output can be achieved even by changing the film formation method. As can be seen from Examples 1 and Comparative Examples 2, 11 and Comparative Examples 3, and 13 and Comparative Examples 4, high-output solar cells can be obtained when the material combined with the hole transport material is an insulating compound. However, if it is combined with a conductive compound (AZO, typically shown as 10...),... -3A combination of resistance values ​​(Ω / □) can only provide low-efficiency solar cells. Furthermore, it is evident that not only do the solar cells exhibit high performance, but the present invention also demonstrates excellent performance in terms of the fluctuation (standard deviation) of solar cell performance when 10 solar cells are manufactured.

[0268] [Example 16]

[0269] Nickel oxide (NiO) was sputtered to a thickness of 15 nm onto an ITO glass substrate (a substrate with the first electrode formed on the glass substrate serving as a support, 25 mm square). Then, a 1 mL solution of DMF containing (A-06) (0.1 mmol / L) was placed on the NiO and a monolayer (hole transport layer) was formed using a spin coater (3,000 rpm, 30 seconds) and a heated plate (110°C, 10 minutes). Next, a hole transport layer was formed using a spin coater (3,000 rpm, 30 seconds) and a heated plate (100°C, 15 minutes) to prepare a solution of alumina dispersion (Sigma Aldrich, 702129, 50 nm, 20 wt%, 2-propanol dispersion) diluted 50 times with 2-propanol. Next, a solution of cesium iodide (0.738 g), formamidinium 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 spin-coated onto the aforementioned substrate to form a film. Spin-coating was performed at 3000 rpm, with chlorobenzene (0.3 mL) added dropwise 30 seconds after the start. Afterward, heating at 150 °C for 10 minutes yielded a perovskite layer (photoelectric conversion layer). Subsequently, a 0.5 nm layer of ethylenediamine dihydroiodate (interface layer) and C2O3 were deposited by vacuum evaporation. 60 A photoelectric conversion element was fabricated using a film consisting of a 20 nm (electron transport layer), a copper-based polymer (BCP, 8 nm) layer (electron injection layer), and a 100 nm Ag electrode. The solar cell characteristics of the 25 mm² square photoelectric conversion element were evaluated. Its performance is shown in Table 1. Furthermore, to evaluate fluctuations, 10 solar cells were fabricated under the same conditions, and their characteristics were evaluated, along with the mean and standard deviation. These values ​​are shown in Table 2.

[0270] [Example 17]

[0271] Except for changing the NiO (15 nm film thickness) in Example 16 to NiO (25 nm film thickness), the photoelectric conversion element was fabricated in the same manner as in Example 16, and the photoelectric conversion efficiency was measured. The results of the solar cell characteristics are shown in Table 2 below.

[0272] [Example 18]

[0273] Except for changing the NiO (15 nm film thickness) in Example 16 to NiO (50 nm film thickness), the photoelectric conversion element was fabricated in the same manner as in Example 16, and the photoelectric conversion efficiency was measured. The results of the solar cell characteristics are shown in Table 2 below.

[0274] [Example 19]

[0275] Except for changing the NiO (15 nm film thickness) in Example 16 to NiO (70 nm film thickness), the photoelectric conversion element was fabricated in the same manner as in Example 16, and the photoelectric conversion efficiency was measured. The results of the solar cell characteristics are shown in Table 2 below.

[0276] [Example 20]

[0277] Except that the NiO (15 nm film thickness) in Example 16 was replaced with CuAlO2 (15 nm film thickness), the photoelectric conversion element was fabricated in the same manner as in Example 16, and the photoelectric conversion efficiency was measured. The results of the solar cell characteristics are shown in Table 2 below.

[0278] [Example 21]

[0279] Except that the NiO (15 nm film thickness) in Example 16 was replaced with CuAlO2 (30 nm film thickness), the photoelectric conversion element was fabricated in the same manner as in Example 16, and the photoelectric conversion efficiency was measured. The results of the solar cell characteristics are shown in Table 2 below.

[0280] [Example 22]

[0281] Except that the NiO (15 nm film thickness) in Example 16 was replaced with CuAlO2 (50 nm film thickness), the photoelectric conversion element was fabricated in the same manner as in Example 16, and the photoelectric conversion efficiency was measured. The results of the solar cell characteristics are shown in Table 2 below.

[0282] [Example 23]

[0283] Except that the NiO (15 nm film thickness) in Example 16 was replaced with CuAlO2 (70 nm film thickness), the photoelectric conversion element was fabricated in the same manner as in Example 16, and the photoelectric conversion efficiency was measured. The results of the solar cell characteristics are shown in Table 2 below.

[0284] [Example 24]

[0285] Except that the NiO (15 nm film thickness) in Example 16 was replaced with NiAlO2 (15 nm film thickness), the photoelectric conversion element was fabricated in the same manner as in Example 16, and the photoelectric conversion efficiency was measured. The results of the solar cell characteristics are shown in Table 2 below.

[0286] [Table 2]

[0287]

[0288] As described above, this embodiment confirms that by using the hole transport material of the above-described form and the insulating compound in the hole transport layer, not only can the characteristics of the solar cell be improved, but also the characteristic fluctuations can be reduced.

[0289] [Solar Cell Module]

[0290] A first electrode 42 is formed on the surface of a glass substrate 41, and a laser processing device is used to pattern the first electrode 42. Figure 2 The shape is shown. A monomolecular hole transport layer is formed on the first electrode 42, further obtaining a perovskite layer as a photoelectric conversion layer. Subsequently, an electron transport layer is deposited by vacuum evaporation. Afterwards, the photoelectric conversion layer (perovskite layer) is etched using a laser processing device, forming the shape shown. Figure 3 The pattern of the photoelectric conversion layer (perovskite layer) 43 is shown. Finally, 70 nm Ag was formed by vacuum evaporation, and the second electrode 44 was etched using a laser processing device to obtain the desired result. Figure 4 and Figure 5 Photovoltaic conversion module (perovskite solar cell module) of the shape shown.

[0291] The present invention has been described above using the embodiments and examples. However, the present invention is not limited to the embodiments and examples described above. Without departing from the spirit of the present invention, it can be arbitrarily and appropriately combined, modified, or selectively used as needed.

[0292] Industrial availability

[0293] As explained above, the photoelectric conversion element of the present invention can be effectively used as a solar cell, for example. The application and method of use of the photoelectric conversion element of the present invention are not particularly limited; for example, it can be applied to a wide range of fields with the same applications and methods as general photoelectric conversion elements (e.g., general solar cells).

[0294] Cross-reference of related applications

[0295] This application claims priority based on Japanese Patent Application No. 2023-198632 filed with the Japan Patent Office on November 22, 2023, the entire disclosure of which is incorporated herein by reference.

[0296] Explanation of icon numbers

[0297] 10: Photoelectric conversion element

[0298] 11: Support

[0299] 12: First electrode

[0300] 13: Hole transport layer

[0301] 14: Photoelectric conversion layer

[0302] 15: Electron transport layer

[0303] 16: Second electrode

Claims

1. A photoelectric conversion element, characterized in that, The first electrode, hole transport layer, photoelectric conversion layer, and second electrode are stacked directly or indirectly in this order. The photoelectric conversion layer contains a perovskite compound. The hole transport layer comprises an insulating compound in contact with the main surface of the first electrode on the side of the photoelectric conversion layer, and a compound represented by the following chemical formula (I). Ar 1 -(L 1 -X 1 )n...(I) In the chemical formula (I), Ar 1 For a structure containing an aromatic ring, heteroatoms may be included among the atoms constituting the aromatic ring, Ar 1 It can have the function of -L 1 -X 1 Other substituents; n is an integer greater than or equal to 1, and -L is used when n is greater than or equal to 2. 1 -X 1 The structures represented can be the same or different from each other; L 1 To make Ar 1 With X 1 The bond consists of a divalent linker or a single bond; X 1 It is a group that can form chemical bonds or hydrogen bonds with the first electrode.

2. The photoelectric conversion element according to claim 1, wherein, The hole transport layer comprises a compound represented by the following chemical formula (II), HAS 1 -L 2 -X 2 ..(II) A 1 A group comprising one or more substituents or structures selected from the group consisting of alkoxy, hydroxy, carboxyl, dihydroxyphosphoryl, dialkylphosphoryl, hydroxysulfonyl, amino, monoalkylamino, dialkylamino, monoarylamino, diarylamino, monoalkylaminocarbonyl, dialkylaminocarbonyl, alkylcarbonyloxy, alkoxycarbonyl, aminocarbonyl, aminocarbonylamino, alkylcarbonylamino, alkylsulfonylamino, aminosulfonyl, and nitrogen-containing heterocyclic groups; L 2 To make A 1 With X 2 The bond consists of a divalent linker or a single bond; X 2 It is a group that can form chemical bonds or hydrogen bonds with the first electrode.

3. The photoelectric conversion element according to claim 1 or 2, wherein, The compound represented by the chemical formula (I) forms a monolayer.

4. The photoelectric conversion element according to claim 1 or 2, wherein, The insulating compound is selected from at least one of metal oxides, metal nitrides, insulating organic compounds, and organic-inorganic hybrid compounds.

5. The photoelectric conversion element according to claim 4, wherein, The insulating compound is in particle shape.

6. The photoelectric conversion element according to claim 5, wherein, The average particle size of the insulating compound is in the range of 1 nm to 200 nm.

7. The photoelectric conversion element according to claim 1 or 2, wherein, X in the chemical formula (I) 1 The groups selected are respectively free from dihydroxyphosphoryl (-P=O(OH)2), carboxyl (-COOH), sulfonyl (-SO3H), borate (-B(OH)2), trihalosilyl (-SiX3, where X is a halogenated group), trialkoxysilyl (-Si(OR)3, where R is an alkyl group), trihydroxysilyl, and dialkylphosphoryl.

8. The photoelectric conversion element according to claim 2, wherein, X in chemical formula (II) 2 The groups are independently selected from the group consisting of dihydroxyphosphoryl (-P=O(OH)2), carboxyl (-COOH), sulfonyl (-SO3H), borate (-B(OH)2), trihalosilyl (-SiX3, where X is a halogenated group), trialkoxysilyl (-Si(OR)3, where R is an alkyl group), trihydroxysilyl, and dialkylphosphoryl.

9. The photoelectric conversion element according to claim 1 or 2, wherein, The perovskite compound is an organic-inorganic perovskite compound.

10. The photoelectric conversion element according to claim 1 or 2, wherein, The mass ratio of the compound represented by chemical formula (I) to the mass of the insulating compound (m2) satisfies the following equation (A). m1 / m2=1 / 10~1 / 20000 (A).

11. The photoelectric conversion element according to claim 1 or 2, wherein, An intermediate layer containing nickel oxide is formed between the first electrode and the hole transport layer.

12. A solar cell module comprising the photoelectric conversion element as described in claim 1 or 2.

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