Photoelectric conversion element and photoelectric conversion device

Abstract

To provide a photoelectric conversion element with improved durability when the element is driven. [Solution] A photoelectric conversion element comprising a first electrode, a second electrode, a photoelectric conversion layer containing a perovskite structure crystal disposed between the first electrode and the second electrode, and an electron transport layer disposed between the second electrode and the photoelectric conversion layer, wherein the electron transport layer contains a cured product of a composition containing an organic electron transport compound having polymerizable functional groups that can react with isocyanate groups and a crosslinking agent, the crosslinking agent being a bifunctional isocyanate compound, and the molecular weight of the portion of the crosslinking agent excluding the isocyanate group and the blocked isocyanate group being 14 or more and 330 or less.

Description

[Technical Field]

[0001] This disclosure relates to a photoelectric conversion element and a photoelectric conversion device. [Background technology]

[0002] In order to address the depletion of fossil fuels and the environmental problems caused by their use, research is actively being conducted on renewable and clean alternative energy sources such as solar, wind, and hydroelectric power.

[0003] Among these, there is growing interest in solar cells, which directly convert sunlight into electrical energy. Here, a solar cell is a battery that absorbs light energy from sunlight and generates current-voltage by utilizing the photovoltaic effect, which generates electrons and holes.

[0004] Currently, np diode type silicon (Si) single-crystal based solar cells with light energy conversion efficiencies exceeding 20% ​​are widely known and actually used in photovoltaic power generation. However, these have the problem of high cost per unit of power due to the need for high-temperature processing and the high price of the material itself. Furthermore, there are supply issues from the perspective of silicon resources.

[0005] On the other hand, solar cells using organic materials (hereinafter referred to as "organic solar cells") do not require high-temperature processing and can be produced using a so-called roll-to-roll method on sheet substrates, which is expected to reduce costs.

[0006] However, further improvements in power generation efficiency and durability are desired for the practical application of organic solar cells. In particular, perovskite solar cells, which have a perovskite structure crystal as the photoelectric conversion layer, are being developed towards practical application because of their excellent photoelectric conversion characteristics.

[0007] For example, Patent Document 1 describes a technology that exhibits excellent conversion efficiency by using a cured product obtained by polymerizing perylenediimide compounds, naphthalenediimide compounds, etc., with a crosslinking agent and a resin.

[0008] Patent Document 2 describes a technique for forming a cured product consisting of fullerene or its derivative, a crosslinking agent, and one or more polymers on the surface or interface of a perovskite material layer in a photovoltaic device such as a perovskite solar cell. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2022-2293 [Patent Document 2] Japanese Patent Publication No. 2025-129149 [Overview of the project] [Problems that the invention aims to solve]

[0010] According to the inventors' investigations, it was found that the photoelectric conversion elements described in Patent Document 1 and Patent Document 2 have room for improvement in their characteristics after repeated thermal and light durability tests.

[0011] Therefore, the object of this disclosure is to provide a photoelectric conversion element with improved durability in repeated thermal and light endurance tests. [Means for solving the problem]

[0012] The above objectives are achieved by the following disclosure. That is, this disclosure is: A photoelectric conversion element comprising a first electrode, a second electrode, a photoelectric conversion layer containing a perovskite crystal disposed between the first electrode and the second electrode, and an electron transport layer disposed between the second electrode and the photoelectric conversion layer, The electron transport layer contains a cured product of a composition comprising an organic electron transport compound having a polymerizable functional group that can react with an isocyanate group, and a crosslinking agent. The crosslinking agent is a bifunctional isocyanate compound, The photoelectric conversion element is characterized in that the molecular weight of the portion of the crosslinking agent excluding the isocyanate group and the blocked isocyanate group is between 14 and 330. Furthermore, this disclosure relates to a photoelectric conversion device equipped with the above-mentioned photoelectric conversion element. [Effects of the Invention]

[0013] According to this disclosure, it is possible to provide a photoelectric conversion element with improved durability in repeated thermal and light endurance tests. [Brief explanation of the drawing]

[0014] [Figure 1] This is an example of a schematic cross-sectional view in the thickness direction of one embodiment of the photoelectric conversion element disclosed herein. [Figure 2] This is a schematic perspective view showing an example of an embodiment of a mobile body equipped with a photoelectric conversion element of the present disclosure. [Figure 3] This is a schematic perspective view showing an example of an embodiment of a building material equipped with a photoelectric conversion element according to the present disclosure. [Modes for carrying out the invention]

[0015] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings, but the present disclosure is not limited thereto.

[0016] <One Embodiment> One embodiment relates to a photoelectric conversion element. The photoelectric conversion element disclosed herein is A photoelectric conversion element comprising a first electrode, a second electrode, a photoelectric conversion layer containing a perovskite crystal disposed between the first electrode and the second electrode, and an electron transport layer disposed between the second electrode and the photoelectric conversion layer, The electron transport layer contains a cured product of a composition comprising an organic electron transport compound having a polymerizable functional group that can react with an isocyanate group, and a crosslinking agent. The crosslinking agent is a bifunctional isocyanate compound, The crosslinking agent is characterized in that the molecular weight of the portion excluding the isocyanate group and the blocked isocyanate group is between 14 and 330.

[0017] As a result of their investigation, the inventors have found that the above configuration results in a photoelectric conversion element with excellent durability. In this disclosure, the reasons why a photoelectric conversion element with excellent durability in repeated thermal and light durability tests is obtained are not fully explained, but they are thought to be as follows.

[0018] As described in Patent Document 1, a technique has been known to improve solvent resistance and hardness and photoelectric conversion efficiency by using an electron transport layer that combines a polymerizable electron transport compound with a cured product of a trifunctional or more polyfunctional crosslinking agent, in order to prevent bias or changes in the constituent materials during film formation and use.

[0019] To further improve the properties, possible methods include reducing the proportion of crosslinking agents that are not electron-transporting compounds, increasing the proportion of electron-transporting compounds, or adding other functional materials.

[0020] Therefore, when we investigated by relatively reducing the molecular weight of polyfunctional crosslinking agents with three or more functions, we were able to obtain devices with improved solvent resistance and hardness, as well as excellent photoelectric conversion efficiency. However, another problem was discovered: deterioration of photoelectric conversion efficiency in repeated heat and light durability tests.

[0021] The repeated heat and light durability test is a durability test method that simulates the day and night environments in which photoelectric conversion elements are actually used. It evaluates durability by repeatedly subjecting them to light irradiation and high-temperature environments, and to environments without light irradiation and low-temperature environments.

[0022] In this repeated thermal and light endurance test, repeated exposure to and de-exposure of light easily induces degradation of each layer and component due to the accumulation and release of charge and fluctuations in the internal electric field. In this case, stress is applied due to the accumulation and release of stress caused by the difference in thermal expansion of each layer and component due to repeated exposure to high and low temperatures.

[0023] Electron transport layers containing cured materials generally exhibit high morphological stability because they form a network structure by chemically bonding molecules together, thereby suppressing molecular movement and rearrangement. However, reducing the molecular weight of polyfunctional crosslinking agents with three or more functions shortens the crosslinking point distance. This can lead to localized stress concentration due to repeated thermal expansion during repeated thermal and light durability tests, resulting in microcracks and delamination, which in turn create defects in the electron transport pathway and degrade the properties.

[0024] Based on the above assumptions, various methods were considered to prevent deterioration of photoelectric conversion efficiency during repeated thermal and light endurance tests, resulting in the configuration described in this disclosure.

[0025] It is believed that by using a bifunctional isocyanate compound as a low-molecular-weight crosslinking agent and forming a cured product with an organic electron-transporting compound having polymerizable functional groups that can react with isocyanate groups, the resulting structure will have more linear components, increasing flexibility and thus dispersing and easing stress concentration during thermal expansion.

[0026] However, simply reducing the number of crosslinking points tends to lower morphological stability, such as suppression of molecular movement and rearrangement, compared to the polyfunctional case, making it difficult to improve durability. By using an isocyanate compound as a bifunctional crosslinking agent, a -NHCO- bond is formed in the cured product of an organic electron transport compound having a polymerizable functional group that can react with the isocyanate group.

[0027] This bond site forms a significant dipole moment between the C=O group and the NH group. The NH group acts as a hydrogen bond donor, and the C=O group acts as an acceptor, making it easy for strong hydrogen bonds to form between these bond sites. This strong intermolecular force from the hydrogen bonds helps to ensure strength, such as suppressing molecular movement and rearrangement.

[0028] Therefore, this disclosure demonstrates that a film containing a cured organic electron-transport compound can achieve both flexibility and strength. Consequently, it is presumed that durability in repeated thermal and light resistance tests has been improved.

[0029] The electron transport layer of this disclosure contains a cured product of a composition comprising an organic electron transport compound having polymerizable functional groups that can react with isocyanate groups, and a crosslinking agent.

[0030] In this disclosure, an electron-transporting compound may be described as a compound that can efficiently transport electrons, as an N-type semiconductor compound, or as a compound whose Fermi level approaches the conduction band or lowest unoccupied orbital (LUMO).

[0031] Furthermore, in this disclosure, the electron transport layer may be described as a layer containing a cured product of a composition containing an electron transport compound that efficiently transports electrons, or a layer containing a cured product of a composition containing an N-type semiconductor compound, or a layer containing a cured product of a composition in which the Fermi level is close to the conduction band or the lowest unoccupied orbital (LUMO).

[0032] In this disclosure, it is preferable that the organic electron-transporting compound contains at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a thiol group, and a heteroatom.

[0033] Organic electron-transporting compounds have polymerizable functional groups that can react with isocyanate groups. If the polymerizable functional group contains at least one selected from the group consisting of hydroxyl groups, carboxyl groups, amino groups, and thiol groups, it polymerizes well with isocyanates and facilitates the formation of hydrogen bonds. It is more preferable to contain two functional groups, as this increases the number of linear structures and enhances flexibility.

[0034] As the organic electron-transporting compound, the non-fullerene derivative is preferably a compound selected from a phthalocyanine derivative, a triazine derivative, a phenanthroline derivative, a pyrene derivative, a perylenediimide derivative, a naphthalenediimide derivative, an azaacene derivative, and an indacenodithiophene derivative, and more preferably a compound selected from a perylenediimide derivative, a naphthalenediimide derivative, an azaacene derivative, and an indacenodithiophene derivative.

[0035] Further, in the present disclosure, it is still more preferable that the organic electron-transporting compound is at least one compound selected from the group consisting of a compound represented by the following formula (E1), a compound represented by the following formula (E2), a compound represented by the following formula (E3), and a compound represented by the following formula (E4).

Chemical Formula

Chemical Formula

Chemical Formula

Chemical Formula

[0036] In this disclosure, in formulas (E1) to (E4), R 11 ~R 20 , R 21 ~R 26 , R 31 ~R 34 , and R 41 ~R 48 Preferably, each of these is independently a group represented by the following formula (1). -(R a ) m -(R b ) n -R c (1) (In equation (1), m and n are independently either 0 or 1.) In formula (1), R a R in formula (1) represents an alkylene group having 1 to 10 substituted or unsubstituted carbon atoms, or an arylene group having 6 to 14 substituted or unsubstituted carbon atoms. c Or R in formula (2) below d They may be connected to each other to form a ring. In formula (1), R b represents an oxygen atom, a sulfur atom, or a group represented by the following formula (2). [ka] (In formula (2), R d R represents a hydrogen atom, or an alkyl group having 1 to 4 substituted or unsubstituted carbon atoms. In this case, R in formula (1) a or R in equation (1) c They may be connected to each other to form a ring. In formula (1), R c R represents a hydrogen atom, an alkyl group having 1 to 10 substituted or unsubstituted carbon atoms, an aryl group having 6 to 14 substituted or unsubstituted carbon atoms, or an arylalkyl group having 7 to 18 substituted or unsubstituted carbon atoms. In this case, R in formula (1) a or R in equation (2) d They may be connected to each other to form a ring. The substituents that the alkylene group and the alkyl group may have are a hydroxyl group, a carboxyl group, an amino group, a thiol group, an alkoxy group having 1 to 3 carbon atoms, and an alkoxycarbonyl group having 2 to 4 carbon atoms. The substituents that the arylene group, the aryl group, and the arylalkyl group may have are alkyl groups having 1 to 3 carbon atoms, hydroxyl groups, hydroxyalkyl groups having 1 to 3 carbon atoms, carboxyl groups, amino groups, thiol groups, alkoxy groups having 1 to 3 carbon atoms, alkoxycarbonyl groups having 2 to 4 carbon atoms, halogen atoms, cyano groups, and nitro groups. However, R 11 ~R 20 One or more of these are groups containing a functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a thiol group, R 21 ~R 26 One or more of these are groups containing a functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a thiol group, R 31 ~R 34 One or more of these are groups containing a functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a thiol group, R 41 ~R48 One or more of these groups contain a functional group selected from the group consisting of hydroxyl groups, carboxyl groups, amino groups, and thiol groups.

[0037] The ASA of electron-transporting compounds can approximate the molecular surface area while considering the exposure of each atom within the molecule. The ASA of electron-transporting compounds is calculated using the following equations (5) and (6). The ASA of electron-transporting compounds is 240 Å. 2 In cases exceeding 240 Å, 2 It may also be less than [a certain value].

[0038] In this disclosure, ASA is calculated in the following steps: Step 1: Obtaining the atomic radius The van der Waals radius R of each atom in the molecule i Calculate.

[0039] Step 2: Calculate the combination For each bond within the molecule, a scaling factor b is applied depending on the type of bond. ij Calculate.

[0040] Step 3: Calculation of atomic contributions Contribution A of each atom i i The contribution A of each atom i is calculated based on the following formula. i This value is obtained by subtracting a correction that takes into account the filling by nearby atoms j from the surface area in the case of isolation.

number

[0041] Step 4: Calculation of total surface area The ASA value can be calculated by summing the contributing surface areas of each atom.

number

[0042] The above calculations were performed using the Python language and the RDKit library (an open-source library for chemical informatics and chemical calculations). ASA can approximately estimate the molecular surface area while considering the exposure of each atom within the molecule.

[0043] Scaling factor b ij It is calculated by the following formula. Here, R i , R j The van deer Waals radii of atoms i and j, f bond (t) indicates a correction value corresponding to the type of bond t. The van deer Waals radius uses periodic table data defined in the rdkit.Chem.PeriodicTable module of Rdkit.

[0044] The LUMO level of electron-transporting compounds can be measured by cyclic voltammetry (CV). An example of measurement conditions is as follows: electrochemical analyzer ALS600F (BSA), DMF solvent, supporting electrolyte: tetrabutylammonium perchlorate, working electrode: glassy carbon electrode, reference electrode: silver-silver chloride electrode, auxiliary electrode: platinum electrode, sweep rate: 50 mV / s. The LUMO level is calculated from the half-wave potential of the measured redox potential and the vacuum level of the reference electrode.

[0045] The LUMO level of electron-transporting compounds can be below -3.70 eV or above -3.70 eV.

[0046] Examples of organic electron-transporting compounds include those shown in Tables 1 to 6.

[0047] [Table 1]

[0048] [Table 2]

[0049] [Table 3]

[0050] [Table 4]

[0051] [Table 5]

[0052] [Table 6]

[0053] Furthermore, from the viewpoint of passivation effect, organic electron-transporting compounds preferably contain heteroatoms with 6 to 20 atoms, and more preferably contain heteroatoms with 8 to 16 atoms.

[0054] From the viewpoint of achieving both charge transport properties and durability, the content of the organic electron-transporting compound in the composition is preferably 50% by mass or more and 90% by mass or less, relative to the total mass of solids in the composition. In other words, in this disclosure, when the total mass of solids in the composition is 100 parts by mass, the content of the organic electron-transporting compound in the composition is preferably 50 parts by mass or more and 90 parts by mass or less. In this disclosure, the content ratio can be confirmed by a nuclear magnetic resonance (NMR) spectrometer or a gas chromatograph-mass spectrometer (GC-MS), etc.

[0055] Crosslinking agents are generally compounds that do not contain electron-transporting structures. The crosslinking agents of this disclosure are difunctional isocyanate compounds. In this disclosure, difunctional means, for example, that the total number of isocyanate groups and blocked isocyanate groups is 2 per molecule.

[0056] A blocked isocyanate group refers to a structural portion formed when an isocyanate group is bonded to a blocking agent, such as an oxime. When heated, the blocking agent dissociates, and the isocyanate group is regenerated, allowing the polymerization reaction to proceed.

[0057] Here, the groups included in a bifunctional isocyanate compound are not limited to isocyanate groups and blocked isocyanate groups, but may also include chemically modified isocyanate groups that are bonded to some molecule or atom.

[0058] Examples of blocking agents include alcohol compounds, phenolic compounds, active methylene compounds such as ethyl acetate, acetylacetone, and diethyl malonate, mercaptan compounds such as butyl mercaptan and dodecyl mercaptan, acid amide compounds such as acetanilide and acetic acid amide, lactam compounds such as ε-caprolactam, δ-valerolactam, and γ-butyrolactam, acid imide compounds such as succinimide and maleimide, and imidazole compounds such as imidazole and 2-methylimidazole. Examples of blocking agents include pyrazole compounds such as 3,5-dimethylpyrazole, urea compounds such as urea, thiourea, and ethyleneurea, oxime compounds such as formamide oxime, acetaldehyde oxime, acetone oxime, methyl ethyl ketoxime, methyl isobutyl ketoxime, and cyclohexanone oxime, and amine compounds such as diphenylaniline, aniline, carbazole, ethyleneimine, and polyethyleneimine. These blocking agents can be used individually or in combination of two or more.

[0059] In this disclosure, the molecular weight of the portion of the crosslinking agent excluding the isocyanate group and the blocked isocyanate group is between 14 and 330. The molecular weight of the excluded portion, in the case of the isocyanate group, is, for example, the molecular weight of the structure * excluding the NCO portion in the structure shown below. OCN-*-NCO (* represents the other part of the crosslinking agent.)

[0060] In the case of blocked isocyanate groups, for example, the molecular weight is that of the structure * excluding the -NHCO-B (blocked isocyanate group) which is formed by the bonding of the isocyanate group and the blocking agent in the structure shown below. B-OCHN-*-NHCO-B (B represents the blocking agent, and * represents the other parts of the crosslinking agent.)

[0061] When the molecular weight of the crosslinking agent is small, even if the content of organic electron-transporting compounds increases, it is easier to form an electron-transport layer containing a cured product with high strength due to the bonding. It is preferable that the molecular weight of the portion of the crosslinking agent excluding the isocyanate group and blocked isocyanate group is 330 or less, as this makes it easier to form an electron-transport layer containing a cured product with high strength due to the bonding, even if the content of organic electron-transporting compounds increases.

[0062] In this disclosure, it is preferable that the molecular weight of the portion of the crosslinking agent excluding the isocyanate group and the blocked isocyanate group is between 14 and 160. A molecular weight of 160 or less of the portion of the crosslinking agent excluding the isocyanate group and the blocked isocyanate group is more preferable because it makes it easier to obtain flexibility even when the content of the organic electron transport compound is increased.

[0063] For example, when the molecular weight of the portion excluding the isocyanate group and blocked isocyanate group of the crosslinking agent is smaller, methylene diisocyanate has a molecular weight of 14, ethylene diisocyanate has a molecular weight of 28, propylene diisocyanate has a molecular weight of 42, and 1,4-diisocyanate butane has a molecular weight of 56.

[0064] The molecular weight of the portion of the crosslinking agent excluding the isocyanate group and the blocked isocyanate group is preferably 330 or less, and since methylene diisocyanate is unstable and difficult to handle, it is preferably 28 or more.

[0065] Since ethylene diisocyanate and propylene diisocyanate have low stability and poor workability, it is more preferable that the molecular weight of the portion of the crosslinking agent excluding the isocyanate group and the blocked isocyanate group be 56 or higher.

[0066] Examples of isocyanate compounds include, but are not limited to, the isocyanate compounds listed below. Furthermore, multiple isocyanate compounds may be used in combination.

[0067] Examples of isocyanate compounds include hexamethylene diisocyanate, pentamethylene diisocyanate, 1,4-diisocyanate butane, methylene diisocyanate, ethylene diisocyanate, propylene diisocyanate, 1,12-diisocyanate dodecane, methyl-2,6-diisocyanate hexanoate, 2,2,4-trimethylhexamethylene diisocyanate, norbornane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and 1,4-diisocyanate diisocyanate. Examples include cyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane, tolylene diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, phenylene diisocyanate, 1,3-bis(2-isocyanate-2-propyl)benzene, diphenylmethane diisocyanate, 2,2-bis(4-isocyanatephenyl)hexafluoropropane, 2,2-bis(3-methyl-4-isocyanatephenyl)hexafluoropropane, and 4,4'-diisocyanate-3,3'-dimethylbiphenyl.

[0068] In this disclosure, the crosslinking agent is preferably a compound represented by the following formula (3). When the isocyanate compound, which is the crosslinking agent in this disclosure, contains an aromatic ring, its strength increases due to the intermolecular forces of π-π interactions by the aromatic ring, making it more resistant to stress.

[0069] It is more preferable that the crosslinking agent is a compound represented by the following formula (3), because in the cured product of this disclosure, the strength is increased by intermolecular forces of π-π interactions, making it more resistant to stress. X-(R e ) l -(R g )-(R f ) k -X (3) (In formula (3), X is an isocyanate group or a blocked isocyanate group. g is a substituted or unsubstituted arylene group. l and k are independently 0 or 1. e , R f Each of these is independently a substituted or unsubstituted alkylene group. The number of carbon atoms in the arylene group is preferably 6 to 12, and the number of carbon atoms in the alkylene group is preferably 1 to 6.

[0070] Alternatively, in this disclosure, the crosslinking agent is preferably a compound represented by the following formula (4). When the isocyanate compound that is the crosslinking agent in this disclosure is a compound represented by the following formula (4), flexibility tends to be increased. X-(R h )-X (4) (In formula (4), X is an isocyanate group or a blocked isocyanate group. h (This refers to an alkylene group, either substituted or unsubstituted, with a main chain having 1 to 12 carbon atoms.)

[0071] In this disclosure, R h It is preferable that R is a substituted or unsubstituted alkylene group having 4 or 5 carbon atoms in the main chain. In the compound represented by formula (4), hWhen the alkylene group has 4 or 5 carbon atoms in the substituted or unsubstituted main chain, a good balance between flexibility and strength is achieved.

[0072] A ratio of parts by mass of the crosslinking agent to parts by mass of the organic electron-transporting compound in the composition is preferably 0.11 to 0.64, as this provides a good balance between flexibility and strength. In this disclosure, when the amount of the organic electron-transporting compound in the composition is 1 part by mass, it is preferable that the amount of the crosslinking agent is 0.11 to 0.64 parts by mass.

[0073] The electron transport layer composition may further contain an organic electron transport compound, a crosslinking agent, and a resin having polymerizable functional groups. In other words, it is preferable in this disclosure that the electron transport layer comprises a cured product of a composition containing an organic electron transport compound, a crosslinking agent, and a resin having polymerizable functional groups.

[0074] In this disclosure, when the total mass of solids in the composition is 100 parts by mass, the resin content in the composition is preferably 0.1 parts by mass or more and 18.0 parts by mass or less, and more preferably 5.0% by mass or less.

[0075] When the total mass of solids in the composition is 100 parts by mass, flexibility is easily improved when the resin content in the composition is 0.1 parts by mass or more. When the resin content in the composition is 18.0 parts by mass or less, flexibility and strength are good.

[0076] Examples of resins include polyacetal resin, polyvinyl acetal resin, polyolefin resin, polyester resin, polyether resin, and polyamide resin. Examples of functional groups in resins include hydroxyl groups, carboxyl groups, amino groups, and thiol groups.

[0077] Examples of commercially available resins having polymerizable functional groups include Bekkolite AL-4298-60, AS-019, Polylite OD-X-2420, OD-X-688 (manufactured by DIC Corporation), Esrec BX-1, BM-1, KS-5 (manufactured by Sekisui Chemical Co., Ltd.), Gosenex Z-100, Z-220, LW-100, LW-200 (manufactured by Mitsubishi Chemical Corporation), ARUFON UH-2000, UH-2041, UC-3000, UC-3080 (manufactured by Toagosei Co., Ltd.), and Hyros-X NS-2092, ZS-1417, X-1, X-210, BS-2060 (manufactured by Seikoh PMC Co., Ltd.).

[0078] The weight-average molecular weight of the resin having the polymerizable functional group is more preferably in the range of 5,000 to 400,000. More preferably, it is in the range of 5,000 to 300,000.

[0079] In addition to the polymers described above, the electron transport layer may also contain organic particles, inorganic particles, leveling agents, etc., to enhance film-forming properties and electrical characteristics. However, the content of these in the electron transport layer is preferably 20% by mass or less, and more preferably 10% by mass or less, relative to the total mass of the electron transport layer.

[0080] One method for forming an electron transport layer is to form a coating film of an electron transport layer coating solution containing the above-mentioned substances and then dry the coating film. When polymerizing these compositions during the drying of the coating film of the electron transport layer coating solution, the polymerization reaction (curing reaction) is accelerated by applying heat or light energy. Examples of solvents used in the electron transport layer coating solution include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon solvents.

[0081] Furthermore, from the viewpoint of electron injection properties, an electron injection layer may be provided on top of the electron transport layer or a second electron transport layer, and the material of the electron injection layer is not particularly limited, but bathocuproine and bathophenanthroline are preferred, for example.

[0082] The present disclosure will be described in detail below with reference to preferred embodiments. The present disclosure is not limited to the embodiments described below, and the scope of the present disclosure also includes modifications, improvements, etc., to the extent appropriate to the embodiments described below, based on the ordinary knowledge of those skilled in the art, without departing from the spirit of the present disclosure.

[0083] In this specification, the term "layer" refers not only to layers with clear boundaries or flat, thin films, but also to layers with gradually changing concentrations of constituent elements, and layers that can combine with other layers to form complex, interwoven structures.

[0084] Furthermore, elemental analysis of the layers can be performed, for example, by conducting TOF-SIMS / FE-TEM / EDS line analysis measurements of the cross-section of the photoelectric conversion element to confirm the elemental distribution of specific elements. Analysis of each layer may also be performed by peeling off the completed photoelectric conversion element, exposing the layer to be analyzed, and then measuring it.

[0085] Figure 1 is a schematic cross-sectional view showing the configuration of one embodiment of the photoelectric conversion element of the present disclosure. The photoelectric conversion element 1, as an example of the photoelectric conversion element of the present disclosure, has a first electrode 3, a hole transport layer 4, a photoelectric conversion layer 5, an electron transport layer 6, and a second electrode 7 on a substrate 2. One of the first electrode 3 and the second electrode 7 is the anode and the other is the cathode, and current can be extracted by connecting the first electrode 3 and the second electrode 7 with an external circuit.

[0086] The photoelectric conversion layer 5 is excited by light incident through the substrate 2, the first electrode 3, the hole transport layer 4, or the second electrode 7 and electron transport layer 6, generating electrons or holes. That is, the photoelectric conversion layer 5 generates an electric current between the first electrode 3 and the second electrode 7.

[0087] The hole transport layer 4 is a layer positioned between the photoelectric conversion layer 5 and the two electrodes (second electrode 7, first electrode 3), and may be omitted in some cases. Multiple layers of the hole transport layer 4, electron transport layer 6, and photoelectric conversion layer 5 may be stacked. Such a configuration can also be called a tandem structure. Each component is described below.

[0088] [Photoelectric conversion element] The photoelectric conversion element of the present disclosure comprises a first electrode, a second electrode, a photoelectric conversion layer containing a perovskite crystal disposed between the first electrode and the second electrode, and an electron transport layer disposed between the second electrode and the photoelectric conversion layer.

[0089] The photoelectric conversion element of this disclosure contains a cured product of a composition comprising an organic electron-transporting compound and a crosslinking agent in its electron transport layer. The organic electron-transporting compound can be cured by the addition of a crosslinking agent. If the electron transport layer of this disclosure contains additives as part of the composition, the composition may be considered to be the cured product. The chemical substances of this disclosure can be identified by nuclear magnetic resonance (NMR) spectrometers, mass spectrometers (e.g., MALDI-TOF-MS or GC-MS), etc.

[0090] Furthermore, to improve photoelectric conversion efficiency, a tandem type with stacked photoelectric conversion elements may be used. The type of photoelectric conversion element to be stacked is not limited to perovskite solar cells that use perovskite crystals as the photoelectric conversion layer, but also includes silicon solar cells, CIGS solar cells, etc.

[0091] Methods for forming the photoelectric conversion layer and charge transport layer of the photoelectric conversion element disclosed herein include coating methods and vapor deposition methods. Examples of coating methods include immersion coating, spin coating, spray coating, inkjet coating, meniscus coating, screen coating, roll coating, die coating, blade coating, curtain coating, and wire bar coating. The coating method involves preparing the coating solution for each layer, which will be described later, coating the layers in the desired order, and drying them. These film formation methods can be selected according to the requirements of each layer.

[0092] The following explains each layer. 〔substrate〕 As an example of a photoelectric conversion element in this disclosure, the photoelectric conversion element 1 may include a substrate 2, such as a transparent glass substrate like soda-lime glass or alkali-free glass, a ceramic substrate, or a transparent plastic substrate. When light is taken in from the second electrode 7 side, the substrate 2 can be made of an opaque material, and when light is taken in from the first electrode 3 side, the substrate 2 is made of a transparent material.

[0093] 〔electrode〕 The photoelectric conversion element disclosed herein has a first electrode and a second electrode. The materials of the first electrode 3 and the second electrode 7 are not particularly limited, and conventionally known materials can be used. Examples include metals such as gold, silver, titanium, and copper, sodium, sodium-potassium alloys, lithium, magnesium, carbon, carbon nanotubes, aluminum, magnesium-silver mixtures, magnesium-indium mixtures, aluminum-lithium alloys, Al / Al2O3 mixtures, Al / LiF mixtures, etc.

[0094] Examples of transparent electrode materials include conductive transparent materials such as CuI, ITO (indium tin oxide), SnO2, AZO (aluminum zinc oxide), IZO (indium zinc oxide), GZO (gallium zinc oxide), FTO (fluorine-doped tin oxide), and ATO (antimond-doped tin oxide), as well as conductive transparent polymers.

[0095] These materials may be used individually or in combination of two or more types. The first electrode 3 and the second electrode 7 may have at least one electrode on the light incidence side as a transparent electrode, while the other electrode may be a transparent electrode or also serve as a reflective layer made of a light-reflective material, or it may be a transparent electrode with a reflective layer on the side opposite to the light incidence side. When the second electrode 7 is on the light incidence side, the second electrode 7 may be a transparent electrode and the substrate 2 may be a reflective layer.

[0096] The electrodes may be patterned electrodes. Furthermore, the photoelectric conversion element of this disclosure may have a passivation layer formed on the first electrode 3. The passivation material is not particularly limited, but Al2O3 is preferred from the viewpoint of electrode surface treatment.

[0097] [Photoelectric conversion layer] The photoelectric conversion layer 5 has a perovskite crystal structure. The perovskite crystal used in this disclosure is preferably represented by the following general formula [1]. A o B p X q [1] In the above general formula [1], A is a cation, B is a cation, and X is an anion.

[0098] o, p, and q satisfy 0 ≤ o ≤ 10, 0 ≤ p ≤ 10, and 0 ≤ q ≤ 20, respectively, and A, B, and X may be composed of a single material or two or more materials may be used in combination. Additives may be added within the range in which the above general formula holds.

[0099] The above general formula generally forms a three-dimensional perovskite crystal. However, if the constituent cation A is large enough to fit within the three-dimensional perovskite crystal, it can form a two-dimensional perovskite crystal, a 2.5-dimensional perovskite crystal possessing properties of both two and three dimensions, a two-layer crystal of three-dimensional and two-dimensional perovskite structures, or a mixed three-dimensional / two-dimensional perovskite crystal, all of which function as a photoelectric conversion layer.

[0100] A two-layer crystal of 3D and 2D perovskite refers to a crystal in which 3D and 2D perovskite crystals are stacked as independent, separate layers, while a mixed 3D-2D perovskite refers to a crystal in which regions or domains of both 2D or 2.5D layered and 3D perovskite crystals are mixed.

[0101] Crystals of two-dimensional perovskites or 2.5-dimensional perovskite structures may form RP (Ruddlesden-Popper), DJ (Dion-Jacobson), or ACI (Alternating cations in the interlayer) type perovskite structures.

[0102] The cation A in the above general formula [1] is not particularly limited. The cation A may or may not have substituents, and specifically, examples include the following formulas (C1) to (C96).

[0103] [ka] [ka] [ka] [ka]

[0104] Furthermore, while the inorganic atoms are not particularly limited, lithium, cesium, sodium, potassium, and rubidium are preferred. These organic molecules or inorganic atoms may be used individually, or two or more may be used in combination.

[0105] In the general formula [1] above, B is a cation atom, and examples include lead, tin, bismuth, zinc, titanium, antimony, nickel, iron, cobalt, silver, copper, gallium, germanium, magnesium, calcium, indium, aluminum, manganese, chromium, molybdenum, and europium. Among these, lead, tin, bismuth, and silver are preferred from the viewpoint of the stability of the perovskite crystal structure. These atoms may be used individually or in combination of two or more.

[0106] In the above general formula [1], X is a halogen or chalcogen atom, such as chlorine, bromine, iodine, oxygen, sulfur, selenium, tellurium, or polonium. These halogen or chalcogen atoms may be used individually or in combination of two or more.

[0107] Among these, halogen atoms are preferred because the inclusion of halogen in the structure makes the crystals of the perovskite structure easily soluble in organic solvents, enabling application to low-cost printing methods and the like. Furthermore, iodine is more preferred because it narrows the energy band gap of the crystals of the perovskite structure.

[0108] Specifically, three-dimensional perovskites, two-dimensional perovskites, and mixed three-dimensional-two-dimensional perovskites include MAPbI3, FAPbCl3, FAPbI3, MAPbI x Br 3-x , MAPbI x Cl 3-x , Cs 0.05 (MA 0.17 FA 0.83 ) 0.95 Pb(I 0.83 Br 0.17 )3, {Cs x1 (FA x2 MA 1-x2 ) 1-x1} x3 Pb(I x4 Br 1-x4 ) x5 , Cs 0.05 FA 0.88 MA 0.07 PbI 2.56 Br 0.44 , (FAPbI3) 0.95 (MAPbBr3) 0.05 , (FAPbI3) 0.85 (MAPbBr3) 0.15 , CsPbI3, CsPbBr3, Cs x (MA) 1-x PbI3, Cs x (FA) 1-x PbI3, MA x (FA) 1-x PbI3, MA 0.17 FA 0.83 Pb(I 0.83 Br 0.17 )3, Cs 0.15 FA 0.85 PbI 2.55 Br 0.45 , Cs 0.05 FA 0.88 MA 0.07 PbI2.56 Br 0.44 , Cs 0.15 FA 0.85 PbI 2.55 Br 0.45 , (PEA)2(MA)2Pb3I 10 , (PTA)2(MA)4Pb5I 16 , (PEA)2(MA)4Pb5I 16 , (ThMA)2(MA)2Pb3I 10 , (3BBA)2(MA)2Pb3I 10 , (ThMA)2(FA)4Pb5I 16 , (4FPEA)2(FA 0.3 MA 0.7 )4Pb5I 16 , (PDMA)FA2Pb3I 10 , (3AMPY)(MA)3Pb4I 13 , (PDMA)MA5Pb6I 19 , (PDMA)MA3Pb4I 13 , (BA 0.9 PEA 0.1 )2MA4Pb5I 16 , (BA 0.9 PEA 0.1 )2MA3Pb4I 13 , (BA)2MA2Pb3I 10 , (BA)2MA3Pb4I 13 , (BA)2MA4Pb5I 16 , (BA)2MA3Pb4I 13 , CsSnBr3, CsSnI3, FA 0.75 MA 0.25 Sn 0.95 Ge 0.05 I3, FAMASnGeI3, FASnBr3, FASnI3, MA2Sn3I8, MASnBr3, MASnGeI3, and MASnI3 are preferred.

[0109] In the above specific examples, "MA" represents methylammonium, "FA" represents formamidinium, "PEA" represents phenethylammonium, "PTA" represents phenyltriethylammonium, "ThMA" represents 2-thiophenemethylammonium, "3BBA" represents 3-bromobenzylammonium, "3AMPY" represents 3-(aminomethyl)pyridine, "PDMA" represents 1,4-phenylenedimethaneammonium, "TTDMA" represents thieno[3,2-b]thiophene-2,5-diyldimethaneammonium, "4FPEA" represents 4-fluorophenethylammonium, and "BA" represents butylammonium.

[0110] Depending on the purpose, the A site, B site, and X site in the above general formula may be adjusted to be too little or too much, and the combinations of x1 to x5 may be changed according to the purpose. Examples of the combinations of x1 to x5 are shown in Table 7.

[0111] Particularly preferred ranges are 0.03 ≤ x1 ≤ 0.10, 0.80 ≤ x2 ≤ 0.96, 0.95 ≤ x3 ≤ 1.05, 0.80 ≤ x4 ≤ 0.96, and 2.95 ≤ x5 ≤ 3.05. MACl may also be included as the material for forming the perovskite crystal.

[0112] [Table 7]

[0113] The perovskite crystal described above preferably has a cubic crystal structure in which a metal atom B is located at the body center, organic molecules A are located at each vertex, and halogen atoms X are located at the face centers. Although the details are not clear, it is presumed that having such a structure allows the orientation of octahedra within the crystal lattice to be easily changed, thereby increasing the electron mobility in the perovskite crystal and improving the photoelectric conversion efficiency of the photoelectric conversion element.

[0114] The organic-inorganic perovskite compounds used in this disclosure are preferably crystalline semiconductors. A crystalline semiconductor is a semiconductor in which the X-ray scattering intensity distribution can be measured and a scattering peak can be detected. When the organic-inorganic perovskite compound is a crystalline semiconductor, the electron mobility in the organic-inorganic perovskite compound is increased, and the photoelectric conversion efficiency of the photoelectric conversion element is improved.

[0115] The thickness of the photoelectric conversion layer according to this disclosure is preferably 5 nm or more and 2000 nm or less. If the thickness of the photoelectric conversion layer is 5 nm or more, it can sufficiently absorb light, and if it is 2000 nm or less, it can transport the generated charge to each electrode. A more preferable lower limit for the thickness of the photoelectric conversion layer is 50 nm or more, an even more preferable lower limit is 100 nm, a more preferable upper limit for the thickness of the photoelectric conversion layer is 1200 nm, and an even more preferable upper limit is 1000 nm.

[0116] Furthermore, the photoelectric conversion element of this disclosure may have a passivation layer formed in or adjacent to the photoelectric conversion layer 5. The passivation material is not particularly limited and includes organic salts, inorganic salts, ionic liquids, and resins. The conductivity of the passivation material is not particularly limited and may be either insulating or conductive.

[0117] As the organic salt, a compound is preferred that consists of at least one cation selected from the group consisting of compounds represented by formulas (C1) to (C96) and at least one anion selected from the group consisting of compounds represented by the following formulas (A1) to (A29).

[0118] [ka]

[0119] The material of the inorganic salt is not particularly limited, but a compound composed of at least one cation selected from the group consisting of metal atoms and at least one anion selected from the group consisting of compounds represented by formulas (A1) to (A29) is preferred.

[0120] Examples of metal atoms include copper, silver, zinc, gallium, bismuth, sodium, potassium, lithium, vanadium, manganese, iron, cobalt, nickel, germanium, arsenic, selenium, lead, tin, iridium, platinum, osmium, cesium, barium, rubidium, molybdenum, and ruthenium.

[0121] The material of the ionic liquid is not particularly limited, but a compound composed of at least one cation selected from the group consisting of compounds represented by the following formulas (ILC1) to (ILC10) and at least one anion selected from the group consisting of compounds represented by the following formulas (ILA1) to (ILA17) is preferred.

[0122] [ka] (R 01 ~R 04 , and each independently represent a hydrogen atom, an optionally substituted alkyl group, and an optionally substituted aryl group.

[0123] The resin material is not particularly limited and may have substituents, including polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polystyrene (PS), polyimide (PI), fluororesin (PVDF), polyurethane (PU), silicone resin (PDMS), epoxy resin, nanocomposite resin, PEDOT:PSS, poly(9,9-dioctylfluorene-altenalyl) (PFN), P3HT, poly(fluorene-co Phenylene (PFP), polyvinylcarbazole (PVK), polythiophene (PTh), polyaniline (PANI), polybithiophene (PBTh), polydioxythiophene (PDT), polyoxyethylene (PEO), polyacrylic acid (PAA), polymethacrylic acid (PMAA), polyfumaric acid (PFA), polysuccinic acid (PSA), polyadipic acid (PAdA), polycaprolactam (PCL), polyisophthalic acid (PIPA), polyterephthalic acid (PT) A) Examples include polynaphthalenedicarboxylic acid (PNA), polyamide-imide (PAI), polysilsesquioxane (POSS), polyphenol resin (PF), polycarbonate (PC), poly(styrene-butadiene) (PSB), polysilyl ether (PSE), poly(ether-imide) (PEI), polyvinylpyrrolidone (PVP), polyacrylic acid ester (PAE), polydimethylaminoethyl methacrylate (PDMAEMA), polytrifluoroethylene (PTFE), polyoxymethylene (POM), polyesterimide (PEI), polyacrylonitrile (PAN), polyvinyl acetal (PVAH), polyolefin ether (PIE), polyacetal (PA), polysulfone (PSU), polyurea urethane (PUU), and polyolefin (PO), with polyvinyl acetal, polyolefin, polymethyl methacrylate, polyurethane, polyvinyl alcohol, and polyvinyl butyral being particularly preferred.

[0124] [Hole transport layer] In the photoelectric conversion element of this disclosure, a hole transport layer 4 may be arranged between the first electrode 3 and the photoelectric conversion layer 5, as shown in Figure 1. The thickness of the hole transport layer is preferably 0.1 nm or more and 1000 nm or less, more preferably 0.1 nm or more and 500 nm or less, and particularly preferably 0.1 nm or more and 200 nm or less.

[0125] The hole transport layer can be formed by preparing a coating solution for the hole transport layer containing the materials and solvents described below, forming this coating film on an ITO electrode, and drying it. Examples of solvents that can be used in the coating solution include amide solvents, aproton solvents, alcohol solvents, ketone solvents, ether solvents, ester solvents, and aromatic hydrocarbon solvents.

[0126] Among these solvents, amide solvents, aproton solvents, alcohol solvents, or aromatic hydrocarbon solvents are preferred. Furthermore, in this disclosure, from the viewpoint of the compatibility of the hole transport layer 4 film, a second charge transport layer may be further provided between the hole transport layer 4 and the first electrode 3.

[0127] The material of the hole transport layer 4 or the second charge transport layer is not particularly limited, and examples include spirofluorene compounds, triphenylamine compounds, chrysene compounds, pyrene compounds, phthalocyanine compounds, carbazole compounds, fluorene compounds, phenylcyclohexane compounds, benzidine compounds, phenoxazine compounds, phenylenediamine compounds, thiocyanate compounds, phenothiazine compounds, triazaalkene compounds, cyclooctatetraene compounds, squalate compounds, etc.

[0128] In particular, the material of the hole transport layer 4 or the second charge transport layer preferably has an aromatic ring from the viewpoint of compatibility at the film interface, and Spiro-OMeTAD, PTAA, phenothiazine compounds, carbazole compounds, triphenylamine compounds, triazaalkene compounds, cyclooctatetraene compounds, and squalate compounds are preferred.

[0129] Furthermore, a passivation material may be provided in or on the hole transport layer 4. The passivation material is not particularly limited and includes organic salts, inorganic salts, ionic liquids, and resins. The conductivity of the passivation material is not particularly limited and may be either insulating or conductive.

[0130] As the organic salt, a compound composed of at least one cation selected from the group consisting of compounds represented by formulas (C1) to (C96) and at least one anion selected from the group consisting of compounds represented by formulas (A1) to (A29) is preferred.

[0131] As inorganic salts, compounds composed of at least one cation selected from the group consisting of metal atoms and at least one anion selected from the group consisting of compounds represented by formulas (A1) to (A29) are preferred.

[0132] Examples of metal atoms include copper, silver, zinc, gallium, bismuth, sodium, potassium, lithium, vanadium, manganese, iron, cobalt, nickel, germanium, arsenic, selenium, lead, tin, iridium, platinum, osmium, cesium, barium, rubidium, molybdenum, and ruthenium.

[0133] The material of the ionic liquid is not particularly limited, but a compound composed of at least one cation selected from the group consisting of compounds represented by formulas (ILC1) to (ILC10) and at least one anion selected from the group consisting of compounds represented by formulas (ILA1) to (ILA17) is preferred. 01 ~R 04 , independently represent a hydrogen atom, an optionally substituted alkyl group, and an optionally substituted aryl group, respectively.

[0134] The resin material is not particularly limited and may have substituents, including polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polystyrene (PS), polyimide (PI), fluororesin (PVDF), polyurethane (PU), silicone resin (PDMS), epoxy resin, nanocomposite resin, PEDOT:PSS, poly(9,9-dioctylfluorene-altenalyl) (PFN), P3HT, poly(fluorene-co Phenylene (PFP), polyvinylcarbazole (PVK), polythiophene (PTh), polyaniline (PANI), polybithiophene (PBTh), polydioxythiophene (PDT), polyoxyethylene (PEO), polyacrylic acid (PAA), polymethacrylic acid (PMAA), polyfumaric acid (PFA), polysuccinic acid (PSA), polyadipic acid (PAdA), polycaprolactam (PCL), polyisophthalic acid (PIPA), polyterephthalic acid (PT) A) Examples include polynaphthalenedicarboxylic acid (PNA), polyamide-imide (PAI), polysilsesquioxane (POSS), polyphenol resin (PF), polycarbonate (PC), poly(styrene-butadiene) (PSB), polysilyl ether (PSE), poly(ether-imide) (PEI), polyvinylpyrrolidone (PVP), polyacrylic acid ester (PAE), polydimethylaminoethyl methacrylate (PDMAEMA), polytrifluoroethylene (PTFE), polyoxymethylene (POM), polyesterimide (PEI), polyacrylonitrile (PAN), polyvinyl acetal (PVAH), polyolefin ether (PIE), polyacetal (PA), polysulfone (PSU), polyurea urethane (PUU), and polyolefin (PO), with polyvinyl acetal, polyolefin, polymethyl methacrylate, polyurethane, polyvinyl alcohol, and polyvinyl butyral being particularly preferred.

[0135] [Electron transport layer] In this disclosure, the electron transport layer 6 contains a cured product of a composition containing an organic electron transport compound having polymerizable functional groups that can react with isocyanate groups and a crosslinking agent, wherein the crosslinking agent is a bifunctional isocyanate compound, the molecular weight of the portion of the crosslinking agent excluding the isocyanate groups and blocked isocyanate groups is 14 or more and 330 or less, the total number of isocyanate groups and blocked isocyanate groups is 2 per molecule, and it is disposed between the second electrode 7 and the photoelectric conversion layer 5. In this disclosure, it is preferable that the organic electron transport compound has 2 polymerizable functional groups.

[0136] The preferred lower limit for the thickness of the electron transport layer 6 is 1 nm, and the preferred upper limit is 2000 nm. If the thickness of the electron transport layer 6 is 1 nm or more, holes can be sufficiently blocked, and if it is 2000 nm or less, it will not be a resistance during electron transport, and the photoelectric conversion efficiency will be high. A more preferred lower limit for the thickness is 1 nm, a more preferred upper limit is 1000 nm, an even more preferred lower limit is 1 nm, and an even more preferred upper limit is 500 nm.

[0137] Furthermore, in this disclosure, a second electron transport layer may be provided between the electron transport layer 6 and the second electrode 7, from the viewpoint of the compatibility of the electron transport layer 6 film. The material of the second electron transport layer is not particularly limited and includes, for example, N-type conductive polymers, N-type low molecular weight organic semiconductors, N-type metal oxides, N-type metal sulfides, alkali metal halides, alkali metals, surfactants, and the like.

[0138] Examples of materials for the second electron transport layer include, specifically, cyano group-containing polyphenylene vinylene, boron-containing polymers, vasocuproin, vasophenanthroline, hydroxyquinolinatoaluminum, oxadiazole compounds, benzimidazole compounds, naphthalenetetracarboxylic acid compounds, fullerene compounds, perylene derivatives, phosphine oxide compounds, phosphine sulfide compounds, fluoro group-containing phthalocyanines, titanium dioxide, zinc oxide, indium oxide, tin oxide, gallium oxide, tin sulfide, indium sulfide, zinc sulfide, etc. In particular, tin oxide may be obtained by reacting tin(2) chloride, tin(4) chloride, tin(2) chloride dihydrate, or tin(4) chloride pentahydrate.

[0139] [Modularization Process] When manufacturing solar cells, cutting processes may be performed between each stage of the manufacturing process to form circuits. Examples of cutting processes include mechanical patterning and laser patterning.

[0140] Furthermore, the element with electrodes formed may be sealed. Examples of sealing methods include sealing with a resin or sealing with a film containing a resin. Examples of materials used for sealing include silazane, silicone rubber, resins having a siloxane skeleton, resins containing fluorine, and glass.

[0141] Furthermore, from the viewpoint of suppressing adhesion between elements that occurs when winding in a roll-to-roll manner, the surface of the sealed elements may be given a hairline finish.

[0142] <Application Examples> Examples of applications of this disclosure include photoelectric converters, mobile devices, and building materials. [Photoelectric converter] The photoelectric conversion device disclosed herein comprises a photoelectric conversion element disclosed herein. A photoelectric conversion device can be configured by using multiple photoelectric conversion elements disclosed herein. When multiple photoelectric conversion elements are connected together, such a photoelectric conversion device may also be called a photoelectric conversion cell or a photoelectric conversion module.

[0143] The photoelectric conversion element may be stacked with photoelectric conversion elements having different absorption wavelengths to increase the output voltage. Furthermore, the photoelectric conversion device includes the photoelectric conversion element of this disclosure and an inverter. The inverter may be a converter that converts direct current to alternating current.

[0144] The photoelectric conversion device may have a power storage unit connected to the photoelectric conversion element. The power storage unit is not limited to any device that can store electricity. Examples include secondary batteries using lithium ions, all-solid-state batteries, and electric double-layer capacitors. To provide functions such as maintaining or increasing the amount of incident light, a surface that is resistant to water and dirt, or a function to collect or guide light may be added.

[0145] [Mobile] The mobile body of the present disclosure has a photoelectric conversion element of the present disclosure. Figure 2 is a schematic perspective view showing one embodiment of a mobile body equipped with the photoelectric conversion element of the present disclosure. The mobile body 30 has a photoelectric conversion element 31 of the present disclosure and a body 32 equipped with the photoelectric conversion element 31. The photoelectric conversion element 31 is positioned in a location on the body 32 that can receive ambient light. The mobile body of the present disclosure can be applied, for example, to the mobile body 30 shown in Figure 2, and the photoelectric conversion element of the present disclosure can be applied to the photoelectric conversion element 31 in Figure 2.

[0146] If the mobile body 30 is an automobile, it may be placed on the roof. The electrical energy obtained by the photoelectric conversion element 31 may be used to power the mobile body 30 or other electrical equipment. The electrical energy generated from the power of the mobile body 30 may be used to power the photoelectric conversion element 31. If the mobile body 30 is an automobile, the frictional energy generated by the brakes may be converted into electrical energy and used to control the photoelectric conversion element 31.

[0147] The mobile body 30 may be, for example, an automobile, a motorcycle, a railway vehicle, a ship, a satellite, an airplane, or a drone. The structure of the mobile body 32 is not particularly limited, but it is preferably made of a high-strength material.

[0148] [Building materials] The building material of this disclosure has a photoelectric conversion element of this disclosure. Figure 3 is a schematic perspective view showing one embodiment of the building material equipped with the photoelectric conversion element of this disclosure. The building material of this disclosure can be applied, for example, to the building material 40 shown in Figure 3, and the photoelectric conversion element of this disclosure can be applied to the photoelectric conversion element 41 in Figure 3. The building material 40 may be the roof of a building. The building material 40 has a photoelectric conversion element 41, a protective member 42 for protecting the photoelectric conversion element 41, a heat dissipation member 43, and exterior parts 44a, 44b.

[0149] The building material 40 may have a heat dissipation member 43 with a higher thermal conductivity than the photoelectric conversion element 41. When used on a roof or the like, the temperature of the photoelectric conversion element 41 may rise due to sunlight, which may reduce the photoelectric conversion efficiency. The reduction in photoelectric conversion efficiency can be reduced by using the heat dissipation member 43. Examples of the heat dissipation member 43 include metal, alloy, liquid metal, and liquid resin.

[0150] Furthermore, the building material 40 may have exteriors 44a and 44b. Exteriors 44a and 44b may have different colors or the same color. Exteriors 44a and 44b may be made of the same material or different materials. Paints and transparent substrates may be used as exteriors. Materials with low light absorption and high heat shielding properties are preferred.

[0151] In addition to the above examples of applications, the following are some other examples of applications: Portable devices include calculators, sensors, and small solar panels. Wearable devices include eyeglasses, smartwatches, and portable medical devices.

[0152] Examples of sheet structures supported by multiple frames include tents, greenhouses, and truck beds. Examples of structures used in a fixed position include road panels, floating panels, building materials that utilize the flexibility of the substrate, wall-type building materials, glass-type building materials, and mega solar panels. [Examples]

[0153] The present disclosure will be described in more detail below using examples and comparative examples. The present disclosure is not limited in any way by the following examples unless it exceeds the gist of the disclosure. In the following examples, "parts" refers to a mass basis unless otherwise specified.

[0154] (Example 1) [Hole transport layer formation] A square glass substrate with ITO, measuring 25 mm on each side, was cleaned. A 0.01 mM solution of 3PATAT-3C (manufactured by Tokyo Chemical Industry Co., Ltd.) was prepared in 100 mL of N,N-dimethylformamide (DMF), and this solution was applied to the substrate by spin coating. The substrate was then heated at 110°C for 10 minutes to form a thin film-like hole transport layer.

[0155] [Formation of the photoelectric conversion layer] 0.044 g of lead bromide, 0.392 g of formamidium iodide, 1.144 g of lead iodide, 0.0134 g of methylammonium bromide, and 0.0176 g of methylammonium chloride were dissolved in 1384 μL of DMF and 252.4 μL of dimethyl sulfoxide (DMSO), and the mixture was stirred for 2 hours (Solution 1).

[0156] Furthermore, 0.036 g of cesium iodide was dissolved in 96.6 μL of DMSO and stirred for 2 hours (Solution 2). Then, the dissolved cesium iodide solution (Solution 2) was added to Solution 1 to prepare the photoelectric conversion layer coating solution. This coating solution was spin-coated onto the hole transport layer using a poor solvent method and heated at 100°C for 10 minutes to obtain {Cs 0.05 (FA 0.86 MA 0.14 ) 0.95} 0.98 Pb(I 0.95 Br 0.05 ) 2.98 A photoelectric conversion layer with a thickness of 450 nm was obtained.

[0157] [Formation of the passivation layer] 2-phenylethylamine hydroiodide was prepared in 2-propanol (IPA) at a concentration of 1 mg / mL. This solution was applied by spin coating to obtain a passivation layer.

[0158] [Formation of Electron Transport Layer] Through the following operations, a coating solution for electron transport layer was prepared, and spin-coated onto the photoelectric conversion layer at 2800 rpm. Thereafter, the resultant was heated at 140°C for 30 minutes to form an electron transport layer with a thickness of about 30 nm. The coating solution for electron transport layer was prepared in consideration of leaving block groups and the like, such that the content of the electron transporting compound was 80 mass% relative to the total mass of the electron transport layer after film formation.

[0159] As the electron transporting compound, 8.00 parts of the compound represented by formula (E1-13), which is an exemplary compound in Table 9, as resins, 0.10 parts of a polyolefin resin (trade name: UC-3920, manufactured by Toagosei Co., Ltd.) and 0.10 parts of a polyvinyl acetal resin (trade name: KS-5Z, manufactured by Sekisui Chemical Co., Ltd.), and as a crosslinking agent, 1.81 parts of hexamethylene diisocyanate which is a compound represented by the following formula (D1), were dissolved in a mixed solvent of 480 parts of THF / 240 parts of orthoxylene. Thereafter, pressure filtration was performed using a Teflon (registered trademark) filter manufactured by ADVANTEC (product name: PF020). [Chemical Formula]

[0160] [Formation of Electron Injection Layer] Bathocuproine (BCP) was prepared in IPA at a concentration of 0.5 mg / mL. The solution was applied by spin coating to obtain an electron injection layer.

[0161] [Formation of Second Electrode] On the electron injection layer, 10 Ag electrodes each having an area of 0.09 cm 2 were formed, to obtain a photoelectric conversion element. The characteristic values measured by electron microscope observation of the photoelectric conversion element are shown in Table 9.

[0162] [Evaluation] [Initial Characteristics] A power source (manufactured by KEITHLEY, Model 236) was connected between the electrodes of the fabricated photoelectric conversion element, at an intensity of 100 mW / cm 2Using a solar simulator (manufactured by Yamashita Densou Co., Ltd.), a constant amount of light was irradiated onto the photoelectric element, and the generated current and voltage were measured to determine the photoelectric conversion efficiency (PCE), open-circuit voltage (Voc), short-circuit current density (Jsc), and fill factor (FF). Measurements were also taken at 10 electrodes for each photoelectric element, and the average value was used as the representative value for that element. This value was used as the initial value.

[0163] [Repeated heat and light resistance test] The photoelectric conversion element was held at 25°C for 1 hour in a nitrogen atmosphere. Then, under 1 sun irradiation, the temperature was increased at 10°C per minute until it reached 60°C, and it was held at this temperature for 3 hours. After that, the light irradiation was turned off, and the temperature was cooled to 25°C at the same rate, and held at this temperature for 3 hours. This cycle was repeated 100 times. After the test, the fast-flush (FF) was measured in the same manner as the initial characteristics, and the ratio of the FF after durability to the initial FF was calculated. The evaluation results are shown in Table 9.

[0164] (Examples 2-42) Except for changing the type and content of the electron-transporting compound mixed in the coating solution for the electron transport layer, the type and content of the crosslinking agent, and the type and content of the resin as shown in Tables 8 and 9, a photoelectric conversion element was fabricated in the same manner as in Example 1 and evaluated in the same way. The results are shown in Table 9.

[0165] [Table 8]

[0166] [Table 9]

[0167] (Comparative Example 1) Except for changing the type and content of the electron transport compound mixed in the coating solution for the electron transport layer, the type and content of the crosslinking agent, and the type and content of the resin as shown in Table 9, a photoelectric conversion element was fabricated in the same manner as in Example 1 and evaluated in the same way. The results are shown in Table 9. The crosslinking agent is a compound represented by the following formula (D12), which is triphenylmethane triisocyanate. [ka]

[0168] (Comparative Example 2) Except for changing the type and content of the electron transport compound mixed in the coating solution for the electron transport layer, the type and content of the crosslinking agent, and the type and content of the resin as shown in Table 9, a photoelectric conversion element is fabricated and evaluated in the same manner as in Example 1.

[0169] The results are shown in Table 9. The crosslinking agent is a blocked isocyanate compound (trade name: SBN-70D, manufactured by Asahi Kasei Corporation, solid content 70% by mass) (a trifunctional blocked isocyanate compound in which hexamethylene diisocyanate is trimerized to form a triazine ring at the center).

[0170] (Comparative Example 3) Except for changing the type and content of the electron transport compound mixed in the coating solution for the electron transport layer, the type and content of the crosslinking agent, and the type and content of the resin as shown in Tables 8 and 9, a photoelectric conversion element was fabricated in the same manner as in Example 1 and evaluated in the same way. The results are shown in Table 9. The crosslinking agent is a compound represented by the following formula (D13), which is dicyclopentadiene diepoxide. [ka]

[0171] (Comparative Example 4) A photoelectric conversion element is produced in the same manner as in Example 1, and the same evaluation is performed, except that the type and content of the electron-transporting compound, the type and content of the crosslinking agent, and the type and content of the resin to be mixed into the coating liquid for an electron transport layer are changed as shown in Table 9. The results are shown in Table 9. The crosslinking agent is poly(propylene glycol), toluene 2,4-diisocyanate-terminated (number average molecular weight (Mn) 2300), represented by the following formula (D14).

Chemical Formula

[0172] (Comparative Example 5) A photoelectric conversion element is produced in the same manner as in Example 1, and the same evaluation is performed, except that the type and content of the electron-transporting compound, the type and content of the crosslinking agent, and the type and content of the resin to be mixed into the coating liquid for an electron transport layer are changed as shown in Table 9. The results are shown in Table 9.

[0173] (Comparative Example 6) A photoelectric conversion element is produced in the same manner as in Example 1, and the same evaluation is performed, except that the type and content of the electron-transporting compound, the type and content of the crosslinking agent, and the type and content of the resin to be mixed into the coating liquid for an electron transport layer are changed as shown in Table 9. The results are shown in Table 9. The electron-transporting compound is a compound represented by the following formula (PD29).

Chemical Formula

[0174] (Comparative Example 7) A photoelectric conversion element is produced in the same manner as in Example 1, and the same evaluation is performed, except that the type and content of the electron-transporting compound, the type and content of the crosslinking agent, and the type and content of the resin to be mixed into the coating liquid for an electron transport layer are changed as shown in Table 9. The results are shown in Table 9. The crosslinking agent is a compound represented by the following formula (D15), which is 1,6-bis(trichlorosilyl)hexane. The electron-transporting compound is a compound represented by the following formula (E5).

Chemical Formula

[0175] (Comparative Example 8) Except for changing the type and content of the electron-transporting compound mixed in the coating solution for the electron transport layer, the type and content of the crosslinking agent, and the type and content of the resin as shown in Table 9, a photoelectric conversion element was fabricated in the same manner as in Example 1 and evaluated in the same way. The results are shown in Table 9.

[0176] This embodiment includes the following configuration. (Composition 1) A photoelectric conversion element comprising a first electrode, a second electrode, a photoelectric conversion layer containing a perovskite crystal disposed between the first electrode and the second electrode, and an electron transport layer disposed between the second electrode and the photoelectric conversion layer, The electron transport layer contains a cured product of a composition comprising an organic electron transport compound having a polymerizable functional group that can react with an isocyanate group, and a crosslinking agent. The crosslinking agent is a bifunctional isocyanate compound, A photoelectric conversion element characterized in that the molecular weight of the portion of the crosslinking agent excluding the isocyanate group and the blocked isocyanate group is between 14 and 330. (Configuration 2) The photoelectric conversion element according to configuration 1, wherein the molecular weight of the portion of the crosslinking agent excluding the isocyanate group and the blocked isocyanate group is 14 or more and 160 or less. (Composition 3) The photoelectric conversion element according to configuration 1 or 2, wherein the crosslinking agent is a compound represented by the following formula (3). X-(R e ) l -(R g )-(R f ) k -X (3) (In formula (3), X is an isocyanate group or a blocked isocyanate group. gis a substituted or unsubstituted arylene group. l and k are independently 0 or 1. e , R f These are, independently, substituted or unsubstituted alkylene groups. (Composition 4) A photoelectric conversion element according to any one of configurations 1 to 3, wherein the crosslinking agent is a compound represented by the following formula (4). X-(R h )-X (4) (In formula (4), X is an isocyanate group or a blocked isocyanate group. h (This refers to an alkylene group, either substituted or unsubstituted, with a main chain having 1 to 12 carbon atoms.) (Composition 5) The aforementioned R h The photoelectric conversion element according to configuration 4, wherein the alkylene group is substituted or unsubstituted, and has 4 or 5 carbon atoms in the main chain. (Composition 6) A photoelectric conversion element according to any one of configurations 1 to 5, wherein, when the total mass of solids in the composition is 100 parts by mass, the content of the organic electron transport compound in the composition is 50 parts by mass or more and 90 parts by mass or less. (Composition 7) A photoelectric conversion element according to any one of configurations 1 to 6, wherein when the amount of the organic electron transporting compound in the composition is 1 part by mass, the amount of the crosslinking agent is 0.11 parts by mass or more and 0.64 parts by mass or less. (Composition 8) The photoelectric conversion element according to any one of configurations 1 to 7, wherein the organic electron transport compound contains at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a thiol group, and a heteroatom. (Composition 9) The photoelectric conversion element according to any one of configurations 1 to 8, wherein the organic electron transport compound has two polymerizable functional groups. (Composition 10) The photoelectric conversion element according to any one of configurations 1 to 9, wherein the organic electron transporting compound is at least one compound selected from the group consisting of the compound represented by the following formula (E1), the compound represented by the following formula (E2), the compound represented by the following formula (E3), and the compound represented by the following formula (E4). [ka] [ka] [ka] [ka] (In formulas (E1) to (E4), R 11 ~R 20 , R 21 ~R 26 , R 31 ~R 34 , and R 41 ~R 48 Each independently represents a functional group selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 20 substituted or unsubstituted carbon atoms, an aryl group having 6 to 28 substituted or unsubstituted carbon atoms, an arylalkyl group having 7 to 28 substituted or unsubstituted carbon atoms, a hydroxyl group, a carboxyl group, an amino group, a thiol group, a halogen atom, a cyano group, and a nitro group. In this case, R 11 ~R 20 , R 21 ~R 26 , R 31 ~R 34 , and R 41 ~R 48 However, adjacent groups may be linked together to form a ring. 11 ~R 20 One or more of these are groups containing a functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a thiol group, R 21 ~R 26One or more of these are groups containing a functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a thiol group, R 31 ~R 34 One or more of these are groups containing a functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a thiol group, R 41 ~R 48 One or more of these groups contain a functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a thiol group. (Composition 11) In the above equations (E1) to (E4), R 11 ~R 20 , R 21 ~R 26 , R 31 ~R 34 , and R 41 ~R 48 Each of these is an independent group represented by formula (1) below, the photoelectric conversion element described in configuration 10. -(R a ) m -(R b ) n -R c (1) (In equation (1), m and n are independently either 0 or 1.) In formula (1), R a R in formula (1) represents an alkylene group having 1 to 10 substituted or unsubstituted carbon atoms, or an arylene group having 6 to 14 substituted or unsubstituted carbon atoms. c Or R in formula (2) below d They may be connected to each other to form a ring. In formula (1), R b represents an oxygen atom, a sulfur atom, or a group represented by the following formula (2). [ka] (In formula (2), R d R represents a hydrogen atom, or an alkyl group having 1 to 4 substituted or unsubstituted carbon atoms. In this case, R in formula (1) a or R in equation (1) cThey may be connected to each other to form a ring. In formula (1), R c R represents a hydrogen atom, an alkyl group having 1 to 10 substituted or unsubstituted carbon atoms, an aryl group having 6 to 14 substituted or unsubstituted carbon atoms, or an arylalkyl group having 7 to 18 substituted or unsubstituted carbon atoms. In this case, R in formula (1) a or R in equation (2) d They may be connected to each other to form a ring. The substituents that the alkylene group and the alkyl group may have are a hydroxyl group, a carboxyl group, an amino group, a thiol group, an alkoxy group having 1 to 3 carbon atoms, and an alkoxycarbonyl group having 2 to 4 carbon atoms. The substituents that the arylene group, the aryl group, and the arylalkyl group may have are alkyl groups having 1 to 3 carbon atoms, hydroxyl groups, hydroxyalkyl groups having 1 to 3 carbon atoms, carboxyl groups, amino groups, thiol groups, alkoxy groups having 1 to 3 carbon atoms, alkoxycarbonyl groups having 2 to 4 carbon atoms, halogen atoms, cyano groups, and nitro groups. However, R 11 ~R 20 One or more of these are groups containing a functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a thiol group, R 21 ~R 26 One or more of these are groups containing a functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a thiol group, R 31 ~R 34 One or more of these are groups containing a functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a thiol group, R 41 ~R 48 One or more of these groups contain a functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a thiol group. (Composition 12) A photoelectric conversion element according to any one of configurations 1 to 11, wherein the electron transport layer includes a cured product of a composition containing the organic electron transport compound, the crosslinking agent, and a resin having polymerizable functional groups. (Composition 13) The photoelectric conversion element according to configuration 12, wherein, when the total mass of solids in the composition is 100 parts by mass, the content ratio of the resin in the composition is 0.1 parts by mass or more and 18.0 parts by mass or less. (Composition 14) A photoelectric conversion device comprising a photoelectric conversion element described in any one of configurations 1 to 13. [Explanation of symbols]

[0177] 1. Photoelectric conversion element 2 circuit boards 3 First electrode 4. Hole transport layer 5 Photoelectric conversion layer 6 Electron transport layer 7 Second electrode 30 Mobile Units 31, 41 Photoelectric conversion element 32 aircraft 40 Building materials 42 Protective member 43 Heat dissipation components 44a, 44b Exterior

Claims

1. A photoelectric conversion element comprising a first electrode, a second electrode, a photoelectric conversion layer containing a perovskite crystal disposed between the first electrode and the second electrode, and an electron transport layer disposed between the second electrode and the photoelectric conversion layer, The electron transport layer contains a cured product of a composition comprising an organic electron transport compound having a polymerizable functional group that can react with an isocyanate group, and a crosslinking agent. The crosslinking agent is a bifunctional isocyanate compound, A photoelectric conversion element characterized in that the molecular weight of the portion of the crosslinking agent excluding the isocyanate group and the blocked isocyanate group is 14 or more and 330 or less.

2. The photoelectric conversion element according to claim 1, wherein the molecular weight of the portion of the crosslinking agent excluding the isocyanate group and the blocked isocyanate group is 14 or more and 160 or less.

3. The photoelectric conversion element according to claim 1, wherein the crosslinking agent is a compound represented by the following formula (3). X-(R ｅ ) ｌ -(R ｇ )-(R ｆ ) ｋ -X (3) (In formula (3), X is an isocyanate group or a blocked isocyanate group. ｇ is a substituted or unsubstituted arylene group. l and k are independently 0 or 1. ｅ , R ｆ These are, independently, substituted or unsubstituted alkylene groups.

4. The photoelectric conversion element according to claim 1, wherein the crosslinking agent is a compound represented by the following formula (4). X-(R ｈ )-X (4) (In formula (4), X is an isocyanate group or a blocked isocyanate group. ｈ (This refers to an alkylene group, which is substituted or unsubstituted, with a main chain having 1 to 12 carbon atoms.)

5. The aforementioned R ｈ The photoelectric conversion element according to claim 4, wherein is a substituted or unsubstituted alkylene group having 4 or 5 carbon atoms in the main chain.

6. The photoelectric conversion element according to claim 1, wherein, when the total mass of solids in the composition is 100 parts by mass, the content of the organic electron transporting compound in the composition is 50 parts by mass or more and 90 parts by mass or less.

7. The photoelectric conversion element according to claim 1, wherein when the amount of the organic electron transporting compound in the composition is 1 part by mass, the amount of the crosslinking agent is 0.11 parts by mass or more and 0.64 parts by mass or less.

8. The photoelectric conversion element according to claim 1, wherein the organic electron transport compound contains at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a thiol group, and a heteroatom.

9. The photoelectric conversion element according to claim 1, wherein the organic electron transport compound has two polymerizable functional groups.

10. The photoelectric conversion element according to claim 1, wherein the organic electron transporting compound is at least one compound selected from the group consisting of the compound represented by the following formula (E1), the compound represented by the following formula (E2), the compound represented by the following formula (E3), and the compound represented by the following formula (E4). 【Chemistry 1】 【Chemistry 2】 【Transformation 3】 【Chemistry 4】 (In formulas (E1) to (E4), R １１ ~R ２０ , R ２１ ~R ２６ , R ３１ ~R ３４ , and R ４１ ~R ４８ Each independently represents a functional group selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 20 substituted or unsubstituted carbon atoms, an aryl group having 6 to 28 substituted or unsubstituted carbon atoms, an arylalkyl group having 7 to 28 substituted or unsubstituted carbon atoms, a hydroxyl group, a carboxyl group, an amino group, a thiol group, a halogen atom, a cyano group, and a nitro group. In this case, R １１ ~R ２０ , R ２１ ~R ２６ , R ３１ ~R ３４ , and R ４１ ~R ４８ However, adjacent groups may be linked together to form a ring. １１ ~R ２０ One or more of these are groups containing a functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a thiol group, R ２１ ~R ２６ One or more of these are groups containing a functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a thiol group, R ３１ ~R ３４ One or more of these are groups containing a functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a thiol group, R ４１ ~R ４８ One or more of these groups contain a functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a thiol group.

11. In the above formulas (E1) to (E4), R １１ ~R ２０ , R ２１ ~R ２６ , R ３１ ~R ３４ , and R ４１ ~R ４８ The photoelectric conversion element according to claim 10, wherein each of the elements is independently a group represented by the following formula (1). -(R ａ ) ｍ -(R ｂ ) ｎ -R ｃ (1) (In equation (1), m and n are independently either 0 or 1.) In formula (1), R ａ R in formula (1) represents an alkylene group having 1 to 10 substituted or unsubstituted carbon atoms, or an arylene group having 6 to 14 substituted or unsubstituted carbon atoms. ｃ Or R in formula (2) below ｄ They may be connected to each other to form a ring. In formula (1), R ｂ represents an oxygen atom, a sulfur atom, or a group represented by the following formula (2). 【Transformation 5】 (In formula (2), R ｄ R represents a hydrogen atom, or an alkyl group having 1 to 4 substituted or unsubstituted carbon atoms. In this case, R in formula (1) ａ or R in formula (1) ｃ They may be connected to each other to form a ring. In formula (1), R ｃ R represents a hydrogen atom, an alkyl group having 1 to 10 substituted or unsubstituted carbon atoms, an aryl group having 6 to 14 substituted or unsubstituted carbon atoms, or an arylalkyl group having 7 to 18 substituted or unsubstituted carbon atoms. In this case, R in formula (1) ａ or R in formula (2) ｄ They may be connected to each other to form a ring. The substituents that the alkylene group and the alkyl group may have are a hydroxyl group, a carboxyl group, an amino group, a thiol group, an alkoxy group having 1 to 3 carbon atoms, and an alkoxycarbonyl group having 2 to 4 carbon atoms. The substituents that the arylene group, the aryl group, and the arylalkyl group may have are alkyl groups having 1 to 3 carbon atoms, hydroxyl groups, hydroxyalkyl groups having 1 to 3 carbon atoms, carboxyl groups, amino groups, thiol groups, alkoxy groups having 1 to 3 carbon atoms, alkoxycarbonyl groups having 2 to 4 carbon atoms, halogen atoms, cyano groups, and nitro groups. However, R １１ ~R ２０ One or more of these are groups containing a functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a thiol group, R ２１ ~R ２６ One or more of these are groups containing a functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a thiol group, R ３１ ~R ３４ One or more of these are groups containing a functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a thiol group, R ４１ ~R ４８ One or more of these groups contain a functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a thiol group.

12. The photoelectric element according to claim 1, wherein the electron transport layer comprises a cured product of a composition containing the organic electron transport compound, the crosslinking agent, and a resin having polymerizable functional groups.

13. The photoelectric conversion element according to claim 12, wherein when the total mass of solids in the composition is 100 parts by mass, the content ratio of the resin in the composition is 0.1 parts by mass or more and 18.0 parts by mass or less.

14. A photoelectric conversion device comprising a photoelectric conversion element according to any one of claims 1 to 13.

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