Photoelectric conversion element

Abstract

To provide a photoelectric conversion element with improved durability. [Solution] 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, wherein the electron transport layer contains a cured product of a composition containing an electron transport compound and a crosslinking agent, and the ASA of the electron transport compound, calculated by the following formulas (1) and (2), is 240 Å. 2 The above describes a photoelectric conversion element characterized in that the electron transport compound has two or more hydrogen bond donor functional groups.

Description

[Technical Field]

[0001] This disclosure relates to a photoelectric conversion element. [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 refers to a battery that absorbs light energy from sunlight and generates current-voltage using 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 toward the practical application of solar cells because of their excellent photoelectric conversion characteristics.

[0007] For example, Patent Document 1 describes a technique that achieves excellent conversion efficiency by curing a perylenediimide compound with an isocyanate compound. Furthermore, Non-Patent Document 1 describes a technique that improves the conversion efficiency of a film material made of a perylenediimide compound by introducing a halogen atom into the molecule of the perylenediimide compound. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2022-2293 [Non-patent literature]

[0009] [Non-Patent Document 1] J.-L.Wu,J.Mater.Chem.A,2017,5,12811. [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] According to our investigations, the photoelectric conversion elements described in Patent Document 1 and Non-Patent Document 1 have room for improvement in suppressing the collapse of the perovskite crystal structure when the element is driven, and in suppressing the intrusion of external molecules such as oxygen and moisture. Therefore, the object of this disclosure is to provide a photoelectric conversion element with improved durability. [Means for solving the problem]

[0011] The above objectives are achieved by the present disclosure below. Specifically, the present disclosure relates to a photoelectric element having a first electrode, a second electrode, a photoelectric conversion layer comprising 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, wherein the electron transport layer contains a cured product of a composition comprising an electron transport compound and a crosslinking agent, and the ASA of the electron transport compound, calculated by the following formulas (1) and (2), is 240 Å. 2or more, wherein the electron-transporting compound has two or more hydrogen bond donor functional groups. This photoelectric conversion element is characterized by the above features.

Mathematical formula

Mathematical formula

Mathematical formula

Mathematical formula

[0012] According to this disclosure, it is possible to provide a photoelectric conversion element with improved durability. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic cross-sectional view in the thickness direction of one embodiment of the photoelectric conversion element of the present disclosure. [Figure 2] This is a schematic perspective view showing 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 embodiment of a building material equipped with a photoelectric conversion element according to the present disclosure. [Modes for carrying out the invention]

[0014] <One Embodiment> One embodiment relates to a 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, wherein the electron transport layer contains a cured product of a composition containing an electron transport compound and a crosslinking agent, and the ASA of the electron transport compound, calculated by the following formulas (1) and (2), is 240 Å. 2 The above is characterized in that the electron-transporting compound has two or more hydrogen bond donor functional groups.

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[0015] As a result of their investigation, the inventors have found that the above configuration results in a photoelectric conversion element with excellent durability. Although the details of why a photoelectric conversion element with excellent durability is obtained in this disclosure are not clear, it is thought to be as follows.

[0016] Because perovskite crystals are composed of ions, they are known to be very brittle and easily fractured by the effects of heat, light, electric fields, and the intrusion of oxygen and moisture from the outside. To improve the durability of photoelectric conversion elements, it is important to suppress ion migration caused by the collapse of the perovskite crystal, but conventional technologies have had difficulties in suppressing ion migration.

[0017] Furthermore, it is recognized that degradation due to chemical reactions caused by oxygen and moisture entering from outside the element and reaching the perovskite crystal structure is a serious problem. The inventors believe that a function to suppress the migration of ions and molecules in the electron transport layer is important for improving the durability of photoelectric conversion elements.

[0018] Patent Document 1 revealed that while the electron transport layer reduces the intermolecular distance by containing a cured product of a composition containing an electron transport compound, it lacks the ability to suppress ion migration detached from the perovskite crystal and to suppress the intrusion of oxygen and water from outside the device.

[0019] Furthermore, even when an electron-transporting compound has one hydrogen bond donor functional group, we believe that the three-dimensional entanglement of hydrogen bonds between molecules is small, which is insufficient for suppressing ion migration after detachment from the perovskite crystal and for suppressing the intrusion of oxygen and water from outside the device.

[0020] Non-patent document 1 states that the electron-transporting compound ASA is 240 Å. 2 As described above, while the interaction area expands as the surface area of ​​the molecule increases, our investigations have shown that the intermolecular gaps become larger due to the larger size of the molecule itself, resulting in insufficient ion transfer and interaction with other molecules.

[0021] The present inventors have found that the electron transport layer contains a cured product of a composition containing an electron transport compound, wherein the ASA of the electron transport compound is 240 Å. 2Based on the above findings, we discovered that the electron-transporting compound, by possessing two or more hydrogen bond donor functional groups, improves the suppression of ion migration detached from the perovskite crystal and the suppression of oxygen and water intrusion from outside the device. This is thought to have improved the durability of the device.

[0022] In this disclosure, an electron-transporting compound is sometimes described as an N-type semiconductor compound that can efficiently transport electrons, or as a compound whose Fermi level approaches the conduction band or the lowest unoccupied orbital (LUMO).

[0023] 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).

[0024] Furthermore, in this disclosure, the electron transport layer may be described as a layer containing an electron transport compound that efficiently transports electrons, a layer containing an N-type semiconductor compound, or a layer containing a compound whose Fermi level is close to the conduction band or the lowest unoccupied orbital (LUMO).

[0025] 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.

[0026] Step 2: Calculate the combination For each bond within the molecule, a scaling factor b is applied according to the type of bond. ij Calculate.

[0027] Step 3: Calculation of atomic contributions Contribution A of each atom i iThe 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.

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[0028] Step 4: Calculation of total surface area The ASA value can be calculated by summing the contributing surface areas of each atom.

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[0029] 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.

[0030] 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.

[0031] When the electron transport layer contains a cured product of a composition containing an electron transport compound, and the electron transport compound has two or more hydrogen bond donor functional groups, the ASA value is 240 Å. 2 Based on the above, it was found that a large molecular surface area is created that facilitates three-dimensional interaction of hydrogen bonds between molecules, and that hydrogen bonding can effectively suppress the movement of ions and molecules.

[0032] ASA is 500Å 2 If the value is larger than this, the spacing between hydrogen bonds and hardening points relative to the surface area of ​​the molecule becomes wider, which may make it easier for ions and molecules to pass through gaps. The photoelectric conversion element of this disclosure uses an ASA of 240 Å to capture migrating ions and molecules, based on the ratio of hydrogen bonds and hardening points to the surface area of ​​the molecule. 2 Above 500 Å 2 The following is preferable: Based on the balance of hydrogen bonds and hardening points relative to the molecular surface area, 270 Å 2 The above 450 Å 2 The following is more preferable: 300 Å 2 The above 400 Å 2 The following are preferable.

[0033] Our studies have shown that a composition containing an electron-transporting compound contains a cured product, and the electron-transporting compound has an ASA value of 240 Å. 2 Even with the above findings, it was found that if an electron-transporting compound has only one hydrogen bond donor functional group, the number of hydrogen bond donor functional groups is insufficient, resulting in a low density of hydrogen bonds spreading three-dimensionally.

[0034] In this disclosure, hydrogen-bonding donor functional groups include hydroxyl groups, phenol groups, carboxyl groups, amino groups, ureido groups, thiol groups, guanidino groups, hydantoin groups, urea groups, sulfonamide groups, sulfonic acid groups, pyrrole groups, piperazine groups, carbamoyl groups, oxime groups, hydrazine groups, and phosphonic acid groups. From the viewpoint of interacting with ions and molecules, hydroxyl groups, carboxyl groups, amino groups, thiol groups, phosphonic acid groups, and phenol groups are preferred. From the strength of hydrogen bonding, hydroxyl groups, carboxyl groups, amino groups, and thiol groups are more preferred, with hydroxyl groups and carboxyl groups being even more preferred.

[0035] In the photoelectric conversion element of the present disclosure, it is preferable that the hydrogen bond donor functional group is at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a thiol group.

[0036] The photoelectric conversion element of the present disclosure preferably contains at least one compound selected from the group consisting of isocyanate compounds, melamine compounds, guanamine compounds, and acid anhydride compounds, from the viewpoint of ease of hydrogen bond formation at the hardening point, and more preferably contains at least one compound selected from the group consisting of isocyanate compounds, melamine compounds, and guanamine compounds.

[0037] From the viewpoint of interacting more strongly with the migrated ions and molecules, isocyanate compounds, melamine compounds, and guanamine compounds having hydrogen bond donor hardening sites are more preferred, with isocyanate compounds being even more preferred.

[0038] Furthermore, isocyanate compounds, melamine compounds, and guanamine compounds having hydrogen bond donor hardening points are more preferable in that they form reversible hydrogen bonds with respect to thermal expansion and bending stress with adjacent layers, thereby dispersing stress and allowing them to adhere closely to adjacent layers and interact more easily with migrating molecules and ions even when the external environment changes, with isocyanate compounds being more preferable.

[0039] In particular, when photoelectric conversion layers containing a perovskite structure are adjacent to each other, the photoelectric conversion layers containing the perovskite structure have ionic properties, and therefore, the above-mentioned stress dispersion effect can be significantly obtained through hydrogen bonding.

[0040] Furthermore, hardening allows the hydrogen bonding sites of the electron-transporting compound to expand spatially, enabling stronger electrical interaction with the underlying layer. This also makes face-on orientation of the aromatic ring of the electron-transporting compound more likely to occur. For these reasons, isocyanate compounds, melamine compounds, and guanamine compounds having hydrogen bond donor hardening sites are more preferred, with isocyanate compounds being the most preferred.

[0041] In particular, when the photoelectric conversion layer contains an ionic crystalline perovskite structure in the lower layer, face-on orientation of the aromatic rings of electron-transporting compounds is more predominantly induced because significant electrical interaction can occur via hydrogen bonding.

[0042] The electron transport layer contains a cured product of a composition containing an electron transport compound, the electron transport compound having two or more hydrogen bond donor functional groups, and having an ASA value of 240 Å. 2 As described above, it has been found that when the composition contains a resin having hydrogen bond donor functional groups, a more spatially complex and stronger network of hydrogen bonds can be constructed within the electron transport layer film. In the photoelectric conversion element of this disclosure, it is preferable that the composition contains a resin having hydrogen bond donor functional groups.

[0043] In this disclosure, hydrogen bond donor functional groups include hydroxyl groups, phenol groups, carboxyl groups, amino groups, ureido groups, thiol groups, guanidino groups, hydantoin groups, urea groups, sulfonamide groups, sulfonic acid groups, pyrrole groups, piperazine groups, carbamoyl groups, oxime groups, hydrazine groups, and phosphonic acid groups. From the viewpoint of interacting with ions and molecules, hydroxyl groups, carboxyl groups, amino groups, and thiol groups are preferred. From the strength of hydrogen bonding, hydroxyl groups and carboxyl groups are more preferred.

[0044] The resin having hydrogen bond donor functional groups that may be included in the electron transport layer, the material of the composition is not particularly limited and may have substituents, and examples include polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyacrylic acid (PAA), polymethacrylic acid (PMAA), polyfumaric acid (PFA), polysuccinic acid (PSA), polyadipic acid (PAdA), polyisophthalic acid (PIPA), polyterephthalic acid (PTA), polynaphthalenedicarboxylic acid (PNA), polyphenol resin (PF), and polyvinyl acetal (PVAH), with polyvinyl acetal, polyvinyl butyral, and polyvinyl butyral being particularly preferred.

[0045] The electron transport layer contains a cured product of a composition containing an electron transport compound, the electron transport compound having two or more hydrogen bond donor functional groups, and having an ASA value of 240 Å. 2 In the above case, it is more preferable that the content of the electron-transporting compound in the composition is 40% by mass or more and 90% by mass or less of the total mass in the composition, because a sufficient amount of hydrogen bonds can be formed in the electron transport layer.

[0046] In the photoelectric conversion element of this disclosure, it is preferable that the content of the electron-transporting compound in the composition containing the cured product is 40% by mass or more and 90% by mass or less, relative to the total mass of solids in the composition. In this disclosure, the content can be confirmed by a nuclear magnetic resonance (NMR) spectrometer or a mass spectrometer (e.g., MALDI-TOF-MS or GC-MS).

[0047] If the hydrogen bond density falls below 40% by mass, there is a risk of a decrease in hydrogen bond formation density. On the other hand, if it exceeds 90% by mass, the hardening point decreases, the intermolecular distance widens, and it is thought that gaps are formed through which ions and molecules can pass. Based on the ratio of hydrogen bonds to hardening points in the molecular surface area, a ratio of 50% to 80% by mass is more preferable.

[0048] Furthermore, the present inventors have provided 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, wherein the electron transport layer contains an electron transport compound, and the ASA of the electron transport compound is 255 Å. 2 In summary, we found that the electron-transporting compound having two or more hydrogen bond donor functional groups improves the suppression of ion migration detached from the perovskite crystal and the suppression of oxygen and water intrusion from outside the device.

[0049] In this disclosure, hydrogen bond donor functional groups include hydroxyl groups, phenol groups, carboxyl groups, amino groups, ureido groups, thiol groups, guanidino groups, hydantoin groups, urea groups, sulfonamide groups, sulfonic acid groups, pyrrole groups, piperazine groups, carbamoyl groups, oxime groups, hydrazine groups, and phosphonic acid groups. From the viewpoint of interacting with ions and molecules, hydroxyl groups, carboxyl groups, amino groups, thiol groups, phosphonic acid groups, and phenol groups are preferred. The electron transport layer may or may not contain resins, crosslinking agents, or passivating agents.

[0050] When the electron transport layer contains an electron transport compound, and the electron transport compound has two or more hydrogen bond donor functional groups, the ASA value is 255 Å. 2 Based on the above, it was found that a large molecular surface area is created that facilitates three-dimensional interaction of hydrogen bonds between molecules, and that hydrogen bonding can effectively suppress the movement of ions and molecules.

[0051] ASA is 500Å 2 If the value is larger than this, the spacing of hydrogen bonds relative to the molecular surface area becomes too wide, potentially creating gaps through which ions or molecules can pass. Based on the ratio of hydrogen bonds to the molecular surface area, a value of 255 Å is used to capture the migrating ions or molecules. 2 Above 500 Å 2 Preferably, the following: 300 Å 2 The above 450 Å 2The following is more preferable: 330 Å, from the viewpoint of more effectively interacting with ions and molecules. 2 The above 400 Å 2 The following is more preferable:

[0052] Our studies have shown that when an electron-transporting compound has only one hydrogen bond donor functional group, the electron-transporting compound is contained, and the ASA of the electron-transporting compound is 255 Å. 2 Even in the above cases, it was found that the number of hydrogen bond donor functional groups was insufficient, and the proportion of hydrogen bonds spreading three-dimensionally was low.

[0053] In this disclosure, hydrogen bond donor functional groups include hydroxyl groups, phenol groups, carboxyl groups, amino groups, ureido groups, thiol groups, guanidino groups, hydantoin groups, urea groups, sulfonamide groups, sulfonic acid groups, pyrrole groups, piperazine groups, carbamoyl groups, oxime groups, hydrazine groups, and phosphonic acid groups. From the viewpoint of interacting with ions and molecules, hydroxyl groups, carboxyl groups, amino groups, thiol groups, phosphonic acid groups, and phenol groups are preferred, hydroxyl groups, carboxyl groups, amino groups, and thiol groups are preferred, and hydroxyl groups and carboxyl groups are more preferred.

[0054] In the photoelectric conversion element of this disclosure, it is preferable that the electron transport 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). In this case, it has been found that it captures ions and molecules that have migrated significantly.

[0055] The inventors believe that the electron density of the heteroatoms contained in the following formula framework enables spatially steric hydrogen bonding between molecules, and that strong interactions with incoming ions and molecules can be expected.

[0056] In particular, the compound represented by the following formula (E1) and the compound represented by the following formula (E2) each contain a hydrogen bond acceptor functional group in the molecule, so that hydrogen bonds are formed more firmly in the electron transport layer, which are particularly preferable.

[0057] Furthermore, even when a cured product of a composition containing an electron-transporting compound is contained, the 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), it is considered that the interaction becomes strong due to the influence of the electron density of the heteroatom.

[0058] In particular, since the compound represented by the following formula (E1) and the compound represented by the following formula (E2) each contain a hydrogen bond acceptor functional group in the molecule, hydrogen bonds with curing points can also be formed, and it is considered that the migration of ions and molecules can be more strongly suppressed.

Chemical Formula

Chemical Formula

Chemical Formula

Chemical Formula

[0059] The photoelectric conversion element of the present disclosure is preferably such that, in formula (E1) to formula (E4), R 11 to R 20 , R 21 to R 26 , R 31 to R 34 , and R 41 to R 48 each independently represent a group represented by the following formula (3). -(R a ) m -(R b ) n -R c (3) (In formula (3), m and n each independently represent 0 or 1.) In formula (3), R aR in formula (3) 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 (E5) d They may be linked together to form a ring. The alkylene group may have a branched structure or a linear structure. In formula (3), R b This represents an oxygen atom, a sulfur atom, or a group represented by the following formula (E5). [ka] (In formula (E5), 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 (3) a Or R in equation (3) c They may be connected together to form a ring. In formula (3), 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 (3) a or R in formula (E5) 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 20Two or more of these are functional groups selected from the group consisting of a hydroxyl group, a hydroxyalkyl group having 1 to 3 carbon atoms, a carboxyl group, an amino group, and a thiol group, R 21 ~R 26 Two or more of these are functional groups selected from the group consisting of a hydroxyl group, a hydroxyalkyl group having 1 to 3 carbon atoms, a carboxyl group, an amino group, and a thiol group, R 31 ~R 34 Two or more of these are functional groups selected from the group consisting of a hydroxyl group, a hydroxyalkyl group having 1 to 3 carbon atoms, a carboxyl group, an amino group, and a thiol group, R 41 ~R 48 Two or more of these are functional groups selected from the group consisting of a hydroxyl group, a hydroxyalkyl group having 1 to 3 carbon atoms, a carboxyl group, an amino group, and a thiol group.

[0060] 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 groups, independently of the group shown in formula (3) below, forms tight hydrogen bonds between molecules, from the viewpoint of R 11 ~R 20 , R 21 ~R 26 , R 31 ~R 34 , and R 41 ~R 48 We believe that a larger structure is preferable because it facilitates interaction between the elements.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] Figure 1 is a schematic cross-sectional view showing the configuration of one embodiment of the photoelectric conversion element of the present invention. Figure 1 will be described below. The photoelectric conversion element 1 has, in this order, a second electrode 3, an electron transport layer 4, a photoelectric conversion layer 5 containing a perovskite crystal structure, a hole transport layer 6, and a first electrode 7. The first electrode 7 and the second electrode 3 function as a positive electrode and a negative electrode, respectively, and current can be extracted by connecting both electrodes to an external circuit as appropriate. The photoelectric conversion layer 5 is excited by light incident through the second electrode 3 and the electron transport layer 4, or by light incident from the first electrode 7 side through the hole transport layer 6, generating electrons or holes. As a result, the photoelectric conversion layer 5 generates an electric current between the first electrode 7 and the second electrode 3. Alternatively, a tandem structure forming a series circuit may be created by repeatedly stacking the layers from the second electrode 3 to the first electrode 7 to provide multiple photoelectric conversion layers 5. In this embodiment, either the first electrode 7 or the second electrode 3 may be made in contact with the substrate 2.

[0065] [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.

[0066] The photoelectric conversion element of the present disclosure comprises an electron transport layer containing a cured product of a composition containing an electron transport compound and a crosslinking agent, wherein the ASA of the electron transport compound, calculated by the following formulas (1) and (2), is 240 Å. 2 The above describes an electron-transporting compound having two or more hydrogen bond donor functional groups.

[0067] Furthermore, the photoelectric conversion element of the present disclosure has an electron transport layer containing an electron transport compound, wherein the ASA of the electron transport compound, calculated by the following formulas (1) and (2), is 255 Å. 2 The above describes an electron-transporting compound having two or more hydrogen bond donor functional groups. The chemical substances of this disclosure can be identified by nuclear magnetic resonance (NMR) spectrometers or mass spectrometers (e.g., MALDI-TOF-MS or GC-MS).

[0068] 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.

[0069] 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.

[0070] The coating method involves preparing the coating solution for each layer, applying them in the desired order, and then drying them. These film formation methods can be selected according to the specific requirements of each layer. The following explains each layer.

[0071] 〔substrate〕 The photoelectric conversion element 1 of this disclosure may include a substrate 2, for example, a transparent glass substrate such as soda-lime glass or alkali-free glass, a ceramic substrate, or a transparent plastic substrate. When light is taken in from the first electrode 7 side, the substrate 2 can be made of an opaque material, and when light is taken in from the second electrode 3 side, the substrate 2 is made of a transparent material.

[0072] 〔electrode〕 The photoelectric conversion element disclosed herein has a first electrode and a second electrode. The materials of the first electrode 7 and the second electrode 3 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, and the like.

[0073] 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.

[0074] These materials may be used individually or in combination of two or more. The first electrode 7 and the second electrode 3 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 formed 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 3 is on the light incidence side, the second electrode 3 may be a transparent electrode and the substrate 2 may be a reflective layer.

[0075] The electrode may be a patterned electrode. Furthermore, the photoelectric conversion element of this disclosure may have a passivate layer formed on the first electrode 7. The passivate material is not particularly limited, but Al2O3 is preferred from the viewpoint of electrode surface treatment ability.

[0076] [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 [α]. A o B p X q [α] In the above general formula [α], A is a cation, B is a cation, and X is an anion.

[0077] 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.

[0078] 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 with three-dimensional and two-dimensional perovskite structures, or a mixed three-dimensional / two-dimensional perovskite crystal, all of which function as photoelectric conversion layers.

[0079] 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.

[0080] 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.

[0081] The cation A in the above general formula [α] is not particularly limited. The organic cation A may or may not have substituents, and specific examples include the following formulas (C1) to (C96). [ka] [ka] [ka] [ka]

[0082] 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.

[0083] In the general formula [α] 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.

[0084] In the general formula [α] above, 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.

[0085] In particular, halogen atoms are preferred because the inclusion of halogens in the structure makes the perovskite crystals more soluble in organic solvents, enabling their application to inexpensive printing methods and the like. Furthermore, iodine is more preferred because it narrows the energy band gap of the perovskite crystals.

[0086] Specifically, 3D perovskites, 2D perovskites, and mixed 3D-2D perovskites are MAPbI3, FAPbCl3, FAPbI3, and 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, MASnI3 are preferred.

[0087] 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.

[0088] Depending on the purpose, the A site, B site, or 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 combinations of x1 to x5 are shown in Table 1. 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.

[0089] [Table 1]

[0090] 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 change easily, thereby increasing the electron mobility in the perovskite crystal and improving the photoelectric conversion efficiency of the photoelectric conversion element.

[0091] 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.

[0092] 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 is 5 nm or more, light can be absorbed sufficiently, and if it is 2000 nm or less, the generated charge can be transported to each electrode. A more preferable lower limit is 50 nm or more, a more preferable upper limit is 1200 nm, an even more preferable lower limit is 100 nm, and an even more preferable upper limit is 1000 nm.

[0093] Furthermore, the photoelectric conversion element of this disclosure may have a passivate layer formed in or adjacent to the photoelectric conversion layer 5. The passivate material is not particularly limited and includes organic salts, inorganic salts, ionic liquids, and resins. The conductivity of the passivate material is not particularly limited and may be either insulating or conductive.

[0094] As organic salts, compounds 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 the following formulas (A1) to (A29) are preferred. [ka]

[0095] 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.

[0096] 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, cesium, barium, rubidium, molybdenum, and ruthenium.

[0097] 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. [ka] R 01 ~R 04 , independently represent a hydrogen atom, an optional alkyl group, and an optional arene group.

[0098] 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-artenalyl) (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.

[0099] [Hole transport layer] In the photoelectric conversion element of this disclosure, a hole transport layer 6 may be arranged between the first electrode 7 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.

[0100] The hole transport layer can be formed by preparing a coating solution for the hole transport layer containing the above-mentioned materials and solvents, 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.

[0101] 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 6 film, a second hole transport layer may be further provided between the hole transport layer 6 and the first electrode 7.

[0102] The material of the hole transport layer 6 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, triazaatorucene compounds, cyclooctatetraene compounds, squalate compounds, etc.

[0103] In particular, it is preferable that the compound has an aromatic ring from the viewpoint of compatibility at the membrane interface, and Spiro-OMeTAD, PTAA, TAPyr, TPD, PEDOT:PSS, Meo-TPD, Poly-TPD, EH44, BTT-DPP, NiOx, CuSCN, V2O5, MnO3, CoOx, WO3, Fe2O3, Cu2O, Ag2S, CuI, phenothiazine compounds, carbazole compounds, triphenylamine compounds, triazaalkene compounds, cyclooctatetraene compounds, and squalate compounds are preferred.

[0104] Furthermore, a passivation material may be provided in or on the hole transport layer 6. The passivation material is not particularly limited and can be an organic salt, an inorganic salt, an ionic liquid, or a resin. The conductivity of the passivation material is not particularly limited and can be either insulating or conductive. Al2O3 is preferred from the viewpoint of surface treatment ability of the electrode and the hole transport layer.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] 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 optional alkyl group, and an optional arene group.

[0109] 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-artenalyl) (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.

[0110] [Electron transport layer] In this disclosure, the electron transport layer 4 contains a cured product of a composition containing an electron transport compound, wherein the ASA of the electron transport compound is 240 Å. 2As described above, the electron-transporting compound has two or more hydrogen bond-donating functional groups and is disposed between the second electrode 3 and the photoelectric conversion layer 5. As for the thickness of the electron transport layer 4, a preferable lower limit is 1 nm, and a preferable upper limit is 2000 nm.

[0111] When the thickness of the electron transport layer 4 is 1 nm or more, holes can be sufficiently blocked, and when the thickness is 2000 nm or less, resistance during electron transport is less likely to occur, leading to higher photoelectric conversion efficiency. A more preferable lower limit of the thickness is 1 nm, a more preferable upper limit is 1000 nm, a still more preferable lower limit is 1 nm, and a still more preferable upper limit is 500 nm.

[0112] Further, in the present disclosure, the electron transport layer 4 contains an electron-transporting compound, and the ASA of the electron-transporting compound is 255 Å 2 or more, the electron-transporting compound has two or more hydrogen bond-donating functional groups and is disposed between the second electrode 3 and the photoelectric conversion layer 5.

[0113] As for the thickness of the electron transport layer 4, a preferable lower limit is 1 nm, and a preferable upper limit is 2000 nm. When the thickness of the electron transport layer 4 is 1 nm or more, holes can be sufficiently blocked, and when the thickness is 2000 nm or less, resistance during electron transport is less likely to occur, leading to higher photoelectric conversion efficiency. A more preferable lower limit of the thickness is 1 nm, a more preferable upper limit is 1000 nm, a still more preferable lower limit is 1 nm, and a still more preferable upper limit is 500 nm.

[0114] In the present disclosure, the electron-transporting compound refers to a compound that can efficiently transport electrons, may be expressed as an N-type semiconductor compound, or may be described such that the Fermi level of the compound is close to the conduction band or the lowest unoccupied molecular orbital (LUMO).

[0115] 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).

[0116] Furthermore, in this disclosure, the electron transport layer may be described as a layer containing an electron transport compound that efficiently transports electrons, a layer containing an N-type semiconductor compound, or a layer containing a compound whose Fermi level is close to the conduction band or the lowest unoccupied orbital (LUMO).

[0117] [Electron transport compound] Examples of electron-transporting compounds include perylenediimide derivatives, fullerene derivatives, naphthalenediimide derivatives, anthraquinone derivatives, fluorenone derivatives, phenanthrenequinone derivatives, benzimidazoperylene derivatives, benzimidazonaphthalene derivatives, phthalocyanine derivatives, diphenoquinone derivatives, naphthoquinone derivatives, azaacene derivatives, indasenodithiophene derivatives, benzothiadiazole derivatives, triazine derivatives, heteroarene derivatives, quinone derivatives, acridine derivatives, carbazole derivatives, phenanthroline derivatives, dicyanomethylene derivatives, azomethine derivatives, thioxanthone derivatives, pyrimidine derivatives, pyrazine derivatives, pyridine derivatives, imidazole derivatives, indole derivatives, thiophene derivatives, selenphene derivatives, phenazine derivatives, anthraquinozone derivatives, oxadiazole derivatives, pyrrole derivatives, pyrrolidine derivatives, and fluorene derivatives.

[0118] Among these, perylenediimide derivatives, naphthalenediimide derivatives, fullerene derivatives, azaacene derivatives, and indasenodithiophene derivatives are particularly preferred, and the compounds represented by the following formula (E1), the compounds represented by the following formula (E2), the compounds represented by the following formula (E3), and the compounds represented by the following formula (E4) are more preferred. [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 hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 28 carbon atoms, an arylalkyl group having 7 to 28 carbon atoms, a halogen atom, a cyano group, a nitro group, an aldehyde group, a ketone group, an ester group, a sulfone group, an azo group, an ether group, an imino group, a nitrile group, or a hydrogen bond donor functional group. 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 Two or more of these include a hydrogen bond donor functional group, R 21 ~R 26 Two or more of these include a hydrogen bond donor functional group, R 31 ~R 34 Two or more of these include a hydrogen bond donor functional group, R 41 ~R 48 Two or more of these contain hydrogen bond donor functional groups.

[0119] In formulas (E1) to (E4), R 11 ~R 20 , R 21 ~R26 , R 31 ~R 34 , and R 41 ~R 48 It is more preferable that each of these groups is independently represented by the following formula (3). -(R a ) m -(R b ) n -R c (3)

[0120] In equation (3), m and n are independently either 0 or 1. In formula (3), R a R in formula (3) 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 (E5) d They may be linked together to form a ring. The alkylene group may have a branched structure or a linear structure.

[0121] In formula (3), R b This represents an oxygen atom, a sulfur atom, or a group represented by the following formula (E5). [ka] (In formula (E5), R d R represents a hydrogen atom, or an alkyl group having 1 to 4 substituted or unsubstituted carbon atoms, or R in formula (3). a Or R in equation (3) c They may be connected together to form a ring.

[0122] In formula (3), R c R in formula (3) 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, or R in formula (3) a or R in formula (E5) d They may be connected to each other to form a ring.

[0123] The substituents that the alkylene group and the alkyl group may have are a hydroxy group, a carboxy 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.

[0124] The substituents that the arylene group, the aryl group and the arylalkyl group may have are an alkyl group having 1 to 3 carbon atoms, a hydroxy group, a hydroxyalkyl group having 1 to 3 carbon atoms, a carboxy group, an amino group, a thiol group, an alkoxy group having 1 to 3 carbon atoms, an alkoxycarbonyl group having 2 to 4 carbon atoms, a halogen atom, a cyano group, and a nitro group.

[0125] Provided that R 11 to R 20 two or more thereof are functional groups selected from the group consisting of a hydroxy group, a hydroxyalkyl group having 1 to 3 carbon atoms, a carboxy group, an amino group, and a thiol group, and R 21 to R 26 two or more thereof are functional groups selected from the group consisting of a hydroxy group, a hydroxyalkyl group having 1 to 3 carbon atoms, a carboxy group, an amino group, and a thiol group, and R 31 to R 34 two or more thereof are functional groups selected from the group consisting of a hydroxy group, a hydroxyalkyl group having 1 to 3 carbon atoms, a carboxy group, an amino group, and a thiol group, and R 41 to R 48 two or more thereof are functional groups selected from the group consisting of a hydroxy group, a hydroxyalkyl group having 1 to 3 carbon atoms, a carboxy group, an amino group, and a thiol group.)

[0126] Hereinafter, specific examples of the n-type organic semiconductor are shown, but the present invention is not limited to these examples.

Chemical Formula

Chemical Formula

[0127] Methods for introducing polymerizable functional groups into electron-transporting compounds include, for example, directly introducing polymerizable functional groups into the synthesized skeleton, introducing structures having polymerizable functional groups or functional groups that can serve as precursors to polymerizable functional groups (for example, using a halide of a perylenediimide derivative and employing a cross-coupling reaction using a palladium catalyst and a base, or a cross-coupling reaction using an FeCl3 catalyst and a base), and using a perylenetetracarboxylic dianhydride derivative or monoamine derivative having a polymerizable functional group or a functional group that can serve as a precursor to polymerizable functional groups as a starting material when synthesizing perylenediimide derivatives.

[0128] Furthermore, in this disclosure, from the viewpoint of the compatibility of the electron transport layer 4 film, a second electron transport layer may be provided between the electron transport layer 4 and the second electrode 3, or between the photoelectric conversion layer 5 and the electron transport layer 4.

[0129] 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, etc. Specifically, examples include perylenediimide derivatives, fullerene derivatives, naphthalenediimide derivatives, anthraquinone derivatives, fluorenone derivatives, phenanthrenequinone derivatives, benzimidazoperylene derivatives, benzimidazonaphthalene derivatives, phthalocyanine derivatives, diphenoquinone derivatives, naphthoquinone derivatives, azacene derivatives, indasene Examples include nodithiophene derivatives, benzothiadiazole derivatives, triazine derivatives, heteroarene derivatives, quinone derivatives, acridine derivatives, carbazole derivatives, phenanthroline derivatives, dicyanomethylene derivatives, azomethine derivatives, thioxanthone derivatives, pyrimidine derivatives, pyrazine derivatives, pyridine derivatives, imidazole derivatives, indole derivatives, thiophene derivatives, selenphene derivatives, phenazine derivatives, anthraquinozone derivatives, oxadiazole derivatives, pyrrole derivatives, pyrrolidine derivatives, and fluorene derivatives.

[0130] Among these, perylenediimide derivatives, naphthalenediimide derivatives, fullerene derivatives, azaacene derivatives, indasenodithiophene derivatives, titanium dioxide, zinc oxide, indium oxide, tin oxide, gallium oxide, tin sulfide, indium sulfide, aluminum-doped zinc oxide (AZO), zinc-tin oxide (ZTO), 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.

[0131] The electron transport layer composition may contain a crosslinking agent, and any known material can be used as the crosslinking agent.

[0132] The crosslinking agent is preferably an acid anhydride derivative, a phenol compound, an amine compound, an isocyanate compound having an isocyanate group or a blocked isocyanate group, or an amine compound having an N-methylol group or an alkyl etherified N-methylol group. More preferably, an isocyanate compound having 3 to 6 isocyanate groups or blocked isocyanate groups.

[0133] Examples of isocyanate compounds include, but are not limited to, the isocyanate compounds listed below. Furthermore, multiple isocyanate compounds may be used in combination.

[0134] Examples include triisocyanate benzene, triisocyanate methylbenzene, triphenylmethane triisocyanate, isocyanurate modified compounds, biuret modified compounds, biuret-type isocyanates, allophanate modified compounds, and adduct modified compounds with trimethylolpropane or pentaerythritol. A blocked isocyanate group is a group having the structure -NHCOX1 (where X1 is a protecting group). X1 can be any protecting group that can be introduced into an isocyanate group.

[0135] Examples of commercially available isocyanate compounds include isocyanate-based crosslinking agents such as Duranate MFK-60B, SBA-70B, 17B-60P, SBN-70D, SBB-70P (manufactured by Asahi Kasei Corporation), Cosmonate TM-20, TM-50 (manufactured by Mitsui Chemicals, Inc.), and Bronate 1227EV, 1232P, 1902V, 1961V (manufactured by Daiei Sangyo Co., Ltd.).

[0136] Amine compounds having multiple (three or more) N-methylol groups or alkyl etherified N-methylol groups are more preferred. Examples include methylolated melamine, methylolated guanamine, methylolated urea derivatives, methylolated ethyleneurea derivatives, methylolated glycoluryl, compounds in which the methylol moiety is alkyl etherified, and derivatives thereof. Methylolated melamine and methylolated guanamine are even more preferred.

[0137] Examples of commercially available amine compounds include melamine compounds such as Yuban 20SB, 2020, 60R, and 360 (manufactured by Mitsui Chemicals, Inc.), and Nikalac MW-30M, MW-11, and MX-750 (manufactured by Sanwa Chemical Co., Ltd.). Examples of guanamine compounds include Nikalac BL-60 and BX-4000 (manufactured by Sanwa Chemical Co., Ltd.).

[0138] The electron transport layer composition may further contain an electron transport material, a crosslinking agent, and a resin polymerizable by the crosslinking agent. Examples of resins include polyacetal resin, polyvinyl acetal resin, and Examples include polyolefin resins, polyester resins, polyether resins, and polyamide resins. Functional groups that can be polymerized by the crosslinking agent include hydroxyl groups, carboxyl groups, amino groups, and thiol groups.

[0139] Examples of commercially available resins having functional groups that can be polymerized with the aforementioned crosslinking agent 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.).

[0140] The weight-average molecular weight of the resin having polymerizable functional groups with the aforementioned crosslinking agent 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.

[0141] 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.

[0142] 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.

[0143] Furthermore, a passivation layer may be provided on top of the electron transport layer 4. The passivation material is not particularly limited and can be an organic salt, an inorganic salt, or an ionic liquid. The conductivity of the passivation material is not particularly limited and can be either insulating or conductive.

[0144] 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.

[0145] 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.

[0146] 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, cesium, barium, rubidium, molybdenum, and ruthenium.

[0147] 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 optional alkyl group, and an optional arene group.

[0148] Furthermore, from the viewpoint of electron injection, an electron injection layer may be provided on the electron transport layer or a second electron transport layer. The material of the electron injection layer is not particularly limited, and for example, bathocuproine, bathophenanthroline, perylenedimid derivatives, and naphthalenediimide derivatives are preferred, with bathocuproine and bathophenanthroline being particularly preferred due to their energy levels.

[0149] <Application Examples> Examples of applications of this disclosure include photoelectric converters, mobile devices, and building materials. [Photoelectric converter] The photoelectric conversion device disclosed herein has the above-described photoelectric conversion element. A photoelectric conversion device can be configured by using multiple photoelectric conversion elements of the present disclosure. 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.

[0150] 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.

[0151] 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.

[0152] [Mobile] The mobile body of the present disclosure has the above-mentioned photoelectric conversion element. Figure 2 is a schematic perspective view showing one embodiment of the mobile body equipped with the photoelectric conversion element of the present disclosure. The mobile body 30 has the photoelectric conversion element 31 of the present disclosure and a body 32 equipped with the photoelectric conversion element 31.

[0153] The photoelectric conversion element 31 is positioned in a location on the body 32 where it can receive ambient light. 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.

[0154] 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.

[0155] 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.

[0156] [Building materials] The building material of this disclosure has the above-described photoelectric conversion element. Figure 3 is a schematic perspective view showing one embodiment of the building material of this disclosure equipped with the photoelectric conversion element. The building material 40 may be the roof of a building. The building material 40 of this embodiment has the photoelectric conversion element 41 of this disclosure, a protective member 42 for protecting the photoelectric conversion element 41, a heat dissipation member 43, and exterior parts 44a, 44b.

[0157] The building material 40 of this disclosure may have a heat dissipation member 43 with a higher thermal conductivity than the photoelectric conversion element 41. When used on roofs, etc., the temperature of the photoelectric conversion element 41 may rise due to sunlight, which may reduce the photoelectric conversion efficiency. By using the heat dissipation member 43, the decrease in photoelectric conversion efficiency can be reduced. Examples of the heat dissipation member 43 include metals, alloys, liquid metals, liquid resins, etc.

[0158] Furthermore, the building material 40 of this disclosure may have exteriors 44a and 44b. Exteriors 44a and 44b may have different colors or the same color. 44a and 44b may be composed of the same material or different materials. As the exterior, paint or a transparent substrate may be used. It is preferable that the exterior has low light absorption and high heat shielding properties.

[0159] 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. Sheet structures supported by multiple frames include tents, greenhouses, and truck beds. Fixed structures 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.

[0160] <Manufacturing method for photoelectric conversion elements> The present invention provides a method for manufacturing a photoelectric conversion element, comprising the steps of: forming a first electrode; forming a second electrode; forming a photoelectric conversion layer containing a perovskite crystal between the first electrode and the second electrode; and forming an electron transport layer between the photoelectric conversion layer and the second electrode. The following describes each step of the manufacturing process.

[0161] [Steps for forming the first electrode and steps for forming the second electrode] In the process of forming the first electrode and the process of forming the second electrode, an appropriate method can be selected depending on the material of the first electrode and the material of the second electrode, respectively. Examples of such methods include, but are not limited to, sputtering, vacuum deposition, CVD (vapor deposition), and SPD (spray pyrolysis deposition). The materials of the first and second electrodes are as described above. When either or both of the first and second electrodes are transparent electrodes, the thickness of the transparent electrode is preferably 0.03 μm or more and 3 μm or less.

[0162] [Modularization Process] When manufacturing solar cells, cutting processes may be performed between each manufacturing step to form circuits. Examples of cutting processes include mechanical patterning and laser patterning. 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. 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.

[0163] [Process for forming the photoelectric conversion layer] The photoelectric conversion layer formation process may include a step of applying a liquid containing the above-mentioned photoelectric conversion layer material. Examples of application methods include spin coating, blade coating, slit die coating, screen printing, bar coating, mold making, print transfer, immersion and pull-up, inkjet, spray, and vacuum deposition. From these options, appropriate choices are made depending on the characteristics of the photoelectric conversion layer to be fabricated, such as thickness control and orientation control. Annealing treatment may be performed under reduced pressure or in an inert atmosphere (nitrogen or argon atmosphere) to remove the solvent or dispersion medium from the liquid containing the material of the applied photoelectric conversion layer. The temperature of the annealing treatment is preferably 40°C to 300°C, and more preferably 50°C to 150°C. Annealing treatment is preferable because it can increase the contact area at the interface between the stacked layers, as the materials constituting each layer penetrate each other, which can increase the short-circuit current.

[0164] [Process for forming the electron transport layer] A preferred method for forming the electron transport layer is to apply a liquid containing the electron transport layer material described above. Examples of application methods include spin coating, blade coating, slit die coating, screen printing, bar coating, molding, print transfer, immersion and pull-up, inkjet, spray, and vacuum deposition. [Examples]

[0165] 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.

[0166] (Example 1) [Hole transport layer formation] A square glass substrate with ITO, measuring 25 mm on each side, was cleaned. 3PATAT-3C (manufactured by Tokyo Chemical Industry Co., Ltd.) was then prepared by mixing it with 100 mL of N,N-dimethylformamide (DMF) to a concentration of 0.01 mM. This solution was then applied by spin coating, and the substrate was heated at 110°C for 10 minutes to form a thin-film hole transport layer.

[0167] [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 uL of DMF and 252.4 uL of dimethyl sulfoxide (DMSO) and stirred for 2 hours (Solution 1). Furthermore, 0.036 g of cesium iodide was dissolved in 96.6 uL of DMSO and stirred for 2 hours (Solution 2).

[0168] Subsequently, the dissolved cesium iodide solution (Solution 2) was added to Solution 1 to prepare a 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 a 600 nm thick photoelectric conversion layer consisting of Cs0.05FA0.88MA0.05PbI2.84Br0.14.

[0169] [Formation of the passivation layer] 2-phenylethylamine hydroiodide (PEAI) was prepared in 2-propanol (IPA) at a concentration of 1 mg / mL. The solution was applied by spin coating to obtain a passivation layer.

[0170] [Formation of the electron transport layer] The electron transport layer coating solution was prepared using the following procedure and spin-coated onto the photoelectric conversion layer at 2500 rpm. The solution was then heated at 140°C for 60 minutes to deposit an electron transport layer with a thickness of approximately 20 nm. The electron transport layer coating solution was prepared considering the desorbing block groups, ensuring that the electron transport compound accounted for 60% by mass of the total mass of the electron transport layer after deposition.

[0171] 6.00 parts of the following compound (PD1) as an electron transport compound, 0.10 parts of polyolefin resin (product name: UC-3920, manufactured by Toagosei Co., Ltd.) and 0.10 parts of polyvinyl acetal resin (product name: KS-5Z, manufactured by Sekisui Chemical Co., Ltd.) as resins, and 8.20 parts of a blocked isocyanate compound (product name: SBB-70P, manufactured by Asahi Kasei Corporation) as a crosslinking agent were dissolved in a mixed solvent of 670 parts THF / 330 parts orthoxylene.

[0172] Subsequently, the mixture was pressure filtered using an ADVANTEC Teflon® filter (product name: PF020). The resulting electron transport layer coating solution was spin-coated onto the photoelectric conversion layer at 2500 rpm. Then, it was heated at 140°C for 30 minutes to form an electron transport layer with a thickness of approximately 20 nm. [ka]

[0173] [Formation of electron injection layer] Vasocuproine (BCP) was prepared in IPA at a concentration of 0.5 mg / mL. This solution was applied by spin coating to obtain an electron injection layer.

[0174] [Formation of the second electrode] On the aforementioned electron transport layer, an area of ​​0.09 cm² 2 Ten Ag electrodes were formed to obtain a photoelectric conversion element.

[0175] [Analysis of compound amounts] The electrode surface of the photoelectric conversion element was stripped to expose the electron transport layer surface. The electron transport compound was removed from this electron transport layer surface by wiping it with a cotton swab soaked in solvent, dissolved in heavy DMSO, and 1H-NMR measurement was performed (instrument: BRUKER AVANCE3-500).

[0176] Furthermore, the presence of the electron-transporting compound was confirmed by mass and structural analysis of the stripped-off electron-transporting compound using GPC, MALDI-TOF-MS, IR, gas chromatography, XPS, EDX, and other elemental analyses. The ASA of the electron-transporting compound was calculated using the Python language and the RDKit library after creating a Smiles model of the structural formula. Furthermore, the film thickness was confirmed by cutting the photoelectric conversion element, fixing it on an inclined sample stage, and then using a cross-sectional SEM (equipment: Carl Zeiss GmbH, SmartSEM).

[0177] (Examples 2-5 and Example 8) For Examples 2-5 and Example 8, the photoelectric conversion element is obtained in the same manner as in Example 1, except for the modifications shown in Table 1.

[0178] (Example 9) A photoelectric conversion element is obtained in the same manner as in Example 1, except that compound (PD1) is not used as the electron transport compound, and (PD2):(PD9):(PD10) are mixed in a ratio of 1:2:1.

[0179] (Examples 10-17 and 22-25) Examples 10-17 and Examples 22-25 are obtained in the same manner as in Example 1, except for the modifications shown in Table 1.

[0180] (Example 27) A photoelectric conversion element is obtained in the same manner as in Example 1, except that polyolefin resin and polyvinyl acetal resin are not used as resins in the formation of the electron transport layer.

[0181] (Example 28) A photoelectric conversion element is obtained in the same manner as in Example 1, except that in the formation of the electron transport layer, a blocked isocyanate compound is not used as a crosslinking agent, and instead 2020 (manufactured by Mitsui Chemicals, Inc.) is used.

[0182] (Example 29) A photoelectric conversion element is obtained in the same manner as in Example 1, except that a blocked isocyanate compound is not used as a crosslinking agent in the formation of the electron transport layer, and instead Nikkalac BL60 (manufactured by Sanwa Chemical Co., Ltd.) is used.

[0183] (Example 30) A photoelectric conversion element is obtained in the same manner as in Example 1, except that 6.00 parts of the example compound (PD1) from Table 1, 1.20 parts of polyvinyl acetal resin (product name: KS-5Z, manufactured by Sekisui Chemical Co., Ltd.) as the resin, and 2.80 parts of phthalic anhydride as a crosslinking agent are dissolved in a mixed solvent of 670 parts THF / 330 parts orthoxylene.

[0184] (Example 31) A photoelectric conversion element is obtained in the same manner as in Example 1, except that a blocked isocyanate compound (product name: SBN-70D, manufactured by Asahi Kasei Corporation) is used as a crosslinking agent instead of a blocked isocyanate compound (product name: SBB-70P, manufactured by Asahi Kasei Corporation) in the formation of the electron transport layer.

[0185] (Example 32) A photoelectric conversion element is obtained in the same manner as in Example 1, except that a second electron transport layer is formed using PCBM after the formation of the aforementioned electron transport layer.

[0186] (Example 33) After the electron transport layer is formed, C 60 A photoelectric conversion element is obtained in the same manner as in Example 1, except that a second electron transport layer is formed using [the specified method].

[0187] (Example 34) A photoelectric conversion element is obtained in the same manner as in Example 1, except that a second electron transport layer is formed using SnO2 after the formation of the aforementioned electron transport layer.

[0188] (Example 35) A photoelectric conversion element is obtained in the same manner as in Example 1, except that a second electron transport layer is formed using ZnO after the formation of the aforementioned electron transport layer.

[0189] (Example 36) A photoelectric conversion element is obtained in the same manner as in Example 1, except that a second electron transport layer is formed using ZTO after the formation of the aforementioned electron transport layer.

[0190] (Example 37) A photoelectric conversion element is obtained in the same manner as in Example 1, except that a second electron transport layer is formed using AZO after the formation of the aforementioned electron transport layer.

[0191] (Examples A-H) For Examples A to H, the photoelectric conversion element is obtained in the same manner as in Example 1, except for the modifications shown in Table 1.

[0192] (Example 38) A photoelectric conversion element is obtained in the same manner as in Example 1, except that a crosslinking agent and resin are not used in the formation of the electron transport layer.

[0193] (Examples 39-41 and 44) Examples 39-41 and Example 44 are obtained in the same manner as Example 38, except for the modifications shown in Table 1.

[0194] (Example 45) A photoelectric conversion element is obtained in the same manner as in Example 38, except that compound (PD1) is not used as the electron transport compound, and (PD2):(PD9):(PD10) are mixed in a ratio of 1:2:1.

[0195] (Examples 46-53) For Examples 46 to 53, the photoelectric conversion elements are obtained in the same manner as in Example 38, except for the modifications shown in Table 1.

[0196] (Example 58) A photoelectric conversion element is obtained in the same manner as in Example 38, except that 9 parts of the following compound (PD1) as the electron transport compound, 0.5 parts of polyolefin resin (product name: UC-3920, manufactured by Toagosei Co., Ltd.), and 0.5 parts of polyvinyl acetal resin (product name: KS-5Z, manufactured by Sekisui Chemical Co., Ltd.) are dissolved in a mixed solvent of 670 parts THF / 330 parts orthoxylene as the aforementioned electron transport compound, and the photoelectric conversion element is obtained in the same manner as in Example 38.

[0197] (Example 59) A photoelectric conversion element is obtained in the same manner as in Example 38, except that a second electron transport layer is formed using PCBM after the formation of the aforementioned electron transport layer.

[0198] (Example 60) After the electron transport layer is formed, C 60 A photoelectric conversion element is obtained in the same manner as in Example 38, except that a second electron transport layer is formed using [the specified method].

[0199] (Example 61) A photoelectric conversion element is obtained in the same manner as in Example 38, except that a second electron transport layer is formed using SnO2 after the formation of the aforementioned electron transport layer.

[0200] (Example 62) A photoelectric conversion element is obtained in the same manner as in Example 38, except that a second electron transport layer is formed using ZnO after the formation of the aforementioned electron transport layer.

[0201] (Example 63) A photoelectric conversion element is obtained in the same manner as in Example 38, except that a second electron transport layer is formed using ZTO after the formation of the aforementioned electron transport layer.

[0202] (Example 64) A photoelectric conversion element is obtained in the same manner as in Example 38, except that a second electron transport layer is formed using AZO after the formation of the aforementioned electron transport layer.

[0203] (Examples G-N) For Examples G to N, the photoelectric conversion element is obtained in the same manner as in Example 38, except for the modifications shown in Table 1.

[0204] (Example O) In Example O, a photoelectric conversion element is obtained in the same manner as in Example 61, except that an electron transport compound and PEAI of equal weight are added to prepare a coating solution for the electron transport layer, and a passivation layer is not formed.

[0205] (Example P) In Example P, a photoelectric conversion element is obtained in the same manner as in Example 61, except that an electron transport compound and an equal weight of F-PEAI are added to prepare a coating solution for the electron transport layer, and a passivation layer is not formed.

[0206] (Example Q) In Example Q, a photoelectric conversion element is obtained in the same manner as in Example 38, except that an electron transport compound and PEAI of equal weight are added to prepare a coating solution for the electron transport layer, and a passivation layer is not formed.

[0207] (Example R) In Example R, an electron transport layer coating solution was prepared by adding an equal weight of F-PEAI to the electron transport compound, and a photoelectric conversion element was obtained in the same manner as in Example 38, except that a passivation layer was not formed.

[0208] (Comparative Example 1) A photoelectric conversion element was obtained in the same manner as in Example 1, except that the electron transport compound was changed to the compound represented by the following formula (ND10). [ka]

[0209] (Comparative Example 2) A photoelectric conversion element was obtained in the same manner as in Example 1, except that the electron transport compound was changed to the compound represented by the following formula (ND11). [ka]

[0210] (Comparative Example 3) A photoelectric conversion element was obtained in the same manner as in Example 1, except that the electron transport compound was changed to the compound shown in the following formula (PD28). [ka]

[0211] (Comparative Example 4) A photoelectric conversion element was obtained in the same manner as in Example 1, except that the electron transport compound was changed to the compound represented by the following formula (ND12). [ka]

[0212] (Comparative Example 5) A photoelectric conversion element was obtained in the same manner as in Example 1, except that the electron transport compound was changed to the compound represented by the following formula (BT4). [ka]

[0213] (Comparative Example 6) A photoelectric conversion element was obtained in the same manner as in Example 1, except that the electron transport compound was changed to PCBM.

[0214] (Comparative Example 7) A photoelectric conversion element was obtained in the same manner as in Example 1, except that the electron transport compound was changed to the compound represented by the following formula (ND13). [ka]

[0215] (Comparative Example 8) A photoelectric conversion element was obtained in the same manner as in Example 1, except that the electron-transporting compound was changed to the compound shown in the following formula (PD29), and ZnO was formed as a second electron-transporting layer after the electron-transporting layer was formed. [ka]

[0216] (Comparative Example 9) A photoelectric conversion element was obtained in the same manner as in Example 1, except that the electron-transporting compound was changed to PCBM and SnO2 was formed as a second electron-transporting layer after the electron-transporting layer was formed.

[0217] (Comparative Example 10) A photoelectric conversion element was obtained in the same manner as in Example 1, except that the electron-transporting compound was changed to PCBM and ZnO was formed as a second electron-transporting layer after the electron-transporting layer was formed.

[0218] (Comparative Example 11) A photoelectric conversion element was obtained in the same manner as in Example 37, except that the electron transport compound was changed to the compound represented by the following formula (ND14). [ka]

[0219] (Comparative Example 13) A photoelectric conversion element was obtained in the same manner as in Example 37, except that the electron transport compound was changed to the compound shown in the following formula (BT2).

[0220] [evaluation] The photoelectric conversion element fabricated in Example 1 was subjected to a durability test while being exposed to 50°C nitrogen under 1 sun irradiation. After 100 hours, the degree of degradation of the photoelectric conversion element was evaluated using X-ray diffraction measurement.

[0221] A photoelectric conversion element was set in an X-ray diffractometer (Rigaku Corporation, RINT-TTRII) and X-ray diffraction measurements were performed. The measurement conditions were as follows: X-ray tube target: Cu, tube voltage: 50kV, tube current: 300mA, X-ray focus: line, X-ray wavelength: Kα1, optical system: parallel beam method, Kβ filter: none, incident monochromator: present, divergence slit: open, scattering slit: open, receiving slit: open, scanning axis: 2θ / θ, scanning range: 3°~60°, scanning speed: 4° / min, sampling interval: 0.02°, measurement method: continuous, detector: scintillation counter. The degree of element degradation was evaluated from the intensity of the maximum diffraction peak that appeared at a 2θ angle of 14°±1°.

[0222] Furthermore, a power supply (KEITHLEY, Model 236) was connected between the electrodes of the photoelectric conversion element fabricated in Example 1, and the intensity was set to 100 mW / cm². 2 The photoelectric conversion efficiency is measured by irradiating a constant amount of light using a solar simulator (manufactured by Yamashita Densou Co., Ltd.) and measuring the generated current and voltage.

[0223] Furthermore, measurements were taken at each of the 10 electrodes for each photoelectric conversion element, and the average value was used as the representative value for that photoelectric conversion element. The results are shown in Table 1. In Tables 2 and 3, the intensity of the maximum diffraction peak appearing at a 2θ angle of 14°±1° in Example 1 and the photoelectric conversion efficiency are set to 1, and the ratio to this is expressed as the intensity of the maximum diffraction peak appearing at a 2θ angle of 14°±1° for each photoelectric conversion element.

[0224] In Tables 2 and 3, "percentage of electron-transporting compounds in the composition" refers to the percentage of electron-transporting compounds in the composition relative to the total mass of solids in the composition. In Tables 2 and 3, "number" refers to the number of hydrogen bond donor functional groups.

[0225] [Table 2]

[0226] [Table 3]

[0227] This embodiment includes the following configurations and methods. (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 containing an electron transport compound and a crosslinking agent, wherein the ASA of the electron transport compound, calculated by the following formulas (1) and (2), is 240 Å. 2 The above is true, and the electron transport compound has two or more hydrogen bond donor functional groups. A photoelectric conversion element characterized by the following features.

number

number

number

number

number

number

[0228] 1. Photoelectric conversion element 2 circuit boards 3 Second electrode 4 Electron transport layer 5 Photoelectric conversion layer 6. Hole transport layer 7 First 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 containing an electron transport compound and a crosslinking agent, wherein the ASA of the electron transport compound, calculated by the following formulas (1) and (2), is 240 Å. ２ The above is true, and the electron transport compound has two or more hydrogen bond donor functional groups. A photoelectric conversion element characterized by the following features. [Math 1] [Math 2] (In formula (1) and formula (2), R ｉ represents the van der Waals radius of atom i, R ｊ represents the van der Waals radius of atom j. d ｉｊ is the distance between atom i and atom j, and d ｉｊ =min(max(|R ｉ -R ｊ |, b ｉｊ ), R ｉ +R ｊ )).

2. The aforementioned ASA is 300 Å ２ The photoelectric conversion element described in claim 1 is as described above.

3. The photoelectric element according to claim 1, wherein the composition contains at least one compound selected from the group consisting of isocyanate compounds, melamine compounds, and guanamine compounds.

4. The photoelectric element according to claim 1, wherein the composition contains a resin having hydrogen bond donor functional groups.

5. The photoelectric conversion element according to claim 1, wherein the content ratio of the electron transporting compound in the composition is 40% by mass or more and 90% by mass or less with respect to the total mass of solids in the composition.

6. The aforementioned ASA is 500 Å ２ The photoelectric conversion element according to claim 1, which is as follows:

7. 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 an electron transport compound, and the ASA of the electron transport compound, calculated by the following formulas (1) and (2), is 255 Å. ２ The above is true, and the electron transport compound has two or more hydrogen bond donor functional groups. A photoelectric conversion element characterized by the following features. [Math 3] [Math 4] (In equations (1) and (2), R ｉ represents the van der Waals radius of atom i, and R ｊ represents the van der Waals radius of atom j. ｉｊ d is the distance between atom i and atom j, and d ｉｊ =min(max(|R ｉ -R ｊ |, b ｉｊ ), R ｉ +R ｊ It is calculated by ( ).

8. The aforementioned ASA is 300 Å ２ The photoelectric conversion element described in claim 7 is as described above.

9. The aforementioned ASA is 500 Å ２ The photoelectric conversion element according to claim 7, which is as follows:

10. The photoelectric conversion element according to claim 1 or 7, wherein the hydrogen bond donor functional group is at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a thiol group.

11. The photoelectric conversion element according to claim 1 or 7, wherein the 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 the formulas (E1) to (E4), the R １１ ~R ２０ , the R ２１ ~R ２６ , the R ３１ ~R ３４ , and the R ４１ ~R ４８ Each independently represents 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, or a functional group selected from the group consisting of a halogen atom, a cyano group, a nitro group, a formyl group, a carbonyl group, an ester group, a sulfonyl group, an azo group, an oxy group, an imino group, a nitrile group, a phosphoryl group, and a hydrogen bond donor functional group, or a group containing any of these functional groups. In this case, R １１ ~R ２０ , the R ２１ ~R ２６ , the R ３１ ~R ３４ , and the R ４１ ~R ４８ However, adjacent groups may connect to each other and jointly form a ring. However, the R １１ ~R ２０ Two or more of these include a hydrogen bond donor functional group, and the R ２１ ~R ２６ Two or more of these include a hydrogen bond donor functional group, and the R ３１ ~R ３４ Two or more of these include a hydrogen bond donor functional group, and the R ４１ ~R ４８ Two or more of these contain hydrogen bond donor functional groups.

12. In the above formulas (E1) to (E4), the R １１ ~R ２０ , the R ２１ ~R ２６ , the R ３１ ~R ３４ , and the R ４１ ~R ４８ The photoelectric conversion element according to claim 11, wherein each of these is independently a group represented by the following formula (3). -(R ａ ) ｍ -(R ｂ ) ｎ -R ｃ (3) (In formula (3), m and n are each independently 0 or 1.) In formula (3), R ａ R in formula (3) 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 the following formula (E5) ｄ They may be connected to each other to form a ring. In formula (3), R ｂ (This represents an oxygen atom, a sulfur atom, or a group represented by the following formula (E5).) 【Transformation 5】 (In the formula (E5), 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 (3) ａ or R in formula (3) ｃ They may be connected to each other to form a ring. (In formula (3), R ｃ This 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, the R ｃ R in formula (3) is ａ or the R in formula (E5) 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, the R １１ ~R ２０ Two or more of these are functional groups selected from the group consisting of a hydroxyl group, a hydroxyalkyl group having 1 to 3 carbon atoms, a carboxyl group, an amino group, and a thiol group, and the R ２１ ~R ２６ Two or more of these are functional groups selected from the group consisting of a hydroxyl group, a hydroxyalkyl group having 1 to 3 carbon atoms, a carboxyl group, an amino group, and a thiol group, and the R ３１ ~R ３４ Two or more of these are functional groups selected from the group consisting of a hydroxyl group, a hydroxyalkyl group having 1 to 3 carbon atoms, a carboxyl group, an amino group, and a thiol group, and the R ４１ ~R ４８ Two or more of these are functional groups selected from the group consisting of a hydroxyl group, a hydroxyalkyl group having 1 to 3 carbon atoms, a carboxyl group, an amino group, and a thiol group.

13. A composition containing an electron-transporting compound, The ASA of the electron-transporting compound, calculated using the following formulas (1) and (2), is 255 Å. ２ The above is true, and the electron transport compound has two or more hydrogen bond donor functional groups. A composition characterized by the following features. [Math 5] [Math 6] (In formula (1) and formula (2), R ｉ represents the van der Waals radius of atom i, R ｊ represents the van der Waals radius of atom j. d ｉｊ is the distance between atom i and atom j, and d ｉｊ =min(max(|R ｉ -R ｊ |, b ｉｊ ), R ｉ +R ｊ )).)

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