Photoelectric conversion element, photoelectric conversion device having the photoelectric conversion element

Abstract

To provide a photoelectric conversion element with excellent photoelectric conversion efficiency. [Solution] A photoelectric conversion element comprising a first electrode 3, a second electrode 7, a photoelectric conversion layer 5 disposed between the first electrode 3 and the second electrode 7, and a reflective layer 6 disposed between one of the first electrode 3 and the second electrode 7 and the photoelectric conversion layer 5, wherein the wavelength at which the reflectance of the reflective layer 6 is maximized in the visible light region is within the wavelength range where the optical absorption coefficient of the photoelectric conversion layer 5 is 1 / 5 or more of the maximum value in the visible light region.

Description

[Technical Field]

[0001] The present invention relates to a photoelectric conversion element and a photoelectric conversion device having the photoelectric conversion element. [Background technology]

[0002] In order to address the depletion of fossil fuels and the environmental problems caused by their use, research into renewable and clean alternative energy sources such as solar, wind, and hydroelectric power is actively being conducted. Among these, interest in solar cells, which directly convert sunlight into electrical energy, is growing significantly. Here, a solar cell refers to a battery that absorbs light energy from sunlight and generates current and voltage using the photovoltaic effect, which generates electrons and holes. Currently, np diode type silicon (Si) single crystal-based solar cells with a light energy conversion efficiency exceeding 20% ​​are widely known and are actually used in photovoltaic power generation. Furthermore, perovskite solar cells, which use compounds with a perovskite structure in the active layer, are attracting attention due to their high power generation efficiency and low cost, and are being extensively studied. In addition, by adjusting the halogen ratio in the active layer, the color of the active layer can be changed, and applications in brightly colored and aesthetically pleasing solar cells are anticipated. Non-patent document 1 describes a solar cell using an organic hybrid perovskite compound. It states that colorful solar cells can be obtained by controlling the bandgap of the perovskite. Patent Document 1 describes a photoelectric conversion element using TiO2, SnO, and ZnO as electron transport materials. Patent Document 2 describes a photoelectric conversion element using a perovskite compound as the material for the active layer, in which N-alkylperylenetetracarboxylic acid diimide is used as the electron transport compound for the electron transport layer. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Special Publication No. 2015-535390 [Patent Document 2] Japanese Patent Publication No. 2019-106401 [Non-patent literature]

[0004] [Non-Patent Document 1] Jun Hong Noh et al. Chemical Management for Colorful,Efficient, and Stable Inorganic-Organic Hybrid Nanostructured Solar Cells Nano Letter.2013,13,4,1764-1769 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] The solar cells described in Non-Patent Document 1, and Patent Documents 1 and 2 still had room for further improvement in photoelectric conversion efficiency. This invention has been made in view of the above-mentioned problems, and aims to provide a photoelectric conversion element with excellent photoelectric conversion efficiency. [Means for solving the problem]

[0006] The photoelectric conversion element of the present invention has a first layer containing a perovskite compound between the anode and the cathode, and a second layer between the cathode and the first layer. The second layer is characterized by having at least one of the structures represented by the following formula (U1) and the following formula (U2).

[0007] [ka] (In formulas (U1) to (U2), R 1 and R 3Each independently represents an alkylene group having 1 to 10 carbon atoms in the main chain, which may be substituted or unsubstituted, or a phenylene group which may be substituted or unsubstituted. R 2 represents a single bond, an alkylene group having 1 to 10 carbon atoms in the main chain, which may be substituted or unsubstituted, or a phenylene group which may be substituted or unsubstituted. The substituent of the substituted alkylene group is an alkyl group, an aryl group, a hydroxy group, or a halogen atom. The substituent of the substituted phenylene group is a halogen atom, a nitro group, a cyano group, a hydroxy group, an alkyl group, or a halogen-substituted alkyl group. R 9 represents a hydrogen atom or an alkyl group. A 1 represents any group represented by the following formulas (A-1) to (A-6). B 1 represents a group represented by any of the following formulas (B-1) to (B-3). D 1 is a group having 5 to 15 carbon atoms in the main chain represented by the following formula (D). E 1 is a group represented by any of the following formulas (E-1) to (E-3).)

[0008]

Chemical formula

[0009]

Chemical formula

[0010] [ka] (In formula (D), R 4 , R 5 , R 6 and R7 These independently represent an alkylene group with 1 to 5 atoms in the main chain, an alkylene group with 1 to 5 atoms in the main chain substituted with an alkyl group having 1 to 5 carbon atoms, an alkylene group with 1 to 5 atoms in the main chain substituted with a benzyl group, an alkylene group with 1 to 5 atoms in the main chain substituted with an alkylocarbonyl group, or an alkylene group with 1 to 5 atoms in the main chain substituted with a phenyl group. One of the carbon atoms in the main chain of the alkylene group is O, S, NH, or NR. 15 (R 15 (is an alkyl group.) It may be replaced by ( ). Ar 1 and Ar 2 Each of these independently represents a substituted or unsubstituted phenylene group. The substituents of the substituted phenylene group are a halogen atom, a nitro group, a hydroxyl group, a cyano group, an alkyl group, or an alkyl halide. A 2 This represents a group represented by any of the above formulas (A-1) to (A-6). l, m, n, o, p, and q are each independently either 0 or 1, and the sum of l, m, and n, and the sum of o, p, and q are between 1 and 3 (inclusive).

[0011] [ka] (In formulas (E-1) to (E-3), R 101 ~R 106 , R 201 ~R 210 , R 301 ~R 304 Each of these independently represents a single bond, a hydrogen atom, a cyano group, a nitro group, a halogen atom, an alkoxycarbonyl group, a carboxyl group, a dialkylamino group, a hydroxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group. 101 ~R 106 One of them, R 201 ~R 210 One of them, R 301 ~R 304One of these exhibits a single bond. Substituents for the substituted alkyl group include alkyl groups, aryl groups, halogen atoms, and carbonyl groups. Substituents for the substituted aryl group or substituted heterocyclic group include halogen atoms, nitro groups, cyano groups, alkyl groups, halogen-substituted alkyl groups, alkoxy groups, and carbonyl groups. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a photoelectric conversion element with excellent photoelectric conversion efficiency. [Brief explanation of the drawing]

[0013] [Figure 1] This is an example of a photoelectric conversion element according to an embodiment of the present invention. [Figure 2] This is an example of color measurement according to one embodiment of the present invention. [Figure 3] This is a schematic cross-sectional view in the thickness direction, illustrating the configuration of an example of a photoelectric conversion element according to one embodiment of the present invention. [Figure 4] This is a schematic diagram showing an example of the configuration of a photoelectric conversion element related to one embodiment of the present invention. [Figure 5] This is an example of a mobile body equipped with a photoelectric conversion element according to an embodiment of the present invention. [Figure 6] This is an example of a building material equipped with a photoelectric conversion element according to one embodiment of the present invention. [Figure 7] This figure shows the spectrum of Example 1-1. [Modes for carrying out the invention]

[0014] Photoelectric conversion element <First Embodiment (Reference Form)> The first embodiment of the present invention will now be described in detail. The photoelectric conversion element according to this embodiment comprises a first electrode, a second electrode, a photoelectric conversion layer disposed between the first electrode and the second electrode, and a reflective layer disposed between the first electrode and the second electrode and the photoelectric conversion layer, characterized in that the wavelength at which the reflectance of the reflective layer is maximized in the visible light region is within the wavelength range where the optical absorption coefficient of the photoelectric conversion layer is 1 / 5 or more of the maximum value in the visible light region. As a result of the inventors' investigations, it was found that having these configurations results in a photoelectric conversion element with excellent photoelectric conversion efficiency. In this embodiment, the "photoelectric conversion layer" may be referred to as the "functional layer" or "active layer." The photoelectric conversion layer may have a charge transport layer.

[0015] The reflective layer preferably has particles with a volume-average particle size of 50 nm to 600 nm. In this case, blue light can be reflected more strongly than other types of light. As a result, the amount of light absorbed by the functional layer increases, which can improve the photoelectric conversion efficiency.

[0016] The reflective layer strongly reflects blue light, which means the functional layer appears red. More specifically, the light reflected by the reflective layer and transmitted through the photoelectric conversion layer is L * c * h * Color space is 20 ≤ L * ,30≦c * ,0≦h * It can be said that ≤90. The color space is 47 ≤ c * It is acceptable for 20 ≤ L * , 42≦c * , 0≦h * It is acceptable for ≤50 and 20 ≤ L * , 47≦c * , 50≦h * It is acceptable for the value to be ≤90.

[0017] In this embodiment, the functional layer may have a layer that absorbs light and performs charge separation, that is, it may be a photoelectric conversion layer. Preferably, the reflective layer of the functional layer has light absorption at wavelengths where its reflectivity is higher than that of other wavelengths. Furthermore, the constituent material of the functional layer may be an organic material, an inorganic material, or a material containing perovskite. It may also be a mixed layer of these materials.

[0018] The reflective layer according to this embodiment is a layer with high reflectivity at wavelengths of light with high absorption in the functional layer. More specifically, the particle size of the particles in the reflective layer is 50 nm to 600 nm. Preferably, it is 70 nm to 500 nm, and more preferably, 90 nm to 400 nm. The particle size of the particles in the reflective layer may be measured by volume-average particle size.

[0019] The photoelectric conversion element according to this embodiment includes a first electrode, a second electrode, a photoelectric conversion layer disposed between them, and a reflective layer. The wavelength at which the reflectance of the reflective layer is maximized in the visible light region is within the range of wavelengths of light absorbed by the photoelectric conversion layer. More preferably, the wavelength at which the reflectance is maximized is within the range of wavelengths where the optical absorption coefficient of the photoelectric conversion layer is 1 / 5 or more of the maximum value in the visible light region, and even more preferably, the wavelength at which the reflectance is maximized is within the range of wavelengths where the optical absorption coefficient of the photoelectric conversion layer is half or more of the maximum value in the visible light region.

[0020] In the reflectance spectrum of the reflective layer against wavelength, the wavelength corresponding to the maximum reflectance can also be said to be within the range of wavelengths of light absorbed by the photoelectric conversion layer. Alternatively, the maximum peak of the spectrum can be said to be within the above range. When considering this spectrum, it may be in the visible light region, or the visible light region, the ultraviolet region, and the near-infrared region. More specifically, it may be between 250 nm and 1100 nm.

[0021] This embodiment will be described below with reference to the drawings.

[0022] Figure 1 is a schematic diagram showing an example of the configuration of a photoelectric conversion element 1 according to this embodiment. The substrate 2 has a first electrode 3, a charge transport layer 4, a photoelectric conversion layer 5, a reflective layer 6, and a second electrode 7. The first electrode 3 and the second electrode 7 may be anodes or cathodes. Current is generated in a configuration in which the first electrode 3 and the second electrode 7 are connected by an external circuit. The first electrode 3 and the second electrode 7 may be placed in swapped positions.

[0023] As an example, the photoelectric conversion layer 5 is excited by light incident through the substrate 2, the first electrode 3, and the charge transport layer 4, generating electrons or holes. That is, the photoelectric conversion layer 5 generates an electric current between the first electrode 3 and the second electrode 7. The charge transport layer 4 is a layer placed between the photoelectric conversion layer 5 and the two electrodes, and may not be formed in some cases. Multiple charge transport layers 4 and photoelectric conversion layers 5 may be stacked. Such a configuration can also be called a tandem structure.

[0024] A method for manufacturing the photoelectric conversion element according to this embodiment involves preparing coating solutions for each layer, which will be described later, applying them in the desired layer order, and then drying them. Examples of coating methods for the coating solution include immersion coating, spray coating, inkjet coating, roll coating, die coating, blade coating, curtain coating, wire bar coating, ring coating, and spin coater coating.

[0025] [Support substrate] Preferably, the support substrate is made of a material that allows electrodes (anode or cathode) to be formed on its main surface and does not undergo chemical changes when forming the functional layer constituting the photoelectric conversion element. The support substrate is also simply called a substrate.

[0026] Examples of materials for the support substrate include glass, plastic, polymer film, and silicon.

[0027] In the case of a photoelectric conversion element that takes in light from the support substrate side, a substrate with high light transmittance is preferably used for the support substrate.

[0028] Furthermore, when a photoelectric conversion element is mounted on an opaque support substrate, light cannot be captured through the support substrate. For this reason, it is preferable that the electrode furthest from the support substrate be transparent or semi-transparent. By making the electrode furthest from the support substrate transparent or semi-transparent, light can be captured through the electrode furthest from the support substrate when an opaque support substrate is used.

[0029] [electrode] The electrodes are formed from conductive materials. Examples of electrode materials include inorganic compounds such as metals and metal oxides, and organic compounds such as conductive polymers.

[0030] The electrode may be in the form of a single layer or in the form of multiple layers stacked together.

[0031] The first electrode and the second electrode may have one as the anode and the other as the cathode. Preferably, at least one of the anode and cathode is transparent or translucent.

[0032] The first and second electrodes receive the charge generated in the functional layer, and this charge is then extracted to the outside as electrical energy.

[0033] Examples of materials for transparent or translucent electrodes include conductive metal oxides and metals. If these materials are not transparent, they can be made into transparent or translucent electrodes by forming a thin film with a thickness sufficient to allow light to pass through. Specific examples of transparent or translucent electrode materials include, for example, indium oxide, zinc oxide, tin oxide, and their composites ITO, IZO, FTO, NESA, gold, platinum, silver, copper, and aluminum.

[0034] There are no particular restrictions on the method of forming electrodes (anode and cathode). For example, electrodes can be formed on the layer or support substrate by methods such as vacuum deposition, sputtering, ion plating, plating, or coating.

[0035] [Functional Layer] The functional layer is a layer located between the first electrode and the second electrode. The functional layer may have a photoelectric conversion layer that converts absorbed light into electric charge. The photoelectric conversion layer can also be called the active layer. The functional layer may have a charge transport layer. Depending on its form, the charge transport layer is called a hole transport layer or an electron transport layer.

[0036] The functional layer may be in contact with both or either of the first and second electrodes.

[0037] [Hole transport layer] In this embodiment, the photoelectric conversion element preferably has a hole transport layer provided between the photoelectric conversion layer and the anode.

[0038] The hole transport layer has the function of transporting holes from the photoelectric conversion layer to the anode. It also plays a role in reducing the transport of electrons from the photoelectric conversion layer to the anode, thereby reducing the decrease in photoelectric conversion efficiency due to electron and hole recombination. The hole transport layer is preferably provided in contact with the anode.

[0039] The hole transport material forming the hole transport layer is not particularly limited, but examples include inorganic materials such as CuI and CuNCS, and organic hole transport materials described in paragraphs 0209 to 0212 of Japanese Patent Application Publication No. 2001-291534. Preferred organic hole transport materials include conductive polymers such as polythiophene, polyaniline, polypyrrole and polysilane, spiro compounds in which two rings share a central atom with a tetrahedral structure such as C and Si, aromatic amine compounds such as triarylamines, triphenylene compounds, nitrogen-containing heterocyclic compounds or liquid crystalline cyano compounds.

[0040] The hole transport material is preferably an organic hole transport material that can be coated in solution and becomes solid. Specifically, examples include 2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9-spirobifluorene (also known as Spiro-OMeTAD), poly(3-hexylthiophene-2,5-diyl), 4-(diethylamino)benzoaldehyde diphenylhydrazone, polyethylenedioxythiophene (PEDOT), and the like.

[0041] The thickness of the hole transport layer is not particularly limited, but is preferably 50 μm or less, more preferably 1 nm to 10 μm, even more preferably 5 nm to 5 μm, and particularly preferably 10 nm to 1 μm. This thickness can be measured by observing the cross-section of the photoelectric conversion element using a scanning electron microscope (SEM) or the like.

[0042] The hole transport layer can be formed by preparing a conductive layer coating solution containing the above-mentioned materials and solvents, forming this coating film, and drying it. Examples of solvents used in the coating solution include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0043] [Photoelectric conversion layer] The photoelectric conversion layer of the photoelectric conversion element according to this embodiment may have a compound having a perovskite-type structure (perovskite compound).

[0044] The perovskite compound preferably has an organic-inorganic hybrid structure in which organic and inorganic compounds are components of the perovskite-type structure.

[0045] The organic-inorganic perovskite compound is preferably a compound represented by the general formula RM-X3.

[0046] In the general formula RM-X3, the above R is an organic molecule, and C l N m H n It is preferable to represent it as (where l, m, and n are all positive integers).

[0047] Specifically, R above can refer to, for example, methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, trimethylamine, triethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, ethylmethylamine, methylpropylamine, butylmethylamine, methylpentylamine, hexylmethylamine, ethylpropylamine, ethylbutylamine, imidazole, azole, pyrrole, aziridine, azirine, azetidine, azeto, azole, imidazoline, carbazole and their ions (e.g., methylammonium (CH3NH3)) and phenethylammonium. Among these, methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine and their ions and phenethylammonium are preferred, and methylamine, ethylamine, propylamine and their ions are more preferred.

[0048] In the general formula RM-X3, M is a metal atom, and examples include lead, tin, zinc, titanium, antimony, bismuth, nickel, iron, cobalt, silver, copper, gallium, germanium, magnesium, calcium, indium, aluminum, manganese, chromium, molybdenum, europium, etc. These metal atoms may be used individually or in combination of two or more.

[0049] In the general formula RM-X3, X is a halogen atom or a chalcogen atom, such as chlorine, bromine, iodine, sulfur, or selenium. These halogen atoms or chalcogen atoms may be used alone or in combination of two or more. Among these, halogen atoms are preferred because the inclusion of a halogen in the structure makes the organic-inorganic perovskite compound soluble in organic solvents, enabling its application to inexpensive printing methods and the like. Furthermore, iodine is more preferred because it narrows the energy band gap of the organic-inorganic perovskite compound.

[0050] The above organic-inorganic perovskite compound preferably has a cubic crystal structure in which a metal atom M is positioned at the body center, organic molecules R are positioned at each vertex, and halogen atoms or chalcogen atoms X are positioned at the face centers. Although the details are not clear, it is presumed that having the above structure allows the orientation of the octahedra in the crystal lattice to change easily, thereby increasing the electron mobility in the organic-inorganic perovskite compound and improving the photoelectric conversion efficiency.

[0051] Organic-inorganic perovskite compounds are preferably crystalline semiconductors. Being crystalline increases electron mobility and improves photoelectric conversion efficiency. A crystalline semiconductor refers to a semiconductor in which scattering peaks can be detected by X-ray diffraction measurements or similar methods.

[0052] Furthermore, the thickness of the organic-inorganic perovskite compound portion may be between 5 nm and 5000 nm. If it is greater than 5 nm, the amount of light absorbed increases, further increasing the photoelectric conversion efficiency. If it is less than 5000 nm, the occurrence of regions with low charge separation efficiency can be reduced, leading to an improvement in photoelectric conversion efficiency.

[0053] A more preferred thickness for the perovskite compound portion is 10 nm to 1000 nm, and an even more preferred thickness is 20 nm to 500 nm.

[0054] The active layer can be formed by preparing a conductive layer coating solution containing the above-mentioned materials and solvents, forming a coating film, and drying it. Examples of solvents used in the coating solution include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. The coating solution may also be prepared by mixing two solutions with different compositions.

[0055] [Reflective layer] The photoelectric conversion element according to this embodiment has a reflective layer that reflects incident light. It is positioned between the functional layer and the first or second electrode.

[0056] The reflective layer is stacked in the following order: first electrode, charge transport layer, photoelectric conversion layer, reflective layer, and second electrode. By reflecting light that was not absorbed by the photoelectric conversion layer, it promotes further light absorption in the perovskite layer, thereby improving the overall light absorption efficiency of the device.

[0057] To ensure that the light reflected by the reflective layer is easily absorbed by the photoelectric conversion layer, the reflective layer contains particles with a volume-average particle size of 50 nm to 600 nm. The particle size of the particles in the reflective layer is more preferably 70 nm to 500 nm, and particularly preferably 90 nm to 400 nm.

[0058] The refractive index of the particles is preferably 1.3 to 3.0, more preferably 1.8 to 3.0, and even more preferably 2.3 to 3.0. The aspect ratio of the particles is preferably 1.0 to 4.0, more preferably 1.0 to 3.0, and even more preferably 1.0 to 2.0.

[0059] The material of the particles is not particularly limited, but examples of metal compounds include zinc oxide, aluminum oxide, indium oxide, silicon oxide, zirconium oxide, tin oxide, titanium oxide, magnesium oxide, antimony oxide, bismuth oxide, barium sulfate, strontium titanate, barium titanate, and potassium niobate. Examples of metals include aluminum, nickel, iron, nichrome, copper, zinc, and silver. Examples of resin particles include acrylic resin, fluororesin, polystyrene resin, polyethylene resin, and silicone resin.

[0060] The particles may have a coating layer made of a conductive material. Examples of conductive materials include metal oxides, metallic materials such as aluminum, palladium, iron, copper, and silver, and composite materials surface-treated by electrolytic treatment, spray coating, or mixed vibration. Among these, metal oxides are preferred, and more preferably metal oxides. The metal oxide is preferably one selected from tin oxide, zinc oxide, and titanium oxide. These metal oxides can be given an oxygen-deficient structure by appropriate reduction, or can be further improved by appropriate doping. When tin oxide is used, it is preferably doped with an element selected from niobium, tantalum, phosphorus, tungsten, and fluorine. When zinc oxide is used, it is preferably doped with an element selected from aluminum and gallium. When titanium oxide is used, it is preferably doped with an element selected from niobium and tantalum.

[0061] In this embodiment, the aspect ratio of the particles was determined using a scanning electron microscope as follows: The particles to be measured were observed using a Hitachi S-4800 scanning electron microscope, and the long axis diameter and short axis diameter of 100 individual particles were measured from the images obtained from the observation, and their arithmetic mean was calculated.

[0062] Furthermore, in this embodiment, the refractive index of particles is defined as the value measured using Cargill standard refractive solution manufactured by Cargill. The specific measurement method is as follows: Place the particles on a glass slide and drop the refractive solution onto them. Mix the particles and refractive solution well and irradiate from below with a sodium lamp. Observe the outline of the particles from above, and if the outline is not visible, the refractive index of the refractive solution and the particles are considered to be equal. In addition, for the formed resin film, the refractive index is defined as the value measured according to JIS K7142 Plastics - Method for determining refractive index.

[0063] Furthermore, the refractive index of the fabricated resin film shall be defined as the value obtained using an Abbe refractometer DR-A1 (product name, manufactured by Atago Corporation).

[0064] The reflective layer according to this embodiment may contain a binder material in addition to particles. Examples of binder materials include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenolic resin, and alkyd resin. By using a binder material, the reflective layer can be formed densely and uniformly, the interface between the reflective layer and the active layer is uniformly formed, and the electron transport capacity is improved. On the other hand, if the binder resin is included in excess, the electron transport capacity within the reflective layer may decrease.

[0065] The weight ratio of particles to resin (particles / resin) in the reflective layer is preferably 100 / 1 to 2 / 1, more preferably 95 / 1 to 4 / 1, and even more preferably 90 / 1 to 10 / 1.

[0066] The average thickness of the reflective layer is preferably 50 nm to 1000 nm, and more preferably 70 nm to 500 nm.

[0067] The reflective layer can be formed by preparing a coating solution for the reflective layer containing the materials and solvents described above, forming a coating film, and drying it. Examples of solvents used in the coating solution include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Dispersion methods for dispersing particles in the reflective layer coating solution include using a paint shaker, sand mill, ball mill, or liquid impact type high-speed disperser. The conductive layer coating solution prepared by dispersion may be filtered to remove impurities before use as a reflective layer coating solution.

[0068] In this embodiment, the color was measured as shown in Figure 2. Specifically, a coating film was formed on the aluminum sheet 21 in the order of a reflective layer 22 and a photoelectric conversion layer 23, and using a spectrophotometer 24, the spectral reflectance was measured from the light received at a 90-degree angle to the coating film surface, with the light irradiated at a 45-degree angle to the axis perpendicular to the coating film surface. * ,c * free and h *The following measurements were taken. A perovskite layer can be used for the photoelectric conversion layer, and an RM200QC (manufactured by X-Rite) spectrophotometer can be used.

[0069] <Second Embodiment (Reference Form)> As a result of their investigation, the present inventors found that in a photoelectric conversion element having an anode, a first layer containing a perovskite compound, a conductive second layer, and a cathode in that order, the photoelectric conversion efficiency is improved when the second layer has conductive particles formed by coating core material particles with a conductive material.

[0070] Although the detailed mechanism by which the second embodiment of the present invention achieves its effect is unknown, it is presumed to be as follows: By coating the core material particles with a conductive material, an interaction occurs between the conductive material and the core material particles, bringing the conduction band energy level of the conductive material and the conduction band energy level of the perovskite compound in the first layer closer together. Therefore, it is thought that electron injection from the first layer to the second layer is promoted, increasing the current density and improving the photoelectric conversion efficiency.

[0071] The second embodiment of the present invention will be described in detail below. However, the present invention is not limited to the following embodiments, and modifications and improvements made to the following embodiments, based on the ordinary knowledge of those skilled in the art, are also included in the scope of the present invention, without departing from the spirit of the invention.

[0072] Figure 3 schematically shows the configuration of one embodiment of the photoelectric conversion element of this embodiment. Figure 3 is a schematic cross-sectional view of the photoelectric conversion element in the thickness direction (stacking direction), in which an anode 102, a charge transport layer 103, a first layer 104, a second layer 105, and a cathode 106 are stacked on a substrate 101. Current is generated between the anode 102 and the cathode 106 through an external circuit. The first layer 104 is a photoelectric conversion layer that is excited by light taken in from the substrate 101 side or the cathode 106 side, generating electrons or holes and generating a current between the anode 102 and the cathode 106; it is a so-called active layer. The charge transport layer 103 exists between the first layer 104 and the two electrodes 102 and 106, but it is not necessarily an essential component material in the photoelectric conversion element. Furthermore, the first layer 104 can also be formed in a tandem structure consisting of multiple layers. Furthermore, although the anode 102 is placed on the substrate 101 side in the configuration shown in Figure 3, the cathode 106 may be placed on the substrate 101 side, and the second layer 105, the first layer 104, the charge transport layer 103, and the anode 102 may be stacked in sequence. Hereafter, the first layer 104 will be referred to as the active layer 104.

[0073] The photoelectric conversion element of this embodiment can be manufactured by preparing coating solutions for each layer, as described later, applying them in the desired layer order, and drying them. Examples of coating methods include immersion coating, spray coating, inkjet coating, roll coating, die coating, blade coating, curtain coating, wire bar coating, ring coating, and spin coater coating.

[0074] <substrate> Preferably, the substrate 101 is made of a material that does not chemically change when forming the functional layer constituting the photoelectric conversion element, and on which electrodes (anode 102 in the case of Figure 3) can be formed on its main surface. Examples of substrate materials include glass, plastic, polymer film, and silicon. Furthermore, if light is to be taken in from the substrate 101 side, a transparent material is used for the substrate 101.

[0075] <electrode> Electrodes 102 and 106 are formed from a conductive material. Examples of materials that can be used for electrodes 102 and 106 include inorganic compounds such as metals and metal oxides, and organic compounds such as conductive polymers. Electrodes 102 and 106 may be in the form of a single layer or in the form of multiple layers stacked together.

[0076] When light is taken in from the substrate 101 side, a highly transparent material is preferably used for the electrode on the substrate 101 side (anode 102 in Figure 3) so that the photoelectric conversion element can function effectively. Also, when light is taken in from the side opposite to the substrate 101 (cathode 106 in Figure 3), the electrode on the opposite side to the substrate 101 (cathode 106 in Figure 3) is formed from a highly transparent material.

[0077] Examples of transparent or translucent electrode materials include conductive metal oxides and metals. If these materials are not transparent, a transparent or translucent electrode can be made by forming a thin film with a thickness sufficient to allow light to pass through. Specific examples of transparent or translucent electrode materials include indium oxide, zinc oxide, tin oxide, and their composites ITO, IZO, FTO, NESA, gold, platinum, silver, copper, and aluminum.

[0078] There are no restrictions on the method of forming electrodes 102 and 106; for example, they can be formed by vacuum deposition, sputtering, ion plating, plating, coating, etc.

[0079] <Hole transport layer> In this embodiment, it is preferable that the charge transport layer 103 between the anode 102 and the active layer 104 has a hole transport layer.

[0080] The hole transport layer 103 has the function of transporting holes from the active layer 104 to the anode 102. It also prevents the inflow of electrons from the active layer 104 to the anode 102, thereby preventing a decrease in photoelectric conversion efficiency due to electron and hole recombination. The hole transport layer is preferably provided in contact with the anode.

[0081] Examples of hole transport materials that form the hole transport layer 103 include conductive polymers such as polythiophene, polyaniline, polypyrrole and polysilane; spiro compounds in which two rings share a central atom with a tetrahedral structure such as C and Si; aromatic amine compounds such as triarylamines; triphenylene compounds; nitrogen-containing heterocyclic compounds or liquid crystalline cyano compounds.

[0082] Specifically, examples include 2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9-spirobifluorene (also known as Spiro-OMeTAD), poly(3-hexylthiophene-2,5-diyl), 4-(diethylamino)benzoaldehyde diphenylhydrazone, polyethylenedioxythiophene (PEDOT), etc. In addition, additives such as lithium-bis(trifluoromethanesulfonyl)imide and tert-butylpyridine (TBP) may be added to the hole transport layer 103.

[0083] The thickness of the hole transport layer 103 is not particularly limited, but is preferably 1 μm or less, and more preferably 100 nm to 600 μm. This thickness can be measured by observing the cross-section of the photoelectric conversion element using a scanning electron microscope (SEM) or the like.

[0084] The hole transport layer 103 can be formed by preparing a coating solution containing the above-mentioned materials and solvents, forming a coating film thereon, and drying it. Examples of solvents used in the coating solution include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0085] <Active layer> The active layer contains a compound having a perovskite-type structure (perovskite compound). The perovskite compound is preferably an organic-inorganic perovskite compound having an organic-inorganic hybrid structure in which organic and inorganic compounds are components of the perovskite-type structure, and is particularly preferably a compound represented by the general formula RMX3.

[0086] In the general formula RMX3, R is an organic molecule, such as methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, and their ions. M is a metal atom, such as Cu, Ni, Mn, Fe, Co, Pd, Ge, Sn, Pb, and Eu. These metal atoms may be used individually or in combination of two or more. Furthermore, X is a halogen atom, such as chlorine, bromine, iodine, and fluorine. These halogen atoms may be used individually or in combination of two or more.

[0087] Organic-inorganic perovskite compounds are preferably crystalline semiconductors. The crystalline nature of the organic-inorganic perovskite compound increases electron mobility and improves photoelectric conversion efficiency. A crystalline semiconductor refers to a semiconductor in which scattering peaks can be detected by X-ray diffraction measurements or similar methods.

[0088] Furthermore, the thickness of the active layer 104 is not particularly limited, but is preferably 2 μm or less, and more preferably 200 nm to 1 μm.

[0089] The active layer 104 can be formed by preparing a coating solution containing a material that forms a perovskite compound through a chemical reaction and a solvent, forming a coating film thereon, and drying it. Examples of solvents used in the coating solution include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0090] <Conductive layer> In this embodiment, the conductive layer 105 provided between the active layer 104 and the cathode 106 is an electron transport layer and has conductive particles formed by coating core material particles with a conductive substance. The core material particles and the conductive substance forming the coating layer have different compositions or materials from each other.

[0091] In this embodiment, the conductive material that forms the coating layer for the conductive particles includes metal oxides, aluminum, palladium, iron, copper, and silver; composite materials surface-treated by electrolytic treatment, spray coating, or mixed shaking; carbon black; and carbon-based materials. Among these, carbon black and metal oxides are preferred, and metal oxides are even more preferred. The metal oxide is preferably one selected from tin oxide, zinc oxide, and titanium oxide.

[0092] Furthermore, the above metal oxides can contribute to further improvement of current density by providing an oxygen-deficient structure through appropriate reduction or by appropriate doping. When using tin oxide, it is preferable that it is doped with an element selected from niobium, tantalum, phosphorus, tungsten, and fluorine. When using zinc oxide, it is preferable that it is doped with an element selected from aluminum and gallium. When using titanium oxide, it is preferable that it is doped with an element selected from niobium and tantalum.

[0093] The amount of dopant element in the above metal oxide is preferably 0.5% by mass or more and 10.0% by mass or less in the coating layer. If the doping amount is less than 0.5% by mass, the effect of improving the current density may not be sufficiently obtained. If the doping amount is greater than 10.0% by mass, leakage may easily occur in the photoelectric conversion element. Furthermore, it is more preferable that the doping amount is 1.0% by mass or more and 7.0% by mass or less in the coating layer.

[0094] In this embodiment, the constituent materials of the core material particles of the conductive particles include metal compounds, metals, carbon black, and resins. Examples of metal compounds include zinc oxide, aluminum oxide, indium oxide, silicon oxide, zirconium oxide, tin oxide, titanium oxide, magnesium oxide, antimony oxide, bismuth oxide, barium sulfate, strontium titanate, barium titanate, and potassium niobate. Examples of metals include aluminum, nickel, iron, nichrome, copper, zinc, and silver. Examples of resins include acrylic resin, fluororesin, polystyrene resin, polyethylene resin, and silicone resin.

[0095] Core material particles can be of various shapes, such as spherical, polyhedral, ellipsoidal, flaky, or needle-shaped. Among these, spherical, polyhedral, or ellipsoidal core material particles are preferred from the viewpoint of electron injection at the interface between the active layer and the conductive layer. Furthermore, it is even more preferable that the core material particles are spherical or polyhedral, close to spherical.

[0096] In this embodiment, the aspect ratio, expressed as the ratio (a / b) of the average major axis diameter a to the average minor axis diameter b of the conductive particles, is preferably 3.0 or less. An aspect ratio of 3.0 or less is preferable because it improves the electron injection efficiency from the active layer to the conductive layer 105.

[0097] Furthermore, it is preferable that the average major axis diameter a and average minor axis diameter b of the conductive particles are both between 50 nm and 600 nm. If the average major axis diameter a and average minor axis diameter b are 50 nm or more, re-aggregation of the conductive particles becomes less likely after the coating solution for the conductive layer is prepared. Also, if the average major axis diameter a and average minor axis diameter b are 600 nm or less, the surface of the conductive layer 105 becomes less likely to become rough. If the surface of the conductive layer 105 becomes rough, leakage is more likely to occur. Moreover, in this embodiment, it is even more preferable that the average major axis diameter a and average minor axis diameter b of the conductive particles are between 50 nm and 400 nm.

[0098] In this embodiment, the average major axis diameter a and average minor axis diameter b of the conductive particles are measured using a scanning electron microscope. Specifically, the major axis diameter and minor axis diameter of 100 individual conductive particles were measured from images obtained by observing the conductive particles to be measured using a Hitachi S-4800 scanning electron microscope, and their arithmetic mean was calculated.

[0099] Furthermore, in this embodiment, the average major axis diameter and average minor axis diameter of the core material particles are preferably 1 to 50 times the average thickness of the coating layer, and more preferably 5 to 20 times.

[0100] The conductive layer according to this embodiment may be formed solely of the conductive particles, but may also contain a binder material in addition to the conductive particles. Examples of binder materials include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenolic resin, and alkyd resin. In this embodiment, it is preferable that the conductive layer 105 contains 20% by volume or more of the conductive particles. If the content of conductive particles is less than 20% by volume, the distance between conductive particles increases, and the current density tends to decrease. Therefore, when the conductive layer 105 is composed of conductive particles and a binder resin, the content of the binder resin in the conductive layer 105 is 80% by volume or less.

[0101] Furthermore, the average thickness of the conductive layer 105 is preferably 0.1 μm or more and 1.0 μm or less, and more preferably 0.1 μm or more and 0.5 μm or less.

[0102] The conductive layer 105 can be formed by preparing a coating solution for a conductive layer containing the conductive particles, a solvent, and optionally the binder resin, forming a coating film therein, and drying it. Examples of solvents used in the coating solution include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Methods for dispersing conductive particles in the coating solution for a conductive layer include using a paint shaker, sand mill, ball mill, or liquid impaction type high-speed disperser. The coating solution for a conductive layer prepared by dispersion may be filtered to remove unnecessary components.

[0103] <Third Embodiment> A third embodiment of the present invention will be described in detail below.

[0104] As a result of the inventors' investigations, they found that the photoelectric conversion efficiency is improved by having a first layer containing a perovskite compound between the anode and the cathode, and a second layer between the cathode and the first layer, wherein the second layer has the configuration of this embodiment.

[0105] Although the detailed mechanism by which this embodiment achieves its effect is unknown, it is presumed to work as follows: It is believed that the photoelectric conversion efficiency is improved by two effects when the second layer containing the electron-transporting compound has one of the configurations of this embodiment. First, it is thought that electron extraction by the electron-transporting compound is improved. It is believed that the photoelectric conversion efficiency is improved because electron transfer occurs rapidly when the energy levels of the perovskite compound and the electron-transporting compound are matched. Second, it is thought that the formation of the first layer, which is laminated with the second layer as a base layer, is promoted and the crystallinity of the first layer is improved. It is thought that when the second layer has the configuration of this embodiment, an interface is easily formed, and the wettability of the surface has a high affinity with the first layer, promoting crystal growth. It is believed that the photoelectric conversion efficiency is improved because the light absorption is improved by the improved crystallinity of the first layer, and the generated charge can move efficiently.

[0106] The photoelectric conversion element of this embodiment has a first layer containing a perovskite compound between the anode and the cathode, and a second layer between the cathode and the first layer.

[0107] Figure 4 is a schematic diagram showing an example of the configuration of a photoelectric conversion element according to this embodiment. Figure 4(A) is a plan view seen from the cathode side, Figure 4(B) is a cross-sectional view of Figure 4(A) along line a-a', and Figure 4(C) is a cross-sectional view of Figure 4(A) along line b-b'. In the photoelectric conversion element of Figure 4, an anode 211, a third layer 212, a first layer 213, a second layer 214, and a cathode 215 are stacked on a substrate 216 in this order, and an electric current is generated between the anode 211 and the cathode 215 through an external circuit. In this example, the first layer 213 is a photoelectric conversion layer that is excited by light incident through the substrate 216, the anode 211 and the third layer 212, or the cathode 215 and the second layer 214, generating electrons or holes, and generating an electric current between the anode 211 and the cathode 215. The third layer 212 is a layer located between the first layer 213 and the anode 211, and is not necessarily an essential layer. The first layer 213 can have multiple layers and can also form a tandem structure.

[0108] One method for manufacturing the photoelectric conversion element of this embodiment is to prepare coating solutions for each layer, which will be described later, apply them in the desired order, and then dry them. Examples of coating methods for the coating solution include immersion coating, spray coating, inkjet coating, dispense coating, roll coating, die coating, blade coating, curtain coating, wire bar coating, ring coating, and spin coater coating.

[0109] <Substrate 216> Preferably, the substrate 216 is made of a material on which electrodes can be formed on its main surface and which does not undergo chemical changes when forming the functional layer constituting the photoelectric conversion element. Examples of materials for the support substrate include glass, plastic, polymer film, and silicon.

[0110] <Electrodes (anode 211, cathode 215)> The electrodes are formed from conductive materials. Examples of electrode materials include metals, inorganic compounds such as metal oxides, and organic compounds such as conductive polymers. The electrodes may be in the form of a single layer or a configuration of multiple layers stacked together.

[0111] In this embodiment, the photoelectric conversion element generates electrons and holes by absorbing light incident from the electrodes into a perovskite compound contained in the first layer 213. The generated electrons then reach the cathode 215 and the holes reach the anode 211, thereby extracting electrical energy (current) to the outside of the photoelectric conversion element. For the photoelectric conversion element to function effectively, the incident light needs to pass through the substrate 216 and reach the first layer 213; therefore, the substrate 216 and electrodes are preferably made of highly transparent materials. In the case of a photoelectric conversion element that takes in light from the substrate 216 side, the substrate 216 and the electrodes on the substrate 216 are preferably made of materials with high light transmittance. In the case of a photoelectric conversion element that takes in light from the electrode side furthest from the substrate 216, the electrode furthest from the substrate 216 is preferably made of a material with high light transmittance.

[0112] Examples of transparent or translucent electrode materials include conductive metal oxides and metals. If these materials are not transparent, they can be made into transparent or translucent electrodes by forming a thin film with a thickness sufficient to allow light to pass through. Specific examples of transparent or translucent electrode materials include indium oxide, zinc oxide, tin oxide, and their composites ITO, IZO, FTO, NESA, gold, platinum, silver, copper, and aluminum.

[0113] There are no restrictions on the method of forming the electrodes; for example, they can be formed by vacuum deposition, sputtering, ion plating, plating, coating, etc.

[0114] <Third Layer 212> The photoelectric conversion element according to this embodiment preferably has a third layer 212 provided between the first layer 213 and the anode 211. The third layer 212 may be a hole transport layer.

[0115] The third layer 212 has the function of transporting holes from the first layer 213 to the anode 211. It also prevents the inflow of electrons from the first layer 213 to the anode 211, thereby preventing a decrease in photoelectric conversion efficiency due to electron and hole recombination. Preferably, the third layer 212 is provided in contact with the anode 211.

[0116] Examples of hole transport materials forming the third layer 212 include conductive polymers such as polythiophene, polyaniline, polypyrrole, and polysilane; spiro compounds in which two rings share a central atom with a tetrahedral structure such as C and Si; aromatic amine compounds such as triarylamines; triphenylene compounds; nitrogen-containing heterocyclic compounds; or liquid crystalline cyano compounds. Specifically, examples include 2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9-spirobifluorene (also known as Spiro-OMeTAD), poly(3-hexylthiophene-2,5-diyl), 4-(diethylamino)benzoaldehyde diphenylhydrazone, polyethylenedioxythiophene (PEDOT), and others.

[0117] Additionally, additives such as lithium-bis(trifluoromethanesulfonyl)imide or t-butylpyridine (TBP) may be added to the third layer 212.

[0118] The thickness of the third layer 212 is not particularly limited, but is preferably 1 μm or less, and more preferably 200 nm to 60 μm. This thickness can be measured by observing the cross-section of the photoelectric conversion element using a scanning electron microscope (SEM) or the like.

[0119] The third layer 212 can be formed by preparing a conductive layer coating solution containing the above-mentioned materials and solvents, forming this coating film, and drying it. Examples of solvents used in the coating solution include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0120] <First layer 213> The first layer 213 contains a perovskite compound (a compound having a perovskite-type structure). The first layer 213 may be an active layer, a functional layer, or a photoelectric conversion layer.

[0121] The perovskite compound preferably has an organic-inorganic hybrid structure in which organic and inorganic compounds are components of the perovskite-type structure.

[0122] The organic-inorganic perovskite compound is preferably a compound represented by the general formula RMX3.

[0123] In the general formula RMX3, R is an organic molecule, such as methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, and their ions.

[0124] In the general formula RMX3, M is a metal atom, such as Cu, Ni, Mn, Fe, Co, Pd, Ge, Sn, Pb, or Eu. These metal atoms may be used individually or in combination of two or more.

[0125] In the general formula RMX3, X is a halogen atom, such as chlorine, bromine, iodine, or fluorine. These halogen atoms may be used individually or in combination of two or more.

[0126] Organic-inorganic perovskite compounds are preferably crystalline semiconductors. Being crystalline increases electron mobility and improves photoelectric conversion efficiency. A crystalline semiconductor refers to a semiconductor in which scattering peaks can be detected by X-ray diffraction measurements or similar methods.

[0127] Furthermore, the thickness of the organic-inorganic perovskite compound moiety is not particularly limited, but is preferably 2 μm or less, and more preferably 200 nm or more and 1 μm or less.

[0128] The first layer 213 can be formed by preparing a coating solution for a conductive layer containing the above-mentioned materials and solvents, forming this coating film, and drying it. Examples of solvents used in the coating solution include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. In particular, aprotic polar solvents such as dimethyl sulfoxide and dimethylformamide are preferred in terms of improving the solubility and crystallinity of each material in the first layer 213.

[0129] <Second Layer 214> The photoelectric conversion element according to this embodiment has a second layer 214 between the first layer 213 and the cathode 215. The second layer 214 may be an underlayer or a conductive layer.

[0130] [First photoelectric conversion element (reference element)] In the first photoelectric conversion element, the second layer 214 has a polymer compound, to which an electron transport compound is bonded.

[0131] Examples of electron-transporting compounds in the second layer 214 include oxadiazole derivatives, anthraquinodimethane and its derivatives, benzoquinone and its derivatives, naphthoquinone and its derivatives, anthraquinone and its derivatives, tetracyanoquinodimethane and its derivatives, fluorenone derivatives, diphenyldicyanoethylene and its derivatives, diphenoquinone derivatives, metal complexes of 8-hydroxyquinoline and its derivatives, polyquinoline and its derivatives, polyquinoxaline and its derivatives, polyfluorene and its derivatives, fullerenes and their derivatives, phenanthrene derivatives such as basocuproine, naphthalenetetracarboxylic acid diimide and its derivatives, perylenetetracarboxylic acid diimide and its derivatives, pyromellitic acid diimide and its derivatives, and the like. Among these, naphthalenetetracarboxylic acid diimide and its derivatives, perylenetetracarboxylic acid diimide and its derivatives, and pyromellitic acid diimide and its derivatives are preferred.

[0132] The second layer 214 may be a cured film obtained by curing a curable resin, and the electron transport compound may be bonded to the resin chains constituting the cured film.

[0133] [Second photoelectric conversion element (reference element)] In the second photoelectric conversion element, the second layer 214 has at least one structure represented by formulas (E-1) to (E-3) and at least one structure represented by formulas (P-1) to (P-5). The second layer 214 is a layer (cured layer) having at least one structure represented by formulas (E-1) to (E-3) and at least one structure represented by formulas (P-1) to (P-5). In other words, the second layer 214 contains a cured film (polymer) having at least one structure represented by formulas (E-1) to (E-3) and at least one structure represented by formulas (P-1) to (P-5).

[0134] [ka]

[0135] In formulas (E-1) to (E-3), R 101 ~R 106 , R 201 ~R 210 , R 301 ~R 304 Each of these independently represents a single bond, a hydrogen atom, a cyano group, a nitro group, a halogen atom, an alkoxycarbonyl group, a carboxyl group, a dialkylamino group, a hydroxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group. 101 ~R 106 One or two of R 201 ~R 210 One or two of R 301 ~R 304One or two of these represent a single bond. Substituents for substituted alkyl groups include alkyl groups, aryl groups, halogen atoms, and carbonyl groups. Substituents for substituted aryl groups or substituted heterocyclic groups include halogen atoms, nitro groups, cyano groups, alkyl groups, halogen-substituted alkyl groups, alkoxy groups, and carbonyl groups.

[0136] [ka]

[0137] In formulas (P-1) through (P-5), * indicates a binding site.

[0138] The single bond may be a single bond that bonds to the resin chain constituting the second layer 214, and the structures shown by formulas (P-1) to (P-5) may be part of the resin chain.

[0139] Tables 1 to 5 show specific examples of formulas (E-1) to (E-3). In Tables 1 to 5, the bonding points are indicated by dashed lines. Note that the specific examples shown in Tables 1 to 5 are the same as the specific examples indicated by the corresponding numbers in Tables 6 to 11 or Tables 12 to 19. 1 This shows the specific structure. Therefore, the same structure may be shown repeatedly in Tables 1 to 5.

[0140] [Table 1]

[0141] [Table 2]

[0142] [Table 3]

[0143] [Table 4]

[0144] [Table 5]

[0145] The second layer 214 can be formed, for example, as follows. First, a crosslinking agent, a resin having polymerizable functional groups that can react with the crosslinking agent, and an electron-transporting compound having polymerizable functional groups that can react with the crosslinking agent are dissolved in a solvent to prepare a coating solution. The second layer 214 can be obtained by forming a coating film of this coating solution and then heat-curing it. Heat curing is preferable because it allows for a more uniform reaction when the reaction occurs during the drying of the coating film.

[0146] [Electron transport compound] Preferred electron-transporting compounds include naphthyltetracarboxydiimide derivatives, perylenetetracarboxydiimide derivatives, and pyromellitic acid diimide derivatives. Furthermore, it is preferable that the electron-transporting compound has polymerizable functional groups that can react with the crosslinking agent. Examples of polymerizable functional groups include hydroxyl groups, thiol groups, carboxyl groups, amino groups, isocyanate groups, and acrylic groups.

[0147] Derivatives having the structure of (E-1) (derivatives of electron transport materials) can be synthesized, for example, using known synthesis methods described in U.S. Patent No. 4,442,193, U.S. Patent No. 4,992,349, U.S. Patent No. 5,468,583, and Chemistry of Materials, Vol. 19, No. 11, 2703-2705 (2007). They can also be synthesized by the reaction of naphthalenetetracarboxylic dianhydride, which can be purchased from Tokyo Chemical Industry Co., Ltd., Sigma-Aldrich Japan Ltd., and Johnson Matthey Japan, Incorporated, with monoamine derivatives.

[0148] Furthermore, in order to have polymerizable functional groups (e.g., hydroxyl groups, thiol groups, amino groups, and carboxyl groups) that can react with crosslinking agents, there are methods such as directly introducing polymerizable functional groups into a derivative having the structure of (E-1), or introducing a structure having a polymerizable functional group or a functional group that can serve as a precursor to a polymerizable functional group. The latter method includes, for example, introducing a functional group-containing aryl group using a cross-coupling reaction with a palladium catalyst and a base, starting with a halide of a naphthyltetracarboxydiimide derivative; introducing a functional group-containing alkyl group using a cross-coupling reaction with an FeCl3 catalyst and a base; and introducing a hydroxyalkyl group or carboxyl group by reacting with an epoxy compound or CO2 after lithiation. The former method includes, for example, using a naphthalenetetracarboxylic dianhydride derivative or monoamine derivative having a polymerizable functional group or a functional group that can serve as a precursor to a polymerizable functional group as a raw material when synthesizing naphthyltetracarboxydiimide derivatives.

[0149] Derivatives having the structure of (E-2) or (E-3) can be synthesized, for example, using known synthesis methods described in the Journal of the American Chemical Society, Vol. 129, No. 49, 15259-78 (2007). Alternatively, they can be synthesized by the reaction of a monoamine derivative with perylenetetracarboxylic dianhydride (E-2) or pyromellitic dianhydride (E-3), which are available from Tokyo Chemical Industry Co., Ltd., Sigma-Aldrich Japan Co., Ltd., or Johnson Matthey Japan, Inc.

[0150] Methods for introducing these polymerizable functional groups into derivatives having the (E-2) or (E-3) structure include directly introducing the polymerizable functional group and introducing a structure having a polymerizable functional group or a functional group that can serve as a precursor to a polymerizable functional group. The latter method includes, for example, a cross-coupling reaction using a palladium catalyst and a base, or a cross-coupling reaction using an FeCl3 catalyst and a base, based on a halide of a perylenetetracarboxydiimide derivative or pyromellitic acid diimide derivative. The former method includes, for example, using a perylenetetracarboxylic dianhydride derivative or monoamine derivative having a polymerizable functional group or a functional group that can serve as a precursor to a polymerizable functional group as a starting material when synthesizing a peryleneimide derivative.

[0151] Next, examples of electron-transporting compounds having polymerizable functional groups are listed below.

[0152] [ka]

[0153] [ka]

[0154] [ka]

[0155] [ka]

[0156] [ka]

[0157] [ka]

[0158] [ka]

[0159] [ka]

[0160] [ka]

[0161] [ka]

[0162] [The third photoelectric conversion element] In the third photoelectric conversion element, the second layer 214 has at least one of the structures represented by formula (U1) and formula (U2). The second layer 214 is a layer (cured layer) having at least one of the structures represented by formula (U1) and formula (U2). In other words, the second layer 214 contains a cured film (polymer) having at least one of the structures represented by formula (U1) and formula (U2).

[0163] [ka]

[0164] In formulas (U1) to (U2), R 1 and R 3 Each of these independently represents an alkylene group with 1 to 10 atoms in the substituted or unsubstituted main chain, or a substituted or unsubstituted phenylene group.

[0165] R 2represents a single bond, an alkylene group with 1 to 10 carbon atoms in the main chain, which may be substituted or unsubstituted, or a phenylene group which may be substituted or unsubstituted. The substituent of the substituted alkylene group is an alkyl group, an aryl group, a hydroxy group, or a halogen atom. The substituent of the substituted phenylene group is a halogen atom, a nitro group, a cyano group, a hydroxy group, an alkyl group, or a halogen-substituted alkyl group.

[0166] R 9 represents a hydrogen atom or an alkyl group.

[0167] A 1 represents any one of the groups represented by formulae (A-1) to (A-6).

[0168] B 1 represents a group represented by any one of formulae (B-1) to (B-3).

[0169] D 1 is a group with 5 to 15 carbon atoms in the main chain represented by formula (D). Further, from the viewpoint of improving the photoelectric conversion efficiency, more preferably, it is a group with 10 or more and 15 or less carbon atoms in the main chain represented by formula (D). Here, D 1 in, the number of carbon atoms in the main chain means the shortest number of atoms between the bonds at the right end and the left end of formula (D). For example, the p-phenylene group has 4 carbon atoms in the main chain. The m-phenylene group has 3 carbon atoms in the main chain. The o-phenylene group has 2 carbon atoms in the main chain.

[0170] E 1 is a group represented by any one of the following formulae (E-1) to (E-3).

[0171] Here, E in formulae (U1) and (U2) 1 on the right side represents a hydrogen atom, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkyl group, or a bonding site. One of the carbon atoms in the main chain of the substituted or unsubstituted alkyl group is O, S, NH, or NR 16 (R 16is an alkyl group.) may be replaced. Examples of the substituent of the substituted aryl group include an alkyl group, a halogen atom, a nitro group, or a cyano group. Examples of the substituent of the substituted alkyl group include an alkyl group, an aryl group, a halogen atom, a nitro group, or a cyano group. In the case of the bonding site, it is from the structures represented by the formulas (U1) and (U2) via a substituted or unsubstituted arylene group or a substituted or unsubstituted alkylene group to E 1 except for, D 1 is bonded to.

[0172]

Chemical formula

[0173] In formula (A-5), R 10 represents a hydrogen atom or an alkyl group.

[0174]

Chemical formula

[0175] In formulas (B-1) to (B-3), R 6 and R 7 each independently represent an alkylene group having 1 to 5 atoms in the main chain, an alkylene group having 1 to 5 atoms in the main chain substituted with an alkyl group having 1 to 5 carbon atoms, an alkylene group having 1 to 5 atoms in the main chain substituted with a benzyl group, an alkylene group having 1 to 5 atoms in the main chain substituted with an alkoxycarbonyl group, or an alkylene group having 1 to 5 atoms in the main chain substituted with a phenyl group. One of the carbon atoms in the main chain of the alkylene group may be replaced by O, S, NH or NR 15 (R 15 is an alkyl group.)

[0176] R 2represents a single bond, an alkylene group with 1 to 10 carbon atoms in the main chain which may be substituted or unsubstituted, or a phenylene group which may be substituted or unsubstituted. The substituent of the substituted alkylene group is an alkyl group, an aryl group, a hydroxy group, or a halogen atom. The substituent of the substituted phenylene group is a halogen atom, a nitro group, a cyano group, a hydroxy group, an alkyl group, or a halogen-substituted alkyl group.

[0177] R 12 represents a hydrogen atom or an alkyl group.

[0178] Ar 2 represents a phenylene group which may be substituted or unsubstituted. The substituent of the substituted phenylene group is a halogen atom, a nitro group, a hydroxy group, a cyano group, an alkyl group, or a halogenated alkyl group.

[0179] A 1 and A 2 represent any one of the groups represented by formulas (A-1) to (A-5).

[0180] E 1 is a group represented by any one of the following formulas (E-1) to (E-3).

[0181] o, p, and q are each independently 0 or 1, and the sum of o, p, and q is 1 or more and 3 or less.

[0182] The arrow indicates the side bonded to R 3 and points to the side.

[0183] The right side of E in (B-2) 1 is a hydrogen atom, a substituted or unsubstituted aryl group, an alkyl group, a heterocyclic group, or a bonding site. Examples of the substituent of the substituted aryl group include an alkyl group, a halogen atom, and a nitro group. In the case of the bonding site, a substituted or unsubstituted arylene group, or a structure represented by formulas (U1) and (U2) via an alkylene group, excluding E 1 from D 1This indicates that it is bonded to the side chain of the resin present in the second layer 214.

[0184] R in equation (B-2) 6 ,R 7 ,Ar 2 ,A 2 ,o,p,q are R in equation (D), respectively. 6 ,R 7 ,Ar 2 ,A 2 ,o,p,q may be the same or different. E in equation (B-2) 1 E is the E of equations (U1) and (U2). 1 It may be the same or different. R in equation (B-3) 2 ,A 1 These are the R values ​​of equation (U1) and equation (U2), respectively. 2 ,A 1 It can be the same or different.

[0185] [ka]

[0186] In formula (D), R 4 , R 5 , R 6 and R 7 These independently represent an alkylene group with 1 to 5 atoms in the main chain, an alkylene group with 1 to 5 atoms in the main chain substituted with an alkyl group having 1 to 5 carbon atoms, an alkylene group with 1 to 5 atoms in the main chain substituted with a benzyl group, an alkylene group with 1 to 5 atoms in the main chain substituted with an alkylocarbonyl group, or an alkylene group with 1 to 5 atoms in the main chain substituted with a phenyl group. One of the carbon atoms in the main chain of the alkylene group is O, S, NH, or NR. 15 (R 15 is an alkyl group. ) may be replaced by R. 4 , R 5 , R 6 and R 7It is more preferable that each is independently an alkylene group having 1 to 5 carbon atoms in the main chain, or an alkylene group having 1 to 5 carbon atoms in the main chain substituted with a methyl group or an ethyl group.

[0187] Ar 1 and Ar 2 each independently represents a substituted or unsubstituted phenylene group. The substituent of the substituted phenylene group is a halogen atom, a nitro group, a hydroxy group, a cyano group, an alkyl group, or a halogenated alkyl group. Ar 1 and Ar 2 are more preferably unsubstituted phenylene groups.

[0188] A 2 represents a group represented by any of formulas (A-1) to (A-6).

[0189] l, m, n, o, p, and q are each independently 0 or 1, and the sum of l, m, and n and the sum of o, p, and q are 1 or more and 3 or less.

[0190]

Chemical formula

[0191] In formulas (E-1) to (E-3), R 101 to R 106 , R 201 to R 210 , R 301 to R 304 each independently represents a single bond, a hydrogen atom, a cyano group, a nitro group, a halogen atom, an alkoxycarbonyl group, a carboxyl group, a dialkylamino group, a hydroxy group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group. One of R 101 to R 106 , one of R 201 to R 210 , one of R 301 to R 304One of them represents a single bond. Substituents for the substituted alkyl group include alkyl groups, aryl groups, halogen atoms, and carbonyl groups. Substituents for the substituted aryl group or the substituted heterocyclic group include halogen atoms, nitro groups, cyano groups, alkyl groups, halogen-substituted alkyl groups, alkoxy groups, and carbonyl groups.

[0192] In the structure shown by equation (U1), R in equation (U1) 2 It is bonded to structure X, which is enclosed by the dashed line in the following equation. Note that this structure X is considered to be the part corresponding to the resin chain. The same reasoning can be applied to equation (U2).

[0193] [ka]

[0194] The inventors believe that the second layer 214, having the structures shown by formulas (U1) and (U2), improves the photoelectric conversion efficiency through two effects. One is the electron transport compound (E 1 This is thought to be because the electron extraction effect is improved by the urethane bond. Not only electron transport compounds, but also urethane bonds have electron-withdrawing properties. Therefore, it is thought that the photoelectric conversion efficiency is improved because electron transfer from the perovskite compound occurs rapidly. Another reason is that the formation of the first layer 213, which is laminated with the second layer 214 as the base layer, is promoted, and the crystallinity of the first layer 213 is improved. It is thought that because the second layer 214 has this structure, an interface is easily formed, and the wettability of the surface has a high affinity with the first layer 213, promoting crystal growth. It is thought that the photoelectric conversion efficiency is improved because the light absorption is improved by the improved crystallinity of the first layer 213, and the generated charge can be moved efficiently.

[0195] The second layer 214 preferably contains the structures represented by formulas (U1) and (U2) in an amount of 30% to 100% by mass relative to the total mass of the second layer 214.

[0196] The content of structures represented by formulas (U1) and (U2) in the second layer 214 can be analyzed using general analytical methods. Examples of analytical methods are shown below. The content of structure represented by formula (U1) in the underlying layer is determined using FT-IR and the KBr-tab method. By creating a calibration curve based on absorption derived from the isocyanurate structure using samples with varying amounts of tris(2-hydroxyethyl) isocyanurate added to KBr powder, the content of structure represented by formula (U1) in the second layer 214 can be calculated. The same approach can be applied to formula (U2).

[0197] Furthermore, the structures shown by equations (U1) and (U2) are solid relative to the second layer 214. 13 This can be confirmed by measurement methods such as 13C-NMR measurement, mass spectrometry measurement, MS spectroscopy measurement by pyrolysis GC analysis, and characteristic absorption measurement by infrared spectroscopy. For example, solid 13 ¹ 13 Measurement can be performed under the following conditions: C, reference material polydimethylsiloxane, number of cumulative cycles 8192, pulse series CP / MAS, DD / MAS, pulse width 2.1 μsec (DD / MAS), 4.2 μsec (CP / MAS), contact time 2.0 msec, sample rotation speed 10 kHz. Mass spectrometry is performed using a mass spectrometer (MALDI-TOF MS: ultraflex, manufactured by Bruker Daltonics, Inc.) under the following conditions: acceleration voltage: 20 kV, mode: Reflector, molecular weight standard: fullerene C60. The molecular weight is measured and confirmed by the obtained peak top value.

[0198] In addition to the structures shown by formulas (U1) and (U2), the second layer 214 may also contain various resins, crosslinking agents, organic particles, inorganic particles, metal oxide particles, leveling agents, catalysts for curing acceleration, etc., in order to improve film formation and photoelectric conversion efficiency. However, the content of these is preferably less than 50% by mass, and more preferably less than 20% by mass, relative to the total mass of the second layer 214. Furthermore, the film thickness of the second layer 214 is preferably between 10 nm and 1.0 μm.

[0199] Specific examples of structures represented by formulas (U1) and (U2) are shown below, but the present invention is not limited to these. In Tables 6 to 11, bonding sites are indicated by dashed lines. Also, single bonds are indicated by "single". Furthermore, the left-right orientation of formulas (U1) and (U2) is the same as the left-right orientation of each structure in Tables 6 to 11. Also, in the example compounds in Tables 6 to 11, the R in formulas (U1) and (U2) 9 , R 12 These are all hydrogen atoms. R in equation (B-2) 6 ,R 7 ,Ar 2 ,A 2 ,o,p,q are D 1 Inside, R 6 ,R 7 ,Ar 2 ,A 2 This is the same as what was shown in o, p, q. E in equations (U1) and (U2) 1 Specific examples are shown in Tables 1 through 5, indicated by their corresponding numbers.

[0200] [Table 6]

[0201] [Table 7]

[0202] [Table 8]

[0203] [Table 9]

[0204] [Table 10]

[0205] [Table 11]

[0206] The second layer 214 can be formed, for example, as follows. First, an isocyanate compound (crosslinking agent), a resin having polymerizable functional groups that can react with the isocyanate groups of the isocyanate compound, and an electron-transporting compound having polymerizable functional groups that can react with the isocyanate groups of the isocyanate compound are dissolved in a solvent to prepare a coating solution. The second layer 214 can be obtained by forming a coating film of this coating solution and then heat-curing it. Heat curing is preferable because it allows for a more uniform reaction when the reaction occurs during the drying of the coating film.

[0207] [Isocyanate compounds] The isocyanate compound is preferably an isocyanate compound in which the isocyanate group is protected with a blocking agent such as an oxime (blocked isocyanate compound). When the blocked isocyanate compound is heated together with the resin and the electron transport compound, an addition reaction is initiated, the blocking agent is removed and the crosslinking reaction proceeds. A cured product having the structures shown in formulas (U1) and (U2) is then obtained.

[0208] Examples of blocking agents include active methylene compounds such as ethyl acetate and acetylacetone, mercaptan compounds such as butyl mercaptan and dodecyl mercaptan, acid amide compounds such as acetanilide and acetic acid amide, lactam compounds such as ε-caprolactam, δ-valerolactam, and γ-butyrolactam, acid imide compounds such as succinimide and maleimide, imidazole compounds such as imidazole and 2-methylimidazole, urea compounds such as urea, thiourea, and ethyleneurea, oxime compounds such as formamide oxime, acetaldehyde oxime, acetone oxime, methyl ethyl ketoxime, methyl isobutyl ketoxime, and cyclohexanone oxime, and amine compounds such as diphenylaniline, aniline, carbazole, ethyleneimine, and polyethyleneimine. These blocking agents can be used individually or in combination of two or more. Among these blocking agents, oxime compounds such as methyl ethyl ketoxime, lactam compounds such as ε-caprolactam, and imidazole compounds such as 2-methylimidazole are preferred from the viewpoint of versatility, ease of manufacture, workability, and thermosetting temperature.

[0209] Next, examples of isocyanate compounds are listed below.

[0210] [ka]

[0211] [ka]

[0212] The isocyanate groups (number of moles = I) of the isocyanate compound are preferably present in the isocyanate compound in a molar ratio (I / H) of 0.5 to 5.0 relative to the sum of the polymerizable functional groups of the resin and the polymerizable functional groups of the electron transport compound (number of moles = H). This molar ratio (I / H) of 0.5 to 5.0 is preferable because it improves the reaction efficiency between the isocyanate groups and the polymerizable functional groups, thereby increasing the crosslinking density.

[0213] [Electron transport compound] Details of electron-transporting compounds having polymerizable functional groups that can react with isocyanate groups are as described in the section on "Electron-Transporting Compounds" in the "Second Photoelectric Conversion Element" above.

[0214] 〔resin〕 The polymerizable functional groups of the resin are preferably hydroxyl groups, carboxyl groups, amide groups, and thiol groups. Furthermore, hydroxyl groups or amide groups are preferred because they have high reaction efficiency with isocyanate groups. In other words, the resin is preferably a polyol resin, polyvinylphenol resin, polyvinylphenol resin, or polyamide resin having two or more hydroxyl groups or amide groups. The molecular weight of the resin is preferably in the range of weight-average molecular weight (Mw) = 5,000 to 1,500,000.

[0215] The cured product having the structures shown in formulas (U1) and (U2) is preferably further having the structure shown in formula (2) below. In other words, it is preferable that the resin has the structure shown in formula (2) below. Having the structure shown in formula (2) results in good adhesion between the lower and upper layers of the second layer 214 and uniformity of the film thickness of the second layer 214, leading to an improvement in photoelectric conversion efficiency.

[0216] [ka]

[0217] In formula (2), R 8 This represents a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms. The substituents of a substituted alkyl group are an alkyl group, an aryl group, or a halogen atom.

[0218] 〔solvent〕 For preparing the coating solution for forming the second layer 214, any solvent can be arbitrarily selected from, for example, alcohol-based, aromatic-based, halogenated hydrocarbon-based, ketone-based, ketone alcohol-based, ether-based, ester-based, etc. More specifically, for example, organic solvents such as methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellsolve, ethyl cellsolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, and toluene can be used. These solvents can be used individually or in mixtures of two or more.

[0219] [Confirmation of curing properties] The curability of the second layer 214 can be confirmed, for example, as follows: A coating film of the coating solution for forming the second layer 214, containing an isocyanate compound, a resin, and an electron transport substance, is formed on an aluminum sheet using a Meyer bar. This coating film is then heated and dried at 160°C for 40 minutes to form the second layer 214. The obtained second layer 214 is immersed in a cyclohexanone / ethyl acetate = 1 / 1 mixed solvent for 2 minutes and dried at 160°C for 5 minutes. The mass of the second layer 214 is checked before and after immersion to confirm that there is no elution (mass difference within ±2%).

[0220] [Fourth photoelectric conversion element (reference element)] In the fourth photoelectric conversion element, the second layer 214 has at least one of the structures represented by formula (C1) and formula (C2). The second layer 214 is a layer (cured layer) having at least one of the structures represented by formula (C1) and formula (C2). In other words, the second layer 214 contains a cured film (polymer) having at least one of the structures represented by formula (C1) and formula (C2).

[0221] [ka]

[0222] In formulas (C1) and (C2), R 11 ~R 16 and R 22 ~R 25 These are, independently, a hydrogen atom, a methylene group, and a -CH2OR group. 2 (R 2 R represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. It represents a monovalent group represented by formula (i), or a group represented by formula (ii). 11 ~R 16 At least one of R 22 ~R 25 At least one of them is a group represented by formula (i), and R 11 ~R 16 At least one of R 22 ~R 25 At least one of them is a group represented by formula (ii).

[0223] R 21 This represents an alkyl group, a phenyl group, or an alkyl-substituted phenyl group.

[0224] [ka]

[0225] In formula (i), R 61 This represents a hydrogen atom or an alkyl group.

[0226] Y 1 This represents a single bond, an alkylene group, or a phenylene group.

[0227] F 1 This represents a divalent group represented by any of the formulas (F1) to (F4).

[0228] * indicates the side that joins to N in equation (C1) or to N in equation (C2).

[0229] [ka]

[0230] [ka]

[0231] In formula (ii), F 2 This represents a divalent group represented by any of the formulas (F1) to (F4).

[0232] α represents an alkylene group with 1 to 6 atoms in the main chain, an alkylene group with 1 to 6 atoms in the main chain substituted with an alkyl group having 1 to 6 carbon atoms, an alkylene group with 1 to 6 atoms in the main chain substituted with a benzyl group, an alkylene group with 1 to 6 atoms in the main chain substituted with an alkoxycarbonyl group, or an alkylene group with 1 to 6 atoms in the main chain substituted with a phenyl group. One of the carbon atoms in the main chain of the alkylene group is O, S, NH, or NR 1 (R 1 is an alkyl group having 1 to 6 carbon atoms. ) may be replaced by ). Preferably, α is an alkylene group having 1 to 5 atoms in the main chain, or an alkylene group having 1 to 5 atoms in the main chain that is substituted with an alkyl group having 1 to 4 carbon atoms.

[0233] β represents a phenylene group, a phenylene group substituted with an alkyl group having 1 to 6 carbon atoms, a nitro-substituted phenylene group, or a halogen-substituted phenylene group. β is preferably a phenylene group.

[0234] γ represents an alkylene group with 1 to 6 atoms in the main chain, or an alkylene group with 1 to 6 atoms in the main chain substituted with an alkyl group having 1 to 6 carbon atoms. Preferably, γ is an alkylene group with 1 to 5 atoms in the main chain, or an alkylene group with 1 to 5 atoms in the main chain substituted with an alkyl group having 1 to 4 carbon atoms.

[0235] r, s, and t are each either 0 or 1.

[0236] E 1 This is a divalent group represented by any of the formulas (E-1) to (E-3).

[0237] * indicates the side that joins to N in equation (C1) or to N in equation (C2).

[0238] E in equation (ii) 1 When the number of atoms in the main chain other than is 12 or less, the distance between the triazine ring and the electron transport site is appropriate, which is preferable because smooth electron transport is exhibited through interaction and the photoelectric conversion efficiency is improved. More preferably, E in formula (ii) 1 The number of atoms in the other main chains is between 2 and 9.

[0239] [ka]

[0240] In formulas (E-1) to (E-3), R 101 ~R 106 , R 201 ~R 210 , R 301 ~R 304 Each of these independently represents a single bond, a hydrogen atom, a cyano group, a nitro group, a halogen atom, an alkoxycarbonyl group, a carboxyl group, a dialkylamino group, a hydroxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group. 101 ~R 106 One or two of R 201 ~R 210 One or two of R 301 ~R 304 One or two of these represent a single bond. Substituents for substituted alkyl groups include alkyl groups, aryl groups, halogen atoms, and carbonyl groups. Substituents for substituted aryl groups or substituted heterocyclic groups include halogen atoms, nitro groups, cyano groups, alkyl groups, halogen-substituted alkyl groups, alkoxy groups, and carbonyl groups.

[0241] The structure represented by formula (C1) has a moiety derived from a melamine compound, and the structure represented by formula (C2) has a moiety derived from a guanamine compound. The moiety derived from the melamine compound or the moiety derived from the guanamine compound is bonded to the group represented by formula (i) and the group represented by formula (ii). The group represented by formula (i) is a resin-derived moiety. The group represented by formula (ii) has an electron-transporting moiety represented by any of (E-1) to (E-3).

[0242] The inventors believe that the second layer 214, having the structures shown by formulas (C1) and (C2), improves the photoelectric conversion efficiency through two effects. One is the electron transport compound (E 1 This is thought to be because the electron extraction effect is improved by bonding with the structures shown in formulas (C1) and (C2). Melamine compounds and guanamine compounds have a triazine ring structure, and as a property of the triazine ring, they have electron deficiency. It is thought that the coexistence of electron transport compounds and triazine rings allows for rapid electron transfer from the perovskite compound, improving the photoelectric conversion efficiency. Another reason is that the formation of the first layer 213, which is laminated with the second layer 214 as a base layer, is promoted, and the crystallinity of the first layer 213 is improved. It is thought that the second layer 214 adopting this structure makes it easier to form an interface, and the wettability of the surface has a high affinity with the first layer 213, promoting crystal growth. It is thought that the improved crystallinity of the first layer 213 improves light absorption, and the generated charge can move efficiently, thus improving the photoelectric conversion efficiency.

[0243] The structures represented by formula (C1) and formula (C2) are bonded to at least one of the groups represented by formula (i) and formula (ii). If the remaining group not bonded to the group represented by formula (i) or formula (ii) is a methylene group, it may be bonded to the melamine structure or the guanamine structure via the methylene group.

[0244] [ka]

[0245] The second layer 214 preferably contains the structure represented by formula (C1) and the structure represented by formula (C2) in an amount of 30% to 100% by mass relative to the total mass of the second layer 214.

[0246] The content of the structure represented by formula (C1) or (C2) in the second layer 214 can be analyzed using general analytical methods. Examples of analytical methods are shown below. The content of the structure represented by formula (C1) or (C2) is determined using FT-IR and the KBr-tab method. By creating a calibration curve based on absorption derived from the triazine ring using samples in which the amount of melamine or guanamine added to KBr powder is varied, the content of the structure represented by formula (C1) or (C2) in the second layer 214 can be calculated.

[0247] Furthermore, the structure represented by formula (C1) or (C2) is solid relative to the second layer 214. 13 This can be confirmed by measurement methods such as 13C-NMR measurement, mass spectrometry measurement, MS spectroscopy measurement by pyrolysis GC analysis, and characteristic absorption measurement by infrared spectroscopy. For example, solid 13 ¹ 13 Measurement can be performed under the following conditions: C, reference material polydimethylsiloxane, 8192 cumulative cycles, pulse series CP / MAS, DD / MAS, pulse width 2.1 μsec (DD / MAS), 4.2 μsec (CP / MAS), contact time 2.0 msec, and sample rotation speed 10 kHz. Mass spectrometry is performed using a mass spectrometer (MALDI-TOF MS: ultraflex, manufactured by Bruker Daltonics, Inc.) under the following conditions: acceleration voltage: 20 kV, mode: Reflector, molecular weight standard: fullerene C60. The molecular weight is measured and confirmed by the obtained peak top value.

[0248] In addition to the structure represented by formula (C1) or (C2), the second layer 214 may contain various resins, crosslinking agents, organic particles, inorganic particles, metal oxide particles, leveling agents, catalysts for curing acceleration, etc., in order to improve film formation and photoelectric conversion efficiency. However, the content of these is preferably less than 50% by mass and more preferably less than 20% by mass of the total mass of the second layer 214. Furthermore, the film thickness of the second layer 214 is preferably between 10 nm and 1.0 μm.

[0249] The following are specific examples of structures represented by formula (C1) or (C2), but the present invention is not limited to these. Furthermore, in each specific example, in formula (ii), the electron transport site is E 1 The number of atoms in the main chain other than those shown is indicated. In Tables 12 to 19, bonding sites are indicated by dashed lines. Single bonds are indicated by "single". Also, the left-right orientation of the group shown in formula (i) and the group shown in formula (ii) is the same as the left-right orientation of each structure in Tables 12 to 19. E in formula (ii) 1 Specific examples are shown in Tables 1 through 5, indicated by their corresponding numbers.

[0250] [Table 12]

[0251] [Table 13]

[0252] [Table 14]

[0253] [Table 15]

[0254] [Table 16]

[0255] [Table 17]

[0256] [Table 18]

[0257] [Table 19]

[0258] The second layer 214 can be formed, for example, as follows: First, a coating solution containing a melamine compound or a guanamine compound, a resin having polymerizable functional groups that can react with these compounds, and an electron-transporting compound having polymerizable functional groups that can react with these compounds is applied to form a coating film. Then, the second layer 214 can be obtained by thermal curing the resulting coating film.

[0259] [Melamine compounds, guanamine compounds] Melamine compounds and guanamine compounds will be described. Melamine compounds or guanamine compounds are synthesized, for example, using melamine or guanamine and formaldehyde by known methods.

[0260] Specific examples of melamine compounds and guanamine compounds are shown below. While the following examples show monomers, they may also contain monomer oligomers (polymers). From the viewpoint of improving conversion efficiency, it is preferable that the monomers be present in an amount of 10% by mass or more relative to the total mass of the monomers and polymers combined. The degree of polymerization of the polymer is preferably between 2 and 100. Furthermore, two or more types of polymers and monomers can be used in mixture form. Examples of commonly available melamine compounds include Super Melami No. 90 (manufactured by Nippon Oil & Fats Co., Ltd.), Super Beccamine(R) TD-139-60, L-105-60, L127-60, L110-60, J-820-60, G-821-60 (manufactured by DIC Corporation), Yuban 2020 (Mitsui Chemicals), Sumitex Resin M-3 (Sumitomo Chemical Industries), Nikalac MW-30, MW-390, MX-750LM (manufactured by Nippon Carbide Co., Ltd.). Examples of commonly available guanamine compounds include Super Beccamine(R) L-148-55, 13-535, L-145-60, TD-126 (manufactured by DIC Corporation), Nikalac BL-60, BX-4000 (manufactured by Nippon Carbide Co., Ltd.).

[0261] The following are specific examples of melamine compounds.

[0262] [ka]

[0263] [ka]

[0264] The following are specific examples of guanamine compounds.

[0265] [ka]

[0266] [ka]

[0267] [ka]

[0268] The molar ratio (I:H) of the functional groups (number of moles = I) of the melamine compound and guanamine compound to the total number of polymerizable functional groups (number of moles = H) of the resin and electron transport compound (compounds having a structure represented by any of (E-1) to (E-3)) is preferably 1:0.5 to 1:3.0. This molar ratio is preferable because it increases the proportion of reactive functional groups.

[0269] [Electron transport compound] Details of the electron-transporting compound having polymerizable functional groups that can react with melamine compounds or guanamine compounds are as described in the section on [Electron-Transporting Compounds] in the [Second Photoelectric Element] above. The electron-transporting compound is E in formula (ii). 1 It originates from the structure shown.

[0270] 〔resin〕 This section describes a resin having polymerizable functional groups that can react with melamine compounds or guanamine compounds. The resin has the group shown in formula (i). This resin can be obtained by polymerizing monomers having polymerizable functional groups (hydroxyl group, thiol group, amino group, carboxyl group, and methoxy group), which can be purchased, for example, from Sigma-Aldrich Japan Co., Ltd. or Tokyo Chemical Industry Co., Ltd.

[0271] Furthermore, these resins are generally available for purchase. Examples of commercially available resins include polyether polyol resins such as AQD-457 and AQD-473 from Nippon Polyurethane Industries, Ltd., and Sannix GP-400 and GP-700 from Sanyo Chemical Industries, Ltd., as well as polyester polyols such as Phthalkid W2343 from Hitachi Chemical Co., Ltd., Watersol S-118, CD-520, Bekkolite M-6402-50, and M-6201-40IM from DIC Corporation, Harima Chemicals Co., Ltd., and Haridip WH-1188 from Harima Chemicals, Ltd., and ES3604 and ES6538 from Nippon Yupika Co., Ltd. Examples of polyacrylic polyol resins include polyacrylic polyol resins such as Barnock WE-300 and WE-304 manufactured by DIC Corporation, polyvinyl alcohol resins such as Kuraray Poval PVA-203 manufactured by Kuraray Co., Ltd., polyvinyl acetal resins such as BX-1, BM-1, KS-1, and KS-5 manufactured by Sekisui Chemical Co., Ltd., polyamide resins such as Trezin FS-350 manufactured by Nagase ChemteX Corporation, carboxyl group-containing resins such as Aquaric manufactured by Nippon Shokubai Co., Ltd. and Finelex SG2000 manufactured by Namari Corporation, polyamine resins such as Laccamide manufactured by DIC Corporation, and polythiol resins such as QE-340M manufactured by Toray Industries, Inc. Among these, polyvinyl acetal resins and polyester polyol resins are more preferred from the viewpoint of polymerizability and uniformity of the second layer 214.

[0272] The weight-average molecular weight (Mw) of the resin is preferably in the range of 5,000 to 300,000. The molecular weight of the resin can be measured, for example, using the gel permeation chromatography "HLC-8120" manufactured by Tosoh Corporation, and calculated in polystyrene equivalent.

[0273] Methods for quantifying functional groups in resins include titration of carboxyl groups using potassium hydroxide, titration of amino groups using sodium nitrite, titration of hydroxyl groups using acetic anhydride and potassium hydroxide, titration of thiol groups using 5,5'-dithiobis(2-nitrobenzoic acid), and calibration curves obtained from IR spectra of samples with varying functional group introduction ratios.

[0274] Next, specific examples of resins are shown below.

[0275] [Table 20]

[0276] 〔solvent〕 For preparing the coating solution for forming the second layer 214, any solvent can be arbitrarily selected from, for example, alcohol-based, aromatic-based, halogenated hydrocarbon-based, ketone-based, ketone alcohol-based, ether-based, ester-based, etc. More specifically, for example, organic solvents such as methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellsolve, ethyl cellsolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, and toluene can be used. These solvents can be used individually or in mixtures of two or more.

[0277] [Confirmation of curing properties] The curability of the second layer 214 can be confirmed, for example, as follows: A coating film of a coating solution for forming the second layer 214, containing a melamine compound or guanamine compound, a resin, and an electron transporting substance, is formed on an aluminum sheet using a Meyer bar. This coating film is then heated and dried at 160°C for 40 minutes to form the second layer 214. The obtained second layer 214 is immersed in a cyclohexanone / ethyl acetate = 1 / 1 mixed solvent for 2 minutes and dried at 160°C for 5 minutes. The mass of the second layer 214 is checked before and after immersion to confirm that there is no elution (mass difference within ±2%).

[0278] <<Photoelectric Conversion Device>> The photoelectric conversion device has a plurality of photoelectric conversion elements according to one embodiment of the present invention. When multiple elements are connected together, it can also be called a photoelectric conversion module. The elements may be stacked to increase the output voltage. The photoelectric conversion device also has a photoelectric conversion element according to one embodiment of the present invention and an inverter. The inverter may be a converter that converts DC to AC. The photoelectric conversion device may have a power storage unit connected to the photoelectric conversion element. The power storage unit is not limited as long as it can store electricity. Examples include secondary batteries using lithium ions, all-solid-state batteries, electric double-layer capacitors, etc.

[0279] Figure 5 shows an example of a mobile body according to this embodiment. The mobile body 30 comprises a photoelectric conversion element 31 according to one embodiment of the present invention and a vehicle body 32 equipped with this photoelectric conversion element. The photoelectric conversion element 31 is positioned in a location on the vehicle 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. The electrical energy generated from the power of the mobile body 30 may also 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.

[0280] The mobile device 30 may be, for example, an automobile, a ship, an aircraft, or a drone. The structure of the mobile device 30's body 32 is not particularly limited, but it is preferably made of a high-strength material.

[0281] Figure 6 shows an example of a building material according to this embodiment. The building material may be the roof of a building. The building material 40 has a photoelectric conversion element 41 according to one embodiment of the present invention, a protective member 42 for protecting the photoelectric conversion element, a heat dissipation member 43, and an exterior 44. That is, the building material according to this embodiment has a photoelectric conversion element 41 according to the present invention and a protective member 42 or a heat dissipation member 43.

[0282] The building material 40 according to this embodiment may have a heat dissipation member 43 with a higher thermal conductivity than the photoelectric conversion element 41. When used on a roof or the like, the temperature of the photoelectric conversion element 41 may rise due to sunlight, which may reduce the photoelectric conversion efficiency. 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, and liquid resins.

[0283] The building material 40 according to this embodiment has an exterior facade 44. The exterior facade 44a and the exterior facade 44b may have different colors or the same color. The exterior facade 44a and the exterior facade 44b may be made of the same material or different materials. Paint and transparent substrates may be used for the exterior facade 44. Materials with low light absorption and high heat shielding properties are preferred.

[0284] The building material 40 according to this embodiment has a photoelectric conversion layer containing perovskite, which makes it a building material with excellent design, and also has a reflective layer, which makes it highly efficient at photoelectric conversion. In other words, it is possible to create a building material that is highly efficient at photoelectric conversion and has vibrant colors. [Examples]

[0285] The present invention will be described in more detail below using examples and comparative examples. The present invention is not limited in any way by the following examples, unless it exceeds the gist of the invention. In the following examples, "parts" refers to mass unless otherwise specified.

[0286] ≪First Embodiment (Reference Form)≫ <Particle selection and manufacturing examples> (Particles 1-8: Titanium dioxide particles) Titanium dioxide (manufactured by Teika) with a volume-average particle size of 50-600 nm was used.

[0287] (Particle 9: Zinc oxide particles) Zinc oxide with a volume-average particle size of 200 nm (manufactured by Hakusui Tech) was used.

[0288] (Particle 10: Tin oxide-coated titanium oxide particles) Titanium oxide particles with a volume-average particle size of 200 nm were used as the core material particles.

[0289] 200g of core material particles were dispersed in water to form a 2L aqueous suspension, which was heated to 70°C. 226.2g of stannous chloride (SnCl4·5H2O) was dissolved in 500mL of 3 mol / L hydrochloric acid (stannic acid solution A), and 5.2g of sodium tungstate (Na2WO4·2H2O) was dissolved in 500mL of 5 mol / L sodium hydroxide solution (alkaline solution B). These solutions were simultaneously added dropwise over 6 hours until the pH of the suspension reached 2-3. After the addition was complete, the suspension was filtered, washed, and dried at 110°C for 8 hours. This dried material was heat-treated at 650°C for 1 hour under a nitrogen gas flow (1L / min) to produce particle 10.

[0290] (Particle 11: Nb-doped titanium dioxide coated titanium dioxide particles) Titanium oxide particles with a volume-average particle size of 200 nm were used as the core material particles.

[0291] A titanium-niobium sulfate solution containing 33.7 g of titanium (in TiO2 equivalent) and 2.9 g of niobium (in Nb2O5 equivalent) was prepared. 100 g of core material particles were dispersed in pure water to make a 1 L suspension, which was heated to 60°C. The titanium-niobium sulfate solution and 10 mol / L sodium hydroxide were added dropwise over 3 hours until the pH of the suspension reached 2-3. After the entire amount had been added, the pH was adjusted to near neutral, and a flocculant was added to allow the solid components to settle. The supernatant was removed, filtered, washed, and dried at 110°C to obtain an intermediate containing 0.1 wt% organic matter from the flocculant (in C equivalent). This intermediate was calcined in nitrogen gas at 800°C for 1 hour to produce particle 11.

[0292] [Table 21]

[0293] <Example of preparation of coating solution for reflective layer> When the reflective layer did not contain a binder, the particles were dissolved in 1500 parts of 1-methoxy-2-propanol as a solvent to obtain a solution. 30 parts of the particles were added to this solution, and this was placed in a vertical sand mill using 1500 parts of glass beads with an average particle size of 1.0 mm as the dispersion medium. The dispersion was carried out for 4 hours at a dispersion temperature of 23±3°C and a rotation speed of 1500 rpm (peripheral speed of 5.5 m / s) to obtain a dispersion. The glass beads were removed from this dispersion using a mesh to prepare the reflective layer coating.

[0294] When a binder material was to be included in the reflective layer, a phenolic resin or polyamide resin was dissolved in 1500 parts of 1-methoxy-2-propanol as a solvent to obtain a solution. The prepared particles were added to this solution in any weight ratio to the resin, and this was placed in a vertical sand mill using 1500 parts of glass beads with an average particle size of 1.0 mm as the dispersion medium. The dispersion was carried out for 4 hours at a dispersion temperature of 23±3℃ and a rotation speed of 1500 rpm (peripheral speed of 5.5 m / s) to obtain a dispersion. The glass beads were removed from this dispersion using a mesh to prepare the reflective layer coating.

[0295] <Example of preparation of photoelectric conversion layer coating> (Paint 1: MAPbI3 paint) Four parts of lead iodide and 1.4 parts of methylammonium iodide were dissolved in 4.5 parts of dimethylformamide as a solvent, and the mixture was stirred at 60°C for 24 hours to achieve complete dissolution.

[0296] (Paint 2: MAPbBr3 paint) 3.4 parts lead bromide and 1 part methylammonium bromide were dissolved in 4.5.5 parts dimethylformamide as a solvent, and the mixture was stirred at 60°C for 24 hours to achieve complete dissolution.

[0297] (Paint 3-5: MAPbI) (1-x) Br x paint) Paint 1 and Paint 2 were prepared by mixing them in the weight ratios shown in Table 22.

[0298] [Table 22]

[0299] <Example 1-1> Under an N2 atmosphere, Spiro-OMeTAD (180 mg) as a hole transport material was dissolved in chlorobenzene (1 mL) on an ITO glass substrate. To this chlorobenzene solution, an acetonitrile solution (37.5 μL) prepared by dissolving lithium-bis(trifluoromethanesulfonyl)imide (170 mg) in acetonitrile (1 mL) and t-butylpyridine (TBP, 17.5 μL) were added and mixed to prepare a hole transport material solution. This solution was coated onto the perovskite layer by spin coating. After coating, it was fired at 100°C for 10 minutes to form a hole transport layer with a thickness of 300 nm.

[0300] Next, a photoelectric conversion layer coating 4 was formed on the hole transport layer by spin coating, and then baked at 100°C for 10 minutes to form a 300 nm thick photoelectric conversion layer.

[0301] Next, a coating consisting of phenolic resin dispersed in a weight ratio of 6 particles to 80 / 1 was formed on the photoelectric conversion layer by spin coating, and then baked at 130°C for 30 minutes to form a 300 nm thick reflective layer.

[0302] Subsequently, a layer with a thickness of 80 nm and an area of ​​0.09 cm² was placed on the reflective layer. 2 A photoelectric conversion element was fabricated by depositing gold electrodes using a vacuum deposition method.

[0303] <Examples 1-2> Similar to Example 1-1, the layers up to the photoelectric conversion layer were laminated, and a coating with dispersed particles 6 was formed by spin coating. This coating was then baked at 130°C for 30 minutes to form a 300 nm thick reflective layer. Subsequently, a photoelectric conversion element was fabricated by depositing an 80 nm thick gold electrode on the reflective layer using vacuum deposition.

[0304] <Examples 1-3 to 1-19> The layers were laminated up to the charge transport layer in the same manner as in Example 1-1, and the photoelectric conversion layer coating shown in Table 23 was deposited by spin coating. The layers were then baked at 100°C for 10 minutes to form an active layer with a thickness of 300 nm. Next, the coating with dispersed particles shown in Table 23 was deposited by spin coating and baked at 130°C for 30 minutes to form a reflective layer with a thickness of 300 nm. Subsequently, a layer with a thickness of 80 nm and an area of ​​0.09 cm² was applied to the reflective layer. 2 A photoelectric conversion element was fabricated by depositing gold electrodes using a vacuum deposition method.

[0305] <Examples 1-20> The preparation was carried out in the same manner as in Example 1-1, except that the weight ratio of particle 6 to phenolic resin was set to 100 / 1.

[0306] <Example 1-21> The preparation was carried out in the same manner as in Example 1-1, except that the weight ratio of particle 6 to phenolic resin was set to 1 / 2.

[0307] <Examples 1-22> The material was prepared in the same manner as in Examples 1 and 20, except that polyamide was used as the binder resin.

[0308] <Examples 1-23> The material was prepared in the same manner as in Example 1-21, except that polyamide was used as the binder resin.

[0309] <Comparative Example 1-1> The preparation was carried out in the same manner as in Example 1-1, except that titanium oxide with a volume-average particle size of 30 nm was used instead of particle 6.

[0310] <Comparative Example 1-2> The preparation was carried out in the same manner as in Example 1-2, except that titanium oxide with a volume-average particle size of 30 nm was used instead of particle 6.

[0311] <Comparative Example 1-3> The preparation was carried out in the same manner as in Examples 1-14, except that titanium oxide with a volume-average particle size of 30 nm was used instead of particle 6.

[0312] <Rating> The following evaluations were performed on the photoelectric conversion elements obtained in each example and comparative example.

[0313] (Wavelength α at which the reflectivity of the reflective layer is maximized in the visible light region) Figure 7 shows the spectrum of the element of Example 1-1. Figure 7(a) is the reflectance spectrum of the reflective layer, and Figure 7(b) is the absorption spectrum of the photoelectric conversion layer. From Figure 7(a), the wavelength α at which the reflectance of the reflective layer is maximum in the visible light region (360 nm to 830 nm) is 656 nm. Also, from Figure 7(b), the optical absorption coefficient of the photoelectric conversion layer is 1.92 (AU), which is the maximum value in the visible light region, at 360 nm. On the other hand, the optical absorption coefficient at wavelength α (656 nm) is 0.64 (AU). Therefore, the element of Example 1-1 had a wavelength α within the range of wavelengths where the optical absorption coefficient of the photoelectric conversion layer is 1 / 5 or more of the maximum value in the visible light region.

[0314] Furthermore, in the other embodiments, the wavelength α of the elements was within the range of wavelengths in which the optical absorption coefficient of the photoelectric conversion layer was 1 / 5 or more of the maximum value in the visible light region.

[0315] On the other hand, in the comparative example, the wavelength α was outside the range of wavelengths in which the optical absorption coefficient of the photoelectric conversion layer is 1 / 5 or more of the maximum value in the visible light region.

[0316] (Evaluation of power generation efficiency) A power supply (KEITHLEY, Model 236) is connected between the electrodes of the photoelectric conversion element, and the intensity is set to 100 mW / cm². 2 Using a solar simulation (manufactured by Yamashita Densou Co., Ltd.), the photoelectric conversion efficiency was evaluated by irradiating a constant amount of light from the glass substrate side and measuring the generated current and voltage.

[0317] [Table 23]

[0318] As described above, the photoelectric conversion element according to the present invention showed superior photoelectric conversion efficiency compared to the comparative example. Furthermore, as measured, it not only exhibited excellent photoelectric conversion efficiency but also produced a vividly colored element.

[0319] ≪Second Embodiment (Reference Form)≫ [Manufacturing of conductive particles] (Conductive particle 1) Titanium oxide particles with an average major axis diameter a and average minor axis diameter b of 50 nm were used as core material particles. A titanium-niobium sulfate solution containing 33.7 g of titanium (in TiO2 equivalent) and 2.9 g of niobium (in Nb2O5 equivalent) was prepared. 100 g of core material particles were dispersed in pure water to make a 1 L suspension, which was heated to 60°C. The titanium-niobium sulfate solution and 10 mol / L sodium hydroxide were added dropwise over 3 hours until the pH of the suspension was between 2 and 3. After the entire amount had been added, the pH was adjusted to near neutral, and a flocculant was added to settle the solids. The supernatant was removed, filtered and washed, and dried at 110°C to obtain an intermediate containing 0.1 mass% of organic matter derived from the flocculant (in C equivalent). This intermediate was calcined in nitrogen gas at 800°C for 1 hour to obtain conductive particle 1.

[0320] (Conductive particles 2 to 6) Conductive particles 2 to 6, shown in Table 24, were manufactured in the same manner as the manufacturing process for conductive particle 1, except that the average major axis diameter a and average minor axis diameter b of the core material particles were changed.

[0321] (Conductive particle 7) Conductive particles 7 were manufactured in the same manner as the manufacturing process for conductive particles 2, except that the coating conditions were changed so that the average major axis diameter a and average minor axis diameter b at the end of manufacturing were both 250 nm.

[0322] (Conductive particle 8) Titanium oxide particles with average major axis diameter a and average minor axis diameter b of 200 nm were used as core material particles. 200 g of core material particles were dispersed in water to make a 2 L aqueous suspension, which was heated to 70°C. A stannic acid solution prepared by dissolving 226.2 g of stannous chloride (SnCl4·5H2O) in 500 mL of 3 mol / L hydrochloric acid and a 5 mol / L sodium hydroxide solution were simultaneously added dropwise over 6 hours until the pH of the suspension was between 2 and 3 (parallel addition). After the addition was complete, the suspension was filtered and washed, and dried at 110°C for 8 hours. This dried material was heat-treated in a nitrogen gas stream (1 L / min) at 650°C for 1 hour to produce conductive particles 8.

[0323] (Conductive particle 9) Conductive particles 9, as shown in Table 24, were prepared in the same manner as the preparation process for conductive particles 8 described above, except that orthophosphoric acid was added to the tin acid solution so that the doping amount was 5.0% by mass in terms of P2O5.

[0324] (Conductive particles 10) Conductive particles 10, as shown in Table 24, were prepared in the same manner as the preparation process for conductive particles 8 described above, except that tantalum(V) chloride was added to the tin acid solution so that the doping amount was 5.0% by mass in terms of Ta2O5.

[0325] (Conductive particle 11) Conductive particles 11, as shown in Table 24, were prepared in the same manner as the preparation process for conductive particles 8 described above, except that niobium(V) chloride was added to the tin acid solution so that the doping amount was 5.0% by mass in terms of Nb2O5.

[0326] (Conductive particle 12) Conductive particles 12, as shown in Table 24, were prepared in the same manner as the preparation process for conductive particles 8 described above, except that sodium tungstate dihydrate was added to the tin acid solution so that the doping amount was 5.0% by mass in terms of WO3.

[0327] (Conductive particle 13) Conductive particles 13, as shown in Table 24, were prepared in the same manner as the preparation process for conductive particles 8 described above, except that sodium fluoride was added to the tin acid solution so that the doping amount in terms of F was 1.0 mass%.

[0328] (Conductive particle 14) Titanium oxide particles with an average major axis diameter a and average minor axis diameter b of 200 nm were used as core material particles. 250 g of core material particles were dispersed in water to make a 2 L aqueous suspension, which was heated to 50°C. A zinc chloride aqueous solution, prepared by dissolving 161.5 g of zinc chloride (ZnCl2) in 3 L of water, and a 5 mol / L sodium hydroxide solution were simultaneously added dropwise over 2 hours (parallel addition) until the pH of the suspension reached 10. After the addition was complete, the suspension was filtered and washed, and dried at 110°C for 12 hours. This dried material was heat-treated in a nitrogen gas stream (1 L / min) at 550°C for 1 hour to produce conductive particles 14.

[0329] (Conductive particle 15) Conductive particles 15, as shown in Table 24, were prepared in the same manner as the preparation process for conductive particles 14 described above, except that aluminum(III) chloride was added to the tin acid solution so that the doping amount was 3.0% by mass in terms of Al2O3.

[0330] (Conductive particle 16) Conductive particles 16, as shown in Table 24, were prepared in the same manner as the preparation process for conductive particles 14 described above, except that gallium(III) chloride was added to the tin acid solution so that the doping amount was 3.0% by mass in terms of Ga2O3.

[0331] (Conductive particle 17) The conductive particles 17 shown in Table 24 were prepared in the same manner as the preparation process for conductive particles 8 described above, except that barium sulfate particles with an average major axis diameter a and an average minor axis diameter b of 300 nm were used as core material particles.

[0332] (Conductive particle 18) Conductive particles 18, as shown in Table 24, were prepared in the same manner as the preparation process for conductive particles 17 described above, except that orthophosphoric acid was added to the tin acid solution so that the doping amount was 5.0% by mass in terms of P2O5.

[0333] (Conductive particle 19) Conductive particles 19, as shown in Table 24, were prepared in the same manner as conductive particle 1, except that strontium titanate particles with an average major axis diameter a and an average minor axis diameter b of 100 nm were used as core material particles.

[0334] (Conductive particles 20) Conductive particles 20, as shown in Table 24, were prepared in the same manner as the preparation process for conductive particles 1, except that barium titanate particles with an average major axis diameter a and an average minor axis diameter b of 150 nm were used as core material particles.

[0335] (Conductive particle 21) As core material particles, strontium titanate particles with average major axis diameter a and average minor axis diameter b of 100 nm were used. 7 g of core material particles were mixed and stirred with 140 mg of methyl hydrogen polysiloxane while operating an edge runner, under a linear load of 588 N / cm (60 kg / cm) for 30 minutes. The stirring speed at this time was 22 rpm. Carbon black particles (volume average particle size 20 nm, volume resistivity 1.0 × 10⁻⁶) were added to the mixture. 2 7 g of (Ω·cm, pH 8.0) was added while operating the edge runner, and the mixture was further mixed and stirred for 60 minutes under a linear load of 588 N / cm (60 kg / cm). After carbon black was attached to the surface of the strontium titanate particles coated with methyl hydrogen polysiloxane in this manner, the particles were dried in a dryer at 80°C for 60 minutes to produce the conductive particles 21 shown in Table 24.

[0336] (Conductive particles 22, 23) As core material particles, strontium titanate particles with an average major axis diameter a and an average minor axis diameter b of 100 nm were used. A copper film with a thickness of 10 nm was formed on the surface of the strontium titanate particles by electroless plating to obtain conductive particles 22 shown in Table 24. Similarly, a silver film with a thickness of 10 nm was formed by electroless silver plating to produce conductive particles 23 shown in Table 24.

[0337] (Conductive particles 24) Conductive particles 24, as shown in Table 24, were prepared in the same manner as the preparation process for conductive particles 8, except that silica particles with an average major axis diameter a and an average minor axis diameter b of 150 nm were used as core material particles.

[0338] (Conductive particles 25) Conductive particles 25, as shown in Table 24, were prepared in the same manner as the preparation process for conductive particles 8, except that alumina particles with an average major axis diameter and average minor axis diameter of 250 nm were used as core material particles.

[0339] (Conductive particles 26) Conductive particles 26, as shown in Table 24, were prepared in the same manner as the preparation process for conductive particles 21, except that silica particles with an average major axis diameter a and an average minor axis diameter b of 150 nm were used as core material particles.

[0340] (Conductive particles 27 to 29) For comparative examples, conductive particles were prepared as shown in Table 24: tin oxide particles with average major axis diameter a and average minor axis diameter b of 200 nm, zinc oxide particles with average major axis diameter a and average minor axis diameter b of 150 nm, and carbon black particles with a volume average particle diameter of 20 nm.

[0341] [Table 24]

[0342] (Example 2-1) Spiro-OMeTAD (180 mg) was dissolved in chlorobenzene (1 mL) as a hole transport material. To this chlorobenzene solution, an acetonitrile solution (37.5 μL) prepared by dissolving lithium-bis(trifluoromethanesulfonyl)imide (170 mg) in acetonitrile (1 mL) and t-butylpyridine (TBP, 17.5 μL) were added and mixed to prepare a hole transport material solution. Under an N2 atmosphere, the hole transport material solution was applied to an ITO glass substrate by spin coating and fired at 100°C for 10 minutes to form a hole transport layer with a thickness of 300 nm.

[0343] Next, as a coating solution for the active layer, 4 parts lead iodide and 1.4 parts methylammonium iodide were dissolved in 4.5 parts dimethylformamide as a solvent, and the mixture was stirred at 60°C for 24 hours to prepare the solution. This was then deposited onto the hole transport layer by spin coating and fired at 100°C for 10 minutes to form an active layer with a thickness of 300 nm.

[0344] Phenolic resin as a binding material (phenolic resin monomer / oligomer) (product name "Pryofen J-325", manufactured by DIC, resin solids content: 60% by mass, density after curing: 1.3 g / cm³) 2 5 parts of the compound were dissolved in 1500 parts of 1-methoxy-2-propanol as a solvent to obtain a solution. 30 parts of conductive particles 1 were added to this solution, and this was placed in a vertical sand mill using 1500 parts of glass beads with an average particle size of 1.0 mm as a dispersion medium. Dispersion treatment was carried out for 4 hours under conditions of dispersion temperature 23±3℃ and rotation speed 1500 rpm (peripheral speed 5.5 m / s) to obtain a dispersion. The glass beads were removed from this dispersion using a mesh to prepare a coating solution for the conductive layer.

[0345] Next, the above-mentioned conductive layer coating solution was applied onto the activated layer by spin coating. After application, it was fired in air at 150°C for 10 minutes to form a conductive layer with a thickness of 500 nm.

[0346] Subsequently, a conductive layer with a thickness of 80 nm and an area of ​​0.09 cm² was placed on top. 2 A photoelectric conversion element was fabricated by depositing gold electrodes using a vacuum deposition method.

[0347] A power supply (KEITHLEY, Model 236) is connected between the electrodes of the above-mentioned photoelectric conversion element, and the intensity is set to 100 mW / cm². 2 The photoelectric conversion efficiency was evaluated by irradiating a constant amount of light using a solar simulation software (manufactured by Yamashita Densou Co., Ltd.) and measuring the generated current and voltage. The results for short-circuit current density and photoelectric conversion efficiency are shown in Table 25.

[0348] (Examples 2-2 to 2-26) A photoelectric conversion element was fabricated in the same manner as in Example 2-1, except that the conductive particles used in the preparation of the coating solution for the conductive layer were changed to conductive particles 2 to 26 shown in Table 24, and the photoelectric conversion efficiency was evaluated. The results for short-circuit current density and photoelectric conversion efficiency are shown in Table 25.

[0349] (Examples 2-27) The coating solution for the conductive layer was prepared as follows.

[0350] One part of butyral resin (product name: BM-1, manufactured by Sekisui Chemical Co., Ltd.) and one part of blocked isocyanate resin (product name: TPA-B80E, 80% solution, manufactured by Asahi Kasei Co., Ltd.) were dissolved in a mixed solvent of 400 parts methyl ethyl ketone and 700 parts 1-butanol to obtain a solution. Twenty parts of conductive particles 2 shown in Table 24 were added to this solution, and this was placed in a vertical sand mill using 1100 parts of glass beads with an average particle size of 1.0 mm as the dispersion medium. Dispersion treatment was carried out for 4 hours at a rotation speed of 1500 rpm (peripheral speed 5.5 m / s) in an atmosphere of 25 ± 3 °C to prepare a coating solution for the conductive layer.

[0351] A photoelectric conversion element was fabricated in the same manner as in Example 2-1, except for using the above-mentioned conductive layer coating solution, and the photoelectric conversion efficiency was evaluated. The results for short-circuit current density and photoelectric conversion efficiency are shown in Table 25.

[0352] (Examples 2-28) A photoelectric conversion element was fabricated in the same manner as in Example 2-27, except that the conductive particles used in the preparation of the coating solution for the conductive layer were changed to conductive particles 9 shown in Table 24, and the photoelectric conversion efficiency was evaluated. The results for short-circuit current density and photoelectric conversion efficiency are shown in Table 25.

[0353] (Examples 2-29) A photoelectric conversion element was fabricated in the same manner as in Example 2-1, except that phenolic resin was not used in the preparation of the coating solution for the conductive layer, and conductive particles 2 shown in Table 24 were used as the conductive particles. The photoelectric conversion efficiency was then evaluated. The results for short-circuit current density and photoelectric conversion efficiency are shown in Table 25.

[0354] (Comparative Examples 2-1 to 2-3) A photoelectric conversion element was fabricated in the same manner as in Example 2-1, except that the conductive particles used in the preparation of the coating solution for the conductive layer were changed to one of the conductive particles 27 to 29 shown in Table 24, and the photoelectric conversion efficiency was evaluated. The results for short-circuit current density and photoelectric conversion efficiency are shown in Table 25.

[0355] Furthermore, for the elements in Comparative Examples 2-1 and 2-2, the wavelength α at which the reflectivity of the reflective layer is maximized in the visible light region was outside the range of wavelengths where the optical absorption coefficient of the photoelectric conversion layer is 1 / 5 or more of the maximum value in the visible light region.

[0356] [Table 25]

[0357] ≪Third Embodiment≫ <Example 3-1> 3.27 parts of exemplary compound (E-1-1) as an electron transport compound, 6.2 parts of exemplary compound (I-8) as an isocyanate compound, and 1.29 parts of butyral resin (trade name: BM-1, manufactured by Sekisui Chemical Co., Ltd.) as a resin were dissolved in a mixed solution of 50 parts methyl ethyl ketone and 50 parts dimethylacetamide. To the resulting solution, 0.031 parts of dioctyl tin diurarate were added as a catalyst to prepare a coating solution for the underlayer, which would be the second layer 214. This coating solution was applied by spin coating onto an FTO glass substrate 216 on which the cathode 215 was formed. After application, the substrate was heated at 160°C for 30 minutes to polymerize (cur) it, forming an underlayer with a thickness of 500 nm.

[0358] Next, lead iodide was dissolved in N,N-dimethylformamide (DMF) as a metal halide compound to prepare a 1M solution. This solution was then deposited on the substrate layer by spin coating. Furthermore, methylammonium iodide was dissolved in 2-propanol as an amine compound to prepare a 1M solution. The sample with the lead iodide film was immersed in this solution, and then fired at 100°C in air for 10 minutes to form a perovskite layer as the first layer 213 with a thickness of 500 nm.

[0359] Next, Spiro-OMeTAD (180 mg) as a hole transport material was dissolved in chlorobenzene (1 mL). To this chlorobenzene solution, an acetonitrile solution (37.5 μL) prepared by dissolving lithium-bis(trifluoromethanesulfonyl)imide (170 mg) in acetonitrile (1 mL) and t-butylpyridine (TBP, 17.5 μL) were added and mixed to prepare a hole transport material solution. This solution was applied to the perovskite layer by spin coating. After application, it was fired in air at 100°C for 10 minutes to form a hole transport layer as a third layer 212 with a thickness of 300 nm.

[0360] Subsequently, a photoelectric conversion element was fabricated by depositing a gold electrode, which serves as anode 211 with a thickness of 80 nm, onto the hole transport layer using vacuum deposition.

[0361] [evaluation] [Structure of the underlying layers] The structure of the underlying layer was analyzed as follows: A photoelectric conversion element for structural analysis of the underlying layer was immersed in a chlorobenzene solvent for 5 minutes, and ultrasonic waves were applied to exfoliate the hole transport layer. Next, the perovskite layer was polished using lapping tape (C2000: manufactured by Fuji Photo Film Co., Ltd.), and then dried at 100°C for 10 minutes to obtain the photoelectric conversion element for structural analysis of the underlying layer. Furthermore, it was confirmed using the FTIR-ATR method that no components of the hole transport layer or perovskite layer remained on the surface of the underlying layer. The central part of the photoelectric conversion element was cut out into a 5 mm square and used as a sample for structural analysis of the underlying layer. 13 The structure represented by formula (U1) (specific examples in Tables 1 to 11) and D were confirmed by 13C-NMR measurement, mass spectrometry measurement, MS spectroscopy measurement by pyrolysis GC analysis, and characteristic absorption measurement by infrared spectroscopy. 1 Table 26 shows the number of atoms in the main chain of the structure.

[0362] [Evaluation of power generation efficiency] A power supply (KEITHLEY, Model 236) is connected between the electrodes of the photoelectric conversion element, and the intensity is set to 100 mW / cm². 2The photoelectric conversion efficiency was evaluated by irradiating a constant amount of light using a solar simulation software (manufactured by Yamashita Densou Co., Ltd.) and measuring the generated current and voltage. The results for short-circuit current density and photoelectric conversion efficiency are shown in Table 26.

[0363] <Examples 3-2 to 3-73 (Examples 3-14, 3-16, 3-23 to 3-29, 3-31, 3-33, 3-44, 3-45, 3-48 to 3-73 are for reference only)> A photoelectric conversion element was fabricated and evaluated in the same manner as in Example 3-1, except that the electron transport compound and isocyanate compound in the coating solution for the underlayer used in Example 3-1 were changed as shown in Tables 26 to 27.

[0364] <Comparative Examples 3-1 to 3-3> A photoelectric conversion element was fabricated and evaluated in the same manner as in Example 3-1, except that the coating solution for the underlayer used in Example 3-1 was modified as shown in Table 28, by using only electron-transporting compounds and omitting isocyanate compounds and resins.

[0365] <Comparative Example 3-4> A photoelectric conversion element was fabricated and evaluated in the same manner as in Example 3-1, except that the coating solution for the underlayer used in Example 3-1 was modified as shown in Table 28, by using an isocyanate compound and a resin instead of an electron transport compound.

[0366] [Table 26]

[0367] [Table 27]

[0368] [Table 28]

[0369] In Tables 26 to 28, parts by mass of electron-transporting compounds indicate the content (parts by mass) of electron-transporting compounds in the undercoat coating solution. Parts by mass of isocyanate compounds indicate the content (parts by mass) of isocyanate compounds in the undercoat coating solution. Parts by mass of resins indicate the content (parts by mass) of resins in the undercoat coating solution.

[0370] In the comparison between the examples and comparative examples, as shown in Comparative Examples 3-1 to 3-3, when the underlayer was formed using only electron-transporting compounds, dissolution of the underlayer was observed when the perovskite layer was applied, resulting in a significant deterioration of film properties. Therefore, it is thought that the characteristics as a photoelectric conversion element could not be measured. Furthermore, in Comparative Example 3-4, since there was no electron-transporting compound, it is thought that electrons could not move from the perovskite layer.

[0371] <Example 3-74 (Reference Example)> A coating solution for the underlayer was prepared by dissolving 5 parts of electron transport compound (E-1-8), 3.5 parts of melamine compound (C1-3), 3.4 parts of resin 1, and 0.1 parts of dodecylbenzenesulfonic acid as a catalyst in a mixed solvent of 100 parts of dimethiacetamide and 100 parts of methyl ethyl ketone. This coating solution was applied to an FTO glass substrate by spin coating. After application, the substrate was heated at 160°C for 30 minutes to polymerize (cur) it, forming an underlayer with a thickness of 500 nm. Subsequently, a photoelectric conversion element was fabricated and evaluated in the same manner as in Example 3-1.

[0372] <Examples 3-75 to 3-141 (Reference Examples)> A photoelectric conversion element was fabricated and evaluated in the same manner as in Example 3-74, except that the electron transport compound, melamine compound, and guanamine compound in the coating solution for the underlayer used in Example 3-74 were changed as shown in Tables 29 to 30.

[0373] <Comparative Examples 3-5 to 3-7> A photoelectric conversion element was fabricated and evaluated in the same manner as in Example 3-74, except that the coating solution for the underlayer used in Example 3-74 was modified as shown in Table 31, by using only electron-transporting compounds and omitting melamine compounds, guanamine compounds, and resins.

[0374] <Comparative Example 3-8> A photoelectric conversion element was fabricated and evaluated in the same manner as in Example 3-74, except that the coating solution for the underlayer used in Example 3-74 was modified as shown in Table 31, by using melamine compounds, guanamine compounds, and resin instead of electron transport compounds.

[0375] [Table 29]

[0376] [Table 30]

[0377] [Table 31]

[0378] In Tables 29 to 31, parts by mass of electron-transporting compounds indicate the content (parts by mass) of electron-transporting compounds in the undercoat coating solution. Parts by mass of melamine compounds and guanamine compounds indicate the content (parts by mass) of melamine compounds and guanamine compounds in the undercoat coating solution. Parts by mass of resin indicates the content (parts by mass) of resin in the undercoat coating solution.

[0379] In the comparison between the examples and comparative examples, as shown in Comparative Examples 3-5 to 3-7, when the underlayer was formed using only electron-transporting compounds, dissolution of the underlayer was observed when the perovskite layer was applied, resulting in a significant deterioration of film properties. Therefore, it is thought that the characteristics as a photoelectric conversion element could not be measured. Furthermore, in Comparative Example 3-8, since there was no electron-transporting compound, it is thought that electrons could not move from the perovskite layer. [Explanation of symbols]

[0380] 2: Substrate, 3: First electrode, 4: Charge transport layer, 5: Photoelectric conversion layer, 6: Reflection layer, 7: Second electrode 102: Anode, 104: First layer, 105: Second layer, 106: Cathode 211: Anode, 212: Third layer, 213: First layer, 214: Second layer, 215: Cathode, 216: Substrate

Claims

1. A first layer containing a perovskite compound is provided between the anode and the cathode, and a second layer is provided between the cathode and the first layer. The photoelectric conversion element is characterized in that the second layer has at least one of the structures represented by the following formula (U1) and the following formula (U2). 【Chemistry 1】 (In formulas (U1) to (U2), R 1 and R 3 Each of these independently represents an alkylene group with 1 to 10 atoms in the substituted or unsubstituted main chain, or a substituted or unsubstituted phenylene group. R 2 This represents an alkylene group having 1 to 10 atoms in a single bond, substituted or unsubstituted main chain, or a substituted or unsubstituted phenylene group. The substituents of the substituted alkylene group are alkyl groups, aryl groups, hydroxyl groups, or halogen atoms. The substituents of the substituted phenylene group are halogen atoms, nitro groups, cyano groups, hydroxyl groups, alkyl groups, or halogen-substituted alkyl groups. R 9 This represents a hydrogen atom or an alkyl group. A 1 This represents one of the groups shown in the following formulas (A-1) to (A-6). B 1 This refers to a group represented by any of the following formulas (B-1) to (B-3). D 1 This refers to a group with 5 to 15 atoms in the main chain, as shown by formula (D) below. E 1 (This is a group represented by any of the following formulas (E-1) to (E-3).) 【Chemistry 2】 (In formula (A-5), R 10 represents a hydrogen atom or an alkyl group.) 【Transformation 3】 (In formulas (B-1) to (B-3), R 6 and R 7 These independently represent an alkylene group with 1 to 5 atoms in the main chain, an alkylene group with 1 to 5 atoms in the main chain substituted with an alkyl group having 1 to 5 carbon atoms, an alkylene group with 1 to 5 atoms in the main chain substituted with a benzyl group, an alkylene group with 1 to 5 atoms in the main chain substituted with an alkylcarbonyl group, or an alkylene group with 1 to 5 atoms in the main chain substituted with a phenyl group. One of the carbon atoms in the main chain of the alkylene group is O, S, NH, or NR 15 (R 15 (is an alkyl group.) It may be replaced by ( ). R 2 This represents an alkylene group having 1 to 10 atoms in a single bond, substituted or unsubstituted main chain, or a substituted or unsubstituted phenylene group. The substituents of the substituted alkylene group are alkyl groups, aryl groups, hydroxyl groups, or halogen atoms. The substituents of the substituted phenylene group are halogen atoms, nitro groups, cyano groups, hydroxyl groups, alkyl groups, or halogen-substituted alkyl groups. R 12 This represents a hydrogen atom or an alkyl group. Ar 2 represents a substituted or unsubstituted phenylene group. The substituents of the substituted phenylene group are a halogen atom, a nitro group, a hydroxyl group, a cyano group, an alkyl group, or an alkyl halide. A 1 and A 2 This represents any of the groups shown in formulas (A-1) to (A-5) above. E 1 This is a group represented by any of the following formulas (E-1) to (E-3). o, p, and q are each independently either 0 or 1, and the sum of o, p, and q is between 1 and 3 (inclusive). The arrow points to the R 3 (This refers to the side that connects.) 【Chemistry 4】 (In formula (D), R 4 , R 5 , R 6 and R 7 These independently represent an alkylene group with 1 to 5 atoms in the main chain, an alkylene group with 1 to 5 atoms in the main chain substituted with an alkyl group having 1 to 5 carbon atoms, an alkylene group with 1 to 5 atoms in the main chain substituted with a benzyl group, an alkylene group with 1 to 5 atoms in the main chain substituted with an alkylcarbonyl group, or an alkylene group with 1 to 5 atoms in the main chain substituted with a phenyl group. One of the carbon atoms in the main chain of the alkylene group is O, S, NH, or NR 15 (R 15 (is an alkyl group.) It may be replaced by ( ). Ar 1 and Ar 2 Each of these independently represents a substituted or unsubstituted phenylene group. The substituents of the substituted phenylene group are a halogen atom, a nitro group, a hydroxyl group, a cyano group, an alkyl group, or an alkyl halide. A 2 This represents a group represented by any of the above formulas (A-1) to (A-6). l, m, n, o, p, and q are each independently either 0 or 1, and the sum of l, m, and n, and the sum of o, p, and q are between 1 and 3 (inclusive). 【Transformation 5】 (In formulas (E-1) to (E-3), R 101 ~R 106 , R 201 ~R 210 , R 301 ~R 304 Each of these independently represents a single bond, a hydrogen atom, a cyano group, a nitro group, a halogen atom, an alkoxycarbonyl group, a carboxyl group, a dialkylamino group, a hydroxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group. 101 ~R 106 One of them, R 201 ~R 210 One of them, R 301 ~R 304 One of these exhibits a single bond. Substituents for the substituted alkyl group include alkyl groups, aryl groups, halogen atoms, and carbonyl groups. Substituents for the substituted aryl group or substituted heterocyclic group include halogen atoms, nitro groups, cyano groups, alkyl groups, halogen-substituted alkyl groups, alkoxy groups, and carbonyl groups.

2. The aforementioned D 1 The photoelectric conversion element according to claim 1, characterized in that the main chain has 10 to 15 atoms.

3. The aforementioned R 4 , R 5 , R 6 and R 7 The photoelectric conversion element according to claim 1 or 2, characterized in that each of them is independently an alkylene group having 1 to 5 atoms in the main chain, or an alkylene group having 1 to 5 atoms in the main chain substituted with a methyl group or an ethyl group.

4. The Ar 1 and Ar 2 The photoelectric conversion element according to any one of claims 1 to 3, characterized in that the group is an unsubstituted phenylene group.

5. A photoelectric conversion module comprising a first photoelectric conversion element and a second photoelectric conversion element, wherein at least one of the first and second photoelectric conversion elements is a photoelectric conversion element according to any one of claims 1 to 4.

6. A photoelectric conversion device characterized by comprising a photoelectric conversion element according to any one of claims 1 to 4, and a power storage unit connected to the photoelectric conversion element.

7. A photoelectric conversion device characterized by comprising a photoelectric conversion element according to any one of claims 1 to 4, and an inverter connected to the photoelectric conversion element.

8. A mobile body characterized by comprising a photoelectric conversion element according to any one of claims 1 to 4, and a body equipped with the photoelectric conversion element.

9. A building material characterized by comprising a photoelectric conversion element according to any one of claims 1 to 4, and a protective member or heat dissipation member for protecting the photoelectric conversion element.

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