Photoelectric conversion element and photoelectric conversion device having the photoelectric conversion element

Abstract

To provide a photoelectric conversion element excellent in photoelectric conversion efficiency.SOLUTION: A photoelectric conversion element has a first electrode 3, a second electrode 7, a photoelectric conversion layer 5 arranged between the first electrode 3 and the second electrode 7, and a reflection layer 6 arranged between one of the first electrode 3 and second electrode 7 and the photoelectric conversion layer 5. A wavelength at which the reflectance in a visible light region of the reflection layer 6 becomes maximum is within the range of a wavelength at which the optical absorption coefficient of the photoelectric conversion layer 5 is one-fifth or more of the maximum value in the visible light region.SELECTED DRAWING: Figure 1

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 solve the problems of fossil energy depletion and the global environmental problems caused by the use of fossil energy, active research is being conducted on renewable and clean alternative energy sources such as solar energy, wind power, and hydropower. Among these, interest in solar cells, which directly convert sunlight into electrical energy, is growing significantly. Here, a solar cell refers to a cell that generates current and voltage by absorbing light energy from sunlight and utilizing the photovoltaic effect, in which electrons and holes are generated. Currently, np diode-type silicon (Si) single crystal-based solar cells, which have a light energy conversion efficiency of over 20%, are widely known and are actually used for solar power generation. Perovskite solar cells, which use compounds with a perovskite structure in the active layer, have attracted attention due to their high power generation efficiency and low cost, and many studies have been conducted on them. Furthermore, the color of the active layer can be changed by adjusting the halogen ratio in the active layer, and it is expected that they will be used to create solar cells with vibrant colors and excellent aesthetics. Non-Patent Document 1 describes a solar cell that uses an organic hybrid perovskite compound. It states that colorful solar cells can be obtained by controlling the band gap of 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 that uses a perovskite compound as a material for the active layer, and that uses N-alkylperylenetetracarboxylic acid diimide as an electron transporting compound in the electron transport layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2015-535390 [Patent Document 2] Japanese Patent Application 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 Summary of the Invention [Problem to be solved by the invention]

[0005] The solar cells described in Non-Patent Document 1, Patent Documents 1 and 2 have room for further improvement in photoelectric conversion efficiency. The present invention has been made in view of the above problems, and an object of the present invention is to provide a photoelectric conversion element having 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 an anode and a cathode, and a second layer between the cathode and the first layer, The second layer is characterized by having at least one of a structure represented by the following formula (U1) and a structure represented by the following formula (U2).

[0007] [ka] (In formulas (U1) to (U2), R 1 and R 3each independently represents a substituted or unsubstituted alkylene group having 1 to 10 atoms in the main chain, or a substituted or unsubstituted phenylene group. R 2 represents a single bond, a substituted or unsubstituted alkylene group having 1 to 10 atoms in the main chain, or a substituted or unsubstituted phenylene group. 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 of the groups represented by the following formulae (A-1) to (A-6). B 1 represents a group represented by any one of the following formulas (B-1) to (B-3). D 1 is a group having 5 to 15 atoms in the main chain, represented by the following formula (D). E 1 is represented by any one of the following formulas (E-1) to (E-3): Ru base )

[0008] [ka] (In formula (A-5), R 10 represents a hydrogen atom or an alkyl group.

[0009] [ka] (In formulas (B-1) to (B-3), R 6 and R 7each 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 is O, S, NH, or NR 15 (R 15 is an alkyl group. R 2 represents a single bond, a substituted or unsubstituted alkylene group having 1 to 10 atoms in the main chain, or a substituted or unsubstituted phenylene group. 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 12 represents a hydrogen atom or an alkyl group. Ar 2 represents a substituted or unsubstituted phenylene group, wherein 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. A 1 and A 2 represents any of the groups represented by the formulae (A-1) to (A-5). E 1 is represented by any one of the following formulas (E-1) to (E-3): Ru base is. o, p, and q each independently represent 0 or 1, and the sum of o, p, and q is 1 or more and 3 or less. The arrow indicates the R 3 )

[0010] [ka] (In formula (D), R 4 , R 5 , R6 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 is O, S, NH, or NR 15 (R 15 is an alkyl group. Ar 1 and Ar 2 each independently represents a substituted or unsubstituted phenylene group, wherein 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. A 2 represents a group represented by any one of the formulae (A-1) to (A-6). l, m, n, o, p, and q each independently represent 0 or 1, and the sum of l, m, and n, and the sum of o, p, and q is 1 or more and 3 or less.

[0011] [ka] (In formulas (E-1) to (E-3), R 101 ~R 106 , R 201 ~R 210 , R 301 ~R 304 R 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. 101 ~R 106 1 of 1, R 201 ~R 210 1 of 1, R 301 ~R 3041 of One , and a single bond. Substituents for the substituted alkyl group include an alkyl group, an aryl group, a halogen atom, and a carbonyl group. Substituents for the substituted aryl group or the substituted heterocyclic group include a halogen atom, a nitro group, a cyano group, an alkyl group, a halogen-substituted alkyl group, an alkoxy group, and a carbonyl group. [Effects of the Invention]

[0012] According to the present invention, a photoelectric conversion element having excellent photoelectric conversion efficiency can be provided. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is an example of a photoelectric conversion element according to an embodiment of the present invention. [Figure 2] 1 is an example of colorimetry according to an embodiment of the present invention. [Figure 3] 1 is a cross-sectional view in the thickness direction, schematically illustrating the configuration of an example of a photoelectric conversion element according to an embodiment of the present invention. [Figure 4] 1 is a schematic diagram illustrating an example of the configuration of a photoelectric conversion element according to one embodiment of the present invention. [Figure 5] 1 is a diagram illustrating an example of a moving body equipped with a photoelectric conversion element according to an embodiment of the present invention. [Figure 6] 1 is an example of a building material provided with a photoelectric conversion element according to one embodiment of the present invention. [Figure 7] FIG. 1 is a diagram showing the spectrum of Example 1-1. DETAILED DESCRIPTION OF THE INVENTION

[0014] <Photoelectric conversion element> First Embodiment (Reference Embodiment) A first embodiment of the present invention will be described in detail below. The photoelectric conversion element according to this embodiment includes 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 one of the first electrode and the second electrode and the photoelectric conversion layer. The wavelength at which the reflective layer maximizes its reflectance in the visible light region is within a wavelength range in which the light absorption coefficient of the photoelectric conversion layer is at least 1 / 5 of the maximum value in the visible light region. The inventors have conducted research and found that this configuration results in a photoelectric conversion element with excellent photoelectric conversion efficiency. In this embodiment, the "photoelectric conversion layer" may also be referred to as a "functional layer" or an "active layer." The photoelectric conversion layer may include a charge transport layer.

[0015] The reflective layer preferably contains 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 light. As a result, the amount of light absorbed by the functional layer increases, improving the photoelectric conversion efficiency.

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

[0017] In this embodiment, the functional layer may have a layer that absorbs light and separates charges, i.e., may be a photoelectric conversion layer. The functional layer preferably has light absorption at wavelengths where the reflective layer has a higher reflectance than other wavelengths. The constituent material of the functional layer may be an organic material, an inorganic material, or a material containing perovskite. A mixed layer of these may also be used.

[0018] The reflective layer according to this embodiment has a high reflectance at wavelengths of light that are highly absorbed by the functional layer. More specifically, the particle size of the reflective layer is 50 nm or more and 600 nm or less, preferably 70 nm or more and 500 nm or less, and more preferably 90 nm or more and 400 nm or less. The particle size of the particles in the reflective layer may be measured as a 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 therebetween, and a reflective layer. The wavelength at which the reflectance of the reflective layer in the visible light region is maximized is within the range of wavelengths absorbed by the photoelectric conversion layer. More preferably, the wavelength at which the reflectance is maximized is within a range of wavelengths at which the optical absorption coefficient of the photoelectric conversion layer is at least one-fifth of the maximum value in the visible light region, and even more preferably, the wavelength at which the reflectance is maximized is within a range of wavelengths at which the optical absorption coefficient of the photoelectric conversion layer is at least half of the maximum value in the visible light region.

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

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

[0022] FIG. 1 is a schematic diagram showing an example of the configuration of a photoelectric conversion element 1 according to this embodiment. A first electrode 3, a charge transport layer 4, a photoelectric conversion layer 5, a reflective layer 6, and a second electrode 7 are provided on a substrate 2. The first electrode 3 and the second electrode 7 may be an anode or a cathode. A current flows when 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 arranged in interchanged 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 a current between the first electrode 3 and the second electrode 7. The charge transport layer 4 is a layer disposed between the photoelectric conversion layer 5 and the two electrodes, and may not be formed in some cases. A configuration in which a plurality of charge transport layers 4 and photoelectric conversion layers 5 are stacked may be used. Such a configuration may also be called a tandem structure.

[0024] The photoelectric conversion element according to this embodiment can be manufactured by preparing a coating solution for each layer described below, coating the layers in the desired order, and drying the coating solution. Examples of the coating method for the coating solution include dip 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] The supporting substrate is preferably a substrate that can form an electrode (anode or cathode) on its main surface and is made of a material that will not be chemically changed when the functional layer that constitutes the photoelectric conversion element is formed. The supporting substrate is also simply called the 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 in which light is taken in from the support substrate side, a substrate having high optical transparency is preferably used as the support substrate.

[0028] Furthermore, when a photoelectric conversion element is provided on an opaque support substrate, light cannot be taken in through the support substrate. Therefore, it is preferable that the electrode farther from the support substrate is transparent or semitransparent. By making the electrode farther from the support substrate transparent or semitransparent, when an opaque support substrate is used, light can be taken in through the electrode farther from the support substrate.

[0029] [electrode] The electrodes are made of a conductive material, such as inorganic compounds such as metals and metal oxides, or organic compounds such as conductive polymers.

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

[0031] One of the first electrode and the second electrode may be an anode and the other may be a cathode. At least one of the anode and the cathode is preferably transparent or semi-transparent.

[0032] The first electrode and the second electrode receive the charges generated in the functional layer, and the charges are extracted to the outside as electrical energy.

[0033] Examples of transparent or semitransparent electrode materials include conductive metal oxides, metals, etc. If these materials are not transparent, they can be made into a thin film with a thickness that allows light to pass through, thereby forming a transparent or semitransparent electrode. Specific examples of transparent or semitransparent electrode materials include indium oxide, zinc oxide, tin oxide, and their composites such as ITO, IZO, FTO, and NESA, as well as gold, platinum, silver, copper, and aluminum.

[0034] There are no particular limitations on the method for forming the electrodes (anode and cathode), and they can be formed on the layer on which the electrodes are to be formed or on the supporting substrate by, for example, vacuum deposition, sputtering, ion plating, plating, coating, or the like.

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

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

[0037] [Hole transport layer] The photoelectric conversion element according to this embodiment 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 serves to reduce the transport of electrons from the photoelectric conversion layer to the anode, thereby reducing the decrease in photoelectric conversion efficiency due to recombination of electrons and holes. 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, and examples thereof include inorganic materials such as CuI and CuNCS, and organic hole transport materials described in paragraphs 0209 to 0212 of JP-A No. 2001-291534. Preferred examples of the organic hole transport material include conductive polymers such as polythiophene, polyaniline, polypyrrole, and polysilane, spiro compounds in which two rings share a central atom having a tetrahedral structure such as C or Si, aromatic amine compounds such as triarylamine, triphenylene compounds, nitrogen-containing heterocyclic compounds, and liquid crystalline cyano compounds.

[0040] The hole transport material is preferably an organic hole transport material that can be applied as a solution and becomes a solid, and specific 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)benzaldehyde diphenylhydrazone, and polyethylenedioxythiophene (PEDOT).

[0041] The thickness of the hole transport layer is not particularly limited, but is preferably 50 μm or less, more preferably 1 nm or more and 10 μm or less, even more preferably 5 nm or more and 5 μm or less, and particularly preferably 10 nm or more and 1 μm or less. 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 coating solution for a conductive layer containing the above-mentioned materials and solvent, forming a coating film from the coating solution, and drying the coating film. Examples of the solvent 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 contain a compound having a perovskite structure (perovskite compound).

[0044] The perovskite compound preferably has an organic-inorganic hybrid structure in which an organic compound and an inorganic compound are components of the perovskite 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, R is an organic molecule, and C l N m H n (l, m, n are all positive integers).

[0047] Specific examples of R include 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 ions thereof (e.g., methylammonium (CHNH)), phenethylammonium, etc. Among these, methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, and ions thereof, and phenethylammonium are preferred, and methylamine, ethylamine, propylamine, and ions thereof are more preferred.

[0048] In the general formula RM-X3, M is a metal atom, such as 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 alone 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 halogen in the structure makes the organic-inorganic perovskite compound soluble in organic solvents, enabling application to inexpensive printing methods, etc. Furthermore, iodine is more preferred because it narrows the energy band gap of the organic-inorganic perovskite compound.

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

[0051] The organic-inorganic perovskite compound is preferably a crystalline semiconductor. When the organic-inorganic perovskite compound is a crystalline semiconductor, the electron mobility increases and the photoelectric conversion efficiency improves. Note that a crystalline semiconductor refers to a semiconductor from which a scattering peak can be detected by X-ray diffraction measurement or the like.

[0052] The thickness of the organic-inorganic perovskite compound portion may be 5 nm or more and 5,000 nm or less. If it is 5 nm or more, the amount of light absorption increases, further increasing the photoelectric conversion efficiency. If it is 5,000 nm or less, the occurrence of regions with low charge separation efficiency can be reduced, leading to improved photoelectric conversion efficiency.

[0053] The thickness of the perovskite compound portion is more preferably 10 nm or more and 1000 nm or less, and even more preferably 20 nm or more and 500 nm or less.

[0054] The active layer can be formed by preparing a conductive layer coating solution containing the above-mentioned materials and solvent, forming a coating film from this, 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 liquids with different compositions.

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

[0056] The reflective layer is formed by stacking, for example, a first electrode, a charge transport layer, a photoelectric conversion layer, a reflective layer, and a second electrode in this order, and by reflecting light that has not been absorbed by the photoelectric conversion layer, it promotes light absorption in the perovskite layer again, thereby improving the light absorption efficiency of the entire element.

[0057] In order to make the light reflected by the reflective layer easily absorbed by the photoelectric conversion layer, the reflective layer contains particles having a volume average particle size of 50 nm to 600 nm. The particle size of the particles contained 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 composed of a conductive material. Examples of conductive materials include metal oxides, metal-based materials such as aluminum, palladium, iron, copper, and silver, and composite materials surface-treated by electrolysis, spray coating, or mixing. Among these, metal oxides are preferred, and metal oxides are more preferred. The metal oxide is preferably any one selected from tin oxide, zinc oxide, and titanium oxide. These metal oxides can further contribute to improving current density by imparting an oxygen deficiency structure through appropriate reduction or 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: Particles to be measured were observed using a scanning electron microscope S-4800 manufactured by Hitachi, Ltd., and the major axis diameter and minor axis diameter of each of 100 particles were measured from the images obtained by the observation, and the arithmetic mean thereof was calculated.

[0062] In this embodiment, the refractive index of particles is defined as a value measured using Cargill standard refractive index liquid manufactured by CARGILLE. The specific measurement method is as follows: Particles are placed on a glass slide and refractive index liquid is dropped onto the slide. The particles and refractive index liquid are mixed well and irradiated from below with a sodium lamp. The outline of the particles is observed from above, and if the outline cannot be seen, the refractive index of the refractive index liquid and the particles is deemed to be equal. In addition, for resins formed into films, the refractive index is defined as a value measured according to JIS K7142 Plastics - Determination of refractive index.

[0063] The refractive index of the resin film is defined as a value measured using an Abbe refractometer DR-A1 (trade name, manufactured by Atago Co., Ltd.).

[0064] The reflective layer according to this embodiment may contain a binder material in addition to the 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 into a dense and uniform film, the interface between the reflective layer and the active layer is formed uniformly, and the electron transport ability is improved. On the other hand, if an excessive amount of binder resin is contained, the electron transport ability within the reflective layer may be reduced.

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

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

[0067] The reflective layer can be formed by preparing a coating solution for the reflective layer containing the above-mentioned materials and solvent, forming a coating film from this, 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. Examples of dispersion methods for dispersing particles in the coating solution for the reflective layer include methods using a paint shaker, a sand mill, a ball mill, and a liquid collision-type high-speed disperser. The conductive layer coating solution prepared by dispersion may be filtered to remove impurities as the coating solution for the reflective layer.

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

[0069] Second Embodiment (Reference Embodiment) As a result of investigations, the inventors have found that in a photoelectric conversion element having, in this order, an anode, a first layer containing a perovskite compound, a conductive second layer, and a cathode, the photoelectric conversion efficiency can be improved by having the second layer contain conductive particles in which core particles are coated with a conductive material.

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

[0071] The second embodiment of the present invention will be described in detail below. Note that the present invention is not limited to the following embodiment, and appropriate modifications and improvements to the following embodiment based on the ordinary knowledge of those skilled in the art are also included in the scope of the present invention, provided that they do not deviate from the spirit of the present invention.

[0072] FIG. 3 is a schematic cross-sectional view of one embodiment of the photoelectric conversion element of this embodiment. FIG. 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. A current flows between the anode 102 and the cathode 106 through an external circuit. The first layer 104 is a photoelectric conversion layer, or active layer, that is excited by light captured 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. The charge transport layer 103 is present between the first layer 104 and the two electrodes 102 and 106, but is not necessarily an essential component of the photoelectric conversion element. The first layer 104 can also be formed in a tandem structure consisting of multiple layers. 3, the anode 102 is disposed on the substrate 101 side, but the cathode 106 may be disposed 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 laminated in this order. Hereinafter, 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 a coating solution for each layer described below, coating the layers in the desired order, and drying them. Examples of the coating method for the coating solution include dip coating, spray coating, inkjet coating, roll coating, die coating, blade coating, curtain coating, wire bar coating, ring coating, and spin coater coating.

[0074] <substrate> The substrate 101 is preferably made of a material that can form an electrode (anode 102 in the case of FIG. 3) on its main surface and that will not be chemically altered when a functional layer that constitutes the photoelectric conversion element is formed. Examples of substrate materials include glass, plastic, polymer film, and silicon. When light is taken in from the substrate 101 side, a transparent material is used for the substrate 101.

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

[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 FIG. 3) so that the photoelectric conversion element can function effectively. When light is taken in from the side opposite to the substrate 101 (cathode 106 in FIG. 3), the electrode on the side opposite to the substrate 101 (cathode 106 in FIG. 3) is formed from a highly transparent material.

[0077] Examples of transparent or semitransparent electrode materials include conductive metal oxides, metals, etc. If these materials are not transparent, they can be made into a thin film with a thickness that allows light to pass through, thereby forming a transparent or semitransparent electrode. Specific examples of transparent or semitransparent electrode materials include indium oxide, zinc oxide, tin oxide, and composites thereof such as ITO, IZO, FTO, and NESA, as well as gold, platinum, silver, copper, and aluminum.

[0078] There is no limitation on the method for forming the electrodes 102 and 106, and they can be formed by, for example, vacuum deposition, sputtering, ion plating, plating, coating, or the like.

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

[0080] The hole transport layer 103 has a function of transporting holes from the active layer 104 to the anode 102. It also has a function of preventing electrons from flowing from the active layer 104 to the anode 102, thereby preventing a decrease in photoelectric conversion efficiency due to recombination of electrons and holes. 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 such as C or Si to form a tetrahedral structure; aromatic amine compounds such as triarylamine; triphenylene compounds; nitrogen-containing heterocyclic compounds; and liquid crystalline cyano compounds.

[0082] Specific examples include 2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9-spirobifluorene (also referred to as Spiro-OMeTAD), poly(3-hexylthiophene-2,5-diyl), 4-(diethylamino)benzaldehyde 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 solvent, forming a coating film of the coating solution, and drying the coating film. Examples of the solvent 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 structure (perovskite compound). The perovskite compound is preferably an organic-inorganic perovskite compound having an organic-inorganic hybrid structure in which an organic compound and an inorganic compound are components of the perovskite 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 ions thereof. M is a metal atom, such as Cu, Ni, Mn, Fe, Co, Pd, Ge, Sn, Pb, and Eu. These metal atoms may be used alone or in combination of two or more. X is a halogen atom, such as chlorine, bromine, iodine, and fluorine. These halogen atoms may be used alone or in combination of two or more.

[0087] The organic-inorganic perovskite compound is preferably a crystalline semiconductor. When the organic-inorganic perovskite compound is a crystalline semiconductor, the electron mobility increases and the photoelectric conversion efficiency improves. Note that a crystalline semiconductor refers to a semiconductor from which a scattering peak can be detected by X-ray diffraction measurement or the like.

[0088] 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 solvent and a material that forms a perovskite compound through a chemical reaction, forming a coating film of the coating solution, and drying the coating solution. 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 particles with a conductive material. The core particles and the conductive material forming the coating layer have different compositions or materials.

[0091] In this embodiment, examples of the conductive material that forms the coating layer of the conductive particles include metal oxides, metal-based materials such as aluminum, palladium, iron, copper, and silver; composite materials surface-treated by electrolysis, spray coating, or mixing and 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 any one selected from tin oxide, zinc oxide, and titanium oxide.

[0092] Furthermore, the metal oxides can further contribute to improving the current density by being given an oxygen deficiency structure through appropriate reduction or by being appropriately doped. When tin oxide is used, it is preferably doped with any element selected from niobium, tantalum, phosphorus, tungsten, and fluorine. When zinc oxide is used, it is preferably doped with any element selected from aluminum and gallium. When titanium oxide is used, it is preferably doped with any element selected from niobium and tantalum.

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

[0094] In this embodiment, examples of materials constituting the core 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] The core particles can be of various shapes, such as spherical, polyhedral, ellipsoidal, flaky, and needle-like. Among these, from the viewpoint of electron injection at the interface between the active layer and the conductive layer, it is preferable to use core particles of spherical, polyhedral, or ellipsoidal shapes. Furthermore, it is more preferable that the core particles be spherical or polyhedral close to spherical.

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

[0097] Furthermore, the average major axis diameter a and the average minor axis diameter b of the conductive particles are preferably both 50 nm or more and 600 nm or less. If the average major axis diameter a and the average minor axis diameter b are 50 nm or more, re-aggregation of the conductive particles is less likely to occur after the coating liquid for the conductive layer is prepared. If the average major axis diameter a and the average minor axis diameter b are 600 nm or less, the surface of the conductive layer 105 is less likely to become rough. If the surface of the conductive layer 105 becomes rough, leaks are more likely to occur. Furthermore, in this embodiment, the average major axis diameter a and the average minor axis diameter b of the conductive particles are more preferably 50 nm or more and 400 nm or less.

[0098] In this embodiment, the average major axis diameter a and the 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 each of 100 conductive particles were measured from an image obtained by observing the conductive particles to be measured using a scanning electron microscope "S-4800" manufactured by Hitachi, Ltd., and the arithmetic mean thereof was calculated.

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

[0100] The conductive layer according to this embodiment may be formed solely of the conductive particles, or may 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, the conductive layer 105 preferably contains 20% by volume or more of the conductive particles. If the conductive particle content is less than 20% by volume, the distance between the conductive particles increases, which tends to reduce the current density. Therefore, when the conductive layer 105 is formed of conductive particles and a binder resin, the binder resin content in the conductive layer 105 is 80% by volume or less.

[0101] 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 conductive layer coating liquid containing the conductive particles, a solvent, and, if necessary, the binder resin, forming a coating film of the coating liquid, and drying the coating liquid. Examples of solvents used in the coating liquid include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Examples of dispersion methods for dispersing the conductive particles in the conductive layer coating liquid include methods using a paint shaker, a sand mill, a ball mill, and a liquid collision-type high-speed disperser. The conductive layer coating liquid prepared by dispersion may be filtered to remove unnecessary components.

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

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

[0105] Although the detailed mechanism by which this embodiment achieves its effects is unclear, it is presumed as follows. It is believed that the photoelectric conversion efficiency is improved by the second layer containing an electron transport compound having any of the configurations of this embodiment due to two effects. One is believed to be due to improved electron extraction by the electron transport compound. It is believed that matching the levels of the perovskite compound and the electron transport compound allows for rapid electron transfer, thereby improving the photoelectric conversion efficiency. The other is believed to be due to the promotion of the formation of the first layer, in which the second layer is laminated as an underlayer, thereby improving the crystallinity of the first layer. It is believed that the configuration of the second layer according to this embodiment facilitates the formation of an interface, and the surface wettability is high, which is compatible with the first layer, promoting crystal growth. It is believed that the improved crystallinity of the first layer improves light absorption, allowing generated charges to move efficiently, thereby improving the photoelectric conversion efficiency.

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

[0107] FIG. 4 is a schematic diagram showing an example of the configuration of a photoelectric conversion element according to this embodiment. FIG. 4(A) is a plan view seen from the cathode side, FIG. 4(B) is a cross-sectional view taken along line a-a' of FIG. 4(A), and FIG. 4(C) is a cross-sectional view taken along line b-b' of FIG. 4(A). The photoelectric conversion element of FIG. 4 includes an anode 211, a third layer 212, a first layer 213, a second layer 214, and a cathode 215 stacked in this order on a substrate 216, and a 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 a current between the anode 211 and the cathode 215. The third layer 212 is a layer that exists between the first layer 213 and the anode 211, and is not necessarily an essential layer. The first layer 213 may have a plurality of layers to form a tandem structure.

[0108] The photoelectric conversion element of this embodiment can be manufactured, for example, by preparing a coating solution for each layer described below, coating the layers in the desired order, and then drying the coating solution. In this case, the coating solution can be applied by dip coating, spray coating, inkjet coating, dispense coating, roll coating, die coating, blade coating, curtain coating, wire bar coating, ring coating, spin coater coating, or the like.

[0109] <Board 216> A substrate that can form electrodes on its main surface and is made of a material that will not be chemically changed when functional layers that constitute the photoelectric conversion element are formed is preferably used as the substrate 216. Examples of materials for the support substrate include glass, plastic, polymer film, and silicon.

[0110] <Electrodes (anode 211, cathode 215)> The electrodes are made of a conductive material. Examples of materials that can be used for the electrodes include inorganic compounds such as metals and metal oxides, and organic compounds such as conductive polymers. The electrodes may be in the form of a single layer or a laminate of multiple layers.

[0111] In the photoelectric conversion element of this embodiment, light incident from the electrodes is absorbed by the perovskite compound contained in the first layer 213, thereby generating electrons and holes. The generated electrons reach the cathode 215, and the generated holes reach the anode 211, and are extracted as electrical energy (current) outside the photoelectric conversion element. For the photoelectric conversion element to function effectively, incident light must pass through the substrate 216 and reach the first layer 213, so highly transparent materials are preferably used for the substrate 216 and the electrodes. In the case of a photoelectric conversion element configured to capture light from the substrate 216 side, highly optically transparent materials are preferably used for the substrate 216 and the electrodes on the substrate 216. In the case of a photoelectric conversion element configured to capture light from the electrode side farther from the substrate 216, highly optically transparent materials are preferably used for the electrode farther from the substrate 216.

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

[0113] There is no limitation on the method for forming the electrodes, and they can be formed by, for example, vacuum deposition, sputtering, ion plating, plating, coating, or the like.

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

[0116] Examples of hole transport materials for 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 such as C or Si to form a tetrahedral structure, aromatic amine compounds such as triarylamine, triphenylene compounds, nitrogen-containing heterocyclic compounds, and liquid crystalline cyano compounds.Specific 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)benzaldehyde diphenylhydrazone, and polyethylenedioxythiophene (PEDOT).

[0117] Additionally, an additive 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 solvent, forming a coating film of this, 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 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 an organic compound and an inorganic compound are components of the perovskite 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 ions thereof.

[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 alone or in combination of two or more.

[0125] In the general formula RMX3, X is a halogen atom, examples of which include chlorine, bromine, iodine, fluorine, etc. These halogen atoms may be used alone or in combination of two or more.

[0126] The organic-inorganic perovskite compound is preferably a crystalline semiconductor. When the organic-inorganic perovskite compound is a crystalline semiconductor, the electron mobility increases and the photoelectric conversion efficiency improves. Note that a crystalline semiconductor refers to a semiconductor from which a scattering peak can be detected by X-ray diffraction measurement or the like.

[0127] The thickness of the organic-inorganic perovskite compound portion 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 conductive layer coating solution containing the above-mentioned materials and solvent, forming a coating film from this, 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 of the materials of the first layer 213 and improving crystallinity.

[0129] <Second Layer 214> The photoelectric conversion element according to this embodiment has a second layer 214 between a first layer 213 and a 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, and an electron transporting compound is bonded to the polymer compound.

[0131] Examples of the electron transport compound contained 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 bathocuproine, naphthalenetetracarboxylic acid diimide and its derivatives, perylenetetracarboxylic acid diimide and its derivatives, pyromellitic acid diimide and its derivatives, etc. Among these, naphthalenetetracarboxylic acid diimide and its derivatives, perylenetetracarboxylic acid diimide and its derivatives, and pyromellitic acid diimide and its derivatives are preferable.

[0132] The second layer 214 may be a cured film formed by curing a curable resin, and the electron transporting compound may be bonded to a resin chain 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 of the structures represented by formulas (E-1) to (E-3) and at least one of the structures represented by formulas (P-1) to (P-5). The second layer 214 is a layer (cured layer) having at least one of the structures represented by formulas (E-1) to (E-3) and at least one of the structures represented by formulas (P-1) to (P-5). In other words, the second layer 214 contains a cured film (polymer) having at least one of the structures represented by formulas (E-1) to (E-3) and at least one of the structures 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 R 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. 101 ~R 106 One or two of R 201 ~R 210 One or two of R 301 ~R 304One or two of the groups represent a single bond. Substituents for the substituted alkyl group include an alkyl group, an aryl group, a halogen atom, and a carbonyl group. Substituents for the substituted aryl group or substituted heterocyclic group include a halogen atom, a nitro group, a cyano group, an alkyl group, a halogen-substituted alkyl group, an alkoxy group, and a carbonyl group.

[0136] [ka]

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

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

[0139] Specific examples of formulas (E-1) to (E-3) are shown in Tables 1 to 5. In Tables 1 to 5, the bonding sites are indicated by dashed lines. The specific examples shown in Tables 1 to 5 are the same as the specific examples E-1 to E-3 shown by the corresponding numbers in Tables 6 to 11 or Tables 12 to 19. 1 Therefore, in Tables 1 to 5, the same structure may be shown multiple times.

[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 a polymerizable functional group reactive with the crosslinking agent, and an electron transport compound having a polymerizable functional group reactive with the crosslinking agent are dissolved in a solvent to prepare a coating liquid. A coating film of this coating liquid is formed and thermally cured to obtain the second layer 214. The thermal curing is preferably carried out while the coating film is drying, as this allows for a more uniform reaction.

[0146] [Electron transport compound] The electron transporting compound is preferably a naphthyltetracarboxydiimide derivative, a perylenetetracarboxydiimide derivative, or a pyromellitic diimide derivative. The electron transporting compound preferably has a polymerizable functional group capable of reacting with a crosslinking agent. Examples of the polymerizable functional group include a hydroxyl group, a thiol group, a carboxyl group, an amino group, an isocyanate group, and an acrylic group.

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

[0148] Furthermore, in order to have polymerizable functional groups (e.g., hydroxyl groups, thiol groups, amino groups, and carboxyl groups) that can react with a crosslinking agent, methods include, for example, directly introducing polymerizable functional groups into a derivative having the structure (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. Examples of the latter method include, for example, a method of introducing a functional group-containing aryl group using a cross-coupling reaction using a palladium catalyst and a base based on a halide of a naphthyltetracarboxydiimide derivative, a method of introducing a functional group-containing alkyl group using a cross-coupling reaction using an FeCl3 catalyst and a base, and a method of introducing a hydroxyalkyl group or a carboxyl group by reacting an epoxy compound or CO2 after lithiation. Examples of the former method include, for example, a method of using a naphthalenetetracarboxylic dianhydride derivative or a 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 a naphthyltetracarboxydiimide derivative.

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

[0150] Methods for introducing these polymerizable functional groups into derivatives having the structure (E-2) or (E-3) include a method for directly introducing the polymerizable functional group and a method for introducing a structure having a polymerizable functional group or a functional group that can serve as a precursor of a polymerizable functional group. Examples of the latter method include a method using a cross-coupling reaction using a palladium catalyst and a base based on a halide of a perylene tetracarboxydiimide derivative or a pyromellitic diimide derivative, and a method using a cross-coupling reaction using an FeCl catalyst and a base. Examples of the former method include a method using a perylene tetracarboxylic dianhydride derivative or a monoamine derivative having a polymerizable functional group or a functional group that can serve as a precursor of a polymerizable functional group as a raw material for synthesizing a perylene imide derivative.

[0151] Next, examples of the electron transporting compound having a polymerizable functional group are given below.

[0152] [ka]

[0153] [ka]

[0154] [ka]

[0155] [ka]

[0156] [ka]

[0157] [ka]

[0158] [ka]

[0159] [ka]

[0160] [ka]

[0161] [ka]

[0162] [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 independently represents a substituted or unsubstituted alkylene group having 1 to 10 atoms in the main chain, or a substituted or unsubstituted phenylene group.

[0165] R 2represents a single bond, a substituted or unsubstituted alkylene group having 1 to 10 atoms in the main chain, or a substituted or unsubstituted phenylene group. 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 of the groups represented by formulae (A-1) to (A-6).

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

[0169] D 1 is a group represented by formula (D) having 5 to 15 atoms in the main chain. From the viewpoint of improving photoelectric conversion efficiency, it is more preferably a group represented by formula (D) having 10 to 15 atoms in the main chain. 1 In formula (D), the number of atoms in the main chain refers to the shortest number of atoms between the rightmost and leftmost bonds. For example, a p-phenylene group has 4 atoms in its main chain. An m-phenylene group has 3 atoms in its main chain. An o-phenylene group has 2 atoms in its main chain.

[0170] E 1 is represented by any one of the following formulas (E-1) to (E-3): Ru base is.

[0171] Here, E in formulas (U1) and (U2) 1 The right side of 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 a substituted or unsubstituted alkyl group is O, S, NH, or NR 16 (R 16is an alkyl group.) may be substituted. The substituent of the substituted aryl group may be an alkyl group, a halogen atom, a nitro group, or a cyano group. The substituent of the substituted alkyl group may be an alkyl group, an aryl group, a halogen atom, a nitro group, or a cyano group. In the case of a bonding site, E may be bonded to the structures represented by formulas (U1) and (U2) via a substituted or unsubstituted arylene group or a substituted or unsubstituted alkylene group. 1 Except for D 1 indicates that it is bound to

[0172] [ka]

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

[0174] [ka]

[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 is O, S, NH, or NR 15 (R 15 is an alkyl group.

[0176] R 2represents a single bond, a substituted or unsubstituted alkylene group having 1 to 10 atoms in the main chain, or a substituted or unsubstituted phenylene group. 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 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.

[0179] A 1 and A 2 represents any of the groups represented by formulae (A-1) to (A-5).

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

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

[0182] The arrow indicates R 3 It refers to the side that binds to the

[0183] E in (B-2) 1 The right side of represents a hydrogen atom, a substituted or unsubstituted aryl group, an alkyl group, a heterocyclic group, or a bonding site. Substituents for the substituted aryl group include an alkyl group, a halogen atom, and a nitro group. In the case of a bonding site, E is bonded to the structures represented by formulas (U1) and (U2) via a substituted or unsubstituted arylene group or an alkylene group. 1 Except for D 1In formula (B-3), the right side of CH2 indicates that it is bonded to a side chain of the resin present in the second layer 214.

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

[0185] [ka]

[0186] In formula (D), R 4 , R 5 , 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 is O, S, NH, or NR 15 (R 15 is an alkyl group. 4 , R 5 , R 6 and R 7and are each 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.

[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 is more preferably an unsubstituted phenylene group.

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

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

[0190] [ka]

[0191] In formulas (E-1) to (E-3), R 101 ~R 106 , R 201 ~R 210 , R 301 ~R 304 R 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. 101 ~R 106 1 of 1, R 201 ~R 210 1 of 1, R 301 ~R 304 1 of One, and a single bond. Substituents for the substituted alkyl group include an alkyl group, an aryl group, a halogen atom, and a carbonyl group. Substituents for the substituted aryl group or the substituted heterocyclic group include a halogen atom, a nitro group, a cyano group, an alkyl group, a halogen-substituted alkyl group, an alkoxy group, and a carbonyl group.

[0192] In the structure represented by formula (U1), R 2 is bonded to structure X surrounded by a dashed line in the following formula. This structure X is considered to be the part corresponding to the resin chain. The same can be said for formula (U2).

[0193] [ka]

[0194] The present inventors believe that the photoelectric conversion efficiency is improved due to two effects of the second layer 214 having the structures represented by formulas (U1) and (U2). 1 This is thought to be because the electron-withdrawing effect is improved by the urethane bond. Not only the electron-transporting compound but also the urethane bond has electron-withdrawing properties. Therefore, it is thought that the rapid electron transfer from the perovskite compound improves the photoelectric conversion efficiency. Another reason is thought to be that the formation of the first layer 213, which is laminated with the second layer 214 as a base layer, is promoted, improving the crystallinity of the first layer 213. It is thought that the second layer 214 having this structure makes it easy to form an interface, and the surface wettability is high, which is compatible with the first layer 213, promoting crystal growth. It is thought that the improved crystallinity of the first layer 213 improves light absorption, allowing the generated charges to move efficiently, thereby improving the photoelectric conversion efficiency.

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

[0196] The content of the structures represented by formulas (U1) and (U2) in the second layer 214 can be analyzed by a general analytical method. An example of the analytical method is shown below. The content of the structure represented by formula (U1) in the underlayer is measured using FT-IR and the KBr-tab method. The content of the structure represented by formula (U1) in the second layer 214 can be calculated by creating a calibration curve based on the absorption due to the isocyanurate structure using samples in which the amount of tris(2-hydroxyethyl) isocyanurate added to KBr powder is changed. The same can be considered for formula (U2).

[0197] Furthermore, the structures represented by formulas (U1) and (U2) are solid with respect to the second layer 214. 13 This can be confirmed by measurement methods such as C-NMR measurement, mass spectrometry measurement, MS spectrum measurement by pyrolysis GC analysis, and characteristic absorption measurement by infrared spectroscopy. 13 C-NMR measurements were performed using a Chemagnetics CMX-300Infiniy. 13 The measurement conditions were: C, standard substance: polydimethylsiloxane, number of accumulations: 8192, pulse sequence: 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 was performed using a mass spectrometer (MALDI-TOF MS: Bruker Daltonics Ultraflex) under the following conditions: acceleration voltage: 20 kV, mode: Reflector, molecular weight standard: fullerene C60. The molecular weight was measured and confirmed by the peak top value obtained.

[0198] In addition to the structures represented by formulae (U1) and (U2), the second layer 214 may contain various resins, crosslinking agents, organic particles, inorganic particles, metal oxide particles, leveling agents, catalysts for curing promotion, and the like, in order to improve film-forming properties and photoelectric conversion efficiency. However, the content of these ingredients is preferably less than 50 mass % and more preferably less than 20 mass % with respect to the total mass of the second layer 214. Furthermore, the film thickness of the second layer 214 is preferably 10 nm or more and 1.0 μm or less.

[0199] Specific examples of the structures represented by formulae (U1) and (U2) are shown below, but the present invention is not limited to these. In Tables 6 to 11, the bond site is indicated by a dashed line. Furthermore, a single bond is indicated as "single." Furthermore, the left-right orientation of formulae (U1) and (U2) is the same as the left-right orientation of each structure in Tables 6 to 11. Furthermore, in the exemplary compounds in Tables 6 to 11, R in formulae (U1) and (U2) 9 , R 12 are all hydrogen atoms. 6 ,R 7 ,Ar 2 ,A 2 ,o,p,q are respectively,D 1 Inside, R 6 ,R 7 ,Ar 2 ,A 2 , o, p, q. E in equations (U1) and (U2) 1 Specific examples are shown in Tables 1 to 5 with 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 a polymerizable functional group capable of reacting with the isocyanate group of the isocyanate compound, and an electron transport compound having a polymerizable functional group capable of reacting with the isocyanate group of the isocyanate compound are dissolved in a solvent to prepare a coating liquid. A coating film of this coating liquid is formed and thermally cured to obtain the second layer 214. The thermal curing is preferably carried out while the coating film is drying, as this allows for a more uniform reaction.

[0207] [Isocyanate Compound] The isocyanate compound is preferably an isocyanate compound in which the isocyanate group is protected with a blocking agent such as oxime (blocked isocyanate compound). When the blocked isocyanate compound is heated together with the resin and the electron transport compound, an addition reaction begins, and the blocking agent is removed, allowing the crosslinking reaction to proceed. A cured product having a structure represented by formula (U1) and (U2) is 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, acetaldoxime, 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 alone or in combination of two or more. Among these blocking agents, from the viewpoints of versatility, ease of production, workability, and heat curing temperature, oxime-based compounds such as methyl ethyl ketoxime, lactam-based compounds such as ε-caprolactam, and imidazole-based compounds such as 2-methylimidazole are preferred.

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

[0210] [ka]

[0211] [ka]

[0212] The isocyanate group of the isocyanate compound (number of moles = I) is preferably present in the isocyanate compound at 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 preferred because it improves the reaction efficiency between the isocyanate group and the polymerizable functional group and increases the crosslink density.

[0213] [Electron transport compound] Details of the electron transporting compound having a polymerizable functional group capable of reacting with an isocyanate group are as described above in [Electron transporting compound] in [Second photoelectric conversion element].

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

[0215] It is preferable that the cured product having the structure represented by formula (U1) and (U2) further has the structure represented by formula (2) below. That is, it is preferable that the resin has the structure represented by formula (2) below. When the second layer 214 has the structure represented by formula (2), the adhesion between the lower and upper layers of the second layer 214 and the thickness uniformity of the second layer 214 are improved, leading to an improvement in photoelectric conversion efficiency.

[0216] [ka]

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

[0218] 〔solvent〕 The solvent for preparing the coating liquid for forming the second layer 214 can be selected from, for example, alcohols, aromatics, halogenated hydrocarbons, ketones, ketone alcohols, ethers, esters, etc. More specifically, organic solvents such as methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, 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 alone or in combination of two or more.

[0219] [Confirmation of curability] The curability of the second layer 214 can be confirmed, for example, as follows. A coating film of a coating liquid for forming the second layer 214, which contains an isocyanate compound, a resin, and an electron transport substance, is formed on an aluminum sheet using a Mayer bar, and the coating film is dried by heating at 160°C for 40 minutes to form the second layer 214. The resulting second layer 214 is immersed in a mixed solvent of cyclohexanone / ethyl acetate = 1 / 1 for 2 minutes, and then dried at 160°C for 5 minutes. The mass of the second layer 214 before and after immersion is confirmed to ensure 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 are each independently a hydrogen atom, a methylene group, or -CHOR 2 (R 2 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. R represents a monovalent group represented by the formula (i), a group represented by the formula (ii), or a group represented by the formula (ii). 11 ~R 16 At least one of R 22 ~R 25 at least one of R is a group represented by formula (i), 11 ~R 16 At least one of R 22 ~R 25 At least one of the groups is a group represented by formula (ii).

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

[0224] [ka]

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

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

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

[0228] * represents the side that is bonded to N in formula (C1) or N in formula (C2).

[0229] [ka]

[0230] [ka]

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

[0232] α represents an alkylene group having 1 to 6 atoms in the main chain, an alkylene group having 1 to 6 atoms in the main chain substituted with an alkyl group having 1 to 6 carbon atoms, an alkylene group having 1 to 6 atoms in the main chain substituted with a benzyl group, an alkylene group having 1 to 6 atoms in the main chain substituted with an alkoxycarbonyl group, or an alkylene group having 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. α may be replaced by ). α is preferably 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 an alkyl group having 1 to 4 carbon atoms.

[0233] β represents a phenylene group, a phenylene group substituted with an alkyl 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 having 1 to 6 atoms in the main chain, or an alkylene group having 1 to 6 atoms in the main chain substituted with an alkyl group having 1 to 6 carbon atoms. γ is preferably 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 an alkyl group having 1 to 4 carbon atoms.

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

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

[0237] * represents the side that is bonded to N in formula (C1) or N in formula (C2).

[0238] E in formula (ii) 1 When the number of atoms in the main chain other than E is 12 or less, the distance between the triazine ring and the electron transporting moiety is appropriate, and therefore smooth electron transport properties are exhibited due to interaction, which is preferable in terms of improving photoelectric conversion efficiency. 1 The number of atoms in the main chain other than the above is 2 to 9.

[0239] [ka]

[0240] In formulas (E-1) to (E-3), R 101 ~R 106 , R 201 ~R 210 , R 301 ~R 304 R 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. 101 ~R 106 One or two of R 201 ~R 210 One or two of R 301 ~R 304 One or two of the groups represent a single bond. Substituents for the substituted alkyl group include an alkyl group, an aryl group, a halogen atom, and a carbonyl group. Substituents for the substituted aryl group or substituted heterocyclic group include a halogen atom, a nitro group, a cyano group, an alkyl group, a halogen-substituted alkyl group, an alkoxy group, and a carbonyl group.

[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 a melamine compound or the moiety derived from a guanamine compound is bonded to a group represented by formula (i) and a group represented by formula (ii). The group represented by formula (i) is a moiety derived from a resin. The group represented by formula (ii) has an electron transport moiety represented by any one of (E-1) to (E-3).

[0242] The present inventors believe that the photoelectric conversion efficiency is improved due to two effects of the second layer 214 having the structures represented by formulas (C1) and (C2). 1 ) with the structures represented by formulas (C1) and (C2), improving the electron-withdrawing effect. The melamine compound and the guanamine compound have a triazine ring structure, and the triazine ring has electron deficiency as a property of the triazine ring. The coexistence of the electron-transporting compound and the triazine ring is thought to facilitate electron transfer from the perovskite compound, improving the photoelectric conversion efficiency. Another reason is thought to be that the formation of the first layer 213, in which the second layer 214 is laminated as an underlayer, is promoted, improving the crystallinity of the first layer 213. The second layer 214 has this structure, which is thought to facilitate the formation of an interface and to have high surface wettability with the first layer 213, promoting crystal growth. The improved crystallinity of the first layer 213 is thought to improve light absorption, allowing the generated charges to move efficiently, improving the photoelectric conversion efficiency.

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

[0244] [ka]

[0245] The second layer 214 preferably contains the structure represented by formula (C1) or the structure represented by formula (C2) in an amount of 30% by mass or more and 100% by mass or less based on 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 by a general analytical method. An example of the analytical method is shown below. The content of the structure represented by formula (C1) or (C2) is measured using FT-IR and the KBr-tab method. The content of the structure represented by formula (C1) or (C2) in the second layer 214 can be calculated by creating a calibration curve based on the absorption due to the triazine ring using samples in which the amount of melamine or guanamine added to KBr powder is changed.

[0247] Furthermore, the structure represented by formula (C1) or (C2) is a solid 13 This can be confirmed by measurement methods such as C-NMR measurement, mass spectrometry measurement, MS spectrum measurement by pyrolysis GC analysis, and characteristic absorption measurement by infrared spectroscopy. 13 C-NMR measurements were performed using a Chemagnetics CMX-300Infiniy. 13 The measurement conditions were: C, standard substance: polydimethylsiloxane, number of accumulations: 8192, pulse sequence: 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 analysis was performed using a mass spectrometer (MALDI-TOF MS: Bruker Daltonics Ultraflex) under the following conditions: acceleration voltage: 20 kV, mode: Reflector, molecular weight standard: fullerene C60. The molecular weight was measured and confirmed by the peak top value obtained.

[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 promotion, etc., in order to improve film-forming properties and photoelectric conversion efficiency. However, the content of these ingredients is preferably less than 50 mass % and more preferably less than 20 mass % with respect to the total mass of the second layer 214. Furthermore, the film thickness of the second layer 214 is preferably 10 nm or more and 1.0 μm or less.

[0249] Specific examples of the structure represented by formula (C1) or (C2) are shown below, but the present invention is not limited to these. In each specific example, in formula (ii), the electron transporting moiety E 1 The number of atoms in the main chain other than E is shown. In Tables 12 to 19, the bond site is shown with a dashed line. A single bond is indicated as "single." The left-right direction of the group represented by formula (i) and the group represented by formula (ii) is the same as the left-right direction of each structure in Tables 12 to 19. E in formula (ii) 1 Specific examples are shown in Tables 1 to 5 with 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 liquid containing a melamine compound or a guanamine compound, a resin having a polymerizable functional group capable of reacting with these compounds, and an electron transport compound having a polymerizable functional group capable of reacting with these compounds is applied to form a coating film. The resulting coating film is then thermally cured to obtain the second layer 214.

[0259] [Melamine compounds, guanamine compounds] Melamine compounds and guanamine compounds will now be explained. Melamine compounds or guanamine compounds are synthesized by a known method using, for example, melamine or guanamine and formaldehyde.

[0260] Specific examples of melamine compounds and guanamine compounds are shown below. The specific examples below show monomers, but they may also contain oligomers (polymers) of the monomers. From the viewpoint of improving conversion efficiency, it is preferable that the monomers are contained in an amount of 10% by mass or more based on the total mass of the monomers and polymers. The degree of polymerization of the polymers is preferably 2 or more and 100 or less. Two or more types of polymers and monomers can be mixed and used. Examples of commonly available melamine compounds include Super Melami No. 90 (manufactured by Nippon Oil & Fats Corporation), Super Beckamin® TD-139-60, L-105-60, L127-60, L110-60, J-820-60, and G-821-60 (manufactured by DIC Corporation), Yuvan 2020 (Mitsui Chemicals), Sumitex Resin M-3 (Sumitomo Chemical Co., Ltd.), and Nikalac MW-30, MW-390, and MX-750LM (manufactured by Nippon Carbide Corporation). Examples of commonly available guanamine compounds include Super Beckamin® L-148-55, 13-535, L-145-60, and TD-126 (manufactured by DIC Corporation), and Nikalac BL-60 and BX-4000 (manufactured by Nippon Carbide Corporation).

[0261] Specific examples of melamine compounds are shown below.

[0262] [ka]

[0263] [ka]

[0264] Specific examples of guanamine compounds are shown below.

[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 functional groups (number of moles = H) of the polymerizable functional groups of the resin and electron transport compound (a compound having a structure represented by any one of (E-1) to (E-3)) is preferably 1:0.5 to 1:3.0. A molar ratio within this range is preferred because it increases the proportion of functional groups that react.

[0269] [Electron transport compound] The electron transport compound having a polymerizable functional group capable of reacting with a melamine compound or a guanamine compound is described in detail in the section [Electron Transport Compound] in the section [Second Photoelectric Conversion Element] above. The electron transport compound is represented by the formula (ii) E 1 It comes from the structure shown below.

[0270] 〔resin〕 A resin having a polymerizable functional group capable of reacting with a melamine compound or a guanamine compound will now be described. The resin has a group represented by formula (i). This resin can be obtained by polymerizing a monomer having a polymerizable functional group (hydroxyl group, thiol group, amino group, carboxyl group, or methoxy group), which can be purchased from, for example, Sigma-Aldrich Japan K.K. or Tokyo Chemical Industry Co., Ltd.

[0271] In addition, resins can be generally purchased. Examples of commercially available resins include polyether polyol resins such as AQD-457 and AQD-473 manufactured by Nippon Polyurethane Industry Co., Ltd. and Sannix GP-400 and GP-700 manufactured by Sanyo Chemical Industries, Ltd., and polyester polyols such as Phthalkid W2343 manufactured by Hitachi Chemical Co., Ltd., Watersol S-118, CD-520, Beckolite M-6402-50, and M-6201-40IM manufactured by DIC Corporation, Haridip WH-1188 manufactured by Harima Chemicals Co., Ltd., and ES3604 and ES6538 manufactured by Japan U-Pica Corporation. Examples of suitable resins include polyacrylic polyol resins such as Burnock 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 Toresin FS-350 manufactured by Nagase ChemteX Corporation, carboxyl group-containing resins such as AQUALIC manufactured by Nippon Shokubai Co., Ltd. and Finerex SG2000 manufactured by Lead City Co., Ltd., polyamine resins such as LUCKAMIDE 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 a gel permeation chromatograph "HLC-8120" manufactured by Tosoh Corporation, and calculated in terms of polystyrene.

[0273] Methods for quantifying functional groups in resins include, for example, 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 curve methods obtained from the IR spectra of samples with varying functional group introduction ratios.

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

[0275] [Table 20]

[0276] 〔solvent〕 The solvent for preparing the coating liquid for forming the second layer 214 can be selected from, for example, alcohols, aromatics, halogenated hydrocarbons, ketones, ketone alcohols, ethers, esters, etc. More specifically, organic solvents such as methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, 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 alone or in combination of two or more.

[0277] [Confirmation of curability] The curability of the second layer 214 can be confirmed, for example, as follows. A coating film of a coating liquid for forming the second layer 214 containing a melamine compound or guanamine compound, a resin, and an electron transport substance is formed on an aluminum sheet using a Mayer bar, and the coating film is dried by heating at 160°C for 40 minutes to form the second layer 214. The resulting second layer 214 is immersed in a mixed solvent of cyclohexanone / ethyl acetate = 1 / 1 for 2 minutes and dried at 160°C for 5 minutes. The mass of the second layer 214 before and after immersion is confirmed to ensure 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 a plurality of elements are connected, 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 direct current to alternating current. 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 or the like, all-solid-state batteries, and electric double layer capacitors.

[0279] FIG. 5 shows an example of a moving body according to this embodiment. The moving body 30 has a photoelectric conversion element 31 according to one embodiment of the present invention and a body 32 equipped with this photoelectric conversion element. The photoelectric conversion element 31 is disposed in a position on the body 32 where it can receive external light. If the moving body 30 is an automobile, it may be disposed on the roof. The electrical energy obtained by the photoelectric conversion element 31 may power the moving body 30 or may power other electrical equipment. Electrical energy generated from the power of the moving body 30 may be used to power the photoelectric conversion element 31. If the moving body 30 is an automobile, frictional energy generated by braking may be converted into electrical energy and used to control the photoelectric conversion element 31.

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

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

[0282] The building material 40 according to this embodiment may have a heat dissipation member 43 having a higher thermal conductivity than the photoelectric conversion element 41. When used on a roof or the like, sunlight may increase the temperature of the photoelectric conversion element 41, potentially reducing the photoelectric conversion efficiency. The use of the heat dissipation member 43 can reduce the reduction in photoelectric conversion efficiency. Examples of the heat dissipation member 43 include a metal, an alloy, a liquid metal, and a liquid resin.

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

[0284] The building material 40 according to this embodiment has a photoelectric conversion layer containing perovskite, which allows it to be a building material with excellent design, and the reflective layer provides excellent photoelectric conversion efficiency. In other words, it can be a building material with excellent photoelectric conversion efficiency and vivid colors. [Example]

[0285] The present invention will be described in more detail below using examples and comparative examples. The present invention is not limited to the following examples without departing from the gist of the present invention. In the following description of the examples, "parts" are by mass unless otherwise specified.

[0286] First Embodiment (Reference Embodiment) <Particle selection and manufacturing example> (Particles 1 to 8: titanium oxide particles) Titanium oxide (manufactured by Teika) with a volume average particle size of 50 to 600 nm was used.

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

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

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

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

[0291] A titanium niobium sulfate solution containing 33.7 g of titanium (calculated as TiO2) and 2.9 g of niobium (calculated as Nb2O5) was prepared. 100 g of core particles were dispersed in pure water to prepare a 1 L suspension, which was then heated to 60°C. The titanium niobium sulfate solution and 10 mol / L sodium hydroxide were added dropwise over 3 hours so that the pH of the suspension was between 2 and 3. After the entire amount was added dropwise, the pH was adjusted to near neutral, and a flocculant was added to precipitate the solids. The supernatant was removed, filtered, washed, and dried at 110°C to obtain an intermediate containing 0.1 wt% of organic matter derived from the flocculant (calculated as C). This intermediate was then calcined in nitrogen gas at 800°C for 1 hour to produce particles 11.

[0292] [Table 21]

[0293] <Preparation example of coating solution for reflective layer> When the reflective layer did not contain a binder material, the particles were dissolved in 1,500 parts of 1-methoxy-2-propanol as a solvent to obtain a solution. 30 parts of the particles were added to this solution, and the resulting solution was placed in a vertical sand mill using 1,500 parts of glass beads with an average particle size of 1.0 mm as a dispersion medium. The dispersion was subjected to a dispersion treatment for 4 hours at a dispersion temperature of 23±3°C and a rotation speed of 1,500 rpm (circumferential speed of 5.5 m / s), obtaining a dispersion. The glass beads were removed from this dispersion using a mesh to prepare a reflective layer coating.

[0294] When a binder material was added to the reflective layer, a phenolic resin or polyamide resin was dissolved in 1,500 parts of 1-methoxy-2-propanol as a solvent to obtain a solution. The particles were added to this solution at a desired weight ratio relative to the resin. The resulting solution was placed in a vertical sand mill using 1,500 parts of glass beads with an average particle size of 1.0 mm as a dispersion medium. The dispersion was then dispersed for 4 hours at a temperature of 23±3°C and a rotation speed of 1,500 rpm (circumferential speed of 5.5 m / s). The glass beads were removed from the dispersion using a mesh to prepare the reflective layer coating.

[0295] <Preparation example of photoelectric conversion layer paint> (Paint 1: MAPbI3 paint) 4 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 dissolve the lead iodide.

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

[0297] (Paints 3-5: MAPbI (1-x) Br x paint) Paint 1 and Paint 2 were mixed in the weight ratios shown in Table 22 to prepare the paint.

[0298] [Table 22]

[0299] <Example 1-1> Spiro-OMeTAD (180 mg) was dissolved in chlorobenzene (1 mL) as a hole transport material on an ITO glass substrate under a N2 atmosphere. To this chlorobenzene solution, lithium-bis(trifluoromethanesulfonyl)imide (170 mg) was dissolved in acetonitrile (1 mL) to form an acetonitrile solution (37.5 μL), 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, the substrate was baked at 100°C for 10 minutes to form a 300 nm thick hole transport layer.

[0300] Next, a photoelectric conversion layer coating material 4 was applied to the hole transport layer by spin coating, and baked at 100° C. for 10 minutes to form a photoelectric conversion layer having a thickness of 300 nm.

[0301] Next, a coating material in which particles 6 and phenolic resin were dispersed at a weight ratio of 80 / 1 was applied to the photoelectric conversion layer by spin coating, and baked at 130°C for 30 minutes to form a reflective layer with a thickness of 300 nm.

[0302] Then, a 0.09 cm2 thick film with a thickness of 80 nm was applied to the reflective layer. 2 A photoelectric conversion element was fabricated by forming a gold electrode on the substrate by vacuum deposition.

[0303] <Example 1-2> The layers up to the photoelectric conversion layer were laminated in the same manner as in Example 1-1, and a coating material having particles 6 dispersed therein was formed into a film by spin coating, followed by baking at 130°C for 30 minutes to form a reflective layer with a thickness of 300 nm. Thereafter, a gold electrode with a thickness of 80 nm was formed on the reflective layer by vacuum deposition to produce a photoelectric conversion element.

[0304] <Examples 1-3 to 1-19> The charge transport layer was laminated in the same manner as in Example 1-1, and a photoelectric conversion layer paint shown in Table 23 was spin-coated to form a film, which was then baked at 100°C for 10 minutes to form a 300 nm thick active layer. Next, a paint containing dispersed particles shown in Table 23 was spin-coated to form a film, which was then baked at 130°C for 30 minutes to form a 300 nm thick reflective layer. Thereafter, a 80 nm thick, 0.09 cm2 area reflective layer was deposited on the reflective layer. 2 A photoelectric conversion element was fabricated by forming a gold electrode on the substrate by vacuum deposition.

[0305] <Example 1-20> The same preparation as in Example 1-1 was carried out except that the weight ratio of particles 6 to phenolic resin was 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 particles 6 to phenolic resin was 2 / 1.

[0307] <Example 1-22> The preparation was carried out in the same manner as in Example 1-20, except that polyamide was used as the binder resin.

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

[0309] <Comparative Example 1-1> The same preparation as in Example 1-1 was carried out except that particles 6 were replaced with titanium oxide having a volume average particle size of 30 nm.

[0310] <Comparative Example 1-2> The same preparation as in Example 1-2 was carried out except that particles 6 were replaced with titanium oxide having a volume average particle size of 30 nm.

[0311] <Comparative Example 1-3> The same preparation as in Example 1-14 was carried out except that particles 6 were replaced with titanium oxide having a volume average particle size of 30 nm.

[0312] <Evaluation> The photoelectric conversion elements obtained in each of the examples and comparative examples were evaluated as follows.

[0313] (wavelength α at which the reflectance of the reflective layer in the visible light region is maximized) FIG. 7 shows the spectrum of the element of Example 1-1. FIG. 7(a) shows the reflectance spectrum of the reflective layer, and FIG. 7(b) shows the absorption spectrum of the photoelectric conversion layer. As shown in FIG. 7(a), the wavelength α at which the reflectance of the reflective layer in the visible light region (360 nm to 830 nm) is maximized is 656 nm. As shown in FIG. 7(b), the optical absorption coefficient of the photoelectric conversion layer reaches a maximum value of 1.92 (AU) in the visible light region at 360 nm. Meanwhile, the optical absorption coefficient at wavelength α (656 nm) is 0.64 (AU). Therefore, for the element of Example 1-1, the wavelength α was within the wavelength range 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.

[0314] In addition, in the elements of the other examples, the wavelength α was within the wavelength range in which the light 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 element of the comparative example, the wavelength α was outside the range of wavelengths in which the light absorption coefficient of the photoelectric conversion layer was 1 / 5 or more of the maximum value in the visible light region.

[0316] (Power generation efficiency evaluation) A power supply (KEITHLEY, 236 model) was connected between the electrodes of the photoelectric conversion element, and the intensity was 100 mW / cm 2 A solar simulator (manufactured by Yamashita Denso Co., Ltd.) was used to irradiate the device with a constant amount of light from the glass substrate side, and the generated current and voltage were measured to evaluate the photoelectric conversion efficiency.

[0317] [Table 23]

[0318] As described above, the photoelectric conversion element according to the present invention exhibited a photoelectric conversion efficiency superior to that of the comparative example. Furthermore, as measured, the element not only exhibited excellent photoelectric conversion efficiency but also exhibited vivid colors.

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

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

[0321] (Conductive particles 7) Conductive particles 7 were produced in the same manner as in the production process of 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 production were both 250 nm.

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

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

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

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

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

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

[0328] (Conductive particles 14) Titanium oxide particles with an average major axis diameter a and an average minor axis diameter b of 200 nm were used as core particles. 250 g of core particles were dispersed in water to prepare a 2 L aqueous suspension, which was then 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 (parallel addition) over 2 hours to adjust the pH of the suspension to 10. After the addition was completed, the suspension was filtered, washed, and dried at 110°C for 12 hours. The dried product was then heat-treated in a nitrogen gas flow (1 L / min) at 550°C for 1 hour to produce conductive particles 14.

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

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

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

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

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

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

[0335] (Conductive particles 21) Strontium titanate particles with an average major axis diameter a and an average minor axis diameter b of 100 nm were used as core particles. 140 mg of methylhydrogenpolysiloxane was added to 7 g of core particles while the edge runner was running, and the mixture was mixed and stirred for 30 minutes under a linear load of 588 N / cm (60 kg / cm). The stirring speed was 22 rpm. Carbon black particles (volume average particle diameter 20 nm, volume resistivity 1.0 × 10 2 7 g of methylhydrogenpolysiloxane-coated strontium titanate particles (7 g of methylhydrogenpolysiloxane-coated strontium titanate particles) was added with the edge runner running, and the mixture was further mixed and stirred for 60 minutes at a linear load of 588 N / cm (60 kg / cm). After adhering carbon black to the surface of the methylhydrogenpolysiloxane-coated strontium titanate particles in this way, the mixture was dried in a dryer at 80°C for 60 minutes to produce conductive particles 21 shown in Table 24.

[0336] (Conductive particles 22, 23) Strontium titanate particles having an average major axis diameter a and an average minor axis diameter b of 100 nm were used as core particles. A 10 nm thick copper coating was formed on the surface of the strontium titanate particles by electroless plating, yielding conductive particles 22 shown in Table 24. Similarly, a 10 nm thick silver coating was formed by electroless silver plating, yielding conductive particles 23 shown in Table 24.

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

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

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

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

[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, lithium-bis(trifluoromethanesulfonyl)imide (170 mg) was dissolved in acetonitrile (1 mL) to form an acetonitrile solution (37.5 μL), and t-butylpyridine (TBP, 17.5 μL) were added and mixed to prepare a hole transport material solution. The hole transport material solution was spin-coated onto an ITO glass substrate under a N2 atmosphere and baked at 100 °C for 10 minutes to form a 300 nm-thick hole transport layer.

[0343] Next, an active layer coating solution was prepared by dissolving 4 parts lead iodide and 1.4 parts methylammonium iodide in 4.5 parts dimethylformamide as a solvent and stirring for 24 hours at 60° C. This was spin-coated onto the hole transport layer and baked at 100° C. for 10 minutes to form an active layer with a thickness of 300 nm.

[0344] Phenolic resin (phenolic resin monomer / oligomer) as a binder (product name "Plyofen J-325", manufactured by DIC, resin solid content: 60% by mass, density after curing: 1.3 g / cm 2 5 parts of the conductive particles 1 were dissolved in 1,500 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 the resulting solution was placed in a vertical sand mill using 1,500 parts of glass beads with an average particle size of 1.0 mm as a dispersion medium. The dispersion was dispersed for 4 hours at a temperature of 23±3°C and a rotation speed of 1,500 rpm (circumferential speed of 5.5 m / s), obtaining a dispersion. The glass beads were removed from the dispersion using a mesh to prepare a coating solution for the conductive layer.

[0345] The conductive layer coating solution was then applied onto the active layer by spin coating, followed by baking in air at 150° C. for 10 minutes to form a conductive layer with a thickness of 500 nm.

[0346] Then, a 0.09 cm thick film with an area of ​​80 nm was applied to the conductive layer. 2 A photoelectric conversion element was fabricated by forming a gold electrode on the substrate by vacuum deposition.

[0347] A power supply (KEITHLEY, 236 model) was connected between the electrodes of the photoelectric conversion element, and the intensity was 100 mW / cm 2 The photoelectric conversion efficiency was evaluated by irradiating the device with a constant amount of light using a solar simulator (manufactured by Yamashita Denso Co., Ltd.) and measuring the generated current and voltage. The results of the short-circuit current density and photoelectric conversion efficiency are shown in Table 25.

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

[0349] (Example 2-27) A coating liquid for the conductive layer was prepared as follows.

[0350] One part of a butyral resin (product name: BM-1, manufactured by Sekisui Chemical Co., Ltd.) as a polyol resin and one part of a 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. 20 parts of the conductive particles 2 shown in Table 24 were added to this solution, and the mixture was placed in a vertical sand mill using 1100 parts of glass beads with an average particle size of 1.0 mm as a dispersion medium. The mixture was dispersed for 4 hours at a rotation speed of 1500 rpm (circumferential speed of 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 prepared in the same manner as in Example 2-1 except for using the above conductive layer coating liquid, and the photoelectric conversion efficiency was evaluated. The results of the short-circuit current density and photoelectric conversion efficiency are shown in Table 25.

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

[0353] (Example 2-29) A photoelectric conversion element was prepared in the same manner as in Example 2-1, except that no phenolic resin was used in preparing the coating liquid for the conductive layer and that conductive particles 2 shown in Table 24 were used as the conductive particles, and the photoelectric conversion efficiency was evaluated. The results of the 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 produced and its photoelectric conversion efficiency was evaluated in the same manner as in Example 2-1, except that the conductive particles used in preparing the coating solution for the conductive layer were changed to any of conductive particles 27 to 29 shown in Table 24. The results of the short-circuit current density and photoelectric conversion efficiency are shown in Table 25.

[0355] In the elements of Comparative Examples 2-1 and 2-2, the wavelength α at which the reflectance of the reflective layer in the visible light region was maximized was outside the range of wavelengths at which the light absorption coefficient of the photoelectric conversion layer was 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 (product name: BM-1, manufactured by Sekisui Chemical Co., Ltd.) as a resin were dissolved in a mixed solution of 50 parts of methyl ethyl ketone and 50 parts of dimethylacetamide. 0.031 parts of dioctyltin diuralate as a catalyst was added to the resulting solution to prepare a coating solution for an underlayer as the second layer 214. This coating solution was applied by spin coating to an FTO glass substrate as the substrate 216 on which the cathode 215 was formed. After application, the solution was heated at 160°C for 30 minutes to polymerize (cure) the solution, thereby forming a 500 nm-thick underlayer.

[0358] Next, lead iodide was dissolved in N,N-dimethylformamide (DMF) as a metal halide compound to prepare a 1M solution. This was then spin-coated onto the underlayer to form a film. 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 baked in air at 100°C for 10 minutes to form a 500-nm-thick perovskite layer as the first layer 213.

[0359] Next, Spiro-OMeTAD (180 mg) as a hole transport material was dissolved in chlorobenzene (1 mL). To this chlorobenzene solution, lithium-bis(trifluoromethanesulfonyl)imide (170 mg) was dissolved in acetonitrile (1 mL) to form an acetonitrile solution (37.5 μL), 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, the substrate was baked in air at 100°C for 10 minutes to form a 300 nm-thick hole transport layer as the third layer 212.

[0360] Thereafter, a gold electrode serving as an anode 211 having a thickness of 80 nm was formed on the hole transport layer by vacuum deposition, thereby completing a photoelectric conversion element.

[0361] [evaluation] [Structure of the base layer] The structure of the underlayer was analyzed as follows. A photoelectric conversion element for structural analysis of the underlayer was immersed in a chlorobenzene solvent for 5 minutes, and ultrasonic waves were applied to peel off the hole transport layer. Next, the perovskite layer was polished using wrapping tape (C2000: manufactured by Fuji Photo Film Co., Ltd.), and then dried at 100°C for 10 minutes to prepare a photoelectric conversion element for structural analysis of the underlayer. 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 underlayer. A 5 mm square was cut out from the center of the photoelectric conversion element to prepare a sample for structural analysis of the underlayer. The above-mentioned solid 13 The structure represented by formula (U1) (specific examples of Tables 1 to 11) and D were confirmed by C-NMR measurement, mass spectrometry measurement, MS spectrum measurement by pyrolysis GC analysis, and characteristic absorption measurement by infrared spectroscopy. 1 The number of atoms in the main chain of the structure is shown in Table 26.

[0362] [Power generation efficiency evaluation] A power supply (KEITHLEY, 236 model) was connected between the electrodes of the photoelectric conversion element, and the intensity was 100 mW / cm 2The photoelectric conversion efficiency was evaluated by irradiating the device with a constant amount of light using a solar simulator (manufactured by Yamashita Denso Co., Ltd.) and measuring the generated current and voltage. The results of the 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 reference examples) > Photoelectric conversion elements were prepared and evaluated in the same manner as in Example 3-1, except that the electron transporting compound and the isocyanate compound in the coating solution for the undercoat layer used in Example 3-1 were changed as shown in Tables 26 and 27.

[0364] <Comparative Examples 3-1 to 3-3> A photoelectric conversion element was prepared and evaluated in the same manner as in Example 3-1, except that the coating solution for the undercoat layer used in Example 3-1 was changed as shown in Table 28, using only an electron transporting compound and not using an isocyanate compound or resin.

[0365] <Comparative Example 3-4> A photoelectric conversion element was prepared and evaluated in the same manner as in Example 3-1, except that the coating solution for the undercoat layer used in Example 3-1 was changed as shown in Table 28, without using an electron transporting compound, and instead using an isocyanate compound and a resin.

[0366] [Table 26]

[0367] [Table 27]

[0368] [Table 28]

[0369] In Tables 26 to 28, "parts by mass of electron transport compound" refers to the content (parts by mass) of the electron transport compound in the undercoat layer coating liquid. "parts by mass of isocyanate compound" refers to the content (parts by mass) of the isocyanate compound in the undercoat layer coating liquid. "parts by mass of resin" refers to the content (parts by mass) of the resin in the undercoat layer coating liquid.

[0370] In comparing the Examples and Comparative Examples, as in Comparative Examples 3-1 to 3-3, when the underlayer was formed using only an electron transport compound, dissolution of the underlayer was observed when the perovskite layer was applied, and film properties were significantly deteriorated. It is believed that this is why the characteristics as a photoelectric conversion element could not be measured. Furthermore, since Comparative Example 3-4 does not contain an electron transport compound, it is believed that electrons cannot move from the perovskite layer.

[0371] <Example 3-74 (Reference Example)> A coating solution for the underlayer was prepared by dissolving 5 parts of the electron transport compound (E-1-8), 3.5 parts of the 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 dimethylacetamide and 100 parts of methyl ethyl ketone. This coating solution was applied to an FTO glass substrate by spin coating. After application, the solution was heated at 160°C for 30 minutes to polymerize (cure) the solution, forming a 500 nm thick underlayer. Thereafter, 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)> Photoelectric conversion elements were prepared and evaluated in the same manner as in Example 3-74, except that the electron transporting compound, melamine compound, and guanamine compound in the coating solution for the undercoat layer used in Example 3-74 were changed as shown in Tables 29 and 30.

[0373] <Comparative Examples 3-5 to 3-7> A photoelectric conversion element was prepared and evaluated in the same manner as in Example 3-74, except that in the coating solution for the undercoat layer used in Example 3-74, only an electron transporting compound was used, and no melamine compound, guanamine compound, or resin was used, and the changes were made as shown in Table 31.

[0374] <Comparative Example 3-8> A photoelectric conversion element was prepared and evaluated in the same manner as in Example 3-74, except that the coating solution for the undercoat layer used in Example 3-74 was changed as shown in Table 31, without using an electron transporting compound, and instead using a melamine compound, a guanamine compound, and a resin.

[0375] [Table 29]

[0376] [Table 30]

[0377] [Table 31]

[0378] In Tables 29 to 31, "parts by mass of electron transport compound" refers to the content (parts by mass) of the electron transport compound in the undercoat layer coating liquid. "parts by mass of melamine compound" and "parts by mass of guanamine compound" refer to the content (parts by mass) of the melamine compound and guanamine compound in the undercoat layer coating liquid. "parts by mass of resin" refers to the content (parts by mass) of the resin in the undercoat layer coating liquid.

[0379] In comparing the Examples and Comparative Examples, as in Comparative Examples 3-5 to 3-7, when the underlayer was formed using only an electron transport compound, dissolution of the underlayer was observed when the perovskite layer was applied, and film properties were significantly deteriorated. It is believed that this is why the characteristics as a photoelectric conversion element could not be measured. Furthermore, since Comparative Example 3-8 does not contain an electron transport compound, it is believed that electrons cannot move from the perovskite layer. [Explanation of symbols]

[0380] 2: substrate, 3: first electrode, 4: charge transport layer, 5: photoelectric conversion layer, 6: reflective 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 between an anode and a cathode, and a second layer between the cathode and the first layer; The photoelectric conversion element, wherein the second layer has at least one of a structure represented by the following formula (U1) and a structure represented by the following formula (U2): 【Chemistry 1】 (In formulas (U1) to (U2), R 1 and R 3 each independently represents a substituted or unsubstituted alkylene group having 1 to 10 atoms in the main chain, or a substituted or unsubstituted phenylene group. R 2 represents a single bond, a substituted or unsubstituted alkylene group having 1 to 10 atoms in the main chain, or a substituted or unsubstituted phenylene group. 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 of the groups represented by the following formulae (A-1) to (A-6). B 1 represents a group represented by any one of the following formulas (B-1) to (B-3). D 1 is a group having 5 to 15 atoms in the main chain, represented by the following formula (D): E 1 is a group represented by any one 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 each independently represents 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 is O, S, NH, or NR 15 (R 15 is an alkyl group. R 2 represents a single bond, a substituted or unsubstituted alkylene group having 1 to 10 atoms in the main chain, or a substituted or unsubstituted phenylene group. 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 12 represents a hydrogen atom or an alkyl group. Ar 2 represents a substituted or unsubstituted phenylene group, wherein 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. A 1 and A 2 represents any of the groups represented by the formulae (A-1) to (A-5). E 1 is a group represented by any one of the following formulas (E-1) to (E-3). o, p, and q each independently represent 0 or 1, and the sum of o, p, and q is 1 or more and 3 or less. The arrow indicates the R 3 (The symbol indicates the side that binds to the 【Chemistry 4】 (In formula (D), R 4 , R 5 , R 6 and R 7 each independently represents 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 is O, S, NH, or NR 15 (R 15 is an alkyl group. Ar 1 and Ar 2 each independently represents a substituted or unsubstituted phenylene group, wherein 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. A 2 represents a group represented by any one of the formulae (A-1) to (A-6). l, m, n, o, p, and q each independently represent 0 or 1, and the sum of l, m, and n, and the sum of o, p, and q is 1 or more and 3 or less. 【Transformation 5】 (In formulas (E-1) to (E-3), R 101 ~R 106 , R 201 ~R 210 , R 301 ~R 304 R 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. 101 ~R 106 One of them, R 201 ~R 210 One of them, R 301 ~R 304 represents a single bond. Substituents of the substituted alkyl group include an alkyl group, an aryl group, a halogen atom, and a carbonyl group. Substituents of the substituted aryl group or the substituted heterocyclic group include a halogen atom, a nitro group, a cyano group, an alkyl group, a halogen-substituted alkyl group, an alkoxy group, and a carbonyl group.

2. The above D 1 2. The photoelectric conversion element according to claim 1, wherein is a group having 10 to 15 atoms in the main chain.

3. The R 4 , R 5 , R 6 and R 7 and each independently represent 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 4. The photoelectric conversion element according to claim 1, wherein: 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 comprising: the photoelectric conversion element according to claim 1; and a power storage section connected to the photoelectric conversion element.

7. A photoelectric conversion device comprising: the photoelectric conversion element according to claim 1; and an inverter connected to the photoelectric conversion element.

8. A moving body comprising: the photoelectric conversion element according to claim 1; and a body provided with the photoelectric conversion element.

9. A building material comprising: the photoelectric conversion element according to claim 1 ; and a protective member or a heat dissipation member that protects the photoelectric conversion element.

Images