Photoelectric conversion element, photoelectric conversion device, mobile body, and building material

Abstract

Provided is a photoelectric conversion element having improved conversion efficiency. The photoelectric conversion element includes a first electrode, a second electrode, and a photoelectric conversion layer that is disposed between the first electrode and the second electrode and that includes a crystal having a perovskite structure. The photoelectric conversion element includes a charge transport layer containing a phthalocyanine crystal between the photoelectric conversion layer and the first electrode. In an X-ray diffraction spectrum, using a CuKα ray, of the phthalocyanine crystal, a peak exists in a range in which a Bragg angle 2θ is from 28.0° to 29.0°, and a lattice spacing d1 [nm] calculated from a value of 2θ of the peak satisfies 0.3100 ≤ d1 ≤ 0.3160.

Description

Photoelectric conversion element, photoelectric conversion device, mobile body, and building material

[0001] The present invention relates to a photoelectric conversion element, a photoelectric conversion device, a mobile object, and a building material.

[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 is growing in solar cells that directly convert sunlight into electrical energy. Here, a solar cell refers to a cell that generates current and voltage by utilizing the photovoltaic effect, in which light energy from sunlight is absorbed and electrons and holes are generated.

[0003] Currently, n-p diode-type silicon (Si) single crystal-based solar cells with a light energy conversion efficiency of over 20% are widely known and are actually used for solar power generation. However, these require high-temperature processing steps and the materials themselves are expensive, resulting in high costs per unit of power. Furthermore, there are also supply issues due to the limited silicon resources.

[0004] On the other hand, solar cells using organic materials (hereinafter referred to as "organic solar cells") do not require high-temperature processing and can be produced using a sheet-like substrate in a so-called roll-to-roll method, which is expected to reduce costs. However, further improvements in power generation efficiency and durability are desired for the practical application of organic solar cells. In particular, perovskite solar cells, which have crystals with a perovskite structure as a photoelectric conversion layer, have excellent photoelectric conversion properties, and development toward practical use of solar cells is progressing. For example, it has been reported that perovskite solar cells suffer from problems such as destruction of perovskite crystals due to the intrusion of moisture in the air and migration of ions from each layer into other layers, resulting in issues with the durability of solar cells. To address this issue, active research is being conducted on forming a layer around the photoelectric conversion layer to improve durability.

[0005] Patent Document 1 describes a technology for improving the photoelectric conversion efficiency and durability of a solar cell by forming a compound layer containing a compound with a phthalocyanine skeleton in a hole transport layer. Patent Document 2 describes improving the photoelectric conversion efficiency (hereinafter also referred to as "PCE") by forming a layer containing a phthalocyanine compound between a hole transport layer (hereinafter also referred to as "charge transport layer") and a perovskite. Non-Patent Document 1 describes improving the conversion efficiency by incorporating copper phthalocyanine into a hole transport layer.

[0006] JP 2016-149805 A JP 2022-168820 A

[0007] F. Wang, et al, J. Phys. Chem. C 2017, 121, 3, 1562

[0008] However, the above-mentioned conventional techniques require further improvement in conversion efficiency for practical application. Therefore, an object of the present invention is to provide a photoelectric conversion element with improved conversion efficiency. Another object of the present invention is to provide a photoelectric conversion device, a mobile object, and a building material that include the above-mentioned photoelectric conversion element.

[0009] The above object is achieved by the present invention as follows: That is, the present invention provides a photoelectric conversion element having a first electrode, a second electrode, and a photoelectric conversion layer containing a crystal of a perovskite structure, which is disposed between the first electrode and the second electrode, wherein the photoelectric conversion element has a charge transport layer containing a phthalocyanine crystal between the photoelectric conversion layer and the first electrode, and an X-ray diffraction spectrum of the phthalocyanine crystal using CuKα radiation has a peak in a range where the Bragg angle 2θ is 28.0° or more and 29.0° or less, and the lattice spacing d calculated from the value of 2θ of the peak is １ [nm] is 0.3100≦d １ ≦0.3160. The present invention also relates to a photoelectric conversion device having the above-described photoelectric conversion element. The present invention also relates to a mobile object having the above-described photoelectric conversion element. The present invention also relates to a building material having the above-described photoelectric conversion element.

[0010] According to the present invention, a photoelectric conversion element with improved conversion efficiency can be provided.

[0011] Fig. 1 is a schematic cross-sectional view in the thickness direction of one example of one embodiment of the photoelectric conversion element of the present invention. Fig. 2 is a schematic cross-sectional view in the thickness direction of another example of one embodiment of the photoelectric conversion element of the present invention. Fig. 3 is a perspective view schematically showing one embodiment of a moving body including the photoelectric conversion element of the present invention. Fig. 4 is a perspective view schematically showing one embodiment of a building material including the photoelectric conversion element of the present invention.

[0012] One embodiment of the present invention relates to a photoelectric conversion element. The photoelectric conversion element of the present invention is a photoelectric conversion element having a first electrode, a second electrode, and a photoelectric conversion layer containing a crystal of a perovskite structure, disposed between the first electrode and the second electrode, wherein the photoelectric conversion element has a charge transport layer containing a phthalocyanine crystal between the photoelectric conversion layer and the first electrode, and an X-ray diffraction spectrum of the phthalocyanine crystal using CuKα radiation has a peak in a range where the Bragg angle 2θ is 28.0° or more and 29.0° or less, and the lattice spacing d calculated from the value of 2θ of the peak １ [nm] is 0.3100≦d １ ≦0.3160.

[0013] According to Patent Document 2, when a photoelectric conversion layer contains crystals with a perovskite structure, submicron irregularities occur on the surface. It is presumed that filling the recesses of such irregularities with pigment particles made of phthalocyanine crystals stabilizes the interfacial bond with the electrode, resulting in high photoelectric conversion efficiency. However, it has been found that this alone is insufficient to achieve higher photoelectric conversion efficiency.

[0014] The inventors have investigated the phthalocyanine crystal of the present invention, and have found that in an X-ray diffraction spectrum using CuKα radiation, a peak exists in the Bragg angle 2θ range of 28.0° or more and 29.0° or less, and the lattice spacing d calculated from the value of 2θ of the peak is １ [nm] is 0.3100≦d １It has been found that the photoelectric conversion efficiency can be further improved by the ratio of .alpha. to .beta.

[0015] Although the details of why high photoelectric conversion efficiency can be obtained in the present invention are not clear, the inventors speculate as follows. Phthalocyanine molecules are known to have a planar shape, and their π orbitals extend in a direction (hereinafter also referred to as the "vertical direction") perpendicular to the molecular plane (molecular axis direction). Therefore, phthalocyanine crystals have a columnar structure in which planes are stacked face-to-face due to intermolecular interactions of the π bonding properties of the planar molecules. It is believed that the peak in the phthalocyanine crystal where the Bragg angle 2θ is in the range of 28.0° to 29.0° indicates that the phthalocyanine crystals are stacked in the vertical direction between the charge generating layer and the first electrode (the molecular spacing is approximately 3 Å according to the Bragg equation).

[0016] As mentioned above, vertical stacking is the direction in which the π electron clouds overlap, so the lattice spacing d １ The smaller the π electron clouds, the stronger the overlapping, and therefore the efficiency of the transport of carriers moving within the film increases, thereby improving the photoelectric conversion efficiency.

[0017] On the other hand, phthalocyanine crystals have the property of absorbing light to generate electric charges, and are widely known to be used as a material for generating photocarriers in, for example, electrophotographic photosensitive members. When the photoelectric conversion element of the present invention is irradiated with light, the phthalocyanine crystals also absorb a portion of the light to generate electron pairs, and it is expected that these electron pairs will hinder the transport of carriers from the photoelectric conversion layer toward the first electrode. Lattice spacing d １ By increasing the value of , the efficiency of electron pair generation in the phthalocyanine crystal is reduced, and the efficiency of carrier transport is increased, thereby improving the photoelectric conversion efficiency.

[0018] According to the above mechanism, the lattice spacing d １ The present inventors presume that by controlling the valence rate of the carriers to fall within an appropriate range, it becomes possible to increase the efficiency of carrier transport and improve the photoelectric conversion efficiency.

[0019] The present invention will be described in detail below with reference to preferred embodiments. The present invention is not limited to the following embodiments, and any modifications or improvements to the following embodiments based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention are also included in the scope of the present invention.

[0020] In this specification, the term "layer" refers not only to a layer having a clear boundary or a flat thin-film layer, but also to a layer having a concentration gradient in which the contained elements gradually change, or to a layer that can combine with other layers to form a complex and intricate structure.

[0021] FIG. 1 is a cross-sectional view schematically illustrating an example of the configuration of one embodiment of a photoelectric conversion element of the present invention. The photoelectric conversion element 1 in FIG. 1 has a second electrode 3, an electron transport layer 4, a photoelectric conversion layer 5, a charge transport layer 6, a second charge transport layer 7, and a first electrode 8 on a substrate 2. One of the first electrode 8 and the second electrode 3 is an anode and the other is a cathode, and current can be extracted by connecting the first electrode 8 and the second electrode 3 to an external circuit. The photoelectric conversion element 1 preferably has a second charge transport layer 7. When the photoelectric conversion element 1 has the second charge transport layer 7, the charge transport layer containing phthalocyanine crystals (charge transport layer 6) becomes the first charge transport layer.

[0022] The photoelectric conversion layer 5 is excited by light incident through the substrate 2, the second electrode 3, and the electron transport layer 4, or through the first electrode 8, the charge transport layer 6, and the second charge transport layer 7, and generates electrons or holes. That is, the photoelectric conversion layer 5 generates a current between the first electrode 8 and the second electrode 3. The electron transport layer 4 is a layer disposed between the photoelectric conversion layer 5 and the two electrodes 3 and 8, and may not be formed in some cases. A structure in which multiple electron transport layers 4 and photoelectric conversion layers 5 are stacked may be used. This structure may also be called a tandem structure. Alternatively, as shown in FIG. 2 , a structure may be used in which the first electrode 8, the second charge transport layer 7, the charge transport layer 6, the photoelectric conversion layer 5, the electron transport layer 4, and the second electrode 3 are disposed on the substrate 2. Each component will be described below.

[0023] [Photoelectric Conversion Element] The photoelectric conversion element 1 of the present invention includes a first electrode 8, a second electrode 3, and a photoelectric conversion layer 5 containing a crystal of a perovskite structure and disposed between the first electrode 8 and the second electrode 3, and further includes a charge transport layer containing a phthalocyanine crystal between the photoelectric conversion layer 5 and the first electrode 8. In order to improve the photoelectric conversion efficiency, the photoelectric conversion elements may be stacked in a tandem configuration. The photoelectric conversion elements to be stacked are not limited to the type of photoelectric conversion element, and may include a perovskite solar cell using a crystal of a perovskite structure for the photoelectric conversion layer 5, a silicon solar cell, a CIGS solar cell, or the like.

[0024] Methods for forming each layer, including the photoelectric conversion layer and the charge transport layer, of the photoelectric conversion element 1 of the present invention include a coating method and a vapor deposition method. Examples of coating methods include dip coating, spin coating, spray coating, inkjet coating, meniscus coating, screen coating, roll coating, die coating, blade coating, curtain coating, and wire bar coating. The coating method involves preparing a coating solution for each layer, which will be described later, applying the solution in the desired layer order, and drying the solution. A desired method can be selected from these film formation methods depending on the layer. Each layer will be described below.

[0025] [Substrate] The photoelectric conversion element 1 of the present invention may include a substrate 2, for example, a transparent glass substrate such as soda lime glass or alkali-free glass, a ceramic substrate, or a transparent plastic substrate. In Fig. 1, when light is taken in from the first electrode 8 side, an opaque material can be used for the substrate 2, and when light is taken in from the second electrode 3 side, the substrate 2 is made of a transparent material.

[0026] [Electrodes] There are no particular limitations on the materials for the first electrode 8 and the second electrode 3, and conventionally known materials can be used. For example, metals such as gold, silver, titanium, and copper, sodium, sodium-potassium alloy, lithium, magnesium, carbon, carbon nanotubes, aluminum, magnesium-silver mixture, magnesium-indium mixture, aluminum-lithium alloy, and Al / Al ２ O ３Examples of transparent electrode materials include CuI, ITO (indium tin oxide), and SnO ２ Examples of the conductive transparent material include AZO (aluminum zinc oxide), IZO (indium zinc oxide), GZO (gallium zinc oxide), FTO (fluorine-doped tin oxide), and ATO (antimony-doped tin oxide), as well as conductive transparent polymers. These materials may be used alone or in combination of two or more.

[0027] Of the first electrode 8 and the second electrode 3, at least one electrode on the light incident side is a transparent electrode, and the other may be a transparent electrode or may double as a reflective layer formed of a light-reflective material, or may be a transparent electrode with a reflective layer on the side opposite to the light incident side. For the photoelectric conversion element 1, it is preferable that the first electrode 8 is a positive electrode. When the first electrode 8 is on the light incident side, the second electrode 3 may be a transparent electrode and the substrate 2 may be a reflective layer. The transparent electrode may be a patterned electrode.

[0028] [Photoelectric Conversion Layer] The photoelectric conversion layer 5 has a crystal with a perovskite structure. The crystal with a perovskite structure used in the present invention is preferably represented by the following general formula [1]: ABX ３ [1] In the general formula [1], A is a monovalent cation of an organic molecule or a metal atom, B is a divalent metal cation, and X is a monovalent halide anion. For example, A in the general formula [1] is an organic molecule such as C ｐ N ｑ H ｒ (p, q, and r are all positive integers) Specific examples include methylammonium and formamidium.

[0029] The metal atom is not particularly limited, but lithium, cesium, sodium, potassium, and rubidium are preferred. These organic molecules or metal atoms may be used alone or in combination of two or more.

[0030] When the constituent cation A is too large to fit within a crystal with a three-dimensional perovskite structure, the resulting crystal is a two-dimensional perovskite structure, a 2.5-dimensional perovskite structure crystal having both two-dimensional and three-dimensional properties, a two-layer crystal of a three-dimensional and two-dimensional perovskite structure, or a crystal with a mixed three-dimensional and two-dimensional perovskite structure, all of which function as the photoelectric conversion layer 5. A two-layer crystal of a three-dimensional and two-dimensional perovskite structure refers to a crystal in which crystals of a three-dimensional and two-dimensional perovskite structure are stacked as independent, separate layers, and a mixed three-dimensional and two-dimensional perovskite refers to a crystal with a structure in which regions or domains of both a two-dimensional or 2.5-dimensional layered and three-dimensional perovskite structure crystal are mixed.

[0031] The crystal of the two-dimensional perovskite or 2.5-dimensional perovskite structure is preferably represented by the following general formulas [2] to [4]: ２ A ｎ－１ B ｎ X ３ｎ＋１ [2] R''A ｎ－１ B ｎ X ３ｎ＋１ [3] R''' ２ A ｎ B ｎ X ３ｎ＋１ [4] In the above general formulas, general formula [2] forms an RP (Ruddlesden-Popper) type perovskite structure, general formula [3] forms a DJ (Dion-Jacobson) type perovskite structure, and general formula [4] forms an ACI (Alternating cations in the interlayer) type perovskite structure.

[0032] R', R'', and R''' in the above general formulas [2] to [4] are organic molecules or metal cations which may have a substituent, and specific examples thereof include ethylammonium, propylammonium, n-butylammonium, n-hexylammonium, n-octylammonium, 1,6-hexadiammonium, isobutylammonium, 3-(nonafluoro-tert-butyloxy)propylamine, 1,3-propanediammonium, 1,5-pentamethylenediamine, octyldiammonium, 2,2-(ethylenedioxy)bis(ethylammonium), 5-aminovaleric acid, 4-tert-butylammonium, N,N'-dimethylethylene-1,2-diammonium, 2,2,3,3,3-pentafluoropropylammonium, guanidium, propylammonium, propargylamine, alkylammonium, cyclohexylmethylammonium, 4-(aminomethyl)piperidinium, piperidinium, pyrrolidinium, cyclohexylmethylammonium, 4-(aminomethyl)piperidinium, piperidinium, pyrrolidinium, cyclohexylmethylammonium, 4-(aminomethyl)piperidinium, 4-(aminomethyl)pyridin ... ammonium, 4-fluorophenethylammonium, 4-fluorophenethylammonium, trifluoromethylbenzylammonium, pentafluorobenzylammonium, pentafluorophenylethylammonium, 4-methoxyphenethylammonium, imidazolium, pyridinium, 3-thiophenemethylammonium, 2-thiopheneethylammonium, 2-thiopheneformamidium, 2-thiophenemethylammonium, 1-naphthylmethylammonium, 2-naphthylmethylammonium, phenethylammonium, phenylammonium, benzylammonium, 2,5-thiophenedimethylammonium, phenylpropylammonium, 1,4-phenylenedimethanamine, 3-phenyl-2-propene-1-ammonium, phenylbutylammonium, 4-tert-butylbenzylammonium, 3-(aminomethyl)piperidinium, and 4-(aminomethyl)piperidinium are preferred.

[0033] In the general formulas [1] to [4], B represents a metal atom, such as lead, tin, bismuth, zinc, titanium, antimony, nickel, iron, cobalt, silver, copper, gallium, germanium, magnesium, calcium, indium, aluminum, manganese, chromium, molybdenum, and europium. Among these, lead, tin, and bismuth are preferred from the viewpoint of electron orbital overlap. These metal atoms may be used alone or in combination of two or more.

[0034] X in the general formulas [1] to [4] above is a halogen atom or the like, and examples thereof include chlorine, bromine, iodine, sulfur, and selenium. These halogen atoms may be used alone or in combination of two or more. Among these, halogen atoms are preferred because the inclusion of a halogen in the structure makes the perovskite structure crystal more soluble in organic solvents, enabling application to inexpensive printing methods and the like. Furthermore, iodine is more preferred because it narrows the energy band gap of the perovskite structure crystal.

[0035] Specifically, 3D perovskite, 2D perovskite, and mixed 3D / 2D perovskite are MAPbI ３ and FAPbCl ３、 FAPbI ３ , MAPbI ｘ Br ３－ｘ , MAPbI ｘ Cl ３－ｘ , Cs ０．０５ (MA ０．１７ FA ０．８３ ) ０．９５ Pb(I ０．８３ Br ０．１７ ) 3, {Cs ｘ１ (FA ｘ２ MA １－ｘ２ ) １－ｘ１} ｘ３ Pb(I ｘ４ Br １－ｘ４ ) ｘ５ , Cs ０．０５ FA ０．８８ MA ０．０７ PbI ２．５６ Br ０．４４ , (FAPbI ３ ) ０．９５ (MAPbBr３ ) ０．０５ 、(FAPbI ３ ) ０．８５ (MAPbBr ３ ) ０．１５ 、CsPbI 3、 CsPbBr3、Cs ｘ (MA) １－ｘ PbI ３ 、Cs ｘ (FA) １－ｘ PbI ３ 、MA ｘ (FA) １－ｘ PbI ３ 、MA ０．１７ FA ０．８３ Pb(I ０．８３ Br ０．１７ )3、Cs ０．１５ FA ０．８５ PbI ２．５５ Br ０．４５ 、Cs ０．０５ FA ０．８８ MA ０．０７ PbI ２．５６ Br ０．４４ 、Cs ０．１５ FA ０．８５ PbI ２．５５ Br ０．４５ 、(PEA) ２ (MA) ２ Pb ３ I １０ 、(PTA) ２ (MA) ４ Pb ５ I １６ 、(PEA) ２ (MA) ４ Pb ５ I １６ 、(ThMA) ２ (MA) ２ Pb ３ I １０ 、(3BBA) ２ (MA) ２ Pb ３ I １０ 、(ThMA)2(FA)4Pb5I 16 、(4FPEA) ２ (FA ０．３ MA ０．７ ) ４ Pb ５ I １６ 、(PDMA)FA２ Pb ３ I １０ 、(3AAMPY)(MA) ３ Pb ４ I １３ 、(PDMA)MA ５ Pb ６ I １９ 、(PDMA)MA ３ Pb ４ I １３ 、(TTDMA)MA ３ Pb ４ I １３ 、(TTDMA)MA ４ Pb ５ I １６ 、 (BA ０．９ PEA ０．１ ) ２ MA ４ Pb ５ I １６ 、 (BA ０．９ PEA ０．１ ) ２ MA ３ Pb ４ I １３ 、(4FFEA) ２ MA ３ Pb ４ I １３ 、(4FFEA) ２ MA ４ Pb ５ I １６ 、(BA) ２ MA ２ Pb ３ I １０ 、(BA) ２ MA ３ Pb ４ I １３ 、(TEA) ２ MA ２ Pb ３ I １０ 、(BA) ２ MA ４ Pb ５ I １６ 、(BA) ２ MA ３ Pb ４ I １３ 、Cs.Br ３ 、CsSﾎI ３ 、FA ０．７５ MA ０．２５ Se０．９５ Ge ０．０５ I ３ , FAMASnGeI ３ , FASnBr ３ , FASnI ３ , M.A. ２ Sn ３ I ８ , MASnBr ３ , MASnGeI ３ , MASnI ３ is preferred. Depending on the purpose, the A site, B site, or X site in the above general formula may be adjusted to be insufficient or excessive, and the combination of x1 to x5 may be changed depending on the purpose. Combinations of x1 to x5 are, for example, as shown in Table 1. Particularly preferred ranges are 0.03≦x1≦0.10, 0.80≦x2≦0.96, 0.95≦x3≦1.05, 0.80≦x4≦0.96, and 2.95≦x5≦3.05. MACl may also be included as a material for forming perovskite crystals.

[0036]

[0037] In the above specific examples, "MA" represents methylammonium, "FA" represents formamidinium, "PEA" represents phenethylammonium, "PTA" represents phenyltriethylammonium, "ThMA" represents 2-thiophenemethylammonium, "3BBA" represents 3-bromobenzylammonium, "3AMPY" represents 3-(aminomethyl)pyridine, "PDMA" represents 1,4-phenylenedimethaneammonium, "TTDMA" represents thieno[3,2-b]thiophene-2.5-diyldimethaneammonium, "4FPEA" represents 4-fluorophenethylammonium, "BA" represents butylammonium, and "TEA" represents 2-thiophenethylammonium.

[0038] The perovskite crystal preferably has a cubic structure in which a metal atom B is located at the body center, an organic molecule A at each vertex, and a halogen atom X at the face center. Although the details are not clear, it is presumed that such a structure allows the orientation of the octahedra in the crystal lattice to be easily changed, thereby increasing the mobility of electrons in the perovskite crystal and improving the photoelectric conversion efficiency of the photoelectric conversion element 1.

[0039] The perovskite crystal used in the present invention is preferably a crystalline semiconductor. A crystalline semiconductor refers to a semiconductor in which a scattering peak can be detected by measuring an X-ray scattering intensity distribution. When the perovskite crystal is a crystalline semiconductor, the mobility of electrons in the perovskite crystal increases, improving the photoelectric conversion efficiency of the photoelectric conversion element 1.

[0040] The thickness of the photoelectric conversion layer 5 according to the present invention is preferably 5 nm or more and 2000 nm or less. A thickness of 5 nm or more allows sufficient absorption of light, and a thickness of 2000 nm or less allows generated charges to be transported to each electrode. A more preferred lower limit is 50 nm or more, a more preferred upper limit is 1200 nm, an even more preferred lower limit is 100 nm, and an even more preferred upper limit is 1000 nm.

[0041] [Charge Transport Layer] The charge transport layer 6 of the present invention has phthalocyanine crystals. In the phthalocyanine material of the present invention, "crystals" means that in X-ray diffraction measurement described below, the half-value width of a peak present in the Bragg angle 2θ range of 28.0° to 29.0° is 1.0° or less.

[0042] In the photoelectric conversion element 1 of the present invention, the phthalocyanine crystal is preferably a gallium phthalocyanine crystal, and more preferably a hydroxygallium phthalocyanine crystal. The phthalocyanine crystal used in the present invention may have a central element, such as Ga, Cu, Ti, Zn, Si, V, Pb, Pt, Co, Sn, Mg, Fe, Al, or Mn. Of these, gallium phthalocyanine compounds having Ga as the central element are preferred. Among gallium phthalocyanines, hydroxygallium phthalocyanine is more preferred. The phthalocyanine crystal may be a derivative having a phthalocyanine skeleton. Gallium phthalocyanine has good electronic interaction with resins having Lewis base functional groups, and it is believed that hydroxygallium phthalocyanine in particular has a stronger interaction with Lewis bases due to the presence of hydroxy groups, thereby improving photoelectric conversion efficiency.

[0043] Specific examples of the phthalocyanine crystal of the present invention are listed below: Examples of the phthalocyanine crystal of the present invention include hydroxygallium phthalocyanine, chlorogallium phthalocyanine, copper phthalocyanine, zinc phthalocyanine, phthalocyanine, cobalt phthalocyanine, titanyl phthalocyanine, dichlorotin phthalocyanine, magnesium phthalocyanine, tin phthalocyanine, lead phthalocyanine, iron phthalocyanine, vanadyl phthalocyanine, chloroaluminum phthalocyanine, nickel phthalocyanine, dichlorosilicon phthalocyanine, indium chlorophthalocyanine, manganese phthalocyanine, chloroiron phthalocyanine, and platinum phthalocyanine.

[0044] The phthalocyanine crystal of the present invention is, for example, naphthalocyanine, magnesium naphthalocyanine, copper naphthalocyanine, magnesium naphthalocyanine, cobalt naphthalocyanine, vanadyl naphthalocyanine, tin naphthalocyanine, or dichlorotin naphthalocyanine. In the present invention, the chemical structure of the phthalocyanine crystal or the like can be confirmed, for example, by nuclear magnetic resonance (NMR) spectroscopy.

[0045] In the photoelectric conversion element 1 of the present invention, the charge transport layer 6 preferably contains a resin. From the viewpoint of film-forming properties and charge transport ability, the content of the resin in the charge transport layer 6 is preferably 3 parts by mass or more and 30 parts by mass or less, and more preferably 5 parts by mass or more and 20 parts by mass or less, when the content of the phthalocyanine crystals in the charge transport layer 6 is taken as 100 parts by mass. When the resin is contained, the film-forming properties are improved, and therefore the number of leak points caused by the roughness of the photoelectric conversion layer 5 is reduced, thereby improving the photoelectric conversion efficiency. The resin content can be quantified using a nuclear magnetic resonance (NMR) device or a gas chromatography device.

[0046] The molecular weight of the resin is preferably 10,000 or more. Resins preferably used in the present invention include polyester resins, polycarbonate resins, polyvinyl acetal resins, polyvinyl butyral resins, acrylic resins, polyvinyl alcohol resins, cellulose resins, polystyrene resins, polyvinyl acetate resins, and polyvinyl chloride resins.

[0047] Furthermore, the resin preferably has a glass transition temperature of 95° C. or lower. Within this range, the resin is likely to come into close contact with the charge transport material (charge transport particles), allowing for more effective charge distribution. The glass transition temperature can be determined by differential scanning calorimetry (DSC).

[0048] The charge transport layer may contain an aromatic ring compound containing a hydroxyl group, and from the viewpoint of film-forming properties and charge transport ability, the content of the aromatic ring compound containing a hydroxyl group in the charge transport layer is preferably 1% by mass or more and 30% by mass or less, and more preferably 5% by mass or more and 20% by mass or less, relative to the content of the cyclic conjugated compound formed by covalently bonding multiple pyrrole rings. Examples of aromatic ring compounds containing a hydroxyl group that are preferably used in the present invention include calixarene compounds.

[0049] In the photoelectric conversion element 1 of the present invention, in an X-ray diffraction spectrum using CuKα rays for the charge transport layer 6 having phthalocyanine crystals, a peak exists in the range of Bragg angle 2θ of 28.0° or more and 29.0° or less, and the lattice spacing d １ [nm] is 0.3100≦d １ The photoelectric conversion element 1 of the present invention has a lattice spacing d calculated from the value of 2θ of the peak. １ [nm] is 0.3120≦d １ It is preferable that 0.3145≦d １ It is more preferable that the relationship be ≦0.3155.

[0050] In the present invention, the lattice spacing d calculated from the value of 2θ of a peak present in the range of Bragg angle 2θ of 28.0° or more and 29.0° or less in an X-ray diffraction spectrum using CuKα radiation １ [nm] is the angle θ obtained from the peak in the range of 28.0° to 29.0°. １[rad], and X-ray wavelength λ [nm] (λ = 0.15418 in the case of an X-ray diffraction spectrum using CuKα rays), and the Bragg equation (1) below can be used to calculate: １ = λ / (2 sin θ １ ) ... (1)

[0051] Here, when a peak derived from phthalocyanine crystal exists between 28.0° and 29.0°, the angle θ at the point with the highest peak intensity is defined as θ １ Here, the terms "particle", "crystallite" and "crystallite size d" of the phthalocyanine crystal in the present invention are used. ２ In the present invention, a "particle" of a phthalocyanine crystal is a primary particle of the phthalocyanine crystal, which is formed by the aggregation of phthalocyanine molecules. On the other hand, a "crystallite" of a phthalocyanine crystal is the smallest unit part of the particle of the crystal that can be regarded as a single crystal of phthalocyanine, and the crystallite size d ２ means the size of the crystallite.

[0052] In the present invention, the crystallite size d of the phthalocyanine crystal ２ The crystallite size d2 was calculated from the peaks in the Bragg angle 2θ range of 28.0° to 29.0° in the X-ray diffraction spectrum using CuKα radiation. The crystallite size d2 was calculated from the Scherrer formula using the Scherrer constant K [−], the X-ray wavelength λ [nm], the half-width β [rad], and θ １ Using [rad], it can be expressed by the following formula (2): ２ =K・λ / (β・cosθ １ ) ... (2)

[0053] Crystallite size d ２ The larger the crystallite size d calculated from the half width of the peak, the fewer the number of crystallite interfaces that cause the obstruction of the transport of carriers injected from the photoelectric conversion layer 5, and therefore the increase in resistance and the voltage drop due to the accumulation of carriers are suppressed, and the photoelectric conversion efficiency is improved. ２ But, d ２ ≧19.5, ２It is more preferable that the relationship be ≧ 20.0.

[0054] On the other hand, if the crystallites are too large, the crystal size varies, which deteriorates the surface properties of the charge transport layer 6, thereby reducing the shunt resistance and adversely affecting the photoelectric conversion efficiency. ２ But, d ２ It is preferable that the number average particle size of the phthalocyanine crystals is 50 nm or more and 150 nm or less.

[0055] Dispersion methods for particle-forming phthalocyanine crystals include methods using a paint shaker, a sand mill, a ball mill, and a liquid collision type high-speed disperser. Since the load on the phthalocyanine material varies depending on the dispersion method, １ , d ２ The values ​​vary widely.

[0056] Among these, sand mills use the shearing force of the rotating disk inside the mill and the grinding media, such as glass beads, to granulate the crystals. However, depending on the dispersion conditions, such as the dispersion time, amount of beads, and disk rotation speed, the crystallinity changes, resulting in a change in the lattice spacing d １ and crystallite size d ２ For example, if the dispersion time is extended to a degree that does not cause over-dispersion (aggregation of particles, formation of fragments, etc.), d １ and d ２ In addition, by changing the temperature during dispersion, １ While keeping the change of d small, ２ It is possible to change d by balancing the change in temperature that promotes the growth of crystallites and the change in dispersion strength that occurs due to temperature change. １ , d ２ It is also assumed that the amount of change in d changes depending on the type of central element of the phthalocyanine crystal, the crystal form, or the solvent used for dispersion. １ and d ２ will vary greatly.

[0057] The phthalocyanine crystals may contain a portion of the solvent used for dispersion. The solvent contained in the crystals is preferably any one selected from the group consisting of N-methylformamide, N-ethylformamide, N-propylformamide, and dimethyl sulfoxide, with N-methylformamide being even more preferred. That is, in the photoelectric conversion element 1 of the present invention, the phthalocyanine crystals preferably contain N-methylformamide. These materials have large pKa and dipole moments, which increases the charge imbalance within the material, increasing carrier mobility and improving photoelectric conversion efficiency. The method for introducing the organic compound into the crystals is not particularly limited, but examples include allowing the organic compound to coexist during the crystallization process. The amount of the organic compound in the crystals can be controlled by changing various conditions during the crystallization process, such as the treatment time and treatment intensity.

[0058] If the photoelectric conversion layer 5 has high roughness, it is thought that the photoelectric conversion layer 5 and the first electrode 8 come into direct contact, resulting in a decrease in photoelectric conversion efficiency due to a decrease in shunt resistance and a decrease in durability during long-term storage. Therefore, by increasing the film thickness of the charge transport layer 6 to a certain level or more, it is possible to suppress contact between the photoelectric conversion layer 5 and the first electrode 8 and improve photoelectric conversion efficiency and durability. On the other hand, if the film thickness of the charge transport layer 6 is too thick, the efficiency of carrier transport decreases, so it is preferable not to make the film thickness of the charge transport layer 6 too thick. In the photoelectric conversion element 1 of the present invention, the average film thickness of the charge transport layer 6 is preferably 30 nm to 400 nm, more preferably 50 nm to 180 nm.

[0059] The measurement of the X-ray diffraction spectrum of the charge transport layer 6 and the confirmation of the contained phthalocyanine crystals can be carried out, for example, by removing the layers above the charge transport layer 6 of the photoelectric conversion element 1 with an organic solvent such as chloroform, and then exposing the surface of the charge transport layer 6. In the examples of the present invention, unless otherwise specified, the measurement of the X-ray diffraction spectrum and the confirmation of the contained phthalocyanine crystals were carried out in a state where the charge transport layer 6 was exposed by the above-mentioned method.

[0060] [X-ray Diffraction Measurement] In the present invention, the X-ray diffraction spectrum of the exposed charge transport layer 6 was measured under the following conditions. The obtained X-ray diffraction spectrum of the charge transport layer 6 was subjected to smoothing treatment, and the peak positions in the range of 28.0° to 29.0° were determined as θ １ [rad], and the half-width of the peak was taken as the half-width β [rad]. In the analysis, the Scherrer constant K varies depending on the shape of the crystal and how the half-width is taken, but in the present invention, calculations were performed assuming K = 0.89. Measuring equipment used: X-ray diffraction equipment RINT-TTRII, manufactured by Rigaku Electric Co., Ltd. X-ray tube: Cu X-ray wavelength: Kα1 Tube voltage: 50 KV Tube current: 300 mA Scan method: 2θ-θ scan Scan speed: 0.5° / min Sampling interval: 0.01° Start angle 2θ: 5.0° Stop angle 2θ: 35.0° Goniometer: Rotor horizontal goniometer (TTR-2) Filter: None Detector: Scintillation counter Incident monochromator: Used Slit: Variable slit (parallel beam method) Counter monochromator: Not used Divergence slit: Open Divergence vertical limiting slit: 10.00 mm Scattering slit: Open Receiving slit: Open

[0061] [Analysis of Compound Amount] In the examples of the present invention, the surface of the charge transport layer 6 of the photoelectric conversion element 1 was wiped with a cotton swab or the like soaked in a solvent, and then dissolved in heavy water sulfuric acid, followed by 1H-NMR measurement (apparatus: AVANCE3-500, manufactured by BRUKER). The peeled-off components were also subjected to mass and structural analyses such as GPC, MALDI-TOF-MS, IR, and gas chromatography, as well as elemental analyses such as EDX and XPS, and these, together with the results of the X-ray diffraction measurement, confirmed the type of phthalocyanine crystals, and the presence of organic compounds contained in the crystals such as N-methylformamide, and compounds such as resins.

[0062] [Measurement of Average Film Thickness] In the present invention, the average film thickness of the charge transport layer 6 was confirmed by cutting the photoelectric conversion element 1, fixing it to an inclined sample stage, and then observing the cross section using a scanning electron microscope (hereinafter also referred to as "SEM") (apparatus: Carl Zeiss, Smart SEM). In the observation, the charge transport layer 6 was distinguished from other layers based on the difference in contrast of the observed image and composition analysis using an SEM-EDX function, and the average film thickness of the charge transport layer 6 portion was measured by image processing of images taken at a magnification of 50,000 times. Five randomly selected locations were photographed, and the average of the five average values ​​was taken as the average film thickness of the charge transport layer 6.

[0063] [Second Charge Transport Layer] From the viewpoint of compatibility of the charge transport layer film, the photoelectric conversion element 1 of the present invention preferably has a second charge transport layer 7 between the charge transport layer 6 and the first electrode 8. In this case, the charge transport layer containing phthalocyanine crystals (charge transport layer 6) serves as the first charge transport layer. The material of the second charge transport layer 7 is not particularly limited, and examples thereof include spirofluorene compounds, triphenylamine compounds, chrysene compounds, pyrene compounds, phthalocyanine compounds, carbazole compounds, fluorene compounds, phenylcyclohexane compounds, benzidine compounds, phenoxazine compounds, phenylenediamine compounds, thiocyanate compounds, and thiophene compounds. In particular, from the viewpoint of compatibility at the film interface, it is preferable for the material to have an aromatic ring, and Spiro-OMeTA and PTAA are more preferable.

[0064] The second charge transport layer may contain a dopant as an additive to improve its charge transport capability. Examples of a substance that can be used as a dopant include lithium compounds such as bis(trifluoromethanesulfonyl)imide lithium, cobalt compounds such as [tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine)cobalt(3)tris(bis(trifluoromethylsulfonyl)imide)], boron compounds such as tetrakis(pentafluorophenyl)borate, molybdenum compounds such as tris[1-(methoxycarbonyl)-2-(trifluoromethyl)-ethane-1,2-dithiolene]molybdenum, organic compounds having a tetracyanoquinodimethane skeleton such as 2,3,4,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane, and organic compounds having a pyridine skeleton such as 4-tert-butylpyridine.

[0065] [Electron Transport Layer] In the photoelectric conversion element 1 of the present invention, an electron transport layer 4 may be disposed between the second electrode 3 and the photoelectric conversion layer 5, as shown in Fig. 1. The material of the electron transport layer 4 is not particularly limited, and examples thereof include N-type conductive polymers, N-type low-molecular-weight organic semiconductors, N-type metal oxides, N-type metal sulfides, alkali metal halides, alkali metals, and surfactants. Specific examples thereof include cyano group-containing polyphenylene vinylene, boron-containing polymers, bathocuproine, bathophenanthrene, hydroxyquinolinatoaluminum, oxadiazole compounds, benzimidazole compounds, naphthalene tetracarboxylic acid compounds, fullerene compounds, perylene derivatives, phosphine oxide compounds, phosphine sulfide compounds, fluoro group-containing phthalocyanines, titanium oxide, zinc oxide, indium oxide, tin oxide, gallium oxide, tin sulfide, indium sulfide, and zinc sulfide.

[0066] The thickness of the electron transport layer 4 is preferably 1 nm or more at the lower limit and 2000 nm or more at the upper limit. If the thickness of the electron transport layer 4 is 1 nm or more, holes can be sufficiently blocked, and if the thickness is 2000 nm or less, resistance during electron transport is unlikely to occur, resulting in high photoelectric conversion efficiency. The thickness is more preferably 3 nm or less at the lower limit and 1000 nm or less at the upper limit, and even more preferably 5 nm or less at the lower limit and 500 nm or less at the upper limit.

[0067] <Application Examples> Application examples of the present invention relate to photoelectric conversion devices, mobile objects, and building materials. [Photoelectric Conversion Device] The photoelectric conversion device of the present invention includes the photoelectric conversion element described above. A photoelectric conversion device can be constructed by using multiple photoelectric conversion elements of the present invention. When multiple photoelectric conversion elements are connected, such a photoelectric conversion device can also be called a photoelectric conversion cell or a photoelectric conversion module. The photoelectric conversion element may be stacked with elements having different absorption wavelengths to increase the output voltage. The photoelectric conversion device may also include the photoelectric conversion element 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, all-solid-state batteries, and electric double-layer capacitors. To impart functionality such as maintaining or increasing the amount of incident light, a surface layer that is resistant to water and dirt, or a function to collect or guide light, may be added.

[0068] [Mobile object] The mobile object of the present invention has the photoelectric conversion element described above. FIG. 3 is a perspective view schematically showing one embodiment of a mobile object equipped with the photoelectric conversion element of the present invention. The mobile object 30 has a photoelectric conversion element 31 of the present invention and a body 32 equipped with the photoelectric conversion element 31. The photoelectric conversion element 31 is disposed in a position on the body 32 where it can receive external light. If the mobile object 30 is an automobile, it may be disposed on the roof. The electrical energy obtained by the photoelectric conversion element 31 may power the mobile object 30 or may power other electrical equipment. Electrical energy generated from the power of the mobile object 30 may be used to power the photoelectric conversion element 31. If the mobile object 30 is an automobile, frictional energy generated by braking may be converted into electrical energy and used to control the photoelectric conversion element 31.

[0069] The mobile object 30 may be, for example, an automobile, a motorcycle, a railroad vehicle, a ship, an artificial satellite, an airplane, or a flying object including 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.

[0070] [Building Material] The building material of the present invention has the photoelectric conversion element described above. Fig. 4 is a perspective view schematically showing one embodiment of a building material including the photoelectric conversion element of the present invention. The building material 40 may be the roof of a building. The building material 40 of this embodiment has the photoelectric conversion element 41 of the present invention, a protective member 42 that protects the photoelectric conversion element 41, a heat dissipation member 43, and exterior coverings 44a and 44b.

[0071] The building material 40 of the present invention 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.

[0072] Furthermore, the building material 40 of the present invention may have exterior coatings 44a and 44b. The exterior coatings 44a and 44b may emit different colors or may be the same. The exterior coatings 44a and 44b may be made of the same material or different materials. Paint or a transparent substrate may be used as the exterior coating. Materials with low light absorption and high heat insulation properties are preferred.

[0073] In addition to the above application examples, the following application examples can be mentioned: Portable devices include, for example, calculators, sensors, and small solar panels; Wearable devices include, for example, eyeglass-type terminals, wristwatch-type terminals, and portable medical equipment; Sheet structures supported by multiple frames include, for example, tents, greenhouses, and truck beds; Fixed structures include, for example, road panels, floating panels, building materials that take advantage of the flexibility of the substrate, wall-type building materials, glass-type building materials, and mega solar panels.

[0074] [Method for manufacturing photoelectric conversion element] The method for manufacturing the photoelectric conversion element of the present invention includes the steps of forming a first electrode, forming a second electrode, forming a photoelectric conversion layer containing crystals with a perovskite structure between the first electrode and the second electrode, and forming a charge transport layer between the photoelectric conversion layer and the first electrode. Each step of the manufacturing method will be described below.

[0075] (Step of forming a first electrode and step of forming a second electrode) The method for manufacturing the photoelectric conversion element of the present invention includes a step of forming a first electrode and a step of forming a second electrode. For the step of forming the first electrode and the step of forming the second electrode, an appropriate method can be selected depending on the material of the first electrode and the material of the second electrode, respectively. Examples of such methods include, but are not limited to, sputtering vacuum deposition, CVD (chemical vapor deposition), and SPD (spray pyrolysis deposition). The materials for the first electrode and the second electrode are as described above. When either or both of the first electrode and the second electrode are transparent electrodes, the thickness of the transparent electrode is preferably 0.03 μm or more and 3 μm or less. When manufacturing a solar cell, cutting may be performed between each step to form a circuit. Examples of cutting include mechanical patterning and laser patterning.

[0076] (Modularization Process) The elements having electrodes formed thereon may be sealed. Examples of sealing methods include sealing with a resin or sealing with a film. Examples of materials used for sealing include silazane, silicone rubber, resins having a siloxane skeleton, and glass. In addition, from the viewpoint of suppressing adhesion between elements that occurs when winding in a roll-to-roll manner, the surfaces of the sealed elements may be subjected to a hairline treatment.

[0077] (Step of forming photoelectric conversion layer) A method for manufacturing the photoelectric conversion element of the present invention includes a step of forming a photoelectric conversion layer containing crystals with a perovskite structure between a first electrode and a second electrode. The step of forming the photoelectric conversion layer may include a step of applying a liquid containing the material for the photoelectric conversion layer described above. Examples of application methods include spin coating, blade coating, slit die coating, screen printing, bar coating, casting, print transfer, immersion and lifting, inkjet printing, spraying, and vacuum deposition. Among these, an appropriate method is selected depending on the properties of the photoelectric conversion layer to be produced, such as thickness control and orientation control.

[0078] In order to remove the solvent or dispersion medium from the liquid containing the material of the applied photoelectric conversion layer, annealing may be performed under reduced pressure or in an inert atmosphere (nitrogen or argon atmosphere). The temperature of the annealing is preferably 40° C. or higher and 300° C. or lower, more preferably 50° C. or higher and 150° C. or lower. Note that annealing is preferable because it may increase the contact area at the interface between the stacked layers due to the penetration of the materials constituting each layer into each other, thereby increasing the short-circuit current.

[0079] (Step of Forming Charge Transport Layer) The step of forming the charge transport layer is preferably a method of applying a liquid containing the material for the charge transport layer described above. Examples of the application method include spin coating, blade coating, slit die coating, screen printing, bar coating, casting, print transfer, immersion and lifting, ink jet printing, spraying, and vacuum deposition.

[0080] Examples of the process for forming the charge transport layer include the following: a method in which charge transport particles are disposed on the surface of the photoelectric conversion layer, and then a resin solution in which a resin is dissolved is applied and dried; a method in which a resin solution in which a resin is dissolved is applied on the surface of the photoelectric conversion layer, and then charge transport particles are disposed, and then the resin solution is dried; and a method in which a solution in which charge transport particles are dispersed in a resin solution in which a resin is dissolved is applied on the surface of the photoelectric conversion layer and then dried.

[0081] 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.

[0082] (Steps for Producing Phthalocyanine Crystal 1) Step (1) Under a nitrogen flow atmosphere, 5.46 parts of orthophthalonitrile and 45 parts of α-chloronaphthalene were charged into a reaction vessel, and the vessel was heated to a temperature of 30°C and maintained at this temperature. Next, 3.75 parts of gallium trichloride was charged at this temperature (30°C). The water concentration of the mixed solution at the time of charging was 150 ppm. The temperature was then raised to 200°C. Next, under a nitrogen flow atmosphere, the mixture was reacted at 200°C for 4.5 hours, cooled, and when the temperature reached 150°C, the product was filtered. The resulting filtrate was dispersed and washed using N,N-dimethylformamide at 140°C for 2 hours, and then filtered. The resulting filtrate was washed with methanol and dried, yielding chlorogallium phthalocyanine particles in a yield of 71% by mass.

[0083] Step (2) 4.65 parts of the chlorogallium phthalocyanine particles were dissolved in 139.5 parts of concentrated sulfuric acid at a temperature of 10°C, and the solution was dropped into 620 parts of ice water under stirring to reprecipitate, followed by vacuum filtration using a filter press. No. 5C (manufactured by Advantec Co., Ltd.) was used as the filter. The obtained wet cake (filtrate) was dispersed and washed with 2% aqueous ammonia for 30 minutes, and then filtered using a filter press. Next, the obtained wet cake (filtrate) was dispersed and washed with ion-exchanged water, and then filtered three times using a filter press. Finally, freeze-drying was performed to obtain hydroxygallium phthalocyanine particles (hydrated hydroxygallium phthalocyanine particles) with a solids content of 23% by mass in a yield of 71%. The hydroxygallium phthalocyanine particles were dried in a Hyper Dry dryer (product name: HD-06R, frequency (oscillation frequency): 2455 MHz±15 MHz, manufactured by Nippon Biocon) to obtain hydroxygallium phthalocyanine particles (crystals) with a water content of 1.0 mass % or less.

[0084] Step (3) Five parts of the hydroxygallium phthalocyanine particles were dispersed in a sand mill (TSG-1 / 4G-4U, manufactured by Igarashi Machinery Mfg. Co., Ltd. (now Imex Co., Ltd.), disk diameter: 70 mm, number of disks: 5) containing 100 parts of N-methylformamide solvent and 100 parts of glass beads, with the disks rotated at 300 rpm at 25° C. for 30 hours, followed by filtration and drying to obtain phthalocyanine crystals 1.

[0085] (Preparation Process of Phthalocyanine Crystals 2 to 16) Phthalocyanine crystals 2 to 16 were prepared in the same manner as in the preparation of phthalocyanine crystal 1, except that the solvent used in step (3), the temperature during the dispersion treatment, and the dispersion time were changed as shown in Table 2. Phthalocyanine crystal 14 was prepared by carrying out dispersion, filtration, drying in step (3), and then centrifuging to remove coarse particles.

[0086]

[0087] (Preparation of Resin Solution 1) Resin solution 1 was obtained by dissolving 1.0 g of polyvinyl butyral (trade name: BM-2, manufactured by Sekisui Chemical Co., Ltd., glass transition temperature 71° C.) in 19 g of 2-propanol with stirring for 24 hours.

[0088] (Preparation of Resin Solution 2) Resin solution 2 was obtained by dissolving 1.0 g of polyacrylic acid (molecular weight 5000, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) in 19 g of ethanol with stirring for 24 hours.

[0089] (Preparation of Resin Solution 3) 1.0 g of polymethyl methacrylate (PMMA, manufactured by Sigma-Aldrich, glass transition temperature 70° C.) was dissolved in 19 g of 2-propanol with stirring for 24 hours to obtain Resin Solution 3.

[0090] (Preparation of Resin Solution 4) Resin solution 4 was obtained by dissolving 1.0 g of polymethyl methacrylate (PMMA, manufactured by Sigma-Aldrich, glass transition temperature 100° C.) in 19 g of 2-propanol with stirring for 24 hours.

[0091] Example 1 Formation of Electron Transport Layer A glass substrate with ITO was cleaned, and tin (II) oxide adjusted to a concentration of 3% by mass was applied thereon by spin coating. The substrate was then heated at 150°C for 30 minutes to form a thin-film electron transport layer having a thickness of 15 nm.

[0092] [Formation of Photoelectric Conversion Layer] 22.4 mg of methylammonium bromide, 172 mg of formamidium iodide, and 576 mg of lead iodide were dissolved in 500 μL of N,N-dimethylformamide and 200 μL of dimethyl sulfoxide, and the mixture was stirred for 1 hour (Solution 1). Furthermore, 389.72 mg of cesium iodide was dissolved in 1000 μL of dimethyl sulfoxide, and the mixture was stirred for 1 hour (Solution 2). Then, 40 μL of the dissolved cesium iodide solution (Solution 2) was added to Solution 1 to prepare a photoelectric conversion layer coating solution. This coating solution was spin-coated on the electron transport layer, resulting in the formation of a Cs ０．０５ (FA ０．８３ MA ０．１７ ) ０．９６ Pb(I ０．９５ Br ０．０５ ) ３ A photoelectric conversion layer having a thickness of 500 nm was formed.

[0093] [Formation of Charge Transport Layer] 0.1 g of the phthalocyanine crystal 1 and 0.01 g of a calixarene compound (JP 2003-207913 A) were encapsulated in 10.6 g of 2-propanol and 11 g of zirconia beads, and the mixture was dispersed in a paint shaker (manufactured by Toyo Seiki Co., Ltd.) for 6 hours. Then, 0.2 g of resin solution 1 was added, and the mixture was again dispersed in the paint shaker for 6 hours to prepare a coating liquid for a charge transport layer. The obtained coating liquid for a charge transport layer was spin-coated on the photoelectric conversion layer to form a charge transport layer with a thickness of 100 nm.

[0094] [Formation of Second Charge Transport Layer] 0.15 g of Spiro-OMeTAD, a material for the second charge transport layer, was dissolved in 2.2 g of chlorobenzene. 36 μL of an acetonitrile solution obtained by dissolving 0.2 g of lithium-bis(trifluoromethanesulfonyl)imide in 0.3 g of acetonitrile was added to this chlorobenzene solution, and 36 μL of t-butylpyridine (TBP) were added and mixed. 58 μL of an acetonitrile solution obtained by dissolving 0.11 g of [tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine)cobalt(III) tris(bis(trifluoromethylsulfonyl)imide)] in 0.5 g of acetonitrile was added to the chlorobenzene solution to prepare Charge Transport Coating Liquid 1. Charge Transport Coating Liquid 1 was applied to the charge transport layer by spin coating to form a second charge transport layer with a thickness of 100 nm.

[0095] [Formation of First Electrode] A first electrode having a thickness of 80 nm and an area of ​​0.09 cm2 was formed on the second charge transport layer. ２ A gold electrode was formed by vacuum deposition to obtain a photoelectric conversion element. The resulting photoelectric conversion element was subjected to measurements of the amounts of the above compounds, N-methylformamide, and average film thickness, as well as X-ray diffraction measurements, to determine the composition of the phthalocyanine crystal, the presence or absence of NMF (N-methylformamide) in the phthalocyanine crystal, the film thickness of the charge transport layer, and d1 and d2. The results are shown in Tables 3 and 4.

[0096] (Preparation of Examples 2 and 3) Examples 2 and 3 were prepared in the same manner as in Example 1, except that the type of phthalocyanine crystal used and the amount of phthalocyanine crystal enclosed were changed as shown in Table 3.

[0097] (Preparation of Examples 4 to 28) Examples 4 to 28 were prepared in the same manner as in Example 1, except that the type of phthalocyanine crystals used, the amount of encapsulated phthalocyanine crystals, and the type of resin solution used were changed as shown in Table 3. However, in Examples 14 to 16, the charge transport layer coating liquid was prepared without adding a resin solution and subsequently dispersing with a paint shaker during the formation of the charge transport layer. Furthermore, Example 26 was prepared without forming a second charge transport layer.

[0098]

[0099] (Preparation of Comparative Example 1) Comparative Example 1 was prepared in the same manner as in Example 1, except that the charge transport layer was changed to the particle layer prepared in Example 1 described in JP-A-2022-168820.

[0100] (Preparation of Comparative Example 2) Comparative Example 1 was prepared in the same manner as in Example 1, except that the charge transport layer was changed to the particle layer prepared in Example 9 described in JP-A-2022-168820.

[0101] (Preparation of Comparative Example 3) Comparative Example 3 was prepared in the same manner as in the preparation of Example 18, except that chlorogallium phthalocyanine 1 in the preparation of Example 18 was changed to chlorogallium phthalocyanine 2, which has strong peaks at 9.0±0.2°, 17.6±0.2°, 27.4±0.2°, and 28.8±0.2° in the X-ray diffraction spectrum.

[0102] (Preparation of Comparative Example 4) Comparative Example 4 was prepared in the same manner as in Example 20, except that copper phthalocyanine 1 in the preparation of Example 20 was changed to copper phthalocyanine 2 having strong peaks at 7.0±0.2°, 9.2±0.2°, 12.5±0.2°, 16.8±0.2°, 18.6±0.2°, 21.3±0.2°, 23.8±0.2°, 26.2±0.2°, 28.0±0.2°, and 30.5±0.2° in an X-ray diffraction spectrum.

[0103] (Preparation of Comparative Examples 5 and 6) Comparative Examples 5 and 6 were prepared in the same manner as in Example 1, except that the phthalocyanine crystal 1 in Example 1 was changed as shown in Table 3.

[0104] [Evaluation] [Evaluation of photoelectric conversion efficiency] A power supply (manufactured by Keithley, Model 236) was connected between the electrodes of the photoelectric conversion element, and an intensity of 100 mW / cm ２ The photoelectric conversion efficiency was evaluated by irradiating the sample with a constant amount of light using a solar simulator (manufactured by Yamashita Denso Co., Ltd.) and measuring the generated current and voltage. The series resistance was calculated by approximating the reciprocal of the slope of the obtained current-voltage curve near Voc (open circuit voltage), and the shunt resistance was calculated by approximating the reciprocal of the slope of the obtained current-voltage curve near Jsc (short circuit current density). The results are shown in Table 4.

[0105] [X-ray Diffraction Measurement] X-ray diffraction measurement was performed by the method described above on the sample obtained in Example 1. For the measurement, a sample from which the layers above the charge transport layer were peeled off and a sample from which only the charge transport layer was peeled off were prepared, and the difference between the two data was taken to obtain the X-ray diffraction spectrum of only the charge transport layer, and the values ​​of 2θ and half width were calculated.

[0106] Next, in the production of Example 1, a sample in which the photoelectric conversion layer and a sample in which the charge transport layer were formed were prepared and subjected to X-ray diffraction measurement. The 2θ and full width at half maximum values ​​were the same as the X-ray diffraction results of the sample obtained by peeling off the upper layer. The samples produced in Examples 2 to 28 and Comparative Examples 1 to 6 were evaluated using a sample in which the photoelectric conversion layer and a sample in which the charge transport layer were formed. The results are shown in Table 4.

[0107] [Analysis of Compound Amount and Measurement of Average Film Thickness] The types of compounds in the phthalocyanine crystals, the presence or absence of NMF in the phthalocyanine crystals, the average film thickness of the charge transport layer, and the presence of resin in the charge transport layer were confirmed by the above-mentioned methods. The results are shown in Table 3.

[0108]

[0109] The present invention is not limited to the above-described embodiments, and various modifications and variations can be made without departing from the spirit and scope of the present invention. Therefore, the following claims are appended to apprise the public of the scope of the present invention.

[0110] This application is a Japanese patent application No. 2023-184761 filed on October 27, 2023, Japanese patent application No. 2023-184756 filed on October 27, 2023, Japanese patent application No. 2023-184750 filed on October 27, 2023, Japanese patent application No. 2023-216294 filed on December 21, 2023, Japanese patent application No. 2023-216296 filed on December 21, 2023, Priority is claimed based on Japanese Patent Application No. 2023-216299, Japanese Patent Application No. 2024-022244 filed on February 16, 2024, Japanese Patent Application No. 2024-022251 filed on February 16, 2024, Japanese Patent Application No. 2024-022246 filed on February 16, 2024, and Japanese Patent Application No. 2024-086010 filed on May 28, 2024, the entire contents of which are incorporated herein by reference.

[0111] REFERENCE SIGNS LIST 1 Photoelectric conversion element 2 Substrate 3 Second electrode 4 Electron transport layer 5 Photoelectric conversion layer 6 Charge transport layer 7 Second charge transport layer 8 First electrode 30 Mobile body 31, 41 Photoelectric conversion element 32 Airframe 40 Building material 42 Protective member 43 Heat dissipation member 44a, 44b Exterior

Claims

1. A photoelectric conversion element having a first electrode, a second electrode, and a photoelectric conversion layer containing a crystal of a perovskite structure disposed between the first electrode and the second electrode, wherein the photoelectric conversion element has a charge transport layer containing a phthalocyanine crystal between the photoelectric conversion layer and the first electrode, and in an X-ray diffraction spectrum using CuKα radiation for the phthalocyanine crystal, a peak exists within a range where the Bragg angle 2θ is 28.0° or more and 29.0° or less, and the lattice spacing d calculated from the value of 2θ of the peak １ [nm] is 0.3100≦d １ ≦0.3160.

2. The crystallite size d calculated from the half-width of the peak ２ [nm] is d ２ The photoelectric conversion element according to claim 1 , which satisfies ≧ 19.

5.

3. The crystallite size d calculated from the half-width of the peak ２ [nm] is d ２ The photoelectric conversion element according to claim 1 , which satisfies the following:

4. The crystallite size d calculated from the half-width of the peak ２ [nm] is d ２ The photoelectric conversion element according to any one of claims 1 to 3, which satisfies the following: ≦21.

1.

5. The lattice spacing d １ [nm] is 0.3145≦d １ 5. The photoelectric conversion element according to claim 1, which satisfies ≦0.3155.

6. The photoelectric conversion element according to any one of claims 1 to 5, wherein the charge transport layer contains a resin.

7. The photoelectric conversion element according to any one of claims 1 to 6, further comprising a second charge transport layer between the first electrode and the charge transport layer.

8. The photoelectric conversion element according to any one of claims 1 to 7, wherein the phthalocyanine crystal is a gallium phthalocyanine crystal.

9. The photoelectric conversion element according to any one of claims 1 to 8, wherein the phthalocyanine crystal is a hydroxygallium phthalocyanine crystal.

10. The photoelectric conversion element according to any one of claims 1 to 9, wherein the phthalocyanine crystal contains N-methylformamide.

11. The photoelectric conversion element according to any one of claims 1 to 10, wherein the average film thickness of the charge transport layer is from 50 nm to 180 nm.

12. A photoelectric conversion device comprising the photoelectric conversion element according to any one of claims 1 to 11.

13. A moving object having a photoelectric conversion element according to any one of claims 1 to 11.

14. A building material comprising the photoelectric conversion element according to any one of claims 1 to 11.

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