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

Abstract

To provide a photoelectric conversion element improved in durability and photoelectric conversion efficiency.SOLUTION: A photoelectric conversion element has a first electrode, a second electrode, and a photoelectric conversion layer arranged between the first electrode and the second electrode and including a crystal of a perovskite structure. The photoelectric conversion element has a charge transport layer between the photoelectric conversion layer and the first electrode. The charge transport layer includes a P-type semiconductor crystal and resin. The P-type semiconductor crystal has at least one functional group selected from the group consisting of a hydroxy group, a carboxy group, an amino group, an imino group, and a sulfo group.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a photoelectric conversion element, a photoelectric conversion device, a moving body, and a building material. [Background technology]

[0002] In order to solve the problem 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 hydroelectric power. Among them, interest in solar cells that directly convert sunlight into electrical energy is increasing. Here, a solar cell refers to a cell that generates a current and voltage by utilizing the photovoltaic effect in which light energy from sunlight is absorbed and electrons and holes are generated.

[0003] Currently, np 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 photovoltaic power generation. However, these require high-temperature processing and the materials themselves are expensive, so they have the problem of high cost per unit of power. In addition, there are problems with supply in terms of 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 by the so-called roll-to-roll method, which is expected to reduce costs. However, further improvements in power generation efficiency and durability are required for the practical use of organic solar cells. In particular, perovskite-type solar cells, which have crystals with a perovskite structure as a photoelectric conversion layer, have excellent photoelectric conversion characteristics, so development is being promoted for the practical use of solar cells.

[0005] For example, Patent Document 1 describes a technique for improving peeling from the electrode by including an organic semiconductor and a polymer compound having a glass transition temperature of 100° C. or higher in the hole transport layer. Non-Patent Document 1 describes improving conversion efficiency by mixing copper phthalocyanine and a conductive polymer in the hole transport layer. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2018-170382 A [Non-patent literature]

[0007] [Non-Patent Document 1] Q. Hu,et al,Sol.RRL,2019,3,1800264 Summary of the Invention [Problem to be solved by the invention]

[0008] According to the studies of the present inventors, it has been found that the photoelectric conversion elements described in Patent Document 1 and Non-Patent Document 1 have room for improvement in terms of durability and photoelectric conversion efficiency. SUMMARY OF THE PRESENT EMBODIMENTS Accordingly, an object of the present invention is to provide a photoelectric conversion element having improved durability and photoelectric conversion efficiency, and also to provide a photoelectric conversion device. [Means for solving the problem]

[0009] The present invention relates to A photoelectric conversion element having a first electrode, a second electrode, and a photoelectric conversion layer including a crystal having a perovskite structure and disposed between the first electrode and the second electrode, the photoelectric conversion element has a charge transport layer between the photoelectric conversion layer and the first electrode, the charge transport layer includes a P-type semiconductor crystal and a resin, The photoelectric conversion element is characterized in that the P-type semiconductor crystal has at least one functional group selected from the group consisting of a hydroxy group, a carboxy group, an amino group, an imino group, and a sulfo group. The present invention also provides a method for producing a semiconductor device comprising the steps of: A photoelectric conversion element having a first electrode, a second electrode, and a photoelectric conversion layer including a crystal having a perovskite structure and disposed between the first electrode and the second electrode, the photoelectric conversion element has a charge transport layer between the photoelectric conversion layer and the first electrode, the charge transport layer includes a P-type semiconductor crystal and a resin, The photoelectric conversion element is characterized in that the P-type semiconductor crystal has a functional group capable of acting as a hydrogen bond donor. The present invention also provides a method for producing a method for manufacturing a semiconductor device comprising the steps of: A photoelectric conversion element having a first electrode, a second electrode, and a photoelectric conversion layer including a crystal having a perovskite structure and disposed between the first electrode and the second electrode, the photoelectric conversion element has a charge transport layer between the photoelectric conversion layer and the first electrode, the charge transport layer includes a P-type semiconductor crystal and a resin, The photoelectric conversion element is characterized in that the P-type semiconductor crystal has a Lewis basic functional group. The present invention also relates to a photoelectric conversion device having the above-mentioned photoelectric conversion element. The present invention also relates to a moving object having the above-mentioned photoelectric conversion element. The present invention also relates to a building material having the above-mentioned photoelectric conversion element. Effect of the Invention

[0010] According to the present invention, it is possible to provide a photoelectric conversion element having improved durability and photoelectric conversion efficiency. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of a layer structure in a thickness direction of an embodiment of a photoelectric conversion element of the present invention. [Diagram 2]1 is a perspective view showing a schematic diagram of an embodiment of a moving body including a photoelectric conversion element of the present invention; [Diagram 3] FIG. 1 is a perspective view illustrating a schematic diagram of one embodiment of a building material including a photoelectric conversion element of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] <One embodiment> One embodiment relates to a photoelectric conversion element. The photoelectric conversion element of the present invention comprises: A photoelectric conversion element having a first electrode, a second electrode, and a photoelectric conversion layer including a crystal having a perovskite structure and disposed between the first electrode and the second electrode, A charge transport layer is provided between the photoelectric conversion layer and the first electrode, the charge transport layer includes a P-type semiconductor crystal and a resin, The P-type semiconductor crystal is characterized in that it has at least one functional group selected from the group consisting of a hydroxy group, a carboxy group, an amino group, an imino group, and a sulfo group. The photoelectric conversion element of the present invention further comprises: A photoelectric conversion element having a first electrode, a second electrode, and a photoelectric conversion layer including a crystal having a perovskite structure and disposed between the first electrode and the second electrode, A charge transport layer is provided between the photoelectric conversion layer and the first electrode, the charge transport layer includes a P-type semiconductor crystal and a resin, The P-type semiconductor crystal is characterized in that it has a functional group capable of acting as a hydrogen bond donor. The photoelectric conversion element of the present invention further comprises: A photoelectric conversion element having a first electrode, a second electrode, and a photoelectric conversion layer including a crystal having a perovskite structure and disposed between the first electrode and the second electrode, A charge transport layer is provided between the photoelectric conversion layer and the first electrode, the charge transport layer includes a P-type semiconductor crystal and a resin, The P-type semiconductor crystal is characterized in that it has a Lewis basic functional group.

[0013] As a result of investigations, the present inventors have found that the inclusion of the charge transport layer results in a photoelectric conversion element having excellent durability and conversion efficiency. The reasons for this are believed to be as follows.

[0014] On the perovskite surface, undercoordinated Pb 2+ ions, Pb clusters, iodine vacancies, organic A cation vacancies, undercoordinated I - The surface defects include several types of defects, such as ions. These surface defects can cause recombination of electrons and holes through non-radiative channels, which can lead to deterioration of the photoelectric conversion element and a decrease in the conversion efficiency. In addition, in perovskite solar cells, water molecules from the outside and ions and molecules that make up the photoelectric conversion element can migrate to other layers, destroying the structure of the photoelectric conversion element.

[0015] In response to this, it is believed that the deterioration of durability and conversion efficiency can be prevented by incorporating a P-type semiconductor crystal having a Lewis basic functional group or a functional group that can act as a hydrogen bond donor in the charge transport layer in contact with the photoelectric conversion layer. This is because the Lewis acidic defects present on the perovskite surface are passivated by interaction with the Lewis base, and the hydrogen atoms contained in the functional group are used to fill the I - The reason for this is that the perovskite structure traps ions. Furthermore, since the crystal defects of the perovskite structure are several tens to several hundreds of nanometers in size, it has been found that even when a hole transport layer or an insulating layer is introduced to a thickness of several tens of nanometers between the charge transport layer and the photoelectric conversion layer of the present invention, this contributes to improving durability and conversion efficiency.

[0016] In addition, by including P-type semiconductor crystals and resin in the charge transport layer, it is thought that the functional groups of the resin interact with defects on the perovskite surface that cannot be repaired by P-type semiconductor crystals alone. Furthermore, P-type semiconductor crystals, which have high charge transport properties and hole mobility, do not impede charge transport even in thick films, but by including resin therein, the photoelectric conversion layer can be reliably covered, and durability can be increased while maintaining charge transport.

[0017] As explained above, the respective components exert a synergistic effect on each other, thereby making it possible to achieve the effects of the present invention.

[0018] 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 a person skilled in the art without departing from the spirit of the present invention are also included in the scope of the present invention.

[0019] 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 change gradually, or to a layer that can form a complex structure together with other layers. Elemental analysis of a layer can be performed, for example, by performing TOF-SIMS / FE-TEM / EDS line analysis measurement of a cross section of a photoelectric conversion element to confirm the element distribution of a specific element. Analysis of each layer may be performed by peeling off the completed element to expose the layer to be analyzed. The volume ratio can also be quantified by using the area ratio of the exposed surface or cross section as the volume ratio of the layer.

[0020] 1 is a cross-sectional view showing a schematic configuration of one embodiment of the photoelectric conversion element of the present invention. A second electrode 3, an electron transport layer 4, a photoelectric conversion layer 5, a charge transport layer 6, and a first electrode 7 are provided on a substrate 2. One of the first electrode 7 and the second electrode 3 is an anode and the other is a cathode, and a current can be extracted by connecting the first electrode 7 and the second electrode 3 to an external circuit.

[0021] 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 the first electrode 7 and the charge transport layer 6, and generates electrons or holes. That is, the photoelectric conversion layer 5 generates a current between the first electrode 7 and the second electrode 3. The electron transport layer 4 is a layer disposed between the photoelectric conversion layer 5 and two electrodes (the second electrode 3 and the first electrode 7), and may not be formed in some cases. A form in which a plurality of electron transport layers 4 and photoelectric conversion layers 5 are laminated may be used. Such a form may also be called a tandem structure. Each member will be described below. In addition, a photoelectric conversion element may be fabricated on the substrate 2 in the order of the first electrode 7, the charge transport layer 6, the photoelectric conversion layer 5, the electron transport layer 4, and the second electrode 3.

[0022] [Photoelectric conversion element] The photoelectric conversion element of the present invention is characterized by 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. In addition, in order to improve the photoelectric conversion efficiency, the photoelectric conversion elements may be stacked in a tandem type. 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 perovskite crystal in the photoelectric conversion layer, a silicon solar cell, a CIGS solar cell, and the like.

[0023] Examples of the method for forming each layer of the photoelectric conversion element of the present invention include a coating method and a vapor deposition method. Examples of the coating method 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 is a method in which a coating solution for each layer described below is prepared, coated in the desired layer order, and dried. A desired method can be selected from these film formation methods according to each layer. Each layer will be described below.

[0024] 〔substrate〕 The photoelectric conversion element 1 of the present invention may include a substrate 2, examples of which include a transparent glass substrate such as soda-lime glass or alkali-free glass, a ceramic substrate, a transparent plastic substrate, etc. When light is taken in from the first electrode 7 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.

[0025] 〔electrode〕 There are no particular limitations on the materials for the first electrode 7 and the second electrode 3, and any conventionally known materials can be used. Examples include metals such as gold, silver, titanium, and copper, sodium, sodium-potassium alloy, lithium, magnesium, carbon, aluminum, a magnesium-silver mixture, a magnesium-indium mixture, an aluminum-lithium alloy, an Al / Al2O3 mixture, and an Al / LiF mixture.

[0026] Examples of transparent electrode materials include conductive transparent materials such as CuI, ITO (indium tin oxide), SnO2, AZO (aluminum zinc oxide), IZO (indium zinc oxide), GZO (gallium zinc oxide), FTO (fluorine-doped tin oxide), and ATO (antimony-doped tin oxide), as well as conductive transparent polymers.

[0027] These materials may be used alone or in combination of two or more. At least one of the first electrode 7 and the second electrode 3 on the light incident side is a transparent electrode, and the other may be a transparent electrode or a layer that also serves as a reflective layer formed of a light-reflective material, or may be a transparent electrode provided with a reflective layer on the side opposite to the light incident side. When the first electrode 7 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 electrodes may be patterned electrodes.

[0028] [Photoelectric Conversion Layer] The photoelectric conversion layer 5 has a crystal having a perovskite structure. The crystal having a perovskite structure used in the present invention is preferably represented by the following general formula [1]. ABX3[1] In the above 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.

[0029] In the general formula [1], A is preferably represented by, for example, CpNqHr (where p, q, and r are all positive integers) in the case of an organic molecule. Specific examples include methylammonium and formamidium.

[0030] 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.

[0031] When the constituent A cations are too large to fit within the 3D perovskite crystal, they form 2D perovskite crystals, 2.5D perovskite crystals that have both 2D and 3D properties, bilayer crystals of 3D and 2D perovskite structures, or mixed 3D and 2D perovskite crystals, all of which can function as a photovoltaic layer.

[0032] A bilayer crystal of 3D and 2D perovskite is a crystal in which 3D and 2D perovskite structure crystals are stacked as independent, separate layers, while a mixed 3D / 2D perovskite is a crystal with a structure that combines regions or domains of both 2D or 2.5D layered and 3D perovskite structure crystals.

[0033] The crystals having a two-dimensional perovskite or 2.5-dimensional perovskite structure are preferably represented by the following general formulas [2] to [4] (n is a positive integer). R'2A n-1 B n X 3n+1 [2] R''A n-1 B n X 3n+1 [3] R'''A n B n X 3n+1[4] In the above general formulas, [2] forms an RP (Ruddlesden-Popper) type perovskite structure, [3] forms a DJ (Dion-Jacobson) type perovskite structure, and [4] forms an ACI (Alternating cations in the interlayer) type perovskite structure.

[0034] 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, iso-butylammonium, 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, guanidinium, propylammonium, propargylamine, alkylammonium, cyclohexylmethylammonium, 4-(aminomethyl)piperidinium, piperidinium, pyrrolidinium, cyclohexylmethylammonium, 4-(aminomethyl)piperidinium, piperidinium, pyrrolidinium, cyclohexylmethylammonium, 4-aminomethyl-1,2-di ... xylammonium, 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-butyl-benzylammonium, 3-(aminomethyl)piperidinium, 4-(aminomethyl)piperidinium are preferred.

[0035] In the above general formulas [1] to [4], B is 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.

[0036] X in the above general formulas [1] to [4] is a halogen atom, such as chlorine, bromine, and iodine. These halogen atoms may be used alone or in combination of two or more. Among them, halogen atoms are preferred because the perovskite crystals are easily soluble in organic solvents by containing halogen in the structure, making it possible to apply the perovskite crystals to inexpensive printing methods and the like. Furthermore, iodine is more preferred because the energy band gap of the perovskite crystals is narrowed.

[0037] Specifically, 3D perovskites, 2D perovskites, and mixed 3D / 2D perovskites are MAPbI3, FAPbCl3, FAPbI3, MAPbI x Br 3-x , MAPbI x Cl 3-x , Cs 0.1 (MA 0.17 FA 0.83 ) 0.9 Pb(I 0.9 Br 0.1 ) 3、 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 0.07PbI 2.56 Br 0.44 、(FAPbI3) 0.95 (MAPbBr3) 0.05 、(FAPbI3) 0.85 (MAPbBr3) 0.15 、CsPbI3、CsPbBr3、Cs x (MA) 1-x PbI3,Csx(FA) 1-x PbI3、MA x (FA) 1-x PbI3、MA 0.17 FA 0.83 Pb(I 0.83 Br 0.17 )3、Cs 0.15 FA 0.85 PbI 2.55 Br 0.45 、Cs 0.05 FA 0.88 MA 0.07 PbI 2.56 Br 0.44 、Cs 0.15 FA 0.85 PbI 2.55 Br 0.45 、(AND)2(MA)2Pb3I 10 、(PTA)2(MA)4Pb5I 16 、(AND)2(MA)4Pb5I 16 、(ThMA)2(MA)2Pb3I 10 、(3BBA)2(MA)2Pb3I 10 、(ThMA)2(FA)4Pb5I 16 、(4FPEA)2(FA 0.3 MA 0.7 )4Pb5I 16 、(PDMA)FA2Pb3I 10 、(3AMPY)(MA)3Pb4I 13 、(PDMA)MA5Pb6I 19 、(PDMA)MA3Pb4I 13 、(TTDMA)MA3Pb4I 13 、(TTDMA)MA4Pb5I 16 ,(THAT 0.9 AND 0.1 )2MA4Pb5I 16 ,(THAT 0.9 AND 0.1 )2MA3Pb4I13 , (4FPEA)2MA3Pb4I 13 , (4FPEA)2MA4Pb5I 16 , (BA)2MA2Pb3I 10 , (BA)2MA3Pb4I 13 , (TEA)2MA2Pb3I 10 , (BA)2MA4Pb5I 16 , (BA)2MA3Pb4I 13 is preferred.

[0038] Depending on the purpose, the A site, B site, or X site in the above general formula may be adjusted to be under- or over-adjusted, and the combination of x1 to x5 may be changed depending on the purpose. 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 be included as a material for forming perovskite crystals.

[0039] [Table 1]

[0040] In the above specific examples, "MA" stands for methylammonium, "FA" stands for formamidinium, "PEA" stands for phenethylammonium, "PTA" stands for phenyltriethylammonium, "ThMA" stands for 2-thiophenemethylammonium, "3BBA" stands for 3-bromobenzylammonium, "3AMPY" stands for 3-(aminomethyl)pyridine, "PDMA" stands for 1,4-phenylenedimethaneammonium, "TTDMA" stands for thieno[3,2-b]thiophene-2.5-diyldimethaneammonium, "4FPEA" stands for 4-fluorophenethylammonium, "BA" stands for butylammonium, and "TEA" stands for 2-thiophenethylammonium.

[0041] The crystal with the perovskite structure 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 the presence of such a structure makes it easy to change the orientation of the octahedron in the crystal lattice, thereby increasing the mobility of electrons in the crystal with the perovskite structure and improving the photoelectric conversion efficiency of the photoelectric conversion element.

[0042] The organic-inorganic perovskite compound used in the present invention is preferably a crystalline semiconductor. The crystalline semiconductor means a semiconductor in which the scattering peak can be detected by measuring the X-ray scattering intensity distribution. By using the organic-inorganic perovskite compound as a crystalline semiconductor, the mobility of electrons in the organic-inorganic perovskite compound is increased, and the photoelectric conversion efficiency of the photoelectric conversion element is improved.

[0043] The thickness of the photoelectric conversion layer according to the present invention is preferably 5 nm or more and 2000 nm or less. If the thickness is 5 nm or more, light can be sufficiently absorbed, and if the thickness is 2000 nm or less, the generated charge can be transported to each electrode. The more preferred lower limit is 50 nm or more, the more preferred upper limit is 1200 nm, the even more preferred lower limit is 100 nm, and the even more preferred upper limit is 1000 nm.

[0044] [Charge transport layer] The photoelectric conversion element of the present invention has a charge transport layer between the photoelectric conversion layer and the first electrode. The photoelectric conversion element of the present invention has a charge transport layer containing a P-type semiconductor crystal as a charge transport material and a resin. The photoelectric conversion element of the present invention has a P-type semiconductor crystal having a Lewis basic functional group, more specifically, a functional group that can be a hydrogen bond donor, and further, the P-type semiconductor crystal has at least one functional group selected from the group consisting of a hydroxy group, a carboxy group, an amino group, an imino group, and a sulfo group. These functional groups can be confirmed, for example, by using X-ray photoelectron spectroscopy (XPS) or nuclear magnetic resonance (NMR).

[0045] In the photoelectric conversion element of the present invention, the charge transport layer is preferably in contact with the photoelectric conversion layer, which not only traps ions migrated from the photoelectric conversion layer but also directly interacts with defects on the surface of the perovskite, which is the photoelectric conversion layer, enhancing the effect of preventing carrier recombination.

[0046] In the photoelectric conversion element of the present invention, it is preferable that the P-type semiconductor crystals are dispersed in the resin, which makes it easier for the charge transport material and the resin to come into uniform contact with each other, thereby enabling an effective charge distribution to be formed.

[0047] From the viewpoint of durability of charge transportability, the photoelectric conversion element of the present invention preferably has a content of the P-type semiconductor crystals in a mass ratio of 5 to 30 times the content of the resin in the charge transport layer. The content of the P-type semiconductor crystals and the content of the resin can be confirmed, for example, by using X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS), or the like.

[0048] From the viewpoint of durability, the photoelectric conversion element of the present invention preferably has a thickness of the charge transport layer of 10 nm to 400 nm, more preferably 100 nm to 200 nm. The thickness of the charge transport layer can be confirmed, for example, by observing a cross section of the photoelectric conversion element with a scanning electron microscope (SEM) or a transmission electron microscope (TEM).

[0049] In the photoelectric conversion element of the present invention, the resin is preferably a polyvinyl acetal resin, more preferably a polyvinyl butyral resin. It is likely to come into close contact with the charge transport material, and the ions constituting the perovskite interact with the functional groups of the resin. In the present invention, the chemical substance can be confirmed, for example, by nuclear magnetic resonance (NMR).

[0050] In the photoelectric conversion element of the present invention, from the viewpoint of charge transportability, the P-type semiconductor crystal is preferably a cyclic conjugated compound in which a plurality of pyrrole rings are conjugated. In the present invention, the chemical substance can be confirmed by, for example, nuclear magnetic resonance (NMR).

[0051] The charge transport layer can be formed by preparing a coating solution for the charge transport layer containing the above-mentioned materials and solvent, forming this coating film on the photoelectric conversion layer, and drying it. Examples of the solvent used in the coating solution include alcohol-based solvents, ketone-based solvents, ether-based solvents, thioether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Among these solvents, alcohol-based solvents or aromatic hydrocarbon-based solvents are preferred.

[0052] [Second Charge Transport Layer] The photoelectric conversion element of the present invention may have a second charge transport layer between the first electrode and the charge transport layer. By having the second charge transport layer, the transfer of carriers to the electrode may be facilitated. The material of the second charge transport layer 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, and thiocyanate compounds. In particular, from the viewpoint of compatibility with the film interface, it is preferable that the compound has an aromatic ring, and Spiro-OMeTAD, PTAA, and phthalocyanine compounds are preferable.

[0053] [Electron transport layer] In the photoelectric conversion element of the present invention, as shown in FIG. 1, an electron transport layer 4 may be disposed between the second electrode 3 and the photoelectric conversion layer 5.

[0054] 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, surfactants, and the like. Specific examples thereof include cyano group-containing polyphenylene vinylene, boron-containing polymers, bathocuproine, bathophenanthrene, hydroxyquinolinatoaluminum, oxadiazole compounds, benzimidazole compounds, naphthalene tetracarboxylic acid 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, zinc sulfide, and the like.

[0055] The thickness of the electron transport layer 4 is preferably 1 nm in lower limit and 2000 nm in upper limit. If the thickness is 1 nm or more, holes can be blocked sufficiently, and if the thickness is 2000 nm or less, resistance during electron transport is unlikely to occur, and photoelectric conversion efficiency is increased. The more preferable lower limit of the thickness is 3 nm, the more preferable upper limit is 1000 nm, the even more preferable lower limit is 5 nm, and the even more preferable upper limit is 500 nm.

[0056] <Application Examples> Application examples of the present invention include photoelectric conversion devices, moving objects, and building materials.

[0057] [Photoelectric conversion device] The photoelectric conversion device of the present invention has the above-mentioned photoelectric conversion element. A photoelectric conversion device can be configured by using a plurality of photoelectric conversion elements of the present invention. When a plurality of photoelectric conversion elements are connected, the photoelectric conversion device can also be called a photoelectric conversion cell or a photoelectric conversion module. The photoelectric conversion element may be a stack of photoelectric conversion elements having different absorption wavelengths in order to increase the output voltage. The photoelectric conversion device also has 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 storage unit connected to the photoelectric conversion element. The storage unit is not limited as long as it can store electricity. For example, a secondary battery using lithium ions or the like, an all-solid-state battery, an electric double layer capacitor, etc. can be mentioned.

[0058] [Mobile object] The moving body of the present invention has the above-mentioned photoelectric conversion element. FIG. 2 is a perspective view showing an embodiment of a moving body equipped with the photoelectric conversion element of the present invention. The moving body 30 has the photoelectric conversion element 31 of the present invention and a vehicle 32 equipped with the photoelectric conversion element 31. The photoelectric conversion element 31 is arranged at a position where the vehicle 32 can receive external light. If the moving body 30 is an automobile, it may be arranged on the roof. The electric energy obtained by the photoelectric conversion element 31 may be used as the power of the moving body 30 or as the power of other electric devices. The electric 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 electric energy and used to control the photoelectric conversion element 31.

[0059] The moving body 30 may be, for example, an automobile, a ship, an aircraft, or a drone. The configuration of the body 32 of the moving body 30 is not particularly limited, but it is preferable that the body 32 be made of a high-strength material.

[0060] [Building materials] The building material of the present invention has the above-mentioned photoelectric conversion element. Fig. 3 is a perspective view showing an 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 exteriors 44a and 44b.

[0061] 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, the temperature of the photoelectric conversion element 41 may increase due to sunlight, and the photoelectric conversion efficiency may decrease. The use of the heat dissipation member 43 can reduce the decrease in photoelectric conversion efficiency. Examples of the heat dissipation member 43 include metal, alloy, liquid metal, and liquid resin.

[0062] Furthermore, the building material 40 of the present invention may have exteriors 44a and 44b. The exteriors 44a and 44b may emit different colors or may be the same. 44a and 44b may be made of the same material or different materials. Paint or a transparent substrate may be used as the exterior. A material with low light absorption and high heat insulation is preferable. EXAMPLES

[0063] 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.

[0064] <Preparation of P-type semiconductor crystal particles 1> Process (1) In a nitrogen flow atmosphere, 5.46 parts of orthophthalonitrile and 45 parts of α-chloronaphthalene were added to a reaction vessel, which was then heated to a temperature of 30° C. and maintained at this temperature. Next, 3.75 parts of gallium trichloride were added at this temperature (30° C.). The water concentration of the mixture at the time of addition was 150 ppm.

[0065] The temperature was then raised to 200°C. Next, the mixture was reacted at 200°C for 4.5 hours under a nitrogen flow atmosphere, then cooled, and the product was filtered when the temperature reached 150°C. 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 to obtain chlorogallium phthalocyanine particles in a yield of 71%.

[0066] Process (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 cause reprecipitation, and then filtered under reduced pressure using a filter press, using No. 5C (manufactured by Advantec Co., Ltd.) as the filter.

[0067] The obtained wet cake (filtrate) was dispersed and washed with 2% ammonia water 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 using a filter press three times.

[0068] Finally, freeze-drying was performed to obtain hydroxygallium phthalocyanine particles (hydrated hydroxygallium phthalocyanine particles) with a solid content of 23% by mass at a yield of 71%. These hydroxygallium phthalocyanine particles were dried in a Hyper Dry dryer (product name: HD-06R, frequency (oscillation frequency): 2455 MHz ± 15 MHz, manufactured by Japan Biocon) to obtain hydroxygallium phthalocyanine (OHGaPc) particles (crystals) with a water content of 1.0% by mass or less.

[0069] Process (3) Five parts of the hydroxygallium phthalocyanine particles were mixed with 5 parts of N-methylformamide solvent, and the mixture was dispersed for 6 hours using a sand mill (TSG-1 / 4G-4U, manufactured by Igarashi Machinery Mfg. Co., Ltd. (now Imex), disk diameter 70 mm, number of disks 5) containing 5 parts of glass beads, filtered, and dried to obtain P-type semiconductor crystal particles 1 (specific gravity 1.6).

[0070] Preparation of resin solution 1 A resin solution 1 was obtained by dissolving 1.0 part of polyvinyl butyral resin (product name: S-LEC (registered trademark) BM-2, manufactured by Sekisui Chemical Co., Ltd., specific gravity 1.6) in 19 parts of 2-propanol with stirring for 24 hours.

[0071] Example 1 [Formation of Electron Transport Layer] A square ITO-coated glass substrate with sides of 25 mm was cleaned, and a solution of tin oxide (2) colloidal dispersion diluted with water at a volume ratio of 1 / 7 was spin-coated on the substrate at 5000 rpm for 30 seconds. It was then heated at 150°C for 30 minutes and dried in an outdoor temperature of -20°C and a humid environment to form an electron transport layer.

[0072] [Formation of photoelectric conversion layer] Lead iodide (1.2 M), lead bromide (0.15 M), formamidinium iodide (1.0 M), methylammonium bromide (0.15 M) and cesium iodide (0.13 M) were dissolved in N,N-dimethylformamide:dimethylsulfoxide = 4:1 (volume ratio) to prepare a photoelectric conversion layer coating solution. This coating solution was spin-coated on the electron transport layer at 2700 rpm for 10 seconds and then at 5000 rpm for 20 seconds. Five seconds before the end of spin coating, 150 μL of chlorobenzene was dropped onto the substrate. Finally, the substrate was heated at 130 °C for 15 minutes to obtain Cs 0.1 (MA 0.17 FA 0.83 ) 0.9 Pb(I 0.9 Br 0.1 A photoelectric conversion layer made of 3 was formed.

[0073] [Formation of Charge Transport Layer] 0.1 parts of the P-type semiconductor crystal particles 1 and 0.01 parts of a calixarene compound (see JP 2003-207913 A) were mixed with 10.6 parts of 2-propanol, and 11 parts of beads (zirconia beads, Treceram (registered trademark) zirconia beads, 0.3 mm) were encapsulated in this mixture, and dispersion was performed using a paint shaker (manufactured by Toyo Seiki) for 3 hours. Then, 0.2 parts of resin solution 1 was added, and dispersion was performed again using a paint shaker for 4 hours to prepare a charge transport layer solution. This charge transport layer solution was spin-coated on the photoelectric conversion layer at 1000 rpm for 30 seconds, and heated at 60° C. for 10 minutes to form a charge transport layer having a thickness of about 150 nm.

[0074] [Introduction of a second charge transport layer] 0.08 parts of Spiro-OMeTAD as a material for the second charge transport layer was dissolved in 1.13 parts of chlorobenzene. This chlorobenzene solution was mixed with 0.019 parts of an acetonitrile solution (2M) of lithium bis(trifluoromethanesulfonyl)imide, 0.030 parts of 4-tert-butylpyridine (TBP), and 0.016 parts of an acetonitrile solution (0.25M) of [tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine)cobalt(3) tris(bis(trifluoromethylsulfonyl)imide)] to prepare a material solution for the second charge transport layer. This was applied to the charge transport layer by spin coating at 2000 rpm for 30 seconds to form a second charge transport layer.

[0075] [Formation of the first electrode] On the second charge transport layer, a layer having a thickness of 70 nm and an area of ​​0.09 cm 2 Gold electrodes were formed at 10 locations by vacuum deposition to obtain a photoelectric conversion element.

[0076] [Analysis of compound amounts] The electrode surface of the photoelectric conversion element was peeled off to expose the charge transport layer surface. This charge transport layer surface was wiped with a cotton swab soaked in a solvent, dissolved in heavy water sulfuric acid, and 1H-NMR measurement (apparatus: AVANCE3-500, manufactured by BRUKER) was performed. In addition, the peeled off charge transport layer components were subjected to mass and structure analysis by elemental analysis such as GPC, MALDI-TOF-MS, IR, gas chromatography, XPS, and EDX to confirm the presence of compounds.

[0077] The film thickness was confirmed by cutting the photoelectric conversion element, fixing it to an inclined sample stage, and then examining the cross-section with a SEM (apparatus: Carl Zeiss, SmartSEM).

[0078] Example 2 A photoelectric conversion element is obtained in the same manner as in Example 1, except that the thickness of the charge transport layer is changed to 200 nm.

[0079] Example 3 A photoelectric conversion element is obtained in the same manner as in Example 1, except that the mass ratio of the P-type semiconductor crystal particles 1 to the resin is changed to three times.

[0080] Example 4 A photoelectric conversion element is obtained in the same manner as in Example 1, except that the mass ratio of the P-type semiconductor crystal particles 1 to the resin is changed to 5 times.

[0081] Example 5 A photoelectric conversion element is obtained in the same manner as in Example 1, except that the mass ratio of the P-type semiconductor crystal particles 1 to the resin is changed to 30 times.

[0082] Example 6 A photoelectric conversion element is obtained in the same manner as in Example 1, except that the mass ratio of the P-type semiconductor crystal particles 1 to the resin is changed to 35 times.

[0083] Example 7 A photoelectric conversion element is obtained in the same manner as in Example 1, except that the thickness of the charge transport layer is changed to 89 nm.

[0084] Example 8 A photoelectric conversion element is obtained in the same manner as in Example 1, except that the thickness of the charge transport layer is changed to 300 nm.

[0085] Example 9 A photoelectric conversion element is obtained in the same manner as in Example 1, except that tetraphenylporphyrin (TPP) is used instead of the P-type semiconductor crystal particles 1. Tetraphenylporphyrin (TPP) as the P-type semiconductor crystal particles 1 is crystalline.

[0086] Example 10 A photoelectric conversion element is obtained in the same manner as in Example 1, except that the P-type semiconductor crystal particles 1 are changed to 4,4',4'',4'''-(porphine-5,10,15,20-tetralyl)tetrakis(benzoic acid). 4,4',4'',4'''-(porphine-5,10,15,20-tetralyl)tetrakis(benzoic acid) as the P-type semiconductor crystal particles 1 is crystalline.

[0087] Example 11 A photoelectric conversion element is obtained in the same manner as in Example 1, except that 1-aminoanthraquinone-2-sulfonic acid is used as the P-type semiconductor crystal particles 1. The 1-aminoanthraquinone-2-sulfonic acid used as the P-type semiconductor crystal particles 1 is crystalline.

[0088] Example 12 A photoelectric conversion element is obtained in the same manner as in Example 1, except that the calixarene compound is not used.

[0089] (Example 13) A photoelectric conversion element is obtained in the same manner as in Example 1, except that the second charge transport layer is not provided.

[0090] Example 14 A photoelectric conversion element is obtained in the same manner as in Example 1, except that the resin is poly(3-hexylthiophene-2,5-diyl) (P3HT).

[0091] Example 15 A photoelectric conversion element is obtained in the same manner as in Example 1, except that quinacridone particles are used instead of the P-type semiconductor crystal particles 1. The quinacridone particles used as the P-type semiconductor crystal particles 1 are crystalline.

[0092] Comparative Example 1 In the process of producing the P-type semiconductor crystal particles 1, step (3) was not performed, and P-type semiconductor particles 2 that had not undergone crystal conversion were obtained. A photoelectric conversion element was obtained in the same manner as in Example 1, except that in forming the charge transport layer, the P-type semiconductor particles 2 were used instead of the P-type semiconductor crystal particles 1. The P-type semiconductor particles 2 that had not undergone crystal conversion were amorphous.

[0093] Comparative Example 2 A photoelectric conversion element is obtained in the same manner as in Example 1, except that the P-type semiconductor crystal particles 1 are copper phthalocyanine particles.

[0094] Comparative Example 3 A photoelectric conversion element is obtained in the same manner as in Example 1, except that the resin is not used.

[0095] Comparative Example 4 A photoelectric conversion element is obtained in the same manner as in Example 1, except that the P-type semiconductor crystal particles 1 are SPIRO-OMeTAD and the polyvinyl butyral is polymethyl methacrylate (PMMA, manufactured by Sigma-Aldrich).

[0096] [evaluation] A power supply (KEITHLEY, Model 236) was connected between the electrodes of the photoelectric conversion element prepared in Example 1, and the intensity was 110 mW / cm 2The photoelectric conversion efficiency was measured by irradiating a certain amount of light using a solar simulator (manufactured by Yamashita Denso Co., Ltd.) and measuring the generated current and voltage. Measurements were also performed at 10 electrodes for each element, and the maximum value was taken as the representative value for that element. After that, 10,000 Lx of light was continuously irradiated from a white LED, and the photoelectric conversion efficiency after 60 days was measured. The durability was evaluated by evaluating the maintenance rate of the photoelectric conversion efficiency after 60 days relative to the initial photoelectric conversion efficiency obtained. The results are shown in Table 2 together with the initial photoelectric conversion efficiency.

[0097] Examples 2 to 15 and Comparative Examples 1 to 4 are also evaluated in terms of the initial photoelectric conversion efficiency and the maintenance rate of the photoelectric conversion efficiency after 60 days in the same manner as in Example 1. The results are shown in Table 2.

[0098] [Table 2]

[0099] The disclosure of this embodiment includes the following configuration. (Configuration 1) A photoelectric conversion element having a first electrode, a second electrode, and a photoelectric conversion layer including a crystal having a perovskite structure and disposed between the first electrode and the second electrode, the photoelectric conversion element has a charge transport layer between the photoelectric conversion layer and the first electrode, the charge transport layer includes a P-type semiconductor crystal and a resin, A photoelectric conversion element, wherein the P-type semiconductor crystal has at least one functional group selected from the group consisting of a hydroxy group, a carboxy group, an amino group, an imino group, and a sulfo group. (Configuration 2) A photoelectric conversion element having a first electrode, a second electrode, and a photoelectric conversion layer including a crystal having a perovskite structure and disposed between the first electrode and the second electrode, the photoelectric conversion element has a charge transport layer between the photoelectric conversion layer and the first electrode, the charge transport layer includes a P-type semiconductor crystal and a resin, A photoelectric conversion element, wherein the P-type semiconductor crystal has a functional group capable of acting as a hydrogen bond donor. (Configuration 3) A photoelectric conversion element having a first electrode, a second electrode, and a photoelectric conversion layer including a crystal having a perovskite structure and disposed between the first electrode and the second electrode, the photoelectric conversion element has a charge transport layer between the photoelectric conversion layer and the first electrode, the charge transport layer includes a P-type semiconductor crystal and a resin, A photoelectric conversion element, wherein the P-type semiconductor crystal has a Lewis basic functional group. (Configuration 4) The photoelectric conversion element according to any one of configurations 1 to 3, wherein the charge transport layer is in contact with the photoelectric conversion layer. (Configuration 5) 5. The photoelectric conversion element according to any one of configurations 1 to 4, wherein the charge transport layer has the P-type semiconductor crystals dispersed in the resin. (Configuration 6) The photoelectric conversion element according to any one of configurations 1 to 5, wherein the content of the P-type semiconductor crystal in the charge transport layer is 5 to 30 times, in terms of mass ratio, the content of the resin in the charge transport layer. (Configuration 7) 7. The photoelectric conversion element according to any one of configurations 1 to 6, wherein the charge transport layer has a thickness of 10 nm or more and 400 nm or less. (Configuration 8) 7. The photoelectric conversion element according to any one of configurations 1 to 6, wherein the charge transport layer has a thickness of 100 nm or more and 200 nm or less. (Configuration 9) The photoelectric conversion element according to any one of configurations 1 to 8, further comprising a second charge transport layer between the first electrode and the charge transport layer. (Configuration 10) 10. The photoelectric conversion element according to any one of configurations 1 to 9, wherein the resin is a polyvinyl acetal resin. (Configuration 11) 4. The photoelectric conversion element according to any one of configurations 1 to 3, wherein the P-type semiconductor crystal is a cyclic conjugated compound formed by conjugating a plurality of pyrrole rings. (Configuration 12) A photoelectric conversion device comprising the photoelectric conversion element according to any one of configurations 1 to 11. (Configuration 13) A moving object having the photoelectric conversion element according to any one of configurations 1 to 11. (Configuration 14) A building material comprising the photoelectric conversion element according to any one of configurations 1 to 11. [Explanation of symbols]

[0100] 1 Photoelectric conversion element 2. Board 3 Second electrode 4 Electron transport layer 5 Photoelectric conversion layer 6 Charge transport layer 7 First electrode 8 Second Charge Transport Layer 30 Mobile 31, 41 Photoelectric conversion element 32 Aircraft 40 Building materials 42 Protective materials 43 Heat dissipation materials 44a, 44b Exterior

Claims

1. A photoelectric conversion element having a first electrode, a second electrode, and a photoelectric conversion layer including a crystal having a perovskite structure and disposed between the first electrode and the second electrode, the photoelectric conversion element has a charge transport layer between the photoelectric conversion layer and the first electrode, the charge transport layer includes a P-type semiconductor crystal and a resin, the P-type semiconductor crystal has at least one functional group selected from the group consisting of a hydroxy group, a carboxy group, an amino group, an imino group, and a sulfo group; A photoelectric conversion element comprising:

2. A photoelectric conversion element having a first electrode, a second electrode, and a photoelectric conversion layer including a crystal having a perovskite structure and disposed between the first electrode and the second electrode, the photoelectric conversion element has a charge transport layer between the photoelectric conversion layer and the first electrode, the charge transport layer includes a P-type semiconductor crystal and a resin, The P-type semiconductor crystal has a functional group capable of acting as a hydrogen bond donor. A photoelectric conversion element comprising:

3. A photoelectric conversion element having a first electrode, a second electrode, and a photoelectric conversion layer including a crystal having a perovskite structure and disposed between the first electrode and the second electrode, the photoelectric conversion element has a charge transport layer between the photoelectric conversion layer and the first electrode, the charge transport layer includes a P-type semiconductor crystal and a resin, The P-type semiconductor crystal has a Lewis basic functional group. A photoelectric conversion element comprising:

4. 4. The photoelectric conversion element according to claim 1, wherein the charge transport layer is in contact with the photoelectric conversion layer.

5. 4. The photoelectric conversion element according to claim 1, wherein the charge transport layer has the P-type semiconductor crystals dispersed in the resin.

6. The photoelectric conversion element according to any one of claims 1 to 3, wherein the content of the P-type semiconductor crystal in the charge transport layer is 5 times or more and 30 times or less, in terms of mass ratio, relative to the content of the resin in the charge transport layer.

7. 4. The photoelectric conversion element according to claim 1, wherein the charge transport layer has a thickness of 10 nm or more and 400 nm or less.

8. 4. The photoelectric conversion element according to claim 1, wherein the charge transport layer has a thickness of 100 nm or more and 200 nm or less.

9. 4. The photoelectric conversion element according to claim 1, further comprising a second charge transport layer between the first electrode and the charge transport layer.

10. 4. The photoelectric conversion element according to claim 1, wherein the resin is a polyvinyl acetal resin.

11. 4. The photoelectric conversion element according to claim 1, wherein the P-type semiconductor crystal is a cyclic conjugated compound formed by conjugating a plurality of pyrrole rings.

12. A photoelectric conversion device comprising the photoelectric conversion element according to any one of claims 1 to 3.

13. A moving object comprising the photoelectric conversion element according to any one of claims 1 to 3.

14. A building material comprising the photoelectric conversion element according to any one of claims 1 to 3.

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