Photoelectric conversion element, photoelectric conversion device, moving object, and building material

Abstract

The present invention addresses the problem of providing a photoelectric conversion element (1) having improved durability and photoelectric conversion efficiency thereof. In order to solve the above problem, the present invention comprises a photoelectric conversion element (1) comprising: a first electrode (7); a second electrode (3); and a photoelectric conversion layer (5) disposed between the first electrode (7) and the second electrode (3), the photoelectric conversion layer containing a crystal having a perovskite structure. The photoelectric conversion element (1) is characterized in that the photoelectric conversion element (1) comprises a charge transport layer (6) between the photoelectric conversion layer (5) and the first electrode (7); the charge transport layer (6) is provided with a P-type semiconductor crystal and resin; and the P-type semiconductor crystal contains at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, an imino group, and a sulfo group.

Description

Technical Field

[0001] This invention relates to photoelectric conversion elements, photoelectric conversion devices, mobile bodies, and building materials. Background Technology

[0002] To address the depletion of fossil fuels and the environmental problems caused by their use, research is actively underway on renewable and clean alternative energy sources such as solar, wind, and hydropower. In particular, there is increasing interest in solar cells, which directly convert sunlight into electricity. As used in this paper, "solar cell" refers to a battery that generates current and voltage using the photovoltaic effect, in which light energy is absorbed from sunlight to produce electrons and holes.

[0003] Currently, NP diode-based monocrystalline silicon (Si) solar cells with a light conversion efficiency exceeding 20% ​​are widely known and practically used in solar power generation. However, solar cells require high-temperature processing steps, and the materials themselves are expensive, resulting in high cost per unit of electricity. Furthermore, there are supply issues regarding silicon resources.

[0004] Meanwhile, solar cells using organic materials (hereinafter also referred to as "organic solar cells") do not require high-temperature processing steps and can be manufactured using sheet substrates in a so-called roll-to-roll manner. Therefore, cost reduction is expected. However, for the practical application of organic solar cells, further improvements in power generation efficiency and durability are desired. In particular, the development of perovskite-type solar cells, which incorporate crystals with a perovskite structure as the photoelectric conversion layer, is being promoted for practical application because these cells exhibit excellent photoelectric conversion characteristics.

[0005] For example, Patent Document 1 describes a technique that incorporates an organic semiconductor and a polymer compound with a glass transition temperature of 100°C or higher into a hole transport layer to improve the layer's peeling off from the electrode. Non-Patent Document 1 describes an improvement in conversion efficiency by mixing copper phthalocyanine and a conductive polymer into the hole transport layer.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2018-170382

[0009] Non-patent literature

[0010] Non-patent literature 1: Q. Hu, et al, Sol. RRL, 2019, 3, 1800264 Summary of the Invention

[0011] The problem the invention aims to solve

[0012] According to research conducted by the inventors of this invention, it has been found that the photoelectric conversion elements described in Patent Document 1 and Non-Patent Document 1 still have room for improvement in terms of durability and photoelectric conversion efficiency.

[0013] Therefore, the present invention aims to provide a photoelectric conversion element with improved durability and photoelectric conversion efficiency. The present invention also aims to provide a photoelectric conversion device.

[0014] Solution for solving the problem

[0015] This invention relates to a photoelectric conversion element, comprising:

[0016] A first electrode; a second electrode; and a photoelectric conversion layer disposed between the first electrode and the second electrode, the photoelectric conversion layer containing crystals having a perovskite structure.

[0017] The photoelectric conversion element includes a charge transport layer between the photoelectric conversion layer and the first electrode.

[0018] The charge transport layer contains a P-type semiconductor crystal and a resin, and

[0019] The P-type semiconductor crystal has at least one functional group selected from the group consisting of hydroxyl, carboxyl, amino, imino and sulfonyl groups.

[0020] The present invention also relates to a photoelectric conversion element comprising:

[0021] A first electrode; a second electrode; and a photoelectric conversion layer disposed between the first electrode and the second electrode, the photoelectric conversion layer containing crystals having a perovskite structure.

[0022] The photoelectric conversion element includes a charge transport layer between the photoelectric conversion layer and the first electrode.

[0023] The charge transport layer contains a P-type semiconductor crystal and a resin, and

[0024] The P-type semiconductor crystal has functional groups that can act as hydrogen bond donors.

[0025] The present invention also relates to a photoelectric conversion element comprising:

[0026] A first electrode; a second electrode; and a photoelectric conversion layer disposed between the first electrode and the second electrode, the photoelectric conversion layer containing crystals having a perovskite structure.

[0027] The photoelectric conversion element includes a charge transport layer between the photoelectric conversion layer and the first electrode.

[0028] The charge transport layer contains a P-type semiconductor crystal and a resin, and

[0029] The P-type semiconductor crystal has Lewis basic functional groups.

[0030] The present invention also relates to a photoelectric conversion device comprising the above-mentioned photoelectric conversion element.

[0031] The present invention also relates to a mobile body comprising the above-described photoelectric conversion element.

[0032] The present invention also relates to a building material comprising the above-mentioned photoelectric conversion element.

[0033] The effects of the invention

[0034] According to the present invention, a photoelectric conversion element with improved durability and photoelectric conversion efficiency can be provided. Attached Figure Description

[0035] [ Figure 1 This is a schematic diagram of the layer structure in the thickness direction of a photoelectric conversion element according to an embodiment of the present invention.

[0036] [ Figure 2 [A perspective view of a moving body including a photoelectric conversion element according to an embodiment of the present invention is shown for illustrative purposes.]

[0037] [ Figure 3 [A perspective view of a building material comprising a photoelectric conversion element according to an embodiment of the present invention is shown schematically.] Detailed Implementation

[0038] <An Implementation Plan>

[0039] One implementation involves a photoelectric conversion element.

[0040] The photoelectric conversion element of the present invention includes a first electrode, a second electrode, and a photoelectric conversion layer disposed between the first electrode and the second electrode. The photoelectric conversion layer contains a crystal having a perovskite structure. The photoelectric conversion element is characterized in that a charge transport layer is included between the photoelectric conversion layer and the first electrode. The charge transport layer contains 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 hydroxyl, carboxyl, amino, imino, and sulfonyl groups.

[0041] Furthermore, the photoelectric conversion element of the present invention includes a first electrode, a second electrode, and a photoelectric conversion layer disposed between the first electrode and the second electrode, the photoelectric conversion layer containing a crystal having a perovskite structure, and is characterized in that the photoelectric conversion element includes a charge transport layer between the photoelectric conversion layer and the first electrode, the charge transport layer containing a P-type semiconductor crystal and a resin, and the P-type semiconductor crystal having a functional group that can act as a hydrogen bond donor.

[0042] Furthermore, the photoelectric conversion element of the present invention includes a first electrode, a second electrode, and a photoelectric conversion layer disposed between the first electrode and the second electrode, the photoelectric conversion layer containing a crystal having a perovskite structure, and is characterized in that the photoelectric conversion element includes a charge transport layer between the photoelectric conversion layer and the first electrode, the charge transport layer containing a P-type semiconductor crystal and a resin, and the P-type semiconductor crystal having Lewis basic functional groups.

[0043] As a result of the research, the inventors have discovered that by including the aforementioned charge transport layer, a photoelectric conversion element with excellent durability and conversion efficiency can be provided. The reasoning is speculated as follows.

[0044] The perovskite surface contains several types of defects, such as poorly coordinated Pb. 2+ Ions, Pb clusters, iodine vacancies, organic A cation vacancies, and insufficiently coordinated I - Ions. These surface defects can cause recombination of electrons and holes via non-radiative channels, which may lead to the degradation of the photoelectric conversion element or a decrease in its conversion efficiency. Furthermore, in perovskite solar cells, external water molecules or ions and molecules used to form the photoelectric conversion element may migrate to other layers, disrupting the structure of the photoelectric conversion element.

[0045] In contrast, it is hypothesized that when the charge transport layer in contact with the photoelectric conversion layer contains a P-type semiconductor crystal with Lewis basic functional groups or functional groups that can act as hydrogen bond donors, it is possible to prevent a decrease in the durability and conversion efficiency of the photoelectric conversion element. Factors contributing to this prevention include, for example, the passivation of defects in Lewis acids present on the perovskite surface through interaction with Lewis bases; and insufficient coordination of I0.05... - Ions are captured by hydrogen atoms contained in the functional groups. Furthermore, defects in crystals with a perovskite structure extend from tens of nanometers to hundreds of nanometers. Therefore, it has been found that including such a charge transport layer contributes to improved durability and conversion efficiency of the photoelectric conversion element, even when a hole transport layer or insulating layer of tens of nanometers is introduced between the charge transport layer and the photoelectric conversion layer of the present invention.

[0046] Furthermore, it is speculated that when a P-type semiconductor crystal and resin are included in the charge transport layer, defects on the perovskite surface that cannot be covered by the P-type semiconductor crystal alone interact with the functional groups of the resin. Moreover, the P-type semiconductor crystal, with its high charge transport and high hole mobility, does not hinder charge transport even when the crystal is contained within a thick film. However, when resin is further included in the charge transport layer, the photoelectric conversion layer can be reliably covered, and durability can be enhanced while maintaining charge transport.

[0047] When the various components work together synergistically through the above-described mechanism, the effects of this invention can be achieved.

[0048] The present invention will be described in detail below by way of preferred embodiments. The present invention is not limited to the following embodiments, and appropriate changes and modifications to the following embodiments based on ordinary knowledge of those skilled in the art, without departing from the spirit of the invention, are also included within the scope of the present invention.

[0049] As used herein, the term "layer" refers not only to a layer with clearly defined boundaries or a flat, thin-film shape, but also to a layer with a concentration gradient in which the concentration of elements varies gradually, or a layer that can form a complex, interwoven structure with other layers. Furthermore, elemental analysis of layers can be performed, for example, by TOF-SIMS / FE-TEM / EDS line analysis of a cross-section of a photoelectric conversion element to determine the elemental distribution of specific elements. Analysis of individual layers can be performed by peeling and removing the layers from the completed element to expose the layer to be analyzed. For quantification of volume ratios, the area ratio of the exposed surface or cross-section can be used as the volume ratio of the layers.

[0050] Figure 1 This is a schematic cross-sectional view illustrating the configuration of a photoelectric conversion element according to one embodiment of the present invention. The photoelectric conversion element 1 includes a substrate 2 and a second electrode 3, an electron transport layer 4, a photoelectric conversion layer 5, a charge transport layer 6, and a first electrode 7 disposed thereon. One of the first electrode 7 and the second electrode 3 is a positive electrode, and the other is a negative electrode. By connecting the first electrode 7 and the second electrode 3 to an external circuit, current can be extracted.

[0051] The photoelectric conversion layer 5 is excited by light passing 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, to generate 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 disposed between the photoelectric conversion layer 5 and the two electrodes (the second electrode 3 and the first electrode 7), and in some cases, it may not be formed. A configuration in which multiple electron transport layers 4 and photoelectric conversion layers 5 are stacked can be adopted. This configuration can also be called a "tandem structure." The components are described below. Furthermore, a photoelectric conversion element can 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.

[0052] [Photoelectric conversion element]

[0053] The photoelectric conversion element of the present invention is characterized by comprising: a first electrode; a second electrode; and a photoelectric conversion layer disposed between the first electrode and the second electrode, the photoelectric conversion layer containing a crystal having a perovskite structure. Furthermore, to improve photoelectric conversion efficiency, a series configuration in which the photoelectric conversion elements are stacked can also be used. There are no limitations on the type of photoelectric conversion element stacked; for example, in addition to perovskite solar cells using perovskite crystals in the photoelectric conversion layer, silicon solar cells or CIGS solar cells can also be used.

[0054] The methods for forming the layers of the photoelectric conversion element of the present invention include, for example, coating methods and vapor deposition methods. Examples of coating methods include dip coating, spin coating, spray coating, inkjet coating, meniscus coating, screen coating, roll coating, die coating, doctor blade coating, curtain coating, and wire rod coating. A coating method includes preparing a coating liquid for each layer described below, applying the liquid in the desired layer sequence, and drying the liquid. As such film-forming methods, the desired method is selected according to each layer.

[0055] The following section describes each layer.

[0056] [Substrate]

[0057] The photoelectric conversion element 1 of the present invention may include a substrate 2, examples of which include a transparent glass substrate, a ceramic substrate, and a transparent plastic substrate made of soda-lime glass or alkali-free glass. When light is taken in from the side of the first electrode 7, an opaque material may be used as the substrate 2, and when light is taken in from the side of the second electrode 3, the substrate 2 is formed of a transparent material.

[0058] [electrode]

[0059] There are no particular restrictions on the materials used for the first electrode 7 or the second electrode 3; materials known to date may be used. Examples include: metals such as gold, silver, titanium, and copper; sodium; sodium-potassium alloys; lithium; magnesium; carbon; aluminum; magnesium-silver mixtures; magnesium-indium mixtures; aluminum-lithium alloys; Al / Al2O3 mixtures; and Al / LiF mixtures.

[0060] Examples of transparent electrode materials include conductive transparent materials such as CuI, indium tin oxide (ITO), SnO2, zinc aluminum oxide (AZO), indium zinc oxide (IZO), zinc gallium oxide (GZO), fluorine-doped tin oxide (FTO), and antimony-doped tin oxide (ATO); as well as conductive transparent polymers.

[0061] These materials can be used alone or in combination. At least one of the first electrode 7 or the second electrode 3 on the light incident side is a transparent electrode, and the other can be a transparent electrode or act as a reflective layer formed of a light-reflective material, or it can be a transparent electrode contained in 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 and the substrate 2 can be a transparent electrode and a reflective layer, respectively. The electrodes can be patterned electrodes.

[0062] [Photoelectric conversion layer]

[0063] The photoelectric conversion layer 5 comprises a crystal with a perovskite structure. The crystal with a perovskite structure used in this invention is preferably represented by the following general formula [1].

[0064] ABX3 [1]

[0065] In the general formula [1], A represents a monovalent cation of an organic molecule or metal atom, B represents a divalent metal cation, and X represents a monovalent halide anion.

[0066] In general formula [1], A preferably represents C in the case of organic molecules, for example. p N q H r ("p", "q", and "r" each represent a positive integer). Specific examples include methylammonium and formamidinium.

[0067] Furthermore, there are no particular restrictions on the metal atoms, with lithium, cesium, sodium, potassium, and rubidium being preferred. These organic molecules or metal atoms can be used alone or in combination.

[0068] When the contained cation A is too large to fit into a crystal with a 3D perovskite structure, it forms a crystal with a 2D perovskite structure, a crystal with a 2.5D perovskite structure that has the properties of both 2D and 3D perovskite structures, a two-layer crystal with 3D and 2D perovskite structures, or a crystal with a mixed 3D / 2D perovskite structure. Any of these structures can function as a photoelectric conversion layer.

[0069] Two-layered crystals with 3D and 2D perovskite structures refer to crystals with 3D and 2D perovskite structures stacked as independent and separate layers. Crystals with mixed 3D / 2D perovskite structures refer to crystals with the following structure: regions or domains of crystals with 2D or 2.5D layered and 3D perovskite structures are mixed.

[0070] Preferably, crystals having a 2D perovskite or 2.5D perovskite structure are represented by the following general formulas [2] to [4] ("n" represents a positive integer).

[0071] R′2A n-1 B n X 3n+1 [2]

[0072] R″A n-1 B n X 3n+1 [3]

[0073] R″′A n B n X 3n+1 [4]

[0074] General formulas [2], [3] and [4] form Ruddlesden-Popper (RP), Dion-Jacobson (DJ) and interlayer alternating cation (ACI) perovskite structures, respectively.

[0075] In general formulas [2] to [4], R′, R″, and R″′ each represent an organic molecule or metal that may have substituents. Specifically, ethylammonium, propylammonium, n-butylammonium, n-hexylammonium, n-octylammonium, 1,6-hexammonium diammonium, isobutylammonium, 3-(nonafluoro-tert-butoxy)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, pyrrolidineonium, cyclohexylammonium, 4-fluoro Phenethylammonium, 4-fluorophenylethylammonium, trifluoromethylbenzylammonium, pentafluorobenzylammonium, pentafluorophenylethylammonium, 4-methoxyphenylethylammonium, imidazolium, pyridinium, 3-thiophenemethylammonium, 2-thiopheneethylammonium, 2-thiopheneformamidinium, 2-thiophenemethylammonium, 1-naphthylmethylammonium, 2-naphthylmethylammonium, phenethylammonium, phenylammonium, benzylammonium, 2,5-thiophenedimethylammonium, phenylpropylammonium, 1,4-phenylenediamine, 3-phenyl-2-propen-1-ammonium, phenylbutylammonium, 4-tert-butylbenzylammonium, 3-(aminomethyl)piperidinium, and 4-(aminomethyl)piperidinium are preferred.

[0076] In each of the general formulas [1] to [4], B represents a metal atom, examples of which include lead, tin, bismuth, zinc, titanium, antimony, nickel, iron, cobalt, silver, copper, gallium, germanium, magnesium, calcium, indium, aluminum, manganese, chromium, molybdenum, and europium. Among these, lead, tin, and bismuth are preferred from the viewpoint of electron orbital overlap. These metal atoms can be used individually or in combination.

[0077] In each of the general formulas [1] to [4], X represents a halogen atom, examples of which include chlorine, bromine, and iodine. These halogen atoms can be used alone or in combination. Halogen atoms are preferred because when the structure contains halogen atoms, the crystals with the perovskite structure described above become readily soluble in organic solvents, thereby enabling their application in inexpensive printing methods, etc. Iodine is even more preferred because the energy band gap of crystals with the perovskite structure is narrowed.

[0078] Specifically, MAPbI3, FAPbCl3, FAPbI3, and MAPbI are 3D perovskites, 2D perovskites, and mixed 3D / 2D perovskites. 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. Cs0.05 (MA 0.17 FA 0.83 ) 0.95 Pb(I 0.83 Br 0.17 )3、{Cs x1 (FA x2 MA 1-x2 ) 1-x1} x3 Pb(I x4 Br 1-x4 ) x5 、Cs 0.05 FA 0.88 MA 0.07 PbI 2.56 Br 0.44 、(FAPbI3) 0.95 (MAPbBr3) 0.05 、(FAPbI3) 0.85 (MAPbBr3) 0.15 、CsPbI3、CsPbBr3、Cs x (MA) 1-x PbI3、Cs x (FA) 1-x PbI3、MA x (FA) 1-x PbI3、MA 0.17 FA 0.83 Pb(I 0.83 Br 0.17 )3、Cs 0.15 FA 0.85 PbI 2.55 Br 0.45 、Cs 0.05 FA 0.88 MA 0.07 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 )4Pb5I16 (PDMA)FA2Pb3I 10 (3AMPY)(MA)3Pb4I 13 (PDMA)MA5Pb6I 19 (PDMA)MA3Pb4I 13 (TTDMA)MA3Pb4I 13 (TTDMA)MA4Pb5I 16 、(BA 0.9 PEA 0.1 )2MA4Pb5I 16 、(BA 0.9 PEA 0.1 )2MA3Pb4I 13 (4FPEA)2MA3Pb4I 13 (4FPEA)2MA4Pb5I 16 (BA)2MA2Pb3I 10 (BA)2MA3Pb4I 13 (TEA)2MA2Pb3I 10 (BA)2MA4Pb5I 16 and (BA)2MA3Pb4I 13 It is the preferred option.

[0079] The number of A, B, or X positions in each general formula can be adjusted to be too few or too many depending on the purpose, and the combination of x1 to x5 can be changed according to 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 can be included as a material for forming perovskite crystals.

[0080] [Table 1]

[0081] Table 1

[0082]

[0083] In the specific examples above, "MA" represents methylammonium, "FA" represents formamidinium, "PEA" represents phenylethylammonium, "PTA" represents phenyltriethylammonium, "ThMA" represents 2-thiophenemethylammonium, "3BBA" represents 3-bromobenzylammonium, "3AMPY" represents 3-(aminomethyl)pyridine, "PDMA" represents 1,4-phenylenediamine, "TTDMA" represents thieno[3,2-b]thiophene-2,5-dimethylammonium, "4FPEA" represents 4-fluorophenylethylammonium, "BA" represents butylammonium, and "TEA" represents 2-thiopheneethylammonium.

[0084] The aforementioned perovskite-structured crystals preferably have a cubic crystal structure in which metal atoms B, organic molecules A, and halogen atoms X are respectively positioned at the body center, vertices, and face centers. While the details are unclear, it is speculated that the orientation of the octahedrons within the crystal lattice can be easily altered when such a structure exists, thus increasing the electron mobility in the perovskite-structured crystal and improving the photoelectric conversion efficiency of the photoelectric conversion element.

[0085] The organic-inorganic perovskite compound used in this invention is preferably a crystalline semiconductor. The term "crystalline semiconductor" refers to a semiconductor capable of measuring the intensity distribution of X-ray scattering to detect scattering peaks. When the organic-inorganic perovskite compound is a crystalline semiconductor, the electron mobility in the compound increases, and the photoelectric conversion efficiency of the photoelectric conversion element is improved.

[0086] The thickness of the photoelectric conversion layer according to the present invention is preferably 5 nm or more and 2,000 nm or less. When the thickness is 5 nm or more, sufficient light absorption is possible, and when the thickness is 2,000 nm or less, the generated charge can be transported to each electrode. More preferably, the lower limit is 50 nm or more, more preferably, the upper limit is 1,200 nm, even more preferably, the lower limit is 100 nm, and even more preferably, the upper limit is 1,000 nm.

[0087] [charge transport layer]

[0088] The photoelectric conversion element of the present invention includes a charge transport layer between the photoelectric conversion layer and the first electrode. In the photoelectric conversion element of the present invention, the charge transport layer contains a P-type semiconductor crystal as a charge transport material and a resin. In the photoelectric conversion element of the present invention, the P-type semiconductor crystal has Lewis basic functional groups. Furthermore, the P-type semiconductor crystal has functional groups that can act as hydrogen bond donors. Even further, the P-type semiconductor crystal has at least one functional group selected from the group consisting of hydroxyl, carboxyl, amino, imino, and sulfonyl groups. These functional groups can be identified by, for example, X-ray photoelectron spectroscopy (XPS) or nuclear magnetic resonance (NMR).

[0089] In the photoelectric conversion element of the present invention, it is preferable that the charge transport layer is in contact with the photoelectric conversion layer. The charge transport layer not only captures ions migrating from the photoelectric conversion layer, but also interacts directly with defects on the perovskite surface that serves as the photoelectric conversion layer, thereby enhancing the effect of preventing carrier recombination.

[0090] In the photoelectric conversion element of the present invention, it is preferable that a P-type semiconductor crystal is dispersed in the resin. The charge transport material and the resin can easily and uniformly come into contact with each other, thereby forming an effective charge distribution.

[0091] From the viewpoint of maintaining charge transport properties, in the photoelectric conversion element of the present invention, the content of the P-type semiconductor crystal is preferably 5 times or more and 30 times or less by mass relative to the content of the resin in the charge transport layer. The content of the P-type semiconductor crystal and the content of the resin can be determined by, for example, X-ray photoelectron spectroscopy (XPS) or energy-dispersive spectroscopy (EDS).

[0092] From the viewpoint of the durability of the photoelectric conversion element, in the photoelectric conversion element of the present invention, the thickness of the charge transport layer is preferably 10 nm or more and 400 nm or less, more preferably 100 nm or more and 200 nm or less. The thickness of the charge transport layer can be determined, for example, by observing the cross-section of the photoelectric conversion element using a scanning electron microscope (SEM) or a transmission electron microscope (TEM).

[0093] In the photoelectric conversion element of the present invention, the resin is preferably polyvinyl acetal resin, more preferably polyvinyl butyral resin. It is presumed that the resin readily comes into close contact with the charge transport material, and that the functional groups of the resin interact with ions used to form perovskites. In the present invention, the chemical substances can be identified, for example, by nuclear magnetic resonance (NMR).

[0094] From the viewpoint of charge transport, in the photoelectric conversion element of the present invention, the P-type semiconductor crystal is preferably a cyclic conjugated compound in which a plurality of pyrrole rings are linked by conjugated bonds. In the present invention, the chemical substance can be identified, for example, by nuclear magnetic resonance (NMR).

[0095] The charge transport layer can be formed by: preparing a coating solution containing the aforementioned materials and solvents, forming a coating film of the coating solution on the photoelectric conversion layer, and drying the coating film. Examples of solvents used for 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.

[0096] [Second charge transport layer]

[0097] The photoelectric conversion element of the present invention may include a second charge transport layer between the first electrode and the charge transport layer. When the photoelectric conversion element includes a second charge transport layer, it can facilitate the transfer of charge carriers to the electrode.

[0098] There are no particular limitations on the material of the second charge transport layer, and examples include spirofluorene compounds, triphenylamine compounds, phenylene compounds, pyrene compounds, phthalocyanine compounds, carbazole compounds, fluorene compounds, phenylcyclohexane compounds, benzidine compounds, phenoxazine compounds, phenylenediamine compounds, and thiocyanate compounds. From the viewpoint of membrane interface compatibility, the compounds preferably have aromatic rings, and Spiro-OMeTAD, PTAA, or phthalocyanine compounds are particularly preferred.

[0099] [Electron transport layer]

[0100] In the photoelectric conversion element of the present invention, such as Figure 1 As shown, an electron transport layer 4 can be disposed between the second electrode 3 and the photoelectric conversion layer 5.

[0101] There are no particular limitations on the materials used for electron transport layer 4, and examples 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 include cyano-containing polyphenylene vinylidenes, boron-containing polymers, copper bath compounds, phenanthroline, aluminum hydroxyquinoline, oxadiazole compounds, benzimidazole compounds, naphthalenetetracarboxylic acid compounds, perylene derivatives, phosphine oxide compounds, phosphine sulfide compounds, fluorine-containing phthalocyanines, titanium dioxide, zinc oxide, indium oxide, tin oxide, gallium oxide, tin sulfide, indium sulfide, and zinc sulfide.

[0102] The preferred lower limit for the thickness of the electron transport layer 4 is 1 nm, and the preferred upper limit is 2,000 nm. When the thickness is above 1 nm, holes can be sufficiently blocked, and when the thickness is below 2,000 nm, the electron transport layer 4 is unlikely to act as a resistor during electron transport, thus improving the photoelectric conversion efficiency. A more preferred lower limit for the thickness is 3 nm, a more preferred upper limit is 1,000 nm, a still more preferred lower limit is 5 nm, and a still more preferred upper limit is 500 nm.

[0103] <Application Example>

[0104] Applications of this invention relate to photoelectric conversion devices, mobile bodies, and building materials.

[0105] Photoelectric conversion equipment

[0106] The photoelectric conversion device of the present invention includes the aforementioned photoelectric conversion element. A photoelectric conversion device can be formed 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 battery" or a "photoelectric conversion module". Photoelectric conversion elements with different absorption wavelengths can be stacked as photoelectric conversion elements to improve the output voltage. Furthermore, the photoelectric conversion device includes the photoelectric conversion element of the present invention and an inverter. The inverter can be a converter that converts DC voltage to AC voltage. The photoelectric conversion device can include a power storage unit connected to the photoelectric conversion element. There are no limitations on the power storage unit, as long as the power storage unit is capable of storing electricity. Examples include secondary batteries using lithium ions, all-solid-state batteries, and double-layer capacitors.

[0107] [Moving Object]

[0108] The mobile body of the present invention includes the above-described photoelectric conversion element. Figure 2 This is a schematic perspective view of a mobile body including a photoelectric conversion element according to an embodiment of the present invention. The mobile body 30 includes the photoelectric conversion element 31 of the present invention and a body 32 housing the photoelectric conversion element 31. The photoelectric conversion element 31 is disposed at a position on the body 32 capable of receiving ambient light. When the mobile body 30 is a vehicle, the photoelectric conversion element 31 may also be disposed on the roof. The electrical energy obtained through the photoelectric conversion element 31 can serve as the power source for the mobile body 30 or any other electrical device. The electrical energy generated by the power source of the mobile body 30 can be used to power the photoelectric conversion element 31. When the mobile body 30 is a vehicle, the frictional energy generated by braking can be converted into electrical energy for the control of the photoelectric conversion element 31.

[0109] The mobile body 30 can be, for example, a car, a ship, an airplane, or a drone. There are no particular restrictions on the composition of the fuselage 32 of the mobile body 30, but it is preferred to be formed of a material with high strength.

[0110] [Building Materials]

[0111] The building material of the present invention includes the above-mentioned photoelectric conversion element. Figure 3 This is a perspective view schematically illustrating a building material comprising a photoelectric conversion element according to an embodiment of the present invention. Building material 40 may be the roof of a building. Building material 40 of this embodiment comprises the photoelectric conversion element 41 of the present invention, a protective member 42 for protecting the photoelectric conversion element 41, a heat dissipation member 43, and exterior finishes 44a and 44b.

[0112] The building material 40 of the present invention may include a heat dissipation member 43 having a higher thermal conductivity than that of the photoelectric conversion element 41. When the building material 40 is used for a roof or the like, the temperature of the photoelectric conversion element 41 may rise due to sunlight, and thus the photoelectric conversion efficiency may be reduced. By using the heat dissipation member 43, a reduction in the photoelectric conversion efficiency can be suppressed. Examples of the heat dissipation member 43 include metals, alloys, liquid metals, and liquid resins.

[0113] In addition, the building material 40 of the present invention may include exterior finishes 44a and 44b. The exterior finishes 44a and 44b may exhibit different colors or may exhibit the same color. The exterior finishes 44a and 44b may be composed of the same member or may be composed of different members. A coating or a transparent substrate may be used as each exterior finish. An exterior finish with low light absorption and high heat shielding properties is preferred.

[0114] Examples

[0115] The present invention will be described in more detail below by way of examples and comparative examples. Without departing from the gist of the present invention, the present invention is in no way limited to the following examples. In the description of the following examples, unless otherwise indicated, the term "parts" is based on mass.

[0116] <Manufacture of P-type semiconductor crystal particles 1>

[0117] Step (1)

[0118] Under a nitrogen gas flow atmosphere, 5.46 parts of phthalonitrile and 45 parts of α-chloronaphthalene were put into a reaction kettle. Then, the mixture was heated so that its temperature rose to 30 °C and then maintained at that temperature. Next, at this temperature (30 °C), 3.75 parts of gallium trichloride were put into the mixture. The moisture concentration of the mixture during charging was 150 ppm.

[0119] Then, the temperature of the mixture was raised to 200 °C. Next, under a nitrogen gas flow atmosphere, the mixture was reacted at a temperature of 200 °C for 4.5 hours and then cooled. The product was filtered when the temperature reached 150 °C. The obtained filtrate was dispersed and washed with N,N-dimethylformamide at a temperature of 140 °C for 2 hours and then filtered. The obtained filtrate was washed with methanol and then dried to obtain chloro-gallium phthalocyanine particles with a yield of 71%.

[0120] Step (2)

[0121] 4.65 parts of gallium chlorophthalocyanine particles were dissolved in 139.5 parts of concentrated sulfuric acid at 10°C. The solution was then added dropwise to 620 parts of ice water with stirring, causing the particles to precipitate again. The solution was then filtered under reduced pressure using a filter press. A filter No. 5C (manufactured by Advantec Toyo Kaisha, Ltd.) was used as the filter.

[0122] The resulting wet filter cake (filtrate) was dispersed and washed with 2% ammonia water for 30 minutes, and then filtered using a filter press. Next, the resulting wet filter cake (filtrate) was dispersed and washed with deionized water, and then filtered three times using a filter press.

[0123] Finally, the filtrate was freeze-dried to obtain hydroxy gallium phthalocyanine particles (hydrated hydroxy gallium phthalocyanine particles) with a solid content of 23% by mass in a yield of 71%. The hydroxy gallium phthalocyanine particles were dried using a hyper-dry dryer (trade name: HD-06R, frequency (oscillation frequency): 2,455 MHz ± 15 MHz, manufactured by Biocon (Japan) Ltd.). This yielded hydroxy gallium phthalocyanine (OHGaPc) particles (crystals) with a water content of less than 1.0% by mass.

[0124] Step (3)

[0125] Five parts of hydroxygallium phthalocyanine particles were mixed with five parts of N-methylformamide solvent, and the mixture was dispersed for 6 hours in a sand mill (TSG-1 / 4G-4U, manufactured by Igarashi Machine Production Co., Ltd. (now AIMEX Co., Ltd.), with a disc diameter of 70 mm and a number of discs of 5) containing five parts of glass beads. The mixture was then filtered and dried to obtain P-type semiconductor crystal particles 1 (specific gravity: 1.6).

[0126] <Preparation of Resin Solution 1>

[0127] 1.0 part of polyvinyl butyral resin (product name: S-LEC (trademark) BM-2, manufactured by Sekisui Chemical Co., Ltd., specific gravity: 1.6) was dissolved in 19 parts of 2-propanol by stirring for 24 hours to provide resin solution 1.

[0128] (Example 1)

[0129] [Formation of the electron transport layer]

[0130] A square glass substrate with ITO, 25 mm on each side, was washed. A solution obtained by diluting a tin(II) oxide colloidal dispersion with water to a volume ratio of 1 / 7 was then spin-coated onto the glass substrate at 5,000 rpm for 30 seconds. The resulting material was then heated at 150°C for 30 minutes and dried in a humidity environment with a dew point temperature of -20°C to form an electron transport layer.

[0131] [Formation of the photoelectric conversion layer]

[0132] Lead iodide (1.2 M), lead bromide (0.15 M), formamidinium hydroiodate (1.0 M), methylammonium bromide (0.15 M), and cesium iodide (0.13 M) were dissolved in a mixed solvent containing N,N-dimethylformamide and dimethyl sulfoxide in a volume ratio of 4:1 to prepare a photoelectric conversion layer coating solution. The coating solution was spin-coated onto the electron transport layer at 2,700 rpm for 10 seconds, followed by spin-coating at 5,000 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 form a Cs-based coating. 0.1 (MA 0.17 FA 0.83 ) 0.9 Pb(I 0.9 Br 0.1 )3 forms the photoelectric conversion layer.

[0133] [Formation of the charge transport layer]

[0134] 0.1 parts of P-type semiconductor crystal particles 1 and 0.01 parts of calixarene compound (see Japanese Patent Application Publication No. 2003-207913) were mixed with 10.6 parts of 2-propanol. 11 parts of beads (zirconia beads, Torayceram (trademark) zirconia beads, 0.3 mm) were added to the mixture, and then dispersed for 3 hours using a coating shaker (manufactured by Toyo Seiki Co., Ltd.). Afterwards, 0.2 parts of resin solution 1 were added, and the mixture was dispersed again using a coating shaker for 4 hours to prepare a charge transport layer solution. The charge transport layer solution was spin-coated onto a photoelectric conversion layer at 1,000 rpm for 30 seconds, and the resulting material was heated at 60°C for 10 minutes to form a charge transport layer with a thickness of approximately 150 nm.

[0135] [Introduction of the second charge transport layer]

[0136] 0.08 parts of Spiro-OMeTAD, serving as the material for the second charge transport layer, were dissolved in 1.13 parts of chlorobenzene. The 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(III)tris(bis(trifluoromethanesulfonyl)imide)]. The material solution was then spin-coated onto the charge transport layer at 2,000 rpm for 30 seconds to form the second charge transport layer.

[0137] [Formation of the first electrode]

[0138] Each layer, with a thickness of 70 nm and an area of ​​0.09 cm², was formed on the second charge transport layer using vacuum phase deposition. 2 Ten gold electrodes were used to obtain a photoelectric conversion element.

[0139] [Analysis of compound amount]

[0140] The electrode surfaces of the photoelectric conversion element are peeled off, exposing the surface of the charge transport layer. The surface of the charge transport layer is then wiped with a cotton swab soaked in solvent, and dissolved in deuterated sulfuric acid. 1 H-NMR determination (equipment: AVANCE III500, manufactured by BRUKER). Furthermore, the presence of compounds was determined by mass and structural analysis of the stripped charge transport layer components via GPC and MALDI-TOF-MS, IR, gas chromatography, and elemental analysis such as XPS or EDX.

[0141] In addition, after cutting the photoelectric conversion element and fixing the sample on the tilted sample stage, the thickness of the layer was determined using a cross-sectional SEM (equipment: SmartSEM, manufactured by Carl Zeiss Co., Ltd.).

[0142] (Example 2)

[0143] Except for changing the thickness of the charge transport layer to 200 nm, the photoelectric conversion element was obtained in the same manner as in Example 1.

[0144] (Example 3)

[0145] Except for changing the mass ratio of P-type semiconductor crystal particles 1 to resin to 3 times, the photoelectric conversion element was obtained in the same manner as in Example 1.

[0146] (Example 4)

[0147] Except for changing the mass ratio of P-type semiconductor crystal particles 1 to resin to 5 times, the photoelectric conversion element was obtained in the same manner as in Example 1.

[0148] (Example 5)

[0149] Except for changing the mass ratio of P-type semiconductor crystal particles 1 to resin to 30 times, the photoelectric conversion element was obtained in the same manner as in Example 1.

[0150] (Example 6)

[0151] Except for changing the mass ratio of P-type semiconductor crystal particles 1 to resin to 35 times, the photoelectric conversion element was obtained in the same manner as in Example 1.

[0152] (Example 7)

[0153] Except for changing the thickness of the charge transport layer to 89 nm, the photoelectric conversion element was obtained in the same manner as in Example 1.

[0154] (Example 8)

[0155] Except for changing the thickness of the charge transport layer to 300 nm, the photoelectric conversion element was obtained in the same manner as in Example 1.

[0156] (Example 9)

[0157] The photoelectric conversion element was obtained in the same manner as in Example 1, except that the P-type semiconductor crystal particle 1 was replaced with tetraphenylporphyrin (TPP). The tetraphenylporphyrin (TPP) used as the P-type semiconductor crystal particle 1 is crystalline.

[0158] (Example 10)

[0159] The photoelectric conversion element was obtained in the same manner as in Example 1, except that the P-type semiconductor crystal particle 1 was changed to 4,4',4'',4'''-(porphyrin-5,10,15,20-tetrayl)tetra(benzoic acid). The 4,4',4'',4'''-(porphyrin-5,10,15,20-tetrayl)tetra(benzoic acid) used as the P-type semiconductor crystal particle 1 was crystalline.

[0160] (Example 11)

[0161] The photoelectric conversion element was obtained in the same manner as in Example 1, except that the P-type semiconductor crystal particle 1 was replaced with 1-aminoanthraquinone-2-sulfonic acid. The 1-aminoanthraquinone-2-sulfonic acid used as the P-type semiconductor crystal particle 1 was crystalline.

[0162] (Example 12)

[0163] The photoelectric conversion element was obtained in the same manner as in Example 1, except that calixarene compounds were not used.

[0164] (Example 13)

[0165] The photoelectric conversion element is obtained in the same manner as in Example 1, except that a second charge transport layer is not provided.

[0166] (Example 14)

[0167] The photoelectric conversion element was obtained in the same manner as in Example 1, except that the resin was changed to poly(3-hexylthiophene-2,5-diyl) (P3HT).

[0168] (Example 15)

[0169] The photoelectric conversion element was obtained in the same manner as in Example 1, except that the P-type semiconductor crystal particle 1 was replaced with quinacridone particles. The quinacridone particles used as the P-type semiconductor crystal particle 1 were crystalline.

[0170] (Comparative Example 1)

[0171] In the manufacturing process of P-type semiconductor crystal particle 1, step (3) is omitted, and P-type semiconductor particle 2 that has not been converted into crystal is obtained. Except that P-type semiconductor particle 2 is used instead of P-type semiconductor crystal particle 1 in the formation of the charge transport layer, the photoelectric conversion element is obtained in the same manner as in Example 1. The P-type semiconductor particle 2 that has not been converted into crystal is amorphous.

[0172] (Comparative Example 2)

[0173] Except for replacing the P-type semiconductor crystal particles 1 with copper phthalocyanine particles, the photoelectric conversion element was obtained in the same manner as in Example 1.

[0174] (Comparative Example 3)

[0175] The photoelectric conversion element was obtained in the same manner as in Example 1, except that no resin was used.

[0176] (Comparative Example 4)

[0177] The photoelectric conversion element was obtained in the same manner as in Example 1, except that the P-type semiconductor crystal particle 1 was changed to Spiro-OMeTAD and the polyvinyl butyral was changed to polymethyl methacrylate (PMMA, manufactured by Sigma-Aldrich LLC).

[0178] [evaluate]

[0179] A power supply (model 236, manufactured by Keithley Instruments) was connected between the electrodes of the photoelectric conversion element manufactured in Example 1, and a power intensity of 110 mW / cm was used. 2 A solar simulator (manufactured by Yamashita Denso Corporation) was used to illuminate the elements with constant light; the resulting current and voltage were measured to determine their photoelectric conversion efficiency. Furthermore, measurements were taken individually for each of the 10 electrodes of each element, and the maximum measured value was used as the representative value for the element. The elements were then continuously illuminated with 10,000 Lx of light using a white LED, and their photoelectric conversion efficiency was measured after 60 days. The retention rate of the photoelectric conversion efficiency after 60 days relative to the initial photoelectric conversion efficiency was then evaluated as a durability assessment. These results, along with the initial photoelectric conversion efficiency, are shown in Table 2.

[0180] The initial photoelectric conversion efficiency and the maintenance rate of photoelectric conversion efficiency after 60 days of the photoelectric conversion elements of Examples 2-15 and Comparative Examples 1-4 were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0181] [Table 2]

[0182] Table 2

[0183]

[0184] This invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, the claims are appended to disclose the scope of the invention.

[0185] This application references Japanese patent applications filed on October 27, 2023: No. 2023-184761, No. 2023-184756, No. 2023-184750, No. 2023-216294, No. 2023-216296, No. 2023-216299, and No. 2024-022244, filed on February 16, 2024. The following patent applications, filed on February 16, 2024: 2024-022251, 2024-022246, 2024-077353, 2024-05, 2024, and 2024-186698, are hereby cited as priority, and the entire contents of these patent applications are incorporated herein by reference.

[0186] Explanation of reference numerals in the attached figures

[0187] 1 Photoelectric conversion element

[0188] 2 substrates

[0189] 3 Second electrode

[0190] 4 Electron transport layer

[0191] 5 Photoelectric conversion layer

[0192] 6 charge transport layer

[0193] 7 First Electrode

[0194] 8 Second charge transport layer

[0195] 30 moving bodies

[0196] 31, 41 Photoelectric conversion element

[0197] 32 fuselage

[0198] 40 Building Materials

[0199] 42 Protective components

[0200] 43 Heat dissipation components

[0201] 44a, 44b Exterior

Claims

1. A photoelectric conversion element, comprising: First electrode; The second electrode; and A photoelectric conversion layer is disposed between the first electrode and the second electrode, the photoelectric conversion layer containing crystals with a perovskite structure. The photoelectric conversion element includes a charge transport layer between the photoelectric conversion layer and the first electrode. The charge transport layer contains a P-type semiconductor crystal and a resin, and The P-type semiconductor crystal has at least one functional group selected from the group consisting of hydroxyl, carboxyl, amino, imino and sulfonyl groups.

2. A photoelectric conversion element, comprising: First electrode; The second electrode; and A photoelectric conversion layer is disposed between the first electrode and the second electrode, the photoelectric conversion layer containing crystals with a perovskite structure. The photoelectric conversion element includes a charge transport layer between the photoelectric conversion layer and the first electrode. The charge transport layer contains a P-type semiconductor crystal and a resin, and The P-type semiconductor crystal has functional groups that can act as hydrogen bond donors.

3. A photoelectric conversion element, comprising: First electrode; The second electrode; and A photoelectric conversion layer is disposed between the first electrode and the second electrode, the photoelectric conversion layer containing crystals with a perovskite structure. The photoelectric conversion element includes a charge transport layer between the photoelectric conversion layer and the first electrode. The charge transport layer contains a P-type semiconductor crystal and a resin, and The P-type semiconductor crystal has Lewis basic functional groups.

4. The photoelectric conversion element according to any one of claims 1 to 3, wherein the charge transport layer is in contact with the photoelectric conversion layer.

5. The photoelectric conversion element according to any one of claims 1 to 4, wherein the P-type semiconductor crystal is dispersed in the resin in the charge transport layer.

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

7. The photoelectric conversion element according to any one of claims 1 to 6, wherein the thickness of the charge transport layer is 10 nm or more and 400 nm or less.

8. The photoelectric conversion element according to any one of claims 1 to 6, wherein the thickness of the charge transport layer is 100 nm or more and 200 nm or less.

9. The photoelectric conversion element according to any one of claims 1 to 8, wherein the photoelectric conversion element includes a second charge transport layer between the first electrode and the charge transport layer.

10. The photoelectric conversion element according to any one of claims 1 to 9, wherein the resin is polyvinyl acetal resin.

11. The photoelectric conversion element according to any one of claims 1 to 10, wherein the P-type semiconductor crystal is a cyclic conjugated compound in which a plurality of pyrrole rings are bonded by conjugated bonds.

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

13. A mobile body comprising the 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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