Photoelectric conversion element, photoelectric conversion material, and method for producing photoelectric conversion element

Abstract

A photoelectric conversion element (100) according to the present disclosure comprises a first electrode (2), a photoelectric conversion layer (4), and a second electrode (6). The photoelectric conversion layer (4) includes a perovskite compound and at least one compound selected from the group consisting of triptycene and triptycene derivatives. A photoelectric conversion material according to the present disclosure includes a perovskite compound and at least one compound selected from the group consisting of triptycene and triptycene derivatives.

Description

Photoelectric conversion element, photoelectric conversion material, and method for manufacturing a photoelectric conversion element

[0001] This disclosure relates to a photoelectric conversion element, a photoelectric conversion material, and a method for manufacturing a photoelectric conversion element.

[0002] In recent years, perovskite solar cells have been researched and developed. In perovskite solar cells, perovskite compounds represented by the chemical formula ABX3 (where A is a monovalent cation, B is a divalent cation, and X is a halogen anion) are used as photoelectric conversion materials.

[0003] Various techniques have been proposed to improve the photoelectric conversion efficiency of perovskite solar cells. For example, Non-Patent Document 1 discloses a technique for forming a TBAPbI3 protective layer on the surface of a CsPbI3 layer by first depositing a layer made of CsPbI3 and then depositing a layer made of tetrabutylammonium iodide (TBAI) on top of that layer.

[0004] Xiamomin Liu, et al., Angewandte Chemie, 2021, Vol. 133, pp. 12459–12463.

[0005] This disclosure aims to provide a technology for improving the photoelectric conversion efficiency in a photoelectric conversion device that includes a perovskite compound as a photoelectric conversion material.

[0006] The photoelectric conversion element of the present disclosure comprises a first electrode, a photoelectric conversion layer, and a second electrode, wherein the photoelectric conversion layer comprises a perovskite compound and at least one compound selected from the group consisting of triptycene and triptycene derivatives.

[0007] This disclosure describes how to improve the photoelectric conversion efficiency in a photoelectric conversion device that includes a perovskite compound as a photoelectric conversion material.

[0008] Figure 1 is a cross-sectional view showing the schematic configuration of the photoelectric conversion element 100 of the first embodiment. Figure 2 is a graph showing the IV characteristics of the photoelectric conversion elements of Example 1, Example 2, and Reference Example 1. Figure 3 is a graph showing the IV characteristics of the photoelectric conversion elements of Example 3 and Example 4. Figure 4 is a graph showing the IV characteristics of the photoelectric conversion elements of Example 5, Example 6, and Reference Example 2.

[0009] Embodiments of the present disclosure will be described below with reference to the drawings.

[0010] (First Embodiment) The photoelectric conversion element according to the first embodiment comprises a first electrode, a photoelectric conversion layer, and a second electrode. The photoelectric conversion element according to the first embodiment may also comprise the first electrode, the photoelectric conversion layer, and the second electrode in this order. The photoelectric conversion layer comprises a perovskite compound and at least one compound selected from the group consisting of triptycene and triptycene derivatives.

[0011] The photoelectric conversion element according to the first embodiment can increase its open-circuit voltage by including a photoelectric conversion layer having the above configuration. As a result, the photoelectric conversion element according to the first embodiment can improve its photoelectric conversion efficiency.

[0012] In this specification, a triptycene derivative is, for example, a compound in which some of the hydrogen atoms of triptycene are replaced by halogen atoms. That is, a triptycene derivative may contain halogen atoms, or it may contain iodine.

[0013] A photoelectric conversion element is, for example, a solar cell.

[0014] Figure 1 is a cross-sectional view showing the schematic configuration of the photoelectric conversion element 100 of the first embodiment.

[0015] The photoelectric conversion element 100 comprises a substrate 1, a first electrode 2, an electron transport layer 3, a photoelectric conversion layer 4, a hole transport layer 5, and a second electrode 6, in this order. Note that the substrate 1, electron transport layer 3, and hole transport layer 5 are not required.

[0016] When light is shone on the photoelectric conversion element 100, the photoelectric conversion layer 4 absorbs the light and separates its charge into electrons and holes. The electrons generated by this charge separation move to the first electrode 2 through the electron transport layer 3. Meanwhile, the holes generated in the photoelectric conversion layer 4 move to the second electrode 6 via the hole transport layer 5. As a result, the photoelectric conversion element 100 can extract current from the first electrode 2, which acts as the negative electrode, and the second electrode 6, which acts as the positive electrode.

[0017] The following describes in detail each component of the photoelectric conversion element 100.

[0018] (Photoelectric conversion layer 4) As described above, the photoelectric conversion layer 4 includes a perovskite compound and at least one compound selected from the group consisting of triptycene and triptycene derivatives. For example, the photoelectric conversion layer 4 may be a single layer, and the single layer may include a perovskite compound and at least one compound selected from the group consisting of triptycene and triptycene derivatives.

[0019] Hereinafter, in this specification, "at least one compound selected from the group consisting of triptycenes and triptycene derivatives" will be referred to as "triptycene compounds."

[0020] In the photoelectric conversion layer 4, the triptycene compounds may be present between the crystals of the perovskite compound. It is believed that the presence of the triptycene compounds in the photoelectric conversion layer 4 in this state forms carrier paths between the crystals of the perovskite compound, thereby further suppressing carrier recombination. Therefore, with this configuration, the photoelectric conversion element 100 of the first embodiment can further improve its photoelectric conversion efficiency.

[0021] The photoelectric conversion layer 4 may be a mixture of a perovskite compound and a triptycene compound, or the perovskite compound and the triptycene compound may be uniformly mixed throughout. Therefore, the photoelectric conversion layer 4 formed from such a material may have a uniform composition in the thickness direction, and may also have a uniform composition throughout.

[0022] To improve the photoelectric conversion efficiency of the photoelectric conversion element 100, the molar ratio of the triptycene compound to the perovskite compound in the photoelectric conversion layer 4 may be 0.01 or more and 0.25 or less. Specifically, this molar ratio is the ratio of the total amount of substance of the triptycene compounds to the amount of substance of the perovskite compound ((total amount of substance of triptycene compounds) / (amount of substance of the perovskite compound)). If multiple types of perovskite compounds are included, the amount of substance of the perovskite compound is the sum of the amounts of substance of those multiple types of perovskite compounds.

[0023] To further improve the photoelectric conversion efficiency of the photoelectric conversion element 100, the molar ratio of the triptycene compound to the perovskite compound in the photoelectric conversion layer 4 may be 0.01 or more and 0.20 or less.

[0024] The molar ratio of the triptycene compound to the perovskite compound can be determined, for example, by mass spectrometry using X-ray photoelectron spectroscopy (XPS) on the photoelectric conversion layer 4.

[0025] To improve the photoelectric conversion efficiency of the photoelectric conversion element 100, the triptycene derivative may include, for example, triiodotriptycene (e.g., 2,6,14-triiodotriptycene).

[0026] Perovskite compounds have high light absorption coefficients in the wavelength range of the solar spectrum and high carrier mobility. Therefore, a photoelectric conversion element equipped with a photoelectric conversion layer containing a perovskite compound as a photoelectric conversion material has high photoelectric conversion efficiency.

[0027] Perovskite compounds may contain halogen anions; that is, perovskite compounds may be halides.

[0028] The perovskite compound may be composed of a monovalent cation, a divalent cation, and a halogen anion. Here, the divalent cation may include at least one selected from the group consisting of Sn cations, Pb cations, and Ge cations.

[0029] The above-mentioned divalent cation may include at least one selected from the group consisting of Sn cations and Pb cations.

[0030] The monovalent cation in the perovskite compound may also contain inorganic cations. For example, the monovalent cation in the perovskite compound may contain 50 mol% or more of inorganic cations.

[0031] Perovskite compounds are represented, for example, by the compositional formula ABX3, where A is a monovalent cation, B is a divalent metal cation, and X is a monovalent anion.

[0032] Examples of monovalent cation A are organic cations or alkali metal cations. As mentioned above, monovalent cation A may also contain inorganic cations, i.e., alkali metal cations. Monovalent cation A may contain 50 mol% or more of inorganic cations, i.e., alkali metal cations.

[0033] An example of an organic cation is the methylammonium cation (CH3NH3) + ), formamidinium cation (NH2CHNH2 + ) or guanidinium ion (C(NH2)3 + )

[0034] Examples of alkali metal cations are Cs cations or Rb cations.

[0035] B is a divalent metal cation. Examples of divalent cations B include Pb cations, Sn cations, or Ge cations.

[0036] X is a monovalent anion. Examples of anion X are halogen anions. Halogen anions are, for example, the anions of chlorine, bromine, or iodine.

[0037] Each site of cation A, cation B, and anion X may contain multiple types of ions.

[0038] The perovskite compound may be at least one selected from the group consisting of CsSnI3, CsGeI3, and CsPbI3. The perovskite compound may contain at least one selected from the group consisting of CsSnI3 and CsPbI3.

[0039] The perovskite compound may be a perovskite compound in which the monovalent cation contains a formamidinium cation (NH2CHNH2 + ), and the divalent cation contains a Pb cation.

[0040] The photoelectric conversion layer 4 may further contain SnF2. When the perovskite compound contains a Sn cation as a divalent cation, the inclusion of SnF2 can reduce Sn defects. Therefore, by further including SnF2 in the photoelectric conversion material of the first embodiment, the photoelectric conversion efficiency can be improved.

[0041] In order to increase the photoelectric conversion efficiency, the surface of the photoelectric conversion layer 4 may be surface-treated with a metal halide. Specifically, a configuration may be adopted in which a metal halide is present in a surface vicinity region 41 including the surface 4a on the second electrode 6 side of the photoelectric conversion layer 4. Thereby, the photoelectric conversion efficiency of the photoelectric conversion element is improved. Examples of the metal halide include ZnF2.

[0042] The average primary particle diameter of the perovskite compound is, for example, 2 μm or more. When the average primary particle diameter of the perovskite compound is 2 μm or more, carrier recombination is further reduced. As a result, the photoelectric conversion efficiency of the photoelectric conversion element 100 of the first embodiment is further improved. In the photoelectric conversion element 100 of the first embodiment, the average primary particle diameter of the perovskite compound contained in the photoelectric conversion layer 4 is obtained by measuring the primary particle diameter of the perovskite compound using a scanning electron microscope (SEM) image and calculating the average value from the measured values. Here, the measured primary particle diameter is the maximum diameter of the primary particle. For example, 50 particles are selected in order from the largest primary particle diameter among the particles in the SEM image. An average value is calculated using these 50 primary particle diameters, and the obtained value is taken as the average primary particle diameter. The average primary particle diameter of the perovskite compound may be 5 μm or more, or may be 10 μm or more. The average primary particle diameter of the perovskite compound is, for example, 100 μm or less.

[0043] In the photoelectric conversion element 100 of the first embodiment, the energy of the PL emission peak may be substantially the same as the energy of the PL emission peak of the perovskite compound contained in the photoelectric conversion layer 4 of the photoelectric conversion element 100. That is, the band gap of the photoelectric conversion material constituting the photoelectric conversion layer 4 may be substantially the same as the band gap of the perovskite compound contained in the photoelectric conversion material. In other words, the crystal structure of the photoelectric conversion material constituting the photoelectric conversion layer 4 does not change depending on the presence or absence of the triphenylene compound, and the crystal structure of the perovskite compound to which the triphenylene compound is not added can be maintained. Therefore, the photoelectric conversion element 100 of the first embodiment can further improve the photoelectric conversion efficiency without changing the light absorption characteristics (for example, the wavelength of the absorbed light). Here, when the energy of the PL emission peak is substantially the same, it means that the difference in the energy of the PL emission peak is within the range of 0 eV or more and 0.03 eV or less. Also, when the band gap is substantially the same, it means that the difference in the band gap is within the range of 0 eV or more and 0.03 eV or less.

[0044] The thickness of the photoelectric conversion layer 4 is, for example, 50 nm or more and 10 μm or less.

[0045] The photoelectric conversion layer 4 can be formed by solution coating, printing, or vapor deposition. Examples of coating methods include doctor blade coating, bar coating, spray coating, dip coating, inkjet coating, slit coating (i.e., die coating), or spin coating.

[0046] (Substrate 1) The substrate 1 plays the role of holding each layer of the photoelectric conversion element 100. The substrate 1 can be formed from a transparent material. For example, a glass substrate or a plastic substrate can be used as the substrate 1. The plastic substrate may be, for example, a plastic film.

[0047] If the second electrode 6 is translucent, the substrate 1 may be made of a material that is not translucent. Such materials can include metals, ceramics, or resin materials with low translucency.

[0048] If the first electrode 2 has sufficient strength, the first electrode 2 can hold each layer, so the substrate 1 does not need to be provided.

[0049] (First electrode 2) The first electrode 2 is conductive.

[0050] The first electrode 2 is light-transmitting. For example, it transmits light from the visible region to the near-infrared region.

[0051] The first electrode 2 is made of, for example, a transparent and conductive material. Examples of such materials are metal oxides or metal nitrides. Examples of such materials are: (i) titanium oxide doped with at least one selected from the group consisting of lithium, magnesium, niobium, and fluorine; (ii) gallium oxide doped with at least one selected from the group consisting of tin and silicon; (iii) gallium nitride doped with at least one selected from the group consisting of silicon and oxygen; (iv) tin oxide doped with at least one selected from the group consisting of antimony and fluorine; (v) zinc oxide doped with at least one selected from the group consisting of boron, aluminum, gallium, and indium; (vi) indium-tin composite oxide; or (vii) composites thereof.

[0052] The first electrode 2 may be formed with a light-transmitting pattern. Examples of light-transmitting patterns include linear, wavy, grid-like, or perforated metal-like patterns with a large number of fine through-holes arranged regularly or irregularly. When the first electrode 2 has such patterns, light can pass through areas where there is no electrode material. Therefore, by providing a light-transmitting pattern, an opaque material can be used. Examples of opaque electrode materials include platinum, gold, silver, copper, aluminum, rhodium, indium, titanium, iron, nickel, tin, zinc, or alloys containing any of these. Conductive carbon materials may also be used as opaque electrode materials.

[0053] The light transmittance of the first electrode 2 does not necessarily have to be achieved by the light transmission pattern described above. For example, the first electrode 2 may be formed of a thin film of metal with a thickness of about 10 nm. Such thin film metals include, for example, platinum, gold, silver, copper, aluminum, rhodium, indium, titanium, iron, nickel, tin, zinc, or alloys containing any of these. A conductive carbon material may be used instead of these metallic materials.

[0054] If the photoelectric conversion element 100 does not have an electron transport layer 3, the first electrode 2 has blocking properties for holes from the photoelectric conversion layer 4. In this case, the first electrode 2 does not make ohmic contact with the photoelectric conversion layer 4. Furthermore, blocking properties for holes from the photoelectric conversion layer 4 refer to the property of allowing only electrons generated in the photoelectric conversion layer 4 to pass through, while preventing holes from passing through. The Fermi energy of a material having such properties is higher than the energy at the top of the valence band of the photoelectric conversion layer 4. The Fermi energy of a material having such properties may also be higher than the Fermi energy of the photoelectric conversion layer 4. Aluminum is a specific example of such a material.

[0055] If the photoelectric conversion element 100 includes an electron transport layer 3, the first electrode 2 does not need to have blocking properties for holes from the photoelectric conversion layer 4. In this case, the first electrode 2 may be made of a material capable of forming ohmic contact with the photoelectric conversion layer 4. In this case, the first electrode 2 may or may not be in ohmic contact with the photoelectric conversion layer 4.

[0056] The light transmittance of the first electrode 2 may be, for example, 50% or more, or 80% or more. The wavelength of light that the first electrode 2 should transmit depends on the absorption wavelength of the photoelectric conversion layer 4.

[0057] The thickness of the first electrode 2 may be, for example, 1 nm or more and 1000 nm or less.

[0058] (Electron transport layer 3) The electron transport layer 3 contains an electron transport material. The electron transport material may be a semiconductor. The electron transport layer 3 may be formed from a semiconductor with a band gap of 3.0 eV or more. This allows visible light and infrared light to be transmitted to the photoelectric conversion layer 4.

[0059] An example of an electron transport material is an inorganic n-type semiconductor.

[0060] Examples of inorganic n-type semiconductors are metal oxides, metal nitrides, or perovskite oxides. Examples of metal oxides are oxides of Cd, Zn, In, Pb, Mo, W, Sb, Bi, Cu, Hg, Ti, Ag, Mn, Fe, V, Sn, Zr, Sr, Ga, Si, or Cr. Metal oxides are, for example, TiO2 or SnO2. Metal nitrides are, for example, GaN. Perovskite oxides are, for example, SrTiO3 or CaTiO3.

[0061] To effectively transmit ultraviolet light to the photoelectric conversion layer 4, the electron transport layer 3 may use a semiconductor with a band gap of 6.0 eV or greater. Examples of such semiconductors include alkali metal or alkaline earth metal halides such as lithium fluoride and calcium fluoride, alkali metal oxides such as magnesium oxide, or silicon dioxide. In this case, to ensure the electron transport properties of the electron transport layer 3, the electron transport layer 3 may have a thickness of, for example, 10 nm or less.

[0062] The electron transport layer 3 may include multiple layers made of different materials.

[0063] (Hole transport layer 5) The hole transport layer 5 contains a hole transport material. The hole transport material is a material that transports holes. The hole transport material is, for example, an organic semiconductor or an inorganic semiconductor.

[0064] Examples of organic semiconductors include triphenylamine, triallylamine, phenylbenzidine, phenylenevinylene, tetrathiafulvalene, vinylnaphthalene, vinylcarbazole, thiophene, aniline, pyrrole, carbazole, triptycene, fluorene, azulene, pyrene, pentacene, perylene, acridine, or phthalocyanine.

[0065] Typical examples of organic semiconductors used as hole transport materials include 2,2′,7,7′-tetrakis-(N,N-di-p-methoxyphenylamine)9,9′-spirobifluorene, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (hereinafter also referred to as "PTAA"), poly(3-hexylthiophene-2,5-diyl), poly(3,4-ethylenedioxythiophene), or copper phthalocyanine.

[0066] Inorganic semiconductors used as hole transport materials are p-type semiconductors. Examples of inorganic semiconductors include Cu₂O, CuGaO₂, CuSCN, CuI, and NiO. x MoO x This is a carbon material such as V2O5 or graphene oxide, where x satisfies x > 0.

[0067] The hole transport layer 5 may include multiple layers made of different materials. For example, the hole transport characteristics can be improved by stacking multiple layers such that the ionization potential of the hole transport layer 5 decreases sequentially with respect to the ionization potential of the photoelectric conversion layer 4.

[0068] The thickness of the hole transport layer 5 may be 1 nm or more and 1000 nm or less, or 10 nm or more and 50 nm or less. This allows for sufficient hole transport characteristics to be achieved. Therefore, the low resistance of the photoelectric conversion element 100 can be maintained, and high photoelectric conversion efficiency can be realized.

[0069] The hole transport layer 5 is formed, for example, by coating, printing, or vapor deposition. This is the same as for the photoelectric conversion layer 4. Examples of coating methods include doctor blade method, bar coating method, spray method, dip coating method, inkjet method, slit coating method (i.e., die coating method), or spin coating method. An example of a printing method is screen printing. If necessary, the hole transport layer 5 may be fabricated by mixing multiple materials and then pressurized or fired. If the material of the hole transport layer 5 is an organic low molecular weight or an inorganic semiconductor, it is also possible to fabricate the hole transport layer 5 by vacuum deposition.

[0070] The hole transport layer 5 may contain additives in addition to the hole transport material to enhance conductivity. Examples of additives include supporting electrolytes, solvents, or dopants. Supporting electrolytes and solvents have the effect of stabilizing holes in the hole transport layer 5. Dopants have the effect of increasing the number of holes in the hole transport layer 5.

[0071] Examples of supporting electrolytes are ammonium salts, alkaline earth metal salts, or transition metal salts. Examples of ammonium salts are tetrabutylammonium perchlorate, tetraethylammonium hexafluoride phosphate, imidazolium salts, or pyridinium salts. Examples of alkali metal salts are lithium perchlorate or potassium borotetrafluoride. Examples of alkaline earth metal salts are lithium bis(trifluoromethanesulfonyl)imide or bis(trifluoromethanesulfonyl)imide calcium(II). Examples of transition metal salts are bis(trifluoromethanesulfonyl)imide zinc(II) or tris[4-tert-butyl-2-(1H-pyrazole-1-yl)pyridine]cobalt(III)tris(trifluoromethanesulfonyl)imide.

[0072] An example of a dopant is a fluorine-containing aromatic boron compound. An example of a fluorine-containing aromatic boron compound is tris(pentafluorophenyl)borane.

[0073] The solvent contained in the hole transport layer 5 may have excellent ionic conductivity. This solvent may be an aqueous solvent or an organic solvent. To further stabilize the solute, the solvent contained in the hole transport layer 5 may be an organic solvent. Examples of organic solvents are heterocyclic compound solvents such as tert-butylpyridine, pyridine, and n-methylpyrrolidone.

[0074] Ionic liquids may be used as solvents. Ionic liquids may be used alone or in mixtures with other solvents. Ionic liquids are desirable because they have low volatility and high flame retardancy.

[0075] Examples of ionic liquids include imidazolium-based liquids such as 1-ethyl-3-methylimidazolium tetracyanoborate, pyridine-based liquids, alicyclic amine-based liquids, aliphatic amine-based liquids, or azonium amine-based liquids.

[0076] (Second electrode 6) The second electrode 6 is conductive.

[0077] If the photoelectric conversion element 100 does not have a hole transport layer 5, the second electrode 6 has blocking properties for electrons from the photoelectric conversion layer 4. In this case, the second electrode 6 does not make ohmic contact with the photoelectric conversion layer 4. Blocking properties for electrons from the photoelectric conversion layer 4 refer to the property of allowing only holes generated in the photoelectric conversion layer 4 to pass through, while preventing electrons from passing through. The Fermi energy of a material having such properties is lower than the energy of the lower end of the conduction band of the photoelectric conversion layer 4. The Fermi energy of a material having such properties may also be lower than the Fermi energy of the photoelectric conversion layer 4. Specific materials include platinum, gold, or carbon materials such as graphene.

[0078] If the photoelectric conversion element 100 includes a hole transport layer 5, the second electrode 6 does not need to block electrons from the photoelectric conversion layer 4. In this case, the second electrode 6 may be made of a material capable of forming ohmic contact with the photoelectric conversion layer 4. This allows the second electrode 6 to be formed to be translucent.

[0079] Of the first electrode 2 and the second electrode 6, the electrode on the side into which light is incident only needs to be light-transmitting. Therefore, one of the first electrode 2 and the second electrode 6 does not need to be light-transmitting. In other words, one of the first electrode 2 and the second electrode 6 does not need to be made of a light-transmitting material, nor does it need to have a pattern that includes an opening that transmits light.

[0080] (Porous layer) The porous layer is formed on the electron transport layer 3, for example, by a coating method. If the photoelectric conversion element 100 does not have an electron transport layer 3, the porous layer is formed on the first electrode 2.

[0081] The porous structure introduced by the porous layer serves as the foundation for forming the photoelectric conversion layer 4. The porous layer does not hinder the light absorption of the photoelectric conversion layer 4 or the electron transfer from the photoelectric conversion layer 4 to the electron transport layer 3.

[0082] The porous layer includes a porous material.

[0083] Porous materials are formed, for example, by a series of insulating or semiconductor particles. Examples of insulating particles are aluminum oxide particles or silicon oxide particles. Examples of semiconductor particles are inorganic semiconductor particles. Examples of inorganic semiconductors are metal oxides, perovskite oxides of metallic elements, sulfides of metallic elements, or metal chalcogenides. Examples of metal oxides are oxides of Cd, Zn, In, Pb, Mo, W, Sb, Bi, Cu, Hg, Ti, Ag, Mn, Fe, V, Sn, Zr, Sr, Ga, Si, or Cr. An example of a metal oxide is TiO2. An example of a perovskite oxide of a metallic element is SrTiO3 or CaTiO3. Examples of metal element sulfides include CdS, ZnS, In2S3, PbS, Mo2S, WS2, Sb2S3, Bi2S3, ZnCdS2, or Cu2S. Examples of metal chalcogenides include CsSe, In2Se3, WSe2, HgS, PbSe, or CdTe.

[0084] The thickness of the porous layer may be 0.01 μm or more and 10 μm or less, or 0.05 μm or more and 1 μm or less.

[0085] The surface roughness of the porous layer may be 10 or greater, or 100 or greater, given by the effective area / projected area. The projected area is the area of ​​the shadow cast behind an object when it is illuminated directly from the front. The effective area is the actual surface area of ​​the object. The effective area can be calculated from the volume obtained from the projected area and thickness of the object, and from the specific surface area and bulk density of the materials constituting the object. The specific surface area is measured, for example, by the nitrogen adsorption method.

[0086] The voids within the porous layer are connected from one main surface of the porous layer to the other main surface. That is, the voids within the porous layer are connected from the main surface of the porous layer in contact with the photoelectric conversion layer 4 to the main surface of the porous layer in contact with the electron transport layer 3. As a result, the material of the photoelectric conversion layer 4 can fill the voids in the porous layer and reach the surface of the electron transport layer 3. Therefore, since the photoelectric conversion layer 4 and the electron transport layer 3 are in direct contact, electron transfer is possible.

[0087] By providing a porous layer, the photoelectric conversion layer 4 can be easily formed. The porous layer allows the material of the photoelectric conversion layer 4 to penetrate the voids within it, and the porous layer acts as a scaffold for the photoelectric conversion layer 4. Therefore, the material of the photoelectric conversion layer 4 is less likely to be repelled or aggregated on the surface of the porous layer. Consequently, the photoelectric conversion layer 4 can be easily formed as a uniform film. The photoelectric conversion layer 4 can be formed by the coating method described above.

[0088] The porous layer is expected to cause light scattering, which increases the optical path length of light passing through the photoelectric conversion layer 4. An increase in optical path length is predicted to increase the amount of electrons and holes generated in the photoelectric conversion layer 4.

[0089] (Method for manufacturing a photoelectric conversion element) The photoelectric conversion element of the first embodiment can be manufactured, for example, by the manufacturing method of the first embodiment described below.

[0090] The manufacturing method of the first embodiment includes the steps of forming a first electrode, forming a photoelectric conversion layer, and forming a second electrode, wherein the step of forming the photoelectric conversion layer includes preparing a mixed solution by mixing a precursor solution of a perovskite compound with a solution in which at least one compound selected from the group consisting of triptycene and triptycene derivatives is dissolved, and forming a coating film using the mixed solution.

[0091] According to the above manufacturing method, it is possible to provide a photoelectric conversion element with improved photoelectric conversion efficiency.

[0092] The manufacturing method of the first embodiment may further include firing the formed coating film.

[0093] The mixed solution prepared in the process of forming the photoelectric conversion layer is a precursor solution of the material constituting the photoelectric conversion layer. In other words, in the process of forming the photoelectric conversion layer, a precursor solution of the material constituting the photoelectric conversion layer is prepared, and the photoelectric conversion layer is formed by a coating film formed with that precursor solution.

[0094] In the process of forming a photoelectric conversion layer, the preparation of the mixed solution includes, for example, preparing a first solution, a second solution, and a third solution, and mixing the second solution and the third solution with the first solution.

[0095] Here, the first solution comprises a compound containing a monovalent cation and a halogen anion, a compound containing a divalent cation and a halogen anion, and a solvent. The second solution comprises a compound containing a divalent cation and at least one anion selected from the group consisting of F anion and Cl anion, and a solvent. The third solution comprises at least one compound selected from the group consisting of triptycene and triptycene derivatives, and a solvent.

[0096] According to the above manufacturing method, it is possible to provide a photoelectric conversion element with improved photoelectric conversion efficiency.

[0097] In the process of forming the photoelectric conversion layer, one type of solvent may be used as the solvent, or a mixed solvent containing multiple solvents may be used. The solvent may be, for example, a mixed solvent containing DMF (dimethylformamide) and DMSO (dimethyl sulfoxide).

[0098] In the process of forming the photoelectric conversion layer, for example, the prepared mixed solution is applied to the substrate by a coating method such as spin coating, and the resulting coating film is fired. Before firing, the coating film may be left to stand for a predetermined time to allow crystal nuclei to grow in the coating film. The firing temperature may be, for example, 50°C or higher and 250°C or lower. As an example, when a mixed solvent of DMF and DMSO (for example, a volume ratio of DMF:DMSO = 1:4) is used, for example, after growing crystal nuclei in the coating film at room temperature, the coating film may be fired at a temperature of about 50°C or higher and 180°C or lower. The substrate refers to the structure that serves as the base when forming the photoelectric conversion layer, and for example, the structure adjacent to the photoelectric conversion layer in a photoelectric conversion element. When the photoelectric conversion layer is placed on the first electrode in contact with the first electrode, the substrate is the first electrode. When the photoelectric conversion layer is placed in contact with an electron transport layer formed on the first electrode, the substrate is a laminate of the first electrode and the electron transport layer.

[0099] The manufacturing method of the first embodiment may further include steps such as forming an electron transport layer and forming a hole transport layer, depending on the configuration of the photoelectric conversion element to be manufactured.

[0100] (Second Embodiment) The photoelectric conversion material of the second embodiment will be described below. Matters described in the first embodiment may be omitted as appropriate.

[0101] The photoelectric conversion material of the second embodiment comprises a perovskite compound and at least one compound selected from the group consisting of triptycene and triptycene derivatives.

[0102] With the above configuration, the photoelectric conversion material of the second embodiment can improve the photoelectric conversion efficiency.

[0103] The above perovskite compound may be composed of a monovalent cation, a divalent cation, and a halogen anion. The divalent cation may include at least one selected from the group consisting of Sn cations, Pb cations, and Ge cations.

[0104] The photoelectric conversion material of the second embodiment can be used, for example, as the material for the photoelectric conversion layer of the photoelectric conversion element of the first embodiment. Therefore, the description of the material for the photoelectric conversion layer in the first embodiment also applies to the photoelectric conversion material of the first embodiment.

[0105] The photoelectric conversion material of the second embodiment can be manufactured, for example, by the following method.

[0106] First, a precursor solution of the photoelectric conversion material according to the second embodiment is prepared. The precursor solution of the photoelectric conversion material according to the second embodiment can be prepared, for example, by mixing a precursor solution of a perovskite compound with a solution in which at least one compound selected from the group consisting of triptycene and triptycene derivatives is dissolved. The raw materials used to prepare the precursor solution of the photoelectric conversion material according to the second embodiment are, for example, compounds containing a monovalent cation and a halogen anion such as CsI, compounds containing a divalent cation and a halogen anion such as SnI2, and compounds containing a divalent cation and an F anion such as SnF2. As a solvent, one solvent may be used, or a mixed solvent containing multiple solvents may be used. The solvent may be, for example, a mixed solvent containing DMF and DMSO.

[0107] The precursor solution for the photoelectric conversion material in the second embodiment may be prepared, for example, by first preparing a first solution containing a compound comprising a monovalent cation and a halogen anion, a compound comprising a divalent cation and a halogen anion, and a solvent; a second solution containing a compound comprising a divalent halogen and an F anion, and a solvent; and a third solution containing an ammonium salt and a solvent, and then mixing the second and third solutions with the first solution.

[0108] [Other Embodiments] (Note) The above description of embodiments discloses the following technologies.

[0109] (Technical 1) A photoelectric element comprising a first electrode, a photoelectric conversion layer, and a second electrode, wherein the photoelectric conversion layer comprises a perovskite compound and at least one compound selected from the group consisting of triptycene and triptycene derivatives.

[0110] This configuration allows the photoelectric conversion element of Technology 1 to improve its photoelectric conversion efficiency.

[0111] (Technical 2) The photoelectric conversion element according to Technical 1, wherein at least one compound selected from the group consisting of triptycene and triptycene derivatives is present between the crystals of the perovskite compound.

[0112] This configuration allows the photoelectric conversion element in Technology 2 to further improve its photoelectric conversion efficiency.

[0113] (Technical 3) The photoelectric conversion element according to Technical 1 or 2, wherein in the photoelectric conversion layer, the molar ratio of the total of the triptycene and the triptycene derivative to the perovskite compound is 0.01 or more and 0.25 or less.

[0114] This configuration allows the photoelectric conversion element in Technology 3 to further improve its photoelectric conversion efficiency.

[0115] (Technical 4) The triptycene derivative contains a halogen atom, and is a photoelectric conversion element according to any one of Technical 1 to 3.

[0116] This configuration allows the photoelectric conversion element in Technology 4 to further improve its photoelectric conversion efficiency.

[0117] (Technical 5) The triptycene derivative contains iodine, and the photoelectric conversion element is as described in any one of Technical 1 to 4.

[0118] This configuration allows the photoelectric conversion element in Technology 5 to further improve its photoelectric conversion efficiency.

[0119] (Technical 6) The triptycene derivative comprises triiodotriptycene, and is a photoelectric conversion element according to any one of Technical 1 to 5.

[0120] This configuration allows the photoelectric conversion element in technology 6 to further improve its photoelectric conversion efficiency.

[0121] (Technical 7) The photoelectric conversion element according to any one of Technical 1 to 6, wherein the perovskite compound is composed of a monovalent cation, a divalent cation, and a halogen anion, and the divalent cation comprises at least one selected from the group consisting of Sn cation, Pb cation, and Ge cation.

[0122] This configuration allows the photoelectric conversion element in Technology 7 to further improve its photoelectric conversion efficiency.

[0123] (Technical 8) The photoelectric conversion element according to Technical 7, wherein the monovalent cation includes an inorganic cation.

[0124] This configuration allows the photoelectric conversion element in Technology 8 to further improve its photoelectric conversion efficiency.

[0125] (Technical 9) The photoelectric conversion element according to Technical 7 or 8, wherein the divalent cation comprises at least one selected from the group consisting of Sn cations and Pb cations.

[0126] This configuration allows the photoelectric conversion element in technology 9 to further improve its photoelectric conversion efficiency.

[0127] (Technical 10) The photoelectric conversion element according to any one of Technical 7 to 9, wherein the perovskite compound comprises at least one selected from the group consisting of CsSnI3 and CsPbI3.

[0128] This configuration allows the photoelectric conversion element of technology 10 to further improve its photoelectric conversion efficiency.

[0129] (Technical 11) A photoelectric conversion element according to any one of Technical 7 to 10, wherein the monovalent cation comprises a formamidinium cation and the divalent cation comprises a Pb cation.

[0130] This configuration allows the photoelectric conversion element of technology 11 to further improve its photoelectric conversion efficiency.

[0131] (Technical 12) The photoelectric conversion element according to any one of Technical 1 to 11, wherein the photoelectric conversion layer further comprises SnF2.

[0132] This configuration allows the photoelectric conversion element of technology 12 to further improve its photoelectric conversion efficiency.

[0133] (Technical 13) A photoelectric conversion material comprising a perovskite compound and at least one compound selected from the group consisting of triptycene and triptycene derivatives.

[0134] With this configuration, the photoelectric conversion material of technology 13 can improve the photoelectric conversion efficiency of the photoelectric conversion material.

[0135] (Technical 14) The photoelectric conversion material according to Technical 13, wherein the perovskite compound is composed of a monovalent cation, a divalent cation, and a halogen anion, and the divalent cation comprises at least one selected from the group consisting of Sn cation, Pb cation, and Ge cation.

[0136] This configuration allows the photoelectric conversion material of technology 14 to further improve the photoelectric conversion efficiency of the photoelectric conversion material.

[0137] (Technical 15) A method for manufacturing a photoelectric element, comprising the steps of: forming a first electrode; forming a photoelectric conversion layer; and forming a second electrode, wherein the step of forming the photoelectric conversion layer comprises: preparing a mixed solution by mixing a precursor solution of a perovskite compound with a solution in which at least one compound selected from the group consisting of triptycene and triptycene derivatives is dissolved; and forming a coating film using the mixed solution.

[0138] This method allows the manufacturing method of technology 15 to produce a photoelectric conversion element with improved photoelectric conversion efficiency.

[0139] (Technical 16) A method for manufacturing a photoelectric element according to Technical 15, wherein the step of forming the photoelectric conversion layer comprises: preparing a first solution, a second solution, and a third solution; and mixing the second solution and the third solution with the first solution, the first solution comprising a compound comprising a monovalent cation and a halogen anion, a compound comprising a divalent cation and a halogen anion, and a solvent; the second solution comprising a compound comprising a divalent cation and at least one anion selected from the group consisting of F anion and Cl anion, and a solvent; and the third solution comprising at least one of the compounds selected from the group consisting of triptycene and the triptycene derivatives, and a solvent.

[0140] This method allows the manufacturing method of technology 16 to produce a photoelectric conversion element with improved photoelectric conversion efficiency.

[0141] (Technical 17) A method for manufacturing a photoelectric conversion element according to Technical 15 or 16, further comprising firing the formed coating film.

[0142] This method allows the manufacturing method of technology 17 to produce a photoelectric conversion element with improved photoelectric conversion efficiency.

[0143] The present disclosure will be described in more detail below with reference to examples and reference examples.

[0144] The preparation of the raw material solutions for the photoelectric conversion layer and hole transport layer, and the deposition of the films, were carried out in a glove box with oxygen and moisture concentrations of 1 ppm or less.

[0145] <Fabrication of Photoelectric Conversion Element> (Example 1) First, a glass substrate was prepared. This substrate serves as a support material in the photoelectric conversion element of this disclosure.

[0146] A layer of ITO (Indium Tin Oxide) was formed on the substrate by sputtering. Furthermore, a layer of ATO (Antimony Tin Oxide) was formed on top of the ITO layer by sputtering. In this way, the first electrode was formed.

[0147] Next, a dense layer of titanium oxide (TiO2) was formed on the ATO layer of the first electrode by the sol-gel method. In the sol-gel method, a solution mixed in the volume ratio of titanium(IV) isopropoxide:ethanol:hydrochloric acid = 0.1:1:0.001 was applied by spin coating, and then fired at 500°C for 30 minutes. The spin coating was performed at 4000 rpm for 10 seconds. This dense layer of titanium oxide (TiO2) corresponds, for example, to the electron transport layer described in the first embodiment above.

[0148] Next, 0.45 g of titanium dioxide paste 30NR-D (manufactured by Gratcell Solar Materials Pty Ltd) was dissolved in 2 mL of butanol solution. The resulting solution was applied to the electron transport layer by spin coating and then fired at 500°C for 30 minutes. In this way, a porous layer of titanium dioxide was formed. Spin coating was performed at 4000 rpm for 10 seconds. Both the dense layer of titanium dioxide and the porous layer of titanium dioxide possess electron transport properties. Therefore, it is possible to consider that the electron transport layer is composed of the dense layer of titanium dioxide and the porous layer of titanium dioxide.

[0149] The precursor solution for the photoelectric conversion layer was applied to the porous layer by spin coating, and then left to stand at room temperature for 10 minutes. Afterward, the coated film was baked at 50°C for 3 minutes, followed by 70°C for 10 minutes, and finally 160°C for 10 minutes. In this way, the photoelectric conversion layer was formed. Chlorobenzene, a poor solvent, was added dropwise during the spin coating process at 5000 rpm for 40 seconds.

[0150] The precursor solution for the photoelectric conversion layer was obtained as follows. First, a first solution with concentrations of 1.5 mol / L of SnI2 and CsI was prepared by adding SnI2 and CsI to a mixed solvent of DMF and DMSO (in a volume ratio of 2:8). Next, a second solution with a concentration of 1.5 mol / L of SnF2 was prepared by adding SnF2 to DMSO. Furthermore, a third solution with a concentration of 1.5 mol / L of triptycene was prepared by adding triptycene to DMF. The amount of Zn powder added was weighed to be 10 mol% relative to the first solution, and the first, second, and third solutions were added thereto to obtain the precursor solution. In the precursor solution of Example 1, the second solution was added at a concentration of 15 mol% and the third solution at a concentration of 2 mol% relative to the first solution.

[0151] As described above, in Example 1, a photoelectric conversion layer was obtained by firing a coating film formed using a precursor solution under the above conditions. The obtained photoelectric conversion layer was formed from a photoelectric conversion material containing 10 mol of Zn, 15 mol of SnF2, and 2 mol of triptycene per 100 mol of CsSnI3. That is, the molar ratio of the triptycene compound to the perovskite compound in the photoelectric conversion layer was 0.02. The ratio of each component in the photoelectric conversion material of Example 1 was determined from the charge ratio.

[0152] Next, the raw material solution for the hole transport layer was applied onto the photoelectric conversion layer by spin coating. In this way, the hole transport layer was formed. The raw material solution for the hole transport layer was prepared by dissolving 18 mg of PTAA (poly[bis(4-phenyl)(2,4,6-triphenyl)amine]) in 1 mL of chlorobenzene, and then adding 32 mol% of Li-TFSI [bis(trifluoromethanesulfonyl)imide lithium] relative to the PTAA and 154 mol% of tBP (4-tert-butylpyridine). Spin coating was performed at 4000 rpm for 20 seconds.

[0153] Next, a gold film was formed on the hole transport layer by vapor deposition. In this way, a second electrode with a thickness of 100 nm was formed.

[0154] Finally, UV-curing epoxy resin was applied around the substrate, bonded to another glass substrate, and then UV-cured. In this way, the epoxy resin was cured and the power generation element was sealed.

[0155] (Example 2) The surface of the formed photoelectric conversion layer was surface-treated using a ZnF2 solution. Specifically, ZnF2 was added to IPA (isopropyl alcohol) to prepare a 0.02 M (i.e., 0.02 mol / L) ZnF2 solution, which was applied to the surface of the photoelectric conversion layer and fired at 100°C for 10 minutes. Except for these changes, the photoelectric conversion element of Example 2 was fabricated in the same manner as in Example 1.

[0156] (Example 3) The precursor solution prepared for the fabrication of the photoelectric conversion layer was obtained as follows. First, the first and second solutions were prepared in the same manner as in Example 1. Furthermore, by adding 2,6,14-triiodotriptycene to DMF, a third solution with a concentration of 2,6,14-triiodotriptycene of 1.5 mol / L was prepared. The amount of Zn powder to be added was weighed to be 20 mol% relative to the first solution, and the first, second, and third solutions were added thereto to obtain the precursor solution. In the precursor solution of Example 3, the second solution was added to the first solution at a concentration of 20 mol%, and the third solution was added at a concentration of 14 mol%.

[0157] In Example 3, a photoelectric conversion layer was obtained by firing a coating film formed using a precursor solution in the same manner as in Example 1 at 50°C for 3 minutes, followed by firing at 70°C for 10 minutes, and finally at 220°C. The obtained photoelectric conversion layer was formed from a photoelectric conversion material containing 20 mol of Zn, 20 mol of SnF2, and 14 mol of 2,6,14-triiodotriptycene per 100 mol of CsSnI3. That is, the molar ratio of the triptycene compounds to the perovskite compound in the photoelectric conversion layer was 0.14. The ratio of each component in the photoelectric conversion material of Example 3 was determined from the charge ratio.

[0158] The photoelectric conversion layer for Example 3 was fabricated using the same method as in Example 1.

[0159] (Example 4) For comparison with Example 3, when preparing the precursor solution for the photoelectric conversion layer, the third solution in Example 3 was changed from 2,6,14-triiodotriptycene to triptycene, and the addition ratio of the second and third solutions to the first solution was adjusted in the same way as in Example 3. That is, the first and second solutions were prepared in the same way as in Example 1, and by further adding triptycene to DMF, a third solution with a triptycene concentration of 1.5 mol / L was prepared. Then, the amount of Zn powder to be added was weighed to be 20 mol% relative to the first solution, and the first, second, and third solutions were added thereto to obtain the precursor solution. In the precursor solution of Example 4, the second solution was added at a concentration of 20 mol% and the third solution at a concentration of 14 mol% relative to the first solution.

[0160] The photoelectric conversion layer for Example 4 was fabricated using the same method as in Example 1.

[0161] (Reference Example 1) In preparing the photoelectric conversion layer, the amount of Zn powder added was weighed to be 10 mol% relative to the first solution, and the precursor solution for the photoelectric conversion layer was prepared by adding only the second solution to the first solution without adding the third solution. In other words, the photoelectric conversion layer in Reference Example 1 did not contain triptycene compounds.

[0162] (Examples 5, 6, and 2) A layer of FTO (Fluorine-doped tin oxide) was formed on the substrate by sputtering. The first electrode was formed in this manner. The same glass substrate as in Example 1 was used.

[0163] Next, a tin oxide dispersion was spin-coated onto the first electrode and fired at 150°C for 30 minutes to form an electron transport layer.

[0164] The precursor solution for the photoelectric conversion layer was obtained as follows. First, PbI2, FAI (formamidinium iodide), CsI, and RbI were added to a mixed solvent of DMF and DMSO to prepare the solution. Triptycene was added to the resulting solution so that the amount of triptycene relative to the perovskite compound to be formed was 0.1 mol% in Example 5 and 1 mol% in Example 6. In Reference Example 2, no triptycene was added. In this way, the precursor solutions for Example 5, Example 6, and Reference Example 2 were prepared.

[0165] The precursor solution prepared as described above was spin-coated onto the electron transport layer and fired at 150°C for 30 minutes to form the photoelectric conversion layer. Spin-coating was performed while adding toluene, a poor solvent, dropwise.

[0166] Next, the raw material solution for the hole transport layer was applied onto the photoelectric conversion layer by spin coating. The raw material solution for the hole transport layer was prepared by dissolving PTAA (poly[bis(4-phenyl)(2,4,6-triphenyl)amine]), Li-TFSI [bis(trifluoromethanesulfonyl)imide lithium], and tBP (4-tert-butylpyridine) in toluene. After applying this raw material solution onto the photoelectric conversion layer by spin coating, the hole transport layer was formed by firing at 80°C for 1 minute.

[0167] Next, a MoO3 layer was deposited on the hole transport layer, followed by sputter deposition of ITO (indium tin oxide), and finally Au was deposited to form the second electrode.

[0168] Finally, UV-curing epoxy resin was applied around the substrate, bonded to another glass substrate, and then UV-cured. In this way, the epoxy resin was cured and the power generation element was sealed.

[0169] <Evaluation of Photoelectric Conversion Elements> The current-voltage characteristics (i.e., IV characteristics) of the photoelectric conversion elements in the examples and reference examples were evaluated.

[0170] For the evaluation of characteristics, a solar simulator (manufactured by Spectral Instruments Co., Ltd.) and an electrochemical analyzer ALS (manufactured by BAS Inc.) were used. The photoelectric conversion element was irradiated under simulated sunlight of 1 sun. The output of the solar simulator was set to 100 mW / cm 2 . By measuring the output current value while changing the applied voltage using the electrochemical analyzer, the IV characteristics of the photoelectric conversion element were measured.

[0171] The measurement results are shown in Table 1 and Table 2. PCE represents the conversion efficiency. J SC represents the short-circuit current density. V oc represents the open-circuit voltage. FF represents the fill factor. Also, Table 1 shows the additive (i.e., triphenylene compounds) to CsSnI3, which is a perovskite compound constituting the photoelectric conversion layer, the firing temperature for forming the photoelectric conversion layer, and the presence or absence of surface treatment (i.e., treatment with ZnF2 solution) for the photoelectric conversion layer. Here, it has been confirmed by preliminary experiments by the applicant that there is no significant difference between the molar ratio of the triphenylene compounds to the perovskite compound determined from the elemental analysis of the fabricated photoelectric conversion layer and the molar ratio of the triphenylene compounds to the perovskite compound obtained using the charging ratio of the raw materials. That is, for example, in Example 1, since the amount of triphenylene added as a triphenylene compound was 2 mol with respect to 100 mol of the perovskite compound, the molar ratio of the triphenylene compounds to the perovskite compound in the fabricated photoelectric conversion layer can be regarded as 0.02. The same applies to other examples and reference examples.

[0172] Figure 2 is a graph showing the IV characteristics of the photoelectric conversion elements of Example 1, Example 2, and Reference Example 1. Figure 3 is a graph showing the IV characteristics of the photoelectric conversion elements of Example 3 and Example 4.

[0173]

[0174] As shown in Table 1, the photoelectric conversion elements of Examples 1 to 4, which were equipped with a photoelectric conversion layer containing a triptycene compound, had a higher conversion efficiency than the photoelectric conversion element of Reference Example 1, which was not equipped with a triptycene compound in its photoelectric conversion layer.

[0175] As described above, the results of Example 3 confirmed that when 2,6,14-triiodotriptycene, a triptycene derivative, is added as a triptycene compound, the photoelectric conversion efficiency is improved, similar to when triptycene is added.

[0176] Table 2 shows, for Examples 5, 6, and Reference Example 2, whether or not triptycene was added to the lead perovskite compound constituting the photoelectric conversion layer, the molar ratio of the triptycene compound to the perovskite compound, and the characteristics of the photoelectric conversion element.

[0177] Figure 4 is a graph showing the IV characteristics of the photoelectric conversion elements of Example 5, Example 6, and Reference Example 2. In other words, Figure 4 allows for a comparison of the IV characteristics of photoelectric conversion elements with different amounts of triptycene added.

[0178]

[0179] As shown in Table 2, the photoelectric conversion elements of Examples 5 and 6, which were equipped with a photoelectric conversion layer containing triptycene, had a higher conversion efficiency than Reference Example 2, which was equipped with a photoelectric conversion layer that did not contain triptycene.

[0180] The photoelectric conversion material disclosed herein can be used, for example, in a solar cell.

Claims

1. A photoelectric element comprising a first electrode, a photoelectric conversion layer, and a second electrode, wherein the photoelectric conversion layer comprises a perovskite compound and at least one compound selected from the group consisting of triptycene and triptycene derivatives.

2. The photoelectric element according to claim 1, wherein at least one compound selected from the group consisting of triptycene and triptycene derivatives is present between the crystals of the perovskite compound.

3. The photoelectric conversion element according to claim 1, wherein in the photoelectric conversion layer, the molar ratio of the total of the triptycene and the triptycene derivative to the perovskite compound is 0.01 or more and 0.25 or less.

4. The photoelectric conversion element according to claim 1, wherein the triptycene derivative contains a halogen atom.

5. The photoelectric conversion element according to claim 1, wherein the triptycene derivative contains iodine.

6. The photoelectric conversion element according to claim 1, wherein the triptycene derivative includes triiodotriptycene.

7. The photoelectric element according to claim 1, wherein the perovskite compound is composed of a monovalent cation, a divalent cation, and a halogen anion, and the divalent cation comprises at least one selected from the group consisting of Sn cation, Pb cation, and Ge cation.

8. The photoelectric conversion element according to claim 7, wherein the monovalent cation includes an inorganic cation.

9. The photoelectric conversion element according to claim 7, wherein the divalent cation comprises at least one selected from the group consisting of Sn cations and Pb cations.

10. The photoelectric conversion element according to claim 7, wherein the perovskite compound comprises at least one selected from the group consisting of CsSnI3 and CsPbI3.

11. The photoelectric element according to claim 7, wherein the monovalent cation comprises a formamidinium cation and the divalent cation comprises a Pb cation.

12. The photoelectric conversion element according to claim 1, wherein the photoelectric conversion layer further comprises SnF2.

13. A photoelectric conversion material comprising a perovskite compound and at least one compound selected from the group consisting of triptycene and triptycene derivatives.

14. The photoelectric conversion material according to claim 13, wherein the perovskite compound is composed of a monovalent cation, a divalent cation, and a halogen anion, and the divalent cation comprises at least one selected from the group consisting of Sn cation, Pb cation, and Ge cation.

15. A method for manufacturing a photoelectric element, comprising the steps of: forming a first electrode; forming a photoelectric conversion layer; and forming a second electrode, wherein the step of forming the photoelectric conversion layer comprises: preparing a mixed solution by mixing a precursor solution of a perovskite compound with a solution in which at least one compound selected from the group consisting of triptycene and triptycene derivatives is dissolved; and forming a coating film using the mixed solution.

16. A method for manufacturing a photoelectric element according to claim 15, wherein the step of forming the photoelectric conversion layer comprises: preparing a first solution, a second solution, and a third solution; and mixing the second solution and the third solution with the first solution, the first solution comprising a compound comprising a monovalent cation and a halogen anion, a compound comprising a divalent cation and a halogen anion, and a solvent; the second solution comprising a compound comprising a divalent cation and at least one anion selected from the group consisting of F anion and Cl anion, and a solvent; and the third solution comprising at least one of the compounds selected from the group consisting of triptycene and the triptycene derivatives, and a solvent.

17. A method for manufacturing a photoelectric conversion element according to claim 15, further comprising firing the formed coating film.

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