Photoelectric conversion element, photoelectric conversion module, and photoelectric conversion system

Abstract

This provides a photoelectric conversion element with stable electric polarization at the perovskite crystal grain boundaries. [Solution] The photoelectric conversion element (1) comprises a photoelectric conversion layer (2) containing a perovskite compound, a surface electrode (3) located on the light incident side of the photoelectric conversion layer (2) to extract a current generated by the photovoltaic power of the photoelectric conversion layer (2), a back electrode (4) located on the opposite side of the photoelectric conversion layer (2) from the surface electrode (3) to extract the current, a first application electrode (5) located on the opposite side of the surface electrode (3) from the photoelectric conversion layer (2) to apply an external electric field to the photoelectric conversion layer (2), and a second application electrode (6) located on the opposite side of the photoelectric conversion layer (2) from the first application electrode (5) to apply an external electric field to the photoelectric conversion layer (2).

Description

Technical Field

[0001] The present disclosure relates to a photoelectric conversion element, a photoelectric conversion module, and a photoelectric conversion system. Background Art

[0002] Photoelectric conversion elements are used, for example, in optical sensors, copying machines, solar cell modules, and the like. Among these, solar cell modules are being widely spread in earnest as a typical utilization method of renewable energy. As solar cell modules, solar cell modules using inorganic photoelectric conversion elements (for example, silicon-based solar cell modules, CIGS (Copper Indium Gallium Selenide)-based solar cell modules, and CdTe (cadmium telluride)-based solar cell modules, etc.) have been widespread.

[0003] On the other hand, as solar cell modules, solar cell modules using organic photoelectric conversion elements (for example, organic thin-film solar cell modules and dye-sensitized solar cell modules) are also being studied. Since a solar cell module using such an organic photoelectric conversion element can be manufactured by a coating process without using a vacuum process, there is a possibility that the manufacturing cost can be significantly reduced. Therefore, solar cell modules using organic photoelectric conversion elements are expected as next-generation solar cell modules.

[0004] In recent years, as organic photoelectric conversion elements, photoelectric conversion elements using a perovskite compound for a light absorption layer have been studied. Examples of the perovskite compound include lead complexes. A photoelectric conversion element using a perovskite compound for a light absorption layer is excellent in photoelectric conversion efficiency. In addition, active studies have been made to form a photoelectric conversion element by infiltrating a coating liquid of the perovskite compound into a porous multilayer structure, which is promising in terms of the light multiple scattering effect and the cell production process (Patent Document 1). Prior Art Documents Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2016-523453 [Patent Document 2] Special Publication No. 2023-523425 [Overview of the project] [Problems that the invention aims to solve]

[0006] Perovskite solar cells are known for their large electric polarization at the perovskite grain boundaries, and by effectively utilizing this characteristic, highly efficient solar cells have been realized.

[0007] However, it is known that the electric polarization at the perovskite grain boundaries is unstable, and this can lead to unstable solar cell characteristics. In other words, controlling the interfacial polarization at the perovskite grain boundaries has a significant impact on the carrier rectification characteristics at the perovskite layer interface, and controlling this interfacial polarization is key to achieving high efficiency or high reliability in solar cells.

[0008] Electronic devices are known that include a memory equipped with external electric field application electrodes that sandwich a perovskite layer (spontaneously polarizing material) above and below in order to apply an external electric field to the perovskite layer (spontaneously polarizing material), and electronic devices that include a memory that controls the polarization of a spontaneously polarizing material by dividing the external electric field application electrodes or forming the external electric field application electrodes on the side of the spontaneously polarizing material (a surface other than the top and bottom). (Patent Document 2)

[0009] However, the inventors of this invention have focused on the problem that in the external electric field application electrode described in Patent Document 2, which is formed by directly sandwiching perovskite layers above and below, carriers flowing into the external electric field application electrode flow into the interface of the perovskite layer, causing polarization reversal at this interface, making it impossible to control the desired interface polarization (stabilize electric polarization).

[0010] One aspect of this disclosure aims to realize a photoelectric conversion element, a photoelectric conversion module, and a photoelectric conversion system in which electric polarization is stable at the perovskite crystal grain boundaries. [Means for solving the problem]

[0011] To solve the above problems, a photoelectric conversion element according to one aspect of the present disclosure comprises: a photoelectric conversion layer containing a perovskite compound; a surface electrode located on the light incident side of the photoelectric conversion layer for extracting a current generated by the photovoltaic power of the photoelectric conversion layer; a back electrode located on the opposite side of the surface electrode of the photoelectric conversion layer for extracting the current; a first application electrode located on the opposite side of the surface electrode of the photoelectric conversion layer for applying an external electric field to the photoelectric conversion layer; and a second application electrode located on the opposite side of the first application electrode of the photoelectric conversion layer for applying the external electric field to the photoelectric conversion layer.

[0012] To solve the above problems, a photoelectric conversion module according to one aspect of the present disclosure integrates a plurality of photoelectric conversion elements according to one aspect of the present disclosure, and the plurality of integrated photoelectric conversion elements are sealed by a barrier layer.

[0013] To solve the above problems, a photoelectric conversion system according to one aspect of the present disclosure comprises a photoelectric conversion element according to one aspect of the present disclosure, an output control unit connected to the surface electrode and the back electrode for controlling the output of the current taken out from the surface electrode and the back electrode, and an external electric field control unit connected to the first applied electrode and the second applied electrode for controlling the direction and intensity of the external electric field. [Effects of the Invention]

[0014] According to one aspect of this disclosure, it is possible to provide a photoelectric conversion element, a photoelectric conversion module, and a photoelectric conversion system in which the electric polarization at the perovskite crystal grain boundaries is stable. [Brief explanation of the drawing]

[0015] [Figure 1] This is a cross-sectional view of a photoelectric conversion element according to Embodiment 1. [Figure 2] This is a cross-sectional view of a modified example of the photoelectric conversion element described above. [Figure 3] It is a cross-sectional view of another modified example of the above photoelectric conversion element. [Figure 4] It is a cross-sectional view of still another modified example of the above photoelectric conversion element. [Figure 5] It is a cross-sectional view for explaining the operation of the above photoelectric conversion element. [Figure 6] It is a schematic diagram showing a band structure and the flow of carriers during operation of the above photoelectric conversion element. [Figure 7] It is a cross-sectional view for explaining another operation of the above photoelectric conversion element. [Figure 8] It is a schematic diagram showing a band structure and the flow of carriers during another operation of the above photoelectric conversion element. [Figure 9] It is a cross-sectional view of the photoelectric conversion module according to Embodiment 2. [Figure 10] It is a diagram showing an equivalent circuit of a photoelectric conversion element provided in the above photoelectric conversion module. [Figure 11] It is a schematic diagram of the photoelectric conversion system according to Embodiment 3. [Figure 12] It is a graph showing output control results when an electric field is applied using the above photoelectric conversion system. [Figure 13] It is a cross-sectional view of the photoelectric conversion element according to Embodiment 4. [Figure 14] It is a cross-sectional view of another photoelectric conversion element according to Embodiment 4. [Figure 15] It is a cross-sectional view of still another photoelectric conversion element according to Embodiment 4. Mode for Carrying Out the Invention

[0016] Embodiments of this disclosure will be described below with reference to the drawings. However, this disclosure is not limited in any way to the embodiments and can be implemented with appropriate modifications within the scope of the purpose of this disclosure. In the drawings, the same or corresponding parts may be denoted by the same reference numerals and their description may be omitted. Also, the scale of each component in the drawings may not be accurate. Unless otherwise specified, each material described in the embodiments of this disclosure may be used alone or in combination of two or more types. Furthermore, in the embodiments of this disclosure, the terms "front" and "back" are for convenience only and do not specify the orientation of the front and back in actual use.

[0017] Conventional perovskite solar cells lacked a mechanism to control the polarization state when performance degradation occurred due to changes in the polarization state at the interface between the perovskite layer and the electron transport layer (ETL) / hole transport layer (HTL). This disclosure applies a gate electrode, used in dielectric memory to apply an external electric field necessary for polarization control, to solar cells. This disclosure achieves high efficiency and high reliability in perovskite solar cells by providing such an external electric field application mechanism separately from the carrier extraction electrode of conventional solar cells.

[0018] (Embodiment 1) Figure 1 is a cross-sectional view of the photoelectric conversion element 1 according to Embodiment 1.

[0019] The photoelectric conversion element 1 comprises a photoelectric conversion layer 2 including a light-absorbing portion (in this embodiment, a perovskite compound is exemplified), and a surface electrode 3 and a back electrode 4 arranged on either side of the photoelectric conversion layer 2. The photoelectric conversion element 1 may also include a surface electrode 3 located on the light incident side of the photoelectric conversion layer 2 to extract the current generated by the photovoltaic power of the photoelectric conversion layer 2. The photoelectric conversion element 1 may also include a back electrode 4 located on the opposite side of the surface electrode 3 of the photoelectric conversion layer 2 to extract this current. The photoelectric conversion element 1 may also include a first application electrode 5 located on the opposite side of the photoelectric conversion layer 2 of the surface electrode 3 to apply an external electric field to the photoelectric conversion layer 2. The photoelectric conversion element 1 may also include a second application electrode 6 located on the opposite side of the first application electrode 5 of the photoelectric conversion layer 2 to apply an external electric field to the photoelectric conversion layer 2. The second application electrode 6 may be located on the opposite side of the back electrode 4 of the photoelectric conversion layer 2. The photoelectric conversion layer 2 may further contain insulating fine particles. Furthermore, in this disclosure, unless otherwise specified, the term "layer" or "film" is not necessarily limited to having a uniform thickness or width, but also includes those with varying thicknesses, or those in a patterned or island-like form. Preferably, the layer or film has a substantially uniform thickness. Furthermore, unless otherwise specified, "approximately" or "to a certain extent" refers to the range of manufacturing tolerances, and preferentially indicates that a variation of plus 15% and minus 15% of that value is acceptable. The light-absorbing layer is a layer that can absorb light, and it absorbs light incident on the photoelectric conversion layer, generating electrons and holes. These electrons move to the electron transport layer, and the holes move to the hole transport layer. The fact that the light-absorbing layer absorbs light and generates electrons and holes is self-evident as long as the solar cell functions as a solar cell, that is, as a solar cell that performs the function of photoelectric conversion, and does not require verification. As long as a material with light-absorbing properties is included, it can be assumed that the light-absorbing layer absorbs light and generates electrons and holes.

[0020] The photoelectric conversion element 1 further comprises a first carrier transport layer 7 located between the surface electrode 3 and the photoelectric conversion layer 2, and a second carrier transport layer 8 located between the back electrode 4 and the photoelectric conversion layer 2. In this embodiment, the first carrier transport layer 7 refers to an electron-transportable layer (electron transport layer). The first carrier transport layer 7 may also be a layer with hole-blocking functionality. Furthermore, it is even more desirable if the first carrier transport layer 7 is made of a material that possesses both electron transport and hole-blocking functions. It is self-evident that, as long as a solar cell functions as a solar cell, an electron transport layer located on the electron transport side of the light-absorbing layer or on the electron transport side of the light-absorbing layer has electron transport functionality, and no verification is required. That is, as long as a solar cell functions as a solar cell for photoelectric conversion, a layer located on the electron transport side of the light-absorbing layer or on the electron transport side of the light-absorbing layer is called an electron transport layer. The electron transport side can be rephrased as the negative electrode side of the photoelectric conversion element. In this embodiment, the second carrier transport layer 8 refers to a hole transportable layer (hole transport layer). The second carrier transport layer 8 may also be a layer having an electron blocking function. Furthermore, it is even more desirable if the second carrier transport layer 8 is made of a material that possesses both hole transport and electron blocking functions. Furthermore, as long as a solar cell functions as a solar cell, it is self-evident that the hole transport layer located on the hole transport side of the light absorption layer or on the hole transport side of the light absorption layer has the function of transporting holes, and no verification is required. In other words, as long as a solar cell functions as a solar cell for photoelectric conversion, the layer located on the hole transport side of the light absorption layer or on the hole transport side of the light absorption layer is called the hole transport layer. The hole transport side can be rephrased as the positive electrode side of the photoelectric conversion element. Furthermore, the term "carrier transport layer" can simply refer to the first carrier transport layer 7, the second carrier transport layer 8, or a layer containing a material with carrier blocking functionality.

[0021] The photoelectric conversion element 1 may further include a transparent substrate 9 located between the surface electrode 3 and the first applied electrode 5, and an insulating layer 10 located between the back electrode 4 and the second applied electrode 6.

[0022] The distance between the first application electrode 5 and the second application electrode 6 is preferably 3 mm or less.

[0023] Thus, the photoelectric conversion element 1 is configured as a laminated structure in which a surface electrode 3 is formed on a transparent substrate 9, and on top of that, an electron transport layer, in this embodiment, is a first carrier transport layer 7 as a hole-blocking layer which also has a hole-blocking function, an organic photoelectric conversion layer 2 containing a perovskite compound, a hole transport layer, in this embodiment, is a second carrier transport layer 8 as an electron-blocking layer which also has an electron-blocking function, and a back electrode 4 are stacked in that order. The film thickness of the photoelectric conversion layer 2, which is made of a perovskite compound, is set to 500 nm to 1 μm, and because light can be absorbed efficiently by the light-reflecting structure made up of the above-described laminated structure, the film thickness of the photoelectric conversion layer 2 can be made thinner, thereby improving the open-circuit voltage and FF characteristics (recombination reduction).

[0024] A photoelectric conversion layer 2 containing an organic photoelectric conversion material is configured with an oxide particle distribution layer in which inorganic filler particles are dispersed. This oxide particle distribution layer enables high efficiency and improves resistance to water molecule penetration. As a result, it has the effect of suppressing local current leakage between the surface electrode 3 and the back electrode 4 formed on the transparent substrate 9, making it suitable for large-area solar cell processes.

[0025] Furthermore, when light is irradiated onto the photoelectric conversion layer 2 containing an organic photoelectric conversion material, the contact cross-sectional area between the photoelectric conversion layer 2 and the second carrier transport layer 8 is increased. By providing a photoexcited carrier separator that can efficiently extract photoexcited carriers to the back electrode 4, a solar cell with high efficiency, low cost, and high rigidity can be realized.

[0026] (Transparent base 9) Examples of the shape of the transparent substrate 9 include a flat plate, a film, and a cylindrical shape. When light is shone on the surface of the photoelectric conversion element 1 that faces the transparent substrate 9, the transparent substrate 9 is transparent. In this case, examples of the material of the transparent substrate 9 include transparent glass (more specifically, soda-lime glass and alkali-free glass, etc.) and heat-resistant transparent resin. In this disclosure, "transparent" means that light is transmitted, but this does not exclude anything that reflects or absorbs light to some extent. It is sufficient that it is provided on the light-receiving surface side of the solar cell and transmits light appropriately. As long as the solar cell is functioning as a solar cell, it can be considered equivalent to being provided on the light-receiving surface side of the photoelectric conversion element. Therefore, it can be considered transparent if it is provided at least on the light-receiving surface side of the photoelectric conversion layer of the photoelectric conversion element or on the light-receiving surface side of the photoelectric conversion layer. In the case of double-sided light reception, not only the light-receiving surface side but also the back side can be considered transparent as long as the solar cell is functioning as a solar cell, provided that it is provided on the back side of the photoelectric conversion layer of the photoelectric conversion element or on the back side of the photoelectric conversion layer.

[0027] (Surface electrode 3) The surface electrode 3 corresponds to the cathode of the photoelectric conversion element 1. The surface electrode 3 functions as an electrode for extracting the photovoltaic power of the photoelectric conversion element 1. As long as the photoelectric conversion element 1 has the function of photoelectric conversion as a solar cell, it is not necessary to check the conductive physical properties of the surface electrode 3; if it is formed from a material that is considered to be conductive, it can be identified as the surface electrode 3. Examples of materials constituting the surface electrode 3 include transparent conductive materials (particularly transparent conductive oxides (TCO)) and opaque conductive materials. Examples of transparent conductive materials include copper iodide (CuI), indium tin oxide (ITO), tin oxide (SnO2), fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), indium zinc oxide (IZO), and gallium-doped zinc oxide (GZO). Examples of opaque conductive materials include sodium, sodium-potassium alloys, lithium, magnesium, aluminum, magnesium-silver mixtures, magnesium-indium mixtures, aluminum-lithium alloys, aluminum-aluminum oxide mixtures (Al / Al2O3), and aluminum-lithium fluoride mixtures (Al / LiF).

[0028] The thickness of the surface electrode 3 is not particularly limited and should be any thickness that can exhibit the desired properties (e.g., electron transportability and transparency).

[0029] (First carrier transport layer 7 as a hole block layer) The first carrier transport layer 7, acting as a hole-blocking layer, penetrates the mesoporous stacked structure as a light-absorbing layer and transports electrons generated by photoexcitation in the photoelectric conversion layer 2, which contains a dried organic photoelectric conversion material, to the surface electrode 3, while simultaneously blocking holes generated by photoexcitation. For this reason, it is preferable that the first carrier transport layer 7 contains a material that facilitates the transfer of electrons generated in the photoelectric conversion layer 2, which contains the organic photoelectric conversion material, to the surface electrode 3. In the photoelectric conversion element 1, the first carrier transport layer 7 contains titanium oxide. Specifically, the first carrier transport layer 7 includes a dense titanium oxide layer with a relatively small porosity and a porous titanium oxide layer, which is a porous layer with a higher porosity than the dense titanium oxide layer. The dense titanium oxide layer and the porous titanium oxide layer constituting the first carrier transport layer 7 will now be described.

[0030] (Dense titanium oxide layer) Because the dense titanium oxide layer has a low porosity, the light-absorbing material (perovskite compound) used to form the organic photoelectric conversion material does not easily penetrate into the layer during the manufacturing of the photoelectric conversion element 1. Therefore, by having a dense titanium oxide layer in the photoelectric conversion element 1, contact between the light-absorbing material and the surface electrode 3 is suppressed. Furthermore, by having a dense titanium oxide layer in the photoelectric conversion element 1, contact between the surface electrode 3 and the back electrode 4, which is a factor in the decrease of electromotive force, is suppressed. The thickness of the dense titanium oxide layer is preferably 5 nm to 200 nm, and more preferably 10 nm to 100 nm. In addition, a packing density of 90% or more by mass is desirable.

[0031] (Porous titanium oxide layer) Because the porous titanium oxide layer has a high porosity, the light-absorbing material used to form the organic photoelectric conversion material easily penetrates into the pores within the layer during the manufacturing of the photoelectric conversion element 1. Therefore, by including a porous titanium oxide layer in the photoelectric conversion element 1, the contact area between the organic photoelectric conversion material and the first carrier transport layer 7, which acts as a hole-blocking layer, can be increased. This allows electrons generated by photoexcitation in the photoelectric conversion layer 2 containing the organic photoelectric conversion material to be efficiently transferred to the first carrier transport layer 7, which acts as a hole-blocking layer, and also blocks the holes. Furthermore, "dense" is also called dense material, compact, or compact material, and can be the same as or include these terms. In this disclosure, "dense" means a state in which, when observed in cross-section, there are no light-absorbing regions (in this embodiment, a perovskite compound, and hereinafter described as a perovskite compound) on one side in the thickness direction of the dense material (for example, the lower side). In other words, even if there is a perovskite compound on the upper side of the dense material, it is possible to ensure that it does not penetrate to the lower side of the dense material. Preferably, dense refers to a material with extremely small voids. Preferably, dense refers to a material with a maximum void width of less than 5 nm. Even more preferably, dense refers to a material in which perovskite compounds cannot be contained in the voids, or a material in which there are no regions in which perovskite compounds exist continuously throughout the thickness of the dense portion. In other words, density can be determined by observation using SEM (Scanning Electron Microscope) or EDX (Energy Dispersive X-ray spectroscopy) if it is found that there are no areas where the perovskite compound penetrates the thickness of the layer. In this disclosure, unless otherwise contradictory, observation by SEM is sufficient if it is observed and confirmed in a 400 nm wide cross-sectional SEM (or EDX) image. For example, if a single 400 nm wide cross-sectional SEM or EDX observation shows no areas where the perovskite compound penetrates the thickness of the layer, then that layer can be said to be dense. Furthermore, porous materials are also called porous or mesoporous materials, and may be the same as or include the same materials.In this disclosure, porous means materials that can contain perovskite compounds in their voids.However, porous materials are not limited to those that can contain perovskite compounds in their voids; they may also contain materials other than perovskite compounds that have photoelectric conversion functions in their voids.In this disclosure, unless otherwise contradictory, "voids in a certain member" means "regions in any region where a certain member is generally distributed dispersed or continuous, where a certain member is not present."For example, in a cross-sectional view of a porous member, voids can mean all parts of the cross-sectional view that are not the cross-section of the porous member, and may include parts where other members that are not porous members are provided.

[0032] Furthermore, the porous material forming the first carrier transport layer 7 as a hole-blocking layer may consist of a laminated porous structure composed of inorganic fine particles (particle size 50-200 nm) made of materials such as titanium dioxide and a binder resin. In this case, the inclusion of the binder resin allows for the formation of a network in which the inorganic fine particles (particle size 50-200 nm) are connected by the binder resin, enabling the formation of a porous layer on an organic film at low temperatures.

[0033] In the hole-blocking layer (first carrier transport layer 7), electrons need to be propagated towards the surface electrode 3. This electrical conduction requires tunnel conduction, and to increase the carrier leakage length (Fermi length λf), the doping concentration of the hole-blocking layer is set to 10. 16 / cm 3 It is necessary to be composed of highly insulating inorganic nanoparticles with a length of λf > 90 nm. For the same reason, highly insulating inorganic materials are required for the components that make up the electron blocking layer (second carrier transport layer 8), which will be explained later.

[0034] Furthermore, it is desirable that the valence band energy level (Ehbv) of the hole-blocking layer (first carrier transport layer 7) be composed of a material where Ehbv ≤ Eopv - 0.5 eV, compared to the valence band energy level (Eopv) of the organic photoelectric conversion material (photoelectric conversion layer 2). Although titanium oxide is given as a specific inorganic component, materials such as zinc oxide, alumina, and magnesium oxide, which have properties that facilitate electron propagation and easily block holes, may also be used, or mixtures of these materials or core-shelled fine particles may be used.

[0035] Furthermore, the hole block layer (first carrier transport layer 7) may be composed of tin oxide (SnO2) fine particles and a conductive organic binder resin material as described below. The thickness of the hole block layer is approximately 100 nm and may be formed by coating and drying a dispersion of SnO2 fine particles, or by sputtering a film of SnO2.

[0036] Furthermore, the surface of the hole block layer (first carrier transport layer 7) may be subjected to nitriding surface treatment with nitrogen plasma to improve the wettability of the coating liquid, taking into consideration the subsequent coating process.

[0037] (Photoelectric conversion layer 2) A perovskite compound is preferred as the photoelectric conversion layer 2. The perovskite compound is composed of a compound represented by the general formula (1) ABX3... (hereinafter sometimes referred to as perovskite compound (1)). However, while the composition ratio of each is preferably 1:1:3, it is not necessarily 1:1:3, the content of each element may be adjusted as appropriate, and each constituent element does not need to be of only one type. As long as the solar cell has a photoelectric conversion function, it has the freedom of configuration as described. In general formula (1), A is an organic molecule (including an organic group or organic cation, as is the case in this disclosure) or an inorganic atom or molecule (including an inorganic group or inorganic cation, as is the case in this disclosure) or a combination thereof, B is a metal atom or molecule (including a metal cation, as is the case in this disclosure), and X is a halogen atom or molecule or a chalcogen atom or molecule (including a halogen anion or chalcogen anion, as is the case in this disclosure). In general formula (1), the three Xs may be the same or different from each other. Perovskite compounds, by being contained in a light-absorbing layer, can absorb light and convert it into electricity, and this should be taken into consideration. In other words, it is sufficient to know that a compound is a perovskite compound if it contains, for example, organic molecules, metal atoms, and halogen atoms. Furthermore, it is sufficient to know that a compound is a perovskite compound if elements corresponding to A, B, and X are detected, as long as the solar cell has a photoelectric conversion function. For example, molecules containing carbon, nitrogen, and hydrogen are suitable as organic molecules, and therefore, it is sufficient to know that carbon, nitrogen, hydrogen, metal elements, and halogen elements or chalcogen elements are detected. Alternatively, it is sufficient to know that a compound is a perovskite compound if it contains A, B, and X, for example, if it contains inorganic atoms, metal atoms, and halogen atoms. Furthermore, it is sufficient to know that a compound is a perovskite compound if elements corresponding to A, B, and X are detected, as long as the solar cell has a photoelectric conversion function. For example, cesium or rubidium are suitable as inorganic atoms, and therefore, it is sufficient to know that cesium or rubidium, metal elements, and halogens or chalcogens are detected.Furthermore, the fact that it is a perovskite compound is based on the premise that a solar cell must have a crystalline structure in order to have a photoelectric conversion function, and therefore, confirmation of the presence of a crystalline structure is not required. The light-absorbing layer may contain materials other than perovskite compounds.

[0038] The perovskite compound (1) is an organic-inorganic hybrid compound. An organic-inorganic hybrid compound is a compound composed of an inorganic material and an organic material. The photoelectric conversion element 1, which uses the perovskite compound (1) that is an organic-inorganic hybrid compound, is also called an organic-inorganic hybrid photoelectric conversion element.

[0039] Examples of organic molecules represented by A in general formula (1) include alkylamines, alkylammonium compounds, and nitrogen-containing heterocyclic compounds. In perovskite compound (1), the organic molecule represented by A may be only one type of organic molecule, or it may be two or more types of organic molecules.

[0040] Examples of alkylamines include methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, trimethylamine, triethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, ethylmethylamine, methylpropylamine, butylmethylamine, methylpentylamine, hexylmethylamine, ethylpropylamine, and ethylbutylamine.

[0041] Alkylammonium compounds are ionized compounds of the alkylamines mentioned above. Examples of alkylammonium compounds include methylammonium (CH3NH3), ethylammonium, propylammonium, butylammonium, pentylammonium, hexylammonium, dimethylammonium, diethylammonium, dipropylammonium, dibutylammonium, dipentylammonium, dihexylammonium, trimethylammonium, triethylammonium, tripropylammonium, tributylammonium, tripentylammonium, trihexylammonium, ethylmethylammonium, methylpropylammonium, butylmethylammonium, methylpentylammonium, hexylmethylammonium, ethylpropylammonium, and ethylbutylammonium.

[0042] Examples of nitrogen-containing heterocyclic compounds include imidazole, azole, pyrrole, aziridine, azirine, azetidine, azeto, azole, imidazoline, and carbazole. Nitrogen-containing heterocyclic compounds may also be ionized. Phenethylammonium is preferred as an ionized nitrogen-containing heterocyclic compound.

[0043] The organic molecule represented by A is preferably methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, methylammonium, ethylammonium, propylammonium, butylammonium, pentylammonium, hexylammonium, or phenethylammonium, more preferably methylamine, ethylamine, propylamine, methylammonium, ethylammonium, or propylammonium, and even more preferably methylammonium.

[0044] In general formula (1), examples of metal atoms represented by B include lead, tin, zinc, titanium, antimony, bismuth, nickel, iron, cobalt, silver, copper, gallium, germanium, magnesium, calcium, indium, aluminum, manganese, chromium, molybdenum, and europium. In the perovskite compound (1), the metal atom represented by B may be only one type of metal atom or two or more types of metal atoms. From the viewpoint of improving the light absorption characteristics and charge generation characteristics of organic photoelectric conversion materials, lead atoms are preferred as the metal atom represented by B.

[0045] In general formula (1), examples of halogen atoms represented by X include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms. In perovskite compound (1), the halogen atom represented by X may be one type of halogen atom or two or more types of halogen atoms. From the viewpoint of narrowing the energy band gap of perovskite compound (1), iodine atoms are preferred as the halogen atom represented by X. More specifically, it is preferable that at least one of the three Xs represents an iodine atom, and it is more preferable that all three Xs represent iodine atoms.

[0046] As the perovskite compound (1), a compound represented by the general formula "CH3NH3PbX3 (where X represents a halogen atom)" is preferred, and CH3NH3PbI3 is more preferred. By using a compound represented by the general formula "CH3NH3PbX3" (especially CH3NH3PbI3) as the perovskite compound (1), electrons and holes can be generated more efficiently in the organic photoelectric conversion material, and as a result, the photoelectric conversion efficiency of the photoelectric conversion element 1 can be further improved.

[0047] Figure 10 shows a cross-sectional view of the film structure after the above organic photoelectric conversion materials have been permeated and crystallized.

[0048] When forming a cover layer on the surface of the photoelectric conversion layer 2, which includes the organic photoelectric conversion material on the surface side, by sputter deposition, a protective film may be formed to protect the surface of the crystallized organic photoelectric conversion material from plasma damage. The following organic resins can be used as the material for the protective film.

[0049] Examples of organic binder resins include vinyl resins such as polymethyl methacrylate, polystyrene, and polyvinyl chloride; thermoplastic resins such as polycarbonate, polyester, polyester carbonate, polysulfone, polyarylate, polyamide, methacrylic resin, acrylic resin, polyether, polyacrylamide, and polyphenylene oxide; thermosetting resins such as epoxy resin, silicone resin, polyurethane, phenolic resin, alkyd resin, melamine resin, phenoxy resin, polyvinyl butyral, and polyvinyl formal; partially crosslinked products of these resins; and copolymer resins containing two or more of the constituent units found in these resins (insulating resins such as vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin, and acrylonitrile-styrene copolymer resin). These film-forming resins can be used individually or in combination of two or more, but other resins can also be used as long as the requirements are met.

[0050] Furthermore, the organic binder resin may contain a hole transport material. Examples of hole transport materials include pyrazoline compounds, arylamine compounds, stilbene compounds, enamine compounds, polypyrrole compounds, polyvinylcarbazole compounds, polysilane compounds, butadiene compounds, polysiloxane compounds having aromatic amines in the side chain or main chain, polyaniline compounds, polyphenylenevinylene compounds, polythienenevinylene compounds, and polythiophene compounds. Butadiene compounds and bisbutadiene compounds are particularly preferred. Other examples include conductive fine particles such as carbon nanofibers and conductive polymers such as PEDOT / PSS. The hole transport material is preferably a compound that does not easily crystallize, but the composition may include an organic binder resin or plasticizer to reliably prevent crystallization of the hole transport material.

[0051] Furthermore, the following hole transport materials may be included with the organic resin.

[0052] Examples of hole transport materials include organic hole transport materials and inorganic hole transport materials. Examples of organic hole transport materials include Spiro-MeOTAD (2,2',7,7'-tetrakis"N,N-di-P-methoxyphenylamino"-9,9'-spirobifluorene), pyrazoline compounds, arylamine compounds, stilbene compounds, enamine compounds, polypyrrole compounds, polyvinylcarbazole compounds, polysilane compounds, butadiene compounds, polysiloxane compounds having aromatic amines in the side chain or main chain, polyaniline compounds, polyphenylenevinylene compounds, polythieninevinylene compounds, and polythiophene compounds. Examples of inorganic hole transport materials include carbon nanotubes and copper thiocyanate (CuSCN). Examples of carbon nanotubes include multiwalled carbon nanotubes (MWCNTs) and single-walled carbon nanotubes (SWCNTs). Carbon nanotubes are preferred as hole transport materials, and multiwalled carbon nanotubes are more preferred.

[0053] Furthermore, by adding additives such as aminovaleric acid hydroiodide, the water barrier resistance can be improved.

[0054] (Oxide particle distribution layer) The oxide particles of the inorganic filler dispersed in the perovskite compound coating solution are preferably fine particles of SiO2, Al2O3, ZrO2, ZnO, etc., with a particle size of 10 to 50 nm. The photoelectric conversion layer 2 of the perovskite compound contains an oxide particle distribution layer in which oxide particles are dispersed. When perovskite crystals are incorporated into the dispersed oxide particles, the effective refractive index on the back electrode 4 side is lowered, which efficiently reflects light to the photoelectric conversion layer, reducing light absorption loss by the back electrode 4 and realizing a high-efficiency solar cell.

[0055] (Second carrier transport layer 8 as an electron block layer) The second carrier transport layer 8, acting as an electron blocking layer, captures holes generated in the photoelectric conversion layer 2 and transports them to the back electrode 4, which is the anode, thereby blocking electrons generated in the photoelectric conversion layer 2. The second carrier transport layer 8 is a layer that has the function of moving holes generated in the light-absorbing portion to the back electrode 4. It is self-evident that, as long as the photoelectric conversion element 1 has a photoelectric conversion function, the second carrier transport layer 8 located on the hole transport side of the light-absorbing portion or on the hole transport side of the light-absorbing portion has a hole transport function, and no confirmation is required. In other words, as long as the photoelectric conversion element 1 functions as a solar cell, the layer located on the hole transport side of the light-absorbing portion (or on the positive electrode side, similarly in this disclosure) or on the hole transport side of the light-absorbing portion is called the second carrier transport layer 8. The materials constituting the electron blocking layer are those whose conduction band energy level (Eebc) is Eebc ≥ Eopc + 0.5 eV, compared to the conduction band energy level (Eopc) of the organic photoelectric conversion material. Specific examples of inorganic materials include inorganic compounds such as Cu2O, NiO, and ZnS. This allows for efficient blocking of electrons photoexcited from the photoelectric conversion layer 2 containing the organic photoelectric conversion material, thereby realizing a highly efficient solar cell.

[0056] (Backside electrode 4) The back electrode 4 corresponds to the anode of the photoelectric conversion element 1. The back electrode 4 has the function of collecting holes photoexcited in the light absorption area. As long as the photoelectric conversion element 1 has the function of photoelectric conversion as a solar cell, it is not necessary to check the conductive physical properties of the back electrode 4, and it can be confirmed as the back electrode 4 if it is formed of a material that is thought to be conductive. Examples of materials constituting the back electrode 4 include metals, transparent conductive inorganic materials, conductive fine particles, and conductive polymers (especially transparent conductive polymers). Examples of metals include gold, silver, and platinum. Examples of transparent conductive inorganic materials include copper iodide (CuI), indium tin oxide (ITO), tin oxide (SnO2), fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), indium zinc oxide (IZO), and gallium-doped zinc oxide (GZO). Examples of conductive fine particles include silver nanowires and carbon nanofibers. Examples of transparent conductive polymers include polymers containing poly(3,4-ethylenedioxythiophene) and polystyrene sulfonic acid (PEDOT / PSS).

[0057] In order to efficiently apply the built-in potential to the photoelectric conversion layer 2, it is desirable to form a metal with a work function φ ≥ 5.0 eV as the back electrode 4. This creates a structure in which electrons are extracted from the transparent conductive film formed on the transparent substrate 9 side and holes are extracted from the back electrode 4 side. This enables a smooth flow of holes at the interface between the electron blocking layer (second carrier transport layer 8) on the hole extraction side and the back electrode 4, resulting in a highly efficient solar cell.

[0058] (1st application electrode 5) The first applied electrode 5 is formed on the light incident side of the surface electrode 3 and is connected to the transparent substrate 9 via an insulating material. The light incident side of the first applied electrode 5 is also covered with an insulator and is equipped with a terminal that can be connected to the external electric field control unit 14 (Figure 11). Examples of materials that constitute the first applied electrode 5 include transparent conductive materials (particularly transparent conductive oxides (TCO)) and opaque conductive materials. Examples of transparent conductive materials include copper iodide (CuI), indium tin oxide (ITO), tin oxide (SnO2), fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), indium zinc oxide (IZO), and gallium-doped zinc oxide (GZO). Examples of opaque conductive materials include sodium, sodium-potassium alloy, lithium, magnesium, aluminum, magnesium-silver mixture, magnesium-indium mixture, aluminum-lithium alloy, aluminum-aluminum oxide mixture (Al / Al2O3), and aluminum-lithium fluoride mixture (Al / LiF).

[0059] The film thickness of the first applied electrode 5 is not particularly limited and should be any thickness that can exhibit the desired properties (e.g., electron transportability and transparency).

[0060] (Second application electrode 6) The second applied electrode 6 is formed on the back side of the back electrode 4 opposite to the light incidence side, and is connected to the back electrode 4 via an insulating layer 10. The back side of the second applied electrode 6 is also covered with an insulator and is equipped with a terminal that can be connected to the external electric field control unit 14. Examples of materials that constitute the second applied electrode 6 include transparent conductive materials (particularly transparent conductive oxides (TCO)) and opaque conductive materials. Examples of transparent conductive materials include copper iodide (CuI), indium tin oxide (ITO), tin oxide (SnO2), fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), indium zinc oxide (IZO), and gallium-doped zinc oxide (GZO). Examples of opaque conductive materials include sodium, sodium-potassium alloy, lithium, magnesium, aluminum, magnesium-silver mixture, magnesium-indium mixture, aluminum-lithium alloy, aluminum-aluminum oxide mixture (Al / Al2O3), and aluminum-lithium fluoride mixture (Al / LiF).

[0061] The film thickness of the second applied electrode 6 is not particularly limited and should be any thickness that can exhibit the desired characteristics.

[0062] Figure 2 is a cross-sectional view of a modified photoelectric conversion element 1A. Components similar to those described above are given the same reference numerals. A detailed explanation of these components will not be repeated.

[0063] The photoelectric conversion element 1A comprises a first carrier transport layer 7A located between the surface electrode 3 and the photoelectric conversion layer 2, and a second carrier transport layer 8A located between the back electrode 4 and the photoelectric conversion layer 2. The first carrier transport layer 7A includes a hole transport material and an electron blocking material. The second carrier transport layer 8A includes an electron transport material and a hole blocking material.

[0064] The difference from the photoelectric conversion element 1 in Figure 1 is that the first carrier transport layer 7A is placed on the incident light side of the photoelectric conversion layer 2 as an electron blocking layer, and the second carrier transport layer 8A is placed on the back side as a hole blocking layer insulating layer, resulting in an inverse junction type perovskite solar cell.

[0065] Figure 3 is a cross-sectional view of a photoelectric conversion element 1B relating to another modified example.

[0066] The photoelectric conversion element 1B includes a second application electrode 6B located on the opposite side of the first application electrode 5 of the photoelectric conversion layer 2 in order to apply an external electric field to the photoelectric conversion layer 2. This second application electrode 6B is shared with the back electrode located on the opposite side of the front electrode 3 of the photoelectric conversion layer 2 in order to extract the current generated by the photovoltaic force of the photoelectric conversion layer 2. The difference from the photoelectric conversion element 1 in Figure 1 is that the back electrode 4 and the second application electrode 6 are shared to form the second application electrode 6B, and the element configuration is simplified.

[0067] Figure 4 is a cross-sectional view of a photoelectric conversion element 1C according to yet another modified example.

[0068] The photoelectric conversion element 1C comprises a first carrier transport layer 7A containing a hole transport material and an electron blocking material, a second carrier transport layer 8A containing an electron transport material and a hole blocking material, and a second application electrode 6B which is shared with the back electrode. The difference from the photoelectric conversion element 1A in Figure 2 is that the back electrode 4 and the second application electrode 6 are shared to form the second application electrode 6B, simplifying the element configuration.

[0069] Figure 5 is a cross-sectional view illustrating the operation of the photoelectric conversion element 1.

[0070] Figure 5 shows the polarization state of the photoelectric conversion layer 2 of the photoelectric conversion element 1. By introducing a potential difference between the first application electrode 5 and the second application electrode 6, an external electric field E is applied from the back electrode 4 to the front electrode 3. This case is defined as the application of a positive external electric field. The photoelectric conversion layer 2 is positively polarized between it and the hole block layer (first carrier transport layer 7), and negatively polarized between it and the electron block layer (second carrier transport layer 8).

[0071] Figure 6 is a schematic diagram showing the band structure and carrier flow during operation of the photoelectric conversion element 1.

[0072] The polarization introduced at both interfaces of the photoelectric conversion layer 2 is thought to cause band bending near the interface of the photoelectric conversion layer 2, thereby improving the carrier rectification characteristics at the interface.

[0073] Figure 7 is a cross-sectional view illustrating other operations of the photoelectric conversion element 1.

[0074] Figure 7 shows the polarization state of the photoelectric conversion layer 2 of the photoelectric conversion element 1. By introducing a potential difference between the first application electrode 5 and the second application electrode 6, an external electric field E is applied from the surface electrode 3 to the back electrode 4. This case is defined as the application of a negative external electric field. Between the photoelectric conversion layer 2 and the hole block layer (first carrier transport layer 7), a portion of the positively polarized area reverses to become negative, and conversely, between the photoelectric conversion layer 2 and the electron block layer (second carrier transport layer 8), a region appears where a portion of the negative polarization reverses to become positive.

[0075] Figure 8 is a schematic diagram showing the band structure and carrier flow of the photoelectric converter 1 during other operating conditions.

[0076] As the polarization introduced at both interfaces of the photoelectric conversion layer 2 weakens, the band bending near the interface of the photoelectric conversion layer 2 decreases. However, it is thought that the rectification characteristics improve because the carrier extraction efficiency at the interface improves in the direction of the external electric field E.

[0077] Furthermore, for photoelectric conversion element 1A in Figure 2 and photoelectric conversion element 1C in Figure 4, although the definition of the direction of applied external electric field is reversed, the same improvement effect on carrier rectification characteristics due to applied external electric field as described above can be observed.

[0078] (Embodiment 2)

[0079] Figure 9 is a cross-sectional view of the photoelectric conversion module 11 according to Embodiment 2.

[0080] The photoelectric conversion module 11 integrates multiple photoelectric conversion elements 1. These integrated photoelectric conversion elements 1 are then sealed by barrier layers 111 and 121.

[0081] The photoelectric conversion module 11 comprises a plurality of photoelectric conversion elements 1 connected in series. The plurality of photoelectric conversion elements 1 include a transparent substrate 9, a plurality of surface electrodes 3 provided on the transparent substrate 9, a plurality of photoelectric conversion layers 2 provided on each of the plurality of surface electrodes 3, a plurality of back electrodes 4 provided on each of the plurality of photoelectric conversion layers 2, and an insulating layer 10 provided to cover the sides of the photoelectric conversion layers 2. The photoelectric conversion layers 2 are filled and crystallized with an organic photoelectric conversion material. A hole block layer (first carrier transport layer 7), a photoelectric conversion layer 2, and an electron block layer (second carrier transport layer 8) are provided. The insulating layer 10 is characterized by being a dense inorganic material layer.

[0082] The photoelectric conversion module 11 (series-connected solar cell) of this embodiment comprises a plurality of photoelectric conversion elements 1, a first terminal 122, and a second terminal 112. The plurality of photoelectric conversion elements 1 are connected in series. One end of the series-connected plurality of photoelectric conversion elements 1 is connected to the first terminal 122, and the other end of the photoelectric conversion element 100 is connected to the second terminal 112. The photoelectric conversion module 11 may also be a solar cell module. The number of photoelectric conversion elements 1 connected in series is not particularly limited, as long as there are multiple elements.

[0083] The transparent substrate 9 is a substrate for forming the photoelectric conversion layer 2. The transparent substrate 9 may be a substrate for a series-connected solar cell or a substrate for a solar cell module. If the solar cell module has multiple photoelectric conversion modules 11, the multiple photoelectric conversion modules 11 may be provided on a single transparent substrate 9.

[0084] When the transparent substrate 9 is on the light incidence side, the transparent substrate 9 is made of a light-transmitting material. The transparent substrate 9 may be a glass substrate or a transparent organic film. This allows light to enter the interior of the photoelectric conversion element 1. If the transparent substrate 9 is a flexible organic film, the solar cell module becomes a flexible solar cell module.

[0085] Examples of materials for the organic film that forms the transparent substrate 9 include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), polyetherimide (PEI), polytetrafluoroethylene (PTFE), polyamideimide (PAI), and polyethylene naphthalate (PEN), but other resins can also be used as long as they meet the requirements. The thickness of the organic film that forms the transparent substrate 9 is preferably 50 to 100 μm.

[0086] If the transparent substrate 9 is a transparent organic film, a barrier layer 121 may be provided on one of the main surfaces of the transparent substrate 9. The barrier layer 121 is a layer of a material with high gas barrier properties. This prevents deterioration of the inside of the photoelectric conversion element 1 due to moisture and oxygen in the air. The barrier layer 121 is also a layer of an insulating material. This suppresses the flow of leakage current. The thickness of the barrier layer 121 can be several tens to 100 nm. This allows the barrier layer 121 to be translucent. The photoelectric conversion element 1 can also be flexible. Specific examples of materials for the barrier layer 121 include silicon oxide and aluminum oxide. As long as the barrier layer 121 has gas barrier properties, insulating properties, and translucency, other oxidizing substances and insulators can also be used as materials for the barrier layer 121. Main film deposition methods for the barrier layer 121 include sputter deposition and vacuum deposition.

[0087] The surface electrode 3 is provided on the transparent substrate 9 (or on the barrier layer 121) and is an electrode for extracting the current generated by the photovoltaic power of the photoelectric conversion layer 2 of the photoelectric conversion element 1. When the transparent substrate 9 is on the light incident side, the surface electrode 3 can be a transparent conductive film. The transparent conductive film is composed of a conductive transparent material such as aluminum-doped zinc oxide (AZO), indium zinc oxide (IZO), gallium-doped zinc oxide (GZO), fluorine-doped tin oxide (FTO), or indium tin oxide (ITO). Alternatively, the surface electrode 3 may have a configuration in which fine wires of a conductive metal such as silver are patterned on an oxide such as the conductive transparent material.

[0088] Preferably, the sheet resistance of the surface electrode 3 is 10 Ω / sq or less, and the light transmittance of the surface electrode 3 is 30% or more. Methods for forming the surface electrode 3 include sputtering, vacuum deposition, conductive paste coating / printing technology, and low-temperature firing technology.

[0089] When multiple photoelectric conversion elements 1 are provided on a transparent substrate 9, the transparent conductive film formed on the transparent substrate 9 is divided for each photoelectric conversion element 1. For example, the photoelectric conversion module 11, which is a series-connected solar cell shown in Figure 9, contains five photoelectric conversion elements 1, so the transparent conductive film is divided and five surface electrodes 3 are formed. The groove separating two adjacent surface electrodes 3 may be filled with a photoelectric conversion layer 2 or the like.

[0090] The transparent substrate 9, an organic film, has a first terminal 122 formed on it, which is a photoelectric conversion module 11, a series-connected solar cell. A portion of the first terminal 122 penetrates the organic film (transparent substrate 9) and the barrier layer 121, and contacts or electrically connects to the surface electrode 3 of the end photoelectric conversion element 1 of the multiple photoelectric conversion elements 1 connected in series. Using this first terminal 122, the current generated by the photovoltaic power of the series-connected solar cell (photoelectric conversion module 11) can be extracted. A SnZn-based solder paste is an example of a material for the first terminal 122. Other conductive pastes and electrode materials can also be used as long as they meet the requirements.

[0091] The photoelectric conversion layer 2 is a layer in which light energy is converted into electrical energy. Specifically, a photovoltaic force is generated when the photoelectric conversion layer 2 receives light. The photoelectric conversion layer 2 is provided on the surface electrode 3 and is filled with and crystallized organic photoelectric conversion material 50. The photoelectric conversion layer 2 is sandwiched between a hole-blocking layer (first carrier transport layer 7) and an electron-blocking layer (second carrier transport layer 8).

[0092] The first carrier transport layer 7 is a layer that transports electrons generated by photoexcitation in the photoelectric conversion layer 2 to the surface electrode 3. Therefore, the first carrier transport layer 7 is made of a material that allows electrons generated in the photoelectric conversion layer 2 to easily move to the first carrier transport layer 7, and allows electrons from the first carrier transport layer 7 to easily move to the surface electrode 3. The first carrier transport layer 7 may also be a seed layer for oriented growth of the organic photoelectric conversion material inside the photoelectric conversion layer 2. This can improve the crystal quality of the compound having a perovskite crystal structure that constitutes the photoelectric conversion layer 2. The first carrier transport layer 7 is, for example, a titanium oxide (TiO2) layer. Furthermore, the surface of the titanium oxide contained in this titanium oxide layer may have a TiN layer or TiO 2-x N x A layer may be formed.

[0093] For example, on a transparent conductive film that will serve as the surface electrode 3, a TiN(NaCl structure) layer with a thickness of 5 to 30 nm may be formed on the surface of the TiO2 porous titanium oxide layer as a seed layer that will serve as the first carrier transport layer 7 by surface modification treatment with nitrogen plasma.

[0094] The lattice constants of TiO2 (rutile structure) and TiN (NaCl structure) are relatively well matched, and a good interface with few defects is formed between the TiO2 layer composed of TiO2 and the TiN layer composed of TiN. Near the interface, the mixed crystal material TiO 2-x N xThe formation of this layer causes the lattice constant to change continuously, suppressing the occurrence of interface defects. When the TiN layer is exposed to air after surface modification treatment with nitrogen plasma, a re-oxidation layer several nanometers thick is formed on the surface. However, because the formed TiO2 layer is thin, structural relaxation of the lattice constant does not occur, and the lattice constant of the underlying TiN layer is maintained.

[0095] After a transparent conductive film (surface electrode 3) is formed on an organic film (transparent substrate 9) covered with a barrier layer 121, an incision (L1) is made in the transparent conductive film (surface electrode 3) by laser scribing in order to separate and form a photoelectric conversion layer 2 on the organic film (transparent substrate 9). A laser wavelength in the infrared region is preferable. For example, as shown in Figure 9, an incision (L1) is made in the transparent conductive film to form the surface electrode 3. No incisions are made in the barrier layer 121.

[0096] For example, a perovskite structure compound can be formed on a transparent substrate 9 that has been cut (L1) by laser scribing, thereby forming a photoelectric conversion layer 2.

[0097] Perovskite compounds have a basic unit cell in the tetragonal system. This basic unit cell comprises organic groups (organic molecules) A ​​located at each vertex, metal atoms B located at the body center, and halogen atoms X located at the face center, and is represented by the general formula AB-X3.

[0098] The perovskite compound used to form the photoelectric conversion layer 2 can be synthesized using the compound represented by AX and the compound represented by BX2 as raw materials. Specifically, the compound having a perovskite structure can be synthesized by mixing the AX solution and the BX2 solution and heating and stirring (one-step method). Alternatively, the compound having a perovskite structure can be synthesized by applying the BX2 solution to form a coating film, applying the AX solution on the coating film, and reacting BX2 with AX (two-step method). Both the one-step and two-step methods can be used to form the photoelectric conversion layer 2 (the layer of the compound having a perovskite structure). The coating method is not particularly limited, but examples include screen printing, immersion coating, and inkjet printing.

[0099] Examples of organic solvents (contained in the coating solution) used in the coating method for forming the photoelectric conversion layer 2 include aromatic hydrocarbons such as toluene, xylene, mesitylene, tetralin, diphenylmethane, dimethoxybenzene, and dichlorobenzene; halogenated hydrocarbons such as dichloromethane, dichloroethane, and tetrachloropropane; ethers such as tetrahydrofuran (THF), dioxane, dibenzyl ether, dimethoxymethyl ether, and 1,2-dimethoxyethane; ketones such as methyl ethyl ketone, cyclohexanone, acetophenone, and isophorone; esters such as methyl benzoate, ethyl acetate, and butyl acetate; sulfur-containing solvents such as diphenyl sulfide; fluorinated solvents such as hexafluoroidisopropanol; aprotic polar solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide; alcohols such as methanol, ethanol, and isopropanol; and glyme solvents such as ethylene glycol and diethylene glycol monomethyl ether. These can be used individually or as mixed solvents. These solvents may contain water. Among these solvents, non-halogenated organic solvents are preferably used out of consideration for the global environment.

[0100] In addition, the coating solution may also contain additives such as antioxidants, viscoelastic modifiers, preservatives, and curing catalysts.

[0101] The application method is not particularly limited, but for example, immersion application, spray application, slide hopper application, etc. are preferred.

[0102] After the photoelectric conversion layer 2 is formed, a cut (L2) is made in a portion of the photoelectric conversion layer 2 by laser scribing in order to connect the surface electrode 3 of one of the two adjacent photoelectric conversion elements 1 to the electron blocking layer (second carrier transport layer 8) and back electrode 4 of the other photoelectric conversion element 1. The wavelength of the laser used is preferably in the visible light region. For example, as shown in Figure 9, a cut (L2) is made in the photoelectric conversion layer 2, and the photoelectric conversion layer 2 is formed. In this laser scribing, the photoelectric conversion layer 2 is removed, but the surface electrode 3 and barrier layer 121 are not removed.

[0103] The back electrode 4 is provided on the photoelectric conversion layer 2 and is an electrode for extracting the current generated by the photovoltaic power of the photoelectric conversion layer 2 of the photoelectric conversion element 1. The back electrode 4 is, for example, a metal film with a work function of 5 eV or more. Because the back electrode 4 is made of a metal with a deep work function (5 eV or more), a band structure bend occurs at the interface between the photoelectric conversion layer 2 and the back electrode 4, which allows for a smooth flow of holes. Examples of materials for the back electrode 4 include metals such as Ni, Pt, and Pd. The film thickness of the back electrode 4 is preferably 50 nm to 150 nm. The photoelectric conversion layer 2 or the back electrode 4 can be formed by sputtering or vacuum deposition.

[0104] After the back electrode 4 is formed, cuts (L3) are made in the electron blocking layer (second carrier transport layer 8) and a portion of the back electrode 4 by laser scribing in order to form a series connection circuit of adjacent photoelectric conversion elements 1 on the transparent substrate 9. In addition, cuts (L4) are made in the hole blocking layer (first carrier transport layer 7), photoelectric conversion layer 2, electron blocking layer (second carrier transport layer 8), and back electrode 4 in order to make the insulating layer 10, described later, function as a varistor 90 (Figure 10). The wavelength of the laser used is preferably in the ultraviolet region. For example, as shown in Figure 9, cuts (L3) are made in the electron blocking layer (second carrier transport layer 8) and the back electrode 4, and the electron blocking layer (second carrier transport layer 8) and the back electrode 4 are formed. Also, as shown in Figure 9, cuts (L4) for forming the varistor 90 (Figure 10) can be formed. Note that if the portion with cuts (L3) functions as the varistor 90, cuts (L4) can be omitted.

[0105] The insulating layer 10 is a dense inorganic material layer and is provided to cover the sides of the photoelectric conversion layer 2. The insulating layer 10 can also be provided to cover the entire periphery of the photoelectric conversion layer 2. Furthermore, the insulating layer 10 can be provided to cover the upper surface of the back electrode 4. This insulating layer 10 prevents moisture (such as water vapor) from entering the photoelectric conversion layer 2, thereby preventing degradation of the photoelectric conversion element 1. Additionally, because the insulating layer 10 is a dense inorganic material layer, it can prevent the barrier function of the insulating layer 10 from degrading due to ultraviolet light, temperature changes, etc. Furthermore, by completely coating the photoelectric conversion layer 2 with the insulating layer 10, surface electrode 3, transparent substrate 9, and barrier layer 121, the barrier properties against water vapor can be improved.

[0106] The insulating layer 10 may, for example, contain zinc oxide (ZnO) as the main material and may include silicon oxide, aluminum oxide, titanium oxide, etc. as additive materials. α (where K is the element's intrinsic constant and α is the voltage nonlinearity coefficient), it is desirable that α = 20 to 60 and the inflection point voltage be 2V or higher.

[0107] The substrate 110 is a substrate placed on top of the insulating layer 10, and the photoelectric conversion layer 2 is located between the transparent substrate 9 and the substrate 110. The substrate 110 may be the substrate for the photoelectric conversion module 11, or it may be the substrate for the solar cell module. The substrate 110 may be a glass substrate, a transparent organic film, or an opaque organic film.

[0108] If the substrate 110 is an organic film, a barrier layer 111 may be provided on one of the main surfaces of the substrate 110. The barrier layer 111 is a layer of material with high gas barrier properties. This prevents deterioration of the inside of the photoelectric conversion element 1 due to moisture and oxygen in the air. The barrier layer 111 is also a layer of insulating material. This suppresses the flow of leakage current. The thickness of the barrier layer 111 can be several tens to 100 nm. Specific examples of materials for the barrier layer 111 include silicon oxide and aluminum oxide.

[0109] The organic film substrate 110 has a second terminal 112 of the photoelectric conversion module 11 formed on it. A portion of the second terminal 112 penetrates the organic film (substrate 110) and the barrier layer 111, contacting or connecting to the back surface electrodes 4 of the photoelectric conversion elements 1 at the ends of multiple photoelectric conversion elements 1 connected in series, or connecting via the insulating layer 10. The current generated by the photovoltaic power of the photoelectric conversion module 11 can be extracted using the first terminal 122 and the second terminal 112. SnZn-based solder paste is an example of a material for the second terminal 112. Other conductive pastes and electrode materials can also be used as long as they meet the requirements.

[0110] After forming an insulating layer 10 on the back electrode 4, an organic film (substrate 110) with a second terminal 112 formed on it is bonded to the insulating layer 10 via a laminate sheet, and then heat-laminated to complete a photoelectric conversion module 11 or solar cell module in which multiple photoelectric conversion elements 1 are connected in series. The laminate sheet sandwiched between the insulating layer 10 and the substrate 110 is perforated where the second terminal 112 is located. Therefore, the second terminal 112 and the insulating layer 10 are well connected during lamination. This forms a varistor between the back electrode 4 and the second terminal 112. During power generation, a high voltage is applied between the back electrode 4 and the second terminal 112, and due to its varistor characteristics, this does not hinder current extraction. Furthermore, the back electrode 4 and the second terminal 112 may be in contact.

[0111] For the laminate sheet, any general laminating material is acceptable, but a resin film with a lamination temperature of 130°C or lower and high water resistance is preferable.

[0112] Figure 10 shows the equivalent circuit of the photoelectric conversion element 1 provided in the photoelectric conversion module 11.

[0113] As shown in Figure 10, the photoelectric conversion layer 2 can be represented by a current source 81 and a diode 82. In addition, the insulating layer 10 in the cutout (L4) is represented by a varistor 90, and this varistor 90 is connected to the surface electrode 3 and the back electrode 4 in parallel with the photoelectric conversion layer 2.

[0114] (Embodiment 3) Figure 11 is a schematic diagram of the photoelectric conversion system 12 according to Embodiment 3.

[0115] The front electrode 3 and back electrode 4 of the photoelectric conversion element 1 are connected to the respective electrodes of the output control unit 13, allowing for output control. Furthermore, the first application electrode 5 and the second application electrode 6 are connected to the external electric field control unit 14, allowing for control of the direction and intensity of the external electric field. Specifically, when the distance between the first application electrode 5 and the second application electrode 6 is 3 mm and a potential of 300 V is applied to the second application electrode 6, an electric field of 100 kV / m can be applied to the photoelectric conversion element 1. For external electric field control, shortening the distance between the first application electrode 5 and the second application electrode 6 allows for the application of a higher external electric field to the second application electrode 6 even at a lower potential.

[0116] Figure 12 is a graph showing the output control results when an electric field is applied using the photoelectric conversion system 12.

[0117] The top graph shows the maximum output tracking results for cases where the external electric field is zero and when a positive and negative 100kV / m is applied. The middle graph shows the voltage value at each case, and the bottom graph shows the current value at each case. It can be seen that the output is greater when a positive and negative external electric field is applied compared to when the external electric field is zero.

[0118] (Embodiment 4) Figure 13 is a cross-sectional view of the photoelectric conversion element 1D according to Embodiment 4.

[0119] The photoelectric conversion element 1D represents a two-terminal crystalline silicon-based tandem photoelectric conversion element. The photoelectric conversion element 1D includes a photoelectric conversion layer 2D (another photoelectric conversion layer) located between the photoelectric conversion layer 2 and the back electrode 4. The photoelectric conversion layer 2D includes a silicon-based photoelectric conversion element. The photoelectric conversion layer 2D includes an N-type silicon doped layer 15 and a P-type silicon substrate 16.

[0120] The photoelectric conversion element 1D has a first application electrode 5 positioned on the incident light side, a perovskite solar cell formed via a transparent substrate 9, a crystalline Si solar cell formed on the back side, and a second application electrode 6 formed on the back side via an insulating layer 10. The back electrode 4 and the second application electrode 6 may be common to each other, in which case the element configuration is simplified.

[0121] Furthermore, instead of crystalline Si solar cells, perovskite solar cells with a similar light absorption wavelength edge (band gap Eg) may be formed, and high efficiency can also be achieved with compound solar cells such as CIGS solar cells. Thus, the photoelectric conversion layer 2D may contain a perovskite compound or a CIGS compound.

[0122] Figure 14 is a cross-sectional view of another photoelectric conversion element 1E according to Embodiment 4.

[0123] The difference between photoelectric conversion element 1E and photoelectric conversion element 1D is that the photoelectric conversion layer 2 has an electron blocking layer (second carrier transport layer 8) on the incident light side and a hole blocking layer (first carrier transport layer 7) on the back side, making it an inverse junction type perovskite solar cell. Photoelectric conversion element 1E includes a photoelectric conversion layer 2E. The photoelectric conversion layer 2E includes a P-type silicon doped layer 15E and an N-type silicon substrate 16E.

[0124] Figure 15 is a cross-sectional view of yet another photoelectric conversion element 1F according to Embodiment 4.

[0125] The photoelectric conversion element 1F includes a photoelectric conversion layer 2F (another photoelectric conversion layer) located between the back electrode 4 and the second applied electrode 6. The photoelectric conversion element 1F further includes a surface electrode 3F (another surface electrode) located on the light incident side of the photoelectric conversion layer 2F in order to extract other currents generated by the photovoltaic power of the photoelectric conversion layer 2F, and a back electrode 4F (another back electrode) located on the opposite side of the surface electrode 3F of the photoelectric conversion layer 2F in order to extract the other currents.

[0126] The photoelectric conversion element 1F is a 4-terminal tandem type photoelectric conversion element. In the photoelectric conversion element 1F, the first application electrode 5 is positioned on the incident light side, a perovskite solar cell is formed via a transparent substrate 9, a crystalline silicon solar cell is formed on the back side of the perovskite solar cell, and a second application electrode 6 is formed on the back side via an insulating layer 10. External extraction electrodes are formed from the two stacked perovskite solar cells and the crystalline silicon solar cell, allowing output to be extracted from each of the two solar cells.

[0127] Furthermore, instead of crystalline Si solar cells, perovskite solar cells with a similar light absorption wavelength edge (band gap Eg) may be formed, and high efficiency can also be achieved with compound solar cells such as CIGS solar cells. Thus, the photoelectric conversion layer 2F may contain a perovskite compound or a CIGS compound.

[0128] [Note] A photoelectric conversion element according to Embodiment 1 of the present disclosure comprises: a photoelectric conversion layer containing a perovskite compound; a surface electrode located on the light incident side of the photoelectric conversion layer for extracting a current generated by the photovoltaic power of the photoelectric conversion layer; a back electrode located on the opposite side of the surface electrode of the photoelectric conversion layer for extracting the current; a first application electrode located on the opposite side of the surface electrode of the photoelectric conversion layer for applying an external electric field to the photoelectric conversion layer; and a second application electrode located on the opposite side of the first application electrode of the photoelectric conversion layer for applying the external electric field to the photoelectric conversion layer.

[0129] According to the above configuration, an external electric field is applied to the photoelectric conversion layer containing a perovskite compound, from which the current generated by the photovoltaic force is extracted by the surface electrode and the back electrode, by a first applied electrode located on the opposite side of the surface electrode from the photoelectric conversion layer, and a second applied electrode located on the opposite side of the photoelectric conversion layer from the first applied electrode. As a result, the electric polarization at the perovskite grain boundaries is stabilized.

[0130] In the photoelectric conversion element according to Embodiment 2 of the present disclosure, in Embodiment 1, it is preferable that the second applied electrode is located on the side of the back electrode opposite to the photoelectric conversion layer.

[0131] With the above configuration, an external electric field can be applied to the photoelectric conversion layer by the second application electrode located on the opposite side of the photoelectric conversion layer of the back electrode and the first application electrode located on the opposite side of the photoelectric conversion layer of the front electrode. A photoelectric conversion element according to aspect 3 of the present disclosure comprises a photoelectric conversion layer containing a perovskite compound, a surface electrode and a back electrode arranged on either side of the photoelectric conversion layer, a carrier transport layer disposed between the surface electrode and the back electrode, a first application electrode located on the opposite side of the surface electrode from the photoelectric conversion layer, and a second application electrode located on the opposite side of the photoelectric conversion layer from the first application electrode.

[0132] In the photoelectric conversion element according to embodiment 4 of this disclosure, it is preferable that the second applied electrode is shared with the back electrode in embodiment 1 or 3.

[0133] According to the above configuration, the second applied electrode is shared with the back electrode, thus simplifying the configuration of the photoelectric conversion element.

[0134] In any one embodiment of embodiments 1 to 4 above, the photoelectric conversion element preferably further comprises a first carrier transport layer located between the surface electrode and the photoelectric conversion layer, and a second carrier transport layer located between the back electrode and the photoelectric conversion layer.

[0135] With the above configuration, carriers generated by photoexcitation in the photoelectric conversion layer can be efficiently extracted to the surface electrode by the first carrier transport layer, and then efficiently extracted to the back electrode by the second carrier transport layer.

[0136] In the photoelectric conversion element according to aspect 6 of the present disclosure, it is preferable that in aspect 5, the first carrier transport layer includes an electron transport material and a hole blocking material, and the second carrier transport layer includes a hole transport material and an electron blocking material.

[0137] With the above configuration, electrons generated by photoexcitation of the photoelectric conversion layer can be efficiently extracted to the surface electrode by the first carrier transport layer, and holes generated by photoexcitation of the photoelectric conversion layer can be efficiently extracted to the back electrode by the second carrier transport layer.

[0138] In the photoelectric conversion element according to embodiment 7 of the present disclosure, it is preferable that the first carrier transport layer comprises a hole transport material and an electron blocking material, and the second carrier transport layer comprises an electron transport material and a hole blocking material, in embodiment 5 above.

[0139] With the above configuration, holes generated by photoexcitation of the photoelectric conversion layer can be efficiently extracted to the surface electrode by the first carrier transport layer, and electrons generated by photoexcitation of the photoelectric conversion layer can be efficiently extracted to the back electrode by the second carrier transport layer.

[0140] In any one embodiment of embodiments 1 to 7, the photoelectric conversion element preferably further comprises a transparent substrate located between the surface electrode and the first applied electrode, and an insulating layer located between the back electrode and the second applied electrode.

[0141] According to the above configuration, an external electric field can be applied to the photoelectric conversion layer via the transparent substrate by the first application electrode, and via the insulating layer by the second application electrode.

[0142] In any one embodiment of embodiments 1 to 8, the photoelectric conversion element preferably further comprises another photoelectric conversion layer located between the photoelectric conversion layer and the back electrode, or between the back electrode and the second applied electrode.

[0143] According to the above configuration, a tandem type photoelectric conversion element can be realized by a photoelectric conversion layer and another photoelectric conversion layer located between the photoelectric conversion layer and the back electrode, or between the back electrode and the second applied electrode.

[0144] In the photoelectric conversion element according to embodiment 10 of this disclosure, it is preferable that the other photoelectric conversion layer in embodiment 9 includes a Si-based photoelectric conversion element.

[0145] According to the above configuration, by including a Si-based photoelectric conversion element in the other photoelectric conversion layer, a tandem type photoelectric conversion element consisting of a photoelectric conversion layer containing a perovskite compound and a Si-based photoelectric conversion layer can be realized.

[0146] In the photoelectric conversion element according to embodiment 11 of the present disclosure, it is preferable that the other photoelectric conversion layer in embodiment 9 contains a perovskite compound or a CIGS compound.

[0147] According to the above configuration, a tandem photoelectric conversion element can be realized comprising a photoelectric conversion layer containing a perovskite compound and a photoelectric conversion layer containing a perovskite compound or a CIGS compound.

[0148] The photoelectric conversion element according to aspect 12 of the present disclosure is preferably, in aspect 9 above, the other photoelectric conversion layer is located between the back electrode and the second applied electrode, and further comprises another surface electrode located on the light incident side of the other photoelectric conversion layer for extracting another current generated by the photovoltaic power of the other photoelectric conversion layer, and another back electrode located on the opposite side of the other surface electrode of the other photoelectric conversion layer for extracting the other current.

[0149] According to the above configuration, a four-terminal tandem photoelectric conversion element can be realized, consisting of a surface electrode, a back electrode, another surface electrode, and another back electrode.

[0150] In the photoelectric conversion element according to embodiment 13 of the present disclosure, it is preferable that the photoelectric conversion layer further includes insulating fine particles in any one embodiment of embodiments 1 to 12.

[0151] According to the above configuration, the electric field generated from the first and second application electrodes formed on the outside of the surface and back electrodes for extracting carriers can be applied to the perovskite layer by penetrating the surface and back electrodes that sandwich the photoelectric conversion layer 2, which includes the perovskite layer. By providing an external electric field introduction mechanism separately from conventional carrier extraction electrodes, it is possible to provide a photoelectric conversion element that achieves high efficiency and high reliability in perovskite solar cells.

[0152] In the photoelectric conversion element according to embodiment 14 of the present disclosure, it is preferable that the distance between the first applied electrode and the second applied electrode is 3 mm or less in any one embodiment of embodiments 1 to 13.

[0153] With the above configuration, since the distance between the first applied electrode and the second applied electrode is 3 mm or less, the electric polarization at the perovskite grain boundaries of the photoelectric conversion layer can be stabilized by applying an external electric field to the photoelectric conversion layer using the first and second applied electrodes.

[0154] The photoelectric conversion module according to aspect 15 of this disclosure comprises a plurality of photoelectric conversion elements described in any one of aspects 1 to 14 above, and the plurality of integrated photoelectric conversion elements are sealed by a barrier layer.

[0155] According to the above configuration, the electric polarization at the perovskite crystal grain boundaries of the photoelectric conversion layer provided in the multiple photoelectric conversion elements integrated into the photoelectric conversion module is stabilized.

[0156] A photoelectric conversion system according to aspect 16 of the present disclosure comprises a photoelectric conversion element according to any one of aspects 1 to 14 above, an output control unit connected to the surface electrode and the back electrode for controlling the output of the current taken from the surface electrode and the back electrode, and an external electric field control unit connected to the first applied electrode and the second applied electrode for controlling the direction and intensity of the external electric field.

[0157] With the above configuration, the direction and intensity of the external electric field applied to the photoelectric conversion layer are controlled by the external electric field control unit, thereby stabilizing the electric polarization at the perovskite grain boundaries of the photoelectric conversion layer.

[0158] This disclosure is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of this disclosure. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment. [Explanation of symbols]

[0159] 1. Photoelectric conversion element 2 Photoelectric conversion layer 3 Surface electrode 4. Backside electrode 5 1st application electrode 6 Second application electrode 7. First Carrier Transport Layer 8. Second Carrier Transport Layer 9 Transparent substrate 10 Insulating layer 11. Photoelectric Conversion Module 12 Photoelectric Conversion System 13 Output Control Unit 14 External electric field control unit

Claims

1. A photoelectric conversion layer containing a perovskite compound, In order to extract the current generated by the photovoltaic power of the photoelectric conversion layer, a surface electrode located on the light incident side of the photoelectric conversion layer is provided, To extract the aforementioned current, a back electrode located on the opposite side of the surface electrode of the photoelectric conversion layer is provided, To apply an external electric field to the photoelectric conversion layer, a first application electrode is located on the opposite side of the surface electrode from the photoelectric conversion layer, A photoelectric conversion element comprising a second application electrode located on the opposite side of the first application electrode of the photoelectric conversion layer for applying the external electric field to the photoelectric conversion layer.

2. The photoelectric conversion element according to claim 1, wherein the second applied electrode is located on the opposite side of the back electrode from the photoelectric conversion layer.

3. A photoelectric conversion layer containing a perovskite compound, The surface electrode and the back electrode are arranged so as to sandwich the photoelectric conversion layer, A carrier transport layer is disposed between the surface electrode and the back electrode, A first applied electrode located on the opposite side of the surface electrode from the photoelectric conversion layer, A second application electrode located on the opposite side of the first application electrode of the photoelectric conversion layer, A photoelectric conversion element equipped with the following features.

4. The photoelectric conversion element according to claim 1 or 3, wherein the second applied electrode is shared with the back electrode.

5. A first carrier transport layer located between the surface electrode and the photoelectric conversion layer, A photoelectric conversion element according to any one of claims 1 to 3, further comprising a second carrier transport layer located between the back electrode and the photoelectric conversion layer.

6. The first carrier transport layer comprises an electron transport material and a hole blocking material, The photoelectric conversion element according to claim 5, wherein the second carrier transport layer comprises a hole transport material and an electron blocking material.

7. The first carrier transport layer comprises a hole transport material and an electron blocking material, The photoelectric conversion element according to claim 5, wherein the second carrier transport layer comprises an electron transport material and a hole blocking material.

8. A transparent substrate positioned between the surface electrode and the first applied electrode, The photoelectric conversion element according to any one of claims 1 to 3, further comprising an insulating layer located between the back electrode and the second applied electrode.

9. The photoelectric conversion element according to any one of claims 1 to 3, further comprising another photoelectric conversion layer located between the photoelectric conversion layer and the back electrode, or located between the back electrode and the second application electrode.

10. The photoelectric conversion element according to claim 9, wherein the other photoelectric conversion layer includes a Si-based photoelectric conversion element.

11. The photoelectric conversion element according to claim 9, wherein the other photoelectric conversion layer comprises a perovskite compound or a CIGS compound.

12. The other photoelectric conversion layer is located between the back electrode and the second application electrode. In order to extract other currents generated by the photovoltaic power of the other photoelectric conversion layer, another surface electrode located on the light incident side of the other photoelectric conversion layer is provided, The photoelectric conversion element according to claim 9, further comprising another back electrode located on the opposite side of the other surface electrode of the other photoelectric conversion layer in order to extract the other current.

13. The photoelectric conversion element according to any one of claims 1 to 3, wherein the photoelectric conversion layer further comprises insulating fine particles.

14. The photoelectric conversion element according to any one of claims 1 to 3, wherein the distance between the first applied electrode and the second applied electrode is 3 mm or less.

15. Multiple photoelectric conversion elements according to any one of claims 1 to 3 are integrated, A photoelectric conversion module in which the aforementioned integrated photoelectric conversion elements are sealed by a barrier layer.

16. A photoelectric conversion element according to any one of claims 1 to 3, An output control unit connected to the surface electrode and the back electrode for controlling the output of the current taken from the surface electrode and the back electrode, A photoelectric conversion system comprising an external electric field control unit connected to the first and second applied electrodes for controlling the direction and intensity of the external electric field.

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