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

Abstract

A photoelectric conversion element (10) comprises: a first electrode (11) and a second electrode (15); a photoelectric conversion layer (13) provided between the first electrode (11) and the second electrode (15); and a hole transport layer (14) provided between the first electrode (11) and the photoelectric conversion layer (13) or between the second electrode (15) and the photoelectric conversion layer (13). The hole transport layer (14) includes a hole-transporting molecular material and Cs atoms.

Description

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

[0001] The present disclosure relates to a photoelectric conversion element, a photoelectric conversion module, and a photoelectric conversion system that use a perovskite compound.

[0002] Typically, the hole transport layer of a photoelectric conversion element contains lithium bis(trifluoromethanesulfonyl)imide (hereinafter referred to as LiTFSI) and 4-tert-butylpyridine (hereinafter referred to as tBP) as doping materials (see, for example, Patent Document 1).

[0003] JP 2017-50426 A

[0004] In recent years, solar cells (perovskite solar cells) including a photoelectric conversion layer using a perovskite compound have been attracting attention. In a photoelectric conversion element of a perovskite solar cell, when LiTFSI is used as a doping material for the hole transport layer, Li in the hole transport layer is likely to diffuse into the photoelectric conversion layer (perovskite layer) due to voltage application and temperature rise caused by device operation, which can easily cause performance degradation. Alternatively, because LiTFSI is hygroscopic, moisture in the air may penetrate into the photoelectric conversion layer via LiTFSI, which can cause performance degradation. Furthermore, tBP corrodes the perovskite layer, which can easily cause performance degradation. Similar issues also arise in light-emitting devices including a light-emitting layer using a perovskite compound.

[0005] The present disclosure has been made in view of the above-mentioned problems, and aims to provide a photoelectric conversion element, a photoelectric conversion module, and a photoelectric conversion system that are less susceptible to deterioration of characteristics due to doping materials in the hole transport layer.

[0006] In order to solve the above problems, the following photoelectric conversion element, photoelectric conversion module, and photoelectric conversion system are provided.

[0007] (1) Photoelectric Conversion Element The photoelectric conversion element of the present disclosure comprises a first electrode and a second electrode, a photoelectric conversion layer provided between the first electrode and the second electrode, and a hole transport layer provided between the first electrode and the photoelectric conversion layer or between the second electrode and the photoelectric conversion layer, wherein the hole transport layer contains a hole transport molecular material and Cs atoms.

[0008] (2) Photoelectric Conversion Module The photoelectric conversion module of the present disclosure includes at least one photoelectric conversion element, and the photoelectric conversion element is the photoelectric conversion element described above.

[0009] (3) Photoelectric Conversion System A photoelectric conversion system according to the present disclosure includes the photoelectric conversion module described above and a control circuit.

[0010] The photoelectric conversion element, photoelectric conversion module, and photoelectric conversion system of the present disclosure can suppress deterioration of characteristics due to the doping material in the hole transport layer.

[0011] Fig. 4 is a schematic cross-sectional view of a photoelectric conversion element according to the present disclosure; Fig. 5 is a schematic cross-sectional view showing a modified example of the photoelectric conversion element; Fig. 6 is a plan view of a photoelectric conversion module according to the present disclosure; Fig. 7 is a cross-sectional view of the photoelectric conversion module shown in Fig. 3; Fig. 8 is a circuit diagram of the photoelectric conversion module shown in Fig. 3; Fig. 9 is a schematic view of a photoelectric conversion system according to the present disclosure; Fig. 10 is a schematic cross-sectional view of a light-emitting element according to the present disclosure.

[0012] First Embodiment Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Fig. 1 shows an embodiment of the present disclosure and is a schematic cross-sectional view of a photoelectric conversion element 10.

[0013] As shown in FIG. 1 , a photoelectric conversion element 10 is formed on a substrate 20 and includes a first electrode 11, an electron transport layer 12, a photoelectric conversion layer 13, a hole transport layer 14, and a second electrode 15. The first electrode 11, the electron transport layer 12, the photoelectric conversion layer 13, the hole transport layer 14, and the second electrode 15 are stacked in this order from the side closest to the substrate 20. The stacking order does not necessarily have to be this order (forward structure type), and the order of the electron transport layer 12 and the hole transport layer 14 may be reversed (inverse structure type). That is, the hole transport side may be on the bottom and the electron transport side may be on the top. In this disclosure, a forward structure type electron transport layer is described, but in the case of an inverse structure type, it may be replaced with a hole transport layer unless inconsistent.

[0014] The positions of the electron transport layer 12 and the hole transport layer 14 may be interchanged. The electron transport layer 12 is not essential for the photoelectric conversion element 10, and may be omitted.

[0015] The substrate 20 is a substrate on which the photoelectric conversion element 10 is provided. In the present disclosure, the substrate 20 is not included in the photoelectric conversion element 10, but it may be included in the photoelectric conversion element 10. The substrate 20 is also called a base or a substrate, and may be the same as or include these. The substrate 20 may be hard and highly rigid, or may be flexible and low in rigidity. The substrate 20 is preferably light-transmitting, and may be, for example, a resin film such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or polyimide, or glass. Note that light-transmitting means transmitting light, but does not exclude materials that reflect or absorb even a small amount of light. It is sufficient for the substrate to be provided on the light-receiving or light-emitting surface side of the element and to transmit light appropriately, and can be considered synonymous with being provided on the light-receiving or light-emitting surface side of the element. Therefore, being provided on at least the light-receiving surface side of the photoelectric conversion element 10 (or the light-emitting surface side of the light-emitting element 10A described below) can be considered light-transmitting.

[0016] The first electrode 11 is a conductive member. It is preferable to use a light-transmitting conductive material as the first electrode 11, and examples of transparent conductive materials that can be used include aluminum-doped zinc oxide (AZO), indium zinc oxide (IZO), gallium-doped zinc oxide (GZO), tin oxide (SnO), fluorine-doped tin oxide (FTO), and indium tin oxide (ITO). The first electrode 11 may be formed by a known method such as sputtering or vapor deposition, and the thickness may be, for example, 30 nm to 1000 nm.

[0017] The electron transport layer 12 is a layer capable of transporting electrons. As long as the photoelectric conversion element 10 (or the light-emitting element 10A described later) is functioning, it is self-evident that the layer disposed on the negative electrode side of the element has an electron transport function, and can therefore be used as the electron transport layer. The negative electrode side can also be referred to as the electron transport side.

[0018] The electron transport layer 12 can be made of tin oxide, titanium oxide, zinc oxide, indium oxide, or a mixture or compound of two or more of these. The electron transport layer 12 can be formed by a known method such as spin coating or sputtering, and the film thickness can be, for example, 10 nm to 200 nm. The electron transport layer 12 may also be capable of inhibiting hole transport (hole blocking). The electron transport layer 12 may also be accompanied by a separate hole blocking layer. Alternatively, the electron transport layer 12 may be omitted, and a hole blocking layer may be present instead. The electron transport layer 12 and the hole blocking layer may be the same. As with the electron transport layer 12, the hole blocking layer does not need to be confirmed as long as the device functions.

[0019] The photoelectric conversion layer 13 is a layer capable of absorbing light and generating electrons and holes. When used as a light-emitting element, the layer is capable of recombining electrons and holes to emit light. The photoelectric conversion layer 13 includes a light-absorbing portion containing a perovskite compound or the like that is capable of absorbing light and generating electrons and holes. When used as a light-emitting element, the photoelectric conversion layer includes a light-emitting portion containing a perovskite compound or the like that is capable of recombining electrons and holes to emit light. The photoelectric conversion layer 13 may also include an electron transport layer, a hole transport layer, or an insulating layer. The electron transport layer, hole transport layer, or insulating layer included in the photoelectric conversion layer 13 is preferably made of a porous material.

[0020] The photoelectric conversion layer 13 may be, for example, a perovskite-type compound containing a halogen. Photoelectric conversion layers 13 containing perovskite compounds typically used in solar cells contain at least one element selected from the group consisting of Cs, FA (formamidinium, CH(NH)), and MA (methylammonium, CHNH), at least one element selected from the group consisting of Pb and Sn, and at least one element selected from the group consisting of I, Br, and Cl. However, the constituent elements described in this embodiment, including the above-mentioned FA and MA, may be ionized or not. The photoelectric conversion layer 13 may be formed by a known film formation method such as spin coating, die coating, or inkjet printing, and the film thickness may be, for example, 100 nm to 1000 nm. Unless otherwise specified, the term "layer" does not specify a thickness or width, and may include patterned or island-shaped layers or layers having portions of different thicknesses. The layer preferably has a substantially constant thickness.

[0021] The perovskite compound is composed of a compound represented by the general formula: ABX3 (1). However, while the composition ratio of each element is preferably 1:1:3, it does not necessarily have to be 1:1:3. The content of each element may vary as appropriate, and each constituent element does not necessarily have to be of a single type. As long as the photoelectric conversion element 10 has a photoelectric conversion function, there is a degree of freedom in the configuration as described above. In general formula (1), A is an organic molecule (including an organic group or an organic cation, the same applies in this disclosure) or an inorganic atom (including an inorganic cation, the same applies in this disclosure), or a combination thereof; B is a metal atom (including a metal cation, the same applies in this disclosure); and X is a halogen atom (including a halogen anion, the same applies in this disclosure). In general formula (1), the three Xs may be the same or different from each other. When contained in the photoelectric conversion layer 13, a perovskite compound can absorb light and convert it into electricity, and this fact should also be taken into consideration. That is, a perovskite compound can be confirmed by, for example, detecting organic molecules, metal atoms, and halogen atoms. Furthermore, a perovskite compound can be confirmed by detecting elements corresponding to A, B, and X, so long as the photoelectric conversion element 10 has a photoelectric conversion function. For example, molecules containing carbon, nitrogen, and hydrogen are suitable as organic molecules, and therefore, carbon, nitrogen, hydrogen, metal elements, and halogen elements can be detected. Alternatively, a perovskite compound can be confirmed by detecting A, B, and X, for example, detecting inorganic atoms, metal atoms, and halogen atoms. Furthermore, a perovskite compound can be confirmed by detecting elements corresponding to A, B, and X, so long as the photoelectric conversion element 10 has a photoelectric conversion function. For example, cesium or rubidium is preferred as the inorganic atom, and therefore, it is sufficient to detect cesium or rubidium, a metal element (preferably lead or tin), and a halogen. Furthermore, since it is a natural consequence that the photoelectric conversion element 10 has a crystalline structure in order to have a photoelectric conversion function, it is not necessary to confirm that the compound is a perovskite compound. This does not exclude the photoelectric conversion layer 13 from including compounds other than perovskite compounds.

[0022] The light absorbing layer may contain an organic-inorganic hybrid compound. An organic-inorganic hybrid compound refers to a compound containing both inorganic and organic elements. Perovskite compounds are included in organic-inorganic hybrid compounds. Organic typically refers to a material composed of multiple carbon elements. Carbon materials such as graphite, graphene, carbon nanowires, carbon nanofibers, carbon nanotubes, and carbon and carbon black that function as electrodes are not considered to be organic. In other words, organic refers to materials that contain multiple carbon elements, excluding carbon materials such as graphite. Inorganic refers to materials that are not organic.

[0023] In general formula (1), examples of the organic molecule represented by A include alkylamine, alkylammonium, and nitrogen-containing heterocyclic compounds. In the perovskite compound (1), the organic molecule represented by A may be only one type of organic molecule, or may be two or more types of organic molecules.

[0024] 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.

[0025] The alkylammonium is an ionized product of the alkylamine. Examples of the alkylammonium 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.

[0026] Examples of the nitrogen-containing heterocyclic compound include imidazole, azole, pyrrole, aziridine, azirine, azetidine, azeto, azole, imidazoline, and carbazole. The nitrogen-containing heterocyclic compound may be an ionized compound. Phenethylammonium is preferred as the ionized nitrogen-containing heterocyclic compound.

[0027] In general formula (1), 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.

[0028] In general formula (1), examples of the metal atom 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, the metal atom represented by B may be only one type of metal atom, or may be two or more types of metal atoms. From the viewpoint of improving the light absorption properties and charge generation properties of the perovskite compound, the metal atom represented by B is preferably a lead atom or a tin atom. From the viewpoint of reducing lead, a tin atom is preferred.

[0029] In addition, in general formula (1), examples of halogen atoms represented by X include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms, and examples of chalcogen atoms include oxygen atoms, sulfur atoms, selenium atoms, and tellurium atoms. In the perovskite compound, the halogen atoms or chalcogen atoms represented by X may be one type or two or more types. As the halogen atom represented by X, an iodine atom is preferred from the viewpoint of enabling the perovskite compound to utilize light in a wide wavelength range. Specifically, of the three Xs, it is preferred that at least one X represents an iodine atom, and it is more preferred that all three Xs represent iodine atoms.

[0030] In the perovskite compound contained in the light absorption layer, in general formula (1), A is preferably any one or more selected from the group consisting of cesium, rubidium, methylammonium, and formamidinium. In addition, in general formula (1), B is preferably any one or more selected from the group consisting of lead and tin. In addition, in general formula (1), C is preferably any one or more selected from the group consisting of iodine, bromine, and chlorine.

[0031] The hole transport layer 14 is a layer capable of transporting holes. Materials for the hole transport layer 14 will be described later. It is self-evident that, as long as the photoelectric conversion element 10 (or light-emitting element 10A) is functioning, any layer disposed on the positive electrode side of the element has hole transport function, and this can be used as the hole transport layer. The hole transport layer 14 may also be capable of inhibiting electron transport (electron blocking). The hole transport layer 14 may also be accompanied by a separate electron blocking layer. Alternatively, the hole transport layer 14 may be omitted, and an electron blocking layer may be present instead. The hole transport layer 14 and the electron blocking layer may refer to a common layer. As with the hole transport layer 14, the electron blocking layer is also disposed on the positive electrode side of the element, and confirmation is not required as long as the element is functioning. The positive electrode side may also be referred to as the hole transport side. The hole transport layer 14 may be formed by a known film formation method such as spin coating, die coating, or ink jetting, and the thickness may be, for example, 40 nm to 600 nm.

[0032] The second electrode 15 preferably contains a metal or alloy containing at least one of Au, Ag, Cu, and Al. Alternatively, a transparent conductive material such as ITO, ZnO, FTO, SnO2, or IZO may be used as the second electrode 15. The second electrode 15 may be formed by a known film formation method such as vacuum deposition or sputtering, and the film thickness may be, for example, 50 nm to 300 nm.

[0033] The hole transport layer 14 in the photoelectric conversion element 10 of the present disclosure will be described in detail below.

[0034] The hole transport layer 14 is formed by adding a doping material to a hole transport molecular material. Examples of hole transport molecular materials that can be used include spiro-OMeTAD (2,2',7,7'-Tetrakis(N,N-di-p-methoxyphenylamino)-9,9'-spirobifluorene), PTAA (Poly[bis(4-phenyl)(2,4,6-triMethylphenyl)amine]), P3HT (Poly(3-hexylthiophene-2,5-diyl)), poly-TPD (Poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine]), and PVK (polyvinylcarbazole). The hole transport layer 14 can be formed by dissolving a doping material (described later) in a solvent to prepare a precursor solution, and then forming a film using a known film formation method.

[0035] In the photoelectric conversion element 10 of the present disclosure, the hole transport layer 14 does not need to use LiTFSI and tBP as doping materials. Instead, the hole transport layer 14 contains Cs atoms as a doping material. In the present disclosure, Cs atoms include Cs ions. In the hole transport layer 14, the molar ratio of Cs atoms to hole transport molecules is preferably 0.01 or more and 1.00 or less. Furthermore, it is most preferable that LiTFSI and tBP are not contained at all as doping materials, but this does not mean that they are completely prohibited, and their inclusion as appropriate is permitted.

[0036] Cs has a larger atomic radius and ionic radius than Li, and therefore is less likely to diffuse into the perovskite layer (i.e., photoelectric conversion layer 13). As a result, the hole transport layer 14 using Cs atoms or Cs ions as the doping material makes it less likely for the doping material to diffuse into the photoelectric conversion layer 13, and deterioration of the characteristics of the photoelectric conversion element 10 can be suppressed.

[0037] The hole transport layer 14 may also contain TFSI molecules or ions. In this case, the hole transport layer 14 can use CsTFSI as a doping material, which makes it easier to obtain an effective doping effect.

[0038] Furthermore, the hole transport layer 14 preferably contains a crown ether (crown ether molecule). Dibenzo-21-crown-7 is a suitable crown ether, and the hole transport layer 14 preferably contains Dibenzo-21-crown-7 molecules. In the hole transport layer 14, the molar ratio of crown ether molecules to Cs atoms is preferably 0.9 or more and 1.1 or less.

[0039] For example, when CsTFSI and Dibenzo-21-crown-7 are used as doping materials in the hole transport layer 14, Cs atoms or Cs ions are incorporated into Dibenzo-21-crown-7 to form a complex shown in the following formula: Furthermore, CsTFSI that has lost its Cs atom becomes TFSI molecules or ions and exists in the hole transport layer 14, contributing to an increase in the hole density in the hole transport layer 14.

[0040]

[0041] In this case, by incorporating Cs atoms or Cs ions into the crown ether, it is possible to more effectively prevent Cs from diffusing into layers (e.g., the photoelectric conversion layer 13) other than the hole transport layer 14. Furthermore, the crown ether can prevent the Cs atoms or Cs ions from coming into direct contact with the hole transport molecule, thereby improving the hole transport ability of the hole transport molecule.

[0042] Second Embodiment In this embodiment, a description will be given of a preferred example of the photoelectric conversion layer 13. In this embodiment, the same configuration as in the first embodiment can be used except for the points described below.

[0043] In this embodiment, the photoelectric conversion layer 13 contains Cs. When the photoelectric conversion layer 13 contains Cs in this manner, Cs is contained in both the photoelectric conversion layer 13 and the hole transport layer 14 in the photoelectric conversion element 10. In this case, the Cs in the photoelectric conversion layer 13 acts to suppress the diffusion of Cs from the hole transport layer 14 to the photoelectric conversion layer 13. As a result, composition changes in the photoelectric conversion layer 13 are suppressed, and deterioration of the characteristics of the photoelectric conversion element 10 can be more effectively suppressed.

[0044] In order to suppress the diffusion of Cs from the hole transport layer 14 to the photoelectric conversion layer 13 by the above-mentioned action, it is preferable that the Cs atom number density is higher in a region of the photoelectric conversion layer 13 that is closer to the hole transport layer 14. Therefore, in the photoelectric conversion layer 13, the Cs atom number density in a region closer to the hole transport layer 14 may be higher than the Cs atom number density in a region farther from the hole transport layer 14. For example, as shown in FIG. 2 , when the hole transport layer 14 is divided into two regions 14a and 14b at the center in the thickness direction, the Cs atom number density (average Cs atom number density) in the region 14a closer to the hole transport layer 14 may be higher than the Cs atom number density (average Cs atom number density) in the region 14b farther from the hole transport layer 14. Alternatively, when comparing one point in region 14a with one point in region 14b, the Cs atom number density in region 14a may be made larger than the Cs atom number density in region 14b (for example, a point in region 14a and a point in region 14b can be measured and compared on a cross section of the device by Auger electron spectroscopy (or energy dispersive X-ray analysis). In this case, the Cs atom number density in region 14a is preferably 1.2 times or more, and more preferably 10 times or more, the Cs atom number density in region 14b.

[0045] Third Embodiment In this embodiment, a photovoltaic conversion module and a photovoltaic conversion system according to the present disclosure will be described. Fig. 3 is a plan view of a photovoltaic conversion module 100 according to the present disclosure. Fig. 4 is a cross-sectional view of the photovoltaic conversion module 100 (cross-sectional view taken along line IV-IV in Fig. 3).

[0046] The photoelectric conversion module 100 includes a plurality of photoelectric conversion elements 10 of any one of the first and second embodiments described above, and the plurality of photoelectric conversion elements 10 are connected in series. However, in the photoelectric conversion module of the present disclosure, the number of photoelectric conversion elements 10 is not particularly limited, and it is sufficient that at least one photoelectric conversion element 10 is included. Furthermore, when a plurality of photoelectric conversion elements 10 are included, the element connection is not limited to a series connection, and may be a parallel connection, or a combination of a series connection and a parallel connection.

[0047] As shown in Fig. 3, the photoelectric conversion module 100 is patterned by several cuts and has regions P1, P2, and P3 corresponding to these cut locations. In Fig. 3, the second electrode 15 and the first electrode 11 (or the electron transport layer 12) of the photoelectric conversion element 10 are present on the surface. For example, wet etching, dry etching, laser scribing, or mechanical scribing can be used to pattern the regions P1 to P3.

[0048] As shown in Figure 4, the notch in region P1 is formed by etching away the first electrode 11, and separates the first electrodes 11 of two adjacent photoelectric conversion elements 10 (for example, photoelectric conversion elements 10a and 10b in Figure 4).

[0049] The notch in region P2 is formed by etching away the electron transport layer 12, the photoelectric conversion layer 13, and the hole transport layer 14, and is provided to electrically connect two adjacent photoelectric conversion elements 10 (e.g., photoelectric conversion elements 10a and 10b in FIG. 8 ). That is, in region P2, the material of the second electrode 15 is filled into the formed notch, thereby connecting the second electrode 15 of one photoelectric conversion element 10 (e.g., photoelectric conversion element 10a) to the first electrode 11 of the other photoelectric conversion element 10 (e.g., photoelectric conversion element 10b).

[0050] The notch in region P3 is formed by patterning the photoelectric conversion layer 13, the hole transport layer 14, and the second electrode 15, and is provided to separate the second electrodes 15 of two adjacent photoelectric conversion elements 10 (e.g., photoelectric conversion elements 10a and 10b in FIG. 4 ). Note that in region P3 in FIG. 4 , the notch is formed by etching away the photoelectric conversion layer 13, exposing the electron transport layer 12 at the surface of region P3. However, in region P3, it is sufficient that at least the second electrode 15 is removed, and it is more preferable that the hole transport layer 14 is also removed. However, the photoelectric conversion layer 15 does not necessarily have to be removed. In other words, a portion of the photoelectric conversion layer 13 may remain. In this case, the photoelectric conversion layer 13 is exposed at the surface of region P3. Alternatively, at least a portion of the hole transport layer 14 may be exposed without removing at least a portion of the hole transport layer 14. Alternatively, the electron transport layer 12 may also be removed to expose at least a portion of the first electrode 11 .

[0051] In the photoelectric conversion module 100, the region between region P3 and region P1 but not including region P2 is the formation region for the photoelectric conversion elements 10. The region between region P3 and region P1 but including region P2 is a connection region for electrically connecting two adjacent photoelectric conversion elements 10.

[0052] In this way, the photoelectric conversion module 100 is configured such that the photoelectric conversion elements 10 are isolated by the regions P1 and P3, and two adjacent photoelectric conversion elements 10 are electrically connected by the region P2. As a result, the photoelectric conversion module 100 includes a plurality of photoelectric conversion elements 10 connected in series, as shown in the circuit diagram of FIG.

[0053] FIG. 6 is a schematic diagram of a photovoltaic conversion system 1000 according to the present disclosure. As shown in FIG. 6 , the photovoltaic conversion system 1000 includes the above-described photovoltaic conversion module 100, a power conditioner 101, a distribution board 102, a power meter 103, a storage battery 104, and an electrical device 105. The photovoltaic conversion system 1000 illustrated in FIG. 10 includes one each of the photovoltaic conversion module 100, the power conditioner 101 as an example of a control circuit, the distribution board 102, the power meter 103, the storage battery 104, and the electrical device 105, but multiples of each may also be provided. That is, the photovoltaic conversion system 1000 includes the photovoltaic conversion module 100 and a control circuit. Note that the control circuit may be any circuit capable of controlling the current or voltage output from the photovoltaic conversion module 100.

[0054] The power conditioner 101 controls the current and voltage so that the power output from the photovoltaic conversion module 100 is optimized, and performs the desired power distribution while monitoring the output power of the photovoltaic conversion module 100 and the charge amount of the storage battery 104, and outputs power to the storage battery 104 and the distribution board 102. At this time, the power conditioner 101 outputs DC power to the storage battery 104 and AC power to the distribution board 102. In other words, the power conditioner 101 has the function of converting DC power into AC power.

[0055] The distribution board 102 supplies the AC power received from the power conditioner 101 to the electrical equipment 105 and the power meter 103 in a desired distribution while monitoring the output power of the power conditioner 101 and the power consumption of the electrical equipment 105 .

[0056] The power meter 103 measures the power supplied from the distribution board 102 and supplies it to the commercial power system.

[0057] The electrical device 105 may be connected to the power conditioner 101 instead of being connected to the distribution board 102. In this case, the power conditioner 101 performs the desired power distribution while monitoring the output power of the photovoltaic conversion module 100, the charge level of the storage battery 104, and the power consumption of the electrical device 105, and supplies AC power to the distribution board 102, DC power to the storage battery 104, and AC power to the electrical device 105. If the electrical device 105 is for DC power, DC power may be supplied.

[0058] Fourth Embodiment In the first and second embodiments, the photoelectric conversion element 10 according to the present disclosure has been described, but in this embodiment, a case will be described in which the photoelectric conversion element 10 according to the present disclosure functions as a light-emitting element 10A. Fig. 7 is a schematic cross-sectional view of the light-emitting element 10A.

[0059] 7 , the light-emitting element 10A has a configuration substantially similar to that of the photoelectric conversion element 10, but includes a light-emitting layer 13A instead of the photoelectric conversion layer 13 of the photoelectric conversion element 10. The first electrode 11, the electron transport layer 12, the hole transport layer 14, and the second electrode 15 of the light-emitting element 10A can have the same configuration as those of the photoelectric conversion element 10. The substrate 20 can also be used in the same manner as that of the photoelectric conversion element 10. The light-emitting element 10A is an element in which a current is passed through the light-emitting layer 13A via the first electrode 11 and the second electrode 15, causing the light-emitting layer 13A to emit light.

[0060] In the light-emitting element 10A, for example, a perovskite semiconductor containing a halogen is used in the light-emitting layer 13A. That is, while the photoelectric conversion layer 13 in the photoelectric conversion element 10 is a perovskite layer, the light-emitting layer 13A in the light-emitting element 10A is a perovskite layer. Note that the perovskite semiconductor used as the light-emitting layer can be made of the same material and formed by the same method as in the photoelectric conversion element 10, but is not limited to this.

[0061] In a light-emitting element having a perovskite layer, when LiTFSI or tBP is used as a doping material for the hole transport layer, there is a problem of deterioration in the characteristics of the perovskite layer, as in the case of a photoelectric conversion element. Therefore, in the light-emitting element 10A of this embodiment, by using the hole transport layer 14 described in the first and second embodiments, deterioration in the characteristics of the light-emitting layer 13A can be suppressed.

[0062] In addition, the photoelectric conversion module 100 and photoelectric conversion system 1000 described in the third embodiment can also be modified into a photoelectric conversion module and photoelectric conversion system in which the direction of current flow is reversed to cause the photoelectric conversion element 10 to function as a light-emitting element 10A.

[0063] The embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present disclosure should not be interpreted solely by the above-described embodiments, but should be determined based on the claims.

[0064] This international application claims priority based on Japanese Patent Application No. 2024-029690, filed on February 29, 2024, the entire contents of which are incorporated herein by reference.

[0065] REFERENCE SIGNS LIST 10 Photoelectric conversion element 10A Light-emitting element 20 Substrate 11 First electrode 12 Electron transport layer 13 Photoelectric conversion layer 13A Light-emitting layer 14 Hole transport layer 15 Second electrode 100 Photoelectric conversion module 101 Power conditioner (control circuit) 1000 Photoelectric conversion system

Claims

1. A photoelectric conversion element comprising: a first electrode and a second electrode; a photoelectric conversion layer provided between the first electrode and the second electrode; and a hole transport layer provided between the first electrode and the photoelectric conversion layer or between the second electrode and the photoelectric conversion layer, wherein the hole transport layer contains a hole transporting molecular material and Cs atoms.

2. A photoelectric conversion element according to claim 1, wherein the molar ratio of Cs atoms to hole transport molecules in said hole transport layer is 0.01 or more and 1.00 or less.

3. A photoelectric conversion element according to claim 1 or 2, wherein the hole transporting molecular material is any one of spiro-OMeTAD, PTAA, P3HT, poly-TPD and PVK.

4. A photoelectric conversion element according to any one of claims 1 to 3, characterized in that the hole transport layer further contains crown ether molecules.

5. The photoelectric conversion element according to claim 4, wherein the crown ether molecule is a Dibenzo-21-crown-7 molecule.

6. A photoelectric conversion element according to claim 4, wherein the molar ratio of said crown ether molecules to said Cs atoms in said hole transport layer is 0.9 or more and 1.1 or less.

7. A photoelectric conversion element according to any one of claims 1 to 6, characterized in that the photoelectric conversion layer contains one or more elements selected from the group consisting of Cs, FA, and MA, one or more elements selected from the group consisting of Pb and Sn, and one or more elements selected from the group consisting of I, Br, and Cl.

8. The photoelectric conversion element according to claim 7, wherein the photoelectric conversion layer contains Cs.

9. A photoelectric conversion element according to claim 8, characterized in that in the photoelectric conversion layer, the Cs atom number density in a region close to the hole transport layer is greater than the Cs atom number density in a region far from the hole transport layer.

10. A photoelectric conversion element according to claim 9, characterized in that the Cs atom number density in the region close to the hole transport layer is 1.2 times or more the Cs atom number density in the region far from the hole transport layer.

11. A photoelectric conversion element according to claim 9, characterized in that the Cs atom number density in the region close to the hole transport layer is 10 times or more the Cs atom number density in the region far from the hole transport layer.

12. A photoelectric conversion module having at least one photoelectric conversion element, the photoelectric conversion element being the photoelectric conversion element according to any one of claims 1 to 11.

13. A photoelectric conversion system comprising the photoelectric conversion module according to claim 12 and a control circuit.

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