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

Abstract

A photoelectric conversion element (10) according to the present disclosure is characterized by being provided with a first multilayer body (LS1) which includes: a first electrode (2); an electron transport layer (3) that is provided on the first electrode (2); a photoelectric conversion layer (4) that is provided on the electron transport layer (3); a hole transport layer (5) that is provided on the photoelectric conversion layer (4); a first buffer layer (6a) that is provided on the hole transport layer (5); a second buffer layer (6b) that is provided on the first buffer layer (6a); and a second electrode (7) that is provided on the second buffer layer (6b). The photoelectric conversion element (10) is also characterized in that: the first buffer layer (6a) contains a metal oxide; and the second buffer layer (6b) contains a nitride that contains any one or more elements selected from the group consisting of Ti, Ta, Zr, and Hf, or a metal or alloy that contains any one or more elements selected from the group consisting of Ti and Ta.

Description

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

[0001] This disclosure relates to a photoelectric conversion element, a photoelectric conversion module, and a photoelectric conversion system. This application claims priority to Japanese Patent Application No. 2023-141338, filed on August 31, 2023, the contents of which are incorporated herein by reference.

[0002] Photoelectric conversion elements have been disclosed in the past.

[0003] For example, Patent Document 1 discloses the following: A photoelectric conversion element includes a pair of electrodes composed of a first electrode 101 and a second electrode 107, an active layer 103 containing a perovskite compound between the pair of electrodes, and a second electrode. A first buffer layer 105 and a second buffer layer 106 are provided between the active layer and the second electrode. The second buffer layer 106 contacts the active layer 103, the first buffer layer 105, and the second electrode 107 (through pinholes in the first buffer layer 105, etc.). The first buffer layer 105 is a hole transport layer, and the second buffer layer 106 is a metal oxide (e.g., molybdenum oxide, vanadium oxide, tungsten oxide). The provision of the second buffer layer 106 reduces leakage current due to pinholes and coating defects in the first buffer layer 105. Furthermore, the reaction between halogens contained in the active layer 103 and the electrode material is suppressed.

[0004] Japanese Patent Application Laid-Open No. 2021-77788

[0005] However, although metal materials such as Au and Ag are generally used for the second electrode 107, these metal materials have poor adhesion to the second buffer layer made of a metal oxide, making it difficult to obtain good device characteristics. Furthermore, when a voltage is applied between the electrodes, Au, Ag, etc. tend to form filaments that penetrate the second buffer layer (molybdenum oxide, vanadium oxide, tungsten oxide) and further penetrate the hole transport layer (second buffer layer), resulting in an increase in leakage current and a deterioration in device characteristics.

[0006] An object of one embodiment of the present disclosure is to provide a photoelectric conversion element, a photoelectric conversion module, or a photoelectric conversion system that has improved performance, such as photoelectric conversion efficiency, compared to conventional devices.

[0007] A photoelectric conversion element according to one aspect of the present disclosure comprises a first stack including a first electrode, an electron transport layer provided on the first electrode, a photoelectric conversion layer provided on the electron transport layer, a hole transport layer provided on the photoelectric conversion layer, a first buffer layer provided on the hole transport layer, a second buffer layer provided on the first buffer layer, and a second electrode provided on the second buffer layer, wherein the first buffer layer contains a metal oxide, and the second buffer layer contains a nitride containing one or more elements selected from the group consisting of Ti, Ta, Zr, and Hf, or a metal or alloy containing one or more elements selected from the group consisting of Ti, Ta, Ti, and Ta.

[0008] A photoelectric conversion module according to another aspect of the present disclosure includes the photoelectric conversion element described above.

[0009] A photoelectric conversion system according to another aspect of the present disclosure includes the photoelectric conversion module described above and a control circuit.

[0010] According to one aspect of the present disclosure, it is possible to provide a photoelectric conversion element, a photoelectric conversion module, or a photoelectric conversion system with improved performance.

[0011] FIG. 1 is a cross-sectional view of a photoelectric conversion element according to the first embodiment. FIG. 2 is a cross-sectional view of a photoelectric conversion element according to the second embodiment. FIG. 3 is a cross-sectional view of a photoelectric conversion element according to the third embodiment. FIG. 4 is a cross-sectional view of a photoelectric conversion element according to the fourth embodiment. FIG. 5 is a plan view of a photoelectric conversion module according to the first embodiment. FIG. 6 is a cross-sectional view of the photoelectric conversion module shown in FIG. 5 taken along line VI-VI. FIG. 7 is a cross-sectional view of a modified example of the photoelectric conversion module according to the first embodiment. FIG. 8 is a cross-sectional view of a modified example of the photoelectric conversion module according to the first embodiment. FIG. 9 is a cross-sectional view of a photoelectric conversion module according to the second embodiment. FIG. 10 is a cross-sectional view of a modified example of the photoelectric conversion module according to the second embodiment. FIG. 11 is a cross-sectional view of a modified example of the photoelectric conversion module according to the second embodiment. FIG. 12 is a cross-sectional view of a modified example of the photoelectric conversion module according to the second embodiment. FIG. 13 is a cross-sectional view of a photoelectric conversion module according to the third embodiment. FIG. 14 is a cross-sectional view of a modified example of the photoelectric conversion module according to the third embodiment. FIG. 15 is a cross-sectional view of a modified example of the photoelectric conversion module according to the third embodiment. Fig. 16 is a cross-sectional view of a modified example of the photovoltaic conversion module according to the third embodiment. Fig. 17 is a cross-sectional view of a modified example of the photovoltaic conversion module according to the third embodiment. Fig. 18 is a cross-sectional view of a modified example of the photovoltaic conversion module according to the third embodiment. Fig. 19 is a cross-sectional view of a modified example of the photovoltaic conversion module according to the third embodiment. Fig. 20 is a cross-sectional view of a modified example of the photovoltaic conversion module according to the third embodiment. Fig. 21 is a schematic view of a photovoltaic conversion system according to the present disclosure.

[0012] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. Note that the present embodiments described below do not unnecessarily limit the content of the present disclosure as defined in the claims, and are not limited as long as there are no contradictions. Not all of the configurations described in the present embodiments are necessarily essential to the solution of the present disclosure. Furthermore, the light incident side (also referred to as the light receiving surface side) is expressed as the lower side (-Z direction) and the side opposite the light incident side as the upper side (+Z direction), but this is for convenience and does not affect the installation orientation or recommended installation orientation. Furthermore, as long as there are no contradictions, the above description can be understood even if the top and bottom are reversed. In other words, the present description is valid even if the light incident side and the side opposite the light incident side are reversed as long as there are no contradictions.

[0013] 1. Photoelectric Conversion Element 1-1. First Embodiment Fig. 1 is a cross-sectional view of a photoelectric conversion element 10 according to the first embodiment. As shown in Fig. 1, the photoelectric conversion element 10 according to the first embodiment includes a first stacked body LS1 and a base body 1. The first stacked body LS1 also includes a first electrode 2, an electron transport layer 3 provided on the first electrode 2, a photoelectric conversion layer 4 provided on the electron transport layer 3, a hole transport layer provided on the photoelectric conversion layer 4, a first buffer layer 6a provided on the hole transport layer, a second buffer layer 6b provided on the first buffer layer 6a, and a second electrode 7 provided on the second buffer layer 6b.

[0014] Each component will be described below.

[0015] [Base] The base 1 is the base of the photoelectric conversion element 10 and is the same as or includes the substrate or base material. In this embodiment, the base 1 is made of a transparent material. However, the side opposite the base of the photoelectric conversion element 10 may be made of a transparent material, or even both sides may be made of a transparent material. The base 1 is preferably a transparent base. The base 1 is disposed on the light-receiving side of the photoelectric conversion element 10 (also referred to as the light-receiving side, including the portion where light is incident, as in the present disclosure). The base 1 is also connected to the first electrode 2. Note that "connected" means being in direct physical contact. Furthermore, "transparent" or "light-transmitting" refers to transmitting light, but does not exclude materials that reflect or absorb even a small amount of light. It is sufficient for the base 1 to be disposed on the light-receiving side of the solar cell and appropriately transmit light. This can be considered synonymous with being disposed on the light-receiving side of the photoelectric conversion element. Therefore, being disposed at least on the light-receiving side of the photoelectric conversion element can be considered transparent. That is, the transparent substrate means a substrate provided on the light incident surface side of the photoelectric conversion element.

[0016] The material of the substrate 1 can be, for example, plastics such as PET and polyimide, glass, etc. By using a flexible substrate, the solar cell itself can be made flexible.

[0017] When the material of the base 1 is a transparent resin such as an organic film, the photoelectric conversion element 10 may have a barrier layer (not shown) on the base 1. This can prevent moisture and the like from penetrating into the photoelectric conversion layer 4. The barrier layer may be provided, for example, between the base 1 and the first electrode 2.

[0018] The thickness of the substrate 1 may be about 50 μm to 5000 μm.

[0019] [First Electrode] The first electrode 2 is a conductive member. For example, a transparent conductive film is used. The first electrode 2 is a conductive film on the light-receiving surface side of the photoelectric conversion element 10. Examples of materials constituting the first electrode 2 include transparent conductive materials (particularly, transparent conductive oxides (TCO)) and non-transparent conductive materials. Examples of transparent conductive materials include indium tin oxide (ITO), tin oxide (SnO ２Examples of suitable conductive materials include fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), indium zinc oxide (IZO), and gallium-doped zinc oxide (GZO). The film may be formed by a known method. For example, sputtering, CVD, or vapor deposition may be used. The film thickness of the first electrode 2 may be, for example, 30 nm to 1000 nm. A transparent conductive material refers to a material that, even if its physical properties are non-transparent, can be transparent depending on the thickness of the material and can therefore be used as a conductive film on the light-receiving surface side of a photoelectric conversion element. The term "film" does not specify thickness or width, and includes patterned or island-shaped films and films with portions of different thicknesses. A film preferably has a substantially constant thickness. Unless otherwise specified, the terms "approximately" and "approximately" mean that variations within the range of manufacturing error are allowed, and preferably indicate a variation of plus or minus 15% of the numerical value. In this disclosure, unless otherwise specified, thickness, width, etc. are confirmed by cross-sectional observation. For example, when observing using an SEM, it is sufficient to observe a single 400 nm-wide cross-sectional SEM image, and thickness, width, etc., within that range; it is not necessary to confirm all cross sections. In other words, a "substantially constant thickness" can be said to be a substantially constant thickness if the thickness in a single 400 nm-wide cross-sectional SEM image is within a range of plus or minus 15% of the average thickness. Note that the transparent conductive film does not necessarily have to be transparent. In other words, the photoelectric conversion function is ensured as long as there is even a partial transparent portion in the photoelectric conversion element, and the conductive film does not necessarily have to be transparent.

[0020] The first electrode 2 is provided on the substrate 1 and is electrically connected to the electron transport layer 3 .

[0021] [Electron Transport Layer] The electron transport layer 3 has the function of transporting electrons generated in the photoelectric conversion layer 4. Here, for example, it transports electrons generated in the photoelectric conversion layer 4 to the first electrode 2. Furthermore, the electron transport layer 3 preferably has the function of blocking holes generated in the photoelectric conversion layer 4. The electron transport layer 3 naturally has this function as long as it is disposed between the first electrode 2 and the photoelectric conversion layer 4 of the photoelectric conversion element 10, and there is no need to confirm this function as long as the photoelectric conversion element 10 functions when disposed between the first electrode 2 and the photoelectric conversion layer 4. The electron transport layer 3 preferably contains a material that easily transports electrons generated in the photoelectric conversion layer 4 to the first electrode 2. Note that a hole blocking layer may be used instead of the electron transport layer.

[0022] The electron transport layer 3 may be made of, for example, tin oxide, titanium oxide, zinc oxide, or the like. The layer thickness may be, for example, but not limited to, 10 nm to 200 nm. The layer may be formed by a known method. For example, sputtering, die coating, screen printing, or the like may be used.

[0023] [Photoelectric Conversion Layer] The photoelectric conversion layer 4 is a layer that absorbs light and generates electrons and holes. For example, a perovskite compound can be used. The photoelectric conversion layer 4 may be formed by a known film formation method such as spin coating, die coating, or inkjet printing. The thickness of the photoelectric conversion layer 4 may be, for example, 100 nm to 1000 nm.

[0024] The perovskite compound contained in the photoelectric conversion layer 4 is composed of a compound represented by the general formula: ABX3 (1). 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 a single type. As long as the photoelectric conversion element has a photoelectric conversion function, the perovskite compound used will exhibit the photoelectric conversion function. Therefore, even if there is a degree of freedom in the composition as described above regarding the composition ratio and the type of constituent elements, that function can be exhibited. In general formula (1), A is an organic molecule (including an organic group or an organic cation, as defined in the present disclosure) or an inorganic atom or molecule (including an inorganic group or an inorganic cation, as defined in the present disclosure) or a combination thereof; B is a metal atom or molecule (including a metal cation, as defined in the present disclosure); and X is a halogen atom or molecule or a chalcogen atom or molecule (including a halogen anion or a chalcogen anion, as defined in the present disclosure). In general formula (1), the three Xs may be the same or different from each other. As long as the photoelectric conversion element has a photoelectric conversion function, the perovskite compound converts light into electricity, and this should be taken into consideration. That is, as long as the photoelectric conversion element has a photoelectric conversion function, it is sufficient to know that it contains, for example, organic molecules, metal atoms, and halogen atoms to be a perovskite compound. Furthermore, as long as the photoelectric conversion element has a photoelectric conversion function, it is sufficient to detect elements corresponding to A, B, and X to be a perovskite compound. For example, molecules containing carbon, nitrogen, and hydrogen are suitable as organic molecules, and therefore, it is sufficient to detect carbon, nitrogen, hydrogen, metal elements, and halogen or chalcogen elements. Furthermore, as long as the photoelectric conversion element has a photoelectric conversion function, it is sufficient to detect a perovskite compound, for example, as long as cesium or rubidium is suitable as inorganic atoms, and therefore, it is sufficient to detect cesium or rubidium, metal elements, and halogen or chalcogen elements.Furthermore, it is not necessary to confirm that the photoelectric conversion layer 4 is a perovskite compound, since it is natural that the photoelectric conversion layer must have a crystalline structure in order to have a photoelectric conversion function. The photoelectric conversion layer 4 may contain compounds other than perovskite compounds.

[0025] [Hole Transport Layer] The hole transport layer 5 has a function of transporting holes generated in the photoelectric conversion layer 4. Here, for example, the hole transport layer 5 transports holes to the second electrode 7. Furthermore, it is preferable that the hole transport layer 5 has a function of blocking electrons generated in the photoelectric conversion layer 4. The hole transport layer 5 naturally has a hole transport function as long as it is disposed between the photoelectric conversion layer 4 and the first buffer layer 6a of the photoelectric conversion element 10, and as long as it is disposed on the hole transport side and the photoelectric conversion element has a photoelectric conversion function, it is not necessary to confirm the hole transport function. In other words, the hole transport layer means one disposed on the hole transport side of the photoelectric conversion layer.

[0026] The hole transport layer 5 may be formed of, for example, a spiro compound, spiro-OMeTAD (N 2 ,N 2 ,N 2 ′,N 2 ′,N 7 ,N 7 ,N 7 ′,N 7Examples of suitable polymers include N,N'-octakis(4-methoxyphenyl)-9,9'-spirobi[9H-fluorene]-2,2',7,7'-tetramine (PTAA), Poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), Poly(3-hexylthiophene-2,5-diyl) (P3HT), Poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine] (PPD), and Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). The thickness of the hole transport layer 5 may be, for example, 40 nm or more and 600 nm or less.

[0027] The hole transport layer 5 electrically connects the photoelectric conversion layer 4 and the first buffer layer 6a.

[0028] [First Buffer Layer] The first buffer layer 6a contains a metal oxide.

[0029] The electron affinity of the metal oxide is preferably greater than the ionization potential of the hole transport layer 5. In this case, carrier movement between the hole transport layer 5 and the first buffer layer 6a is facilitated, and parasitic resistance can be reduced. The metal oxide preferably contains one or more elements selected from the group consisting of Mo and W.

[0030] The metal oxide preferably contains at least one selected from the group consisting of molybdenum oxide and tungsten oxide. The electron affinity of molybdenum oxide and tungsten oxide is 5.8 to 6.0 eV, which is greater than the ionization potential (5.0 to 5.4 eV) of the hole transport layer 5.

[0031] The first buffer layer 6 a may be formed by any known method, but vapor deposition is preferred, which can suppress damage to the underlying hole transport layer 5 and photoelectric conversion layer 4 caused by the formation of the first buffer layer 6 a.

[0032] The thickness of the first buffer layer 6a is preferably, for example, 1 nm or more and 60 nm or less, more preferably 4 nm or more and 30 nm or less, and even more preferably 6 nm or more and 20 nm or less.

[0033] The first buffer layer 6a electrically connects the hole transport layer 5 and the second buffer layer 6b.

[0034] [Second Buffer Layer] The second buffer layer 6b contains a metal.

[0035] The second buffer layer 6b preferably contains a nitride containing one or more elements selected from the group consisting of Ti, Ta, Zr, and Hf. Alternatively, the second buffer layer 6b preferably contains a metal or alloy containing one or more elements selected from the group consisting of Ti and Ta. This makes it possible to obtain good adhesion between the first buffer layer 6a and the second electrode 7 and to suppress migration of metal atoms from the second electrode 7 toward the photoelectric conversion layer 4.

[0036] In this way, by providing the first buffer layer 6 a and the second buffer layer 6 b in the photoelectric conversion element 10 according to the first embodiment, it is possible to improve the adhesion between the first buffer layer 6 a and the second electrode 7, suppress the formation of the filaments, and improve the element characteristics. Therefore, it is possible to improve the adhesion between the first electrode 2 and the second electrode 7.

[0037] Furthermore, in the photoelectric conversion element 10 according to the first embodiment, the provision of the first buffer layer 6a makes it possible to suppress process damage to the hole transport layer 5 and the photoelectric conversion layer 4 during the formation of the second buffer layer 6b. Furthermore, the provision of the second buffer layer 6b makes it possible to obtain good adhesion between the first buffer layer 6a and the second electrode 7 and to realize a low-resistance connection. Therefore, the photoelectric conversion element 10 according to the first embodiment can achieve both good adhesion and good electrical conduction from the hole transport layer 5 to the second electrode 7.

[0038] On the other hand, if the first buffer layer 6a is not provided, the difference between the work function of the second buffer layer 6b and the ionization potential of the hole transport layer 5 tends to become large, making it difficult to obtain good device characteristics. In addition, process damage caused by the formation of the second buffer layer 6b causes defects in the hole transport layer 5 and the photoelectric conversion layer 4, adversely affecting the device characteristics.

[0039] Furthermore, if the second buffer layer 6b is not provided, the first buffer layer 6a and the second electrode 7 are in direct contact with each other, and therefore when a voltage is applied between the first electrode 2 and the second electrode 7, metal atoms in the second electrode 7 move toward the hole transport layer 5, easily forming filaments that penetrate the first buffer layer 6a. Furthermore, for example, these filaments may penetrate the hole transport layer 5 through film formation defects (pinholes, uneven film formation) in the hole transport layer 5, and this may easily increase the leakage current.

[0040] Therefore, by providing the first buffer layer 6a and the second buffer layer 6b, the photoelectric conversion element 10 according to the first embodiment has significantly improved element characteristics.

[0041] The thickness of the second buffer layer 6b is preferably 1 nm to 60 nm, more preferably 4 nm to 40 nm, and even more preferably 6 nm to 30 nm. The second buffer layer 6b can be formed by, for example, sputtering.

[0042] The second buffer layer 6 b connects the first buffer layer 6 a and the second electrode 7 .

[0043] [Second Electrode] The second electrode 7 is conductive and may be a counter electrode on the non-light-receiving side of the photoelectric conversion element 10 or on the side opposite the light-receiving side, or may be a transparent electrode that is light-transmitting like the first electrode 2. When the second electrode 7 is a counter electrode, it is preferable that the second electrode 7 has a light-reflecting function. In this case, the second electrode 7 preferably contains a metal or alloy containing at least one selected from the group consisting of Au, Ag, Cu, and Al. The film thickness of the second electrode 7 may be, for example, 50 nm to 300 nm. Note that the second electrode does not necessarily have to have a light-reflecting function. When the second electrode 7 is a transparent electrode, the same material as the first electrode 2 described above may be used.

[0044] The second electrode 7 preferably contains at least one element selected from the group consisting of Mn, Si, Ti, Al, Mg, and Ca at the interface on the second buffer layer 6b side. In this way, even if the second buffer layer 6b has pinholes or film formation defects such as incomplete film formation due to foreign matter, any of Mn, Si, Ti, Al, Mg, and Ca can form an oxide, thereby suppressing the generation of leakage current.

[0045] The second electrode 7 is connected to the second buffer layer 6b.

[0046] As described above, the photoelectric conversion element 10 according to the first embodiment includes a first stacked body LS1 including a first electrode 2, an electron transport layer 3 provided on the first electrode 2, a photoelectric conversion layer 4 provided on the electron transport layer 3, a hole transport layer 5 provided on the photoelectric conversion layer 4, a first buffer layer 6 a provided on the hole transport layer 5, a second buffer layer 6 b provided on the first buffer layer 6 a, and a second electrode 7 provided on the second buffer layer 6 b, wherein the first buffer layer 6 a contains a metal oxide, and the second buffer layer 6 b contains a nitride containing one or more elements selected from the group consisting of Ti, Ta, Zr, and Hf, or an alloy containing one or more elements selected from the group consisting of Ti and Ta. This improves adhesion between the first buffer layer 6 a and the second electrode 7, suppresses the formation of the filaments, and improves the element characteristics.

[0047] 2 is a cross-sectional view of a photoelectric conversion element 11 according to a second embodiment. As shown in FIG. 2, the photoelectric conversion element 11 according to the second embodiment further includes a third buffer layer 6c in addition to the photoelectric conversion element 10 according to the first embodiment.

[0048] The third buffer layer 6c is provided between the first buffer layer 6a and the second buffer layer 6b and connects to the first buffer layer 6a and the second buffer layer 6b.

[0049] The third buffer layer 6c preferably contains a metal or an alloy containing at least one element selected from the group consisting of Ti and Ta.

[0050] That is, the photoelectric conversion element 11 according to the second embodiment further includes a third buffer layer 6 c provided between the first buffer layer 6 a and the second buffer layer 6 b, and the third buffer layer 6 c contains a metal or an alloy including at least one selected from the group consisting of Ti and Ta, compared to the photoelectric conversion element 10 according to the first embodiment. In this way, the adhesion between the first buffer layer 6 a and the second buffer layer 6 b is further improved, and the element characteristics of the photoelectric conversion element 11 are improved.

[0051] 3 is a cross-sectional view of a photoelectric conversion element 12 according to a third embodiment. As shown in FIG. 3, the photoelectric conversion element 12 according to the third embodiment further includes a fourth buffer layer 6d in addition to the photoelectric conversion element 10 according to the first embodiment.

[0052] The fourth buffer layer 6 d is provided between the second buffer layer 6 b and the second electrode 7 and connects the second buffer layer 6 b and the second electrode 7 .

[0053] The fourth buffer layer 6d preferably contains a metal or an alloy containing at least one element selected from the group consisting of Ti and Ta.

[0054] That is, the photoelectric conversion element 12 according to the third embodiment further includes a fourth buffer layer 6d provided between the second buffer layer 6a and the second electrode 7, in comparison with the photoelectric conversion element 10 according to the first embodiment, and the fourth buffer layer 6d contains at least one metal or alloy selected from the group consisting of Ti and Ta. In this way, the adhesion between the second buffer layer 6b and the second electrode 7 is further improved, and the element characteristics of the photoelectric conversion element 12 are improved.

[0055] 4 is a cross-sectional view of a photoelectric conversion element 13 according to a fourth embodiment. As shown in FIG. 4, the photoelectric conversion element 13 according to the fourth embodiment further includes a third buffer layer 6c and a fourth buffer layer 6d in addition to the components of the photoelectric conversion element 10 according to the first embodiment.

[0056] The third buffer layer 6c is provided between the first buffer layer 6a and the second buffer layer 6b and connects to the first buffer layer 6a and the second buffer layer 6b. The fourth buffer layer 6d is provided between the second buffer layer 6b and the second electrode 7 and connects to the second buffer layer 6b and the second electrode 7.

[0057] Furthermore, it is preferable that the third buffer layer 6c contains a metal or an alloy including at least one selected from the group consisting of Ti and Ta, and the fourth buffer layer 6d contains at least one metal or an alloy selected from the group consisting of Ti and Ta.

[0058] The fourth buffer layer 6d preferably contains a metal or an alloy containing at least one element selected from the group consisting of Ti and Ta.

[0059] That is, the photoelectric conversion element 13 according to the fourth embodiment further includes, in comparison with the photoelectric conversion element 10 according to the first embodiment, a third buffer layer 6c provided between the first buffer layer 6a and the second buffer layer 6b, and a fourth buffer layer 6d provided between the second buffer layer 6b and the second electrode 7, wherein the third buffer layer 6c contains a metal or alloy including one or more selected from the group consisting of Ti and Ta, and the fourth buffer layer 6d contains one or more metals or alloys selected from the group consisting of Ti and Ta. In this way, adhesion between the second buffer layer 6b and the second electrode 7 is further improved, and good adhesion between the first buffer layer 6a and the second electrode 7 is obtained. Therefore, the element characteristics of the photoelectric conversion element 13 are improved.

[0060] 5 is a plan view of a photoelectric conversion module 100 according to the first embodiment. The photoelectric conversion module 100 according to the first embodiment includes the above-described photoelectric conversion element 10. The photoelectric conversion module 100 according to the first embodiment includes a plurality of the above-described photoelectric conversion elements 10, which are connected in series.

[0061] Furthermore, the photoelectric conversion modules 100b and 100c according to the second and third embodiments described below include a plurality of photoelectric conversion elements 10, 11, 12, and 13 having the laminate shown in Figures 1 to 4 described above, which are connected in series.

[0062] The photovoltaic conversion module 100 according to the first embodiment is patterned by several cuts and has regions P1, P2, and P3, as will be described later.

[0063] 5, which is a plan view of the photoelectric conversion module 100 as viewed from above, the second electrode 7 and the first electrode 2 or the electron transport layer 3 provided in the photoelectric conversion element 10 are present on the surface. A barrier layer (not shown) may be provided on these.

[0064] The barrier layer may be made of a material with high gas barrier properties, a dense inorganic material layer, or an insulating material.

[0065] Fig. 6 is a cross-sectional view of the photoelectric conversion module 100 shown in Fig. 5 taken along line XY. The photoelectric conversion module 100a shown in Fig. 6 includes, as the multiple photoelectric conversion elements 10, a first photoelectric conversion element 10a and a second photoelectric conversion element 10b adjacent to each other, and a third photoelectric conversion element 10c closest to Y. Note that the third photoelectric conversion element 10c may coincide with the first photoelectric conversion element 10a.

[0066] As shown in FIG. 6 , the photoelectric conversion element 10 (10a, 10b, 10c) includes, from the bottom, a substrate 1, a first electrode 2, an electron transport layer 3, a photoelectric conversion layer 4, a hole transport layer 5, a first buffer layer 6a, a second buffer layer 6b, and a second electrode 7, in this order.

[0067] The first stacked body LS1 includes a first electrode 2, an electron transport layer 3, a photoelectric conversion layer 4, a hole transport layer 5, a first buffer layer 6a, a second buffer layer 6b, and a second electrode 7. Therefore, the first photoelectric conversion element 10 (10a, 10b, 10c) includes the first stacked body LS1.

[0068] The method for manufacturing the photoelectric conversion module 100a according to the first embodiment is as follows.

[0069] First, a first electrode 2 is formed on a substrate 1, and then a portion of the first electrode 2 is patterned to form one or more regions P1 in which the substrate 1 is exposed. The regions P1 are preferably spaced at regular intervals. The first electrode 2 is separated into multiple islands by the regions P1, which are insulated from one another. For patterning, a laser scribing device or a mechanical scribing device can be used, for example. The width of the regions P1 may be, for example, 10 nm or more and 200 nm or less.

[0070] Subsequently, the electron transport layer 3, the photoelectric conversion layer 4, the hole transport layer 5, the first buffer layer 6a, and the second buffer layer 6b are formed in this order.

[0071] Thereafter, the second buffer layer 6b, the first buffer layer 6a, the hole transport layer 5, and the photoelectric conversion layer 4 are patterned to form a region P2 adjacent to the region P1. It is preferable that the distance between adjacent regions P2 is constant.

[0072] The formation of the region P2 can be performed using, for example, a laser scribing device or a mechanical scribing device. The width of the region P2 may be, for example, 10 nm to 200 nm. The photoelectric conversion layer 4, the hole transport layer 5, the first buffer layer 6a, and the second buffer layer 6b are separated into multiple islands by the region P2. At this time, as shown in FIG. 6 , it is preferable to also pattern the electron transport layer 3 to expose the first electrode 2. It is also preferable that the electron transport layer 3, the photoelectric conversion layer 4, the hole transport layer 5, the first buffer layer 6a, and the second buffer layer 6b are separated into multiple islands by the region P2. Note that the electron transport layer 3 may not be completely patterned, and some or all of the electron transport layer 3 may remain in some or all of the region P2.

[0073] Furthermore, at both ends of the photoelectric conversion module 100a, a region A electrically connected to the first electrode 2 of the second photoelectric conversion element 10b and a region B electrically connected to the second electrode 7 of the third photoelectric conversion element 10c are formed. Regions A and B may be formed, for example, in the same manner as in processing region P2, by patterning the second buffer layer 6b, the first buffer layer 6a, the hole transport layer 5, the photoelectric conversion layer 4, and the electron transport layer 3, so as to expose the electron transport layer 4 or the first electrode 2. It is preferable that the first electrode 2 be exposed.

[0074] Next, the second electrode 7 is formed. The second electrode 7 contacts the electron transport layer 3 or the first electrode 2 in region P2. In FIG. 6, the second electrode 7 contacts the first electrode 2 in region P2. This electrically connects the first electrode 2 of the first photoelectric conversion element 10a and the second electrode 7 of the second photoelectric conversion element 10b.

[0075] Next, the second electrode 7b is patterned to form a region P3 adjacent to the region P2, so that the second electrode 7b is separated into islands by the region P3.

[0076] In region P3, it is preferable that not only the second electrode 7 but also the second buffer layer 6b, the first buffer layer 6a, and the hole transport layer 5 are patterned to expose the photoelectric conversion layer 4. It is even more preferable that not only the second electrode 7 but also the second buffer layer 6b, the first buffer layer 6a, the hole transport layer 5, and the photoelectric conversion layer 4 are patterned to expose the electron transport layer 3. Alternatively, not only the second electrode 7 but also the second buffer layer 6b, the first buffer layer 6a, the hole transport layer 5, the photoelectric conversion layer 4, and the electron transport layer 3 may be patterned to expose the first electrode 2. Processing in this manner can suppress current leakage between adjacent photoelectric conversion elements 10 (e.g., between the first photoelectric conversion element 10a and the second photoelectric conversion element 10b), improving module performance.

[0077] The region P3 can be patterned using, for example, a laser scribing device or a mechanical scribing device.

[0078] It is preferable to cover and seal all of the photoelectric conversion elements 10 included in the photoelectric conversion module 100a with a cover glass and a sealing material (not shown), etc. In this way, the photoelectric conversion module 100a is completed.

[0079] As described above, according to the photovoltaic conversion module 100a according to the first embodiment, by providing the first buffer layer 6a and the second buffer layer 6b between the hole transport layer 5 and the second electrode 7, it is possible to improve the adhesion between the first buffer layer 6a and the second electrode 7, suppress the formation of the filaments, and improve the device characteristics, thereby improving the performance of the photovoltaic conversion module 100a.

[0080] In the first embodiment, a plurality of photoelectric conversion elements 10 are used, but instead of the photoelectric conversion elements 10, any one of the photoelectric conversion elements 11, 12, and 13 may be used.

[0081] As shown in FIG. 7, the first buffer layer 6a and the second buffer layer 6b may not be provided in the region P2.

[0082] 8, a preferred embodiment is one in which a second buffer layer 6b is provided in region P2. In this manner, contact between the first electrode 2 and the second electrode 7 via the second buffer layer 6b improves adhesion between the first electrode 2 and the second electrode 7, thereby reducing the resistance between the first electrode 2 and the second electrode 7. Also, as shown in FIG. 8, the second buffer layer 6b preferably contacts the first electrode 2 in region P2. This further improves adhesion between the first electrode 2 and the second electrode 7, thereby further reducing the resistance between the first electrode 2 and the second electrode 7. Furthermore, an electron transport layer may be provided between the second buffer layer 6b and the first electrode 2 in region P2.

[0083] 2-2. Second Embodiment Fig. 9 is a cross-sectional view of a photoelectric conversion module 100b according to a second embodiment, taken along line XY in Fig. 5. The photoelectric conversion module 100b according to the second embodiment shown in Fig. 9 includes a first photoelectric conversion element 10a and a second photoelectric conversion element 10b adjacent to each other as a plurality of photoelectric conversion elements 10, and a third photoelectric conversion element 10c closest to Y. In region P2, the first electrode 2 of the first photoelectric conversion element 10a contacts the second electrode 7 of the second photoelectric conversion element 10b via the second buffer layer 6b of the second photoelectric conversion element 10b. Note that the third photoelectric conversion element 10c may coincide with the first photoelectric conversion element 10a.

[0084] The photoelectric conversion element 10 (10a, 10b, 10c) comprises, in this order, a substrate 1, a first electrode 2, an electron transport layer 3, a photoelectric conversion layer 4, a hole transport layer 5, a first buffer layer 6a, a second buffer layer 6b, and a second electrode 7.

[0085] The first stacked body LS1 includes a first electrode 2, an electron transport layer 3, a photoelectric conversion layer 4, a hole transport layer 5, a first buffer layer 6a, a second buffer layer 6b, and a second electrode 7. Therefore, the photoelectric conversion element 10 (10a, 10b, 10c) includes the first stacked body LS1.

[0086] The second stacked body LS2 includes the first electrode 2 of the first photoelectric conversion element 10a, the second buffer layer 6b of the second photoelectric conversion element 10b, and the second electrode 7 of the second photoelectric conversion element 10b. Therefore, the photoelectric conversion module 100b includes the second stacked body LS2 in the region P2.

[0087] The method for manufacturing the photoelectric conversion module 100b according to the second embodiment is as follows.

[0088] First, a first electrode 2 is formed on a substrate 1, and then a portion of the first electrode 2 is patterned to form one or more regions P1 that expose the substrate 1. The first electrode 2 is separated into a plurality of islands by the regions P1, which are insulated from one another.

[0089] Subsequently, the electron transport layer 3, the photoelectric conversion layer 4, the hole transport layer 5, and the first buffer layer 6a are formed in this order.

[0090] Thereafter, the first buffer layer 6a, the hole transport layer 5, and the photoelectric conversion layer 4 are patterned to form a region P2 adjacent to the region P1.

[0091] The region P2 can be formed using, for example, a laser scribing device or a mechanical scribing device. The photoelectric conversion layer 4, the hole transport layer 5, and the first buffer layer 6a are separated into a plurality of islands by the region P2. At this time, as shown in FIG. 9 , it is preferable to also pattern the electron transport layer 3 to expose the first electrode 2. It is also preferable that the electron transport layer 3, the photoelectric conversion layer 4, the hole transport layer 5, and the first buffer layer 6a are separated into a plurality of islands by the region P2. Note that the electron transport layer 3 may not be completely patterned, and some or all of the electron transport layer 3 may remain in some or all of the region P2.

[0092] Furthermore, both ends of the photoelectric conversion module 100b form a region A electrically connected to the first electrode 2 of the second photoelectric conversion element 10b and a region B electrically connected to the third photoelectric conversion element 10c. Regions A and B may be formed, for example, in the same manner as in processing region P2, by patterning the first buffer layer 6a, the hole transport layer 5, the photoelectric conversion layer 4, and the electron transport layer 3, so that the electron transport layer 4 or the first electrode 2 is exposed.

[0093] Next, the second buffer layer 6b and the second electrode 7 are formed in this order. The second buffer layer 6b contacts the electron transport layer 3 or the first electrode 2 in region P2. That is, a stacked body LS2 is formed in region P2. As a result, in region P2, the first electrode 2 and the second electrode 7 contact each other via the second buffer layer 6b, improving adhesion between the first electrode 2 and the second electrode 7.

[0094] Next, a region P3 is formed at a position adjacent to the region P2 by patterning the second electrode 7. The second electrode 7 is divided into a plurality of regions by the region P3.

[0095] In region P3, it is preferable that not only the second electrode 7 but also the second buffer layer 6b, the first buffer layer 6a, and the hole transport layer 5 are patterned, thereby exposing the photoelectric conversion layer 4. It is even more preferable that not only the second electrode 7 but also the second buffer layer 6b, the first buffer layer 6a, the hole transport layer 5, and the photoelectric conversion layer 4 are patterned, thereby exposing the electron transport layer 3. Furthermore, not only the second electrode 7 but also the second buffer layer 6b, the first buffer layer 6a, the hole transport layer 5, the photoelectric conversion layer 4, and the electron transport layer 3 may be patterned, thereby exposing the first electrode 2. Processing in this manner can suppress current leakage between adjacent photoelectric conversion elements 10 (e.g., between the first photoelectric conversion element 10a and the second photoelectric conversion element 10b), thereby improving module performance.

[0096] The patterning of the region P3 can be performed using, for example, a laser scribing device or a mechanical scribing device. It is preferable to cover and seal all of the photoelectric conversion elements 10 included in the photoelectric conversion module 100a with a cover glass and a sealing material (not shown). This completes the photoelectric conversion module 100b.

[0097] As shown in FIG. 9 for the first photoelectric conversion element 10a and the second photoelectric conversion element 10b, in region P2, the first electrode 2 of the first photoelectric conversion element 10a and the second electrode 7 of the second photoelectric conversion element 10b are in contact with each other via the second buffer layer 6b of the second photoelectric conversion element 10b. That is, the photoelectric conversion module 100b has a second stack LS2 in region P2. This improves adhesion between the first electrode 2 of the first photoelectric conversion element 10a and the second electrode 7 of the second photoelectric conversion element 10b and reduces contact resistance, resulting in a low-resistance series connection between the first photoelectric conversion element 10a and the second photoelectric conversion element 10b, improving module performance. Furthermore, in region P2, it is preferable that the first electrode 2 of the first photoelectric conversion element 10a and the second buffer layer 6b of the second photoelectric conversion element 10b are in contact with each other. In region P2, the second buffer layer 6b of the second photoelectric conversion element 10b and the second electrode 7 of the second photoelectric conversion element 10b are preferably in contact with each other. This further improves module performance. In region P2, the electron transport layer 3 of the first photoelectric conversion element 10a may be located between the first electrode 2 of the first photoelectric conversion element 10a and the second buffer layer 6b of the second photoelectric conversion element 10b. In addition, a photoelectric conversion element 11 may be used instead of the photoelectric conversion element 10.

[0098] As shown in FIG. 10, a photoelectric conversion element 11 may be used instead of the photoelectric conversion element 10, and the first buffer layer 6a and the second buffer layer 6b may not be provided in the region P2.

[0099] 11 , it is preferable to use photoelectric conversion elements 11 instead of photoelectric conversion elements 10, and provide a second buffer layer 6b in region P2. That is, the photoelectric conversion module includes a first photoelectric conversion element and a second photoelectric conversion element as photoelectric conversion elements 11, and the first electrode 2 of the first photoelectric conversion element and the second electrode 7 of the second photoelectric conversion element are in contact with each other via the second buffer layer 6b of the second photoelectric conversion element. This improves adhesion between the first electrode 2 of the first photoelectric conversion element and the second electrode 7 of the second photoelectric conversion element, thereby reducing resistance between the first electrode 2 of the first photoelectric conversion element and the second electrode 7 of the second photoelectric conversion element. Also, as shown in FIG. 11 , it is preferable that the second buffer layer 6b be in contact with the first electrode 2 in region P2. The second buffer layer 6b of the second photoelectric conversion element is preferably in contact with the first electrode 2 of the first photoelectric conversion element. This further improves adhesion between the first electrode 2 and the second electrode 7, and can further reduce the resistance between the first electrode 2 of the first photoelectric conversion element and the second electrode 7 of the second photoelectric conversion element. In addition, in region P2, an electron transport layer 4 may be present between the second buffer layer 6b and the first electrode 2.

[0100] 12, a photoelectric conversion element 11 may be used instead of the photoelectric conversion element 10, and a third buffer layer 6c and a second buffer layer 6b may be provided thereon in region P2. That is, the photoelectric conversion module includes a first photoelectric conversion element 10a and a second photoelectric conversion element 10b as the photoelectric conversion element 11, and the first electrode 2 of the first photoelectric conversion element 10a and the second electrode 7 of the second photoelectric conversion element 10b are in contact with each other via the third buffer layer 6c of the second photoelectric conversion element 10b. In this manner, the adhesion between the layers from the first electrode 2 to the second electrode 7 in region P2 is improved, and contact resistance can be reduced. The photoelectric conversion module also includes a first photoelectric conversion element 10a and a second photoelectric conversion element 10b as photoelectric conversion elements 11. The first electrode 2 of the first photoelectric conversion element 10a and the second electrode 7 of the second photoelectric conversion element 10b are in contact with each other via the fourth buffer layer 6d of the second photoelectric conversion element 10b. This improves adhesion between the first electrode 2, the second electrode 2, and the second electrode 7 in region P2, thereby reducing contact resistance. Furthermore, the third buffer layer 6c preferably contacts the second electrode 7 in region P2. In this case, the adhesion between the first electrode 2 of the first photoelectric conversion element 10a and the second electrode 7 of the second photoelectric conversion element 10b in region P2 is improved, thereby reducing resistance. An electron transport layer 3 may be present between the third buffer layer 6c and the first electrode 2 in region P2.

[0101] 2-3. Third Embodiment Fig. 13 is a cross-sectional view of a photoelectric conversion module 100c according to a third embodiment. The photoelectric conversion module 100c according to the third embodiment shown in Fig. 13 includes a first photoelectric conversion element 10a and a second photoelectric conversion element 10b adjacent to each other as photoelectric conversion elements 13, and a third photoelectric conversion element 10c closest to Y. In region P2, the first electrode 2 of the first photoelectric conversion element 10a contacts the second electrode 7 of the second photoelectric conversion element 10b via the fourth buffer layer 6d of the second photoelectric conversion element 10b. Note that the third photoelectric conversion element 10c may coincide with the first photoelectric conversion element 10a.

[0102] The photoelectric conversion element 13 (10a, 10b, 10c) comprises, in this order, a substrate 1, a first electrode 2, an electron transport layer 3, a photoelectric conversion layer 4, a hole transport layer 5, a first buffer layer 6a, a third buffer layer 6c, a second buffer layer 6b, a fourth buffer layer 6d, and a second electrode 7.

[0103] The third stack LS3 also includes an electron transport layer 3 provided on the first electrode 2, a fourth buffer layer 6d provided on the electron transport layer 3, and a second electrode 7 provided on the fourth buffer layer 6d.

[0104] That is, the photoelectric conversion module 100c according to the third embodiment includes a first photoelectric conversion element 10a and a second photoelectric conversion element 10b as the photoelectric conversion elements 13 described above. The first electrode 2 of the first photoelectric conversion element 10a and the second electrode 7 of the second photoelectric conversion element 10b are in contact with each other via the fourth buffer layer 6d of the second photoelectric conversion element 10b. This improves adhesion between the first electrode 2 of the first photoelectric conversion element 10a and the second electrode 7 of the second photoelectric conversion element 10b and reduces contact resistance. This results in a low-resistance series connection between the first photoelectric conversion element 10a and the second photoelectric conversion element 10b, improving module performance. Furthermore, in region P2, the first electrode 2 of the first photoelectric conversion element 10a and the second buffer layer 6b of the second photoelectric conversion element 10b are preferably in contact with each other. In this case, it is only necessary to remove part or all of the electron transport layer 3 in the region P2. In addition, in the region P2, the fourth buffer layer 6d of the second photoelectric conversion element 10b and the second electrode 7 of the second photoelectric conversion element 10b are preferably in contact with each other. This further improves the module performance.

[0105] Furthermore, as shown in FIG. 17, a photovoltaic conversion module 100c may have an embodiment in which the first buffer layer 6a, the second buffer layer 6b, the third buffer layer 6c, and the fourth buffer layer 6d are not provided in the region P2.

[0106] 18 , the photoelectric conversion module 100c may have a fourth buffer layer 6d in the region P2. That is, the photoelectric conversion module 100c includes a first photoelectric conversion element 10a and a second photoelectric conversion element 10b as the photoelectric conversion elements 13, and the first electrode 2 of the first photoelectric conversion element 10a and the second electrode 7 of the second photoelectric conversion element 10b are in contact with each other via the fourth buffer layer 6d of the second photoelectric conversion element 10b. This improves adhesion between the first electrode 2 of the first photoelectric conversion element 10a and the second electrode 7 of the second photoelectric conversion element 10b and reduces contact resistance. As a result, the first photoelectric conversion element 10a and the second photoelectric conversion element 10b are connected in series with low resistance, improving module performance. In region P2, the first electrode 2 of the first photoelectric conversion element 10a and the fourth buffer layer 6d of the second photoelectric conversion element 10b are preferably in contact with each other, thereby improving adhesion between the first electrode 2 of the first photoelectric conversion element 10a and the second electrode 7 of the second photoelectric conversion element 10b in region P2 and improving module performance.

[0107] 19 , the photoelectric conversion module 100c may have a second buffer layer 6b and a fourth buffer layer 6d thereon in the region P2. That is, the photoelectric conversion module 100c includes a first photoelectric conversion element 10a and a second photoelectric conversion element 10b as the photoelectric conversion elements 13, and the first electrode 2 of the first photoelectric conversion element 10a and the second electrode 7 of the second photoelectric conversion element 10b are in contact with each other via the second buffer layer 6b of the second photoelectric conversion element 10b. The photoelectric conversion module 100c also includes a first photoelectric conversion element 10a and a second photoelectric conversion element 10b as the photoelectric conversion elements 13, and the first electrode 2 of the first photoelectric conversion element 10a and the second electrode 7 of the second photoelectric conversion element 10b are in contact with each other via the fourth buffer layer 6d of the second photoelectric conversion element 10b. This improves adhesion between the first electrode 2 of the first photoelectric conversion element 10a and the second electrode 7 of the second photoelectric conversion element 10b and reduces contact resistance, thereby connecting the first photoelectric conversion element 10a and the second photoelectric conversion element 10b in series with low resistance and improving module performance. Furthermore, in region P2, the first electrode 2 of the first photoelectric conversion element 10a and the second buffer layer 6b of the second photoelectric conversion element 10b are preferably in contact with each other. This improves adhesion and further improves module performance. Furthermore, in region P2, the second buffer layer 6b of the second photoelectric conversion element 10b, the fourth buffer layer 6d of the second photoelectric conversion element 10b, and the second electrode 7 of the second photoelectric conversion element 10b are preferably in contact with each other. This improves adhesion and further improves module performance. In addition, in region P2, an electron transport layer 3 of the first photoelectric conversion element 10a may be present between the first electrode 2 of the first photoelectric conversion element 10a and the second buffer layer 6b of the second photoelectric conversion element 10b.

[0108] 20 , the photoelectric conversion module 100c may have, in the region P2, a third buffer layer 6c, a second buffer layer 6b provided on the third buffer layer 6c, and a fourth buffer layer 6d provided on the second buffer layer 6b. That is, the photoelectric conversion module 100c includes a first photoelectric conversion element 10a and a second photoelectric conversion element 10c as the photoelectric conversion elements 13, and the first electrode 2 of the first photoelectric conversion element 10a and the second electrode 7 of the second photoelectric conversion element 10b are in contact with each other via the third buffer layer 6c of the second photoelectric conversion element 10b. The photoelectric conversion module 100c includes a first photoelectric conversion element 10a and a second photoelectric conversion element 10c as the photoelectric conversion elements 13, and the first electrode 2 of the first photoelectric conversion element 10a and the second electrode 7 of the second photoelectric conversion element 10b are in contact with each other via the second buffer layer 6b of the second photoelectric conversion element 10b. The photoelectric conversion module 100c also includes a first photoelectric conversion element 10a and a second photoelectric conversion element 10c as the photoelectric conversion elements 13, and the first electrode 2 of the first photoelectric conversion element 10a and the second electrode 7 of the second photoelectric conversion element 10b are in contact with each other via the fourth buffer layer 6d of the second photoelectric conversion element 10b. This improves the adhesion between the layers between the first electrode 2 and the second electrode 7 in the region P2, thereby reducing contact resistance. In region P2, the third buffer layer 6c of the second photoelectric conversion element 10b preferably contacts the first electrode 2 of the first photoelectric conversion element 10a. In this case, the resistance between the first electrode 2 of the first photoelectric conversion element 10a and the second electrode 7 of the second photoelectric conversion element 10b can be reduced, improving module performance. In region P2, the electron transport layer 3 of the first photoelectric conversion element 10a may be located between the first electrode 2 of the first photoelectric conversion element 10a and the third buffer layer 6c of the second photoelectric conversion element 10b.

[0109] As shown in FIG. 14, the photoelectric conversion element 12 may be used instead of the photoelectric conversion element 13, and no buffer layer may be provided in the region P2.

[0110] 15, the photoelectric conversion element 12 may be used instead of the photoelectric conversion element 13, and a fourth buffer layer 6d may be provided in region P2. That is, the photoelectric conversion module 100c includes a first photoelectric conversion element 10a and a second photoelectric conversion element 10b as the photoelectric conversion elements 12, and the first electrode 2 of the first photoelectric conversion element 10a and the second electrode 7 of the second photoelectric conversion element 10b are in contact with each other via the fourth buffer layer 6d of the second photoelectric conversion element 10b. This improves adhesion between the first electrode 2 and the second electrode 7 in region P2, thereby reducing contact resistance. Furthermore, in region P2, the fourth buffer layer 6d of the second photoelectric conversion element 10b preferably contacts the first electrode 2 of the first photoelectric conversion element 10a. In this case, the resistance between the first electrode 2 of the first photoelectric conversion element 10a and the second electrode 7 of the second photoelectric conversion element 10b can be reduced, improving module performance. In region P2, the electron transport layer 3 of the first photoelectric conversion element 10a may be located between the first electrode 2 of the first photoelectric conversion element 10a and the fourth buffer layer 6d of the second photoelectric conversion element 10b.

[0111] 16 , the photoelectric conversion element 12 may be used instead of the photoelectric conversion element 13, and a second buffer layer 6 b and a fourth buffer layer 6 d may be provided thereon in the region P2. That is, the photoelectric conversion module 100 c includes a first photoelectric conversion element 10 a and a second photoelectric conversion element 10 b as the photoelectric conversion elements 12, and the first electrode 2 of the first photoelectric conversion element 10 a and the second electrode 7 of the second photoelectric conversion element 10 b are in contact with each other via the second buffer layer 6 b of the second photoelectric conversion element 10 b. The photoelectric conversion module 100c also includes a first photoelectric conversion element 10a and a second photoelectric conversion element 10b as the photoelectric conversion elements 12. The first electrode 2 of the first photoelectric conversion element 10a and the second electrode 7 of the second photoelectric conversion element 10b are in contact with each other via the fourth buffer layer 6d of the second photoelectric conversion element 10b. This improves adhesion between the first electrode 2 and the second electrode 7 in region P2, thereby reducing contact resistance. Furthermore, the second buffer layer 6b of the second photoelectric conversion element 10b preferably contacts the first electrode 2 of the first photoelectric conversion element 10a in region P2. This reduces resistance between the first electrode 2 of the first photoelectric conversion element 10a and the second electrode 7 of the second photoelectric conversion element 10b, improving module performance. In addition, in region P2, an electron transport layer 3 of the first photoelectric conversion element 10a may be present between the first electrode 2 of the first photoelectric conversion element 10a and the second buffer layer 6b of the second photoelectric conversion element 10b.

[0112] This improves the adhesion between the layers of the first electrode 2 to the second electrode 7 in the region P2, thereby reducing the contact resistance.

[0113] 3. Photovoltaic Conversion System Fig. 21 is a schematic diagram of a photovoltaic conversion system 1000 according to the present disclosure. As shown in Fig. 21 , the photovoltaic conversion system 1000 according to the present disclosure 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 electrical equipment 105. The photovoltaic conversion system 1000 shown in Fig. 21 is provided with one each of the photovoltaic conversion module 100, the power conditioner 101, the distribution board 102, the power meter 103, the storage battery 104, and the electrical equipment 105, but a plurality of each may be provided.

[0114] 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.

[0115] 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 .

[0116] The power meter 103 measures the power supplied from the distribution board 102 and supplies it to the commercial power system.

[0117] 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 amount 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.

[0118] As described above, according to the photoelectric conversion element, photoelectric conversion module, and photoelectric conversion system of the present disclosure, by providing the first buffer layer 6 a and the second buffer layer 6 b between the hole transport layer 5 and the second electrode 7, it is possible to improve the adhesion between the first buffer layer 6 a and the second electrode 7, suppress the formation of the filaments, and improve the element characteristics.

[0119] Although each embodiment and each example of the present disclosure have been described in detail above, it will be readily apparent to those skilled in the art that many modifications are possible without substantially departing from the novel features and effects of the present disclosure. Therefore, all such modifications are intended to be included within the scope of the present disclosure.

[0120] For example, a term described at least once in the specification or drawings together with a different term having a broader or equivalent meaning can be replaced with that different term anywhere in the specification or drawings. Furthermore, the configurations and operations of the photoelectric conversion element, photoelectric conversion module, and photoelectric conversion system are not limited to those described in the embodiments and examples of the present disclosure, and various modifications are possible.

Claims

1. A photoelectric conversion element comprising a first stack including: a first electrode; an electron transport layer provided on the first electrode; a photoelectric conversion layer provided on the electron transport layer; a hole transport layer provided on the photoelectric conversion layer; a first buffer layer provided on the hole transport layer; a second buffer layer provided on the first buffer layer; and a second electrode provided on the second buffer layer, wherein the first buffer layer contains a metal oxide, and the second buffer layer contains a nitride containing one or more elements selected from the group consisting of Ti, Ta, Zr, and Hf, or a metal or alloy containing one or more elements selected from the group consisting of Ti and Ta.

2. The photoelectric conversion element according to claim 1, wherein the electron affinity of said first buffer layer is greater than the ionization potential of said hole transport layer.

3. The photoelectric conversion element according to claim 1 or 2, characterized in that the metal oxide contains at least one selected from the group consisting of Mo and W.

4. A photoelectric conversion element according to any one of claims 1 to 3, characterized in that the second electrode contains a metal or an alloy including one or more selected from the group consisting of Au, Ag, Cu and Al.

5. A photoelectric conversion element described in any one of claims 1 to 4, characterized in that the second electrode contains at least one element selected from the group consisting of Mn, Si, Ti, Al, Mg and Ca at the interface on the second buffer layer side.

6. A photoelectric conversion element according to any one of claims 1 to 5, further comprising a third buffer layer provided between the first buffer layer and the second buffer layer, the third buffer layer containing a metal or an alloy including at least one selected from the group consisting of Ti and Ta.

7. A photoelectric conversion element according to any one of claims 1 to 5, further comprising a fourth buffer layer provided between the second buffer layer and the second electrode, the fourth buffer layer containing one or more metals or alloys selected from the group consisting of Ti and Ta.

8. A photoelectric conversion element according to any one of claims 1 to 5, further comprising: a third buffer layer provided between the first buffer layer and the second buffer layer; and a fourth buffer layer provided between the second buffer layer and the second electrode, wherein the third buffer layer contains a metal or alloy including one or more selected from the group consisting of Ti and Ta, and the fourth buffer layer contains one or more metals or alloys selected from the group consisting of Ti and Ta.

9. A photoelectric conversion module comprising the photoelectric conversion element according to any one of claims 1 to 8.

10. The photoelectric conversion element is a photoelectric conversion element as defined in any one of claims 1, 6, 7 and 8, the photoelectric conversion element comprises a first photoelectric conversion element and a second photoelectric conversion element, and a first electrode of the first photoelectric conversion element and a second electrode of the second photoelectric conversion element are in contact with each other via a second buffer layer of the second photoelectric conversion element. The photoelectric conversion module according to claim 9.

11. The photoelectric conversion module described in claim 10, characterized in that the second buffer layer of the second photoelectric conversion element is in contact with the first electrode of the first photoelectric conversion element or the electron transport layer of the first photoelectric conversion element.

12. The photoelectric conversion element is a photoelectric conversion element as defined in any one of claims 6 and 8, the photoelectric conversion element comprises a first photoelectric conversion element and a second photoelectric conversion element, and a first electrode of the first photoelectric conversion element and a second electrode of the second photoelectric conversion element are in contact with each other via a third buffer layer of the second photoelectric conversion element. A photoelectric conversion module as described in claim 9.

13. The photoelectric conversion module described in claim 12, characterized in that the third buffer layer of the second photoelectric conversion element is in contact with the first electrode of the first photoelectric conversion element or the electron transport layer of the first photoelectric conversion element.

14. The photoelectric conversion element is a photoelectric conversion element as defined in any one of claims 7 and 8, the photoelectric conversion element comprises a first photoelectric conversion element and a second photoelectric conversion element, and a first electrode of the first photoelectric conversion element and a second electrode of the second photoelectric conversion element are in contact with each other via a fourth buffer layer of the second photoelectric conversion element. A photoelectric conversion module as described in claim 9.

15. The photoelectric conversion module described in claim 14, characterized in that the fourth buffer layer of the second photoelectric conversion element is in contact with the first electrode of the first photoelectric conversion element or the electron transport layer of the first photoelectric conversion element.

16. A photoelectric conversion system comprising: the photoelectric conversion module according to claim 9; and a control circuit.

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