Photoelectric conversion device and photoelectric conversion system

Abstract

To provide a photoelectric conversion device and a photoelectric conversion system capable of achieving good electrical contact between an upper electrode and a lower electrode within an electrode connection separation groove, while suppressing the peeling of the upper electrode.SOLUTION: A photoelectric conversion device 100 includes a substrate 20 and a photoelectric conversion element 10 including a lower electrode 11, an electron transport layer 12 provided on the lower electrode 11, a photoelectric conversion layer 13 provided on the electron transport layer 12, and an upper electrode 15 provided on the photoelectric conversion layer 13. In the connection region between two adjacent photoelectric conversion elements 10a and 10b, a separation groove P2 is provided for connecting the upper electrode 15 of the photoelectric conversion element 10a to the lower electrode 11 of the photoelectric conversion element 10b. Within the separation groove P2, the upper electrode 15 is in contact with both the upper surface of the electron transport layer 12 and the lower electrode 11.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a photoelectric conversion device and a photoelectric conversion system including a plurality of photoelectric conversion elements. [Background technology]

[0002] Typically, in a photoelectric conversion device (for example, a solar cell), a plurality of photoelectric conversion elements are formed on one surface of a substrate, and these photoelectric conversion elements are electrically connected.

[0003] When manufacturing a photovoltaic device (e.g., a solar cell), first, a lower electrode is formed on one surface of a substrate (e.g., the upper side of the substrate), and then a photovoltaic layer and a carrier transport layer (electron transport layer or hole transport layer) are formed on the surface of the lower electrode opposite the substrate. Furthermore, an electrode connection separation groove (separation groove P2 in FIGS. 1 and 2) for electrically connecting the lower electrode and the upper electrode is formed in the photovoltaic layer and the carrier transport layer by cutting processing such as mechanical processing (mechanical scribing) or laser processing (laser scribing) (e.g., Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-077104 Summary of the Invention [Problem to be solved by the invention]

[0005] The electrode connection separation groove is generally formed by etching using laser processing to expose the carrier transport layer (a carrier transport layer formed between the photoelectric conversion layer and the lower electrode, for example, an electron transport layer; hereinafter, the electron transport layer will be described as an example) or the lower electrode.

[0006] However, as a result of our extensive investigations, we found that if the carrier transport layer is exposed in the formation of the electrode connection separation groove and the carrier transport layer is brought into contact with the upper electrode to electrically connect the upper electrode and the lower electrode, the contact resistance between the upper electrode and the carrier transport layer increases, making it difficult to obtain good photoelectric conversion performance.If the carrier transport layer is removed in the formation of the electrode connection separation groove and the upper electrode and the lower electrode are brought into direct contact, the contact resistance between the upper electrode and the lower electrode decreases.

[0007] However, for example, when attempting to expose the lower electrode at the bottom of the electrode connection separation groove, stable cutting is difficult due to variations in the properties (film quality, film thickness, e.g., hardness) of each deposited layer and differences in the properties (film quality and film thickness, e.g., laser light transmittance) between layers. That is, while the separation groove should be cut to the desired depth to efficiently generate electricity from a solar cell, it is not possible to consistently form the separation groove to the desired depth, resulting in variations in the cutting depth. Therefore, selectively removing the electron transport layer on the lower electrode by laser processing is difficult. Attempting to completely remove the electron transport layer often results in excessive etching, resulting in the complete etching of the electron transport layer and the lower electrode, exposing the substrate at the bottom of the electrode connection separation groove (see Figure 8 (an enlarged cross-sectional view of region Y in Figure 2)). In this case, the absence of the lower electrode at the bottom of the electrode connection separation groove tends to result in insufficient electrical contact between the upper and lower electrodes.

[0008] Furthermore, when a metal is used for the upper electrode, the adhesion between the upper electrode and the lower electrode (usually an inorganic oxide) is weakened, making the upper electrode more likely to peel off at the bottom of the electrode connection separation groove. Furthermore, when glass is used for the substrate of the photovoltaic device, the adhesion between the upper electrode and the glass is even weaker, making the upper electrode even more likely to peel off.

[0009] Furthermore, if laser conditions are set so as not to remove the lower electrode, the electron transport layer remains unetched, which tends to result in insufficient electrical contact between the upper and lower electrodes, which is particularly noticeable when the photoelectric conversion layer contains a perovskite compound or an organic-inorganic hybrid compound material.

[0010] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a photoelectric conversion device and a photoelectric conversion system that can obtain good electrical contact between an upper electrode and a lower electrode inside an electrode connection separation groove and can suppress peeling of the upper electrode. [Means for solving the problem]

[0011] In order to solve the above problems, the following photoelectric conversion device and photoelectric conversion system are provided.

[0012] (1) Photoelectric conversion device The photoelectric conversion element of the present disclosure comprises a substrate; a first photoelectric conversion element provided on the substrate and including a first lower electrode, a first carrier transport layer provided on the first lower electrode, a first photoelectric conversion layer provided on the first carrier transport layer, and a first upper electrode provided on the first photoelectric conversion layer; and a second photoelectric conversion element provided adjacent to the first photoelectric conversion element on the substrate and including a second lower electrode, a second carrier transport layer provided on the second lower electrode, a second photoelectric conversion layer provided on the second carrier transport layer, and a second upper electrode provided on the second photoelectric conversion layer, wherein an electrode connection separation groove for connecting the first upper electrode and the second lower electrode is provided in a connection region between the first photoelectric conversion element and the second photoelectric conversion element, and within the electrode connection separation groove, the first upper electrode contacts an upper surface of the second carrier transport layer and the second lower electrode.

[0013] (2) Photoelectric conversion system A photoelectric conversion system according to the present disclosure includes the above-described photoelectric conversion device and a control circuit. [Effects of the Invention]

[0014] The photovoltaic conversion device and photovoltaic conversion system of the present disclosure provide the advantages of being able to obtain good electrical contact between the upper electrode and the lower electrode inside the electrode connection separation groove, and being able to suppress peeling of the upper electrode. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a plan view showing a basic configuration of a photoelectric conversion device according to the present disclosure. [Figure 2] 1 is a cross-sectional view showing a basic configuration of a photoelectric conversion device according to the present disclosure. [Figure 3] FIG. 4 is an enlarged cross-sectional view showing the internal configuration of a separation groove P2 in the first embodiment. [Figure 4] 10A and 10B are diagrams illustrating a method for forming a separation groove P2. [Figure 5] FIG. 10 is an enlarged cross-sectional view showing the internal configuration of a separation groove P2 in a second embodiment. [Figure 6] FIG. 11 is an enlarged cross-sectional view showing the internal configuration of a separation groove P2 in a third embodiment. [Figure 7] 1 is a schematic diagram of a photovoltaic conversion system according to the present disclosure. [Figure 8] FIG. 10 is an enlarged cross-sectional view showing an example of the internal configuration of a conventional electrode connection separation groove. [Figure 9] FIG. 10 is an enlarged cross-sectional view showing another example of the internal configuration of a conventional electrode connection separation groove. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. First, the basic configuration of a photoelectric conversion device 100 according to the present disclosure will be described with reference to FIGS. 1 and 2. FIG. 1 is a plan view of the photoelectric conversion device 100. FIG. 2 is a cross-sectional view (cross-sectional view taken along II-II in FIG. 1) of the photoelectric conversion device 100. The photoelectric conversion device 100 has a plurality of photoelectric conversion elements 10 on a substrate 20. In the following description, for convenience, the up-down direction is defined as the side on which the substrate 20 is arranged being the lower side and the side on which the photoelectric conversion elements 10 are arranged relative to the substrate 20 being the upper side; however, the orientation of the photoelectric conversion device 100 in actual use is not particularly limited.

[0017] As shown in FIG. 2 , the photoelectric conversion element 10 includes a lower electrode 11, an electron transport layer 12, a photoelectric conversion layer 13, a hole transport layer 14, and an upper electrode 15. The positions of the electron transport layer 12 and the hole transport layer 14 may be interchanged. In this embodiment, the substrate 20 is a light-transmitting substrate, and the lower electrode 11 is a conductive transparent film. That is, the photoelectric conversion device 100 has the substrate 20 side as the light-receiving surface. The upper electrode 15 may be a conductive transparent film, and the upper electrode 15 side may be the light-receiving surface. Unless otherwise specified, the term "layer" or "film" does not specify thickness or width, and includes patterned or island-shaped layers and layers with varying thicknesses. Preferably, the layer or film has a substantially constant thickness. Unless otherwise specified, the terms "approximately" and "approximately" refer to the manufacturing tolerance, and preferably allow for a variation of plus or minus 15%.

[0018] The substrate 20 is also called a base or substrate, and may be the same or include these. It may be hard and highly rigid, or it may be flexible and less rigid. 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 "transparent" or "light-transmitting" means that light passes through, but does not exclude materials that reflect or absorb even a small amount of light. It is sufficient for the substrate to be located on the light-receiving surface of the solar cell and transmit light appropriately, and can be considered synonymous with being located on the light-receiving surface of the photoelectric conversion element 10. Therefore, a substrate can be considered transparent or light-transmitting simply by being located on at least the light-receiving surface of the photoelectric conversion element 10.

[0019] The lower electrode 11 is a conductive member. It is preferable to use a light-transmitting conductive material for the lower 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 (SnO2), fluorine-doped tin oxide (FTO), and indium tin oxide (ITO). The lower electrode 11 may be formed by a known method such as sputtering or vapor deposition, and its thickness may be, for example, 30 nm to 1000 nm.

[0020] The electron transport layer 12 is a layer capable of transporting electrons. It is self-evident that, as long as a photoelectric conversion element or a light-emitting element functions, a layer disposed on the negative electrode side of the element has electron transport function, and this layer can be used as the electron transport layer. The negative electrode side can also be referred to as the electron transport side. The electron transport layer 12 may contain an inorganic oxide or may be made of an inorganic oxide. The electron transport layer 12 may contain Ti or Sn. The electron transport layer 12 may also contain titanium oxide or tin oxide. The electron transport layer 12 may also 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 may be formed by a known method such as spin coating or sputtering, and its thickness may be, for example, 10 nm to 200 nm.

[0021] The electron transport layer 12 may also be capable of inhibiting the transport of holes (hole blocking). The electron transport layer 12 may also be accompanied by a separate hole blocking layer. Alternatively, the electron transport layer 12 may not be present, and a hole blocking layer may be present instead. The electron transport layer 12 and the hole blocking layer may be the same layer. As with the electron transport layer 12, the hole blocking layer does not need to be confirmed as long as the device functions.

[0022] The photoelectric conversion layer 13 is a layer capable of absorbing light and generating electrons and holes. The photoelectric conversion layer 13 includes a perovskite compound or the like. 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.

[0023] For example, a perovskite semiconductor containing a halogen can be used as the photoelectric conversion layer 13. The photoelectric conversion layer 13, which is usually used in solar cells and has a perovskite structure, is made of Cs, FA (formamidinium), CH(NH2)2 + ), MA(methylammonium, CH3NH3 +), 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. 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 or more and 1000 nm or less.

[0024] Perovskite compounds are General formula: ABX3...(1) The photoelectric conversion element 10 is composed of a compound represented by the formula (I). 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 10 has a photoelectric conversion function, there is a degree of freedom in the configuration as described above. In general formula (1), A represents an organic molecule (including an organic group or an organic cation, as defined in the present disclosure) or an inorganic atom (including an inorganic cation, as defined in the present disclosure), or a combination thereof; B represents a metal atom (including a metal cation, as defined in the present disclosure); and X represents a halogen atom (including a halogen anion, as defined in the present disclosure). In general formula (1), the three Xs may be the same or different. When included in the photoelectric conversion layer 13, a perovskite compound can absorb light and convert it into electricity, and this fact should be taken into consideration. That is, a perovskite compound can be determined, for example, by containing 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, organic molecules containing carbon, nitrogen, and hydrogen are preferred, and therefore, carbon, nitrogen, hydrogen, metal elements, and halogen elements can be detected. Alternatively, a perovskite compound can be confirmed by having A, B, and X, for example, by 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 inorganic atoms, and therefore, cesium or rubidium, metal elements (preferably lead or tin), and halogens can be detected. Furthermore, a perovskite compound does not necessarily need to be confirmed as having a crystalline structure, since it is a natural consequence of the photoelectric conversion element 10 having a crystalline structure in order to have a photoelectric conversion function. The photoelectric conversion layer 13 may contain a compound other than the perovskite compound.

[0025] 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.

[0026] In the 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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. The halogen atom represented by X is preferably an iodine atom, from the viewpoint of enabling the perovskite compound to utilize light in a wide wavelength range. Specifically, of the three Xs, it is preferable that at least one X represents an iodine atom, and it is more preferable that all three Xs represent iodine atoms.

[0033] In the perovskite compound contained in the light absorption layer, in general formula (1), A is preferably one or more selected from the group consisting of cesium, rubidium, methylammonium, and formamidinium. In addition, in general formula (1), B is preferably one or more selected from the group consisting of lead and tin. In addition, in general formula (1), C is preferably one or more selected from the group consisting of iodine, bromine, and chlorine.

[0034] The hole transport layer 14 is a layer capable of transporting holes. The hole transport layer 14 may contain hole transport molecules. Examples of hole transport molecules 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 (polyvinyl carbazole).

[0035] As long as the photoelectric conversion element 10 is functioning, it is self-evident that the layer disposed on the positive electrode side of the element has a hole transport function, and this can be used as the hole transport layer 14. 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, there may be no hole transport layer 14, 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 does not need to be confirmed as long as the element is functioning. The positive electrode side may also be referred to as the hole transport side.

[0036] The hole transport layer 14 may contain an inorganic oxide or may consist of an inorganic oxide. The hole transport layer 14 may contain Ni or Cu. The hole transport layer 14 may contain nickel oxide or copper oxide. The hole transport layer 14 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, 10 nm to 200 nm.

[0037] The upper 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 upper electrode 15. The upper 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.

[0038] 1, the photoelectric conversion device 100 is patterned to have a plurality of photoelectric conversion elements 10 by a plurality of types of separation grooves P1 to P3. In the present disclosure, the separation grooves P1 to P3 in the photoelectric conversion device 100 are preferably formed by laser scribing, which involves etching using a laser, but may also be formed by cutting processing such as mechanical scribing.

[0039] 2, the separation groove P1 is formed after the layer that becomes the lower electrode 11 is formed (formed in the lower electrode 11), and divides the lower electrode 11 to separate two adjacent photoelectric conversion elements 10. In the following description, photoelectric conversion elements 10a and 10b in FIG. 2 are taken as an example of two adjacent photoelectric conversion elements 10.

[0040] In this case, the photoelectric conversion element 10a corresponds to the first photoelectric conversion element described in the claims, and the lower electrode 11, the electron transport layer 12, the photoelectric conversion layer 13, the hole transport layer 14, and the upper electrode 15 included in the photoelectric conversion element 10a correspond to the first lower electrode, the first electron transport layer (first carrier transport layer), the first photoelectric conversion layer, the first hole transport layer, and the first upper electrode, respectively. Similarly, the photoelectric conversion element 10b corresponds to the second photoelectric conversion element described in the claims, and the lower electrode 11, the electron transport layer 12 (second carrier transport layer), the photoelectric conversion layer 13, the hole transport layer 14, and the upper electrode 15 included in the photoelectric conversion element 10b correspond to the second lower electrode, the second electron transport layer, the second photoelectric conversion layer, the second hole transport layer, and the second upper electrode, respectively.

[0041] In this embodiment, the layer disposed between the lower electrode 11 and the photoelectric conversion layer 13 is the electron transport layer 12, and therefore the electron transport layer 12 corresponds to the carrier transport layer (first or second carrier transport layer) set forth in the claims. However, when the layer disposed between the lower electrode 11 and the photoelectric conversion layer 13 is the hole transport layer 14, the hole transport layer 14 corresponds to the carrier transport layer (first or second carrier transport layer) set forth in the claims.

[0042] The separation groove P2 is an electrode connection separation groove for electrically connecting the lower electrode 11 and the upper electrode 15. It is formed before the formation of the layer that will become the upper electrode 15, and is basically formed by etching the photoelectric conversion layer 13 and the hole transport layer 14. That is, in the separation groove P2 in FIG. 2, for the sake of simplicity, up to the electron transport layer 12 has been removed, and the upper electrode 15 is directly connected to the lower electrode 11. However, in reality, a portion of the electron transport layer 12 remains in the separation groove P2, and the separation groove P2 has a region where the electron transport layer 12 is interposed between the upper electrode 15 and the lower electrode 11, and a region where the upper electrode 15 and the lower electrode 11 are in direct contact. The separation groove P2 is filled with the material of the upper electrode 15. As a result, the upper electrode 15 of one photoelectric conversion element 10 (e.g., photoelectric conversion element 10a) and the lower electrode 11 of the other photoelectric conversion element 10 (e.g., photoelectric conversion element 10b) are connected via the separation groove P2.

[0043] In the above description, the separation groove P2 is filled with the material of the upper electrode 15. However, this does not necessarily mean that the material is filled into the separation groove P2 during the film formation process of the upper electrode 15. That is, after the separation groove P2 is formed, the filling process of filling the separation groove P2 with a conductive material and the film formation process of forming the upper electrode 15 may be performed separately. In this case, the conductive material filled into the separation groove P2 is defined as being included in the upper electrode 15. Furthermore, when the filling process and the film formation process are performed separately, the conductive material filled into the separation groove P2 and the conductive material used to form the upper electrode 15 may be the same material or different materials.

[0044] The separation groove P3 is formed after the layer that will become the upper electrode 15 is formed (formed on the electron transport layer 12, photoelectric conversion layer 13, hole transport layer 14, and upper electrode 15), and is provided to separate two adjacent photoelectric conversion elements 10 (e.g., photoelectric conversion elements 10a, 10b). In this case, the top surface of the lower electrode 11 is exposed at the bottom of the separation groove P3. Note that it is sufficient that at least the upper electrode 15 is removed from the separation groove P3, and it is preferable that the hole transport layer 14 is also removed, and it is more preferable that the photoelectric conversion layer 13 is also removed.

[0045] In this disclosure, the exposure of the top surface at the bottom of the separation trench means the exposure during the manufacturing process (before the separation trench is filled with material), and does not mean the exposure in the final structure (after the separation trench is filled with material).

[0046] In the photoelectric conversion device 100, the region between the separation groove P3 and the separation groove P1 but not including the separation groove P2 is the formation region for the photoelectric conversion elements 10. The region between the separation groove P3 and the separation groove P1 but including the separation groove P2 is a connection region for electrically connecting two adjacent photoelectric conversion elements 10.

[0047] In this way, the photoelectric conversion device 100 is configured such that the photoelectric conversion elements 10 are isolated by the isolation grooves P1 and P3, and two adjacent photoelectric conversion elements 10 are electrically connected by the isolation groove P2. As a result, the photoelectric conversion device 100 includes a plurality of photoelectric conversion elements 10 connected in series.

[0048] Photovoltaic conversion device 100 of the present disclosure has a feature in the shape of the bottom of separation groove P2 so as to obtain good electrical contact between lower electrode 11 and upper electrode 15 inside separation groove P2. This feature will be described below.

[0049] [First embodiment] FIG. 3 is an enlarged cross-sectional view (enlarged cross-sectional view of region Y in FIG. 2) showing the internal configuration of separation trench P2. As shown in FIG. 3, in photoelectric conversion device 100, a shallow region R1 where the groove is shallowly cut and a deep region R2 where the groove is deep are provided at the bottom of separation trench P2. It is preferable that a plurality of shallow regions R1 and a plurality of deep regions R2 are provided in one separation trench P2, and are alternately formed along the width direction of separation trench P2. Alternatively, shallow regions R1 and deep regions R2 may be alternately formed along the longitudinal direction of separation trench P2.

[0050] At the bottom of the separation groove P2, in the shallow region R1, the upper surface of the electron transport layer 12 is in contact with the upper electrode 15. That is, in the shallow region R1, the upper surface of the electron transport layer 12 is exposed by etching from the hole transport layer 14 to the photoelectric conversion layer 13, and then the upper electrode 15 can be formed. At this time, a portion of the electron transport layer 12 may be removed by etching, or a portion of the electron transport layer 12 may remain unremoved, thereby exposing the upper surface of the electron transport layer 12. In actual manufacturing, the electron transport layer 12 and the lower electrode 11 have similar material compositions (both inorganic oxides) and the laser power required for etching is close, making it difficult to adjust the laser power to remove up to the electron transport layer 12 and leave the lower electrode 11. For this reason, in terms of manufacturing conditions, it is easy to expose the upper surface of the electron transport layer 12 in the shallow region R1.

[0051] Furthermore, at the bottom of the separation groove P2 in the deep region R2, the upper surface of the substrate 20 is in contact with the upper electrode 15. That is, in the deep region R2, the upper surface of the substrate 20 is exposed by etching from the hole transport layer 14 to the lower electrode 11, and then the upper electrode 15 is formed. Etching that exposes the upper surface of the substrate 20 by laser processing is easy in terms of manufacturing conditions.

[0052] In this embodiment, the separation groove P2 exposes the upper surface of the electron transport layer 12 in the shallow region R1, thereby improving the adhesion of the upper electrode 15 and suppressing peeling of the upper electrode 15 at the bottom of the separation groove P2.

[0053] Furthermore, since a deep region R2 is also formed in the separation trench P2, the side end surface of the lower electrode 11 is exposed at the boundary surface (F1 in FIG. 3) between the shallow region R1 and the deep region R2. The upper electrode 15 formed inside the separation trench P2 is connected to the side end surface of the lower electrode 11 exposed at the boundary surface F1, thereby achieving good electrical contact with the lower electrode 11. Furthermore, by providing the shallow region R1 and the deep region R2, the contact area between the upper electrode 15 and the separation trench P2 is increased, further suppressing peeling of the upper electrode 15.

[0054] Next, a method for forming the separation groove P2 will be described. The separation groove P2 can be formed by, for example, the following (Method 1) to (Method 3).

[0055] (Method 1) When forming separation grooves P2 by laser processing, typically, a laser spot having a spot diameter d is laser scanned multiple times over the area where separation grooves P2 are to be formed, while being shifted by a pitch p in the sub-scanning direction, as shown in Figure 4. The laser scanning direction (main scanning direction) is the longitudinal direction of separation grooves P2. Furthermore, the pitch p is set to be less than the spot diameter d so that adjacent laser scan lines partially overlap in the sub-scanning direction.

[0056] At this time, by varying the laser power of the irradiated laser, shallow region R1 and deep region R2 can be formed at the bottom of separation groove P2. That is, by alternately providing laser scan lines with relatively weak laser power and laser scan lines with relatively strong laser power, shallow region R1 can be formed by the laser scan lines with weak laser power, and deep region R2 can be formed by the laser scan lines with strong laser power.

[0057] (Method 2) As a second method, it is also possible to form shallow region R1 and deep region R2 at the bottom of separation groove P2 without changing the laser power of the irradiated laser. As described above, adjacent laser scan lines partially overlap in the sub-scanning direction, so by appropriately setting the pitch p, the amount of etching in the overlapping region of the laser scan lines can be increased, and deep region R2 can be formed in the overlapping region (the non-overlapping region becomes shallow region R1).

[0058] Typically, the laser intensity distribution within a laser spot is not uniform, with the intensity being higher at the center of the spot and lower at the periphery. Therefore, if the pitch p is relatively large and the overlapping area of ​​the laser scan lines is small, it is difficult to form the deep region R2 in the overlapping area. That is, to form the deep region R2 at the bottom of the separation groove P2 using Method 2, it is preferable to set the pitch p relatively small and increase the overlapping area of ​​the laser scan lines relative to the spot diameter d.

[0059] (Method 3) The electron transport layer 12 is exposed by the first laser processing, and then the region where the deep region R2 is to be formed is irradiated with a second laser to etch the electron transport layer 12 and the lower electrode 11, thereby forming the deep region R2. The area where the second laser processing is not performed becomes the shallow region R1.

[0060] Second Embodiment 5 is an enlarged cross-sectional view (enlarged cross-sectional view of region Y in FIG. 2) showing the internal structure of separation trench P2 in the second embodiment. In photovoltaic device 100 shown in FIG. 5, in deep region R2, the lower electrode 11 is etched away, but the lower electrode 11 is not completely removed, and the upper surface of substrate 20 is not exposed. In other words, after the formation of upper electrode 15, the upper surface of lower electrode 11 is in contact with upper electrode 15 at the bottom of separation trench P2 in deep region R2.

[0061] In the configuration of this embodiment, the upper surface of the electron transport layer 12 is exposed in the shallow region R1, which improves the adhesion of the upper electrode 15 and suppresses peeling of the upper electrode 15 at the bottom of the separation groove P2.

[0062] Furthermore, since the upper electrode 15 and the lower electrode 11 are in contact with each other in the deep region R2, good electrical contact can be obtained between the upper electrode 15 and the lower electrode 11. Furthermore, by providing the shallow region R1 and the deep region R2, the contact area between the upper electrode 15 and the separation groove P2 increases, which further suppresses peeling of the upper electrode 15.

[0063] Third Embodiment Fig. 6 is an enlarged cross-sectional view (enlarged cross-sectional view of region Y in Fig. 2) showing the internal configuration of separation groove P2 in the third embodiment. In photovoltaic device 100 shown in Fig. 6, adhesive layer 16 formed in the shape of a plurality of discrete islands is provided on the upper surface of shallow region R1. Note that the configuration of deep region R2 in Fig. 6 is the same as that of the first embodiment (Fig. 3), but may also be the same as that of the second embodiment (Fig. 5).

[0064] In this embodiment, similarly to the first and second embodiments, good electrical contact can be obtained between the upper electrode 15 and the lower electrode 11 inside the separation trench P2, and peeling of the upper electrode 15 can be suppressed. In addition, the provision of the island-shaped adhesive layer 16 increases the contact area on the lower surface of the upper electrode 15, further improving the adhesion (adhesion) of the upper electrode 15 on the upper surface of the shallow region R1.

[0065] The adhesive layer 16 is preferably made of a material that has high adhesion to the layer below it (the electron transport layer 12 in FIG. 6 ), and may contain either Pb or Sn. For example, when forming the separation groove P2, a portion of the photoelectric conversion layer 13 may be present on the upper surface of the shallow region R1, and the remaining portion of the photoelectric conversion layer 13 may be used as the adhesive layer 16. Furthermore, the adhesive layer 16 may be formed by exposing a portion of the photoelectric conversion layer 13 to air or moisture, thereby containing one or more of lead iodide, lead bromide, tin iodide, and tin bromide. Alternatively, the adhesive layer 16 may be formed by adding a material that will become the adhesive layer 16 to the upper surface of the shallow region R1 after the separation groove P2 is formed by laser processing (for example, by spraying and depositing the material that will become the adhesive layer 16 on the upper surface of the shallow region R1).

[0066] [Fourth embodiment] In this embodiment, a photovoltaic conversion system according to the present disclosure will be described. FIG. 7 is a schematic diagram of a photovoltaic conversion system 1000 according to the present disclosure. As shown in FIG. 7, the photovoltaic conversion system 1000 includes the above-described photovoltaic conversion device 100, a power conditioner 101 as an example of a control circuit, 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. 7 includes one each of the photovoltaic conversion device 100, the power conditioner 101, the distribution board 102, the power meter 103, the storage battery 104, and the electrical device 105, but multiple of each may be provided. That is, the photovoltaic conversion system 1000 includes a photovoltaic conversion module 100 and a control circuit. The control circuit may be any device capable of controlling the current or voltage output from the photovoltaic conversion module 100.

[0067] The power conditioner 101 controls the current and voltage so that the power output from the photovoltaic conversion device 100 is optimized, and also performs the desired power distribution while monitoring the output power of the photovoltaic conversion device 100 and the charge level 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.

[0068] 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 .

[0069] The power meter 103 measures the power supplied from the distribution board 102 and supplies it to the commercial power system.

[0070] The electric 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 device 100, the charge amount of the storage battery 104, and the power consumption of the electric device 105, and supplies AC power to the distribution board 102, DC power to the storage battery 104, and AC power to the electric device 105. If the electric device 105 is for DC power, DC power may be supplied.

[0071] Although the photoelectric conversion device 100 in each of the above embodiments illustrates the photoelectric conversion layer 13 having a perovskite structure, the photoelectric conversion layer of the present disclosure is not limited to one having a perovskite structure. However, the photoelectric conversion layer 13 having a perovskite structure requires relatively strict adjustment of the laser power, and the problems described in the background art become more pronounced, so it is preferable to apply the configuration of the present disclosure.

[0072] 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. [Explanation of symbols]

[0073] 10 Photoelectric conversion element 20 Substrate 11 Lower electrode 12 Electron transport layer 13 Photoelectric conversion layer 14 Hole transport layer 15 Upper electrode 16 Adhesive layer 100 Photoelectric conversion device 101 Power conditioner (control circuit) 1000 Photoelectric Conversion System P1~P3 Separation groove R1 Shallow region R2 deep region

Claims

1. A substrate; a first photoelectric conversion element provided on the substrate, the first photoelectric conversion element including a first lower electrode, a first carrier transport layer provided on the first lower electrode, a first photoelectric conversion layer provided on the first carrier transport layer, and a first upper electrode provided on the first photoelectric conversion layer; a second photoelectric conversion element provided adjacent to the first photoelectric conversion element on the substrate, the second photoelectric conversion element including a second lower electrode, a second carrier transport layer provided on the second lower electrode, a second photoelectric conversion layer provided on the second carrier transport layer, and a second upper electrode provided on the second photoelectric conversion layer; Equipped with an electrode connection separation groove for connecting the first upper electrode and the second lower electrode is provided in a connection region between the first photoelectric conversion element and the second photoelectric conversion element; The photoelectric conversion device, wherein the first upper electrode is in contact with an upper surface of the second carrier transport layer and the second lower electrode within the electrode connection separation groove.

2. The photoelectric conversion device according to claim 1 , a photoelectric conversion device comprising an adhesive layer formed in the shape of a plurality of discrete islands between the first upper electrode and the second carrier transport layer inside the electrode connection separation groove;

3. The photoelectric conversion device according to claim 2, The photoelectric conversion device, wherein the adhesive layer contains either Pb or Sn.

4. The photoelectric conversion device according to claim 2, The photoelectric conversion device, wherein the adhesive layer contains at least one of lead iodide, lead bromide, tin iodide, and tin bromide.

5. The photoelectric conversion device according to claim 1 , The photoelectric conversion device, wherein the second carrier transport layer contains an inorganic oxide.

6. The photoelectric conversion device according to claim 5, The photoelectric conversion device, wherein the second carrier transport layer contains Ni or Cu.

7. The photoelectric conversion device according to claim 5, The photoelectric conversion device, wherein the second carrier transport layer contains nickel oxide or copper oxide.

8. The photoelectric conversion device according to claim 5, The photoelectric conversion device, wherein the second carrier transport layer contains Ti or Sn.

9. The photoelectric conversion device according to claim 5, The photoelectric conversion device, wherein the second carrier transport layer contains titanium oxide or tin oxide.

10. The photoelectric conversion device according to claim 1 , A photoelectric conversion device characterized in that the first 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.

11. A photoelectric conversion system comprising the photoelectric conversion device according to claim 1 and a control circuit.

Images