Perovskite solar cell and manufacturing method for the same

Abstract

To provide a perovskite solar cell that suppresses performance degradation over time caused by moisture.SOLUTION: A perovskite solar cell 1 has, on a substrate 10, a first electrode layer 21, a first carrier transport layer 31, a perovskite layer 40, a second carrier transport layer 32, and a second electrode layer 22 stacked in this order. The main component of the perovskite layer 40 has a perovskite structure and has photoelectric conversion functionality. The perovskite layer 40 contains 2-mercaptobenzothiazole as an additive.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a perovskite solar cell and a method for manufacturing a perovskite solar cell. [Background technology]

[0002] Perovskite solar cells that use a perovskite layer as a photoelectric conversion layer are known, and Patent Document 1 discloses such a perovskite solar cell.

[0003] Such a perovskite solar cell comprises a first electrode layer (anode electrode or cathode electrode), a first carrier transport layer (hole transport film or electron transport film), a perovskite layer, a second carrier transport layer (electron transport film or hole transport film), and a second electrode layer (cathode electrode or anode electrode), which are formed in this order on a substrate such as glass or a resin film. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-013982 Summary of the Invention [Problem to be solved by the invention]

[0005] In such perovskite solar cells, the photoelectric conversion performance of the perovskite layer deteriorates over time due to moisture, resulting in a deterioration in the performance of the perovskite solar cell over time.

[0006] An object of the present invention is to provide a perovskite solar cell that suppresses performance degradation over time due to moisture, and a method for manufacturing a perovskite solar cell. [Means for solving the problem]

[0007] The perovskite solar cell according to the present invention is a perovskite solar cell in which a first electrode layer, a first carrier transport layer, a perovskite layer, a second carrier transport layer, and a second electrode layer are stacked in this order on a substrate, wherein the main component of the perovskite layer has a perovskite structure and has a photoelectric conversion function, and the perovskite layer contains 2-mercaptobenzothiazole as an additive.

[0008] The method for manufacturing a perovskite solar cell according to the present invention comprises forming a first electrode layer, a first carrier transport layer, a perovskite layer, a second carrier transport layer, and a second electrode layer in this order on a substrate, wherein in the step of forming the perovskite layer, the perovskite layer is formed by adding an additive to a main component having a perovskite structure and a photoelectric conversion function, and the additive is 2-mercaptobenzothiazole. [Effects of the Invention]

[0009] According to the present invention, it is possible to suppress performance degradation over time caused by moisture in perovskite solar cells. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view illustrating an example of a solar cell according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing another example of a solar cell according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] An example of an embodiment of the present invention will be described below with reference to the accompanying drawings. The same or equivalent parts in each drawing are designated by the same reference numerals. For convenience, hatching and reference numerals may be omitted. In such cases, reference should be made to other drawings.

[0012] (solar cells) Fig. 1 is a cross-sectional view showing an example of a solar cell according to the present embodiment, and Fig. 2 is a cross-sectional view showing another example of a solar cell according to the present embodiment. The solar cell 1 shown in Figs. 1 and 2 is a perovskite solar cell that uses a perovskite layer as a photoelectric conversion layer. The solar cell 1 includes a substrate 10, a first electrode layer 21, a first carrier transport layer 31, a perovskite layer 40, a second carrier transport layer 32, and a second electrode layer 22.

[0013] Note that the solar cell 1 shown in Fig. 1 and the solar cell 1 shown in Fig. 2 have different polarities. Specifically, in the solar cell 1 shown in Fig. 1, the first carrier transport layer 31 and the second carrier transport layer 32 are a hole transport layer (HTL) and an electron transport layer (ETL), respectively, and the first electrode layer 21 and the second electrode layer 22 are an anode and a cathode, respectively. On the other hand, in the solar cell 1 shown in Fig. 2, the first carrier transport layer 31 and the second carrier transport layer 32 are an electron transport layer (ETL) and a hole transport layer (HTL), respectively, and the first electrode layer 21 and the second electrode layer 22 are a cathode and an anode, respectively.

[0014] 1 and 2, the light-receiving surface may be the side of the substrate 10, i.e., the side of the first electrode layer 21, or the side opposite the substrate 10, i.e., the side of the second electrode layer 22. Alternatively, both the side of the substrate 10 and the side opposite the substrate 10, i.e., both the side of the first electrode layer 21 and the side of the second electrode layer 22, may function as light-receiving surfaces.

[0015] The substrate 10 may be a transparent substrate having insulating properties and optical transparency, or may be a transparent film having flexibility. Examples of transparent substrates include substrates made of glass or resin. Examples of transparent films include resin films made of polyimide, polyethylene naphthalate, polyethylene terephthalate, or other materials.

[0016] The first electrode layer 21 is formed on the substrate 10 and functions as an anode (FIG. 1) or a cathode (FIG. 2). The first electrode layer 21 is made of a transparent conductive film (Transparent Conductive Oxides: TCO) that is conductive and optically transparent. Examples of materials that can be used for the first electrode layer 21 include transparent conductive metal oxides, such as indium oxide, tin oxide, zinc oxide, titanium oxide, and composite oxides thereof. Among these, indium composite oxides containing indium oxide as the main component are preferred. Indium oxide is particularly preferred from the viewpoints of high conductivity and transparency. Furthermore, it is preferable to add a dopant to indium oxide to ensure reliability or higher conductivity. Examples of dopants include Sn, W, Zn, Ti, Ce, Zr, Mo, Al, Ga, Ge, As, Si, and S. Among these, ITO (Indium Tin Oxide), in which tin (Sn) is added to indium oxide, is particularly preferred.

[0017] When the substrate 10 side, i.e., the first electrode layer 21 side, is the light-receiving surface, the first electrode layer 21 may include a grid-shaped or slit-shaped metal electrode layer. Alternatively, when the side opposite the substrate 10, i.e., the second electrode layer 22 side, is the light-receiving surface, the first electrode layer 21 may include a planar metal electrode layer, for example, on the substrate 10 side. Examples of materials for the metal electrode layer include Ag, Au, and Cu.

[0018] The first carrier transport layer 31 is formed on the first electrode layer 21 and functions as a hole transport layer (HTL) (FIG. 1) or an electron transport layer (ETL) (FIG. 2). The first carrier transport layer 31 is made of a semiconductor material that is optically transparent.

[0019] 1, the first carrier transport layer 31 functions as a hole transport layer (HTL) that transports holes (first carriers) among carriers generated by photoelectric conversion in the perovskite layer 40 to the first electrode layer 21. Examples of main materials of the first carrier transport layer 31 serving as a hole transport layer (HTL) include nickel oxide (NiO), copper oxide (CuO), PTAA (Poly(bis(4-phenyl)(2,4,6-trimethylphenyl)amine)), and Spiro-MeOTAD.

[0020] 2, the first carrier transport layer 31 functions as an electron transport layer (ETL) that transports electrons (first carriers) among carriers generated by photoelectric conversion in the perovskite layer 40 to the first electrode layer 21. Examples of the main material of the first carrier transport layer 31 serving as the electron transport layer (ETL) include titanium oxide (TiO2), zinc oxide (ZnO), tin oxide (SnO2), and fullerene.

[0021] Examples of fullerenes include C60, C70, and their hydrides, oxides, metal complexes, and derivatives with alkyl groups or the like added thereto, such as PCBM ([6,6]-Phenyl-C61-Butyric Acid Methyl Ester). The second carrier transport layer 32 can be formed from a material containing fullerenes encapsulating lithium (Li), thereby improving the electron transport efficiency.

[0022] The first carrier transport layer 31 may also be a self-assembled monolayer (SAM) formed of, for example, 2PACz ([2-(9H-Carbazol-9-yl)ethyl]phosphonic Acid), MeO-2PACz ([2-(3,6-Dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic Acid), Me-4PACz ([4-(3,6-Dimethyl-9H-carbazol-9-yl)butyl]phosphonic Acid), etc. The first carrier transport layer 31 may also have a multilayer structure.

[0023] The perovskite layer 40 is formed on the first carrier transport layer 31 and functions as a photoelectric conversion layer. Examples of the main material (main component) of the perovskite layer 40 include compounds having a perovskite structure and represented by the following formula, which contain an organic atom A, a metal atom B, and a halogen atom X: ABX3 A includes an organic atom containing at least one of a monovalent organic ammonium ion and an amidinium ion. B includes a metal atom containing a divalent metal ion. X includes a halogen atom containing at least one of an iodide ion (I), a bromide ion (Br), a chloride ion (Cl), and a fluoride ion (F).

[0024] Examples of the main material (main component) of the perovskite layer 40 include methylammonium lead halides MAPbX3 (CH3NH3PbX3), such as MAPbI3, MAPbBr3, and MAPbCl3, and formamidinium lead halides FAPbX3 (CH(NH2)2PbX3), such as FAPbI3, FAPbBr3, and FAPbCl3. Note that multiple types of halogen atoms X may be included. For example, when iodide I and other halogen atoms X are included, examples of the main material (main component) of the perovskite layer 40 include methylammonium lead iodide MAPbI y X (3-y) (CH3NH3PbI y X (3-y) ), e.g., MAPbI y Br (3-y) , MAPbI y Cl (3-y) etc. (y is any positive integer).

[0025] The perovskite layer 40 contains an additive, such as 2-mercaptobenzothiazole (C7H5NS2).

[0026] The second carrier transport layer 32 is formed on the perovskite layer 40 and functions as an electron transport layer (ETL) (FIG. 1) or a hole transport layer (HTL) (FIG. 2). The second carrier transport layer 32 is made of an optically transparent semiconductor material.

[0027] 1, the second carrier transport layer 32 functions as an electron transport layer (ETL) that transports electrons (second carriers) among carriers generated by photoelectric conversion in the perovskite layer 40 to the second electrode layer 22. Examples of the main material of the second carrier transport layer 32 as an electron transport layer (ETL) include titanium oxide (TiO2), zinc oxide (ZnO), tin oxide (SnO2), and fullerene.

[0028] As described above, examples of fullerenes include C60, C70, and their hydrides, oxides, metal complexes, and derivatives with alkyl groups or the like added thereto, such as PCBM ([6,6]-Phenyl-C61-Butyric Acid Methyl Ester). The second carrier transport layer 32 can be formed from a material containing fullerenes encapsulating lithium (Li), thereby improving the electron transport efficiency.

[0029] When the second carrier transport layer 32 is an electron transport layer (ETL), a hole blocking layer may be provided between the second carrier transport layer 32 and the second electrode layer 22, or between the second carrier transport layer 32 and the perovskite layer 40. Examples of materials for the hole blocking layer include bathocuproine (BCP) and SnO formed by atomic layer deposition (ALD), which causes relatively little damage to the deposited layer.

[0030] Furthermore, when the second carrier transport layer 32 is an electron transport layer (ETL), an electron extraction layer may be provided between the second carrier transport layer 32 and the second electrode layer 22, or between the second carrier transport layer 32 and the perovskite layer 40. Examples of materials for the electron extraction layer include lithium (Li) and lithium fluoride (LiF).

[0031] 2, the second carrier transport layer 32 functions as a hole transport layer (HTL) that transports holes (second carriers) among the carriers generated by photoelectric conversion in the perovskite layer 40 to the second electrode layer 22. Examples of the main material of the second carrier transport layer 32 as a hole transport layer (HTL) include nickel oxide (NiO), copper oxide (CuO), PTAA (Poly(bis(4-phenyl)(2,4,6-trimethylphenyl)amine)), and Spiro-MeOTAD.

[0032] The second electrode layer 22 is formed on the second carrier transport layer 32 and functions as a cathode (FIG. 1) or an anode (FIG. 2). When the substrate 10 side, i.e., the first electrode layer 21 side, is the light-receiving surface, the second electrode layer 22 may include, for example, a planar metal electrode layer on the substrate 10 side. Alternatively, when the side opposite the substrate 10, i.e., the second electrode layer 22 side, is the light-receiving surface, the second electrode layer 22 may include a transparent conductive film (Transparent Conductive Oxide: TCO) that is conductive and light-transmitting, and may further include a grid- or slit-shaped metal electrode layer.

[0033] Materials for the transparent conductive film TCO include transparent conductive metal oxides, such as indium oxide, tin oxide, zinc oxide, titanium oxide, and composite oxides thereof. Among these, indium-based composite oxides containing indium oxide as the main component are preferred. In terms of high conductivity and transparency, indium oxide is particularly preferred. Furthermore, to ensure reliability or higher conductivity, it is preferable to add a dopant to indium oxide. Examples of dopants include Sn, W, Zn, Ti, Ce, Zr, Mo, Al, Ga, Ge, As, Si, and S. Materials for the metal electrode layer include Ag, Au, and Cu.

[0034] With this configuration, the solar cell 1 generates a current according to the light incident from the substrate 10 side, i.e., the first electrode layer 21 side, or the side opposite the substrate 10, i.e., the second electrode layer 22 side, and outputs the current to the first electrode layer 21 and the second electrode layer 22.

[0035] (Solar Cell Manufacturing Method) Next, a method for manufacturing the solar cell of this embodiment will be described with reference to FIGS.

[0036] First, a transparent conductive film is formed as the first electrode layer 21 on the substrate 10 (first electrode layer forming step). The method for forming the transparent conductive film is not particularly limited, but may be a CVD method (chemical vapor deposition method) using a vacuum chamber, an RPD method (reactive plasma deposition method), a sputtering method, or the like.

[0037] Next, a first carrier transport layer 31 is formed on the first electrode layer 21 (first carrier transport layer forming step). The method for forming the first carrier transport layer 31 is not particularly limited, but examples include dry processes such as CVD, PVD, and sputtering, and wet processes such as coating and printing. Among these, sputtering is preferred from the viewpoint of forming a dense film.

[0038] Next, a perovskite layer 40 is formed on the first carrier transport layer 31 (perovskite layer formation process). The perovskite layer 40 is formed by adding 2-mercaptobenzothiazole as an additive to the main component of the perovskite layer. For example, the perovskite layer is formed by applying a solution containing a mixture of lead iodide (PbI2), methylammonium iodide (MAI), and 2-mercaptobenzothiazole (C7H5NS2). Examples of the solvent for the solution include, but are not limited to, organic solvents such as DMF and IPA. Examples of the method for forming the perovskite layer 40 include, but are not limited to, dry processes such as vapor deposition, or wet processes such as printing, coating, or solution methods. The method for adding the 2-mercaptobenzothiazole (C7H5NS2) material is also determined in accordance with the method for forming the perovskite layer 40.

[0039] Next, the second carrier transport layer 32 is formed on the perovskite layer 40 (second carrier transport layer forming step). The method for forming the second carrier transport layer 32 is not particularly limited, but examples thereof include dry processes such as CVD, PVD, or sputtering, or vapor deposition, and wet processes such as coating and printing.

[0040] Next, the second electrode layer 22 is formed on the second carrier transport layer 32 (second electrode layer forming step). The method for forming the second electrode layer 22 is not particularly limited, but examples thereof include a CVD method using a vacuum chamber, a PVD method, or a sputtering method, or a dry process such as a vapor deposition method, or a wet process such as a printing method or a coating method. Among these, the sputtering method is preferred. As a result of the above, the perovskite solar cell 1 of this embodiment shown in FIG. 1 or 2 is obtained.

[0041] As described above, in the solar cell 1 of this embodiment, 2-mercaptobenzothiazole is added to the perovskite layer 40. This improves the moisture resistance of the perovskite layer 40, and makes it possible to suppress deterioration (deterioration) of the photoelectric conversion performance of the perovskite layer 40 over time, which is caused by moisture. Therefore, deterioration of the performance of the solar cell 1 over time, which is caused by moisture, can be suppressed.

[0042] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and various modifications and variations are possible. For example, the above-described embodiments can also be applied to the manufacture of perovskite solar cells in so-called tandem (also called multi-junction) solar cells that combine crystalline silicon solar cells or amorphous silicon thin-film solar cells with perovskite solar cells. [Explanation of symbols]

[0043] 1. Perovskite solar cells 10 Base material 21 First electrode layer (anode or cathode) 22 Second electrode layer (cathode or anode) 31 First carrier transport layer (hole transport layer or electron transport layer) 32 Second carrier transport layer (electron transport layer or hole transport layer) 40 perovskite layers

Claims

1. A perovskite solar cell comprising a first electrode layer, a first carrier transport layer, a perovskite layer, a second carrier transport layer, and a second electrode layer stacked in this order on a substrate, the main component of the perovskite layer has a perovskite structure and a photoelectric conversion function; the perovskite layer contains 2-mercaptobenzothiazole as an additive; Perovskite solar cells.

2. A method for manufacturing a perovskite solar cell, comprising forming a first electrode layer, a first carrier transport layer, a perovskite layer, a second carrier transport layer, and a second electrode layer in this order on a substrate, the method comprising: In the step of forming the perovskite layer, the perovskite layer is formed by adding an additive to a main component having a perovskite structure and a photoelectric conversion function; The additive is 2-mercaptobenzothiazole. How perovskite solar cells are manufactured.

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