Method for manufacturing solar cells and solar cells

Abstract

The objective is to provide a method for manufacturing a perovskite solar cell with high energy conversion efficiency, and a perovskite solar cell. [Solution] A method for manufacturing a solar cell, comprising the steps of: forming a first carrier transport layer on a substrate having a first electrode layer; forming a photoelectric conversion layer mainly containing an organic inorganic perovskite compound on the first carrier transport layer; forming a second carrier transport layer on the photoelectric conversion layer; and forming a second electrode layer on the second carrier transport layer, wherein, if the first electrode layer is a transparent electrode layer, the method further comprises the step of applying a dispersion containing nanoparticles made of the same material as the transparent electrode layer to the transparent electrode layer before forming the first carrier transport layer to form a nanoparticle layer; and if the second electrode layer is a transparent electrode layer, the method further comprises the step of applying a dispersion containing nanoparticles made of the same material as the transparent electrode layer to the second carrier transport layer before forming the second electrode layer to form a nanoparticle layer.

Description

[Technical Field]

[0001] One aspect of the present invention relates to a method for manufacturing a solar cell and to a solar cell. [Background technology]

[0002] One type of solar cell known is the perovskite solar cell, in which the main component of the photoelectric conversion layer is a perovskite compound.

[0003] As an example of a perovskite solar cell, Patent Document 1 describes a perovskite solar cell comprising a transparent conductive support, an electron blocking layer, a perovskite layer, an electron transport layer, a hole blocking layer, and a back electrode, wherein both the electron blocking layer and the hole blocking layer contain inorganic materials. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2017 / 073472 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] There is a need for a manufacturing method for perovskite solar cells with high energy conversion efficiency that can efficiently convert incident sunlight into electricity.

[0006] Therefore, one aspect of the present invention aims to provide a method for manufacturing a perovskite solar cell with high energy conversion efficiency and a perovskite solar cell. [Means for solving the problem]

[0007] The inventors of the present invention have found that when nanoparticles made of the same material as the transparent electrode layer are placed on a substrate equipped with a transparent electrode layer as an electrode layer in the manufacturing of a perovskite solar cell, the energy conversion efficiency of the resulting perovskite solar cell is improved, and have completed one aspect of the present invention.

[0008] In other words, the gist of one aspect of the present invention is as follows: (1) A method for manufacturing a solar cell, comprising the steps of: applying a dispersion containing nanoparticles made of the same material as the transparent electrode layer onto the transparent electrode layer of a substrate having a transparent electrode layer as a first electrode layer to form a nanoparticle layer; forming a first carrier transport layer on the nanoparticle layer; forming a photoelectric conversion layer mainly containing an organic inorganic perovskite compound on the first carrier transport layer; forming a second carrier transport layer on the photoelectric conversion layer; and forming a second electrode layer on the second carrier transport layer. (2) A method for manufacturing a solar cell, comprising the steps of: forming a first carrier transport layer on the first electrode layer of a substrate having a first electrode layer; forming a photoelectric conversion layer mainly containing an organic inorganic perovskite compound on the first carrier transport layer; forming a second carrier transport layer on the photoelectric conversion layer; applying a dispersion liquid containing nanoparticles made of a transparent conductive material to the second carrier transport layer to form a nanoparticle layer; and forming a transparent electrode layer made of the same material as the nanoparticles as a second electrode layer on the nanoparticle layer. (3) The method according to (1) or (2), wherein the transparent electrode layer is made of ITO and the ITO concentration in the dispersion is 2.0% by weight or less relative to the total weight of the dispersion. (4) The method according to (1), wherein the first carrier transport layer is a hole transport layer and the second carrier transport layer is an electron transport layer. (5) The method according to (2), wherein the first carrier transport layer is an electron transport layer and the second carrier transport layer is a hole transport layer. (6) A perovskite solar cell comprising: a substrate; a transparent electrode layer as a first electrode layer on the substrate; a nanoparticle layer made of the same material as the transparent electrode layer on the transparent electrode layer; a first carrier transport layer on the nanoparticle layer; a photoelectric conversion layer mainly composed of an organic inorganic perovskite compound on the first carrier transport layer; a second carrier transport layer on the photoelectric conversion layer; and a second electrode layer on the second carrier transport layer. (7) A perovskite solar cell comprising: a substrate; a first electrode layer on the substrate; a first carrier transport layer on the first electrode layer; a photoelectric conversion layer on the first carrier transport layer mainly containing an organic inorganic perovskite compound; a second carrier transport layer on the photoelectric conversion layer; a nanoparticle layer made of a transparent conductive material on the second carrier transport layer; and a transparent electrode layer on the nanoparticle layer as a second electrode layer, made of the same material as the nanoparticle layer. (8) The perovskite solar cell according to (6), wherein the first carrier transport layer is a hole transport layer and the second carrier transport layer is an electron transport layer. (9) The perovskite solar cell according to (7), wherein the first carrier transport layer is an electron transport layer and the second carrier transport layer is a hole transport layer. [Effects of the Invention]

[0009] According to one aspect of the present invention, it is possible to provide a method for manufacturing a perovskite solar cell with high energy conversion efficiency and a perovskite solar cell. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic cross-sectional view showing an example of the structure of a solar cell according to one embodiment of the present invention. [Figure 2] This is a schematic diagram showing a perovskite crystal structure. [Figure 3] This graph shows the reflectance (A), transmittance (B), and absorptance (C) of a perovskite solar cell in a comparative example, relative to incident light. [Figure 4]It is a graph showing the light absorption rate of incident light in a laminate formed by depositing a nanoparticle layer and a hole transport layer in this order on an ITO film of a substrate. [Figure 5] It is a graph showing the IV evaluation results of a perovskite solar cell of a comparative example. [Figure 6] It is a graph showing the IV evaluation results of a perovskite solar cell of an example.

Mode for Carrying Out the Invention

[0011] Hereinafter, a preferred embodiment of one aspect of the present invention will be described in detail. In this specification, the features of one aspect of the present invention will be described with reference to the drawings as appropriate. In the drawings, the dimensions and shapes of each part are exaggerated for clarity and do not accurately depict the actual dimensions and shapes. Therefore, the technical scope of one aspect of the present invention is not limited to the dimensions and shapes of each part shown in these drawings. Note that the method for manufacturing a solar cell and the solar cell of one aspect of the present invention are not limited to the following embodiments, and can be implemented in various forms with modifications and improvements that can be made by those skilled in the art without departing from the gist of one aspect of the present invention.

[0012] One aspect of the present invention relates to a method for manufacturing a solar cell including a photoelectric conversion layer containing an organic-inorganic perovskite compound as a main component.

[0013] The method for manufacturing a solar cell according to one aspect of the present invention includes a step of applying a dispersion liquid containing nanoparticles made of the same material as the transparent electrode layer onto a surface in contact with the transparent electrode layer as the first electrode layer and / or the second electrode layer to form a nanoparticle layer.

[0014] In one aspect of the present invention, in this step, by forming a nanoparticle layer, the reflection of incident sunlight at the electrode layer / photoelectric conversion layer interface is suppressed, the amount of incident sunlight on the photoelectric conversion layer is increased, and as a result, the energy conversion efficiency can be improved. That is, the current value of the solar cell can be improved by the effect of reducing reflected light by the nanoparticles in the nanoparticle layer.

[0015] <Solar cell configuration> First, the structure of a perovskite solar cell manufactured by the manufacturing method according to one aspect of the present invention (hereinafter also referred to as the solar cell according to one aspect of the present invention) will be described in detail. Figure 1 is a schematic cross-sectional view showing an example of the structure of the solar cell according to one aspect of the present invention.

[0016] As shown in Figure 1, in one embodiment, a solar cell C according to one aspect of the present invention comprises a substrate 1, a transparent electrode layer as a first electrode layer 2a, a nanoparticle layer N, a first carrier transport layer 3a, a photoelectric conversion layer 4, a second carrier transport layer 3b, and a second electrode layer 2b in the order described above. Although not shown in the figure, in one embodiment, a solar cell according to one aspect of the present invention may comprise a substrate, a first electrode layer, a first carrier transport layer, a photoelectric conversion layer, a second carrier transport layer, a nanoparticle layer, and a transparent electrode layer as a second electrode layer in the order described above. Although not shown in the figure, in one embodiment, a solar cell according to one aspect of the present invention may comprise a substrate, a transparent electrode layer as a first electrode layer, a nanoparticle layer, a first carrier transport layer, a photoelectric conversion layer, a second carrier transport layer, a nanoparticle layer, and a transparent electrode layer as a second electrode layer in the order described above.

[0017] Accordingly, one embodiment of the present invention is a perovskite solar cell comprising a substrate, a first electrode layer on the substrate, a first carrier transport layer on the first electrode layer, a photoelectric conversion layer on the first carrier transport layer mainly containing an organic inorganic perovskite compound, a second carrier transport layer on the photoelectric conversion layer, and a second electrode layer on the second carrier transport layer, wherein, if the substrate is a transparent substrate and the first electrode layer is a transparent electrode layer, a nanoparticle layer made of the same material as the transparent electrode layer is further included between the first electrode layer and the first carrier transport layer, and if the second electrode layer is a transparent electrode layer, a nanoparticle layer made of the same material as the transparent electrode layer is further included between the second carrier transport layer and the second electrode layer. In this embodiment, if the first electrode layer is a transparent electrode layer, the first carrier transport layer may be a hole transport layer and the second carrier transport layer may be an electron transport layer; if the second electrode layer is a transparent electrode layer, the second carrier transport layer may be a hole transport layer and the first carrier transport layer may be an electron transport layer; and if both the first and second electrode layers are transparent electrode layers, one of the first and second carrier transport layers may be a hole transport layer and the other an electron transport layer.

[0018] (Nanoparticle layer N) The nanoparticle layer N is located between the transparent electrode layer as the first electrode layer 2a and the first carrier transport layer 3a, and / or between the transparent electrode layer as the second electrode layer 2b and the second carrier transport layer 3b. The nanoparticle layer N is composed of nanoparticles (hereinafter also simply referred to as "nanoparticles") made of the same transparent conductive material as the transparent conductive material used to form the transparent electrode layer as the first electrode layer 2a and / or the second electrode layer 2b. The nanoparticle layer N suppresses the reflection of sunlight incident on the solar cell C at the interface between the first electrode layer 2a and the photoelectric conversion layer 4, and / or the interface between the second electrode layer 2b and the photoelectric conversion layer 4.

[0019] More specifically, sunlight incident on solar cell C is less likely to be reflected toward the outside world (i.e., toward the incident sunlight) at the interface between the first electrode layer 2a and the photoelectric conversion layer 4, and / or the interface between the second electrode layer 2b and the photoelectric conversion layer 4, by the nanoparticle layer N, and is more likely to be transmitted toward the photoelectric conversion layer 4.

[0020] The material of the nanoparticle layer N is the same as the transparent electrode layer, which serves as the first electrode layer and / or second electrode layer, with which the nanoparticle layer N is in contact. Therefore, the nanoparticle layer N can be modified by the first electrode layer and / or second electrode layer described below.

[0021] The average particle size of nanoparticles in nanoparticle layer N is typically 500 nm or less, 400 nm or less in one embodiment, 300 nm or less in one embodiment, 200 nm or less in one embodiment, 100 nm or less in one embodiment, 80 nm or less in one embodiment, 60 nm or less in one embodiment, 40 nm or less in one embodiment, and 20 nm or less in one embodiment. The lower limit of the average particle size of nanoparticles in nanoparticle layer N is not limited. The average particle size of nanoparticles in nanoparticle layer N is typically 1 nm or more, 2 nm or more in one embodiment, 3 nm or more in one embodiment, 4 nm or more in one embodiment, and 5 nm or more in one embodiment. Here, the average particle size of nanoparticles can be measured by dynamic light scattering (DLS). By reducing the average particle size of nanoparticles in nanoparticle layer N, reflection of sunlight at the interface can be further suppressed.

[0022] The thickness of the nanoparticle layer N is typically in the range of 1 nm to 500 nm, in one embodiment it is in the range of 1 nm to 200 nm, and in another embodiment it is in the range of 20 nm to 100 nm. The thickness of the nanoparticle layer N can be measured by microscopic (SEM) observation.

[0023] (Photoelectric conversion layer 4) Let's return to the explanation of Figure 1. The photoelectric conversion layer 4 is located between the first carrier transport layer 3a and the second carrier transport layer 3b. The photoelectric conversion layer 4 generates charge carriers by receiving light. The charge carriers generated in the photoelectric conversion layer 4 move to either the first carrier transport layer 3a or the second carrier transport layer 3b.

[0024] More specifically, the positive charge carriers, i.e., holes, generated in the photoelectric conversion layer 4 are transported to either the first electrode layer 2a or the second electrode layer 2b via the hole transport layer, whichever of the first carrier transport layer 3a and second carrier transport layer 3b corresponds to the first electrode layer 2a. Furthermore, the negative charge carriers, i.e., electrons, generated in the photoelectric conversion layer 4 are transported to either the first electrode layer 2a or the second electrode layer 2b via the electron transport layer, whichever of the first carrier transport layer 3a and the second carrier transport layer 3b is designated as the electron transport layer.

[0025] The photoelectric conversion layer 4 contains an organic-inorganic perovskite compound, and in one embodiment, it contains an organic-inorganic perovskite compound as the main component. The content of the organic-inorganic perovskite compound in the photoelectric conversion layer 4 is usually 60% by weight or more, in one embodiment it is 80% by weight or more, in one embodiment it is 90% by weight or more, in one embodiment it is 95% by weight or more, and in one embodiment it is 100% by weight. The film thickness of the photoelectric conversion layer is typically in the range of 100 nm to 1000 nm, and in one embodiment, it is in the range of 400 nm to 700 nm.

[0026] Organic-inorganic perovskite compounds are compounds that have a perovskite-type crystal structure. Figure 2 is a schematic diagram showing a perovskite-type crystal structure. As shown in Figure 2, the perovskite-type crystal structure has a cubic unit cell, with A positioned at each vertex of the cubic crystal, B positioned at the body center, and X positioned at the center of each face of the cubic crystal with B at the center. The fact that a compound has a perovskite-type crystal structure can be confirmed, for example, by X-ray diffraction measurement.

[0027] Organic-inorganic perovskite compounds can be represented, for example, by the following formula (1). ABX3(1) (In the formula, A is a monovalent cation, including at least one kind of organic cation, B is a divalent cation, and X is a monovalent anion.)

[0028] In one embodiment, in formula (1), A is at least one selected from a monovalent organic ammonium ion and a monovalent amidinium ion. Examples of the monovalent organic ammonium ion include CH3NH3 + (methylammonium ion: MA), C2H5NH3 + , C3H7NH3 + and C4H9NH3 + . Examples of the monovalent amidinium ion include HC(NH2)2 + (formamidinium ion: FA).

[0029] In one embodiment, in formula (1), A may further contain a monovalent metal ion. Examples of the monovalent metal ion include rubidium ion (Rb + ) and cesium ion (Cs + ).

[0030] In formula (1), A may be a combination of a monovalent organic ammonium ion, a monovalent amidinium ion and a monovalent metal ion. In one embodiment, in formula (1), A is a combination of two selected from the group consisting of MA or FA, or MA, FA and Cs + . In one embodiment, in formula (1), A is a mixed cation of Cs + , MA, and FA. When A is a mixed cation, the mixing ratio of each cation is not limited.

[0031] In one embodiment, in formula (1), B is a divalent metal ion, for example, lead ion (Pb 2+ ), tin ion (Sn 2+ ) and combinations thereof. In one embodiment, from the perspective of improving durability, B is Pb 2+ .

[0032] In one embodiment, in formula (1), X is a halogen ion, for example, a fluoride ion (F - ), chloride ions (Cl - ), bromide ions (Br - ) and iodide ions (I - It is at least one selected from ). In one embodiment, in formula (1), X is Cl - , Br - and I - It is at least one selected from. In one embodiment, in formula (1), X is I - That is the case.

[0033] (First carrier transport layer 3a and second carrier transport layer 3b) Let's return to the explanation of Figure 1. The first carrier transport layer 3a receives the charge carriers generated in the photoelectric conversion layer 4 and transports these charge carriers to the first electrode layer 2a. If the first carrier transport layer 3a is a hole transport layer (HTL), the first carrier transport layer 3a transports holes to the first electrode layer 2a. If the first carrier transport layer 3a is an electron transport layer (ETL), the first carrier transport layer 3a transports electrons to the first electrode layer 2a. A detailed explanation of the hole transport layer and electron transport layer will be provided later.

[0034] The second carrier transport layer 3b receives the charge carriers generated in the photoelectric conversion layer 4 and transports these charge carriers to the second electrode layer 2b. If the second carrier transport layer 3b is a hole transport layer, the second carrier transport layer 3b transports holes to the second electrode layer 2b. If the second carrier transport layer 3b is an electron transport layer, the second carrier transport layer 3b transports electrons to the second electrode layer 2b.

[0035] In the first embodiment, the first carrier transport layer 3a is an electron transport layer, and the second carrier transport layer 3b is a hole transport layer. That is, in the first embodiment, a solar cell C according to one aspect of the present invention has a substrate, a cathode, a nanoparticle layer, an electron transport layer, a photoelectric conversion layer, a hole transport layer, and an anode in the order described above. Alternatively, in the first embodiment, a solar cell C according to one aspect of the present invention has a substrate, a cathode, an electron transport layer, a photoelectric conversion layer, a hole transport layer, a nanoparticle layer, and an anode in the order described above. Alternatively, in the first embodiment, a solar cell C according to one aspect of the present invention has a substrate, a cathode, a nanoparticle layer, an electron transport layer, a photoelectric conversion layer, a hole transport layer, a nanoparticle layer, and an anode in the order described above.

[0036] Furthermore, in the second embodiment, the first carrier transport layer 3a is a hole transport layer, and the second carrier transport layer 3b is an electron transport layer. That is, in the second embodiment, the solar cell C according to one aspect of the present invention has a substrate, an anode, a nanoparticle layer N, a hole transport layer, a photoelectric conversion layer, an electron transport layer, and a cathode in the order described. Alternatively, in the second embodiment, the solar cell C according to one aspect of the present invention has a substrate, an anode, a hole transport layer, a photoelectric conversion layer, an electron transport layer, a nanoparticle layer N, and a cathode in the order described. Alternatively, in the second embodiment, the solar cell C according to one aspect of the present invention has a substrate, an anode, a nanoparticle layer N, a hole transport layer, a photoelectric conversion layer, an electron transport layer, a nanoparticle layer N, and a cathode in the order described.

[0037] The hole transport layer has the function of transporting holes generated by photoelectric conversion in the photoelectric conversion layer to the first electrode layer or the second electrode layer. As the material for the hole transport layer, known organic or inorganic materials suitable for use in hole transport layers can be used.

[0038] Organic materials that can be used as materials for the hole transport layer are not particularly limited, but include, for example, 2,2',7,7'-tetrakis-(N,N-di-4-methoxyphenylamino)-9,9'-spirobifluorene (Spiro-OMeTAD), polyethylenedioxythiophene:polystyrene sulfonic acid (PEDOT:PSS), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), 3PATAT-C3 (Non-patent literature: Journal of The American Chemistry Society 2023, No. 145, p. 7528), etc.

[0039] The inorganic materials that can be used as the material for the hole transport layer are not particularly limited, but include, for example, nickel oxide and copper oxide.

[0040] In one embodiment, in the first embodiment of the solar cell according to one aspect of the present invention, the material of the hole transport layer is one or more selected from the group consisting of Spiro-OMeTAD, PTAA, and nickel oxide. In one embodiment, in a second embodiment of the solar cell according to one aspect of the present invention, the material of the hole transport layer is one or more selected from the group consisting of PEDOT:PSS, PTAA, and nickel oxide.

[0041] The electron transport layer has the function of transporting electrons generated by photoelectric conversion in the photoelectric conversion layer to the first electrode layer or the second electrode layer. As the material for the electron transport layer, known organic or inorganic materials suitable for use in electron transport layers can be used.

[0042] Organic materials that can be used as materials for the electron transport layer are not particularly limited, but include, for example, fullerene compounds, phenanthroline derivatives (e.g., bathocuproine), polyethyleneimines, etc. Examples of fullerene compounds include fullerenes (e.g., C60 fullerene, C70 fullerene) and derivatives of fullerenes with substituents added (e.g., [6,6]-phenyl-C 61 -Methyl butyrate (also known as PCBM or

[60] PCBM), [6,6]-phenyl-C71 Examples include methyl butyrate (also known as PCBM or

[70] PCBM)).

[0043] Inorganic materials that can be used as materials for electron transport layers include titanium oxide, tin oxide, and zinc oxide.

[0044] In one embodiment, in the first embodiment of the solar cell according to one aspect of the present invention, the material of the electron transport layer is one or more selected from the group consisting of fullerene, PCBM, bathocuproine, polyethyleneimines, titanium dioxide, and tin oxide. In one embodiment, in a second embodiment of the solar cell according to one aspect of the present invention, the material of the electron transport layer is one or more selected from the group consisting of fullerenes, PCBM, bathocuproine, and polyethyleneimines.

[0045] (First electrode layer 2a and second electrode layer 2b) The first electrode layer 2a is the electrode in contact with the first carrier transport layer 3a. When the first carrier transport layer 3a is a hole transport layer, the first electrode layer 2a becomes the anode, and when the first carrier transport layer 3a is an electron transport layer, the first electrode layer 2a becomes the cathode. The second electrode layer 2b is the electrode in contact with the second carrier transport layer 3b. When the second carrier transport layer 3b is a hole transport layer, the second electrode layer 2b becomes the anode, and when the second carrier transport layer 3b is an electron transport layer, the second electrode layer 2b becomes the cathode.

[0046] As materials for the first and second electrode layers, known materials for solar cell electrodes can be used, such as metallic materials like aluminum (Al), silver (Ag), and gold (Au), transparent conductive films like indium tin oxide (ITO), indium zinc oxide (IZO), aluminum-doped zinc oxide (AZO), and fluorine-doped tin oxide (FTO), and carbon nanotubes. When the first and second electrode layers are in contact with the nanoparticle layer N, the materials for the first and second electrode layers are the same as those for the transparent electrode layer.

[0047] When the first electrode layer and / or the second electrode layer are transparent electrode layers, transparent conductive films such as ITO, IZO, AZO, and FTO can be used as the material for the transparent electrode layer.

[0048] In one embodiment, the materials for the first electrode layer and the second electrode layer are ITO, IZO, and FTO.

[0049] (Circuit board 1) The substrate 1 is a plate-shaped or film-shaped member that supports a first electrode layer 2a, a nanoparticle layer N, a first carrier transport layer 3a, a photoelectric conversion layer 4, a second carrier transport layer 3b, and a second electrode layer 2b. The material of the substrate 1 is not particularly limited, but examples include inorganic materials such as glass, organic materials such as polyethylene, polyethylene terephthalate, polyethylene naphthalate, polyimide, polyamide, polyamide-imide, liquid crystal polymer, and cycloolefin polymer, and metallic materials such as stainless steel and silicon.

[0050] The substrate 1 may be transparent or opaque. A transparent substrate is used when light is incident from the surface of the substrate. As a transparent substrate, a substrate made of glass, polyethylene terephthalate, polyethylene naphthalate, polyimide, polyamide, polyamide-imide, or cycloolefin polymer can be used. Furthermore, when light is incident from the opposite side of the substrate, the substrate can be opaque.

[0051] A solar cell according to one aspect of the present invention can be used alone or in combination with other solar cells such as silicon (Si) solar cells. When used in combination with other solar cells, for example, a tandem solar cell can be formed in which another solar cell is laminated on the second electrode layer (the electrode opposite the substrate) side of the solar cell according to one aspect of the present invention.

[0052] <Method of manufacturing solar cells> Next, a method for manufacturing solar cells, that is, a manufacturing method according to one embodiment of the present invention, will be described in more detail. In the manufacturing method according to this embodiment, a solar cell is manufactured by depositing a transparent electrode layer as the first electrode layer 2a, a nanoparticle layer N, a first carrier transport layer 3a, a photoelectric conversion layer 4, a second carrier transport layer 3b, and a second electrode layer 2b on a substrate 1 in the order described above; or by depositing a transparent electrode layer as the first electrode layer 2a, a first carrier transport layer 3a, a photoelectric conversion layer 4, a second carrier transport layer 3b, a nanoparticle layer N, and a second electrode layer 2b on a substrate 1 in the order described above; or by depositing a transparent electrode layer as the first electrode layer 2a, a nanoparticle layer N, a first carrier transport layer 3a, a photoelectric conversion layer 4, a second carrier transport layer 3b, a nanoparticle layer N, and a transparent electrode layer as the second electrode layer 2b on a substrate 1 in the order described above. The manufacturing method according to this embodiment is characterized by applying a dispersion containing nanoparticles made of the same transparent conductive material as the transparent electrode layer, which is the first electrode layer 2a and / or the second electrode layer 2b, to the surface in contact with the transparent electrode layer (in the case of the first electrode layer 2a, the surface opposite to the surface in contact with the substrate) to form a nanoparticle layer N. The film formation process for the remaining parts can be carried out using the same methods as those used for conventional photoelectric conversion elements (solar cells).

[0053] Accordingly, one embodiment of the present invention is a method for manufacturing a solar cell, comprising the steps of: forming a first carrier transport layer on a first electrode layer of a substrate having a first electrode layer; forming a photoelectric conversion layer mainly containing an organic inorganic perovskite compound on the first carrier transport layer; forming a second carrier transport layer on the photoelectric conversion layer; and forming a second electrode layer on the second carrier transport layer, wherein, if the substrate is a transparent substrate and the first electrode layer is a transparent electrode layer, the method further includes the step of applying a dispersion containing nanoparticles made of the same material as the transparent electrode layer onto the transparent electrode layer to form a nanoparticle layer before the step of forming the first carrier transport layer, and if the second electrode layer is a transparent electrode layer, the method further includes the step of applying a dispersion containing nanoparticles made of the same material as the transparent electrode layer onto the second carrier transport layer to form a nanoparticle layer between the step of forming the second carrier transport layer on the photoelectric conversion layer and the step of forming the second electrode layer on the second carrier transport layer. In this embodiment, if the first electrode layer is a transparent electrode layer, the first carrier transport layer may be a hole transport layer and the second carrier transport layer may be an electron transport layer; if the second electrode layer is a transparent electrode layer, the second carrier transport layer may be a hole transport layer and the first carrier transport layer may be an electron transport layer; and if both the first and second electrode layers are transparent electrode layers, one of the first and second carrier transport layers may be a hole transport layer and the other an electron transport layer.

[0054] The dispersion containing nanoparticles can be applied to the first electrode layer 2a and / or the second carrier transport layer 3b by known methods. The application method for the dispersion containing nanoparticles is not particularly limited and includes, for example, spin coating, inkjet coating, spray coating, blade coating, and die coating.

[0055] Dispersions containing nanoparticles can typically be applied in air at temperatures between 15°C and 35°C.

[0056] The nanoparticles are not limited to the same transparent conductive material used in the transparent electrode layers, which are the first electrode layer 2a and / or the second electrode layer 2b. In one embodiment, the average particle size of the nanoparticles is typically 500 nm or less, in one embodiment 400 nm or less, in one embodiment 300 nm or less, in one embodiment 200 nm or less, in one embodiment 100 nm or less, in one embodiment 80 nm or less, in one embodiment 60 nm or less, in one embodiment 40 nm or less, and in one embodiment 20 nm or less. The lower limit of the average particle size of the nanoparticles in the nanoparticle layer N is not limited. The average particle size of the nanoparticles in the nanoparticle layer N is typically 1 nm or more, in one embodiment 2 nm or more, in one embodiment 3 nm or more, in one embodiment 4 nm or more, and in one embodiment 5 nm or more. Here, the average particle size of the nanoparticles can be measured by dynamic light scattering (DLS). By reducing the average particle size of the nanoparticles in the nanoparticle layer N, reflection of sunlight at the interface can be further suppressed.

[0057] The concentration of nanoparticles in the dispersion containing nanoparticles is not particularly limited, but is usually 2% by weight or less, and in one embodiment, 1.5% by weight or less, relative to the total weight of the dispersion. By setting the nanoparticle concentration to the above concentration, the reflection of incident sunlight can be suppressed, and the transmission of sunlight to the photoelectric conversion layer of the solar cell and the absorption of sunlight by the photoelectric conversion layer can be improved.

[0058] The solvent for the dispersion containing nanoparticles is an alcohol, such as isopropyl alcohol (iPA). By using an alcohol as the solvent for the dispersion containing nanoparticles, the degradation of the photoelectric conversion layer and the carrier transport layer can be suppressed.

[0059] The thickness of the nanoparticle layer is typically adjusted to a range of 1 nm to 500 nm, in one embodiment to a range of 1 nm to 200 nm, and in another embodiment to a range of 20 nm to 100 nm. The thickness of the nanoparticle layer can be measured by microscopic (SEM) observation.

[0060] A manufacturing method according to one embodiment of the present invention may include a step of drying a dispersion containing coated nanoparticles. The drying step can usually be carried out by heating in air at a temperature of 80°C to 150°C.

[0061] In a manufacturing method according to one embodiment of the present invention, layers other than the nanoparticle layer can be formed by forming a film using a known method. [Examples]

[0062] One aspect of the present invention will be described in more detail below using examples. However, the technical scope of this aspect of the present invention is not limited to these examples.

[0063] As the substrate, a laminate (30 mm x 30 mm) was used, consisting of a glass plate with a photolithographed indium tin oxide (ITO) film (a transparent conductive film serving as an electrode layer) laminated on top. 3PATAT-C3 was used as the hole transport layer. ITO nanoparticle dispersion (average particle size by DLS: less than 100 nm) was used as the dispersion for forming the nanoparticle layer. CsI, MABr, FAI, PbI2, and PbBr2 were used as the perovskite. [6,6]-phenyl-C was used as the electron transport layer. 61 - Methyl butyrate (PCBM) was used.

[0064] In the experimental procedure, UV ozone treatment was performed as the surface treatment. Subsequent operations were carried out in a glove box (N2 atmosphere).

[0065] (Formation of hole transport layer) A 0.1 mM 3PATAT-C3 DMF solution was filtered before coating, and the film was deposited by spin coating. The film was then annealed at 110°C.

[0066] (Formation of nanoparticle layer) An ITO nanoparticle dispersion was diluted with dehydrated iPA to adjust the concentration, then coated by spin coating, and subsequently annealed at 110°C. The concentration was adjusted so that the ITO nanoparticle concentration was 0% by weight (no nanoparticle layer), 0.05% by weight, 0.2% by weight, 0.4% by weight, 0.6% by weight, 0.8% by weight, 1% by weight, 1.5% by weight, 2% by weight, 3% by weight, or 4% by weight relative to the total weight of the diluted dispersion. The results below are shown according to the concentration used.

[0067] (Formation of perovskite layer) A 1.2M solution of DMF / DMSO = 80 / 20 volume%, containing Cs 0.05, FA 0.79, MA 0.16, Pb 1, I 2.55, and Br 0.45 (values ​​are molar ratios), was filtered before coating, and the film was deposited by spin coating. Chlorobenzene was added dropwise as a poor solvent during the spinning process, and the film was then annealed at 110°C.

[0068] (Formation of electron transport layer) A 25 mg / ml anhydrous 2-propanol solution of PCBM was filtered before coating and then deposited by spin coating.

[0069] (Formation of electrode layer) A silver (100 nm) film was deposited by vacuum deposition after patterning with a metal mask.

[0070] Comparative Example A perovskite solar cell was manufactured by depositing a hole transport layer, a nanoparticle layer, a perovskite layer, an electron transport layer, and an electrode layer on an ITO film substrate in the order described above.

[0071] Examples A perovskite solar cell was manufactured by depositing a nanoparticle layer, a hole transport layer, a perovskite layer, an electron transport layer, and an electrode layer on an ITO film substrate in the order described above.

[0072] Figure 3 shows the reflectance (Figure 3A), transmittance (Figure 3B), and absorptance (Figure 3C) of a comparative example of a perovskite solar cell for incident light. Figure 3 shows the results for 0% by weight and 3% by weight. From Figure 3, it was found that the reflectance can be reduced by ITO nanoparticles. Furthermore, it was found that the reflectance tends to decrease as the concentration of ITO nanoparticles increases.

[0073] Figure 4 shows the light absorption rate for incident light in a laminate in which a nanoparticle layer and a hole transport layer are deposited on an ITO film on a substrate in the order described above. From Figure 4, it was found that ITO nanoparticles absorb light in the wavelength range of 350 nm to 500 nm. It was also found that absorption tends to increase as the concentration of ITO nanoparticles increases.

[0074] Figure 5 shows the IV evaluation results (PCE (Figure 5A), Jsc (Figure 5B), Voc (Figure 5C), FF (Figure 5D)) for the comparative example perovskite solar cell. From Figure 5, it can be seen that all characteristic values ​​deteriorated in the comparative example perovskite solar cell.

[0075] Figure 6 shows the IV evaluation results (PCE (Figure 6A), Jsc (Figure 6B), Voc (Figure 6C), FF (Figure 6D)) for the perovskite solar cell of the example. From Figure 6, it can be seen that Jsc is improved in the perovskite solar cell of the example. [Explanation of Symbols]

[0076] 1: Substrate, 2a: First electrode layer, 2b: Second electrode layer, 3a: First carrier transport layer, 3b: Second carrier transport layer, 4: Photoelectric conversion layer, N: Nanoparticle layer, C: Solar cell

Claims

1. A method for manufacturing a solar cell, comprising the steps of: forming a first carrier transport layer on a substrate having a first electrode layer; forming a photoelectric conversion layer mainly containing an organic-inorganic perovskite compound on the first carrier transport layer; forming a second carrier transport layer on the photoelectric conversion layer; and forming a second electrode layer on the second carrier transport layer, If the substrate is a transparent substrate and the first electrode layer is a transparent electrode layer, the process further includes, prior to the step of forming the first carrier transport layer, a dispersion containing nanoparticles made of the same material as the transparent electrode layer, to form a nanoparticle layer. When the second electrode layer is a transparent electrode layer, the process further includes, between the step of forming a second carrier transport layer on the photoelectric conversion layer and the step of forming a second electrode layer on the second carrier transport layer, a step of applying a dispersion containing nanoparticles made of the same material as the transparent electrode layer to the second carrier transport layer to form a nanoparticle layer. The aforementioned method.

2. The method according to claim 1, wherein the transparent electrode layer is made of ITO, and the ITO concentration in the dispersion is 2.0% by weight or less relative to the total weight of the dispersion.

3. The method according to claim 1, wherein when the first electrode layer is a transparent electrode layer, the first carrier transport layer is a hole transport layer and the second carrier transport layer is an electron transport layer; when the second electrode layer is a transparent electrode layer, the second carrier transport layer is a hole transport layer and the first carrier transport layer is an electron transport layer; and when both the first electrode layer and the second electrode layer are transparent electrode layers, one of the first carrier transport layer and the other of the second carrier transport layer is a hole transport layer and the other is an electron transport layer.

4. circuit board and The first electrode layer on the substrate, The first carrier transport layer on the first electrode layer, A photoelectric conversion layer containing an organic-inorganic perovskite compound as the main component on the first carrier transport layer, The second carrier transport layer on the aforementioned photoelectric conversion layer, A perovskite solar cell comprising a second electrode layer on the second carrier transport layer, If the substrate is a transparent substrate and the first electrode layer is a transparent electrode layer, then a nanoparticle layer made of the same material as the transparent electrode layer is further included between the first electrode layer and the first carrier transport layer. If the second electrode layer is a transparent electrode layer, a nanoparticle layer made of the same material as the transparent electrode layer is further included between the second carrier transport layer and the second electrode layer. The aforementioned perovskite-type solar cell.

5. The perovskite solar cell according to claim 4, wherein when the first electrode layer is a transparent electrode layer, the first carrier transport layer is a hole transport layer and the second carrier transport layer is an electron transport layer; when the second electrode layer is a transparent electrode layer, the second carrier transport layer is a hole transport layer and the first carrier transport layer is an electron transport layer; and when both the first electrode layer and the second electrode layer are transparent electrode layers, one of the first carrier transport layer and the other of the second carrier transport layer is a hole transport layer and the other is an electron transport layer.

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