Method for manufacturing solar battery cell, method for manufacturing solar battery module, solar battery cell, and solar battery module

Abstract

A method for manufacturing a solar battery cell (100) according to the present disclosure is characterized by comprising: a step for forming an electron transport layer (20) on a first electrode (10); a step for forming a light absorption layer (30) including a perovskite layer on the electron transport layer (20); a step for forming a hybrid hole transport layer (40) on the light absorption layer (30); and a step for forming a second electrode (50) on the hybrid hole transport layer (40). The method is also characterized in that, in the step for forming the hybrid hole transport layer (40), a solution containing an inorganic substance is added to a solution containing an organic substance.

Description

Method for manufacturing a solar cell, method for manufacturing a solar cell module, solar cell, and solar cell module

[0001] The present disclosure relates to a method for manufacturing a solar cell, a method for manufacturing a solar cell module, a solar cell, and a solar cell module. This application claims priority to Japanese Patent Application No. 2023-137811, filed on August 28, 2023, the contents of which are incorporated herein by reference.

[0002] Solar cells have been disclosed in the past.

[0003] For example, Patent Document 1 discloses an organic-inorganic hybrid solar cell including a first electrode, a first common layer provided on the first electrode, a light absorbing layer including a compound with a perovskite structure provided on the first common layer, a second common layer provided on the light absorbing layer, a third common layer provided on the second common layer, and a second electrode provided on the third common layer, wherein the first common layer includes first metal oxide nanoparticles, the second common layer includes second metal oxide nanoparticles, and the third common layer includes a fullerene derivative.

[0004] Special table 2019-522371 publication

[0005] However, in terms of conversion efficiency, there is a problem of a difference in valence band energy level between the light absorption layer, which has a deep valence band energy level, and the hole transport layer, which has a shallow valence band energy level. The trapping of defect levels in the inorganic material layer reduces the carrier extraction efficiency and decreases the device efficiency. On the other hand, in terms of durability, the penetration of water molecules into the light absorption layer causes the decomposition of the perovskite structure and the formation of PbI. ２ Heavy deposition reduces durability.

[0006] In view of the above problems, the present disclosure provides a solar cell with improved conversion efficiency and durability, and a method for manufacturing the solar cell.

[0007] In one aspect of the present disclosure, a method for manufacturing a semiconductor device includes the steps of forming an electron transport layer on a first electrode, forming a light absorbing layer including a perovskite layer on the electron transport layer, forming a hybrid hole transport layer on the light absorbing layer, and forming an electrode on the hybrid hole transport layer, wherein the step of forming the hybrid hole transport layer is characterized by adding a solution including an inorganic substance to a solution including an organic substance.

[0008] Another aspect of the present disclosure is characterized in that solar cells manufactured by the solar cell manufacturing method are integrated and modularized.

[0009] In another aspect of the present disclosure, a light-emitting device includes a first electrode, an electron transport layer formed on the first electrode, a light-absorbing layer formed on the electron transport layer and including a perovskite layer, a hybrid hole transport layer formed on the light-absorbing layer, and an electrode formed on the hybrid hole transport layer, wherein the hybrid hole transport layer contains an organic material and an inorganic material.

[0010] Another aspect of the present disclosure is a solar cell module in which solar cells are integrated and modularized, characterized in that the first electrode is a transparent conductive substrate.

[0011] As described above, according to the present disclosure, it is possible to provide a solar cell, a solar cell module, a method for manufacturing a solar cell, and a method for manufacturing a solar cell module, with improved conversion efficiency and durability.

[0012] FIG. 1 is a schematic cross-sectional view of a solar cell according to the present disclosure. FIG. 2 is an enlarged cross-sectional view of the periphery of the hybrid hole transport layer shown in FIG. 1. FIG. 3 shows energy levels in the inorganic layer and the organic layer of the light absorbing layer and the hybrid hole transport layer. FIG. 4 is an explanatory diagram of the conduction band level and the valence band level. FIG. 5 is a schematic cross-sectional view of a solar cell module including a solar cell according to the present disclosure. FIG. 6 is a schematic cross-sectional view of a solar cell module including a solar cell (variant) according to the present disclosure. FIG. 7 is a diagram in which a schematic cross-sectional view of one solar cell included in a solar cell module is superimposed on an equivalent circuit of the solar cell. FIG. 8 is an equivalent circuit of a solar cell module. FIG. 9 is a process diagram of a method for manufacturing a solar cell according to the present disclosure. FIG. 10 is an explanatory diagram of a manufacturing method in which a perovskite compound solution is applied and dried to form a light absorbing layer.

[0013] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. Note that the embodiments described below do not unduly limit the content of the present disclosure described in the claims, and not all of the configurations described in the embodiments are necessarily essential to the solutions of the present disclosure. In addition, the light incident side will be expressed as the lower side, and the side opposite to the light incident side will be expressed as the upper side.

[0014] 1. Solar Cell Fig. 1 is a schematic cross-sectional view of a solar cell 100 according to the present disclosure. As shown in Fig. 1, the solar cell 100 according to the present disclosure includes a first electrode 10, an electron transport layer 20 formed on the first electrode 10, a light absorbing layer 30 formed on the electron transport layer 20, a hybrid hole transport layer 40 formed on the light absorbing layer 30, and a second electrode 50 formed on the hybrid hole transport layer 40. The first electrode 10 is in contact with the electron transport layer 20, the electron transport layer 20 is in contact with the light absorbing layer 30, the light absorbing layer 30 is in contact with the hybrid hole transport layer 40, and the hybrid hole transport layer 40 is in contact with the second electrode 50. Each component will be described in detail below.

[0015] [First Electrode] The first electrode 10 is a conductive member. A suitable example is a transparent conductive substrate. The transparent conductive substrate 10 includes a transparent base 11 and a transparent conductive film 12, as shown in FIG.

[0016] (Transparent Substrate) The transparent substrate 11 is the base of the solar cell 100 and is the same as or includes the substrate or base material. It is made of a transparent material. The transparent substrate 11 is disposed on the light-receiving side of the solar cell 100 (any side that allows light to enter, as in the present disclosure). Furthermore, during the manufacturing process of the solar cell 100, the electron transport layer 20, the light absorption layer 30, and the like are laminated on the transparent conductive substrate 10. Note that "transparent" means that it transmits light, but does not exclude materials that reflect light even slightly. It is sufficient that it is disposed on the light-receiving side of the solar cell and can transmit light appropriately, and can be considered synonymous with being disposed on the light-receiving side of the solar cell. Therefore, being disposed at least on the light-receiving side can be considered transparent. In other words, a transparent substrate refers to a substrate disposed on the light-receiving side of the solar cell.

[0017] Examples of materials for the transparent substrate 11 include transparent glass (more specifically, soda-lime glass, alkali-free glass, etc.), and transparent resins such as heat-resistant organic films of polyethylene, polyethylene terephthalate, etc. By using a flexible substrate, the solar cell itself can be made flexible.

[0018] When the material of the transparent substrate 11 is a transparent resin such as an organic film, the solar cell 100 may have a barrier layer on the transparent substrate 11. In this way, it is possible to prevent moisture and the like from penetrating into the light absorbing layer 30.

[0019] Unless otherwise specified, the transparent substrate 11 on the light-receiving side is not limited in thickness, but typically has a thickness of about 300 μm to 1500 μm, which reduces the risk of moisture and the like penetrating the light-absorbing layer 30 and reducing the conversion efficiency and durability of the solar cell 100. On the other hand, the second electrode 50 (hereinafter simply referred to as electrode 50) and hole transport layer on the non-light-receiving side (including a portion that reflects light, the same applies hereinafter) are not limited in thickness, but typically have a thickness of less than 50 μm to 300 μm, which is thin, which increases the risk of moisture and the like penetrating the light-absorbing layer 30 and reducing the conversion efficiency and durability of the solar cell 100.

[0020] Therefore, by providing the hybrid hole transport layer 40 of the solar cell 100 according to the present disclosure, the conversion efficiency and durability are prevented from decreasing and are improved, as will be described later.

[0021] (Transparent conductive film) The transparent conductive film 12 is a conductive film on the light-receiving surface side of the solar cell 100. Examples of materials that constitute the transparent conductive film 12 include transparent conductive materials (particularly, transparent conductive oxides (TCOs)) and non-transparent conductive materials. Examples of transparent conductive materials include copper iodide (CuI), indium tin oxide (ITO), and tin oxide (SnO ２ Examples of suitable conductive materials include fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), indium zinc oxide (IZO), and gallium-doped zinc oxide (GZO). A non-transparent conductive material refers to a material that, even if its physical properties are non-transparent at a certain thickness, can become transparent depending on the thickness of the material and can therefore be used as a conductive film on the light-receiving surface of a solar cell 100. The term "film" does not specify thickness or width, and includes patterned or island-shaped structures and structures with portions of varying thickness. A film preferably refers to a member with a substantially constant thickness. Unless otherwise specified, "approximately" refers to the degree of manufacturing error, and preferably indicates that a variation of plus or minus 15% of the numerical value is allowed. Note that chemical formulas are representative examples and may refer to the names of compounds (as in the present disclosure). Furthermore, while stoichiometric composition ratios in the chemical formulas are desirable, they do not necessarily have to be stoichiometric (as in the present disclosure).

[0022] [Electron Transport Layer] The electron transport layer 20 is a layer capable of transporting electrons. It has the function of transporting electrons generated by photoexcitation in the perovskite layer (hereinafter referred to as the perovskite compound) contained in the light absorbing layer 30 to the transparent conductive film 12. It is also preferable that the electron transport layer 20 has the function of blocking holes generated by photoexcitation in the perovskite compound. As long as the solar cell 100 has a photoelectric conversion function, it naturally has the electron transport function as long as it is located on the electron transport side of the light absorbing layer or on the electron transport side of the light absorbing layer. It can be said that the electron transport layer has this function as long as it is located on the electron transport side of the light absorbing layer or on the electron transport side of the light absorbing layer. In other words, the electron transport layer means a layer located on the electron transport side of the light absorbing layer or on the electron transport side of the light absorbing layer. The electron transport layer 20 preferably contains a material that easily transfers electrons generated in the perovskite compound to the transparent substrate 11. In the solar cell 100, the electron transport layer 20 may contain titanium oxide. Specifically, the electron transport layer 20 can include a dense titanium oxide layer with a relatively small porosity, a porous titanium oxide layer that is a porous layer with a higher porosity than the dense titanium oxide layer, or both a dense titanium oxide layer and a porous titanium oxide layer. The dense titanium oxide layer can be disposed on the transparent conductive film 12, and the porous titanium oxide layer can be disposed on the dense titanium oxide layer. The term "layer" does not specify thickness or width, and includes patterned or island-shaped structures and structures with varying thicknesses. The term "layer" preferably refers to a member with a substantially uniform thickness. The term "dense" refers to materials that are dense, compact, compact, etc., and includes or are equivalent to these. The term "porous" refers to materials that are porous, porous, mesoporous, etc., and includes or are equivalent to these. The term "porous" refers to materials that can contain a perovskite compound in the voids. The term "dense" refers to materials with extremely small voids. In other words, a dense material refers to materials in which the maximum void width is less than 5 nm when observed cross-sectionally by SEM. Here, the maximum width of the void refers to the maximum width of the void when observed in cross section by SEM.In the present disclosure, unless otherwise specified, SEM observation is sufficient as long as it is performed on a cross-sectional SEM image with a width of 400 nm. For example, if the maximum width of voids in a cross-sectional SEM image with a width of 400 nm is less than 5 nm, the layer can be said to be dense.

[0023] Preferably, the dense material is one that can suppress the penetration of the perovskite compound and is free of the perovskite compound on one side of the thickness direction of the dense material. More preferably, the dense material means one that cannot contain the perovskite compound in voids or one that does not have a portion where the perovskite compound is continuously present throughout the thickness of the dense material. That is, if the dense material cannot be confirmed at the maximum void width, it is sufficient that observation by SEM or EDX shows that there is no portion where the perovskite compound is present throughout the layer thickness. In the present disclosure, unless otherwise stated, SEM observation can be performed on a 400 nm wide cross-sectional SEM (or EDX) image and confirmed. For example, if there is no portion where the perovskite compound is present throughout the layer thickness in a single 400 nm wide cross-sectional SEM or EDX observation, the layer can be said to be dense. In addition, the definition of dense material as being one in which the voids are extremely small as described above takes precedence, and if this cannot be confirmed, the above preferred definition can be applied, and if this still cannot be confirmed, the above even more preferred definition can be applied.

[0024] The dense titanium oxide layer and porous titanium oxide layer that make up the electron transport layer 20 will be described below. While titanium oxide will be used as an example, the material is not limited as long as it is disposed on the electron transport side within the light absorption layer of the solar cell 100 or on the electron transport side of the light absorption layer, and it is not necessary to confirm that it naturally has the function. Examples include inorganic oxides such as zinc oxide, indium oxide, tin oxide, aluminum oxide, and gallium oxide, typically N-type inorganic oxides, and inorganic sulfides such as tin sulfide, indium sulfide, and zinc sulfide, typically N-type inorganic sulfides.

[0025] (Dense Titanium Oxide Layer) The dense titanium oxide layer has a low porosity, and therefore, during the manufacture of the solar cell 100, the perovskite compound-containing coating liquid used to form the light absorbing layer 30 does not easily penetrate into the layer. Therefore, when the solar cell 100 includes a dense titanium oxide layer, contact between the perovskite compound and the transparent conductive film 12 is suppressed. Furthermore, when the solar cell 100 includes a dense titanium oxide layer, contact between the perovskite compound and the transparent conductive film 12 can be suppressed. The film thickness of the dense titanium oxide layer is preferably 5 nm or more and 200 nm or less, and more preferably 10 nm or more and 100 nm or less. Furthermore, the filling rate in terms of mass is desirably 90% or more.

[0026] (Porous Titanium Oxide Layer) The porous titanium oxide layer has a high porosity, and therefore the perovskite compound-containing coating liquid used to form the light absorbing layer 30 during the production of the solar cell 100 can easily penetrate into the pores within the layer. Therefore, by providing the solar cell 100 with a porous titanium oxide layer, it is possible to increase the contact area between the perovskite compound, in other words, the light absorbing layer 30, and the electron transport layer 20. This allows electrons generated by photoexcitation in the perovskite compound to be efficiently transferred to the hole blocking layer 4, and holes to be blocked.

[0027] [Light Absorbing Layer] The light absorbing layer 30 is a layer capable of absorbing light. The light absorbing layer 30 is a perovskite layer containing a perovskite compound. The thickness of the light absorbing layer 30 is preferably 500 nm or more and 2 μm or less, and more preferably 700 nm or more and 800 nm or less.

[0028] The perovskite compound contained in the light-absorbing layer 30 is composed of a compound represented by the general formula: ABX3 (1). While the composition ratio of each element is preferably 1:1:3, it does not necessarily have to be 1:1:3. The content of each element may vary as appropriate, and each element does not necessarily have to be a single type. As long as the light-absorbing layer has photoelectric conversion function, the degree of freedom in the configuration described above is maintained. In general formula (1), A represents an organic molecule (including an organic group or organic cation, as defined in the present disclosure) or an inorganic atom or molecule (including an inorganic group or inorganic cation, as defined in the present disclosure) or a combination thereof; B represents a metal atom or molecule (including a metal cation, as defined in the present disclosure); and X represents a halogen atom or molecule or a chalcogen atom or molecule (including a halogen anion or chalcogen anion, as defined in the present disclosure). In general formula (1), the three Xs may be the same or different from one another. When contained in a light absorbing layer, 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 confirmed by, for example, detecting organic molecules, metal atoms, and halogen atoms. Furthermore, a perovskite compound can be confirmed by detecting elements corresponding to A, B, and X, as long as the light absorbing layer has a photoelectric conversion function. For example, molecules containing carbon, nitrogen, and hydrogen are suitable as organic molecules, and therefore, carbon, nitrogen, hydrogen, a metal element, and a halogen element or chalcogen element can be detected. Alternatively, a perovskite compound can be confirmed by detecting A, B, and X, for example, by detecting inorganic atoms, a metal atom, and a halogen atom. Furthermore, a perovskite compound can be confirmed by detecting elements corresponding to A, B, and X, as long as the light absorbing layer has a photoelectric conversion function. For example, cesium or rubidium is suitable as inorganic atoms, and therefore, cesium or rubidium, a metal element, and a halogen or chalcogen can be detected.Furthermore, the fact that the light absorbing layer 30 is a perovskite compound does not necessarily mean that it has a crystalline structure, since it is a natural consequence that the light absorbing layer must have a crystalline structure in order to have a photoelectric conversion function.The light absorbing layer 30 may include compounds other than perovskite compounds.

[0029] The light-absorbing layer 30 may contain an organic-inorganic hybrid compound. An organic-inorganic hybrid compound refers to a compound containing both inorganic and organic elements. Solar cells using perovskite compounds, which are organic-inorganic hybrid compounds, are also called organic-inorganic hybrid solar cells. "Organic" typically refers to a material composed of multiple carbon atoms. Note that graphite, graphene, carbon nanowires, carbon nanofibers, carbon nanotubes, and carbon materials such as carbon and carbon black that function as electrodes are not considered organic. In other words, organic refers to materials that contain multiple carbon atoms as one of their constituent elements, excluding carbon materials such as graphite. "Inorganic" refers to materials that are not organic. In other words, organic-inorganic hybrid compounds include materials that contain multiple carbon atoms as one of their constituent elements, but also materials that do not contain multiple carbon atoms as constituent elements, such as metal atoms, halogen atoms, or chalcogen atoms.

[0030] In general formula (1), examples of the organic molecule represented by A include alkylamine, alkylammonium, and nitrogen-containing heterocyclic compounds. In the perovskite compound (1), the organic molecule represented by A may be only one type of organic molecule, or may be two or more types of organic molecules.

[0031] 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.

[0032] Alkylammonium is an ionized product of the above-mentioned alkylamine. Examples of alkylammonium include methylammonium (CH ３ NH ３ ), 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.

[0033] 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. As the ionized nitrogen-containing heterocyclic compound, phenethylammonium is preferred.

[0034] 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.

[0035] 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.

[0036] In general formula (1), examples of halogen atoms represented by X include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms, and examples of chalcogen atoms include oxygen atoms, sulfur atoms, selenium atoms, and tellurium atoms. In the perovskite compound, the halogen atoms or chalcogen atoms represented by X may be one type or two or more types. As the halogen atom represented by X, an iodine atom is preferred from the viewpoint of enabling the perovskite compound to utilize light in a wide wavelength range. Specifically, of the three Xs, it is preferred that at least one X represents an iodine atom, and it is more preferred that all three Xs represent iodine atoms.

[0037] The perovskite compound may be a compound represented by the general formula "CH ３ NH ３ PbX ３ (wherein X represents a halogen atom)" is preferred, and ３ NH３ PbI ３ As the perovskite compound, the general formula "CH ３ NH ３ PbX ３ " (particularly, compounds represented by CH ３ NH ３ PbI ３ By using the above-mentioned compound, electrons and holes can be generated more efficiently in the perovskite compound, and as a result, the photoelectric conversion efficiency of the solar cell 100 can be further improved.

[0038] The perovskite layer includes a perovskite material having a valence band maximum level in the range of -5.1 eV to -5.7 eV and a conduction band minimum level in the range of -3.5 eV to -4.0 eV. Hereinafter, the valence band maximum will be referred to as the VBM, and the conduction band minimum will be referred to as the CBM. Furthermore, the absolute value of the difference between the vacuum level and the CBM can be rephrased as the electron affinity (or its absolute value), and the absolute value of the difference between the vacuum level and the VBM can be rephrased as the ionization potential (or its absolute value). Regarding the CBM and VBM, "deep" means "the corresponding electron affinity or ionization energy is large or far from the vacuum level," and "shallow" means "the corresponding electron affinity or ionization energy is small or close to the vacuum level."

[0039] [Hybrid Hole Transport Layer] The hybrid hole transport layer 40 is a hole transport layer that transports holes generated in the light absorbing layer 30. It is preferable that the hybrid hole transport layer 40 also block electrons generated in the light absorbing layer 30. As long as the solar cell 100 has a photoelectric conversion function, the layer disposed on the hole transport side of the light absorbing layer or on the hole transport side of the light absorbing layer naturally has a hole transport function. As long as the solar cell 100 has a photoelectric conversion function, the layer disposed on the hole transport side of the light absorbing layer or on the hole transport side of the light absorbing layer is not required to be confirmed as long as the solar cell 100 has a photoelectric conversion function. In other words, as long as the solar cell 100 has a photoelectric conversion function, the layer disposed on the hole transport side of the light absorbing layer or on the hole transport side of the light absorbing layer is considered to be a hole transport layer. The material constituting the hybrid hole transport layer 40 is preferably a material whose CBM energy level (Eebc) is greater than or equal to Eopc + 0.5 eV, relative to the CBM energy level (Eopc) of the perovskite compound.

[0040] 1, the hybrid hole transport layer 40 is characterized by including an organic material 41 and an inorganic material 42. Here, the term "hybrid" refers to a material including an organic material and an inorganic material.

[0041] The particles of the inorganic material 42 are generally denser and have a higher density than the particles of the organic material 41. Therefore, as shown in Fig. 2, it is possible to prevent moisture, oxygen, and the like from penetrating into the light absorption layer 30 from the electrode 50 side, thereby improving the conversion efficiency and durability.

[0042] The organic material 41 preferably contains an organic P-type material. This increases hole extraction efficiency, improves FF characteristics, and suppresses recombination. This also reduces the risk of moisture intrusion, improving the conversion efficiency and durability of the solar cell 100.

[0043] The organic P-type material is P ３ HT, Spiro (spiro compounds, e.g., spiro-OMeTAD (N 2 ,N 2 ,N 2 ′,N 2 ′,N 7 ,N 7 ,N 7′,N 7 '-octakis(4-methoxyphenyl)-9,9'-spirobi[9H-fluorene]-2,2',7,7'-tetramine), Spiro-MeOTAD, etc.), PTAA (poly[bis(4-phenyl)(2,4,6-triphenylmethyl)amine]), Pentacene (chemical formula: C 22 H 14 In this way, a protective layer is formed on the light absorbing layer 30 simultaneously with the formation of the hole transport layer, the risk of moisture penetration can be further reduced, and the conversion efficiency and durability of the solar cell 100 can be improved.

[0044] The inorganic material 42 preferably contains inorganic oxide P-type particles. This increases hole extraction efficiency, improves FF characteristics, and suppresses recombination. This also reduces the risk of moisture intrusion, improving the conversion efficiency and durability of the solar cell 100.

[0045] FIG. 3 shows the energy levels in the inorganic 42 layer and the organic 41 layer of the light absorbing layer 30 and the hybrid hole transport layer 40. In the solar cell 100, the recombination effect of electrons and holes is one of the causes of a decrease in the open-circuit voltage of the device. Suppressing the recombination effect improves the open-circuit voltage and device performance. The solar cell 100 according to the present disclosure includes an organic P-type material and inorganic oxide P-type particles, which, as shown in FIG. 3 , shifts the energy levels, forming smoother levels than conventional organic films and improving hole transport efficiency. Specifically, as shown in FIG. 3 , the light absorbing layer 30 (PVK) first absorbs light energy and generates electrons and holes. Furthermore, when the hole energy level shifts from -5.5 to -5.3 (moving from PVK to Spiro), light energy is absorbed and holes are transported. When moving from -5.5 to -5.38 (moving from PVK to NiO), the energy absorbed by the light absorbing layer 30 (PVK) is lower than the energy consumed when moving from -5.5 to -5.3. Therefore, more holes are transferred, and more holes flow to the inorganic 42 (Spiro) layer of the hybrid hole transport layer 40. Therefore, the energy level is smoothed.

[0046] The inorganic oxide P-type particles are NiO Ｘ , Cu ２ O, MoO Ｘ (where X is a coefficient of 1 or more). In this way, a protective layer is formed on the light absorbing layer 30 simultaneously with the formation of the hole transport layer, which further reduces the risk of moisture penetration and improves the conversion efficiency and durability of the solar cell 100.

[0047] 4 is an explanatory diagram of the conduction band level and the valence band level. As shown in FIG. 4, the inorganic oxide P-type particles preferably have a conduction band level that is the same as or shallower than that of the light absorbing layer 30, and a valence band level that is the same as or shallower than that of the light absorbing layer 30. In this way, the valence band energy levels of the inorganic material 42 layer of the hybrid hole transport layer 40 and the light absorbing layer 30 are smoothly joined, thereby improving the hole extraction efficiency. Furthermore, the inorganic material 42 layer of the hybrid hole transport layer 40 has a conduction band level shallower than that of the light absorbing layer 30, thereby improving the electron transport efficiency.

[0048] As shown in Figure 4, the organic P-type material preferably has a valence band level that is the same as or shallower than that of the inorganic oxide P-type particles. This allows the valence band energy levels of the inorganic hole transport layer and the organic hole transport layer to be smoothly connected, improving the hole extraction efficiency. Furthermore, the organic hole transport layer has a conduction band level that is shallower than that of the inorganic hole transport layer, thereby improving the electron transport efficiency.

[0049] The thickness of the hybrid hole transport layer 40 is preferably 250 to 300 nm. If the thickness of the hybrid hole transport layer 40 is less than 250 nm, the risk of moisture penetration may increase. On the other hand, if the thickness is greater than 300 nm, the risk of moisture penetration decreases, but the electrical resistance may increase.

[0050] It is also preferable that the organic material 41 contains an organic P-type material and the inorganic material 42 contains inorganic oxide P-type particles. In this way, a protective layer is formed on the light absorbing layer 30 at the same time as the hole transport layer is formed, which further reduces the risk of moisture penetration and improves the conversion efficiency and durability of the solar cell 100.

[0051] As shown in Figures 1 and 2, the hybrid hole transport layer 40 preferably has an inorganic material 42 formed on the lower part thereof, which is on the light absorption layer 30 side. In this way, electrons generated in the perovskite compound can be efficiently blocked. The inorganic material 42 of the hybrid hole transport layer 40 has a higher density than the organic material 41. The density of the organic material 41 of the hybrid hole transport layer 40 is 0.80 to 1.6 g / cm. ３ For example, if the organic matter 41 is P ３ For HT, the density is 1.02 g / cm ３ When the organic material 41 is Spiro, the density is 1.4 g / cm ３ On the other hand, the density of the inorganic material 42 of the hybrid hole transport layer 40 is 4.00 to 8.00 g / cm ３ For example, when the inorganic material 42 is NiO, the density is 6.67 g / cm ３ is.

[0052] As shown in FIGS. 1 and 2, the inorganic material 42 of the hybrid hole transport layer 40 may be unevenly distributed in the organic material 41 .

[0053] As shown in Figures 1 and 2, an inorganic layer is preferably formed near the bottom end of the hybrid hole transport layer. Furthermore, the amount of inorganic material near the top end of the hybrid hole transport layer is preferably less than that near the bottom end. Furthermore, it is preferable that no inorganic material is provided near the top end of the hybrid hole transport layer. Here, "near" refers to a range of 20 nm. Furthermore, "no inorganic material is provided" can be determined as "no inorganic material is provided" if no inorganic material is observed within a 200 nm wide range in a direction perpendicular to the stacking direction when a cross-section is observed using a device such as energy dispersive X-ray spectroscopy (SEM-EDX).

[0054] Furthermore, the thickness of the inorganic material 42 is preferably 50 to 100 nm. If the thickness of the inorganic material 42 is less than 50 nm, the risk of moisture intrusion may increase. On the other hand, if the thickness is greater than 100 nm, the risk of moisture intrusion decreases, but the thickness of the entire cell increases, which may result in an increase in electrical resistance or a decrease in charge conductivity.

[0055] Furthermore, the particle size of the inorganic substance 42 is preferably 10 to 50 nm. Here, the average particle size of the inorganic substance 42 is defined as the average particle size of either 20 adjacent particles or as many particles as possible that can be observed in a cross-sectional image of a width of 400 nm obtained by cross-sectional observation, whichever is smaller. Furthermore, the particle size can be defined as the diameter of a circle having an area equivalent to the cross-sectional area of ​​the inorganic substance in the cross-sectional image. Inorganic substances 42 with particle sizes less than 50 nm are expensive and therefore increase costs. Furthermore, inorganic substances 42 with particle sizes less than 50 nm may be at a greater risk of moisture intrusion. On the other hand, inorganic substances 42 with particle sizes greater than 50 nm are difficult to fabricate with a thickness of 50 to 100 nm, which is the preferred thickness of the inorganic substance 42 described above.

[0056] The inorganic material 42 preferably contains P-type inorganic oxide particles with a close-packed structure, which makes the crystals of the inorganic material 42 denser, reduces the risk of moisture intrusion, and improves the conversion efficiency and durability of the solar cell 100.

[0057] [Electrode] The electrode 50 is either a counter electrode on the non-light-receiving side of the solar cell 100 or on the side opposite the light-receiving side, or a transparent electrode on the light-receiving side, which is also a light-receiving surface that is transparent to incident light like a transparent conductive film. When used as a counter electrode, it is preferable that it has a function of reflecting light as a reflective electrode, but it does not necessarily have to have a reflective function. Examples of materials that constitute the electrode 50 include metals, transparent conductive inorganic materials, conductive fine particles, and conductive polymers (particularly transparent conductive polymers). Examples of metals include nickel, gold, silver, and platinum. Examples of transparent conductive inorganic materials include copper iodide (CuI), indium tin oxide (ITO), and tin oxide (SnO ２Examples of conductive fine particles include silver nanowires and carbon nanofibers. Examples of transparent conductive polymers include a polymer (PEDOT / PSS) containing poly(3,4-ethylenedioxythiophene) and polystyrene sulfonic acid. The electrode 50 may also be made of a carbon material such as graphite. While it is desirable to provide an electrode and a hole transport layer or an electron transport layer, it is not necessary for all of them to be provided. As long as the solar cell 100 has a photoelectric conversion function, it is acceptable for one of them to be omitted.

[0058] In order to efficiently apply a built-in potential to the light absorption layer 30, it is desirable that the material of the electrode 50 be a metal having a work function Φ≧5.0 eV. This results in a structure in which electrons are extracted from the transparent conductive film 12 on the transparent substrate 11 side and holes are extracted from the electrode 50 side, and a smooth flow of holes can be achieved at the interface between the hybrid hole transport layer 40 on the hole extraction side and the electrode 50, resulting in a highly efficient solar cell 100.

[0059] As described above, the solar cell 100 according to the present disclosure can improve conversion efficiency and durability.

[0060] 2. Solar Cell Module Fig. 5 is a schematic cross-sectional view of a solar cell module 1000 (series-connected solar cells) including solar cell 100 according to the present disclosure. As shown in Fig. 5, solar cell module 1000 according to the present disclosure is produced by integrating solar cell 100 described above.

[0061] 5 , a solar cell module 1000 according to the present disclosure includes a transparent substrate 11, a transparent conductive film 12 provided on the transparent substrate 11, an electron transport layer 20 provided on the transparent conductive film 12, a light absorbing layer 30 provided on the electron transport layer 20, a hybrid hole transport layer 40 provided on the light absorbing layer 30, an electrode 50 provided on the hybrid hole transport layer 40, a second barrier layer 62 provided on the electrode 50, and a back substrate 64 provided on the second barrier layer 62. The solar cell module 1000 shown in FIG. 5 is a solar cell module 1000 in which the transparent substrate 11 is transparent glass.

[0062] Fig. 6 is a schematic cross-sectional view of a solar cell module 1100 including a solar cell 100 (variant) according to the present disclosure, in which the transparent substrate 11 is a transparent resin such as an organic film. As shown in Fig. 6, the solar cell module 1100 according to the present disclosure includes the transparent substrate 11, a first barrier layer 61 provided on the transparent substrate 11, a transparent conductive film 12 provided on the first barrier layer 61, an electron transport layer 20 provided on the transparent conductive film 12, a light absorbing layer 30 provided on the electron transport layer 20, a hybrid hole transport layer 40 provided on the light absorbing layer 30, an electrode 50 provided on the hybrid hole transport layer 40, a second barrier layer 62 provided on the electrode 50, a third barrier layer 63 provided on the second barrier layer 62, and a back substrate 64 provided on the third barrier layer 63. The first barrier layer 61 is a layer of a material with high gas barrier properties. The second barrier layer 62 is a dense inorganic material layer. The third barrier layer 63 is a layer made of a material with high gas barrier properties.

[0063] 6 , the second barrier layer 62 is provided so as to cover the sides of the hybrid hole transport layer 40 and the electrode 50, and to cover the top of the electrode 50. The second barrier layer 62 covers the top and side surfaces of each solar cell 100.

[0064] 5 and 6 , the hybrid hole transport layer 40 covers the top and sides of the light absorption layer 30. The electrode 50 covers the top and one side of the hybrid hole transport layer 40. The electrode 50 extends from the top to the side of the hybrid hole transport layer 40 and connects to the top of the transparent conductive film 12 of an adjacent solar cell 100, thereby connecting the adjacent solar cell 100 in series.

[0065] The solar cell modules 1000, 1100 of the present disclosure include a plurality of solar cells 100, a first terminal 71, and a second terminal 72. The plurality of solar cells 100 are connected in series, and the solar cell 100 at one end of the plurality of solar cells 100 connected in series is connected to the first terminal 71, and the solar cell 100 at the other end is connected to the second terminal 72. There is no particular limitation on the number of solar cells 100 connected in series, as long as there is more than one.

[0066] The transparent substrate 11 is the substrate of the solar cell modules 1000 and 1100. The transparent substrate 11 may be a glass substrate as shown in Fig. 5 or a transparent organic film as shown in Fig. 6. This allows light to enter the interior of the solar cell 100. When the transparent substrate 11 is a flexible organic film, the solar cell module 1100 becomes a flexible solar cell module.

[0067] Specific examples of materials for the organic film that will become the transparent substrate 11 include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), polyetherimide (PEI), polytetrafluoroethylene (PTFE), polyamideimide (PAI), and polyethylene naphthalate (PEN), but other resins can also be used as long as they satisfy the requirements. The thickness of the organic film that will become the transparent substrate 11 is preferably 50 to 100 μm.

[0068] When the transparent substrate 11 is a transparent organic film, a first barrier layer 61 may be provided on one of the +Y-direction major surfaces of the transparent substrate 11. The first barrier layer 61 is a layer made of a material with high gas barrier properties. This prevents internal deterioration of the solar cell 100 due to moisture and oxygen in the air. The first barrier layer 61 is also a layer made of an insulating material. This prevents leakage current. The film thickness of the first barrier layer 61 can be several tens to 100 nm. This allows the first barrier layer 61 to have light-transmitting properties. Furthermore, the solar cell 100 and the solar cell module 1100 can have flexibility. Specific examples of materials for the first barrier layer 61 include silicon oxide and aluminum oxide. As long as the first barrier layer 61 has gas barrier properties, insulating properties, and light-transmitting properties, other oxides and insulators can also be used as the material for the first barrier layer 61. Main methods for forming the first barrier layer 61 include sputtering and vacuum deposition.

[0069] The transparent conductive film 12 is provided on the transparent substrate 11 (or on the first barrier layer 61) and is an electrode 50 for extracting a current generated by the photovoltaic power of the solar cell 100. The transparent conductive film 12 is made of a conductive transparent material such as aluminum-doped zinc oxide (AZO), indium zinc oxide (IZO), gallium-doped zinc oxide (GZO), fluorine-doped tin oxide (FTO), or indium tin oxide (ITO). The sheet resistance of the transparent conductive film 12 is preferably 10 Ω / sq or less, and the light transmittance of the transparent conductive film 12 is preferably 30% or more. Methods for forming the transparent conductive film 12 include sputtering and vacuum deposition.

[0070] When a plurality of solar cells 100 are provided on the transparent substrate 11, the transparent conductive film 12 formed on the transparent substrate 11 is divided for each solar cell 100. For example, the solar cell modules 1000 and 1100 shown in FIGS. 5 and 6 include five solar cells 100, and therefore the transparent conductive film 12 is divided into five transparent conductive films 12. The groove O separating two adjacent transparent conductive films 12 may be filled with a light absorbing layer 30 or the like. The transparent conductive film 12 spans two solar cells 100. That is, as shown in FIGS. 5 and 6, an electron transport layer 20 is formed on one transparent conductive film 12, and a light absorbing layer 30 is formed on the other transparent conductive film 12.

[0071] The transparent substrate 11 is formed with a first terminal 71 of the solar cell module 1000, 1100, with a portion of the first terminal 71 penetrating the transparent substrate 11 (and the first barrier layer 61) and in contact with or electrically connected to the transparent conductive film 12 of the solar cell 100 connected in series. This first terminal 71 can be used to extract current generated by the photovoltaic power of the solar cell module 1000, 1100. Examples of materials for the first terminal 71 include SnZn-based solder paste. Other conductive pastes and electrode 50 materials can also be used as long as they meet the requirements.

[0072] For example, a porous titanium oxide layer of TiO is formed on the transparent conductive film 12 as a seed layer to be the electron transport layer 20. ２ The surface of the TiO ２ A TiN (NaCl structure) layer with a thickness of 5 to 30 nm is formed on the surface of TiO ２ The lattice constants of TiN (rutile structure) and TiO (NaCl structure) are relatively well matched. ２ TiO ２ A good interface with few defects is formed between the TiN layer and the TiN layer. ２ The formation of -xNx allows the lattice constant to change continuously, suppressing the occurrence of interface defects. When the TiN layer is exposed to the atmosphere after surface modification treatment using nitrogen plasma, a re-oxidation layer of several nanometers thick is formed on the surface. ２Since the layer is thin, structural relaxation of the lattice constant does not occur, and the lattice constant of the underlying TiN layer is maintained.

[0073] After the transparent conductive film 12 is formed on the transparent substrate 11, incisions (L1) are made in the transparent conductive film 12 by laser scribing in order to separate and form the solar cell 100 on the transparent substrate 11. The wavelength of the laser used is preferably in the infrared region. The incisions (L1) are made in the transparent conductive film 12, and the transparent conductive film 12 having the incisions is formed. No incisions are made in the transparent substrate 11 or the first barrier layer 61. For example, a perovskite compound can be formed on the transparent substrate 11 and the transparent conductive film 12 in which the incisions (L1) have been made by laser scribing, to form the light absorbing layer 30.

[0074] Perovskite compounds have a tetragonal basic unit cell, which, as mentioned above, has an organic molecule or organic-inorganic mixed molecule A located at each vertex, a metal atom B located at the body center, and a halogen atom X located at each face center, and is represented by the general formula ABX ３ It is composed of crystals.

[0075] Examples of organic solvents (contained in the coating liquid) used in the coating method for forming the light absorbing layer 30 include aromatic hydrocarbons such as toluene, xylene, mesitylene, tetralin, diphenylmethane, dimethoxybenzene, and dichlorobenzene; halogenated hydrocarbons such as dichloromethane, dichloroethane, and tetrachloropropane; ethers such as tetrahydrofuran (THF), dioxane, dibenzyl ether, dimethoxymethyl ether, and 1,2-dimethoxyethane; ketones such as methyl ethyl ketone, cyclohexanone, acetophenone, and isophorone; esters such as methyl benzoate, ethyl acetate, and butyl acetate; sulfur-containing solvents such as diphenyl sulfide; fluorine-based solvents such as hexafluoroisopropanol; aprotic polar solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide; alcohols such as methanol, ethanol, and isopropanol; and glyme-based solvents such as ethylene glycol and diethylene glycol monomethyl ether. These can be used alone or as a mixed solvent. These solvents may contain water. Among these solvents, non-halogen organic solvents are preferably used in consideration of the global environment.

[0076] In addition, the coating liquid may contain additives such as an antioxidant, a viscoelasticity modifier, a preservative, a curing catalyst, etc. The coating method is not particularly limited, but preferred methods include, for example, a dip coating method, a spray coating method, and a slide hopper coating method.

[0077] After the light absorbing layer 30 is formed, a cut (L2) is made in a part of the light absorbing layer 30 by laser scribing in order to connect the transparent conductive film 12 of one of the two adjacent solar cell 100 to the hybrid hole transport layer 40 and electrode 50 of the other solar cell 100. The wavelength of the laser used is preferably in the visible light region. For example, the cut (L2) is made in the light absorbing layer 30, and the light absorbing layer 30 is formed. This laser scribing removes the light absorbing layer 30, but does not remove the transparent conductive film 12 (and the first barrier layer 61).

[0078] Thereafter, a hybrid hole transport layer is formed, and an electrode is formed.

[0079] The electrode 50 is provided on the light absorbing layer 30 and is intended to extract current generated by the photovoltaic power of the light absorbing layer 30 of the solar cell 100. The electrode 50 is, for example, a metal film with a work function of 5 eV or more. When the electrode 50 is made of a metal with a deep work function (5 eV or more), a bending of the band structure occurs at the interface between the light absorbing layer 30 and the electrode 50, which allows for a smooth flow of holes. Examples of materials for the electrode 50 include metals such as Ni, Pt, and Pd. The film thickness of the electrode 50 is preferably 50 nm to 150 nm. The light absorbing layer 30 or the electrode 50 can be formed by a sputtering method, a vacuum deposition method, or the like.

[0080] After the electrode 50 is formed, a cut (L3) is made in a portion of the hybrid hole transport layer 40 and the electrode 50 by laser scribing in order to form a series connection circuit of adjacent solar cell 100 on the transparent substrate 11. Also, in order to make the second barrier layer 62 function as a varistor, cuts may be made in the electron transport layer 20, the light absorption layer 30, the hybrid hole transport layer 40, and the electrode 50. The wavelength of the laser used is preferably in the ultraviolet region. For example, the cut (L3) is made in the hybrid hole transport layer 40 and the electrode 50, and the hybrid hole transport layer 40 and the electrode 50 are formed. Also, a cut for forming a varistor can be made. If the portion with the cut (L3) functions as a varistor, the cut can be omitted.

[0081] The second barrier layer 62 is a dense inorganic material layer and is provided so as to cover the side portions of the light absorbing layer 30. The second barrier layer 62 can also be provided so as to cover the entire periphery of the light absorbing layer 30. The second barrier layer 62 can also be provided so as to cover the upper surface of the electrode 50. This second barrier layer 62 can prevent moisture (such as water vapor) from penetrating the light absorbing layer 30, thereby preventing deterioration of the solar cell 100. Furthermore, because the second barrier layer 62 is a dense inorganic material layer, it is possible to prevent the barrier function of the second barrier layer 62 from being reduced by ultraviolet rays, temperature changes, and the like. Furthermore, the barrier properties against water vapor can also be improved by completely coating the light absorbing layer 30 with the second barrier layer 62, the transparent conductive film 12, the transparent substrate 11, and the like.

[0082] The second barrier layer 62 may also be made of a material that exhibits varistor characteristics. The second barrier layer 62 can be provided so as to connect to the transparent conductive film 12 and the electrode 50 so that the second barrier layer 62 and the light absorbing layer 30 are connected in parallel. The varistor characteristics are voltage-current characteristics (current nonlinearity) in which current suddenly begins to flow at a certain constant voltage. There are no particular restrictions on the material that exhibits varistor characteristics, as long as it is a material that can be used in a varistor element.

[0083] The thickness of the second barrier layer 62 can be, for example, 30 nm or more and 100 nm or less. The second barrier layer 62 is formed on the electrode 50 after laser scribing. The second barrier layer 62 can be formed so as to fill the notch (L3). This allows the periphery and upper surface of the light absorbing layer 30 to be covered with the second barrier layer 62. The second barrier layer 62 can be formed so as to fill the notch. This allows the second barrier layer 62 to be connected to the transparent conductive film 12 and the electrode 50 so that the second barrier layer 62 and the light absorbing layer 30 are connected in parallel.

[0084] By connecting a part of the second barrier layer 62 in parallel to the light absorbing layer 30 as a varistor element structure, it is possible to realize a solar cell 100 that is integrally provided with a bypass diode (varistor of the second barrier layer 62). This makes it possible to prevent a decrease in power generation efficiency due to shadowing on the module at low cost.

[0085] The second barrier layer 62 may contain, for example, zinc oxide (ZnO) as a main material, and may contain, as additive materials, silicon oxide, aluminum oxide, titanium oxide, etc. The varistor characteristics (I=KVα, K: element-specific constant, α: voltage nonlinearity coefficient) of the second barrier layer 62 between the transparent conductive film 12 and the electrode 50 are preferably such that α=20 to 60 and the bending voltage is 2 V or higher.

[0086] The rear substrate 64 is a substrate disposed on top of the second barrier layer 62, and the light absorbing layer 30 is located between the transparent base 11 and the rear substrate 64. The rear substrate 64 may be a substrate of the solar cell module 1000 or 1100. The rear substrate 64 may be a glass substrate, a transparent organic film, or an opaque organic film.

[0087] When the rear substrate 64 is an organic film, a third barrier layer 63 may be provided on one of the main surfaces of the rear substrate 64. The third barrier layer 63 is a layer made of a material with high gas barrier properties. This makes it possible to prevent deterioration inside the solar cell 100 due to moisture, oxygen, and the like in the air. The third barrier layer 63 is also a layer made of an insulating material. This makes it possible to suppress the flow of leakage current. The film thickness of the third barrier layer 63 can be several tens to 100 nm. Specific examples of materials for the third barrier layer 63 include silicon oxide and aluminum oxide.

[0088] A second terminal 72 of the solar cell module 1000, 1100 is formed on the organic film that serves as the rear substrate 64, and a portion of the second terminal 72 penetrates the organic film (rear substrate 64) and the third barrier layer 63, and is in contact with the electrode 50 at the end of the series-connected solar cell 100 or is connected via the second barrier layer 62. The first terminal 71 and the second terminal 72 can be used to extract current generated by photovoltaic power from the solar cell module 1000, 1100. Examples of materials for the second terminal 72 include SnZn-based solder paste. Other conductive pastes and electrode 50 materials can also be used as long as they meet the requirements.

[0089] After forming the second barrier layer 62 on the electrode 50, etc., a back substrate 64 on which a second terminal 72 is formed is attached to the second barrier layer 62 via a laminate sheet, followed by heat lamination to complete a solar cell module 1000 in which multiple solar cells 100 are connected in series. Holes are drilled in the laminate sheet sandwiched between the second barrier layer 62 and the back substrate 64 at the locations where the second terminals 72 will be located. This ensures good connection between the second terminals 72 and the second barrier layer 62 during lamination. This forms a varistor between the electrode 50 and the second terminal 72. Because a high voltage is applied between the electrode 50 and the second terminal 72 during power generation, the varistor characteristics do not interfere with current extraction. The electrode 50 and the second terminal 72 may also be in contact.

[0090] The laminate sheet may be a general laminate material, and is preferably a resin film that has high waterproof properties and can be laminated at a temperature of 130° C. or less.

[0091] Fig. 7 is a diagram in which a schematic cross-sectional view of one solar cell 100 included in the solar cell modules 1000, 1100 is superimposed with an equivalent circuit of the solar cell 100, and Fig. 8 is an equivalent circuit of the solar cell module 1000. As shown in Figs. 7 and 8, the electron transport layer 20, the light absorption layer 30, and the hybrid hole transport layer 40 can be represented by a current source 82 and a diode 83. In addition, the varistor 81 is connected to the transparent conductive film 12 and the electrode 50 so as to be connected in parallel with the light absorption layer 30.

[0092] 3. Method for Manufacturing Solar Cell Fig. 9 is a process diagram of a method for manufacturing a solar cell according to the present disclosure. As shown in Fig. 9, the method for manufacturing a solar cell according to the present disclosure includes the steps of: forming an electron transport layer on a transparent conductive substrate (S1); forming a light absorbing layer including a perovskite layer on the electron transport layer (S2); forming a hybrid hole transport layer on the light absorbing layer (S3); and forming an electrode on the hybrid hole transport layer (S4).

[0093] First, an electron transport layer is formed on a transparent conductive substrate (S1). The transparent conductive substrate and electron transport layer used are as described above. For example, fluorine-doped SnO ２ A solution for an electron transport layer (coating liquid) is prepared and applied to a glass substrate on which a conductive film has been vapor-deposited by a spin coating method. The applied layer is then heated at 150°C for 30 minutes to form an electron transport layer on the transparent conductive substrate.

[0094] Then, a light absorbing layer including a perovskite layer is formed on the electron transport layer (S2). Fig. 10 is an explanatory diagram of a manufacturing method for forming a light absorbing layer by applying and drying a perovskite compound solution. The light absorbing layer forming step (S2) in the manufacturing method for a solar cell further includes a step of applying a coating liquid including a perovskite compound on the electron transport layer provided on a transparent substrate, and a drying step of drying the coating film thus formed.

[0095] A coating film is formed by applying the coating liquid onto the electron transport layer. The coating method is not particularly limited, but can be screen printing, dip coating, inkjet printing, slit die coating, or the like. The coating environment is preferably maintained in a low-humidity environment, and may be sealed with an inert gas such as nitrogen gas. A laminate of a transparent substrate, a transparent conductive film, and an electron transport layer may be arranged so that the transparent substrate is located on the ground side (-Y) and the electron transport layer is located on the top side (+Y), and the coating liquid is applied onto the electron transport layer from the top side of the laminate. This prevents dripping from the slit die. Furthermore, the coffee ring effect can be suppressed during the drying step.

[0096] In the drying process, the solvent contained in the coating film evaporates, which increases the concentration of the perovskite compound in the coating film and promotes crystallization of the perovskite compound from the electron transport layer side.

[0097] Next, a hybrid hole transport layer is formed on the light absorbing layer (S3). The coating method for forming the hybrid hole transport layer on the light absorbing layer is not particularly limited, but examples thereof include dip coating, spray coating, and slide hopper coating. The organic solvent (contained in the coating liquid) used in the coating method for forming the hybrid hole transport layer is chlorobenzene, dichlorobenzene, or the like.

[0098] In the step of forming the hybrid hole transport layer, a solution containing an inorganic substance is added to a solution containing an organic substance, and the inorganic substance is a hole transport material (Spiro, P ３ The inorganic material is dispersed in the coating liquid (such as HT). The weight ratio of the inorganic material is preferably 5 to 20 wt %. The coating liquid may also contain additives such as antioxidants, viscoelasticity modifiers, preservatives, and curing catalysts. The weight ratio of the inorganic material in the dried hybrid hole transport layer may be 5 to 20 wt %. Furthermore, the density of the inorganic material to be added is preferably higher than the density of the solution containing the organic material.

[0099] In the step of forming the hybrid hole transport layer, a solution containing an inorganic substance is added to a solution containing an organic substance, thereby allowing the hybrid hole transport layer to be formed in a single addition.

[0100] Then, an electrode is formed on the hybrid hole transport layer (S4). For example, a gold vapor deposition film is formed as an anode by vacuum deposition, thereby obtaining a solar cell according to the present disclosure. The electrode used is as described above.

[0101] As described above, according to the solar cell manufacturing method of the present disclosure, a solution containing an inorganic substance is added to a solution containing an organic substance, so that a hybrid hole transport layer can be formed in a single process. This makes it possible to easily manufacture solar cells with improved conversion efficiency and durability, and to simplify conventional processes.

[0102] The solar cell and the method for manufacturing the solar cell according to the present disclosure will be specifically explained below using examples and comparative examples, but the present invention is not limited to the examples described here.

[0103] (Example 1) (1) Transparent conductive substrate: Fluorine-doped SnO ２ A glass substrate (thickness: X mm) on which a conductive film is vapor-deposited is prepared and cut into a size of 25 mm x 25 mm. The substrate is subjected to ultrasonic cleaning with ethanol for 15 minutes, dried with nitrogen gas, and then irradiated with UV light for 30 minutes to obtain a transparent conductive substrate.

[0104] (2) Electron transport layer First, tin (IV) oxide, 15% in H ２ A 15% by mass aqueous solution of O colloidal dispersion (manufactured by Alfa Aesar) is diluted with ultrapure water to prepare a solution (coating liquid) for the electron transport layer, which is a 7.5% by mass aqueous solution of tin(IV) oxide. Next, the solution for the electron transport layer is applied by spin coating onto the first conductive layer prepared in "1. First conductive layer," and the applied layer is heated at 150°C for 30 minutes to form a tin oxide electron transport layer with a thickness of 50 to 100 nm.

[0105] (3) Light-Absorbing Layer (Perovskite Light-Absorbing Layer) First, 18.3 mg of CsI (Cesium Iodide) (manufactured by Tokyo Chemical Industry Co., Ltd.), 22.7 mg of MABr (Methylamine Hydrobromide, chemical formula: CHNHBr) (manufactured by Tokyo Chemical Industry Co., Ltd.), 25.7 mg of PbBr (manufactured by Tokyo Chemical Industry Co., Ltd.), and PbI ２ (Tokyo Chemical Industry Co., Ltd.) 596.2 mg, FAI (Formamidine Hydroiodide, chemical formula: CH ４ N ２ 187.5 mg of N,N-Dimethylformamide (H1) (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved by heating in a mixed solution of 0.8 ml of DMF (N,N-Dimethylformamide, chemical formula: C3H7NO) (manufactured by Tokyo Chemical Industry Co., Ltd.) and 0.24 ml of DMSO (manufactured by Tokyo Chemical Industry Co., Ltd.). ０．８５ MA ０．１５ PbI ２．７５ Br ０．２５A coating solution is prepared. This coating solution is applied by spin coating onto the tin oxide layer prepared in "(2) Electron transport layer," and chlorobenzene is added dropwise during the spinning process to prepare a coating film. The coating layer is heated at 150°C for 10 minutes to form a perovskite light-absorbing layer with a thickness of 500 to 1,000 nm.

[0106] (4) Hybrid hole transport layer First, 73.5 mg of Spiro-OMeTAD (Tokyo Chemical Industry Co., Ltd.), Co(III)TFSI (Tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine)-cobalt(III)tris(bis(trifluoromethylsulfonyl)imide)), chemical formula: C 42 H 45 CoF 18 N 12 O 12 S6) 13.5 mg of complex (FK209) (manufactured by Tokyo Chemical Industry Co., Ltd.), 27 μl of TBP (manufactured by Tokyo Chemical Industry Co., Ltd.), 8.6 mg of LiTSFI (Bis(trifluoromethane)-sulfonimide lithium salt, chemical formula: CF3SO2NLiSO2CF3) (manufactured by Tokyo Chemical Industry Co., Ltd.), and 14.3 mg of NiO (particle size 30 nm) (manufactured by Tokyo Chemical Industry Co., Ltd.) were heated and dissolved in 1 ml of chlorobenzene (manufactured by Tokyo Chemical Industry Co., Ltd.) to prepare a hole transport layer coating solution. This coating solution was applied by spin coating to the perovskite light absorption layer prepared in the "Light Absorption Layer (Perovskite Light Absorption Layer)" section, and the coating layer was heated at 70°C for 30 minutes to form a hybrid hole transport layer containing organic and inorganic materials with a thickness of 250 to 300 nm. The thickness of the p-type inorganic layer (inorganic material) of the light absorption layer with uneven deposition was set to 40 to 100 nm.

[0107] (5) Electrode (Anode) On the hole transport layer prepared in "(4) Hybrid hole transport layer", a gold vapor-deposited film having an area of ​​3 mm × 20 mm and a thickness of 80 nm was formed as an anode by vacuum deposition to obtain the solar cell of Example 1.

[0108] Example 2: In the hybrid hole transport layer, Cu oxide was used instead of NiO. ２ A solar cell of Example 2 is obtained in the same manner as in Example 1, except that O (particle size: 10 nm) is used.

[0109] Example 3 A solar cell of Example 3 is obtained in the same manner as in Example 1, except that the oxide MoOx (particle size 13 nm) is used in place of NiO in the hybrid hole transport layer.

[0110] Example 4 A solar cell of Example 4 is obtained in the same manner as in Example 1, except that CuO oxide (particle size: 10 nm) is used in place of NiO in the hybrid hole transport layer.

[0111] Example 5: Perovskite light absorbing layer containing FA ０．８５ MA ０．１５ PbI ２．７５ Br ０．２５ Instead of MAPbI ３ A solar cell of Example 5 is obtained in the same manner as in Example 1, except that a cation exchange resin (chemical formula: CH3NH3PbI3) was used.

[0112] Example 6: In the hybrid hole transport layer, Cu oxide was used instead of NiO. ２ A solar cell of Example 6 is obtained in the same manner as in Example 1, except that 0 (particle size 1800 nm) is used.

[0113] Example 7: In the hybrid hole transport layer, Cu oxide was used instead of NiO. ２ A solar cell of Example 7 is obtained in the same manner as in Example 1, except that 0 (particle size: 800 nm) is used.

[0114] Example 8 A solar cell of Example 8 is obtained in the same manner as in Example 1, except that ZnO oxide (particle size: 10 nm) is used in place of NiO in the hybrid hole transport layer.

[0115] Example 9 A solar cell of Example 9 is obtained in the same manner as in Example 1, except that ZnO oxide (particle size: 300 nm) is used in place of NiO in the hybrid hole transport layer.

[0116] Example 10: Perovskite light absorbing layer containing FA ０．８５ MA ０．１５ PbI ２．７５ Br ０．２５ Instead of MASn ３ I ３ A solar cell of Example 10 is obtained in the same manner as in Example 1 except that the above-mentioned was used.

[0117] Example 11: Perovskite light absorbing layer: FA0.8MA ０．１５ PbI ２．７５ Br ０．２５ Instead of MASn ０．５ Pb ０．５ I ３ A solar cell of Example 11 is obtained in the same manner as in Example 1 except that the above-mentioned was used.

[0118] Comparative Example 1 On the other hand, a solar cell of Comparative Example 1 is obtained in the same manner as in Example 1, except that NiO is not added to the hybrid hole transport layer.

[0119] The results of the above examples and comparative examples are shown in Table 1. In Table 1, Ec1 indicates the conduction band level of the perovskite layer, and Ev1 indicates the valence band level of the perovskite layer. Ec2 indicates the conduction band level of the inorganic oxide P-type particles, and Ev2 indicates the valence band level of the inorganic oxide P-type particles. Ec3 indicates the conduction band level of the organic P-type material, and Ev3 indicates the valence band level of the organic P-type material.

[0120]

[0121] As shown in Table 1, NiO and Cu ２ Solar cells in which a hybrid hole transport layer is formed using inorganic materials such as O, MoOx, CuO, and ZnO show very good or excellent results in all respects.

[0122] In particular, solar cells with inorganic particles having a diameter of 10 to 50 nm tend to show excellent results.

[0123] As a result, it is possible to provide a solar cell with improved conversion efficiency and durability, and a method for manufacturing the solar cell. Furthermore, the solar cell and the method for manufacturing the solar cell according to the present disclosure can be suitably used and applied to large-area solar power generation systems (mega solar) and power sources for small portable devices.

[0124] Although each embodiment and each example of the present disclosure have been described in detail above, it will be readily apparent to those skilled in the art that many modifications are possible without substantially departing from the novel features and effects of the present disclosure. Therefore, all such modifications are intended to be included within the scope of the present disclosure.

[0125] For example, a term described at least once in the specification or drawings together with a different term having a broader or similar meaning can be replaced with that different term anywhere in the specification or drawings. Furthermore, the configurations and operations of the solar cell and the method for manufacturing the solar cell are not limited to those described in the embodiments and examples of the present disclosure, and various modifications are possible.

Claims

1. A method for manufacturing a solar cell, comprising the steps of: forming an electron transport layer on a first electrode; forming a light absorbing layer including a perovskite layer on the electron transport layer; forming a hybrid hole transport layer on the light absorbing layer; and forming a second electrode on the hybrid hole transport layer, wherein the step of forming the hybrid hole transport layer comprises adding a solution containing an inorganic substance to a solution containing an organic substance.

2. The method for manufacturing a solar cell according to claim 1, characterized in that the density of the inorganic material to be added is higher than the density of the solution containing the organic material.

3. The method for manufacturing a solar cell according to claim 1 or 2, characterized in that the perovskite layer contains a perovskite material having a valence band upper level in the range of -5.1 eV to -5.7 eV and a conduction band lower level in the range of -3.5 eV to -4.0 eV.

4. The perovskite layer has the general formula ABX ３ 4. The method for manufacturing a solar cell according to claim 1, wherein the solar cell is made of a crystal of the formula: wherein A is an organic molecule or an organic / inorganic mixed molecule, B is a metal atom, and X is a halogen atom.

5. A method for manufacturing a solar cell according to any one of claims 1 to 4, characterized in that the hybrid hole transport layer has a thickness of 250 to 300 nm, the organic matter contains an organic P-type material, and the inorganic matter contains inorganic oxide P-type particles.

6. A method for manufacturing a solar cell according to any one of claims 1 to 5, characterized in that the inorganic layer is formed near the lower end of the hybrid hole transport layer.

7. The method for manufacturing a solar cell according to claim 6, wherein the amount of said inorganic material near the upper end of said hybrid hole transport layer is less than that near the lower end.

8. The method for manufacturing a solar cell according to claim 7, characterized in that the inorganic material is not provided near the upper end of the hybrid hole transport layer.

9. The method for manufacturing a solar cell according to claim 6, characterized in that the inorganic layer has a thickness of 50 to 100 nm, and the inorganic material contains P-type inorganic oxide particles having a close-packed structure.

10. The organic material includes an organic P-type material, ３ The method for producing a solar cell according to any one of claims 1 to 9, characterized in that the compound contains at least one selected from the group consisting of HT, Spiro, PTAA and Pentacene.

11. The inorganic material includes inorganic oxide P-type particles, and the inorganic oxide P-type particles are NiO Ｘ , Cu ２ O, M.O. Ｘ and the inorganic oxide P-type particles have a conduction band level that is the same as or shallower than the light absorbing layer, and a valence band level that is the same as or shallower than the light absorbing layer.

12. A method for manufacturing a solar cell described in any one of claims 1 to 9, characterized in that the organic matter includes an organic P-type material, the inorganic matter includes inorganic oxide P-type particles, and the organic P-type material has the same or a shallower valence band level as the inorganic oxide P-type particles.

13. A method for manufacturing a solar cell according to any one of claims 1 to 12, characterized in that the particle size of the inorganic material is 10 to 50 nm.

14. A method for manufacturing a solar cell module, comprising integrating and modularizing solar cells manufactured by the method for manufacturing a solar cell according to any one of claims 1 to 13.

15. A solar cell comprising, in this order, an electron transport layer, a light absorption layer containing a perovskite compound, and a hybrid hole transport layer, wherein the hybrid hole transport layer contains an organic material and an inorganic material.

16. The solar cell according to claim 15, wherein the perovskite compound includes a perovskite material having a valence band upper edge level in the range of -5.1 eV to -5.7 eV and a conduction band lower edge level in the range of -3.5 eV to -4.0 eV.

17. The perovskite compound has the general formula ABX ３ 17. The solar cell according to claim 15, characterized in that the solar cell is composed of a crystal of the formula: wherein A is an organic molecule or an organic / inorganic mixed molecule, B is a metal atom, and X is a halogen atom.

18. A solar cell as described in any one of claims 15 to 17, characterized in that the hybrid hole transport layer has a thickness of 250 to 300 nm, the organic material includes an organic P-type material, and the inorganic material includes inorganic oxide P-type particles.

19. A solar cell according to any one of claims 15 to 18, characterized in that the inorganic material is formed near the lower end of the hybrid hole transport layer.

20. The solar cell of claim 19, wherein the amount of said inorganic material near the top of said hybrid hole transport layer is less than that near the bottom.

21. The solar cell according to claim 20, characterized in that the inorganic material is not provided near the upper end of the hybrid hole transport layer.

22. The solar cell according to claim 19, characterized in that the inorganic material has a film thickness of 50 to 100 nm, and the inorganic material contains P-type inorganic oxide particles having a close-packed structure.

23. The organic material includes an organic P-type material, ３ 23. The solar cell according to claim 15, further comprising at least one selected from the group consisting of HT, Spiro, PTAA, and Pentacene.

24. The inorganic material includes inorganic oxide P-type particles, and the inorganic oxide P-type particles are NiO Ｘ , Cu ２ O, M.O. Ｘ The solar cell according to any one of claims 15 to 23, characterized in that the inorganic oxide P-type particles have a conduction band level that is the same as or shallower than that of the light absorbing layer, and a valence band level that is the same as or shallower than that of the light absorbing layer.

25. A solar cell described in any one of claims 15 to 22, characterized in that the organic material includes an organic P-type material, the inorganic material includes inorganic oxide P-type particles, and the organic P-type material has the same or a shallower valence band level as the inorganic oxide P-type particles.

26. A solar cell according to any one of claims 15 to 25, characterized in that the particle size of the inorganic material is 10 to 50 nm.

27. A solar cell module comprising the solar cell according to any one of claims 15 to 26 integrated and modularized, wherein the first electrode is a transparent conductive substrate.

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