Solar cell and preparation method therefor, photovoltaic module and photovoltaic device

Abstract

The present application relates to the technical field of solar cells, and discloses a solar cell and a preparation method therefor, a photovoltaic module and a photovoltaic device. The solar cell comprises a first electrode layer, a hole transport layer, a first light absorbing layer, an interconnection layer, a second light absorbing layer, an electron transport layer and a second electrode layer which are sequentially arranged in a first direction, wherein the interconnection layer comprises a SnOx layer, the SnOx layer comprises at least three SnOx materials, and in the first direction, x decreases from 2 to 1 in gradient. According to the technical solution of embodiments of the present application, the performance of the solar cell is improved.

Description

Solar cell and preparation method thereof, photovoltaic module and photovoltaic device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202310943482.3, filed on July 31, 2023, entitled “Solar cells and methods for preparing the same, photovoltaic modules and photovoltaic devices,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the technical field of solar cells, and in particular to a solar cell and a preparation method thereof, a photovoltaic module and a photovoltaic device. Background Art

[0004] In recent years, global energy shortages and environmental pollution have become increasingly prominent, and solar cells, as an ideal renewable energy source, have garnered increasing attention. Solar cells, also known as photovoltaic cells, are devices that convert light energy directly into electrical energy through the photoelectric or photochemical effects. Within a few years of their development, they have rapidly achieved high photoelectric conversion efficiencies, demonstrating promising application prospects.

[0005] With the development of solar cell technology, people have higher and higher requirements on the performance of solar cells, such as efficiency and stability of solar cells. Therefore, how to improve the performance of solar cells is a technical problem that needs to be solved urgently.

[0006] Summary of the Invention

[0007] The present application is made in view of the above-mentioned problems, and its purpose is to provide a solar cell and a preparation method thereof, a photovoltaic module and a photovoltaic device to improve the performance of the solar cell.

[0008] In a first aspect, a solar cell is provided, comprising: a first electrode layer, a hole transport layer, a first light absorption layer, an interconnection layer, a second light absorption layer, an electron transport layer, and a second electrode layer arranged in sequence along a first direction; wherein the interconnection layer comprises SnO x layer, the SnO x The layer includes at least three SnO x material, and along the first direction, x decreases gradually from 2 to 1.

[0009] The embodiment of the present application provides a solar cell, comprising a first electrode layer, a hole transport layer, a first light absorbing layer, an interconnection layer, a second light absorbing layer, an electron transport layer, and a second electrode layer arranged in sequence along a first direction. The interconnection layer is disposed between the first light absorbing layer and the second light absorbing layer, and can serve as both a carrier transport layer for the first light absorbing layer and a carrier transport layer for the second light absorbing layer, thereby simplifying the preparation process of the solar cell. Specifically, the interconnection layer comprises SnO x layer, SnO x The layer includes at least three SnO x The material is made of a silicon nitride-based material, and along the first direction, x decreases gradually from 2 to 1. In this way, the interconnection layer can effectively transmit the carriers in the first light absorption layer and the carriers in the second light absorption layer, thereby improving the efficiency of the solar cell.

[0010] In a possible implementation, the SnO x The thickness d1 of the layer satisfies: 1 nm ≤ d1 ≤ 200 nm.

[0011] In a possible implementation, the SnO x The thickness d1 of the layer satisfies: 5 nm ≤ d1 ≤ 20 nm.

[0012] SnO x Setting the thickness of the layer within the above range is beneficial to improving the efficiency of the solar cell.

[0013] In a possible implementation, the SnO x The layers include SnO2 layer, SnO y layer and SnO layer, the SnO y The SnO2 layer is located between the SnO layer and the SnO layer, and the SnO layer is located between the SnO y Between the layer and the second light-absorbing layer, y satisfies: 1<y<2.

[0014] In a possible implementation, the thickness d2 of the SnO2 layer satisfies: 1 nm ≤ d2 ≤ 50 nm.

[0015] In a possible implementation, the thickness d2 of the SnO2 layer satisfies: 5nm≤d2≤10nm.

[0016] In a possible implementation, the SnO y The thickness d3 of the layer satisfies: 1 nm ≤ d3 ≤ 50 nm.

[0017] In a possible implementation, the SnO y The thickness d3 of the layer satisfies: 2nm≤d3≤8nm.

[0018] In a possible implementation, the thickness d4 of the SnO layer satisfies: 1 nm ≤ d4 ≤ 50 nm.

[0019] In a possible implementation, the thickness d4 of the SnO layer satisfies: 5 nm ≤ d4 ≤ 20 nm.

[0020] The SnO2 layer, SnO y The SnO layer and the SnO layer are respectively set within the above ranges, which is beneficial to improving the efficiency of the solar cell.

[0021] In a possible implementation, the interconnection layer further includes a first hole blocking layer, which is located between the first light absorbing layer and the SnO x Between layers.

[0022] In a possible implementation, the solar cell further includes a second hole blocking layer, where the second hole blocking layer is located between the second light absorbing layer and the electron transport layer.

[0023] In one possible implementation, the material of the first electrode layer includes: a transparent conductive oxide, and the transparent conductive oxide includes at least one of indium tin oxide, gallium zinc oxide, lanthanide metal-doped indium oxide, fluorine-doped tin oxide, indium-doped tungsten oxide, indium-doped zinc oxide, boron-doped zinc oxide, and aluminum-doped zinc oxide.

[0024] In a possible implementation, the material of the hole transport layer includes a P-type semiconductor, and the material of the electron transport layer includes an N-type semiconductor.

[0025] In a possible implementation, the material of the hole transport layer includes at least one of the following materials and their derivatives: [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphoric acid, [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphoric acid, [4-(3,6-dibromo-9H-carbazole-9-yl)butyl]phosphoric acid, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], poly-3-hexylthiophene, triphenylamine with triptycene as the core, 3,4-ethylenedioxythiophene-methoxytriphenylamine, N-(4-phenylamino)carbazole-spirobifluorene, poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid, polythiophene, nickel oxide, molybdenum oxide, Cuprous iodide, cuprous oxide; the material of the electron transport layer includes at least one of the following materials and their derivatives: bathocuproin, [6,6]-phenyl-C61-butyric acid isomethyl ester, [6,6]-phenyl C71-butyric acid methyl ester, C60, C70, SnO z (1.5≤z≤2), zinc oxide.

[0026] In a possible implementation, the material of the first light absorption layer is perovskite, and the material of the second light absorption layer is perovskite.

[0027] Perovskite materials have the advantages of high conversion efficiency, low cost, and environmental protection. They can be prepared into very thin films and applied to solar cells, which can effectively improve the efficiency of solar cells.

[0028] In a possible implementation, the first direction is the incident direction of sunlight, and the band gap of the material of the first light absorption layer is greater than the band gap of the material of the second light absorption layer.

[0029] When the first direction is the incident direction of sunlight, sunlight first irradiates the first light absorbing layer. Setting the band gap of the material of the first light absorbing layer to be larger than the band gap of the material of the second light absorbing layer is beneficial to improving the efficiency of the solar cell.

[0030] In a possible implementation, the chemical formula of the perovskite in the first light absorbing layer and the second light absorbing layer is ABX3, wherein A includes CH3(NH2)2 + 、CH(NH2)2 + 、CH3NH2 + 、Li + 、Na + , K + , Rb + 、Cs + At least one of, B includes Pb + 、Be 2+ Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ 、Zn 2+ 、Ge 2+ 、Fe 2+ 、Co 2+ 、Ni 2+ At least one of, X includes Cl - Br - , I - 、SCN - 、CNO - 、OCN - 、OSCN - SH - OH - 、CP - 、CN - 、SeCN - 、N3 - 、NO2 - At least one of .

[0031] In a possible implementation, the second electrode layer includes a metal, and the metal includes at least one of gold, silver, copper, aluminum, nickel, chromium, bismuth, platinum, magnesium, molybdenum, tungsten, and alloys thereof.

[0032] In a possible implementation, the material of the first hole blocking layer includes fullerene and its derivatives, SnO z At least one of (1.5≤z≤2).

[0033] In a possible implementation, the material of the second hole blocking layer includes fullerene and its derivatives, SnO z At least one of (1.5≤z≤2).

[0034] In a second aspect, a method for preparing a solar cell is provided, comprising: providing a first electrode layer, a hole transport layer, a first light absorption layer, an interconnection layer, a second light absorption layer, an electron transport layer, and a second electrode layer arranged in sequence along a first direction; wherein the interconnection layer comprises SnO x layer, the SnO x The layer includes at least three SnO x material, and along the first direction, x decreases gradually from 2 to 1.

[0035] In one possible implementation, providing a first electrode layer, a hole transport layer, a first light absorption layer, an interconnection layer, a second light absorption layer, an electron transport layer, and a second electrode layer arranged in sequence along a first direction includes: providing the first electrode layer; preparing the hole transport layer on the first electrode layer; preparing the first light absorption layer on the hole transport layer; preparing the interconnection layer on the first light absorption layer; preparing the second light absorption layer on the interconnection layer; preparing the electron transport layer on the second light absorption layer; and preparing the second electrode layer on the electron transport layer.

[0036] In a possible implementation, the step of preparing the interconnection layer on the first light absorbing layer includes: preparing the SnO x layer, forming the interconnection layer.

[0037] In a possible implementation, the SnO x layer, comprising: preparing a SnO2 layer on the first light absorbing layer, and preparing a SnO y layer (1<y<2), in the SnO y A SnO layer is prepared on the layer to obtain the SnO x layer.

[0038] In a possible implementation, the SnO xlayer, comprising: depositing SnO on the first light absorbing layer using an atomic layer deposition device x (1≤x≤2) material, to obtain the SnO x layer; wherein, when depositing the SnO x materials process, adjust the SnO x The ratio of tin element to oxygen element in the material decreases gradually from 2 to 1 along the first direction.

[0039] In a possible implementation, the SnO x The thickness d1 of the layer satisfies: 1 nm ≤ d1 ≤ 200 nm.

[0040] In a possible implementation, the SnO x The thickness d1 of the layer satisfies: 5 nm ≤ d1 ≤ 20 nm.

[0041] In a possible implementation, the thickness d2 of the SnO2 layer satisfies: 1 nm ≤ d2 ≤ 50 nm.

[0042] In a possible implementation, the thickness d2 of the SnO2 layer satisfies: 5nm≤d2≤10nm.

[0043] In a possible implementation, the SnO y The thickness d3 of the layer satisfies: 1 nm ≤ d3 ≤ 50 nm.

[0044] In a possible implementation, the SnO y The thickness d3 of the layer satisfies: 2nm≤d3≤8nm.

[0045] In a possible implementation, the thickness d4 of the SnO layer satisfies: 1 nm ≤ d4 ≤ 50 nm.

[0046] In a possible implementation, the thickness d4 of the SnO layer satisfies: 5 nm ≤ d4 ≤ 20 nm.

[0047] In a third aspect, a photovoltaic assembly is provided, comprising the solar cell according to the first aspect and any possible implementation thereof, and / or the solar cell produced by the preparation method according to the second aspect and any possible implementation thereof.

[0048] In a fourth aspect, a photovoltaic device is provided, comprising the photovoltaic assembly in the third aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0050] FIG1 is a schematic diagram of a solar cell according to an embodiment of the present application;

[0051] FIG2 is a schematic diagram of a solar cell according to an embodiment of the present application;

[0052] FIG3 is a schematic diagram of a method for preparing a solar cell according to an embodiment of the present application. DETAILED DESCRIPTION

[0053] The following detailed description specifically discloses the embodiments of the solar cell and its preparation method, photovoltaic module, and photovoltaic device of the present application, with appropriate reference to the accompanying drawings. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there may be cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structure are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided to enable those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0054] " range " disclosed in the present application is limited in the form of lower limit and upper limit, and given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of special range. The scope limited in this way can be to include end value or not include end value, and can be arbitrarily combined, that is, any lower limit can form a range with any upper limit combination. For example, if the scope of 60-120 and 80-110 is listed for specific parameters, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range value 1 and 2 are listed, and if the maximum range value 3,4 and 5 are listed, then the following range can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In this application, unless otherwise specified, the numerical range " ab " represents the abbreviation of any real number combination between a and b, wherein a and b are all real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is simply an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0055] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0056] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0057] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), indicating that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0058] If there is no special explanation, the "include" and "comprising" mentioned in this application are open-ended. For example, the "include" and "comprising" may mean that other components not listed may also be included or comprised.

[0059] Unless otherwise specified, the term "and / or" is inclusive in this application. For example, the phrase "A and / or B" means "A, B, or both A and B." More specifically, the condition "A or B" is satisfied if any of the following conditions are met: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0060] Solar cells have good application prospects due to their high photoelectric conversion efficiency. In solar cells, the arrangement of each film layer is crucial to the performance of the solar cell, such as stability and efficiency. At present, in order to simplify the preparation process of solar cells and reduce the risk of solar cell performance degradation due to complex processes, an interconnection layer containing tin oxide is set between the two light-absorbing layers of the stacked cell and serves as a carrier transport layer for the two light-absorbing layers. However, the tin oxide materials currently contained in the interconnection layer are all single types of tin oxide, such as SnO 1.76 Or SnO2, this single type of tin oxide has limited ability to transport carriers between the two light-absorbing layers, which will affect the performance of solar cells.

[0061] In view of this, an embodiment of the present application provides a solar cell, which includes a first electrode layer, a hole transport layer, a first light absorption layer, an interconnection layer, a second light absorption layer, an electron transport layer, and a second electrode layer arranged in sequence along a first direction; wherein the interconnection layer includes SnO xlayer, SnO x The layer includes at least three SnO x The material is made of a silicon nitride-based material, and along the first direction, x decreases gradually from 2 to 1. In this way, the interconnection layer can effectively transmit the carriers in the first light absorption layer and the mineral carriers in the second light absorption layer, thereby improving the efficiency of the solar cell.

[0062] [Solar Cell]

[0063] Figure 1 is a schematic diagram of a solar cell according to one embodiment of the present application. As shown in Figure 1 , solar cell 10 includes a first electrode layer 11, a hole transport layer 12, a first light absorption layer 13, an interconnect layer 14, a second light absorption layer 15, an electron transport layer 16, and a second electrode layer 17, arranged sequentially along a first direction.

[0064] The first direction may be the thickness direction of the solar cell. For example, as shown in FIG1 , the first direction is the L direction (the direction indicated by the arrow).

[0065] The interconnection layer 14 includes SnO x Layer 141, SnO x Layer 141 includes at least three types of SnO x material, and along the first direction, x decreases gradually from 2 to 1.

[0066] The SnO mentioned here x The layer 141 includes at least three SnOx materials. Along the first direction, x decreases from 2 to 1, which means that SnO x Layer 141 may include at least three layers containing SnO x The film layer of the material, SnO in each film layer x The materials are different, for example, along the first direction, the first SnO x SnO in the film x The material is SnO2, the second SnO x SnO in the film x The material is SnO 1.5 , the third SnO x SnO in the film x The material is SnO 1.3 , the fourth SnO x SnO in the film x The material is SnO. x The layer 141 includes four kinds of SnOx materials for illustration, but in the technical solution of the embodiment of the present application, SnO x Layer 141 is not limited to including four SnOx materials, SnO x Layer 141 may include three types of SnO xmaterial, five SnOx materials, six SnOx materials... It should be understood that along the first direction, SnO x The SnO in each film layer included in layer 141 x Different materials, SnO in the same film layer x Same materials.

[0067] In the technical solution of the embodiment of the present application, the interconnection layer 14 includes SnO x The layer 141 includes at least three types of SnO x material, and along the first direction, x decreases gradually from 2 to 1. The interconnection layer 14 of this structure can play a good role in transmitting carriers of the first light absorption layer 13 and the second light absorption layer 15, thereby improving the efficiency of the solar cell 10.

[0068] When exposed to sunlight, the first and second light-absorbing layers 13 and 15 can generate electron-hole pairs. The materials used in the first and second light-absorbing layers 13 and 15 absorb light, such as perovskite materials. Perovskite materials have advantages such as high conversion efficiency, low cost, and environmental friendliness. They can be prepared into very thin films and applied to solar cells, effectively improving their efficiency.

[0069] The hole transport layer 12 is used to transport holes. The material of the hole transport layer 12 includes a P-type semiconductor. A P-type semiconductor, also known as a hole-type semiconductor, is a semiconductor that mainly conducts electricity through positively charged holes.

[0070] The electron transport layer 16 is used to transport electrons. The material of the electron transport layer 16 includes an N-type semiconductor. An N-type semiconductor, also known as an electron-type semiconductor, is a semiconductor that mainly conducts electricity through negatively charged electrons.

[0071] The first electrode layer 11 and the second electrode layer 17 are conductive film layers. Connecting the first electrode layer 11 and the second electrode layer 17 can generate photocurrent, thereby supplying power to the electrical device.

[0072] The solar cell 10 provided in the embodiment of the present application includes a first electrode layer 11, a hole transport layer 12, a first light absorption layer 13, an interconnection layer 14, a second light absorption layer 15, an electron transport layer 16, and a second electrode layer 17 arranged in sequence along a first direction. The interconnection layer 14 is provided between the first light absorption layer 13 and the second light absorption layer 15, and can serve as both a carrier transport layer for the first light absorption layer 13 and a carrier transport layer for the second light absorption layer 15, thereby simplifying the preparation process of the solar cell 10. Specifically, the interconnection layer 14 includes SnO x Layer 141, SnO x Layer 141 includes at least three types of SnO xThe interconnect layer 14 is a material, and along the first direction, x decreases gradually from 2 to 1. In this way, the interconnect layer 14 can effectively transmit the carriers in the first light absorption layer 13 and the carriers in the second light absorption layer 15, thereby improving the efficiency of the solar cell 10.

[0073] In some embodiments, as shown in FIG1 , SnO x The thickness d1 of the layer 141 satisfies: 1 nm≤d1≤200 nm, optionally, 5 nm≤d1≤20 nm.

[0074] Specifically, SnO x The thickness d1 of the layer 141 may be 1 nm, 10 nm, 20 nm, 50 nm, 80 nm, 100 nm, 150 nm, 180 nm, 200 nm, or a value between any two of the above values.

[0075] SnO x The thickness of the layer 141 is set within the above range, which is beneficial to improving the efficiency of the solar cell.

[0076] Optionally, in some embodiments, as shown in FIG2 , SnO x Layer 141 includes SnO2 layer 1411, SnO y layer 1412 and SnO layer 1413, SnO y The layer 1412 is located between the SnO2 layer 1411 and the SnO layer 1413. The SnO layer 1413 is located between the SnO2 layer 1411 and the SnO layer 1413. y Between the layer 1412 and the second light absorbing layer 15 , y satisfies: 1<y<2.

[0077] In some embodiments, as shown in FIG. 2 , the thickness d2 of the SnO 2 layer 1411 satisfies: 1 nm ≤ d2 ≤ 50 nm. Optionally, d2 satisfies: 5 nm ≤ d2 ≤ 10 nm.

[0078] Specifically, the thickness d2 of the SnO2 layer 1411 can be 1 nm, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, or a value between any two of the above values.

[0079] The thickness d2 of the SnO2 layer 1411 is set within the above range, which is beneficial to improving the performance of the battery.

[0080] In some embodiments, as shown in FIG2 , SnO y The thickness d3 of the layer 1412 satisfies: 1 nm ≤ d3 ≤ 50 nm. Optionally, d3 satisfies: 2 nm ≤ d3 ≤ 8 nm.

[0081] Specifically, SnO yThe thickness d3 of the layer 1412 may be 1 nm, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, or a value between any two of the above values.

[0082] In some embodiments, as shown in FIG. 2 , the thickness d4 of the SnO layer 1413 satisfies: 1 nm≤d4≤50 nm. Optionally, d4 satisfies: 5 nm≤d4≤20 nm.

[0083] Specifically, the thickness d4 of the SnO layer 1413 may be 1 nm, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, or a value between any two of the above values.

[0084] The SnO2 layer 1411, SnO y The SnO layer 1412 and the SnO layer 1413 are respectively set within the above ranges, which is beneficial to improving the efficiency of the solar cell.

[0085] In the technical solution of the embodiment of the present application, the thickness of each film layer can be measured by using a step profiler. For the specific measurement method, reference can be made to the known measurement method of the step profiler.

[0086] Optionally, in some embodiments, as shown in FIG2 , the interconnection layer 14 further includes a first hole blocking layer 142 , which is located between the first light absorbing layer 13 and the SnO x Between layers 141.

[0087] The first hole blocking layer 142 can transport electrons. The material of the first hole blocking layer 142 includes fullerene and its derivatives, SnO z For example, if z is 2, the material of the first hole blocking layer 142 may include SnO 2 .

[0088] Optionally, in some embodiments, with continued reference to FIG. 2 , the solar cell 10 further includes a second hole blocking layer 18 , and the second hole blocking layer 18 is located between the second light absorbing layer 15 and the electron transport layer 16 .

[0089] The second hole blocking layer 18 can transport electrons. The materials of the second hole blocking layer 18 include fullerene and its derivatives, SnO z For example, if z is 2, the material of the second hole blocking layer 18 may include SnO2.

[0090] In some embodiments, the material of the first electrode layer 11 includes: a transparent conductive oxide. Optionally, the transparent conductive oxide includes at least one of indium tin oxide, gallium zinc oxide, lanthanide metal-doped indium oxide, fluorine-doped tin oxide, indium-doped tungsten oxide, indium-doped zinc oxide, boron-doped zinc oxide, and aluminum-doped zinc oxide.

[0091] Optionally, the material of the hole transport layer 12 includes at least one of the following materials and their derivatives: [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphoric acid, [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphoric acid, [4-(3,6-dibromo-9H-carbazole-9-yl)butyl]phosphoric acid, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], poly-3-hexylthiophene, triphenylamine with triptycene as the core, 3,4-ethylenedioxythiophene-methoxytriphenylamine, N-(4-phenylamino)carbazole-spirobifluorene, poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid, polythiophene, nickel oxide, molybdenum oxide, cuprous iodide, and cuprous oxide.

[0092] Optionally, the material of the electron transport layer 16 includes at least one of the following materials and their derivatives: bathocuproine, [6,6]-phenyl-C61-butyric acid isomethyl ester, [6,6]-phenyl C71-butyric acid methyl ester, C60, C70, SnO z (1.5≤z≤2), zinc oxide.

[0093] In some embodiments, the material of the first light absorption layer 13 is perovskite, and the material of the second light absorption layer 15 is perovskite.

[0094] Optionally, in some embodiments, the first direction is the incident direction of sunlight, for example, the L direction (the direction indicated by the arrow) in Figure 1-2, and the band gap of the material of the first light absorption layer 13 is greater than the band gap of the material of the second light absorption layer 15.

[0095] The band gap refers to the energy difference between the lowest point of the conduction band and the highest point of the valence band in a semiconductor material.

[0096] Optionally, the band gap of the material of the first light absorption layer 13 is 1.6eV-2.34eV, and the band gap of the material of the second light absorption layer 15 is 1.0eV-1.4eV. For example, the perovskite material of the first light absorption layer 13 is a bromine-iodine mixed perovskite, and the perovskite material of the second light absorption layer 15 is a tin-lead mixed perovskite.

[0097] Optionally, in some embodiments, the material of the second light absorption layer 15 is silicon, copper indium gallium selenide, copper indium selenide, cadmium telluride or gallium arsenide.

[0098] When the first direction is the incident direction of sunlight, sunlight first irradiates the first light absorption layer 13 . Setting the band gap of the material of the first light absorption layer 13 larger than the band gap of the material of the second light absorption layer 15 is beneficial to improving the efficiency of the solar cell.

[0099] In some embodiments, the chemical formula of the perovskite in the first light absorption layer 13 and the second light absorption layer 15 is ABX3, wherein A includes CH3(NH2)2 + 、CH(NH2)2 + 、CH3NH2 + 、Li + 、Na + , K + , Rb + 、Cs + At least one of, B includes Pb + 、Be 2+ Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ 、Zn 2+ 、Ge 2+ 、Fe 2+ 、Co 2+ 、Ni 2+ At least one of, X includes Cl - Br - , I - 、SCN - 、CNO - 、OCN - 、OSCN - SH - OH - 、CP - 、CN - 、SeCN - 、N3 - 、NO2 - In this way, it is convenient to flexibly select the specific type of perovskite according to actual needs.

[0100] In some embodiments, the second electrode layer 17 includes a metal. Optionally, the metal includes at least one of gold, silver, copper, aluminum, nickel, chromium, bismuth, platinum, magnesium, molybdenum, tungsten, and alloys thereof.

[0101] [Method for producing solar cells]

[0102] The solar cell provided in the embodiment of the present application is introduced above. The preparation method of the solar cell provided in the embodiment of the present application is introduced below, in which the parts similar to the above solar cell are not repeated here.

[0103] Figure 3 illustrates a method for fabricating a solar cell according to an embodiment of the present application. As shown in Figure 3 , fabrication method 300 includes providing a first electrode layer, a hole transport layer, a first light absorption layer, an interconnect layer, a second light absorption layer, an electron transport layer, and a second electrode layer, arranged sequentially along a first direction.

[0104] Among them, the interconnection layer includes SnO x layer, SnO x The layer includes at least three SnO x material, and along the first direction, x decreases gradually from 2 to 1.

[0105] In some embodiments, the preparation method 300 includes: providing a first electrode layer; preparing a hole transport layer on the first electrode layer; preparing a first light absorption layer on the hole transport layer; preparing an interconnection layer on the first light absorption layer; preparing a second light absorption layer on the interconnection layer; preparing an electron transport layer on the second light absorption layer; and preparing a second electrode layer on the electron transport layer.

[0106] In some embodiments, the preparation method 300 includes: preparing SnO on the first light absorbing layer x layer, forming an interconnection layer.

[0107] In some embodiments, the preparation method 300 includes: preparing a SnO2 layer on the first light absorbing layer, and preparing a SnO2 layer on the SnO2 layer. y layer (1<y<2), in SnO y A SnO layer was prepared on the layer to obtain SnO x layer.

[0108] In some embodiments, the preparation method 300 includes: depositing SnO on the first light absorbing layer using an atomic layer deposition device. x (1≤x≤2) material, to obtain SnO x layer.

[0109] Among them, when depositing SnO x During the material process, adjust the SnO x The ratio of tin to oxygen in the material decreases gradually from 2 to 1 along the first direction.

[0110] For example, first deposit SnO2, then adjust SnO x The material is SnO 1.76 , continue deposition, and then adjust SnO x The material is SnO 1.5 , continue deposition, and finally adjust SnO x The material is SnO, which is deposited to form SnO x layer.

[0111] In some embodiments, SnO xThe thickness d1 of the layer satisfies: 1 nm≤d1≤200 nm, optionally, 5 nm≤d1≤20 nm.

[0112] Specifically, SnO x The thickness d1 of the layer may be 1 nm, 10 nm, 20 nm, 50 nm, 80 nm, 100 nm, 150 nm, 180 nm, 200 nm, or a value between any two of the above values.

[0113] SnO x Setting the thickness of the layer within the above range is beneficial to improving the efficiency and stability of the solar cell.

[0114] In some embodiments, the thickness d2 of the SnO2 layer satisfies: 1 nm ≤ d2 ≤ 50 nm. Optionally, d2 satisfies: 5 nm ≤ d2 ≤ 10 nm.

[0115] Specifically, the thickness d2 of the SnO2 layer can be 1 nm, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, or a value between any two of the above values.

[0116] The thickness d2 of the SnO2 layer is set within the above range, which is beneficial to improving the performance of the battery.

[0117] In some embodiments, SnO y The thickness d3 of the layer satisfies: 1 nm ≤ d3 ≤ 50 nm. Optionally, d3 satisfies: 2 nm ≤ d3 ≤ 8 nm.

[0118] Specifically, SnO y The thickness d3 of the layer may be 1 nm, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, or a value between any two of the above values.

[0119] In some embodiments, the thickness d4 of the SnO layer satisfies: 1 nm≤d4≤50 nm. Optionally, d4 satisfies: 5 nm≤d4≤20 nm.

[0120] Specifically, the thickness d4 of the SnO layer may be 1 nm, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, or a value between any two of the above values.

[0121] The SnO2 layer, SnO y The SnO layer and the SnO layer are respectively set within the above ranges, which is beneficial to improving the efficiency and stability of the solar cell.

[0122] The present application also provides a photovoltaic module. Typically, the photovoltaic module includes the aforementioned solar cells, a welding ribbon connecting multiple solar cells, a junction box for current transmission, and a battery packaging component.

[0123] In some embodiments, the battery packaging component includes photovoltaic glass, which covers the solar cells to protect them. Photovoltaic glass has excellent light transmittance and high hardness, making it adaptable to large temperature swings between day and night and adverse weather conditions.

[0124] In some embodiments, the battery packaging component includes an EVA film, which is disposed between the photovoltaic glass and the solar cell and is used to bond the photovoltaic glass and the solar cell.

[0125] In some embodiments, the battery packaging component includes a photovoltaic backsheet, which also serves to protect the solar cells.

[0126] Optionally, the material of the photovoltaic backsheet can be a polyvinyl fluoride composite film or a thermoplastic elastic material. The material of the photovoltaic backsheet has the properties of insulation, waterproofness, and aging resistance.

[0127] In some embodiments, the battery packaging component includes a solar aluminum frame, which is made of aluminum alloy and has the characteristics of high strength and good corrosion resistance, and can support and protect the solar cell.

[0128] An embodiment of the present application further provides a photovoltaic device, comprising the photovoltaic assembly provided in the above embodiment.

[0129] In some embodiments, the photovoltaic device may also be a lighting device, an energy storage device, etc., and the embodiments of the present application include but are not limited to the above. For example, the photovoltaic device may be a solar water heater, a solar street light, a solar photovoltaic generator, etc.

[0130] [Example]

[0131] Below, the embodiment of the present application is described. The embodiment described below is exemplary and is only used to explain the present application, and is not to be construed as limiting the present application. Where specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents or instruments used that do not specify the manufacturer are conventional products that can be obtained commercially.

[0132] 1. Preparation of solar cells

[0133] [Example 1]

[0134] Example 1 corresponds to the structure of the solar cell shown in FIG. 1 .

[0135] First electrode layer: The first electrode layer is provided on a glass substrate. The material of the first electrode layer is indium tin oxide (ITO). The glass substrate having the first electrode layer is cleaned in sequence with acetone, alcohol, and deionized water, and dried for later use.

[0136] Hole transport layer: 0.3 mg of MeO-4PACz was added to 1 mL of ethanol and stirred. The ethanol solution of MeO-4PACz was spin-coated onto the first electrode layer 11 (spin coating speed 4000 rpm, spin coating time 30 s), and then transferred to a hot stage and annealed at 100°C for 10 min to form a hole transport layer.

[0137] First light-absorbing layer: 123 mg of CH(NH2)2I, 59 mg of CH(NH2)2Br, 46 mg of CsI, 25 mg of CsBr, 428 mg of PbI2, and 209 mg of PbBr2 were added to 1 mL of a mixture of DMF and DMSO (DMF:DMSO volume ratio of 3:1). The mixture was stirred at 600 rpm on a magnetic stirrer for 2 hours and filtered to prepare a perovskite precursor solution. 100 μL of this perovskite precursor solution was spin-coated onto the hole transport layer (spin-coating at 2000 rpm for 10 seconds, then at 4000 rpm for 30 seconds). 250 μL of chlorobenzene was then added dropwise to the spin-coated perovskite precursor solution. The perovskite precursor solution was then spin-coated again. The mixture was then transferred to a hot plate and annealed at 100°C for 10 minutes to form the first light-absorbing layer.

[0138] Interconnect layer: SnO is deposited on the first light absorbing layer using atomic layer deposition (ALD) equipment. x material, and a 15nm layer of SnO x , forming an interconnection layer. x During the material process, adjust the SnO x The ratio of tin to oxygen in the material, where x decreases gradually from 2 to 1 in the direction away from the first light-absorbing layer.

[0139] Second light-absorbing layer: 216 mg of CH(NH2)2I, 85 mg of CH3NH2I, 414 mg of PbI2, 335 mg of SnI2, and 0.3 mg of MeO-4PACz were added to 1 mL of a mixed solvent of DMF and DMSO (the volume ratio of DMF and DMSO was 3:1), stirred at 600 rpm on a magnetic stirrer for 2 hours, and filtered to prepare a perovskite precursor solution; 100 μL of the above perovskite precursor solution was spin-coated on the above interconnect layer (spin-coated at a spin-coating speed of 1000 rpm for 10 seconds, and then spin-coated at a spin-coating speed of 4000 rpm for 30 seconds), and then 300 μL of ethyl acetate was added dropwise to the spin-coated perovskite precursor solution, followed by spin-coating the above perovskite precursor solution, and then transferred to a hot stage for annealing at 100°C for 10 minutes to form a second light-absorbing layer.

[0140] Electron transport layer: A 10 nm thick layer of bathocuproin (BCP) was evaporated on the second light absorbing layer to form an electron transport layer.

[0141] Second electrode layer: A 100 nm thick layer of copper (Cu) was evaporated on the electron transport layer to form a second electrode layer, thereby finally obtaining the solar cell of Example 1.

[0142] [Examples 2-6]

[0143] The preparation of Example 2-6 is similar to that of Example 1, except that in Example 2-6, SnO x The thicknesses of the layers are 1 nm, 5 nm, 20 nm, 200 nm, and 250 nm respectively.

[0144] [Example 7]

[0145] The preparation of Example 7 is similar to that of Example 1, except that the preparation method of the interconnection layer is different. In Example 7, an 8nm SnO2 layer is prepared on the first light absorbing layer using an ALD device, and then a 5nm SnO2 layer is prepared on the SnO2 layer. 1.77 layer, and finally SnO 1.77 A 15 nm SnO layer is prepared on the layer to form an interconnection layer.

[0146] [Examples 8-13]

[0147] The preparation of Examples 8-13 is similar to that of Example 7, except that in Examples 8-13, the thickness of the SnO2 layer is 1 nm, 5 nm, 10 nm, 50 nm, 0.1 nm, and 60 nm, respectively.

[0148] [Examples 14-19]

[0149] The preparation of Examples 14-19 is similar to that of Example 7, except that in Examples 14-19, SnO1.77 The thicknesses of the layers are 1 nm, 2 nm, 8 nm, 50 nm, 0.1 nm, and 60 nm respectively.

[0150] [Examples 20-25]

[0151] The preparation of Examples 20-25 is similar to that of Example 7, except that in Examples 20-25, the thickness of the SnO layer is 1 nm, 5 nm, 20 nm, 50 nm, 0.1 nm, and 60 nm, respectively.

[0152] [Example 26]

[0153] The preparation of the first electrode layer, hole transport layer, first light absorbing layer, interconnect layer, second light absorbing layer, electron transport layer and second electrode layer in Example 26 is similar to that in Example 1, except that in Example 26, the first light absorbing layer and SnO x A first hole blocking layer is provided between the layers, and a second hole blocking layer is provided between the second light absorbing layer and the electron transport layer. Specifically, a 25 nm layer of C60 is evaporated on the first light absorbing layer to form the first hole blocking layer; then SnO is prepared on the first hole blocking layer. x layer (SnO x The preparation process of the layer is as shown in Example 1). A 25 nm thick layer of C60 is evaporated on the second light absorbing layer to form a second hole blocking layer; then an electron transport layer is prepared on the second hole blocking layer (the preparation process of the electron transport layer is as shown in Example 1).

[0154] [Example 27]

[0155] The preparation of Example 27 is similar to that of Example 1, except that in Example 27, the material of the second light-absorbing layer is single-crystalline silicon. Preparation of the second light-absorbing layer: Use a strong alkali to clean and texture the single-crystalline silicon to obtain a double-sided textured surface; Then, use a plasma-enhanced chemical vapor deposition (PECVD) device to prepare a 5nm layer of intrinsic i-type amorphous silicon and a 100nm layer of doped p-type amorphous silicon on one side of the double-sided textured single-crystalline silicon wafer, and then use the PECVD device to prepare a 5nm layer of intrinsic i-type amorphous silicon and a 100nm layer of doped N-type amorphous silicon on the other side; Use a physical vapor deposition (PVD) device to prepare a 100nm layer of ITO on both sides of the sample of the prepared amorphous silicon to obtain the second light-absorbing layer.

[0156] [Comparative Examples 1-2]

[0157] Comparative Example 1-2 is similar to Example 1 in preparation, except that the interconnection layer in Comparative Example 1 only includes SnO2 layer, and the interconnection layer in Comparative Example 2 only includes SnO2 layer. 1.77 layer.

[0158] Next, the test process of solar cell performance is described.

[0159] 2. Performance test of solar cells

[0160] Under standard simulated sunlight (AM 1.5G, 100mW / cm 2 ) irradiation, the battery performance is tested and the IV curve is obtained. According to the IV curve and the data fed back by the test equipment, the short-circuit current Jsc (unit: mA / cm 2 ), open-circuit voltage Voc (V), maximum optical output current Jmpp (mA), and maximum optical output voltage Vmpp (V). The cell's fill factor (FF) (in %) is calculated using the formula FF = Jsc × Voc / (Jmpp × Vmpp). The cell's photoelectric conversion efficiency (PCE) (in %) is calculated using the formula PCE = Jsc × Voc × FF / Pin. Pin represents the incident light input power (in mW).

[0161] The battery performance tests of Examples 1-27 and Comparative Examples 1-2 were carried out according to the above method. The test results are shown in Table 1 and Table 2. In Table 1, d1 represents SnO x In Table 2, d2 represents the thickness of the SnO2 layer, d3 represents the thickness of the SnO 1.77 The thickness of the layer, d4 represents the thickness of the SnO layer.

[0162] Table 1: Product parameters and performance test results of Examples 1-6, 26-27 and Comparative Examples 1-2

[0163] Table 2: Product parameters and performance test results of Examples 7-25 and Comparative Examples 1-2

[0164] From the comparison of the results of Example 1-25 and Comparative Example 1-2, it can be seen that the interconnection layer between the first light absorbing layer and the second light absorbing layer includes multiple types of tin oxides, and along the direction of the first light absorbing layer and the second light absorbing layer, the SnO in the interconnection layer is x By reducing the number of layers x from 2 to 1, the efficiency of the solar cell is significantly improved.

[0165] From the comparison of the results of Examples 1-6, it can be seen that SnO x When the thickness of the layer is set within an appropriate range, the efficiency of the solar cell is improved more significantly. Under the same conditions, the SnO x When the thickness of the layer is set within the range of 1 nm to 200 nm, the efficiency improvement effect of the solar cell is more obvious.

[0166] From the comparison of the results of Examples 7-13, it can be seen that when the thickness of the SnO2 layer is set within an appropriate range, the efficiency improvement effect of the solar cell is more obvious. Under the same other conditions, when the thickness of the SnO2 layer is set within the range of 1nm to 50nm, the efficiency improvement effect of the solar cell is more obvious.

[0167] From the comparison of the results of Examples 7, 14-19, it can be seen that SnO 1.77 When the thickness of the layer is set within an appropriate range, the efficiency of the solar cell is improved more significantly. Under the same conditions, the SnO 1.77 When the thickness of the layer is set within the range of 1 nm to 50 nm, the efficiency improvement effect of the solar cell is more obvious.

[0168] From the comparison of the results of Examples 7 and 20-25, it can be seen that when the thickness of the SnO layer is set within an appropriate range, the efficiency improvement effect of the solar cell is more obvious. Under the same conditions, when the thickness of the SnO layer is set within the range of 1nm to 50nm, the efficiency improvement effect of the solar cell is more obvious.

[0169] From the comparison of the results of Example 1 and Example 26, it can be seen that providing a hole blocking layer between the light absorbing layer and the electron transport layer is beneficial to improving the efficiency of the solar cell.

[0170] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and within the scope of the technical solution of the present application, embodiments having substantially the same structure as the technical concept and exerting the same effects are all included in the technical scope of the present application. In addition, within the scope of the subject matter of the present application, various modifications that can be conceived by those skilled in the art to the embodiments, and other methods constructed by combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A solar cell, characterized in that: include: A first electrode layer, a hole transport layer, a first light absorption layer, an interconnect layer, a second light absorption layer, an electron transport layer and a second electrode layer are sequentially arranged along a first direction; Wherein, the interconnection layer comprises SnO x layer, the SnO x The layer includes at least three kinds of SnO x material, and along the first direction, x decreases gradually from 2 to 1.

2. The solar cell according to claim 1, characterized in that The SnO x The thickness d1 of the layer satisfies: 1 nm ≤ d1 ≤ 200 nm.

3. The solar cell according to claim 2, characterized in that: The SnO x The thickness d1 of the layer satisfies: 5nm≤d1≤20nm.

4. The solar cell according to any one of claims 1 to 3, characterized in that The SnO x The layers include SnO2 layer, SnO y layer and SnO layer, the SnO y The SnO2 layer is located between the SnO layer and the SnO layer, and the SnO layer is located between the SnO2 layer and the SnO layer. y Between the layer and the second light absorbing layer, y satisfies: 1<y<2.

5. The solar cell according to claim 4, characterized in that: The thickness d2 of the SnO2 layer satisfies: 1nm≤d2≤50nm.

6. The solar cell according to claim 5, characterized in that: The thickness d2 of the SnO2 layer satisfies: 5nm≤d2≤10nm.

7. The solar cell according to any one of claims 4 to 6, characterized in that: The SnO y The thickness d3 of the layer satisfies: 1nm≤d3≤50nm.

8. The solar cell according to claim 7, characterized in that: The SnO y The thickness d3 of the layer satisfies: 2nm≤d3≤8nm.

9. The solar cell according to any one of claims 4 to 8, characterized in that The thickness d4 of the SnO layer satisfies: 1nm≤d4≤50nm.

10. The solar cell according to claim 9, characterized in that: The thickness d4 of the SnO layer satisfies: 5nm≤d4≤20nm.

11. The solar cell according to any one of claims 1 to 10, characterized in that The interconnection layer further includes a first hole blocking layer, which is located between the first light absorbing layer and the SnO x Between layers.

12. The solar cell according to any one of claims 1 to 11, characterized in that The solar cell further includes a second hole blocking layer, and the second hole blocking layer is located between the second light absorbing layer and the electron transporting layer.

13. The solar cell according to any one of claims 1 to 12, characterized in that The material of the first electrode layer includes: a transparent conductive oxide, and the transparent conductive oxide includes at least one of indium tin oxide, gallium zinc oxide, lanthanide metal-doped indium oxide, fluorine-doped tin oxide, indium-doped tungsten oxide, indium-doped zinc oxide, boron-doped zinc oxide, and aluminum-doped zinc oxide.

14. The solar cell according to any one of claims 1 to 13, characterized in that The material of the hole transport layer includes a P-type semiconductor, and the material of the electron transport layer includes an N-type semiconductor.

15. The solar cell according to claim 14, characterized in that: The material of the hole transport layer includes at least one of the following materials and their derivatives: [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphoric acid, [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphoric acid, [4-(3,6-dibromo-9H-carbazole-9-yl)butyl]phosphoric acid, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], poly-3-hexylthiophene, triphenylamine with triptycene as the core, 3,4-ethylenedioxythiophene-methoxytriphenylamine, N-(4-phenylamino)carbazole-spirobifluorene, poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid, polythiophene, nickel oxide, molybdenum oxide, cuprous iodide, cuprous oxide; The material of the electron transport layer includes at least one of the following materials and their derivatives: bathocuproin, [6,6]-phenyl-C61-butyric acid isomethyl ester, [6,6]-phenyl C71-butyric acid methyl ester, C60, C70, SnO z (1.5≤z≤2), zinc oxide.

16. The solar cell according to any one of claims 1 to 15, characterized in that The material of the first light absorption layer is perovskite, and the material of the second light absorption layer is perovskite.

17. The solar cell according to claim 16, characterized in that: The first direction is the incident direction of sunlight, and the band gap of the material of the first light absorption layer is greater than the band gap of the material of the second light absorption layer.

18. The solar cell according to claim 17, characterized in that: The chemical formula of the perovskite in the first light absorbing layer and the second light absorbing layer is ABX3, wherein: A includes CH3(NH2)2 + 、CH(NH2)2 + 、CH3NH2 + , Li + 、Na + , K + , Rb + , Cs + At least one of, B includes Pb + 、Be 2+ Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ 、Zn 2+ ,Ge 2+ , Fe 2+ 、Co 2+ 、Ni 2+ At least one of, X includes Cl - Br - ,I - 、SCN - 、CNO - 、OCN - 、OSCN - SH - OH - , CP - , CN - 、SeCN - 、N3 - 、NO2 - At least one of .

19. The solar cell according to any one of claims 1 to 18, characterized in that The second electrode layer includes a metal, and the metal includes at least one of gold, silver, copper, aluminum, nickel, chromium, bismuth, platinum, magnesium, molybdenum, tungsten and alloys thereof.

20. The solar cell according to claim 11, characterized in that The first hole blocking layer includes fullerene and its derivatives, SnO z At least one of (1.5≤z≤2).

21. The solar cell according to claim 12, characterized in that: The second hole blocking layer includes fullerene and its derivatives, SnO z At least one of (1.5≤z≤2).

22. A method for preparing a solar cell, characterized in that: include: Providing a first electrode layer, a hole transport layer, a first light absorption layer, an interconnect layer, a second light absorption layer, an electron transport layer, and a second electrode layer arranged in sequence along a first direction; Wherein, the interconnection layer comprises SnO x layer, the SnO x The layer includes at least three kinds of SnO x Materials, and along the In the first direction, the gradient of x decreases from 2 to 1.

23. The preparation method according to claim 22, characterized in that: The method of providing a first electrode layer, a hole transport layer, a first light absorption layer, an interconnect layer, a second light absorption layer, an electron transport layer and a second electrode layer arranged in sequence along a first direction comprises: providing the first electrode layer; preparing the hole transport layer on the first electrode layer; preparing the first light absorbing layer on the hole transport layer; preparing the interconnection layer on the first light absorbing layer; preparing the second light absorbing layer on the interconnection layer; preparing the electron transport layer on the second light absorbing layer; The second electrode layer is formed on the electron transport layer.

24. The preparation method according to claim 23, characterized in that: The step of preparing the interconnection layer on the first light absorbing layer comprises: The SnO is prepared on the first light absorbing layer. x layer, forming the interconnection layer.

25. The preparation method according to claim 24, characterized in that: The SnO x Layers, including: A SnO2 layer is formed on the first light absorbing layer, and a SnO y layer (1<y<2), in the SnO y A SnO layer is prepared on the layer to obtain the SnO x layer.

26. The preparation method according to claim 24, characterized in that: The SnO x Layers, including: SnO is deposited on the first light absorbing layer using an atomic layer deposition device. x (1≤x≤2) material, to obtain the SnO x layer; Wherein, during the deposition of the SnO x materials process, adjust the SnO x The ratio of tin element to oxygen element in the material decreases gradually from 2 to 1 along the first direction.

27. The preparation method according to any one of claims 22 to 26, characterized in that: The SnO x The thickness d1 of the layer satisfies: 1 nm ≤ d1 ≤ 200 nm.

28. The preparation method according to claim 27, characterized in that: The SnO x The thickness d1 of the layer satisfies: 5nm≤d1≤20nm.

29. The preparation method according to claim 25, characterized in that: The thickness d2 of the SnO2 layer satisfies: 1nm≤d2≤50nm.

30. The preparation method according to claim 29, characterized in that: The thickness d2 of the SnO2 layer satisfies: 5nm≤d2≤10nm.

31. The preparation method according to claim 25, characterized in that: The SnO y The thickness d3 of the layer satisfies: 1nm≤d3≤50nm.

32. The preparation method according to claim 31, characterized in that: The SnO y The thickness d3 of the layer satisfies: 2nm≤d3≤8nm.

33. The preparation method according to claim 25, characterized in that: The thickness d4 of the SnO layer satisfies: 1nm≤d4≤50nm.

34. The preparation method according to claim 33, characterized in that: The thickness d4 of the SnO layer satisfies: 5nm≤d4≤20nm.

35. A photovoltaic module, characterized in that: The invention comprises a solar cell according to any one of claims 1 to 21, and / or a solar cell prepared by the preparation method according to any one of claims 22 to 34.

36. A photovoltaic device, characterized in that: Comprising the photovoltaic module according to claim 35.

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