Electronic transport layer, preparation method thereof and perovskite solar cell

Abstract

The application relates to the technical field of solar cells, in particular to an electron transport layer, a preparation method thereof and a perovskite solar cell. The preparation method of the electron transport layer comprises the following steps: S1, preparing a first metal oxide layer on the surface of a perovskite absorption layer; wherein the thickness of the first metal oxide layer is 1 nm-3 nm; S2, vacuum evaporation deposition of a discontinuous fullerene layer on the surface of the first metal oxide layer; wherein the evaporation deposition rate is 1 A / S-5 A / S; S3, preparing a second metal oxide layer on the surface of the fullerene layer to obtain the electron transport layer; wherein the thickness of the second metal oxide layer is greater than that of the fullerene layer, and the second metal oxide layer at least partially contacts the first metal oxide layer. The electron transport layer structure prepared by the application is wrapped with a metal oxide layer and a fullerene layer, the stability of the fullerene layer is improved, the bonding force between layers is improved, and the battery efficiency is improved.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to an electron transport layer and a preparation method thereof, and a perovskite solar cell. Background Art

[0002] Currently, perovskite solar cells typically utilize a process that involves first depositing a fullerene layer on the perovskite absorber layer via vapor deposition, followed by a metal oxide layer on top of the fullerene layer, to create a double-layer electron transport layer. However, the electron transport layer produced using this process exhibits poor bonding between the upper and lower interfaces of the fullerene layer (perovskite absorber layer / fullerene layer, fullerene layer / metal oxide layer), resulting in easy detachment. Furthermore, the metal oxide layer exhibits poor adhesion and growth, which reduces cell efficiency. Summary of the Invention

[0003] Based on this, the present application provides an electron transport layer and a preparation method thereof, and a perovskite solar cell to solve the above technical problems.

[0004] The first aspect of the present application provides a method for preparing an electron transport layer, comprising the following steps: S1, preparing a first metal oxide layer on the surface of a perovskite absorption layer; wherein the thickness of the first metal oxide layer is 1 nm to 3 nm; S2, depositing a discontinuous fullerene layer on the surface of the first metal oxide layer by vacuum evaporation; wherein the vacuum evaporation deposition rate is 1 Å / S to 5 Å / S; S3, preparing a second metal oxide layer on the surface of the fullerene layer to obtain an electron transport layer; wherein the thickness of the second metal oxide layer is greater than the thickness of the fullerene layer, and the second metal oxide layer is at least partially in contact with the first metal oxide layer.

[0005] In some embodiments, the fullerene layer has a thickness of 5 nm to 25 nm.

[0006] In some embodiments, the second metal oxide layer has a thickness of 12 nm to 35 nm.

[0007] In some embodiments, the fullerene layer includes at least one of fullerene and its derivatives.

[0008] In some embodiments, the first metal oxide layer comprises SnO x , Al2O3, WO3, Nb2O5, indium tin oxide (ITO), indium zinc oxide (IZO). Among them, SnO x In the equation, 1≤x≤2.

[0009] In some embodiments, the second metal oxide layer comprises SnO x, Al2O3, WO3, Nb2O5, indium tin oxide (ITO), indium zinc oxide (IZO). Among them, SnO x In the equation, 1≤x≤2.

[0010] In some embodiments, step S1 includes: depositing a first metal oxide layer on the surface of the perovskite absorption layer by vacuum evaporation.

[0011] In some embodiments, step S3 includes: depositing a second metal oxide layer on the surface of the fullerene layer using an atomic layer deposition device.

[0012] The second aspect of the present application provides an electron transport layer, which is prepared by the preparation method of the electron transport layer provided in the first aspect of the present application.

[0013] A third aspect of the present application provides a perovskite solar cell, which includes the electron transport layer provided in the second aspect of the present application.

[0014] This application prepares a thin metal oxide layer before depositing the fullerene layer, then prepares a discontinuous fullerene layer by controlling the vacuum evaporation deposition rate to 1Å / S~5Å / S, and finally prepares a metal oxide layer on the surface of the fullerene layer to prepare an electron transport layer. The thin metal oxide layer prepared in the first step provides nucleation sites for the preparation of the metal oxide layer in the third step, thereby improving the growth and bonding of the metal oxide layer in the third step; at the same time, the second step adopts a higher deposition rate, causing the material in the fullerene layer to curl up and agglomerate to form a discontinuous fullerene layer; and the third step makes the metal oxide layers on the upper and lower sides of the fullerene layer at least partially contact, thereby obtaining an electron transport layer structure in which the metal oxide layer wraps the fullerene layer, improving the stability of the fullerene layer and the bonding strength between the layers, thereby improving the battery efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. 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 these drawings without paying any creative work.

[0016] Figure 1 This is a process flow chart of a method for preparing an electron transport layer in some embodiments of the present application.

[0017] Figure 2 Schematic diagram of the structure of the electron transport layer in some embodiments of the present application.

[0018] Reference Signs List

[0019] 1. first metal oxide layer; 2. fullerene layer; 3. second metal oxide layer. DETAILED DESCRIPTION

[0020] Reference will now be made in detail to the embodiments of the present application, one or more examples of which are set forth below. Each example is provided as an explanation and not as a limitation of the present application. Indeed, it will be apparent to one of ordinary skill in the art that numerous modifications and variations of the present application are possible in light of the above teachings. For example, features described or illustrated as part of one embodiment can be used with another embodiment to yield still a further embodiment.

[0021] Thus, it is intended that the present application cover modifications and variations of this application provided they come within the scope of the appended claims and their equivalents. Other objects, features, and aspects of the present application are disclosed in or are apparent from the following detailed description of the application. It is to be understood by the foregoing description that the form of the application herein disclosed is to be considered only as an example and not a limitation of the application. It is the following claims, including all equivalents thereof, which are intended to define the scope of the application.

[0022] In the present application, the technical features described in an open way include both the closed technical solution consisting of the listed features and the open technical solution containing the listed features.

[0023] In the present application, when referring to a numerical interval, unless otherwise specified, the numerical interval is considered to be continuous and includes the minimum value and the maximum value of the range, as well as every value between the minimum value and the maximum value. Further, when the range refers to integers, every integer between the minimum value and the maximum value of the range is included. In addition, when multiple ranges are provided to describe a feature or a characteristic, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein are to be understood as including any and all sub-ranges subsumed therein.

[0024] In the present application, when referring to a data range, if only the unit is indicated after the right endpoint, it means that the units of the left endpoint and the right endpoint are the same. For example, 100~150nm means that the units of the left endpoint "100" and the right endpoint "150" are both nm (nanometer).

[0025] If not specifically stated, all embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions.

[0026] If not specifically stated, all technical features and optional technical features of the present application can be combined with each other to form new technical solutions.

[0027] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly, preferably sequentially. For example, a statement that a method includes steps (a) and (b) indicates that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, a statement that a method may also include step (c) indicates 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.

[0028] Unless otherwise specified, the terms "include" and "comprising" used in this application may be open-ended or closed-ended. For example, "include" and "comprising" may indicate that other components not listed may also be included or that only the listed components are included.

[0029] like Figure 1 As shown, the first aspect of the present application provides a method for preparing an electron transport layer, comprising the following steps: S1, preparing a first metal oxide layer 1 on the surface of the perovskite absorption layer. The thickness of the first metal oxide layer 1 is 1 nm to 3 nm.

[0030] S2. Vacuum evaporation is used to deposit a discontinuous fullerene layer 2 on the surface of the first metal oxide layer 1. The vacuum evaporation deposition rate is 1 Å / s to 5 Å / s.

[0031] S3. Forming a second metal oxide layer 3 on the surface of the fullerene layer 2 to form an electron transport layer. The second metal oxide layer 3 is thicker than the fullerene layer 2 and is in at least partial contact with the first metal oxide layer 1.

[0032] It is understandable that the thickness of the first metal oxide layer 1 is 1 nm to 3 nm, including but not limited to 1 nm, 1.5 nm, 2 nm, 2.5 nm, and 3 nm.

[0033] If the first metal oxide layer is too thick, the overall thickness of the electron transport layer increases, thereby reducing battery efficiency. This also reduces the bonding strength between the first metal oxide layer 1 and the fullerene layer 2, impacting the performance of the fullerene itself. Therefore, the application sets the thickness of the first metal oxide layer 1 to 1nm-3nm to reduce the overall thickness of the electron transport layer, improve the bonding strength between the first metal oxide layer 1 and the fullerene layer 2, and thus enhance battery efficiency.

[0034] The rate of vacuum evaporation deposition in step S2 is 1Å / S~5Å / S, including but not limited to 1Å / S, 1.5Å / S, 2Å / S, 2.5Å / S, 3Å / S, 3.5Å / S, 4Å / S, 4.5Å / S, and 5Å / S.

[0035] In this application, a relatively thin (1nm~3nm) metal oxide layer is first prepared before depositing the fullerene layer 2, and then a discontinuous fullerene layer 2 is prepared by controlling the evaporation deposition rate to 1Å / S~5Å / S. Finally, a metal oxide layer is prepared on the surface of the fullerene layer 2 to obtain an electron transport layer.

[0036] Among them, the thin metal oxide layer prepared in the first step provides a nucleation site for the preparation of the metal oxide layer in the third step, thereby improving the growth and bonding of the metal oxide layer in the third step; at the same time, a higher deposition rate is used in the second step, so that the material in the fullerene layer 2 curls up and agglomerates to form a discontinuous fullerene layer 2; and then through the third step, the metal oxide layers on the upper and lower sides of the fullerene layer 2 are at least partially in contact, thereby obtaining an electron transport layer structure in which the metal oxide layer wraps the fullerene layer 2 (such as Figure 2 As shown in FIG, the stability of the fullerene layer 2 is improved, the bonding force between the layers is enhanced, and thus the battery efficiency is improved.

[0037] In some embodiments, the thickness of the fullerene layer 2 is 5 nm to 25 nm, including but not limited to 5 nm, 10 nm, 15 nm, 20 nm, and 25 nm.

[0038] It can be understood that the thickness of the fullerene layer 2 in the present application refers to the maximum distance between the fullerene layer 2 and the surface of the first metal oxide layer 1 (the surface close to the fullerene layer 2 ).

[0039] In some embodiments, the thickness of the second metal oxide layer 3 is 12 nm to 35 nm, including but not limited to 12 nm, 15 nm, 20 nm, 25 nm, 30 nm, and 35 nm.

[0040] It is understood that the thickness of the second metal oxide layer 3 in the present application refers to the maximum distance between the second metal oxide layer 3 and the surface of the first metal oxide layer 1 (the surface close to the fullerene layer 2 ).

[0041] In some embodiments, the fullerene layer 2 includes at least one of fullerene and its derivatives.

[0042] In some embodiments, fullerenes and their derivatives include but are not limited to C 20 、C 60 、C 70 、C 76One or more of: [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), and indene-C60 bisadduct (ICBA). The selection of these materials allows for a better match between the energy levels of the perovskite absorption layer and the electron transport layer, forming an efficient electron transport channel, preventing electron and hole recombination and improving photoelectric conversion efficiency.

[0043] In some embodiments, the first metal oxide layer 1 includes SnO x , Al2O3, WO3, Nb2O5, indium tin oxide (ITO), indium zinc oxide (IZO). Among them, SnO x In the equation, 1≤x≤2.

[0044] In some embodiments, the second metal oxide layer 3 includes SnO x , Al2O3, WO3, Nb2O5, indium tin oxide (ITO), indium zinc oxide (IZO). Among them, SnO x In the equation, 1≤x≤2.

[0045] In some embodiments, step S1 includes: depositing a first metal oxide layer 1 on the surface of the perovskite absorption layer by vacuum evaporation.

[0046] In some embodiments, step S1 includes: adding oxide material to a point source crucible, placing the perovskite solar cell to be processed (the perovskite absorption layer has been prepared) into an evaporation device, and evacuating the vacuum to 2×10 -4 Pa, and then wait for the process to begin. Turn on the power, stabilize the vacuum evaporation deposition rate at 0.5Å / s to 1Å / s, and begin evaporating the first metal oxide layer 1.

[0047] In some embodiments, step S2 includes: adding high-purity fullerene material to a point source crucible, placing the perovskite solar cell to be processed (the first metal oxide layer 1 has been prepared) into an evaporation device, and evacuating the vacuum to 2×10 - 4 Pa below, waiting to start the process. Preheat the fullerene material to the preset temperature, and increase the vacuum evaporation deposition rate to 1Å / s-5Å / s within the preset time. Simultaneously, open the main baffle of the evaporation equipment and rotate the substrate to begin deposition of a 5nm-25nm fullerene layer 2.

[0048] It is understood that the “high-purity fullerene material” in this application refers to a fullerene material with a purity of 99.5% or more.

[0049] The "preset temperature" for preheating in this application is generally about 60% of the initial vaporization temperature of the fullerene material.

[0050] For example: Assume that the evaporation equipment evaporates C60 The rate of output starts at 300℃, then C 60 The initial steaming temperature of the material is 180℃.

[0051] The "preset time" in this application is 3 minutes to 5 minutes, including but not limited to 3 minutes, 3.5 minutes, 4 minutes, 4.5 minutes, and 5 minutes.

[0052] In some embodiments, step S2 may further include the following steps: after the fullerene layer 2 is deposited, the main baffle is closed, the substrate is rotated, and the substrate is taken out after being cooled down, and directly transferred into the ALD (Atomic Layer Deposition) equipment chamber to prepare for the deposition of the second metal oxide layer 3.

[0053] In some embodiments, after step S2, the process further includes: preheating the source bottle and the substrate in the ALD device before the fullerene layer 2 is prepared.

[0054] In some embodiments, step S3 includes: depositing a second metal oxide layer 3 on the surface of the fullerene layer 2 using an atomic layer deposition device.

[0055] In some embodiments, step S3 includes: using an atomic layer deposition device to introduce an excess tin source and excess water in stages to form a second metal oxide layer 3 with a thickness of 12 nm to 35 nm.

[0056] It can be understood that the above-mentioned “stage-by-stage introduction” refers to the process of: introducing a tin source, purging with nitrogen, introducing water, purging with nitrogen, introducing a tin source again, and so on.

[0057] In some embodiments, the "tin source" is tetramethylaminotin.

[0058] The second aspect of the present application provides an electron transport layer, which is prepared by the preparation method of the electron transport layer provided in the first aspect of the present application.

[0059] Compared with the traditional double-layer electron transport layer, the electron transport layer provided in the present application with the upper and lower metal oxide layers covering the fullerene layer 2 structure improves the adhesion of the upper and lower film layers of the fullerene layer 2, has better multi-film layer structure integration, avoids the occurrence of fullerene material agglomeration problems to the greatest extent, and improves the performance of the metal oxide layer itself.

[0060] A third aspect of the present application provides a perovskite solar cell, which includes the electron transport layer provided in the second aspect of the present application.

[0061] The perovskite solar cell provided in this application has excellent photoluminescence effect, excellent cell stability and cell efficiency.

[0062] It can be understood that the perovskite solar cells in this application mainly refer to perovskite single-junction cells, perovskite crystalline silicon tandem cells or full perovskite tandem cells.

[0063] For example, a perovskite single-junction cell includes: a first electrode layer, a hole transport layer, a perovskite absorption layer, an electron transport layer, and a second electrode layer, and may also include a modification layer located between the electron transport layer and the metal electrode. The electron transport layer uses the cell transport layer provided in this application.

[0064] In some embodiments, the material of the first electrode layer includes a transparent conductive oxide, which 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.

[0065] In some embodiments, 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.

[0066] In some embodiments, 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, and cuprous oxide.

[0067] In some embodiments, the chemical formula of the perovskite in the perovskite absorber layer is ABX3, wherein A comprises CH3(NH2)2 + 、CH(NH2)2 + 、CH3NH2 + 、Li + 、Na + , K + , Rb + 、Cs + At least one of, B includes Pb 2+ 、Be 2+ Mg 2+ , Ca 2+ 、Sr 2 + 、Ba 2+ 、Zn 2+ 、Ge 2+ 、Fe2+ 、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 .

[0068] In some embodiments, the material of the second electrode layer includes one or more of silver, copper, gold, aluminum, palladium, titanium, chromium, and nickel.

[0069] Illustratively, a perovskite crystalline silicon tandem cell includes a silicon substrate (silicon cell), a composite layer, and a perovskite single junction cell, wherein the perovskite single junction cell includes the electron transport layer provided in the present application.

[0070] Exemplarily, the all-perovskite stack cell includes: a top cell and a bottom cell, wherein the top cell is a lead-based wide-bandgap perovskite, the bottom cell is a tin-based narrow-bandgap perovskite, and the top cell and / or the bottom cell include the electron transport layer provided in this application.

[0071] In some embodiments, the present application provides a method for preparing a perovskite solar cell, comprising the following steps: providing a first electrode layer, a hole transport layer, a perovskite absorption layer, an electron transport layer, and a second electrode layer arranged in sequence.

[0072] In some embodiments, the above preparation method includes: providing a first electrode layer; preparing a hole transport layer on the surface of the first electrode layer; preparing a perovskite absorption layer on the surface of the hole transport layer; preparing an electron transport layer on the surface of the perovskite absorption layer; and preparing a second electrode layer on the surface of the electron transport layer.

[0073] In some embodiments, the above preparation method includes preparing a first metal oxide layer 1 on the surface of the perovskite absorption layer.

[0074] In some embodiments, the preparation method includes forming a discontinuous fullerene layer 2 on the surface of the first metal oxide layer 1 .

[0075] In some embodiments, the preparation method includes forming a second metal oxide layer 3 on the surface of the fullerene layer 2, wherein the second metal oxide layer 3 is in at least partial contact with the first metal oxide layer 1, thereby forming an electron transport layer.

[0076] In some embodiments, the present application further provides a photovoltaic module. The photovoltaic module includes the above-mentioned perovskite solar cell, a welding ribbon, a junction box, and a battery packaging component. The welding ribbon is used to connect multiple perovskite solar cells, and the junction box is used for current transmission.

[0077] In some embodiments, the cell encapsulation component includes photovoltaic glass, which covers the perovskite solar cell to protect the solar cell. Photovoltaic glass has excellent light transmittance and high hardness, and can withstand large temperature swings between day and night and adverse weather conditions.

[0078] In some embodiments, the battery packaging component includes an EVA film, which is disposed between the photovoltaic glass and the solar cell to bond the photovoltaic glass and the perovskite solar cell.

[0079] The “EVA film” in this application refers to a material copolymerized with ethylene and vinyl acetate.

[0080] In some embodiments, the battery packaging component includes a photovoltaic backsheet, which also serves to protect the solar cells.

[0081] In some embodiments, the photovoltaic backsheet may be made of a polyvinyl fluoride composite film or a thermoplastic elastic material. The photovoltaic backsheet material has properties such as insulation, waterproofness, and aging resistance.

[0082] 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.

[0083] In some embodiments, the present application further provides a photovoltaic device, which includes the photovoltaic assembly provided by the above embodiment.

[0084] In some embodiments, the photovoltaic device may be a lighting device, an energy storage device, etc., and the embodiments provided herein include but are not limited to the above. For example, the photovoltaic device may also be a solar water heater, a solar street light, a solar photovoltaic generator, etc.

[0085] In order to make the purpose and advantages of this application clearer, the preparation method of the microcrystalline silicon film of this application and its effects are further described in detail below in conjunction with specific examples. It should be understood that the specific examples described here are only used to explain this application and shall not be used to limit this application. The following examples do not include other components except unavoidable impurities unless otherwise specified. The drugs and instruments used in the examples are all conventionally selected in the art unless otherwise specified. The experimental methods for which specific conditions are not specified in the examples shall be implemented according to conventional conditions, such as the conditions described in the literature, books, or methods recommended by the manufacturer.

[0086] The present application will be further described below with reference to specific embodiments.

[0087] Example 1

[0088] This embodiment provides a perovskite single-junction battery, and the specific preparation process is as follows: First electrode layer: A first electrode layer is set on a glass substrate. The material of the first electrode layer is indium tin oxide (ITO). The glass substrate with the first electrode layer is cleaned in sequence with acetone-alcohol-deionized water, and then dried for use.

[0089] Hole transport layer: A poly(2,3-dihydrothieno-1,4-dioxolane)-poly(styrene sulfonate) (PEDOT:PSS) aqueous solution was dropped onto the first electrode layer and spin-coated at 5000 rpm to form a film with a thickness of 30 nm. The film was then thermally annealed at 150°C for 20 min.

[0090] Perovskite absorber layer: The precursor solution (the molar ratio of PbI2 and methylamine iodide (MAI) is 1:1; the volume ratio of solvent: dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) is 4:1) is dropped onto the hole transport layer and spin-coated at 5000 rpm to form a film. During the spin-coating process, toluene antisolvent is quickly added, and the film is annealed at 150°C for 60 minutes.

[0091] Electron transport layer: S1, vacuum evaporate a layer of SnO2 on the surface of the above perovskite absorption layer. The vacuum degree is 2×10 -4 Below Pa, the vacuum evaporation deposition rate is 0.5Å / S and the thickness of the SnO2 layer is 3nm.

[0092] S2, vacuum evaporating a layer of fullerene C on the surface of the above SnO2 layer 60 Layer. Among them, the vacuum degree is 2×10 -4 Pa below, the evaporation deposition rate is 1Å / S, fullerene C 60 The thickness of the layer is 22 nm.

[0093] S3, using ALD equipment to deposit the fullerene C 60A SnO2 layer is deposited on the surface of the layer, wherein the thickness of the SnO2 layer is 25 nm, and the second metal oxide layer 3 is in at least partial contact with the first metal oxide layer 1.

[0094] Second electrode layer: a 200nm thick copper electrode layer was evaporated on the surface of the electron transport layer.

[0095] Example 2

[0096] The main difference between this embodiment and embodiment 1 is that the thickness of the first metal oxide layer 1 in step S1 is 1 nm.

[0097] Example 3

[0098] The main difference between this embodiment and embodiment 1 is that the evaporation deposition rate in step S2 is 5 Å / S.

[0099] Example 4

[0100] The main difference between this embodiment and embodiment 1 is that: fullerene C 60 The thickness of the layer is 5 nm.

[0101] Example 5

[0102] The main difference between this embodiment and embodiment 1 is that: fullerene C 60 The thickness of the layer was 25 nm.

[0103] Example 6

[0104] The main difference between this embodiment and embodiment 1 is that the thickness of the second metal oxide layer is 12 nm.

[0105] Example 7

[0106] The main difference between this embodiment and embodiment 1 is that the thickness of the second metal oxide layer is 35 nm.

[0107] Comparative Example 1

[0108] The main difference between this comparative example and Example 1 is that the electron transport layer is a traditional double-layer electron transport layer.

[0109] Electron transport layer: A layer of fullerene C is prepared by vacuum evaporation on the surface of the perovskite absorption layer. 60 Layer. Among them, the vacuum degree is 2×10 -4 Pa below, the evaporation deposition rate is 0.2Å / s, fullerene C 60 The thickness of the layer is 22 nm.

[0110] ALD equipment was used to deposit the fullerene C 60A SnO2 layer is deposited on the surface of the layer, wherein the thickness of the SnO2 layer is 25 nm.

[0111] Comparative Example 2

[0112] The difference between this comparative example and Example 1 is that the thickness of the first metal oxide layer 1 in step S1 is 4 nm.

[0113] Comparative Example 3

[0114] The difference between this comparative example and Example 1 is that the evaporation deposition rate in step S2 is 0.05 Å / S.

[0115] Test Case

[0116] The perovskite solar cells prepared in the above embodiments and comparative examples were subjected to cell efficiency tests. The measured electrical properties included the open circuit voltage (Voc), short circuit current (Isc), fill factor (FF), series resistance (Rs), leakage resistance (Rsh), and conversion efficiency (Eff) of the solar cells. The results are shown in Table 1 below.

[0117] Table 1

[0118] Voc(mV) Isc(A) FF(%) Rs(mΩ) Rsh(Ω) Eff(%) Example 1 1.26 20.96 82.14 32.292 133231.7 21.70 Example 2 1.25 20.74 79.72 34.130 116032.9 20.71 Example 3 1.20 19.71 77.55 40.825 27093.0 18.35 Example 4 1.19 19.22 76.84 40.863 18056.5 17.63 Example 5 1.19 18.59 76.89 40.110 13785.1 16.96 Example 6 1.18 19.34 75.99 49.676 20248.3 17.39 Example 7 1.19 19.54 74.75 51.205 20114.5 17.42 Comparative Example 1 1.17 18.63 74.38 65.906 15139.08 16.22 Comparative Example 2 1.15 17.89 71.67 70.128 10316.9 14.73 Comparative Example 3 1.27 20.71 82.10 39.543 157477.9 21.67

[0119] According to the comparison of the experimental data in Table 1, it can be seen that the electron transport layer preparation method provided by the present application is used to prepare an electron transport layer structure in which a metal oxide layer wraps a fullerene layer, which improves the stability of the fullerene layer and the bonding strength between the layers, thereby improving the battery efficiency.

[0120] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0121] The above embodiments merely illustrate several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A method for preparing an electron transport layer, characterized in that: The following steps are involved: S1. Preparing a first metal oxide layer on the surface of the perovskite absorption layer; wherein the thickness of the first metal oxide layer is 1 nm to 3 nm; S2. Vacuum evaporation deposits a discontinuous fullerene layer on the surface of the first metal oxide layer; wherein the vacuum evaporation deposition rate is 1 Å / s to 5 Å / s; S3. Preparing a second metal oxide layer on the surface of the fullerene layer to obtain the electron transport layer; wherein the thickness of the second metal oxide layer is greater than the thickness of the fullerene layer, and the second metal oxide layer is in at least partial contact with the first metal oxide layer.

2. The method for preparing an electron transport layer according to claim 1, wherein: The thickness of the fullerene layer is 5 nm to 25 nm.

3. The method for preparing an electron transport layer according to claim 1, wherein: The thickness of the second metal oxide layer is 12 nm to 35 nm.

4. The method for preparing an electron transport layer according to claim 1, wherein: The fullerene layer includes at least one of fullerene and its derivatives.

5. The method for preparing an electron transport layer according to claim 1, wherein: The first metal oxide layer includes SnO x , at least one of Al2O3, WO3, Nb2O5, indium tin oxide, and indium zinc oxide; Wherein, the SnO x In the equation, 1≤x≤2.

6. The method for preparing an electron transport layer according to any one of claims 1 to 5, characterized in that: The second metal oxide layer includes SnO x , at least one of Al2O3, WO3, Nb2O5, indium tin oxide, and indium zinc oxide; Wherein, the SnO x In the equation, 1≤x≤2.

7. The method for preparing an electron transport layer according to any one of claims 1 to 5, characterized in that: Step S1 includes: The first metal oxide layer is deposited on the surface of the perovskite absorption layer by vacuum evaporation.

8. The method for preparing an electron transport layer according to any one of claims 1 to 5, characterized in that: Step S3 includes: The second metal oxide layer is deposited on the surface of the fullerene layer using an atomic layer deposition device.

9. An electron transport layer, characterized in that The electron transport layer is prepared by the method for preparing an electron transport layer according to any one of claims 1 to 8.

10. A perovskite solar cell, characterized in that: The perovskite solar cell comprises the electron transport layer according to claim 9.

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