All-inorganic perovskite solar cell and its preparation method and application

Abstract

The present invention provides an all-inorganic perovskite solar cell and its preparation method and application. The all-inorganic perovskite solar cell comprises: a conductive substrate, an electron transport layer, an all-inorganic perovskite photoactive layer, a hole transport layer, and an anode electrode, which are stacked in sequence. The electron transport layer comprises a doped tin oxide electron transport layer and a zinc oxide electron transport layer; the doped tin oxide electron transport layer is obtained by doping with bis(pentafluorophenyl)zinc; and the zinc oxide electron transport layer is spin-coated on the doped tin oxide electron transport layer. The all-inorganic perovskite solar cell of the present invention has high energy conversion efficiency, a simple preparation process, mild and easily controllable conditions, and can be widely used in the photovoltaic field.

Description

Technical Field

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

[0002] Faced with depleting fossil energy resources, developing new, clean, and renewable energy sources is a key strategy for addressing the energy crisis. Solar energy, with its inexhaustible nature, has garnered widespread attention from researchers. With the rapid development of society, the demand for solar cells has increased significantly, leading to the development of solar cells that are more cost-effective, have simpler manufacturing processes, and exhibit superior efficiency and stability. Notably, perovskite solar cells, due to their solution-based preparation, readily available raw materials, and their demonstrated power conversion efficiency (PCE) of up to 25.7%, are considered the most commercially viable photovoltaic device and have become a research hotspot in the photovoltaic field.

[0003] Although organic-inorganic hybrid perovskite solar cells are currently highly efficient, the organic components (such as methylamine and formamidine) are easily volatilized at high temperatures, resulting in poor thermal stability of the perovskite, which is not conducive to long-term operation of the device. Replacing methylamine and formamidine with cesium to prepare all-inorganic cesium lead iodine bromine-based devices can significantly improve their thermal stability. In addition, the development of stacked solar cells with all-inorganic perovskite solar cells as top cells is also very promising. Therefore, all-inorganic perovskite solar cells have developed rapidly in recent years. However, due to the relatively wide band gap of all-inorganic perovskites, the energy level arrangement between the perovskite and the carrier transport layer is not ideal, resulting in more serious recombination than organic-inorganic hybrid perovskite devices, which seriously limits the energy conversion efficiency of all-inorganic perovskite solar cells. Summary of the Invention

[0004] In view of this, the main purpose of the present invention is to provide an all-inorganic perovskite solar cell and its preparation method and application, to achieve the upward shift of the Fermi level of tin oxide, to form a more matching energy level with zinc oxide, and to improve the energy conversion efficiency of the all-inorganic perovskite solar cell, in order to solve at least one of the above-mentioned technical problems.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] As a first aspect of the present invention, an all-inorganic perovskite solar cell is provided, comprising: a conductive substrate, an electron transport layer, an all-inorganic perovskite photoactive layer, a hole transport layer and an anode electrode stacked in sequence, wherein the electron transport layer is composed of a doped tin oxide electron transport layer and a zinc oxide electron transport layer; the doped tin oxide electron transport layer is obtained by doping with di(pentafluorophenyl)zinc (abbreviated as ZCF); and the zinc oxide electron transport layer is spin-coated on the doped tin oxide electron transport layer.

[0007] As a second aspect of the present invention, a method for preparing an all-inorganic perovskite solar cell is provided, comprising the following steps:

[0008] 1) Spin coating a mixed solution of bis(pentafluorophenyl)zinc and tin oxide on a surface of a conductive substrate to form a dense film to obtain a doped tin oxide electron transport layer, and then coating the doped tin oxide electron transport layer with a zinc oxide solution to obtain an electron transport layer;

[0009] 2) preparing an all-inorganic perovskite photoactive layer on the surface of the electron transport layer film obtained in step 1);

[0010] 3) A hole transport layer and an anode electrode are sequentially prepared on the surface of the all-inorganic perovskite photoactive layer obtained in step 2) to obtain an all-inorganic perovskite solar cell.

[0011] As a third aspect of the present invention, an application of an all-inorganic perovskite solar cell in the photovoltaic field is provided.

[0012] Based on the above technical solution, the present invention provides an all-inorganic perovskite solar cell and its preparation method and application, which have at least one or part of the following beneficial effects:

[0013] The present invention provides an all-inorganic perovskite solar cell and a preparation method thereof. The invention comprises the following steps: di(pentafluorophenyl)zinc is doped and introduced into a tin oxide solution to prepare a doped tin oxide electron transport layer; and then a zinc oxide electron transport layer is spin-coated on the surface of the doped tin oxide electron transport layer, so that the Fermi level of the tin oxide is shifted upward to form an energy level that is more closely matched with the zinc oxide, thereby reducing energy loss at the interface between the two electron transport layers. Moreover, due to the doping of the di(pentafluorophenyl)zinc, the electron mobility of the tin oxide is improved, which promotes the transmission and extraction of carriers, thereby facilitating the reduction of energy loss between layers in the all-inorganic perovskite solar cell and improving the energy conversion efficiency of the all-inorganic perovskite solar cell.

[0014] The present invention provides a method for preparing an all-inorganic perovskite solar cell, which has a simple process, mild conditions and is easy to control.

[0015] The present invention provides an all-inorganic perovskite solar cell and a preparation method thereof. When a zinc oxide electron transport layer is spin-coated on the doped tin oxide electron transport layer as an electron transport layer, the energy level difference between the two layers is significantly reduced, achieving a photoelectric conversion efficiency of 16.73%, which is much higher than the all-inorganic perovskite solar cell (15.21%) of the tin oxide electron transport layer doped without di(pentafluorophenyl)zinc. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1Schematic diagram of the structure of the all-inorganic perovskite solar cell and the molecular structure of ZCF in an embodiment of the present invention;

[0017] Figure 2 is a graph showing the volt-ampere characteristic of all-inorganic perovskite solar cells prepared in the embodiments of the present invention and the comparative examples;

[0018] Figure 3 1 is an electron mobility graph of Example 3 of the present invention and Comparative Example 1;

[0019] Figure 4 This is the energy level arrangement diagram of the all-inorganic perovskite solar cell of Example 3 of the present invention and Comparative Example 1.

[0020] Description of the accompanying drawings: 1. Conductive substrate, 2. Tin oxide electron transport layer doped with bis(pentafluorophenyl)zinc, 3. Zinc oxide electron transport layer, 4. All-inorganic perovskite photoactive layer, 5. Hole transport layer, 6. Metal anode, 7. Metal cathode. DETAILED DESCRIPTION

[0021] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0022] In the process of realizing the present invention, it was found that how to reduce the energy loss between the layers in the all-inorganic perovskite solar cell is a technical difficulty in improving the energy conversion efficiency of the all-inorganic perovskite solar cell. The present invention introduces di(pentafluorophenyl)zinc (ZCF) into a tin oxide solution to prepare a tin oxide (ZCF@SnO2) solution containing ZCF, and uses the ZCF@SnO2 solution to prepare a doped tin oxide electron transport layer. The zinc oxide electron transport layer is spin-coated on the surface of the doped tin oxide electron transport layer, so that the Fermi level of tin oxide moves up, forming a more matching energy level with zinc oxide, reducing the energy loss at the interface, and improving the energy conversion efficiency of the all-inorganic perovskite solar cell.

[0023] It should be noted that some of the terms in this invention are defined as follows:

[0024] Work function: The minimum energy required to move an electron from the interior of a solid to the surface of the object.

[0025] Specifically, according to an embodiment of the present invention, an all-inorganic perovskite solar cell is provided, comprising: a conductive substrate, an electron transport layer, an all-inorganic perovskite photoactive layer, a hole transport layer, and an anode electrode stacked in sequence, wherein the electron transport layer comprises a doped tin oxide electron transport layer and a doped zinc oxide electron transport layer;

[0026] The doped tin oxide electron transport layer is obtained by ZCF doping;

[0027] The zinc oxide electron transport layer is spin-coated on the doped tin oxide electron transport layer.

[0028] According to an embodiment of the present invention, the electron transport layer formed by spin-coating the zinc oxide electron transport layer on the doped tin oxide electron transport layer is a double-layer electron transport layer.

[0029] According to an embodiment of the present invention, ZCF is doped into the tin oxide electron transport layer. ZCF causes the Fermi level of tin oxide to shift upward, forming a more matching energy level with the zinc oxide electron transport layer spin-coated on the doped tin oxide electron transport layer, thereby reducing the energy loss at the interface between the two electron transport layers. In addition, the addition of ZCF can also improve the electron mobility of tin oxide, promote the transport and extraction of carriers, and improve the film quality of the all-inorganic perovskite photoactive layer, which is beneficial to reducing the energy loss between the layers in the all-inorganic perovskite solar cell, thereby improving the overall power generation performance of the all-inorganic perovskite solar cell.

[0030] According to an embodiment of the present invention, the mass ratio of ZCF to tin oxide is 7-54:1000.

[0031] According to an embodiment of the present invention, the mass ratio of ZCF to tin oxide is set to 7-54:1000, which is more conducive to shifting the Fermi level of tin oxide upward and forming a more matching energy level with zinc oxide, thereby reducing non-radiative recombination losses and improving the electron mobility of tin oxide.

[0032] According to an embodiment of the present invention, the thickness of the electron transport layer is 30-40 nm, for example, 30 nm, 32 nm, 34 nm, 36 nm, 38 nm, or 40 nm.

[0033] According to an embodiment of the present invention, the thickness of the all-inorganic perovskite photoactive layer is 400-500 nm; the thickness of the hole transport layer is 150-190 nm; and the thickness of the anode electrode is 50-70 nm.

[0034] According to an embodiment of the present invention, the material used for the conductive substrate includes indium tin oxide conductive glass (ITO); the material used for the all-inorganic perovskite photoactive layer includes cesium lead iodine bromine perovskite (CsPbI 2.25 Br 0.75 ); the material used for the hole transport layer includes 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenylamine))9,9′-spirobifluorene (Spiro-OMeTAD); and the anode electrode material includes metallic gold.

[0035] According to an embodiment of the present invention, a method for producing an all-inorganic perovskite solar cell includes the following steps:

[0036] 1) Spin coating a ZCF@SnO2 solution on the surface of a conductive substrate to form a dense film to obtain a doped tin oxide electron transport layer, and then coating the doped tin oxide electron transport layer with a zinc oxide solution to obtain an electron transport layer;

[0037] 2) preparing an all-inorganic perovskite photoactive layer on the surface of the electron transport layer obtained in step 1);

[0038] 3) A hole transport layer and an anode electrode are sequentially prepared on the surface of the all-inorganic perovskite photoactive layer obtained in step 2) to obtain an all-inorganic perovskite solar cell.

[0039] According to an embodiment of the present invention, the conditions for spin-coating the ZCF@SnO2 solution on the surface of the conductive substrate in step 1) include: a spin-coating speed of 4500-5500 rpm, a spin-coating time of 25-35 seconds, and then annealing at 130-170°C for 25-35 minutes to obtain a tin oxide electron transport layer; the spin-coating speed of the zinc oxide solution covering the surface of the doped tin oxide electron transport layer is 4500-5500 rpm, the spin-coating time is 35-45 seconds, and after spin-coating, annealing at 210-220°C for 35-45 minutes to obtain an electron transport layer.

[0040] According to an embodiment of the present invention, the preparation method of the ZCF@SnO2 solution includes: mixing a tin oxide stock solution and deionized water in a volume ratio of 1:4 to obtain a tin oxide solution; adding ZCF to the tin oxide solution, stirring and dissolving, to obtain a tin oxide solution doped with ZCF, wherein the concentration of the ZCF@SnO2 solution is 1 to 8 mg / mL.

[0041] According to an embodiment of the present invention, if the concentration of the ZCF@SnO2 solution is too high, it is impossible to prepare a ZCF-doped tin oxide electron transport layer with a smooth surface. The surface of the electron transport layer is rough, which is not conducive to electron transport, affecting the preparation of the zinc oxide electron transport layer and the film quality of the all-inorganic perovskite photoactive layer, resulting in serious energy loss between the layers in the all-inorganic perovskite solar cell; if the concentration of the ZCF@SnO2 solution is too low, the Fermi level of tin oxide is not enough to form a more matching energy level with zinc oxide, and thus the energy loss at the interface between the doped tin oxide electron transport layer and the zinc oxide electron transport layer cannot be reduced. Therefore, the suitable concentration range of the ZCF@SnO2 solution is 1 to 8 mg / mL, preferably 4.5 to 5.5 mg / mL, for example, 4.5 mg / mL, 5 mg / mL, and 5.5 mg / mL.

[0042] According to an embodiment of the present invention, in step 2), preparing an all-inorganic perovskite photoactive layer on the surface of the electron transport layer obtained in step 1) includes: spin-coating an all-inorganic perovskite precursor solution onto the surface of the electron transport layer, including spin-coating the all-inorganic perovskite precursor solution at 450-550 rpm for 4-6 seconds and then switching to 2800-3000 rpm for 30-50 seconds, and annealing at 200-300°C for 9-11 minutes after spin coating to obtain the all-inorganic perovskite photoactive layer.

[0043] According to an embodiment of the present invention, an application of an all-inorganic perovskite solar cell in the photovoltaic field is also provided.

[0044] The chemicals and raw materials used in the following examples were all commercially available.

[0045] Preparation example: Preparation of an all-inorganic perovskite solar cell

[0046] Figure 1 Schematic diagram of the structure of the all-inorganic perovskite solar cell in an embodiment of the present invention and the molecular structure formula of ZCF.

[0047] like Figure 1 As shown, the present invention provides an all-inorganic perovskite solar cell, comprising: a conductive substrate 1, a ZCF-doped tin oxide electron transport layer 2, a zinc oxide electron transport layer 3, an all-inorganic perovskite photoactive layer 4, a hole transport layer 5, a metal anode 6, and a metal cathode 7. The doped tin oxide electron transport layer is modified by ZCF doping. The structure of ZCF is as follows: Figure 1 shown.

[0048] Specifically, ITO is used as the conductive substrate material, and CsPbI 2.25 Br 0.75 The all-inorganic perovskite solar cell is prepared using Spiro-OMeTAD as the hole transport layer material and gold (Au) as the anode material.

[0049] 1. Preparation of ZCF@SnO 2 solution

[0050] Take 1 mL of tin oxide stock solution and add 4 mL of deionized water and stir to obtain a tin oxide solution. Dissolve ZCF in the above tin oxide solution and stir to dissolve to obtain 5 mg / mL ZCF@SnO2.

[0051] 2. Preparation of electron transport layer on conductive substrate

[0052] After cleaning and drying the etched conductive substrate 1 (ITO) with a nitrogen gun, the substrate was placed in a UV ozone analyzer for 15 minutes. The substrate was then placed on the chuck of a spin coater and the filtered ZCF@SnO2 solution was dripped onto the ITO surface. The substrate was spin-coated at 5000 rpm for 30 seconds to form a dense ZCF-doped tin oxide film on the ITO. After spin coating, the substrate was annealed at 150°C in ambient air for 30 minutes to form the ZCF-doped tin oxide electron transport layer 2. After complete cooling, the substrate was placed in a UV ozone analyzer for another 5 minutes to improve the wettability of the ZCF-doped tin oxide film. The ZCF-doped tin oxide electron transport layer was then fully coated with zinc oxide solution and spin-coated at 5000 rpm for 40 seconds. The zinc oxide electron transport layer 3 was then annealed at 200°C for 40 minutes. Prior to fabricating the all-inorganic perovskite photoactive layer, the substrate on which the electron transport layer had been deposited was UV ozone treated for 10 minutes.

[0053] 3. Preparation of all-inorganic perovskite photoactive layer

[0054] Dissolve 285.8 mg of cesium iodide (CsI), 380.3 mg of lead iodide (PbI2), and 100.9 mg of lead bromide (PbBr2) in 1 mL of a 7:3 (volume ratio) dimethylformamide / dimethyl sulfoxide (DMF / DMSO) mixed solvent. Heat and stir at 60°C for 4 hours. Filter through a 0.45 μm organic filter to obtain a clear perovskite precursor solution before use. Apply 50 μL of this solution dropwise to the surface of the zinc oxide electron transport layer (3) prepared in step 2 above. Spin coat at 500 rpm for 5 seconds, then switch to 2900 rpm for 40 seconds. Anneal at 250°C for 10 minutes to obtain a dark reddish-brown all-inorganic perovskite film, forming the all-inorganic perovskite photoactive layer (4). The volume ratio of the DMF / DMSO mixed solvent is preferably 10:0 to 0:10, more preferably 9:1 to 6:4, and most preferably 7:3.

[0055] 4. Preparation of hole transport layer

[0056] Dissolve 73.2 mg of Spiro-OMeTAD in 1 mL of chlorobenzene, then add 28.8 μL of 4-tert-butylpyridine (tBP) and 18.8 μL of lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI) solution (520 mg of Li-TFSI dissolved in 1 mL of acetonitrile). After adding all the additives, stir overnight at room temperature to obtain the Spiro-OMeTAD solution. Quickly drop-coat 15 μL of the Spiro-OMeTAD solution onto the surface of the all-inorganic perovskite photoactive layer 4 prepared in step 3 above, then spin-coat at 3000 rpm for 30 seconds to obtain the hole transport layer 5.

[0057] 5. Preparation of Metal Electrodes

[0058] The substrate prepared in 2-3 above, which is spin-coated with a double-layer electron transport layer, a perovskite layer, and a hole transport layer, is placed in a vacuum coating machine to evaporate metal on the surface of the hole transport layer 5 to form a metal anode 6 and an ITO-evaporated metal cathode 7 to form an all-inorganic perovskite solar cell.

[0059] Example 1

[0060] The etched ITO was cleaned and dried with a nitrogen gun; UV ozone treatment was performed for 30 minutes before spin coating to clean the substrate surface and regulate the substrate work function.

[0061] Place the clean ITO on the suction cup of the spin coater, and apply a tin oxide solution doped with 1 mg / mL ZCF filtered through a 0.45 μm water filter membrane to the entire glass. Spin coat at 5000 rpm for 30 seconds, then heat and anneal on a hot plate at 150°C for 30 minutes.

[0062] After annealing, the substrate was treated with UV-ozone for 6 minutes, and then a 0.45 μm organic filtered zinc oxide solution was applied to completely cover the tin oxide substrate. The solution was spin-coated at 5000 rpm for 40 seconds, and then annealed at 200°C for 40 minutes.

[0063] Dissolve 285.8 mg of cesium iodide (CsI), 380.3 mg of lead iodide (PbI2), and 100.9 mg of lead bromide (PbBr2) in 1 mL of a 7:3 (volume ratio) DMF / DMSO mixture. Heat and stir at 60°C for 4 hours. Filter through a 0.45 μm organic filter to obtain a clear perovskite precursor solution before use. Apply 50 μL of the perovskite solution to a zinc oxide substrate and spin-coat at 500 rpm for 5 seconds, then at 2900 rpm for 40 seconds. Anneal at 250°C for 10 minutes to obtain a dark reddish-brown, all-inorganic perovskite film approximately 460 nm thick.

[0064] 15 μL of Spiro-OMeTAD solution was quickly drop-coated on the all-inorganic perovskite film, and then spin-coated at 3000 rpm for 30 seconds to obtain a hole transport layer of approximately 200 nm.

[0065] Finally, the substrate coated with the above film was placed in a vacuum coating machine 1.5×10 -4 Gold electrodes were evaporated under Pa, and the thickness of the gold electrodes was about 65 nm. The device structure was ITO / ZCF@SnO2 / ZnO / CsPbI 2.25 Br 0.75 (460nm) / Spiro-OMeTAD(200nm) / Au(65nm) all-free perovskite solar cells.

[0066] Example 2

[0067] The structure and preparation method of the all-inorganic perovskite solar cell are similar to those in Example 1, except that 3 mg / mL of ZCF@SnO2 is fully stirred and coated on the ITO substrate to obtain a ZCF-doped modified tin oxide electron transport layer.

[0068] Example 3

[0069] The structure and preparation method of the all-inorganic perovskite solar cell are similar to those in Example 1, except that 5 mg / mL of ZCF@SnO2 is fully stirred and coated on the ITO substrate to obtain a ZCF-doped modified tin oxide electron transport layer.

[0070] Example 4

[0071] The structure and preparation method of the all-inorganic perovskite solar cell are similar to those in Example 1, except that 8 mg / mL of ZCF@SnO2 is fully stirred and coated on the ITO substrate to obtain a ZCF-doped modified tin oxide electron transport layer.

[0072] Comparative Example 1

[0073] The structure and preparation method of the all-inorganic perovskite solar cell are similar to those of Example 1, except that the tin oxide electron transport layer is not doped with ZCF.

[0074] The all-inorganic perovskite solar cells prepared in Examples 1 to 4 and Comparative Example 1 were respectively subjected to an AM1.5G, 100 mW / cm 2 The performance of all-inorganic perovskite solar cells was tested under xenon lamp irradiation. The test parameters included open circuit voltage, short circuit current, fill factor and energy conversion efficiency, as shown in Table 1.

[0075] The battery performance test was carried out under the Oriel Sol 3A solar simulator, and the open circuit voltage (V OC ), short-circuit current (J SC ), fill factor (FF) and power conversion efficiency (PCE).

[0076] Table 1 Performance parameters of all-inorganic perovskite solar cells prepared in Examples and Comparative Examples

[0077]

[0078] Figure 2 2 is a graph showing the volt-ampere characteristic of the all-inorganic perovskite solar cells prepared in the embodiments and comparative examples of the present invention.

[0079] Combined with Table 1 and Figure 2It can be seen that the V OC , J SC and FF are increased, and finally the photoelectric conversion efficiency of the all-inorganic perovskite solar cell prepared by the present invention is increased from 15.21% to the champion efficiency of 16.73%, and the device performance is significantly improved.

[0080] In order to explore the reasons for the improved performance of all-inorganic perovskite solar cell devices, the present invention first studied the effect of ZCF on the electrical properties of tin oxide. By preparing devices with ITO / silver / tin oxide / silver structure and ITO / silver / ZCF@SnO2 / silver structure, cyclic voltammetry curve detection was performed to obtain the corresponding current-voltage curve, and then the Mott-Gurney formula (as shown in 1-1) was used to calculate the electron mobility before and after tin oxide doping.

[0081]

[0082] Where: J represents the current density;

[0083] ε is the dielectric constant of vacuum;

[0084] ε n represents the relative dielectric constant of tin oxide;

[0085] V represents voltage, and d is the thickness of tin oxide;

[0086] μ is the electron mobility of tin oxide.

[0087] Figure 3 3 is a comparison chart of the electron mobility of Example 3 of the present invention and Comparative Example 1.

[0088] like Figure 3 As shown in Figure 2, the electron mobility of the tin oxide electron transport layer after doping with ZCF is 5.88×10 -3 cm 2 V -1 s -1 The electron mobility of the undoped tin oxide electron transport layer is 4.02×10 -3 cm 2 V -1 s -1 It can be seen that the electron mobility of tin oxide in the tin oxide electron transport layer doped with ZCF is significantly improved, which will be beneficial to the extraction and transport of electrons in the tin oxide electron transport layer doped with ZCF, thus leading to J SC increase.

[0089] In order to further explore the reasons for the performance improvement of the formal all-inorganic perovskite solar cell device, the present invention also uses ultraviolet photoelectron spectroscopy to detect the all-inorganic perovskite solar cells prepared in Example 3 and Comparative Example 1 respectively.

[0090] Figure 4 This is the energy level arrangement diagram of the all-inorganic perovskite solar cell in the embodiment of the present invention. Figure 4 The portions having the same conduction band bottom in Example 3 and Comparative Example 1 are omitted.

[0091] like Figure 4 As shown in the figure, the mismatched energy levels between the conduction band bottom (-4.57 eV) of tin oxide (SnO2) in the tin oxide electron transport layer and the conduction band bottom (-3.64 eV) of zinc oxide (ZnO) in the zinc oxide electron transport layer severely limit the photovoltage output of all-inorganic perovskite solar cells, resulting in huge voltage loss. However, the conduction band bottom (-3.88 eV) of tin oxide in the tin oxide electron transport layer doped with ZCF (ZCF@SnO2) and ZnO (-3.64 eV) have a more matched energy level arrangement, indicating that ZCF makes the Fermi level of tin oxide move up, forming a more matched energy level with the zinc oxide in the zinc oxide electron transport layer spin-coated on the doped tin oxide electron transport layer, which can reduce the voltage loss to make V OC improvement.

[0092] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An all-inorganic perovskite solar cell, comprising: A conductive substrate, an electron transport layer, an all-inorganic perovskite photoactive layer, a hole transport layer and an anode electrode are stacked in sequence, wherein the electron transport layer is composed of a doped tin oxide electron transport layer and a zinc oxide electron transport layer; The doped tin oxide electron transport layer is obtained by doping with bis(pentafluorophenyl)zinc; The zinc oxide electron transport layer is spin-coated on the doped tin oxide electron transport layer; Wherein, the mass ratio of the bis(pentafluorophenyl)zinc to tin oxide is 7-54:1000.

2. The all-inorganic perovskite solar cell according to claim 1, characterized in that The thickness of the electron transport layer is 30-40 nm.

3. The all-inorganic perovskite solar cell according to claim 1, characterized in that The thickness of the all-inorganic perovskite photoactive layer is 400-500 nm; The thickness of the hole transport layer is 150-190 nm; The thickness of the anode electrode is 50-70 nm.

4. The all-inorganic perovskite solar cell according to claim 1, characterized in that The conductive substrate is made of indium tin oxide conductive glass; The material used in the all-inorganic perovskite photoactive layer includes cesium lead iodine bromine perovskite; The hole transport layer is made of materials including 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenylamine))9,9′-spirobifluorene; The anode electrode material includes metallic gold.

5. A method for preparing an all-inorganic perovskite solar cell according to any one of claims 1 to 4, comprising the following steps: 1) spin coating a mixed solution of bis(pentafluorophenyl)zinc and tin oxide on the surface of the conductive substrate and performing an annealing process to form a dense thin film to obtain a doped tin oxide electron transport layer, coating the doped tin oxide electron transport layer with the zinc oxide solution, and performing a spin coating process and an annealing process to obtain the zinc oxide electron transport layer; 2) preparing an all-inorganic perovskite photoactive layer on the surface of the zinc oxide electron transport layer film obtained in step 1); 3) A hole transport layer and an anode electrode are sequentially prepared on the surface of the all-inorganic perovskite photoactive layer obtained in step 2) to obtain an all-inorganic perovskite solar cell.

6. The preparation method according to claim 5, characterized in that The conditions for spin-coating the mixed solution of di(pentafluorophenyl)zinc and tin oxide on the surface of the conductive substrate in step 1) include: a spin coating speed of 4500-5500 rpm, a spin coating time of 25-35 seconds, and then annealing at 130-170°C for 25-35 minutes to obtain a tin oxide electron transport layer; the spin coating speed for coating the surface of the doped tin oxide electron transport layer with the zinc oxide solution is 4500-5500 rpm, a spin coating time of 35-45 seconds, and after spin coating, annealing at 210-220°C for 35-45 minutes to obtain a zinc oxide electron transport layer.

7. The preparation method according to claim 6, characterized in that The preparation method of the mixed solution of bis(pentafluorophenyl)zinc and tin oxide comprises: The tin oxide stock solution was mixed with deionized water in a volume ratio of 1:4 to obtain a tin oxide solution; Adding bis(pentafluorophenyl)zinc to the tin oxide solution, stirring and dissolving, to obtain a tin oxide solution doped with bis(pentafluorophenyl)zinc, wherein the concentration of the tin oxide solution of bis(pentafluorophenyl)zinc is 1-8 mg / mL.

8. The preparation method according to claim 5, characterized in that The step 2) of preparing the all-inorganic perovskite photoactive layer on the surface of the zinc oxide electron transport layer obtained in step 1) comprises: Spin coating the all-inorganic perovskite precursor solution onto the surface of the zinc oxide electron transport layer includes: first spin coating the all-inorganic perovskite precursor solution at 450-550 rpm for 5 seconds and then spin coating at 2800-3000 rpm for 30-50 seconds, and then annealing at 200-300° C. for 9-11 minutes after spin coating to obtain the all-inorganic perovskite photoactive layer.

9. Application of the all-inorganic perovskite solar cell according to any one of claims 1 to 8 in the photovoltaic field.

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