Preparation Method of Perovskite Photovoltaic Cell

Abstract

The present application relates to a preparation method of a perovskite photovoltaic cell, which is suitable for being disposed on an external substrate and includes the following steps: The substrate serves as a support structure of the solar cell, and a transparent conductive substrate is deposited thereon; A hole transport layer is prepared on the transparent conductive substrate; The preparation and treatment of the perovskite material are carried out, and a perovskite precursor solution is prepared by using a mixed solvent system of dimethyl sulfoxide, 2-methyltetrahydrofuran and acetonitrile; The perovskite precursor material is coated on the hole transport layer to form a perovskite light absorption layer; An electron transport material is deposited on the perovskite light absorption layer to form an electron transport layer; A hole blocking layer is prepared on the electron transport layer, and finally a back electrode is deposited on the hole blocking layer; The organic unity of high-performance preparation and green manufacturing is realized.

Description

Technical Field

[0001] The present invention discloses a technology related to perovskite photovoltaic cells, and relates to a preparation method of a perovskite photovoltaic cell. Background Art

[0002] Solution printing has attracted wide attention in the high-throughput production of thin-film semiconductor electronic devices due to its inherent advantages such as simple manufacturing process, low cost, and large preparation area. Among them, perovskite materials have become a disruptive candidate material in photovoltaic technology due to their excellent optoelectronic properties. However, lead in perovskite precursors and traditional solvents such as N,N-dimethylformamide, N-methylpyrrolidone, and ethylene glycol methyl ether have adverse effects on the environment. Summary of the Invention

[0003] In view of this, the present application provides a preparation method of a perovskite photovoltaic cell to establish a solvent system that is both environmentally friendly and meets performance requirements.

[0004] According to one aspect of the present application, there is provided a preparation method of a perovskite photovoltaic cell, which is suitable for being disposed on an external substrate, and includes the following steps: Step 1: Deposit a transparent conductive substrate on the substrate, and the external substrate is a support structure of the perovskite photovoltaic cell; Step 2: Prepare a hole transport layer on the transparent conductive substrate; Step 3: Prepare a perovskite precursor solution using a mixed solvent of dimethyl sulfoxide, 2-methyltetrahydrofuran, and acetonitrile; Step 4: Coat the perovskite precursor solution on the hole transport layer to form a perovskite light absorption layer; Step 5: Deposit an electron transport material on the perovskite light absorption layer to form an electron transport layer; Step 6: Prepare a hole blocking layer on the electron transport layer; Step 7: Deposit a back electrode on the hole blocking layer.

[0005] According to one aspect of the present application, the volume fraction of dimethyl sulfoxide is 1% - 20%, the volume fraction of 2-methyltetrahydrofuran is 70% - 90%, and the volume fraction of acetonitrile is 1% - 20%.

[0006] According to one aspect of the present application, the volume ratio among dimethyl sulfoxide, 2-methyltetrahydrofuran, and acetonitrile is 1:8:1.

[0007] According to one aspect of the present application, dimethyl sulfoxide, 2-methyltetrahydrofuran, and acetonitrile are fully dissolved by magnetic stirring to prepare a perovskite precursor.

[0008] According to one aspect of the present application, the perovskite precursor solution is deposited on the hole transport layer by slot coating and annealed at 150°C for 10 minutes.

[0009] According to one aspect of the present application, the substrate is a glass substrate, and one of indium tin oxide thin film and fluorine-doped tin oxide thin film is deposited on the glass substrate to form a transparent conductive substrate; a nickel oxide thin film is deposited on the conductive substrate by spin coating or magnetron sputtering to form the hole transport layer.

[0010] According to one aspect of the present application, a fullerene layer is deposited on the perovskite active layer by thermal evaporation or spin coating to form the electron transport layer.

[0011] According to one aspect of the present application, a bathocuproine layer is deposited on the electron transport layer by thermal evaporation or spin coating to form the electron transport layer.

[0012] According to one aspect of the present application, a bathocuproine layer is deposited on the electron transport layer by thermal evaporation or spin coating to form the hole blocking layer.

[0013] According to one aspect of the present application, a metal electrode is deposited on the hole blocking layer to form the back electrode, and the material of the back electrode is silver or copper.

[0014] The beneficial effects of the present invention: By using dimethyl sulfoxide as the main solvent, its strong polarity and high coordination ability can not only effectively dissolve precursor materials such as PbI2 and MAI, but also stabilize the colloidal solution through the coordination effect of Pb 2+ with the S=O group, inhibiting the aggregation of colloidal particles. Thereby improving the film stability and consistency. 2-Methyltetrahydrofuran is used as the core green solvent, and its low toxicity and high volatility increase the upper limit of the coating rate, promote the rapid evaporation of the solvent, reduce the residual solvent in the film, accelerate the drying speed, and at the same time its low surface tension significantly improves the rheological properties of the solution, ensuring that the solution spreads evenly on the substrate surface, effectively avoiding coating film defects. Acetonitrile is used as the dynamic regulation solvent, and its relatively high saturated vapor pressure can form a complementary evaporation kinetic curve with 2-methyltetrahydrofuran, realizing the organic unity of high-performance preparation and green manufacturing. Description of the Drawings

[0015] Figure 1 It is a structural diagram of a photovoltaic cell with a perovskite film in this embodiment;

[0016] Figure 2 It is a diagram of the donor number and saturated vapor pressure of common perovskite solvents;

[0017] Figure 3 It is a comparison diagram of the macroscopic uniformity of perovskite films prepared by traditional solvents and the solvent system of this embodiment;

[0018] Figure 4 It is a scanning electron microscope comparison diagram of perovskite films prepared by high-speed blade coating under traditional solvents and the solvent system of this embodiment;

[0019] Figure 5 It is a comparison chart of the film thickness uniformity of perovskite films under different solvent systems;

[0020] Figure 6 It is a J-V curve chart of large-area perovskite modules prepared by blade coating under different solvent systems;

[0021] Figure 7 It is a domestic toxicity description chart of common perovskite solvents. Specific Embodiments

[0022] The following embodiments are provided to better further understand the present invention. It is not limited to the described optimal embodiment, and does not limit the content and protection scope of the present invention. Any product that is the same as or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other existing technologies falls within the protection scope of the present invention.

[0023] For those embodiments where specific experimental steps or conditions are not indicated, the operations or conditions of the conventional experimental steps described in the literature in this field can be followed. For the reagents or instruments whose manufacturers are not indicated, they are all conventional reagent products that can be obtained through commercial purchase.

[0024] As Figures 1 to 7 shown, the present application provides a method for preparing a perovskite photovoltaic cell, and the perovskite photovoltaic cell is suitable for being disposed on an external substrate, including the following steps: Step 1: The substrate serves as a support structure for the solar cell, and a transparent conductive substrate ① is deposited thereon; Step 2: A hole transport layer ② is prepared on the transparent conductive substrate ①; Step 3: The perovskite material is prepared and processed, and a perovskite precursor solution is prepared by using a mixed solvent system of dimethyl sulfoxide, 2-methyltetrahydrofuran, and acetonitrile; Step 4: The perovskite precursor material is coated on the hole transport layer ② to form a perovskite light absorption layer ③; Step 5: An electron transport material is deposited on the perovskite light absorption layer ③ to form an electron transport layer; Step 6: A hole blocking layer ⑤ is prepared on the electron transport layer, and finally a back electrode ⑥ is deposited on the hole blocking layer ⑤.

[0025] As Figure 1As shown, the substrate serves as the support structure of the perovskite photovoltaic cell, and a transparent conductive substrate ① is deposited thereon, which is used as the electrode material for subsequent charge collection and transportation. A hole transport layer ② is prepared on the transparent conductive substrate ① to help holes be effectively transported from the perovskite light absorption layer ③ to the electrode. Then, the perovskite material is prepared and processed, and a perovskite precursor solution is prepared using a mixed solvent system of dimethyl sulfoxide, 2-methyltetrahydrofuran, and acetonitrile. The perovskite precursor material is coated on the hole transport layer ② to form the perovskite light absorption layer ③. An electron transport material is deposited on the perovskite light absorption layer ③ to form an electron transport layer ④, which helps electrons transport from the perovskite light absorption layer ③ to the electrode layer. Then, a hole blocking layer ⑤ is prepared on the electron transport layer ④ to protect the perovskite light absorption layer ③ and the electron transport layer ④ and improve the efficiency of charge collection. Finally, a back electrode ⑥ is deposited as the top electrode during the entire solar cell, and the fabricated perovskite photovoltaic cell is encapsulated and tested. Encapsulation can prevent the influence of environmental conditions on the device performance, such as changes in light and humidity. The performance of the encapsulated perovskite photovoltaic cell also needs to be tested, including the power conversion efficiency (PCE), short-circuit current density (J sc ), open-circuit voltage (V oc ), and fill factor (FF) to evaluate the power conversion efficiency and stability during the period.

[0026] According to one aspect of the present application, the volume fraction of dimethyl sulfoxide is 1% - 20%, the volume fraction of 2-methyltetrahydrofuran is 70% - 90%, and the volume fraction of acetonitrile is 1% - 20%. The volume ratio among dimethyl sulfoxide, 2-methyltetrahydrofuran, and acetonitrile is 1:8:1. Dimethyl sulfoxide, 2-methyltetrahydrofuran, and acetonitrile are fully dissolved by magnetic stirring to prepare the perovskite precursor. The perovskite precursor solution is deposited on the hole transport layer ② by slot coating and annealed at 150 °C for 10 min.

[0027] The volume ratio among dimethyl sulfoxide, 2-methyltetrahydrofuran, and acetonitrile is 1:8:1. They are fully dissolved by magnetic stirring to obtain the perovskite precursor. Using the slot coating printing technique, the precursor is uniformly printed on the hole transport layer ② at a speed of 50 mm / s, and the distance between the coating head and the substrate is maintained at 80 μm to form a perovskite thin film. Subsequently, the wet film is flash-evaporated in a vacuum environment (vacuum degree lower than 20 Pa) for 60 s, and then annealed at 150 °C for 10 min to complete the entire growth process of the perovskite thin film.

[0028] According to one aspect of the present application, the substrate is a glass substrate. One of indium tin oxide thin film and fluorine-doped tin oxide thin film is deposited on the glass substrate to form a transparent conductive substrate ①; nickel oxide thin film is deposited on the conductive substrate ① by spin coating or magnetron sputtering to form a hole transport layer ②. A fullerene layer is deposited on the perovskite active layer by thermal evaporation or spin coating to form an electron transport layer ④. A bathocuproine layer is deposited on the electron transport layer ④ by thermal evaporation or spin coating to form an electron transport layer ④. A bathocuproine layer is deposited on the electron transport layer ④ by thermal evaporation or spin coating to form a hole blocking layer ⑤. A metal electrode is deposited on the hole blocking layer ⑤ to form a back electrode ⑥, and the material of the back electrode ⑥ is silver or copper.

[0029] Preferably, depositing the conductive substrate ① on the substrate further includes: the substrate is a glass substrate, and an ITO (indium tin oxide) or FTO (fluorine-doped tin oxide) thin film is deposited on the glass substrate to form a transparent conductive oxide (TCO) coating; preparing the hole transport layer ② on the TCO further includes: depositing NiO x (nickel oxide) thin film on the conductive substrate ①.

[0030] Secondly, preparing the electron transport layer ④ on the perovskite photoabsorbing layer ③ further includes: depositing a fullerene (C 60 or PCBM) layer on the active layer ③ by thermal evaporation or spin coating, which is used as an electron transport material to help electrons transport from the perovskite photoabsorbing layer ③ to the electrode layer.

[0031] Then, preparing the hole blocking layer ⑤ on the electron transport layer ④ further includes: depositing a bathocuproine (BCP) layer on the electron transport layer ④ by thermal evaporation or spin coating, which is used to protect the perovskite photoabsorbing layer ③ and the electron transport layer ④ and promote the charge collection efficiency.

[0032] Finally, preparing the back electrode ⑥ on the hole blocking layer ⑤ and encapsulating the perovskite thin film photovoltaic cell further includes: depositing a metal electrode on the hole blocking layer ⑤ to complete the preparation of the perovskite thin film photovoltaic cell, encapsulating the prepared solar cell, and performing performance tests on the encapsulated perovskite thin film photovoltaic cell.

[0033] In this embodiment, a metal electrode is deposited on the BCP layer as the top electrode of the entire perovskite thin film photovoltaic cell, and the metal electrode is silver or copper. The fabricated perovskite thin film photovoltaic cell is encapsulated to prevent the influence of environmental conditions on its performance, and performance tests are carried out on it, including PCE, J sc , V oc and FF, to evaluate the photoelectric conversion efficiency and stability of the device.

[0034] In an achievable manner, preparing a perovskite precursor solution includes: preparing a solution containing perovskite precursor substances AX and BX2, and the mixed solvent system of the perovskite precursor solution is dimethyl sulfoxide, 2-methyltetrahydrofuran, and acetonitrile; the A-site is composed of any one cation among cesium, rubidium, potassium, amino group, amidinium group, or alkali group, and the B-site is composed of any divalent metal cation among lead, tin, tungsten, copper, zinc, gallium, germanium, arsenic, selenium, rhodium, palladium, silver, cadmium, indium, antimony, osmium, iridium, platinum, gold, mercury, thallium, bismuth, polonium; the R-site is composed of any one of phenethylamine, 1,4-butanediamine, and guanidine group; the X-site is composed of any one anion among chlorine, bromine, iodine, thiocyanate, cyanide, oxycyanide, acetate, azide, borohydride, Co(CO) 4- , C(NO2) 3- , C(CN) 3- and the mixed solvent is DMSO, MeTHF, and ACN.

[0035] The examples are prepared by the same process method as the technical solution of this application. The perovskite solution uses a green solvent system, and the volume ratio of the solvent is adjustable. Mixed solvents with multi-dimensional gradients of DMSO:MeTHF:ACN volume ratios of 1:7:2, 1:8:1, 2:7:1, 1:9:0 (to verify the necessity of ACN), 0.5:8.5:1 (to fine-tune the main solvent ratio), and 1:7.5:1.5 (to further balance volatility and solubility) are respectively configured. Systematic experiments show that DMSO:MeTHF:ACN = 1:8:1 is the optimal mixed solvent system. In addition, if the environmental humidity is disturbed, the proportion of DMSO can be kept unchanged, and MeTHF:ACN can be further dynamically adjusted.

[0036] The prepared perovskite solution is deposited on the surface of the prepared hole transport layer ② by slot coating, where the coating speed of the slot coating method is 8 mm / s to 50 mm / s, preferably 30 mm / s.

[0037] First, vacuum film-forming treatment is carried out for 40 s, and then thermal annealing treatment is carried out. The treatment temperature is preferably 150 °C, and the treatment time is 10 min.

[0038] To illustrate the superiority of the preparation method of the perovskite photovoltaic cell of this application, the following comparative examples are now carried out:

[0039] The perovskite solution configured in the comparative example uses a conventional solvent system, and the volume ratio of the solvent is adjustable. A mixed solvent of DMF:NMP:2-Me (9:1:2) is preferably configured.

[0040] As Figure 1As shown, according to the "Occupational Exposure Limits for Hazardous Agents in the Workplace - Part 1: Chemical Hazardous Agents" issued by the National Health Commission of the People's Republic of China, the toxicity of DMSO, MeTHF, and ACN solvents is relatively lower than that of the commonly used perovskite preparation solvents DMF and NMP, meeting the "green" solvent standard and having no obvious toxicity and environmental burden.

[0041] As Figure 2 shown, although DMSO has a high similarity with DMF in solubility parameters, the synergistic effect of MeTHF and ACN significantly reduces the dynamic viscosity of the solution, optimizes the ink rheological properties, and thus improves the uniformity and controllability of the coating process. In addition, the high saturated vapor pressure characteristic of this green solvent accelerates the solvent evaporation rate, not only improving the coating speed, enhancing the production rhythm, but also reducing the diffusion phenomenon of perovskite colloidal particles on the substrate surface, avoiding the generation of defects such as pinholes and cracks. This improvement ensures the macroscopic uniformity and microscopic lattice consistency of the perovskite film, providing reliable technical support for the performance improvement and large-scale production of PV devices.

[0042] During the high-speed slot coating process, due to the low saturated vapor pressure and high solution viscosity of the traditional DMF / NMP / 2-Me solvent system, the solvent evaporation rate does not match the solute deposition rate. This kinetic imbalance causes the solution to flow non-uniformly on the transparent conductive substrate ①, and finally macro-defects such as ribs / stripes are locally formed on the surface of the perovskite film, as Figure 3 shown. In contrast, the green solvent system DMSO / MeTHF / ACN of this application has a high saturated vapor pressure and low viscosity, significantly improving the solvent evaporation efficiency and reducing the surface tension of the solution. These characteristics work together to promote the uniform and orderly deposition of the solute on the substrate surface, thus effectively avoiding the generation of the above-mentioned macro-defects and improving the film quality. Figure 4 Figure 12 is a scanning electron microscope (SEM) image of perovskite films prepared by the high-speed coating process under two different solvent systems. It can be seen from the figure that during high-speed blade coating, the perovskite film of the conventional solvent system is prone to generate a large number of holes, and the combination between grains is not tight enough. However, for the perovskite film of the green solvent system with high volatility of this application, the holes disappear, the grain size is larger, and the crystal quality is significantly improved. This may benefit from the dynamic regulation ability of CAN, indicating that optimizing the solvent system can improve the perovskite crystallization nucleation orientation and obtain high-quality perovskite films with larger grain size and less defect density.

[0043] Figure 5The comparison of the uniformity of perovskite films under conventional solvent systems and the green solvent system of the present application is shown. The film was deposited on a substrate of 1200 mm × 650 mm at a speed of 30 mm / s. First, the perovskite film was laser scribed, and then the thickness of the perovskite light-absorbing layer was measured by a profilometer. Nine data points evenly distributed on the entire substrate were selected, where the film thickness uniformity deviation = (maximum value - minimum value) / (2 * average value) * 100%. From Figure 5 it can be seen that there is over-etching during the laser scribing process. By comparing the conventional solvent and the green solvent of the present application, it can be found that the perovskite film thickness curve fluctuates greatly in the comparative example, the uniformity deviation is greater than ±5%, and the overall film thickness is uneven. In the example, the perovskite film under the green solvent has less fluctuation, indicating that it has more excellent film-forming characteristics under high-speed coating. The film thickness deviation is only 1.73%, and a more uniform perovskite film is obtained.

[0044] Table 1 Performance parameters of perovskite photovoltaic cells with two different solvent systems

[0045]

[0046] Figure 6 are the J-V curves of perovskite photovoltaic cells prepared using a conventional solvent and the green solvent with high volatility of the present application, respectively. The effective area of the module is 64.48 cm 2 , and the light intensity is AM1.5G 100 mW / cm 2 .

[0047] Table 1 shows the performance parameters of perovskite photovoltaic cells prepared under two solvent systems. It can be seen from Table 1 that all parameters of the perovskite photovoltaic cells prepared using the green solvent with high volatility of the present application have been significantly improved. Among them, the FF has the most obvious improvement, from 69.65% to 72.99%, and the PCE has increased from 14.34% to 16.51%.

[0048] It should be noted that although an environmentally friendly method for preparing large-area perovskite films and components is introduced by taking the present application as an example as above, those skilled in the art can understand that the present application should not be limited thereto. In fact, users can flexibly set each parameter according to personal preferences and / or actual application scenarios as long as the design is reasonable.

[0049] By the technical means of the present invention, due to the DMSO:MeTHF:ACN green solvent system, significant improvements have been achieved in the solubility and film-forming properties of perovskite. By further optimizing the coating process with the green solvent system, the use of harmful solvents in the production process has been effectively reduced, and the emission of toxic gases has been reduced, contributing to the large-scale industrial production of future photovoltaic cells with perovskite films and promoting the sustainable development of this field.

[0050] By carefully designing the solvent ratio combination, this application effectively synergizes the solubility, volatility, and surface tension characteristics of the three solvents, optimizing the solvent evaporation and film nucleation and crystallization mechanisms during the high-speed slot coating process.

[0051] Specifically, as the main solvent, DMSO's strong polarity and high coordination ability can not only effectively dissolve precursor materials such as PbI2 and MAI, but also stabilize the colloidal solution through the coordination effect between Pb 2+ and the S=O group, inhibiting the aggregation of colloidal particles. Thereby improving the film stability and consistency. As the core green solvent, MeTHF's low toxicity (LD50 > 2000mg / kg) and high volatility increase the upper limit of the coating rate, promoting the rapid evaporation of the solvent (the evaporation rate reaches 0.8μL / cm 2 ·s), reducing the residual solvent in the film and accelerating the drying speed. At the same time, its low surface tension (28mN / m) significantly improves the rheological properties of the solution, ensuring uniform spreading of the solution on the substrate surface and effectively avoiding coating film formation defects. As a dynamic regulation solvent, ACN with a relatively high saturated vapor pressure (kPa level) and MeTHF can form a complementary evaporation kinetic curve. In the initial stage of coating (generally 0-2s), the rapid evaporation of ACN dominates the rapid decrease in the liquid film thickness, avoiding the coffee ring effect caused by excessive solvent retention; in the later stage of coating (2-5s), the continuous evaporation of MeTHF and the slow release effect of DMSO synergistically regulate the crystallization kinetics, obtaining a dense film with a larger average grain size. Through the three-stage synergy mechanism of "strong dissolution - fast evaporation - stable crystallization", this solvent system not only improves the coating process efficiency by more than 2 times, but also effectively reduces the film defect density. At the same time, it reduces the solvent toxicity index (GHS classification) from Category 2 of the traditional system to Category 4, realizing the organic unity of high-performance preparation and green manufacturing. This invention ensures the high-quality deposition of perovskite films at a high-speed coating rate of 3m / min, thus guaranteeing the excellent optoelectronic performance of the device. The optimized solvent system not only breaks through the limitation of the coating speed, but also improves the component manufacturing yield. In addition, the green solvent system adopted in this invention reduces the use of toxic solvents, reduces environmental pollution, meets environmental protection standards, and thus improves the green preparation level of PSMs. After actual measurement, the efficiency of PSMs prepared by the solvent system of this invention has been increased from 14% to 16%, successfully realizing the uniform coating of large-area (1200mm×650mm) films, providing a feasible technical path for large-scale and high-efficiency production. Through this technical solution, PSMs have made significant breakthroughs in terms of green environmental protection, high-efficiency production, and performance improvement, with important technical value and broad application prospects.

[0052] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the scope disclosed by the present invention, according to the technical solution and its concept of the present invention, making equivalent substitutions or changes should be covered within the protection scope of the present invention.

Claims

1. A preparation method of a perovskite photovoltaic cell, characterized in that: The perovskite photovoltaic cell is suitable for being disposed on an external substrate, and includes the following steps: Step 1: Deposit a transparent conductive substrate on the substrate. The external substrate is a support structure of the perovskite photovoltaic cell; Step 2: Prepare a hole transport layer on the transparent conductive substrate; Step 3: Prepare a perovskite precursor solution by using a mixed solvent of dimethyl sulfoxide, 2-methyltetrahydrofuran and acetonitrile; Step 4: Coating the perovskite precursor solution on the hole transport layer to form a perovskite light absorption layer, and uniformly printing the perovskite precursor solution on the hole transport layer at a speed of 50 mm / s, keeping the distance between the coating head and the substrate at 80 μm. Subsequently, perform flash evaporation treatment on the perovskite precursor solution in a vacuum environment for a duration of 60 s, and anneal at 150 °C for 10 min; Step 5: Deposit an electron transport material on the perovskite light absorption layer to form an electron transport layer; Step 6: Prepare a hole blocking layer on the electron transport layer; Step 7: Deposit a back electrode on the hole blocking layer.

2. The preparation method of the perovskite photovoltaic cell according to claim 1, characterized in that, The volume fraction of the dimethyl sulfoxide is 1% - 20%, the volume fraction of the 2-methyltetrahydrofuran is 70% - 90%, and the volume fraction of the acetonitrile is 1% - 20%.

3. The preparation method of the perovskite photovoltaic cell according to claim 2, wherein, The volume ratio among the dimethyl sulfoxide, the 2-methyltetrahydrofuran and the acetonitrile is 1:8:

1.

4. The method for preparing a perovskite photovoltaic cell according to claim 3, wherein, The dimethyl sulfoxide, the 2-methyltetrahydrofuran and the acetonitrile are fully dissolved by magnetic stirring to obtain a perovskite precursor.

5. The preparation method of the perovskite photovoltaic cell according to claim 4, wherein: The substrate is a glass substrate, and one of indium tin oxide thin film and fluorine-doped tin oxide thin film is deposited on the glass substrate to form a transparent conductive substrate; Deposit a nickel oxide thin film on the conductive substrate by spin coating or magnetron sputtering to form the hole transport layer.

6. The preparation method of the perovskite photovoltaic cell according to claim 5, wherein: Deposit a fullerene layer on the perovskite active layer by thermal evaporation or spin coating to form the electron transport layer.

7. The method for preparing a perovskite photovoltaic cell according to claim 6, wherein: Deposit a bathocuproine layer on the electron transport layer by thermal evaporation or spin coating to form the hole blocking layer.

8. The preparation method of the perovskite photovoltaic cell according to claim 7, characterized in that: Deposit a metal electrode on the hole blocking layer to form the back electrode, and the material of the back electrode is silver or copper.

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