Preparation method of nickel oxide thin film and perovskite solar cell

Abstract

The invention relates to a preparation method of a nickel oxide thin film and a perovskite solar cell, and the preparation method of the nickel oxide thin film comprises the steps: depositing NiO on a graphene layer or a nitrogen-doped graphene layer through magnetron sputtering, and obtaining the nickel oxide thin film, the preparation method of the perovskite solar cell comprises the following steps: firstly, preparing a graphene layer or a nitrogen-doped graphene layer on a substrate, and then depositing NiO through magnetron sputtering to obtain a nickel oxide film; and sequentially preparing a self-assembled monomolecular layer, a perovskite light absorption layer, an electron transport layer, a hole blocking layer and a back electrode on the nickel oxide thin film to obtain the perovskite solar cell. Compared with the prior art, the method has the advantages that the film quality comparable to that of an ALD method can be obtained within the thickness range of 3-15 nanometers, meanwhile, the cost and efficiency advantages of a magnetron sputtering method are achieved, and the method has wide industrial application prospects.

Description

Technical Field

[0001] This invention belongs to the field of optoelectronic functional thin films and semiconductor devices, and relates to a nickel oxide (NiO) x Methods for fabricating thin films and perovskite solar cells, particularly a method for preparing ultrathin, dense nickel oxide (NiO) using magnetron sputtering. x The method of thin film and its application as a hole transport layer in perovskite solar cells. Background Technology

[0002] Nickel oxide, as a p-type semiconductor material, has become an ideal hole transport layer (HTL) material in perovskite solar cells (PSCs), especially in inverted (pin) structure devices, due to its high hole mobility, well-matched band structure with the perovskite light-absorbing layer, and excellent chemical stability. A high-quality hole transport layer is crucial for cell performance, and ideal NiO... x -HTL needs to be ultra-thin, with a continuous, dense surface free of pinholes, and uniform thickness.

[0003] Currently, common methods for preparing nickel oxide thin films each have limitations: solution methods (such as sol-gel methods) are low in cost but the films are not dense enough and are prone to pinhole defects; traditional magnetron sputtering methods can obtain dense films, but when preparing ultrathin films below 10 nanometers, they are limited by the inherent island growth mode and it is difficult to ensure their continuity and uniformity; atomic layer deposition (ALD) can achieve the preparation of high-quality ultrathin films, but it has disadvantages such as expensive equipment, high precursor costs, and slow deposition rates, which restrict its industrial application.

[0004] Therefore, developing an alternative technology that can ensure the high quality of ultrathin nickel oxide films while also possessing low cost, high efficiency, and industrialization potential has become an urgent need in this field. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing nickel oxide thin films and perovskite solar cells, addressing the problems of high cost of the ALD method and poor film quality of traditional magnetron sputtering at ultrathin scales. This invention can achieve film quality comparable to the ALD method within a thickness range of 3-15 nanometers, while also possessing the cost and efficiency advantages of magnetron sputtering, thus demonstrating broad prospects for industrial application.

[0006] The objective of this invention can be achieved through the following technical solutions: The first aspect of the present invention provides a method for preparing a nickel oxide thin film, comprising: depositing NiO by magnetron sputtering on a graphene layer or a nitrogen-doped graphene layer, and annealing to obtain a nickel oxide thin film.

[0007] This invention first prepares an ultrathin layer of graphene or its derivative as an inducing layer on the surface of a conductive substrate, and then deposits a nickel oxide thin film on this layer using magnetron sputtering technology. The graphene or its derivative can effectively guide NiO. x Nucleation and growth of the material inhibits the island-like pattern and promotes the formation of continuous, dense, ultrathin composite structures.

[0008] The thickness of the nickel oxide film is 3-15 nm.

[0009] The first aspect of the present invention provides a method for preparing a perovskite solar cell, comprising: S1: Prepare a graphene layer or nitrogen-doped graphene layer on a substrate, then deposit NiO by magnetron sputtering and anneal to obtain a nickel oxide film; S2: A self-assembled monolayer, a perovskite light-absorbing layer, an electron transport layer, a hole-blocking layer, and a back electrode are sequentially prepared on a nickel oxide thin film to obtain a perovskite solar cell.

[0010] In some specific implementations, in step S1, conductive glass such as FTO or ITO is selected as the substrate and subjected to rigorous cleaning (such as ultrasonic cleaning with detergent, acetone, ethanol, and deionized water in sequence) and ultraviolet-ozone treatment to thoroughly remove surface organic matter and contaminants, and enhance the hydrophilicity and adhesion of the substrate surface.

[0011] In some specific embodiments, in step S1, the graphene layer or nitrogen-doped graphene layer is prepared by a blade coating method or a spin coating method.

[0012] In some specific embodiments, the coating method includes: coating a graphene dispersion or a nitrogen-doped graphene dispersion onto a substrate and then annealing it; The concentration of the graphene dispersion or nitrogen-doped graphene dispersion is 0.05-0.5 mg / mL; In the aforementioned coating process, the blade height is 50-60 μm, and the coating speed is 10-12 mm / s. During the annealing process, the annealing temperature is 100-120℃ and the annealing time is 30-60 minutes.

[0013] In some specific embodiments, the graphene dispersion or nitrogen-doped graphene dispersion is subjected to ultrasonic treatment for 5-15 minutes to ensure that the material is fully and uniformly dispersed without agglomeration.

[0014] In some specific embodiments, the spin coating method includes: spin coating a graphene dispersion or a nitrogen-doped graphene dispersion onto a substrate, followed by annealing; The concentration of the graphene dispersion or nitrogen-doped graphene dispersion is 0.1-0.2 mg / mL; The spin coating process includes: first spin coating at 500-1000 rpm for 10-15 seconds, and then spin coating at 2000-5000 rpm for 30-60 seconds. During the annealing process, the annealing temperature is 100-300℃ and the annealing time is 30-60 minutes.

[0015] In some specific embodiments, in step S1, the magnetron sputtering atmosphere is an inert gas, the magnetron sputtering pressure is 0.5-1.5 Pa, and the sputtering power is 80-150 W (RF). In the annealing process, the annealing temperature is 250-350℃ and the annealing time is 20-60min. Annealing is used to optimize the crystallinity and electrical properties of the film.

[0016] The thickness of the obtained nickel oxide film is 3-15 nm.

[0017] In some specific embodiments, in step S2, the method for preparing the self-assembled monolayer includes: coating an ethanol solution of Me-4PACz onto a nickel oxide film by blade coating or spin coating, followed by annealing; The concentration of the ethanol solution of Me-4PACz is 0.2-0.5 mg / mL; In the aforementioned coating process, the blade height is 50-60 μm, and the coating speed is 20-22 mm / s; In the spin coating process, the spin coating speed is 4000-4200 rpm and the spin coating time is 30-60 s; During the annealing process, the annealing temperature is 100-120℃ and the annealing time is 10-12 minutes.

[0018] In some specific embodiments, in step S2, the method for preparing the perovskite light-absorbing layer includes: using a mixture of dimethylformamide and dimethyl sulfoxide as a solvent, and cesium iodide, formamidinium iodide, lead iodide and methylamine chloride as solutes to prepare a precursor solution, which is then spin-coated or blade-coated onto a self-assembled monolayer to obtain an intermediate phase film, followed by annealing. The volume ratio of dimethylformamide to dimethyl sulfoxide is 4-5:1; The molar ratio of cesium iodide, formamidine iodide, lead iodide, and methylamine chloride is 0.05-0.1:0.95-1:1-1.05:0.12-0.15; The total concentration of cesium iodide, formamidine iodide, lead iodide, and methylamine chloride is 1.4-1.6 M; In the spin coating process, the spin coating speed is 1000-5000 rpm, and the spin coating time is 12-50 s; chlorobenzene is added during the spin coating process. In the scraping process, the scraper height is 150-200μm and the scraping speed is 50-100mm / s; and after scraping, the process includes treatment with chlorobenzene vapor for 10s. During the annealing process, the annealing temperature is 100-120℃ and the annealing time is 20-40 minutes.

[0019] In some specific embodiments, in step S2, the method for preparing the electron transport layer includes: mixing methyl [6,6]-phenyl-C61-butyrate and chlorobenzene to prepare a PCBM solution, then spin-coating it onto a perovskite light-absorbing layer, and annealing it to obtain the solution; The feeding ratio of methyl [6,6]-phenyl-C61-butyrate and chlorobenzene is 20 mg: 1 mL; In the spin coating process, the spin coating speed is 1000 rpm and the spin coating time is 30s; In the annealing process, the annealing temperature is 70°C and the annealing time is 10 minutes; or The method for preparing the electron transport layer includes: [the process is described in the original text, but the translation is incomplete and requires further context.] -4 C was obtained by evaporation at a rate of 0.5–0.6 Å / s under Pa conditions. 60 film.

[0020] In some specific embodiments, in step S2, the method for preparing the hole blocking layer includes: preparing a BCP solution by mixing copper bath and isopropanol, then spin-coating it onto the electron transport layer, and annealing it to obtain the solution; The ratio of copper sulfate and isopropanol in the feed mixture is 0.5 mg: 1 mL; In the spin coating process, the spin coating speed is 6000 rpm and the spin coating time is 30 s; In the annealing process, the annealing temperature is 70°C and the annealing time is 10 minutes; or The method for preparing the hole-blocking layer includes: [the process is described in the original text, but the translation is incomplete and requires further context.] -4 Under the condition of Pa, copper bath thin films were obtained by vapor deposition at a rate of 0.5-0.6 Å / s.

[0021] In some specific embodiments, the back electrode is prepared by depositing a copper electrode on the hole transport layer at a rate of 1 Å / s using a vacuum evaporation apparatus.

[0022] The resulting perovskite solar cell has an inverted (pin) structure.

[0023] The core of the present invention lies in: First, a ultrathin graphene or its derivative is prepared on a conductive substrate as an induction layer, and then nickel oxide is deposited by magnetron sputtering technology. This induction layer can effectively regulate the nucleation and growth kinetics of nickel oxide, overcoming the technical problem of film discontinuity and non-density caused by the island growth mode in the traditional magnetron sputtering at the ultrathin scale.

[0024] The present invention can achieve a continuous and dense nickel oxide thin film within the thickness range of 3 - 15 nm, breaking through the lower limit of the thickness for achieving a continuous film in the conventional magnetron sputtering process (about 20 nm). The prepared film has better light transmittance and lower cost. Using it as the hole transport layer of a perovskite solar cell helps to improve the photoelectric conversion efficiency of the device.

[0025] The process of the present invention has good repeatability and is compatible with the industrial production process, providing a reliable key material preparation technology for the industrialization of high-performance perovskite batteries.

[0026] Compared with the prior art, the present invention has the following beneficial effects: 1) Breaking through the limit of magnetron sputtering for preparing ultrathin dense films: By introducing ultrathin graphene as a nucleation induction layer, the initial growth behavior of NiO is effectively changed, making it transform from the traditional island growth to a layered growth mode, thus achieving the preparation of a high-quality film that is continuous, dense, and free of pinholes at an ultrathin thickness of 3 - 15 nanometers; x 2) Having significant cost and industrialization advantages: The present invention is based on the mature magnetron sputtering technology. The equipment cost and maintenance cost are much lower than those of ALD, and it has a high deposition rate, a wide process window, and good repeatability, being very suitable for large-area and continuous industrial production, providing a key material preparation solution for the industrialization of high-performance perovskite batteries; 3) Significantly improving the performance of perovskite solar cells: The ultrathin and dense NiO hole transport layer has excellent hole extraction ability and electron blocking effect, can effectively inhibit interface recombination, and reduce parasitic absorption and device series resistance. Applying it to a reverse perovskite solar cell can significantly improve the open-circuit voltage ([[ID=ID=16]] oc) and fill factor ( x ), thereby obtaining a higher photoelectric conversion efficiency (PCE). Examples show that the performance of the battery prepared by this method is significantly better than that of the comparative example without an induction layer, and the battery efficiency can reach more than 26.5%, and the module efficiency of 20 cm V oc) and fill factor ([[ID=ID=22]] FF ), thereby obtaining a higher photoelectric conversion efficiency (PCE). Examples show that the performance of the battery prepared by this method is significantly better than that of the comparative example without an induction layer, and the battery efficiency can reach more than 26.5%, and the module efficiency of 20 cm 2 components can reach more than 24%, belonging to the international top level. Brief Description of the Drawings

[0027] Figure 1 It is a schematic structural diagram of a perovskite solar cell in the present invention.

[0028] Explanation of markings in the diagram: 1-FTO substrate, 1-1-glass substrate, 1-2-FTO layer, 2-hole transport layer, 3-self-assembled monolayer, 4-perovskite light absorption layer, 5-electron transport layer, 6-hole blocking layer, 7-back electrode. Detailed Implementation

[0029] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0030] In the following embodiments, unless otherwise specified, the raw materials, reagents or processing techniques are all conventional commercial products or conventional processing techniques in the art.

[0031] The performance parameters of the perovskite solar cells in the following examples are obtained through AM1.5G (100 mW·cm). -2 The solar simulator and Keithley 2400 digital source meter from Wacom Denso Co., Japan were used to measure current-voltage curves. J - V The solar simulator was obtained by calibrating a standard silicon reference cell. J - V The voltage range measured by the curve is -0.2 V to 1.3 V.

[0032] Example 1: This embodiment provides a method for fabricating a perovskite solar cell, used to investigate the effect of magnetron sputtering of nickel oxide thin films with and without a graphene-inducing layer on improving the photovoltaic performance of the perovskite solar cell. It demonstrates that, at the ultrathin scale, this invention overcomes the limitations of magnetron sputtering of NiO. x The fundamental problem preventing the densification of thin films. The specific process includes the following steps: 1. NiO x Fabrication of hole transport layer 2: Substrate pretreatment: Using FTO conductive glass (1.8 cm × 2.4 cm) as the substrate, the substrate was ultrasonically cleaned with deionized water, acetone and ethanol in sequence, then dried with nitrogen in a dry air environment and subjected to ultraviolet ozone treatment; the ultraviolet light wavelength was 185 nm, the power was 2250 W and the irradiation time was 20 min to obtain FTO substrate 1.

[0033] Preparation of the inducing layer (in this example): A graphene dispersion (0.2 mg / mL, Sigma-Aldrich, 900448) was spin-coated onto an FTO substrate 1. The spin-coating parameters were: 800 rpm / 10 s for the first step and 3000 rpm / 40 s for the second step. Subsequently, it was annealed in air for 30 minutes on a 300°C hot stage (ASONE HPR4030).

[0034] NiO x Layer deposition: Place the above substrate into the vacuum chamber of the magnetron sputtering apparatus. Evacuate the base vacuum to below 5.0 × 10⁻⁶. -4 Pa. High-purity argon (Ar) gas was introduced at a flow rate of 45 sccm and a working pressure of 0.8 Pa. The NiO target was sputtered using a 100 W RF power supply for approximately 2 minutes, yielding a NiO layer approximately 8 nm thick. x Thin film. After deposition, the sample was annealed in air at 300°C for 30 minutes to optimize the crystallinity and electrical properties of the film.

[0035] Comparative Example (without graphene-induced layer): Under the exact same magnetron sputtering parameters, an approximately 8 nm thick NiO layer was directly deposited on the pretreated FTO substrate 1. x Thin film. After deposition, anneal in air at 300°C for 30 minutes.

[0036] 2. Fabrication of perovskite solar cells: Self-assembled monolayer 3: In the prepared NiO x An ethanol solution (0.5 mg / mL) of Me-4PACz was spin-coated onto hole transport layer 2 at 4000 rpm for 30 seconds and then annealed at 100°C for 10 minutes to form self-assembled monolayer 3 (SAM).

[0037] Perovskite light-absorbing layer 4: A perovskite solution with a total concentration of 1.4 M was prepared using a mixture of dimethylformamide and dimethyl sulfoxide as solvent (volume ratio = 4:1) and cesium iodide, formamidinium iodide, lead iodide, and methylamine chloride as solutes (molar ratio = 0.05:0.95:1.05:0.12). The perovskite solution was spin-coated onto the SAM layer at a speed of 1000 rpm for 12 s, and then the speed was increased to 5000 rpm for 38 s. During the 38th-40th s of the total spin-coating time, 150 μL of chlorobenzene was rapidly added dropwise onto the precursor film to obtain an intermediate phase film. The perovskite intermediate phase was annealed in a nitrogen glove box under a nitrogen atmosphere at 100 °C for 20 min to obtain perovskite light-absorbing layer 4 with a thickness of approximately 600 nm. Electron transport layer 5: 20 mg of methyl [6,6]-phenyl-C61-butyrate (PCBM) and 1 mL of chlorobenzene were prepared into a PCBM solution, which was then spin-coated onto the perovskite light absorption layer 4 at a speed of 1000 rpm for 30 s. After annealing in air at 70 °C for 10 min, an electron transport layer 5 with a thickness of about 40 nm was obtained. Hole blocking layer 6: Prepare a BCP solution by mixing 0.5 mg of copper bath (BCP) and 1 mL of isopropanol, and then spin-coat it onto electron transport layer 5 at a speed of 6000 rpm for 30 s. Anneal at 70 ℃ for 10 min to obtain a hole blocking layer 6 with a thickness of about 8 nm.

[0038] Back electrode 7: A 90 nm copper electrode was deposited on hole transport layer 2 using a vacuum evaporation apparatus at a speed of 1 Å / s.

[0039] Based on the above steps, perovskite solar cells were prepared, and their performance parameters are shown in Table 1.

[0040] Table 1. Area of ​​graphene-induced layer (0.06 cm²) with or without graphene 2 Perovskite solar cell performance parameters in, J SC Short-circuit current density; V OC : Open-circuit voltage; FF: Fill factor; Eff.: Photovoltaic conversion efficiency of perovskite solar cells.

[0041] Performance Comparison: The battery prepared in Example 1 showed improvements in photoelectric conversion efficiency (PCE), short-circuit current (...). J The graphene-induced layer significantly outperforms the comparative example in terms of sc), open-circuit voltage (Voc), and fill factor (FF), demonstrating its effectiveness in enhancing the performance of ultrathin NiO. x The key role of film quality.

[0042] Example 2: This embodiment aims to demonstrate the application of the method of the present invention on large-area substrates, and focuses on verifying that by introducing a graphene derivative—a nitrogen-doped graphene-induced layer—it can significantly reduce NiO while ensuring the compactness of the film. x The thickness of the hole transport layer improves the photoelectric performance of the perovskite solar cell module. A key difference between this embodiment and the comparative example is that the comparative example uses the minimum thickness (approximately 20 nm) achievable with conventional magnetron sputtering to fairly demonstrate the advantages of the "ultra-thin and dense" technology of this invention.

[0043] 1. NiO xPreparation of hole transport layer 2 Substrate pretreatment: Using FTO conductive glass (6 cm × 6 cm) as substrate 1, ultrasonic cleaning was performed sequentially with acetone, ethanol, and deionized water. Subsequently, it was dried with nitrogen in a dry air environment and subjected to ultraviolet ozone treatment. The ultraviolet light wavelength was 185 nm, the power was 2250 W, and the irradiation time was 20 min to clean and activate the substrate surface, thus obtaining FTO substrate 1.

[0044] Preparation of the Induced Layer (Example): A nitrogen-doped graphene (Aladdin, G139802) induced layer was prepared on an FTO substrate 1 using a blade coating method. The coating parameters were: blade distance from the substrate 50 μm, coating speed 10 mm / s. The concentration of the dispersion used was 0.1 mg / mL. After film formation, the sample was annealed in air at 100°C for 40 minutes to remove solvent and stabilize the film structure.

[0045] P1 Laser Scribing: On the above substrate, the FTO layer 1-2 is laser scribing performed for the first time to expose the glass substrate 1-1 and define the battery sub-cell. Figure 1 ).

[0046] NiO x Layer deposition: The substrate with the induced layer prepared above is placed in the vacuum chamber of a magnetron sputtering instrument. The base vacuum is evacuated to below 5.0 × 10⁻⁶. -4 After Pa, Ar gas (45 sccm) was introduced, and the working pressure was stabilized at 0.8 Pa. High-purity NiO ceramic target was sputtered using an RF power supply (100 W) for approximately 2 minutes, ultimately obtaining a NiO layer with a thickness of approximately 8 nm. x Thin film. After deposition, the sample was annealed in air at 300°C for 30 minutes to optimize the crystallinity and electrical properties of the film.

[0047] Comparative Example (No Induced Layer): For a fair comparison, the following comparative example was set up: On the same FTO substrate 1, without preparing any induced layer, magnetron sputtering was performed directly. To achieve the minimum thickness required for continuous and dense films under conventional magnetron sputtering processes, the deposition time was extended to approximately 6 minutes. Other sputtering parameters (working pressure, sputtering power, annealing conditions, etc.) were exactly the same as in the example, ultimately obtaining a NiO film with a thickness of approximately 20 nm. x Thin film. This comparative example represents the thickness limitations faced by existing technologies in achieving a reliable hole transport layer.

[0048] 2. Fabrication of perovskite solar cell modules Self-assembled monolayer 3 (SAM): throughout NiO xAn ethanol solution (0.2 mg / mL) of Me-4PACz was coated onto the surface using the following parameters: blade height 50 μm and coating speed 20 mm / s. The surface was then annealed at 100 °C for 10 minutes.

[0049] Perovskite light-absorbing layer 4: The perovskite layer was prepared using a blade coating method. The same perovskite precursor solution formulation as in Example 1 was used (CsI:FAI:PbI2:MACl, molar ratio = 0.05:0.95:1.05:0.12). The blade coating parameters were: blade height 150 μm, blade coating speed 50 mm / s. After film formation, chlorobenzene vapor was rapidly introduced into the coated area for 10 seconds, followed by annealing at 100°C for 20 minutes in a nitrogen atmosphere to form a perovskite light-absorbing layer 4 approximately 600 nm thick.

[0050] Electron transport layer 5: C was prepared using a vacuum thermal evaporation method. 60 Electron transport layer. In vacuum conditions below 5.0 × 10⁻⁶. -4 Under the condition of Pa, a C layer of approximately 20 nm thickness was deposited at a rate of 0.5 Å / s. 60 film.

[0051] Hole blocking layer 6: deposited using a vacuum thermal evaporation method on C 60 A copper bath (BCP) film of approximately 8 nm thickness was then deposited on the layer.

[0052] P2 laser scribing: Perform a second laser scribing to expose the underlying FTO conductive layer.

[0053] Back electrode 7 fabrication: A copper electrode approximately 90 nm thick was deposited on the device surface by vacuum evaporation.

[0054] P3 laser scribing: Perform a third laser scribing to cut open the back electrode 7 and expose the hole blocking layer 6.

[0055] like Figure 1 As shown, laser scribing lines P1, P2, and P3 are sequentially staggered laterally. The first laser scribing patternes the FTO, making certain areas non-conductive. The second laser scribing patternes the perovskite light-absorbing layer 4, electron transport layer 5, and hole transport layer 2, allowing the electrodes to enter the pattern formed by the second laser during electrode deposition, thus achieving series connection of the positive and negative electrodes of each sub-cell. The third laser scribing patternes the electrodes, realizing the final assembly.

[0056] 3. Performance Testing and Result Analysis The fabricated perovskite solar cell module (effective area 20.3 cm²) 2 Under standard test conditions (AM 1.5G, 100 mW / cm²), 2The initial performance parameters are shown in Table 2. After storing the unencapsulated component in air for one month, its performance was tested again to evaluate the initial stability, and the results are shown in Table 3.

[0057] Table 2. Comparison of initial performance of large-area perovskite solar cell modules (effective area: 20.3 cm²) 2 ) Table 3 Performance parameters after one week of storage under nitrogen atmosphere Performance comparison analysis: Test results show that the approximately 8 nm ultrathin dense NiO prepared using a nitrogen-doped graphene-induced layer... x The thin film, and the corresponding battery module, significantly outperforms the approximately 20 nm thick NiO layer in terms of power conversion efficiency (PCE), short-circuit current (Jsc), open-circuit voltage (Voc), and fill factor (FF). x Comparative examples of thin films. This result strongly demonstrates that the induced layer technology of this invention not only successfully overcomes the densification bottleneck of traditional magnetron sputtering at ultrathin scales, but also significantly improves performance by reducing photoparasitic absorption and electrical series resistance due to the achievement of a thinner, higher-quality hole transport layer. No significant differences were observed between the two groups of devices in stability tests, indicating that this invention does not sacrifice device reliability while improving performance.

[0058] Example 3: This embodiment aims to verify that when the method of the present invention is applied, the graphene or its derivative induction layer itself has no effect on improving the photoelectric performance of the perovskite solar cell module. This proves that the performance improvement observed in Experiments 1-2 originates from the ultrathin, dense nickel oxide deposited on the induction layer, rather than the induction layer material itself.

[0059] 1. FTO conductive substrate treatment Substrate pretreatment: Using FTO conductive glass (6 cm × 6 cm) as the substrate, ultrasonic cleaning was performed sequentially with detergent, acetone, ethanol, and deionized water. Then, ultraviolet-ozone treatment was performed for 10 minutes to clean and activate the substrate surface, resulting in FTO substrate 1.

[0060] Preparation of the inducing layer (Example of the invention): A graphene inducing layer was prepared on a pretreated FTO substrate 1 using a blade coating method. The coating parameters were: blade distance from the substrate 50 μm, coating speed 10 mm / s. The concentration of the dispersion used was 0.1 mg / mL. After film formation, the sample was annealed on a 100°C hot plate for 40 minutes to remove solvent and stabilize the film structure.

[0061] P1 Laser Scribing: The first laser scribing is performed on the substrate with the induced layer prepared above to define the battery sub-cell.

[0062] Comparative Example 1 (Nitrogen-doped graphene-induced layer): On the same FTO substrate 1, a nitrogen-doped graphene-induced layer was prepared using the same method, and then P1 laser scribing was performed.

[0063] Comparative Example 2 (without induction layer): On the same FTO substrate 1, without preparing any induction layer, P1 laser scribing was performed directly.

[0064] 2. Fabrication of perovskite solar cell modules SAM: An ethanol solution (0.2 mg / mL) of Me-4PACz was coated onto the above substrate using the following parameters: blade height 50 μm, coating speed 20 mm / s. The substrate was then annealed at 100 °C for 10 minutes.

[0065] Perovskite light-absorbing layer 4: The perovskite layer was prepared using a blade coating method. The same perovskite precursor solution formulation as in Example 1 was used (CsI:FAI:PbI2:MACl, molar ratio = 0.05:0.95:1.05:0.12). The blade coating parameters were: blade height 150 μm, blade coating speed 50 mm / s. After film formation, chlorobenzene vapor was rapidly introduced into the coated area for 10 seconds, followed by annealing at 100°C for 20 minutes in a nitrogen atmosphere to form a perovskite layer approximately 600 nm thick.

[0066] Electron transport layer 5: C was prepared using a vacuum thermal evaporation method. 60 Electron transport layer. In vacuum conditions below 5.0 × 10⁻⁶. -4 Under the condition of Pa, a C layer of approximately 20 nm thickness was deposited at a rate of 0.5 Å / s. 60 film.

[0067] Hole blocking layer 6: deposited using a vacuum thermal evaporation method on C 60 A copper bath (BCP) film of approximately 8 nm thickness was then deposited on the layer.

[0068] P2 laser scribing: Perform a second laser scribing to expose the underlying FTO conductive layer.

[0069] Back electrode 7 fabrication: A copper electrode approximately 90 nm thick was deposited on the device surface by vacuum evaporation.

[0070] P3 laser scribing: Perform the third laser scribing to cut open the back electrode 7.

[0071] 3. Performance Testing and Result Analysis The fabricated perovskite solar cell module (effective area 20.3 cm²) 2Under standard test conditions (AM 1.5G, 100 mW / cm²), 2 The initial performance parameters under ( ) are shown in Table 5.

[0072] Table 5. Comparison of initial performance of large-area perovskite solar cell modules (effective area: 20.3 cm²) 2 ) Performance comparison analysis: Test results show that battery modules containing graphene induction layers or nitrogen-doped graphene induction layers did not exhibit significant improvements in key performance parameters such as power conversion efficiency (PCE), short-circuit current (Jsc), open-circuit voltage (Voc), and fill factor (FF) compared to modules without induction layers. This confirms that the induction layer itself does not contribute to battery performance. Combined with Examples 1-2, it is clear that the improvement in the photoelectric performance of perovskite solar cells should be attributed to the ultrathin, dense nickel oxide deposited on the induction layer, rather than the induction layer material itself.

[0073] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for producing a nickel oxide thin film, characterized by, Comprise: Depositing NiO on the graphene layer or nitrogen-doped graphene layer by magnetron sputtering to obtain a nickel oxide film.

2. A method for preparing a perovskite solar cell, characterized by, Comprise: S1: preparing a graphene layer or nitrogen-doped graphene layer on a substrate, and then depositing NiO by magnetron sputtering to obtain a nickel oxide film as a hole transport layer (2); S2: sequentially preparing a self-assembled monolayer (3), a perovskite light absorption layer (4), an electron transport layer (5), a hole blocking layer (6), and a back electrode (7) on the nickel oxide film to obtain a perovskite solar cell.

3. The method for preparing a perovskite solar cell according to claim 2, characterized in that, In step S1, the graphene layer or nitrogen-doped graphene layer is prepared by a scraping method or a spin coating method.

4. The method for preparing a perovskite solar cell according to claim 3, characterized in that, The scraping method comprises: scraping a graphene dispersion liquid or a nitrogen-doped graphene dispersion liquid on a substrate, and annealing to obtain a graphene layer or a nitrogen-doped graphene layer; The concentration of the graphene dispersion liquid or the nitrogen-doped graphene dispersion liquid is 0.1-0.2 mg / mL; In the scraping, the scraper height is 50-60 μm, and the scraping speed is 10-12 mm / s, In the annealing, the annealing temperature is 100-120℃, and the annealing time is 30-60 min. 5.The method of claim 3, wherein the perovskite solar cell is prepared by the steps of: The spin coating method comprises: spin coating a graphene dispersion liquid or a nitrogen-doped graphene dispersion liquid on a substrate, and annealing to obtain a graphene layer or a nitrogen-doped graphene layer; The concentration of the graphene dispersion liquid or the nitrogen-doped graphene dispersion liquid is 0.05-0.5 mg / mL; The spin coating comprises: first spin coating at 500-1000 rpm for 10-15 s, and then spin coating at 2000-5000 rpm for 30-60 s; In the annealing, the annealing temperature is 100-300℃, and the annealing time is 30-60 min. 6.The method of claim 2, wherein the perovskite solar cell is prepared by the steps of: In step S1, in the magnetron sputtering, the magnetron sputtering atmosphere is an inert gas, the magnetron sputtering pressure is 0.5-1.5 Pa, and the sputtering power is 80-150 W (RF); In the annealing, the annealing temperature is 250-350℃, and the annealing time is 20-60 min.

7. The method for preparing a perovskite solar cell according to claim 2, characterized in that, In step S2, the preparation method of the self-assembled monolayer comprises: coating an ethanol solution of Me-4PACz on the nickel oxide film by scraping or spin coating, and annealing to obtain; The concentration of the ethanol solution of Me-4PACz is 0.2-0.5 mg / mL; In the scraping, the scraper height is 50-60 μm, and the scraping speed is 20-22 mm / s; In the spin coating, the spin coating speed is 4000-4200 rpm, and the spin coating time is 30-60 s; In the annealing, the annealing temperature is 100-120℃, and the annealing time is 10-12 min.

8. The method for preparing a perovskite solar cell according to claim 2, characterized in that, In step S2, the preparation method of the perovskite light absorption layer (4) comprises: using a mixture of dimethylformamide and dimethyl sulfoxide as a solvent, using cesium iodide, formamidinium iodide, lead iodide, and methylamine chloride as solutes to prepare a precursor solution, spin coating or scraping on the self-assembled monolayer to obtain an intermediate phase film, and annealing to obtain; The volume ratio of the dimethylformamide and the dimethyl sulfoxide is 4-5:1; The molar ratio of the cesium iodide, the formamidinium iodide, the lead iodide, and the methylamine chloride is 0.05-0.1:0.95-1:1-1.05:0.12-0.15; The total concentration of the cesium iodide, formamidinium iodide, lead iodide, and methylamine chloride is 1.4-1.6M; In the spin coating, the spin coating speed is 1000-5000 rpm, and the spin coating time is 12-50 s; and chlorobenzene is added during the spin coating, In the blade coating, the doctor blade height is 150-200 μm, and the blade coating speed is 50-100 mm / s; and after the blade coating, the device is further treated with chlorobenzene vapor for 10 s; In the annealing, the annealing temperature is 100-120℃, and the annealing time is 20-40 min.

9. The method for preparing a perovskite solar cell according to claim 2, characterized in that, In step S2, the preparation method of the electron transport layer (5) comprises the following steps: mixing [6,6]-phenyl-C61-butyric acid methyl ester and chlorobenzene to prepare a PCBM solution, spin coating the PCBM solution on the perovskite light absorption layer (4), and annealing to obtain the electron transport layer (5). The feeding ratio of the [6,6]-phenyl-C61-butyric acid methyl ester and chlorobenzene is 20 mg:1 mL. In the spin coating, the spin coating speed is 1000 rpm, and the spin coating time is 30 s. In the annealing, the annealing temperature is 70℃, and the annealing time is 10 min; or The method for preparing the electron transport layer (5) comprises: evaporating C -4 at a rate of 0.5-0.6 Å / s under the condition that the vacuum degree is less than 5.0-6.0 × 10 60 thin film. 10.The method of claim 2, wherein the perovskite solar cell is prepared by the steps of: In step S2, the preparation method of the hole blocking layer (6) comprises the following steps: mixing bathocuproine and isopropanol to prepare a BCP solution, spin coating the BCP solution on the electron transport layer (5), and annealing to obtain the hole blocking layer (6). The feeding ratio of the bathocuproine and isopropanol is 0.5 mg:1 mL. In the spin coating, the spin coating speed is 6000 rpm, and the spin coating time is 30 s. In the annealing, the annealing temperature is 70℃, and the annealing time is 10 min; or The method for preparing the hole blocking layer (6) comprises: evaporating a bathophenanthroline film at a rate of 0.5-0.6 Å / s under the condition that the vacuum degree is less than 5.0-6.0 × 10 -4 Pa.

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