Preparation method of acid-modified SnO2 transport layer perovskite solar cells

Abstract

This invention relates to the field of perovskite solar cell materials technology, specifically a method for preparing acid-modified SnO2 transport layer perovskite solar cells. The method for preparing the SnO2 transport layer material includes: sequentially subjecting Sn(OH)4 to hydrothermal treatment, washing, drying, and calcination to obtain SnO2 nanoparticles; dispersing the SnO2 nanoparticles in a dispersant, and adjusting the pH of the system to 2-8 with acid to obtain the final product. This invention uses acid to regulate the pH value of SnO2 particles to prepare an electron transport layer material. This material can improve the energy level matching, conductivity, and surface quality of the electron transport layer, thereby enhancing the photoelectric conversion efficiency and stability of perovskite solar cells and meeting the industrial production requirements of large-area and flexible cells.

Description

Technical Field

[0001] This invention relates to the field of perovskite solar cell materials technology, specifically to a method for preparing an acid-modified SnO2 transport layer perovskite solar cell. Background Technology

[0002] Perovskite solar cells have attracted widespread attention in the photovoltaic field in recent years due to their high photoelectric conversion efficiency, low cost, and solution-based processing capabilities. Among them, the electron transport layer (ETL), as one of the key components of perovskite solar cells, has a significant impact on the performance and stability of the device. Tin dioxide (SnO2), due to its wide bandgap, excellent electron transport capability, and optical transparency, has been widely used in the electron transport layer of perovskite solar cells.

[0003] However, SnO2 particles prepared by traditional methods face numerous challenges in applications, particularly in terms of energy level matching, conductivity, surface defects, and particle uniformity, which limit further improvements in device performance. In recent years, researchers have employed various improvement methods to enhance the performance of the SnO2 electron transport layer, including metal ion doping, surface modification, and nanostructure manipulation. For example, metal doping can effectively improve the electron transport performance of SnO2, thereby increasing the efficiency of solar cells; surface modification significantly enhances device stability by reducing interface defect density. However, despite these improvements, traditional SnO2 particles still present several problems in practical industrial applications. First, insufficient energy level matching results in low electron transport efficiency between SnO2 and the perovskite layer, thus affecting the photoelectric conversion efficiency of the cell. Second, limited conductivity prevents SnO2 particles from effectively transporting electrons, increasing the internal resistance of the device. Surface defects are also a significant issue, as these defects easily lead to interfacial recombination, further reducing photoelectric performance. In addition, SnO2 particles are prone to aggregation during large-area coating, resulting in uneven film and thus affecting the overall stability and performance of the battery.

[0004] Therefore, there is an urgent need for a simple and effective way to improve the performance of SnO2 particles to meet the needs of industrial production of large-area and flexible perovskite solar cells. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for preparing perovskite solar cells with an acid-modified SnO2 transport layer. This invention uses acid to adjust the pH value of SnO2 particles to prepare the electron transport layer material. This material can improve the energy level matching, conductivity, and surface quality of the electron transport layer, thereby enhancing the photoelectric conversion efficiency and stability of perovskite solar cells and meeting the industrial production requirements of large-area and flexible cells.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing an acid-modified SnO2 transport layer material, comprising:

[0008] Sn(OH)4 was subjected to hydrothermal treatment, washing, drying and calcination in sequence to obtain SnO2 nanoparticles;

[0009] The SnO2 nanoparticles are dispersed in a dispersant, and the pH of the system is adjusted to 2-8 with acid to obtain the final product.

[0010] Preferably, the Sn(OH)4 is obtained by reacting tetravalent tin salt hydrate with a base. In some embodiments of the present invention, it can be obtained by reacting SnCl4·5H2O with a base, or by reacting SnCl2·2H2O with a base after oxidation.

[0011] Preferably, the hydrothermal treatment conditions are 150–180°C for 4–6 hours.

[0012] Preferably, the washing is performed until the solution is neutral.

[0013] Preferably, the roasting conditions are 400-500°C for 1-2 hours.

[0014] Preferably, the SnO2 nanoparticles are dispersed in a dispersant to prepare a 3-5 wt% SnO2 colloidal solution.

[0015] Preferably, the acid is selected from any one or more of hydrochloric acid, nitric acid, acetic acid, oxalic acid, phosphoric acid, sulfuric acid, citric acid, hydrofluoric acid, and polyacrylic acid. To precisely control the particle size, dispersibility, and surface chemical properties of SnO2 colloidal particles, the SnO2 colloidal particles are optimized based on the acid strength, chelating effect, and coordination characteristics of the acid, thereby enhancing their interfacial matching with the perovskite absorber layer.

[0016] In some embodiments of the present invention, the pH of the acid-adjusted system is any one of 2, 6, 7, 7.2, 7.3, 7.5, 8, or a value between two of them.

[0017] Secondly, the present invention provides an acid-modified SnO2 transport layer material prepared by the preparation method described above.

[0018] Thirdly, the present invention provides a perovskite solar cell, the structure of which includes a transparent conductive substrate, an electron transport layer, a perovskite light-absorbing layer, a hole transport layer, and a metal electrode layer, wherein the electron transport layer is prepared from the acid-modified SnO2 transport layer material.

[0019] The perovskite solar cell structures described in this invention include, but are not limited to, planar heterojunctions, mesoporous structures, and inverted structures.

[0020] Fourthly, the present invention provides a method for preparing a perovskite solar cell, comprising the following steps:

[0021] S1, Clean transparent conductive substrate;

[0022] S2. Preparation of the electron transport layer: The acid-modified SnO2 transport layer material is deposited on the transparent conductive substrate;

[0023] S3. Prepare a perovskite light-absorbing layer on the electron transport layer;

[0024] S4. A hole transport layer is prepared on the perovskite light-absorbing layer;

[0025] S5. Prepare a metal electrode layer on the hole transport layer.

[0026] Preferably, the transparent conductive substrate material is selected from any one of FTO (fluorine-doped tin oxide), ITO (indium tin oxide), flexible ITO / PEN (polyethylene terephthalate), AZO (aluminum-doped zinc oxide), and GZO (gallium-doped zinc oxide).

[0027] Preferably, in step S2, the acid-modified SnO2 transport layer material is deposited on a transparent conductive substrate by any of the following methods: spin coating, dip coating, spray coating, or blade coating.

[0028] Preferably, the deposition process in S2 requires annealing at 100-180°C for 30-60 minutes, resulting in an electron transport layer with a thickness of 30-50 nm. The specific thickness can be adjusted according to the device requirements.

[0029] Preferably, the material of the perovskite light-absorbing layer is selected from MAPbI. x Br y Cl 3-x-y ,FAPbI x Br y Cl 3-x-y CsPbI x BryCl 3-x-y CszFA1-zPbI x Br y Cl 3-x-y Cs z FA k MA 1-z-k PbI x Br y Cl 3-x-y (FAPbI3) x (MAPbBr3) 1-xOne or more of the following; where x = 0 to 3, y = 0 to 3, z = 0 to 3, and k = 0 to 3.

[0030] Preferably, step S3 specifically involves depositing a perovskite precursor solution onto the electron transport layer. This invention can employ a one-step, two-step, or multi-step deposition method, using any method such as spin coating, dip coating, spray coating, blade coating, evaporation, or atomic deposition to deposit the perovskite onto the electron transport layer. After annealing, a well-crystallized perovskite absorption layer is formed with a thickness of 50 nm to 1 μm, the specific thickness of which is adjusted according to light absorption requirements and device design.

[0031] Preferably, the hole transport layer material is selected from any one or more of organic materials, inorganic materials, and carbon materials, and has a thickness of 10nm to 500nm to optimize hole transport and interface matching.

[0032] Preferably, the organic material is selected from any one or more of Spiro-OMeTAD, PTAA, and P3HT.

[0033] Preferably, the inorganic material is selected from any one or more of NiOx, CuSCN, and CuI.

[0034] Preferably, the carbon material is graphene and / or carbon nanotubes.

[0035] Preferably, the metal electrode layer is deposited by methods such as thermal evaporation, electron beam evaporation, sputtering, or printing. The material can be any one of gold, silver, copper, aluminum, nickel, carbon-based materials and their alloys or composite materials to meet the comprehensive requirements of conductivity, stability and cost.

[0036] The beneficial effects of this invention are:

[0037] The core of this invention in preparing acid-modified SnO2 transport layer materials lies in precisely controlling the pH value of the SnO2 colloidal solution through acid regulation. This controls the particle size, dispersibility, and surface chemical properties of the SnO2 particles. Based on the acid strength, chelating effect, and coordination characteristics of the acid, the SnO2 colloidal particles are optimized to enhance their interfacial matching with the perovskite absorber layer. This method is simple, easy to implement, highly controllable, and applicable to various acid regulation strategies. Appropriate acid types and concentrations can be selected according to actual needs, exhibiting high adjustability and adaptability. This method requires no complex equipment or high-temperature, high-pressure conditions, making it easy to achieve industrial production with good repeatability and scalability.

[0038] This invention improves the energy level structure, conductivity, crystallinity, and surface quality of the electron transport layer in perovskite solar cell fabrication by precisely controlling the pH value of the SnO2 colloidal solution. This reduces interface states and surface defects, lowers non-radiative recombination losses, and achieves optimal energy level matching with the perovskite active layer, promoting efficient electron separation and transport. Consequently, it significantly enhances the device's open-circuit voltage, short-circuit current, and fill factor. Furthermore, the optimized SnO2 colloidal solution exhibits excellent dispersibility and stability, enabling uniform film formation on large-area and flexible substrates. The resulting film has a smooth, uniform surface and thickness, providing a reliable guarantee for large-scale coating processes.

[0039] The fabrication method and device structure of this invention are applicable to various perovskite solar cells, including planar heterojunctions, mesoporous structures, and inverted structures, and have broad application prospects. By adding an encapsulation layer or interface modification layer, the environmental stability of the device is further improved, its lifespan is extended, and it meets the requirements of practical applications. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the perovskite solar cell device structure.

[0041] Figure 2 This is the current density-voltage curve of the perovskite solar cell prepared in Example 1.

[0042] Figure 3 This is the current density-voltage curve of the perovskite solar cell prepared in Example 2.

[0043] Figure 4 This is the current density-voltage curve of the perovskite solar cell prepared in Example 3.

[0044] Figure 5 This is the current density-voltage curve of the perovskite solar cell prepared in Example 4.

[0045] Figure 6 This is the current density-voltage curve of the perovskite solar cell prepared in Example 5.

[0046] Figure 7 This is the current density-voltage curve of the perovskite solar cell prepared in Example 6.

[0047] Figure 8 This is the current density-voltage curve of the perovskite solar cell prepared in Example 7.

[0048] Figure 9 This is the current density-voltage curve of the perovskite solar cell prepared in Example 8.

[0049] Figure 10This is a test diagram of the maximum power tracking of light for the battery device in Example 4.

[0050] Figure 11 This is the X-ray photoelectron spectroscopy (XPS) spectrum of the SnO2 thin film in Example 4.

[0051] Figure 12 This is the ultraviolet photoelectron spectroscopy (UPS) spectrum of the SnO2 thin film in Example 4.

[0052] Figure 13 This is an atomic force microscope (AFM) image of the SnO2 thin film in Example 4.

[0053] Figure 14 This is the conductivity diagram of the SnO2 thin film in Example 4. Detailed Implementation

[0054] To enable those skilled in the art to better understand the technical solution of the invention, the invention will be further described in detail below with reference to specific embodiments.

[0055] Example 1

[0056] This embodiment provides a method for preparing an acid-modified SnO2 transport layer material:

[0057] 1.0 g of SnCl4·5H2O was dissolved in 50 mL of deionized water, and a 25%-28% ammonia solution was slowly added dropwise until the pH rose to 7, forming a white Sn(OH)4 precipitate. This precipitate was transferred to a 100 mL high-pressure reactor and hydrothermally treated at 150 °C for 4 hours to generate SnO2 nanoparticles. The SnO2 nanoparticles were washed with deionized water until neutral, dried at 60 °C, and calcined at 400 °C for 2 hours to obtain highly crystalline SnO2 nanoparticle powder. Then, an acid-controlled SnO2 colloidal solution was prepared. 0.3 g of the calcined SnO2 nanoparticle powder was dispersed in 10 mL of deionized water and ultrasonically dispersed for 30 minutes. Under stirring, 0.1 mL of a 1 M acetic acid solution was slowly added dropwise with continuous stirring to adjust the pH of the solution to 7.5. Finally, the solution was filtered through a 0.22 μm polytetrafluoroethylene (PTFE) filter membrane to remove possible aggregates and impurities, resulting in a homogeneous SnO2 colloidal solution.

[0058] This embodiment also provides a method for preparing perovskite solar cells from the acid-modified SnO2 transport layer material, the steps of which are as follows:

[0059] S1. Cleaning the transparent conductive substrate: Take an ITO conductive glass substrate with dimensions of 2.5cm × 2.5cm and perform ultrasonic cleaning. Immerse the substrate in deionized water containing approximately 2% detergent and ultrasonically clean for 15 minutes to remove surface oil and particulate matter. Then, thoroughly rinse the substrate with deionized water to ensure no detergent residue remains. Next, immerse the substrate in anhydrous ethanol and anhydrous isopropanol sequentially, ultrasonically cleaning for 10 minutes in each solvent to remove organic contaminants. After cleaning, dry the substrate surface with high-purity nitrogen and perform ultraviolet ozone treatment for 15 minutes to increase surface hydrophilicity and promote uniform deposition of subsequent thin films.

[0060] S2. Preparation of the electron transport layer: The SnO2 colloidal solution prepared above was dropped onto the cleaned ITO substrate and spin-coated at 3000 rpm for 30 seconds to ensure the uniformity and density of the film. The spin-coated substrate was pre-baked at 100°C for 10 minutes and then annealed at 150°C for 60 minutes to form a SnO2 electron transport layer with a thickness of about 50 nm.

[0061] S3. Preparation of the perovskite light-absorbing layer: 1.8 mmol of PbI2 (0.8298 g) and 1.8 mmol of CH3NH3I (0.2861 g) were dissolved in 1 mL of a mixed solvent of DMF and DMSO (volume ratio 8:1). The solution was stirred at 60 °C for 1 hour to obtain a clear perovskite precursor solution. After filtering the solution through a 0.45 μm filter membrane, it was deposited on the electron transport layer by a two-step spin coating method. The first step was spin coating at 1000 rpm for 10 seconds, and the second step was spin coating at 5000 rpm for 30 seconds. During the spin coating, 200 μL of chlorobenzene was added dropwise after 15 seconds to promote the rapid nucleation and growth of perovskite crystals. After spin coating, the substrate was annealed on a hot plate at 100 °C for 10 minutes to form a MAPbI3 perovskite light-absorbing layer with a thickness of about 500 nm.

[0062] S4. Preparation of the hole transport layer: 72.3 mg of Spiro-OMeTAD was dissolved in 1 mL of chlorobenzene, and 28.8 μL of tBP (4-tert-butylpyridine) and 17.5 μL of Li-TFSI (lithium bis(trifluoromethanesulfonylimide)) solution were added. After stirring at room temperature for 30 minutes, the solution was dropped onto the perovskite light-absorbing layer and spin-coated at 3000 rpm for 30 seconds to form a hole transport layer with a thickness of about 150 nm. Then, the device was placed in an environment with a relative humidity of about 20% and left to stand for 12 hours to allow Spiro-OMeTAD to undergo oxidation doping.

[0063] S5. Preparation of metal electrodes: The oxidized sample is fixed on the sample stage of the vacuum evaporation equipment, and the vacuum degree is reduced to better than 5×10⁻⁶. -4 Pa was used to deposit a 100 nm thick silver electrode using a thermal evaporation process. After cooling to room temperature, the sample was taken out for testing.

[0064] The device structure diagram of the obtained perovskite solar cell is shown below. Figure 1 As shown.

[0065] Example 2

[0066] This embodiment provides a method for preparing an acid-modified SnO2 transport layer material:

[0067] Dissolve 1.0 g of SnCl2·2H2O in 50 mL of deionized water to form a transparent Sn... 2+ Precursor solution. Under stirring, hydrogen peroxide (H₂O₂, 30%) was added dropwise to the solution until it turned a clear, pale yellow, indicating Sn. 2+ Oxidized to Sn 4+ A 1M NaOH solution was slowly added dropwise while continuously stirring and monitoring the pH value. When the pH value reached 8, a white Sn(OH)4 precipitate was formed. The precipitate was transferred to a 100 mL high-pressure reactor and hydrothermally treated at 180 °C for 6 hours to generate SnO2 nanoparticles with higher crystallinity. The SnO2 nanoparticles were washed with deionized water until neutral and dried at 60 °C to obtain SnO2 nanoparticle powder. The powder was calcined in air at 500 °C for 1 hour to improve the crystallinity and conductivity of SnO2. 0.5 g of the calcined SnO2 nanoparticle powder was dispersed in a mixed solvent of 10 mL of deionized water and anhydrous ethanol (volume ratio 1:1) to form a 5 wt% SnO2 colloidal solution. The solution was treated with ultrasound at 40 kHz for 60 minutes to ensure sufficient dispersion of the nanoparticles and the formation of a stable colloidal solution. Under stirring, 0.2 mL of 0.5 M oxalic acid solution was added slowly dropwise while continuously stirring, and the pH of the solution was adjusted to 7.2. Finally, the solution was filtered through a 0.45 μm polytetrafluoroethylene filter membrane to remove possible aggregates and impurities, yielding a homogeneous SnO2 colloidal solution.

[0068] This embodiment also provides a method for preparing perovskite solar cells from the acid-modified SnO2 transport layer material, the steps of which are as follows:

[0069] S1. Cleaning the transparent conductive substrate: The transparent conductive substrate is an FTO conductive glass substrate, and the cleaning method is the same as in Example 1.

[0070] S2. Preparation of the electron transport layer: The prepared SnO2 colloidal solution was dropped onto the cleaned FTO substrate and spin-coated at 4000 rpm for 20 seconds to ensure the uniformity and density of the film; the spin-coated substrate was placed on a hot plate and then annealed in air at 180°C for 60 minutes to form a SnO2 electron transport layer with a thickness of about 40 nm.

[0071] S3. Preparation of the perovskite light-absorbing layer: 1.5 mmol of lead iodide (PbI2, 0.693 g), 0.75 mmol of lead bromide (PbBr2, 0.275 g), 1.0 mmol of methylamine iodide (CH3NH3I, 0.159 g), and 0.5 mmol of methylamine bromide (CH3NH3Br, 0.056 g) were dissolved in 1 mL of a mixed solvent of γ-butyrolactone (GBL) and dimethyl sulfoxide (DMSO) (volume ratio 3:2). 40 μL of isopropanol solution of methylammonium chloride (MACl, 2 M) was added to improve the growth and stability of the perovskite crystals. The mixture was stirred at 70 °C for 2 hours until a clear and transparent perovskite precursor solution was formed. The precursor solution was filtered using a 0.22 μm PTFE membrane to remove insoluble matter. The precursor solution was then drop-coated onto the electron transport layer using a two-step spin-coating method: Step 1: Spin-coating at 500 rpm for 5 seconds to ensure uniform solution spread; Step 2: Spin-coating at 4000 rpm for 30 seconds to accelerate solvent evaporation and form a uniform precursor film. Ten seconds after the start of the second spin-coating step, 150 μL of diethyl ether was rapidly added to the center of the rotating substrate to promote rapid nucleation and growth of perovskite crystals, improving film quality. After spin-coating, the substrate was annealed on a hot plate at 100°C for 15 minutes to form a mixed halogen MAPb(I) film with a thickness of approximately 600 nm. 0.89 Br 0.11 )3 Perovskite light-absorbing layer.

[0072] S4. Preparation of the hole transport layer: Poly(trihexylthiophene) (P3HT) was used as the hole transport material. 10 mg of P3HT was dissolved in 1 mL of chloroform and stirred for 1 hour to form a 1 wt% P3HT solution. The P3HT solution was dropped onto the perovskite layer and spin-coated at 2000 rpm for 60 seconds to form a P3HT hole transport layer with a thickness of approximately 100 nm. The spin-coated substrate was then annealed on a hot plate at 80 °C for 10 minutes to improve the crystallinity and conductivity of P3HT.

[0073] S5. Preparation of metal electrodes: Same as in Example 1.

[0074] Example 3

[0075] This embodiment provides a method for preparing an acid-modified SnO2 transport layer material:

[0076] Same as Example 1, except that: when preparing the acid-controlled SnO2 colloidal solution, 0.05 mL of 1M nitric acid (HNO3) solution was added to the solution to adjust the pH value of the solution to 7.3.

[0077] This embodiment also provides a method for preparing perovskite solar cells from the acid-modified SnO2 transport layer material. The steps are the same as in Embodiment 1, except that the SnO2 colloidal solution prepared in this embodiment is used when preparing the electron transport layer.

[0078] Example 4

[0079] The preparation method for the acid-modified SnO2 transport layer material is the same as in Example 3.

[0080] This embodiment also provides a method for preparing perovskite solar cells from the acid-modified SnO2 transport layer material, the steps of which are as follows:

[0081] S1. Cleaning the transparent conductive substrate: Take a flexible ITO / PEN (polyethylene terephthalate) substrate with dimensions of 2.5cm × 2.5cm. Place the substrate in deionized water containing neutral detergent (approximately 2% detergent concentration) and ultrasonically clean for 10 minutes to remove surface oil and dust. Then, thoroughly rinse the substrate with deionized water until no detergent residue remains on the surface. Next, place the substrate in anhydrous ethanol and anhydrous isopropanol in sequence, ultrasonically cleaning for 10 minutes in each solvent to remove organic contaminants. Dry the substrate surface with high-purity nitrogen to prevent water residue. Place the substrate in an oxygen plasma cleaner for 15 minutes.

[0082] S2. Preparation of the electron transport layer: The prepared SnO2 colloidal solution was dropped onto the cleaned flexible ITO / PEN substrate and spin-coated at 3000 rpm for 40 seconds to ensure the uniformity and density of the film; the spin-coated substrate was placed on a hot plate at 100°C for annealing for 30 minutes to form a SnO2 electron transport layer with a thickness of about 30 nm.

[0083] The perovskite light-absorbing layer, hole transport layer, and metal electrode were prepared in the same manner as in Example 1.

[0084] Example 5

[0085] The preparation method for the acid-modified SnO2 transport layer material is the same as in Example 3.

[0086] This embodiment also provides a method for preparing perovskite solar cells from the acid-modified SnO2 transport layer material, the steps of which are as follows:

[0087] S1. Cleaning the Transparent Conductive Substrate: A 10cm × 10cm FTO (Fluorine-Doped Tin Oxide) conductive glass substrate is used to meet the needs of large-area fabrication. The substrate is placed in deionized water containing neutral detergent (2% dish soap) and ultrasonically cleaned for 30 minutes to remove surface oil and particulate matter. The substrate is then thoroughly rinsed with deionized water until no detergent residue remains. The substrate is then sequentially placed in anhydrous ethanol and anhydrous acetone, ultrasonically cleaned for 15 minutes in each solvent to remove organic contaminants. The substrate surface is dried with high-purity nitrogen to prevent water residue. Finally, the substrate is treated in a UV ozone cleaner for 30 minutes to increase surface hydrophilicity and promote uniform deposition of subsequent thin films.

[0088] S2. Preparation of the electron transport layer: SnO2 colloidal solution was uniformly coated onto a large-area FTO substrate using a blade coating method. The blade gap was set to 100 μm and the coating speed was 5 cm / s to ensure the uniformity and consistency of the film. The coated substrate was placed on a hot plate at 80°C and baked for 20 minutes to remove solvent residue. It was then annealed in air at 150°C for 60 minutes to form a SnO2 electron transport layer with a thickness of approximately 50 nm.

[0089] S3. Preparation of the perovskite light-absorbing layer: The perovskite precursor solution described in Example 1 was coated onto the SnO2 electron transport layer using the slot-die coating method. The slot gap was set to 50 μm, the coating speed was 10 mm / s, and the substrate temperature was controlled at 50 °C. The coated substrate was then placed on a hot plate at 100 °C for annealing for 30 minutes to form a uniform perovskite light-absorbing layer with a thickness of approximately 500 nm.

[0090] S4. Preparation of the hole transport layer: Same as in Example 1.

[0091] S5. Preparation of metal electrodes: Same as in Example 1.

[0092] Example 6

[0093] This embodiment provides a method for preparing an acid-modified SnO2 transport layer material:

[0094] Same as Example 1, except that: when preparing the acid-controlled SnO2 colloidal solution, 0.05 mL of 1M hydrochloric acid (HCl) solution was added to the solution to adjust the pH value of the solution to 2.0.

[0095] This embodiment also provides a method for preparing perovskite solar cells from the acid-modified SnO2 transport layer material. The steps are the same as in Embodiment 5, except that the SnO2 colloidal solution prepared in this embodiment is used when preparing the electron transport layer.

[0096] Example 7

[0097] This embodiment provides a method for preparing an acid-modified SnO2 transport layer material:

[0098] Same as Example 1, except that: when preparing the acid-controlled SnO2 colloidal solution, 0.05 mL of 1M phosphoric acid (H3PO4) solution was added to the solution to adjust the pH value of the solution to 8.0.

[0099] This embodiment also provides a method for preparing perovskite solar cells from the acid-modified SnO2 transport layer material. The steps are the same as in Embodiment 5, except that the SnO2 colloidal solution prepared in this embodiment is used when preparing the electron transport layer.

[0100] Example 8

[0101] This embodiment provides a method for preparing an acid-modified SnO2 transport layer material:

[0102] Same as Example 1, except that: when preparing the acid-controlled SnO2 colloidal solution, 0.05 mL of 1M polyacrylic acid (C5H2O) was added to the solution. 10 O2) solution, adjust the pH of the solution to 7.2.

[0103] This embodiment also provides a method for preparing perovskite solar cells from the acid-modified SnO2 transport layer material. The steps are the same as in Embodiment 5, except that the SnO2 colloidal solution prepared in this embodiment is used when preparing the electron transport layer.

[0104] Comparative Example 1

[0105] This comparative example provides a method for preparing an electron transport layer material:

[0106] Same as Example 1, except that the step of using acid to regulate the SnO2 colloidal solution was not used.

[0107] This comparative example also provides a method for preparing a perovskite solar cell from the electron transport layer material, with the same steps as in Example 1, except that the SnO2 prepared in this comparative example is used when preparing the electron transport layer.

[0108] Example 1: Battery Performance Test

[0109] The solar cells prepared in Examples 1-8 were subjected to performance testing under the following conditions: an AM1.5G solar simulator with a light intensity of 100 mW / cm². 2 The testing equipment was a Keithley 2400 source surface, and the effective area of ​​the active layer was 0.0625 cm². 2 .

[0110] The JV curves for Examples 1-8 and Comparative Example 1 are shown below. Figures 2-9 The data is shown in Table 1.

[0111] Table 1

[0112]

[0113] Depend on Figures 2-9 As can be seen from Table 1, compared with Comparative Example 1, the perovskite solar cells prepared by acid-controlled pH adjustment of SnO2 in the embodiments of the present invention show significant improvements in photoelectric performance indicators such as short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency. This indicates that the preparation method of the present invention can effectively improve the performance of perovskite solar cells. Among them, Example 4 is a method for preparing flexible cells, and Examples 5 to 8 are methods for preparing large-area cells, indicating that the method of the present invention can meet the industrial production needs of large-area and flexible cells.

[0114] Figure 10 The image shows the maximum power tracking (MPT) test results of the battery device prepared in Example 4. It can be seen that the perovskite solar cell prepared with the acid-controlled SnO2 colloidal solution of this invention still maintains 94.5% of its initial efficiency after 1200 hours of MPT testing, demonstrating the stability of the solar cell of this invention. In contrast, the solar cell prepared under the same conditions in Comparative Example 1 shows a significant decrease in both efficiency and stability.

[0115] Example 2: Performance Testing of SnO2 Thin Films

[0116] Figure 11 This is the X-ray photoelectron spectroscopy (XPS) spectrum of the electron transport layer (SnO2 thin film) prepared in Example 4. The figure shows the X-ray photoelectron spectroscopy (XPS) spectra of the untreated SnO2 nanoparticle powder of Comparative Example 1 (top image) and the SnO2 sample treated with acid in Example 4 (bottom image). By comparing the two spectra, the chemical changes caused by acid treatment can be analyzed. The O1s main peak in the XPS spectrum can be deconvoluted into multiple sub-peaks. These sub-peaks correspond to oxygen in different chemical states in the material. Comparing the binding energy positions of the top image (SnO2) and the bottom image (SnO2+HNO3), the shift in binding energy and the change in peak intensity can be observed. This indicates that the chemical environment of oxygen changed after HNO3 treatment. In the untreated SnO2, the main peak is located around 530 eV, which is usually attributed to lattice oxygen (O2). 2- After HNO3 treatment, new sub-peaks or increased intensity may appear in the 531-533 eV region, which may represent additional oxygen-containing groups such as surface hydroxyl groups or adsorbed water. Quantitative analysis of the sub-peak area can estimate the relative content of different oxygen species, thereby quantifying the impact of HNO3 treatment on the chemical environment of SnO2 surfaces.

[0117] Figure 12 The image shows the ultraviolet photoelectron spectroscopy (UPS) spectrum of the electron transport layer (SnO2 thin film) prepared in Example 4. It can be seen that, compared with Comparative Example 1, the work function of the SnO2 thin film prepared by the SnO2 colloidal solution after acid-controlled pH is significantly reduced, which is beneficial to energy level matching.

[0118] Figure 13 This is an atomic force microscope (AFM) image of the electron transport layer (SnO2 thin film) prepared in Example 4. It can be seen that, compared to Comparative Example 1, the roughness of the electron transport layer thin film obtained in this example is significantly reduced, which is more conducive to perovskite crystal growth.

[0119] Figure 14 The diagram shows the conductivity of the electron transport layer (SnO2 thin film) prepared in Example 4. It can be seen that, compared with Comparative Example 1, the conductivity of the SnO2 thin film prepared by the SnO2 colloidal solution after pH adjustment with acid is significantly improved, which is beneficial to the transport of charge carriers.

[0120] The above characterization results demonstrate that the method of the present invention can optimize the physicochemical properties of the SnO2 electron transport layer, improve its energy level matching, conductivity, crystallinity and surface quality, thereby enhancing the photoelectric conversion efficiency and stability of perovskite solar cells and meeting the industrial production needs of large-area and flexible cells.

[0121] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an acid-modified Sn02 transport layer material in a large-area or flexible perovskite solar cell, characterized in that, The application relates to an acid-modified SnO2 transmission layer material and a preparation method thereof. Sn(OH)4 is sequentially subjected to hydrothermal treatment, washing, drying and calcination to obtain SnO2 nanoparticles; The SnO2 nanoparticles are dispersed in a dispersant, and the pH of the system is adjusted to 7.2-7.5 by using an acid, so that the acid-modified SnO2 transmission layer material is obtained. The SnO2 nanoparticles are dispersed in a dispersant to prepare a 3-5wt% SnO2 colloidal solution. The acid is selected from any one or more of hydrochloric acid, nitric acid, acetic acid, oxalic acid, phosphoric acid, sulfuric acid, citric acid, hydrofluoric acid and polyacrylic acid.

2. An acid-modified SnO2 transmission layer material prepared by the preparation method in claim 1.

3. A perovskite solar cell, characterized by, The structure comprises a transparent conductive substrate, an electron transmission layer, a perovskite light absorption layer, a hole transmission layer and a metal electrode layer, wherein the electron transmission layer is prepared from the acid-modified SnO2 transmission layer material in claim 2.

4. A method for preparing a perovskite solar cell, characterized by, The method comprises the following steps: S1, cleaning a transparent conductive substrate; S2, preparation of an electron transmission layer: the acid-modified SnO2 transmission layer material in claim 2 is deposited on the transparent conductive substrate; S3, preparation of a perovskite light absorption layer on the electron transmission layer; S4, preparation of a hole transmission layer on the perovskite light absorption layer; S5, preparation of a metal electrode layer on the hole transmission layer.

5. The preparation method according to claim 4, characterized in that, The transparent conductive substrate material is selected from any one of FTO, ITO, flexible ITO / PEN, AZO and GZO.

6. The preparation method according to claim 4, characterized in that, The material of the perovskite light-absorbing layer is selected from one or more of MAPbI X Br y Cl 3-x-y , FAPbI x Br y Cl 3-x-y , CsPbI x Br y Cl 3-x-y , Cs z FA 1-z PbI x Br y Cl 3-x-y , Cs z FA k MA 1-z- k PbI x Br y Cl 3-x-y , (FAPbI3) x (MAPbBr3) 1-x ; wherein x = 0-3, y = 0-3, z = 0-3, k = 0-3.

7. The preparation method according to claim 4, characterized in that, The hole transmission layer material is selected from any one or more of organic materials, inorganic materials and carbon materials.

8. The preparation method according to claim 4, characterized in that, The metal electrode layer material is selected from any one of gold, silver, copper, aluminum, nickel, carbon-based materials and alloys or composite materials thereof.

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