Method for optimizing performance of two-dimensional / three-dimensional tin-based perovskite solar cell by doping hydroxyethyl cellulose

Abstract

The invention belongs to the technical field of photovoltaics, and particularly relates to a method for optimizing the performance of a two-dimensional / three-dimensional tin-based perovskite solar cell by doping hydroxyethyl cellulose, which comprises the following steps: introducing hydroxyethyl cellulose as an additive into a perovskite precursor solution; the growth behavior of the crystal is effectively regulated and controlled in the crystallization process of the thin film by utilizing a macromolecular chain structure of a specific hydroxyethyl side chain cellulose skeleton and rich hydroxyl functional groups; the obtained perovskite solar cell is remarkably improved in the aspects of open-circuit voltage, short-circuit current density, filling factors and photoelectric conversion efficiency, and meanwhile, the perovskite solar cell has good stability; the invention provides a perovskite solar cell performance optimization strategy which is simple and convenient in process, environment-friendly and low in cost, and has a good application prospect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of photovoltaics, and particularly relates to a method for optimizing the performance of a two-dimensional / three-dimensional tin-based perovskite solar cell by doping with hydroxyethyl cellulose. BACKGROUND

[0002] As a new generation of photovoltaic technology, tin-based perovskite solar cells have become a research hotspot due to their environmental friendliness and excellent photoelectric properties. However, such cells still face problems such as easy oxidation of tin ions, difficulty in controlling the crystalline quality of thin films, and many interface defects, which seriously restrict their performance improvement and commercial application. In the prior art, researchers often introduce functional additives into the precursor solution to regulate the crystallization kinetics and interface properties, but the traditional method often cannot simultaneously solve the problems of oxidation stability and interface defects of tin-based perovskite. For example, although some additives can inhibit ion migration to a certain extent, they cannot effectively optimize the uniformity and carrier transport performance of the thin film. In addition, although the two-dimensional / three-dimensional heterostructure can enhance the stability, the precise control of the crystallization process still poses a challenge, resulting in significant loss of non-radiative recombination of carriers at the interface. Therefore, developing an additive strategy that can simultaneously inhibit tin oxidation, optimize crystalline quality, and passivate interface defects has become a key technical requirement for promoting the development of tin-based perovskite cells.

[0003] The perovskite layer is the core carrier of the photoelectric conversion process, responsible for absorbing sunlight and generating photo-generated electron-hole pairs. Its excellent light absorption coefficient and carrier diffusion length directly determine the upper limit of the energy conversion efficiency of the cell. Secondly, the chemical stability and crystalline quality of the layer have a decisive influence on the reliability of the device. Due to the easy oxidation of tin ions, the perovskite layer is prone to degradation under the action of water and oxygen, leading to performance decay. At the same time, defects such as pinholes and grain boundaries are easily generated during the crystallization of the thin film, which not only exacerbates carrier recombination, but also accelerates the interface decomposition reaction.

[0004] In view of the above technical problems, the present application proposes an innovative method by introducing hydroxyethyl cellulose into the perovskite precursor solution for in-situ doping. Hydroxyethyl cellulose is a non-ionic water-soluble polymer derived from cellulose. Cellulose itself is a high polymer connected by β-1,4 glycosidic bonds between glucose units, and each glucose unit has three hydroxyl groups (-OH) at C2, C3 and C6 positions. When it is used as a high molecular weight regulator, it can regulate the crystal growth kinetics through intermolecular interactions during crystallization, promoting the formation of a dense, uniform and low-defect two-dimensional / three-dimensional perovskite thin film. At the same time, its hydroxyl functional groups can inhibit the oxidation of divalent tin Sn 2+The modification strategy can also optimize the light absorption capacity of the perovskite layer and the surface energy of the thin film, and the surface hydrophobicity of the perovskite layer is adjusted, which helps to improve the interface compatibility and stability between the perovskite layer and the charge transport layer, and finally helps to realize a higher performance and more stable working lead-free perovskite solar cell. SUMMARY

[0005] The present application solves the above technical problems existing in the prior art, and provides a method for optimizing the performance of two-dimensional / three-dimensional tin-based perovskite solar cells by doping hydroxyethyl cellulose. By introducing hydroxyethyl cellulose into the perovskite precursor solution for in-situ doping, the crystallization behavior and photoelectric properties of the tin-based perovskite thin film are significantly optimized. The grain size of the doped thin film is significantly increased and more uniform, showing a highly dense and complete micro-morphology, effectively reducing the grain boundary hole and defect state density. The absorption capacity of the thin film in the visible light region is significantly enhanced, indicating an improved light trapping efficiency. The significant improvement of the device in short-circuit current density (Jsc) and fill factor (FF) indicates an improved carrier extraction and transport efficiency; the optimization of the dark current characteristics further confirms that the defect-assisted recombination is inhibited. The enhanced surface hydrophobicity of the thin film helps to improve the environmental stability of the device. The modification strategy realizes the synergistic improvement of the crystalline quality, interface contact and stability of the perovskite layer through the multiple effects of the polymer regulator, providing an effective way for the development of high-performance lead-free perovskite solar cells.

[0006] The technical scheme of the present application is as follows: A method for optimizing the performance of two-dimensional / three-dimensional tin-based perovskite solar cells by doping hydroxyethyl cellulose, comprising the following steps: S1, adding hydroxyethyl cellulose to a perovskite precursor solution to form a mixed solution; the perovskite precursor solution comprises tin iodide SnI2, formamidinium iodide FAI, phenethylammonium bromide PEABr, and tin fluoride; the concentration of hydroxyethyl cellulose in the mixed solution is 0.3-1.0 mg / mL; S2, depositing the mixed solution prepared in step S1 on a substrate and forming a two-dimensional / three-dimensional tin-based perovskite thin film doped with hydroxyethyl cellulose after annealing treatment.

[0007] Preferably, the mixed solution is a PEA 0.15 FA 0.85 SnI 2.85 Br 0.15 mixed solution with hydroxyethyl cellulose; wherein FA represents formamidinium ion (HC(NH2)2 + ), and PEA represents phenethylammonium ion (C6H5CH2CH2NH3 + ).

[0008] Preferably, the specific method of step S1 is as follows: dissolve tin iodide SnI2, formamidine iodide FAI, phenylethyl ammonium bromide PEABr, and tin fluoride in an organic solvent, then add hydroxyethyl cellulose solution, and mix and stir to obtain the mixed solution; the molar ratio of tin iodide SnI2, formamidine iodide FAI, phenylethyl ammonium bromide PEABr, and tin fluoride SnF is 1:0.85:0.15:0.1, and the total concentration of the mixed solution is 1.0 mol / L.

[0009] Preferably, the organic solvent is a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) solutions, wherein the volume ratio of DMF to DMSO is 4:1.

[0010] Preferably, in step S2, the mixed solution obtained in step S1 is deposited on a conductive glass substrate coated with a hole transport layer by spin coating; the spin coating parameters are preferably 5000 rpm for 36 seconds.

[0011] Preferably, in step S2, the annealing process is carried out at 70°C for 10 minutes.

[0012] A perovskite solar cell has a structure comprising a conductive glass layer, a hole transport layer, a perovskite absorber layer, an electron transport layer, a hole blocking layer, and a metal electrode stacked in sequence; wherein the perovskite absorber layer is prepared by the method described above.

[0013] Preferably, the hole transport layer material is PEDOT:PSS.

[0014] Preferably, the chemical composition of the perovskite absorber layer is hydroxyethyl cellulose-doped PEA. 0.15 FA 0.85 SnI 2.85 Br 0.15 .

[0015] Preferably, the electron transport layer material is PCBM.

[0016] Preferably, the hole-blocking layer material is BCP.

[0017] Preferably, the metal electrode is a silver electrode.

[0018] Preferably, the conductive glass layer is ITO conductive glass.

[0019] A method for fabricating a perovskite solar cell includes the following steps: D1, spin-coating a hole transport layer onto ITO conductive glass; D2, Preparation of perovskite absorber layer on hole transport layer: spin-coating perovskite precursor solution doped with hydroxyethyl cellulose onto the surface of hole transport layer, adding 150 μL of chlorobenzene as antisolvent at 13 seconds during spin-coating, and annealing after spin-coating. D3, spin-coat an electron transport layer onto the perovskite absorber layer for 30 seconds, followed by annealing; D4, a hole blocking layer is prepared on the electron transport layer using a vapor deposition process; D5, silver electrodes are deposited on the hole blocking layer to complete the battery fabrication.

[0020] Compared with the prior art, the advantages of the present invention are as follows: For the first time, hydroxyethyl cellulose (HEC) was introduced as a crystallization regulator into the perovskite precursor solution. Its abundant hydroxyl groups can coordinate with tin ions, effectively inhibiting Sn²⁺ oxidation, reducing internal defects in the film, and significantly improving the phase purity and crystallization order of the two-dimensional / three-dimensional mixed tin-based perovskite. HEC can regulate the nucleation and growth process of perovskite crystals through intermolecular forces, optimizing the aggregated structure of the two-dimensional and three-dimensional phases, and promoting the formation of a uniformly sized and fully covered perovskite light-absorbing layer. Simultaneously, its hydrophilicity improves the spreadability of the solution on the substrate, enhancing the quality of the film preparation. The introduction of HEC also passivates defects on the surface and at grain boundaries of the perovskite film, suppressing non-radiative recombination and enhancing carrier transport and collection efficiency. The resulting perovskite solar cells show significant improvements in open-circuit voltage, short-circuit current density, fill factor, and photoelectric conversion efficiency, while also exhibiting good stability.

[0021] Hydroxyethyl cellulose, as a green and biodegradable polymer material, possesses characteristics such as wide availability, low cost, and environmental friendliness. Its application in perovskite solar cells not only improves the photoelectric conversion efficiency and operational stability of the devices but also meets the needs of sustainable material development, demonstrating promising prospects for industrial application. Therefore, this invention provides a simple, environmentally friendly, and low-cost strategy for optimizing the performance of perovskite solar cells, with excellent application prospects. Attached Figure Description

[0022] Figure 1 This is a structural diagram of the perovskite solar cell device prepared in Example 1; from bottom to top, it consists of a conductive glass layer, a hole transport layer, a perovskite absorber layer, an electron transport layer, a hole blocking layer, and a metal electrode; Figure 2 It is the structural formula of hydroxyethyl cellulose, the perovskite layer doping material in Example 1; Figure 3 The UV-Vis absorption spectra of the perovskite layers in Comparative Example 2 and Example 1 are shown. Figure 4The JV curves are shown for the perovskite solar cell devices prepared in Comparative Example 1, Comparative Example 2, and Example 1. Figure 5 Here is a SEM image of the perovskite thin film prepared in Comparative Example 2; Figure 6 This is a SEM image of the perovskite thin film prepared in Example 1; Figure 7 The dark current test results are shown for the perovskite solar cells prepared in Comparative Example 2 and Example 1. Figure 8 This is a contact angle test diagram of the perovskite solution prepared in Comparative Example 2 being dropped onto the hole transport layer; Figure 9 This is a contact angle test diagram of the perovskite solution prepared in Example 1 being dropped onto the hole transport layer. Detailed Implementation Example 1

[0023] like Figure 1 As shown, the perovskite solar cell device, from bottom to top, consists of a conductive glass layer, a hole transport layer, a perovskite absorber layer, an electron transport layer, a hole blocking layer, and a metal electrode; the fabrication method is as follows: 1. Preparation of the precursor solution: Tin iodide SnI2, formamidinium iodide FAI, phenylethyl ammonium bromide PEABr, and tin fluoride SnF were dissolved in a mixed solvent of N,N-dimethylformamide DMF and dimethyl sulfoxide DMSO (DMF to DMSO volume ratio 4:1) at a molar ratio of 1:0.85:0.15:0.1. Hydroxyethyl cellulose (structural formula as shown) was then added. Figure 2 As shown in the figure, the mixed solution was stirred at room temperature for 24 hours to obtain a perovskite precursor solution with a concentration of 1 mol / L, wherein the concentration of hydroxyethyl cellulose was 0.5 mg / mL.

[0024] 2. Substrate pretreatment: The ITO glass substrate was ultrasonically cleaned with detergent, deionized water, acetone, and ethanol, respectively, for 20 minutes each. After drying, the glass substrate was placed in a 65°C oven for at least four hours to ensure that any residual liquid evaporated completely.

[0025] 3. Preparation of hole transport layer: PEDOT:PSS was spin-coated onto the treated ITO conductive glass at 4000 rpm for 40 s using a spin coater. The glass was then annealed in air at 170 °C for 20 min to form the hole transport layer.

[0026] 4. Preparation of the perovskite light-absorbing layer: 40 µL of perovskite precursor was pipetted onto the glass substrate surface, and spin coating was initiated. The spin coating parameters were set as follows: rotation speed 5000 rpm, acceleration 5000 rpm / s, and time 36 s. At the 13th second of spin coating, 150 µL of the anti-solvent chlorobenzene was pipetted and uniformly poured into the spin coating solution. After spin coating, the glass substrate was placed on a hot plate and annealed at 70 °C for 10 minutes.

[0027] 5. Preparation of the electron transport layer: 40 µL of PCBM was pipetted onto the glass substrate surface and spin-coated. The spin-coating process was as follows: spin speed 1200 rpm, acceleration 500 rpm / s, and time 30 s. After spin-coating, the glass substrate was placed on a hot plate and annealed at 70 °C for 6 min.

[0028] 6. Preparation of the hole-blocking layer: A hole-blocking layer was formed by evaporating the organic small molecule material 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) using a vacuum evaporation device. The thickness of the hole-blocking layer was 8 nm, the evaporation rate was 0.4 Å / s, and the evaporation pressure environment was less than 4 × 10⁻⁶. -4 Pa.

[0029] 7. Fabrication of the metal cathode: Metallic Ag is deposited onto the hole-blocking layer to form a metal cathode layer with a thickness of 100 nm. The deposition rate is 0.8 Å / s, and the deposition pressure environment is less than 4 × 10⁻⁶. -4 Pa.

[0030] The JV curve of the device was measured at room temperature, as follows: Figure 4 As shown in the figure, the open-circuit voltage of the device with the optimal doping ratio (0.5 mg / mL) is 0.50 V, and the short-circuit current is 17.18 mA / cm². 2 The fill factor is 0.6522 and the photoelectric conversion efficiency is 5.58%.

[0031] The key to the success of this technical solution lies in two factors: (1) using hydroxyethyl cellulose as a dopant in the tin-based perovskite precursor solution, and (2) more importantly, precisely controlling the doping concentration of hydroxyethyl cellulose. Experiments have shown that a suitable doping concentration promotes more complete crystallization of the tin-based perovskite precursor solution, reduces pinholes and other defects, and forms a denser, more uniform perovskite film. This conclusion can be seen from the scanning electron microscope images of the surface morphology of the perovskite crystalline film. Figure 5 (Undoped standard devices) and Figure 6This has been confirmed in (hydroxyethyl cellulose doped modified devices). Dense and uniform tin-based perovskite crystal films, due to their low defect rate, can significantly reduce device leakage current (e.g., Figure 7 As shown in the figure, this reduces the loss of photogenerated carriers in the device, enabling them to effectively form current and thus improving the photoelectric conversion efficiency of the device. Meanwhile, in the embodiments, it was found that the water contact angle of the tin-based perovskite film modified with hydroxyethyl cellulose significantly increased from 36.4° to 49.0° (as shown in the figure). Figure 8 and Figure 9 As shown in the figure, the increase in contact angle signifies an improvement in the hydrophobicity of the perovskite film. This improved hydrophobicity helps to prevent the penetration of moisture from the air, thus mitigating the degradation of Sn in the device film. 2+ Oxidation of the device inhibits the oxidation of Sn. 2+ Oxidation leads to performance degradation. In other words, adding precisely controlled concentrations of hydroxyethyl cellulose as an additive to the tin-based perovskite precursor solution helps obtain a denser, more uniform, and low-defect tin-based perovskite film. This effectively prevents the penetration of moisture from the air into the tin-based perovskite film and inhibits the degradation of tin-based perovskite solar cells due to Sn oxidation. 2+ Device failure is caused by oxidation.

[0032] from Figure 4 It can be seen that, using the same method as in Example 1 to prepare perovskite solar cell devices, with hydroxyethyl cellulose concentrations of 0.3 mg / mL, 0.7 mg / mL, and 1.0 mg / mL, and measuring the JV curves of the devices under the same conditions, the perovskite solar cell devices prepared with a doping concentration of 0.3~1 mg / mL of hydroxyethyl cellulose showed the best performance. Inappropriate doping concentrations not only fail to achieve the effect of optimizing device performance (e.g., ... Figure 4 As shown in Comparative Example 1, the performance of the original device will decrease instead of improving; the performance of the perovskite solar cell device made without hydroxyethyl cellulose is also poor. Comparative Example 1

[0033] Same as in Example 1, such as Figure 1 As shown, the perovskite solar cell device, from bottom to top, consists of a conductive glass layer, a hole transport layer, a perovskite absorber layer, an electron transport layer, a hole blocking layer, and a metal electrode; the fabrication method is as follows: 1. Preparation of precursor solution: Tin iodide SnI2, formamidinium iodide FAI, phenylethyl ammonium bromide PEABr, and tin fluoride SnF were dissolved in a mixed solvent of N,N-dimethylformamide DMF and dimethyl sulfoxide DMSO (the volume ratio of DMF to DMSO was 4:1) at a molar ratio of 1:0.85:0.15:0.1. Then, hydroxyethyl cellulose of the same type was added. The mixture was stirred at room temperature for 24 hours to obtain a perovskite precursor solution with a concentration of 1 mol / L, wherein the concentration of hydroxyethyl cellulose was 1.5 mg / mL.

[0034] 2. Substrate pretreatment: The ITO glass substrate was ultrasonically cleaned with detergent, deionized water, acetone, and ethanol, respectively, for 20 minutes each. After drying, the glass substrate was placed in a 65°C oven for at least four hours to ensure that any residual liquid evaporated completely.

[0035] 3. Preparation of hole transport layer: PEDOT:PSS was spin-coated onto the treated ITO conductive glass at 4000 rpm for 40 s using a spin coater. The glass was then annealed in air at 170°C for 20 min to form the hole transport layer.

[0036] 4. Preparation of the perovskite light-absorbing layer: 40 µL of perovskite precursor was pipetted onto the glass substrate surface, and spin coating was initiated. The spin coating parameters were set as follows: rotation speed 5000 rpm, acceleration 5000 rpm / s, and time 36 s. At the 13th second of spin coating, 150 µL of the anti-solvent chlorobenzene was pipetted and uniformly poured into the spin coating solution. After spin coating, the glass substrate was placed on a hot plate and annealed at 70 °C for 10 minutes.

[0037] 5. Preparation of the electron transport layer: 40 µL of PCBM was pipetted onto the glass substrate surface and spin-coated. The spin-coating process was as follows: spin speed 1200 rpm, acceleration 500 rpm / s, and time 30 s. After spin-coating, the glass substrate was placed on a hot plate and annealed at 70 °C for 6 min.

[0038] 6. Preparation of the hole-blocking layer: A hole-blocking layer was formed by evaporating the organic small molecule material 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) using a vacuum evaporation device. The thickness of the hole-blocking layer was 8 nm, the evaporation rate was 0.4 Å / s, and the evaporation pressure environment was less than 4 × 10⁻⁶. -4 Pa.

[0039] 7. Fabrication of the metal cathode: Metallic Ag is deposited onto the hole-blocking layer to form a metal cathode layer with a thickness of 100 nm. The deposition rate is 0.8 Å / s, and the deposition pressure environment is less than 4 × 10⁻⁶. -4 Pa.

[0040] The JV curve of the device was measured at room temperature, as follows: Figure 4 As shown, comparing the device JV of standard tin-based perovskite solar cells with other concentrations reveals that not all proportions of hydroxyethyl cellulose doping improve the device performance of tin-based perovskite solar cells. In fact, when the doping concentration exceeds 0.5 mg / mL, the device performance parameters begin to gradually decrease. When the concentration of hydroxyethyl cellulose is 1.5 mg / mL, the performance parameters of the prepared tin-based perovskite solar cell drop to: open-circuit voltage of 0.47 V and short-circuit current of 14.39 mA / cm². 2 The fill factor was 0.5893, and the photoelectric conversion efficiency was 4.05%. At this point, the device's performance parameters were not only far lower than those of a tin-based perovskite solar cell with a doping concentration of 0.5 mg / mL, but even lower than those of an undoped standard. This demonstrates that precisely controlling the doping concentration of hydroxyethyl cellulose is crucial for the successful implementation of this technical solution. Comparative Example 2

[0041] 1. Preparation of precursor solution: Tin iodide SnI2, formamidinium iodide FAI, phenylethyl ammonium bromide PEABr, and tin fluoride SnF were dissolved in a mixed solvent of N,N-dimethylformamide DMF and dimethyl sulfoxide DMSO (the volume ratio of DMF to DMSO was 4:1) at a molar ratio of 1:0.85:0.15:0.1. The mixed solution was stirred at room temperature for 24 hours to obtain a perovskite precursor solution with a concentration of 1 mol / L, which was then ready for use.

[0042] 2. Substrate pretreatment: The ITO glass substrate was ultrasonically cleaned with detergent, deionized water, acetone, and ethanol, respectively, for 20 minutes each. After drying, the glass substrate was placed in a 65°C oven for at least four hours to ensure that any residual liquid evaporated completely.

[0043] 3. Preparation of hole transport layer: PEDOT:PSS was spin-coated onto the treated ITO conductive glass at a speed of 4000 rpm for 40 s. The glass was then annealed in air at 170°C for 20 min to form a hole transport layer.

[0044] 4. Preparation of the perovskite light-absorbing layer: 40 µL of perovskite precursor was pipetted onto the glass substrate surface, and spin coating was initiated. The spin coating parameters were set as follows: rotation speed 5000 rpm, acceleration 5000 rpm / s, and time 36 s. At the 13th second of spin coating, 150 µL of the anti-solvent chlorobenzene was pipetted and uniformly poured into the spin coating solution. After spin coating, the glass substrate was placed on a hot plate and annealed at 70 °C for 10 minutes.

[0045] 5. Preparation of the electron transport layer: 40 µL of PCBM was pipetted onto the glass substrate surface and spin-coated. The spin-coating process was as follows: rotation speed 1200 rpm, acceleration 500 rpm / s, and time 30 s. After spin-coating, the glass substrate was placed on a hot plate and annealed at 70 °C for 6 min.

[0046] 6. Preparation of the hole-blocking layer: A hole-blocking layer was formed by vacuum evaporation of the organic small molecule material 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP). The thickness of the hole-blocking layer was 8 nm, the evaporation rate was 0.4 Å / s, and the evaporation pressure environment was less than 4 × 10⁻⁶. -4 Pa.

[0047] 7. Fabrication of the metal cathode: Metallic Ag is deposited onto the hole-blocking layer to form a metal cathode layer with a thickness of 100 nm. The deposition rate is 0.8 A / s, and the deposition pressure environment is less than 4 × 10⁻⁶. -4 Pa.

[0048] The JV curve of the device was measured at room temperature, as follows: Figure 4 As shown in the figure, the open-circuit voltage of the device is 0.46V, and the short-circuit current is 14.62 mA / cm². 2 The fill factor is 0.6176 and the efficiency is 4.22%.

[0049] It should be noted that the above embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Equivalent substitutions or alternatives made on the basis of the above shall all fall within the scope of protection of the present invention.

Claims

1. A method of hydroxyethylcellulose doping to optimize the performance of two-dimensional / three-dimensional tin-based perovskite solar cells, characterized by, The method comprises the following steps: S1, adding hydroxyethyl cellulose into a perovskite precursor solution to form a mixed solution; the perovskite precursor solution comprises tin iodide SnI2, formamidinium iodide FAI, phenethylammonium bromide PEABr and tin fluoride; the concentration of hydroxyethyl cellulose in the mixed solution is 0.3-1.0 mg / mL; S2, depositing the mixed solution prepared in step S1 on a substrate and performing annealing treatment to form a two-dimensional / three-dimensional tin-based perovskite film doped with hydroxyethyl cellulose.

2. The method of claim 1, wherein, The specific method of step S1 is as follows: dissolving tin iodide SnI2, formamidinium iodide FAI, phenethylammonium bromide PEABr and tin fluoride in an organic solvent, then adding a hydroxyethyl cellulose solution, and mixing and stirring to prepare the mixed solution; the molar ratio of tin iodide SnI2, formamidinium iodide FAI, phenethylammonium bromide PEABr and tin fluoride SnF is 1:0.85:0.15:0.1, and the total concentration of the mixed solution is 1.0 mol / L.

3. The method of claim 2, wherein, The organic solvent is a mixed solvent of N,N-dimethylformamide DMF and dimethyl sulfoxide DMSO, and the volume ratio of DMF to DMSO is 4:

1.

4. The method of claim 1, wherein, In step S2, the mixed solution prepared in step S1 is deposited on a conductive glass substrate coated with a hole transport layer by spin coating.

5. The method of claim 4, wherein, The parameters of spin coating are 5000 rpm for 36 seconds.

6. The method of claim 1, wherein, In step S2, the annealing process is performed at 70°C for 10 minutes.

7. A perovskite solar cell, characterized by, The structure comprises a conductive glass layer, a hole transport layer, a perovskite absorption layer, an electron transport layer, a hole blocking layer and a metal electrode which are sequentially stacked; wherein the perovskite absorption layer is prepared by the method according to any one of claims 1-6.

8. The perovskite solar cell of claim 7, wherein the perovskite layer is formed by a two-step method. The chemical composition of the perovskite absorption layer is hydroxyethyl cellulose-doped PEA 0.15 FA 0.85 SnI 2.85 Br 0.15 .

9. The perovskite solar cell according to claim 7 or 8, characterized in that, The hole transport layer material is PEDOT:PSS; The electron transport layer material is PCBM; The hole blocking layer material is BCP; The metal electrode is a silver electrode; The conductive glass layer is ITO conductive glass.

10. A method of producing a perovskite solar cell, characterized by, The method comprises the following steps: D1, spin coating a hole transport layer on ITO conductive glass; D2, preparing a perovskite absorption layer on the hole transport layer: spin coating the mixed solution prepared by the method according to any one of claims 1-6 on the surface of the hole transport layer, adding 150 μL chlorobenzene as an anti-solvent at the 13th second during spin coating, and performing annealing treatment after spin coating is completed; D3, spin coating an electron transport layer on the perovskite absorption layer, spin coating for 30 seconds, and then performing annealing; D4, preparing a hole blocking layer on the electron transport layer by an evaporation process; D5, evaporating a silver electrode on the hole blocking layer to complete the preparation of the cell.

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