A vanadium-doped nitrogen-fluorine-doped vertical graphene material and perovskite solar cell

Abstract

The present invention discloses a vanadium-doped nitrogen-fluorine-doped vertical graphene material and a perovskite solar cell, relating to the technical field of perovskite solar cells. The technical solution is as follows: adding graphite oxide to deionized water for ultrasonic treatment, adding ammonia and ethylene glycol for hydrothermal reaction, and freeze-drying to obtain a three-dimensional graphite foam; immersing the three-dimensional graphite foam in a vanadium ion solution to adsorb vanadium; drying and heat-treating with argon to obtain a V-3D-GO material; heating and introducing methane in a CVD system to obtain VG@V-3D-GF for vertical graphene growth; and performing a nitrogen-fluorine plasma reaction to obtain a vanadium-doped nitrogen-fluorine-doped vertical graphene material. The present invention uses three-dimensional graphene foam instead of sponge nickel to achieve ternary co-doping through vanadium-doped nitrogen-fluorine doping, thereby improving conductivity and stability. The CVD process is used to simplify the preparation process and improve production efficiency and consistency. The material improves photoelectric conversion efficiency and stability in perovskite solar cells.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite solar cells, and in particular to a vanadium-doped nitrogen-fluorine-doped vertical graphene material and a perovskite solar cell thereof. Background Art

[0002] With the rapid development of flexible electronics in recent years, graphene-based materials have attracted significant attention due to their excellent conductivity, lightweight, and flexible properties. Graphene not only excels in electronic devices but also demonstrates promising potential in new energy applications, such as perovskite solar cells. However, existing graphene materials still face numerous challenges in practical application, particularly in the selection of substrate materials, optimization of electronic structures, and simplification of fabrication processes. Through continuous technological innovation, researchers strive to overcome these bottlenecks and promote the wider application of graphene materials.

[0003] In the prior art, CN115893389B document proposes a preparation method of sponge nickel loaded nitrogen and fluorine doped vertical graphene. Although the method improves the electrical conductivity of the material to a certain extent, sponge nickel, as a base material, is still faced with the problem of large weight and insufficient flexibility, which limits its application in flexible electronic devices. In addition, the traditional nitrogen and fluorine doping strategies have limited effects in improving the electrical conductivity of graphene and optimizing the electronic structure, and often cannot form an effective synergistic doping effect. Meanwhile, although the existing PECVD (plasma enhanced chemical vapor deposition) preparation method can achieve the doping of graphene, it is difficult to achieve large-scale commercial production due to its complex process and high energy consumption and strict requirements on equipment. These problems not only affect the performance of the material, but also restrict the application of graphene in higher performance electronic devices, especially in the occasions where light weight, flexibility and high conductivity are needed.

[0004] To address these challenges, the development of new materials and preparation technologies is urgently needed to enhance the lightweight and flexibility of the substrate materials, while also improving the conductivity and electronic structure of graphene materials. Furthermore, simplifying the preparation process and enhancing its controllability and consistency are key to improving material performance. These technical challenges not only affect the inherent properties of graphene materials but also directly impact their application in high-performance electronic devices such as perovskite solar cells. The necessity and urgency of achieving these goals are becoming increasingly prominent, and promoting continuous innovation and development in related fields has become a critical task.

[0005] The present invention aims to address the aforementioned technical challenges by enhancing the overall performance of graphene-based materials through innovative doping strategies and improved material preparation methods. In particular, the introduction of vanadium for ternary co-doping is expected to create a more effective synergistic effect, significantly improving the conductivity and stability of the material. Furthermore, by optimizing the preparation process to reduce energy consumption and costs, the invention will further promote the widespread application of graphene materials in flexible electronic devices and new energy fields. Achieving these goals will provide new impetus and possibilities for the development of future electronic devices. Summary of the Invention

[0006] In order to achieve the above-mentioned purpose of the invention and address the above-mentioned technical problems, the present invention provides a method for preparing a vanadium-doped nitrogen-fluorine-doped vertical graphene material, which mainly comprises the following steps:

[0007] A1: Graphite oxide is added to deionized water and ultrasonically treated for 2-3 hours to obtain a uniform graphite oxide dispersion. The graphite oxide dispersion is then transferred to a polytetrafluoroethylene liner, ammonia and ethylene glycol are added, and the mixture is sealed and subjected to a hydrothermal reaction in a reactor for 12-20 hours. After the reaction, the mixture is naturally cooled to room temperature to form a graphite gel, which is then washed three times with deionized water and freeze-dried in a freeze dryer to obtain a three-dimensional graphite foam (3D-GO).

[0008] A2: Prepare a vanadium ion solution with deionized water and vanadium nitrate pentahydrate, completely immerse the three-dimensional graphite foam in the vanadium ion solution, and let it stand to allow the vanadium ions to be fully adsorbed on the graphite foam;

[0009] After the A3 impregnation was completed, the sample was taken out, washed with deionized water to remove the residual solution on the surface, dried at 80 ° C for 6 hours, placed in a tube furnace, and passed through argon gas for heat treatment to fix the vanadium element and reduce some vanadium ions to form V-3D-G0 material;

[0010] A4 placed the V-3D-G0 material in a chemical vapor deposition (CVD) system, evacuated to 10 Pa, introduced argon (100 sccm) and hydrogen (20 sccm), maintained the pressure at 100 Pa and slowly increased the temperature, then introduced methane for reaction. After the reaction, the argon and hydrogen flow rates were maintained and the temperature was lowered to room temperature to obtain a VG@V-3D-GF material with vertical graphene growth.

[0011] A5 placed the VG@V-3D-GF material in the reaction chamber of a plasma-enhanced chemical vapor deposition (PECVD) system; evacuated to 10 Pa, introduced nitrogen (50 sccm) and sulfur hexafluoride (10 sccm) to carry out a plasma reaction. After the reaction, nitrogen (100 sccm) was introduced and the material was naturally cooled to room temperature to obtain vanadium-doped nitrogen-fluorine-doped vertical graphene material (NFV-VG@V-3D-GF).

[0012] Preferably, in step A1, the concentration of the graphite oxide dispersion is 0.005-0.02 g / mL, the volume ratio of the graphite oxide dispersion, ammonia water and ethylene glycol is 20:1:1-20:2:2, and the temperature of the hydrothermal reactor is 120-180°C.

[0013] Preferably, in step A2, the concentration of the vanadium ion solution is 0.5-0.15 mol / L, and the standing time is 8-16 hours.

[0014] Preferably, in step A3, the heat treatment temperature is 500-650°C.

[0015] Preferably, in step A4, the temperature is raised to 700-850° C., the heating rate is 5-15° C. / min, the carbon source is methane, and the flow rate is 10-30 sccm.

[0016] Preferably, in step A5, the radio frequency power of plasma doping is 60-100 W, the doping time is 15-30 minutes, and the reaction temperature is 80-100° C.

[0017] The present invention also provides a vanadium-doped nitrogen-fluorine-doped vertical graphene material, which is prepared by the above-mentioned preparation method.

[0018] The present invention also provides a method for preparing a perovskite solar cell, comprising the following steps:

[0019] B1: Cut the FTO conductive glass into 2 cm × 2 cm size, ultrasonicate it in acetone, anhydrous ethanol and deionized water for 15 minutes each, and treat it in a UV-ozone cleaner for 15 minutes;

[0020] B2: Tetrabutyl titanate was dissolved in an ethanol solution containing 1% hydrochloric acid to a mass percentage of 3-7%, and spin-coated (2000 rpm for 30 seconds) to obtain a dense TiO2 layer, which was then dried at 150°C for 10 minutes. TiO2 nanoparticles were dispersed in ethanol to a concentration of 10-30 mg / mL, and spin-coated (3000 rpm for 30 seconds), and sintered at 500°C for 30 minutes.

[0021] B3: PbI2 and CH3NH3I at a molar ratio of 1:1 were dissolved in a mixed solvent of DMF (N,N-dimethylformamide) and GBL (γ-butyrolactone) at a volume ratio of 4:1 to a concentration of 500-700 mg / ml. The mixture was stirred at 70°C until the solution became clear. The solution was then spin-coated (1000 rpm for 10 seconds, followed by 4000 rpm for 30 seconds). Chloroform was added dropwise 15 seconds into the spin coating process. The solution was then heated at 100°C for 10 minutes.

[0022] B4: Disperse the vanadium-doped nitrogen-fluorine-doped vertical graphene material in isopropanol by ultrasonication for 30 minutes to form a dispersion with a concentration of 0.5-1.5 mg / mL; spin-coat the dispersion at 2000-3500 rpm for 30 seconds and dry at 80°C for 5 minutes;

[0023] B5: Spiro-OMeTAD was dissolved in chloroform to form a solution with a concentration of 60-80 mg / mL. 4% of the solution volume was added with a 4-tert-butylpyridine solution and a lithium bis(trifluoromethanesulfonyl)imide solution, wherein the volume ratio of 4-tert-butylpyridine to lithium bis(trifluoromethanesulfonyl)imide was 1.5:1. The solution was then spin-coated (4000 rpm for 30 seconds) and allowed to stand at room temperature for 12 hours.

[0024] B6 in 2×10 -4 In a vacuum evaporation device at Pa, a gold electrode with a thickness of 80nm was deposited.

[0025] Preferably, the vanadium-doped nitrogen-fluorine-doped vertical graphene material is prepared by the above-mentioned preparation method.

[0026] The present invention also provides a perovskite solar cell, which is prepared by the above preparation method.

[0027] The technical solution provided by the present invention brings beneficial effects:

[0028] This invention uses three-dimensional graphene foam (3D-GO) instead of traditional nickel sponge as the substrate material, significantly reducing the overall weight of the material while improving its flexibility. This material not only possesses excellent electrical conductivity and structural support properties, but also, due to its lightweight properties, is more suitable for flexible electronic devices. This improves the material's mechanical adaptability and environmental stability, enabling flexible electronic devices to achieve longer lifespans and better performance in dynamic and complex environments.

[0029] By introducing vanadium in addition to nitrogen and fluorine doping, ternary co-doping was achieved. This synergistic doping strategy effectively improved the electronic structure of the material and significantly enhanced its conductivity. Experimental results showed that ternary doping not only increased the carrier concentration but also optimized the band structure, thereby improving the material's stability and conductivity in electrochemical applications. This technological innovation provides stronger support for the design of high-performance electronic devices.

[0030] The present invention uses chemical vapor deposition (CVD) instead of the traditional PECVD process, simplifying the preparation process. This improvement reduces production energy consumption and equipment requirements, improving process controllability and material consistency. Furthermore, the simplified process significantly improves material production efficiency, thereby facilitating the large-scale application of graphene materials.

[0031] The application of vanadium-doped, nitrogen-doped, and fluorine-doped vertical graphene materials in the interface layer of perovskite solar cells has significantly improved the device's photoelectric conversion efficiency and stability. Through improved interface engineering, this new material can effectively optimize the transport of electrons and holes, improving the overall performance of the device and giving it broader application prospects in new high-performance fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a photo of the three-dimensional graphite foam of Example 1 of the present invention;

[0033] Figure 2 This is an SEM photograph of the three-dimensional graphite foam of Example 1 of the present invention;

[0034] Figure 3 This is an SEM photograph of vanadium-doped nitrogen-fluorine-doped vertical graphene according to Example 1 of the present invention. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the embodiments. Of course, the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0036] Example 1

[0037] In order to achieve the above-mentioned purpose of the invention and address the above-mentioned technical problems, the present invention provides a method for preparing a vanadium-doped nitrogen-fluorine-doped vertical graphene material, which mainly comprises the following steps:

[0038] A1: Graphite oxide was added to deionized water and ultrasonically treated for 3 hours to obtain a uniform graphite oxide dispersion with a concentration of 0.01 g / mL. The graphite oxide dispersion was then transferred to a polytetrafluoroethylene liner and added with ammonia water and ethylene glycol at a volume ratio of 20:1:1. The liner was sealed and reacted in a hydrothermal reactor at 180°C for 20 hours. After the reaction, the liner was naturally cooled to room temperature to form a graphite gel. The liner was washed with deionized water three times and freeze-dried in a freeze dryer to obtain a three-dimensional graphite foam (3D-GO).

[0039] A2: Prepare a 0.1 mol / L vanadium ion solution using deionized water and vanadium nitrate pentahydrate. Completely immerse the three-dimensional graphite foam in the vanadium ion solution and allow it to stand for 16 hours to allow the vanadium ions to fully adsorb onto the graphite foam.

[0040] After the A3 impregnation was completed, the sample was taken out, washed with deionized water to remove the residual solution on the surface, dried at 80°C for 6 hours, placed in a tube furnace, introduced argon gas with a flow rate of 100 sccm, and heat treated at 650°C for 2 hours to fix the vanadium element and reduce some vanadium ions to form V-3D-G0 material;

[0041] A4 placed the V-3D-G0 material in a chemical vapor deposition (CVD) system, evacuated to 10 Pa, introduced argon (100 sccm) and hydrogen (20 sccm), maintained the pressure at 100 Pa, and slowly heated to 850°C at a heating rate of 10°C / min. Methane was introduced for reaction at a flow rate of 30 sccm and maintained for 30 minutes. After the reaction was completed, the flow rates of argon and hydrogen were maintained and the temperature was lowered to room temperature to obtain a VG@V-3D-GF material with vertical graphene growth.

[0042] A5 placed the VG@V-3D-GF material in the reaction chamber of a plasma-enhanced chemical vapor deposition (PECVD) system; evacuated to 10 Pa, introduced nitrogen (50 sccm) and sulfur hexafluoride (10 sccm) to carry out a plasma reaction, the RF power of the plasma doping was 100 W, the doping time was 30 minutes, and the reaction temperature was 100°C. After the reaction was completed, nitrogen (100 sccm) was introduced and naturally cooled to room temperature to obtain vanadium-doped nitrogen-fluorine-doped vertical graphene material (NFV-VG@V-3D-GF).

[0043] A method for preparing a perovskite solar cell comprises the following steps:

[0044] B1: Cut the FTO conductive glass into 2 cm × 2 cm size, ultrasonicate it in acetone, anhydrous ethanol and deionized water for 15 minutes each, and treat it in a UV-ozone cleaner for 15 minutes;

[0045] B2: Tetrabutyl titanate was dissolved in an ethanol solution containing 1% hydrochloric acid to a mass percentage of 5%, and the solution was spin-coated (2000 rpm for 30 seconds) to obtain a dense TiO2 layer, which was then dried at 150°C for 10 minutes. TiO2 nanoparticles were dispersed in ethanol to a concentration of 10-30 mg / mL, and spin-coated (3000 rpm for 30 seconds). The resulting solution was sintered at 500°C for 30 minutes.

[0046] B3: PbI2 and CH3NH3I in a 1:1 molar ratio were dissolved in a 4:1 volume ratio of DMF (N,N-dimethylformamide) and GBL (γ-butyrolactone) solvent mixture to a concentration of 620 mg / ml. The mixture was stirred at 70°C until the solution became clear. The mixture was then spin-coated (1000 rpm for 10 seconds, followed by 4000 rpm for 30 seconds). Chloroform was added dropwise 15 seconds into the spin-coating process. The mixture was heated at 100°C for 10 minutes after the spin-coating process.

[0047] B4: Ultrasonic dispersion of the vanadium-doped, nitrogen-doped, and fluorine-doped vertical graphene material according to claim 7 in isopropanol for 30 minutes to form a dispersion with a concentration of 1 mg / mL; spin coating the dispersion at 3000 rpm for 30 seconds, and drying at 80° C. for 5 minutes;

[0048] B5: Spiro-OMeTAD was dissolved in chloroform to form a 72 mg / mL solution, and a 4% volume of 4-tert-butylpyridine solution and a lithium bis(trifluoromethanesulfonyl)imide solution were added, wherein the volume ratio of 4-tert-butylpyridine to lithium bis(trifluoromethanesulfonyl)imide was 1.5:1. The solution was then spin-coated (4000 rpm for 30 seconds) and allowed to stand at room temperature for 12 hours.

[0049] B6 in 2×10 -4 In a vacuum evaporation device at Pa, a gold electrode with a thickness of 80nm was deposited.

[0050] Example 2

[0051] The preparation was carried out in the same manner as in Example 1, except that the concentration of the graphite oxide dispersion in step A1 was 0.005 g / mL.

[0052] Example 3

[0053] The preparation was carried out in the same manner as in Example 1, except that the concentration of the graphite oxide dispersion in step A1 was 0.02 g / mL.

[0054] Example 4

[0055] The preparation was carried out according to the same preparation method as in Example 1, except that the hydrothermal reaction temperature in step A1 was 120°C.

[0056] Example 5

[0057] The preparation was carried out according to the same preparation method as in Example 1, except that the concentration of the vanadium ion solution in step A2 was 0.5 mol / L.

[0058] Example 6

[0059] The preparation was carried out according to the same preparation method as in Example 1, except that the concentration of the vanadium ion solution in step A2 was 0.15 mol / L.

[0060] Example 7

[0061] The preparation was carried out in the same manner as in Example 1, except that the standing time in step A2 was 8 hours.

[0062] Example 8

[0063] The preparation method is the same as that of Example 1, except that the heat treatment temperature in step A3 is 650°C.

[0064] Example 9

[0065] The preparation was carried out in the same manner as in Example 1, except that in step A4, the temperature was raised to 700° C. and the methane flow rate was 10 sccm.

[0066] Example 10

[0067] The preparation was carried out in the same manner as in Example 1, except that the radio frequency power of plasma doping in step A5 was 60 W and the reaction temperature was 80°C.

[0068] Example 11

[0069] The same preparation method as in Example 1 was used for preparation, except that the concentration of the dispersion in step B4 was 0.5 mg / mL.

[0070] Example 12

[0071] The same preparation method as in Example 1 was used for preparation, except that the concentration of the dispersion in step B4 was 1.5 mg / mL.

[0072] Comparative Example 1

[0073] The same preparation method as in Example 1 was used for the preparation, except that the three-dimensional graphite foam (3D-GO) was replaced by the substrate material sponge nickel.

[0074] A2: Prepare a 0.1 mol / L vanadium ion solution with deionized water and vanadium nitrate pentahydrate, completely immerse the nickel sponge in the vanadium ion solution, and let it stand for 16 hours to allow the vanadium ions to be fully adsorbed onto the nickel sponge;

[0075] After the A3 impregnation was completed, the sample was taken out, washed with deionized water to remove the residual solution on the surface, dried at 80°C for 6 hours, placed in a tube furnace, introduced argon gas with a flow rate of 100 sccm, and heat treated at 650°C for 2 hours to fix the vanadium element and reduce some vanadium ions to form V-sponge nickel material;

[0076] A4 placed the V-sponge nickel material in a chemical vapor deposition (CVD) system, evacuated to 10 Pa, introduced argon (100 sccm) and hydrogen (20 sccm), maintained the pressure at 100 Pa, and slowly heated to 850°C at a heating rate of 10°C / min. Methane was introduced at a flow rate of 30 sccm and the reaction was maintained for 30 minutes. After the reaction was completed, the flow rates of argon and hydrogen were maintained and the temperature was lowered to room temperature to obtain a sponge nickel material with vertical graphene growth.

[0077] A5 placed the VG@V-3D-GF material in the reaction chamber of a plasma-enhanced chemical vapor deposition (PECVD) system; evacuated to 10 Pa, introduced nitrogen (50 sccm) and sulfur hexafluoride (10 sccm) to carry out a plasma reaction. The RF power of the plasma doping was 100 W, the doping time was 30 minutes, and the reaction temperature was 100°C. After the reaction was completed, nitrogen (100 sccm) was introduced and naturally cooled to room temperature to obtain sponge nickel vanadium doped nitrogen fluorine doped vertical graphene material.

[0078] Comparative Example 2

[0079] The same preparation method as in Example 1 was used for the preparation, except that only nitrogen and fluorine doping was performed.

[0080] Graphite oxide was added to deionized water and ultrasonically treated for 3 hours to obtain a uniform graphite oxide dispersion with a concentration of 0.01 g / mL. The graphite oxide dispersion was then transferred to a polytetrafluoroethylene liner and added with ammonia water and ethylene glycol. The volume ratio of the graphite oxide dispersion, ammonia water, and ethylene glycol was 20:1:1. After sealing, the mixture was reacted in a hydrothermal reactor at 180°C for 20 hours. After the reaction, the mixture was naturally cooled to room temperature to form a graphite gel, which was washed three times with deionized water and freeze-dried in a freeze dryer to obtain three-dimensional graphite foam (3D-GO).

[0081] The three-dimensional graphite foam (3D-GO) was placed in a chemical vapor deposition (CVD) system, evacuated to 10Pa, and argon (100sccm) and hydrogen (20sccm) were introduced. The pressure was maintained at 100Pa and the temperature was slowly increased to 850℃ at a heating rate of 10℃ / min. Methane was introduced at a flow rate of 30sccm and the reaction was maintained for 30 minutes. After the reaction was completed, the flow rates of argon and hydrogen were maintained and the temperature was cooled to room temperature to obtain VG@V-3D-GF material with vertical graphene growth.

[0082] A5 placed the VG@V-3D-GF material in the reaction chamber of a plasma-enhanced chemical vapor deposition (PECVD) system; evacuated to 10 Pa, introduced nitrogen (50 sccm) and sulfur hexafluoride (10 sccm) to carry out a plasma reaction, the RF power of the plasma doping was 100 W, the doping time was 30 minutes, and the reaction temperature was 100°C. After the reaction was completed, nitrogen (100 sccm) was introduced and naturally cooled to room temperature to obtain vanadium-doped nitrogen-fluorine-doped vertical graphene material (NFV-VG@V-3D-GF).

[0083] Experimental test:

[0084] 1. Photovoltaic conversion efficiency (PCE) test

[0085] Test method equipment: IV test system, condition: 100mW / cm2 , AM 1.5G light, 25℃ ambient temperature.

[0086] step:

[0087] The IV curve of the cell was measured using a solar simulator. The open circuit voltage (Voc), short circuit current (Jsc), fill factor (FF), and PCE were extracted from the IV curve.

[0088] 2. Cyclic stability test

[0089] Test Method

[0090] Equipment: electrochemical workstation, conditions: constant current charge and discharge, 0.5C or 1C.

[0091] step:

[0092] Perform charge and discharge cycles and record the charge and discharge capacity of the battery.

[0093] The capacity decay of the battery after 500 cycles was tested and the coulombic efficiency was calculated.

[0094] 3.Electron transport performance test (EIS)

[0095] Equipment: Electrochemical workstation.

[0096] Test conditions: open circuit voltage, frequency range is 1Hz to 1MHz.

[0097] Steps: Perform EIS test on the battery.

[0098] Table 1 Experimental data summary

[0099]

[0100] The examples of the present invention showed significant improvements in photoelectric conversion efficiency (PCE) compared to the control group, demonstrating that vanadium-doped, nitrogen-doped, and fluorine-doped vertical graphene materials can effectively improve the photoelectric conversion efficiency of perovskite solar cells. Even under different process and doping conditions, the examples maintained high efficiency, demonstrating the optimization of photoelectric performance brought about by material modification.

[0101] Capacity fade: The examples of the present invention have significant advantages in terms of capacity fade, especially in longer-term testing, demonstrating excellent stability. Compared to the control group, the capacity fade of the materials of the present invention is lower, indicating that their stability and durability in long-term use have been effectively improved.

[0102] The examples of the present invention exhibited significantly higher coulombic efficiencies than the comparative examples, indicating that the present materials can more efficiently recover charge and reduce energy loss. In all examples, the coulombic efficiencies were superior to those of the comparative examples, further demonstrating the importance of the synergistic effects of vanadium doping and nitrogen and fluorine doping in improving battery efficiency.

[0103] The charge transfer impedance in the examples is low, demonstrating advantages in the charge transfer process. Lower charge transfer impedance indicates that the material has better conductivity and charge transfer capabilities, contributing to improved overall battery performance. Compared to the control group, the examples show significant improvement in charge transfer impedance, validating the contribution of the present invention to improving battery performance.

[0104] The examples of the present invention demonstrated excellent performance across multiple key performance indicators (photovoltaic conversion efficiency, capacity decay, coulombic efficiency, and charge transfer impedance), demonstrating the strong advantages of vanadium-doped, nitrogen-fluorine-doped vertical graphene materials for use in perovskite solar cells. Compared to the control group, the examples demonstrated significant improvements in battery performance, extended battery life, and optimized charge transfer.

[0105] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing vanadium-doped nitrogen-fluorine-doped vertical graphene material, characterized in that: The method comprises the following steps: A1: Graphite oxide is added to deionized water and ultrasonically treated to obtain a uniform graphite oxide dispersion. Ammonia and ethylene glycol are then added to carry out a hydrothermal reaction. After the reaction, the mixture is naturally cooled to form a graphite gel, which is then washed with deionized water and freeze-dried to obtain a three-dimensional graphite foam. A2: Prepare a vanadium ion solution with deionized water and vanadium nitrate pentahydrate, completely immerse the three-dimensional graphite foam in the vanadium ion solution, and let it stand to allow the vanadium ions to be fully adsorbed on the graphite foam; After the impregnation of A3 is completed, it is dried, placed in a tube furnace, introduced with argon gas, and heat treated to form V-3D-G0 material; A4 placed the V-3D-G0 material in a chemical vapor deposition system, evacuated it, introduced argon and hydrogen, maintained the pressure and slowly raised the temperature, then introduced methane for reaction. After the reaction was completed, the flow rates of argon and hydrogen were maintained and the temperature was lowered to room temperature to obtain a VG@V-3D-GF material with vertical graphene growth. A5 placed the VG@V-3D-GF material in the reaction chamber of the plasma enhanced chemical vapor deposition system; The process is vacuumed, and nitrogen and sulfur hexafluoride are introduced to carry out a plasma reaction. After the reaction is completed, nitrogen is introduced and the mixture is naturally cooled to room temperature to obtain a vanadium-doped nitrogen-fluorine-doped vertical graphene material.

2. The method for preparing the vanadium-doped nitrogen-fluorine-doped vertical graphene material according to claim 1, characterized in that: In step A1, the concentration of the graphite oxide dispersion is 0.005-0.02 g / mL, the volume ratio of the graphite oxide dispersion, ammonia water and ethylene glycol is 20:1:1-20:2:2, and the temperature of the hydrothermal reactor is 120-180°C.

3. The method for preparing vanadium-doped nitrogen-fluorine-doped vertical graphene material according to claim 1, characterized in that: In step A2, the concentration of the vanadium ion solution is 0.5-0.15 mol / L, and the standing time is 8-16 hours.

4. The method for preparing vanadium-doped nitrogen-fluorine-doped vertical graphene material according to claim 1, characterized in that: In step A3, the heat treatment temperature is 500-650°C.

5. The method for preparing vanadium-doped nitrogen-fluorine-doped vertical graphene material according to claim 1, characterized in that: In step A4, the temperature is raised to 700-850°C at a heating rate of 5-15°C / min, the carbon source is methane, and the flow rate is 10-30 sccm.

6. The method for preparing vanadium-doped nitrogen-fluorine-doped vertical graphene material according to claim 1, characterized in that: In step A5, the radio frequency power of plasma doping is 60-100 W, the doping time is 15-30 minutes, and the reaction temperature is 80-100° C.

7. A vanadium-doped nitrogen-fluorine-doped vertical graphene material, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 6.

8. A method for preparing a perovskite solar cell, characterized in that: The following steps are involved: B1: ultrasonically treat the FTO conductive glass in acetone, anhydrous ethanol and deionized water in sequence, and then use a UV-ozone cleaner; B2: Tetrabutyl titanate is dissolved in an ethanol solution containing 1% hydrochloric acid at a mass percentage of 3-7%, and spin-coated to obtain a dense TiO2 layer, which is then dried. TiO2 nanoparticles are dispersed in ethanol at a concentration of 10-30 mg / mL, and spin-coated and sintered. B3: Dissolve PbI2 and CH3NH3I at a molar ratio of 1:1 in a mixed solvent of N,N-dimethylformamide and γ-butyrolactone at a volume ratio of 4:1 to a concentration of 500-700 mg / ml. Stir until the solution is clear. Then, spin-coat the solution. Add chloroform dropwise 15 seconds into the spin-coating process. Heat the solution after the spin-coating process. B4: Ultrasonic dispersion of vanadium-doped nitrogen-fluorine-doped vertical graphene material in isopropanol to form a dispersion with a concentration of 0.5-1.5 mg / mL; spin coating the dispersion at 2000-3500 rpm for 30 seconds and drying at 80°C for 5 minutes; B5: Dissolve Spiro-OMeTAD in chloroform to form a solution with a concentration of 60-80 mg / mL, add 4-tert-butylpyridine solution and lithium bis(trifluoromethanesulfonyl)imide solution accounting for 4% of the solution volume, where the volume ratio of 4-tert-butylpyridine to lithium bis(trifluoromethanesulfonyl)imide is 1.5:1, then spin-coat and let stand at room temperature; B6 is used to deposit gold electrodes in vacuum evaporation equipment. The vanadium-doped nitrogen-fluorine-doped vertical graphene material is the vanadium-doped nitrogen-fluorine-doped vertical graphene material described in claim 7.

9. A perovskite solar cell, characterized in that: The solar cell is manufactured by the manufacturing method according to claim 8.

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