A carbon-based all-inorganic csPbBr3 perovskite solar cell and a preparation method thereof

Abstract

The application discloses a carbon-based all-inorganic CsPbBr3 perovskite solar cell and a preparation method thereof, and belongs to the technical field of perovskite solar cells.The application uses SnCl2*2H2O, thiourea and PbBr2 as raw materials, and completes preparation of a SnO2 quantum dot solution in an oxygen or air atmosphere.Oxygen promotes the hydrolysis, dehydration and oxidation process of SnCl2, accelerates the synthesis process of SnO2, shortens the reaction time, and reduces the generation of oxygen vacancy defects (V o ) so as to reduce the defect-induced recombination loss of carriers at the SnO2 / perovskite interface, promote the extraction and transmission of interface carriers; meanwhile, the introduced lead interstitial defects (Pb i ) improve the conductivity of the prepared SnO2 electron transport layer, the application provides a new idea for the rapid synthesis of a SnO2 quantum dot solution and metal ion doping, and improves the photoelectric conversion efficiency of the carbon-based all-inorganic CsPbBr3 perovskite solar cell.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of perovskite solar cells, and particularly relates to a carbon-based all-inorganic CsPbBr3 perovskite solar cell and a preparation method thereof. BACKGROUND

[0002] Perovskite solar cells can be comparable to commercial silicon-based cells in terms of efficiency and cost, attracting extensive attention of researchers. As an important component of perovskite solar cell devices, the electron transport layer plays a crucial role in improving the efficiency of the devices. So far, commonly used electron transport layer materials include n-type semiconductors (such as TiO2, SnO2, ZnO, Zn2SnO4, BaSnO3) and organic substances (such as phenyl C61-butyric acid methyl ester [PCBM] and C60). Among them, SnO2 has the advantages of high transmittance, wide band gap, good charge mobility, appropriate band offset, low-temperature processing synthesis and good chemical stability, making SnO2 electron transport layer an ideal candidate for high-efficiency and stable perovskite solar cells. The method of preparing an electron transport layer by spin-coating SnO2 dispersion has been widely used, and this method has good effect and is suitable for large-scale production. However, the SnO2 electron transport layer has various intrinsic point defects (such as oxygen vacancies and tin vacancies, interstitial and anti-site defects) and exogenous doping defects, which mainly affect the electrical, optical properties and energy level structure of SnO2. As an n-type semiconductor, the main defects in SnO2 are tin interstitial defects (Sn i ) and oxygen vacancy defects (V o ), which make SnO2 have good conductivity as shallow donor levels. However, V o defects can easily hydroxylate the surface of SnO2, further generating unsaturated Sn dangling bonds, and then adsorbing O2 and H2O in the surrounding atmosphere, capturing electrons, and forming a barrier to electron transport. Therefore, in the present application, the defects of SnO2 are managed by synthesizing SnO2 quantum dot solution in an oxygen atmosphere, suppressing the generation of V o , and improving the performance of the device. At the same time, high concentration of oxygen promotes the synthesis process of SnO2 solution, shortening the reaction time. In addition, further use of Pb-doped SnO2 improves the electrical conductivity by introducing lead interstitial defects (Pb i ). SUMMARY

[0003] The purpose of the present application is to provide a carbon-based all-inorganic CsPbBr3 perovskite solar cell and a preparation method thereof. In the present application, SnO2 is defect-regulated in an oxygen atmosphere to reduce the surface V o, which reduces the interface carrier recombination. In addition, oxygen promotes the hydrolysis and dehydration oxidation process of SnO2, shortening the synthesis time of SnO2 quantum dot solution. At the same time, by doping, lead interstitial defects (Pb i ) are introduced, which effectively improves the conductivity of the SnO2 electron transport layer, promotes the transmission of interface carriers, and improves the photoelectric conversion efficiency of the carbon-based all-inorganic CsPbBr3 perovskite solar cell.

[0004] The preparation method of the carbon-based all-inorganic CsPbBr3 perovskite solar cell provided by the application comprises the following steps:

[0005] (1) Preparation of SnO2 quantum dot solution: 135.4-270.8 mg of SnCl2·2H2O, 45.1-90.1 mg of thiourea and 0.2-22 mg of PbBr2 are added to 5-10 mL of deionized water, and the mixture is stirred vigorously under oxygen or air atmosphere for 12-24 h to obtain a yellow clear solution; or 135.4-270.8 mg of SnCl2·2H2O and 45.1-90.1 mg of thiourea are added to 5-10 mL of deionized water, and the mixture is stirred vigorously under oxygen atmosphere for 12-24 h to obtain a yellow clear solution; then the mixture is filtered using a 0.22 μm PTFE filter head to obtain the SnO2 quantum dot solution;

[0006] (2) Preparation of FTO conductive glass substrate: the FTO conductive glass is sequentially ultrasonically treated with deionized water, anhydrous ethanol, acetone and isopropanol for 10-20 min, dried with nitrogen, and then subjected to plasma cleaning for 15-30 min to obtain the FTO conductive glass substrate;

[0007] (3) Preparation of SnO2 electron transport layer: the SnO2 quantum dot solution obtained in step (1) and the FTO conductive glass substrate obtained in step (2) are preheated at 60-90℃ for 5-10 min, then the SnO2 quantum dot solution is spin-coated on the FTO conductive glass substrate at a rotation speed of 1500-4000 rpm for 20-40 s, and then annealed at 170-220℃ for 30-90 min, and finally naturally cooled to room temperature, thereby obtaining a SnO2 electron transport layer with a thickness of 20-40 nm on the FTO conductive glass substrate;

[0008] (4) Preparation of CsPbBr3 perovskite photoactive layer by two-step method

[0009] ① 330-403.7 mg of PbBr2 is dissolved in 1 mL of N,N-dimethylformamide (DMF), heated and stirred at 60-90℃ for 3-8 hours to obtain a PbBr2 solution; 200-240 mg of CsBr is dissolved in 1 mL of deionized water to obtain a CsBr solution;

[0010] (2) the FTO conductive glass substrate obtained in step (1) is preheated at 70-100°C for 5-10 min, and then the SnO2 solution is spin-coated on the surface of the FTO conductive glass substrate at a spin speed of 1500-3000 rpm for 20-40 s, and then annealed at 70-100°C for 10-40 min, and then naturally cooled to room temperature, thereby obtaining a SnO2 electron transport layer;

[0011] (3) the PbBr2 solution is dropped on the surface of the SnO2 electron transport layer, and spin-coated after staying for 5-30 s at a spin speed of 1500-3000 rpm for 20-40 s, and then annealed at 240-280°C for 5-20 min, thereby obtaining a CsPbBr3 perovskite photoactive layer with a thickness of 400-650 nm on the SnO2 electron transport layer;

[0012] (5) the carbon paste is coated on the CsPbBr3 perovskite photoactive layer, and annealed at 100-120°C for 20-40 min, thereby obtaining a carbon electrode with a thickness of 5-20 μm, and thus obtaining a carbon-based all-inorganic CsPbBr3 perovskite solar cell.

[0013] Preferably, in step (1), the concentration of SnCl2·2H2O and thiourea is 0.1-0.15 M, the molar amount of PbBr2 is 0.2-1% of the molar amount of SnCl2, and the purity of SnCl2·2H2O is greater than or equal to 99.99%; the stirring temperature is 20-30°C, and the storage temperature of the obtained SnO2 quantum dot solution should be above 23°C;

[0014] Preferably, in step (3), the preheating temperature of the SnO2 solution and the substrate is 75-85°C, the spin speed is 1800-3000 rpm, and the spin time is 25-35 s; the annealing temperature is 190-210°C, and the annealing time is 50-70 min;

[0015] Preferably, in step (4), the concentration of PbBr2 and CsBr is 0.9-1.1 mol / L, the spin speed is 1800-2500 rpm, and the spin time is 25-35 s; the preheating temperature of the FTO conductive glass substrate and PbBr2 is 90-100°C, the annealing temperature is 90-100°C, and the annealing time is 20-35 min; the residence time of the CsBr aqueous solution on the PbBr2 layer is 15-25 s; the annealing temperature is 250-270°C, and the annealing time is 10-20 min;

[0016] Preferably, the carbon paste annealing temperature in step (5) is 100-110℃, the annealing time is 20-30min, the thickness of the carbon electrode is 10-20μm, and the conductive carbon paste model is: carbon paste MTW-CEC-003, ~50wt%, purchased from Mayituo.

[0017] The present application has the following advantages and beneficial effects: a rapid synthesis method of SnO2 quantum dot solution is proposed, which can be completed by using oxygen or air atmosphere synthesis and using PbBr2 doping. Compared with other SnO2 quantum dot solution synthesis, the use of oxygen in this patent promotes the hydrolysis dehydration oxidation process of SnCl2, accelerates the synthesis process of SnO2, shortens the reaction time, and reduces the generation of oxygen vacancy defects (V o ) to reduce the defect-induced recombination loss of carriers at the SnO2 / perovskite interface and promote the interface carrier extraction. At the same time, the introduced Pb i defects improve the conductivity of the prepared SnO2 electron transport layer, and the present application provides a new idea for the rapid synthesis of SnO2 quantum dot solution and metal ion doping. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is the Fourier infrared spectrum of SnO2 quantum dot solution prepared by example 1 and comparative example 1 at different reaction times;

[0019] Figure 2 is the fluorescence spectrum of SnO2 electron transport layer prepared by example 1, example 2, example 3 and comparative example 1, respectively;

[0020] Figure 3 is the conductivity curve of SnO2 electron transport layer prepared by example 1, example 2, example 3 and comparative example 1, respectively;

[0021] Figure 4 is the J-V curve of CsPbBr3 device prepared by example 1, example 2, example 3 and comparative example 1, respectively. DETAILED DESCRIPTION

[0022] The present application provides a method for rapid synthesis of SnO2 quantum dot solution and Pb-doped SnO2 by using oxygen atmosphere, which can regulate the defects of the prepared SnO2 electron transport layer, comprising the following steps:

[0023] Example 1 (no Pb doping, SnO2 quantum dot solution prepared under oxygen atmosphere):

[0024] (1) Preparation of SnO2 quantum dot solution: 203 mg of SnCl2·2H2O and 67.6 mg of thiourea were added to 6 mL of deionized water and stirred vigorously at 25 °C for 24 h under an oxygen atmosphere to obtain a yellow clear solution. The solution was then filtered with a 0.22 μm PTFE filter to obtain SnO2 quantum dot solution and stored in an environment above 23 °C.

[0025] (2) Preparation of FTO conductive glass substrate: FTO conductive glass was ultrasonically treated with deionized water, anhydrous ethanol, acetone and isopropanol for 15 min in sequence, dried with nitrogen and plasma cleaned for 20 min to obtain FTO conductive glass substrate.

[0026] (3) Preparation of SnO2 electron transport layer: The SnO2 quantum dot solution obtained in step (1) and the FTO conductive glass substrate obtained in step (2) are preheated at 80°C for 6 min. Then, the SnO2 quantum dot solution is spin-coated on the FTO conductive glass substrate at a speed of 2000 rpm for 30 s. Then, it is annealed at 200°C for 60 min. Finally, it is naturally cooled to room temperature, so as to obtain a SnO2 electron transport layer with a thickness of 30 nm on the FTO conductive glass substrate.

[0027] (4) Preparation of perovskite thin films using a two-step method

[0028] ① Dissolve 367 mg PbBr2 in 1 mL of N,N-dimethylformamide (DMF), heat and stir at 70 °C for 5 hours to obtain a PbBr2 solution; dissolve 212.8 mg CsBr in 1 mL of deionized water to obtain a CsBr solution;

[0029] ② The FTO conductive glass substrate and PbBr2 solution obtained in step (3) are preheated on a hot stage at 95°C for 10 min. Then, the PbBr2 solution is spin-coated onto the SnO2 electron transport layer on the surface of the FTO conductive glass substrate at a speed of 2000 rpm for 30 s. After spin-coating, the substrate is annealed on a hot stage at 95°C for 30 min and then naturally cooled to room temperature to obtain the PbBr2 layer.

[0030] ③ Apply CsBr aqueous solution to the surface of PbBr2 layer, leave for 20s, then spin coat at 2000rpm for 30s; then anneal at 270℃ for 15min to obtain a CsPbBr3 perovskite photoactive layer with a thickness of 600nm on SnO2 electron transport layer.

[0031] (5) Carbon paste (MTW-CEC-003, ~50wt%, purchased from Maituowei) was coated onto the CsPbBr3 perovskite photoactive layer and annealed at 100℃ for 20min. The thickness of the carbon electrode was 15μm, thus obtaining a carbon-based all-inorganic CsPbBr3 perovskite solar cell.

[0032] Example 2 (Pb doping, preparation of SnO2 quantum dot solution in air atmosphere):

[0033] (1) Preparation of Pb-doped SnO2 quantum dot solution: 203 mg SnCl2·2H2O, 67.6 mg thiourea and 3.3 mg PbBr2 were added to 6 mL of deionized water and stirred vigorously at 25 °C for 24 h in air atmosphere to obtain a yellow clear solution. The solution was then filtered with a 0.22 μm PTFE filter to obtain Pb-doped SnO2 quantum dot solution and stored in an environment above 23 °C.

[0034] (2) Preparation of FTO conductive glass substrate: FTO conductive glass was ultrasonically treated with deionized water, anhydrous ethanol, acetone and isopropanol for 15 min in sequence, dried with nitrogen and plasma cleaned for 20 min to obtain FTO conductive glass substrate.

[0035] (3) Preparation of Pb-doped SnO2 electron transport layer: The Pb-doped SnO2 quantum dot solution obtained in step (1) and the FTO conductive glass substrate obtained in step (2) are preheated at 80°C for 6 min. Then, the SnO2 quantum dot solution is spin-coated on the FTO conductive glass substrate at a speed of 2000 rpm for 30 s. Then, it is annealed at 200°C for 60 min. Finally, it is naturally cooled to room temperature, so as to obtain a Pb-doped SnO2 electron transport layer with a thickness of 30 nm on the FTO conductive glass substrate.

[0036] (4) Preparation of perovskite thin films using a two-step method

[0037] ① Dissolve 367 mg PbBr2 in 1 mL of N,N-dimethylformamide (DMF), heat and stir at 70 °C for 5 hours to obtain a PbBr2 solution; dissolve 212.8 mg CsBr in 1 mL of deionized water to obtain a CsBr solution;

[0038] ② The FTO conductive glass substrate and PbBr2 solution obtained in step (3) are preheated on a hot stage at 95°C for 10 min. Then, the PbBr2 solution is spin-coated onto the SnO2 electron transport layer on the surface of the FTO conductive glass substrate at a speed of 2000 rpm for 30 s. After spin-coating, the substrate is annealed on a hot stage at 95°C for 30 min and then naturally cooled to room temperature to obtain the PbBr2 layer.

[0039] ③ Spin-coat the CsBr aqueous solution onto the surface of the PbBr2 layer, hold for 20 seconds, then start spin coating at 2000 rpm for 30 seconds; then anneal at 270℃ for 15 minutes to obtain a CsPbBr3 perovskite photoactive layer with a thickness of 600 nm on the SnO2 electron transport layer.

[0040] (5) Carbon paste (MTW-CEC-003, ~50wt%, purchased from Maituowei) was coated onto the CsPbBr3 perovskite photoactive layer and annealed at 100℃ for 20min. The thickness of the carbon electrode was 15μm, thus obtaining a carbon-based all-inorganic CsPbBr3 perovskite solar cell.

[0041] Example 3 (Pb doping, preparation of SnO2 quantum dot solution under oxygen atmosphere):

[0042] (1) Preparation of Pb-doped SnO2 quantum dot solution: 203 mg SnCl2·2H2O, 67.6 mg thiourea and 3.3 mg PbBr2 were added to 6 mL of deionized water and stirred vigorously at 25 °C for 24 h under an oxygen atmosphere to obtain a yellow clear solution. The solution was then filtered with a 0.22 μm PTFE filter to obtain the Pb-doped SnO2 quantum dot solution and stored in an environment above 23 °C.

[0043] (2) Preparation of FTO conductive glass substrate: FTO conductive glass was ultrasonically treated with deionized water, anhydrous ethanol, acetone and isopropanol for 15 min in sequence, dried with nitrogen and plasma cleaned for 20 min to obtain FTO conductive glass substrate.

[0044] (3) Preparation of Pb-doped SnO2 electron transport layer: The Pb-doped SnO2 quantum dot solution obtained in step (1) and the FTO conductive glass substrate obtained in step (2) are preheated at 80°C for 6 min. Then, the SnO2 quantum dot solution is spin-coated on the FTO conductive glass substrate at a speed of 2000 rpm for 30 s. Then, it is annealed at 200°C for 60 min. Finally, it is naturally cooled to room temperature, so as to obtain a Pb-doped SnO2 electron transport layer with a thickness of 30 nm on the FTO conductive glass substrate.

[0045] (4) Preparation of perovskite thin films using a two-step method

[0046] ① Dissolve 367 mg PbBr2 in 1 mL of N,N-dimethylformamide (DMF), heat and stir at 70 °C for 5 hours to obtain a PbBr2 solution; dissolve 212.8 mg CsBr in 1 mL of deionized water to obtain a CsBr solution;

[0047] ② The FTO conductive glass substrate and PbBr2 solution obtained in step (3) are preheated on a hot stage at 95°C for 10 min. Then, the PbBr2 solution is spin-coated onto the SnO2 electron transport layer on the surface of the FTO conductive glass substrate at a speed of 2000 rpm for 30 s. After spin-coating, the substrate is annealed on a hot stage at 95°C for 30 min and then naturally cooled to room temperature to obtain the PbBr2 layer.

[0048] ③ Apply CsBr aqueous solution to the surface of PbBr2 layer, leave for 20s, then spin coat at 2000rpm for 30s; then anneal at 270℃ for 15min to obtain a CsPbBr3 perovskite photoactive layer with a thickness of 600nm on SnO2 electron transport layer.

[0049] (5) Carbon paste (MTW-CEC-003, ~50wt%, purchased from Maituowei) was coated onto the CsPbBr3 perovskite photoactive layer and annealed at 100℃ for 20min. The thickness of the carbon electrode was 15μm, thus obtaining a carbon-based all-inorganic CsPbBr3 perovskite solar cell.

[0050] Comparative Example 1 (SnO2 quantum dot solution prepared in air atmosphere without Pb doping):

[0051] (1) Preparation of SnO2 quantum dot solution: 203 mg of SnCl2·2H2O and 67.6 mg of thiourea were added to 6 mL of deionized water and stirred vigorously at 25 °C for 24 h in air atmosphere to obtain a yellow clear solution. The solution was then filtered with a 0.22 μm PTFE filter to obtain SnO2 quantum dot solution and stored in an environment above 23 °C.

[0052] (2) Preparation of FTO conductive glass substrate: FTO conductive glass was ultrasonically treated with deionized water, anhydrous ethanol, acetone and isopropanol for 15 min in sequence, dried with nitrogen and plasma cleaned for 20 min to obtain FTO conductive glass substrate.

[0053] (3) Preparation of SnO2 electron transport layer: The SnO2 quantum dot solution obtained in step (1) and the FTO conductive glass substrate obtained in step (2) are preheated at 80°C for 6 min. Then, the SnO2 quantum dot solution is spin-coated on the FTO conductive glass substrate at a speed of 2000 rpm for 30 s. Then, it is annealed at 200°C for 60 min. Finally, it is naturally cooled to room temperature, so as to obtain a SnO2 electron transport layer with a thickness of 30 nm on the FTO conductive glass substrate.

[0054] (4) Preparation of perovskite thin films using a two-step method

[0055] ① Dissolve 367 mg PbBr2 in 1 mL of N,N-dimethylformamide (DMF), heat and stir at 70 °C for 5 hours to obtain a PbBr2 solution; dissolve 212.8 mg CsBr in 1 mL of deionized water to obtain a CsBr solution;

[0056] ② The FTO conductive glass substrate and PbBr2 solution obtained in step (3) are preheated on a hot stage at 95°C for 10 min. Then, the PbBr2 solution is spin-coated onto the SnO2 electron transport layer on the surface of the FTO conductive glass substrate at a speed of 2000 rpm for 30 s. After spin-coating, the substrate is annealed on a hot stage at 95°C for 30 min and then naturally cooled to room temperature to obtain the PbBr2 layer.

[0057] ③ Apply CsBr aqueous solution to the surface of PbBr2 layer, leave for 20s, then spin coat at 2000rpm for 30s; then anneal at 270℃ for 15min to obtain a CsPbBr3 perovskite photoactive layer with a thickness of 600nm on SnO2 electron transport layer.

[0058] (5) Carbon paste (MTW-CEC-003, ~50wt%, purchased from Maituowei) was coated onto the CsPbBr3 perovskite photoactive layer and annealed at 100℃ for 20min. The thickness of the carbon electrode was 15μm, thus obtaining a carbon-based all-inorganic CsPbBr3 perovskite solar cell.

[0059] The Fourier transform infrared spectra of the SnO2 quantum dot solutions synthesized in Example 1 and Comparative Example 1 under air and oxygen atmospheres at different times are as follows: Figure 1 As shown, at 1370cm -1 The peak at [value] represents the characteristic peak of Sn(OH)2 produced by the hydrolysis of SnCl2. The characteristic peak of Sn(OH)2 in the SnO2 quantum dot solution synthesized in air reaches its maximum absorption after 1.5 h and gradually disappears after 1.5–3 h. This indicates that the degree of SnCl2 hydrolysis is highest after 1.5 h, and dehydration and oxidation begin after 1.5–3 h. In contrast, the characteristic peak of Sn(OH)2 in the SnO2 quantum dot solution synthesized in Example 1 under an oxygen atmosphere reaches its maximum after 0.5 h and gradually disappears after 0.5–1 h, tending to stabilize. This indicates that, compared to Comparative Example 1, oxygen treatment not only accelerates the process of SnCl2 hydrolysis to Sn(OH)2 but also promotes the process of Sn(OH)2 dehydration and oxidation to SnO2.

[0060] The electron transport layer PL spectra of SnO2 prepared in Examples 1, 2, and 3 and Comparative Example 1 are as follows: Figure 2 As shown, the synthesis of SnO2 under an oxygen atmosphere can effectively reduce V. o The generation of Pb-doped SnO2 electron transport layers; at the same time, the Pb-doped SnO2 electron transport layer also has less V o .

[0061] The conductivity of the SnO2 electron transport layer prepared in Examples 1, 2, and 3 and Comparative Example 1 is as follows: Figure 3As shown, SnO2 synthesized under an oxygen atmosphere is due to V o As the amount of Pb decreases, the conductivity decreases accordingly. However, the conductivity increases after Pb doping with SnO2. This is because Pb doping with SnO2 introduces Pb... i The defects improve the conductivity of the SnO2 electron transport layer, which in turn facilitates the transport of charge carriers.

[0062] SnO2: Represents an air atmosphere; SnO2-O2: Represents an oxygen atmosphere; Pb-SnO2: Represents Pb doping and an air atmosphere; Pb-SnO2-O2: Represents Pb doping and an oxygen atmosphere;

[0063] The photovoltaic parameters and JV characteristic curves of the perovskite solar cells of Examples 1, 2, and 3 and Comparative Example 1 are shown in Table 1 and 2. Figure 4 As shown.

[0064] Table 1. Photovoltaic performance parameters of perovskite solar cells in the examples and comparative examples.

[0065]

[0066] As shown in Table 1, the photovoltaic performance of the perovskite solar cells prepared in Examples 1-3 was improved. This is attributed to the reduction of Vo in the SnO2 electron transport layer. o The increased conductivity and carrier transport are improved.

[0067] The above embodiments are preferred embodiments of the present invention, but the specific embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a carbon-based all-inorganic CsPbBr3 perovskite solar cell, comprising the following steps: (1) preparing a SnO2 quantum dot solution: adding 135.4-270.8 mg of SnCl2·2H2O, 45.1-90.1 mg of thiourea, and 0.2-22 mg of PbBr2 into 5-10 mL of deionized water, and stirring vigorously under an oxygen or air atmosphere for 12-24 h to obtain a yellow clear solution; or adding 135.4-270.8 mg of SnCl2·2H2O and 45.1-90.1 mg of thiourea into 5-10 mL of deionized water, and stirring vigorously under an oxygen atmosphere for 12-24 h to obtain a yellow clear solution; and then filtering using a 0.22 μm PTFE filter head to obtain the SnO2 quantum dot solution; (2) preparing an FTO conductive glass substrate: ultrasonically treating FTO conductive glass with deionized water, anhydrous ethanol, acetone, and isopropanol for 10-20 min, respectively, blowing dry with nitrogen, and then performing plasma cleaning for 15-30 min to obtain the FTO conductive glass substrate; (3) preparing a SnO2 electron transport layer: preheating the SnO2 quantum dot solution obtained in step (1) and the FTO conductive glass substrate obtained in step (2) at 60-90 °C for 5-10 min, and then spin-coating the Pb-doped SnO2 quantum dot solution on the FTO conductive glass substrate at a rotation speed of 1500-4000 rpm for 20-40 s, and annealing at 170-220 °C for 30-90 min, and finally naturally cooling to room temperature, thereby obtaining a SnO2 electron transport layer with a thickness of 20-40 nm on the FTO conductive glass substrate; (4) preparing a CsPbBr3 perovskite photoactive layer by a two-step method ① dissolving 330-403.7 mg of PbBr2 in 1 mL of N,N-dimethylformamide (DMF), heating and stirring at 60-90 °C for 3-8 h to obtain a PbBr2 solution; and dissolving 200-240 mg of CsBr in 1 mL of deionized water to obtain a CsBr solution; ② preheating the FTO conductive glass substrate obtained in step (3) and the PbBr2 solution at 70-100 °C for 5-10 min, and then spin-coating the PbBr2 solution on the SnO2 electron transport layer on the surface of the FTO conductive glass substrate at a rotation speed of 1500-3000 rpm for 20-40 s, and annealing at 70-100 °C for 10-40 min after spin-coating, and then naturally cooling to room temperature, thereby obtaining a PbBr2 layer; ③ dropping the CsBr solution on the surface of the PbBr2 layer, and spin-coating after 5-30 s, at a rotation speed of 1500-3000 rpm for 20-40 s; and then annealing at 240-280 °C for 5-20 min, thereby obtaining a CsPbBr3 perovskite photoactive layer with a thickness of 400-650 nm on the SnO2 electron transport layer. (5) The carbon paste is scraped on the CsPbBr3 perovskite photoactive layer, and annealed at 100-120℃ for 20-40min, to obtain a carbon electrode with a thickness of 5-20μm, thereby obtaining a carbon-based all-inorganic CsPbBr3 perovskite solar cell.

2. The preparation method of a carbon-based all-inorganic CsPbBr3 perovskite solar cell according to claim 1, characterized in that: In step (1), the concentration of SnCl2·2H2O and thiourea is 0.1-0.15M, and the molar amount of PbBr2 is 0.2-1% of the molar amount of SnCl2; the stirring temperature is 20-30℃, and the storage temperature of the obtained SnO2 quantum dot solution should be above 23℃.

3. The method for preparing a carbon-based all-inorganic CsPbBr3 perovskite solar cell as described in claim 1, characterized in that: In step (3), the preheating temperature of the FTO conductive glass substrate of the SnO2 quantum dot solution is 75-85℃; the spin coating speed is 1800-3000rpm, and the spin coating time is 25-35s; the annealing temperature is 190-210℃, and the annealing time is 50-70min.

4. The method for preparing a carbon-based all-inorganic CsPbBr3 perovskite solar cell as described in claim 1, characterized in that: In step (4), the concentration of PbBr2 and CsBr is 0.9-1.1mol / L, the spin coating speed is 1800-2500rpm, the spin coating time is 25-35s, the preheating temperature of the FTO conductive glass substrate and PbBr2 is 90-100℃, the annealing temperature is 90-100℃, and the annealing time is 20-35min; the residence time of the CsBr aqueous solution on the PbBr2 layer is 15-25s, the annealing temperature is 250-270℃, and the annealing time is 10-20min.

5. The method for preparing a carbon-based all-inorganic CsPbBr3 perovskite solar cell as described in claim 1, characterized in that: In step (5), the annealing temperature of the carbon paste is 100-110℃, the annealing time is 20-30min, and the thickness of the carbon electrode is 10-20μm.

6. A carbon-based all-inorganic CsPbBr3 perovskite solar cell, characterized in that: is prepared by the method of any one of claims 1-5.

Images