A tin-containing perovskite solar cell doped with 3-trifluoromethylpyridine and a preparation method thereof

Abstract

The application discloses a kind of doped 3-trifluoromethylpyridine's tin-containing perovskite solar cell and preparation method thereof, preparation process includes: cleaning transparent conductive substrate is pretreated, deposition hole transport layer and carry out annealing treatment, 3-TFMP is added to tin-containing perovskite precursor solution and is stirred uniformly, and is deposited on the surface of hole transport layer, tin-containing perovskite active layer is obtained by annealing treatment, continue to deposit electron transport layer, hole blocking layer and top electrode in sequence, obtain tin-containing perovskite solar cell based on 3-TFMP doped perovskite after.The additive molecule containing strong electron-withdrawing functional group trifluoromethyl of the application can interact with SnI2 coordination in perovskite precursor to form complex (i.e. tin adduct), improve the redox potential of tin adduct, reduce highest occupied molecular orbital (HOMO) energy level, to inhibit stannous ion (Sn 2+ ) oxidation, improve the photoelectric conversion efficiency and stability of perovskite solar cell.

Description

Technical Field

[0001] The present invention belongs to the technical field of perovskite solar cell manufacturing, and in particular relates to a tin-containing perovskite solar cell doped with 3-trifluoromethylpyridine and a preparation method thereof. Background Art

[0002] Efficient utilization of solar energy has always been a focus of researchers. Metal halide perovskites have become the most promising materials for the next generation of thin-film solar cells due to their excellent optoelectronic properties. Currently, the power conversion efficiency (PCE) of single-junction perovskite solar cells (PSCs) has reached 26.1%. However, due to their ionic crystal nature, perovskites generally exhibit poor stability, especially in the presence of environmental substances.

[0003] In recent years, tin-based perovskites have attracted widespread attention due to their low toxicity and narrow band gap. In particular, tin-lead mixed metal halide perovskites can obtain a narrow optical band gap of about 1.2eV, which is crucial for the development of all-perovskite tandem solar cells. By combining narrow-bandgap tin-lead mixed perovskites with wide-bandgap lead-based perovskites to prepare tandem devices, it is expected to break the theoretical efficiency limit of single-junction solar cells. However, tin-based perovskites inevitably bring two key problems: one is the stannous ion (Sn 2+ ) is particularly unstable and easily oxidized to form Sn 4+ Secondly, tin-based perovskites crystallize faster, resulting in poor film quality. These problems are accompanied by the generation of a large number of defects in the perovskite, which changes the carrier type and thus aggravates carrier recombination in the device, leading to performance degradation of tin-containing PSCs. Therefore, despite having an ideal band gap, the performance of tin-containing PSCs is currently not particularly satisfactory.

[0004] As can be seen from the above, inhibiting the oxidation of tin perovskites, reducing the defects present in the perovskite, and obtaining high-quality perovskite films are key to improving the photovoltaic performance and stability of tin-containing PSCs. Among the various strategies currently developed, additive engineering is considered a simple and effective method to improve the performance of PSC devices. However, current research on tin-containing perovskite additives has focused more on reducing organic compounds. Therefore, to further enhance the photovoltaic performance and stability of tin-containing PSCs, it is urgent to develop a new, efficient additive molecule that can be introduced into the perovskite layer to optimize the properties of the above films. Summary of the Invention

[0005] In view of the above problems, the object of the present invention is to provide a tin-containing perovskite solar cell doped with 3-trifluoromethylpyridine and a preparation method thereof.

[0006] Specific technical solutions:

[0007] A method for preparing a tin-containing perovskite solar cell doped with 3-trifluoromethylpyridine comprises the following steps:

[0008] 1) Ultrasonic cleaning of the transparent conductive substrate, drying the transparent conductive substrate with a nitrogen stream before use, and then treating the surface of the transparent conductive substrate with a plasma cleaner or ozone;

[0009] 2) depositing a hole transport layer HTL solution on the surface of the transparent conductive substrate treated in step 1), and performing annealing treatment to obtain an HTL film;

[0010] 3) Adding 3-trifluoromethylpyridine (3-TFMP) to a tin-containing perovskite precursor solution and stirring uniformly to prepare a 3-trifluoromethylpyridine-doped tin-containing perovskite precursor solution, depositing the solution on the surface of the HTL film, and annealing to obtain a tin-containing perovskite active layer;

[0011] 4) subsequently depositing an electron transport layer and a hole blocking layer on the surface of the tin-containing perovskite active layer obtained in step 3);

[0012] 5) depositing a top electrode on the surface of the thin film obtained in step 4), and finally obtaining a tin-containing perovskite solar cell based on 3-trifluoromethylpyridine-doped perovskite.

[0013] Furthermore, the deposition method is one of spin coating, blade coating, inkjet printing, slit coating, and vacuum evaporation, or a combination of multiple methods.

[0014] Furthermore, the transparent conductive substrate in step 1) is Glass / ITO or FTO, plastic flexible substrate / ITO or FTO, and the transparent conductive substrate is ultrasonically cleaned using distilled water, acetone, and isopropyl alcohol solvents in sequence.

[0015] Furthermore, the HTL solution in step 2) is a mixed material of one or more of PEDOT:PSS, PTAA, MeO-2PACz, and 4PACz.

[0016] Furthermore, the HTL solution is spin-coated on the surface-treated transparent conductive substrate, and then annealed to obtain a hole transport layer. The spin-coating speed is 5000-6000 rpm and the spin-coating time is 30-40 seconds. The annealing temperature is 90-110° C. and the annealing time is 5-10 minutes.

[0017] The tin-containing perovskite precursor solution in step 3) is any organic-inorganic hybrid perovskite or inorganic perovskite containing metallic tin, and the thickness of the tin-containing perovskite active layer is 600-800 nm.

[0018] Preferably, the tin-containing perovskite precursor solution in step 3) is FAx MA 1-x Sn y Pb 1-y I3,0≤x≤1,0 <y≤1或CsSn x Pb 1-x I 2.7 Br 0.3 , 0 <x≤1。

[0019] Preferably, when the tin-containing perovskite precursor solution is FA 0.7 MA 0.3 Sn 0.5 Pb 0.5 I3, the specific process is: dissolving a mixture of FAI, MAI, SnI2, PbI2 and SnF2 in a mixed solvent of DMF and DMSO with a volume ratio of 2:1-4:1 to prepare a perovskite precursor solution with a concentration of 1.5-2.5M and a SnF2 content of 5-15 mol% of SnI2.

[0020] Preferably, when the tin-containing perovskite precursor solution is CsPb 0.5 Sn 0.5 I 2.7 Br 0.3 The specific process is as follows: CsI, CsBr, PbBr2 and PbI2 are dissolved in a mixed solvent of DMF and DMSO (v / v, 4:1) to form 0.8M CsPbI 2.4 Br 0.6 CsI, SnI2 and SnF2 with a molar ratio of 1:1:0.1 were dissolved in a mixed solvent of DMF and DMSO (v / v, 4:1) to form a 0.8 M CsSnI3 precursor solution. 2.4 Br 0.6 and CsSnI3 precursor solution in a volume ratio of 1:1 to prepare CsPb 0.5 Sn 0.5 I 2.7 Br 0.3 Precursor solution.

[0021] Furthermore, in step 3), the doping amount of 3-trifluoromethylpyridine is 1-5 mol% of the tin-containing perovskite precursor solution, 3-trifluoromethylpyridine is added to the tin-containing perovskite precursor solution and stirred for 0.5-1.5 hours, and then filtered through a polytetrafluoroethylene membrane to obtain a 3-trifluoromethylpyridine-doped tin-containing perovskite precursor solution.

[0022] Furthermore, in step 3), two-step spin coating deposition is performed, first at a speed of 500-1000 rpm for 5-10 seconds, and then at a speed of 4000-5000 rpm for 30-50 seconds. 10-20 seconds before the end of the second spin coating, 100-300 μL of ethyl acetate antisolvent is dripped onto the rotating substrate, and then the substrate is annealed at a temperature of 90-110°C for 5-20 minutes to obtain the final perovskite film.

[0023] Furthermore, the electron transport layer in step 4) is PC 61 BM, PC 71 BM, C 60 、C 70 One or more mixed materials, the hole blocking layer is BCP.

[0024] Furthermore, the top electrode in step 5) is a combination of one or more materials selected from Ag, Au, Cu, AZO, carbon materials, and conductive polymers.

[0025] A tin-containing perovskite solar cell doped with 3-trifluoromethylpyridine prepared by the above preparation method.

[0026] The beneficial effects of the present invention are:

[0027] (1) The present invention provides a method for preparing a tin-containing perovskite solar cell doped with 3-trifluoromethylpyridine (3-TFMP), wherein a perovskite film is prepared by dissolving a perovskite precursor solution containing 3-TFMP. The trifluoro-substituted (having strong electron-withdrawing properties) additive molecule can interact with the SnI2 in the perovskite precursor to form a complex (i.e., a tin adduct), thereby increasing the redox potential of the tin adduct and reducing the highest occupied molecular orbital (HOMO) energy level. In addition, the introduction of the fluorine-substituted molecule leads to an increase in the ionization potential of the perovskite structure, thereby significantly suppressing the stannous ion (Sn) in the perovskite precursor solution and the film. 2+ ) oxidation, thereby reducing the defect state density, suppressing non-radiative recombination in the perovskite and extending the carrier lifetime. Ultimately, the photoelectric conversion efficiency and stability of perovskite solar cells are significantly improved.

[0028] (2) The present invention provides a method for preparing a 3-TFMP-doped tin-containing perovskite solar cell, wherein a perovskite film is prepared using a perovskite precursor solution in which 3-TFMP is dissolved. The 3-TFMP ligand molecule interacts with SnI2 via a pyridine group to extend the time window for perovskite crystallization, thereby preparing a perovskite film with better crystallinity, fewer grain boundaries, and lower residual stress. In addition, the surface morphology and crystallinity of the perovskite active layer can be adjusted by adjusting the amount of 3-TFMP added, thereby affecting the light absorption performance, the transmission and collection efficiency of photogenerated carriers, and the stability of the perovskite film, thereby providing a new method for preparing high-efficiency and high-stability tin-containing perovskite solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Steady-state fluorescence spectra of tin-containing perovskite films doped with 3-trifluoromethylpyridine and undoped with 3-trifluoromethylpyridine;

[0030] Figure 2 JV curves of tin-containing perovskite single hole carrier devices doped with 3-trifluoromethylpyridine and undoped with 3-trifluoromethylpyridine;

[0031] Figure 3 Surface SEM images of tin-containing perovskite films doped with 3-trifluoromethylpyridine and undoped with 3-trifluoromethylpyridine;

[0032] Figure 4 JV curves of tin-containing perovskite solar cells doped with 3-trifluoromethylpyridine and undoped with 3-trifluoromethylpyridine;

[0033] Figure 5 A comparison chart of the stability of tin-containing perovskite solar cells doped with 3-trifluoromethylpyridine and without 3-trifluoromethylpyridine. DETAILED DESCRIPTION

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments, but the protection scope of the present invention is not limited thereto.

[0035] Example 1

[0036] Based on Glass / ITO / PEDOT:PSS / 3-trifluoromethylpyridine doped perovskite / C 60 The preparation process of tin-lead perovskite solar cells with / BCP / Cu device structure is as follows:

[0037] Step 1: Use distilled water, acetone, and isopropyl alcohol solvents to ultrasonically clean the Glass / ITO transparent conductive anode substrate for 30 minutes in sequence, use a nitrogen flow to blow dry the anode substrate, and then use a plasma cleaning machine to treat the substrate surface for 10 minutes.

[0038] Step 2: Spin-coating the PEDOT:PSS solution on the surface-treated anode substrate, and then annealing to obtain the hole transport layer; wherein the spin-coating speed is 5000 rpm, the spin-coating time is 40 seconds, and the annealing temperature is 110° C., and the annealing time is 10 minutes.

[0039] Step 3: Spin-coat the perovskite precursor solution on the surface of the hole transport layer. The perovskite active layer is FA 0.7 MA 0.3 Sn 0.5 Pb 0.5 I3, the specific process is as follows: a mixture of FAI, MAI, SnI2, PbI2 and SnF2 is dissolved in a mixed solvent of DMF and DMSO with a volume ratio of 3:1 to prepare a perovskite precursor solution with a concentration of 2M and a SnF2 content of 10 mol% of SnI2. Subsequently, 2 mol% (relative to the proportion of the perovskite precursor solution) of 3-trifluoromethylpyridine is added to the perovskite precursor solution. The precursor solution is stirred at room temperature for 0.5 h, then filtered through a polytetrafluoroethylene membrane with a pore size of 0.22 μm, and the perovskite active layer is deposited by a two-step spin coating process: (1) 800 rpm for 10 seconds, (2) 5000 rpm for 30 seconds, and 15 seconds before the end of the second spin coating step, 300 μL of ethyl acetate antisolvent is dripped on the rotating substrate, and then the substrate is annealed to obtain the final tin-containing perovskite film, with an annealing temperature of 100 ° C and a time of 10 minutes.

[0040] Step 4: Evaporate the electron transport layer C on the surface of the above Sn-Pb perovskite active layer 60 , the thickness of which is 25nm; and a vapor-deposited hole blocking layer BCP, the thickness of which is 6nm;

[0041] Step 5: Vapor-deposit a cathode electrode layer of Cu on the surface of the hole blocking layer to a thickness of 90 nm;

[0042] After the above steps are completed, a tin-lead perovskite solar cell with a perovskite layer doped with 3-trifluoromethylpyridine is obtained.

[0043] Example 2

[0044] Based on Glass / ITO / PEDOT:PSS / Perovskite / C 60 The preparation process of tin-lead perovskite solar cells with / BCP / Cu device structure is as follows:

[0045] Step 1: Use distilled water, acetone, and isopropyl alcohol solvents to ultrasonically clean the Glass / ITO transparent conductive anode substrate for 30 minutes in sequence, use a nitrogen flow to blow dry the anode substrate, and then use a plasma cleaning machine to treat the substrate surface for 10 minutes.

[0046] Step 2: Spin-coating the PEDOT:PSS solution on the surface-treated anode substrate, and then annealing to obtain the hole transport layer; wherein the spin-coating speed is 5000 rpm, the spin-coating time is 40 seconds, and the annealing temperature is 110° C., and the annealing time is 10 minutes.

[0047] Step 3: Spin-coat the perovskite precursor solution on the surface of the hole transport layer. The perovskite active layer is FA 0.7 MA 0.3 Sn 0.5 Pb 0.5 I3, the specific process is as follows: a mixture of FAI, MAI, SnI2, PbI2 and SnF2 is dissolved in a mixed solvent of DMF and DMSO with a volume ratio of 3:1 to prepare a perovskite precursor solution with a concentration of 2M and a SnF2 content of 10 mol% of SnI2. The precursor mixed solution is stirred at room temperature for 0.5 h, then filtered through a polytetrafluoroethylene membrane with a pore size of 0.22 μm, and the perovskite active layer is deposited by a two-step spin coating process: (1) running at 800 rpm for 10 seconds, (2) running at 5000 rpm for 30 seconds, and 15 seconds before the end of the second spin coating step, 300 μL of ethyl acetate antisolvent is dripped on the rotating substrate, and then the substrate is annealed to obtain the final tin-containing perovskite film, with an annealing temperature of 100 ° C and a time of 10 minutes.

[0048] Step 4: Evaporate the electron transport layer C on the surface of the above Sn-Pb perovskite active layer 60 , the thickness of which is 25nm; and a vapor-deposited hole blocking layer BCP, the thickness of which is 6nm;

[0049] Step 5: Vapor-deposit a cathode electrode layer of Cu on the surface of the hole blocking layer to a thickness of 90 nm;

[0050] After the above steps are completed, a tin-lead perovskite solar cell without a perovskite layer is obtained.

[0051] Figure 1 It can be seen that the 3-TFMP-doped SnPb perovskite film has a high steady-state fluorescence intensity, indicating that the perovskite film has lower defect-induced non-radiative recombination. Figure 2 The JV curve of the single hole carrier device shows that the 3-TFMP-doped SnPb perovskite film has a lower V TFL, indicating that the doped film has a lower defect state density, indicating that the oxidation of stannous ions is effectively suppressed, which once again verifies that 3-TFMP doping has reduced non-radiative recombination phenomena. Figure 3 The SEM surface morphology shows that the 3-TFMP-doped Sn-Pb perovskite film has relatively larger grains and fewer grain boundaries, indicating that the perovskite crystallinity is improved. Figure 4 The results show that the tin-lead perovskite solar cells doped with 3-TFMP have higher open circuit voltage, short circuit current, fill factor and final photoelectric conversion efficiency, indicating that the introduction of 3-TFMP can suppress the energy loss caused by non-radiative recombination of the device, improve the efficiency of carrier transport and collection, and promote light absorption. Figure 5 It can be seen intuitively that the doped perovskite solar cells can maintain a higher initial efficiency ratio over time, indicating that the stability of perovskite solar cells is significantly improved by introducing 3-TFMP as an antioxidant additive in the tin-lead perovskite active layer.

[0052] Example 3

[0053] Based on Glass / ITO / PEDOT:PSS / 3-trifluoromethylpyridine doped perovskite / C 60 Preparation of SnPb perovskite solar cells with / BCP / Cu device structure

[0054] The amount of 3-trifluoromethylpyridine added to the perovskite precursor mixed solution in step 3 of Example 1 was changed to 1 mol %, while other operating conditions remained unchanged.

[0055] Example 4

[0056] Based on Glass / ITO / PEDOT:PSS / 3-trifluoromethylpyridine doped perovskite / C 60 Preparation of SnPb perovskite solar cells with / BCP / Cu device structure

[0057] The amount of 3-trifluoromethylpyridine added to the perovskite precursor mixed solution in step 3 of Example 1 was changed to 4 mol %, while other operating conditions remained unchanged.

[0058] Table 1 Comparison of parameters of tin-lead perovskite solar cells prepared in Examples 1-4

[0059]

[0060] The purpose of Example 1, Example 3 and Example 4 is to show the effect of different 3-trifluoromethylpyridine doping amounts on the photoelectric conversion efficiency of the final device. Compared with Example 1, Example 3 and Example 4 respectively add 2 mol%, 1 mol%, and 4 mol% of 3-trifluoromethylpyridine to a 2M tin-lead perovskite precursor mixed solution to obtain a perovskite precursor solution with a gradient doping amount. It can be found from Table 1 that in Example 1, when the doping amount of 3-trifluoromethylpyridine is 2 mol%, thanks to the effect of 3-trifluoromethylpyridine on the Sn-lead perovskite 2+ Oxidation inhibition and film crystallization modulation reduce the defects on the surface and grain boundaries of tin-lead perovskite, improve the film quality, significantly reduce the energy loss caused by non-radiative recombination, and the device has the highest open circuit voltage (V oc ), short-circuit current (J sc ), fill factor (FF) and the final photoelectric conversion efficiency; at the same time, compared with Example 2, various parameters of Example 3 and Example 4 are improved to varying degrees, but the effects are not as good as Example 1, so according to the experimental results, it is determined that the additive used in Example 1 is the optimal doping amount.

[0061] Example 5

[0062] Based on Glass / ITO / PEDOT:PSS / 3-trifluoromethylpyridine doped perovskite / C 60 The preparation process of pure inorganic tin-lead perovskite solar cells with / BCP / Cu device structure is as follows:

[0063] Step 1: Use distilled water, acetone, and isopropyl alcohol solvents to ultrasonically clean the Glass / ITO transparent conductive anode substrate for 30 minutes in sequence, use a nitrogen flow to blow dry the anode substrate, and then use a plasma cleaning machine to treat the substrate surface for 10 minutes.

[0064] Step 2: Spin-coating the PEDOT:PSS solution on the surface-treated anode substrate, and then annealing to obtain the hole transport layer; wherein the spin-coating speed is 5000 rpm, the spin-coating time is 40 seconds, and the annealing temperature is 110° C., and the annealing time is 10 minutes.

[0065] Step 3: Spin-coat the perovskite precursor solution on the surface of the hole transport layer. The perovskite active layer is CsPb 0.5 Sn 0.5 I 2.7 Br 0.3 The specific process is as follows: CsI, CsBr, PbBr2 and PbI2 are dissolved in a mixed solvent of DMF and DMSO (v / v, 4:1) to form 0.8M CsPbI 2.4 Br 0.6CsI, SnI2 and SnF2 with a molar ratio of 1:1:0.1 were dissolved in a mixed solvent of DMF and DMSO (v / v, 4:1) to form a 0.8M CsSnI3 precursor solution. 2.4 Br 0.6 and CsSnI3 precursor solution in a volume ratio of 1:1 to prepare CsPb 0.5 Sn 0.5 I 2.7 Br 0.3 Precursor solution. Subsequently, 3.5 mol% (relative to the proportion of the perovskite precursor solution) of 3-trifluoromethylpyridine was added to the perovskite precursor solution. The precursor solution was stirred at room temperature for 0.5 h, then filtered through a polytetrafluoroethylene membrane with a pore size of 0.22 μm, and the perovskite active layer was deposited by a two-step spin coating process: (1) running at 1000 rpm for 10 seconds, (2) running at 5000 rpm for 40 seconds, and 15 seconds before the end of the second spin coating step, 300 μL of ethyl acetate antisolvent was dripped on the rotating substrate, and then the substrate was annealed at a temperature of 100°C and a time of 10 minutes to obtain the final tin-containing perovskite film.

[0066] Step 4: Evaporate the electron transport layer C on the surface of the above Sn-Pb perovskite active layer 60 , the thickness of which is 25nm; and a vapor-deposited hole blocking layer BCP, the thickness of which is 6nm;

[0067] Step 5: Vapor-deposit a cathode electrode layer of Cu on the surface of the hole blocking layer to a thickness of 90 nm;

[0068] After the above steps are completed, a pure inorganic tin-lead perovskite solar cell with a 3-trifluoromethylpyridine-doped perovskite layer is obtained.

[0069] Example 6

[0070] Based on Glass / ITO / PEDOT:PSS / 3-trifluoromethylpyridine doped perovskite / C 60 Preparation of a pure inorganic tin-lead perovskite solar cell with a / BCP / Cu device structure, changing the amount of 3-trifluoromethylpyridine added to the perovskite precursor mixed solution in step 3 of Example 5. In this example, no 3-trifluoromethylpyridine was added, and the other operations were the same as in Example 5.

[0071] Example 7

[0072] Based on Glass / ITO / PEDOT:PSS / 3-trifluoromethylpyridine doped perovskite / C 60Preparation of a pure inorganic tin-lead perovskite solar cell with a Cu / BCP / Cu device structure, changing the amount of 3-trifluoromethylpyridine added to the perovskite precursor mixed solution in step 3 of Example 5 to 2.0%, and other operations were the same as Example 5.

[0073] Example 8

[0074] Based on Glass / ITO / PEDOT:PSS / 3-trifluoromethylpyridine doped perovskite / C 60 Preparation of a pure inorganic tin-lead perovskite solar cell with a Cu / BCP / Cu device structure, changing the amount of 3-trifluoromethylpyridine added to the perovskite precursor mixed solution in step 3 of Example 5 to 5.0%, and other operations were the same as Example 5.

[0075] Table 2 Comparison of parameters of pure inorganic tin-lead perovskite solar cells prepared in Examples 5-8

[0076]

[0077] It can be found from Table 2 that different 3-trifluoromethylpyridine doping amounts have different effects on the photoelectric conversion efficiency of the final device. Compared with Example 5, Example 7 and Example 8 respectively add 3.5 mol%, 2 mol%, and 5 mol% of 3-trifluoromethylpyridine to the pure inorganic tin-lead perovskite precursor mixed solution to obtain a perovskite precursor solution with a gradient doping amount. It can be found from Table 2 that in Example 5, when the doping amount of 3-trifluoromethylpyridine is 3.5 mol%, thanks to the effect of 3-trifluoromethylpyridine on Sn in the perovskite, the photoelectric conversion efficiency of the final device is different. 2+ Oxidation inhibition and film crystallization modulation reduce the defects on the surface and grain boundaries of tin-lead perovskite, improve the film quality, significantly reduce the energy loss caused by non-radiative recombination, and the device has the highest open circuit voltage (V oc ), short-circuit current (J sc ), fill factor (FF) and the final photoelectric conversion efficiency; at the same time, compared with Example 6, various parameters of Example 7 and Example 8 are improved to varying degrees, but the effects are not as good as Example 5. Therefore, based on the experimental results, it is determined that the additive used in Example 5 is the optimal doping amount.

Claims

1. A method for preparing a tin-containing perovskite solar cell doped with 3-trifluoromethylpyridine, characterized in that: The steps include: 1) Ultrasonic cleaning of the transparent conductive substrate, drying the transparent conductive substrate with a nitrogen stream before use, and then treating the surface of the transparent conductive substrate with a plasma cleaner or ozone; 2) depositing a hole transport layer HTL solution on the surface of the transparent conductive substrate treated in step 1), and performing annealing treatment to obtain an HTL film; 3) adding 3-trifluoromethylpyridine to a tin-containing perovskite precursor solution and stirring the mixture to obtain a 3-trifluoromethylpyridine-doped tin-containing perovskite precursor solution, depositing the solution on the surface of the HTL film, and annealing the resulting solution to obtain a tin-containing perovskite active layer; 4) subsequently depositing an electron transport layer and a hole blocking layer on the surface of the tin-containing perovskite active layer obtained in step 3); 5) depositing a top electrode on the surface of the thin film obtained in step 4), and finally obtaining a tin-containing perovskite solar cell based on 3-trifluoromethylpyridine-doped perovskite.

2. The method for preparing a tin-containing perovskite solar cell doped with 3-trifluoromethylpyridine according to claim 1, wherein: The transparent conductive substrate in step 1) is Glass / ITO or FTO, plastic flexible substrate / ITO or FTO, and the transparent conductive substrate is ultrasonically cleaned using distilled water, acetone, and isopropyl alcohol solvents in sequence.

3. The method for preparing a tin-containing perovskite solar cell doped with 3-trifluoromethylpyridine according to claim 1, wherein: The HTL solution in step 2) is a mixed material of one or more of PEDOT:PSS, PTAA, MeO-2PACz, and 4PACz.

4. The method for preparing a tin-containing perovskite solar cell doped with 3-trifluoromethylpyridine according to claim 3, characterized in that: The HTL solution is spin-coated on the surface-treated transparent conductive substrate, and then annealed to obtain a hole transport layer. The spin-coating speed is 5000-6000 rpm and the spin-coating time is 30-40 seconds. The annealing temperature is 90-110°C and the annealing time is 5-10 minutes.

5. The method for preparing a tin-containing perovskite solar cell doped with 3-trifluoromethylpyridine according to claim 1, wherein: The tin-containing perovskite precursor solution in step 3) is any organic-inorganic hybrid perovskite or inorganic perovskite containing metallic tin, and the thickness of the tin-containing perovskite active layer is 600-800 nm.

6. The method for preparing a tin-containing perovskite solar cell doped with 3-trifluoromethylpyridine according to claim 5, characterized in that: The tin-containing perovskite precursor solution described in step 3) is FA x MA 1-x Sn y Pb 1-y I3, 0 ≤ x ≤ 1, 0 < y ≤ 1 or CsSn x Pb 1-x I 2.7 Br 0.3 , 0 < x ≤ 1.

7. The method for preparing a tin-containing perovskite solar cell doped with 3-trifluoromethylpyridine according to claim 5, characterized in that: In step 3), the doping amount of 3-trifluoromethylpyridine is 1-5 mol% of the tin-containing perovskite precursor solution. 3-trifluoromethylpyridine is added to the tin-containing perovskite precursor solution and stirred for 0.5-1.5 hours. It is then filtered through a polytetrafluoroethylene membrane to obtain a 3-trifluoromethylpyridine-doped tin-containing perovskite precursor solution.

8. The method for preparing a tin-containing perovskite solar cell doped with 3-trifluoromethylpyridine according to claim 5, characterized in that: In step 3), a two-step spin coating deposition is performed, first at a speed of 500-1000 rpm for 5-10 seconds, and then at a speed of 4000-5000 rpm for 30-50 seconds. 10-20 seconds before the end of the second spin coating, 100-300 μL of ethyl acetate antisolvent is dripped onto the rotating substrate, and then the substrate is annealed to obtain a perovskite film at a temperature of 90-110°C for 5-20 minutes.

9. The method for preparing a tin-containing perovskite solar cell doped with 3-trifluoromethylpyridine according to claim 1, wherein: The electron transport layer in step 4) is PC 61 BM, PC 71 BM, C 60 、C 70 The hole blocking layer is BCP, and the top electrode in step 5) is a combination of one or more materials selected from Ag, Au, Cu, AZO, carbon materials, and conductive polymers.

10. A tin-containing perovskite solar cell doped with 3-trifluoromethylpyridine prepared by the preparation method according to any one of claims 1 to 9.

Images