A perovskite solar cell based on a double-layer modification strategy and its preparation method

Abstract

A perovskite solar cell based on a double-layer modification strategy and a preparation method thereof relate to the technical field of perovskite solar cells and solve the problem of limited performance improvement of existing perovskite solar cell devices. The present invention implements a simple and effective double-layer modification strategy, introducing highly conductive EGaIn NPs (LM NPs) with a core-shell structure into the SnO2 electron transport layer, reducing the defect density of the electron transport layer and enhancing the conductivity and electron extraction ability; and also introducing a small molecule material [bis(trifluoroacetoxy)iodide]pentafluorobenzene (FP) with a carbonyl ‑C=O and a hydrophobic functional group ‑CF3 into the perovskite layer, reducing the defect density of the perovskite layer, enhancing its hydrophobicity and crystal quality, and achieving stable and good carrier transport. Based on the synergistic effect of the above-mentioned double-layer modification, the perovskite solar cell successfully achieved a photoelectric conversion efficiency (PCE) of 23.15%.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite solar cells, and in particular to a perovskite solar cell based on a double-layer modification strategy and a preparation method thereof. Background Art

[0002] The power conversion efficiency of organic-inorganic hybrid perovskite solar cells has achieved significant breakthroughs over the past decade, rapidly increasing from 3.8% in 2009 to a certified efficiency of 26.1%, approaching its theoretical efficiency (31%). This rapid increase in the PCE of perovskite solar cells (PSCs) is primarily due to the superior properties of perovskite materials, such as high crystallinity, long electron-hole diffusion length, and wide absorption range, making them a research hotspot in the photovoltaic field. However, achieving the efficiency and stability of PSCs remains challenging.

[0003] Because solution-processed perovskite films typically exhibit a polycrystalline morphology and often contain uncoordinated ions, defect states inevitably arise on the surface and in the bulk of the perovskite film, leading to carrier recombination and limiting improvements in device efficiency and stability. Furthermore, the weak adhesion of the perovskite layer makes it soft and susceptible to corrosion from ambient oxygen and water, compromising device stability.

[0004] In order to improve device performance, researchers have proposed many methods and made a lot of attempts to further improve the PCE and stability of PSCs. SC ) is approaching its limit, forcing researchers to pay more attention to increasing the open circuit voltage (V OC ) or fill factor (FF), further improving PCE. It is reported that non-radiative trap recombination seriously affects the improvement of FF. In addition, uncoordinated ions in perovskite films act as centers for non-radiative recombination, leading to severe carrier recombination. In order to further improve the performance of PSCs, non-radiative recombination in the perovskite layer must be suppressed. In addition, the device performance of SnO2-based perovskite solar cells is seriously affected by the low intrinsic conductivity of SnO2 and the poor interface contact between SnO2 and perovskite films. To this end, many methods have been proposed, such as composition engineering, interface engineering, passivation engineering, packaging and device structure engineering. Among these methods, passivation engineering is widely used due to its simple process. However, most previous reports only focused on improving the quality of perovskite films through single-layer passivation, without considering improving the electron extraction ability of tin dioxide while passivating the defects of the perovskite layer. The improvement direction is relatively single and the performance improvement effect is limited. Summary of the Invention

[0005] In order to solve the problem of limited performance improvement of existing perovskite solar cell devices, the present invention proposes a perovskite solar cell based on a double-layer modification strategy and a preparation method thereof.

[0006] The technical solutions of the present invention are as follows:

[0007] A method for preparing a perovskite solar cell based on a double-layer modification strategy comprises the following steps:

[0008] S1, ultrasonically clean the FTO conductive substrate, dry it, and then treat it with UV ozone;

[0009] S2. Polymer preparation: BASF transparent acrylic resin 678 and epoxy resin water-based modifier M2070 was mixed, heated and stirred until the mixture became a dark golden colloidal solution, and then cooled to room temperature to obtain a polymer;

[0010] S3. Preparation of EGaIn NPs: EGaIn liquid metal and the polymer prepared in step S2 were mixed in deionized water and then ultrasonicated to obtain a gray EGaIn NPs suspension;

[0011] S4. Preparation of SnO2-LM precursor solution: SnO2 colloidal dispersion was mixed with deionized water and then sonicated to obtain SnO2 precursor solution; EGaIn NPs suspension was then mixed with SnO2 precursor solution, shaken and filtered to obtain SnO2-LM precursor solution;

[0012] S5, spin coating a SnO2-LM precursor solution on the FTO conductive substrate treated in step S1, and then annealing to obtain a SnO2-LM electron transport layer;

[0013] S6, Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 )3 (Perovskite) perovskite precursor solution preparation: PbI2, FAI, PbBr2, MABr are added to a mixed solvent of DMF and DMSO; CsI is dissolved in DMSO and then added to the mixed solvent to obtain a Perovskite perovskite precursor solution;

[0014] S7. After UV-ozone treatment of the SnO2-LM electron transport layer, the film was transferred to a nitrogen glove box and FP was dissolved in anhydrous ether as an antisolvent. The perovskite film was spin-coated in two steps, at 600 rpm for 6 seconds and 4000 rpm for 50 seconds. At the beginning of the second step, the antisolvent was added dropwise to the center of the film to extract the solvent, followed by annealing to obtain the perovskite-FP perovskite light absorption layer.

[0015] S8, dissolving Spiro OMeTAD in chlorobenzene to obtain a Spiro OMeTAD original solution; dissolving Li TFSI in acetonitrile to obtain a Li TFSI acetonitrile solution; adding the Li TFSI acetonitrile solution and the TBP solution to the Spiro OMeTAD original solution to obtain a Spiro OMeTAD hole transport layer solution;

[0016] S9. In a nitrogen glove box, spin-coat the Spiro-OMeTAD hole transport layer solution on the surface of the Perovskite-FP perovskite light absorption layer at a speed of 4000 rpm for 30 seconds to obtain a hole transport layer with a thickness of 200 nm.

[0017] S10. Vacuum evaporation is used to deposit a silver electrode on the hole transport layer to obtain a perovskite solar cell.

[0018] Preferably, the ultrasonic cleaning process in step S1 is: ultrasonic cleaning with detergent, deionized water, ethanol and acetone respectively.

[0019] Preferably, the BASF transparent acrylic resin in step S2 678 and epoxy resin water-based modifier The mass ratio of M2070 is 1:4;

[0020] The heating temperature is 170° C., and the stirring time is 2 to 6 hours.

[0021] Preferably, the mass ratio of the EGaIn liquid metal to the polymer in step S3 is 1:1.

[0022] Preferably, in step S4, the volume ratio of the SnO2 colloidal dispersion to deionized water is 1:3.

[0023] Preferably, the filtration in step S4 specifically uses a 0.1 μm aqueous needle filter.

[0024] Preferably, the SnO2-LM precursor solution in step S5 is 80-150 μL.

[0025] Preferably, the usage ratio of PbI2, FAI, PbBr2, MABr, CsI, DMF and DMSO in step S6 is 1.1 mmol: 1 mmol: 0.2 mmol: 0.2 mmol: 1.5 mmol: 800 μL: 200 μL.

[0026] Preferably, the amount of the anti-solvent in step S7 is 500 μL.

[0027] The molecular formula of the [bis(trifluoroacetyloxy)iodo]pentafluorobenzene (FP) is C 10 F 11 IO4, the structural formula is as follows:

[0028]

[0029] The present invention provides a perovskite solar cell based on a double-layer modification strategy, which is prepared using the above-mentioned preparation method. The perovskite solar cell comprises an FTO conductive substrate, an electron transport layer, a perovskite light absorption layer, a hole transport layer, and a silver electrode.

[0030] Compared with the prior art, the present invention has the following specific beneficial effects:

[0031] The present invention realizes a simple and effective double-layer modification strategy, which introduces highly conductive EGaInNPs (LMNPs) with a core-shell structure into the SnO2 electron transport layer, reduces the defect density of the electron transport layer, and enhances the conductivity and electron extraction ability; and also introduces a small molecule material FP with a carbonyl group -C=O and a hydrophobic functional group -CF3 into the perovskite layer, passivating the uncoordinated Pb in the perovskite film. 2+ , reducing the defect density of the perovskite layer, enhancing its hydrophobicity and crystal quality, thereby enhancing the humidity stability of the device and achieving stable and good carrier transport. Based on the synergistic effect of the above double-layer modification, the perovskite solar cell successfully achieved a photoelectric conversion efficiency (PCE) of 23.15%. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the structure of a perovskite solar cell based on a double-layer modification strategy in Example 1;

[0033] Figure 2 The IV test results of the electron transport layer films of Example 1 and Comparative Example 1 under dark conditions for FTO / SnO2 / Ag and FTO / SnO2-LM / Ag devices are shown;

[0034] Figure 3 SCLC curves of SnO2-LM and SnO2 obtained under dark conditions for the electron transport layer films of Example 1 and Comparative Example 1;

[0035] Figure 4 SCLC curves of the Perovskite-FP perovskite light absorbing layer and the Perovskite perovskite light absorbing layer measured under dark conditions for the hole-only device having a structure of FTO / PEDOT:PSS / (Perovskite-FP or Perovskite) / Spiro-OMeTAD / Ag prepared according to Example 2 of the present invention and Comparative Example 1;

[0036] Figure 5 For the electron transport layer and perovskite light absorption layer films according to Example 1 and Comparative Example 1 of the present invention, the SCLC curves of SnO2-LM / Perovskite-FP and SnO2 / Perovskite were measured under dark conditions by preparing an electronic device with an FTO / (SnO2-LM or SnO2) / (Perovskite-FP or Perovskite) / PCBM / Ag structure;

[0037] Figure 6 Steady-state PL spectra of the perovskite films in Example 2 and Comparative Example 1;

[0038] Figure 7 Steady-state PL spectra of SnO2-LM / Perovskite-FP and SnO2 / Perovskite films in Example 1 and Comparative Example 1;

[0039] Figure 8 is the water contact angle of the original Perovskite, Perovskite-FP and SnO2-LM / Perovskite-FP films in Comparative Example 1, Example 2 and Example 1;

[0040] Figure 9 The perovskite solar cells in Example 1 and Comparative Example 1 were subjected to standard sunlight (AM1.5, 100 mW / cm 2 ) Current density voltage characteristic curve under irradiation;

[0041] Figure 10 Stability curves of the perovskite solar cells prepared in Example 1 and Comparative Example 1 after being placed in an environment with a humidity of about 50% for 1600 hours. DETAILED DESCRIPTION

[0042] In order to make the technical solution of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the specification of the present invention. It should be noted that the following embodiments are only used to better understand the technical solution of the present invention and should not be understood as limiting the present invention.

[0043] Example 1.

[0044] (1) The FTO conductive substrate was ultrasonically cleaned with detergent, deionized water, ethanol, and acetone for 20 min, respectively, and then dried in an oven at 60°C;

[0045] (2) treating the cleaned and dried FTO conductive substrate with UV ozone for 30 min;

[0046] (3) Preparation of polymer: BASF transparent acrylic resin 678 and epoxy resin water-based modifier M2070 was mixed in a three-necked flask fixed in a magnetic heating stirrer at a ratio of 1:4, heated and stirred in an oil bath at 170°C for 2 to 6 hours until the mixture became a dark golden colloidal solution. After cooling to room temperature (25°C), the polymer was obtained, which was placed in a transparent glass vial, sealed with a sealing film, and stored at room temperature.

[0047] (4) Preparation of EGaIn NPs: EGaIn liquid metal (0.25 g) and the polymer (0.25 g) prepared in step (3) were mixed in deionized water (4.9 g), and then sonicated in an ultrasonic machine for 4 to 8 h to obtain a gray EGaIn NPs suspension;

[0048] (5) Preparation of SnO2 precursor solution: SnO2 colloidal dispersion was mixed with deionized water at a volume ratio of 1:3, and then ultrasonicated in an ultrasonic machine for 4-8 h to obtain a SnO2 precursor solution;

[0049] (6) Preparation of SnO2-LM precursor solution: The EGaIn NPs prepared in step (4) were mixed with the ultrasonically treated SnO2 aqueous solution in a certain proportion, shaken, and filtered through a 0.1 μm aqueous needle filter to obtain a SnO2-LM precursor solution;

[0050] (7) adding 80-150 μL SnO2-LM precursor solution onto the FTO conductive substrate after UV ozone treatment in step (2), spin coating at a speed of 5000 rpm for 30 seconds, and annealing at 150°C for 30 minutes to obtain a SnO2-LM electron transport layer;

[0051] (8)Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17)3 (Perovskite) perovskite precursor solution preparation: PbI2 (1.1 mmol), FAI (1 mmol), PbBr2 (0.2 mmol), MABr (0.2 mmol) were added to a mixed solvent of DMF (800 μL) and DMSO (200 μL); at the same time, 1.5 mmol of CsI was dissolved in 900 μL of DMSO; then, CsI solution was added to the above solution at a volume ratio of 5:95 (CsI: mixture) to obtain the final Perovskite perovskite precursor solution;

[0052] (9) After the SnO2-LM electron transport layer was treated with UV-ozone for 20 min, it was transferred to a nitrogen glove box and FP was dissolved in anhydrous ether as an antisolvent. The spin coating procedure of the perovskite film was two steps, with two consecutive spin coating procedures at 600 rpm and 4000 rpm for 6 s and 50 s respectively. At the beginning of the second step, 500 μL of antisolvent was quickly dripped into the center of the film to extract the solvent. After the spin coating procedure, the film was annealed at 150 °C for 10 min to obtain the Perovskite-FP perovskite light absorption layer.

[0053] (10) Dissolve 72.3 mg of Spiro OMeTAD in 1 mL of chlorobenzene to obtain a Spiro OMeTAD stock solution; dissolve 520 mg of Li TFSI in 1 mL of acetonitrile to obtain a Li TFSI acetonitrile solution; add 17.5 μL of Li TFSI acetonitrile solution and 28.8 μL of TBP solution to the Spiro OMeTAD stock solution to obtain a Spiro OMeTAD hole transport layer solution;

[0054] (11) In a nitrogen glove box, the Spiro-OMeTAD hole transport layer solution was spin-coated at 4000 rpm for 30 s on the surface of the Perovskite-FP perovskite light absorption layer after cooling to room temperature in step (9) without annealing to obtain a hole transport layer with a thickness of 200 nm;

[0055] (12) On the hole transport layer, a 100 nm thick silver electrode was deposited by vacuum evaporation to obtain a perovskite solar cell.

[0056] Example 2.

[0057] (1) The FTO conductive substrate was ultrasonically cleaned with detergent, deionized water, ethanol, and acetone for 20 min, respectively, and then dried in an oven at 60°C;

[0058] (2) treating the cleaned and dried FTO conductive substrate with UV ozone for 30 min;

[0059] (3) Preparation of SnO2 precursor solution: SnO2 colloidal dispersion was mixed with deionized water at a volume ratio of 1:3, and then ultrasonicated in an ultrasonic machine for 4 to 8 hours to obtain a SnO2 precursor solution;

[0060] (4) adding 80-150 μL of SnO2 precursor solution onto the FTO conductive substrate treated with UV ozone in step (2), spin coating at a speed of 5000 rpm for 30 seconds, and annealing at 150°C for 30 minutes to obtain a SnO2 electron transport layer;

[0061] (5)Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 )3 (Perovskite) perovskite precursor solution preparation: PbI2 (1.1 mmol), FAI (1 mmol), PbBr2 (0.2 mmol), MABr (0.2 mmol) were added to a mixed solvent of DMF (800 μL) and DMSO (200 μL); at the same time, 1.5 mmol of CsI was dissolved in 900 μL of DMSO; then, CsI solution was added to the above solution at a volume ratio of 5:95 (CsI: mixture) to obtain the final Perovskite perovskite precursor solution;

[0062] (6) After the SnO2 electron transport layer was treated with UV-ozone for 20 min, it was transferred to a nitrogen glove box and FP was dissolved in anhydrous ether as an antisolvent. The spin coating procedure of the perovskite film was two steps, with two consecutive spin coating procedures at 600 rpm and 4000 rpm for 6 seconds and 50 seconds respectively. At the beginning of the second step, 500 μL of antisolvent was quickly dripped into the center of the film to extract the solvent. After the spin coating procedure was completed, the film was annealed at 150 ° C for 10 min to finally obtain the Perovskite-FP perovskite light absorption layer.

[0063] (7) Dissolve 72.3 mg of Spiro OMeTAD powder in 1 mL of chlorobenzene to obtain a Spiro OMeTAD stock solution; dissolve 520 mg of Li TFSI in 1 mL of acetonitrile to obtain a Li TFSI acetonitrile solution; add 17.5 μL of Li TFSI acetonitrile solution and 28.8 μL of TBP solution to the Spiro OMeTAD stock solution to obtain a Spiro OMeTAD hole transport layer solution;

[0064] (8) In a nitrogen glove box, the Spiro-OMeTAD hole transport layer solution was spin-coated at 4000 rpm for 30 s on the surface of the Perovskite-FP perovskite light absorption layer after cooling to room temperature in step (6) without annealing to obtain a hole transport layer with a thickness of 200 nm;

[0065] (9) On the hole transport layer, a 100 nm thick silver electrode was deposited by vacuum evaporation to obtain a perovskite solar cell.

[0066] Comparative Example 1.

[0067] (1) The FTO conductive substrate was ultrasonically cleaned with detergent, deionized water, ethanol, and acetone for 20 min, respectively, and then dried in an oven at 60°C;

[0068] (2) treating the cleaned and dried FTO conductive substrate with UV ozone for 30 min;

[0069] (3) Preparation of SnO2 precursor solution: SnO2 colloidal dispersion was mixed with deionized water at a volume ratio of 1:3, and then ultrasonicated in an ultrasonic machine for 4 to 8 hours to obtain a SnO2 precursor solution;

[0070] (4) Spin coating 80-150 μL of SnO2 precursor solution on the FTO conductive substrate after UV ozone treatment in step (2) at a speed of 5000 rpm for 30 seconds, and annealing at 150°C for 30 minutes to obtain a SnO2 electron transport layer;

[0071] (5)Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 )3 (Perovskite) perovskite precursor solution preparation: PbI2 (1.1 mmol), FAI (1 mmol), PbBr2 (0.2 mmol), MABr (0.2 mmol) were added to a mixed solvent of DMF (800 μL) and DMSO (200 μL); at the same time, 1.5 mmol of CsI was dissolved in 900 μL of DMSO; then, CsI solution was added to the above solution at a volume ratio of 5:95 (CsI: mixture) to obtain the final Perovskite perovskite precursor solution;

[0072] (6) After the SnO2 electron transport layer was treated with UV ozone for 20 minutes, it was transferred to a nitrogen glove box; the spin coating procedure of the perovskite film was two steps, with two consecutive spin coating procedures at 600 rpm and 4000 rpm for 6 seconds and 50 seconds respectively; at the beginning of the second step, 500 μL of anhydrous ether was quickly dripped into the center of the film to extract the solvent; after the spin coating procedure, it was annealed at 150 ° C for 10 minutes to finally obtain the perovskite light absorption layer;

[0073] (7) Dissolve 72.3 mg of Spiro OMeTAD powder in 1 mL of chlorobenzene to obtain a Spiro OMeTAD stock solution; dissolve 520 mg of Li TFSI in 1 mL of acetonitrile to obtain a Li TFSI acetonitrile solution; add 17.5 μL of Li TFSI acetonitrile solution and 28.8 μL of TBP solution to the Spiro OMeTAD stock solution to obtain a Spiro OMeTAD hole transport layer solution;

[0074] (8) In a nitrogen glove box, the Spiro-OMeTAD hole transport layer solution was spin-coated at 4000 rpm for 30 seconds on the surface of the perovskite light absorption layer after cooling to room temperature in step (6) without annealing to obtain a hole transport layer with a thickness of 200 nm;

[0075] (9) On the hole transport layer, a 100 nm thick silver electrode was deposited by vacuum evaporation to obtain a perovskite solar cell.

[0076] Performance testing:

[0077] like Figure 1 As shown, the structure of the perovskite solar cell based on the double-layer modification strategy prepared in Example 1 is FTO / SnO2-LM / Perovskite-FP / Spiro-OMeTAD / Ag.

[0078] from Figure 2 It can be seen that the electrical conductivity of SnO2-LM is higher than that of SnO2.

[0079] Figure 3 The SCLC curves of SnO2-LM and SnO2 obtained in dark conditions for the electron transport layer films of Example 1 and Comparative Example 1 are shown. It can be seen that the defect density in the ETL transport layer is successfully reduced after the introduction of LM NPs.

[0080] Figure 4For the hole-only devices of the FTO / PEDOT:PSS / (Perovskite-FP or Perovskite) / Spiro-OMeTAD / Ag structure prepared in Example 2 and Comparative Example 1, the SCLC curves of the Perovskite-FP perovskite light absorbing layer and the Perovskite perovskite light absorbing layer were measured under dark conditions. Figure 4 It can be seen that the device prepared in Example 2 has a lower trap filling limit voltage, indicating that the material passivation of the PSCs is successful and the PSCs are successfully prepared.

[0081] from Figure 5 It can be seen that the device prepared in Example 1 has a lower trap filling limit voltage, indicating that the double-layer modification strategy is successful.

[0082] Figure 6 Figure 2 is the PL spectra of the perovskite light absorbing layer in Comparative Example 1 and Example 2. It can be seen that the PL intensity of the perovskite light absorbing layer in Example 2 is significantly increased compared with that in Comparative Example 1, indicating that the introduction of FP into the perovskite precursor effectively passivates the defects in the perovskite film, inhibits non-radiative recombination, and reduces the defect density.

[0083] Figure 7 PL spectra of the electron transport layer / perovskite light absorbing layer in Comparative Example 1 and Example 1. It can be seen that the PL intensity of Example 1 is significantly lower than that of Comparative Example 1, indicating that the double-layer modification strategy enhances charge extraction.

[0084] Figure 8 The water contact angles of the original Perovskite, Perovskite-FP and SnO2-LM / Perovskite-FP films prepared in Comparative Example 1, Example 2 and Example 1. Figure 8 It can be seen that FP modification can increase the water contact angle of the perovskite film, improve the hydrophobicity of the perovskite film, and help enhance the humidity stability of the perovskite film.

[0085] like Figure 9 As shown in Figure 1, the PSCs prepared in Comparative Example 1 achieved a PCE of 21.13% in the reverse scan (RS) direction, an open circuit voltage (Voc) of 1.18 V, and a short circuit current density (Jsc) of 23.79 mA cm -2 , the fill factor (FF) was 75.00%. A hysteresis index (HI = (PCE reverse - PCE forward) / PCE reverse) of 5.48% was observed, as the PSCs exhibited a PCE of 19.97% in the forward scan (FS) direction. The double-layer modification strategy successfully reduced the V OC Increased to 1.21V, J SC Increased to 23.85 mA cm-2 , the FF is improved to 79.67%, resulting in a PCE of 23.15% in the RS direction. In addition, the optimized PSCs also show a PCE of 22.40% in the FS direction, showing a smaller hysteresis (HI = 3.23%).

[0086] Table 1 shows the performance parameters of the best devices based on Comparative Example 1 and Example 1 in the FS and RS directions. Figure 9 As can be seen from Table 1, the introduction of LM NPs and FP in Example 1 improves the J SC , FF and V OC .J SC , FF and V OC The enhancement is mainly attributed to the improved conductivity of the SnO2 electron transport layer, the improved film quality of the perovskite light absorption layer, the reduced non-radiative recombination and defect density, and the improved charge carrier separation and extraction.

[0087] Table 1.

[0088]

[0089] from Figure 10 It can be seen that when the PSCs prepared in Example 1 and Comparative Example 1 of the present invention were subjected to an ambient humidity of about 50%, after 1600 hours of testing, the PCE of the PSCs prepared in Comparative Example 1 dropped to 71%, while the PCE of the PSCs prepared in Example 1 still maintained 80% of the initial value, showing good humidity stability.

[0090] The specific embodiments described above are merely detailed descriptions of the embodiments of the present invention. However, these embodiments are only a small part of the present invention, not all of the embodiments. It should be noted that those skilled in the art may make various changes, modifications, substitutions, and variations to these embodiments without departing from the principles and spirit of the present invention, and these are also within the scope of protection of the present invention. The scope of protection of the patent for this invention shall be based on the appended claims.

Claims

1. A method for preparing a perovskite solar cell based on a double-layer modification strategy, characterized in that: The steps include: S1, ultrasonically clean the FTO conductive substrate, dry it, and then treat it with UV ozone; S2. Polymer preparation: BASF transparent acrylic resin 678 and epoxy resin water-based modifier M2070 was mixed, heated and stirred until the mixture became a dark golden colloidal solution, and then cooled to room temperature to obtain a polymer; S3. Preparation of EGaIn NPs: EGaIn liquid metal and the polymer prepared in step S2 were mixed in deionized water and then ultrasonicated to obtain a gray EGaIn NPs suspension; S4. Preparation of SnO2-LM precursor solution: SnO2 colloidal dispersion was mixed with deionized water and then sonicated to obtain SnO2 precursor solution; EGaIn NPs suspension was then mixed with SnO2 precursor solution, shaken and filtered to obtain SnO2-LM precursor solution; S5, spin coating a SnO2-LM precursor solution on the FTO conductive substrate treated in step S1, and then annealing to obtain a SnO2-LM electron transport layer; S6, Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 )3 Preparation of perovskite precursor solution: PbI2, FAI, PbBr2, and MABr are added to a mixed solvent of DMF and DMSO; CsI is dissolved in DMSO and then added to the mixed solvent to obtain a perovskite precursor solution; S7. After UV-ozone treatment of the SnO2-LM electron transport layer, the film was transferred to a nitrogen glove box and [bis(trifluoroacetoxy)iodo]pentafluorobenzene was dissolved in anhydrous ether as an antisolvent. The perovskite film was spin-coated in two steps, at 600 rpm and 4000 rpm for 6 seconds and 50 seconds, respectively. At the beginning of the second step, the antisolvent was added dropwise to the center of the film to extract the solvent, followed by annealing to obtain the Perovskite-FP perovskite light absorption layer. S8, dissolving Spiro OMeTAD in chlorobenzene to obtain a Spiro OMeTAD original solution; dissolving Li TFSI in acetonitrile to obtain an acetonitrile solution of Li TFSI; Adding Li TFSI in acetonitrile and TBP solution to the original solution of Spiro OMeTAD to obtain a Spiro OMeTAD hole transport layer solution; S9. In a nitrogen glove box, spin-coat the Spiro-OMeTAD hole transport layer solution on the surface of the Perovskite-FP perovskite light absorption layer at a speed of 4000 rpm for 30 seconds to obtain a hole transport layer with a thickness of 200 nm. S10. Vacuum evaporation is used to deposit a silver electrode on the hole transport layer to obtain a perovskite solar cell.

2. The method for preparing a perovskite solar cell based on a double-layer modification strategy according to claim 1, characterized in that: The ultrasonic cleaning process in step S1 is: ultrasonic cleaning with detergent, deionized water, ethanol and acetone respectively.

3. The method for preparing a perovskite solar cell based on a double-layer modification strategy according to claim 1, characterized in that: BASF transparent acrylic resin in step S2 678 and epoxy resin water-based modifier The mass ratio of M2070 is 1:4; The heating temperature is 170° C., and the stirring time is 2 to 6 hours.

4. The method for preparing a perovskite solar cell based on a double-layer modification strategy according to claim 1, characterized in that: The mass ratio of the EGaIn liquid metal to the polymer in step S3 is 1:

1.

5. The method for preparing a perovskite solar cell based on a double-layer modification strategy according to claim 1, characterized in that: The volume ratio of the SnO2 colloidal dispersion to deionized water in step S4 is 1:

3.

6. The method for preparing a perovskite solar cell based on a double-layer modification strategy according to claim 1, characterized in that: The filtration in step S4 specifically uses a 0.1 μm aqueous needle filter.

7. The method for preparing a perovskite solar cell based on a double-layer modification strategy according to claim 1, characterized in that: The SnO2-LM precursor solution in step S5 is 80 to 150 μL.

8. The method for preparing a perovskite solar cell based on a double-layer modification strategy according to claim 1, characterized in that: The usage ratio of PbI2, FAI, PbBr2, MABr, CsI, DMF and DMSO in step S6 is 1.1 mmol: 1 mmol: 0.2 mmol: 0.2 mmol: 1.5 mmol: 800 μL: 200 μL.

9. The method for preparing a perovskite solar cell based on a double-layer modification strategy according to claim 1, characterized in that: The amount of the anti-solvent used in step S7 is 500 μL.

10. A perovskite solar cell based on a double-layer modification strategy, characterized in that: The method is described in any one of claims 1 to 9.

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