A surfactant-assisted synthesis of perovskite film and its preparation and assembly into solar cells

Abstract

The present invention belongs to the technical field of perovskite thin films, and relates to a surfactant-assisted synthesis of perovskite thin films and a solar cell prepared and assembled therefrom. In the present invention, an aqueous solution of tin dioxide quantum dots is coated on a substrate and then sintered; the obtained tin dioxide electron layer is soaked in an aqueous solution of titanium tetrachloride and then calcined; a solution of lead bromide in N,N-dimethylformamide is coated on the obtained tin dioxide-titanium oxychloride composite electron transport layer and then annealed; an aqueous solution of cesium bromide containing a surfactant is coated on the obtained lead bromide thin film and then annealed; a conductive paste is coated on the obtained CsPbBr3 perovskite thin film and then heat-treated to obtain a surfactant-assisted synthesis of perovskite thin film. The present invention improves problems such as poor film quality and serious charge recombination existing in CsPbBr3 all-inorganic solar cells through a surfactant, thereby improving the performance of the battery.

Description

Technical Field

[0001] The invention relates to the technical field of perovskite thin films, and in particular to a surfactant-assisted synthesis of a perovskite thin film and a solar cell prepared and assembled therefrom. Background Art

[0002] At present, the photoelectric conversion efficiency of organic-inorganic hybrid perovskite solar cells has reached 25.7% in just ten years. Perovskite may replace crystalline silicon and become the "new favorite" of solar cells. However, there are still many problems. For example, the organic components in organic-inorganic hybrid perovskite solar cells are not only expensive, but also have poor stability, which seriously affects its commercialization process. To solve these problems, researchers have prepared all-inorganic perovskite solar cells with superior performance and good stability by replacing organic ions with inorganic cesium ions. Among them, the all-bromine structure CsPbBr 3 It is the best among all-inorganic perovskites. It has excellent tolerance to long-term erosion by air, humidity, and continuous light, and is considered to be one of the most promising high-stability light-absorbing materials for perovskite solar cells.

[0003] However, the existing multi-step method for preparing CsPbBr 3 Perovskite films are prone to various byproducts due to the inability to accurately control the ratio of precursor raw materials, which can cause defect states, hinder the migration of charges, and induce radiative recombination and non-radiative recombination of carriers inside the device. 3 Perovskite not only has a cumbersome preparation process, which increases the preparation cost, but the required organic solvent is also environmentally unfriendly, which seriously limits the application of CsPbBr 3 The development of perovskite solar cells. Recently, a study proposed that the cesium bromide precursor solution can be prepared by replacing the methanol solvent with a green and non-toxic aqueous solution, which can accurately control the ratio of the precursor raw materials and prepare high-quality CsPbBr by a simple two-step method. 3 Perovskite film. However, due to the surface tension of the aqueous solution, the cesium bromide precursor aqueous solution spreads unevenly on the surface of the lead bromide film, and the local crystallization rate is too fast, which seriously affects the density of the film; on the other hand, due to the soft lattice characteristics of the perovskite film, there are a large number of defect states inside the film. Related studies have shown that the use of organic matter containing O, N, S, and P as additives can adjust the crystallization rate of perovskite and passivate defects, which is beneficial to the preparation of high-quality perovskite films. However, conventional organic matter is not easily soluble in aqueous solution, which limits its use in the two-step aqueous solution method for the preparation of CsPbBr 3 Applications in perovskite thin films.

[0004] Based on the above problems, a new water-soluble additive was developed to reduce the surface tension of the aqueous solution and make the cesium bromide solution spread more evenly, while passivating the film defects and preparing uniform and dense high-quality CsPbBr 3 Perovskite film, and at the same time regulating the band structure of the perovskite film to match it with the charge transport layer, has important theoretical significance and practical value for improving the efficiency and stability of the perovskite solar cells assembled therein. Summary of the invention

[0005] The purpose of the present invention is to make up for the deficiencies of the prior art and provide a surfactant-assisted synthesis of a perovskite film and a solar cell prepared and assembled therefrom.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for synthesizing a perovskite film assisted by a surfactant, comprising the following steps:

[0008] (1) coating a tin dioxide quantum dot aqueous solution on a substrate and then sintering it to obtain a tin dioxide electronic layer;

[0009] (2) soaking the obtained tin dioxide electron layer in a titanium tetrachloride aqueous solution and then calcining it to obtain a tin dioxide-chlorine-containing titanium oxide composite electron transport layer;

[0010] (3) coating an N,N-dimethylformamide solution of lead bromide on the obtained tin dioxide-chlorine-containing titanium oxide composite electron transport layer and then annealing to obtain a lead bromide thin film;

[0011] (4) coating the obtained lead bromide film with a cesium bromide aqueous solution containing a surfactant and then annealing the film to obtain CsPbBr 3 Perovskite thin films;

[0012] (5) Apply the conductive paste on the obtained CsPbBr 3 The perovskite film is then subjected to a heat treatment to obtain a surfactant-assisted synthesis of the perovskite film.

[0013] Preferably, the concentration of the tin dioxide quantum dot aqueous solution in step (1) is 0.1 to 1 mol / L;

[0014] The sintering temperature is 200-250° C. and the sintering time is 1-2 hours.

[0015] Preferably, the concentration of the titanium tetrachloride aqueous solution in step (2) is 0.03 to 0.1 mol / L;

[0016] The soaking temperature is 70-80° C. and the soaking time is 30-50 minutes.

[0017] Preferably, the calcination temperature in step (2) is 160-220° C. and the calcination time is 30-60 min.

[0018] Preferably, the concentration of the lead bromide N,N-dimethylformamide solution in step (3) is 0.8 to 1.2 mol / L;

[0019] The coating environment temperature is 60-110°C;

[0020] The annealing temperature is 90-110° C. and the annealing time is 30-60 min.

[0021] Preferably, the concentration of cesium bromide in the cesium bromide aqueous solution containing a surfactant in step (4) is 0.8 to 1.5 mol / L, and the molar ratio of the surfactant to cesium bromide is 0.1 to 1:100;

[0022] The surfactant comprises one or more of sulfonate anionic surfactants, sulfate anionic surfactants, fatty acid anionic surfactants, succinate anionic surfactants, ammonium salt cationic surfactants, quaternary ammonium salt cationic surfactants, amino acid zwitterionic surfactants, imidazoline zwitterionic surfactants, lecithin zwitterionic surfactants, betaine zwitterionic surfactants and nonionic surfactants;

[0023] The annealing temperature is 200-250° C. and the annealing time is 30-60 min.

[0024] Preferably, the temperature of the heating treatment in step (5) is 90 to 130° C. and the time is 30 to 60 minutes.

[0025] The invention also provides surfactant-assisted synthesis of perovskite film obtained by the method.

[0026] The present invention also provides a solar cell assembled by synthesizing a perovskite film assisted by the surfactant.

[0027] 1. The present invention prepares CsPbBr by a two-step aqueous solution method 3 The perovskite film can accurately control the ratio of precursor raw materials. Compared with the conventional multi-step method, the preparation process is streamlined, the operation is cheap, and the morphology and thickness of the perovskite film can be effectively controlled, the generation of defect states can be inhibited, and the film quality can be improved. The present invention is green and environmentally friendly, and water is used instead of methanol solvent to participate in the CsPbBr 3 The preparation of perovskite films is more in line with the concept of sustainable development.

[0028] 2. The present invention makes full use of the effect of surfactants on reducing the surface tension of aqueous solutions to effectively reduce the destructive effect of aqueous solutions on the film. At the same time, the surfactants in the present invention have lone pairs of electrons, which can combine with free lead ions, significantly passivate the defects inside and on the surface of the film, reduce the path of non-radiative recombination of carriers, and largely inhibit the charge recombination inside and on the surface of the perovskite film, thereby greatly improving the photoelectric conversion efficiency of the battery.

[0029] 3. The present invention improves CsPbBr by using surfactant 3 The poor film quality and serious charge recombination problems existing in all-inorganic solar cells are solved by this method to improve the performance of the battery. Compared with other additives, the material selection is more diverse and is ubiquitous in daily life. A small amount of detergent or soapy water can also significantly improve the quality of the film. 3 The efficiency of perovskite solar cells can reach more than 10%, and after operating for 30 days in a natural environment with a high relative humidity of 85%, the photoelectric conversion efficiency can still remain above 95% of the initial value. This work has been proven to be simple and feasible many times, and has great theoretical value and guiding significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the SEM of the perovskite film obtained in Example 1;

[0031] Figure 2 is the SEM of the perovskite film obtained in the comparative example;

[0032] Figure 3 JV curves of perovskite solar cells of the embodiment and the comparative example;

[0033] Figure 4 This is a stability diagram of the perovskite solar cells of Example 3 and the comparative example operating for 30 days under natural environment conditions with a high relative humidity of 85%. DETAILED DESCRIPTION

[0034] The present invention provides a method for synthesizing a perovskite film assisted by a surfactant, comprising the following steps:

[0035] (1) coating a tin dioxide quantum dot aqueous solution on a substrate and then sintering it to obtain a tin dioxide electronic layer;

[0036] (2) soaking the obtained tin dioxide electron layer in a titanium tetrachloride aqueous solution and then calcining it to obtain a tin dioxide-chlorine-containing titanium oxide composite electron transport layer;

[0037] (3) coating an N,N-dimethylformamide solution of lead bromide on the obtained tin dioxide-chlorine-containing titanium oxide composite electron transport layer and then annealing to obtain a lead bromide thin film;

[0038] (4) coating the obtained lead bromide film with a cesium bromide aqueous solution containing a surfactant and then annealing the film to obtain CsPbBr 3 Perovskite thin films;

[0039] (5) Apply the conductive paste on the obtained CsPbBr 3 The perovskite film is then subjected to a heat treatment to obtain a surfactant-assisted synthesis of the perovskite film.

[0040] In the present invention, the concentration of the tin dioxide quantum dot aqueous solution in step (1) is 0.1 to 1 mol / L, preferably 0.2 to 0.8 mol / L, and more preferably 0.4 to 0.6 mol / L;

[0041] The sintering temperature is 200-250°C, preferably 210-240°C, more preferably 220-230°C; the sintering time is 1-2h, preferably 1.2-1.8h, more preferably 1.4-1.6h;

[0042] The substrate is preferably FTO glass.

[0043] In the present invention, the concentration of the titanium tetrachloride aqueous solution in step (2) is 0.03 to 0.10 mol / L, preferably 0.035 to 0.08 mol / L, and more preferably 0.4 to 0.6 mol / L;

[0044] The soaking temperature is 70-80° C., preferably 74-77° C.; the soaking time is 30-50 min, preferably 35-45 min, and more preferably 40-42 min.

[0045] In the present invention, the calcination temperature in step (2) is 160-220° C., preferably 180-200° C., and the calcination time is 30-60 min, preferably 40-50 min.

[0046] In the present invention, in the step (2), the product obtained by immersion is preferably ultrasonically cleaned before calcination.

[0047] In the present invention, the concentration of the lead bromide N,N-dimethylformamide solution in step (3) is 0.8 to 1.2 mol / L, preferably 0.9 to 1 mol / L;

[0048] The coating environment temperature is 60-110°C, preferably 70-100°C, and more preferably 80-90°C;

[0049] The annealing temperature is 90-110° C., preferably 95-105° C., and more preferably 98-100° C.; the annealing time is 30-60 min, and preferably 40-50 min.

[0050] In the present invention, the concentration of cesium bromide in the cesium bromide aqueous solution containing a surfactant in step (4) is 0.8 to 1.5 mol / L, preferably 0.85 to 1.3 mol / L, and more preferably 0.9 to 1.1 mol / L; the molar ratio of the surfactant to cesium bromide is 0.1 to 1:100, preferably 0.15 to 0.8:100, and more preferably 0.2 to 0.6:100;

[0051] The surfactant comprises one or more of sulfonate anionic surfactants, sulfate anionic surfactants, fatty acid anionic surfactants, succinate anionic surfactants, ammonium salt cationic surfactants, quaternary ammonium salt cationic surfactants, amino acid zwitterionic surfactants, imidazoline zwitterionic surfactants, lecithin zwitterionic surfactants, betaine zwitterionic surfactants and nonionic surfactants;

[0052] Wherein, the sulfonate type anionic surfactant comprises one or more of sodium dodecylbenzene sulfonate, dodecylbenzene sulfonic acid and sodium 1-butane sulfonate;

[0053] The sulfate-type anionic surfactant includes one or more of ammonium dodecyl sulfate, sodium dodecyl sulfate and sodium octyl sulfate;

[0054] The fatty acid type anionic surfactant comprises one or more of potassium oleate, stearic acid, sodium stearate and magnesium stearate;

[0055] The succinate type anionic surfactant comprises one or more of diisobutyl sodium sulfosuccinate and dihexyl sodium sulfosuccinate;

[0056] The ammonium salt type cationic surfactant includes one or more of polythiazolium chloride, stearamidopropyl dimethyl lactate and N-oleoylsarcosine-octadecylamine salt;

[0057] The quaternary ammonium salt type cationic surfactant includes one or more of tetramethylammonium fluoride, tetrabutylammonium chloride and dodecyltrimethylammonium chloride;

[0058] The amino acid type zwitterionic surfactant comprises one or more of sodium N-hydroxymethylglycinate and disodium tallow iminodipropionate;

[0059] The imidazoline type zwitterionic surfactant comprises one or more of imidazoline and 1-butyl-2-methylimidazole;

[0060] The lecithin-type zwitterionic surfactant comprises lecithin;

[0061] The betaine-type zwitterionic surfactant includes one or more of lauryl betaine, citrate betaine and lauryl amide propyl betaine;

[0062] The nonionic surfactant comprises one or more of alkyl glucoside, fatty acid glyceride, fatty acid sorbitan and polysorbate;

[0063] The annealing temperature is 200-250° C., preferably 210-240° C., and more preferably 220-230° C.; the annealing time is 30-60 min, and preferably 40-50 min.

[0064] In the present invention, the coating in step (1), step (3) and step (4) is independently spin-coated, and the speed of the spin-coating is independently preferably 1800 to 2500 r / min, more preferably 2000 to 2300 r / min, and even more preferably 2100 to 2200 r / min;

[0065] In the present invention, the temperature of the heating treatment in step (5) is 90-130° C., preferably 100-120° C., and more preferably 110° C.; the time is 30-60 min, and preferably 40-50 min.

[0066] The coating in step (5) is by scraping, and the thickness of the obtained back electrode is preferably 15 to 30 μm, and more preferably 20 to 25 μm; the conductive paste is a carbon paste purchased from Shanghai Maxwell Chemical New Material Technology Co., Ltd., and is prepared by dissolving a mixture of graphite and carbon black in an acrylic resin solution.

[0067] The invention also provides surfactant-assisted synthesis of perovskite film obtained by the method.

[0068] The present invention also provides a solar cell assembled by synthesizing a perovskite film assisted by the surfactant.

[0069] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0070] Example 1

[0071] 1. Prepare various solutions required: dissolve 853 mg of stannous chloride and 338 mg of thiourea in 30 ml of deionized water and stir for 36 hours to prepare a tin dioxide quantum dot aqueous solution; slowly add 220 μl of titanium tetrachloride dropwise into 50 ml of deionized water and stir continuously to prepare a titanium tetrachloride aqueous solution; place 2.97 g of lead bromide in a container containing 8 ml of DMF, seal it and heat it at 80°C until it dissolves to prepare a lead bromide DMF solution; dissolve 2 g of cesium bromide in 10 ml of deionized water and add 9.8 mg of sodium dodecylbenzene sulfonate (SDBS) to prepare a cesium bromide aqueous solution with the addition of a surfactant.

[0072] 2. Spin the prepared tin dioxide quantum dot aqueous solution on the etched and cleaned FTO substrate at a speed of 2500 rpm for 30 seconds, and then calcine at 200° C. for 1 hour to obtain a tin dioxide film;

[0073] 3. The tin dioxide film obtained in step (2) was immersed in the titanium tetrachloride solution prepared above, heated in a water bath at 70°C for 30 minutes, washed with deionized water, anhydrous ethanol, and anhydrous methanol in turn, and dried, and then calcined at 200°C for 30 minutes to obtain a tin dioxide-chlorine-containing titanium oxide composite electron transport layer;

[0074] 4. Spin-coat the prepared lead bromide DMF solution on the surface of the electronic layer prepared in step (3) at a speed of 2500 rpm and 90° C. for 30 seconds, and then heat at 100° C. for 30 minutes;

[0075] 5. The prepared cesium bromide aqueous solution with 0.3% molar ratio of sodium dodecylbenzene sulfonate added was spin-coated on the surface of the lead bromide film prepared in step (4) at a speed of 2500 rpm for 20 seconds and heated at 250°C for 30 minutes to prepare high-quality CsPbBr 3 Perovskite light absorbing layer;

[0076] 6. CsPbBr prepared in step (5) 3 The carbon slurry was scraped on the surface of the perovskite light-absorbing layer and annealed at 90 °C for 40 minutes to obtain a back electrode with a thickness of 16 μm, which was assembled into a FTO / SnO structure. 2 -TiO x Cl 4-2x / CsPbBr 3 -SDBS / Carbon all-inorganic perovskite solar cells.

[0077] Example 2

[0078] 1. Prepare various solutions required: dissolve 853 mg of stannous chloride and 338 mg of thiourea in 30 ml of deionized water and stir for 36 hours to prepare a tin dioxide quantum dot aqueous solution; slowly add 220 μl of titanium tetrachloride dropwise into 50 ml of deionized water and stir continuously to prepare a titanium tetrachloride aqueous solution; place 2.97 g of lead bromide in a container containing 10 ml of DMF, seal it and heat it at 80°C until it dissolves to prepare a lead bromide DMF solution; dissolve 2 g of cesium bromide in 10 ml of deionized water and add 8.6 mg of sodium stearate (SS) to prepare a cesium bromide aqueous solution with the addition of a surfactant.

[0079] 2. Spin the prepared tin dioxide quantum dot aqueous solution on the etched and cleaned FTO substrate at a speed of 2500 rpm for 30 seconds, and then calcine at 200° C. for 1 hour to obtain a tin dioxide film;

[0080] 3. The tin dioxide film obtained in step (2) was immersed in the titanium tetrachloride solution prepared above, heated in a water bath at 70°C for 30 minutes, washed with deionized water, anhydrous ethanol, and anhydrous methanol in turn, and dried, and then calcined at 200°C for 30 minutes to obtain a tin dioxide-chlorine-containing titanium oxide composite electron transport layer;

[0081] 4. Spin-coat the prepared lead bromide DMF solution on the surface of the electronic layer prepared in step (3) at a speed of 2500 rpm and 90° C. for 30 seconds, and then heat at 100° C. for 30 minutes;

[0082] 5. Spin the above-prepared 0.3% molar ratio sodium stearate cesium bromide aqueous solution on the surface of the lead bromide film prepared in step (4) at a speed of 2500 rpm for 20 seconds and heat at 250°C for 30 minutes to prepare high-quality CsPbBr 3 Perovskite light absorbing layer;

[0083] 6. CsPbBr prepared in step (5) 3 The carbon slurry was scraped on the surface of the perovskite light-absorbing layer and annealed at 90 °C for 40 minutes to obtain a back electrode with a thickness of 16 μm, which was assembled into a FTO / SnO structure. 2 -TiO x Cl 4-2x / CsPbBr 3 -SS / Carbon all-inorganic perovskite solar cells.

[0084] Example 3

[0085] 1. Prepare various solutions required: dissolve 853 mg of stannous chloride and 338 mg of thiourea in 30 ml of deionized water and stir for 36 hours to prepare a tin dioxide quantum dot aqueous solution; slowly add 220 μl of titanium tetrachloride dropwise into 50 ml of deionized water and stir continuously to prepare a titanium tetrachloride aqueous solution; place 2.97 g of lead bromide in a container containing 8 ml of DMF, seal it and heat it at 80°C until it dissolves to prepare a lead bromide DMF solution; dissolve 2 g of cesium bromide in 10 ml of deionized water and add 7.8 mg of tetrabutylammonium chloride (TBAC) to prepare a cesium bromide aqueous solution with the addition of a surfactant.

[0086] 2. Spin the prepared tin dioxide quantum dot aqueous solution on the etched and cleaned FTO substrate at a speed of 2500 rpm for 30 seconds, and then calcine at 200° C. for 1 hour to obtain a tin dioxide film;

[0087] 3. The tin dioxide film obtained in step (2) was immersed in the titanium tetrachloride solution prepared above, heated in a water bath at 70°C for 30 minutes, washed with deionized water, anhydrous ethanol, and anhydrous methanol in turn, and dried, and then calcined at 200°C for 30 minutes to obtain a tin dioxide-chlorine-containing titanium oxide composite electron transport layer;

[0088] 4. Spin-coat the prepared lead bromide DMF solution on the surface of the electronic layer prepared in step (3) at a speed of 2500 rpm and 90° C. for 30 seconds, and then heat at 100° C. for 30 minutes;

[0089] 5. Spin the above-prepared 0.3% molar ratio tetrabutylammonium chloride cesium bromide aqueous solution on the surface of the lead bromide film prepared in step (4) at a speed of 2500 rpm for 20 seconds and heat at 250°C for 30 minutes to prepare high-quality CsPbBr 3 Perovskite light absorbing layer;

[0090] 6. CsPbBr prepared in step (5) 3 The carbon slurry was scraped on the surface of the perovskite light-absorbing layer and annealed at 90 °C for 40 minutes to obtain a back electrode with a thickness of 16 μm, which was assembled into a FTO / SnO structure. 2 -TiO x Cl 4-2x / CsPbBr 3 -TBAC / Carbon all-inorganic perovskite solar cells.

[0091] Example 4

[0092] 1. Prepare various solutions required: dissolve 853 mg of stannous chloride and 338 mg of thiourea in 30 ml of deionized water and stir for 36 hours to prepare a tin dioxide quantum dot aqueous solution; slowly add 220 μl of titanium tetrachloride dropwise into 50 ml of deionized water and stir continuously to prepare a titanium tetrachloride aqueous solution; place 2.97 g of lead bromide in a container containing 8 ml of DMF, seal it and heat it at 80°C until it dissolves to prepare a lead bromide DMF solution; dissolve 2 g of cesium bromide in 10 ml of deionized water and add 2.6 mg of tetrabutylammonium chloride (TBAC) to prepare a cesium bromide aqueous solution with the addition of a surfactant.

[0093] 2. Spin the prepared tin dioxide quantum dot aqueous solution on the etched and cleaned FTO substrate at a speed of 2500 rpm for 30 seconds, and then calcine at 200° C. for 1 hour to obtain a tin dioxide film;

[0094] 3. The tin dioxide film obtained in step (2) was immersed in the titanium tetrachloride solution prepared above, heated in a water bath at 70°C for 30 minutes, washed with deionized water, anhydrous ethanol, and anhydrous methanol in turn, and dried, and then calcined at 200°C for 30 minutes to obtain a tin dioxide-chlorine-containing titanium oxide composite electron transport layer;

[0095] 4. Spin-coat the prepared lead bromide DMF solution on the surface of the electronic layer prepared in step (3) at a speed of 2500 rpm and 90° C. for 30 seconds, and then heat at 100° C. for 30 minutes;

[0096] 5. Spin the above-prepared 0.1% molar ratio tetrabutylammonium chloride cesium bromide aqueous solution on the surface of the lead bromide film prepared in step (4) at a speed of 2500 rpm for 20 seconds and heat at 250°C for 30 minutes to prepare high-quality CsPbBr 3 Perovskite light absorbing layer;

[0097] 6. CsPbBr prepared in step (5) 3 The carbon slurry was scraped on the surface of the perovskite light-absorbing layer and annealed at 90 °C for 40 minutes to obtain a back electrode with a thickness of 16 μm, which was assembled into a FTO / SnO structure. 2 -TiO x Cl 4-2x / CsPbBr 3 -TBAC / Carbon all-inorganic perovskite solar cells.

[0098] Example 5

[0099] 1. Prepare various solutions required: dissolve 853 mg of stannous chloride and 338 mg of thiourea in 30 ml of deionized water and stir for 36 hours to prepare a tin dioxide quantum dot aqueous solution; slowly add 220 μl of titanium tetrachloride dropwise into 50 ml of deionized water and stir continuously to prepare a titanium tetrachloride aqueous solution; place 2.97 g of lead bromide in a container containing 8 ml of DMF, seal it and heat it at 80°C until it dissolves to prepare a lead bromide DMF solution; dissolve 2 g of cesium bromide in 10 ml of deionized water and add 13 mg of tetrabutylammonium chloride (TBAC) to prepare a cesium bromide aqueous solution with the addition of a surfactant.

[0100] 2. Spin the prepared tin dioxide quantum dot aqueous solution on the etched and cleaned FTO substrate at a speed of 2500 rpm for 30 seconds, and then calcine at 200° C. for 1 hour to obtain a tin dioxide film;

[0101] 3. The tin dioxide film obtained in step (2) was immersed in the titanium tetrachloride solution prepared above, heated in a water bath at 70°C for 30 minutes, washed with deionized water, anhydrous ethanol, and anhydrous methanol in turn, and dried, and then calcined at 200°C for 30 minutes to obtain a tin dioxide-chlorine-containing titanium oxide composite electron transport layer;

[0102] 4. Spin-coat the prepared lead bromide DMF solution on the surface of the electronic layer prepared in step (3) at a speed of 2500 rpm and 90° C. for 30 seconds, and then heat at 100° C. for 30 minutes;

[0103] 5. Spin the above-prepared 0.5% molar ratio tetrabutylammonium chloride cesium bromide aqueous solution on the surface of the lead bromide film prepared in step (4) at a speed of 2500 rpm for 20 seconds and heat at 250°C for 30 minutes to prepare high-quality CsPbBr 3 Perovskite light absorbing layer;

[0104] 6. CsPbBr prepared in step (5) 3 The carbon slurry was scraped on the surface of the perovskite light-absorbing layer and annealed at 90 °C for 40 minutes to obtain a back electrode with a thickness of 16 μm, which was assembled into a FTO / SnO structure. 2 -TiO x Cl 4-2x / CsPbBr 3 -TBAC / Carbon all-inorganic perovskite solar cells.

[0105] Comparative Example (corresponding to the original film or original in the attached figure)

[0106] 1. Prepare various solutions required: dissolve 853 mg of stannous chloride and 338 mg of thiourea in 30 ml of deionized water and stir for 36 hours to prepare a tin dioxide quantum dot aqueous solution; slowly add 220 μl of titanium tetrachloride to 50 ml of deionized water and stir continuously to prepare a titanium tetrachloride aqueous solution; place 2.97 g of lead bromide in a container containing 8 ml of DMF, seal it at 80 ° C and heat it until dissolved to prepare a lead bromide DMF solution; dissolve 2 g of cesium bromide in 10 ml of deionized water to prepare a control group cesium bromide aqueous solution.

[0107] 2. Spin the prepared tin dioxide quantum dot aqueous solution on the etched and cleaned FTO substrate at a speed of 2500 rpm for 30 seconds, and then calcine at 200° C. for 1 hour to obtain a tin dioxide film;

[0108] 3. The tin dioxide film obtained in step (2) was immersed in the titanium tetrachloride solution prepared above, heated in a water bath at 70°C for 30 minutes, washed with deionized water, anhydrous ethanol, and anhydrous methanol in turn, and dried, and then calcined at 200°C for 30 minutes to obtain a tin dioxide-chlorine-containing titanium oxide composite electron transport layer;

[0109] 4. Spin-coat the prepared lead bromide DMF solution on the surface of the electronic layer prepared in step (3) at a speed of 2500 rpm and 90° C. for 30 seconds, and then heat at 100° C. for 30 minutes;

[0110] 5. The prepared control group cesium bromide aqueous solution was spin-coated on the surface of the lead bromide film prepared in step (4) at a speed of 2500 rpm for 20 seconds and heated at 250°C for 30 minutes to prepare high-quality CsPbBr 3 Perovskite light absorbing layer;

[0111] 6. CsPbBr prepared in step (5) 3 The carbon slurry was scraped on the surface of the perovskite light-absorbing layer and annealed at 90 °C for 40 minutes to obtain a back electrode with a thickness of 16 μm, which was assembled into a FTO / SnO structure. 2 -TiO x Cl 4-2x / CsPbBr 3 / Carbon all-inorganic perovskite solar cells.

[0112] Example 1 The SEM of the perovskite solar cell obtained is as follows Figure 1 As shown, the SEM of the perovskite solar cell obtained in Comparative Example 1 is as follows Figure 2As shown. From the SEM image, it can be seen that the perovskite film prepared by adding sodium dodecylbenzene sulfonate surfactant to the cesium bromide precursor is uniform and dense, has a large grain size, and completely covers the electron transport layer without holes. This is conducive to reducing short circuits, while reducing film defect states, inhibiting charge recombination, and improving the output of the assembled perovskite solar cell photoelectric conversion efficiency.

[0113] The photovoltaic performance parameters of the perovskite solar cells of the above embodiments and comparative examples are shown in Tables 1 and Figure 3 shown.

[0114] Table 1 Photovoltaic performance parameters of various perovskite solar cells

[0115]

[0116]

[0117] It can be seen from Table 1 that various photovoltaic performance parameters of the perovskite solar cells obtained in Examples 1 to 5 are improved compared with those in the comparative example.

[0118] The perovskite solar cells of the embodiment and the comparative example were tested, and their JV curves were as follows: Figure 3 As shown, the stability diagram of the perovskite solar cell of Example 3 and the comparative example under the natural environment condition of 85% high relative humidity for 30 days is as follows Figure 4 The open circuit voltage of perovskite solar cells is 1.45-1.6V, and the short circuit current is 6.5-7.8mA·cm -2 , a high-performance CsPbBr prepared based on surfactant as an additive with a filling factor of 0.70-0.85 and a photoelectric conversion efficiency of 7.5-10.5% 3 All-inorganic perovskite solar cells.

[0119] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for synthesizing a perovskite film assisted by a surfactant, characterized in that: The following steps are included: (1) coating a tin dioxide quantum dot aqueous solution on a substrate and then sintering it to obtain a tin dioxide electronic layer; (2) soaking the obtained tin dioxide electron layer in a titanium tetrachloride aqueous solution and then calcining it to obtain a tin dioxide-chlorine-containing titanium oxide composite electron transport layer; (3) coating an N,N-dimethylformamide solution of lead bromide on the obtained tin dioxide-chlorine-containing titanium oxide composite electron transport layer and then annealing to obtain a lead bromide thin film; (4) coating a cesium bromide aqueous solution containing a surfactant on the obtained lead bromide film and then annealing to obtain a CsPbBr3 perovskite film; (5) coating the conductive paste on the obtained CsPbBr3 perovskite film and then performing a heat treatment to obtain a surfactant-assisted synthesized perovskite film; The molar ratio of the surfactant to cesium bromide in step (4) is 0.1 to 1:100; The surfactant comprises one or more of sulfonate anionic surfactants, sulfate anionic surfactants, fatty acid anionic surfactants, succinate anionic surfactants, ammonium salt cationic surfactants, quaternary ammonium salt cationic surfactants, amino acid zwitterionic surfactants, imidazoline zwitterionic surfactants, lecithin zwitterionic surfactants, betaine zwitterionic surfactants and nonionic surfactants; The sulfonate type anionic surfactant comprises one or more of sodium dodecylbenzene sulfonate, dodecylbenzene sulfonic acid and sodium 1-butane sulfonate.

2. The method according to claim 1, characterized in that The concentration of the tin dioxide quantum dot aqueous solution in step (1) is 0.1-1 mol / L; The sintering temperature is 200-250° C. and the sintering time is 1-2 hours.

3. The method according to claim 1 or 2, characterized in that: The concentration of the titanium tetrachloride aqueous solution in step (2) is 0.03-0.1 mol / L; The soaking temperature is 70-80°C and the soaking time is 30-50 minutes.

4. The method according to claim 3, characterized in that The calcination temperature in step (2) is 160-220° C. and the calcination time is 30-60 min.

5. The method according to claim 1, 2 or 4, characterized in that: The concentration of the lead bromide solution in N,N-dimethylformamide in step (3) is 0.8-1.2 mol / L; The coating environment temperature is 60-110°C; The annealing temperature is 90-110° C. and the annealing time is 30-60 min.

6. The method according to claim 5, characterized in that The concentration of cesium bromide in the cesium bromide aqueous solution containing a surfactant in step (4) is 0.8 to 1.5 mol / L; The annealing temperature is 200-250° C. and the annealing time is 30-60 min.

7. The method according to claim 1, 2, 4 or 6, characterized in that: The heating treatment in step (5) is carried out at a temperature of 90 to 130° C. and for a time of 30 to 60 minutes.

8. The surfactant-assisted synthesis of perovskite film obtained by the method according to any one of claims 1 to 7.

9. A solar cell assembled by synthesizing a perovskite film assisted by the surfactant according to claim 8.

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