Perovskite solar cell and preparation method thereof

Abstract

The application belongs to the technical field of new energy materials and devices, and particularly relates to a perovskite solar cell and a preparation method thereof. The perovskite solar cell comprises a conductive glass layer, an electron transport layer, an interface modification layer, a perovskite light absorption layer, a hole transport layer and a metal electrode layer. The perovskite light absorption layer is doped with arginine of a certain concentration and is subjected to an annealing process. The interface modification layer is a sodium alginate film layer. The perovskite light absorption layer film shows stronger crystallinity and a smoother surface after being doped with arginine. In combination with the interface modification of the sodium alginate, the dangling bonds on the surface of the perovskite layer between the interface of the electron transport layer and the perovskite light absorption layer can be passivated, so as to reduce the binding of deep level defects to carriers, effectively reduce the contact between the electron transport layer and the hole transport layer, reduce the leakage current, improve the photoelectric conversion efficiency, and be beneficial to blocking the penetration of oxygen and reducing the oxidation of the perovskite material.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of new energy materials and devices, and particularly relates to a perovskite solar cell and a preparation method thereof. BACKGROUND

[0002] In recent years, the demand for electricity by human beings has increased dramatically, and the reserves of traditional fossil energy have been far from enough. Therefore, solar cells are paid more and more attention. As an emerging solar cell, the perovskite solar cell is highly expected due to its excellent photovoltaic characteristics and great development potential. However, the photovoltaic characteristics such as the photoelectric conversion efficiency and stability of the perovskite solar cell are relatively poor and difficult to be industrialized, which has been a technical bottleneck restricting its wide application. An important factor affecting the photovoltaic characteristics is the micro defects existing in the perovskite structure material.

[0003] The existing research and technology show that the perovskite solar cell generates excitons (electron-hole pairs) under light conditions. Due to the weak exciton binding energy of the perovskite material and the high carrier mobility, the excitons are separated into electrons and holes under the action of the built-in electric field in the p-n junction and then move to the two sides of the cell. The photo-generated holes move to the p region, and the photo-generated electrons move to the n region, thereby forming a current in the closed path, which is the working principle of the perovskite solar cell. The common perovskite solar cell structure includes, in sequence, a conductive glass, an electron transport layer, a perovskite light-absorbing layer, a hole transport layer and a metal electrode. Due to many interference factors existing in the actual crystallization process, a large number of defects exist in the crystal of the perovskite light-absorbing layer, mainly including interface defects between layers and anti-site ions, grain boundaries and other defects existing in the perovskite light-absorbing layer. These defects can capture free charges, resulting in a decrease in the photovoltaic performance of the device. Many studies have shown that doping certain substances can effectively passivate defects.

[0004] The interface defects are mainly treated by modifying the interface.

[0005] The defects in the perovskite light-absorbing layer are mainly treated by adding Lewis acids / bases (such as small-molecule organic substances and the like) and metal ions and the like to reduce the influence of the defects, thereby improving the actual photovoltaic performance and stability of the battery device.

[0006] In the actual preparation of a traditional perovskite solar cell, the electron transport layer is often made of titanium dioxide (TiO2) or tin dioxide (SnO2), the hole transport layer is mainly made of spiro-MeOTAD material, and the metal electrode is commonly made of silver electrode or gold electrode. In the actual perovskite solar cell, CH3NH3PbI3 (MAPbI3) is a commonly used perovskite light-absorbing layer material, which has a perovskite crystal structure. Studies have found that doping amino propionic acid hydrochloride (APAC) or nickel ions (Ni2+) in the perovskite material for passivation can improve the photoelectric conversion efficiency of the perovskite solar cell, but the price is relatively high, and heavy metals are harmful to the human body and the environment, in addition, the operation precision of controlling the dosage is relatively high, so it is relatively difficult to use in practice. SUMMARY

[0007] The present application aims to at least partially solve the above problems, based on the discovery and understanding of the inventors of the following facts and problems, the main problems of the perovskite solar cell to be improved are as follows: first, the perovskite material of the perovskite solar cell has small crystal grains and dense grain boundaries, which leads to large carrier transport hindrance and reduces the photoelectric conversion efficiency of the device; second, there are interface defects between the layers of the perovskite solar cell, which bind part of the normally transported carriers, resulting in a decrease in the photoelectric conversion efficiency and output performance of the battery device. In addition, due to the existence of defects at the interface, water vapor and oxygen from the outside will reduce the stability of the perovskite solar cell.

[0008] Embodiments of the present application propose a perovskite solar cell preparation method, comprising the following steps:

[0009] (1) preparing a tin dioxide electron transport layer on a conductive glass;

[0010] (2) preparing a sodium alginate interface modification layer on the electron transport layer;

[0011] (3) preparing a perovskite light-absorbing layer on the interface modification layer;

[0012] (4) preparing a hole transport layer on the perovskite light-absorbing layer;

[0013] (5) sputtering to prepare a metal electrode layer on the hole transport layer.

[0014] The above perovskite solar cell preparation method produces a perovskite solar cell, which includes a conductive glass layer, an electron transport layer (tin dioxide layer), an interface modification layer (sodium alginate layer), a perovskite light-absorbing layer (arginine-doped perovskite thin film), a hole transport layer, and a metal electrode layer. The thin film of the perovskite light-absorbing layer is doped with a certain concentration of arginine and subjected to an annealing process, and the interface modification layer is a sodium alginate thin film layer.

[0015] In some embodiments, the preparation of the sodium alginate interface modification layer on the electron transport layer comprises the following steps:

[0016] (1) preparing a sodium alginate aqueous solution, so that the mass-volume concentration of the sodium alginate aqueous solution is 0.15-0.4 mg / ml, and after stirring and dissolving, an interface modification liquid is obtained;

[0017] (2) spin-coating the interface modification liquid on the surface of the electron transport layer to form an interface modification layer;

[0018] (3) annealing the sample of step (2) to form a sodium alginate interface modification layer on the electron transport layer.

[0019] Optionally, the spin-coating speed of the interface modification liquid is 2800-3200 rpm, and the spin-coating amount is 35-45 μL.

[0020] Optionally, the annealing process is heating to 130-150 °C and holding for 4-5 minutes.

[0021] In some embodiments, the preparation of the perovskite light-absorbing layer on the interface modification layer comprises the following steps:

[0022] (1) dissolving and stirring arginine in N,N-dimethylformamide as a first solvent under vacuum conditions to prepare an arginine precursor solution;

[0023] (2) using a mixture of N,N-dimethylformamide and dimethyl sulfoxide as a second solvent, the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide in the second solvent being (47-9):(3-1), adding PbI2 and the arginine precursor solution into the second solvent, and stirring to obtain a first perovskite precursor solution;

[0024] (3) dissolving a mixture of formamidinium iodide (FAI, Formamidinium Iodide), methylammonium chloride (MACl, Methylammonium Chloride), and methylammonium bromide (MABr, Methylammonium Bromide) in isopropanol as a third solvent, and heating and stirring to prepare a second perovskite precursor solution;

[0025] (4) spin-coating the first perovskite precursor solution on the sodium alginate interface modification layer and annealing to form a first perovskite layer;

[0026] (5) spin-coating the second perovskite precursor solution on the first perovskite layer and annealing to prepare a perovskite light-absorbing layer.

[0027] Optionally, in the arginine precursor solution, the mass-volume concentration of arginine is 0.04-0.1 mg / ml.

[0028] Optionally, in the second perovskite precursor solution, the mixing ratio of formamidinium iodide, formamidinium chloride and formamidinium bromide is (9-10):(2-1):1.

[0029] Optionally, when the first perovskite precursor solution is spin-coated on the sodium alginate interface modification layer, the spin-coating speed is 1500 rpm, and the spin-coating amount is 80-85 μL; the annealing process is heating to 65-70℃, and keeping for 10-15 seconds.

[0030] Optionally, when the second perovskite solution is spin-coated on the first perovskite layer, the spin-coating speed is 1500 rpm, and the spin-coating amount is 100-105 μL; the annealing process is heating to 150℃, and keeping for 15-16 minutes.

[0031] In some embodiments of the present application, a perovskite solar cell prepared by the above method is provided.

[0032] The perovskite solar cell prepared by the method has the following advantages:

[0033] The perovskite solar cell prepared by the method has the following advantages:

[0034] Additional aspects and advantages of the application will be made apparent by the following description. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0036] Figure 1 The structure of the perovskite solar cell after defect passivation in embodiment 1 according to the present application is shown in the schematic diagram.

[0037] Figure 2 Figure 2 is a current density-voltage (J-V) curve test diagram of the perovskite solar cell according to the embodiment 1 and the comparative example 1 of the present application.

[0038] Figure 3 Figure 3 is a dark state current density-voltage (J-V) curve test diagram of the perovskite solar cell according to the embodiment 1 and the comparative example 1 of the present application.

[0039] Figure 4 Figure 4 is an X-ray diffraction spectrum of the perovskite light-absorbing layer thin film in the perovskite solar cell according to the embodiment 1 and the comparative example 1 of the present application.

[0040] Figure 5 Figure 5 is an EIS electrochemical impedance spectrum of the perovskite solar cell according to the embodiment 1 and the comparative example 1 of the present application.

[0041] Figure 6 Figure 6 is an ultraviolet-visible absorption spectrum of the perovskite solar cell according to the embodiment 1 and the comparative example 1 of the present application.

[0042] Figure 7 is a photoelectric conversion efficiency stability test of the perovskite solar cell according to the embodiment 1 and the comparative example 1 of the present application; wherein figure 7(a) is under indoor air environment conditions, figure 7(b) is under a standard solar light intensity irradiation environment, and figure 7(c) is under nitrogen environment conditions. DETAILED DESCRIPTION

[0043] The embodiments of the present application are described in detail below, the embodiments of the present application are shown in the accompanying drawings, the embodiments described by referring to the accompanying drawings are exemplary, and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0044] The embodiments of the present application propose a perovskite solar cell preparation method, comprising the following steps:

[0045] (1) preparing a tin dioxide electron transport layer on a conductive glass;

[0046] (2) preparing a sodium alginate interface modification layer on the electron transport layer;

[0047] (3) preparing a perovskite light-absorbing layer on the interface modification layer;

[0048] (4) preparing a hole transport layer on the perovskite light-absorbing layer;

[0049] (5) sputtering to prepare a metal electrode layer on the hole transport layer.

[0050] The structure schematic diagram of the perovskite solar cell prepared by the embodiments of the present application is shown in Figure 1 .

[0051] In step (1) of the embodiment of the present application, the conductive glass is scrubbed with non-woven fabric soaked in cleaning agent, then rinsed with deionized water and ethanol, and then ultrasonic cleaned with ethanol, deionized water, ethanol, acetone and ethanol in sequence. After the above cleaning, the conductive glass is dried with nitrogen and subjected to ultraviolet-ozone treatment. SnO2 nanocrystal solution is diluted with ultrapure water and subjected to suction filtration to prepare an electron transport layer solution, which is then spin-coated onto the conductive glass in an air environment and at room temperature, and subjected to annealing treatment to prepare an electron transport layer.

[0052] In step (2) of the embodiment of the present application, sodium alginate is dissolved in ultrapure water and stirred to prepare an interface modification solution. After the spin-coating of the electron transport layer solution in step (2) and the completion of annealing, the interface modification solution is spin-coated on the electron transport layer prepared in step (1) and subjected to annealing treatment to prepare an interface modification layer.

[0053] In step (3) of the embodiment of the present application, arginine is dissolved in N,N-dimethylformamide as a solvent under vacuum and stirred to prepare an arginine precursor solution. A mixture of N,N-dimethylformamide and dimethyl sulfoxide is used as a first solvent, PbI2 and the arginine precursor solution are added to the first solvent and stirred to prepare a first perovskite precursor solution; a mixture of FAI, MACl and MABr is dissolved in isopropanol as a solvent and heated and stirred to prepare a second perovskite precursor solution.

[0054] After stirring, the first perovskite precursor solution is spin-coated on the interface modification layer prepared in step (2) and subjected to annealing treatment to form a first perovskite layer; the second perovskite precursor solution is spin-coated on the first perovskite layer in the same environment and subjected to annealing treatment to prepare a perovskite light-absorbing layer.

[0055] In step (4) of the embodiment of the present application, Li-TFSI (lithium bis(trifluoromethanesulfonyl)imide) is dissolved in acetonitrile as a solvent to prepare a Li-TFSI acetonitrile solution. Spiro-MeOTAD is dissolved in chlorobenzene as a solvent, and tBP and the Li-TFSI acetonitrile solution are added to prepare a hole transport layer solution. The hole transport layer solution is subjected to suction filtration in a vacuum environment, and then spin-coated on the perovskite light-absorbing layer in step (4) to prepare a hole transport layer, which is then placed in a drying oven for oxidation for 24 hours after the spin-coating is completed.

[0056] In step (5) of the embodiment of the present application, a metal electrode is prepared by sputtering a metal electrode on the hole transport layer using a magnetron sputtering instrument or an evaporation deposition method.

[0057] The perovskite solar cell prepared by the method has a perovskite light-absorbing layer film, which, after being doped with arginine, has stronger crystallinity and a smoother surface, and the interface modification of sodium alginate can passivate the dangling bonds on the surface of the perovskite layer between the electron transport layer and the perovskite light-absorbing layer, thereby reducing the binding of deep level defects to carriers, effectively reducing the contact between the electron transport layer and the hole transport layer, reducing the leakage current, improving the photoelectric conversion efficiency, and being conducive to blocking the penetration of oxygen and reducing the oxidation of perovskite materials.

[0058] According to some embodiments of the present application, the preparation of the sodium alginate interface modification layer on the electron transport layer comprises the following steps:

[0059] (1) preparing a sodium alginate aqueous solution, so that the mass / volume concentration of the sodium alginate aqueous solution is 0.15-0.4 mg / ml, and the interface modification liquid is obtained after stirring and dissolving;

[0060] (2) spin coating the interface modification liquid on the surface of the electron transport layer to form an interface modification layer;

[0061] (3) annealing the sample of step (2) to form a sodium alginate interface modification layer on the electron transport layer.

[0062] According to some embodiments of the present application, the spin coating speed of the interface modification liquid is 2800-3200 rpm, and the spin coating amount is 35-45 μL.

[0063] According to some embodiments of the present application, the annealing process is heating to 130-150℃ and holding for 4-5 minutes.

[0064] According to some embodiments of the present application, the preparation of the perovskite light-absorbing layer on the interface modification layer comprises the following steps:

[0065] (1) dissolving and stirring arginine in N,N-dimethylformamide as a first solvent under vacuum conditions to prepare an arginine precursor solution;

[0066] (2) using a mixture of N,N-dimethylformamide and dimethyl sulfoxide as a second solvent, the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide in the second solvent being (47-9):(3-1), adding PbI2 and the arginine precursor solution into the second solvent, and stirring to obtain a first perovskite precursor solution;

[0067] (3) using isopropanol as a third solvent, dissolving a mixed solute of formamidinium iodide (FAI, Formamidinium Iodide), methylammonium chloride (MACl, Methylammonium Chloride), and methylammonium bromide (MABr, Methylammonium Bromide) by heating and stirring to prepare a second perovskite precursor solution;

[0068] (4) spin coating the first perovskite precursor solution on the sodium alginate interface modification layer and performing annealing treatment to form a first perovskite layer;

[0069] (5) spin coating the second perovskite precursor solution on the first perovskite layer and performing annealing treatment to prepare a perovskite light-absorbing layer.

[0070] According to some embodiments of the present application, the mass-volume concentration of arginine in the arginine precursor solution is 0.04-0.1 mg / ml.

[0071] According to some embodiments of the present application, the mixing ratio of formamidinium iodide, methylammonium chloride, and methylammonium bromide in the second perovskite precursor solution is (9-10):(2-1):1.

[0072] According to some embodiments of the present application, when the first perovskite precursor solution is spin coated on the sodium alginate interface modification layer, the spin coating speed is 1500 rpm, and the spin coating amount is 80-85 μL; the annealing treatment process is heating to 65-70℃ and maintaining for 10-15 seconds.

[0073] According to some embodiments of the present application, when the second perovskite solution is spin coated on the first perovskite layer, the spin coating speed is 1500 rpm, and the spin coating amount is 100-105 μL; the annealing treatment process is heating to 150℃ and maintaining for 15-16 minutes.

[0074] In the perovskite solar cell prepared by the method, arginine as a small molecule organic matter plays a role of a condensation nucleus for perovskite film formation, so as to improve the film forming property of perovskite material, increase the grain size of perovskite crystal, and reduce the loss of carriers. The amino group, carboxyl group, and other functional groups of arginine can form coordination bonds and hydrogen bonds with various defects in perovskite, so as to optimize the lattice structure distorted due to defects. The Lewis base functional group (such as the amino group) can coordinate with PbI type inversion defects (lead ions replacing iodine ions), so as to offset the binding ability of the defects to free carriers. Compared with a traditional perovskite solar cell device, the method improves the photoelectric performance of the cell device. After connecting to an external circuit, the structure enables the photogenerated carriers to flow into the external circuit under the action of the internal potential difference formed by the structure after the perovskite solar cell receives light to form photogenerated carriers, thereby forming a stable photogenerated current.

[0075] The perovskite solar cell in the embodiment of the application is prepared by the method of the embodiment of the application.

[0076] The specific embodiments of the application are described in detail below. All the embodiments are exemplary and are intended to explain the application, and cannot be understood as limiting the application.

[0077] Embodiment 1

[0078] 1. ITO glass is used, the sheet resistance is 15, the transmittance is 93%, the size of the substrate is 15*15mm 2 , and the thickness is 0.7mm. The conductive glass is scrubbed with non-woven fabric soaked in detergent, then washed with deionized water and ethanol, and then ultrasonically cleaned with ethanol, deionized water, ethanol, acetone and ethanol for 15 minutes respectively. After the above cleaning is completed, the conductive glass is dried with nitrogen before use and then treated with ultraviolet-ozone for 15 minutes.

[0079] 2. 500ul of SnO2 nanocrystal solution is taken by a pipette and added to 2.5ml of ultrapure water, and then placed in a refrigerator for standby. Before use, the solution is filtered by connecting a 0.22um nylon filter head with a 1ml syringe to prepare an electron transport layer solution, and then 50ul of the electron transport layer solution is taken by a pipette and spin-coated on the conductive glass at a spin speed of 3000rpm / 30s, and then annealed on a 145℃ hot stage for 30 minutes to prepare an electron transport layer.

[0080] 3. Sodium alginate is dissolved in ultrapure water to 0.35mg / ml, and then stirred for 3 hours to prepare an interface modification solution. After the spin-coating of the electron transport layer solution in step 2 above is completed and the annealing is finished, 40ul of the interface modification solution is spin-coated on the electron transport layer at a spin speed of 3000rpm / 30s, and then placed on a hot stage at 150℃ for annealing for 5 minutes to prepare an interface modification layer.

[0081] 4. Arginine is dissolved in a mixture of "ultrapure water:N,N-dimethylformamide=10:1" as a solvent under vacuum conditions to a concentration of 0.08mg / ml, and then magnetically stirred for 1 hour to prepare an arginine precursor solution. A mixture of "N,N-dimethylformamide:dimethyl sulfoxide=47:3" by volume is used as solvent 1, 0.9g of PbI2 and 20ul of the above arginine precursor solution are added to the solvent 1 to prepare a first perovskite precursor solution, and then heated and stirred on a 75℃ hot stage for 12-15 hours; 0.06g of FAI, 0.006g of MACl and 0.006g of MABr are added to 1ml of isopropanol as a solvent to prepare a perovskite solution 2, and then stirred at room temperature in a low-oxygen and dry environment for 12-15 hours.

[0082] In a vacuum and dry environment, the first perovskite precursor solution was spin-coated onto the interface modification layer at a rotation speed of 1500 rpm for 30 seconds and an acceleration of 800 m / s². After spin-coating, the solution was annealed at 70°C for 15 seconds to form perovskite layer 1. Perovskite solution 2 was spin-coated onto the perovskite layer 1 at the same rotation speed, and then annealed at 150°C for 10 minutes to prepare a perovskite light-absorbing layer.

[0083] 5. Dissolve 1560 mg of Li-TFSI (lithium bis(trifluoromethanesulfonylimide)) in 3 ml of acetonitrile and stir for 3 hours to prepare a Li-TFSI acetonitrile solution. Weigh 72.6 mg of Spiro-MeOTAD and 8 mg of pyrethroids into a reagent bottle using an electronic balance. Add 1 ml of chlorobenzene to the reagent bottle using a pipette. Then add 29 μL of tBP and 18.0 μL of the above Li-TFSI acetonitrile solution and stir for 2 hours under nitrogen atmosphere. Filter the above solution in a vacuum glove box using a syringe-nylon filter head (organic) combination. Spin-coat the solution at 4000 rpm for 30 seconds for 30 seconds to prepare a hole transport layer. After spin-coating, place the layer in a petri dish and oxidize it in a drying oven for 24 hours.

[0084] 6. A metallic silver (Ag) electrode was sputtered onto the hole transport layer using magnetron sputtering technology, thus completing the fabrication of the metal electrode. The final device structure is shown in the attached figure. Figure 1 As shown in the figure. The interface-modified perovskite solar cell doped with amino acids prepared using the method of this embodiment exhibits an average photoelectric conversion efficiency of 21.4% and a maximum photoelectric conversion efficiency of 22.08% under simulated sunlight. Its current-voltage curve is shown in the figure. Figure 2 As shown in Figure 7(a), “After treatment”, the photoelectric conversion efficiency is 16.8% after 720 hours of storage in an indoor air environment; as shown in Figure 7(b), “After treatment”, the photoelectric conversion efficiency is 17.2% after 240 hours of continuous irradiation with a standard solar intensity; and as shown in Figure 7(c), “After treatment”, the photoelectric conversion efficiency is 20.5% after 720 hours of storage in a nitrogen environment.

[0085] Example 2

[0086] Except that the interface modification liquid of "sodium alginate with a concentration of 0.35 mg / ml" is replaced by a solution of "0.15 mg of sodium alginate added in 1 ml of ultrapure water" as the interface modification liquid, the rest is the same as Example 1. The average photoelectric conversion efficiency of a perovskite solar cell doped with amino acids obtained by the preparation method of the present example is 20.7% under simulated sunlight environment, the highest photoelectric conversion efficiency is 21.6%, the photoelectric conversion efficiency is 16.3% after being stored in indoor air environment for 720 hours, and the photoelectric conversion efficiency is 16.7% after being irradiated with a standard sunlight for 240 hours.

[0087] Example 3

[0088] Except that the arginine precursor solution is replaced by "an arginine precursor solution in which arginine is dissolved in a mixed solution of 'ultrapure water:N,N-dimethylformamide = 10:1' under vacuum conditions to a concentration of 0.04 mg / ml", the rest is the same as Example 1. The average photoelectric conversion efficiency of a perovskite solar cell doped with amino acids obtained by the preparation method of the present example is 21.1% under simulated sunlight environment, the highest photoelectric conversion efficiency is 21.8%, the photoelectric conversion efficiency is 16.5% after being stored in indoor air environment for 720 hours, and the photoelectric conversion efficiency is 16.8% after being irradiated with a standard sunlight for 240 hours.

[0089] Comparative Example 1

[0090] Except that the steps of "arginine doping" and "sodium alginate interface layer modification" are removed, the rest is the same as Example 1. The average photoelectric conversion efficiency of a perovskite solar cell obtained by the preparation method of the present example is 19.3% under simulated sunlight environment, and the highest photoelectric conversion efficiency is 19.93%. The current-voltage curve is shown in Figure 1 "Before treatment". Figure 3 The dark current density-voltage (J-V) curve test diagram of Example 1 and the present comparative example is shown, which shows that the dark leakage current of the device after treatment is significantly reduced, indicating that the loss of effective current is reduced. Figure 4 The X-ray diffraction spectrum of the perovskite light-absorbing layer film of Example 1 and the present comparative example is shown, which shows that the relative height of the perovskite peak rises, while the relative height of the lead iodide peak decreases, indicating that the crystallinity of the perovskite light-absorbing layer after treatment is improved. Figure 5 The EIS electrochemical impedance spectrum of Example 1 and the present comparative example is shown, which shows that the interface transmission resistance of the device after treatment is reduced from 24.4 kΩ to 10 kΩ, indicating that the carrier transport is less hindered, and the defects at the interface between the electron transport layer and the perovskite light-absorbing layer are passivated; Figure 6The UV-visible absorption spectrum of Example 1 and the present comparative example shows that the light absorption ability of the perovskite light absorbing layer film after treatment is improved; Figure 7(a) shows that the photoelectric conversion efficiency is 14.5% after being stored in the indoor air environment for 720 hours; Figure 7(b) shows that the photoelectric conversion efficiency is 14.0% after being irradiated with a standard sunlight intensity for 240 hours; and Figure 7(c) shows that the photoelectric conversion efficiency is 16.1% after being stored in the nitrogen environment for 720 hours. In the figures, the post-treatment indicates Example 1, and the pre-treatment indicates Comparative Example 1.

[0091] Comparative Example 2

[0092] Except for removing the "sodium alginate interface modification" step, the rest is the same as Example 1. The interface modified perovskite solar cell doped with amino acids obtained by the preparation method of the present example has an average photoelectric conversion efficiency of 20.7% under simulated sunlight environment, the highest photoelectric conversion efficiency is 21.3%, the photoelectric conversion efficiency is 16.2% after being stored in the indoor air environment for 720 hours, and the photoelectric conversion efficiency is 16.4% after being irradiated with a standard sunlight intensity for 240 hours.

[0093] The above only describes the preferred specific embodiments of the present application, but the protection scope of the present application is not limited to the above examples. Any changes and modifications within the scope of the present application should be considered as the protection scope of the present application.

Claims

1. A method for preparing a perovskite solar cell, characterized by, The method comprises the following steps: (1) preparing a tin dioxide electron transport layer on a conductive glass; (2) preparing a sodium alginate interface modification layer on the electron transport layer; (3) preparing a perovskite light-absorbing layer on the interface modification layer; (4) preparing a hole transport layer on the perovskite light-absorbing layer; (5) sputtering a metal electrode layer on the hole transport layer; The method for preparing the perovskite light-absorbing layer on the interface modification layer comprises the following steps: (1) dissolving arginine in N,N-dimethylformamide as a first solvent under vacuum to prepare an arginine precursor solution; (2) dissolving PbI2 and the arginine precursor solution in a mixture of N,N-dimethylformamide and dimethyl sulfoxide as a second solvent, wherein the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide in the second solvent is (47-9):(3-1), to obtain a first perovskite precursor solution; (3) dissolving a mixture of formamidinium iodide, chloromethylamine and bromomethylamine in isopropanol as a third solvent, and stirring under heating to obtain a second perovskite precursor solution; (4) spin-coating the first perovskite precursor solution on the sodium alginate interface modification layer, and performing annealing treatment to form a first perovskite layer; (5) spin-coating the second perovskite precursor solution on the first perovskite layer, and performing annealing treatment to obtain the perovskite light-absorbing layer.

2. The method of claim 1, wherein the perovskite solar cell is prepared by the steps of: The method for preparing the sodium alginate interface modification layer on the electron transport layer comprises the following steps: (1) preparing a sodium alginate aqueous solution, wherein the mass-volume concentration of the sodium alginate aqueous solution is 0.15-0.4 mg / ml, and stirring and dissolving to obtain an interface modification solution; (2) spin-coating the interface modification solution on the surface of the electron transport layer to form an interface modification layer; (3) performing annealing treatment on the sample of step (2) to form the sodium alginate interface modification layer on the electron transport layer.

3. The method for preparing perovskite solar cells according to claim 2, characterized in that, The spin-coating speed of the interface modification solution is 2800-3200 rpm, and the spin-coating amount is 35-45 μL.

4. The method for preparing a perovskite solar cell according to claim 2, characterized in that, The annealing treatment is performed by heating to 130-150 ℃ and maintaining for 4-5 minutes.

5. The method for preparing a perovskite solar cell according to claim 1, characterized in that, In the arginine precursor solution, the mass-volume concentration of arginine is 0.04-0.1 mg / ml.

6. The method for preparing a perovskite solar cell according to claim 1, characterized in that, In the second perovskite precursor solution, the mixing ratio of formamidinium iodide, chloromethylamine and bromomethylamine is (9-10):(2-1):

1.

7. The method for preparing a perovskite solar cell according to claim 1, characterized in that, When the first perovskite precursor solution is spin-coated on the sodium alginate interface modification layer, the spin-coating speed is 1500 rpm, and the spin-coating amount is 80-85 μL; the annealing treatment is performed by heating to 65-70 ℃ and maintaining for 10-15 seconds.

8. The method for preparing a perovskite solar cell according to claim 1, characterized in that, When the second perovskite solution is spin-coated on the first perovskite layer, the spin-coating speed is 1500 rpm, and the spin-coating amount is 100-105 μL; the annealing treatment is performed by heating to 150 ℃ and maintaining for 15-16 minutes.

9. A perovskite solar cell, characterized by, The method is prepared by any one of claims 1-8.

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