A preparation method for an efficient and stable perovskite solar cell

Abstract

The present invention relates to a preparation method of an efficient and stable perovskite solar cell. During the preparation of the perovskite solar cell, a perovskite thin film prepared by adding a passivation defect additive to a perovskite precursor solution is used as the perovskite light-absorbing layer. The small molecule structure of the passivation defect additive includes a carbonyl group, an amino group, a benzene ring, and a fluorine group. Among them, the carbonyl group can bind to Pb<supgt;2+< / supgt; ions with insufficient coordination in the perovskite solution, or bind to other defective state cations to form a Lewis complex, thereby passivating the film defects; the fluorine group has strong hydrophobicity, which can improve the stability of the perovskite solar device and is an effective charge transfer channel between the perovskite layer and the hole transport layer; and the amino group improves the coordination ability of C=O and Pb<supgt;2+< / supgt>, reduces the defects on the grain surface, improves the perovskite film formation quality, and the combination of the amino group and iodide can inhibit ion migration, further enhancing the passivation effect.

Description

Technical Field

[0001] The present invention belongs to the field of perovskite solar cells, and particularly relates to a preparation method of an efficient and stable perovskite solar cell. Background Art

[0002] With the continuous development of human society, the demand for energy is increasing. Traditional energy sources such as oil, natural gas, and coal are all non-renewable energy sources. Not only is the storage volume decreasing day by day, but it also brings relatively large pollution to the environment. Therefore, it is extremely urgent and important to vigorously develop renewable green clean energy. Among them, solar energy is particularly prominent, being inexhaustible and having no impact on the environment. Its applied research has received more and more attention.

[0003] Since Japanese scientists T. Miyasaka et al. first prepared perovskite solar cells in 2009, they have received extensive attention from researchers. Its photoelectric conversion efficiency has developed from the initial 3.8% to the current 25.8%, which shows its huge development potential. In the process of preparing perovskite solar cells, the perovskite thin film has a greater impact on the device performance. During the preparation process, the crystallization rate is relatively fast and there are many defects, which will affect the carrier transport efficiency and hinder its photoelectric conversion efficiency. And due to the nature of perovskite itself, it is extremely vulnerable to external factors such as water and oxygen, thus reducing the stability of the device. A good way to solve this problem is to use additives during the preparation of the perovskite precursor solution, and utilize the reaction between the additives and the perovskite material to reduce various defects and improve the photoelectric conversion efficiency and device stability.

[0004] Most of the current passivation materials are insulating polymers, which will hinder the extraction of photo-generated carriers by the perovskite light-absorbing layer. And most of these materials have only a single functional group acting on perovskite, passivating one or two types of defects, and the lack of hydrophobic groups causes the perovskite device to be easily affected by water in the air, reducing the service life of the device. Summary of the Invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a preparation method of an efficient and stable perovskite solar cell. The technical problems to be solved by the present invention are realized through the following technical solutions:

[0006] The present invention provides a preparation method of a perovskite thin film, comprising:

[0007] Step 1: Prepare a perovskite precursor solution;

[0008] Step 2: Add a passivation defect additive to the prepared perovskite precursor solution;

[0009] Step 3: Using the solution spin-coating method, a perovskite thin film is prepared on a substrate from a perovskite precursor solution added with a passivation defect additive;

[0010] Among them, the small molecule structure of the passivation defect additive includes a carbonyl group, an amino group, a benzene ring, and a fluorine group.

[0011] In an embodiment of the present invention, the perovskite precursor solution is a precursor solution of an ABX3-type perovskite material, where A is at least one of Cs, MA, and FA, B is Pb and / or Sn, and X is at least one of Cl, Br, and I.

[0012] In an embodiment of the present invention, the passivation defect additive is 3,4-difluorobenzamide or 2,4-difluorobenzamide.

[0013] In an embodiment of the present invention, the addition amount of the passivation defect additive and the molar ratio of the perovskite precursor solution is 0.1% - 1.2%.

[0014] In an embodiment of the present invention, the step 3 includes:

[0015] Step 3.1: Using a spin coater, the perovskite precursor solution added with a passivation defect additive is spin-coated on a substrate by the solution spin-coating method to prepare a perovskite wet film;

[0016] Step 3.2: Annealing the perovskite wet film to obtain the perovskite thin film.

[0017] In an embodiment of the present invention, in the step 3.1, the spin-coating process parameters are: rotation speed 3500 r / min, acceleration 3000 r / min, and spin-coating time 15 - 50 s.

[0018] In an embodiment of the present invention, in the step 3.2, the annealing process parameters are: annealing time 10 - 30 min, and annealing temperature 100°C - 450°C.

[0019] The present invention provides an application of a perovskite thin film prepared by the method described in any one of the above embodiments in a solar cell.

[0020] The present invention provides a perovskite solar cell, including a substrate, a cathode, an electron transport layer, a perovskite light-absorbing layer, a hole transport layer, and an anode stacked in sequence from bottom to top, and the perovskite light-absorbing layer includes a perovskite thin film prepared by the method described in any one of the above embodiments.

[0021] The present invention provides a preparation method of a perovskite solar cell, including:

[0022] S1: Use the deionized aqueous solution of Decon-90, alcohol, and deionized water in sequence to clean the ITO-coated substrate wafer in an ultrasonic cleaner for 15 min. After drying with a nitrogen gun, place it in an ultraviolet ozone for pretreatment.

[0023] S2: Spin-coat the prepared SnO2 or TiO2 precursor solution on the pretreated ITO substrate wafer, and place it on a heating stage for annealing at 100 °C to 450 °C for 10 to 30 min to form an electron transport layer.

[0024] S3: Add the passivation defect additive to the prepared perovskite precursor solution. Using the solution spin-coating method, spin-coat the perovskite precursor solution with the passivation defect additive on the electron transport layer to obtain a perovskite wet film, and then place the prepared substrate on a heating stage for annealing treatment to form a perovskite light-absorbing layer; among them,

[0025] The spin-coating process parameters are: rotation speed 3500 r / min, acceleration 3000 r / min, spin-coating time 15 to 50 s; the annealing treatment process parameters are: annealing time 10 to 30 min, annealing temperature 100 °C to 450 °C.

[0026] S4: Deposit a hole transport layer on the perovskite light-absorbing layer.

[0027] S5: Use a vacuum coater to evaporate the metal anode of the solar cell on the hole transport layer to obtain a perovskite solar cell.

[0028] Among them, the small molecule structure of the passivation defect additive includes a carbonyl group, an amino group, a benzene ring, and a fluorine group;

[0029] The perovskite precursor solution is a precursor solution of an ABX3-type perovskite material, where A is at least one of Cs, MA, and FA, B is Pb and / or Sn, and X is at least one of Cl, Br, and I.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] 1. In the preparation method of the perovskite thin film of the present invention, a passivation defect additive is added to the perovskite precursor solution. The small molecule structure of the passivation defect additive includes a carbonyl group, an amino group, a benzene ring, and a fluorine group. Among them, the carbonyl group can bind to the Pb 2+ ions with insufficient coordination in the perovskite solution, or bind to other defective state cations to form a Lewis complex, thereby passivating the film defects. The fluorine group in the molecule has strong hydrophobicity, which can improve the stability of the perovskite solar device and is an effective charge transport channel between the perovskite light-absorbing layer and the hole transport layer. And the amino group among them improves C=O and Pb 2+Its coordination ability reduces the defects on the grain surface, improves the perovskite film formation quality, and the combination of amino groups and iodides can inhibit ion migration, further enhancing the passivation effect.

[0032] 2. In the method for preparing a perovskite solar cell of the present invention, during the preparation process of the perovskite light-absorbing layer, the comprehensive action of various functional groups in the passivation defect additive material can passivate defects more efficiently, thereby significantly improving the photoelectric conversion efficiency and stability of the solar cell.

[0033] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable, the following specifically gives preferred embodiments and, in conjunction with the drawings, details are described as follows. Brief Description of the Drawings

[0034] Figure 1 is a schematic diagram of a method for preparing a perovskite film provided by an embodiment of the present invention;

[0035] Figure 2 is a molecular structure diagram of a passivation defect additive material provided by an embodiment of the present invention;

[0036] Figure 3 is a schematic diagram of the structure of a perovskite solar cell provided by an embodiment of the present invention;

[0037] Figure 4 is a preparation flow chart of a perovskite solar cell provided by an embodiment of the present invention. Detailed Embodiments

[0038] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following, in conjunction with the drawings and specific embodiments, details a method for preparing a highly efficient and stable perovskite solar cell according to the present invention.

[0039] The foregoing and other technical contents, features and effects of the present invention can be clearly presented in the following detailed description in conjunction with the drawings. Through the description of the specific embodiments, a more in-depth and specific understanding of the technical means and effects adopted by the present invention to achieve the predetermined purpose can be obtained. However, the attached drawings are only for reference and explanation, and are not used to limit the technical solution of the present invention.

[0040] Embodiment

[0041] Please refer to Figure 1 , Figure 1 which is a schematic diagram of a method for preparing a perovskite film provided by an embodiment of the present invention. As shown in the figure, the method for preparing a perovskite film in this embodiment includes:

[0042] Step 1: Prepare a perovskite precursor solution;

[0043] In this embodiment, the perovskite precursor solution is a precursor solution of an ABX3-type perovskite material, where A is at least one of Cs, MA, and FA, B is Pb and / or Sn, and X is at least one of Cl, Br, and I.

[0044] Optionally, the perovskite precursor solution may be a precursor solution of MAPbI3, a precursor solution of MAPbBr3, a precursor solution of MAPbCl3, MAPbI 3-x Br x , where x = 0 - 3, a precursor solution, MAPbI 3-x Cl x , where x = 0 - 3, a precursor solution, FA y MA 1-y PbI 3-x Cl x , where x = 0 - 3, y = 0 - 1, a precursor solution, or FA y MA 1-y PbI 3-x Br x , where x = 0 - 3, y = 0 - 1, a precursor solution.

[0045] Specifically, the precursor materials of the perovskite film are dissolved in an organic solvent in the required stoichiometry to obtain the corresponding precursor solution, and the organic solvent is DMF, IPA, NMP, or a mixture thereof.

[0046] Step 2: Add a passivation defect additive to the prepared perovskite precursor solution;

[0047] Among them, the small molecule structure of the passivation defect additive includes a carbonyl group, an amino group, a benzene ring, and a fluorine group.

[0048] Optionally, the passivation defect additive is 3,4-difluorobenzamide or 2,4-difluorobenzamide. As Figure 2 shown in the molecular structure diagrams of the materials of the passivation defect additive, where (a) is 3,4-difluorobenzamide and (b) is 2,4-difluorobenzamide.

[0049] In this embodiment, the addition amount of the passivation defect additive and the perovskite precursor solution is in a molar ratio of 0.1% - 1.2%.

[0050] Step 3: Use the solution spin-coating method to prepare a perovskite thin film on a substrate from the perovskite precursor solution added with the passivation defect additive;

[0051] Specifically, Step 3 includes:

[0052] Step 3.1: Using a spin coater, a perovskite precursor solution added with a passivation defect additive is spin-coated on a substrate by solution spin coating method to prepare a perovskite wet film;

[0053] Specifically, the spin coating process parameters are: rotation speed 3500 r / min, acceleration 3000 r / min, and spin coating time 15 - 50 s.

[0054] Optionally, the substrate is glass.

[0055] Step 3.2: Anneal the perovskite wet film to obtain a perovskite thin film.

[0056] Specifically, the annealing process parameters are: annealing time 10 - 30 min, and annealing temperature 100 °C - 450 °C.

[0057] In the preparation method of the perovskite thin film of this embodiment, a passivation defect additive is added to the perovskite precursor solution. The small molecule structure of the passivation defect additive includes a carbonyl group, an amino group, a benzene ring, and a fluorine group. The carbonyl group in the passivation defect additive material can bind to the Pb 2+ ions with insufficient coordination in the perovskite solution, or bind to other defect state cations to form a Lewis complex, thereby passivating the film defects. The fluorine group has strong hydrophobicity, which can improve the stability of the perovskite solar device and is an effective charge transfer channel between the perovskite light absorption layer and the hole transport layer. The amino group improves the coordination ability of C=O and Pb 2+ , reduces the defects on the grain surface, improves the perovskite film formation quality, and the combination of the amino group and iodide can inhibit ion migration, further enhancing the passivation effect.

[0058] Furthermore, this embodiment also provides a perovskite solar cell. Please refer to Figure 3 , Figure 3 which is a schematic structural diagram of the perovskite solar cell provided by the embodiment of the present invention. As shown in the figure, the perovskite solar cell includes a substrate 1, a cathode 2, an electron transport layer 3, a perovskite light absorption layer 4, a hole transport layer 5, and an anode 6 stacked in sequence from bottom to top.

[0059] In this embodiment, the substrate 1 is any one of glass and quartz, and its function is to enable incident light to enter the device. Optionally, the thickness of the substrate 1 is 1.9 mm. The cathode 2 is an ITO substrate, and its function is to collect the electrons excited by the perovskite light absorption layer. The electron transport layer 3 is an SnO2 or TiO2 electron transport layer, which can effectively transport electrons and block holes.

[0060] Further, the perovskite light-absorbing layer 4 is a perovskite thin film, and the material of the perovskite thin film is an ABX3-type perovskite material, where A is at least one of Cs, MA, and FA, B is Pb and / or Sn, and X is at least one of Cl, Br, and I.

[0061] Optionally, the material of the perovskite thin film can be MAPbI3, MAPbBr3, MAPbCl3, MAPbI 3-x Br x 、MAPbI 3-x Cl x 、FA y MA 1-y PbI 3-x Cl x 、or FA y MA 1-y PbI 3-x Br x ,and the perovskite thin film is prepared by the method described in the above embodiment. The perovskite light-absorbing layer 4 can absorb incident light and convert light energy into electrical energy. Optionally, the thickness of the perovskite light-absorbing layer 4 is 180 - 310 nm.

[0062] Further, the hole transport layer 5 uses a Spiro-OMeTAD hole transport material. The hole transport layer 5 can extract effective charges and block electrons; the anode 6 is any one of silver, aluminum, magnesium, copper, and gold with a thickness of 60 - 200 nm, and the anode 6 is used to collect holes.

[0063] This embodiment also provides a preparation method of a perovskite solar cell, and the preparation method includes the following steps:

[0064] S1: Sequentially use deionized aqueous solution of Decon-90, alcohol, and deionized water to clean the ITO-coated substrate wafer with an ultrasonic cleaner for 15 min. After drying with a nitrogen gun, place it in ultraviolet ozone for pretreatment;

[0065] S2: Spin-coat the prepared SnO2 or TiO2 precursor solution on the pretreated ITO substrate wafer, and place it on a heating stage for annealing at 100 °C - 450 °C for 10 - 30 min to form an electron transport layer;

[0066] S3: Add a passivation defect additive to the prepared perovskite precursor solution. Using the solution spin-coating method, spin-coat the perovskite precursor solution added with the passivation defect additive on the electron transport layer to obtain a perovskite wet film, and then place the prepared substrate on a heating stage for annealing treatment to form a perovskite light-absorbing layer; where

[0067] The spin-coating process parameters are as follows: the rotation speed is 3500 r / min, the acceleration is 3000 r / min, and the spin-coating time is 15 - 50 s; the annealing treatment process parameters are as follows: the annealing time is 10 - 30 min, and the annealing temperature is 100°C - 450°C;

[0068] S4: Deposit a hole transport layer on the perovskite light-absorbing layer;

[0069] S5: Evaporate the metal anode of the solar cell on the hole transport layer using a vacuum coater to obtain a perovskite solar cell.

[0070] In this embodiment, the small molecule structure of the defect passivation additive includes a carbonyl group, an amino group, a benzene ring, and a fluorine group. Optionally, the defect passivation additive is 3,4-difluorobenzamide or 2,4-difluorobenzamide. The addition amount of the defect passivation additive to the perovskite precursor solution is 0.1% - 1.2% in molar ratio.

[0071] In this embodiment, the perovskite precursor solution is a precursor solution of an ABX3-type perovskite material, where A is at least one of Cs, MA, and FA, B is Pb and / or Sn, and X is at least one of Cl, Br, and I.

[0072] Optionally, the perovskite precursor solution can be a precursor solution of MAPbI3, a precursor solution of MAPbBr3, a precursor solution of MAPbCl3, a precursor solution of MAPbI 3-x Br x , where x = 0 - 3, a precursor solution of MAPbI 3-x Cl x , where x = 0 - 3, a precursor solution of FA y MA 1-y PbI 3-x Cl x , where x = 0 - 3, y = 0 - 1, a precursor solution, or a precursor solution of FA y MA 1-y PbI 3-x Br x , where x = 0 - 3, y = 0 - 1.

[0073] In the method for preparing a perovskite solar cell according to this embodiment, during the preparation process of the perovskite light-absorbing layer, the combined action of various functional groups in the defect passivation additive material can passivate defects more efficiently, thereby significantly improving the photoelectric conversion efficiency and stability of the solar cell.

[0074] Further, please refer to Figure 4 , Figure 4 which is the preparation flow chart of the perovskite solar cell provided by the embodiment of the present invention. The effects of the prepared perovskite solar cell are described in combination with specific embodiments.

[0075] Example 1

[0076] MAPbI3 perovskite solar cells were prepared with 3,4-difluorobenzamide additive at a molar ratio of 0.1%.

[0077] Step 1: Clean the ITO / glass substrate.

[0078] Pour an appropriate amount of deionized water, add a small amount of Decon-90, and ultrasonically clean the ITO-coated glass substrate for 15 min; then ultrasonically clean the substrate with alcohol and deionized water for 15 min in sequence. After cleaning, dry it with a nitrogen gun, and then pretreat it in ozone (UV-Ozone) for 30 min.

[0079] Step 2: Deposit the TiO2 electron transport layer on the pretreated substrate.

[0080] 2a) Prepare the TiO2 precursor solution;

[0081] Use a pipette gun to suck 550 μL of TiCl4 into a beaker, then add deionized water to the scale of 200 mL, and stir and mix the two evenly.

[0082] 2b) Spin-coat the TiO2 precursor solution;

[0083] Put the cleaned ITO / glass substrate into the prepared TiO2 precursor solution, seal the cup mouth, put it into an oven, and bake it at 70 °C for 30 min. After taking out the substrate, clean it with deionized water, then dry the moisture on the back, put it on a spin coater, with a rotation speed of 3000 r / min and a spin-coating time of 30 s, and then anneal it on a heating table at a temperature of 100 °C for 30 min.

[0084] Step 3: Prepare the MAPbI3 perovskite light-absorbing layer.

[0085] 3a) Prepare the precursor solution of MAPbI3 perovskite;

[0086] Weigh 1033 mg of MAI and 2996 mg of PbI2 respectively and dissolve them in 5 mL of a mixed solution of DMSO and GBL with a volume ratio of 3:7 to obtain a perovskite precursor solution. Then dissolve 3,4-difluorobenzamide additive with a molar ratio of 0.1% in the prepared perovskite precursor solution, and heat and stir it on a magnetic heating table at 75 °C for 1 h.

[0087] 3b) Spin-coat the MAPbI3 perovskite light-absorbing layer;

[0088] In a glove box filled with nitrogen, use a pipette to aspirate 75 μL of perovskite solution and evenly drop-coat it on the TiO2 electron transport layer. Set the rotation speed to 3500 r / min, the acceleration to 3000 r / min, and the time to 45 s. At 45 s, drop in 350 μL of toluene, and then place it on a heating stage for annealing. Set the temperature to 120 °C and the time to 30 min.

[0089] Step four, spin-coat the Spiro-OMeTAD hole transport layer on the annealed perovskite light-absorbing layer.

[0090] 4a) Prepare the precursor solution of Spiro-OMeTAD;

[0091] First, weigh 90 mg of Spiro powder and dissolve it in 1 mL of chlorobenzene solution in a glove box filled with nitrogen. Then, use a pipette to sequentially add 75 μL of cobalt salt solution, 45 μL of lithium salt solution, and 10 μL of TBP, and place it on a magnetic heating stirrer to stir until dissolved at room temperature.

[0092] 4b) Spin-coat the Spiro-OMeTAD solution;

[0093] Spin-coat the prepared precursor solution of Spiro-OMeTAD on the perovskite light-absorbing layer with a spin coater. Use a pipette to aspirate 75 μL of the solution and set the rotation mode to two-step spin coating. The rotation speed in the first step is 1000 r / min, the acceleration is 1000 r / min, and the time is 5 s. The rotation speed in the second step is 4000 r / min, the acceleration is 4000 r / min, and the time is 45 s.

[0094] Step five, prepare the top electrode.

[0095] Put the prepared substrate into a vacuum coating instrument to evaporate the Ag electrode. Among them, the vacuum degree is 1×10 -5 Pa, the current is 50 A, and the preparation of the MAPbI3 perovskite solar cell is completed, denoted as A1.

[0096] Step six, device testing and characterization.

[0097] Perform a photoelectric response test on the prepared perovskite solar cell A1 under the AM 1.5G solar spectrum.

[0098] Test results: The effective area is 7 mm 2 2, the energy conversion efficiency reaches 23.9%, the open-circuit voltage is 1.20 V, and the short-circuit current density is 25.6 mA / cm 2 2, and the fill factor is 77.8%.

[0099] Example 2

[0100] Prepare MAPbI3 perovskite solar cells with 3,4-difluorobenzamide additive at a molar ratio of 0.4%.

[0101] Step 1: Clean the ITO / glass substrate.

[0102] Pour an appropriate amount of deionized water, add a small amount of Decon-90, and ultrasonically clean the ITO-coated glass substrate for 15 min; then ultrasonically clean the substrate with alcohol and deionized water for 15 min in sequence. After cleaning, dry it with a nitrogen gun, and then pretreat it in ozone (UV-Ozone) for 30 min.

[0103] Step 2: Deposit the SnO2 electron transport layer on the pretreated substrate.

[0104] 2a) Prepare the SnO2 precursor solution;

[0105] Use a pipette to extract 2 mL of deionized water, and then use a pipette to extract 1 mL of SnO2 solution. Stir and mix the two evenly.

[0106] 2b) Spin-coat the SnO2 precursor solution;

[0107] Spin-coat the prepared SnO2 precursor solution on the cleaned ITO / glass substrate at a spin-coating speed of 3500 r / min for 30 s, and then anneal it on a heating table at 150 °C for 30 min to form a SnO2 electron transport layer with a thickness of 90 nm - 100 nm.

[0108] Step 3: Prepare the MAPbI3 perovskite light-absorbing layer.

[0109] 3a) Prepare the precursor solution of MAPbI3 perovskite;

[0110] Weigh 953 mg of CH3NH3I with an electronic balance and dissolve it in 5 mL of a mixed solvent with a volume ratio of dimethyl sulfoxide / γ-butyrolactone of 3:7. Place it on a magnetic stirring table and stir at room temperature until completely dissolved to obtain a 1.2 M / L CH3NH3I solution;

[0111] Then add 2212 mg of PbI2 to 4 mL of the above CH3NH3I solution, stir at 90 °C for 4 h until completely dissolved to obtain a 1.2 M / L CH3NH3PbI3 (MAPbI3) solution; then dissolve the 3,4-difluorobenzamide additive with a molar ratio of 0.4% in the prepared perovskite precursor solution, and place it on a magnetic heating table and heat and stir at 75 °C for 1 h.

[0112] 3b) Spin-coat the MAPbI3 perovskite light-absorbing layer;

[0113] In a nitrogen atmosphere, a perovskite precursor solution was spin-coated on the SnO2 electron transport layer at a rotation speed of 5000 r / min for 60 s, and then annealed on a hot plate at 100 °C for 10 min to obtain the MAPbI3 perovskite light-absorbing layer.

[0114] Step four, spin-coat the Spiro-OMeTAD hole transport layer on the annealed perovskite light-absorbing layer.

[0115] 4a) Prepare the precursor solution of Spiro-OMeTAD;

[0116] First, weigh 90 mg of Spiro powder, dissolve it in 1 mL of chlorobenzene solution in a glove box filled with nitrogen, and then sequentially add 75 μL of cobalt salt solution, 45 μL of lithium salt solution, and 10 μL of TBP using a pipette gun. Place it on a magnetic heating stirrer and stir at room temperature until dissolved.

[0117] 4b) Spin-coat the Spiro-OMeTAD solution;

[0118] The prepared precursor solution of Spiro-OMeTAD was spin-coated on the perovskite light-absorbing layer using a spin coater. Use a pipette gun to aspirate 75 μL of the solution, and set the rotation mode to two-step spin coating. The rotation speed in the first step is 1000 r / min, the acceleration is 1000 r / min, and the time is 5 s. The rotation speed in the second step is 4000 r / min, the acceleration is 4000 r / min, and the time is 45 s.

[0119] Step five, prepare the top electrode.

[0120] The prepared substrate was placed in a vacuum coating instrument to evaporate the Ag electrode, and the preparation of the MAPbI3 perovskite solar cell was completed, denoted as A2.

[0121] Step six, device testing and characterization.

[0122] The prepared perovskite solar cell A2 was subjected to a photoelectric response test under the AM 1.5G solar spectrum.

[0123] Test results: The effective area is 7 mm 2 , the energy conversion efficiency reaches 24.9%, the open-circuit voltage is 1.22 V, and the short-circuit current density is 25.6 mA / cm 2 , and the fill factor is 79.8%.

[0124] Example 3

[0125] Prepare MAPbI with 3,4-difluorobenzamide additive at a molar ratio of 0.8% 3-x Cl x, x = 0.5 perovskite solar cell.

[0126] Step 1: Clean the ITO / glass substrate.

[0127] Pour an appropriate amount of deionized water, add a small amount of Decon-90, and ultrasonically clean the ITO-coated glass substrate for 15 min; then ultrasonically clean the substrate with alcohol and deionized water for 15 min in sequence. After cleaning, dry it with a nitrogen gun and then pre-treat it in ozone (UV-Ozone) for 30 min.

[0128] Step 2: Deposit the SnO2 electron transport layer on the pre-treated substrate.

[0129] 2a) Prepare the SnO2 precursor solution;

[0130] Use a pipette to extract 2 mL of deionized water, and then use a pipette to extract 1 mL of SnO2 solution. Stir and mix the two evenly.

[0131] 2b) Spin-coat the SnO2 precursor solution;

[0132] Spin-coat the prepared SnO2 precursor solution on the cleaned ITO / glass substrate at a spinning speed of 3500 r / min for 30 s, and then anneal it on a heating table at 150 °C for 30 min to form a SnO2 electron transport layer with a thickness of 90 nm to 100 nm.

[0133] Step 3: Prepare the MAPbI 3-x Cl x perovskite light-absorbing layer.

[0134] 3a) Prepare the MAPbI 3-x Cl x precursor solution of perovskite;

[0135] Weigh 1072 mg of MAI, 2904 mg of PbI2, and 194.7 mg of PbCl2 with an electronic balance and dissolve them in 5 mL of a mixed solvent with a volume ratio of dimethyl sulfoxide / γ-butyrolactone of 3:7. Heat and stir the obtained solution at 70 °C until completely dissolved to obtain a 1.35 mol / L MAPbI 3-x Cl x solution. Then dissolve the additive of 3,4-difluorobenzamide with a molar ratio of 0.8% in the prepared perovskite precursor solution, and heat and stir it on a magnetic heating table at 75 °C for 1 h.

[0136] 3b) Spin-coat the MAPbI 3-x Cl x perovskite light-absorbing layer;

[0137] MAPbI was spin-coated on the SnO2 electron transport layer in a nitrogen-filled glove box. 3-x Cl x The solution was first spin-coated at a speed of 1500 r / min for 15 s, then the speed was increased to 4500 r / min for another 45 s. When the total spin-coating time was 40 s, 310 μL of toluene was quickly dripped in. Finally, the prepared substrate was placed on a hot plate at a temperature of 100 °C for annealing for 15 min to form a MAPbI with a thickness of 200 nm. 3-x Cl x Perovskite light-absorbing layer.

[0138] Step 4: Deposit NiO on the annealed perovskite light absorbing layer x Hole transport layer.

[0139] 4a) Preparation of NiO x Precursor solution;

[0140] First, weigh 270.79 mg of Ni(NO3)2·6H2O and dissolve it in 10 mL of 2-methoxyethanol solution. Then place the solution on a heating table, set the temperature to 50°C, and stir for 1 h. After 1 h, add 100 μL of acetylacetone solution, and then further stir at room temperature for 12 h.

[0141] 4b) Spin coating NiO x Precursor solution;

[0142] The prepared NiO x The precursor solution was spin-coated on the perovskite light-absorbing layer using a spin coater. 75 μL of the solution was aspirated using a pipette. The spin-coating speed was 4000 r / min and the spin-coating time was 45 s.

[0143] Step five: prepare the top electrode.

[0144] The prepared substrate was placed in a vacuum coating apparatus to evaporate the Ag electrode to complete the MAPbI 3-x Cl x Preparation of perovskite solar cells, denoted as A3.

[0145] Step six: device testing and characterization.

[0146] The prepared perovskite solar cell A3 was tested for photoelectric response under the AM 1.5G solar spectrum.

[0147] Test results: effective area is 7mm 2 , the energy conversion efficiency reached 23.4%, the open circuit voltage was 1.18V, and the short circuit current density was 25.2mA / cm 2 , the filling factor is 78.8%.

[0148] Example 4

[0149] Prepare MAPbI 3-x Cl x , x = 0.5 perovskite solar cell with 3,4-difluorobenzamide additive at a molar ratio of 1.2%.

[0150] Step 1: Clean the ITO / glass substrate.

[0151] Pour an appropriate amount of deionized water, add a small amount of Decon-90, and ultrasonically clean the ITO-coated glass substrate for 15 min; then ultrasonically clean the substrate with alcohol and deionized water for 15 min in sequence. After cleaning, dry it with a nitrogen gun, and then pre-treat it in ozone (UV-Ozone) for 30 min.

[0152] Step 2: Deposit the SnO2 electron transport layer on the pre-treated substrate.

[0153] 2a) Prepare the SnO2 precursor solution;

[0154] Use a pipette to extract 2 mL of deionized water, and then use a pipette to extract 1 mL of SnO2 solution. Stir and mix the two evenly.

[0155] 2b) Spin-coat the SnO2 precursor solution;

[0156] Spin-coat the prepared SnO2 precursor solution on the cleaned ITO / glass substrate at a spin-coating speed of 3500 r / min for 30 s, and then anneal it on a heating table at 150 °C for 30 min to form a SnO2 electron transport layer with a thickness of 90 nm to 100 nm.

[0157] Step 3: Prepare MAPbI 3-x Cl x perovskite light-absorbing layer.

[0158] 3a) Prepare the precursor solution of MAPbI 3-x Cl x perovskite;

[0159] Weigh 1072 mg of MAI, 2904 mg of PbI2, and 194.7 mg of PbCl2 with an electronic balance and dissolve them in 5 mL of a mixed solvent with a volume ratio of dimethyl sulfoxide / γ-butyrolactone of 3:7. Heat and stir the obtained solution at 70 °C until completely dissolved to obtain a 1.35 mol / L MAPbI 3-x Cl x solution. Then dissolve the 3,4-difluorobenzamide additive with a molar ratio of 1.2% in the prepared perovskite precursor solution, and heat and stir it on a magnetic heating table at 75 °C for 1 h.

[0160] 3b) Spin coating of MAPbI 3-x Cl x Perovskite light absorbing layer;

[0161] MAPbI was spin-coated on the SnO2 electron transport layer in a nitrogen-filled glove box. 3-x Cl x The solution was first spin-coated at a speed of 1500 r / min for 15 s, then the speed was increased to 4500 r / min for another 45 s. When the total spin-coating time was 40 s, 310 μL of toluene was quickly dripped in. Finally, the prepared substrate was placed on a hot plate at a temperature of 100 °C for annealing for 15 min to form a MAPbI with a thickness of 200 nm. 3-x Cl x Perovskite light-absorbing layer.

[0162] Step 4: Deposit NiO on the annealed perovskite light absorbing layer x Hole transport layer.

[0163] 4a) Preparation of NiO x Precursor solution;

[0164] First, weigh 270.79 mg of Ni(NO3)2·6H2O and dissolve it in 10 mL of 2-methoxyethanol solution. Then place the solution on a heating table, set the temperature to 50°C, and stir for 1 h. After 1 h, add 100 μL of acetylacetone solution, and then further stir at room temperature for 12 h.

[0165] 4b) Spin coating NiO x Precursor solution;

[0166] The prepared NiO x The precursor solution was spin-coated on the perovskite light-absorbing layer using a spin coater. 75 μL of the solution was aspirated using a pipette. The spin-coating speed was 4000 r / min and the spin-coating time was 45 s.

[0167] Step five: prepare the top electrode.

[0168] The prepared substrate was placed in a vacuum coating apparatus to evaporate the Ag electrode to complete the MAPbI 3-x Cl x Preparation of perovskite solar cell, denoted as A4.

[0169] Step six: device testing and characterization.

[0170] The prepared perovskite solar cell A4 was tested for photoelectric response under the AM 1.5G solar spectrum.

[0171] Test results: effective area is 7mm 2, the energy conversion efficiency reaches 23.6%, the open-circuit voltage is 1.19V, and the short-circuit current density is 25.1mA / cm 2 , and the fill factor is 78.9%.

[0172] Example 5

[0173] Prepare MAPbI with 2,4-difluorobenzamide additive at a molar ratio of 0.1% 3-x Cl x , x = 0.5 perovskite solar cell.

[0174] Step 1: Clean the ITO / glass substrate.

[0175] Pour an appropriate amount of deionized water, add a small amount of Decon-90, and ultrasonically clean the glass substrate coated with ITO for 15 minutes; then ultrasonically clean the substrate with alcohol and deionized water for 15 minutes in sequence. After cleaning, dry it with a nitrogen gun and then pretreat it in ozone (UV-Ozone) for 30 minutes.

[0176] Step 2: Deposit the SnO2 electron transport layer on the pretreated substrate.

[0177] 2a) Prepare the SnO2 precursor solution;

[0178] Use a pipette gun to extract 2 mL of deionized water, and then use a pipette gun to extract 1 mL of SnO2 solution. Stir and mix the two evenly.

[0179] 2b) Spin-coat the SnO2 precursor solution;

[0180] Spin-coat the prepared SnO2 precursor solution on the cleaned ITO / glass substrate at a spin-coating speed of 3500 r / min for 30 s, and then anneal it on a heating stage at 150 °C for 30 minutes to form a SnO2 electron transport layer with a thickness of 90 nm to 100 nm.

[0181] Step 3: Prepare MAPbI 3-x Cl x perovskite light-absorbing layer.

[0182] 3a) Prepare the precursor solution of MAPbI 3-x Cl x perovskite;

[0183] Weigh 1072 mg of MAI, 2904 mg of PbI2, and 194.7 mg of PbCl2 with an electronic balance and dissolve them in 5 mL of a mixed solvent with a volume ratio of dimethyl sulfoxide / γ-butyrolactone of 3:7. Heat and stir the obtained solution at 70 °C until completely dissolved to obtain 1.35 mol / L of MAPbI 3-x Clx Solution. Then, 2,4-difluorobenzamide additive with a molar ratio of 0.1% was dissolved in the prepared perovskite precursor solution, and the mixture was placed on a magnetic heating plate and heated with stirring at 75 °C for 1 h.

[0184] 3b) Spin-coat MAPbI 3-x Cl x perovskite light-absorbing layer;

[0185] Under a nitrogen-filled glove box, MAPbI 3-x Cl x solution was spin-coated on the SnO2 electron transport layer. First, it was spin-coated at a speed of 1500 r / min for 15 s, then the speed was increased to 4500 r / min and spin-coated for another 45 s. When the total spin-coating time reached 40 s, 310 μL of toluene was quickly dropped in; finally, the prepared substrate was placed on a hot plate at 100 °C and annealed for 15 min to form a MAPbI 3-x Cl x perovskite light-absorbing layer with a thickness of 200 nm.

[0186] Step Four, deposit NiO x hole transport layer on the annealed perovskite light-absorbing layer.

[0187] 4a) Prepare NiO x precursor solution;

[0188] First, 270.79 mg of Ni(NO3)2·6H2O was weighed and dissolved in 10 mL of 2-methoxyethanol solution. Then, the solution was placed on a heating plate with the temperature set at 50 °C and stirred for 1 h. After 1 h, 100 μL of acetylacetone solution was added, and then it was further stirred at room temperature for 12 h.

[0189] 4b) Spin-coat NiO x precursor solution;

[0190] The prepared NiO x precursor solution was spin-coated on the perovskite light-absorbing layer with a spin coater. 75 μL of the solution was aspirated with a pipette gun, and the spin-coating speed was 4000 r / min and the spin-coating time was 45 s.

[0191] Step Five, prepare the top electrode.

[0192] The prepared substrate was placed in a vacuum coater to evaporate the Ag electrode, completing the preparation of the MAPbI 3-x Cl x perovskite solar cell, denoted as A5.

[0193] Step Six, device testing and characterization.

[0194] The prepared perovskite solar cell A5 was subjected to a photoelectric response test under the AM 1.5G solar spectrum.

[0195] Test results: The effective area was 7 mm 2 , the energy conversion efficiency reached 24.1%, the open-circuit voltage was 1.19 V, and the short-circuit current density was 25.6 mA / cm 2 , and the fill factor was 79.1%.

[0196] Example 6

[0197] Prepare MAPbI with a 2,4-difluorobenzamide additive at a molar ratio of 1.2% 3-x Cl x , x = 0.5 perovskite solar cell.

[0198] Step 1: Clean the ITO / glass substrate.

[0199] Pour an appropriate amount of deionized water, add a small amount of Decon-90, and ultrasonically clean the glass substrate coated with ITO for 15 min; then ultrasonically clean the substrate with alcohol and deionized water for 15 min in sequence. After cleaning, dry it with a nitrogen gun and then pre-treat it in ozone (UV-Ozone) for 30 min.

[0200] Step 2: Deposit the SnO2 electron transport layer on the pre-treated substrate.

[0201] 2a) Prepare the SnO2 precursor solution;

[0202] Use a pipette to draw 2 mL of deionized water, and then use a pipette to draw 1 mL of SnO2 solution, and stir and mix the two evenly.

[0203] 2b) Spin-coat the SnO2 precursor solution;

[0204] Spin-coat the prepared SnO2 precursor solution on the cleaned ITO / glass substrate at a spin-coating speed of 3500 r / min for 30 s, and then anneal it on a heating table at 150 °C for 30 min to form a SnO2 electron transport layer with a thickness of 90 nm to 100 nm.

[0205] Step 3: Prepare MAPbI 3-x Cl x perovskite light-absorbing layer.

[0206] 3a) Prepare the precursor solution of MAPbI 3-x Cl x perovskite;

[0207] 1072 mg MAI, 2904 mg PbI2 and 194.7 mg PbCl2 were weighed with an electronic balance and dissolved in 5 mL of a mixed solvent of dimethyl sulfoxide / γ-butyrolactone with a volume ratio of 3:7. The resulting solution was heated and stirred at 70 °C until completely dissolved to obtain 1.35 mol / L MAPbI 3-x Cl x Then, 1.2% of 2,4-difluorobenzamide additive was dissolved in the prepared perovskite precursor solution, and the solution was heated and stirred at 75°C on a magnetic heating table for 1 h.

[0208] 3b) Spin coating of MAPbI 3-x Cl x Perovskite light absorbing layer;

[0209] MAPbI was spin-coated on the SnO2 electron transport layer in a nitrogen-filled glove box. 3-x Cl x The solution was first spin-coated at a speed of 1500 r / min for 15 s, then the speed was increased to 4500 r / min for another 45 s. When the total spin-coating time was 40 s, 310 μL of toluene was quickly dripped in. Finally, the prepared substrate was placed on a hot plate at a temperature of 100 °C for annealing for 15 min to form a MAPbI with a thickness of 200 nm. 3-x Cl x Perovskite light-absorbing layer.

[0210] Step 4: Deposit NiO on the annealed perovskite light absorbing layer x Hole transport layer.

[0211] 4a) Preparation of NiO x Precursor solution;

[0212] First, weigh 270.79 mg of Ni(NO3)2·6H2O and dissolve it in 10 mL of 2-methoxyethanol solution. Then place the solution on a heating table, set the temperature to 50°C, and stir for 1 h. After 1 h, add 100 μL of acetylacetone solution, and then further stir at room temperature for 12 h.

[0213] 4b) Spin coating NiO x Precursor solution;

[0214] The prepared NiO x The precursor solution was spin-coated on the perovskite light-absorbing layer using a spin coater. 75 μL of the solution was aspirated using a pipette. The spin-coating speed was 4000 r / min and the spin-coating time was 45 s.

[0215] Step five: prepare the top electrode.

[0216] Put the prepared substrate into a vacuum coating instrument to evaporate the Ag electrode, and complete the preparation of the MAPbI 3-x Cl x perovskite solar cell, denoted as A6.

[0217] Step six, device testing and characterization.

[0218] Perform a photoelectric response test on the prepared perovskite solar cell A6 under the AM 1.5G solar spectrum.

[0219] Test results: The effective area is 7mm 2 , the energy conversion efficiency reaches 24.4%, the open-circuit voltage is 1.20V, and the short-circuit current density is 25.7mA / cm 2 , and the fill factor is 79.2%.

[0220] Comparative example 1

[0221] Prepare MAPbI without additives 3-x Cl x , x = 0.5 perovskite solar cell.

[0222] Step one: Clean the ITO / glass substrate.

[0223] Pour an appropriate amount of deionized water, add a small amount of Decon-90, and ultrasonically clean the glass substrate coated with ITO for 15 minutes; then ultrasonically clean the substrate with alcohol and deionized water for 15 minutes in sequence. After cleaning, dry it with a nitrogen gun, and then pre-treat it in ozone (UV-Ozone) for 30 minutes.

[0224] Step two, deposit the SnO2 electron transport layer on the pre-treated substrate.

[0225] 2a) Prepare the SnO2 precursor solution;

[0226] Use a pipette to extract 2 mL of deionized water, and then use a pipette to extract 1 mL of SnO2 solution, and stir and mix the two evenly.

[0227] 2b) Spin-coat the SnO2 precursor solution;

[0228] Spin-coat the prepared SnO2 precursor solution on the cleaned ITO / glass substrate at a spin-coating speed of 3500 r / min for 30 s, and then anneal it on a heating table at 150 °C for 30 minutes to form a SnO2 electron transport layer with a thickness of 90 nm to 100 nm.

[0229] Step three, prepare MAPbI 3-x Cl x perovskite light-absorbing layer.

[0230] 3a) Preparation of MAPbI 3-x Cl x Titanite precursor solution;

[0231] 1072 mg MAI, 2904 mg PbI2 and 194.7 mg PbCl2 were weighed with an electronic balance and dissolved in 5 mL of a mixed solvent of dimethyl sulfoxide / γ-butyrolactone with a volume ratio of 3:7. The resulting solution was heated and stirred at 70 °C until completely dissolved to obtain 1.35 mol / L MAPbI 3-x Cl x The solution was placed on a magnetic heating table and heated at 75°C with stirring for 1 h.

[0232] 3b) Spin coating of MAPbI 3-x Cl x Perovskite light absorbing layer;

[0233] MAPbI was spin-coated on the SnO2 electron transport layer in a nitrogen-filled glove box. 3-x Cl x The solution was first spin-coated at a speed of 1500 r / min for 15 s, then the speed was increased to 4500 r / min for another 45 s. When the total spin-coating time was 40 s, 310 μL of toluene was quickly dripped in. Finally, the prepared substrate was placed on a hot plate at a temperature of 100 °C for annealing for 15 min to form a MAPbI with a thickness of 200 nm. 3-x Cl x Perovskite light-absorbing layer.

[0234] Step 4: Deposit NiO on the annealed perovskite light absorbing layer x Hole transport layer.

[0235] 4a) Preparation of NiO x Precursor solution;

[0236] First, weigh 270.79 mg of Ni(NO3)2·6H2O and dissolve it in 10 mL of 2-methoxyethanol solution. Then place the solution on a heating table, set the temperature to 50°C, and stir for 1 h. After 1 h, add 100 μL of acetylacetone solution, and then further stir at room temperature for 12 h.

[0237] 4b) Spin coating NiO x Precursor solution;

[0238] The prepared NiO x The precursor solution was spin-coated on the perovskite light-absorbing layer using a spin coater. 75 μL of the solution was aspirated using a pipette. The spin-coating speed was 4000 r / min and the spin-coating time was 45 s.

[0239] Step five: prepare the top electrode.

[0240] Put the prepared substrate into a vacuum coating instrument to evaporate the Ag electrode to complete the preparation of the MAPbI 3-x Cl x perovskite solar cell, denoted as A7.

[0241] Step six, device testing and characterization.

[0242] Perform a photoelectric response test on the prepared perovskite solar cell A7 under the AM 1.5G solar spectrum.

[0243] Test results: The effective area is 7 mm 2 , the energy conversion efficiency reaches 21.3%, the open circuit voltage is 1.17 V, and the short circuit current density is 23.5 mA / cm 2 , and the fill factor is 77.5%.

[0244] The test results of the above Examples 1-6 and Comparative Example 1 are shown in Table 1:

[0245] Table 1. Test Results

[0246]

[0247] As can be seen from Table 1, compared with Comparative Example 1 without adding any passivator, in other Examples 1-6, the defect passivators 3,4-difluorobenzamide or 2,4-difluorobenzamide were added to the perovskite precursor solution. The carbonyl group in the passivation defect additive material can bind to the Pb 2+ ions with insufficient coordination in the perovskite solution, or bind to other defective cations to form a Lewis complex, thereby passivating the film defects. The fluorine group is an effective charge transport channel between the perovskite light-absorbing layer and the hole transport layer. The amino group improves the coordination ability of C=O and Pb 2+ , reduces the defects on the grain surface, improves the perovskite film formation quality, and the combination of the amino group and iodide can inhibit ion migration, further enhancing the passivation effect. This leads to an increase in the short circuit current, open circuit voltage, and fill factor, ultimately greatly improving the conversion efficiency of the device.

[0248] It should be noted that in this article, the term "including", "comprising" or any other variant is intended to cover non-exclusive inclusion, so that an article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed. Without further limitations, an element defined by the statement "including one..." does not exclude the existence of another identical element in the article or device including the said element.

[0249] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, several simple deductions or substitutions can still be made, and all should be regarded as belonging to the protection scope of the present invention.

Claims

1. A method for preparing a perovskite thin film, characterized in that, Comprising: Step 1: Prepare a perovskite precursor solution; Step 2: Add a passivation defect additive to the prepared perovskite precursor solution; Step 3: Using the solution spin-coating method, spin-coat the perovskite precursor solution added with the passivation defect additive on a substrate to obtain a perovskite thin film; Wherein, the small molecule structure of the passivation defect additive includes a carbonyl group, an amino group, a benzene ring and a fluorine group, and the passivation defect additive is 3,4-difluorobenzamide or 2,4-difluorobenzamide.

2. The method for preparing a perovskite thin film according to claim 1, wherein The perovskite precursor solution is a precursor solution of an ABX3-type perovskite material, wherein A is at least one of Cs, MA, and FA, B is Pb and / or Sn, and X is at least one of Cl, Br, and I.

3. The preparation method of the perovskite thin film according to claim 1, characterized in that, The addition amount of the passivation defect additive and the molar ratio of the perovskite precursor solution are 0.1% - 1.2%.

4. The method for preparing a perovskite thin film according to claim 1, characterized in that, Said Step 3 includes: Step 3.1: Using a spin coater, spin-coat the perovskite precursor solution added with the passivation defect additive on a substrate by the solution spin-coating method to obtain a perovskite wet film; Step 3.2: Anneal the perovskite wet film to obtain the perovskite thin film.

5. The method for preparing a perovskite thin film according to claim 4, wherein In said Step 3.1, the spin-coating process parameters are: rotation speed 3500 r / min, acceleration 3000 r / min, and spin-coating time 15 - 50 s.

6. The method for preparing a perovskite thin film according to claim 4, wherein In said Step 3.2, the annealing process parameters are: annealing time 10 - 30 min, and annealing temperature 100°C - 450°C.

7. Application of the perovskite thin film prepared by the method according to any one of claims 1 to 6 in a solar cell.

8. A perovskite solar cell, comprising a substrate, a cathode, an electron transport layer, a perovskite light-absorbing layer, a hole transport layer, and an anode that are sequentially stacked from bottom to top, characterized in that, The perovskite light-absorbing layer includes the perovskite thin film prepared by the method according to any one of claims 1 to 6.

9. A preparation method of a perovskite solar cell, characterized in that, Comprising: S1: Sequentially use deionized aqueous solution of Decon-90, alcohol and deionized water to clean the ITO-coated substrate wafer in an ultrasonic cleaner for 15 min, dry it with a nitrogen gun and then place it in ultraviolet ozone for pretreatment; S2: Spin-coat the prepared SnO2 or TiO2 precursor solution on the pretreated ITO substrate wafer, and place it on a heating stage to anneal for 10 - 30 min at 100°C - 450°C to form an electron transport layer; S3: Add a passivation defect additive to the prepared perovskite precursor solution, and using the solution spin-coating method, spin-coat the perovskite precursor solution added with the passivation defect additive on the electron transport layer to obtain a perovskite wet film, and then place the prepared substrate on a heating stage for annealing treatment to form a perovskite light-absorbing layer; wherein, The spin-coating process parameters are: rotation speed 3500 r / min, acceleration 3000 r / min, and spin-coating time 15 - 50 s; the annealing process parameters are: annealing time 10 - 30 min, and annealing temperature 100°C - 450°C; S4: Deposit a hole transport layer on the perovskite light-absorbing layer; S5: Evaporate the metal anode of the solar cell on the hole transport layer using a vacuum coater to obtain a perovskite solar cell; Among them, the small molecule structure of the passivation defect additive includes a carbonyl group, an amino group, a benzene ring and a fluorine group, and the passivation defect additive is 3,4-difluorobenzamide or 2,4-difluorobenzamide; The perovskite precursor solution is a precursor solution of an ABX3-type perovskite material, where A is at least one of Cs, MA, and FA, B is Pb and / or Sn, and X is at least one of Cl, Br, and I.

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