Preparation method of formamidine perovskite active layer and perovskite solar cell thereof
By adding 3,5,5-trimethyl-2-cyclohexene-1-one additive in the preparation of the active layer of formamidine perovskite solar cells, the problems of unstable crystal phase and poor controllability of the crystallization process were solved, and efficient and stable photoelectric conversion effects were achieved.
Patent Information
- Application Number
- CN202511199193.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-26
- Publication Date
- 2025-10-14
AI Technical Summary
During the preparation of the active layer of formamidine perovskite solar cells, the crystal phase is unstable and easily transformed into a yellow phase with no photovoltaic activity. In addition, the crystallization process is poorly controllable, resulting in poor film morphology and high grain boundary defect density, which affects the photoelectric conversion efficiency and stability.
During the preparation of the formamidine perovskite active layer, 3,5,5-trimethyl-2-cyclohexene-1-one additive is added, and an antisolvent is dripped on the substrate by spin coating and annealed to form a high-quality formamidine perovskite active layer, reducing the generation of harmful intermediate phases and passivating grain boundaries.
The photoelectric conversion efficiency and stability of formamidinium perovskite solar cells were improved, and the performance of the device was enhanced by forming a more ordered crystal structure and reducing the defect state density.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of perovskite solar cells, and in particular relates to a method for preparing a formamidine perovskite active layer and a perovskite solar cell thereof. Background Art
[0002] Organic-inorganic hybrid perovskite solar cells, a novel green energy generation technology, have attracted widespread attention due to their high photoelectric conversion efficiency, large-area solution processing, and ability to be combined with silicon solar cells to create stacked solar cells. A research hotspot in solar power generation, perovskite solar cells have seen their photoelectric conversion efficiency increase from an initial 3.8% to 26.7% in just over a decade, demonstrating broad application prospects.
[0003] Formamidine perovskite solar cells are a type of perovskite solar cell with the greatest development potential due to their high photoelectric conversion efficiency and good thermal stability. However, during the preparation of the active layer of formamidine perovskite solar cells, the resulting crystalline phase is unstable, with its α phase easily transforming into a yellow phase that is photovoltaically inactive. This results in the inability to produce a photovoltaically active active layer film, and the resulting photovoltaic devices are unable to achieve photoelectric conversion or have extremely low photoelectric conversion efficiency. Furthermore, the currently widely used perovskite polycrystalline ionic crystal films are mostly prepared using solution processing techniques, which have poor controllability during the crystallization process and are prone to problems such as excessively fast crystallization rates. This results in poor film morphology and excessively high perovskite grain boundary defect state density, which increases non-radiative energy loss and affects the photoelectric conversion efficiency and stability of perovskite solar cell devices. Summary of the Invention
[0004] Therefore, the technical problem to be solved by the present invention is to overcome the above-mentioned defects in the prior art, thereby providing a method for preparing a formamidine perovskite active layer and a perovskite solar cell thereof.
[0005] To this end, the present invention provides the following technical solutions:
[0006] In the first aspect, the present application provides a method for preparing a formamidine perovskite active layer. When preparing the formamidine perovskite active layer, a 3,5,5-trimethyl-2-cyclohexene-1-one additive is added. The method for preparing the formamidine perovskite active layer is as follows: 3,5,5-trimethyl-2-cyclohexene-1-one, lead iodide, formamidine hydroiodide, and methylamine hydrochloride are dissolved in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide to prepare a formamidine perovskite precursor solution, the prepared formamidine perovskite precursor solution is dropped onto a substrate, an antisolvent is added onto the rotating substrate, and annealing is performed to obtain a formamidine perovskite active layer.
[0007] Optionally, the concentration of 3,5,5-trimethyl-2-cyclohexen-1-one in the formamidinium perovskite precursor solution is 0.1-5 mg / mL.
[0008] Optionally, the concentration of formamidinium perovskite components in the formamidinium perovskite precursor solution is 1.5-2.0 mmol / mL, and the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is 5:1-10:1.
[0009] Optionally, the anti-solvent is at least one selected from chlorobenzene, diethyl ether, acetone, toluene, ethyl acetate or chloroform.
[0010] Optionally, the rotation speed during preparation of the formamidinium perovskite active layer is 2000 rpm-8000 rpm, the rotation time is 30 s-80 s, and the anti-solvent is added at 5-40 s after the start of rotation.
[0011] Optionally, the anti-solvent is added at 10 s-50 s after the start of rotation during preparation of the formamidinium perovskite active layer.
[0012] Optionally, the rotation speed during preparation of the formamidinium perovskite active layer is 2000 rpm-8000 rpm, the rotation time is 30 s-80 s, and the anti-solvent is added at 5-40 s after the start of rotation.
[0013] Optionally, the annealing temperature during preparation of the formamidinium perovskite active layer is 100℃-180℃, the annealing time is 10 min-60 min, the annealing atmosphere is air environment, and the air humidity is 20%-50%.
[0014] Optionally, the thickness of the formamidinium perovskite active layer is 300 nm-1500 nm.
[0015] In a second aspect, the application provides a formamidinium perovskite solar cell, comprising a transparent conductive substrate layer, an electron transport layer, a formamidinium perovskite active layer prepared by the above method, a passivation layer, a hole transport layer and a metal back electrode arranged in sequence.
[0016] Specifically, the preparation method of the above formamidinium perovskite solar cell provided by the application can be as follows:
[0017] Step 1: Clean the FTO glass substrate with deionized water, acetone and isopropanol in sequence, and blow the solvent remaining on the glass substrate with a nitrogen stream to obtain a clean transparent conductive substrate;
[0018] Step 2: After the conductive substrate cleaned in step 1 is UVO treated, it is placed on a coater. A pipette is used to draw up the tin dioxide nanocrystal solution and evenly coat it on the surface of the substrate. The coater is started to rotate at high speed. After the rotation stops, the substrate is placed on a hot plate and annealed in air to obtain an electron transport layer.
[0019] Step 3: After UVO treatment, place the substrate prepared in step 2 on a spin coater in a glove box. Use a pipette to draw the prepared formamidine perovskite precursor solution and evenly apply it on the substrate surface. Start the spin coater to rotate at high speed, add anti-solvent, and after the rotation stops, place it on a hot plate in an air environment for annealing to obtain a formamidine perovskite active layer.
[0020] Step 4: Place the substrate from step 3 on a coater in a glove box, use a pipette to draw up the prepared passivation layer solution, and evenly apply it on the substrate surface. Start the coater to rotate at high speed. After the rotation stops, place the substrate on a hot plate in the glove box for annealing to obtain a passivation layer.
[0021] Step 5: Place the substrate from step 4 on a coater in the glove box, use a pipette to draw up the prepared hole transport layer solution, evenly apply it on the surface of the substrate, start the coater to rotate at high speed, and after the rotation stops, the hole transport layer is obtained;
[0022] Step 6: Prepare a metal back electrode on the hole transport layer by thermal evaporation on the substrate in step 5.
[0023] Furthermore, the ultrasonic cleaning time using each solvent in step 1 is 10 minutes to 30 minutes.
[0024] Furthermore, in step 2, the rotation speed of the coating machine is 3000 rpm to 8000 rpm, the rotation time is 15 s to 60 s, the hot plate annealing temperature is 100° C. to 180° C., and the annealing time is 15 min to 60 min.
[0025] Furthermore, in step 3, the volume of the formamidine perovskite precursor solution aspirated by a pipette for each substrate (2 cm×2 cm) is 20 μL to 100 μL.
[0026] Furthermore, in step 4, the hot stage annealing temperature is 80° C. to 180° C., and the annealing time is 5 min to 60 min.
[0027] Furthermore, in step 5, the volume of the hole transport layer solution aspirated by the pipette for each substrate (2 cm×2 cm) is 30 μL to 80 μL, the rotation speed of the gel spinner is 3000 rpm to 8000 rpm, and the rotation time is 30 s to 60 s.
[0028] Furthermore, during the evaporation in step 6, the pressure in the evaporation chamber is 9×10 -5Pa, the thickness of molybdenum oxide is 8nm, and the thickness of the metal Ag electrode is 80nm~120nm.
[0029] The technical solution of the present invention has the following advantages:
[0030] The present invention provides a method for preparing a formamidine perovskite active layer and a perovskite solar cell thereof. Compared with the prior art, the present invention adds a 3,5,5-trimethyl-2-cyclohexene-1-one additive when preparing the formamidine perovskite active layer. The present invention has the following beneficial technical effects: 3,5,5-trimethyl-2-cyclohexene-1-one contains functional groups such as carbonyl groups, which can interact with lead iodine octahedra in the solution during the phase formation process, reducing the generation of harmful intermediate phases, forming crystals with more ordered orientation, larger size, and better quality, and improving film formation quality. At the same time, after the phase formation is completed, the non-volatile additive components will be repelled to the grain boundaries, play a role in passivating the bulk phase grain boundaries, reducing the defect state density of the active layer, and thus improving the photoelectric conversion efficiency and stability of the formamidine perovskite solar cell device.
[0031] The preparation method of the formamidine perovskite solar cell provided by the present invention has simple process, mild conditions, easy control, and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0033] Figure 1 Schematic diagram of the structure of the formamidine perovskite solar cell provided by the present invention;
[0034] Figure 2 is a JV curve diagram of the formamidine perovskite solar cell provided in Examples 1-3 of the present invention;
[0035] Figure 3 1 is a JV curve diagram of the formamidine perovskite solar cell provided in Example 1 and Comparative Example 1 of the present invention;
[0036] Figure 4 3 is a graph showing the relationship between the normalized energy conversion efficiency of the formamidine perovskite solar cells provided in Examples 1-3 of the present invention and Comparative Example 1 and the change over time.
[0037] Reference numerals:
[0038] 1, transparent conductive substrate layer; 2, electron transport layer; 3, formamidinium perovskite active layer; 4, passivation layer; 5, hole transport layer; 6, metal back electrode. DETAILED DESCRIPTION
[0039] The following examples are provided to better further understand the present application, and are not limited to the best mode, and do not constitute limitations on the content and protection scope of the present application, and any person under the inspiration of the present application or the combination of the present application with other prior art features, any product same or similar to the present application falls within the protection scope of the present application.
[0040] The specific experimental steps or conditions not mentioned in the examples can be carried out according to the conventional experimental steps described in the literature or the operation or conditions. The reagents or instruments not marked by the manufacturer are conventional reagent products that can be obtained by market purchase.
[0041] The present application provides a kind of formamidinium perovskite active layer preparation method and perovskite solar cell thereof, when preparing formamidinium perovskite active layer, add 3,5,5-trimethyl-2-cyclohexene-1-ketone additive.The structure schematic diagram of perovskite solar cell provided by the present application is as shown in Figure 1 Including transparent conductive substrate layer 1, electron transport layer 2, formamidinium perovskite active layer 3, passivation layer 4, hole transport layer 5 and metal back electrode 6 arranged in sequence.
[0042] The preparation method of perovskite solar cell provided by the present application includes the following steps:
[0043] Form electron transport layer, formamidinium perovskite active layer, passivation layer, hole transport layer and metal back electrode on the surface of transparent conductive substrate in sequence to obtain formamidinium perovskite solar cell;
[0044] Among them, the preparation method of formamidinium perovskite active layer is: 3,5,5-trimethyl-2-cyclohexene-1-ketone, lead iodide, formamidinium hydroiodide, methylamine hydrochloride are dissolved in mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide, and the prepared solution is added dropwise on the substrate, anti-solvent is added dropwise on the rotating substrate, and annealing is carried out to obtain formamidinium perovskite active layer.
[0045] In the present application, the transparent conductive substrate is preferably ITO glass, FTO glass, AZO glass or conductive PET, and more preferably FTO glass. The present application does not have special limitations on the source of the transparent conductive substrate, and commercially available goods known to those skilled in the art can be used. In the present application, the transparent conductive substrate is preferably cleaned with deionized water, acetone and isopropanol respectively for 15-30 min before use, and dried with a nitrogen gun.
[0046] In the present application, the electron transport layer is preferably SnO2, TiO x , NiO x , CuO x , CuSCN, CuPc or C 60 and derivatives thereof, and more preferably SnO2. The thickness of the electron transport layer is preferably 10 nm to 200 m, and more preferably 20 nm to 100 nm. The present application does not have a special restriction on the method of forming the electron transport layer on the conductive substrate, and the preparation method of the electron transport layer known to those skilled in the art can be used.
[0047] In the present application, the perovskite precursor solution thin film structure is FAPbI3. The solvent of the perovskite precursor solution is preferably one or more of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), and more preferably the solvent of the perovskite precursor solution is a mixed solvent of DMF and DMSO with a volume ratio of DMF:DMSO = 7:1. The concentration of the perovskite precursor solution is preferably 1 mmol / mL to 2 mmol / mL, and more preferably the concentration of the perovskite precursor solution is 1.8 mmol / mL. On this basis, the perovskite precursor solution capable of forming the perovskite precursor solution thin film known to those skilled in the art can be used, and those skilled in the art do not have a special restriction on the preparation method of the perovskite precursor solution.
[0048] In the present application, the anti-solvent is preferably one or more of chlorobenzene, diethyl ether, acetone, toluene, ethyl acetate and chloroform, and more preferably chlorobenzene.
[0049] In the present application, the preparation method of the formamidinium perovskite active layer is preferably one-step spin coating, and the process is preferably as follows: after the substrate (2 cm x 2 cm) is treated by UVO for 10 min, it is placed on a spin coater in a glove box, 30 μL to 60 μL of the prepared formamidinium perovskite active layer precursor solution added with 3,5,5-trimethyl-2-cyclohexen-1-one is sucked by a pipette, and is uniformly coated on the surface of the substrate. The spin coater is started at a high speed with a rotation speed of 3000 rpm to 6000 rpm and a rotation time of 30 to 60 s. At the 25th to 40th second after the start of rotation, 300 μL to 2000 μL of anti-solvent is added dropwise. After the rotation stops, the substrate is placed on a hot stage for annealing in an air environment. The annealing temperature is 100 ℃ to 150 ℃, the annealing time is 10 min to 30 min, and the air humidity is 30% to 40%. After the annealing is completed, the formamidinium perovskite active layer is obtained.
[0050] In the present application, the thickness of the formamidinium perovskite active layer is preferably 100 nm to 2000 nm, and more preferably 300 nm to 1500 nm.
[0051] In the present invention, the hole transport layer is preferably Spiro-OMeTAD, P3HT, PTAA, MnO x , WO x or 2PACz layer, more preferably a Spiro-OMeTAD layer; the thickness of the hole transport layer is preferably 20 nm to 400 nm, more preferably 100 nm to 200 nm. The present invention has no particular limitation on the method for forming the hole transport layer on the formamidine perovskite active layer, and methods for preparing hole transport layers well known to those skilled in the art can be used.
[0052] The present invention has no particular restrictions on the type and formation of the counter electrode. A technical solution for forming the counter electrode on the hole transport layer that is well known to those skilled in the art can be used. In a preferred embodiment of the present invention, the substrate after the hole transport layer is prepared is transferred to a thermal evaporation device, and the vacuum degree reaches 9×10 -5 Under the conditions of Pa, molybdenum oxide was evaporated to a thickness of 8 nm, and then an electrode (Ag) was evaporated to a thickness of 100 nm. After the evaporation was completed, a formamidinium perovskite solar cell was obtained.
[0053] The present invention provides a method for preparing a formamidine perovskite active layer and a perovskite solar cell thereof. The method comprises the following steps: dissolving 3,5,5-trimethyl-2-cyclohexene-1-one, lead iodide, formamidine hydroiodide, and methylamine hydrochloride in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide; dripping the prepared solution onto a substrate; adding an antisolvent onto the rotating substrate; and annealing to obtain a formamidine perovskite active layer. An electron transport layer, a formamidine perovskite active layer, a passivation layer, a hole transport layer, and a metal back electrode are sequentially formed on the surface of a transparent conductive substrate to obtain a formamidine perovskite solar cell. Compared with existing methods, the present invention has the following advantageous technical effects: 3,5,5-trimethyl-2-cyclohexene-1-one contains functional groups such as carbonyl groups, which can interact with lead iodine octahedra in the solution during phase formation, reducing the formation of harmful intermediate phases and forming crystals with more ordered orientation, larger size, and higher quality, thereby improving film quality. At the same time, after the non-volatile additive components have formed, they are repelled to the grain boundaries, passivating the bulk phase grain boundaries and reducing the defect state density of the active layer, thereby improving the photoelectric conversion efficiency and stability of the formamidine perovskite solar cell device. Furthermore, the preparation method provided by the present invention is simple, operates under mild and easily controllable conditions, and has broad application prospects.
[0054] In order to further illustrate the present invention, the following examples are given below to provide a detailed description.
[0055] Example 1
[0056] This embodiment provides a formamidine perovskite solar cell, the composition and specific preparation method of which are as follows:
[0057] Step 1: Place the FTO transparent conductive glass substrate (2 cm × 2 cm) in deionized water, acetone, and isopropanol and ultrasonically clean it for 15 min each twice, blow dry it with nitrogen, and store it for later use.
[0058] Step 2: Dilute the tin dioxide (SnO2) stock solution with ultrapure water in a volume ratio of 1:5, and stir thoroughly to obtain a SnO2 precursor solution; place the FTO substrate in a UV ozone cleaner for 15 minutes; take 50 μL of SnO2 precursor solution and evenly spread it on the surface of the FTO conductive glass, and set the parameters of the coating machine to a speed of 3000 rpm / s and a time of 30 seconds; then place it on a 150°C hot plate in an air environment for annealing for 30 minutes to obtain a SnO2 film (30 nm); place the SnO2 film prepared above in a UV ozone cleaner for 15 minutes for subsequent spin coating.
[0059] Step 3:. The substrate was placed on a coater in a glove box, and 50 μL of the prepared formamidine perovskite solution (3,5,5-trimethyl-2-cyclohexen-1-one, PbI2, FAI, and MACl were dissolved in a mixed solvent of DMF and DMSO, with a molar ratio of PbI2:FAI:MACl=3:3:1, a volume ratio of DMF:DMSO=7:1, a FAPbI3 concentration of 1.8 mol / L, and a 3,5,5-trimethyl-2-cyclohexen-1-one concentration of 1.0 mg / mL) was evenly coated on the surface of the substrate. The coater was started to rotate at high speed, with a rotation speed of 5000 rpm and a rotation time of 60 s. 200 μL of chlorobenzene antisolvent was added dropwise 30 s after the rotation started. After the rotation stopped, the solution was placed on a hot stage for annealing in air at a temperature of 120°C, a time of 60 min, and an air humidity of 40%. After annealing, a formamidine perovskite active layer (400 nm) was obtained.
[0060] Step 4: Place the substrate on a coater in the glove box, use a pipette to draw 50 μL of the prepared phenylethylammonium iodide (PEAI) solution (solvent is isopropanol, concentration 2.0 mg / mL), and evenly apply it on the surface of the substrate. Start the coater to rotate at high speed, with a rotation speed of 5000 rpm and a rotation time of 30 s. After the rotation stops, place it on the hot stage in the glove box for annealing at an annealing temperature of 100°C and an annealing time of 10 min. After annealing is completed, a passivation layer is obtained.
[0061] Step 5: Take 60 μL of Spiro-OMeTAD solution (90 mg of spiro-OMeTAD, 21 μL of LiTFSI solution (520 mg of Li-TFSI is dissolved in 1 mL of acetonitrile), 39 μL of 4-tert-butylpyridine, and 15 μL of Co(Ⅲ)TFSI (300 mg of Co(Ⅲ)TFSI is dissolved in 1 mL of acetonitrile) and dissolved in 1 mL of chlorobenzene solvent) and spin coat it on the prepared formamidine perovskite film. The parameters of the spin coater are set to a speed of 5000 rpm / s and a time of 30 s to obtain a hole transport layer.
[0062] Step 5: Finally, use high vacuum evaporation equipment to evaporate, and the pressure in the evaporation chamber is 9×10 -5 Pa, first evaporate 8nm thick molybdenum oxide, and then evaporate 100nm thick metal Ag electrode to obtain formamidinium perovskite solar cell device.
[0063] Example 2
[0064] This embodiment provides a formamidine perovskite solar cell. Compared with Example 1, the difference is that the concentration of 3,5,5-trimethyl-2-cyclohexene-1-one in step 3 is 0.5 mg / mL.
[0065] Example 3
[0066] This embodiment provides a formamidine perovskite solar cell. Compared with Example 1, the difference is that the concentration of 3,5,5-trimethyl-2-cyclohexene-1-one in step 3 is 1.5 mg / mL.
[0067] Comparative Example 1
[0068] This comparative example provides a formamidine perovskite solar cell. Compared with Example 1, the difference is that when preparing the formamidine perovskite active layer in step 3, no 3,5,5-trimethyl-2-cyclohexene-1-one additive is added.
[0069] Test Case
[0070] The performance of the formamidine perovskite solar cells provided in the embodiments of the present invention and the comparative examples was tested. The specific testing method is as follows:
[0071] The current density-voltage (JV) curves of the formamidine perovskite solar cells prepared in the PCE test examples and comparative examples were tested on a Kethley 2400 system under the following test conditions: the simulated light intensity was 100 mW cm -2 (AM 1.5G) scan rate 0.1V s -1The scanning range was 1.2V to -0.2V (step size 0.02V, time delay 200ms), and the xenon lamp power output was calibrated using a NERL (National Renewable Energy Laboratory) KG5 standard Si battery. Detailed test results are shown in Table 1.
[0072] The stability test was conducted on unpackaged formamidine perovskite solar cell devices at room temperature in a nitrogen glove box. Figure 2-Figure 4 .
[0073] The specific test results are shown in the table below:
[0074] Table 1
[0075]
[0076]
[0077] From the examples and comparative examples Figure 2-4 As can be seen from the data in Table 1, the present invention adds 3,5,5-trimethyl-2-cyclohexene-1-one additives when preparing the formamidine perovskite active layer (Examples 1-3). The prepared formamidine perovskite solar cell device has improved photoelectric properties such as open circuit voltage, short circuit current density, and fill factor compared to the device prepared without adding 3,5,5-trimethyl-2-cyclohexene-1-one additives (Comparative Example 1). The formamidine perovskite solar cell device prepared by the method of the present invention has the advantages of high photoelectric conversion efficiency and strong stability.
[0078] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.
Claims
1. A method for preparing a formamidine perovskite active layer, characterized in that: When preparing the formamidine perovskite active layer, 3,5,5-trimethyl-2-cyclohexene-1-one additive is added. The preparation method of the formamidine perovskite active layer is as follows: 3,5,5-trimethyl-2-cyclohexene-1-one, lead iodide, formamidine hydroiodide, and methylamine hydrochloride are dissolved in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide to prepare a formamidine perovskite precursor solution. The prepared formamidine perovskite precursor solution is dropped onto a substrate, and an antisolvent is added onto the rotating substrate, followed by annealing to obtain a formamidine perovskite active layer.
2. The method for preparing a formamidine perovskite active layer according to claim 1, wherein: In the formamidine perovskite precursor solution, the concentration of 3,5,5-trimethyl-2-cyclohexene-1-one is 0.1 to 5 mg / mL.
3. The method for preparing a formamidine perovskite active layer according to claim 1, wherein: The concentration of the formamidinium perovskite component in the formamidinium perovskite precursor solution is 1.5 to 2.0 mmol / mL, and the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is 5:1 to 10:
1.
4. The method for preparing a formamidine perovskite active layer according to claim 1, wherein: The anti-solvent is selected from at least one of chlorobenzene, ether, acetone, toluene, ethyl acetate or chloroform.
5. The method for preparing a formamidine perovskite active layer according to claim 1, wherein: During the preparation of the formamidine perovskite active layer, the rotation speed is 2000 rpm to 8000 rpm, the rotation time is 30s to 80s, and the time for adding the anti-solvent dropwise is 5 to 40s after the start of rotation.
6. The method for preparing a formamidine perovskite active layer according to claim 1, wherein: When preparing the formamidine perovskite active layer, the annealing temperature is 100° C. to 180° C., the annealing time is 10 min to 60 min, the annealing atmosphere is an air environment, and the air humidity is 20% to 50%.
7. The method for preparing a formamidine perovskite active layer according to claim 1, wherein: The thickness of the formamidine perovskite active layer is 300nm to 1500nm.
8. A formamidine perovskite solar cell, characterized in that: The formamidine perovskite solar cell comprises a transparent conductive substrate layer, an electron transport layer, a formamidine perovskite active layer, a passivation layer, a hole transport layer and a metal back electrode arranged in sequence; The formamidine perovskite active layer is prepared by the preparation method according to any one of claims 1 to 7.