Perovskite stress regulation and control material, stress regulation and control method, preparation method of perovskite battery and perovskite battery

Abstract

The invention relates to a perovskite stress regulation and control material, a stress regulation and control method, a preparation method of a perovskite battery and the perovskite battery, and is characterized in that when a perovskite light absorption layer is prepared, short-chain amidine salt is adopted as an additive to effectively regulate and control residual stress in perovskite, and carrier transmission is not affected while the stress is effectively regulated and controlled; therefore, ion migration in the perovskite is inhibited, the defect density of the perovskite thin film is reduced, the efficiency and the stability of the cell are improved, and particularly, the efficiency and the stability of the perovskite-silicon laminated cell are improved.

Description

Technical Field

[0001] The present invention relates to a stress regulation material, a stress regulation method, a preparation method of a perovskite solar cell, and a perovskite solar cell, belonging to the field of photovoltaics. Background Art

[0002] Perovskite solar cells (PSCs) have become a research hotspot for a new generation of photovoltaic technologies due to their advantages of high photoelectric conversion efficiency, low cost, and solution processability. Especially when combined with silicon cells to form a tandem structure, it can overcome the theoretical efficiency limit of single-junction perovskite solar cells and improve the overall photoelectric conversion efficiency. The 4-terminal (4T) tandem structure has great potential in commercial applications due to its high optical design freedom and good compatibility. However, the mismatch between the thermal expansion coefficients of perovskite and silicon cells, combined with the combined action of external factors such as moisture, oxygen, and light, will generate significant stress in the perovskite layer. It is worth noting that the residual tensile stress is a key factor affecting the performance and stability of PSC devices. It will accelerate the process of ion migration and drive the formation of defects, and the combined action of the two will ultimately affect the stability of PSC devices. Therefore, there is an urgent need for an effective method to prepare a stable and strain-free perovskite thin film to achieve an efficient and stable 4T perovskite-silicon tandem solar cell.

[0003] Additive engineering as a strategy for regulating perovskite lattice strain has been widely reported. For example, Chen et al. squeezed the lattice by adding zwitterionic adenosine triphosphate (ATP) at grain boundaries, thereby converting tensile strain into compressive strain. In addition, by adding long-chain spacers (such as butylamine (BA + ), phenethylamine (PEA + ), oleylamine (OA + )) into 3D perovskites to construct 2D / 3D hybrid perovskites, providing structural flexibility to relieve stress. However, these long-chain additives or the low-dimensional structures formed by them are usually limited to grain boundaries or surfaces and usually exhibit insulating properties, which may have a negative impact on the extraction and transport of carriers. Summary of the Invention

[0004] Aiming at the problem of residual tensile stress in the perovskite layer, the present invention provides a stress regulation material, a regulation method, a perovskite solar cell, and a preparation method of a perovskite solar cell. Short-chain amidine salts are used as additives to effectively regulate the residual stress inside the perovskite, without affecting the transport of carriers while effectively regulating the stress, thereby inhibiting ion migration in the perovskite, reducing the defect density of the perovskite thin film, and improving the efficiency and stability of the battery, especially improving the efficiency and stability of the perovskite-silicon tandem battery.

[0005] To achieve the above object, on the one hand, the present invention provides a stress regulation material for a perovskite light-absorbing layer, and the structural formula of the material is:

[0006]

[0007] In the formula, R is phenyl or methyl, and X is a halogen anion, which can be I - , Br - , Cl - or one or more of them.

[0008] Further preferably, R is phenyl, and the structural formula of the material is:

[0009]

[0010] As a preferred material, the material is BHAMAX, that is in the preferred structural formula, X is I - .

[0011] In a second aspect, the present invention provides a method for regulating the stress of a perovskite light-absorbing layer. The regulator in the first aspect is used as an additive to regulate the stress of the perovskite light-absorbing layer. Specifically, one of the following methods can be selected: Method 1, obtain the regulator; add a certain amount of the regulator to the perovskite light-absorbing layer material for regulation; Method 2, place the precursor material of the regulator in the perovskite precursor solution, and the precursor material of the regulator reacts with a certain component in the perovskite precursor solution to obtain the regulator; on this basis, the perovskite light-absorbing layer is obtained by spin-coating, blade-coating, etc. with the perovskite precursor solution containing the regulator, or other components can be added to the perovskite precursor solution containing the regulator as needed, and then the final perovskite precursor solution is formed, and then spin-coated, blade-coated, etc. and annealed to obtain the perovskite light-absorbing layer.

[0012] Preferably, the perovskite is ABX3, A is an organic or / and inorganic monovalent cation, B is Pb 2+ , and X is a halogen ion. Calculated in terms of molar amount, the content of the regulator is 0.42 - 0.83 mol% of the content of Pb 2+ .

[0013] As a preference, Method 2 is adopted, and the specific steps are:

[0014] Prepare a perovskite precursor solution, and the precursor solution contains FAX, where X is I - , Cl - , Br - or one or more of them;

[0015] Add the precursor of the regulator to the perovskite precursor solution, and the structural formula of the precursor of the regulator is:

[0016] wherein R is phenyl or methyl, X is a halogen anion selected from I - , Cl - , Br - , and it can be the same element or different elements as X in FAX.

[0017] The regulator precursor fully reacts with FAX in the perovskite precursor solution to obtain the regulator;

[0018] Use the perovskite precursor solution containing the regulator to prepare a perovskite light-absorbing layer.

[0019] As a preference, the perovskite precursor solution contains at least formamidinium salt, and more preferably formamidinium iodide (FAI). Under heating conditions, the regulator precursor reacts with FAI to obtain the regulator BHAMAI.

[0020] As a preference, the regulator precursor is: Preferably X is I - , and the regulator precursor is benzamidine hydrochloride.

[0021] As a preference, the regulation method includes the following steps: S01 Mix benzamidine hydrochloride with the perovskite precursor solution containing formamidinium salt; S02 The formamidinium salt in the perovskite precursor solution fully reacts with benzamidine hydrochloride to obtain a perovskite precursor solution with N-formamidino benzamidine as the cationic group; S03 Use the perovskite precursor solution with N-formamidino benzamidine as the cationic group to prepare a perovskite light-absorbing layer.

[0022] As a preference, the molar ratio of benzamidine hydrochloride to formamidinium ion is (0.5 - 0.9):100.

[0023] As a preference, the reaction temperature of formamidinium ion and benzamidine hydrochloride in the perovskite precursor solution is 50 - 65 °C. That is, under heating conditions, formamidinium ion and benzamidine hydrochloride can react, and the heating temperature is 50 - 65 °C. Exceeding this temperature range will cause the generation of two-dimensional perovskite or other adverse impurities.

[0024] As a preference, the solutes in the perovskite precursor solution are cesium iodide, formamidinium iodide, methylammonium bromide, lead iodide, and lead bromide, and the solvent of the perovskite precursor solution is DMF and DMSO, and the ratio of the two is (3 - 5):1.

[0025] As a preference, the reaction formula involved in the reaction of benzamidine hydrochloride (BHACl) with formamidinium ion is as follows:

[0026]

[0027] Thirdly, the present invention provides a preparation method of a perovskite solar cell. An organic salt with N-formamidinium benzamidine as a cationic group obtained in the first aspect is used as an additive and doped in a perovskite precursor to prepare a perovskite light-absorbing layer. The perovskite obtained by the regulation method of the second aspect can also be used.

[0028] Preferably, the preparation method of the perovskite solar cell specifically includes the following steps:

[0029] S01 Obtain a substrate;

[0030] S02 Prepare a hole transport layer on the substrate;

[0031] S03 Prepare a perovskite light-absorbing layer on the hole transport layer;

[0032] S04 Prepare an electron transport layer on the perovskite light-absorbing layer;

[0033] S05 Prepare a hole blocking layer on the electron transport layer;

[0034] S06 Prepare an electrode layer on the hole blocking layer.

[0035] The preparation method of the perovskite light-absorbing layer is as follows:

[0036] A. Prepare a perovskite precursor solution. There is formamidinium salt in the perovskite precursor solution, which can be one or more of formamidinium iodide, formamidinium bromide, and formamidinium chloride; the perovskite precursor solution can also include inorganic salts or other organic salts, such as one or more of cesium iodide, methylammonium bromide, lead iodide, and lead bromide; the solvent in the precursor solution is a mixed solvent of DMF and DMSO;

[0037] B. Add benzamidine hydrochloride to the perovskite precursor solution and stir to mix the benzamidine hydrochloride with the precursor solution; C. Heat the perovskite precursor solution to make the benzamidine hydrochloride react with formamidinium ions in the perovskite precursor solution to obtain N-formamidinium benzamidine. HCl gas and NH3 gas are released during the reaction. The reaction formula during the reaction is:

[0038]

[0039] During the reaction, the =NH2 of the BHACl molecule + will undergo deprotonation under heating conditions, that is, =NH2 + loses a H atom to generate the process of =NH. During this period, HCl gas is released, and the HCl gas does not participate in the subsequent perovskite crystallization. When the precursor contains formamidinium iodide (FAI), the deprotonated BHA will spontaneously react with FAI to generate N-formamidinium benzamidine (BHAMA + ), and NH3 gas is released during this period. NH3 does not participate in the subsequent perovskite crystallization. BHAMA+ Compared with BHACl, there are more N atoms in BHAMA+. After the hydrogen atom of BHAMA+ forms a polar covalent bond with a more electronegative N atom, its partial positive charge will attract the more electronegative I atom in the perovskite octahedron, thus forming a hydrogen bond in the form of N-H…I. Therefore, BHAMA+ can form more hydrogen bonds with the perovskite octahedron, stabilize the structure, and thus more effectively regulate the strain.

[0040] At this time, the perovskite precursor solution contains the regulator N-formamidinium benzamidine. The perovskite precursor solution containing N-formamidinium benzamidine is coated on the hole transport layer, the annealing temperature is 90-110 °C, and the annealing time is 10 min to obtain the perovskite absorption layer. Preferably, the thickness of the perovskite thin film is 500-600 nm, the thickness of the C60 electron transport layer in step (4) is 20-30 nm, the thickness of the BCP hole blocking layer is 8-10 nm, and the thickness of the Cu electrode is 150-200 nm.

[0041] As a preference, the hole transport layer material is MeO-2PACZ. The electron transport layer material is C60, and the hole blocking layer material is BCP.

[0042] As a preference, the substrate is a silicon cell, the perovskite cell is the top cell, and the silicon cell is the bottom cell. Further preferably, the silicon cell and the perovskite cell form a four-terminal stacked cell.

[0043] In the fourth aspect, the present invention provides a perovskite cell, which uses the additive in the first aspect to prepare the light-absorbing layer or uses the perovskite preparation method in the second aspect to prepare the light-absorbing layer or is a perovskite cell prepared by the preparation method in the third aspect.

[0044] As a preference, the perovskite cell is a single-junction cell or a multi-junction cell, and can be a stacked cell formed by perovskite and other photovoltaic cells, especially a four-terminal cell formed by perovskite and silicon, where the perovskite cell is the top cell, silicon is the bottom cell, and the perovskite cell is a wide-bandgap cell.

[0045] The beneficial effects produced by the present invention include: The regulator in the present invention effectively reduces the volume expansion and contraction during the perovskite thermal cycle, thereby releasing the strain while not affecting the carrier transport. The release of the strain increases the ion migration barrier and the defect formation energy, thereby improving the efficiency and stability of single-junction and stacked cells.

[0046] In the present invention, BHACl is preferably used as the regulator precursor, and there are the following advantages: BHACl has a short chain length and has little influence on carrier transport; one amino group of BHACl is prone to deprotonation under heating conditions, and the deprotonated amino group will undergo an in-situ addition reaction with formamidinium iodide (FAI) to generate BHAMA+ , reducing the FA vacancies and anchoring at the A-site, rather than existing at grain boundaries or surfaces; BHAMA + The remaining amino groups of BHAMA strongly interact with the lead iodide octahedra to fix the halide ions. Description of the Drawings

[0047] Figure 1 Schematic diagram of the structure of the four-terminal stacked cell in Example 2;

[0048] Figure 2 This is the 1H NMR spectrum of BHAMA formed by BHACl, FAI and their in-situ reaction in Example 1 of the present invention + ;

[0049] Figures 3(a) and 3(b) show the stress changes in the perovskite films obtained in Example 1 and the comparative example of the present invention, respectively;

[0050] Figures 4(a) and 4(b) show the steady-state photoluminescence spectrum PL and time-resolved photoluminescence spectrum TRPL of the perovskite films obtained in Example 1 and the comparative example of the present invention, respectively;

[0051] Figure 5 This is the current-voltage (J-V) curve of the perovskite devices obtained in Example 1 and the comparative example of the present invention;

[0052] Figure 6 This is the current-voltage (J-V) curve of the 4T perovskite-silicon stacked solar cell obtained in Example 2 of the present invention;

[0053] Figure 7 This is the outdoor stability test curve of the 4T perovskite-silicon stacked solar cell obtained in Example 2 of the present invention. Detailed Embodiments

[0054] The present invention will be further described below in the form of detailed embodiments, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0055] Example 1

[0056] An inverted perovskite solar cell uses benzamidine hydrochloride (BHACl) as a stress regulator precursor for the wide-bandgap perovskite absorption layer, and can play a role in regulating the stress of the perovskite layer after mixing and reacting with the perovskite precursor solution.

[0057] The preparation method of the perovskite cell is as follows:

[0058] (1) Cleaning ITO glass: Commercial ITO glass was selected as the substrate material. It was ultrasonically cleaned with conductive glass cleaning solution, deionized water, and absolute ethanol for 30 min respectively, then dried with a nitrogen gun, and after ultraviolet ozone treatment for 30 min, it was transferred to a glove box for standby.

[0059] (2) Preparing the hole transport layer MeO-2PACZ solution: Weigh [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid (MeO-2PACZ) and dissolve it in absolute ethanol at room temperature, with a concentration of 0.5 mg / ml.

[0060] (3) Preparing the perovskite precursor solution: Cesium iodide, formamidinium iodide, methylammonium bromide, lead iodide, and lead bromide were dissolved in a mixed solvent (DMF:DMSO = 4:1) at a molar ratio of 1:16:14:6 and stirred at 60 °C for 1 h.

[0061] (4) Add BHACl to the mixed solution obtained in step (3) and stir at 60 °C for 1 h. The following reaction occurs between BHACl and the perovskite precursor solution:

[0062]

[0063] Furthermore, a perovskite precursor solution doped with BHAMA+ is obtained, where the molar ratio of BHACl is 0.5%; a perovskite precursor solution with a total concentration of 1.7 mol / L is prepared.

[0064] (5) Preparing the perovskite film: Drop 100 μL of the Meo-2PACZ solution on the ITO glass and spin-coat it at 4000 rpm for 30 s, then transfer it to a hot plate at 120 °C for annealing for 20 min to obtain the hole transport layer with a thickness of about 5 - 10 nm; then drop 100 μL of the perovskite precursor solution obtained in step (4) on the hole transport layer, spin-coat it at 4000 rpm for 40 s, and drop 150 μL of the antisolvent chlorobenzene at the 8th s after the spin-coating ends, then transfer it to a hot plate at 100 °C for annealing for 10 min to obtain the perovskite film with a thickness of about 600 nm.

[0065] (5) Fabricating the device: Transfer the perovskite film prepared in step (4) to a vacuum chamber, and sequentially deposit a 30-nm electron transport layer C60, an 8-nm hole blocking layer BCP, and a 200-nm metal electrode Cu by thermal evaporation.

[0066] Example 2

[0067] A 4T perovskite-silicon tandem solar cell uses benzamidine hydrochloride (BHACl) as a precursor for stress regulation of the wide-bandgap perovskite absorption layer, and can play a role in regulating the stress of the perovskite layer after mixing and reacting with the perovskite precursor solution.

[0068] The preparation method of this battery is as follows:

[0069] (1) Clean the ITO glass: Select commercial ITO glass as the substrate material, ultrasonically clean it with conductive glass cleaning solution, deionized water, and absolute ethanol for 30 minutes respectively, then dry it with a nitrogen gun, and transfer it to the glove box after ultraviolet ozone treatment for 30 minutes for standby.

[0070] (2) Prepare the hole transport layer Meo-2PACZ solution: Weigh [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid (Meo-2PACZ) and dissolve it in absolute ethanol at room temperature, with a concentration of 0.5 mg / ml.

[0071] (3) Prepare the perovskite precursor solution: Dissolve cesium iodide, formamidinium iodide, methylammonium bromide, lead iodide, and lead bromide in a mixed solvent (DMF:DMSO = 4:1) at a molar ratio of 1:16:14:6, and stir at 60 °C for 1 h.

[0072] (4) Add BHACl to the mixed solution and stir at 60 °C for 1 h to obtain a perovskite precursor solution doped with BHAMA+, where the molar ratio of BHACl is 0.5%; prepare a perovskite precursor solution with a total concentration of 1.7 mol / L.

[0073] (5) Prepare the perovskite thin film: Drop 100 μL of Meo-2PACZ solution on the ITO glass, spin-coat it at 4000 rpm for 30 s, and then transfer it to a hot plate at 120 °C for annealing for 20 min to obtain the hole transport layer with a thickness of about 5 - 10 nm; then drop 100 μL of the perovskite precursor solution obtained in step (4) on the hole transport layer, spin-coat it at 4000 rpm for 40 s, and drop 150 μL of the antisolvent chlorobenzene at the 8th s after the end of spin-coating, and then transfer it to a hot plate at 100 °C for annealing for 10 min to obtain the perovskite thin film with a thickness of about 600 nm.

[0074] (6) Prepare the semi-transparent battery device: Transfer the perovskite thin film prepared in step (5) to a vacuum chamber, deposit 12 nm of the electron transport layer C60 by thermal evaporation method and deposit 10 nm of the hole blocking layer SnO2 by atomic layer deposition method, and then deposit 40 nm of indium zinc oxide IZO as the semi-transparent electrode by magnetron sputtering.

[0075] (7) Prepare the 4T stacked device: Use a commercial double-sided silicon heterojunction (SHJ) solar cell as the bottom cell in the 4T stacked cell, and mechanically stack the semi-transparent perovskite solar cell prepared in step (6) above the silicon cell to obtain the 4T perovskite-silicon stacked solar cell.

[0076] Comparative example

[0077] An inverted perovskite solar cell that does not use BHACl as an additive for the wide-bandgap perovskite absorption layer, and the preparation method of the cell is as follows:

[0078] (1) Cleaning ITO glass: Select commercial ITO glass as the substrate material, ultrasonically clean it with conductive glass cleaning solution, deionized water, and absolute ethanol for 30 min respectively, then dry it with a nitrogen gun, and transfer it to the glove box for standby after ultraviolet ozone treatment for 30 min.

[0079] (2) Preparing the hole transport layer Meo-2PACZ solution: Weigh [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid (Meo-2PACZ) and dissolve it in absolute ethanol with a concentration of 0.5 mg / ml.

[0080] (3) Preparing the perovskite precursor solution: Dissolve cesium iodide, formamidinium iodide, methylammonium bromide, lead iodide, and lead bromide in a mixed solvent (DMF:DMSO = 4:1) at a molar ratio of 1:16:14:6, and stir at 60 °C for 1 h; obtain a perovskite precursor solution with a total concentration of 1.7 mol / L.

[0081] (4) Preparing the perovskite film: Drop 100 μL of Meo-2PACZ solution on the ITO glass, spin-coat it at 4000 rpm for 30 s, and then transfer it to a hot plate at 120 °C for annealing for 20 min to obtain the hole transport layer with a thickness of about 5-10 nm; then drop 100 μL of the perovskite precursor solution on the hole transport layer, spin-coat it at 4000 rpm for 40 s, and drop 150 μL of the antisolvent chlorobenzene at the 8th s after the end of spin-coating, and then transfer it to a hot plate at 100 °C for annealing for 10 min to obtain the perovskite film with a thickness of about 600 nm.

[0082] Fabricating the device: Transfer the perovskite film prepared in step (4) to a vacuum chamber, and sequentially deposit a 30-nm electron transport layer C60, an 8-nm hole blocking layer BCP, and a 200-nm metal electrode Cu by thermal evaporation.

[0083] Testing the solar cells prepared in Example 1, Example 2, and the comparative example, and the obtained results are as follows:

[0084] For convenience, the sample without doping BHAMA in the comparative example + is denoted as Control, and the samples doped with BHAMA in Example 1 and Example 2 + are denoted as Target.

[0085] 1. Determining whether BHACl and FAI undergo an in-situ reaction to generate BHAMA in Example 1 and Example 2 + . The nuclear magnetic resonance hydrogen spectra of BHACl, FAI, and their mixed solution were tested, asFigure 2 As shown, the =NH peak of BHACl and the -NH peak of FAI disappeared, and instead, the =NH peak belonging to BHAMA appeared in the mixed solution of the two, + which confirmed the + in-situ formation of BHAMA.

[0086] 2. Measure the ability of BHAMA + to regulate the perovskite strain. Figure 3 shows grazing-incidence X-ray diffraction of different depths of the perovskite film to analyze the stress changes at different depths. As the X-ray diffraction depth increases, the XRD peak position of the undoped BHAMA + perovskite film shifts to the left, indicating the existence of tensile stress. The XRD peak position of the perovskite film doped with BHAMA + does not shift, indicating that the strain is successfully released.

[0087] 3. Measure the carrier transport performance. As shown in Figure 4, the perovskite film containing BHAMA + has higher PL and longer carrier lifetime, indicating that BHAMA + does not affect the carrier transport.

[0088] 4. Measure the photovoltaic performance of the single-junction perovskite solar cell in Example 1. As Figure 5 shown, the J-V curve of the perovskite solar cell doped with BHAMA + shows a higher open-circuit voltage and photoelectric conversion efficiency, which are 1.24 V and 22.5% respectively.

[0089] 5. Measure the photovoltaic performance of the 4T perovskite-silicon tandem solar cell in Example 2. As Figure 6 shown, the efficiency of the prepared semi-transparent perovskite solar cell reaches 21.8%, and the efficiency of the silicon bottom solar cell reaches 11.0%. Therefore, a high efficiency of 32.8% is achieved overall, which is one of the highest efficiencies of 4T perovskite-silicon tandem solar cells to date.

[0090] 6. Measure the stability of the 4T perovskite-silicon tandem solar cell. The encapsulated 4T tandem device was placed in an outdoor environment for stability testing. As Figure 7 shown, after 48 days and nights of cyclic testing, the efficiency remains almost unchanged, showing excellent outdoor operation stability.

[0091] It is emphasized again that the protection scope of the present invention should not be construed as being limited by the description in the specification. Unless otherwise specified, any range recited in the present invention includes the end values and any numerical value between the end values, as well as any sub-range formed by any numerical value between the end values or the end values. For all raw materials of the present invention, there is no special limitation on their purity, and the present invention preferably uses analytical pure. For all raw materials of the present invention, their sources and abbreviations are all conventional sources and abbreviations in the art, and are clear and definite in the field of their relevant uses. Those skilled in the art can obtain them from the market or prepare them by conventional methods according to the abbreviations and corresponding uses.

[0092] "At least one" means one or more, and "a plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. "At least one (item)" or similar expressions thereof refer to any combination of these items, including any combination of single item (s) or plural items (s). For example, at least one (item) of a, b or c can represent: a, b, c, the combination of a and b, the combination of a and c, the combination of b and c, or the combination of a, b and c, where a, b and c can be single or multiple.

Claims

1. A perovskite light-absorbing layer stress regulation material, characterized in that: The structural formula of the material is: In the formula, R is phenyl or methyl, and X is a halogen anion.

2. The material according to claim 1, wherein: The structural formula is Wherein X is a halogen anion.

3. A method for regulating the stress of a perovskite light-absorbing layer, characterized in that: Using the material in Claim 1 or Claim 2 as an additive for the perovskite light-absorbing layer to prepare the perovskite light-absorbing layer.

4. The method for regulating the stress of the perovskite light-absorbing layer according to claim 3, wherein: The perovskite is ABX3, where A is an organic or / and inorganic monovalent cation, B is Pb 2+ , X is a halogen anion, and the added molar amount of the regulator is 0.42 to 0.83 mol% of the molar amount of Pb in the perovskite 2+ .

5. The method for regulating the stress of the perovskite light-absorbing layer according to claim 3, wherein: The regulator is formed by the reaction of a regulator precursor and a perovskite precursor, and includes the following steps: Prepare a perovskite precursor solution, wherein the precursor solution contains FAX, and X is I - , Cl - , Br - or one or more of them; Adding the precursor of the regulator to the perovskite precursor solution, and the structural formula of the precursor of the regulator is: wherein R is phenyl or methyl, and X is a halogen anion; The precursor of the regulator fully reacts with FAX in the perovskite precursor solution to obtain the regulator; Using the perovskite precursor solution containing the regulator to prepare a perovskite light-absorbing layer.

6. The method for regulating the stress of the perovskite light-absorbing layer according to claim 5, wherein: The structural formula of the precursor of the regulator is: Wherein X is Cl - 、I - 、Br - or one of them.

7. The method for regulating the stress of the perovskite light-absorbing layer according to claim 5, characterized in that: The molar ratio of the precursor of the regulator to the molar amount of FAX in the perovskite precursor solution is (0.5 - 0.9):

100.

8. A method for preparing a perovskite solar cell, comprising the following steps: Using the regulation method described in Claims 3 - 7 to regulate the stress of the perovskite light-absorbing layer to obtain the perovskite light-absorbing layer.

9. The method for preparing a perovskite solar cell according to Claim 8, wherein: It includes the following steps: S01 Obtaining a substrate; S02 Preparing a hole transport layer on the substrate; S03 Preparing a perovskite light-absorbing layer on the hole transport layer; S04 Preparing an electron transport layer on the perovskite light-absorbing layer; S05 Preparing a hole blocking layer on the electron transport layer; S06 Preparing an electrode layer on the hole blocking layer. The method for preparing the perovskite light-absorbing layer is: A. Preparing a perovskite precursor solution, the perovskite precursor solution contains at least FAX, and the solvent in the perovskite precursor solution is a mixed solvent of DMF and DMSO; B. Adding benzamidine hydrochloride to the perovskite precursor solution, and stirring to mix the benzamidine hydrochloride with the perovskite precursor solution; C. Heating the perovskite precursor solution to make benzamidine hydrochloride react with formamidinium ions in the perovskite precursor solution to obtain N-formamidino benzamidine; D. Coating the perovskite precursor solution containing N-formamidino benzamidine on the hole transport layer and annealing to obtain the perovskite light-absorbing layer.

10. A perovskite single-junction cell or multi-junction cell, characterized in that: Prepared using the additive described in Claims 1 - 3 or prepared using the preparation method described in Claims 8 - 9.

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