Additive strategy optimized perovskite solar cell and preparation method thereof

Abstract

The invention provides an additive strategy optimized perovskite solar cell and a preparation method thereof, the perovskite solar cell sequentially comprises a transparent conductive substrate, a first carrier transport layer, a perovskite thin film, a second carrier transport layer, a buffer layer and a back electrode layer from bottom to top, the perovskite thin film comprises a perovskite material and an additive, the perovskite material is mixed cation perovskite, and the additive is 1-pyrene butyric acid; according to the additive strategy optimized perovskite solar cell and the preparation method thereof, the additive 1-pyrene butyric acid is introduced in the preparation of the perovskite thin film to regulate and control the crystallization process of the perovskite thin film, the perovskite thin film with larger crystal grains and fewer defects is finally generated, the defect density of the perovskite thin film is reduced, and the performance of the solar cell is improved. And the crystal quality of the perovskite thin film is improved, so that the transmission and extraction of current carriers are promoted, the performance of a perovskite solar cell device is greatly improved, and the perovskite solar cell with high photoelectric conversion efficiency is obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar cells, and particularly relates to a perovskite solar cell with optimized additive strategy and a preparation method thereof. Background Art

[0002] Perovskite solar cells have become a highly regarded next-generation photovoltaic technology due to their excellent optoelectronic properties, such as high absorption coefficient, tunable bandgap, and long carrier diffusion length. These unique performance advantages, combined with their potential for low-cost and high-throughput manufacturing capabilities, make perovskite solar cells (PSCs) highly competitive in future photovoltaic applications. In recent years, with the growing interest in PSC research, a large amount of research work and investment have been devoted to improving their performance and scalability.

[0003] Currently, the power conversion efficiency of perovskite solar cells has exceeded 26%, but there is still a gap from its theoretical efficiency, which is mainly due to the internal defects of the perovskite film. The crystallization process of the perovskite film often affects the defects of the perovskite film; during the crystallization process of the perovskite film, the accuracy of controlling conditions is crucial for ensuring the uniformity of crystal growth and reducing the formation of defects. Improper control conditions often lead to uneven crystal growth, which significantly increases the number of defects at grain boundaries. These defects not only have an adverse effect on the overall structure of the perovskite material but may also form trap states between the bandgaps of the material. Under environmental conditions such as an applied electric field or water / oxygen penetration, these trap states will significantly promote the occurrence of non-radiative charge recombination, thus severely reducing the efficiency of the device.

[0004] In addition, other types of defects such as crystal orientation defects and grain boundary defects are also easily formed during the preparation of perovskite materials. These defects also increase the non-radiative recombination energy loss of carriers, thereby restricting the improvement of the open-circuit voltage and fill factor of the device; these problems not only directly affect the performance of perovskite solar cells but also pose severe challenges to their practical applications and commercialization processes.

[0005] Therefore, how to reduce the formation of defects during the preparation process and improve the performance of perovskite solar cells has become a technical problem that urgently needs to be solved. Summary of the Invention

[0006] Aiming at the above technical problems, the purpose of the present invention is to provide a perovskite solar cell with optimized additive strategy and a preparation method thereof, which uses the reaction of additive 1-pyrenebutyric acid with perovskite materials to reduce various defects during the preparation process of perovskite films and improve the performance of perovskite solar cells.

[0007] To achieve the above purpose, the present invention adopts the following technical solutions:

[0008] In the first aspect of the present invention, there is provided a perovskite solar cell with optimized additive strategy, which sequentially includes a transparent conductive substrate, a first carrier transport layer, a perovskite thin film, a second carrier transport layer, a buffer layer and a back electrode layer from bottom to top. The perovskite thin film includes a perovskite material and an additive. The perovskite material is a mixed cation perovskite, and the additive is 1-pyrenebutyric acid.

[0009] Further, the mixed cation perovskite is ABX3, wherein the A site includes, but is not limited to, Cs + , MA + , FA + or one or more of them; the B site includes, but is not limited to, Pb 2+ , Sn 2+ , Ge2+ or one or more of them; the X site includes, but is not limited to, I - , Br - , Cl - or one or more of them.

[0010] Further, the mixed cation perovskite includes, but is not limited to, FA x MA 1-x PbI3, FA x Cs 1-x PbI3, MAPb x Sn 1-x I y Br 3-y , FA x MA 1-x PbI y Br 3-y or one or more of them.

[0011] Further, the first carrier transport layer is an electron transport layer or a hole transport layer, and the second carrier transport layer corresponds to the first carrier transport layer; when the first carrier transport layer is an electron transport layer, the second carrier transport layer is a hole transport layer; when the first carrier transport layer is a hole transport layer, the second carrier transport layer is an electron transport layer.

[0012] Further, the transparent conductive substrate is ITO conductive glass or FTO conductive glass.

[0013] Further, the hole transport layer is a p-type inorganic semiconductor material and / or a p-type organic semiconductor material, including but not limited to poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), 2,2',7,7'-tetrakis[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD), poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS), polyvinylcarbazole (PVK), poly(4-butyl-N,N-diphenylaniline) (Ploy-TPD), [2-(9H-carbazol-9-yl)ethyl]phosphonic acid (2PACz), [3-(9H-carbazol-9-yl)ethyl]phosphonic acid (3PACz), [4-(9H-carbazol-9-yl)ethyl]phosphonic acid (4PACz), CuI, CuSCN, or one or more of them.

[0014] Further, the electron transport layer is an n-type inorganic semiconductor material and / or an n-type organic semiconductor material, including but not limited to TiO2, SnO2, C 60 or one or more of PCBM.

[0015] Further, the buffer layer is one of MoO x , V2O5, BCP, or SnO2.

[0016] Further, the back electrode layer is one of Au, Ag, Cu, or a carbon electrode.

[0017] Further, the structural formula of the additive 1-pyrenebutyric acid is

[0018]

[0019] The second aspect of the present invention lies in providing a preparation method of the above perovskite solar cell, including the following steps:

[0020] S1. Cleaning the transparent conductive substrate;

[0021] S2. Preparing a first carrier transport layer on the transparent conductive substrate;

[0022] S3. Preparing a perovskite thin film on the first carrier transport layer;

[0023] S4. Preparing a second carrier transport layer on the perovskite thin film;

[0024] S5. Preparing a buffer layer on the second carrier transport layer;

[0025] S6. Preparing a back electrode layer on the buffer layer;

[0026] Among them, the preparation steps of the perovskite thin film include:

[0027] The perovskite precursor material and the additive 1-pyrenebutyric acid are placed in a solvent to obtain a perovskite precursor solution, which is then coated on the upper surface of the first carrier transport layer and annealed to obtain a perovskite thin film comprising a perovskite material and 1-pyrenebutyric acid. The solvent is one or more of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), γ-butyrolactone (GBL), dimethylacetamide (DMA), N,N-dimethylpropyleneurea (DMPU), and acetonitrile. The coating method is one of spin coating, blade coating, or slot die coating.

[0028] Furthermore, the concentration of the mixed cation perovskite in the perovskite precursor solution is 1 to 1.8 M, and the concentration of 1-pyrenebutyric acid is 0.1 to 1 mg / mL.

[0029] When the amount of 1-pyrenebutyric acid in the perovskite precursor solution is too low (below 0.1 mg / mL), it is difficult to form a complete and effective modification layer on the surface and interface of the perovskite thin film, resulting in increased charge recombination, limited open-circuit voltage and fill factor of the battery, and it is difficult to significantly improve the photoelectric conversion efficiency. When the concentration of 1-pyrenebutyric acid in the perovskite precursor solution is too high (above 1.0 mg / mL), it will interfere with the growth of perovskite crystals, distort the crystal structure, and lead to a decline in the performance of perovskite solar cell devices.

[0030] Compared with the prior art, the present invention has at least the following beneficial effects:

[0031] 1. For the perovskite solar cell and its preparation method optimized by the additive strategy of the present invention, the additive 1-pyrenebutyric acid is introduced in the preparation of the perovskite thin film to regulate the crystallization process of the perovskite thin film, and finally a perovskite thin film with larger grains and fewer defects is generated, reducing the defect density of the perovskite thin film, improving the crystal quality of the perovskite thin film, and further promoting the transport and extraction of carriers, thereby greatly improving the performance of perovskite solar cell devices and obtaining perovskite solar cells with high photoelectric conversion efficiency.

[0032] 2. For the perovskite solar cell and its preparation method optimized by the additive strategy of the present invention, through the interaction between 1-pyrenebutyric acid molecules and perovskite molecules, the crystallization growth process of perovskite is effectively regulated, making the crystallization of the perovskite thin film better and the regularity of the grains higher, thereby reducing non-radiative recombination centers and improving the photoelectric properties of the perovskite thin film. At the same time, the molecular size of 1-pyrenebutyric acid is relatively large and cannot enter the lattice of perovskite. During the film formation process of perovskite, 1-pyrenebutyric acid will shift towards the two side interfaces due to the molecular extrusion process, improving the interface characteristics, and further enhancing the photoelectric conversion efficiency of perovskite solar cell devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of the structure of a perovskite solar cell with optimized additive strategy of the present invention;

[0034] In the figure: 1 - transparent conductive substrate; 2 - first carrier transport layer; 3 - perovskite thin film; 4 - second carrier transport layer; 5 - buffer layer; 6 - back electrode layer.

[0035] Figure 2 Among them, (a) is the SEM image of the perovskite thin film in Comparative Example 1, and (b) is the SEM image of the perovskite thin film in Example 1. Detailed implementation manners

[0036] The present invention will be further described below in conjunction with the accompanying drawings through specific examples. It should be understood that these examples are only used to illustrate the present invention and not to limit the scope of the present invention.

[0037] See Figure 1 , the first aspect of the present invention provides a perovskite solar cell with optimized additive strategy, which sequentially includes a transparent conductive substrate 1, a first carrier transport layer 2, a perovskite thin film 3, a second carrier transport layer 4, a buffer layer 5 and a back electrode layer 6 from bottom to top. The perovskite thin film 3 includes a perovskite material and an additive. The perovskite material is a mixed cation perovskite, and the additive is 1-pyrenebutyric acid. 1-Pyrenebutyric acid is a pyrene-based material. Pyrene, as a classic polycyclic aromatic compound, has large π-conjugation and unique photophysical properties. Due to its easy modification of the structure, it has a variety of functionalization strategies. The structural formula of 1-pyrenebutyric acid is:

[0038]

[0039] The present invention introduces the additive 1-pyrenebutyric acid in the preparation of the perovskite thin film. Through the interaction between 1-pyrenebutyric acid molecules and perovskite molecules, it can effectively regulate the crystallization growth process of perovskite, make the crystallinity of the perovskite thin film better, improve the regularity of crystal grains, thereby reducing non-radiative recombination centers and improving the optoelectronic properties of the perovskite thin film; at the same time, the size of 1-pyrenebutyric acid is relatively large and cannot enter the lattice of perovskite. During the perovskite film formation process, 1-pyrenebutyric acid will shift towards the two side interfaces due to the molecular extrusion process, improving the interface characteristics, and further enhancing the photoelectric conversion efficiency of the perovskite solar cell device.

[0040] It should be noted that the additive 1-pyrenebutyric acid used in the present invention is a commercially available 1-pyrenebutyric acid reagent.

[0041] Furthermore, the mixed cation perovskite is ABX3, where the A site includes but is not limited to Cs + , MA + , FA + one or more of them; the B site includes but is not limited to Pb2+ , Sn 2+ , one or more of Ge2+; the X site includes but is not limited to I - , Br - , Cl - one or more of the following.

[0042] Furthermore, the mixed cation perovskite includes but is not limited to FA x , MA 1-x , FA x , Cs 1-x , PbI3, FA x , Sn 1-x , I y , Br 3-y , FA x , MA 1-x , PbI y , Br 3-y one or more of the following.

[0043] Further, the first carrier transport layer 2 is an electron transport layer or a hole transport layer, and the second carrier transport layer 4 corresponds to the first carrier transport layer 2; when the first carrier transport layer 2 is an electron transport layer, the second carrier transport layer 4 is a hole transport layer; when the first carrier transport layer 2 is a hole transport layer, the second carrier transport layer 4 is an electron transport layer.

[0044] Further, the transparent conductive substrate 1 is ITO conductive glass or FTO conductive glass.

[0045] Further, the hole transport layer is a p-type inorganic semiconductor material and / or a p-type organic semiconductor material, including but not limited to poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), 2,2',7,7'-tetrakis[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD), poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS), polyvinylcarbazole (PVK), 4-butyl-N,N-diphenylaniline homopolymer (Ploy-TPD), [2-(9H-carbazol-9-yl)ethyl]phosphonic acid (2PACz), [3-(9H-carbazol-9-yl)ethyl]phosphonic acid (3PACz), [4-(9H-carbazol-9-yl)ethyl]phosphonic acid (4PACz), CuI, CuSCN, or one or more of the above.

[0046] Further, the electron transport layer is an n-type inorganic semiconductor material and / or an n-type organic semiconductor material, including but not limited to TiO2, SnO2, C 60 or one or more of PCBM.

[0047] Further, the buffer layer 5 is one of MoO x , V2O5, BCP or SnO2; the setting of the buffer layer 5 can improve the interface contact, reduce the interface defects, and adjust the energy level matching, thereby improving the performance and stability of the battery.

[0048] Further, the back electrode layer 6 is one of Au, Ag, Cu or a carbon electrode.

[0049] Continue to refer to Figure 1 , the second aspect of the present invention provides a method for preparing the above perovskite solar cell, comprising the following steps:

[0050] S1. Cleaning the transparent conductive substrate 1;

[0051] S2. Preparing the first carrier transport layer 2 on the transparent conductive substrate 1;

[0052] S3. Preparing the perovskite thin film 3 on the first carrier transport layer 2;

[0053] S4. Preparing the second carrier transport layer 4 on the perovskite thin film 3;

[0054] S5. Preparing the buffer layer 5 on the second carrier transport layer 4;

[0055] S6. Preparing the back electrode layer 6 on the buffer layer 5;

[0056] Among them, the preparation steps of the perovskite thin film 3 include:

[0057] Placing the perovskite precursor material and the additive 1-pyrenebutyric acid in a solvent, stirring until completely dissolved, and then filtering it 1-5 times with a 0.22 μm filter to finally obtain a clear yellow liquid (perovskite precursor solution). Then, the prepared perovskite precursor solution is coated on the upper surface of the first carrier transport layer 2 by methods such as spin coating, blade coating or slot die coating, and annealed to obtain the perovskite thin film 3 including the perovskite material and the additive 1-pyrenebutyric acid; the solvent is one or more of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), γ-butyrolactone (GBL), dimethylacetamide (DMA), N,N-dimethylpropyleneurea (DMPU), and acetonitrile.

[0058] Further, the concentration of the mixed cation perovskite in the perovskite precursor solution is 1-1.8 M, and the concentration of 1-pyrenebutyric acid is 0.1-1 mg / mL.

[0059] During the research, the applicant found that when the content of 1-pyrenebutanoic acid in the perovskite precursor solution is too low (less than 0.1 mg / mL), it is difficult to form a complete and effective modification layer on the surface and interface of the perovskite thin film during crystallization, resulting in increased charge recombination, limited open-circuit voltage and fill factor of the battery, and it is difficult to significantly improve the photoelectric conversion efficiency. When the concentration of 1-pyrenebutanoic acid in the perovskite precursor solution is too high (higher than 1.0 mg / mL), it will interfere with the growth of perovskite crystals, distort the crystal structure, and lead to a decline in the performance of perovskite solar cell devices.

[0060] Hereinafter, examples and comparative examples are given to more specifically illustrate the implementation manners of the present application.

[0061] Example 1

[0062] The preparation of the perovskite solar cell with optimized additive strategy in this example includes the following steps:

[0063] S1. Cleaning of the transparent conductive substrate 1: The FTO transparent conductive substrate 1 is ultrasonically treated with acetone and isopropyl alcohol for 25 min respectively, and the surface is dried with nitrogen; then it is subjected to ultraviolet ozone treatment for 10 min; among them, the power of ultrasonic cleaning is 100 Hz and the time is 15 min;

[0064] S2. Preparation of the first carrier transport layer 2 (hole transport layer): The NiOx dispersion is spin-coated on the cleaned FTO transparent conductive substrate 1, and the spin-coating conditions are: rotating at a low speed of 500 rpm for 3 s, rotating at a high speed of 4000 rpm for 30 s, and then annealing at 150 °C for 30 min to obtain the NiOx hole transport layer;

[0065] S3. Preparation of the perovskite thin film 3: Weigh 668.45 mg of lead iodide (PbI2), 236.89 mg of formamidinium iodide (FAI), and 18.84 mg of cesium iodide (CsI) and place them in a solvent (volume ratio DMF:DMSO = 4:1), and add the additive 1-pyrenebutanoic acid, stir until completely dissolved, and prepare a solution with a mixed cation perovskite concentration of 1.5 M and a 1-pyrenebutanoic acid concentration of 0.1 mg / mL. Then use a 0.22 μm filter to filter it three times to obtain the perovskite precursor solution (a clear yellow liquid); spin-coat the obtained perovskite precursor solution on the NiOx hole transport layer at 4000 rpm for 40 s, and anneal at a temperature of 100 °C for 30 min to obtain the perovskite thin film 3;

[0066] S4. Preparation of the second carrier transport layer 4 (electron transport layer): Deposit a C layer with a thickness of 30 nm on the perovskite thin film 3 by vacuum evaporation 60 to obtain the electron transport layer;

[0067] S5. Preparation of buffer layer 5: Place the component obtained in step S4 in a vacuum coating machine, and deposit a BCP layer with a thickness of 10 nm on the electron transport layer by evaporation to obtain buffer layer 5;

[0068] S6. Preparation of back electrode layer 6: Place the component obtained in step S5 in a vacuum coating machine, and evaporate a 100-nm metal Cu electrode on buffer layer 5 by thermal evaporation to obtain a perovskite solar cell, denoted as T1.

[0069] Example 2

[0070] Compared with Example 1, the difference in this example is that in the prepared perovskite precursor solution, the concentration of 1-pyrenebutanoic acid is 1 mg / mL.

[0071] Denote the obtained perovskite solar cell as T2.

[0072] Comparative Example 1

[0073] Compared with Example 1, the difference in this example is that 1-pyrenebutanoic acid is not added to the perovskite precursor solution.

[0074] Denote the obtained perovskite solar cell as D1.

[0075] Comparative Example 2

[0076] Compared with Example 1, the difference in this example is that in the prepared perovskite precursor solution, the concentration of 1-pyrenebutanoic acid is 0.08 mg / mL.

[0077] Denote the obtained perovskite solar cell as D2.

[0078] Comparative Example 3

[0079] Compared with Example 1, the difference in this example is that in the prepared perovskite precursor solution, the concentration of 1-pyrenebutanoic acid is 1.1 mg / mL.

[0080] Denote the obtained perovskite solar cell as D3.

[0081] Characterize the perovskite thin film prepared in step S3 of Example 1 and the perovskite thin film prepared in step S3 of Comparative Example 1 by scanning electron microscopy, and the results are as Figure 2 shown, Figure 2 in which (a) is the SEM image of the perovskite thin film in Comparative Example 1, and (b) is the SEM image of the perovskite thin film in Example 1. From Figure 2As can be seen from (a) and (b) in the figure, without the optimization of the additive (1-pyrenebutyric acid), the grains of the perovskite film are small and its crystallinity is poor. After introducing the additive 1-pyrenebutyric acid, the size of the perovskite grains has been significantly improved, reducing the grain boundary area, indicating that the introduction of the additive 1-pyrenebutyric acid improves the quality of the perovskite film and reduces the defect density in the film.

[0082] Perform J-V tests on TI~T2 and D1~D3:

[0083] Using a solar simulator, perform a standard solar irradiance calibration and perform J-V tests on the devices obtained from the above examples and comparative examples with an area of 10.5 cm 2 including the power conversion efficiency (PCE), fill factor (FF), open-circuit voltage (Voc), and short-circuit current (Jsc). Set the starting voltage to 8.5 V, the cut-off voltage to -0.1 V, and the test step to 0.2 V. The test results are retained to two decimal places, and the test results are shown in Table 1:

[0084] Table 1. J-V test results of TI~T2 and D1~D3

[0085] Device Voc (V) FF (%) PCE (%) <![CDATA[Jsc(mA·cm -2 )]]> T1 8.144 79.7 21.61 3.33 T2 8.058 74.5 19.75 3.29 D1 7.674 76.2 19.18 3.28 D2 8.077 73.7 18.99 3.19 D3 7.762 71.95 18.37 3.29

[0086] Analyzing the data in Table 1 and comparing the performance test results of T1~T2 with D1, it can be seen that compared with the performance of the perovskite solar cell optimized by the additive (1-pyrenebutyric acid) strategy of the present invention and the existing perovskite solar cell without adding the additive 1-pyrenebutyric acid, the performance of the perovskite solar cell device of the present invention has been significantly improved, further verifying that the 1-pyrenebutyric acid molecule can interact with the perovskite molecule during the perovskite crystallization process and improve the device performance by regulating the perovskite crystallization process, improving the crystal quality and interface properties, etc. Comparing the performance test results of T1~T2, D1 with D2~D3, it can be clearly seen that when the 1-pyrenebutyric acid in the perovskite precursor solution is less than 0.1 mg / mL or higher than 1.0 mg / mL, the performance of the obtained device has no obvious improvement and even shows a downward trend. This is because when the 1-pyrenebutyric acid in the perovskite precursor solution is too low (less than 0.1 mg / mL), it is difficult to form a complete and effective modification layer on the surface and interface of the perovskite film, resulting in increased charge recombination, limited open-circuit voltage and fill factor of the battery, and it is difficult to significantly improve the power conversion efficiency. When the concentration of 1-pyrenebutyric acid in the perovskite precursor solution is too high (higher than 1.0 mg / mL), it will interfere with the growth of perovskite crystals, causing crystal structure distortion and resulting in a decline in the performance of perovskite solar cell devices.

[0087] The above embodiments are only for explaining the technical concept and features of the present invention, and the purpose is to enable those who are familiar with this technology to understand the content of the present invention and implement it accordingly, and shall not be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the spirit essence of the present invention shall be covered within the protection scope of the present invention.

Claims

1. A perovskite solar cell with optimized additive strategy, which sequentially includes a transparent conductive substrate, a first carrier transport layer, a perovskite thin film, a second carrier transport layer, a buffer layer and a back electrode layer from bottom to top, characterized in that, The perovskite film includes a perovskite material and an additive, the perovskite material is a mixed-cation perovskite, and the additive is 1-pyrenebutyric acid.

2. The perovskite solar cell according to claim 1, wherein The mixed cation perovskite is ABX3, where the A site includes, but is not limited to, Cs + , MA + , FA + or one or more of them; the B site includes, but is not limited to, Pb 2+ , Sn 2+ , Ge2+ or one or more of them; the X site includes, but is not limited to, I - , Br - , Cl - or one or more of them.

3. The perovskite solar cell according to claim 1, wherein The mixed cation perovskite includes, but is not limited to, FA x MA 1-x PbI3, FA x Cs 1-x PbI3, MAPb x Sn 1-x I y Br 3-y , FA x MA 1-x PbI y Br 3-y or one or more of the above.

4. The perovskite solar cell according to claim 1, wherein The first charge transport layer is an electron transport layer or a hole transport layer, and the second charge transport layer corresponds to the first charge transport layer; when the first charge transport layer is an electron transport layer, the second charge transport layer is a hole transport layer; when the first charge transport layer is a hole transport layer, the second charge transport layer is an electron transport layer.

5. The perovskite solar cell according to claim 1, characterized in that, The transparent conductive substrate is ITO conductive glass or FTO conductive glass.

6. The perovskite solar cell according to claim 4, wherein The hole transport layer is a p-type inorganic semiconductor material and / or a p-type organic semiconductor material, including but not limited to poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], 2,2',7,7'-tetrakis[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene, poly(3,4-ethylenedioxythiophene):polystyrenesulfonate, polyvinylcarbazole, 4-butyl-N,N-diphenylaniline homopolymer, [2-(9H-carbazol-9-yl)ethyl]phosphonic acid, [3-(9H-carbazol-9-yl)ethyl]phosphonic acid, [4-(9H-carbazol-9-yl)ethyl]phosphonic acid, CuI, CuSCN, or one or more of them.

7. The perovskite solar cell according to claim 4, characterized in that, The electron transport layer is an n-type inorganic semiconductor material and / or an n-type organic semiconductor material, including but not limited to one or more of TiO2, SnO2, C 60 or PCBM.

8. The perovskite solar cell according to claim 1, characterized in that, The buffer layer is one of MoO x , V2O5, BCP or SnO2.

9. The perovskite solar cell according to claim 1, characterized in that, The back electrode layer is one of Au, Ag, Cu, or a carbon electrode.

10. The preparation method of the perovskite solar cell according to any one of claims 1 to 9, characterized in that, Comprising the following steps: S1. Cleaning the transparent conductive substrate; S2. Preparing a first charge transport layer on the transparent conductive substrate; S3. Preparing a perovskite film on the first charge transport layer; S4. Preparing a second charge transport layer on the perovskite film; S5. Preparing a buffer layer on the second charge transport layer; S6. Preparing a back electrode layer on the buffer layer; Wherein, the preparation steps of the perovskite film include: Placing a perovskite precursor material and an additive 1-pyrenebutyric acid in a solvent to obtain a perovskite precursor solution, and then coating it on the upper surface of the first charge transport layer and annealing to obtain a perovskite film including a perovskite material and an additive 1-pyrenebutyric acid; the solvent is one or more of N,N-dimethylformamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, γ-butyrolactone, dimethylacetamide, N,N-dimethylpropyleneurea, and acetonitrile, and the coating method is one of spin coating, blade coating, or slot coating.

11. According to the preparation method of claim 10, the concentration of the mixed-cation perovskite in the perovskite precursor solution is 1 to 1.8 M, and the concentration of 1-pyrenebutyric acid is 0.1 to 1 mg / mL.

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