A perovskite thin film and a preparation method thereof, and a perovskite solar cell and a preparation method thereof

Abstract

The application belongs to the technical field of solar cells, and particularly relates to a perovskite film and a preparation method thereof, a perovskite solar cell and a preparation method thereof. The preparation method provided by the application comprises the following steps: coating an interface treatment solution on the surface of a hole transport layer, wherein the interface treatment solution comprises a polyelectrolyte, an organic ammonium salt and an organic solvent; annealing the obtained interface treatment coating layer; and coating a perovskite precursor solution on the surface of the obtained interface layer to prepare a perovskite layer. According to the application, the interface is only treated before the perovskite layer is prepared, so that a perovskite film with a compact structure and few grain boundaries can be obtained, and the non-radiative recombination of the perovskite film is obviously inhibited, thereby effectively improving the photoelectric conversion efficiency and stability of the perovskite solar cell.

Description

Technical Field

[0001] This invention belongs to the field of solar cell technology, specifically relating to a perovskite thin film and its preparation method, and a perovskite solar cell and its preparation method. Background Technology

[0002] Currently, organic-inorganic hybrid perovskite solar cells (PSCs) have become one of the most promising photovoltaic candidate materials due to their advantages of low cost of solution fabrication and excellent photoelectric performance. In the past decade, the photoelectric conversion efficiency of PSCs has increased from 3.8% to over 25%, which has aroused great interest among researchers in practical applications.

[0003] Due to the sensitivity of perovskite to light, heat, and humidity, improving the efficiency and stability of perovskite solar cells (PSCs) is challenging for commercialization. The fabrication of high-quality perovskite thin films is a crucial foundation for achieving efficient and stable perovskite solar cells. However, since defects in perovskite films are generally concentrated at interfaces and grain boundaries, to prepare perovskite films with low defect density and good crystallinity, it is often necessary to introduce passivating molecules into the perovskite precursor solution and perform passivation treatments at the top and bottom interfaces of the perovskite film within the perovskite solar cell structure. This significantly increases the complexity of PSC fabrication and results in perovskite solar cells with poor photoelectric conversion performance. Summary of the Invention

[0004] The purpose of this invention is to provide a perovskite thin film and its preparation method, and a perovskite solar cell and its preparation method. The preparation method provided by this invention only requires interface treatment before preparing the perovskite layer, which can obtain a perovskite thin film with a dense structure and few grain boundaries. The preparation method is simple and can effectively improve the photoelectric conversion efficiency and stability of perovskite solar cells.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for preparing perovskite thin films, comprising the following steps:

[0007] An interface treatment solution is coated on the surface of the hole transport layer to obtain an interface treatment coating; the interface treatment solution includes a polyelectrolyte, an organic ammonium salt, and an organic solvent.

[0008] The interface treatment coating is annealed to obtain the interface layer;

[0009] A perovskite layer is prepared by coating the surface of the interface layer with a perovskite precursor solution to obtain the perovskite film. The solvent in the perovskite precursor solution is a solvent capable of dissolving the polyelectrolyte and the organic ammonium salt. A perovskite film is formed on the surface of the hole transport layer. The perovskite film includes an organic ammonium salt buried interface layer, a perovskite layer, and a polyelectrolyte interface surface layer stacked sequentially.

[0010] Preferably, the polyelectrolyte comprises one or more of poly(9,9-bis(3'-(N,N-dimethyl)-N-ethylaminopropyl-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)) dibromide (PFN-Br), poly(9,9-bis(3'-(N,N-dimethyl)-N-ethylaminopropyl-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)) diiodide (PFN-I), a compound with the structure shown in Formula 1 (PEIE), and a compound with the structure shown in Formula 2 (P3CT-K);

[0011]

[0012] Preferably, the organic ammonium salt comprises one or more of phenethylamine iodine (PEAI), ethyltrimethylammonium bromide (HTAB), butylated diamine iodine (BDADI), octylamine chloride (OACl), tert-butylamine hydroiodate (t-BAI), tert-butylammonium chloride (t-BACl), phenethylammonium chloride (PEACl), 1,4-phenylenediamine hydroiodate (PhDADI), benzylamine iodide (PMAI), 1,4-phenylenediamine iodine, guanidinium hydrobromide (GABr), and guanidinium thiocyanate (GuSCN).

[0013] Preferably, in the interface treatment solution, the mass ratio of the polyelectrolyte to the organic ammonium salt is 1:(1-20).

[0014] Preferably, the annealing temperature is room temperature to 150°C, and the annealing holding time is 5 to 10 minutes.

[0015] Preferably, the coating is replaced by the following steps:

[0016] A first interface treatment solution is first coated on the surface of the hole transport layer to obtain a first interface treatment coating; the first interface treatment solution includes the polyelectrolyte and an organic solvent.

[0017] A second interface treatment solution is applied to the surface of the first interface treatment coating to obtain a second interface treatment coating; the second interface treatment solution includes an organic ammonium salt and an organic solvent.

[0018] The first interface treatment coating and the second interface treatment coating, which are stacked together, form the interface treatment coating.

[0019] The present invention provides a perovskite thin film prepared by the preparation method described above, wherein the perovskite thin film comprises an organic ammonium salt buried interface layer, a perovskite layer and a polyelectrolyte interface surface layer stacked sequentially.

[0020] Preferably, the thickness of the organic ammonium salt buried interface layer and the polyelectrolyte interface surface layer are independently 0.5 to 30 nm.

[0021] The present invention provides a perovskite solar cell, comprising a conductive substrate and a hole transport layer, a perovskite thin film, an electron transport layer, an interface buffer layer, and an electrode sequentially stacked on the surface of the conductive substrate, wherein the perovskite thin film is the perovskite thin film described in the above technical solution.

[0022] This invention provides a method for preparing the perovskite solar cell described above, comprising the following steps:

[0023] A hole transport layer is prepared on the surface of the conductive substrate;

[0024] A perovskite thin film is prepared on the surface of the hole transport layer according to the method described above.

[0025] An electron transport layer is prepared on the surface of the perovskite thin film;

[0026] An interface buffer layer is prepared on the surface of the electron transport layer;

[0027] An electrode is fabricated on the surface of the interface buffer layer to obtain the perovskite solar cell.

[0028] This invention provides a method for preparing a perovskite thin film, comprising the following steps: coating an interface treatment solution onto the surface of a hole transport layer to obtain an interface treatment coating; the interface treatment solution includes a polyelectrolyte, an organic ammonium salt, and an organic solvent; annealing the interface treatment coating to obtain the interface layer; coating the surface of the interface layer with a perovskite precursor solution to prepare a perovskite layer, thereby obtaining the perovskite thin film, wherein the solvent in the perovskite precursor solution is a solvent capable of dissolving the polyelectrolyte and the organic ammonium salt; and obtaining a perovskite thin film formed on the surface of the hole transport layer, wherein the perovskite thin film comprises an organic ammonium salt buried interface layer, a perovskite layer, and a polyelectrolyte interface surface layer sequentially stacked. The preparation method provided by this invention involves treating the hole transport layer surface with an interface treatment solution to prepare an interface layer before preparing the perovskite layer on the hole transport layer surface. After coating with a perovskite precursor solution, the polyelectrolyte in the interface layer, the metal salt in the perovskite precursor solution, and the solvent in the perovskite precursor solution form an intermediate ligand phase. This phase assists the perovskite precursor solution in obtaining a dense perovskite layer with few grain boundaries and pores. Simultaneously, due to the low density of the polyelectrolyte, it spontaneously accumulates on the upper surface of the perovskite layer, forming a polyelectrolyte interface. In the surface layer, the functional groups in the polyelectrolyte can passivate surface defects of the perovskite layer, and the hydrophobic aliphatic chain structure of the polyelectrolyte can protect the perovskite, improving the stability of the perovskite solar cell. Organic amine salts spontaneously accumulate at the bottom interface of the perovskite layer, forming an organic ammonium salt buried interface layer, which passivates defects at the bottom interface of the perovskite layer. Simultaneously, it forms a band structure more conducive to carrier transport at the interface where the perovskite and hole transport layer meet, reducing carrier recombination at this interface. Therefore, the preparation method provided by this invention only requires interface treatment before preparing the perovskite layer, resulting in a dense perovskite film with few grain boundaries. Non-radiative recombination of the perovskite film is also significantly suppressed, effectively improving the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0029] This invention provides a perovskite thin film prepared by the method described above. The perovskite thin film comprises an organic ammonium salt buried interface layer, a perovskite layer, and a polyelectrolyte interface layer stacked sequentially. This invention forms a polyelectrolyte interface layer on the upper surface of the perovskite layer and a buried interface layer on the lower surface of the perovskite layer, reducing defects in the perovskite thin film and enabling the perovskite solar cell to achieve a photoelectric conversion efficiency exceeding 23%, while also significantly improving device stability. Attached Figure Description

[0030] Figure 1 Scanning electron microscope images of the perovskite thin film prepared in Example 1, Comparative Example 1, and Comparative Example 2 of the present invention.

[0031] Figure 2This is a time-of-flight secondary mass spectrometry characterization of the perovskite thin film prepared in Example 1 of the present invention;

[0032] Figure 3 Transient fluorescence spectra and time-resolved fluorescence spectra of the perovskite films prepared in Example 1, Comparative Example 1, and Comparative Example 2 of this invention.

[0033] Figure 4 Performance characterization diagrams of the perovskite solar cells prepared in Example 1, Comparative Example 1, and Comparative Example 2 of this invention.

[0034] Figure 5 This is a performance comparison chart of the perovskite solar cell (denoted as Target device) prepared in Example 4 of the present invention and the perovskite solar cell (denoted as Control device) prepared in Comparative Example 3.

[0035] Figure 6 This is a performance comparison diagram of the perovskite thin-film solar cell prepared in Example 2 of the present invention and the perovskite solar cell prepared in Comparative Example 1. Detailed Implementation

[0036] This invention provides a method for preparing perovskite thin films, comprising the following steps:

[0037] An interface treatment solution is coated on the surface of the hole transport layer to obtain an interface treatment coating; the interface treatment solution includes a polyelectrolyte, an organic ammonium salt, and an organic solvent.

[0038] The interface treatment coating is annealed to obtain the interface layer;

[0039] A perovskite layer is prepared by coating the surface of the interface layer with a perovskite precursor solution to obtain the perovskite film. The solvent in the perovskite precursor solution is a solvent capable of dissolving the polyelectrolyte and the organic ammonium salt. A perovskite film is formed on the surface of the hole transport layer. The perovskite film includes an organic ammonium salt buried interface layer, a perovskite layer, and a polyelectrolyte interface surface layer stacked sequentially.

[0040] In this invention, unless otherwise specified, all raw materials / components used in the preparation are commercially available products well known to those skilled in the art.

[0041] An interface treatment solution is coated on the surface of the hole transport layer to obtain an interface treatment coating; the interface treatment solution includes a polyelectrolyte, an organic ammonium salt, and an organic solvent.

[0042] In this invention, the polyelectrolyte preferably includes one or more of PFN-Br, PFN-I, compounds with the structure shown in Formula 1, and compounds with the structure shown in Formula 2;

[0043]

[0044] In this invention, the compound with the structure shown in Formula 1 is called polyethylenimine, abbreviated as PEIE. In Formula 1, x, y, and z represent the degree of polymerization.

[0045] In this invention, the English name of the compound with the structure shown in Formula 2 is: potassium poly[3-(4-carboxylatebutyl)thiophene, abbreviated as P3CT-K. In Formula 2, n represents the degree of polymerization.

[0046] In this invention, the polyelectrolyte is more preferably PFN-Br and / or PFN-I, and even more preferably PFN-Br.

[0047] In this invention, the organic ammonium salt preferably includes one or more of PEAI, HTAB, BDADI, OACl, t-BAI, t-BACl, PEACl, PhDADI, PMAI, 1,4-phenylenediamine iodine, GABr, and GuSCN, more preferably phenylethylamine iodine (PEAI) and / or ethyltrimethylammonium bromide (HTAB), and even more preferably PEAI.

[0048] In this invention, the mass ratio of the polyelectrolyte to the organic ammonium salt in the interface treatment solution is preferably 1:(1-20), more preferably 1:10.

[0049] In this invention, the organic solvent is preferably methanol or isopropanol.

[0050] In this invention, the mass concentration of the polyelectrolyte in the interface treatment solution is preferably 1 mg / mL.

[0051] In this invention, the mass concentration of the organic ammonium salt in the interface treatment solution is preferably 10 mg / mL.

[0052] In this invention, the temperature of the interface treatment solution is preferably 50°C during the coating process.

[0053] In this invention, the coating is preferably performed by spin coating, slot coating, blade coating, screen printing, or inkjet printing. When the coating is spin coating, the spin coating speed is preferably 2000–5000 rpm. The spin coating time is preferably 30 seconds.

[0054] As one or more embodiments of the present invention, the coating is replaced by the following steps:

[0055] A first interface treatment solution is first coated on the surface of the hole transport layer to obtain a first interface treatment coating; the first interface treatment solution includes the polyelectrolyte and an organic solvent.

[0056] A second interface treatment solution is applied to the surface of the first interface treatment coating to obtain a second interface treatment coating; the second interface treatment solution includes an organic ammonium salt and an organic solvent.

[0057] The first interface treatment coating and the second interface treatment coating, which are stacked together, form the interface layer.

[0058] In this invention, a first interface treatment solution is first coated onto the surface of the hole transport layer to obtain a first interface treatment coating; the first interface treatment solution includes the polyelectrolyte and an organic solvent. In this invention, the organic solvent is preferably methanol; the mass concentration of the polyelectrolyte in the first interface treatment solution is preferably 1 mg / mL. In this invention, the temperature of the first interface treatment solution during the first coating is preferably 50°C. In this invention, the first coating is preferably spin-coating, and the spin-coating speed is preferably 2000–5000 rpm. The spin-coating time is preferably 30 s.

[0059] After obtaining the first interface treatment coating, the present invention applies a second interface treatment solution to the surface of the first interface treatment coating to obtain a second interface treatment coating; the second interface treatment solution comprises an organic ammonium salt and an organic solvent. In the present invention, the organic solvent is preferably methanol, and the mass concentration of the organic ammonium salt in the second interface treatment solution is preferably 10 mg / mL. In the present invention, the temperature of the second interface treatment solution during the second coating is preferably 50°C. In the present invention, the second coating is preferably spin-coating, and the spin-coating speed is preferably 2000–5000 rpm. The spin-coating time is preferably 30 s.

[0060] In this invention, the first interface treatment coating and the second interface treatment coating stacked together form the interface layer.

[0061] After obtaining the interface treatment coating, the present invention performs an annealing treatment on the interface treatment coating to obtain the interface layer.

[0062] In this invention, the annealing temperature is preferably room temperature to 150°C, more preferably 100°C, and the annealing holding time is preferably 5 to 10 minutes, more preferably 5 minutes.

[0063] After obtaining the interface layer, the present invention coats the surface of the interface layer with a perovskite precursor solution to prepare a perovskite layer, thereby obtaining the perovskite film. The solvent in the perovskite precursor solution is a solvent capable of dissolving the polyelectrolyte and the organic ammonium salt. A perovskite film is formed on the surface of the hole transport layer, and the perovskite film includes an organic ammonium salt buried interface layer, a perovskite layer and a polyelectrolyte interface surface layer stacked sequentially.

[0064] In this invention, the method for preparing the perovskite layer preferably includes a two-step method and a one-step method.

[0065] In this invention, the two-step method is preferably carried out with reference to the perovskite layer preparation method described in "Surface Passivation of Perovskite Film for Efficient Solar Cells" (Qi Jiang, Yang Zhao, Xingwang Zhang, Xiaolei Yang, Yong Chen1, Zema Chu, Qiufeng Ye, Xingxing Li, Zhigang Yin and Jingbi You. Nat. Photonics 2019, 13, 460-466.). The one-step process is preferably carried out in accordance with the preparation method of the perovskite layer described in "Surface Reaction for Efficient and Stable Inverted Perovskite Solar Cells" (Jiang, Q.; Tong, J.; Xian, Y.; Kerner, RA; Dunfield, SP; Xiao, C.; Scheidt, RA; Kuciauskas, D.; Wang, X.; Hautzinger, MP; Tirawat, R.; Beard, MC; Fenning, DP; Berry, JJ; Larson, BW; Yan, Y.; Zhu, K., Surface Reaction for Efficient and Stable Inverted Perovskite Solar Cells. Nature 2022. DOI: 10.1038 / s41586-022-05268-x).

[0066] When the perovskite layer is prepared by the two-step method of the present invention, the perovskite precursor solution includes a PbI2 solution and a mixed solution of formamidinium iodide (FAI), methylamine chloride (MACl), and methylamine chloride (MAI).

[0067] In this invention, the two-step method preferably includes the following steps:

[0068] A PbI2 solution is coated onto the surface of the interface layer to obtain a PbI2 solution layer;

[0069] A mixed solution of FAI, MACl, and MAI was coated onto the surface of the PbI2 solution layer, followed by annealing to obtain the perovskite layer.

[0070] This invention involves coating a PbI2 solution onto the surface of the interface layer to obtain a PbI2 solution layer. In this invention, the solvent in the PbI2 solution is preferably N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), with a volume ratio of DMF to DMSO of 9:1, and the mass concentration of the PbI2 solution is preferably 691.5 mg / mL. The coating method is preferably spin coating, the spin coating speed is preferably 5000–15000 rpm, and the spin coating time is preferably 30 s. Subsequently, it is annealed on a hot plate at 70°C for 1 min.

[0071] After obtaining the PbI2 solution layer, this invention coats the surface of the PbI2 solution layer with a mixed solution of FAI, MAI, and MACl. After obtaining the mixed solution of FAI, MAI, and MACl, an annealing treatment is performed to obtain the perovskite layer. In this invention, the solvent in the mixed solution of FAI, MAI, and MACl is preferably isopropanol (IPA). The mass concentration of FAI in the mixed solution of FAI, MAI, and MACl is preferably 90 mg / mL, the mass concentration of MAI is preferably 6.39 mg / mL, and the mass concentration of MACl is preferably 9 mg / mL. The coating is preferably spin-coating, the spin-coating speed is preferably 2000–5000 rpm, and the spin-coating time is preferably 30 s. The annealing temperature is preferably 150°C, and the annealing holding time is preferably 15 min. Note that this step needs to be performed outdoors, with an outdoor humidity requirement of 20%–40% relative humidity (RH).

[0072] In this invention, after coating the interface layer with the PbI2 solution to obtain a PbI2 solution layer, the solvent in the PbI2 solution layer dissolves the polyelectrolyte in the interface layer. The polyelectrolyte forms an intermediate ligand phase with the PbI2-DMSO, which assists in the reaction with FAI, MAI, and MACl to obtain a dense perovskite layer with few pores. During the formation of the perovskite layer, the polyelectrolyte gradually accumulates on the surface of the perovskite layer, forming a polyelectrolyte interface surface layer. The organic ammonium salt is located on the bottom surface of the perovskite layer, forming an organic ammonium salt buried interface layer.

[0073] In this invention, the perovskite precursor solution prepared using a one-step method comprises a mixed solution of CsI, RbI, MABr, FAI, PbI2, and PbBr2. Specifically, the one-step method preferably includes the following steps:

[0074] A mixed solution of CsI, RbI, MABr, FAI, PbI2, and PbBr2 is coated onto the surface of the interface layer to obtain a mixed solution layer of CsI, RbI, MABr, FAI, PbI2, and PbBr2. The mixed solution layer of CsI, RbI, MABr, FAI, PbI2, and PbBr2 is then annealed to obtain the perovskite layer.

[0075] In this invention, the solvent in the FAI, MAI, and PbI2 mixed solution is preferably a blend of DMF and DMSO (volume ratio DMF:DMSO = 4:1). The preferred mass concentrations of CsI, RbI, MABr, FAI, PbI2, and PbBr2 in the mixed solution are: CsI 19.5 mg / mL, RbI 15.9 mg / mL, MABr 8.4 mg / mL, FAI 219.5 mg / mL, PbI2 656.9 mg / mL, and PbBr2 27.5 mg / mL. The coating process is preferably spin coating, with the spin coating speed preferably being 1000 rpm for 10 seconds in the first step and 3000 rpm for 30 seconds in the second step. In the second step of the spin coating process, 150 μL of the anti-solvent chlorobenzene (CB) is added dropwise. The preferred annealing temperature is 100°C, and the preferred annealing time is 10 minutes.

[0076] In this invention, after coating the interface layer with the mixed solution of CsI, RbI, MABr, FAI, PbI2, and PbBr2, the solvent in the mixed solution of CsI, RbI, MABr, FAI, PbI2, and PbBr2 perovskite precursors dissolves the polyelectrolyte in the interface layer. The polyelectrolyte, together with the perovskite precursor components and the DMSO solvent, forms an intermediate ligand phase, resulting in a dense perovskite layer with few pores. During the formation of the perovskite layer, the polyelectrolyte gradually accumulates on the surface of the perovskite layer, forming a polyelectrolyte interface surface layer. The organic ammonium salt is located on the bottom surface of the perovskite layer, forming an organic ammonium salt buried interface layer.

[0077] The present invention provides a perovskite thin film prepared by the preparation method described above, wherein the perovskite thin film comprises an organic ammonium salt buried interface layer, a perovskite layer and a polyelectrolyte interface surface layer stacked sequentially.

[0078] In this invention, the thickness of the organic ammonium salt buried interface layer is preferably 3 to 30 nm.

[0079] In this invention, the thickness of the polyelectrolyte interface layer is preferably 3 to 30 nm.

[0080] In this invention, the thickness of the perovskite layer is preferably 600-1000 nm.

[0081] The present invention provides a perovskite solar cell, comprising a conductive substrate and a hole transport layer, a perovskite thin film, an electron transport layer, an interface buffer layer, and an electrode sequentially stacked on the surface of the conductive substrate, wherein the perovskite thin film is the perovskite thin film described in the above technical solution.

[0082] In this invention, the conductive substrate is preferably indium tin oxide (ITO).

[0083] In this invention, the hole transport layer is preferably made of poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), a self-assembled monolayer of [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACz), or nickel oxide (NiOx).

[0084] In this invention, the thickness of the hole transport layer is preferably 5 to 10 nm.

[0085] In this invention, the preferred material for the electron transport layer is methyl (6,6)-phenyl-C61-butyrate (PCBM) or C... 60 .

[0086] In this invention, the thickness of the electron transport layer is preferably 25-50 nm.

[0087] In this invention, the material of the interface buffer layer is preferably bath copper ether (BCP).

[0088] In this invention, the thickness of the interface buffer layer is preferably 5 to 10 nm.

[0089] In this invention, the electrode is preferably made of elemental copper.

[0090] In this invention, the thickness of the electrode is preferably 100 nm.

[0091] This invention provides a method for preparing the perovskite solar cell described above, comprising the following steps:

[0092] A hole transport layer is prepared on the surface of the conductive substrate;

[0093] A perovskite thin film is prepared on the surface of the hole transport layer according to the method described above, thereby forming a perovskite layer.

[0094] An electron transport layer is prepared on the surface of the perovskite layer;

[0095] An interface buffer layer is prepared on the surface of the electron transport layer;

[0096] An electrode is fabricated on the surface of the interface buffer layer to obtain the perovskite solar cell.

[0097] The present invention prepares a hole transport layer on the surface of the conductive substrate.

[0098] Before preparing the hole transport layer, the present invention preferably performs a sequential cleaning and ultraviolet-ozone (UV-O3) treatment on the conductive substrate.

[0099] In this invention, the cleaning process preferably includes the following steps: ultrasonically cleaning the conductive substrate sequentially with a cleaning agent, ultrasonically cleaning with deionized water, ultrasonically cleaning with acetone, and ultrasonically cleaning with isopropanol. The ultrasonic cleaning time with the cleaning agent is preferably 15 minutes, the ultrasonic cleaning time with deionized water is preferably 15 minutes, the ultrasonic cleaning time with acetone is preferably 15 minutes, and the ultrasonic cleaning time with isopropanol is preferably 15 minutes.

[0100] In this invention, the UV-O3 treatment time is 15 minutes. This invention does not have special requirements regarding the specific implementation process of the UV-O3 treatment. Preferably, this invention uses the UV-O3 treatment to remove residual organic matter on the surface of the conductive substrate and improve the work function.

[0101] In this invention, the method for preparing the hole transport layer preferably includes the following steps:

[0102] Hole transport layer material is dissolved in an organic solvent to obtain a hole transport layer precursor solution; the hole transport layer precursor solution is coated on the surface of a conductive substrate to obtain a hole transport layer precursor solution layer; the hole transport layer precursor solution layer is preferably annealed to obtain the hole transport layer.

[0103] In this invention, the hole transport layer material is preferably PTAA, MeO-2PACz, or NiOx. For the PTAA hole transport layer, the solvent is preferably toluene, with a preferred concentration of 2 mg / mL; for the MeO-2PACz hole transport layer, the solvent is preferably isopropanol, with a preferred concentration of 0.5 mg / mL. The coating process is preferably spin-coating, with a preferred spin-coating speed of 2000–5000 rpm and a preferred spin-coating time of 30 seconds.

[0104] After obtaining the hole transport layer precursor solution layer, the present invention preferably anneals the hole transport layer precursor solution layer to obtain the hole transport layer. The annealing temperature is preferably 120°C, and the annealing time is preferably 10 minutes.

[0105] After obtaining the hole transport layer, the present invention prepares the perovskite thin film on the surface of the hole transport layer according to the perovskite thin film preparation method described above.

[0106] In this invention, the hole transport layer is made of PTAA, which has hydrophobic properties. By using the above technical solution, an interface layer is prepared on the surface of the hole transport layer, and then a perovskite layer is prepared on the surface of the interface layer, which can effectively improve the wettability of the perovskite layer on the surface of the hole transport layer.

[0107] The perovskite thin film is obtained, and an electron transport layer is prepared on the surface of the perovskite thin film in this invention.

[0108] In this invention, the method for preparing the electron transport layer preferably includes the following steps:

[0109] PCBM is dissolved in an organic solvent to obtain an electron transport layer precursor solution; the electron transport layer precursor solution is coated onto the surface of the perovskite layer and then annealed. In this invention, the organic solvent is preferably chlorobenzene. The mass concentration of the electron transport layer precursor solution is preferably 20 mg / mL. In this invention, the coating is preferably spin-coating, the spin-coating speed is preferably 1000–5000 rpm, and the spin-coating time is preferably 30 s. Alternatively, C can be deposited using vacuum deposition. 60 The electron transport layer, preferably with a thickness of 25–50 nm, has a deposition rate of [missing information]. No thermal annealing is required after deposition.

[0110] After obtaining the electron transport layer, the present invention prepares an interface buffer layer on the surface of the electron transport layer.

[0111] In this invention, the method for preparing the interface buffer layer preferably includes the following steps:

[0112] BCP is dissolved in an organic solvent to obtain an interface buffer layer precursor solution; the interface buffer layer precursor solution is coated onto the surface of the electron transport layer and then annealed. In this invention, the organic solvent is preferably ethanol. The mass concentration of the interface buffer layer precursor solution is preferably 1 mg / mL. In this invention, the coating is preferably spin-coating, the spin-coating speed is preferably 2000–5000 rpm, and the spin-coating time is preferably 30 s. Alternatively, the BCP interface buffer layer can be deposited by vacuum deposition, with a thickness of 5–10 nm and a deposition rate of [missing information]. No thermal annealing is required after deposition.

[0113] After obtaining the interface buffer layer, the present invention prepares an electrode on the surface of the interface buffer layer to obtain the perovskite solar cell.

[0114] In this invention, the electrode is preferably prepared by vacuum evaporation. The specific implementation process of the vacuum evaporation is not particularly important. Preferably, the vacuum evaporation is performed in a vacuum evaporation apparatus.

[0115] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the accompanying drawings and embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0116] Example 1

[0117] The ITO transparent conductive substrate was cleaned by ultrasonic cleaning for 15 minutes each using glass cleaner, deionized water, acetone, and isopropanol.

[0118] The cleaned ITO transparent conductive substrate was treated with UV-O3 for 15 minutes to remove residual organic matter on the surface of the transparent ITO conductive substrate and improve its work function.

[0119] PTAA was dissolved in toluene to obtain a hole transport layer precursor solution with a mass concentration of 2 mg / mL. The hole transport layer precursor solution was spin-coated onto the surface of an ITO conductive substrate at a spin speed of 5000 rpm for 30 s to obtain a hole transport layer precursor solution layer. Subsequently, it was annealed at 120 °C for 10 min to obtain the hole transport layer.

[0120] PFN-Br and phenylethylammonium iodide (PEAI) were dissolved in methanol at a mass ratio of 1:10 to obtain an interface treatment solution with a total mass concentration of 11 mg / mL. The interface treatment solution was heated and stirred on a hot plate at 50 °C, and then spin-coated onto the surface of the hole transport layer at a spin speed of 5000 rpm for 30 s to obtain an interface treatment solution layer. Subsequently, the solution was annealed at 100 °C for 5 min to obtain the interface layer.

[0121] PbI2 was dissolved in DMF and DMSO to obtain a PbI2 solution. The preferred mass concentration of the PbI2 solution was 691.5 mg / mL. The solvent was a mixture of DMF and DMSO (volume ratio DMF:DMSO = 9:1). The PbI2 solution was spin-coated onto the surface of the interface layer at a speed of 1500 rpm for 30 s. Then, it was annealed on a hot plate at 70°C for 1 min to obtain a PbI2 coating.

[0122] FAI, MAI, and MACl are co-dissolved to obtain a mixed solution. The solvent in this solution is preferably isopropanol. The preferred mass concentrations of FAI, MAI, and MACl in the mixed solution are 90 mg / mL, 6.39 mg / mL, and 9 mg / mL. The FAI, MAI, and MACl solution is then spin-coated onto the surface of a PbI2 solution layer at 2500 rpm for 30 seconds. The layer is then annealed for 15 minutes on a hot plate at 150°C outside a glove box, ensuring the air humidity is controlled to 20-40% relative humidity (RH). This yields a perovskite film, which comprises an organic ammonium salt embedded interface layer, a perovskite layer, and a polyelectrolyte interface layer sequentially stacked on the substrate surface.

[0123] PCBM was dissolved in chlorobenzene to obtain an electron transport layer precursor solution with a mass concentration of 20 mg / mL. The electron transport layer precursor solution was spin-coated onto the surface of the perovskite layer at a spin speed of 1000 rpm for 30 s to obtain the electron transport layer. Alternatively, a C60 electron transport layer with a thickness of 25-50 nm could also be deposited via vacuum deposition at a deposition rate of [missing information]. No thermal annealing is required after deposition.

[0124] Subsequently, a BCP interface buffer layer is prepared, which can be prepared by solution method or vacuum evaporation. For the solution method, BCP is first dissolved in ethanol to obtain an interface buffer layer precursor solution with a mass concentration of 1 mg / mL. This precursor solution is then spin-coated onto the electron transport layer surface at a speed of 5000 rpm for 30 s to obtain the BCP interface buffer layer. For the vacuum evaporation method, the chamber pressure is 4 × 10⁻⁶. -4 The PA thickness is 5-10 nm, and the evaporation rate is... No thermal annealing is required after deposition.

[0125] Finally, a copper electrode with a thickness of 100 nm was vacuum-deposited on the surface of the BCP interface buffer layer to obtain a perovskite solar cell.

[0126] Example 2

[0127] The ITO transparent conductive substrate was cleaned by ultrasonic cleaning for 15 minutes each using glass cleaner, deionized water, acetone, and isopropanol.

[0128] The cleaned ITO transparent conductive substrate was treated with UV-O3 for 15 minutes to remove residual organic matter on the surface of the transparent ITO conductive substrate and improve its work function.

[0129] PTAA was dissolved in toluene to obtain a hole transport layer precursor solution with a mass concentration of 2 mg / mL. The hole transport layer precursor solution was spin-coated onto the surface of an ITO conductive substrate at a spin speed of 5000 rpm for 30 s to obtain a hole transport layer precursor solution layer. Subsequently, it was annealed at 120 °C for 10 min to obtain the hole transport layer.

[0130] PFN-Br and hexyltrimethylammonium bromide (HTAB) were dissolved in methanol at a mass ratio of 1:10 to obtain an interface treatment solution with a total mass concentration of 11 mg / mL. The interface treatment solution was heated and stirred on a hot plate at 50 °C, and then spin-coated onto the surface of the hole transport layer at a spin speed of 5000 rpm for 30 s to obtain an interface treatment solution layer. Subsequently, the solution was annealed at 100 °C for 5 min to obtain the interface layer.

[0131] PbI2 was dissolved in DMF and DMSO to obtain a PbI2 solution. The preferred mass concentration of the PbI2 solution was 691.5 mg / mL. The solvent was a mixture of DMF and DMSO (volume ratio DMF:DMSO = 9:1). The PbI2 solution was spin-coated onto the surface of the interface layer at a speed of 1500 rpm for 30 s. Then, it was annealed on a hot plate at 70°C for 1 min to obtain a PbI2 coating.

[0132] FAI, MAI, and MACl are co-dissolved to obtain a mixed solution. The solvent in this solution is preferably isopropanol. The preferred mass concentrations of FAI, MAI, and MACl in the mixed solution are 90 mg / mL, 6.39 mg / mL, and 9 mg / mL. The FAI, MAI, and MACl solution is then spin-coated onto the surface of a PbI2 solution layer at 2500 rpm for 30 seconds. The layer is then annealed for 15 minutes on a hot plate at 150°C outside a glove box, ensuring the air humidity is controlled to 20-40% relative humidity (RH). This yields a perovskite film, which comprises an organic ammonium salt embedded interface layer, a perovskite layer, and a polyelectrolyte interface layer sequentially stacked on the substrate surface.

[0133] PCBM was dissolved in chlorobenzene to obtain an electron transport layer precursor solution with a mass concentration of 20 mg / mL. The electron transport layer precursor solution was spin-coated onto the surface of the perovskite layer at a spin speed of 1000 rpm for 30 s to obtain the electron transport layer. Alternatively, a C60 electron transport layer with a thickness of 25-50 nm could also be deposited via vacuum deposition at a deposition rate of [missing information]. No thermal annealing is required after deposition.

[0134] Subsequently, a BCP interface buffer layer is prepared, which can be prepared by solution method or vacuum evaporation. For the solution method, BCP is first dissolved in ethanol to obtain an interface buffer layer precursor solution with a mass concentration of 1 mg / mL. This precursor solution is then spin-coated onto the electron transport layer surface at a speed of 5000 rpm for 30 s to obtain the BCP interface buffer layer. For the vacuum evaporation method, the chamber pressure is 4 × 10⁻⁶. -4 The PA thickness is 5-10 nm, and the evaporation rate is... No thermal annealing is required after deposition.

[0135] Finally, a copper electrode with a thickness of 100 nm was vacuum-deposited on the surface of the BCP interface buffer layer to obtain a perovskite solar cell.

[0136] Example 3

[0137] The ITO transparent conductive substrate was cleaned by ultrasonic cleaning for 15 minutes each using glass cleaner, deionized water, acetone, and isopropanol.

[0138] The cleaned ITO transparent conductive substrate was treated with UV-O3 for 15 minutes to remove residual organic matter on the surface of the transparent ITO conductive substrate and improve its work function.

[0139] PTAA was dissolved in toluene to obtain a hole transport layer precursor solution with a mass concentration of 2 mg / mL. The hole transport layer precursor solution was spin-coated onto the surface of an ITO conductive substrate at a spin speed of 5000 rpm for 30 s to obtain a hole transport layer precursor solution layer. Subsequently, it was annealed at 120 °C for 10 min to obtain the hole transport layer.

[0140] PFN-Br was dissolved in methanol to obtain a first interface treatment solution with a PFN-Br concentration of 1 mg / mL. The first interface treatment solution was heated and stirred on a hot plate at 50°C. The first interface treatment solution was then spin-coated onto the surface of the hole transport layer at a spin speed of 5000 rpm for 30 s to obtain the first interface treatment solution layer.

[0141] Phenylacetium iodide (PEAI) was dissolved in methanol to obtain a second interface treatment solution with a PEAI concentration of 10 mg / mL. The second interface treatment solution was then spin-coated onto the surface of the first interface treatment solution layer at a spin speed of 5000 rpm for 30 s to obtain the second interface treatment solution layer. Subsequently, the solution was annealed at 100 °C for 5 min to obtain the interface layer.

[0142] PbI2 was dissolved in DMF and DMSO to obtain a PbI2 solution. The preferred mass concentration of the PbI2 solution was 691.5 mg / mL, and the solvent was a mixture of DMF and DMSO (DMF:DMSO = 9:1). The PbI2 solution was spin-coated onto the surface of the interface layer at a speed of 1500 rpm for 30 s, and then annealed on a hot plate at 70°C for 1 min to obtain a PbI2 coating.

[0143] FAI, MAI, and MACl are co-dissolved to obtain a mixed solution. The solvent in this solution is preferably isopropanol (IPA). The preferred mass concentrations of FAI, MAI, and MACl in the mixed solution are 90 mg / mL, 6.39 mg / mL, and 9 mg / mL. The FAI, MAI, and MACl solution is then spin-coated onto the surface of a PbI2 solution layer at 2500 rpm for 30 seconds. The layer is then annealed for 15 minutes on a hot plate at 150°C outside a glove box, ensuring the air humidity is controlled to 20-40% relative humidity (RH). This yields a perovskite film, which comprises an organic ammonium salt embedded interface layer, a perovskite layer, and a polyelectrolyte interface layer sequentially stacked on the substrate surface.

[0144] PCBM was dissolved in chlorobenzene to obtain an electron transport layer precursor solution with a mass concentration of 20 mg / mL. The electron transport layer precursor solution was spin-coated onto the surface of the perovskite layer at a spin speed of 1000 rpm for 30 s to obtain the electron transport layer. Alternatively, a C60 electron transport layer with a thickness of 25-50 nm could also be deposited via vacuum deposition at a deposition rate of [missing information]. No thermal annealing is required after deposition.

[0145] Subsequently, a BCP interface buffer layer is prepared, which can be prepared by solution method or vacuum evaporation. For the solution method, BCP is first dissolved in ethanol to obtain an interface buffer layer precursor solution with a mass concentration of 1 mg / mL. This precursor solution is then spin-coated onto the electron transport layer surface at a speed of 5000 rpm for 30 s to obtain the BCP interface buffer layer. For the vacuum evaporation method, the chamber pressure is 4 × 10⁻⁶. -4 The PA thickness is 5-10 nm, and the evaporation rate is... No thermal annealing is required after deposition.

[0146] Finally, a copper electrode with a thickness of 100 nm was vacuum-deposited on the surface of the BCP interface buffer layer to obtain a perovskite solar cell.

[0147] Example 4

[0148] The ITO transparent conductive substrate was cleaned by ultrasonic cleaning for 15 minutes each using glass cleaner, deionized water, acetone, and isopropanol.

[0149] The cleaned ITO transparent conductive substrate was treated with UV-O3 for 15 minutes to remove residual organic matter on the surface of the transparent ITO conductive substrate and improve its work function.

[0150] A self-assembled monolayer of [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACz) was dissolved in isopropanol to obtain a hole transport layer precursor solution with a mass concentration of 0.5 mg / mL. The hole transport layer precursor solution was spin-coated onto the surface of an ITO conductive substrate at a spin speed of 3000 rpm for 30 s to obtain a hole transport layer precursor solution layer. Subsequently, it was annealed at 100 °C for 10 min to obtain the hole transport layer.

[0151] PFN-Br and phenylethylammonium iodide (PEAI) were dissolved in methanol at a mass ratio of 1:10 to obtain an interface treatment solution with a total mass concentration of 11 mg / mL. The interface treatment solution was heated and stirred on a hot plate at 50 °C, and then dynamically spin-coated onto the surface of the hole transport layer at a spin speed of 5000 rpm for 30 s to obtain an interface treatment solution layer. Subsequently, the solution was annealed at 100 °C for 5 min to obtain the interface layer.

[0152] A mixed solution of CsI, RbI, MABr, FAI, PbI2 and PbBr2 is coated onto the surface of the interface layer to obtain a mixed solution layer of CsI, RbI, MABr, FAI, PbI2 and PbBr2. The mixed solution layer of CsI, RbI, MABr, FAI, PbI2 and PbBr2 is then annealed to obtain the perovskite layer.

[0153] In this invention, the solvent in the mixed solution of CsI, RbI, MABr, FAI, PbI2, and PbBr2 is preferably a blend of DMF and DMSO (volume ratio DMF:DMSO = 4:1). The preferred mass concentrations of CsI, RbI, MABr, FAI, PbI2, and PbBr2 in the mixed solution are 19.5 mg / mL for CsI, 15.9 mg / mL for RbI, 8.4 mg / mL for MABr, 19.5 mg / mL for FAI2, 656.9 mg / mL for PbI2, and 27.5 mg / mL for PbBr2. The coating is preferably spin-coating, with the preferred spin-coating speeds being 1000 rpm for 10 seconds in the first step, 3000 rpm for 30 seconds in the second step, and 150 μL of the anti-solvent chlorobenzene added dropwise at the 15th second of the second step. The preferred annealing temperature is 100°C, and the preferred annealing time is 10 minutes.

[0154] PCBM was dissolved in chlorobenzene to obtain an electron transport layer precursor solution with a mass concentration of 20 mg / mL. The electron transport layer precursor solution was spin-coated onto the surface of the perovskite layer at a spin speed of 1000 rpm for 30 s to obtain the electron transport layer. Alternatively, a C60 electron transport layer with a thickness of 25-50 nm could also be deposited via vacuum deposition at a deposition rate of [missing information]. No thermal annealing is required after deposition.

[0155] Subsequently, a BCP interface buffer layer is prepared, which can be prepared by solution method or vacuum evaporation. For the solution method, BCP is first dissolved in ethanol to obtain an interface buffer layer precursor solution with a mass concentration of 1 mg / mL. This precursor solution is then spin-coated onto the electron transport layer surface at a speed of 5000 rpm for 30 s to obtain the BCP interface buffer layer. For the vacuum evaporation method, the chamber pressure is 4 × 10⁻⁶. -4 The PA thickness is 5-10 nm, and the evaporation rate is... No thermal annealing is required after deposition.

[0156] Finally, a copper electrode with a thickness of 100 nm was vacuum-deposited on the surface of the BCP interface buffer layer to obtain a perovskite solar cell.

[0157] Comparative Example 1

[0158] The ITO transparent conductive substrate was cleaned by ultrasonic cleaning for 15 minutes each using glass cleaner, deionized water, acetone, and isopropanol.

[0159] The cleaned ITO transparent conductive substrate was treated with UV-O3 for 15 minutes to remove residual organic matter on the surface of the transparent ITO conductive substrate and improve its work function.

[0160] PTAA was dissolved in toluene to obtain a hole transport layer precursor solution with a mass concentration of 2 mg / mL. The hole transport layer precursor solution was spin-coated onto the surface of an ITO conductive substrate at a spin speed of 5000 rpm for 30 s to obtain a hole transport layer precursor solution layer. Subsequently, it was annealed at 120 °C for 10 min to obtain the hole transport layer.

[0161] PFN-Br was dissolved in methanol to obtain an interface treatment solution with a PFN-Br concentration of 1 mg / mL. The interface treatment solution was heated and stirred on a hot plate at 50 °C, and then spin-coated onto the surface of the hole transport layer at a spin speed of 5000 rpm for 30 s to obtain an interface treatment solution layer. Subsequently, it was annealed at 100 °C for 5 min to obtain the interface layer.

[0162] PbI2 was dissolved in DMF and DMSO to obtain a PbI2 solution. The preferred mass concentration of the PbI2 solution was 691.5 mg / mL. The solvent was a mixture of DMF and DMSO (volume ratio DMF:DMSO = 9:1). The PbI2 solution was spin-coated onto the surface of the interface layer at a speed of 1500 rpm for 30 s. Then, it was annealed on a hot plate at 70°C for 1 min to obtain a PbI2 coating.

[0163] FAI, MAI, and MACl are co-dissolved to obtain a mixed solution. The solvent in this solution is preferably isopropanol (IPA). The preferred mass concentrations of FAI, MAI, and MACl in the mixed solution are 90 mg / mL, 6.39 mg / mL, and 9 mg / mL. The FAI, MAI, and MACl solution is then spin-coated onto the surface of a PbI2 solution layer at 2500 rpm for 30 seconds. The layer is then annealed for 15 minutes on a hot plate at 150°C outside a glove box, ensuring the air humidity is controlled to 20-40% relative humidity (RH). This yields a perovskite film, which comprises an organic ammonium salt embedded interface layer, a perovskite layer, and a polyelectrolyte interface layer sequentially stacked on the substrate surface.

[0164] PCBM was dissolved in chlorobenzene to obtain an electron transport layer precursor solution with a mass concentration of 20 mg / mL. The electron transport layer precursor solution was spin-coated onto the surface of the perovskite layer at a spin speed of 1000 rpm for 30 s to obtain the electron transport layer. Alternatively, a C60 electron transport layer with a thickness of 25-50 nm could also be deposited via vacuum deposition at a deposition rate of [missing information]. No thermal annealing is required after deposition.

[0165] Subsequently, a BCP interface buffer layer is prepared, which can be prepared by solution method or vacuum evaporation. For the solution method, BCP is first dissolved in ethanol to obtain an interface buffer layer precursor solution with a mass concentration of 1 mg / mL. This precursor solution is then spin-coated onto the electron transport layer surface at a speed of 5000 rpm for 30 s to obtain the BCP interface buffer layer. For the vacuum evaporation method, the chamber pressure is 4 × 10⁻⁶. -4 The PA thickness is 5-10 nm, and the evaporation rate is... No thermal annealing is required after deposition.

[0166] Finally, a copper electrode with a thickness of 100 nm was vacuum-deposited on the surface of the BCP interface buffer layer to obtain a perovskite solar cell.

[0167] Comparative Example 2

[0168] The ITO transparent conductive substrate was cleaned by ultrasonic cleaning for 15 minutes each using glass cleaner, deionized water, acetone, and isopropanol.

[0169] The cleaned ITO transparent conductive substrate was treated with UV-O3 for 15 minutes to remove residual organic matter on the surface of the transparent ITO conductive substrate and improve its work function.

[0170] PTAA was dissolved in toluene to obtain a hole transport layer precursor solution with a mass concentration of 2 mg / mL. The hole transport layer precursor solution was spin-coated onto the surface of an ITO conductive substrate at a spin speed of 5000 rpm for 30 s to obtain a hole transport layer precursor solution layer. Subsequently, it was annealed at 120 °C for 10 min to obtain the hole transport layer.

[0171] PEAI was dissolved in methanol to obtain an interface treatment solution with a PEAI concentration of 10 mg / mL. The solution was rapidly dissolved by shaking at room temperature. The interface treatment solution was then spin-coated onto the surface of the hole transport layer at a spin speed of 5000 rpm for 30 s to obtain an interface treatment solution layer. Subsequently, the solution was annealed at 100 °C for 5 min to obtain the interface layer.

[0172] PbI2 was dissolved in DMF and DMSO to obtain a PbI2 solution. The preferred mass concentration of the PbI2 solution was 691.5 mg / mL. The solvent was a mixture of DMF and DMSO (volume ratio DMF:DMSO = 9:1). The PbI2 solution was spin-coated onto the surface of the interface layer at a speed of 1500 rpm for 30 s. Then, it was annealed on a hot plate at 70°C for 1 min to obtain a PbI2 coating.

[0173] FAI, MAI, and MACl are co-dissolved to obtain a mixed solution. The solvent in this solution is preferably isopropanol (IPA). The preferred mass concentrations of FAI, MAI, and MACl in the mixed solution are 90 mg / mL, 6.39 mg / mL, and 9 mg / mL. The FAI, MAI, and MACl solution is then spin-coated onto the surface of a PbI2 solution layer at 2500 rpm for 30 seconds. The layer is then annealed for 15 minutes on a hot plate at 150°C outside a glove box, ensuring the air humidity is controlled to 20-40% relative humidity (RH). This yields a perovskite film, which comprises an organic ammonium salt embedded interface layer, a perovskite layer, and a polyelectrolyte interface layer sequentially stacked on the substrate surface.

[0174] PCBM was dissolved in chlorobenzene to obtain an electron transport layer precursor solution with a mass concentration of 20 mg / mL. The electron transport layer precursor solution was spin-coated onto the surface of the perovskite layer at a spin speed of 1000 rpm for 30 s to obtain the electron transport layer. Alternatively, a C60 electron transport layer with a thickness of 25-50 nm could also be deposited via vacuum deposition at a deposition rate of [missing information]. No thermal annealing is required after deposition.

[0175] Subsequently, a BCP interface buffer layer is prepared, which can be prepared by solution method or vacuum evaporation. For the solution method, BCP is first dissolved in ethanol to obtain an interface buffer layer precursor solution with a mass concentration of 1 mg / mL. This precursor solution is then spin-coated onto the electron transport layer surface at a speed of 5000 rpm for 30 seconds, resulting in the copper bath interface buffer layer. For the vacuum evaporation method, the chamber pressure is 4 × 10⁻⁶. -4 The PA thickness is 5-10 nm, and the evaporation rate is... No thermal annealing is required after deposition.

[0176] Finally, a copper electrode with a thickness of 100 nm was vacuum-deposited on the surface of the copper bath interface buffer layer to obtain a perovskite solar cell.

[0177] Comparative Example 3

[0178] The ITO transparent conductive substrate was cleaned by ultrasonic cleaning for 15 minutes each using glass cleaner, deionized water, acetone, and isopropanol.

[0179] The cleaned ITO transparent conductive substrate was treated with UV-O3 for 15 minutes to remove residual organic matter on the surface of the transparent ITO conductive substrate and improve its work function.

[0180] A self-assembled monolayer of [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACz) was dissolved in isopropanol to obtain a hole transport layer precursor solution with a mass concentration of 0.5 mg / mL. The hole transport layer precursor solution was spin-coated onto the surface of an ITO conductive substrate at a spin speed of 3000 rpm for 30 s to obtain a hole transport layer precursor solution layer. Subsequently, it was annealed at 100 °C for 10 min to obtain the hole transport layer.

[0181] A mixed solution of CsI, RbI, MABr, FAI, PbI2, and PbBr2 is coated onto the surface of the interface layer to obtain a mixed solution layer of CsI, RbI, MABr, FAI, PbI2, and PbBr2. The mixed solution layer of CsI, RbI, MABr, FAI, PbI2, and PbBr2 is then annealed to obtain the perovskite layer.

[0182] In this invention, the solvent in the mixed solution of CsI, RbI, MABr, FAI, PbI2, and PbBr2 is preferably a blend of DMF and DMSO (volume ratio DMF:DMSO = 4:1). The preferred mass concentrations of CsI, RbI, MABr, FAI, PbI2, and PbBr2 in the mixed solution are 19.5 mg / mL, 15.9 mg / mL, 8.4 mg / mL, 219.5 mg / mL, 656.9 mg / mL, and 27.5 mg / mL. The coating is preferably spin-coating, with the preferred spin-coating speeds being 1000 rpm for 10 s in the first step, 3000 rpm for 30 s in the second step, and 150 μL of the anti-solvent chlorobenzene added dropwise at the 15th second of the second step. The preferred annealing temperature is 100°C, and the preferred annealing time is 10 min.

[0183] PCBM was dissolved in chlorobenzene to obtain an electron transport layer precursor solution with a mass concentration of 20 mg / mL. The electron transport layer precursor solution was spin-coated onto the surface of the perovskite layer at a spin speed of 1000 rpm for 30 s to obtain the electron transport layer. Alternatively, a C60 electron transport layer with a thickness of 25-50 nm could also be deposited via vacuum deposition at a deposition rate of [missing information]. No thermal annealing is required after deposition.

[0184] Subsequently, a BCP interface buffer layer is prepared, which can be prepared by solution method or vacuum evaporation. For the solution method, BCP is first dissolved in ethanol to obtain an interface buffer layer precursor solution with a mass concentration of 1 mg / mL. This precursor solution is then spin-coated onto the electron transport layer surface at 5000 rpm for 30 seconds to obtain the BCP interface buffer layer. For the vacuum evaporation method, the chamber pressure is 4*10... -4 The PA thickness is 5-10 nm, and the evaporation rate is... No thermal annealing is required after deposition.

[0185] Finally, a copper electrode with a thickness of 100 nm was vacuum-deposited on the surface of the BCP interface buffer layer to obtain a perovskite solar cell.

[0186] Test Example 1

[0187] Figure 1 Scanning electron microscope images of the perovskite thin film prepared in Example 1, Comparative Example 1, and Comparative Example 2 of the present invention. Figure 1 The left image in the figure is a scanning electron microscope image of the perovskite thin film prepared in Comparative Example 1. Figure 1 The middle image in the figure is a scanning electron microscope image of the perovskite thin film prepared in Comparative Example 2. Figure 1 The right-hand image in the figure is a scanning electron microscope image of the perovskite thin film prepared in Example 1. Figure 2 This is a secondary primitive characterization diagram of the time-of-flight of the perovskite thin film prepared in Example 1 of the present invention.

[0188] Depend on Figure 1 and Figure 2 It can be concluded that in perovskite films, polyelectrolytes spontaneously accumulate on the surface of the perovskite layer, and the energy groups contained in PFN-Br can passivate surface defects of the perovskite layer. At the same time, PFN-Br contains hydrophobic aliphatic chains, which can act as a protective layer to improve device stability. Organic amine salt PEAI spontaneously accumulates at the buried interface of the perovskite layer, passivating the buried interface defects. At the same time, it forms a band arrangement structure that is more conducive to carrier transport at the buried interface, reducing carrier recombination at the interface.

[0189] Test Example 2

[0190] Figure 3 The transient and time-resolved fluorescence spectra of the perovskite films prepared in Example 1, Comparative Example 1, and Comparative Example 2 are characterization images. Figure 3It can be concluded that the perovskite film prepared in Example 1 of the present invention has significantly improved transient fluorescence and time-resolved fluorescence spectral characteristics compared with the perovskite films prepared in Comparative Examples 1 and 2. This indicates that the perovskite film prepared in Example 1 (Example 1) has the least defect content and non-radiative recombination is also significantly suppressed.

[0191] Test Example 3

[0192] Figure 4 The figures show the performance characteristics of the perovskite solar cells prepared in Example 1, Comparative Example 1, and Comparative Example 2 of this invention. Figure 4 The performance test conditions for product aging shown in the right figure are: heating at 85℃, nitrogen environment, indoor light irradiation, and aging time of 500 hours.

[0193] Depend on Figure 4 As shown in the right figure, co-processing of PFN-Br and PEAI achieved a photoelectric conversion efficiency of over 23%, while the stability of the device was also significantly improved.

[0194] Test Example 4

[0195] Figure 5 This is a performance comparison chart of the perovskite solar cell (denoted as the Target device) prepared in Example 4 of the present invention and the perovskite solar cell (denoted as the Control device) prepared in Comparative Example 3; [The chart is missing from the original text.] Figure 5 It can be concluded that the preparation method provided by the present invention has good universality, and is not only applicable to the two-step method for preparing perovskite thin films in Example 1, but also compatible with the one-step method for preparing perovskite thin films.

[0196] Figure 6 This is a performance comparison chart between the perovskite thin-film solar cell prepared in Example 2 of the present invention and the perovskite solar cell prepared in Comparative Example 1. (From...) Figure 6 It can be concluded that the method provided by the present invention is not limited to the use of PEAI ammonium salt. The co-processing of HTAB and PFN-Br can also improve the photoelectric conversion performance of perovskite solar cells.

[0197] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing a perovskite thin film, characterized in that, Includes the following steps: An interface treatment solution is coated on the surface of the hole transport layer to obtain an interface treatment coating; the hole transport layer is made of poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], and the interface treatment solution includes a polyelectrolyte, an organic ammonium salt and an organic solvent; the polyelectrolyte is poly(9,9-bis(3'-(N,N-dimethyl)-N-ethylaminopropyl-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)) dibromide, and the organic ammonium salt is phenethylamine iodide or ethyltrimethylammonium bromide; the mass ratio of the polyelectrolyte to the organic ammonium salt is 1:

10. The interface treatment coating is annealed to obtain the interface layer; A perovskite layer is prepared by coating the surface of the interface layer with a perovskite precursor solution to obtain the perovskite film. The solvent in the perovskite precursor solution is a solvent capable of dissolving the polyelectrolyte and the organic ammonium salt. A perovskite film is obtained on the surface of the hole transport layer, the perovskite film comprising an organic ammonium salt buried interface layer, a perovskite layer and a polyelectrolyte interface surface layer stacked sequentially.

2. The preparation method according to claim 1, characterized in that, The annealing temperature is room temperature to 150°C, and the annealing holding time is 5 to 10 minutes.

3. The perovskite thin film prepared by the preparation method according to claim 1 or 2, characterized in that, The perovskite film comprises an organic ammonium salt buried interface layer, a perovskite layer, and a polyelectrolyte interface layer stacked sequentially.

4. The perovskite thin film according to claim 3, characterized in that, The thicknesses of the organic ammonium salt buried interface layer and the polyelectrolyte interface surface layer are independently 0.5~30 nm.

5. A perovskite solar cell, comprising a conductive substrate and a hole transport layer, a perovskite thin film, an electron transport layer, an interface buffer layer, and an electrode sequentially stacked on the surface of the conductive substrate, characterized in that, The perovskite film is the perovskite film according to claim 3 or 4.

6. The method for preparing the perovskite solar cell according to claim 5, characterized in that, Includes the following steps: A hole transport layer is prepared on the surface of the conductive substrate; A perovskite thin film is prepared on the surface of the hole transport layer according to the method of claim 1 or 2; An electron transport layer is prepared on the surface of the perovskite thin film; An interface buffer layer is prepared on the surface of the electron transport layer; An electrode is fabricated on the surface of the interface buffer layer to obtain the perovskite solar cell.

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