A porous supramolecular assembly modified perovskite thin film, a preparation method and a photovoltaic cell

Abstract

The application belongs to the technical field of photovoltaic cell materials, and particularly relates to a porous supramolecular assembly modified perovskite film, a preparation method thereof and a photovoltaic cell. The application provides a preparation method of a porous supramolecular assembly modified perovskite film. In the perovskite precursor solution, 4-sulfonate calix[4]arene supramolecules are introduced, a wet film is formed after spin coating, and in-situ host-guest self-assembly occurs with an anti-solvent containing 1-amine ethyl-3-methyl imidazole bromide in the post-processing annealing stage, so that the porous supramolecular assembly is in-situ crosslinked and uniformly distributed at perovskite grain boundaries. The formed supramolecular assembly has a cyclic sequence cavity structure, can be used as a perovskite crystallization template to effectively improve perovskite crystallization nucleation, improve perovskite film crystallization, and thus improve the perovskite film quality, and solve the technical problems of perovskite film efficiency bottleneck and low stability.

Description

Technical Field

[0001] This application belongs to the field of photovoltaic cell material technology, and in particular relates to a porous supramolecular assembly modified perovskite thin film, its preparation method, and a photovoltaic cell. Background Technology

[0002] Perovskite photovoltaic cells are a type of photovoltaic cell that uses a perovskite thin film as the core functional layer, and combines it with a conductive glass substrate, an electron transport layer, a hole transport layer, and a metal top electrode to achieve the process of "light absorption → carrier separation → charge transport → electrical energy output", thus converting it into electrical energy using the photovoltaic effect.

[0003] To improve the stability of perovskite thin films under high temperature and high humidity environments, reduce internal defects, and enhance photoelectric conversion efficiency, it is necessary to modify and alter perovskite thin films to improve the photoelectric conversion efficiency and stability of photovoltaic cells. Therefore, it is essential to develop novel perovskite thin film modification and alteration technologies to improve the performance of perovskite thin films. Summary of the Invention

[0004] In view of this, this application provides a porous supramolecular assembly-modified perovskite thin film, its preparation method, and a photovoltaic cell, which are used to solve the technical problems of low efficiency and low stability of perovskite thin films.

[0005] The first aspect of this application provides a method for preparing a porous supramolecular assembly-modified perovskite thin film, the method comprising the following steps:

[0006] Steps for preparing perovskite thin film raw materials: Weigh the corresponding lead halide, formamidinium halide, methylammonium halide and cesium halide according to the ABX3 perovskite structure;

[0007] The steps for preparing a supramolecular doped modified perovskite precursor solution are as follows: Weigh lead halide, formamidinium halide, methyl ammonium halide and cesium halide and 4-sulfonyl calix[4] aromatic supramolecular dissolve in a mixed organic solvent to obtain a supramolecular doped modified perovskite precursor solution.

[0008] The steps for preparing the assembly monomer solution are as follows: Dissolve 1-aminoethyl-3-methylimidazolium bromide in the antisolvent corresponding to the mixed organic solvent to obtain the assembly monomer solution;

[0009] The steps for spin-coating to prepare a perovskite wet film are as follows: a supramolecular-doped modified perovskite precursor solution is spin-coated onto a substrate to obtain a supramolecular-doped modified perovskite wet film.

[0010] The steps for preparing in-situ crosslinked supramolecular assembly modified perovskite films are as follows: spin-coating the assembly monomer solution onto the surface of the supramolecular doped modified perovskite wet film, followed by annealing to obtain porous supramolecular assembly modified perovskite films.

[0011] Preferably, the mass ratio of 4-sulfonylcalix[4] aromatic supramolecular in the supramolecular doped perovskite precursor solution to 1-aminoethyl-3-methylimidazolium bromide in the assembly monomer solution is 1:1~5.

[0012] Preferably, the annealing temperature is 80℃~120℃ and the time is 20min~40min.

[0013] Preferably, in the supramolecular doped modified perovskite precursor solution, the lead halide solute is selected from at least one of lead iodide, lead bromide, and lead chloride;

[0014] The solute formamidine halide is selected from at least one of formamidine iodide, formamidine bromide, and formamidine chloride;

[0015] The solute, methyl ammonium halide, is selected from at least one of methyl ammonium iodide, methyl ammonium bromide, and methyl ammonium chloride.

[0016] The solute cesium halide is selected from at least one of cesium iodide, cesium bromide, and cesium chloride.

[0017] Preferably, in the supramolecular doped modified perovskite precursor solution, the concentration of lead iodide solute is 800 mg / mL, the concentration of formamidinium iodide solute is 237 mg / mL, the concentration of methylammonium iodide solute is 26 mg / mL, the concentration of methylammonium chloride solute is 10 mg / mL, and the concentration of cesium iodide solute is 23 mg / mL.

[0018] Preferably, the concentration of the solute 4-sulfonylcalix[4]arene supramolecular in the supramolecular doped and modified perovskite precursor solution is 0.5 mg / mL to 2.5 mg / mL.

[0019] Preferably, the concentration of 1-aminoethyl-3-methylimidazolium bromide in the assembly monomer solution is 0.5 mg / mL to 2.5 mg / mL.

[0020] Preferably, the mixed organic solvent is a mixture of formamide and dimethyl sulfoxide in a volume ratio of 4:1, and the antisolvent is chlorobenzene.

[0021] The second aspect of this application provides a porous supramolecular assembly modified perovskite thin film, which is prepared by the preparation method described in the first aspect.

[0022] The third aspect of this application provides a perovskite photovoltaic cell, including a perovskite thin film modified with a porous supramolecular assembly as described in the second aspect. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 A schematic flowchart illustrating a method for preparing a porous supramolecular assembly-modified perovskite thin film provided in Example 1 of this application;

[0025] Figure 2 A schematic diagram of the reaction between the 4-sulfonylcalix[4] aromatic supramolecular provided in Experimental Example 1 of this application and 1-aminoethyl-3-methylimidazolium bromide to form a porous supramolecular assembly;

[0026] Figure 3 Field emission scanning electron microscope images of the 4-sulfonyl calix [4] aromatic supramolecular and the porous supramolecular assembly provided in Experimental Example 1 of this application;

[0027] Figure 4 Infrared spectra of the 4-sulfonyl calix [4] aromatic supramolecular, 1-aminoethyl-3-methylimidazolium bromide and porous supramolecular assembly provided in Experimental Example 1 of this application;

[0028] Figure 5 The 1H NMR spectra of the 4-sulfonylcalix[4] aromatic supramolecular, 1-aminoethyl-3-methylimidazolium bromide and porous supramolecular assembly provided in Experimental Example 1 of this application;

[0029] Figure 6 Field emission scanning electron microscope images of the perovskite film modified by the porous supramolecular assembly provided in Example 1 of this application, the perovskite film modified by the 4-sulfonyl calix [4] aromatic hydrocarbon supramolecular assembly provided in Example 2, and the perovskite film provided in Comparative Example 1;

[0030] Figure 7 X-ray diffraction patterns of the perovskite film modified by the porous supramolecular assembly provided in Example 1 of this application, the perovskite film modified by the 4-sulfonyl cup[4]arene supramolecular assembly provided in Example 2, and the perovskite film provided in Comparative Example 1;

[0031] Figure 8 Atomic force microscopy images of the perovskite film modified with the porous supramolecular assembly provided in Example 1 of this application and the perovskite film provided in Comparative Example 1.

[0032] Figure 9Phase angle images of the perovskite thin film modified with the porous supramolecular assembly provided in Example 1 of this application and the perovskite thin film provided in Comparative Example 1, with corresponding atomic force microscopy morphology insets.

[0033] Figure 10 In-situ UV-Vis absorption spectra of the perovskite film modified with the porous supramolecular assembly provided in Example 1 of this application and the perovskite film provided in Comparative Example 1 during annealing.

[0034] Figure 11 Field emission scanning electron microscope (FESEM) images of the perovskite thin film modified with the porous supramolecular assembly provided in Example 1 of this application and the perovskite thin film provided in Comparative Example 1 after 0 hours, 300 hours, and 600 hours in an atmospheric environment with 50±3% humidity.

[0035] Figure 12 X-ray diffraction patterns of the perovskite film modified with the porous supramolecular assembly provided in Example 1 of this application and the perovskite film provided in Comparative Example 1 after 600 hours in an atmospheric environment with 50±3% humidity.

[0036] Figure 13 The photoelectric conversion efficiency test results of the perovskite photovoltaic cells assembled from the porous supramolecular assembly modified by Example 1 of this application, the 4-sulfonyl calix [4] aromatic supramolecular modified perovskite film provided by Example 2, and the perovskite film provided by Comparative Example 1;

[0037] Figure 14 The external quantum efficiency test results of perovskite photovoltaic cells assembled from the porous supramolecular assembly modified by Example 1 of this application, the 4-sulfonyl cup [4] aromatic supramolecular modified perovskite film provided by Example 2, and the perovskite film provided by Comparative Example 1;

[0038] In the attached figure, monomer 1 is a 4-sulfonylcalix[4] aromatic supramolecular, monomer 2 is 1-aminoethyl-3-methylimidazolium bromide, and the assembly is a porous supramolecular assembly;

[0039] Appendix Figure 3 In the figure, (a) is a field emission scanning electron microscope image of a sample made from 4-sulfonylcalix[4] aromatic supramoleculars, (b) is a field emission scanning electron microscope image of a sample made from a porous supramolecular assembly obtained by reacting 4-sulfonylcalix[4] aromatic supramoleculars and 1-aminoethyl-3-methylimidazolium bromide in a mass ratio of 1:1, and (c) is a field emission scanning electron microscope image of a sample made from a porous supramolecular assembly obtained by reacting 4-sulfonylcalix[4] aromatic supramoleculars and 1-aminoethyl-3-methylimidazolium bromide in a mass ratio of 1:2.

[0040] Appendix Figure 5In the figure, (a) is the full spectrum of the 1H NMR spectrum, and (b) is a partial spectrum of the 1H NMR spectrum. Detailed Implementation

[0041] This application provides a porous supramolecular assembly-modified perovskite thin film, its preparation method, and a photovoltaic cell, which are used to solve the technical problems of efficiency bottleneck and low stability of perovskite thin films.

[0042] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0043] Perovskite films prepared by traditional spin coating methods have a high density of internal defect states before modification, making it difficult to maintain their original structure under high temperature and high humidity environments. To improve the stability of perovskite films under high temperature and high humidity environments, reduce internal defects, and improve photoelectric conversion efficiency, it is necessary to modify the perovskite films to improve the photoelectric conversion efficiency and stability of photovoltaic cells. However, there are currently not enough technical means to modify perovskite films, so it is necessary to develop novel perovskite film modification techniques to improve the performance of perovskite films. In view of this, this application provides a method for preparing perovskite films modified with porous supramolecular assemblies.

[0044] This application provides a method for preparing a porous supramolecular assembly-modified perovskite film, which is prepared by spin coating. The preparation method first introduces 4-sulfonylcalix[4] aromatic supramoleculars into perovskite precursor solutions such as lead halide, formamidinium halide, methylammonium halide and cesium halide, and simultaneously dissolves 1-aminoethyl-3-methylimidazolium bromide in an antisolvent to prepare an assembly monomer solution. Then, the perovskite precursor solution with introduced 4-sulfonylcalix[4] aromatic supramoleculars is spin-coated onto the surface of a substrate such as conductive glass to form a wet film. Next, the assembly monomer solution is spin-coated onto the surface of the wet film and annealed to obtain a porous supramolecular assembly-modified perovskite film. During the preparation of the perovskite film, due to the hydrogen bond, electrostatic and other interactions between 4-sulfonylcalix[4] aromatic hydrocarbon and 1-aminoethyl-3-methylimidazolium bromide molecules, in-situ host-guest self-assembly occurs to form a dense cross-linked network structure of porous supramolecular assembly. The interior and surface of the film are constructed with uniform and dense porous supramolecular assemblies, forming a physical barrier, which significantly enhances the stability of the perovskite film in a high humidity environment and passivates the lead and halogen defects in the perovskite; at the same time, the cavity structure unique to the 4-sulfonyl calix[4] aromatic supramolecular can form a strong interaction with the uncoordinated lead ions and halogen vacancies in the perovskite, significantly inhibiting ion migration behavior, improving the crystallization of the perovskite film, and forming larger grains with fewer defects; thus, compared with the perovskite film prepared by the traditional spin coating method, the perovskite film modified by the porous supramolecular assembly can still maintain its original structure after being placed at about 50% humidity for 600 hours, and the photoelectric conversion efficiency can be increased to 26.17% after being assembled into a photovoltaic cell; thus, this application improves the crystallization of the perovskite film by modifying it with porous supramolecular assembly, thereby improving the quality of the perovskite film and solving the technical problems of the efficiency bottleneck and low stability of the perovskite film.

[0045] The following will describe in detail the preparation method of a porous supramolecular assembly modified perovskite thin film provided in this application, with reference to embodiments and experimental examples.

[0046] Experimental Example 1

[0047] To investigate the porous supramolecular assembly prepared by the reaction of 4-sulfonylcalix[4] aromatic supramolecular and 1-aminoethyl-3-methylimidazolium bromide, this experimental example 1 characterizes the structure of 4-sulfonylcalix[4] aromatic supramolecular, 1-aminoethyl-3-methylimidazolium bromide and the porous supramolecular assembly of their reaction product.

[0048] A schematic diagram of the reaction between 4-sulfonylcalix[4] aromatic supramolecular and 1-aminoethyl-3-methylimidazolium bromide is shown below. Figure 2As shown, the process of preparing porous supramolecular assemblies by reaction includes: dissolving 1 mg of 4-sulfonylcalix[4] aromatic supramolecular in 1 mL of dimethylformamide, then adding 1 mg or 2 mg of 1-aminoethyl-3-methylimidazolium bromide, heating and stirring at 100 °C for 30 min, then filtering and washing with ethanol, and vacuum drying for several hours to obtain a white solid powder, which is the preparation of porous supramolecular assemblies.

[0049] Subsequently, porous supramolecular assemblies obtained by reacting 4-sulfonylcalix[4] aromatic supramolecular molecules, 4-sulfonylcalix[4] aromatic supramolecular molecules and 1-aminoethyl-3-methylimidazolium bromide in a mass ratio of 1:1, and 4-sulfonylcalix[4] aromatic supramolecular molecules and 1-aminoethyl-3-methylimidazolium bromide in a mass ratio of 1:2 were added to dimethylformamide, ultrasonically dispersed, and then spin-coated onto a silicon wafer substrate to prepare samples for scanning electron microscopy analysis. The characterization results are as follows: Figure 3 Figures (a), (b), and (c) show that when 4-sulfonylcalix[4] aromatic supramolecular molecules are dissolved in dimethylformamide, they do not crosslink to form porous supramolecular assemblies. However, with the addition of 1-aminoethyl-3-methylimidazolium bromide, 4-sulfonylcalix[4] aromatic supramolecular molecules undergo host-guest self-assembly with 1-aminoethyl-3-methylimidazolium bromide, forming porous supramolecular assemblies. Furthermore, as the amount of 1-aminoethyl-3-methylimidazolium bromide increases from 1 mg to 2 mg, the crosslinked network structure of the porous supramolecular assemblies becomes more compact. When 2 mg of 1-aminoethyl-3-methylimidazolium bromide is added to a dimethylformamide solution containing 1 mg of 4-sulfonylcalix[4] aromatic supramolecular molecules, the resulting reaction product is a white solid powder. The infrared spectrum and nuclear magnetic resonance hydrogen spectrum of the porous supramolecular assembly show that, compared with... Figure 4 Compared with 1-aminoethyl-3-methylimidazolium bromide, the 4-sulfonylcalix[4] aromatic supramolecular assembly in the infrared spectrum showed significant shifts in the C=N double bond peak (~1600nm), NH stretching peak (~1650nm), and S=O stretching peak (~1200nm). This shift indicates that the two are not simply physically mixed, but rather self-assembled into a supramolecular assembly through interactions between functional groups such as hydrogen bonds and electrostatic interactions. Figure 5 The 1H NMR spectrum also shows that the supramolecular assembly underwent a proton chemical shift, indicating that the two components formed a supramolecular assembly through non-covalent bonds. This also explains... Figure 3 The cross-linked network structure in the electron microscope image; through Figure 2-5It can be seen that during the reaction of 4-sulfonylcalix[4] aromatic supramolecular and 1-aminoethyl-3-methylimidazolium bromide, the positive charge distributed on the conjugated system of the imidazole ring can form an ion pair with the deprotonated sulfonate group through ion exchange. At the same time, the amino group at the end of the side chain can undergo proton exchange with the sulfonic acid group, that is, the sulfonic acid group releases a proton H. + The proton can be paired with the amino group at the end of the side chain, and since the 4-sulfonylcalix[4]arene supramolecular has multiple sulfonic acid groups, its proton transfer and ion pair formation can occur at multiple sites; the 4-sulfonylcalix[4]arene supramolecular and 1-aminoethyl-3-methylimidazolium bromide interact to form a dense cross-linked network structure supramolecular assembly, which plays a physical barrier role on the one hand, and the unique cavity structure of the 4-sulfonylcalix[4]arene supramolecular, forming a cyclic ordered cavity structure, can also improve the crystallization of perovskite films and form larger grains with fewer defects.

[0050] Example 1

[0051] As can be seen from Experiment 1, the porous supramolecular assembly obtained by reacting 4-sulfonylcalix[4] aromatic supramoleculars and 1-aminoethyl-3-methylimidazolium bromide at a mass ratio of 1:2 has a more compact cross-linked network structure. Therefore, the porous supramolecular assembly modified perovskite film prepared in this embodiment uses a porous supramolecular assembly modified perovskite film obtained by reacting 4-sulfonylcalix[4] aromatic supramoleculars and 1-aminoethyl-3-methylimidazolium bromide at a mass ratio of 1:2. The preparation method provided in this embodiment includes the steps of preparing perovskite film raw materials, preparing the doped modified perovskite precursor solution, preparing the assembly monomer solution, spin coating and annealing. The flowchart is shown in Figure 1. Figure 1 As shown.

[0052] The steps for preparing perovskite thin film raw materials include:

[0053] According to the ABX3 perovskite structure, 800 mg of lead iodide, 237 mg of formamidine iodide, 26 mg of methylammonium iodide, 23 mg of cesium iodide, and 10 mg of methylammonium chloride were weighed to obtain the perovskite film precursor composition.

[0054] The preparation steps for the doped and modified perovskite precursor solution include:

[0055] The weighed perovskite film precursor components and 1 mg of 4-sulfonylcalix[4] aromatic hydrocarbon were dissolved together in a mixed organic solvent of 0.8 mL formamide and 0.2 mL dimethyl sulfoxide to obtain a supramolecular doped modified perovskite precursor solution.

[0056] The steps for preparing the monomer solution include:

[0057] 1 mg of the ionic liquid of 1-aminoethyl-3-methylimidazolium bromide was added to 1 mL of chlorobenzene and stirred to obtain a 1 mg / mL assembly monomer solution.

[0058] The spin coating and annealing steps include:

[0059] 50 μL of supramolecular-doped modified perovskite precursor solution was pipetted onto an FTO conductive glass substrate and then spin-coated at 1000 rpm for 15 s to obtain a supramolecular-doped modified perovskite wet film. During the spin-coating process, 100 μL of assembly monomer solution was added and then spin-coated at 5000 rpm for 30 s. The film was then annealed at 100 °C for 30 min to obtain a porous supramolecular assembly modified perovskite film.

[0060] Example 2

[0061] This embodiment provides a method for preparing a perovskite thin film modified by a 4-sulfonylcalix[4]aromatic supramolecular. The difference from Example 1 is that a 4-sulfonylcalix[4]aromatic supramolecular is used to modify the perovskite thin film. The preparation method includes the steps of preparing perovskite thin film raw materials, preparing a solution of doped and modified perovskite precursor, preparing an antisolvent, spin coating and annealing.

[0062] The steps for preparing perovskite thin film raw materials include:

[0063] According to the ABX3 perovskite structure, 800 mg of lead iodide, 237 mg of formamidine iodide, 26 mg of methylammonium iodide, 23 mg of cesium iodide, and 10 mg of methylammonium chloride were weighed to obtain the perovskite film precursor composition.

[0064] The preparation steps for the doped and modified perovskite precursor solution include:

[0065] The weighed perovskite film precursor components and 1.5 mg of 4-sulfonylcalix[4] aromatic hydrocarbon were dissolved together in a mixed organic solvent of 0.2 mL formamide and 0.8 mL dimethyl sulfoxide to obtain a supramolecular doped modified perovskite precursor solution.

[0066] The steps for preparing the antisolvent include:

[0067] Measure 1 mL of chlorobenzene for later use.

[0068] The spin coating and annealing steps include:

[0069] 50 μL of supramolecular doped perovskite precursor solution was pipetted and dropped onto the substrate. Then, a spin coater was used to spin coat the substrate at 1000 rpm for 15 s to obtain a supramolecular doped perovskite wet film. During the spin coat, 100 μL of antisolvent was added and the substrate was spin coated at 5000 rpm for 30 s. The substrate was then annealed at 100 °C for 30 min to obtain a 4-sulfonyl calix [4] aromatic supramolecular modified perovskite film.

[0070] Comparative Example 1

[0071] This comparative example provides a method for preparing a perovskite thin film. The difference between this method and Example 1 is that 4-sulfonylcalix[4]arene and 1-aminoethyl-3-methylimidazolium bromide were not used for modification. The method includes the steps of preparing perovskite thin film raw materials, preparing perovskite precursor solution, preparing antisolvent, spin coating and annealing.

[0072] The steps for preparing perovskite thin film raw materials include:

[0073] According to the ABX3 perovskite structure, 800 mg of lead iodide, 237 mg of formamidine iodide, 26 mg of methylammonium iodide, 23 mg of cesium iodide, and 10 mg of methylammonium chloride were weighed to obtain the perovskite film precursor composition.

[0074] The preparation steps for the perovskite precursor solution include:

[0075] The weighed perovskite film precursor components were dissolved in a mixed organic solvent of 0.8 mL formamide and 0.2 mL dimethyl sulfoxide and stirred to obtain a perovskite precursor solution.

[0076] The steps for preparing the antisolvent include:

[0077] Measure 1 mL of chlorobenzene for later use.

[0078] The spin coating and annealing steps include:

[0079] 50 μL of perovskite precursor solution was pipetted onto an FTO conductive glass substrate and then spin-coated at 1000 rpm for 15 s to obtain a perovskite wet film. During the spin-coating process, 100 μL of antisolvent was added and then spin-coated at 5000 rpm for 30 s. The film was then annealed at 100 °C for 30 min to obtain a perovskite thin film.

[0080] Experimental Example 2

[0081] This experiment characterizes the structure of the perovskite film modified by the porous supramolecular assembly provided in Example 1, the perovskite film modified by the 4-sulfonyl calix [4] aromatic hydrocarbon supramolecular assembly provided in Example 2, and the titanium film provided in Comparative Example 1.

[0082] Field emission scanning electron microscopy (FEM) analysis was performed on the perovskite film modified with the porous supramolecular assembly provided in Example 1, the perovskite film modified with the 4-sulfonyl calix [4] aromatic hydrocarbon supramolecular assembly provided in Example 2, and the titanium film provided in Comparative Example 1. The electron microscopy images are shown below. Figure 6 As shown; from Figure 6 It can be seen that, compared with the perovskite film provided in Comparative Example 1, the perovskite film modified by 4-sulfonylcalix[4]arene supramolecular in Example 2 has fewer defects and higher crystal quality. The perovskite film provided in Example 1 was modified with supramolecular assembly, which can form a dense cross-linked network structure of porous supramolecular assembly protective layer. At the same time, the cavity structure unique to 4-sulfonylcalix[4]arene supramolecular can form a strong interaction with the uncoordinated lead ions and halogen vacancies in the perovskite. It can be clearly observed that the lead iodide is significantly reduced, thereby significantly improving the crystal quality of the perovskite.

[0083] X-ray diffraction analysis was performed on the perovskite film modified with the porous supramolecular assembly provided in Example 1, the perovskite film modified with the 4-sulfonyl calix [4] aromatic hydrocarbon supramolecular assembly provided in Example 2, and the titanium film provided in Comparative Example 1. The X-ray diffraction patterns are shown below. Figure 7 As shown; from Figure 7 It can be seen that, compared with the perovskite film provided in Comparative Example 1, the perovskite film modified by 4-sulfonyl calix [4] aromatics in Example 2 and the perovskite film modified by porous supramolecular assembly in Example 1 have enhanced main peak (100) at 14.1°, suppressed lead iodide labeling peak at 12.7°, and the perovskite film modified by porous supramolecular assembly in Example 1 has higher intensity at 14.1°, which further proves that the crystallinity of the film is improved.

[0084] Experimental Example 3

[0085] As can be seen from Experiment 1 and Experiment 2, the perovskite film modified by the 4-sulfonyl calix [4] aromatic supramolecular provided in Example 2 has higher crystal quality than the perovskite film modified by the porous supramolecular assembly provided in Example 1. Furthermore, this experiment further characterizes the structure and properties of the perovskite film modified by the porous supramolecular assembly provided in Example 1 and the perovskite film provided in Comparative Example 1.

[0086] from Figure 8 As shown in the atomic force microscopy images, compared with the perovskite film provided in Comparative Example 1, the perovskite film modified by the porous supramolecular assembly provided in Example 1 has lower roughness, better flatness, and improved crystallinity; and from... Figure 9As shown in the phase angle images, the perovskite film provided in Comparative Example 1 is mainly located at -30°, while the perovskite film modified with porous supramolecular assemblies provided in Example 1 shows a significant increase to -5° at the grain boundaries, indicating that the formed porous supramolecular assemblies are mainly distributed at the perovskite grain boundaries. Furthermore, from... Figure 10 As shown in the in-situ UV-Vis absorption spectrum during annealing, compared with the perovskite film provided in Comparative Example 1, the perovskite film modified by the porous supramolecular assembly provided in Example 1 broadens its absorption peak to about 795 nm more slowly after heating for 20 seconds. This indicates that the incorporation of supramolecular assemblies can delay the crystallization growth of perovskite crystals, thereby facilitating the formation of larger grains with fewer defects.

[0087] The perovskite film provided in Comparative Example 1 and the perovskite film modified with the porous supramolecular assembly provided in Example 1 were placed in an atmospheric environment with a humidity of 50 ± 3% for 600 hours. The degradation behavior of the perovskite film crystals was analyzed using X-ray diffraction and field emission scanning electron microscopy. The results are as follows: Figure 11-12 As shown; from Figure 11 As shown in the field emission scanning electron microscope images, after the perovskite film was placed in an atmospheric environment with a humidity of 50±3% for 300 and 600 hours, the crystal structure of the perovskite film provided in Comparative Example 1 was significantly damaged, while the perovskite film modified by the porous supramolecular assembly provided in Example 1 could still maintain its original microstructure well. This indicates that the dense supramolecular assembly formed by the in-situ host-guest self-assembly of 4-sulfonylcalix[4]arene and imidazole molecules can construct a uniformly distributed and dense supramolecular assembly inside and on the surface of the perovskite film, forming a physical barrier and significantly enhancing the stability of the perovskite film in a high humidity environment; at the same time Figure 12 The X-ray diffraction pattern shown also shows that, compared with the perovskite film provided in Comparative Example 1, the perovskite film modified by the porous supramolecular assembly provided in Example 1 maintains a high intensity at 14.1° corresponding to the (100) main peak of the black phase perovskite, indicating that the yellow phase perovskite that is prone to precipitate at 11.7° under high humidity conditions has been effectively suppressed.

[0088] Experiment Example 4

[0089] Based on the perovskite film structure and performance characterization provided in Experimental Examples 1, 2 and 3, this experiment assembles the perovskite film modified by the porous supramolecular assembly provided in Example 1, the perovskite film modified by the 4-sulfonyl calix [4] aromatic supramolecular assembly provided in Example 2 and the titanium film provided in Comparative Example 1 into perovskite photovoltaic cells for performance testing.

[0090] Performance testing includes photoelectric conversion efficiency and external quantum efficiency testing, and the results are as follows: Figure 13-14 As shown; from Figure 13The photoelectric conversion efficiency test results shown indicate that, under standard illumination conditions (100mW / cm²), the efficiency is significantly higher than that under standard illumination conditions. 2 Under standard illumination conditions (100mW / cm²), 2 Under the following conditions, the perovskite photovoltaic cell with the perovskite film provided in Comparative Example 1 as the light-absorbing layer has a photoelectric conversion efficiency of 24.26%. The perovskite film provided in Example 2, after being modified with 4-sulfonylcalix[4] aromatic supramolecular, can improve the photoelectric conversion efficiency of the perovskite photovoltaic cell. The perovskite film provided in Example 1, after being modified with supramolecular assembly, can significantly improve the photoelectric conversion efficiency of the perovskite photovoltaic cell to 26.17%. Figure 14 The external quantum efficiency (EQE) test results show that, in the wavelength range of 200-800 nm, modifying the perovskite film with supramolecular assemblies can make the perovskite photovoltaic cell more efficient in utilizing photons, convert more incident photons into photogenerated carriers, resulting in a higher external quantum efficiency (EQE), more efficient light absorption and carrier separation / transmission processes, and a larger integrated current.

[0091] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for preparing a porous supramolecular assembly-modified perovskite thin film, characterized by, The method comprises the following steps: According to the ABX3 perovskite structure, corresponding halide lead, halide formamidinium, methyl halide ammonium and halide cesium are weighed; The weighed halide lead, halide formamidinium, methyl halide ammonium and halide cesium and 4-sulfonyl calix[4] arene supramolecule are dissolved in mixed organic solvents to obtain a supramolecule doped modified perovskite precursor solution; 1-amine ethyl-3-methyl imidazole bromide salt is dissolved in a mixed organic solvent corresponding to an anti-solvent to obtain an assembly monomer solution; The supramolecule doped modified perovskite precursor solution is spin-coated on a substrate to obtain a supramolecule doped modified perovskite wet film; The assembly monomer solution is spin-coated on the surface of the supramolecule doped modified perovskite wet film, and annealing is performed to obtain a porous supramolecular assembly modified perovskite thin film; The mass ratio of 4-sulfonyl calix[4] arene supramolecule in the supramolecule doped modified perovskite precursor solution to 1-amine ethyl-3-methyl imidazole bromide salt in the assembly monomer solution is 1:1-5; The reaction formula in which the 4-sulfonyl calix[4] arene supramolecule and the 1-amine ethyl-3-methyl imidazole bromide salt react to form a porous supramolecular assembly is as follows: 。 2. The method for preparing a porous supramolecular assembly-modified perovskite thin film according to claim 1, characterized in that, The annealing temperature is 80-120°C, and the annealing time is 20-40 minutes.

3. The method for preparing a porous supramolecular assembly-modified perovskite thin film according to claim 1, characterized in that, The solute halide lead in the supramolecule doped modified perovskite precursor solution is selected from at least one of lead iodide, lead bromide and lead chloride; The solute halide formamidinium is selected from at least one of formamidinium iodide, formamidinium bromide and formamidinium chloride; The solute methyl halide ammonium is selected from at least one of methylammonium iodide, methylammonium bromide and methylammonium chloride; The solute halide cesium is selected from at least one of cesium iodide, cesium bromide and cesium chloride.

4. The method for preparing a porous supramolecular assembly-modified perovskite thin film according to claim 3, characterized in that, The concentration of the solute lead iodide is 800 mg / mL, the concentration of the solute formamidinium iodide is 237 mg / mL, the concentration of the solute methylammonium iodide is 26 mg / mL, the concentration of the solute methylammonium chloride is 10 mg / mL, and the concentration of the solute cesium iodide is 23 mg / mL.

5. The method for preparing a porous supramolecular assembly-modified perovskite thin film according to claim 1, characterized in that, The concentration of the solute 4-sulfonyl calix[4] arene supramolecule in the supramolecule doped modified perovskite precursor solution is 0.5-2.5 mg / mL.

6. The method for preparing a porous supramolecular assembly-modified perovskite thin film according to claim 1, characterized in that, The concentration of the 1-amine ethyl-3-methyl imidazole bromide salt in the assembly monomer solution is 0.5-2.5 mg / mL.

7. The method for preparing a porous supramolecular assembly-modified perovskite thin film according to claim 1, characterized in that, The mixed organic solvent is formamidinium and dimethyl sulfoxide in a volume ratio of 4:1, and the anti-solvent is chlorobenzene.

8. A porous supramolecular assembly-modified perovskite thin film, characterized by, Prepared by the preparation method of any one of claims 1-7.

9. A perovskite photovoltaic cell, characterized in that, The porous supramolecular assembly modified perovskite thin film of claim 8.

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