Perovskite thin film and preparation method and application thereof

Abstract

The invention belongs to the technical field of perovskite batteries, and particularly relates to a perovskite thin film and a preparation method and application thereof. The perovskite thin film is prepared from the following raw materials: a perovskite precursor and a rubidium-based organic hybrid chelate; the rubidium-organic hybrid chelate is prepared from the following raw materials: a rubidium inorganic compound and an organic ligand compound. According to the invention, by introducing a precursor chelate, namely a rubidium-organic hybrid chelate, which is formed by a rubidium-based inorganic compound and an organic ligand compound in a synergistic manner, the synergistic regulation and directional guidance of the perovskite crystallization process are realized, and the thin film with high crystallization quality and low defect density is obtained. And meanwhile, by utilizing the synergistic effect of Rb + lattice anchoring and organic ligand defect passivation, multiple effects of crystal guiding, defect passivation and structure stabilization are realized, and the photoelectric property and the stability of the perovskite device are improved.

Description

Technical Field

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

[0002] As a novel composite functional material, organic-inorganic hybrid perovskites combine the structural diversity of organic materials with the high carrier mobility of inorganic semiconductors. They possess characteristics such as strong light absorption, high extinction coefficient, long carrier diffusion distance, and excellent photoluminescence properties, attracting widespread attention in fields such as lighting displays, photodetectors, and solar cells. Among these, organic-inorganic hybrid perovskite solar cells exhibit excellent photoelectric performance and enormous potential, and as a next-generation photovoltaic device, they have received considerable attention and research from researchers in related fields in recent years.

[0003] While perovskite solar cells possess high efficiency potential, insufficient long-term stability remains a bottleneck, severely hindering their commercialization. The core of this problem lies in the inherent ionization migration and surface defects of the material, and mainstream single-component passivation strategies have limitations: for example, organic passivating agents (such as those containing -COOH or -NH2 molecules) can bind uncoordinated Pb. 2+ However, it cannot suppress halogen vacancies and may hinder charge transport; inorganic additives (such as alkali metal ions) can fill vacancies and inhibit ion migration, but they are ineffective for passivating Pb. 2+ The drawbacks are minimal. Simply mixing the two in a physical way often results in only additive effects due to the lack of synergistic design at the molecular level, and they may even restrict each other due to competing action sites.

[0004] Therefore, it is crucial to develop a novel passivation system that synergistically passivates multiple defects at the molecular level. Summary of the Invention

[0005] The present invention aims to solve one or more technical problems existing in the prior art, and at least provide a beneficial alternative. Specifically, the present invention provides a perovskite thin film with high crystallinity and low defect density, thereby improving the photoelectric performance and stability of perovskite solar cells.

[0006] The inventive concept of this invention: The raw materials for preparing the perovskite thin film of this invention include a perovskite precursor and a rubidium-organic hybrid chelate; the raw materials for preparing the rubidium-organic hybrid chelate include a rubidium-based inorganic compound and an organic ligand compound.

[0007] This invention achieves synergistic regulation and directional guidance of the perovskite crystallization process by introducing a precursor chelate formed synergistically by rubidium-based inorganic compounds and organic ligand compounds, namely a rubidium-organic hybrid chelate, to obtain thin films with high crystal quality and low defect density. Simultaneously, it utilizes "Rb+ The synergistic effect of "lattice anchoring" and "organic ligand defect passivation" achieves multiple effects of "crystallization guidance-defect passivation-structural stability", thereby improving the optoelectronic performance and stability of perovskite devices.

[0008] Therefore, a first aspect of the present invention provides a perovskite thin film.

[0009] Specifically, the raw materials for preparing the perovskite thin film include perovskite precursors and rubidium-organic hybrid chelates;

[0010] The raw materials for preparing the rubidium-organic hybrid chelate include rubidium-based inorganic compounds and organic ligand compounds.

[0011] Specifically, rubidium-organic hybrid chelates achieve functional synergy through unique molecular design: rubidium ions (Rb + Because of its suitable ionic radius, it can effectively fill the A-site vacancies in the perovskite lattice and inhibit halide ion migration; organic ligand compounds interact with uncoordinated Pb through their abundant O, N and other coordinating atoms. 2+ Stable coordination bonds are formed, enabling passivation of deep-level defects. The synergistic effect generated by the chelate structure is far superior to the simple superposition of single-component additives.

[0012] During crystallization, rubidium-organic hybrid chelates guide the orderly growth of perovskite grains. The organic component moderately slows down crystallization kinetics, providing a time window for sufficient grain growth; the inorganic component stabilizes the crystal structure at the lattice level. This dynamic regulation mechanism effectively promotes increased grain size, reduced grain boundaries, and improved film density, resulting in films with high crystallinity and low defect density.

[0013] After crystallization, the rubidium-organic hybrid chelate continues to play a stabilizing role, selectively enriching at grain boundaries and surfaces to form a molecular-level protective network. Among them, Rb... + By inhibiting ion migration, organic ligand compounds provide hydrophobic protection and continuous defect passivation, achieving multiple effects of "crystallization guidance-defect passivation-structural stability" and improving the optoelectronic performance and stability of perovskite devices.

[0014] Preferably, the raw materials for preparing the perovskite precursor include at least two of lead iodide, formamidinium iodide, lead bromide, methylamine bromide, and cesium bromide.

[0015] Preferably, the anion in the rubidium-based inorganic compound is selected from I - ,Br - Cl - SCN - BF4 - PF6 - At least one of them.

[0016] Specifically, the structural formula of the rubidium-based inorganic compound is Rb-X, where X is selected from I - ,Br - Cl - SCN - BF4 - PF6 - At least one of them.

[0017] Preferably, the organic ligand compound comprises compounds with at least one of oxygen atom and nitrogen atom as ligands and which are associated with Rb. + Organic compounds that form chelates.

[0018] Specifically, organic ligand compounds are those that can react with Rb + Organic compounds that form stable chelates contain two or more electron-donating coordinating atoms, with 2-3 atoms spaced between them, forming stable five- or six-membered rings.

[0019] Preferably, the organic ligand compound includes at least one of crown ether organic ligand compounds, polycarboxylic acid organic ligand compounds, amine organic ligand compounds, and amino acids.

[0020] Preferably, the crown ether organic ligand compound includes 18-crown-6-ether.

[0021] Preferably, the polycarboxylic acid organic ligand compound includes citric acid.

[0022] Preferably, the amine organic ligand compound includes at least one of ethylenediamine, ethylenediamine derivatives, and polypyridine.

[0023] Specifically, crown ether organic ligands and polycarboxylic acid organic ligands contain oxygen atom ligands; amine organic ligands contain nitrogen atom ligands; and amino acids contain nitrogen-oxygen mixed ligands.

[0024] Preferably, the molar ratio of the rubidium-based inorganic compound to the organic ligand compound is 1:(0.8-1.2); more preferably, the molar ratio of the rubidium-based inorganic compound to the organic ligand compound is 1:(0.9-1.1); even more preferably, the molar ratio of the rubidium-based inorganic compound to the organic ligand compound is 1:1.

[0025] Preferably, the thickness of the perovskite film is 450-600 nm; for example, 450 nm, 460 nm, 470 nm, 480 nm, 490 nm, 500 nm, 510 nm, 520 nm, 530 nm, 540 nm, 550 nm, 560 nm, 570 nm, 580 nm, 590 nm, 600 nm, etc.

[0026] A second aspect of the present invention provides a method for preparing the perovskite thin film described in the first aspect of the present invention.

[0027] Specifically, the method for preparing the perovskite thin film includes the following steps: The perovskite precursor solution and the rubidium-organic hybrid chelate solution were mixed, coated, and annealed to obtain the product.

[0028] Preferably, the molar amount of rubidium-organic hybrid chelate in the rubidium-organic hybrid chelate solution is 0.5-2.0% of the molar amount of lead ions in the perovskite precursor solution; for example, 0.5%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, etc.

[0029] Specifically, the concentration of the rubidium-organic hybrid chelate solution, expressed as a molar percentage, is 0.5-2.0% of the molar amount of lead ions in the perovskite precursor solution.

[0030] Preferably, the molar concentration of the perovskite precursor solution is 1.4-1.8 M.

[0031] Preferably, the coating includes spin coating.

[0032] Preferably, the spin coating is a segmented spin coating, including a first spin coating segment and a second spin coating segment.

[0033] Preferably, the rotation speed of the first spin coating section is 800-1500 rpm, and the spin coating time of the first section is 8-12 s; more preferably, the rotation speed of the first spin coating section is 900-1100 rpm, and the spin coating time of the first section is 9-11 s.

[0034] Preferably, the spin coating speed of the second stage is 3500-5000 rpm, and the spin coating time of the second stage is 25-35 s; more preferably, the spin coating speed of the second stage is 3800-4500 rpm, and the spin coating time of the second stage is 27-33 s.

[0035] Preferably, the anti-solvent is added dropwise 18-20 seconds after the start of the second spin coating.

[0036] Preferably, the antisolvent includes at least one of chlorobenzene, toluene, ethyl acetate, diethyl ether, and isopropanol; more preferably, the antisolvent includes chlorobenzene.

[0037] Preferably, the method for preparing the titanium ore precursor solution includes the following steps: mixing the raw materials for preparing the titanium ore precursor and the solvent to obtain the solution.

[0038] Preferably, in the preparation of the titanium ore precursor solution, the solvent includes N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO).

[0039] Preferably, the volume ratio of DMF to DMSO is (3-5):1; for example, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, etc.

[0040] Preferably, the mixing is carried out by stirring.

[0041] Preferably, the method for preparing the rubidium-organic hybrid chelate solution includes the following steps: mixing the raw materials for preparing the rubidium-organic hybrid chelate and the solvent, reacting them, and obtaining the solution.

[0042] Preferably, in the preparation of the rubidium-organic hybrid chelate solution, the solvent includes DMSO.

[0043] Preferably, the reaction time is 3-8 hours; more preferably, the reaction time is 3-6 hours; even more preferably, the reaction time is 3 hours.

[0044] A third aspect of the present invention provides a perovskite solar cell.

[0045] Specifically, the perovskite solar cell includes the perovskite thin film described in the first aspect of the present invention.

[0046] Preferably, the perovskite solar cell comprises a transparent conductive substrate, a hole transport layer, a perovskite thin film layer, a passivation layer, an electron transport layer, and a metal electrode layer stacked sequentially.

[0047] Preferably, the transparent conductive substrate comprises an indium tin oxide glass layer (ITO glass layer).

[0048] Compared with the prior art, the beneficial effects of the technical solution provided by the present invention are as follows: (1) This invention achieves synergistic regulation and directional guidance of the perovskite crystallization process by introducing a precursor chelate formed synergistically by rubidium-based inorganic compounds and organic ligand compounds, namely, a rubidium-organic hybrid chelate, to obtain a thin film with high crystal quality and low defect density. Simultaneously, it utilizes "Rb +The synergistic effect of "lattice anchoring" and "organic ligand defect passivation" achieves multiple effects of "crystal guidance-defect passivation-structural stability," improving the photoelectric performance and stability of perovskite devices. Specifically, the absolute value of the photoelectric conversion efficiency (PCE) of perovskite solar cells can be increased by more than 2.5%; the open-circuit voltage (Voc) is increased by 50-70mV, a significant voltage increase indicating a significant reduction in defect density; simultaneously, the fill factor is optimized, increasing by 3-5 percentage points, indicating improved film quality. Furthermore, the hysteresis index decreases from 7-9% to below 1.5%, demonstrating effective suppression of ion migration and a fundamental improvement in stability.

[0049] (2) The process of this invention is simple and fully compatible with existing preparation processes, requiring no complicated post-processing steps; at the same time, the process has strong compatibility: good results can be obtained in various perovskite systems such as FAPbI3, mixed cations, and wide bandgap.

[0050] (3) This invention provides a reliable material solution for the development of perovskite solar cells, especially tandem cells, and has broad prospects for industrial application. Detailed Implementation

[0051] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.

[0052] Unless otherwise specified, the raw materials, reagents or devices used in the following examples are available from conventional commercial sources or can be obtained by existing known methods.

[0053] Example 1 This embodiment provides a method for fabricating a perovskite solar cell, the specific steps of which are as follows: (1) The cleaned ITO glass was treated with ultraviolet light and ozone for 20 minutes to obtain the substrate; (2) Prepare a DMF solution of 0.5 mg / mL organic small molecule [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACZ), take 50 μL and spin coat it onto the substrate obtained in step (1) at a speed of 3000 rpm, 1500 rpm / s, and 30 s. After spin coating, anneal at 100 °C for 10 min to complete the preparation of the hole transport layer film with a thickness of about 2 nm. (3) Preparation of perovskite thin film: Take 100 μL of perovskite solution on the hole transport layer obtained in step (2) and spin coat it in two stages at rotation speeds of 1000 rpm, 1000 rpm / s, 10s and 4000 rpm, 2000 rpm / s, 30s. Add 180 μL of chlorobenzene (CB) at the 18th second of the second spin coating and then quickly transfer it to a hot stage at 100℃ for annealing for 15 min to obtain a perovskite thin film with a thickness controlled at 550±10 nm. (4) Take 50 μL of 0.3 mg / mL phenylethylamine iodide (PEAI) in isopropanol (IPA) solution and spin coat it onto the perovskite film obtained in step (3) at a speed of 4500 rpm, 2000 rpm / s, and 30 s. After spin coating, anneal at 80 °C for 5 min to complete the preparation of the passivation layer. The thickness is controlled at about 4 nm. (5) For the electron transport layer (ETL), below 10 -4 Under high vacuum conditions, 20 nm of C60 was thermally evaporated onto the passivation layer; subsequently, a 12 nm buffer layer of SnO2 was deposited using atomic layer deposition (ALD) (100 cycles, chamber at 100 °C, tetra(dimethylamine)tin (TDMASn) source at 70 °C, 1.2 s pulse, 5 s purge, H2O at 20 °C, 1 s pulse, 5 s purge, 90 sccm carrier gas N2) to obtain the electron transport layer; (6) On the electron transport layer, a single-junction perovskite device was fabricated by vacuum evaporation of 120 nm Ag as a metal electrode at a deposition rate of 1 Å / s.

[0054] In step (3), the perovskite solution is prepared as follows: Chelate preparation: RbI and 18-crown-6-ether were dissolved in DMSO solvent at a molar ratio of 1:1 and stirred at 60°C for 3 h. Then, the mixture was aged at room temperature in the dark for 12 h to form a mother liquor of RbI-18-crown-6-ether chelate with a rubidium ion concentration of 0.1 M. Perovskite precursor solution: Weigh 645.4 mg of lead iodide (PbI2) and 240.8 mg of formamidinium iodide (FAI) and add them to a bottle containing a mixed solvent of 0.8 mL DMF and 0.2 mL DMSO. Stir for 7 h to obtain a uniform and transparent 1.4 M FAPbI3 perovskite precursor solution. 1.0 mol% RbI-18-crown-6-ether chelate mother liquor (chelate concentration is relative to Pb in perovskite precursor solution) 2+ The concentration was calculated, i.e., the molar percentage of RbI-18-crown-6-ether chelate was 1% of the molar percentage of lead ions in the perovskite precursor solution. The solution was added to the perovskite precursor solution, stirred until fully dissolved, and then filtered through a 0.22 μm PTEE filter to obtain the final product.

[0055] In addition, the following control group was set up for comparison with Example 1.

[0056] Control group 1: No 1.0 mol% RbI-18-crown-6-ether chelate stock solution was added to the perovskite solution, otherwise the same as in Example 1.

[0057] Control group 2: 1.0 mol% RbI was added to the perovskite solution to replace the 1.0 mol% RbI-18-crown-6-ether chelate mother liquor, and the rest was the same as in Example 1.

[0058] Control group 3: 1.0 mol% 18-crown-6-ether was added to the perovskite solution to replace the 1.0 mol% RbI-18-crown-6-ether chelate mother liquor, and the rest was the same as in Example 1.

[0059] Control group 4: 1.0 mol% KI-18-crown-6-ether chelate stock solution was added to the perovskite solution to replace the 1.0 mol% RbI-18-crown-6-ether chelate stock solution, and the rest was the same as in Example 1.

[0060] The preparation process of the KI-18-crown-6-ether chelate mother liquor is as follows: KI and 18-crown-6-ether are dissolved in DMSO solvent at a molar ratio of 1:1, stirred at 60℃ for 3h, and then aged at room temperature in the dark for 12h to form a KI-18-crown-6-ether chelate mother liquor with a potassium ion concentration of 0.1M.

[0061] Example 2 Example 2 provides an application of RbSCN-citric acid chelate in mixed cationic perovskites. Specifically, the preparation method of the mixed cationic perovskite in Example 2 is as follows: (1)-(2) Same as Example 1; (3) Preparation of perovskite thin film: Take 100 μL of perovskite solution on the hole transport layer obtained in step (2) and spin coat it in two stages at rotation speeds of 1000 rpm, 1000 rpm / s, 10s and 4500 rpm, 2000 rpm / s, 30s. Add 180 μL of chlorobenzene (CB) at the 18th second of the second spin. Then quickly transfer it to a hot stage at 100℃ and anneal for 15 min to obtain a perovskite thin film with a thickness controlled at 480±10 nm. (4)-(6) Same as Example 1.

[0062] In step (3), the perovskite solution is prepared as follows: Chelate preparation: RbSCN and citric acid monohydrate were dissolved together in DMSO at a molar ratio of 1:1 and stirred continuously at 60°C for 3 hours. Then, the mixture was aged at room temperature in the dark for 12 hours. After cooling, a mother liquor of RbSCN-citric acid chelate with a rubidium ion concentration of 0.1 M was formed. Preparation of perovskite precursor solution (perovskite composition (FAPbI3)) 0.9 (MAPbBr3) 0.1 ): Weigh 580.9 mg lead iodide (PbI2), 51.4 mg lead bromide (PbBr2), 216.7 mg formamidin iodine (FAI) and 15.7 mg methylamine bromide (MABr), add them to a bottle containing 0.8 mL DMF and 0.2 mL DMSO mixed solvent, stir for 4 h to obtain a uniform and transparent perovskite precursor solution; The 1.0 mol% RbSCN-citric acid chelate mother liquor was added to the perovskite precursor solution, stirred until fully dissolved, and then filtered through a 0.22 μm PTEE filter to obtain the solution.

[0063] In addition, the following control group was set up for comparison with Example 2.

[0064] Control group 5: No 1.0 mol% RbSCN-citric acid chelate mother liquor was added to the perovskite solution, otherwise the same as in Example 2.

[0065] Control group 6: 1.0 mol% RbSCN was added to the perovskite solution to replace the 1.0 mol% RbSCN-citric acid chelate mother liquor, and the rest was the same as in Example 2.

[0066] Control group 7: 1.0 mol% citric acid monohydrate was added to the perovskite solution to replace the 1.0 mol% RbSCN-citric acid chelate mother liquor, and the rest was the same as in Example 2.

[0067] Control group 8: 1.0 mol% KSCN-citric acid chelate mother liquor was added to the perovskite solution to replace 1.0 mol% RbSCN-citric acid chelate mother liquor, and the rest was the same as in Example 2.

[0068] The preparation process of KSCN-citric acid chelate mother liquor is as follows: KSCN and citric acid monohydrate are dissolved in DMSO solvent at a molar ratio of 1:1, stirred at 60℃ for 3h, and then aged at room temperature in the dark for 12h to form KSCN-citric acid chelate mother liquor with a concentration of 0.1M based on potassium ions.

[0069] Example 3 Example 3 provides an application of RbPF6-4,4'-bipyridine chelate in wide-bandgap perovskites. Specifically, the preparation method of the wide-bandgap perovskite in Example 3 is as follows: (1)-(2) Same as Example 1; (3) Preparation of perovskite thin film: Take 100 μL of perovskite solution on the hole transport layer obtained in step (2) and spin coat it in two stages at rotation speeds of 1500 rpm, 1500 rpm / s, 10 s and 5000 rpm, 2000 rpm / s, 30 s. Add 180 μL of chlorobenzene (CB) at the 18th second of the second spin. Then quickly transfer it to 70 °C for annealing for 2 min, and then transfer it to a hot stage at 100 °C for annealing for 15 min to obtain a perovskite thin film with a thickness controlled at 520 ± 10 nm. (4)-(6) Same as Example 1.

[0070] In step (3), the perovskite solution is prepared as follows: Chelate preparation: RbPF6 and 4,4'-bipyridine were dissolved together in DMSO at a molar ratio of 1:1. The solution was stirred continuously at 60°C for 3 h, then cooled to room temperature and aged for 12 h to obtain a mother liquor of RbPF6-4,4'-bipyridine chelate with a rubidium ion concentration of 0.1 M. Preparation of perovskite precursor solution (perovskite composition (FAPbI3)) 0.8 (MAPbBr3) 0.15 (CsPbBr3) 0.05 : Weigh out 663.8 mg of lead iodide (PbI2), 132.1 mg of lead bromide (PbBr2), 247.55 mg of formamidinium iodide (FAI), 19.2 mg of cesium bromide (CsBr), and 30.23 mg of methylamine bromide (MABr), and add them to a bottle containing a mixed solvent of 0.8 mL DMF and 0.2 mL DMSO. Stir for 7 h to obtain 1.8 M (FAPbI3). 0.8 (MAPbBr3) 0.15 (CsPbBr3) 0.05 Perovskite precursor solution; The 1.0 mol% RbPF6-4,4'-bipyridine chelate mother liquor was added to the perovskite precursor solution, stirred until fully dissolved, and then filtered through a 0.22 μm PTEE filter to obtain the product.

[0071] In addition, the following control group was set up for comparison with Example 3.

[0072] Control group 9: No 1.0 mol% RbPF6-4,4'-bipyridine chelate mother liquor was added to the perovskite solution, otherwise the same as in Example 3.

[0073] Control group 10: 1.0 mol% RbPF6 was added to the perovskite solution to replace the 1.0 mol% RbPF6-4,4'-bipyridine chelate mother liquor, and the rest was the same as in Example 3.

[0074] Control group 11: 1.0 mol% 4,4'-bipyridine was added to the perovskite solution to replace the 1.0 mol% RbPF6-4,4'-bipyridine chelate mother liquor, and the rest was the same as in Example 3.

[0075] Control group 12: 1.0 mol% KPF6-4,4'-bipyridine chelate stock solution was added to the perovskite solution to replace 1.0 mol% RbPF6-4,4'-bipyridine chelate stock solution, and the rest was the same as in Example 3.

[0076] The preparation process of the KPF6-4,4'-bipyridine chelate mother liquor is as follows: KPF6 and 4,4'-bipyridine are dissolved in DMSO solvent at a molar ratio of 1:1, stirred at 60℃ for 3h, then cooled to room temperature and allowed to stand for aging for 12h to form a KPF6-4,4'-bipyridine chelate mother liquor with a concentration of 0.1M based on potassium ions.

[0077] Performance testing The photoelectric performance and stability of the perovskite devices in Examples 1-3 and the control group were tested using the following methods: The experiment used a Keithley B2901BL source measurement instrument and a calibrated EnLi Tech AAA-grade xenon lamp solar simulator. The effective area of ​​a single perovskite solar cell was 0.24 cm². 2 Photomask definition. Test conditions: AM 1.5G spectrum at room temperature, light source calibrated to 100 mW / cm² using standard crystalline silicon. 2 Tests were conducted, and the JV curves of the single-junction solar cell were recorded from 1.3V to -0.2V (forward scan) and -0.2V to 1.3V (reverse scan) within the voltage range, with a step size of 10mV and a delay of 100ms. All photoelectric parameters (JV) were recorded. SC V oc Both FF and PCE are calculated and output directly by the software's built-in algorithm based on the acquired original JV curves.

[0078] The hysteresis index is calculated based on the maximum photoelectric conversion efficiency obtained from both forward and reverse scanning, using the following formula: Hysteresis index = |(PCE) 反扫 -PCE 正扫 )| / max(PCE 正扫 PCE 反扫 Stability is characterized by the hysteresis index.

[0079] The performance test results of perovskite solar cells in Example 1 and Control Groups 1-4 are shown in Table 1.

[0080] Table 1: Performance test results of perovskite solar cells in Example 1 and Control Groups 1-4 Group <![CDATA[V oc (V)]]> <![CDATA[J sc (mA / cm 2 )]]> FF(%) PCE (%) Hysteresis Index Control group 1 1.10 24.5 75.8 20.4 8.2% Control group 2 1.13 24.7 77.2 21.5 4.8% Control group 3 1.12 24.6 76.9 21.2 6.5% Control group 4 1.15 24.1 73.2 20.2 6.0% Example 1 1.17 24.9 81.5 23.7 0.8% The performance test results of the 5-8 perovskite solar cells in Example 2 and the control group are shown in Table 2.

[0081] Table 2: Performance test results of 5-8 perovskite solar cells in Example 2 and the control group Group <![CDATA[V oc (V)]]> <![CDATA[J sc (mA / cm 2 )]]> FF(%) PCE (%) Hysteresis Index Control group 5 1.15 22.4 76.2 19.6 7.5% Control group 6 1.18 22.6 77.8 20.7 3.2% Control group 7 1.17 22.6 77.5 20.5 5.8% control group 8 1.18 22.2 74.8 19.5 6.5% Example 2 1.19 22.8 80.8 21.9 1.2% The performance test results of the 9-12 perovskite solar cells in Example 3 and the control group are shown in Table 3.

[0082] Table 3: Performance test results of 9-12 perovskite solar cells in Example 3 and the control group Group <![CDATA[V oc (V)]]> <![CDATA[J sc (mA / cm 2 )]]> FF(%) PCE (%) Hysteresis Index Control group 9 1.20 19.6 75.5 17.8 9.1% control group 10 1.23 19.5 76.8 18.4 4.5% Control group 11 1.22 19.5 76.2 18.1 6.8% control group 12 1.22 19.2 73.2 17.1 8.5% Example 3 1.27 19.8 79.8 20.1 1.5% Tables 1-3 show the universality and synergistic effect of rubidium-based inorganic-organic hybrid chelates in different perovskite systems. While maintaining consistent film thickness, the addition of rubidium-based inorganic-organic hybrid chelates significantly improved key parameters such as Voc and FF, and essentially eliminated the hysteresis effect, resulting in perovskite solar cells with excellent photoelectric performance and stability.

[0083] As shown in Table 1, under the premise of consistent film thickness, the FF of Example 1 was significantly improved (5.7% higher than that of Control Group 1), indicating that the defects in the film were passivated, indirectly confirming the optimizing effect of the chelate on the crystal morphology. The hysteresis index decreased from 8.2% to 0.8%, indicating that ion migration was effectively suppressed and the stability was greatly improved. Compared with Control Groups 2-3, the Voc of Example 1 was significantly improved (+40-50mV). In Control Group 4, K... + Replace Rb + Afterwards, although the hysteresis was improved (compared to control group 1), the FF of the device was significantly reduced, and the final efficiency was lower than that of the groups with single addition (control groups 2 and 3), indicating that the combination of potassium ions introduced unfavorable lattice stress and impaired charge transport.

[0084] Based on the above analysis, simply Rb + The passivation effect of fillers or organic ligands is limited, while the addition of the rubidium-organic hybrid chelate of the present invention can stabilize the lattice and passivate defects in the thin film, thereby improving the photoelectric performance and stability of perovskite solar cells.

[0085] As can be seen from Table 2, SCN in the chelate - With Pb2+ Strong coordination, combined with Rb + The lattice stabilizing effect of the KcOcOf, FFF, and PCE are improved, while the hysteresis index is significantly reduced. Compared with control group 5, Vc is increased by 40mV, and with the same film thickness, FFF is increased by 4.6%, indicating that the charge collection efficiency is improved. Control group 8 uses KcOf ... + Replace Rb + Subsequently, both Jsc and FF decreased (compared to control group 5), indicating that the synergistic passivation of the potassium ion combination failed.

[0086] As shown in Table 3, under the premise of consistent film thickness, the RbPF6-4,4'-bipyridine chelate improves key parameters such as Jsc, FF and Voc in the wide-bandgap perovskite system, demonstrating the application potential of this strategy in the field of high-efficiency stacking.

[0087] Furthermore, the comparison between Example 1 and Control Group 4, Example 2 and Control Group 8, and Example 3 and Control Group 12 shows that only the combination of rubidium-organic ligand compounds can produce a specific synergistic effect, and it is not a general function of alkali metal ions.

[0088] In summary, this invention achieves synergistic regulation and directional guidance of the perovskite crystallization process by introducing a precursor chelate formed synergistically by a rubidium-based inorganic compound and an organic ligand compound, namely a rubidium-organic hybrid chelate, to obtain a thin film with high crystal quality and low defect density. Simultaneously, it utilizes "Rb + The synergistic effect of "lattice anchoring" and "organic ligand defect passivation" achieves multiple effects of "crystallization guidance-defect passivation-structural stability", thereby improving the optoelectronic performance and stability of perovskite devices.

[0089] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A perovskite thin film, characterized in that, The raw materials for preparing the perovskite thin film include perovskite precursor and rubidium-organic hybrid chelate. The raw materials for preparing the rubidium-organic hybrid chelate include rubidium-based inorganic compounds and organic ligand compounds.

2. The perovskite thin film according to claim 1, characterized in that, The raw materials for preparing the perovskite precursor include at least two of lead iodide, formamidinium iodide, lead bromide, methylamine bromide, and cesium bromide.

3. The perovskite thin film according to claim 1, characterized in that, The anion in the rubidium-based inorganic compound is selected from I - ,Br - Cl - SCN - BF4 - PF6 - At least one of them; And / or, the organic ligand compound comprises compounds with at least one of oxygen atom and nitrogen atom as ligands and which are associated with Rb. + Organic compounds that form chelates.

4. The perovskite thin film according to claim 3, characterized in that, The organic ligand compounds include at least one of crown ether organic ligand compounds, polycarboxylic acid organic ligand compounds, amine organic ligand compounds, and amino acids.

5. The perovskite thin film according to claim 4, characterized in that, The crown ether organic ligand compound includes 18-crown-6-ether; and / or, the polycarboxylic acid organic ligand compound includes citric acid; and / or, the amine organic ligand compound includes at least one of ethylenediamine, ethylenediamine derivatives, and polypyridine.

6. The perovskite thin film according to claim 1, characterized in that, The molar ratio of the rubidium-based inorganic compound to the organic ligand compound is 1:(0.8-1.2).

7. The perovskite thin film according to any one of claims 1-6, characterized in that, The thickness of the perovskite film is 450-600 nm.

8. The method for preparing the perovskite thin film according to any one of claims 1-7, characterized in that, The preparation method includes the following steps: The perovskite precursor solution and the rubidium-organic hybrid chelate solution were mixed, coated, and annealed to obtain the product.

9. The preparation method according to claim 8, characterized in that, The method for preparing the titanium ore precursor solution includes the following steps: mixing the raw materials for preparing the titanium ore precursor and the solvent to obtain the solution; And / or, the method for preparing the rubidium-organic hybrid chelate solution includes the following steps: mixing the raw materials and solvent for preparing the rubidium-organic hybrid chelate, reacting them, and obtaining the solution.

10. A perovskite solar cell, characterized in that, The perovskite solar cell includes the perovskite thin film according to any one of claims 1-7.