Perovskite precursor solution, perovskite thin film, perovskite battery and preparation method thereof

Abstract

The invention relates to a perovskite precursor solution, a perovskite thin film, a perovskite battery and a preparation method thereof, and belongs to the technical field of perovskite batteries. The perovskite precursor solution comprises a perovskite material, an additive containing multiple sulfonyl chloride groups and an organic solvent, the chemical formula of the additive containing multiple sulfonyl chloride groups is shown in the specification, wherein R1 and R2 are independently selected from C1-6 alkyl, alkenyl, alkynyl, cycloalkyl, phenyl, five-membered heteroaryl, six-membered heteroaryl or ether. By introducing an additive containing a multi-sulfonyl chloride group into a perovskite precursor solution, regulation and control of perovskite crystallization kinetics and multi-site synergistic passivation of bulk phase and grain boundary defects are realized, so that the photoelectric conversion efficiency and long-term operation stability of the perovskite solar cell are comprehensively improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of perovskite batteries, and particularly relates to a perovskite precursor solution, a perovskite thin film, a perovskite battery and a preparation method thereof. BACKGROUND

[0002] With the continuous growth of global energy demand and the emphasis on environmental protection, the development and utilization of clean energy has become an important issue in today's world. Among the many clean energies, solar energy is considered one of the most promising energies in the future due to its unlimited resources, wide distribution, and no pollution emissions. Solar cells, as a key device for converting solar energy into electrical energy, play a crucial role in promoting the large-scale application of solar energy.

[0003] From the first generation of silicon-based solar cells to the second generation of thin-film solar cells, and now to the third generation of perovskite solar cells, which is currently attracting much attention, solar cell technology is constantly evolving. The first generation of silicon-based solar cell technology is mature and has high conversion efficiency, but the production cost is relatively high; the second generation of thin-film solar cell uses less material, has low cost and can achieve flexible application, but the conversion efficiency is relatively insufficient. The third generation of perovskite solar cell stands out with its low cost, simple preparation, and rapid improvement of photoelectric conversion efficiency, and has become a research hotspot.

[0004] Currently, the preparation of perovskite solar cells mainly focuses on the preparation of high-quality perovskite thin films by solution method. The existing technology mainly adopts two strategies to optimize the film quality: one is to improve the physical morphology of the film by regulating the crystallization kinetics, and the other is to improve the electronic properties of the film by passivating defects.

[0005] In terms of crystallization kinetics regulation, researchers have developed various methods, among which the introduction of chloride additives is the most classic and widely used strategy. For example, adding compounds containing chlorine ions such as methylammonium chloride to the precursor solution can interact with the perovskite precursor to form an intermediate phase with lower solubility or greater stability. This not only slows down the formation rate of the perovskite phase, effectively inhibiting the formation of pinholes in the film and the generation of low-dimensional phases, but also provides a longer nucleation and growth window period for the crystal, thereby promoting the formation of larger grains and denser films, ultimately achieving the purpose of improving the charge transport ability of the film and the photoelectric conversion efficiency of the device. However, since perovskite material is an ionic crystal, various intrinsic defects such as uncoordinated lead ions, halogen vacancies, and dangling bonds at grain boundaries will inevitably occur during its crystallization process. These intrinsic defects act as "traps" that capture carriers, causing non-radiative recombination of carriers, which seriously affects the open-circuit voltage and fill factor of the device, limiting the performance improvement of perovskite solar cells.

[0006] To solve this problem, defect passivation technology has emerged. This defect passivation technology mainly uses the rich electron functional groups in Lewis base molecules to form coordination bonds with defect sites as Lewis acids in perovskite to passivate electron traps. Different functional groups have different passivation methods:

[0007] Passivation based on carbonyl (C=O) functional groups: A. Ullah et al. introduced acetoacetylaniline (AAA) containing carbonyl and amide groups as a multifunctional additive. The carbonyl group in the AAA molecule can form strong coordination with uncoordinated lead ions in perovskite, effectively passivating lead defects and suppressing non-radiative recombination, thereby enhancing the photoluminescence intensity of the film, prolonging the carrier lifetime, and significantly improving the device efficiency.

[0008] Passivation based on amino (-NH2) functional groups: J. Li et al. used 3-aminopropyltrimethoxysilane (APMS) as an additive. The amino group not only forms a coordination bond with uncoordinated lead ions, but also stabilizes iodine ions through hydrogen bonding (N-H…I). This dual passivation reduces the defect density at the perovskite grain boundary, reduces charge recombination, and improves the photoelectric conversion efficiency of the device.

[0009] Passivation based on sulfur oxygen (S=O) functional groups: He et al. found that the S=O double bond in the sulfonyl group (-SO2-) of molecules such as diphenyl sulfone can form strong coordination with uncoordinated lead ions, passivate surface defects, optimize interface energy level arrangement, promote hole transport, and improve device efficiency and stability in humid heat environments.

[0010] However, the above techniques still have some drawbacks that restrict the further improvement of device performance. For example, although Lewis base additives such as diphenyl sulfone and acetoacetylaniline can reduce the density of some defect states through chemical passivation, their ability to regulate the crystallization process is limited, making it difficult to precisely control the crystal growth kinetics. Therefore, it is difficult to simultaneously optimize the film morphology, crystallinity, and defect states, and often requires a trade-off between crystallization regulation and defect passivation. In addition, the grain boundaries and surface regions of perovskite films, especially polycrystalline films, are rich in various structural defects and uncoordinated ions. However, most Lewis base additives have relatively simple molecular structures, providing limited chemical passivation sites. For example, diphenyl sulfone can only form point-to-point coordination passivation with a single lead ion defect. Due to the variety and uneven distribution of defects within the film, this "single-point passivation" mode is likely to leave unpassivated defect sites, leading to increased non-radiative recombination, shortened carrier lifetime, and severely affected device performance and long-term stability, making it difficult to meet the needs of high-efficiency and high-reliability perovskite devices.

[0011] Based on this, the present application is proposed. SUMMARY

[0012] To this end, the technical problem to be solved by the present application is to overcome the problems in the prior art that the perovskite thin film has poor crystal quality, high defect density, and serious non-radiative recombination, and the existing additive has single function and incomplete passivation effect.

[0013] To solve the above technical problems, the present application provides a perovskite precursor solution, a perovskite thin film, a perovskite battery and a preparation method thereof. By introducing an additive containing a polysulfonyl chloride group into the perovskite precursor solution, the crystallization kinetics of the perovskite is regulated and the multi-site synergistic passivation of the bulk phase and grain boundary defects is achieved, thereby comprehensively improving the photoelectric conversion efficiency and long-term operation stability of the perovskite solar cell.

[0014] The first object of the present application is to provide a perovskite precursor solution, comprising a perovskite material, an additive containing a polysulfonyl chloride group, and an organic solvent.

[0015] The chemical formula of the additive containing a polysulfonyl chloride group is shown as formula (I) or formula (II):

[0016]

[0017] wherein R1 and R2 are independently selected from C 1-6 alkyl, alkenyl, alkynyl, cycloalkyl, phenyl, five-membered heteroaryl, six-membered heteroaryl or ether group.

[0018] In an embodiment of the present application, the additive containing a polysulfonyl chloride group is selected from one or more of 4,4'-oxybis(benzenesulfonyl chloride) 4,4'-diphenyl disulfonyl chloride 4,4'-methylenebis(benzenesulfonyl chloride) o-benzenedisulfonyl chloride 1,3-benzenedisulfonyl chloride 1,4-benzenedisulfonyl chloride 1,3,5-benzenetrisulfonyl chloride 2,5-dichlorothiophene 3,5-dichloropyridine and 2,6-dichloropyridine

[0019] In an embodiment of the present application, the perovskite material is selected from ABX3, wherein A is selected from one or more of formamidinium ion, methylamine ion and cesium ion, B is selected from lead ion and / or tin ion; X is selected from one or more of iodine ion, bromine ion and chlorine ion.

[0020] In an embodiment of the present application, the organic solvent is selected from N,N-dimethylformamide (DMF) and / or dimethyl sulfoxide (DMSO). ​

[0021] In one embodiment of the present application, the concentration of the perovskite material in the perovskite precursor solution is 1.0 mol / L-1.8 mol / L, and the concentration of the additive containing polysulfonyl chloride groups is 0.1 mg / mL-5.0 mg / mL.

[0022] A second object of the present application is to provide a perovskite thin film prepared from the perovskite precursor solution.

[0023] A third object of the present application is to provide a perovskite battery comprising one or more of a transparent conductive substrate, a hole transport layer, a perovskite layer, an interface passivation layer, an electron transport layer, a buffer layer, and a metal electrode layer arranged in sequence; the perovskite layer is the perovskite thin film.

[0024] In one embodiment of the present application, the material of the transparent conductive substrate is selected from FTO conductive film glass or ITO conductive film glass;

[0025] The material of the hole transport layer is selected from one or more of (2-(3,6-dimethyl-9H-carbazol-9-yl)ethyl)phosphonic acid (Me-2PACz), (2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl)phosphonic acid (MeO-2PACz), (2-(9H-carbazol-9-yl)ethyl)phosphonic acid (2PACz), (4-(3,6-dimethoxy-9H-carbazol-9-yl)butyl)phosphonic acid (MeO-4PACz), (4-(3,6-dimethyl-9H-carbazol-9-yl)butyl)phosphonic acid (Me-4PACz), and a polymer SAM;

[0026] The material of the interface passivation layer is selected from one or more of phenethylammonium iodide (PEAI), 2-phenethylamine hydrochloride (PEACl), phenethylammonium bromide (PEABr), piperazine dihydroiodide (PipI2), and piperazine monohydroiodide (PipI);

[0027] The material of the electron transport layer is fullerene (C 60 );

[0028] The material of the buffer layer is tin oxide (SnO x );

[0029] The material of the metal electrode layer is selected from one or more of silver, gold, and copper.

[0030] In one embodiment of the present application, the thickness of the hole transport layer is 1 nm-6 nm;

[0031] The thickness of the perovskite layer is 400 nm-1200 nm;

[0032] The thickness of the interface passivation layer is 1-5 nm;

[0033] The thickness of the electron transport layer is 15-30 nm;

[0034] The thickness of the buffer layer is 5-25 nm;

[0035] The thickness of the metal electrode layer is 100-150 nm.

[0036] A fourth object of the present application is to provide a preparation method of the perovskite battery, which comprises sequentially preparing a hole transport layer, a perovskite layer, an interface passivation layer, an electron transport layer, a buffer layer and a metal electrode layer on a transparent conductive substrate to obtain the perovskite battery.

[0037] The technical solution of the present application has the following advantages compared with the prior art:

[0038] (1) The perovskite precursor solution of the present application introduces an additive containing a polysulfonyl chloride group, which can realize two key functions through a single molecular component: on the one hand, it precisely controls the crystallization kinetics of the perovskite during the transition from the solution phase to the solid film, stabilizes the intermediate complex of perovskite and solvent, reduces the nucleation rate, promotes the uniform growth and high preferential orientation of the crystal grains, thereby improving the compactness and flatness of the film; on the other hand, it performs multi-site synergistic passivation on the bulk phase and grain boundary defects of the finally formed perovskite film, effectively reduces the deep level defect state density, suppresses non-radiative recombination, and improves the open circuit voltage and energy conversion efficiency. In addition, multi-site synergistic passivation also hinders ion migration and interface degradation path, significantly enhancing the stability of the device under light, thermal stress and humidity environment.

[0039] (2) The perovskite precursor solution described in the present application introduces an additive containing a polysulfonyl chloride group, which can form stable chemical bonds with multiple uncoordinated lead ions and other defect sites at the same time, similar to the "chelation effect" in chemistry, thereby achieving more efficient and more comprehensive defect coverage and stronger anchoring effect, greatly inhibiting non-radiative recombination. In addition, the geometric configuration and flexibility of the molecular skeleton of the additive containing a polysulfonyl chloride group play a key role in the passivation effect. Taking 4,4'-oxybis(benzenesulfonyl chloride) as an example, the ether bond (-O-) in the center of the molecule gives it a unique flexible "V" type symmetric structure. The flexibility of this structure allows it to freely adjust the distance and angle between the two sulfonyl chloride groups, thereby better adapting to the irregularly distributed defect sites on the perovskite lattice surface. This excellent structural adaptability minimizes steric hindrance, allowing it to efficiently form stable bidentate chelation coordination bonds with two or more defect sites, achieving more thorough and more comprehensive "multi-point synergistic" passivation effect. Therefore, the present application not only fully utilizes the synergistic passivation advantage of the polysulfonyl chloride group, but also achieves the best matching with the perovskite defect interface through its unique molecular configuration.

[0040] (3) The unique electronic structure of the sulfonyl chloride group in the perovskite thin film described in the present application is the basis of its dual functionality, in which the strong electron-withdrawing group (-SO2-) acts as a Lewis acid site to regulate the intermediate phase stability, while the oxygen and chlorine atoms act as Lewis base sites to form stable coordination bonds with uncoordinated lead and / or tin ions. This "integrated" solution fundamentally improves the crystalline quality and electronic properties of the perovskite thin film, systematically enhancing the photoelectric conversion efficiency and long-term operational stability of the perovskite solar cell, laying a solid foundation for achieving high short-circuit current density and high fill factor device performance. BRIEF DESCRIPTION OF DRAWINGS

[0041] In order to make the content of the present application easier to be clearly understood, the present application will be further described in detail below according to specific embodiments of the present application and in conjunction with the accompanying drawings, in which:

[0042] Figure 1 is a schematic diagram of the perovskite cell in Example 1 of the present application;

[0043] Figure 2 is a current density-voltage curve diagram of the perovskite cells of Example 1 and Comparative Examples 1-2 in Test Example 1 of the present application;

[0044] Figure 3 is a simulated adsorption diagram of 4,4'-oxybis(benzenesulfonyl chloride) in Example 1 and benzenesulfonyl chloride in Comparative Example 2 in Test Example 2 of the present application on the perovskite surface and lead iodide end combination;

[0045] Figure 4Simulated adsorption profile of 4,4'-oxybis(benzenesulfonyl chloride) in Example 1 and benzenesulfonyl chloride in Comparative Example 2 in Test Example 2 of the present invention on the perovskite surface in combination with formamidinium iodide;

[0046] Figure 5 Simulated adsorption profile of 4,4'-oxybis(benzenesulfonyl chloride) in Example 1 and benzenesulfonyl chloride in Comparative Example 2 in Test Example 2 of the present invention on the perovskite interlayer;

[0047] Figure 6 PL spectra of perovskite layers of Example 1, 5, 7-9 and Comparative Examples 1-2 in Test Example 3 of the present invention;

[0048] Figure 7 Scanning electron microscope images of perovskite layers of Example 1 and Comparative Examples 1-2 in Test Example 4 of the present invention;

[0049] Figure 8 X-ray diffraction patterns of perovskite layers of Example 1 and Comparative Examples 1-2 in Test Example 5 of the present invention;

[0050] Figure 9 XPS Pb 4f test pattern of perovskite layers of Example 1 and Comparative Example 1 in Test Example 6 of the present invention

[0051] Figure 10 XPS N 1s test pattern of perovskite layers of Example 1 and Comparative Example 1 in Test Example 7 of the present invention;

[0052] Figure 11 X-ray diffraction patterns of perovskite layers of Example 1 and Comparative Example 1 in Test Example 8 of the present invention under different annealing time conditions;

[0053] Figure 12 TPV pattern of perovskite cells of Example 1 and Comparative Example 1 in Test Example 9 of the present invention;

[0054] Figure 13 TRPL pattern of perovskite layers of Example 1 and Comparative Example 1 in Test Example 10 of the present invention;

[0055] Figure 14 Stability change trend pattern of perovskite cells of Example 1 and Comparative Example 1 in Test Example 11 of the present invention. DETAILED DESCRIPTION

[0056] The present invention will be further described with reference to the drawings and specific examples, so that those skilled in the art can better understand the present invention and implement it, but the examples are not intended to limit the present invention.

[0057] In the present application, unless otherwise specified, the transparent conductive substrate used in the embodiments of the present application is ITO conductive film glass, which needs to be cleaned before use. The cleaning process specifically includes the following steps: sequentially placing the ITO conductive film glass in cleaning agents (detergent E, available from Shengong Bioengineering (Shanghai) Co., Ltd., product number A510780-0100), deionized water, acetone and ethanol for ultrasonic cleaning, respectively for 60 min; after cleaning, the ITO conductive film glass surface is dried with nitrogen and surface activation treatment is performed using ultraviolet ozone for 20 min.

[0058] In the present application, unless otherwise specified, the (4-(3,6-dimethyl-9H-carbazol-9-yl)butyl)phosphonic acid (Me-4PACz) used in the embodiments of the present application is purchased from TCI (Shanghai) Chemical Industry Development Co., Ltd., product code M3359.

[0059] Example 1

[0060] Referring to Figure 1 The perovskite battery and the preparation method thereof of the present application specifically include the following steps:

[0061] S1, preparation of a hole transport layer: (4-(3,6-dimethyl-9H-carbazol-9-yl)butyl) phosphonic acid is dissolved in anhydrous ethanol to prepare a hole transport layer solution with a concentration of 0.5 mg / mL; the hole transport layer solution is spin-coated on a transparent conductive substrate using a spin coating method, the spin coating speed is 3000 rpm, and the spin coating time is 30 s; after spin coating, the sample is subjected to annealing treatment, the annealing temperature is 100°C, and the time is 10 min, forming a uniform and dense hole transport layer with a thickness of 2 nm.

[0062] S2, preparation of a perovskite layer: lead iodide, formamidinium iodide, cesium iodide and methylamine iodide are dissolved in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide with a volume ratio of 4:1 according to a molar ratio of 1:0.90:0.05:0.05, then 4,4'-oxybis(benzenesulfonyl chloride) is added and stirred uniformly to prepare a perovskite material FA 0.90 MA 0.05 Cs 0.05The perovskite precursor solution has a PbI3 concentration of 1.4 mol / L and a 4,4'-oxybis(benzenesulfonyl chloride) concentration of 0.5 mg / mL; the perovskite precursor solution is spin-coated on the hole transport layer using a two-step spin-coating procedure; the first step is low-speed spin-coating at 2000 rpm for 10 s; the second step is high-speed spin-coating at 4000 rpm for 30 s; before the end of the second step, anti-solvent chlorobenzene is added dropwise to the surface of the sample; after spin-coating is completed, the sample is subjected to multi-stage annealing treatment, first annealing at 100 ℃ for 60 min, and then annealing at 150 ℃ for 10 min, to ensure complete solvent evaporation and high-quality crystallization of the perovskite film, forming a perovskite layer with a thickness of 700 nm.

[0063] S3, preparation of an interface passivation layer: phenethylammonium iodide is dissolved in isopropanol to prepare an interface passivation layer solution with a concentration of 5 mg / mL; the interface passivation layer solution is spin-coated on the perovskite layer at a speed of 4000 rpm for 30 s; after spin-coating is completed, the sample is subjected to annealing treatment at an annealing temperature of 100 ℃ for 10 min, to form an interface passivation layer with a thickness of 2 nm.

[0064] S4, preparation of an electron transport layer: a 25-nm-thick C 60 electron transport layer is deposited on the surface of the interface passivation layer at an evaporation rate of 0.02 nm / s.

[0065] S5, preparation of a buffer layer: high-purity (99.9999%) tetrakis(dimethylamino) tin (IV) and deionized water are used as precursors to deposit a 10-nm-thick SnO x buffer layer on the surface of the electron transport layer by ALD process at 90 ℃.

[0066] S6, preparation of a silver electrode layer: a 100-nm-thick silver electrode layer is deposited on the surface of the buffer layer by evaporation at an evaporation rate of 0.1 nm / s through a mask, to obtain a perovskite battery.

[0067] Example 2

[0068] The basic procedure is the same as in Example 1, except that the concentration of 4,4'-oxybis(benzenesulfonyl chloride) in the perovskite precursor solution is 0.25 mg / mL.

[0069] Example 3

[0070] The basic procedure is the same as in Example 1, except that the concentration of 4,4'-oxybis(benzenesulfonyl chloride) in the perovskite precursor solution is 0.75 mg / mL.

[0071] Example 4

[0072] The same as Example 1, except that the concentration of 4,4'-oxybis(benzenesulfonyl chloride) in the perovskite precursor solution was 1.0 mg / mL.

[0073] Example 5

[0074] The same as Example 1, except that 4,4'-oxybis(benzenesulfonyl chloride) in the perovskite precursor solution was replaced by 4,4'-biphenyl disulfonyl chloride.

[0075] Example 6

[0076] The same as Example 1, except that 4,4'-oxybis(benzenesulfonyl chloride) in the perovskite precursor solution was replaced by 4,4'-methylenebis(benzenesulfonyl chloride).

[0077] Example 7

[0078] The same as Example 1, except that 4,4'-oxybis(benzenesulfonyl chloride) in the perovskite precursor solution was replaced by 1,3,5-benzene trisulfonyl chloride.

[0079] Example 8

[0080] The same as Example 1, except that 4,4'-oxybis(benzenesulfonyl chloride) in the perovskite precursor solution was replaced by 2,5-dithiophene disulfonyl chloride.

[0081] Example 9

[0082] The same as Example 1, except that 4,4'-oxybis(benzenesulfonyl chloride) in the perovskite precursor solution was replaced by 3,5-pyridine disulfonyl chloride.

[0083] Comparative Example 1

[0084] The same as Example 1, except that 4,4'-oxybis(benzenesulfonyl chloride) was not added in the perovskite precursor solution.

[0085] Comparative Example 2

[0086] The same as Example 1, except that 4,4'-oxybis(benzenesulfonyl chloride) in the perovskite precursor solution was replaced by benzenesulfonyl chloride.

[0087] Test Example 1

[0088] The open-circuit voltage V OC , short-circuit current density J sc , fill factor FF and energy conversion efficiency PCE of the perovskite cells prepared in Examples 1-7 and Comparative Examples 1-2 were tested by current density-voltage curve, and the test conditions were: AM 1.5G standard solar spectrum, irradiance of 1000 W / m2 .

[0089] Figure 2 and the relevant performances of the final measured perovskite cells are shown in Table 1:

[0090] Table 1

[0091]

[0092]

[0093] From Figure 2 As can be seen from Table 1, the perovskite cells of the embodiments all exhibit significant performance improvement, especially the PCE of Example 1 reaches 26.39%. This performance improvement is mainly attributed to the dual advantages of the additive in crystallization regulation and multi-site defect passivation. First, the additive containing multiple sulfonyl chloride groups forms stable coordination bonds with defects such as uncoordinated lead ions in the perovskite through its multiple Lewis base sites (such as oxygen, chlorine atoms), effectively inhibiting non-radiative recombination loss, thereby maximizing the retention of photo-generated carriers and significantly improving the open-circuit voltage (V OC ). Second, the additive containing multiple sulfonyl chloride groups delays the crystallization rate by complexing with the precursor, providing more sufficient time for crystal growth, forming a thin film with larger grain size, fewer defects and higher density. This high-quality thin film reduces resistance loss and interface recombination in the charge transport process, thereby greatly improving the fill factor (FF). The simultaneous improvement of the open-circuit voltage (V OC ) and the fill factor (FF) ultimately realizes a huge leap in the energy conversion efficiency (PCE), fully confirming the effectiveness of the additive containing multiple sulfonyl chloride groups in crystallization regulation and multi-site defect passivation.

[0094] As can be seen from Examples 1-4, when the concentration of the additive is within a certain range, the key photovoltaic parameters of the perovskite cell are all relatively excellent. When the concentration is too low, the number of additive molecules is insufficient to cover a large number of defect sites (especially grain boundaries and surfaces) in the perovskite thin film, and the passivation effect is not good; this makes a large number of non-radiative recombination centers exist, limiting the improvement of the open-circuit voltage (V OC ) and the fill factor (FF), and further leading to a low overall efficiency of the device. When the concentration is too high, excessive additive molecules will become "impurities", which will form new scattering centers or defect states at the grain boundaries, hinder charge transport, and increase the series resistance, thereby reducing the FF and the photoelectric conversion efficiency (PCE). In addition, excessive additives will also excessively change the crystallization kinetics, making the thin film morphology deviate from the optimal state.

[0095] As can be seen from Example 1 and Examples 5-7, 4,4'-diphenyl disulfonyl chloride, 4,4'-methylenebis(benzenesulfonyl chloride) and 1,3,5-benzene trisulfonyl chloride, 4,4'-oxo-bis(benzenesulfonyl chloride) have a significant impact on the final performance of perovskite cells, and the performance of different additives containing polysulfonyl chloride groups is slightly different, which also shows that the molecular configuration of the additive, especially its flexibility, symmetry and spatial geometry, plays a key role in determining the passivation efficiency and film quality.

[0096] As can be seen from Comparative Example 1 and Example 1, without adding additives, the open-circuit voltage, fill factor and overall energy conversion efficiency of the perovskite cell are significantly reduced. This is because without the regulation of additives, the crystallization process of perovskite is very rapid and difficult to control, resulting in poor film quality, such as small grain size, high grain boundary density, a large number of pinholes and lead iodide residues on the surface. These morphological defects seriously hinder the effective transport of charges and increase the series resistance, thereby greatly reducing the fill factor (FF). At the same time, a large number of grain boundaries and surface defects (such as uncoordinated lead ions) become efficient non-radiative recombination centers, trapping photo-generated carriers and making them lose in the form of heat energy, which directly leads to a significant decrease in the open-circuit voltage (V OC ) and a shortening of the carrier lifetime. OC The simultaneous reduction of V

[0097] As can be seen from Comparative Example 1 and Comparative Example 2, when using benzenesulfonyl chloride as an additive, the open-circuit voltage, fill factor and overall energy conversion efficiency of the perovskite cell are significantly reduced. This is because benzenesulfonyl chloride, as a single sulfonyl chloride group additive, has much lower passivation ability and crystallization regulation effect than additives containing polysulfonyl chloride groups. Specifically, benzenesulfonyl chloride can only form a "point-to-point" coordination passivation with a single sulfonyl chloride group and a single defect site (such as a single uncoordinated lead ion); in the face of a large number of and complex distribution of defects on the surface and grain boundaries of the perovskite film, this single-point passivation mode is inefficient and cannot achieve full coverage, and a large number of defects remain unpassivated and continue to act as non-radiative recombination centers, thereby limiting the improvement of V OC and FF. In contrast, 4,4'-oxo-bis(benzenesulfonyl chloride) of Example 1 can achieve "multi-point synergistic passivation" through its two sulfonyl chloride groups, forming a more stable and more comprehensive chelation effect, thereby more effectively inhibiting non-radiative recombination.

[0098] Test Example 2

[0099] To theoretically reveal the interaction mechanism between the additive and the perovskite surface, first-principle calculations based on density functional theory (DFT) were adopted, and all calculations were completed by the VASP software package. In the calculation, a 3x3x2 surface supercell was constructed based on the cubic phase FAPbI3, and the PBE exchange correlation functional and D3 dispersion correction were used to describe the system. The interaction strength between the additive and the perovskite surface was evaluated by calculating the adsorption energy (Eb = E (slab + molecule) - E (slab) - E (molecule)), and the DFT simulation diagram is shown in Figures 3-5 As can be seen from Figure 3 , the binding energy of the additive containing a multi-sulfonyl chloride group in Example 1 (4,4'-oxybis(benzenesulfonyl chloride)) to the lead iodide end (-1.11 eV) is significantly stronger than that of the additive containing a single sulfonyl chloride group in Comparative Example 2 (benzenesulfonyl chloride) (-0.69 eV); this indicates that the additive of Example 1 can more firmly anchor the lead ion defect site on the perovskite surface, achieving more effective passivation. As can be seen from Figure 4 , the binding energy of the additive containing a multi-sulfonyl chloride group in Example 1 to the formamidinium iodide end (-0.87 eV) is also higher than that of the additive containing a single sulfonyl chloride group in Comparative Example 2 (-0.48 eV). Further analysis of the charge density difference confirms that the additive of Example 1 can form a stable hydrogen bond with the formamidinium cation, while the additive of Comparative Example 2 mainly relies on weak van der Waals forces; this indicates that the additive of Example 1 can more effectively stabilize the organic cation, reducing its migration and loss. As can be seen from Figure 5 , the additive containing a multi-sulfonyl chloride group in Example 1 can achieve three-site coordination with the perovskite lattice by virtue of its flexible structure, with a binding energy as high as -2.38 eV; while the additive containing a single sulfonyl chloride group in Comparative Example 2 can only achieve two-site coordination, with a binding energy of -1.53 eV; this indicates that the additive of Example 1 has better structural adaptability and defect passivation potential inside the crystal, and can simultaneously interact with multiple defect sites, forming a powerful "molecular anchoring" effect. In summary, the DFT simulation results theoretically confirm the huge advantages of the additive containing a multi-sulfonyl chloride group in terms of binding strength, multi-site synergistic effect, and structural adaptability.

[0100] Test Example 3

[0101] Based on Examples 1, 5, 7-9 and Comparative Examples 1-2, photoluminescence (PL) spectrum tests were performed on the perovskite layer using a fluorescence spectrometer, and the recombination of carriers in the perovskite layer was indirectly represented by the photoluminescence intensity, and the PL spectrum test results are shown in Figure 6 As can be seen from Figure 6As can be seen, the perovskite layer of the embodiment exhibits excellent photoluminescence intensity, and the PL peak value is significantly higher than that of Comparative Example 1 (without additive) and Comparative Example 2 (with additive containing monosulfonyl chloride groups). A higher PL intensity indicates a lower defect state density and better suppression of nonradiative recombination. This directly demonstrates that the additive containing monosulfonyl chloride groups has the most outstanding effect in passivating defects and reducing carrier loss, which is closely related to the significant increase in device open-circuit voltage and the extension of carrier lifetime.

[0102] Test Example 4

[0103] Scanning electron microscopy characterization of the perovskite layer was performed based on Example 1 and Comparative Examples 1-2, and the results are as follows: Figure 7 As shown. From Figure 7 It can be seen that the perovskite layer of Example 1 has the largest and most uniform grains and the smoothest and densest surface, and effectively suppresses the precipitation of lead iodide, resulting in the best film quality. This is because the additive containing polysulfonyl chloride groups significantly slows down the crystallization kinetics by forming a stable intermediate complex with lead iodide in the precursor. This slow and orderly crystallization process promotes the merging of crystal nuclei and the full growth of grains, ultimately forming a high-quality film with large-sized micron-sized grains, a smooth surface without pinholes, and no lead iodide residue. The excellent film morphology provides an ideal physical basis for efficient charge transport and suppression of interfacial recombination. In contrast, the perovskite layer of Comparative Example 1 has smaller grains and obvious lead iodide residue. This is because, without the additive, the perovskite crystallization process is too fast, resulting in the simultaneous formation of a large number of crystal nuclei, which do not have enough time to grow, thus forming a film with small grains and high-density grain boundaries. The perovskite layer of Comparative Example 2 has larger grains, but still has pinholes and lead iodide residue, indicating that the additive containing monosulfonyl chloride groups in Comparative Example 2 has limited control over crystallization.

[0104] Test Example 5

[0105] X-ray diffraction tests were performed on the perovskite layers based on Example 1 and Comparative Examples 1-2, and the results are as follows: Figure 8 As shown. From Figure 8 It can be seen that the main diffraction peak (100) of the perovskite layer in Example 1 is the sharpest and its peak intensity is significantly enhanced, while the characteristic diffraction peak of lead iodide at 12.7° is completely suppressed. Comparative Example 2 shows the next best effect, and Comparative Example 1 shows the worst effect. This indicates that the perovskite layer in Example 1 has the highest crystallinity and phase purity, and the crystallinity quality of the material is significantly improved. This further demonstrates the key role of additives containing polysulfonyl chloride groups in regulating crystallization kinetics and promoting the formation of high-quality perovskite films.

[0106] Test Example 6

[0107] Based on Example 1 and Comparative Example 1, the perovskite layer was subjected to XPS Pb 4f test to determine the interaction between the additive and the uncoordinated lead ion through the change of Pb element binding energy, and the XPS Pb 4f test results are shown in Figure 9 As can be seen from Figure 9 , compared with Comparative Example 1, the Pb 4f peak position of the perovskite layer of Example 1 obviously shifts to the low binding energy direction, indicating that the electron cloud density around the lead ion increases, which confirms that the additive containing multiple sulfonyl chloride groups in Example 1 forms a stable coordination bond with the uncoordinated lead ion, effectively passivating the defects.

[0108] Test Example 7

[0109] Based on Example 1 and Comparative Example 1, the perovskite layer was subjected to XPS N 1s test to determine the interaction between the additive and the organic cation through the change of N element binding energy, and the XPS N 1s test results are shown in Figure 10 As can be seen from Figure 10 , compared with Comparative Example 1, the N 1s binding energy of the perovskite layer of Example 1 decreases from 400.6 eV to 400.4 eV, indicating that the local chemical environment of the FA + cation changes, confirming that the additive containing multiple sulfonyl chloride groups in Example 1 forms a hydrogen bond with the organic cation, thereby playing a role in stabilizing the lattice.

[0110] Test Example 8

[0111] Based on Example 1 and Comparative Example 1, the perovskite layer under different annealing time (first stage annealing treatment) conditions was subjected to X-ray diffraction test to determine the crystallization kinetics process through the duration of the intermediate phase diffraction peak, and the X-ray diffraction test results are shown in Figure 11 As can be seen from Figure 11 , the intermediate phase diffraction peak of the perovskite layer of Example 1 is more stable and persistent (about 6 s after disappearance in the example, and about 4 s after disappearance in Comparative Example 1), indicating that the introduction of the additive containing multiple sulfonyl chloride groups significantly delays and stabilizes the conversion of the precursor intermediate phase, optimizes the nucleation and growth process of the crystal, and helps to form a high-quality film.

[0112] Test Example 9

[0113] The perovskite cells of Example 1 and Comparative Example 1 were subjected to TPV test to evaluate the speed of carrier recombination by measuring the carrier lifetime of the perovskite cell under open circuit condition, and the TPV test results are shown in Figure 12 As can be seen from Figure 12It can be seen that the perovskite cell of Example 1 has a longer carrier lifetime. This is because the additive containing a double sulfonyl chloride group is introduced in Example 1, which effectively passivates the trap defects in the perovskite cell, reducing the non-radiative recombination loss of the carriers at the defects.

[0114] Test Example 10

[0115] Based on the TRPL test of the perovskite layer of Example 1 and Comparative Example 1, the degree of non-radiative recombination in the perovskite layer is indirectly represented by fitting the average carrier lifetime thereof, and the TRPL test results are shown in Figure 13 Figure 13 It can be seen that the perovskite layer of Example 1 has a longer carrier lifetime, indicating that the defect states in the perovskite layer of Example 1 are effectively passivated, and the non-radiative recombination is significantly inhibited, thereby improving the carrier transport efficiency.

[0116] Test Example 11

[0117] The perovskite cells of Example 1 and Comparative Example 1 were subjected to stability tests, and the change in the photoelectric conversion efficiency of the perovskite cell under 1 sun light intensity for 1100h of continuous light (test environment: 40±5℃, 35%-45%RH) was tested, and the test results are shown in Figure 14 Figure 14 It can be seen that the efficiency of the perovskite cell of Example 1 maintains 96% of its initial efficiency throughout the test period, while the efficiency of the perovskite cell of Comparative Example 1 decreases significantly over time to 85% of the initial value. It shows that the additive containing a plurality of sulfonyl chloride groups in Example 1 can effectively inhibit performance degradation and significantly improve the long-term running stability of the device.

[0118] Obviously, the above embodiments are only examples for the purpose of clear illustration, and are not a limitation on the embodiments. Based on the above description, other different forms of changes or variations can be made by those of ordinary skill in the art. Here, it is not necessary and impossible to exhaust all embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.​​

Claims

1. A perovskite precursor solution, characterized in that, The perovskite material, the additive containing a plurality of sulfonyl chloride groups, and an organic solvent are included. The chemical formula of the additive containing a plurality of sulfonyl chloride groups is shown as formula (I) or formula (II): wherein R1and R2are independently selected from C 1-6 alkyl, alkenyl, alkynyl, cycloalkyl, phenyl, five-membered heteroaryl, six- membered heteroaryl, or ether.

2. The perovskite precursor solution of claim 1, wherein, The additive containing a plurality of sulfonyl chloride groups is selected from one or more of 4,4'-oxybis(benzenesulfonyl chloride), 4,4'-diphenyl disulfonyl chloride, 4,4'-methylenebis(benzenesulfonyl chloride), o-benzenedisulfonyl chloride, 1,3-benzenedisulfonyl chloride, 1,4-benzenedisulfonyl chloride, 1,3,5-benzenetrisulfonyl chloride, 2,5-dichlorothiophene, 3,5-dichloropyridine, and 2,6-dichloropyridine.

3. The perovskite precursor solution of claim 1, wherein, The perovskite material is selected from ABX3, wherein A is selected from one or more of formamidinium ion, methylamine ion, and cesium ion, B is selected from lead ion and / or tin ion, and X is selected from one or more of iodine ion, bromine ion, and chlorine ion.

4. The perovskite precursor solution of claim 1, wherein, The organic solvent is selected from N,N-dimethylformamide and / or dimethyl sulfoxide.

5. The perovskite precursor solution of claim 1, wherein, The concentration of the perovskite material in the perovskite precursor solution is 1.0 mol / L-1.8 mol / L, and the concentration of the additive containing a plurality of sulfonyl chloride groups is 0.1 mg / mL-5.0 mg / mL.

6. A perovskite thin film, characterized by, The perovskite thin film is prepared from the perovskite precursor solution of any one of claims 1-5.

7. A perovskite cell characterized by, The perovskite battery comprises one or more of a transparent conductive substrate, a hole transport layer, a perovskite layer, an interface passivation layer, an electron transport layer, a buffer layer, and a metal electrode layer, which are sequentially arranged; the perovskite layer is the perovskite thin film of claim 6.

8. The perovskite cell according to claim 7, characterized in that, The material of the transparent conductive substrate is selected from FTO conductive film glass or ITO conductive film glass; The material of the hole transport layer is selected from one or more of (2-(3,6-dimethyl-9H-carbazol-9-yl)ethyl)phosphonic acid, (2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl)phosphonic acid, (2-(9H-carbazol-9-yl)ethyl)phosphonic acid, (4-(3,6-dimethoxy-9H-carbazol-9-yl)butyl)phosphonic acid, (4-(3,6-dimethyl-9H-carbazol-9-yl)butyl)phosphonic acid, and a polymer SAM; The material of the interface passivation layer is selected from one or more of phenethylammonium iodide, 2-phenylethylamine hydrochloride, phenethylammonium bromide, piperazine dihydroiodide, and piperazine monohydroiodide; The material of the electron transport layer is fullerene; The material of the buffer layer is tin oxide; The material of the metal electrode layer is selected from one or more of silver, gold, and copper.

9. The perovskite cell of claim 7, wherein, The thickness of the hole transport layer is 1 nm-6 nm; The thickness of the perovskite layer is 400 nm-1200 nm; The thickness of the interface passivation layer is 1 nm-5 nm; The thickness of the electron transport layer is 15 nm-30 nm; The thickness of the buffer layer is 5 nm-25 nm; The thickness of the metal electrode layer is 100 nm-150 nm.

10. A method of producing a perovskite cell as claimed in any of claims 7-9, characterised in that, The hole transport layer, the perovskite layer, the interface passivation layer, the electron transport layer, the buffer layer, and the metal electrode layer are sequentially prepared on the transparent conductive substrate to obtain the perovskite battery.

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