A fast self-healing alkoxylated polyethyleneimine material, preparation method and application thereof

Abstract

The application discloses a kind of fast self-repairing alkoxylated polyethylene imine material and preparation method and application, it is related to solar photovoltaic packaging material technical field.The method includes alkoxylated ethenyl imidazole imidazolium double trifluoromethane sulfonimide monomer is dissolved in DMSO solvent, then a certain proportion of initiator is added as initiator, and under the protection of nitrogen atmosphere, radical polymerization reaction is initiated at 70~90 ℃, after multiple washing with ethyl acetate, alkoxylated polyethylene imine material is obtained.The application is based on alkoxylated imidazole monomer, through alkylation reaction, ion exchange reaction and radical polymerization reaction, successfully build alkoxylated polyethylene imine material, while designing to realize the fast self-repairing function of packaging material and the effect of inhibiting lead leakage, finally realize the lossless packaging of solar photovoltaic cell, improve the operating stability of photovoltaic product.

Description

Technical Field

[0001] This invention relates to the field of solar photovoltaic encapsulation materials technology, specifically to a rapidly self-healing alkoxylated polyethyleneimine material, its preparation method, and its applications. Background Technology

[0002] Perovskite photovoltaic cells (PSCs), as a photovoltaic device with great development potential, have attracted widespread attention from researchers due to their advantages such as low manufacturing cost, simple fabrication process, and good compatibility with tandem photovoltaic devices. Although significant breakthroughs have been made in the photoelectric conversion efficiency of perovskite cells, their poor stability still cannot meet the requirements for commercial applications. This is because perovskite cells are subject to chemical degradation of the perovskite thin film induced by the external environment during operation, which severely affects the operational and environmental stability of the device. Therefore, external encapsulation of perovskite solar cells has proven to be an effective way to improve the operational stability of photovoltaic cells.

[0003] Regarding encapsulation materials for perovskite solar cells, widely reported polymer hot melt adhesive film encapsulation materials such as ethylene-vinyl acetate copolymer (EVA) and polyolefin elastomer (POE) typically rely on vacuum hot pressing processes during use. However, related studies have shown that when perovskite devices are encapsulated in a vacuum environment, it can induce ion migration and phase separation within the film, leading to structural damage to the perovskite solar cell. For photocurable encapsulation materials, ultraviolet light curing is usually required during encapsulation, increasing the cost of device encapsulation while the organic vapors released during curing can reduce the device's operational stability. Furthermore, current polymer encapsulation materials are unable to self-repair after damage, resulting in decreased device operational stability and a significantly increased risk of lead leakage. Therefore, from the perspective of device encapsulation, there is an urgent need to develop new encapsulation materials, improve their performance, and optimize encapsulation processes, especially designing polymer encapsulation materials that are inherently stable, have a simple encapsulation process, and can effectively suppress lead leakage, thereby improving the operational stability and environmental friendliness of perovskite solar cells. Summary of the Invention

[0004] To address the shortcomings of existing polymer encapsulation materials in the aforementioned background technology, this invention provides an alkoxylated polyethyleneimine material with rapid self-healing function for external encapsulation of perovskite solar photovoltaic cells, along with its preparation method and applications. This approach is based on alkoxyimidazolium monomers, through alkylation, ion exchange, and free radical polymerization, successfully constructing a cationic polymer—alkoxylated polyethyleneimine (EP). By controlling the types and ratios of alkoxy bromide monomers, the tensile strength and light transmittance of the encapsulation film are adjusted. Simultaneously, the rapid self-healing function and lead leakage suppression effect of the encapsulation material are designed to achieve non-destructive encapsulation of solar photovoltaic cells, improving the operational stability of photovoltaic products. In practical applications, it has been found that perovskite solar devices encapsulated with alkoxylated polyethyleneimine material retain 98.6% of their initial efficiency after aging at 85% relative humidity for 1000 hours, 97.8% after aging at 85°C for 1000 hours, and 97.1% after operating at maximum power point for 1000 hours. Furthermore, after 1000 hours of aging, the lead content on the cell surface is only 0.09 ppm. The preparation method of this alkoxylated polyethyleneimine material and the photovoltaic device packaging scheme help to further improve the operational stability of perovskite cells, and have great development potential and commercial prospects.

[0005] The first objective of this invention is to provide a method for preparing a rapidly self-healing alkoxylated polyethyleneimine material, comprising the following steps: The alkoxyvinylimidazolium bis(trifluoromethanesulfonyl)imide monomer was dissolved in DMSO solvent, and then a certain proportion of initiator was added as an initiator. Under nitrogen atmosphere protection, the free radical polymerization reaction was initiated at 70~90℃. After washing with ethyl acetate multiple times, the alkoxylated polyethyleneimine material was obtained. Preferably, the alkoxyvinylimidazolium bis(trifluoromethanesulfonyl)imide monomer is prepared according to the following steps: An aqueous solution of lithium bis(trifluoromethanesulfonyl)imide was uniformly mixed with alkoxyvinylimidazolium bromide monomer. The mixture was then stirred at room temperature for 12-24 hours, the precipitate was filtered, washed repeatedly with deionized water, and dried under vacuum to obtain alkoxyvinylimidazolium bis(trifluoromethanesulfonyl)imide monomer.

[0006] Preferably, the molar ratio of the alkoxyvinylimidazolium bromide monomer to the lithium bis(trifluoromethanesulfonyl)imide in aqueous solution is 1:1 to 1.5.

[0007] Preferably, the alkoxyvinylimidazolium bromide monomer is prepared according to the following steps: N-vinylimidazolium and alkoxy bromide were dissolved in dimethyl sulfoxide and reacted under nitrogen protection at 80-100°C for 24-72 hours with stirring. After cooling to room temperature, ethyl acetate was added to precipitate the product. The crude precipitate was filtered, dissolved in deionized water, extracted three times with ethyl acetate, and then rotary evaporated to obtain a mixture. After vacuum drying, the alkoxyvinylimidazolium bromide monomer was obtained.

[0008] Preferably, the alkoxy bromide is one of 1-(2-(2-methoxyethoxy)ethyl) bromide, 3-(2-methoxyethoxy)bromopropane, 1-(2-bromoethoxy)-2-ethoxybenzene, and 4-bromo-2-ethoxythiazole; The molar ratio of N-vinylimidazolium to alkoxybromide is 1:1~2.

[0009] Preferably, the initiator is one of azobisisobutyronitrile, azobisisoheptanenitrile, benzoyl peroxide, ammonium persulfate, and potassium persulfate; The mass ratio of the alkoxyvinylimidazolium bis(trifluoromethanesulfonyl)imide monomer to the initiator is 100:1~5.

[0010] The second objective of this invention is to provide a rapidly self-healing alkoxylated polyethyleneimine material.

[0011] The third objective of this invention is to provide an application of a rapidly self-healing alkoxylated polyethyleneimine material in the encapsulation of perovskite solar cells.

[0012] The fourth objective of this invention is to provide a method for encapsulating perovskite solar cells, comprising the following steps: After the rapid self-healing alkoxylated polyethyleneimine material is heated and melted into a transparent liquid, it is uniformly coated on the surface of the perovskite solar cell and then stacked with the cover glass to form a layered structure. The stacked structure is placed in an air environment at 10~60℃ and subjected to a pressure of 20~40 kPa for 10~30 minutes until curing and cross-linking are completed, thus obtaining a fully encapsulated perovskite solar cell device.

[0013] Preferably, the perovskite solar cell comprises conductive glass, a hole transport layer, a perovskite thin film, an electron transport layer, and electrodes stacked sequentially.

[0014] Compared with existing technologies, this invention provides a rapidly self-healing alkoxylated polyethyleneimine material, its preparation method, and its applications, which have the following significant beneficial effects: This invention ensures that the prepared alkoxylated polyethyleneimine (EP) material possesses excellent transparency and mechanical properties by rationally selecting the types of alkoxy bromide monomers and optimizing the proportions between various monomer components. The bis(trifluoromethanesulfonyl)imide ionic group endows the alkoxylated EP material with excellent rapid self-healing capabilities. This not only effectively inhibits damage to perovskite solar cells caused by external factors such as high temperature, humidity, and oxygen, but also enables the encapsulation material to rapidly self-repair cracks after damage. Based on the dual protection of self-healing physical barriers and ion chemical adsorption, the environmental hazards of lead leakage from perovskite devices are effectively avoided. Based on the above-mentioned alkoxylated EP encapsulation material, this invention proposes an application scheme for non-destructive encapsulation of perovskite solar cells, enabling photovoltaic devices to maintain long-term stable performance under extreme conditions such as high temperature, light, and high humidity. This effectively improves the operational stability and environmental friendliness of perovskite photovoltaic devices, promoting the commercialization of perovskite photovoltaic devices.

[0015] The perovskite solar cell encapsulated with the alkoxylated polyethyleneimine material of this invention retains 98.6% of its initial efficiency after aging at 85% relative humidity for 1000 hours, 97.8% after aging at 85°C for 1000 hours, and 97.1% after operating at the maximum power point under continuous standard sunlight irradiation for 1000 hours. In contrast, the perovskite solar cell not encapsulated with the polymer film retains only 16.5% of its initial efficiency after aging at 85% relative humidity for 1000 hours, only 14.2% after aging at 85°C for 1000 hours, and only 13.8% after operating at the maximum power point under continuous standard sunlight irradiation for 1000 hours. These performance data demonstrate that the perovskite solar cell encapsulated with the alkoxylated polyethyleneimine material proposed in this invention possesses excellent long-term stability and broad commercial application prospects, contributing to the industrial application of perovskite solar cells. Attached Figure Description

[0016] Figure 1 The alkoxylated polyethyleneimine material in Example B1 13 C NMR data.

[0017] Figure 2 A schematic diagram of a perovskite solar cell device encapsulated with alkoxylated polyethyleneimine material.

[0018] Figure 3 This is a scanning electron microscope image of the surface of the alkoxylated polyethyleneimine material in Example B1 after encapsulation and curing. Detailed Implementation

[0019] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and accompanying drawings. However, the embodiments described are not intended to limit the present invention.

[0020] The purpose of this invention is to overcome the limitations of existing photocurable encapsulation materials. The encapsulation process typically requires ultraviolet (UV) curing, which increases device encapsulation costs and causes a decrease in device operational stability due to the release of organic vapors during curing. Furthermore, current polymer encapsulation materials cannot self-repair after damage, leading to decreased device operational stability and a significantly increased risk of lead leakage. This invention provides a rapidly self-healing alkoxylated polyethyleneimine (EP) material, its preparation method, and its applications. Based on alkoxyimidazolium monomers, this invention successfully constructs a cationic polymer—alkoxylated polyethyleneimine (EP) material—through alkylation, ion exchange, and free radical polymerization. By controlling the types and ratios of alkoxybrominated monomers, the tensile strength and light transmittance of the encapsulation film are adjusted. Simultaneously, the rapid self-healing function and lead leakage suppression effect of the encapsulation material are designed to be achieved, ultimately realizing non-destructive encapsulation of solar photovoltaic cells and improving the operational stability of photovoltaic products.

[0021] To achieve the above objectives, the first aspect of the present invention provides a method for preparing a rapidly self-healing alkoxylated polyethyleneimine material, comprising the following steps: The alkoxyvinylimidazolium bis(trifluoromethanesulfonyl)imide monomer was dissolved in DMSO solvent, and then a certain proportion of initiator was added as an initiator. Under nitrogen atmosphere protection, the free radical polymerization reaction was initiated at 70~90℃. After washing with ethyl acetate multiple times, the alkoxylated polyethyleneimine material was obtained. The alkoxyvinylimidazolium bis(trifluoromethanesulfonyl)imide monomer is prepared according to the following steps: An aqueous solution of lithium bis(trifluoromethanesulfonyl)imide was uniformly mixed with alkoxyvinylimidazolium bromide monomer. The mixture was then stirred at room temperature for 12-24 hours, the precipitate was filtered, washed repeatedly with deionized water, and dried under vacuum to obtain alkoxyvinylimidazolium bis(trifluoromethanesulfonyl)imide monomer.

[0022] The molar ratio of the alkoxyvinylimidazolium bromide monomer to the lithium bis(trifluoromethanesulfonylimide) salt in aqueous solution is 1:1 to 1.5.

[0023] The alkoxyvinylimidazolium bromide monomer is prepared according to the following steps: N-vinylimidazolium and alkoxy bromide were dissolved in dimethyl sulfoxide and reacted under nitrogen protection at 80-100°C for 24-72 hours with stirring. After cooling to room temperature, ethyl acetate was added to precipitate the product. The crude precipitate was filtered, dissolved in deionized water, extracted three times with ethyl acetate, and then rotary evaporated to obtain a mixture. After vacuum drying, the alkoxyvinylimidazolium bromide monomer was obtained.

[0024] The alkoxy bromide is one of 1-(2-(2-methoxyethoxy)ethyl)bromide, 3-(2-methoxyethoxy)bromopropane, 1-(2-bromoethoxy)-2-ethoxybenzene, and 4-bromo-2-ethoxythiazole; The molar ratio of N-vinylimidazolium to alkoxybromide is 1:1~2.

[0025] The initiator is one of azobisisobutyronitrile, azobisisoheptanenitrile, benzoyl peroxide, ammonium persulfate, and potassium persulfate; The mass ratio of the alkoxyvinylimidazolium bis(trifluoromethanesulfonyl)imide monomer to the initiator is 100:1~5.

[0026] In this invention, alkoxyvinylimidazolium bromide monomers are first prepared by carbon alkylation reaction of different types of alkoxy bromides and N-vinylimidazolium. Then, alkoxyvinylimidazolium bis(trifluoromethanesulfonyl)imide monomers are prepared by ion exchange reaction of lithium bis(trifluoromethanesulfonyl)imide. Finally, the alkoxyvinylimidazolium bis(trifluoromethanesulfonyl)imide monomers are subjected to free radical polymerization to obtain the final alkoxylated polyethyleneimine material. The imidazole groups in the material enhance its mechanical strength, and the grafted alkoxy groups promote the formation of an alternating crystalline and amorphous structure between polymer segments, improving the material's adhesive properties. Simultaneously, the electrostatic interaction between the bis(trifluoromethanesulfonyl)imide anions and the imidazole onions promotes the formation of ion aggregates. After microcracks are generated due to material damage, the original alternating crystalline and amorphous structure is destroyed and a new interface is formed. Subsequently, the electrostatic interaction between different regions drives the exchange between ion aggregates and the rearrangement of polymer chain segments, forming a new polymer amorphous stacking structure and filling the crack gaps, thereby realizing the rapid self-healing function of alkoxylated polyethyleneimine material.

[0027] A second aspect of the present invention provides a rapidly self-healing alkoxylated polyethyleneimine material.

[0028] A third aspect of the present invention provides the application of a fast-healing alkoxylated polyethyleneimine material in the encapsulation of perovskite solar cells.

[0029] A fourth aspect of the present invention provides a method for encapsulating a perovskite solar cell, comprising the following steps: After heating and melting the fast self-healing alkoxylated polyethyleneimine material as described in claim 7 into a transparent liquid, it is uniformly coated on the surface of the perovskite solar cell and then stacked with the cover glass in sequence to form a stacked structure. The stacked structure is placed in an air environment at 10~60℃ and subjected to a pressure of 20~40 kPa for 10~30 minutes until curing and cross-linking are completed, thus obtaining a fully encapsulated perovskite solar cell device.

[0030] An exemplary approach is the encapsulation of perovskite solar cells using alkoxylated polyethyleneimine materials with rapid self-healing capabilities, see [link to relevant documentation]. Figure 2 As shown, it includes the following steps: Alkoxylated polyethyleneimine material is heated to 100°C and melted into a transparent liquid. It is then uniformly coated onto the surface of the perovskite solar cell and stacked sequentially with cover glass (transparent glass) to form a "cover glass-encapsulation material-cell-conductive glass" structure. The stacked device of the above composite structure is placed in an air environment at 10~60°C and subjected to a pressure of 20~40 kPa for 10~30 minutes. After curing and cross-linking are completed, a fully encapsulated perovskite solar cell device is formed.

[0031] The perovskite solar cell comprises, in sequence, a conductive glass, a hole transport layer, a perovskite thin film, an electron transport layer, and electrodes. The fabrication method of the perovskite solar cell includes: The conductive glass is subjected to surface ultraviolet light irradiation treatment; a hole transport layer is prepared on the conductive glass; a perovskite thin film is prepared on the hole transport layer; an electron transport layer is prepared on the perovskite thin film; and an electrode is prepared on the electron transport layer.

[0032] The hole transport layer comprises nickel oxide and [4-[3,6-dimethyl-9H-carbazole-9-yl]butyl]phosphonic acid; the electron transport layer comprises [6,6]-phenyl C61 butyrate methyl ester and fullerene; the conductive glass is indium tin oxide conductive glass.

[0033] Fabricating a hole transport layer on conductive glass includes: A nickel oxide aqueous solution was dropped onto conductive glass, and then spin-coated and annealed to obtain a nickel oxide thin film. An ethanol solution of [4-[3,6-dimethyl-9H-carbazole-9-yl]butyl]phosphonic acid was spin-coated onto a nickel oxide film and then annealed to obtain a Me-4PACz film, which is the hole transport layer.

[0034] Fabrication of perovskite thin films on hole transport layers includes: A perovskite precursor solution was prepared, and then coated onto a hole transport layer by spin coating. During spin coating, a certain amount of antisolvent was added dropwise, followed by spin coating for 10-20 seconds, and then annealed at 100-120°C for 15-30 minutes to obtain a perovskite film. The perovskite precursor solution was obtained by dissolving cesium iodide, lead bromide, methylamine hydrobromide, methylamine hydrochloride, formamidinium hydroiodide, and lead iodide in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide; the antisolvent was ethyl acetate.

[0035] Fabrication of an electron transport layer on a perovskite thin film includes: [6,6]-phenyl C61 butyrate methyl ester and fullerene were dissolved in chlorobenzene to obtain an electron transport layer precursor solution. An electron transport layer precursor solution was dropped onto a perovskite thin film, and then spin-coated and annealed to obtain the electron transport layer.

[0036] Electrodes are fabricated on the electron transport layer, including: Under vacuum conditions, 2,9-dimethyl-4,7-biphenyl-1,10-o-phenanthroline and silver were deposited as electrodes using a thermal evaporation method.

[0037] An exemplary method for fabricating perovskite solar cells includes the following main steps: Immerse the indium tin oxide (ITO) glass in deionized water, add a small amount of cleaning agent, and remove oil stains from the ITO glass surface with a brush. Then, ultrasonically rinse it with deionized water, acetone, and IPA respectively, and finally place it in an ethanol solution for later use. Before use, purge the cleaned ITO glass with a nitrogen gun to promote ethanol evaporation, and then treat the ITO glass surface with a UV-ozone generator for 20 minutes.

[0038] Take 20 mg of nickel oxide (NiO) x Dissolved in 1 mL of deionized water and ultrasonically treated for 30 minutes, uniform NiO was obtained. x Aqueous solution, 50 μL of NiO x NiO is obtained by applying an aqueous solution to the ITO glass, followed by spin coating at 3000 rpm for 30 seconds, and then annealing at 150°C for 20 minutes on a heating stage. x layer.

[0039] 0.5 mg of [4-[3,6-dimethyl-9H-carbazole-9-yl]butyl]phosphonic acid (Me-4PACz) was dissolved in 1 mL of anhydrous ethanol and stirred in the dark for at least 12 hours to obtain a homogeneous Me-4PACz precursor solution. The treated substrate was then transferred to a glove box and subjected to oxidation in NiO. xOn the film, 50 μL of Me-4PACz precursor solution was spin-coated at 3000 rpm for 30 seconds and annealed at 100℃ for 10 minutes to obtain a uniform Me-4PACz film.

[0040] Prepare a perovskite precursor solution with the following components: 0.09 mol / L cesium iodide, 0.11 mol / L lead bromide, 0.03 mol / L methylamine hydrobromide, 0.27 mol / L methylamine hydrochloride, 1.61 mol / L formamidin hydroiodide, and 1.7 mol / L lead iodide dissolved in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide in a volume ratio of 4:1.

[0041] Next, 50 μL of the perovskite precursor solution was spin-coated onto the Me-4PACz film, first at 1000 rpm for 10 seconds, then at 5000 rpm for 40 seconds. Twelve seconds before the 40-second spin-coating at 5000 rpm was completed, 150 μL of the antisolvent ethyl acetate (EA) was rapidly added. The ITO glass was then transferred to a heating platform and annealed at 110 °C for 20 minutes.

[0042] Subsequently, methyl [6,6]-phenyl C61 butyrate (PCBM, 99% purity) and fullerene (C60, 99.5% purity) were dissolved in chlorobenzene at a mass ratio of 4:1 to prepare a solution with a concentration of 25 mg / mL. 1 The electron transport layer precursor solution was stirred at room temperature for at least 12 hours and then filtered for later use. Then, an appropriate amount of the electron transport layer precursor solution was dropped onto the perovskite film, spin-coated at 3000 rpm for 40 seconds, and then transferred to a heating stage at 60°C for annealing for 10 minutes to obtain the electron transport layer.

[0043] Finally, at 2×10 -6 Under vacuum conditions of mbar (effective area of ​​0.1 cm²) 2 The device was fabricated by depositing 5 nm of 2,9-dimethyl-4,7-biphenyl-1,10-o-diazaphenanthroline (BCP) and 120 nm of silver (Ag) using a thermal evaporation method.

[0044] It should be noted that, unless otherwise specified, the experimental methods used in this invention are all conventional methods; and the reagents and materials used, unless otherwise specified, are all commercially available.

[0045] Example A1 Preparation process of alkoxylated polyethyleneimine materials: (1) Synthesis of alkoxyvinylimidazolium bromide monomer: A certain proportion of N-vinylimidazolium and 1-(2-(2-methoxyethoxy)ethyl) bromide (molar ratio 1:1.5) were dissolved in DMSO solvent. The mixture was placed in a three-necked flask and stirred at 90°C for 48 hours under nitrogen protection. After cooling to room temperature, ethyl acetate (EA) solvent was slowly added dropwise to the mixture. The mixture gradually precipitated and the precipitate was separated. The crude precipitate was filtered, dissolved in deionized water, extracted three times with ethyl acetate, and then rotary evaporated to obtain a mixture. The mixture was then dried under vacuum at 60°C for 24 hours to obtain 1-(2-(2-methoxyethoxy)ethyl)-3-vinylimidazolium bromide monomer.

[0046] (2) Synthesis of 1-(2-(2-methoxyethoxy)ethyl)-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide monomer: An aqueous solution of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) was added dropwise to 1-(2-(2-methoxyethoxy)ethyl)-3-vinylimidazolium bromide (the molar ratio of alkoxyvinylimidazolium bromide to LiTFSI was 1:1.2). The mixture was then stirred at room temperature for 12 hours, the precipitate was filtered, washed repeatedly with deionized water, and the mixture was vacuum dried at 65°C for 24 hours to obtain the 1-(2-(2-methoxyethoxy)ethyl)-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide monomer.

[0047] (3) Synthesis of 1-(2-(2-methoxyethoxy)ethyl)-3-vinylimidazolium bis(trifluoromethanesulfonylimide) polymer: The monomer 1-(2-(2-methoxyethoxy)ethyl)-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide was dissolved in DMSO and stirred in a flask. Azobisisobutyronitrile (AIBN) was added as an initiator (monomer to initiator mass ratio of 100:1). The mixture was subjected to free radical polymerization at 80°C for 12 hours under nitrogen atmosphere. After the mixture was reacted and cooled to room temperature, excess ethyl acetate was added to precipitate the crude polymer. The precipitate was washed repeatedly with ethyl acetate until the washings were clear. The precipitate was then vacuum dried at 65°C for 24 hours to obtain the 1-(2-(2-methoxyethoxy)ethyl)-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide polymer, i.e., alkoxylated polyethyleneimine material. The NMR data of this material are as follows: Figure 1 As shown.

[0048] The remaining specific process parameters of this embodiment are shown in Table 1.

[0049] Examples A2-A5 Examples A2-A5 were carried out using the same method as Example A1, except that the types and amounts of raw materials used were different from those in Example A1. See Table 1 for details.

[0050] Table 1 shows the process parameters for Examples A1-A5.

[0051] The nuclear magnetic resonance data, weight-average molecular weight, initial thermal decomposition temperature, light transmittance, tensile strength, aqueous solution surface contact angle, yellowness index, and other parameters of the alkoxylated polyethyleneimine materials prepared in Examples A1-A5 are shown.

[0052] The method for testing nuclear magnetic resonance data is: high-resolution nuclear magnetic resonance spectrometer.

[0053] The weight-average molecular weight was determined using gel permeation chromatography.

[0054] The initial thermal decomposition temperature is tested using thermogravimetric analysis.

[0055] The method for testing light transmittance is: visible spectrum absorption test technology.

[0056] The test method for tensile strength is: universal testing machine.

[0057] The test method for surface contact angle is: surface contact angle measuring instrument.

[0058] The method for testing the yellowness index is: yellowness index meter.

[0059] The specific data is shown in Table 2.

[0060] Table 2 Performance data of alkoxylated polyethyleneimine materials prepared in Examples A1-A5

[0061] Example B1 Fabrication of perovskite solar cell devices encapsulated with alkoxylated polyethyleneimine material: First, perovskite solar cell devices are fabricated according to the following steps: Immerse the indium tin oxide (ITO) glass in deionized water, add a small amount of cleaning agent, and remove oil stains from the ITO glass surface with a brush. Then, ultrasonically rinse it with deionized water, acetone, and IPA respectively, and finally place it in an ethanol solution for later use. Before use, purge the cleaned ITO glass with a nitrogen gun to promote ethanol evaporation, and then treat the ITO glass surface with a UV-ozone generator for 20 minutes.

[0062] Take 20 mg of nickel oxide (NiO) xDissolved in 1 mL of deionized water and ultrasonically treated for 30 minutes, uniform NiO was obtained. x Aqueous solution, 50 μL of NiO x NiO is obtained by applying an aqueous solution to the ITO glass, followed by spin coating at 3000 rpm for 30 seconds, and then annealing at 150°C for 20 minutes on a heating stage. x layer.

[0063] 0.5 mg of [4-[3,6-dimethyl-9H-carbazole-9-yl]butyl]phosphonic acid (Me-4PACz) was dissolved in 1 mL of anhydrous ethanol and stirred in the dark for at least 12 hours to obtain a homogeneous Me-4PACz precursor solution. The treated substrate was then transferred to a glove box and subjected to oxidation in NiO. x On the film, 50 μL of Me-4PACz precursor solution was spin-coated at 3000 rpm for 30 seconds and annealed at 100℃ for 10 minutes to obtain a uniform Me-4PACz film.

[0064] Next, a perovskite precursor solution containing the following components was prepared: 0.09 mol / L cesium iodide, 0.11 mol / L lead bromide, 0.03 mol / L methylamine hydrobromide, 0.27 mol / L methylamine hydrochloride, 1.61 mol / L formamidinium hydroiodide, and 1.7 mol / L lead iodide dissolved in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide (800 μL to 200 μL of each solvent). Then, 50 μL of the perovskite precursor solution was spin-coated onto a Me-4PACz film, first at 1000 rpm for 10 seconds, then at 5000 rpm for 40 seconds. Twelve seconds before the spin-coating operation at 5000 rpm for 40 seconds is completed, 150 μL of the antisolvent ethyl acetate (EA) is rapidly added. The ITO glass is then transferred to a heating platform and annealed at 110 °C for 20 minutes to obtain a perovskite film.

[0065] Subsequently, methyl [6,6]-phenyl C61 butyrate (PCBM, 99% purity) and fullerene (C60, 99.5% purity) were dissolved in chlorobenzene at a mass ratio of 4:1 to prepare a solution with a concentration of 25 mg / mL. 1 The electron transport layer precursor solution was stirred at room temperature for at least 12 hours and then filtered for later use. Then, an appropriate amount of the electron transport layer precursor solution was dropped onto the perovskite film, spin-coated at 3000 rpm for 40 seconds, and then transferred to a heating stage at 60°C for annealing for 10 minutes to obtain the electron transport layer.

[0066] Finally, at 2×10 -6Under vacuum conditions of mbar (effective area of ​​0.1 cm²) 2 Perovskite solar devices were obtained by depositing 5 nm of 2,9-dimethyl-4,7-biphenyl-1,10-o-diazaphenanthroline (BCP) and 120 nm of silver (Ag) using a thermal evaporation method.

[0067] The alkoxylated polyethyleneimine material prepared in Examples A1-A5 was heated to 100°C and melted into a transparent liquid. It was then uniformly coated on the surface of the perovskite solar cell and stacked with the cover glass in sequence to form a "cover glass-encapsulation material-cell-conductive glass" structure. The stacked device of the above composite structure was placed in an air environment at 25°C and subjected to a pressure of 30 kPa for 20 minutes. After curing and cross-linking were completed, a fully encapsulated perovskite solar cell device was formed. The remaining specific process parameters of this embodiment are shown in Table 3.

[0068] Examples B2-B7 Examples B2-B7 were carried out using the same method as Example B1, except that the type of alkoxylated polyethyleneimine material and the encapsulation process used were different from those in Example B1, as detailed in Table 2.

[0069] Table 3 shows the process parameters for Examples B1-B7.

[0070] Comparative Example D-B1 The perovskite solar cell in Comparative Example D-B1 was prepared according to the method of Example B1, except that no encapsulation material was used to encapsulate the perovskite solar cell, resulting in an unencapsulated perovskite solar cell, named D-PSC-1.

[0071] Table 4 lists the photoelectric conversion efficiency data, operational stability test data, and surface lead content data of the perovskite solar cells before and after encapsulation, which were obtained by photoelectric conversion efficiency tester, maximum power point (MPPT) stability tester, and inductively coupled plasma mass spectrometry analyzer, respectively.

[0072] Table 4 shows the performance data of the perovskite solar cells before and after encapsulation.

[0073] As shown in Table 4, the alkoxylated polyethyleneimine material with rapid self-healing function provided by the present invention can achieve non-destructive encapsulation of perovskite solar cells. The encapsulated device has high photoelectric conversion efficiency and excellent long-term stability. Furthermore, the lead content leaked by the device is significantly reduced after long-term aging, which helps to promote the industrial application of perovskite photovoltaic devices.

[0074] The perovskite solar cell (PSC-1) encapsulated with EP-1 alkoxylated polyethyleneimine material in Example B1 achieved a cell efficiency of 25.85%. After aging for 1000 hours at 85% relative humidity, it maintained 98.6% of the initial efficiency. After aging for 1000 hours at 85°C, it maintained 97.8% of the initial efficiency. After aging for 1000 hours at the maximum power point under continuous standard sunlight irradiation, it maintained a photoelectric conversion efficiency of 25.10%, equivalent to 97.1% of the initial efficiency. At the same time, after aging for 1000 hours, the lead content on the cell surface was only 0.09 ppm.

[0075] The unencapsulated perovskite solar cell (D-PSC-1) retained only 16.5% of its initial efficiency after aging at 85% relative humidity for 1000 hours, only 14.2% after aging at 85°C for 1000 hours, and only 13.8% after operating at its maximum power point under continuous standard sunlight for 1000 hours. Furthermore, the lead content on the cell surface reached as high as 115.72 ppm after 1000 hours of aging. These comparative results demonstrate that the perovskite solar cell encapsulated with alkoxylated polyethyleneimine material exhibits excellent operational stability, while effectively controlling lead levels in the perovskite device, thus avoiding harm to the environment and organisms.

[0076] To illustrate the performance of the alkoxylated polyethyleneimine material with rapid self-healing function provided by the present invention and its encapsulated perovskite solar cell, the accompanying drawings are provided.

[0077] Figure 1 The alkoxylated polyethyleneimine material in Example B1 13 The figure shows the C NMR data, with the chemical shift peaks corresponding to each chemical group.

[0078] Figure 2 A schematic diagram of a perovskite solar cell device encapsulated with alkoxylated polyethyleneimine material. Figure 2 It is known that the encapsulation process of alkoxylated polyethyleneimine material can achieve the coating and protection of perovskite solar cells, inhibit the intrusion of water vapor and oxygen, and improve the operational stability of photovoltaic devices.

[0079] Figure 3 This is a scanning electron microscope image of the surface of the alkoxylated polyethyleneimine material in Example B1 after encapsulation and curing. Figure 3It is known that after cracks appear on the surface of alkoxylated polyethyleneimine material, the microcracks gradually disappear within 6 minutes in an environment of 50~85℃. This indicates that the electrostatic interaction between ions and the chain segment rearrangement effect in alkoxylated polyethyleneimine encapsulation material endow it with rapid self-healing function, which helps to reduce the risk of lead leakage in perovskite devices and improve their operational stability.

[0080] Although embodiments of the present invention have been shown and described above, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a rapidly self-healing alkoxylated polyethyleneimine material, characterized in that, Includes the following steps: The alkoxyvinylimidazolium bis(trifluoromethanesulfonyl)imide monomer was dissolved in DMSO solvent, and then a certain proportion of initiator was added as an initiator. Under nitrogen atmosphere protection, a free radical polymerization reaction was initiated at 70~90℃. After washing with ethyl acetate multiple times, the alkoxylated polyethyleneimine material was obtained.

2. The method for preparing the rapid self-healing alkoxylated polyethyleneimine material according to claim 1, characterized in that, The alkoxyvinylimidazolium bis(trifluoromethanesulfonylimide) monomer is prepared according to the following steps: An aqueous solution of lithium bis(trifluoromethanesulfonyl)imide was uniformly mixed with alkoxyvinylimidazolium bromide monomer. The mixture was then stirred at room temperature for 12-24 hours, the precipitate was filtered, washed repeatedly with deionized water, and dried under vacuum to obtain alkoxyvinylimidazolium bis(trifluoromethanesulfonyl)imide monomer.

3. The method for preparing the rapid self-healing alkoxylated polyethyleneimine material according to claim 2, characterized in that, The molar ratio of the alkoxyvinylimidazolium bromide monomer to the lithium bis(trifluoromethanesulfonylimide) salt in aqueous solution is 1:1 to 1.

5.

4. The method for preparing the rapid self-healing alkoxylated polyethyleneimine material according to claim 2, characterized in that, The alkoxyvinylimidazolium bromide monomer is prepared according to the following steps: N-vinylimidazolium and alkoxy bromide were dissolved in dimethyl sulfoxide and reacted under nitrogen protection at 80-100°C for 24-72 hours with stirring. After cooling to room temperature, ethyl acetate was added to precipitate the product. The crude precipitate was filtered, dissolved in deionized water, extracted three times with ethyl acetate, and then rotary evaporated to obtain a mixture. After vacuum drying, the alkoxyvinylimidazolium bromide monomer was obtained.

5. The method for preparing the rapid self-healing alkoxylated polyethyleneimine material according to claim 4, characterized in that, The alkoxy bromide is one of 1-(2-(2-methoxyethoxy)ethyl)bromide, 3-(2-methoxyethoxy)bromopropane, 1-(2-bromoethoxy)-2-ethoxybenzene, and 4-bromo-2-ethoxythiazole; The molar ratio of N-vinylimidazolium to alkoxybromide is 1:1~2.

6. The method for preparing the rapid self-healing alkoxylated polyethyleneimine material according to claim 1, characterized in that, The initiator is one of azobisisobutyronitrile, azobisisoheptanenitrile, benzoyl peroxide, ammonium persulfate, and potassium persulfate; The mass ratio of the alkoxyvinylimidazolium bis(trifluoromethanesulfonyl)imide monomer to the initiator is 100:1~5.

7. A rapidly self-healing alkoxylated polyethyleneimine material prepared by the method of any one of claims 1 to 6.

8. The application of the fast self-healing alkoxylated polyethyleneimine material of claim 7 in the encapsulation of perovskite solar cells.

9. A method for encapsulating a perovskite solar cell, characterized in that, Includes the following steps: After heating and melting the fast self-healing alkoxylated polyethyleneimine material as described in claim 7 into a transparent liquid, it is uniformly coated on the surface of the perovskite solar cell and then stacked with the cover glass in sequence to form a stacked structure. The stacked structure is placed in an air environment at 10~60℃ and subjected to a pressure of 20~40 kPa for 10~30 minutes until curing and cross-linking are completed, thus obtaining a fully encapsulated perovskite solar cell device.

10. The method for encapsulating perovskite solar cells according to claim 9, characterized in that, The perovskite solar cell comprises conductive glass, a hole transport layer, a perovskite thin film, an electron transport layer, and electrodes stacked sequentially.

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