Ionic gel thin film material for efficiently fixing lead as well as preparation method and application of ionic gel thin film material

Abstract

The invention discloses an efficient lead-fixing ionic gel thin film material and a preparation method and application thereof, and relates to the technical field of photovoltaic.The preparation method comprises the following steps that organic molecular monomers, ionic liquid, a cross-linking agent and a photoinitiator are evenly mixed, and a precursor solution is formed; wherein the organic molecular monomer at least contains one unsaturated double bond for polymerization, and simultaneously has at least one of oxygen, sulfur and phosphorus functional groups capable of being coordinated with lead ions; the ionic liquid does not generate adverse reaction with the perovskite thin film, and anions of the ionic liquid have strong binding force to lead ions; then standing to complete the degassing process until no visible bubbles exist in the solution; under the condition of ultraviolet irradiation, the precursor solution is subjected to free radical cross-linking reaction, and the ionic gel film is formed after curing and cross-linking. The ionic gel thin film material can be integrated in a perovskite photovoltaic module packaging structure, a protective layer with an active lead fixing function is constructed, lead ions are effectively inhibited from being dissolved out, and the environmental safety of a perovskite photovoltaic device is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photovoltaic technology, in particular to a high-efficiency lead immobilization ion gel thin film material and its preparation method and application. BACKGROUND

[0002] The high-efficiency and stable operation of perovskite photovoltaic devices still relies on the key role of lead components, but its commercialization process faces a core challenge: the toxicity risk of lead in water-soluble halide perovskite. When the module is damaged under harsh weather conditions, rainwater may cause toxic lead ions in the perovskite layer to leach out, thereby polluting the soil and groundwater system.

[0003] The current technology has significant limitations mainly in the following aspects: the adsorption capacity of traditional ion exchange resin for lead ions is limited and the kinetics is slow, which restricts the commercialization process of perovskite batteries; metal organic framework materials and two-dimensional layered materials have high specific surface area, but their selectivity is insufficient in complex environments containing bromine / iodine ions. The mainstream polymer packaging materials (ethylene-vinyl acetate EVA, ethylene-octene copolymer POE) can only provide physical barrier protection and lack the ability to actively adsorb leaked lead ions, posing a risk of lead leakage under extreme weather conditions, especially physical impact, which can easily cause damage to the module structure, thereby causing lead leakage and posing a safety hazard, hindering its commercial application.

[0004] Therefore, developing a new type of packaging material that is compatible with existing processes and can actively and efficiently capture lead ions when the module is damaged is a key requirement for promoting the commercial application of perovskite photovoltaic technology. SUMMARY

[0005] To overcome the shortcomings of the prior art, the present application solves the technical problem of developing a new type of packaging material that is compatible with existing processes and can actively and efficiently capture lead ions when the module is damaged, which is a key requirement for promoting the commercial application of perovskite photovoltaic technology.

[0006] In order to achieve the above technical purpose, the present application mainly adopts the following technical solutions: The present application discloses a preparation method of an ion gel thin film material for efficient lead immobilization, comprising the following steps: Step one, uniformly mix organic monomer, ionic liquid, crosslinking agent and photoinitiator to form a precursor solution; The organic monomer contains at least one unsaturated double bond for polymerization and simultaneously has oxygen and / or sulfur and / or phosphorus functional groups with strong coordination ability for lead ions; The ionic liquid does not react adversely with the perovskite thin film, and its anion has strong binding force for lead ions; Step two, inject the precursor solution obtained in step one into a silica gel mold, and let it stand until the bubbles in the precursor solution disappear; Step three, under the condition of ultraviolet irradiation, the precursor solution occurs radical crosslinking reaction, and the ion gel thin film is formed after solidification and crosslinking.

[0007] In the preferred embodiment of the present application, in step one, the organic molecule monomer is an acrylate monomer, and the ionic liquid is one or more of the following: imidazole, quaternary ammonium, pyridine, phosphine-based sulfate, phosphine-based phosphate.

[0008] Specifically, the acrylate monomer is selected from one or more of the following: 2-methyl-2-acrylic acid-2-hydroxyethyl ester phosphate, 2-ethyl sulfonate methacrylate, 2-hydroxyethyl methacrylate; and the ionic liquid is selected from one or more of the following: methyltributylphosphonium methyl sulfate, methyltributylphosphonium dimethyl phosphate, 1-ethyl-3-methylimidazolium dimethyl phosphate, 1-ethyl-3-methylimidazolium ethyl sulfate.

[0009] In the preferred embodiment of the present application, in step one, the crosslinking agent is polyethylene glycol diacrylate, and the photoinitiator is 2,2-diethoxyacetophenone.

[0010] Preferably, the concentration of the organic molecule monomer is 0.1-10.0 M, the amount of the crosslinking agent is 0.1-10.0 mol% of the monomer, and the amount of the photoinitiator is 0.01-1.0 mol% of the monomer. More preferably, the concentration of the organic molecule monomer is 4.5 M, the amount of the crosslinking agent is 0.2 mol% of the monomer, and the amount of the photoinitiator is 0.125 mol% of the monomer.

[0011] In the preferred embodiment of the present application, in step three, the polymerization and curing conditions are as follows: the 365 nm ultraviolet light irradiation is not less than 10 minutes at 100 mW / cm².

[0012] The present application also discloses a high-efficiency lead-fixed ion gel thin film material prepared by the above method.

[0013] The present application also discloses an application of the ion gel thin film material as described above in the preparation of a perovskite photovoltaic module packaging structure.

[0014] The present application also discloses a perovskite photovoltaic module packaging structure, which comprises, from top to bottom, an anti-reflection layer, an ion gel layer 1, an ITO glass layer, a hole transport layer, a perovskite active layer, an electron transport layer, an electrode layer, a barrier layer, an ion gel layer 2, and a glass packaging layer; the ion gel layer 1 and the ion gel layer 2 are high-efficiency lead-fixed ion gel thin film materials prepared by the above method.

[0015] In the preferred embodiment of the present application, the ion gel layer 1 has a thickness of 300 microns; the electron transport layer is made of C 60 and BCP, with a thickness of 20 nanometers; the electrode layer is made of copper, with a thickness of 100 nanometers; the barrier layer is made of ethylene-octene copolymer, with a thickness of 100 microns or more; the ion gel layer 2 has a thickness of 500 microns, and the full perovskite photovoltaic module has an aperture area of 10.4 cm 2 .

[0016] Compared with the prior art, the present application has the following beneficial effects: 1. Technical advantages: (1) High efficiency and permanent lead fixation: Traditional adsorbent materials (such as activated carbon, resin) can only physically adsorb, and there is a risk of secondary leakage after saturation. The mainstream polymer packaging materials (ethylene-vinyl acetate EVA, ethylene-octene copolymer POE) can only provide physical barrier protection and lack the ability to actively adsorb leaked lead ions. The ion gel of the present application forms a strong coordination bond or insoluble salt with lead ions through the designed functional monomers (such as sulfonate, hydroxyl, and phosphate groups), achieving "adsorption-fixation" in one step. This irreversible chemical lead fixation mechanism ensures that lead is permanently locked, fundamentally solving the core pain point of environmental safety.

[0017] 2. Performance indicators

[0018] (1) Adsorption capacity: The adsorption capacity of the ion gel is as high as 1066 mg / g; (2) Adsorption rate: The removal rate of 160 ppm Pb solution is greater than 85% within 15 minutes; the lead pollution concentration of rainwater caused by perovskite component damage can be reduced from 6.97 ppm to 6 ppb within 45 minutes, meeting the United Nations drinking water safety standards; (3) Resistance to physical impact: It can resist physical impact of a 64g steel ball; (4) Module performance: Compatible with water vapor / oxygen barrier materials, does not induce perovskite decomposition, and does not affect the photoelectric conversion efficiency of the component; 3. Production implementation advantages (1) Cheap raw materials: The selected monomers, crosslinking agents, and ion liquids are all commercial products, with stable sources and controllable prices, without special or expensive rare materials.

[0019] (2) Process compatibility: Through an optimized preparation method, the gel can be used as part of the packaging structure (such as replacing part of the edge sealant or integrated into the backside of the backsheet), or applied as a functional coating to critical areas. This integrated design does not significantly change the existing component structure and production process, does not encroach on the active area, has minimal impact on the photoelectric performance of the component, and greatly reduces the acceptance threshold and modification cost of the industry chain.

[0020] (3) Industrial application prospect summary: The application not only provides a new packaging material, but also provides a key pass for the safe commercialization of perovskite photovoltaic technology. Its clear technical advantages, verifiable performance indicators, and seamless production scheme with existing industries make it have great potential to quickly move from the laboratory to the market. It is expected to become the standard configuration of all future high-performance, long-life perovskite photovoltaic modules, and has a very broad market prospect.

[0021] The concept, specific structure and technical effects of the present application will be further described in conjunction with the accompanying drawings to fully understand the purpose, features and effects of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 Preparation process and lead ion absorption mechanism schematic diagram of the ion gel thin film material provided by the present application; Figure 2 Infrared spectrum characteristic diagram of the ion gel thin film material provided by the present application before and after absorbing lead ions; Figure 3 Lead ion adsorption kinetics diagram of the ion gel thin film material provided by the present application at different temperatures; Figure 4 Adsorption isotherm curve diagram of the ion gel thin film material provided by the present application for lead ions; Figure 5 Packaging method structure diagram of the perovskite module of the reference group and the experimental group provided by the present application; wherein a is the reference group, and b is the experimental group; Figure 6 Physical photos of the reference group and the experimental group perovskite module packaging before and after continuous impact of steel balls provided by the present application; wherein a-b are physical photos of the reference group before and after continuous impact of steel balls, respectively, and c-d are physical photos of the experimental group perovskite module packaging before and after continuous impact of steel balls, respectively; Figure 7 Lead ion concentration change diagram of the reference group and the experimental group perovskite module packaging in the water immersion experiment provided by the present application; Figure 8 Voltage-current scanning curve diagram of the narrow band gap, wide band gap and laminated module of the experimental group provided by the present application; Figure 9 Efficiency statistical diagram and long-term light stability diagram of the reference group and the experimental group perovskite module provided by the present application. DETAILED DESCRIPTION

[0023] The technical content of the present application will be more clearly understood and facilitated to be understood through the following reference to the drawings of the specification which introduce a plurality of preferred embodiments of the present application. The present application can be embodied in many different forms of embodiments, and the protection scope of the present application is not limited to the embodiments mentioned herein.

[0024] The present application proposes a high-efficiency lead-fixing ionic gel thin film material and its preparation method and application. The material design has the following characteristics: 1. The selected organic monomer contains at least one unsaturated double bond for polymerization, and at the same time has a functional group (such as oxygen, sulfur, phosphorus group) with strong coordination ability to lead ions. 2. The selected ionic liquid does not react with perovskite film, and its anion also has strong binding force to lead ions. 3. The raw materials (monomers, ionic liquids, etc.) used are low in cost and easy to obtain. 4. The ionic gel formed finally has good optical transparency, mechanical strength and elasticity.

[0025] Based on the above principles, the present application preferably selects a series of acrylate monomers such as 2-methyl-2-acrylic acid-2-hydroxyethyl ester phosphate, 2-ethyl sulfonate methacrylate, 2-hydroxyethyl methacrylate, and methyl tributyl phosphonium methyl sulfate, 1-ethyl-3-methyl imidazole methyl sulfate, pyridine sulfate ionic liquid. The preparation method of such ionic gel thin film material is simple and efficient. The monomer, covalent crosslinking agent, photoinitiator and ionic liquid are mixed into a homogeneous precursor solution at room temperature, and then polymerization is initiated by ultraviolet light to solidify and form. Finally, the ionic gel thin film material is integrated into the packaging structure of the perovskite photovoltaic module to construct an active defense barrier. When the module is accidentally damaged, the material not only maintains physical packaging, but also quickly locks and adsorbs the leaked lead ions with its functional groups, thereby greatly inhibiting the dissolution of lead, making the exudate concentration meet the international drinking water safety standards, and providing reliable protection for the environmental safety and sustainable development of perovskite photovoltaic technology.

[0026] The following will be described through the drawings and specific embodiments.

[0027] Example 1

[0028] A preparation method of a high-efficiency lead-fixing ionic gel thin film material is as follows: The raw materials 2-methyl-2-hydroxyethyl acrylate phosphate, methyltributylphosphonium methyl sulfate (CAS No. 69056-62-8), polyethylene glycol diacrylate, and a photoinitiator 2,2-diethoxyacetophenone are mixed uniformly and bubbles are removed. Among them, the ratio of each component raw material is: 2-methyl-2-hydroxyethyl acrylate phosphate is 4.5 M, the amount of crosslinking agent polyethylene glycol diacrylate is 0.2 mol% of the monomer; the amount of photoinitiator is 0.125 mol% of the monomer. Under an inert atmosphere, irradiate with 100 mW / cm² of 365 nm ultraviolet light for more than 10 minutes, and finally obtain a high-transparency and good-mechanical-strength ionic gel thin film, as shown in Figure 1 .

[0029] Example 2

[0030] The preparation method is basically the same as that of Example 1, except that 2-methyl-2-hydroxyethyl acrylate phosphate is replaced by 2-ethyl sulfonate methacrylate, and the others are the same as Example 1.

[0031] Example 3

[0032] The preparation method is basically the same as that of Example 1, except that 2-methyl-2-hydroxyethyl acrylate phosphate is replaced by 2-hydroxyethyl methacrylate, and the others are the same as Example 1.

[0033] Example 4

[0034] A perovskite photovoltaic module packaging structure, as shown in Figure 5 b, from top to bottom, includes an anti-reflection layer, an ionic gel layer 1, an ITO glass layer, a hole transport layer, a perovskite active layer, an electron transport layer, an electrode layer, a barrier layer, an ionic gel layer 2, and a glass packaging layer; the ionic gel layer 1 and the ionic gel layer 2 are high-efficiency solid-lead ionic gel thin film materials prepared by the above method.

[0035] Among them, the thickness of the ionic gel layer 1 is 300 microns; the electron transport layer is made of C 60 70 and BCP, with a thickness of 20 nanometers; the electrode layer is made of copper, with a thickness of 100 nanometers; the barrier layer is made of ethylene-octene copolymer, with a thickness of more than 100 microns; the thickness of the ionic gel layer 2 is 500 microns, and the aperture area of the full perovskite photovoltaic module is 10.4 cm 2 .

[0036] The packaging method used is to place the in-situ polymerized transparent ionic gel material outside the ITO glass incident end, and place the ionic gel inside the packaging glass.

[0037] The structure design realizes the two problems of physical reliability and environmental safety of the device under the premise of not sacrificing any photoelectric conversion efficiency. The packaging layer can effectively buffer the mechanical stress caused by hail, snow and the like, and reduce the physical damage degree of the battery. Even in the extreme case of packaging failure, the inherent super-high lead adsorption capacity can immediately play a role, and build a double synergistic protection mechanism of impact resistance and lead leakage prevention.

[0038] Comparative Example 1

[0039] A traditional glass packaging module packaging structure, as shown in Figure 5 Fig. a, from top to bottom includes an anti-reflection layer, an ITO glass layer, a perovskite module layer and a glass packaging layer.

[0040] Test Example 1: Investigation of the change in infrared spectral characteristic peaks of the ion gel thin film material prepared in Example 1 of the present application before and after adsorbing lead ions

[0041] As shown in Figure 2 , before the ion gel thin film material prepared in Example 1 of the present application adsorbs lead ions, the characteristic peaks of P=O bond on the polymer branched chain in the ion gel and S=O bond in the ionic liquid appear at 1159, 976 cm -1 , respectively, and after adsorbing lead ions, the characteristic peaks of both are red-shifted, indicating that the phosphate group on the polymer branched chain and the sulfate anion in the ionic liquid have interacted with lead ions.

[0042] Test Example 2: Investigation of the lead ion adsorption kinetics of the ion gel thin film material prepared in Example 1 of the present application at different temperatures

[0043] As shown in Figure 3 , under the conditions of 20, 40 and 60℃, the adsorption of lead ions by the ion gel thin film material prepared in Example 1 of the present application reaches equilibrium state in about 45 minutes, and the adsorption kinetics of lead is more consistent with the characteristics of pseudo-second-order kinetics, i.e. it belongs to a chemical adsorption process.

[0044] Test Example 3: Investigation of the adsorption isotherm type of lead ions by the ion gel thin film material prepared in Example 1 of the present application

[0045] As shown in Figure 4 , the adsorption process of lead ions by the ion gel conforms to the Langmuir adsorption isotherm model, and through fitting, it can be obtained that the maximum saturated adsorption capacity of lead ions by the ion gel at 20℃ is 1066 mg·g -1 , indicating that the ion gel has a super-high lead ion adsorption capacity.

[0046] Test Example 4: Investigate the ball impact test results of the encapsulated perovskite module prepared by the comparative example 1 (as a reference group) and the example 4 (as an experimental group) provided by the present application

[0047] The ball impact test was carried out according to the GB / T 29551-2023 standard, and the results are shown in Figure 6 The ionic gel encapsulation layer in the experimental group remained intact after 64 g steel ball continuous impact, and its impact resistance was better than that of the comparative example 1.

[0048] Test Example 5: Investigate the lead ion concentration changes of the reference group and the experimental group encapsulated perovskite module after breaking and water immersion experiment

[0049] As shown in Figure 7 In pure deionized water, pH = 4.2, pH = 7 or pH = 4.2 and containing 10 ppm Ca 2+ , Mg 2+ environment, compared with the control group, the experimental group can effectively fix lead ions in such complex environment, and the lead leaching concentration is significantly lower than that of the reference group, which can almost completely encapsulate the lead ions in the perovskite module, and the encapsulation rate is higher than 99.8%, which proves the excellent adaptability and reliability of the encapsulation of the present application. It is proved that the ionic gel of the experimental group can effectively inhibit the lead leakage of the perovskite module.

[0050] Test Example 6: Investigate the voltage-current scan curves of the narrow band gap, wide band gap and laminated module of the experimental group provided by the present application

[0051] Under the irradiation of AM 1.5G standard solar simulator, the photoelectric performance of the laminated battery was tested according to the IEC 60904-1 standard, and the obtained photoelectric conversion efficiency, open circuit voltage, short circuit current density and fill factor are shown in Figure 8 The open circuit voltage, short circuit current, fill factor and photoelectric conversion efficiency results are shown in the following table 1.

[0052]

[0053] Test Example 7: Investigate the efficiency histogram and long-term light stability of the reference group and the experimental group perovskite module provided by the present application

[0054] According to the IEC 63209-1 standard, the light stability of the battery was evaluated by the maximum power point tracking (MPPT) method. As shown in Figure 9 The efficiency of the reference group and the experimental group was 20.8 ± 0.6% and 21.0 ± 0.6%, respectively. As shown in Figure 9As shown in Table B, in the subsequent 500-hour long-term light stability test, the efficiency retention rates of the reference group and the experimental group are 82.8% and 83.2% respectively, indicating that the ionic gel material as the encapsulation layer does not affect the photovoltaic efficiency and stability of the photovoltaic device. It is shown that the laminated module packaged by the ionic gel of the application exhibits excellent long-term running stability while maintaining high photoelectric conversion efficiency.

[0055] The preferred embodiments of the application are described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and changes without creative work based on the concept of the application. Therefore, any technical solutions obtained by logical analysis, reasoning or limited experiments based on the prior art according to the concept of the application should be within the protection scope determined by the claims.

Claims

1. A method for preparing an efficient lead immobilization ionic gel thin film material, characterized in that, It comprises the following steps: Step one, uniformly mix organic molecule monomer, ionic liquid, crosslinking agent and photoinitiator to form precursor solution; The organic molecule monomer contains at least one unsaturated double bond for polymerization, and simultaneously has oxygen and / or sulfur and / or phosphorus functional groups with strong coordination ability to lead ions; The ionic liquid does not react with perovskite film, and its anion has strong binding force to lead ions; Step two, inject the precursor solution obtained in step one into a silica gel mold, and stand until the bubbles in the precursor solution disappear; Step three, under the condition of ultraviolet light irradiation, the precursor solution undergoes free radical crosslinking reaction, and after curing and crosslinking, ionic gel film is formed.

2. The method of claim 1, wherein the method further comprises the step of: In step one, the organic molecule monomer is an acrylate monomer, and the ionic liquid is one or more combinations of imidazole, quaternary ammonium, pyridine, phosphine sulfate, and phosphine phosphate.

3. The method of claim 2, wherein the method further comprises the step of: The acrylate monomer is one or more combinations of 2-methyl-2-acrylic acid-2-hydroxyethyl ester phosphate, 2-ethyl sulfonate methacrylate, and 2-hydroxyethyl methacrylate; and the ionic liquid is one or more combinations of methyltributylphosphonium methyl sulfate, methyltributylphosphonium dimethyl phosphate, 1-ethyl-3-methylimidazole dimethyl phosphate, and 1-ethyl-3-methylimidazole ethyl sulfate.

4. The process for the preparation of high efficient lead immobilized ionogel thin film material as claimed in claim 1 wherein, In step one, the crosslinking agent is polyethylene glycol diacrylate, and the photoinitiator is 2,2-diethoxyacetophenone.

5. The process for the preparation of high efficient lead immobilized ionogel thin film material as claimed in claim 4 wherein, The concentration of the organic molecule monomer is 0.1-10.0 M, the amount of the crosslinking agent is 0.1-10.0 mol% of the monomer, and the amount of the photoinitiator is 0.01-1.0 mol% of the monomer.

6. The process for the preparation of high efficient lead immobilized ionogel thin film material as claimed in claim 1 wherein, In step three, the polymerization and curing conditions are as follows: irradiation with 365 nm ultraviolet light at 100 mW / cm² for not less than 10 minutes.

7. The high-efficiency lead-fixing ionic gel film material prepared by the method of any one of claims 1-6.

8. The use of the ionic gel film material of claim 7 in the preparation of a perovskite photovoltaic module packaging structure.

9. A perovskite photovoltaic module encapsulation structure, characterized by, From top to bottom, it comprises an anti-reflection layer, an ionic gel layer 1, an ITO glass layer, a hole transport layer, a perovskite active layer, an electron transport layer, an electrode layer, a barrier layer, an ionic gel layer 2, and a glass packaging layer; the ionic gel layer 1 and the ionic gel layer 2 are high-efficiency lead-fixing ionic gel film materials prepared by the method of any one of claims 1-6.

10. The perovskite photovoltaic module encapsulation structure of claim 9, wherein, The ion gel layer 1 has a thickness of 300 microns; the electron transport layer has a material of C 60 and BCP, a thickness of 20 nanometers; the electrode layer has a material of copper, a thickness of 100 nanometers; the barrier layer has a material of ethylene-octene copolymer, a thickness of 100 microns or more; the ion gel layer 2 has a thickness of 500 microns, and the full perovskite photovoltaic module has an aperture area of 10.4 cm 2 .

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