Anti-reflection self-cleaning coated photovoltaic glass and preparation method thereof

Abstract

The invention belongs to the field of functional photovoltaic glass, and particularly relates to antireflection self-cleaning coated photovoltaic glass and a preparation method thereof.The preparation method comprises the steps that cleaning and surface activation pretreatment are conducted on an original photovoltaic glass sheet; then preparing a coating solution by a sol-gel method, hydrolyzing a silane coupling agent under an acidic condition, and then mixing and aging the hydrolyzed silane coupling agent with a solution of dispersed mesoporous silica nanoparticles, silica nanoparticles, perfluoropolyether polyhedral oligomeric silsesquioxane and polydimethylsiloxane grafted trifluoropropyl silsesquioxane; and finally, forming a composite functional coating on the surface of the glass through dip coating and stepped heat treatment. The coated glass prepared by the method has excellent anti-reflection and self-cleaning performance, the visible light transmittance of the coated glass is remarkably improved, the water contact angle is large, the coated glass is hydrophobic and oleophobic, environmental abrasion and erosion can be effectively resisted, and the coated glass can be widely applied to photovoltaic modules to improve the power generation efficiency and reduce the maintenance cost.

Description

Technical Field

[0001] This invention belongs to the field of functionalized photovoltaic glass technology, specifically relating to an anti-reflective self-cleaning coated photovoltaic glass and its preparation method. Background Technology

[0002] As a key encapsulation material for photovoltaic modules, the optical performance of photovoltaic glass directly affects the power generation efficiency of the entire system. With the rapid development of building-integrated photovoltaics (BIPV) technology, photovoltaic glass is no longer just a power generation element, but has become an important component of building envelope and facade decoration. This places higher demands on the optical performance, aesthetics, and long-term maintenance of photovoltaic glass. Untreated glass surfaces suffer from light reflection loss due to the difference in refractive index with air, which significantly reduces the photovoltaic cells' ability to capture light energy. Furthermore, photovoltaic modules, exposed to the outdoor environment for extended periods, inevitably accumulate dust, pollutants, bird droppings, etc., creating a shading effect and potentially fostering mold and algae growth. On building facades, this pollution not only affects power generation efficiency but also severely damages the building's appearance. Cleaning and maintaining photovoltaic curtain walls on high-rise buildings is particularly difficult and costly. Numerous studies and practices have shown that severe surface contamination can lead to a decrease in the output power of photovoltaic modules, especially in arid regions with high dust levels. This not only results in economic losses in power generation but also increases the labor and water costs associated with frequent cleaning and maintenance. Therefore, developing a high-performance photovoltaic glass that can simultaneously reduce light reflection and has self-cleaning capabilities is of paramount importance for improving the power generation efficiency of photovoltaic power plants throughout their entire lifecycle and reducing operation and maintenance costs.

[0003] Currently, the main technological approaches to improving the performance of photovoltaic glass revolve around anti-reflection and self-cleaning functions. In terms of anti-reflection, the most mature and widely used method is porous silica coatings prepared using the sol-gel process. This technology reduces the effective refractive index of the coating by constructing nanoscale pores, thereby creating a refractive index gradient between the glass and air and effectively suppressing Fresnel reflection. However, these porous structures are inherently hydrophilic and have high surface energy, easily adsorbing oil and polar pollutants from the environment and retaining moisture. Especially in built environments, facing complex components such as oily pollutants and vehicle exhaust residues in urban air, the pollution problems of traditional porous structures are more significant. Regarding self-cleaning, mainstream technologies include superhydrophobic coatings and liquid film slip surfaces. Superhydrophobic coatings mimic the lotus leaf effect, but their micro-nano rough structure lacks mechanical durability under long-term exposure to outdoor wind, sand, raindrops, and ultraviolet radiation, and their hydrophobic function is prone to failure. Liquid film slip surfaces, on the other hand, face problems such as lubricant loss, complex preparation processes, and the potential introduction of additional light scattering or absorption in optical applications. Existing technologies attempt to integrate these two functions, but often face the dilemma of complicated process steps or difficulty in achieving both performance. For example, the double-layer structure of first preparing the anti-reflection layer and then coating the self-cleaning layer has the risk of poor interlayer adhesion and increased interface reflection.

[0004] In summary, existing technologies present a significant contradiction: the porous structure employed to achieve efficient anti-reflection is detrimental to achieving stable and durable self-cleaning functionality; conversely, conventional self-cleaning surface designs often struggle to balance extremely high light transmittance and mechanical durability. This contradiction is even more pronounced in architectural applications, requiring photovoltaic glass to not only possess excellent power generation performance but also to consider architectural aesthetics, safety, and low maintenance. Many reported integrated solutions require multiple coatings or complex post-processing steps, hindering large-scale industrial production and cost control. Therefore, there is an urgent need in this field for an innovative technological solution that can construct a composite functional coating on the photovoltaic glass surface through a simplified process, particularly a single coating, possessing high light transmittance, excellent and durable self-cleaning properties, and good environmental stability. This coating needs to be designed from the fundamental aspects of its material system, cleverly unifying the physical structure required for anti-reflection with the chemical properties required for self-cleaning, thereby fundamentally overcoming the bottleneck of functional constraints in current technologies. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide an anti-reflective self-cleaning coated photovoltaic glass and its preparation method.

[0006] In a first aspect, the present invention provides a method for preparing anti-reflective self-cleaning coated photovoltaic glass, comprising the steps of: S1. The photovoltaic glass substrate is ultrasonically cleaned with deionized water and neutral detergent, then rinsed with ethanol, dried with nitrogen, and finally treated with ultraviolet ozone to obtain pretreated photovoltaic glass; γ-glycidyl etheroxypropyltrimethoxysilane is added to ethanol and deionized water, and the pH is adjusted to 3-4 under stirring. Hydrolysis reaction is carried out at 44-46℃ to obtain hydrolyzed silane solution; mesoporous silica nanoparticles and silica nanoparticles are added to ethanol and ultrasonically dispersed to obtain mixture A; perfluoropolyether-based polyhedral oligomeric silsesquioxane and polydimethylsiloxane grafted with trifluoropropylsilsesquioxane are added to ethanol and stirred until completely dissolved to obtain mixture B; mixture A and mixture B are added sequentially to the hydrolyzed silane solution and stirred at 44-46℃ to obtain coating solution; S2. Immerse the pretreated photovoltaic glass vertically into the coating solution, let it stand, and then pull it out of the liquid surface to obtain the coated glass. Send the coated glass into a heat treatment furnace, first dry it at 78-82℃, then pre-cur it at 145-155℃, and finally heat treat it at 275-285℃.

[0007] In this invention, the film-forming mechanism of the antireflective self-cleaning coated photovoltaic glass encompasses the sol-gel conversion and interface anchoring processes. Mesoporous silica nanoparticles and solid silica nanoparticles in the coating solution constitute the antireflective framework: the mesoporous structure, by controlling the pore size and distribution, generates a gradient refractive index effect, causing destructive interference of incident light at the air-film interface, significantly reducing reflection loss. The silane coupling agent, after hydrolysis, generates silanol, which condenses with hydroxyl groups on the nanoparticle surface under acidic conditions, forming a network structure bridged by siloxane bonds. Perfluoropolyether-based polyhedral oligomeric silsesquioxane and polydimethylsiloxane grafted with trifluoropropylsilsesquioxane serve as functional components, migrating to the film surface during heat treatment: the perfluoro segments are oriented to form a low surface energy top layer, while the polydimethylsiloxane chains fill the pores to enhance density. The pre-curing stage promotes solvent evaporation and initial cross-linking, while high-temperature heat treatment ultimately completes the siloxane network condensation, achieving a strong bond between the film and the glass substrate. During this process, the covalent bonds between functional groups (such as amide bonds and silicon-oxygen bonds) ensure the peel resistance of the film, while the micro-nano composite structure simultaneously achieves the improvement of light transmittance and the dust rolling-off effect, enabling photovoltaic glass to have the functions of anti-reflection, self-cleaning and aging resistance.

[0008] As a preferred embodiment of the present invention, in step S1, the stirring time at 44-46°C is 4-6 hours.

[0009] As a preferred embodiment of the present invention, in step S2, the pre-curing time at 145-155℃ is 15-20 min; and the heat treatment time at 275-285℃ is 1-2 h.

[0010] As a preferred embodiment of the present invention, the method for preparing the perfluoropolyether-based polyhedral oligomeric silsesquioxane includes: A1. Dissolve aminopropyl isobutylsilsesquioxane and perfluoropolyether fluoride in toluene, add triethylamine under ice-water bath cooling and nitrogen protection, heat to room temperature, and stir continuously. A2. After the reaction is complete, the crude product is obtained by vacuum distillation. The crude product is redissolved in dichloromethane and washed successively with deionized water and dilute hydrochloric acid. The organic phases are combined and dried over anhydrous magnesium sulfate. Finally, the product is purified by column chromatography.

[0011] In this invention, the preparation of perfluoropolyether-based polyhedral oligomeric silsesquioxanes involves a one-step amidation condensation reaction. The primary amino group at the terminal of the aminopropyl isobutylsilsesquioxane molecule acts as a strong nucleophile, directly attacking the highly reactive acyl fluoride groups in the perfluoropolyether acyl fluoride molecule. Triethylamine acts as an acid-binding agent, promptly neutralizing the hydrogen fluoride generated in the reaction, driving the reaction towards the product and preventing its corrosion of equipment. This process directly forms stable amide bonds, thereby covalently grafting perfluoropolyether segments onto the cage-like framework of the polyhedral oligomeric silsesquioxane. This design combines the low surface energy characteristics of perfluoropolyethers with the rigid structure of silsesquioxanes. The final product can migrate to the surface in the coating solution, forming a densely packed fluorocarbon layer, endowing the film with excellent waterproof and antifouling properties. The mechanism stems from the high electronegativity of fluorine atoms, which significantly reduces surface energy, while the cage-like framework enhances the thermal stability and mechanical strength of the coating.

[0012] As a preferred embodiment of the present invention, in step A1, the molar ratio of aminopropyl isobutylsilsesquioxane, perfluoropolyether fluoride and triethylamine is 1:(1.05-1.2):(1.10-1.30); and the stirring time is 6-8 hours.

[0013] As a preferred embodiment of the present invention, in step A2, the concentration of the dilute hydrochloric acid is 0.1-0.5 mol / L.

[0014] As a preferred embodiment of the present invention, the method for preparing the polydimethylsiloxane grafted with trifluoropropylsilsesquioxane includes: B1. Mix monohydroxy-terminated polydimethylsiloxane with trifluoropropanetrimethoxysilane, add toluene and dibutyltin dilaurate, and reflux at 105-115℃ to obtain the reaction mixture. B2. Cool the reaction mixture to 68-72℃, add methyltrimethoxysilane and tetraisopropyl titanate, continue the reaction to obtain the reaction mixture, cool the reaction mixture to room temperature, and obtain a viscous liquid by rotary evaporation. Then dissolve the viscous liquid in tetrahydrofuran and add it dropwise to methanol to precipitate. Filter to collect the precipitate and dry the precipitate in a vacuum oven at 58-62℃.

[0015] In this invention, the synthesis of polydimethylsiloxane grafted with trifluoropropylsilsesquioxane is based on silanol condensation and hydrosilylation reactions. Under the action of a catalyst, the terminal hydroxyl groups of the monohydroxyl-terminated polydimethylsiloxane undergo a de-alcoholization reaction with the methoxy groups of trifluoropropanetrimethoxysilane, forming a siloxane-bonded prepolymer. In this step, a tin-based catalyst accelerates the hydrolysis and condensation of silanes, ensuring effective grafting of the flexible polydimethylsiloxane chains with the fluorinated silanes. Subsequently, methyltrimethoxysilane and titanate catalysts are added, and a three-dimensional network structure is constructed through further condensation: silanols are hydrolyzed to generate silanols, and dehydration occurs between silanols to form a cross-linked silsesquioxane framework. Polydimethylsiloxane segments act as flexible spacers, interspersed within the rigid silsesquioxane network, relieving internal stress and improving coating toughness. The introduction of trifluoropropyl groups enhances intermolecular hydrophobic interactions, resulting in a micro / nano-hierarchical rough structure in the cured film, synergistically achieving a superhydrophobic effect with the perfluorinated components. This design balances the hardness and elasticity of the film through an organic-inorganic hybrid strategy, effectively resisting cracking caused by thermal expansion and contraction.

[0016] As a preferred embodiment of the present invention, in step B1, the molar ratio of monohydroxy-terminated polydimethylsiloxane, trifluoropropanetrimethoxysilane and dibutyltin dilaurate is 1:(2.5-3.5):(0.01-0.03).

[0017] As a preferred embodiment of the present invention, in step B2, the reaction continues for 4-6 hours.

[0018] In a second aspect, the present invention provides an anti-reflective self-cleaning coated photovoltaic glass prepared by the method described above, comprising the following raw materials in parts by weight: 10-30 parts of mesoporous silica nanoparticles; 5-15 parts of silica nanoparticles; 1-5 parts of perfluoropolyether-based polyhedral oligomeric silsesquioxane; 2-8 parts of polydimethylsiloxane grafted with trifluoropropylsilsesquioxane; 0.5-3 parts of γ-glycidyl etheroxypropyltrimethoxysilane; 50-80 parts of ethanol; and 1-5 parts of deionized water.

[0019] Compared with the prior art, the present invention has the following beneficial effects: (1) The core technical effect of this invention lies in significantly improving the optical performance of photovoltaic glass. By constructing a nanoporous structure with mesoporous silica nanoparticles and silica nanoparticles as the framework on the glass surface, an effective anti-reflection function is achieved. This structure can utilize the gradient refractive index effect of light to cause destructive interference of reflected light at the air-glass interface, significantly improving the effective transmittance of sunlight. The increase in transmittance directly translates into increased absorption of light energy by the solar cell, thereby improving the photoelectric conversion efficiency of the photovoltaic module. It is worth noting that the film layer achieves the gradient refractive index effect through the mesoporous structure. This structure helps to maintain low reflectance over a wider spectral range and a larger incident angle, i.e., it has good "all-angle anti-reflection" performance, which is particularly important for photovoltaic application scenarios where the illumination angle changes at different times of the day. The combination of high transmittance and effective self-cleaning ability ensures that the photovoltaic module can maintain high power generation output throughout its entire life cycle, providing key material support for achieving "cost reduction and efficiency improvement" in photovoltaic power generation.

[0020] (2) This invention achieves an organic unity of self-cleaning function and anti-reflective performance, and endows the film with excellent surface protection properties through unique molecular design. The perfluoropolyether-based polyhedral oligomeric silsesquioxane and polydimethylsiloxane grafted trifluoropropylsilsesquioxane in the film are the key functional components. The perfluoropolyether segments have extremely low surface energy, which can form a stable fluorocarbon enrichment layer on the film surface, giving the coating superhydrophobic properties. This makes water droplets have a high contact angle and a small roll-off angle on the surface, and rainwater can easily roll off and carry away the dust particles attached to it, thereby achieving a self-cleaning effect. The introduction of polydimethylsiloxane segments significantly enhances the flexibility and cohesion of the film, enabling it to better absorb and release strain caused by thermal expansion and contraction or slight mechanical stress, preventing the coating from cracking or peeling. This combination of rigidity and flexibility in structural design allows the membrane to not only effectively resist dust adsorption, reduce the "hot spot effect" and power generation attenuation caused by dirt blockage, and lower the cost and frequency of manual cleaning, but also its low surface energy characteristics make it resistant to common pollutants such as oil and bird droppings, further enhancing its applicability in complex outdoor environments.

[0021] (3) The coated glass prepared by this invention exhibits excellent mechanical strength and long-term environmental durability, ensuring its reliability in practical applications. The multi-stage heat treatment process is crucial, promoting the hydrolysis and condensation reaction of the silane coupling agent and forming a strong covalent bond network of silicon-oxygen bonds between nanoparticles and between the film layer and the glass substrate. This strong chemical bonding endows the film layer with extremely high adhesion and hardness, enabling it to pass rigorous adhesion tests and possess high pencil hardness, demonstrating excellent scratch resistance and resistance to wind and sand abrasion. Furthermore, the organofluorine-silicon component in the film layer has excellent chemical stability and UV aging resistance, effectively resisting the erosion of harsh conditions such as acid rain, salt spray, and long-term UV exposure in outdoor environments. In summary, the photovoltaic glass successfully prepared by this invention not only boasts superior instantaneous performance but also possesses the potential for long-term stable service in harsh environments, demonstrating significant comprehensive technical effects. Detailed Implementation

[0022] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0023] The sources of some components in the examples and comparative examples are as follows: The mesoporous silica nanoparticles were purchased from Zhejiang Jinkun Xili New Material Technology Co., Ltd.

[0024] The silica nanoparticles were purchased from Guangzhou Jibisheng Technology Industry Co., Ltd.

[0025] The perfluoropolyether fluoride was purchased from Zhonghao Fluorochemical Materials Co., Ltd.

[0026] The xylene was purchased from China Petroleum & Chemical Corporation (Sinopec).

[0027] The triethylamine was purchased from Zhejiang Xinhua Chemical Co., Ltd.

[0028] The aminopropyl isobutylsilsesquioxane was purchased from Shanghai Myriel Biochemical Technology Co., Ltd.

[0029] The monohydroxy-terminated polydimethylsiloxane was purchased from Zhejiang Xin'an Chemical Group Co., Ltd.

[0030] The trifluoropropanetrimethoxysilane was purchased from Guangzhou Yuanda New Materials Co., Ltd.

[0031] The toluene was purchased from China National Petroleum Corporation (CNPC).

[0032] The dibutyltin dilaurate was purchased from Beijing Dicowan Technology Co., Ltd.

[0033] The methyltrimethoxysilane was purchased from Jingzhou Jiangrun Chemical Co., Ltd.

[0034] The tetraisopropyl titanate was purchased from Panzhihua Iron & Steel Group Titanium Industry Co., Ltd.

[0035] Example 1

[0036] This embodiment provides a method for preparing anti-reflective self-cleaning coated photovoltaic glass, the steps of which include: Preparation of perfluoropolyether-based polyhedral oligomeric silsesquioxanes: 10.0 g of aminopropyl isobutyl silsesquioxane and 13.5 g of perfluoropolyether acyl fluoride were dissolved in 50.0 g of toluene. Under ice-water bath cooling and nitrogen protection, 3.8 g of triethylamine was slowly added. The reaction system was then allowed to return to room temperature and stirred continuously for 7.0 h. After the reaction was completed, most of the solvent was removed by vacuum distillation to obtain the crude product. The crude product was redissolved in 80.0 mL of dichloromethane and washed successively with 50.0 mL of deionized water and 50.0 mL of 0.3 mol / L dilute hydrochloric acid. The organic phases were combined and dried with 5.0 g of anhydrous magnesium sulfate. Finally, the product was purified by silica gel column chromatography to obtain perfluoropolyether-based polyhedral oligomeric silsesquioxanes.

[0037] Preparation of polydimethylsiloxane-grafted trifluoropropylsilsesquioxane: 10.0 g of monohydroxyl-terminated polydimethylsiloxane was mixed with 25.0 g of trifluoropropanetrimethoxysilane, 50.0 g of toluene and 0.2 g of dibutyltin dilaurate were added, and the mixture was refluxed at 110.0 °C for 2.0 h to obtain a reaction mixture. The reaction mixture was cooled to 70.0 °C, and 5.0 g of methyltrimethoxysilane and 0.5 g of tetraisopropyl titanate were added, and the reaction was continued for 5.0 h. After the reaction was completed, the mixture was cooled to 25.0 °C, and the solvent was removed by rotary evaporator to obtain a viscous liquid. The viscous liquid was dissolved in 50.0 g of tetrahydrofuran, and precipitated by adding 200.0 g of methanol dropwise. The precipitate was collected by filtration and dried in a vacuum oven at 60.0 °C for 12.0 h to obtain polydimethylsiloxane-grafted trifluoropropylsilsesquioxane.

[0038] Preparation of antireflective self-cleaning coated photovoltaic glass: A photovoltaic glass substrate (100mm × 100mm × 3mm) was ultrasonically cleaned for 20 minutes with 100.0g deionized water and 5.0g neutral detergent, then rinsed with 50.0g ethanol, dried with nitrogen, and finally treated with ultraviolet ozone for 10 minutes to obtain pretreated photovoltaic glass. 2.0g of γ-glycidyl etheroxypropyltrimethoxysilane was added to 65.0g ethanol and 3.0g deionized water. The mixture was stirred at 300r / min, and the pH was adjusted to 3.5 with dilute hydrochloric acid. The mixture was then subjected to water treatment at 45.0℃. The reaction was carried out for 5.0 h to obtain a hydrolyzed silane solution. 20.0 g of mesoporous silica nanoparticles and 10.0 g of silica nanoparticles were added to 50.0 g of ethanol and ultrasonically dispersed for 30 min to obtain mixture A. 3.0 g of perfluoropolyether-based polyhedral oligomeric silsesquioxane and 5.0 g of polydimethylsiloxane grafted with trifluoropropylsilsesquioxane were added to 30.0 g of ethanol and stirred until completely dissolved to obtain mixture B. Mixture A and mixture B were added sequentially to the hydrolyzed silane solution and stirred at 400 r / min for 5.0 h at 45.0 °C to obtain the coating solution. The pretreated photovoltaic glass is vertically immersed in the coating solution and held for 30 seconds. Then it is pulled out of the liquid surface at a speed of 100 mm / min to obtain the coated glass. The coated glass is then sent to a heat treatment furnace, first dried at 80.0℃ for 10 min, then pre-cured at 150.0℃ for 17 min, and finally heat-treated at 280.0℃ for 1.5 h to obtain anti-reflective self-cleaning coated photovoltaic glass.

[0039] Example 2

[0040] This embodiment provides a method for preparing anti-reflective self-cleaning coated photovoltaic glass, the steps of which include: Preparation of perfluoropolyether-based polyhedral oligomeric silsesquioxanes: First, 8.0 g of aminopropyl isobutyl silsesquioxane and 10.5 g of perfluoropolyether acyl fluoride were dissolved in 40.0 g of toluene. Under ice-water bath cooling and nitrogen protection, 3.0 g of triethylamine was slowly added. The reaction system was then allowed to return to room temperature and stirred continuously for 6.0 h. After the reaction was completed, most of the solvent was removed by vacuum distillation to obtain the crude product. The crude product was redissolved in 60.0 mL of dichloromethane and washed successively with 40.0 mL of deionized water and 40.0 mL of 0.1 mol / L dilute hydrochloric acid. The organic phases were combined and dried with 4.0 g of anhydrous magnesium sulfate. Finally, the product was purified by silica gel column chromatography to obtain perfluoropolyether-based polyhedral oligomeric silsesquioxanes.

[0041] Preparation of polydimethylsiloxane-grafted trifluoropropylsilsesquioxane: 8.0 g of monohydroxy-terminated polydimethylsiloxane was mixed with 20.0 g of trifluoropropanetrimethoxysilane, and 40.0 g of toluene and 0.16 g of dibutyltin dilaurate were added. The mixture was refluxed at 105.0 °C for 2.0 h to obtain a reaction mixture. The reaction mixture was cooled to 68.0 °C, and 4.0 g of methyltrimethoxysilane and 0.4 g of tetraisopropyl titanate were added. The reaction was continued for 4.0 h. After the reaction was completed, the mixture was cooled to 25.0 °C, and the solvent was removed by rotary evaporator to obtain a viscous liquid. The viscous liquid was dissolved in 40.0 g of tetrahydrofuran, and precipitated by dropwise addition of 150.0 g of methanol. The precipitate was collected by filtration and dried in a vacuum oven at 58.0 °C for 12.0 h to obtain polydimethylsiloxane-grafted trifluoropropylsilsesquioxane.

[0042] Preparation of antireflective self-cleaning coated photovoltaic glass: A photovoltaic glass substrate (100mm × 100mm × 3mm) was ultrasonically cleaned for 15 minutes with 80.0g deionized water and 3.0g neutral detergent, then rinsed with 40.0g ethanol, dried with nitrogen, and finally treated with ultraviolet ozone for 8 minutes to obtain pretreated photovoltaic glass. 0.5g of γ-glycidyl etheroxypropyltrimethoxysilane was added to 50.0g ethanol and 1.0g deionized water. The mixture was stirred at 300r / min, and the pH was adjusted to 3.0 with dilute hydrochloric acid. The mixture was then subjected to water treatment at 44.0℃. The reaction was carried out for 4.0 h to obtain a hydrolyzed silane solution. 10.0 g of mesoporous silica nanoparticles and 5.0 g of silica nanoparticles were added to 30.0 g of ethanol and ultrasonically dispersed for 20 min to obtain mixture A. 1.0 g of perfluoropolyether-based polyhedral oligomeric silsesquioxane and 2.0 g of polydimethylsiloxane grafted with trifluoropropylsilsesquioxane were added to 20.0 g of ethanol and stirred until completely dissolved to obtain mixture B. Mixture A and mixture B were added sequentially to the hydrolyzed silane solution and stirred at 400 r / min for 4.0 h at 44.0 °C to obtain the coating solution. The pretreated photovoltaic glass is vertically immersed in the coating solution and held for 20 seconds. Then it is pulled out of the liquid surface at a speed of 80 mm / min to obtain the coated glass. The coated glass is then sent to a heat treatment furnace, where it is first dried at 78.0℃ for 8 minutes, then pre-cured at 145.0℃ for 15 minutes, and finally heat-treated at 275.0℃ for 1 hour to obtain anti-reflective self-cleaning coated photovoltaic glass.

[0043] Example 3

[0044] This embodiment provides a method for preparing anti-reflective self-cleaning coated photovoltaic glass, the steps of which include: Preparation of perfluoropolyether-based polyhedral oligomeric silsesquioxanes: First, 12.0 g of aminopropyl isobutyl silsesquioxane and 16.5 g of perfluoropolyether acyl fluoride were dissolved in 60.0 g of toluene. Under ice-water bath cooling and nitrogen protection, 4.5 g of triethylamine was slowly added. The reaction system was then allowed to return to room temperature and stirred continuously for 8.0 h. After the reaction was completed, most of the solvent was removed by vacuum distillation to obtain the crude product. The crude product was redissolved in 100.0 mL of dichloromethane and washed successively with 60.0 mL of deionized water and 60.0 mL of 0.5 mol / L dilute hydrochloric acid. The organic phases were combined and dried with 6.0 g of anhydrous magnesium sulfate. Finally, the product was purified by silica gel column chromatography to obtain perfluoropolyether-based polyhedral oligomeric silsesquioxanes.

[0045] Preparation of polydimethylsiloxane-grafted trifluoropropylsilsesquioxane: 12.0 g of monohydroxyl-terminated polydimethylsiloxane was mixed with 30.0 g of trifluoropropanetrimethoxysilane, 60.0 g of toluene and 0.24 g of dibutyltin dilaurate were added, and the mixture was refluxed at 115.0 °C for 2.0 h to obtain a reaction mixture. The reaction mixture was cooled to 72.0 °C, and 6.0 g of methyltrimethoxysilane and 0.6 g of tetraisopropyl titanate were added, and the reaction was continued for 6.0 h. After the reaction was completed, the mixture was cooled to 25.0 °C, and the solvent was removed by rotary evaporator to obtain a viscous liquid. The viscous liquid was dissolved in 60.0 g of tetrahydrofuran, and precipitated by dropwise addition of 250.0 g of methanol. The precipitate was collected by filtration and dried in a vacuum oven at 62.0 °C for 12.0 h to obtain 18.0 g of polydimethylsiloxane-grafted trifluoropropylsilsesquioxane.

[0046] Preparation of antireflective self-cleaning coated photovoltaic glass: A photovoltaic glass substrate (100mm × 100mm × 3mm) was ultrasonically cleaned for 25 minutes with 120.0g deionized water and 7.0g neutral detergent, then rinsed with 60.0g ethanol, dried with nitrogen, and finally treated with ultraviolet ozone for 12 minutes to obtain pretreated photovoltaic glass. 3.0g of γ-glycidyl etheroxypropyltrimethoxysilane was added to 80.0g ethanol and 5.0g deionized water. The mixture was stirred at 300r / min, and the pH was adjusted to 4.0 with dilute hydrochloric acid. The mixture was then subjected to water treatment at 46.0℃. The reaction was carried out for 6.0 h to obtain a hydrolyzed silane solution. 30.0 g of mesoporous silica nanoparticles and 15.0 g of silica nanoparticles were added to 60.0 g of ethanol and ultrasonically dispersed for 40 min to obtain mixture A. 5.0 g of perfluoropolyether-based polyhedral oligomeric silsesquioxane and 8.0 g of polydimethylsiloxane grafted with trifluoropropylsilsesquioxane were added to 40.0 g of ethanol and stirred until completely dissolved to obtain mixture B. Mixture A and mixture B were added sequentially to the hydrolyzed silane solution and stirred at 400 r / min for 6.0 h at 46.0 °C to obtain the coating solution. The pretreated photovoltaic glass was vertically immersed in the coating solution and held for 40 seconds. Then it was pulled out of the solution at a speed of 120 mm / min to obtain the coated glass. The coated glass was then sent to a heat treatment furnace, where it was first dried at 82.0℃ for 12 minutes, then pre-cured at 155.0℃ for 20 minutes, and finally heat-treated at 285.0℃ for 2.0 hours to obtain anti-reflective self-cleaning coated photovoltaic glass.

[0047] Comparative Example 1 The difference between this comparative example and Example 1 is that the preparation of antireflective self-cleaning coated photovoltaic glass is as follows: the steps are basically the same as in Example 1, but perfluoropolyether-based polyhedral oligomeric silsesquioxane is not added, that is, mixture B contains only 5.0g of polydimethylsiloxane grafted with trifluoropropylsilsesquioxane, and the other raw materials and their quality are exactly the same as in Example 1.

[0048] Comparative Example 2 The difference between this comparative example and Example 1 is that the preparation of antireflective self-cleaning coated photovoltaic glass is as follows: the steps are basically the same as in Example 1, but polydimethylsiloxane grafted with trifluoropropylsilsesquioxane is not added, that is, mixture B contains only 3.0g of perfluoropolyether-based polyhedral oligomeric silsesquioxane, and the other raw materials and their quality are exactly the same as in Example 1.

[0049] Comparative Example 3 The difference between this comparative example and Example 1 is that the preparation of anti-reflective self-cleaning coated photovoltaic glass is basically the same as that in Example 1, but mesoporous silica nanoparticles are not added. Only 10.0g of silica nanoparticles are used (the total amount is the same as the mass of silica nanoparticles in Example 1). Other raw materials and their masses are exactly the same as in Example 1.

[0050] The performance of the antireflective self-cleaning coated photovoltaic glasses obtained in Examples 1-3 and Comparative Examples 1-3 was tested according to national and industry standard testing specifications. This invention systematically tested the performance of the coated photovoltaic glass samples prepared in Examples 1-3 and Comparative Examples 1-3. All tests were conducted in a constant temperature and humidity environment, with the ambient temperature controlled at 23℃±2℃ and the relative humidity controlled at 50%±5%. Before testing, the surface of each sample was cleaned with anhydrous ethanol and dried with high-purity nitrogen to ensure no contaminants remained on the surface.

[0051] Optical performance testing was performed using a UV-Vis-NIR spectrophotometer equipped with an integrating sphere. The measurement wavelength range was 380 nm to 1100 nm to simulate the solar spectrum. A xenon lamp was used as the light source, with the beam incident on the sample surface at an 8° angle. Transmitted and reflected light were collected by the integrating sphere, and the data were analyzed by the spectrometer. Each sample was measured five times at different locations, and the average photovoltaic transmittance and reflectance were calculated.

[0052] Self-cleaning performance was evaluated using a contact angle meter and a contaminant removal test. First, 2 μL of ultrapure water was dropped onto the sample surface using a microsyringe. The droplet morphology was recorded using a video system, and the static contact angle was calculated. Next, a roll-off angle test was performed using an inclined platform, recording the average tilt angle at which the droplet began rolling at three different locations. Finally, a contaminant removal test was conducted. Arizona test dust was evenly distributed onto the sample surface, followed by rinsing with a small amount of deionized water (0.5 mL) dripped at a 45° angle. The removal rate of surface contaminants was recorded to quantify its self-cleaning efficiency.

[0053] Mechanical performance tests include pencil hardness test (1kg load, pencil grade from 9B to 9H, with the highest hardness that does not scratch the film layer as the standard), adhesion test (cross-cut test, a hard blade cuts a 1mm×1mm grid on the film layer surface, and after the 3M tape is peeled off, the grade is rated according to the area of ​​peeling off, from 0 to 5), and abrasion resistance test (friction tester, 500g load, the light transmittance is measured after the friction wheel rotates 200 times).

[0054] Durability tests included acid resistance (immersion in 1 mol / L HCl solution for 24 h), alkali resistance (immersion in 1 mol / L NaOH solution for 24 h), neutral salt spray test (5% NaCl solution, temperature 35℃, duration 96 h), ultraviolet radiation test (UV lamp array, total radiation 60 kW⋅h), damp heat test (temperature 85℃, relative humidity 85%, duration 1000 h), thermal cycling test (temperature cycling range −40℃ to 85℃, 200 cycles), and scrubbing resistance test (scrubber, 1000 scrubs). After all durability tests, the transmittance change of the sample at 550 nm was measured, and scanning electron microscopy was used to observe whether the film layer showed signs of peeling, blistering, or other phenomena.

[0055] The film thickness was determined by cross-sectional analysis using a scanning electron microscope, and the color difference (ΔEab value) was measured using a spectrophotometer. All testing equipment was calibrated using standard calibration plates, and five measurements were taken at each sample, with the average value recorded.

[0056] The performance test data above are shown in Table 1.

[0057] Table 1 Performance Test Results

[0058]

[0059]

[0060] The test results in Table 1 clearly demonstrate that Examples 1-3, through innovative material combinations and structural designs, systematically solved a long-standing technical challenge in the field of photovoltaic glass antireflective films: how to balance excellent self-cleaning function and long-term environmental durability while improving light transmittance. Specifically, the advantages of their solutions are reflected in the following core aspects: Firstly, regarding the synergistic improvement of optical performance and structural stability, the embodiment constructs a gradient refractive index structure by introducing mesoporous silica nanoparticles and innovatively uses perfluoropolyether-based polyhedral oligomeric silsesquioxane and polydimethylsiloxane grafted with trifluoropropylsilsesquioxane as key functional components, successfully achieving a balance between high transmittance and high mechanical stability. Test data shows that the average transmittance of the embodiment is as high as 95.5% or more, significantly higher than that of the comparative examples (especially comparative example 3, which lacks a mesoporous structure and has a transmittance of only 89.5%). More importantly, its film layer forms a unique "dense layer-porous layer" composite structure. The dense layer at the top (mainly composed of functional siloxanes) effectively protects the antireflective porous layer at the bottom, which is composed of mesoporous silica, so that while maintaining a low refractive index, the transmittance decrease after the abrasion test is less than 0.5%, the pencil hardness reaches 4H or higher, and the adhesion is grade 0. In contrast, Comparative Examples 1 and 2, lacking the perfluoropolyether and polydimethylsiloxane components respectively, resulted in insufficient crosslinking density and toughness of the film layers, significantly reduced adhesion to level 2 or 3, and substantial deterioration in wear resistance. This confirms that the examples, through the synergistic effect of the components, solved the common problem of poor mechanical strength in traditional porous antireflective films.

[0061] Secondly, regarding self-cleaning performance and chemical stability, the examples demonstrated a perfect combination of superhydrophobic properties and excellent weather resistance. The water contact angles of the examples were all greater than 155°, the roll-off angles were less than 6°, and the surface contaminant removal rate was over 97%, meeting the superhydrophobic standard. This is mainly due to the low surface energy enrichment layer formed by the perfluoropolyether segments on the film surface, and the reduction of the coating surface energy by the polydimethylsiloxane segments. In contrast, Comparative Example 1, lacking the perfluoropolyether component, experienced a sharp drop in water contact angle to 105°, essentially losing its self-cleaning function; Comparative Example 2, lacking the polydimethylsiloxane component, suffered damage to its surface structure integrity, with the roll-off angle increasing to 30°, resulting in a significant decrease in hydrophobic performance. In durability testing, the transmittance of the examples did not decrease by more than 0.7% after undergoing harsh environmental tests such as UV radiation, salt spray, and acid / alkali immersion. Furthermore, after alkali resistance, damp heat, and thermal cycling tests, the transmittance decrease was also less than 1.0%, and the color difference ΔEab value was less than 1.3, far superior to the comparative examples (comparative examples 1 and 2 showed a decrease of more than 2.5% and a ΔEab greater than 2.8 after UV testing). This indicates that the perfluoropolyether and polydimethylsiloxane components in the examples not only provide initial hydrophobicity, but their stable chemical structure (such as the high bond energy of CF bonds and the high stability of the Si-O-Si network) ensures that the film layer can effectively resist the erosion of ultraviolet rays, moisture, and corrosive pollutants under long-term outdoor exposure, solving the problems of insufficient weather resistance and easy aging failure of traditional self-cleaning coatings.

[0062] Finally, regarding the environmental friendliness and long-term reliability of the process, the embodiment employs an aqueous-phase-based coating solution formulation and an optimized heat treatment process, enhancing safety while ensuring the long-term stability of the film. Compared to existing coating solutions that commonly use flammable organic solvents (such as alcohols), the embodiment significantly improves the inherent safety of the production process and reduces VOC emissions. More importantly, by precisely controlling the heat treatment process (including pre-curing and final high-temperature treatment), the silane hydrolysis-condensation reaction is promoted, forming a robust Si-O-Si covalent bond network between nanoparticles and between the film and the glass substrate. This maintains stable performance, thus solving the technical pain point of ordinary anti-reflective films being prone to cracking and peeling in outdoor environments with frequent temperature changes, providing a reliable guarantee for photovoltaic modules to maintain high power generation efficiency throughout their entire lifecycle.

[0063] In summary, Examples 1-3 successfully overcame the industrial bottleneck of achieving high light transmittance, strong self-cleaning, and high durability simultaneously through the ingenious combination and synergistic effect of mesoporous silica nanoparticles, perfluoropolyether-based polyhedral oligomeric silsesquioxane, and polydimethylsiloxane grafted with trifluoropropylsilsesquioxane. The prepared coated glass has significant comprehensive advantages and application prospects.

Claims

1. A method for preparing anti-reflective self-cleaning coated photovoltaic glass, characterized in that the steps include... include: S1. The photovoltaic glass substrate is ultrasonically cleaned with deionized water and neutral detergent, then rinsed with ethanol, dried with nitrogen, and finally treated with ultraviolet ozone to obtain pretreated photovoltaic glass; γ-glycidyl etheroxypropyltrimethoxysilane is added to ethanol and deionized water, and the pH is adjusted to 3-4 under stirring. Hydrolysis reaction is carried out at 44-46℃ to obtain hydrolyzed silane solution; mesoporous silica nanoparticles and silica nanoparticles are added to ethanol and ultrasonically dispersed to obtain mixture A; perfluoropolyether-based polyhedral oligomeric silsesquioxane and polydimethylsiloxane grafted with trifluoropropylsilsesquioxane are added to ethanol and stirred until completely dissolved to obtain mixture B; mixture A and mixture B are added sequentially to the hydrolyzed silane solution and stirred at 44-46℃ to obtain coating solution; S2. Immerse the pretreated photovoltaic glass vertically into the coating solution, let it stand, and then pull it out of the liquid surface to obtain the coated glass. Send the coated glass into a heat treatment furnace, first dry it at 78-82℃, then pre-cur it at 145-155℃, and finally heat treat it at 275-285℃.

2. The method for preparing anti-reflective self-cleaning coated photovoltaic glass according to claim 1, characterized in that, In step S1, the stirring time is 4-6 hours at 44-46℃.

3. The method for preparing anti-reflective self-cleaning coated photovoltaic glass according to claim 1, characterized in that, In step S2, the pre-curing time at 145-155℃ is 15-20 min; the heat treatment time at 275-285℃ is 1-2 h.

4. The method for preparing anti-reflective self-cleaning coated photovoltaic glass according to claim 1, characterized in that, The preparation method of the perfluoropolyether-based polyhedral oligomeric silsesquioxane includes: A1. Dissolve aminopropyl isobutylsilsesquioxane and perfluoropolyether fluoride in toluene, add triethylamine under ice-water bath cooling and nitrogen protection, heat to room temperature, and stir continuously. A2. After the reaction is complete, the crude product is obtained by vacuum distillation. The crude product is redissolved in dichloromethane and washed successively with deionized water and dilute hydrochloric acid. The organic phases are combined and dried over anhydrous magnesium sulfate. Finally, the product is purified by column chromatography.

5. The method for preparing anti-reflective self-cleaning coated photovoltaic glass according to claim 4, characterized in that, In step A1, the molar ratio of aminopropyl isobutylsilsesquioxane, perfluoropolyether fluoride and triethylamine is 1:(1.05-1.2):(1.10-1.30); the stirring time is 6-8h.

6. The method for preparing anti-reflective self-cleaning coated photovoltaic glass according to claim 4, characterized in that, In step A2, the concentration of the dilute hydrochloric acid is 0.1-0.5 mol / L.

7. The method for preparing anti-reflective self-cleaning coated photovoltaic glass according to claim 1, characterized in that, The preparation method of the polydimethylsiloxane grafted with trifluoropropylsilsesquioxane includes: B1. Mix monohydroxy-terminated polydimethylsiloxane with trifluoropropanetrimethoxysilane, add toluene and dibutyltin dilaurate, and reflux at 105-115℃ to obtain the reaction mixture. B2. Cool the reaction mixture to 68-72℃, add methyltrimethoxysilane and tetraisopropyl titanate, continue the reaction to obtain the reaction mixture, cool the reaction mixture to room temperature, and obtain a viscous liquid by rotary evaporation. Then dissolve the viscous liquid in tetrahydrofuran and add it dropwise to methanol to precipitate. Filter to collect the precipitate and dry the precipitate in a vacuum oven at 58-62℃.

8. The method for preparing anti-reflective self-cleaning coated photovoltaic glass according to claim 7, characterized in that, In step B1, the molar ratio of monohydroxy-terminated polydimethylsiloxane, trifluoropropanetrimethoxysilane and dibutyltin dilaurate is 1:(2.5-3.5):(0.01-0.03).

9. The method for preparing anti-reflective self-cleaning coated photovoltaic glass according to claim 7, characterized in that, In step B2, the reaction continues for 4-6 hours.

10. An anti-reflective self-cleaning coated photovoltaic glass prepared by the method according to any one of claims 1-9, characterized in that, The raw materials include the following parts by weight: 10-30 parts mesoporous silica nanoparticles; 5-15 parts silica nanoparticles; 1-5 parts perfluoropolyether-based polyhedral oligomeric silsesquioxane; 2-8 parts polydimethylsiloxane grafted with trifluoropropylsilsesquioxane; 0.5-3 parts γ-glycidyl etheroxypropyltrimethoxysilane; 50-80 parts ethanol; and 1-5 parts deionized water.

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