CN110606670A - A preparation method of wide-spectrum anti-reflection superhydrophobic photovoltaic glass - Google Patents

Abstract

The invention discloses a preparation method of a wide-spectrum anti-reflection super-hydrophobic photovoltaic glass. A two-step method is adopted to prepare a wide-spectrum anti-reflection super-hydrophobic photovoltaic glass. Firstly, an aluminum oxide film with a porous structure is prepared on the glass, and then filled in the porous structure. Silicon oxide nanoparticles with a size of a few nanometers to tens of nanometers, and using heptadecafluorodecyltrimethoxysilane to reduce the surface energy of the silicon oxide nanoparticles. The wide-spectrum anti-reflection super-hydrophobic film layer prepared on the surface of photovoltaic glass has a dual-scale structure. The preparation method of this simple and low-cost anti-reflection super-hydrophobic film layer is suitable for industrial applications such as photovoltaic glass, curtain wall glass, and automotive glass. effective solution.

Description

A preparation method of wide-spectrum anti-reflection superhydrophobic photovoltaic glass

technical field

The invention belongs to the technical field of photovoltaics, and in particular relates to a preparation method of a wide-spectrum anti-reflection superhydrophobic photovoltaic glass.

Background technique

With the increasingly prominent problems of resource unsustainability and environmental pollution, photovoltaic power generation has become the main choice for future new energy development due to the characteristics of solar energy, which is rich in resources, widely distributed, and environmentally friendly. emerging industries that are developing. The cost of photovoltaic power generation depends on the photoelectric conversion efficiency of photovoltaic modules. The higher the efficiency of the modules, the lower the cost of power generation. The efficiency of solar cells is the decisive factor of module efficiency. At present, the highest conversion efficiency of crystalline silicon cells has reached 26.7%, which is very close to its theoretical conversion rate of 29.3%. The space for further improvement of cell efficiency is getting smaller and smaller. Since photovoltaic modules are installed outdoors, dust is easy to accumulate on the surface of the photovoltaic glass protecting the modules, which greatly reduces the light transmittance of the glass and ultimately reduces the conversion efficiency of photovoltaic modules. Studies have shown that when photovoltaic modules are installed outdoors with a dust deposition density of 0.1-10g/m ² , the efficiency of the modules will drop by 30% after 5 months. In order to keep the output power of photovoltaic modules in the best state, the dust on the modules should be removed regularly, but this will increase the cost of photovoltaic power generation. In addition, the optical transmittance of photovoltaic glass also has a great influence on the efficiency of modules. At present, the mainstream photovoltaic glass is mainly low-iron tempered suede glass, and the optical transmittance in the wavelength range of 400-1100nm reaches 92%. However, there is still 8% room for improvement in the transmittance. Therefore, by improving the optical transmittance of photovoltaic glass and the cleanliness of photovoltaic modules during long-term outdoor operation, it is easier than developing crystalline silicon cells with higher conversion rates, and the cost is much lower.

There are two ways to reduce the solar reflection of photovoltaic glass. In the first method, the glass surface is coated with a single-layer or multi-layer film of a certain thickness, and the reflected light is eliminated by using the principle of light interference. Since sunlight is composite light with a broad spectrum, a single-layer anti-reflection coating can only have a complete anti-reflection effect on monochromatic light of a specific wavelength in sunlight, and only a partial anti-reflection effect on light of other wavelengths. Although the anti-reflection effect can be improved by multi-layer coating technology, the cost is high. The second method is to prepare a nanostructured film on the surface of the glass, which has better anti-reflection properties than multi-layer anti-reflection coatings. down to 1%.

Since the gap between nanoclusters (such as nanowires, nanorods, nanocolumns, etc.) is much smaller than the wavelength of visible light and infrared light, the nanostructured film layer can be equivalent to a material with a refractive index between air and nanoclusters. For a single homogeneous thin film, the refractive index decreases with the increase of porosity, the light enters the equivalent refraction field, the optical resonance disappears, and no diffraction occurs. The film with nanostructure has the characteristics of this gradient of refractive index, which can fundamentally eliminate the Fresnel reflection at the interface between the film and the air, and thus has the anti-reflection characteristics of wide-band and wide-angle. The anti-reflection properties of nanostructures depend on the size of the nanostructures, and gradually degrade with the increase of the periodic size of the structures. When the size of the nanostructure is close to or larger than the wavelength of the incident light, which is the so-called textured structure, although the anti-reflection performance induced by the refractive index gradient characteristic disappears, the incident light can be reflected multiple times on the substrate surface, increasing the light absorption. Thereby reducing surface reflections.

The self-cleaning function of the lotus leaf surface is well known and is due to its surface superhydrophobic properties. There are a large number of micron-scale waxy papillae structures distributed on the surface of lotus leaves. This waxy substance has low surface energy. structure), this micro-nano structure is the key factor to form a super-hydrophobic surface. This special structure can effectively form an air layer, greatly reducing the contact area between the surface of the lotus leaf and water droplets, dust, etc., reducing the rolling angle, making it easy for water droplets to roll off the surface of the lotus leaf, and taking away the dust on the surface of the lotus leaf , It has the function of automatically cleaning the surface of the lotus leaf. The preparation method of artificial superhydrophobic surface structure is generally to form micro-nano structure on the surface first, and then carry out low surface energy modification. Low surface energy is a prerequisite for the formation of superhydrophobic surfaces, and the surface micro-nanostructure is the determinant of superhydrophobic performance.

Constructing a low surface energy film with a micro-nano structure on the surface of photovoltaic glass can greatly reduce the reflection of sunlight on the glass surface and increase the optical transmittance of the glass. It can maintain the cleanliness of the glass surface under washing, and has the function of self-cleaning. The anti-reflection effect of the surface of nanostructures on sunlight is better than that of microstructures, and the surface of micronano-composite structures has better hydrophobic properties, but the existence of microstructures will have an adverse effect on the optical transmittance of glass, so high light transmittance It is contradictory with superhydrophobic properties.

At present, there are two main ways to prepare anti-emission superhydrophobic glass surface, one is to coat inorganic oxides such as silicon dioxide or titanium dioxide on the glass surface, and the other is to directly form a micro-nano composite structure on the glass surface. The first method is that the durability of the surface is weak because the porous structure formed by the accumulation of nanoparticles endows the superhydrophobic surface with anti-reflection properties on the surface. The second method is to form a porous structure on the glass surface through a wet or dry etching process, which has excellent hydrophobic properties but poor optical transmission properties. How to obtain broad-spectrum anti-reflection superhydrophobic photovoltaic glass by improving the preparation method of the surface microstructure and optimizing the surface structure is an urgent problem in the photovoltaic industry.

The aluminum oxide film has a strong bonding force with the glass substrate, and has excellent properties such as high optical transmittance, scratch resistance, and wear resistance. Therefore, in the present invention, alumina is used as a modified material for transparent hydrophobic photovoltaic glass. In order to improve the surface roughness of the aluminum oxide film, a micro-nano composite porous structure was obtained by low-temperature hydrothermal treatment. In order to improve the optical transmittance of the glass, nanoparticles such as silicon oxide, titanium oxide, and zinc oxide are filled in the porous structure. Finally, in order to reduce the surface energy, organic polymers such as alkoxy silicon salts, alkoxy polymers, and fluorides can be used for modification treatment, and finally a broad-spectrum anti-reflection superhydrophobic photovoltaic glass can be obtained.

Contents of the invention

The purpose of the present invention is to provide a preparation method of wide-spectrum anti-reflection superhydrophobic photovoltaic glass.

The general idea of the present invention is to prepare wide-spectrum anti _- reflection superhydrophobic photovoltaic glass by _two -step method. Silicon oxide (SiO ₂ ) nanoparticles of tens of nanometers, and use heptadecafluorodecyltrimethoxysilane to reduce the surface energy of the silicon oxide nanoparticles.

Specifically, the present invention adopts the following technical solutions:

A preparation method of wide-spectrum anti-reflection superhydrophobic photovoltaic glass, comprising the steps of:

1) Glass substrate cleaning and hydroxylation treatment: immerse the cleaned glass substrate in a mixture of concentrated sulfuric acid and hydrogen peroxide, the volume ratio of the two is 4:9, ultrasonically oscillate for 1 to 3 hours at room temperature, take it out and clean it again. Dry;

2) Preparation of alumina sol: Mix aluminum trichloride hexahydrate and absolute ethanol at a molar ratio of 1:20 to 30, stir well, and then mix acetylacetone (the mixture of acetylacetone and aluminum trichloride hexahydrate) The molar ratio is 3:1) slowly added dropwise to the above mixed solution, stirred for 1~2h, and then added an anionic surfactant (the molar number of which is 0.1~1.0% of that of aluminum chloride hexahydrate), and heated in a water bath at 65°C Stir for 1 to 2 hours to obtain a uniformly dispersed alumina sol;

3) Preparation of porous alumina film: apply the alumina sol obtained in step 2) to the glass substrate obtained in step 1) by spin coating, and the thickness is controlled in the range of 150-250 μm; after the coating is completed, the substrate Put the sheet into a muffle furnace for low-temperature annealing, the annealing temperature is 400-450°C, and the annealing time is 60-90 minutes; wash and dry after annealing;

4) Preparation of nano-silica sol: under the conditions of constant temperature water bath at 60°C and magnetic stirring, slowly dissolve an appropriate amount of L-lysine in a mixed solution of isopropanol and deionized water, and then dissolve ethyl orthosilicate Slowly add it dropwise into the mixed solution, stirring for 2-3 hours, and then let it stand for 10 hours; in the above solution, the molar ratio of ethyl orthosilicate, L-lysine, isopropanol and deionized water is 1: 0.01～0.03:2.5:150～300;

5) Preparation of fluorine-modified nano-silica sol: Add heptadecafluorodecyltrimethoxysilane and ethanol to the nano-silica sol obtained in step 4), and stir magnetically for 2 hours in a constant temperature water bath environment at 60° C.; wherein, The molar ratio of ethyl orthosilicate, heptadecafluorodecyltrimethoxysilane and ethanol is 1:1～3:5～8;

6) Apply the fluorine-modified nano-silica sol obtained in step 5) to the glass substrate obtained in step 3) by spin coating, then dry the substrate in an electric oven at a temperature of 80°C for 30 minutes, and put it in Low temperature annealing in muffle furnace for 2h, the annealing temperature is 200°C.

The wide-spectrum anti-reflection super-hydrophobic film layer prepared on the surface of the photovoltaic glass has a double-scale structure. During the low-temperature hydrothermal treatment of alumina film, a three-dimensional cross-linked network porous structure with nanopores is formed, and silica nanoparticles are attached to the nanopore structure, which reduces the size of the pore structure and reduces the surface friction. reflection. The average transmittance of the film layer in the wavelength range of 400-1100nm is 96.44%, and the surface contact angle is 161.8 ⁰ . In addition, the film layer has strong corrosion resistance and durability. The preparation method of this simple and low-cost anti-reflection superhydrophobic film layer is an effective solution for industrial applications such as photovoltaic glass, curtain wall glass, and automotive glass.

Description of drawings

Below in conjunction with accompanying drawing and embodiment of the present invention will be described in further detail

Figure 1 is a schematic diagram of the preparation process of broad-spectrum anti-reflection superhydrophobic photovoltaic glass;

Figure 2 shows the optical transmittance of broad-spectrum anti-reflection superhydrophobic photovoltaic glass.

Detailed ways

1. Main experimental raw materials and equipment

Glass substrate: 40mm×40mm×0.2mm, ultra-clear float low-iron glass, visible light transmittance is 91%;

Aluminum trichloride hexahydrate (AlCl ₃ 6H ₂ O): 99%;

Acetylacetone (C ₅ H ₈ O ₂ ): 99.5%;

Orthoethyl silicate (TEOS, C ₈ H ₂₀ O ₄ Si): 99%;

L-lysine (L-lysine): 98%

Heptadecafluorodecyltrimethoxysilane (1H,1H,2H,2H-Perfluorodecyltrimethoxysilane): 97%;

Sodium dodecylbenzenesulfonate (DBS): 95%;

Commonly used chemical reagents such as sulfuric acid, hydrogen peroxide, absolute ethanol, isopropanol: analytically pure;

Deionized water: resistivity greater than 18.2MΩ.cm;

Magnetic stirrer, electric heating oven, ultrasonic cleaning machine, muffle furnace, electric heating constant temperature water tank, spin coater, etc.;

Contact angle tester, UV visible near infrared spectrophotometer.

2. Glass substrate cleaning and hydroxylation treatment

In order to increase the hydrophilicity of the glass surface and enhance the bonding force between the aluminum oxide film and the glass substrate, surface hydroxylation treatment is required. The specific method is:

First, cleaning, first use detergent solution to ultrasonically clean for 30 minutes, then rinse with tap water for many times until there is no bubble, and then wash with deionized water for several times until the conductivity of the water is close to that of deionized water;

Second, surface hydroxylation treatment, immerse the cleaned glass substrate in concentrated sulfuric acid and hydrogen peroxide with a volume mixing ratio of 4:9, ultrasonically oscillate for 1 to 3 hours at room temperature, take it out, rinse it repeatedly with deionized water, and dry it with nitrogen spare.

3. Preparation of alumina sol

Mix aluminum trichloride hexahydrate and absolute ethanol in a molar ratio of 1:20 to 30, stir well, and then add acetylacetone (the molar ratio of acetylacetone to aluminum trichloride hexahydrate is 3:1) Slowly add it dropwise into the above mixed solution, and stir it magnetically for 1-2 hours. Afterwards, add a small amount of anionic surfactant—sodium dodecylbenzenesulfonate (the molar number is 0.1-1.0% of aluminum chloride hexahydrate), in Stir in a water bath at 65°C for 1 to 2 hours to finally obtain a uniformly dispersed alumina sol.

4. Preparation of porous alumina film

The prepared alumina sol is coated on the glass substrate whose surface has undergone hydroxylation treatment by spin coating method, and the thickness of the spin coating solution is adjusted by the rotation speed and time of the turntable, and the thickness is controlled in the range of 150-250 μm. After the coating is completed, the substrate is put into a muffle furnace for low-temperature annealing, the annealing temperature is 400-450° C., and the annealing time is 60-90 minutes. After annealing, let the furnace cool down to room temperature naturally, take out the glass substrate, then put it into deionized water at a temperature of 80-95°C for hydrothermal treatment for 15-25 minutes, rinse with ionized water after completion, and blow dry with nitrogen.

5. Preparation of nano-silica sol

Under the conditions of a constant temperature water bath at 60°C and magnetic stirring, slowly dissolve an appropriate amount of L-lysine in a mixed solution of isopropanol and deionized water, then slowly add tetraethyl orthosilicate into the mixed solution, and stir The reaction time is 2 to 3 hours, and then stand for 10 hours. In the above solution, the molar ratio of ethyl orthosilicate, L-lysine, isopropanol and deionized water is 1:0.01-0.03:2.5:150-300. The particle size distribution of the silica nanospheres obtained by the above method is in the range of 5-30nm, and the particle size of the nanospheres can be regulated by changing the amount of reactants such as tetraethyl orthosilicate and L-lysine, for example , the amount of L-lysine increased, the particle size decreased, and the amount of ethyl orthosilicate increased, the particle size increased.

6. Preparation of fluorine-modified nano-silica sol

Add appropriate amount of heptadecafluorodecyltrimethoxysilane and ethanol to the nano-silica sol, and stir magnetically for 2 hours in a constant temperature water bath environment at 60°C. Under this process condition, the molar ratio of ethyl orthosilicate, heptadecafluorodecyltrimethoxysilane and ethanol is 1:1～3:5～8.

7. Preparation of broad-spectrum anti-reflection superhydrophobic photovoltaic glass

Using the spin coating method, the fluorine-modified nano-silica sol is coated on the glass substrate with a porous alumina film on the surface, and then the substrate is dried in an electric oven at a temperature of 80°C for 30 minutes, and then placed in a muffle furnace at a low temperature. Annealing 2h, the annealing temperature is 200 ℃.

8. Performance testing

After the glass substrate treated by the above process, the scanning electron microscope (SEM) test shows that during the low-temperature hydrothermal treatment of the aluminum oxide film, a three-dimensional cross-linked network with nanopores (200-600nm in diameter) is formed. Porous structure, silica nanoparticles with an average particle size of 15nm are attached to the nanoporous structure, which reduces the size of the pore structure and forms a dual-scale structure. The optical transmittance of the glass substrate was tested with an ultraviolet-visible-near-infrared spectrophotometer. The average transmittance in the wavelength range of 400-1100nm was 96.44%, and the highest transmittance was 98.2%, as shown in Figure 2. At room temperature, the wettability of the obtained superhydrophobic surface was tested with 5 μl droplets. When the water droplets fell on the surface and stood for 5 seconds, the contact angle of the glass surface was 161.8°. After the glass substrate is soaked in an acidic solution (hydrochloric acid solution with a pH of 4.0) and an alkaline solution (sodium hydroxide solution with a pH of 10) for 48 hours, the decrease in light transmittance after corrosion is less than 1.0%. In addition, the surface film layer has passed the 5H pencil hardness test.

Claims (1)

1. A preparation method of wide-spectrum anti-reflection superhydrophobic photovoltaic glass, characterized in that: comprising the steps: 1) Glass substrate cleaning and hydroxylation treatment: immerse the cleaned glass substrate in a mixture of concentrated sulfuric acid and hydrogen peroxide, the volume ratio of the two is 4:9, ultrasonically oscillate for 1 to 3 hours at room temperature, take it out and clean it again. Dry; 2) Preparation of alumina sol: Mix aluminum trichloride hexahydrate and absolute ethanol at a molar ratio of 1:20 to 30, stir well, and then mix acetylacetone (the mixture of acetylacetone and aluminum trichloride hexahydrate) The molar ratio is 3:1) slowly added dropwise to the above mixed solution, stirred for 1-2 hours, then added an anionic surfactant (the molar number of which is 0.1-1.0% of that of aluminum trichloride hexahydrate), and heated in a water bath at 65°C Stir for 1 to 2 hours to obtain a uniformly dispersed alumina sol; 3) Preparation of porous alumina film: apply the alumina sol obtained in step 2) to the glass substrate obtained in step 1) by spin coating, and the thickness is controlled in the range of 150-250 μm; after the coating is completed, the substrate Put the sheet into a muffle furnace for low-temperature annealing, the annealing temperature is 400-450°C, and the annealing time is 60-90 minutes; wash and dry after annealing; 4) Preparation of nano-silica sol: under the conditions of constant temperature water bath at 60°C and magnetic stirring, slowly dissolve an appropriate amount of L-lysine in a mixed solution of isopropanol and deionized water, and then dissolve ethyl orthosilicate Slowly add it dropwise into the mixed solution, stir the reaction time for 2 to 3 hours, and then let it stand for 10 hours; in the above solution, the molar ratio of ethyl orthosilicate, L-lysine, isopropanol, and deionized water is 1: 0.01～0.03:2.5:150～300; 5) Preparation of fluorine-modified nano-silica sol: Add heptadecafluorodecyltrimethoxysilane and ethanol to the nano-silica sol obtained in step 4), and stir magnetically for 2 hours in a constant temperature water bath environment at 60° C.; wherein, The molar ratio of ethyl orthosilicate, heptadecafluorodecyltrimethoxysilane and ethanol is 1:1～3:5～8; 6) Apply the fluorine-modified nano-silica sol obtained in step 5) to the glass substrate obtained in step 3) by spin coating, then dry the substrate in an electric oven at a temperature of 80° C. for 30 minutes, and put it in Low temperature annealing in muffle furnace for 2h, the annealing temperature is 200°C.