Study On Preparation And Self-cleaning Performance Of SiO₂ Antireflection Films By Sol-gel Method

In this paper,SiO₂ antireflective film was prepared on the surface of photovoltaic glass by Sol-gel method.Through the study of SiO₂ antireflective film,acid-base catalytic SiO₂/TiO₂ film and PEG/PVP modified acid-catalytic Si O₂ film,and to study its hydrophobic and hydrophilic,prepared self-cleaning SiO₂ antireflection film with high transparent and high strength.?1?The films were prepared by sol-gel method using HCl and NH₃ · H₂ O as catalysts,determined by experiment,: the optimum molar ratio of TEOS,EtOH,HCl and H₂ O was 1:19:0.08:4,the best aging time was 3d,the hardness >6H,the transmittance of the film is only 4% higher than that blank glass;The optimum molar ratio of TEOS,EtOH,NH₃·H₂O and H₂ O was 1:35:0.876:2.5,the best aging time was 5d.hardness <1H,the transmittance of the film is about 10% higher than that of blank glass.SEM was used to observe the surface morphology of the films: the surface structure of the acid catalytic film is compact,sol particles is smaller,the film thickness is between 145 nm and 170nm;the surface structure of base catalysis film is even and smooth,the structure is loose,the particle size is between 35 nm and 40 nm,the thickness of the film is between 220 nm and 245 nm.?2?Two kinds of acid-base compound catalytic methods for the preparation of SiO₂ sol,the first method for the addition of HCl in the alkali sol,due to the local acidity is too strong,easy to produce yellow flocculent precipitate,the film surface particle size is uneven,effect the transmittance;Method two is the addition of acid sol to alkali sol,The optimal volume ratio of alkali sol and acid sol is 5:1,the concentration of H⁺ was 0.0389mol/L,and the hardness of the film is about 3H.The sol reaction is mild,does not produce flocculent precipitate,the film surface is flat and the particle size is uniform,the method two is better than the method one.The SiO₂ antireflective film prepared by acid-base composite catalysis has the advantages of high intensity of acid-catalyzed and high transmittance of base-catalyzed film.?3?On the basis of the preparation of SiO₂ antireflective film by acid-base composite catalysis,and then coated with a layer of TiO₂ film,preparation of high transmittance self-cleaning film.Configure the TiO₂ sol in the molar ratio of TBOT,EtOH,HCl,H₂ O is 1:25:0.7:4,when the molar ratio of TBOT and EtOH was 1:150?ST-3?,the transmittance of the films was the highest and the peak transmittance was about 85%.The surface particle size is between 16 nm and 18 nm,the thickness of the film is about 480 nm,the water contact angle of the film is 5.5°,showing the super-hydrophilicity.So the Si O₂/TiO₂ films have the self-cleaning function.?4?On the basis of high hardness SiO₂ antireflective film prepared by acid catalysis,added organic solvents polyethylene glycol?PEG1000/PEG2000/PEG4000?,polyvinyl pyrrolidone?PVP?.The maximum transmittance of SiO₂ film modified by PVP is about 87%,while the maximum transmittance of PEG modified SiO₂ film is about 90%,and PEG1000 modified SiO₂ film transmittance is best,the maximum transmittance reached 91%.PEG2000,PEG4000 modified film hardness between 2H and 3H,while the hardness of PEG1000 modified SiO₂ film about 4H,anti-scratch strong ability;The surface of PVP modified films is similar to PEG2000 and PEG4000 modified films,but the hardness is only about 2H,and the scratch resistance is weak.PVP modified SiO₂ antireflective film contact angle is 15°,which is similar to uncoated photovoltaic glass contact angle,did not show significant hydrophobicity,so do not have a clear self-cleaning effect;PEG modified SiO₂ antireflection film of the contact angle are more than 90°,and the water contact angle of PEG1000 modified antireflective film is about 95°,which is a kind of high transmittance,high strength hydrophobic self-cleaning antireflective film.