Preparation of SiO2 anti-reflection coatings by sol-gel method

Antireflection coating for photovoltaic glass is very important for enhancing its optical transmittance, and ensuring a high light absorption and efficiency of PV modules. In this paper, a SiO2 coating with an excellent antireflection effect was realised with the sol-gel method, which is low cost and easily controlled. In our experiments, a silica (SiO2) sol was prepared by a sol-gel process and then the SiO2 coating was deposited on clean glass substrates by dip coating. The coatings were then annealed at 450°C for 1 hour to increase the quality. Using an optimized type of catalyst and film thickness, the optical transmittance of the coated soda-lime glass could be increased by more than 5%. In addition, the influence of a catalyst (PF127) on the refractive index of the coating was evaluated. The experimental results showed that catalyst PF127 and a suitable heat treatment generate pores in the film which reduce the refractive index. The optimized single-layer SiO2 coatings on soda-lime glass substrates exhibited an average transmittance of 95% in the 300 to 1300 nm wavelength range.