High performance single layer nano-porous antireflection coatings on glass by sol-gel process for solar energy applications

Antireflection coatings have received a great importance due to their ability to enhance the efficiency of the solar cells and solar selective coatings by minimizing the reflections of the incident light from the front surface. In this study, a silica (SiO2) sol, prepared using sol-gel process, was deposited on cleaned glass substrates by dip coating method and subjected to heat treatment at 400 °C. The thickness and porosity of the coating were optimized to achieve high transmittance. The thickness was optimized by varying the lifting speed of the substrate from the sol. The porosity was induced in the coating by using polymeric additives and through heat treatments. The optimized single layer SiO2 coating on cleaned glass substrate exhibited a maximum transmittance of 97.5% at λ=500 nm wavelength. The hybrid sol was found to give reproducible coatings up to a period of 30 days when stored at 16 °C. The present process provides a simple and cost effective method for the preparation of antireflection coatings, which have huge potential to enhance the efficiency of solar cells, receiver tubes and other solar devices.