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Preparation and Characterization of Porous Silica Antireflective Thin Film on Glass Substrates by Chemical Etching

In this paper, porous silica antireflective thin film with special nanostructure has been successfully established using glass-cover board as a single precursor through a novel chemical etching route. The process mainly involves selective leaching of active component on the surface of glass such as sodium oxide, calcium oxide. The effects of etching time, acid concentration and temperature on the porous silica antireflective thin film were demonstrated. Surface microstructure and optical properties of the porous silica antireflective thin film were characterized in detail by scanning electron microscopy (SEM), UV-visible (UV-Vis) spectroscopy. The results indicate the porous silica antireflective thin film were composed of granular with diameter less than 30nm, and the thickness of film was in the range of 80~100nm. Enhanced transparency (up to 94.6%) was achieved in a wide wavelength range.