Effect of ethylene glycol variation on silica antireflective coatings

A new type of sol-gel process addition of ethylene glycol has been developed. Sol-gel derived bulk and thin films were prepared from different compositions containing varying concentrations of ethylene glycol from 5% to 15% at constant water (H2O)/tetraethyl-orthosilicate (TEOS) ratio. Scanning electronic microscope (SEM) was carried out to monitor the effects of concentration of ethylene glycol on the internal environment of sol-gel materials. Sol-gel thin films, prepared by rotating coating technique were depicted uniform and cracked surface at rotating speed 2,000 r/min (high speed) and 800 r/min (low speed) respectively. It was shown that an antireflective film produced by incorporation of ethylene glycol in the precursor solution is a more effective method to effect the uniformly porous structures of SiO2 thin film on the glass substrate. The surface of the film on glass substrates is seen to exist in different conditions with different compositions of ethylene glycol.