Template-free sol–gel preparation of antireflection films with adjustable refractive index

Abstract

A antireflection film with adjustable refractive index from 1.17 to 1.41 was prepared at room temperature via a template-free sol–gel method, using tetraethylorthosilicate(TEOS) as co-precursor. In this study, the regulation of the refractive index is achieved by mixing different volumes of acid-catalyzed silica sol having a refractive index of 1.41 with a base-catalyzed silica sol having a refractive index of 1.17. The silica coating, with a refractive index of 1.2332, prepared by this base/acid two step catalysis sol-gel process can increase the transmittance of K9 glass by about 3.5%.