Preparation of thin silica films with controlled thickness and tunable refractive index

摘要

A method of forming a porous silica film includes the following steps: a) providing a substrate; b) coating, on a surface of the substrate, a layer of charged polyelectrolyte; and c) applying an aged silica-bearing non-colloidal solution to the coated surface of the substrate to adsorb porous silica thereon. The adsorption cycle of steps (b) and (c) is repeated a number of times to control film thickness. The age and concentration of the silica-bearing solution are selected to control the porosity and the index of refraction of the porous silica film.