Low temperature preparation of high refractive index and mechanically resistant sol-gel TiO2 films for multilayer antireflective coating applications

TiO2 sol-gel thin films have attracted a large attention for applications w hich require high refractive index transparent layers. In this work, sol-ge l TiO2 layers were prepared by Aerosol-gel deposition followed by a thermal treatment procedure in air. Depending on the experimental conditions, abra sion resistant and high refractive index layers could be obtained after pos t-treatment at only 110 degreesC. In this paper, the experimental parameter s which allow the preparation of functional TiO2 sol-gel layers at such low temperature are discussed. It is concluded that the preparation of high re fractive index and mechanically resistant TiO2 layers can be interpreted in terms of competition between polycondensation and densification mechanisms . This result allows to envisage the sol-gel processing at low temperature of multilayer antireflective coatings.