Liquid phase deposition of TiO2 on glass: Systematic comparison to films prepared by sol-gel processing

TiO2-coatings were prepared by liquid phase deposition (LPD) and sol-gel processing on glass and calcinated at different temperatures in order to systematically compare prospects and limitations of both techniques. Film thickness, refractive index, light scattering, and pencil hardness were measured as a function of the annealing temperature. The microstructure of the respective films was characterized by scanning electron microscopy and transmission electron microscopy. Results indicate that the mechanical properties of sol-gel coatings are-improved during sintering due to the removal of the organics and crystallization. In contrast to the sol-gel material, TiO2 films deposited by LPD are already partially crystalline after deposition at 50 degrees C from aqueous solution. Calcination, though, leads to the fortnation of:cracks resulting in light scattering. Additionally a decrease in adhesion and pencil hardness is observed.