Fabrication of a PVP (Polyvinylpyrrolidone)-assisted TiO2 film using a high-concentrated TiO2 nano sol and its optical properties

Abstract

A PVP (Polyvinylpyrrolidone)-assisted TiO2 film with thickness over 100 nm by one step dip coating was prepared by adding polyvinylpyrrolidone (PVP) to TiO2 nano sol and heat-treatment at the relative low temperature (450°C). The maximum refractive index of PVP-assisted TiO2 film was measured to be 1.8764 after 5th dip coating and heat-treatment in this work. As the amount of TiO2 sol increased, it increased, while it decreased as the quantity of PVP increased. The crystalline phase by X-ray diffraction was identified to be anatase and the intensity increased with film thickness’s increase. The maximum thickness of pure TiO2 film prepared without crack was 1.89 µm and U.V. absorption of PVP–TiO2 nano hybrid film before heat-treatment was measured to be over 98% at 340 nm wavelength.