Electron structure of TiO₂ composite films with noble metal nanoparticles

Abstract

Thin nanocrystalline films of ТіО₂, TiO₂/ZrO₂, TiO₂/ZrO₂/SiO₂, TiO₂/ZrO₂/SiO₂/Ag and TiO₂/ZrO₂/SiO₂/Au were prepared using the sol-gel synthesis method. In this paper, we determined the bandgap for direct and indirect band-to-band transitions. Optical conductivity of the films was determined using the spectral ellipsometry method. Depending on the nanocomposite composition, optical conductivity is of different character due to light absorption caused by the presence of the structure intrinsic defects: oxygen vacancies (F²⁺, F, and F⁺ centers), Ti³⁺ ions and interstitial Ti atoms. Rearrangement of the electron spectrum in these thin films due to the aforementioned defects can improve photocatalytic activity in the UV and visible spectral ranges.