Structural, Optical and Photocatalytic Properties of Ba-Doped TiO₂ Thin Films

Ba-doped TiO2 thin films were deposited onto glass substrates by sol-gel spin-coating method and annealed at 550 degrees C for 2 h. The effect of barium doping on the structural, morphological, optical, and photocatalytic properties of TiO2 thin films was investigated. X-ray diffraction analysis revealed that all films crystallize in the anatase phase with the plane (101) as preferential orientation. As a result of the Ba doping, the crystallite size decreased from 19 to 9 nm. The surface morphology and roughness of TiO2 were shown to be affected by Ba doping content using atomic force microscopy. As Ba content increased, the optical transmittance of the films increased to over 85% in the visible region and the gap energy increased from 3.42 to 3.77 eV. Doping by barium enhances the photocatalytic activity of TiO2 film for degradation of rhodamine B under UV light irradiation, and the best performance was found for 3% of Ba:TiO2 film.