Tunable morphology with selective faceted growth of visible light active TiO₂ thin films by facile hydrothermal method: structural, optical and photocatalytic properties

Selective faceted growth of highly ordered TiO₂ (002) nanorods were coated over fluorine doped tin oxide (FTO) substrate prepared by facile and cost effective hydrothermal method for different reaction temperatures (100, 120, 140 and 160 °C). The rutile phase TiO₂ and highly preferential oriented along (002) plane were confirmed from the XRD pattern. The TiO₂ thin film, prepared with different reaction temperature consisting of anisotropic structures was analysed by SEM and the elemental composition of the films was identified using EDAX. The optical band gap of the TiO₂ thin films was found to be 3.5–3.1 eV using UV–visible spectroscopy. The presence of rutile TiO₂ phase was confirmed from raman analysis. As a result of photoluminescence studies, improvement of charge separation with low recombination rate was observed in TiO₂ thin films. The anionic (Congo Red, Direct Red) and cationic (Rhodamine B and Malachite Green) dye decolorisation of the TiO₂ thin films was investigated under visible light from photocatalytic activity.