Effect of Reaction Time on Structure, Morphology and Optical Energy Gap of TiO2 Nanorods Prepared by One-Step Hydrothermal Method

Abstract

Abstract: In this study, well-aligned rutile TiO₂ nanorod arrays were grown on fluorine-doped tin oxide (FTO) substrates by a hydrothermal technique using TiCl₄ as the titania precursor. The influence of hydrothermal reaction (growth) time on the change of nanostructure shape and size during the preparation of the nanorods was examined. The study investigated the characteristics of the prepared TiO₂ nanorods using various analytical techniques, such as X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Raman spectroscopy, and UV-visible spectrophotometer. Diverse structures, morphologies, and optical band gaps of TiO₂ nanorods were obtained by varying the hydrothermal reaction time at optimized growth factors such as growth temperature, precursor concentration, and acidity. The composition remained rutile, although the particle size and the average diameter of the nanorods changed with the growth time. It was observed that the absorption edge shifted to longer wavelengths (redshift), and the predicted band gap of TiO2 decreased as the growth time increased. Additionally, the rutile phase was confirmed through Raman spectroscopic analysis.

Keywords: TiO₂, FTO, One-step Hydrothermal, Growth time, Nanorods.