Optical and Photocatalytic Properties of Fe3+-Doped Tio2 Thin Films Prepared by a Sol–Gel Dip-Coating

Abstract

The present work focuses on the effect of doping on the synthesis, characterization and photocatalytic activity of TiO₂ thin films doped with iron at different percentages by the sol–gel method and characterized by using techniques such as x-ray diffraction (XRD), scanning electron microscopy (SEM), UV–visible spectroscopy and Fourier transform infrared (FTIR). and photocatalytic degradation of Rhodamine B under the sunlight. The XRD results revealed that the synthesized samples are pure and crystalline in nature and show a tetragonal anatase phase of TiO₂, Moreover, also revealed that the crystallinity and crystal size increasing with increasing Fe³⁺ percentage due to the aggravation of anatase TiO₂ crystallinity. SEM microscopic images showed that all the well-adhesive Fe³⁺ Doped TiO₂ thin films had homogeneous and smooth surfaces, contained granular nanocrystals, and without cracks. The UV–vis absorption spectra showed that the absorption of the TiO₂ thin films had a small red-shift as the Fe³⁺ percentage increased. The direct band gap energy (Eg) of Fe³⁺-doped TiO₂ thin films decreased with increasing Fe³⁺-doping . this behavior is attributed to the Fe³⁺, whose presence decrease the band gap and could stabilize the separation between the photogenerated electron-hole pair. Moreover, the rate constant of Rhodamine B decomposition increased as the Fe³⁺ percentage increased. Fe³⁺ doped TiO₂ exhibited enhanced photocatalytic efficiency compared to pristine TiO₂, attributed to improved charge separation and higher electron-hole pair generation.