Structural and Optical Properties of Ce3+-Doped TiO2 Nanocrystals Prepared by Sol–Gel Precursors

Abstract

Ce-doped TiO2 nanoparticles (NPs) with dopant percentages of 1%, 3%, 5% and 10% were synthesized by the sol–gel method with precursors of tetratitanium isopropoxide and cerium nitrate hexahydrate Ce(NO3)3·6H2O. Based on the x-ray diffraction analysis, it was found that the size of NPs declines with an elevation of Ce impurity; for the pure state of 39 nm and the impure sample of 10%, its value declines up to 9 nm. Furthermore, with the addition of cerium impurity, the tetragonal structure of the TiO2 sample remains unchanged with slight variations in the lattice’s constants. The mean size and shape of the NPs were investigated by the transmission electron microscopy analysis, which were observed to be about 12.5 nm and spherical for NPs with 5% dopant. The results of the diffused reflection spectroscopy optical test showed that the band gap of the prepared samples decreases by 10% with increasing of cerium dopant from 2.75 eV for bare TiO2 NPs up to 2.00 eV for NPs with cerium impurity. In addition, photoluminescence analysis shows the intensity diminishes due to doping, causing a recombination of the electron–hole pair in the Ce-doped TiO2 NPs.