Influence of cobalt doping on the structural, optical and luminescence properties of sol-gel derived TiO2 nanoparticles

Abstract

We have investigated the structural and optical properties of sol–gel derived cobalt-doped Titanium dioxide (TiO2) nanoparticles. X-ray diffraction patterns exhibit that Co-doped TiO2 forms in anatase phase without any formation of secondary phases. SEM images reveal that the as-grown nanoparticles are almost spherical in size with average particle size in the range of 35–50 nm. Raman spectra recorded at room temperature show that Co doping cancels the rutile phase that was present in the pure TiO2 sample. The energy band gap calculated using UV/Vis spectra and Tauc’s relation is found to be of direct bandgap nature and its value decreases with the doping concentration of cobalt. Our photoluminescence results indicate that a photoluminescence emission is found to be centred around 380 nm in the ultraviolet and around 680 nm in the visible range of spectrum.