Experimental investigation on the impacts of annealing temperatures on titanium dioxide nanoparticles structure, size and optical properties synthesized through sol-gel methods

Abstract

Nanoparticles of titanium dioxide (TiO2NPs) have been synthesized and the effects of annealing temperatures have been studied using sol–gel techniques on particle size, optical properties and structures. X-Ray Diffraction (XRD), Raman Spectra, photoluminescence, UV/Visible spectroscopy and scanning electron microscopy (SEM) are used to depict TiO2 nanopowders (PL). From XRD results, nano sized TiO2 (15 nm, 19 nm, 26 nm, & 29 nm) was observed and revealed that pure anatase and routine phase with tetragonal structure were developed. Annealing temperatures gives the transformation of phasesy from anatase to rutine. Particles size, lattice parameters and diffraction intensity of synthesized TiONPs were increased as annealing temperature increases while, full width at half maxima and grain sizes decreased. Uniformly distributed cylindrical shapes of TiO2NPs were observed from SEM images and increases in size with increasing annealing temperatures from 400 °C to 1000 °C. Highly transparent nanopowders are observed in visible region from UV/Visible and red shift towards higher wavelength with increasing annealing temperatures are due to an increment in particle from XRD results and SEM images. The energy band gap of synthesized nanopowders has been reduced with rising annealing temperatures that correspond to the red shift of the optical absorption edge. Raman Spectra has also been characterized by the structural properties of synthesized nanoparticles and demonstrates the existence of anatase and routine tetragonal levels. The overall reduced strength was observed from the results of the PL.