Effect of vanadium and tungsten doping on the structural, optical, and electronic characteristics of TiO<inf>2</inf> nanoparticles

Abstract

Nanoparticles of TiO2 and Ti0.97M0.03O2 (M≡V, W) samples were produced using sol–gel procedure. Utilizing synchrotron x-ray diffraction data, Rietveld refinement confirmed incorporation of V and W into TiO2 lattice forming a single anatase phase. The effect of doping on the cell parameters, Ti octahedral bond length and its distortion index, crystallite size and microstrain was studied. Also, the changes in the UV–Vis and photoluminescence spectra (color and intensity) were investigated. In the visible range, V-doped sample displayed the highest absorption. The direct optical band gap TiO2, V-, or W-doped TiO2 are 3.1 eV, 2.35 eV, and 2.25 eV, respectively. The density functional calculation (DFT) exhibited a semiconductor nature for undoped and doped TiO2 with V samples, while the W-doped TiO2 sample manifested a metallic characteristic. The effect of doping on the absorption, dielectric function, refractive index, extinction coefficient, and optical conductivity of TiO2 sample was explored using DFT calculation. The maximum value of the refractive index in the case of TiO2 occurred in the UV range, while the doped samples have maximum refractive index values in the visible range.