Morpho-structural and opto-electrical properties of chemically tuned nanostructured TiO2

Abstract

Titanium dioxide (TiO2) nanoparticles were synthesized by co-precipitation and sol-gel techniques. Effects of synthesis techniques on crystallographic structure, surface morphology, optical and electrical properties were extensively investigated. Rietveld refinement analysis of X-ray diffraction (XRD) spectra was performed by considering pure anatase phase having I41/amd space group of the tetragonal structure of TiO2 and various refinement/ crystallographic parameters were calculated. This pure anatase phase for samples synthesized by both of the techniques was further confirmed by Raman spectra analysis. Metal oxide functional group and residual species were identified by Fourier transform infrared (FTIR) spectra for both samples. The effect of synthesis techniques on the development of microstructure and morphology of the TiO2 nanoparticles was observed in scanning electron microscopy (SEM). Optical properties revealed the redshift of 0.18(5) eV and 0.10(3) eV with respect to bulk anatase TiO2 for the co-precipitation and sol-gel derived samples respectively. A lower dielectric constant and larger conductivity of the sample synthesized by co-precipitation technique attributed to the lower crystallite size and band gap energy.