The influence of Zn+2 doping and annealing temperature on grown-up of nanostructures TiO2 thin films prepared by sol-gel dip-coating method and their photocatalytic application

Abstract

Nanostructures of Zn+2-doped TiO2 thin films were prepared by sol gel dip-coating method deposited on silicon substrate, the films were heated at temperature from 600 °C to 1000 °C for 2 h. The doped thin films were characterized using X-ray diffractrometer (XRD), Raman spectroscopy, FTIR spectroscopy, Scanning electron microscopy (SEM), Atomic force spectroscopy (AFM), Reflectance and Photoluminescence spectroscopy (PL). It was determined that the films crystallize on anatase and ZnTiO3 phase at annealing temperature 600 °C. At high temperature 800 °C, 1000 °C we observed completely transformation of anatase to rutile and ZnTiO3 phase, in addition the Zn2TiO4 phase was taking place. SEM and AFM confirmed the changing morphology with increasing annealing temperature as a progression of nanoprous to nanorods and nanofils structures. Photoluminescence and reflectance results revealed that Zn+2-doped TiO2 thin films have excellent optical properties, which enhance the photocatalytic activity. Following on this, a test photo conversion cell was constructed and cyclic voltammetry was used to study photocurrent response in the dark and under illumination, confirming high conversion efficiency which proved the behavior of the solar cell.