Synthesis based structural and optical behavior of anatase TiO2 nanoparticles

The effect of synthesis method on optical and photoconducting properties of titanium dioxide (TiO2) nanoparticles has been investigated. Sol–gel and co-precipitation methods have been employed to prepare pure anatase phased TiO2 nanoparticles calcinated at different temperatures below 500 °C. The optimized value of average crystallite size is within the range of 19−21 nm for a common calcination temperature of 400 °C for both the methods. The redshift in optical band gap of 0.9 eV has been observed for the sample synthesized by co-precipitation method with respect to the sol–gel method. The photoluminescence spectrum exhibits broad visible emission in both routes of synthesis while photoconductivity shows fast growth and decay of photocurrent in TiO2 prepared by co-precipitation method as compared to TiO2 prepared by the sol–gel method under visible illumination. Crystal structure based Rietveld refinement of X-ray diffraction data, scanning electron microscopy as well as photoluminescence and photoconductivity measurements were performed to characterize nanocrystalline anatase TiO2.