Structural and optical studies of TiO2 doped tungsten oxide

The structural and optical properties of pure and TiO2 doped WO3 samples have been analyzed to study the modification of the electronic structure and disorder developed in the samples due to TiO2 doping. The samples are of single phase in nature and no secondary phase or any impurity peak has been detected from structural analysis. The incorporation of Ti ions introduces disorder in the system which leads to slight degradation in crystallinity of the samples with increasing doping. There is decrease in grain size with increase in TiO2 doping concentration. The band gap shows red shift with doping. This is due to the formation of impurity band and trapping of Ti atoms which leads to the generation of the defect states within the forbidden band. Photoluminescence (PL) spectra shows gradual decrease of intensity of blue emission peaks with increasing TiO2 doping. These structural and optical studies manifest increase in defect or disorder in the system with increasing TiO2 doping.