Impact of Ti doping and annealing temperature on structural and opto-magnetic properties of tungsten oxide (WO3)

Pure and Ti-doped WO3 nano systems synthesized by the solid state reaction method and annealed at different temperatures, were studied for changes in structural, optical and magnetic properties. X-ray diffraction, Raman, UV-Vis, photoluminescence spectroscopy, vibrating sample magnetometer (VSM) techniques were employed for structural, optical and magnetic characterization to study the modification of the electronic structure and disorder developed in the samples. Inclusion of Ti ions leads to degradation in the crystallinity of the monoclinic single phase system with an increase in the content of the dopant ions, whereas increased annealing temperature enhances crystallinity. A red shift in the optical band gap indicates the production of defect states. As the annealing temperature is raised, the amount of visible photoluminescence (PL) emissions caused by oxygen vacancies decreases. Magnetic experiments demonstrate the ferromagnetic properties of the prepared samples, which exhibit a decrease with Ti doping and an increase in annealing temperature.