Effects of ferrous ion doping on the structural, optical, and electronic properties of tin tungstate materials

Metal oxide materials have widespread applications in multiple application fields. On doping Fe³⁺ ions into α – SnWO₄, structural, optical, and electronic properties varied noticeably leading the material into energy storage device applications. Pure and doped SnWO₄ materials were prepared using the solid-state reaction method. Two different phases were observed on doping Fe ions into the host observed through X-ray diffraction. Different functional groups and their vibrations were found using FTIR spectroscopy which deliberately led to the confirmation of the prepared sample's structure. Raman spectroscopy identified different intra and inter-molecular vibrations. Optical energy bandgap was found to be 3.26 eV and 2.78 eV for Pure SnWO₄ and SnWO₄: Fe³⁺ ions respectively. The results obtained from Diffuse reflectance spectra were validated using Density Functional Theory calculations. The theoretical band gap values were found to be close to the experimental value. The optical spectra were also obtained through DFT calculations which were reliable to experimental findings and exciton binding energies were discussed.