Upgrading the optical properties of ZnWO4 nanostructure via composing with different contents of ZnS

In order to modify the optical properties of zinc tungstate (ZnWO4), (1-x)ZnWO4/xZnS system was produced using the direct and simple hydrothermal route together with solid state reaction method at low temperature. The structure and microstructure of the formed samples were investigated using synchrotron x-ray diffraction (XRD) technique. XRD, Fourier -transform infrared spectroscopy (FTIR), Raman and photoluminescence (PL) analyses confirmed the formation of single phase (ZnWO4) and incorporation of Zn and S into the ZnWO4 matrix in all samples. The morphology and element analysis of the formed system were explored using scanning electron microscope (SEM) images and the corresponding energy -dispersive X-ray spectroscopy (EDS) analysis. The kubelka- Munk relation was applied to get the optical energy bandgap of the system. (1-x)ZnWO4/xZnS (x = 0, 0.05, 0.1, 0.25) system have the direct optical band gap values of 3.89, 3.25, 3.30 and 3.48 eV, respectively. Numerous empirical formulas were applied to obtain the refractive index of each sample from the estimated optical band gap energy. As the quantity of ZnS increases, the (1-x)ZnWO4/xZnS system's nonlinear optical parameters rise. The effect of ZnS amount on the PL emission spectra of (1-x)ZnWO4/xZnS was studied. The quenching of PL intensity upon composed with ZnS can greatly enhance its functional activity.