CONTROLLED SYNTHESIS OF THE ZnWO4 NANOSTRUCTURE AND STUDY OF THEIR STRUCTURAL AND OPTICAL PROPERTIES
We investigate the effects of calcination time and concentration of solution on the structure, as well as optical properties in ZnWO4 nanopowder prepared by hydrothermal method. The prepared powder were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman scattering, optical absorption and photoluminescent spectroscopy (PL). It is shown that the grain size and morphology of ZnWO4 nanopowder can be controlled by adjusting the reaction time as well as the concentration of the solution. The resultant sample is a pure phase of ZnWO4 without any impurities. The result showed that the optical property of ZnWO4 nanopowders depend on their grain size. The optical band gap becomes narrower as the reaction time or concentration of solution is increased. The improved PL properties of the ZnWO4 crystallites can be obtained with the optimal concentration of the solution.