Synthesis, characterization and optical activity of RE-doped ZnWO4 nanorods and nanospheres by hydrothermal method

Abstract

This work has investigated the effect of different dopants on structure, morphology and optical property of ZnWO4. Rare-earth doped ZnWO4 (ZnWO4:RE, with 0.5, 1, and 2 mol% of Eu3+ and Pr3+) were successfully synthesized by coprecipitation method followed by microwave-assisted hydrothermal system at 140 °C for 1 h. XRD indicated that the crystals have a wolframite-type monoclinic structure and with the addition of dopants the crystallite size decreased. HR-TEM images revealed interesting homogenous nanorods for pure ZnWO4 crystals with grow along (021) direction. For ZnWO4: RE we have found nanospheres morphologies, in which the decreasing crystal size were dependent on the RE doping concentration. IR spectra confirm the crystals structure. Ultraviolet–Visible diffuse reflectance spectra indicated that the optical band gap varies with increasing replacement of Zn2+ by RE ions. Egap was characteristic of semiconductor materials.