Structural investigation and photoluminescent properties of ZnWO4:Dy3+ nanocrystals

In this study, ZnWO4:Dy3+ nanocrystals containing 0.5, 1, and 2 mol% of Dy3+ were synthesized by a coprecipitation method and grown in a microwave-assisted hydrothermal system at 140 °C for 1 h. X-ray diffraction, Rietveld refinement, and Fourier transform Raman and infrared spectroscopy analyses indicated that each of the crystals had a wolframite-type monoclinic structure, with no other phases present. Structural refinement was carried out to model the distorted octahedral [ZnO6], [DyO6], and [WO6] clusters. Furthermore, transmission scanning electron microscopy images revealed interesting crystal morphologies and a decrease of the average crystal size, which were dependent on the Dy3+ doping concentration. Ultraviolet–Visible diffuse reflectance spectra indicated that the optical band gap increases with increasing replacement of Zn2+ by Dy3+ ions. The photoluminescent properties, chromaticity coordinates, and lifetimes of the ZnWO4:Dy3+ nanocrystals were studied.