Fabrication and Luminescent properties of ZnWO4:Eu3+, Dy3+ white light-emitting phosphors

ZnWO4:Eu3+,Dy3+ white light-emitting phosphors were prepared by a hydrothermal method followed with calcination process. The as-synthesized phosphors were characterized by X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectrum, Raman spectra, scanning electron microscope (SEM), transmission electron microscope (TEM), diffused reflectance spectra, photoluminescence excitation and emission spectra, and photoluminescence decay curves. Furthermore, external quantum efficiency of ZnWO4:Eu3+,Dy3+ was determined. The results showed that the obtained phosphors have monoclinic wolframite structure. The particles of the phosphors was nearly spherical in shape, and the particle size was about 70-100 nm. Upon excitation at UV light, the white light-emitting can be obtained by combining the blue-green emission of tungstate group and characteristic emission of Eu3+ and Dy3+. Based on the excitation/emission spectra and decay curves, the energy transfer and photoluminescence mechanism for ZnWO4:Eu3+, Dy3+ system were discussed.