Blue-green, red, and white light emission of ZnWO(4)-based phosphors for low-voltage cathodoluminescence applications

ZnWO(4) and ZnWO(4):Eu(3+) particles were prepared by refluxing in water solution using polyethylene glycol as a capping agent and then annealed at different temperatures. The samples were characterized by X-ray diffraction, Raman spectra, field-emission scanning electron microscopy, and cathodoluminescence spectra. The as-prepared amorphous samples annealed at high temperature (500-700 degrees C) are sanmartinite structure of ZnWO(4), and the spherical morphologies are basically retained, except for the increase of the particles size (from 28 to 56 nm). The low-voltage luminescent properties of these tungstate phosphors can be tuned by the doping of Eu(3+) ions and annealing treatment. ZnWO(4) and ZnWO(4):Eu(3+) particles annealed at 500 degrees C or above exhibit strong blue-green and white light emission under the excitation of low-voltage electron beams, respectively, the former originating from the intrinsic WO(6)(6-) complex, and the latter due to the combination of the emissions arising from the intrinsic WO(6)(6-) and doped Eu(3+) ions. The as-prepared ZnWO(4):Eu(3+) particles only emit a red light resulting from the (5)D(0)->(7)F(J) (J = 1, 2, 3, 4) transitions of Eu(3+) ions. (c) 2008 The Electrochemical Society.