White light-emitting Ba0.05Sr0.95WO4:Tm3+Dy3+phosphors

Tm3+and Dy3+co-doped Ba0.05Sr0.95WO4phosphors were synthesized by a low temperature combustion method. The structures of the samples were SrWO4phase and were identified by X-ray diffraction. The surface topographies of Ba0.05Sr0.91WO4:0.01 Tm3+0.03 Dy3+were tested by scanning electron microscopy. The particles are ellipsoid, and their average diameter is approximately 0.5 μm. The emission spectra of Ba0.05Sr0.95WO4:Tm3+show a peak at 454 nm which belongs to the3H6→1D2transition of Tm3+, and the optimum doping concentration of Tm3+ions was 0.01. The emission spectra of Ba0.05Sr0.95WO4:Dy3+consist of the4F9/2→6H13/2dominant transition located at 573 nm, the weaker4F(9/2→6H15/2transition located at 478 and 485 nm. and the weakest4F9/2→6H11/2transition located at660 nm, and the optimum doping concentration of Dy3+ions was 0.05. A white light is achieved from Tm3+and Dy3+co-doped Ba0.05Sr0.95MoO4crystals excited at 352-366 nm. With the doping concentration of Tm3+fixed at 0.01, the luminescence of Ba0.05Sr0.95MoO4:Tm3+Dy3+is closest to standard white-light emissions when the concentration of Dy3+is 0.03; the chromaticity coordinates are(0.321,0.347), and the color temperature is 6000 K.