Tunable emission color, energy transfer mechanisms and high thermal stability of Tm3+/Dy3+co-doped single-phase white luminescent tungstate phosphors

Single -phase white phosphors have broad application prospects in phosphor-converted white light emitting diodes. Herein, a series of novel single -phase Tm3+/Dy3+ doped Na5Lu(WO4)4 phosphors were prepared. The detailed investigation of its luminescence behavior showed that Na5Lu(WO4)4:xTm3+,yDy3+ achieved tunable luminescence through the energy transfer process of Tm3+-> Dy3+ at 365 nm excitation. According to the concentration -dependent emission spectra results, the electric dipole-dipole interaction was dominant to be responsible for all the energy transfer processes within the singly- and doubly-doped scenarios. Temperature dependent photoluminescence spectra suggested the excellent thermal stability of Na5Lu(WO4)4:9%Tm3+,5% Dy3+ phosphor, of which the luminescence intensity at 421 K and 471 K was only 13.4% and 18.63% lower than that at room temperature, respectively. Finally, Na5Lu(WO4)4:9%Tm3+,5%Dy3+ phosphor was packaged with a 365 nm near -ultraviolet LED chip, which exhibited bright blue and yellow emission bands at various bias currents. This work suggests that the developed single -phase Na5Lu(WO4)4:Tm3+,Dy3+ phosphors have potential application prospects in the daily lighting field.