Optical Properties of LiIn(1-x)Tm_x (WO_4)_2 Blue Phosphor

摘要

LiIn_(1-x)Tm_x(WO_4)_2 (x = 0, 0.5, 1, 5, and 10 at.%) polycrystalline powders blue phosphors were prepared via the classical solid-state reaction method. X-ray diffraction (XRD), scanning electron microscope (SEM), photoluminescence excitation, and emission spectra were used to characterize LiIn_(1-x)Tm_x(WO_4)_2 phosphors. By analyzing the excitation and emission spectra of LiIn_(1-x)Tm_x(WO_4)_2 samples, the result indicates that there exists the energy transfer only from the WO_4~(2-) group to the ~1G_4 energy level of Tm~(3+) ion. On the other hand, the influence of the thulium concentration on the blue emission transition ~1D_2→~3F_4 and ~1G_4 →~3H_6 and the emission of WO_4~(2-) group are investigated.