Multicolor frequency upconversion luminescence in europium-terbium codoped ytterbium-sensitized fluorogermanate glass excited at 980 nm

摘要

Glass 80GeO_3:10PbF_2:10CdF_2 triply-doped with europium, terbium, and ytterbium phosphors were synthesized and the energy upconversion luminescence emission properties investigated as a function of NIR excitation power, rare-earth ions content combination, and glass phosphor composition. Multicolor visible luminescence with main emissions peaked around 490, 545, 590, 610, 650, and 700 nm was observed when samples were excited by a diode laser at 980 nm. The up-conversion excitation mechanism for both Eu~(3+), and Tb~(3+) excited-states emitting levels was achieved via phonon-assisted cooperative energy-transfer from pairs of excited Yb~(3+) ions. White-light emission with CIE-1931 coordinates in the region of low color correlated temperature was obtained for appropriate combination of rare-earth ions content.