Blue upconversion luminescence properties of La_2(WO_4)_3:Yb~(3+)/Tm~(3+) phosphor

摘要

Monoclinic La_2(WO_4)_3 nanophosphors codoped with Tm~(3+) and Yb~(3+) ions were synthesized via hydrothermal process followed by heat treatment. Powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize as-prepared samples. The dependences of Yb~(3+) concentration and laser pumping power on the upconversion emissions were extensively investigated. The results show that upconversion luminescence increases with the Yb~(3+) concentration and gets its peak at 30 %. The upconversion mechanism and process in the Yb~(3+)/Tm~(3+) codoped La_2(WO_4)_3 phosphors were analysed.