Yellow upconversion luminescence in Ho~(3+)/Yb~(3+) co-doped La_2(WO_4)_3 Phosphor

摘要

The strong yellow upconversion(UC) light emission has been observed in Ho~(3+)/Yb~(3+) co-doped La_2(WO_4)_3 phosphor under the excitation of 980 nm diode laser. The phosphors were synthesized by the traditional solid-state reaction method. The phrase structures of the samples were characterized by X-ray diffraction (XRD). The doping concentration of Yb~(3+) was determined to be 20mol% for the strongest yellow emission. Then, the dependence of UC emission intensity on excitation power density showed that the green and red UC emissions are involved in two-photon process. The possible UC mechanisms for the strong yellow emission were also investigated.