Pumping-route-dependent concentration quenching and temperature effect of green up- and down-conversion luminescence in Er~(3+)/Yb~(3+) co-doped Gd_2(WO_4)_3 phosphors

摘要

Gd_2(WO_4)_3 phosphors with various Er~(3+) concentrations and fixed Yb~(3+) concentration were synthesized via a co-precipitation method, and their crystal structure and morphology were characterized by using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The concentration quenching behaviors of green up- and down-conversion emissions of Er3* were analyzed, and it was confirmed that the difference between quenching concentration for up- and down-conversion emissions resulted from the different population routes. The temperature sensing properties of the Gd_2(WO_4)_3:Er~(3+)/Yb~(3+) phosphors were studied, and it was found that the Er~(3+) doping concentration slightly affected the sensitivity, and Cd_2(WO_4)_3:Er~(3+)/Yb~(3+) phosphors could be used in a broad temperature region for detecting temperature. Finally, the thermal effect induced by 980 nm LD irradiation was investigated, it was observed that the equilibrium temperature of Gd_2(WO_4)_3:Er~(3+)/Yb~(3+) sample was decided by both the excitation power and Er~(3+) doping concentration.