Pumping-route-dependent concentration quenching and temperature effect of green up- and down-conversion luminescence in Er3+/Yb3+ co-doped Gd2(WO4)3 phosphors

Gd-2(WO4)(3) phosphors with various Er3+ concentrations and fixed Yb3+ 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(WO4)(3):Er3+/Yb3+ phosphors were studied, and it was found that the Er3+ doping concentration slightly affected the sensitivity, and Gd-2(WO4)(3):Er3+/Yb3+ 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(WO4)(3):Er3+/Yb3+ sample was decided by both the excitation power and Er3+ doping concentration. (C) 2013 Elsevier Ltd. All rights reserved.