Upconversion Luminescence and Temperature Characteristics of GdNbO_4∶Er~(3+)/Yb~(3+) Phosphors
WU Zhong-li;WU Hong-mei;YAO Zhen;TANG Li-dan;DAI Xiao-chun;GUO Yu;Faculty of Mechanical Engineering and Automation,Liaoning University of Technology;School of Chemical and Environmental Engineering,Liaoning University of Technology;College of Science,Liaoning University of Technology;
A series of Er~(3+)/Yb~(3+)co-doped phosphors with various Er~(3+)concentrations were synthesized via the conventional high temperature solid state method. The crystal structure of the obtained phosphor was analyzed by means of X-ray diffraction( XRD). The results show that the doping concentration do not evoke the change in crystal structure. The upconversion emission spectra for the phosphors doped with various Er~(3+)concentrations were measured upon 980 nm excitation under the same experimental conditions. The results show that the concentration quenching occurs at a higher concentration. The optical temperature sensing properties based on the fluorescence intensity ratio( FIR) method were discussed by analyzing intensities ratio of ~2H_(11/2) and ~4S_(3/2) emission with the temperature. It is observed that the sensitivity increases first and then decreases with the increase of temperature,and the sensitivity is the highest at 180 ℃. A physical model involving radiative/nonradiative transitions and thermal excitation of ~2H_(11/2) and ~4S_(3/2) emission is established,and the temperature quenching of the phenomenon is explained successfully.