Effect of Yb~(3+) concentration on tunable upconversion luminescence and optically temperature sensing behavior in Gd_2TiO_5:Yb~(3+)/ Er~(3+)phosphors

摘要

The color-tunable upconversion (UC) emission and optical temperature sensing behavior was observed from the Er-Yb codoped Gd2TiO5 (GTO) phosphors synthesized by the simple sol-gel method. By control of the Yb3+ concentration, the phosphors are capable of generating color tunable UC luminescence from yellowish green to yellow, then to orange. The tunable emission is due to the energy back transfer from Er+3 to Yb3+ and the cross relaxation between the two neighboring Er3+ ions. The temperature dependence of the fluorescence intensity ratios (FIR) of two green UC emissions in Gd2TiO5:Yb3+/Er3+ phosphors with different Yb3+ doping concentration have been studied in the range of 298-573 K under 980 nm laser diode excitation and the maximum sensitivities were approximately 40.76 x 10(-4) K-1 at 565 K. The above results suggest that the as-prepared Gd2TiO5:Yb3+/Er3+ phosphors have great potential for the applications of lightings and optical temperature sensors. (C) 2017 Elsevier B.V. All rights reserved.