Promising Yb3+-sensitized La2Mo2O9 phosphors for multi-color up-conversion luminescence and optical temperature sensing

Abstract

In this paper, a series of Yb3+,Er3+/Tm3+/Ho3+ co-doped La2Mo2O9 with three-primary color up-conversion luminescence are synthesized using the solid state reaction method. The luminescence characteristics and mechanisms of La2Mo2O9:Yb3+,Er3+/Tm3+/Ho3+ phosphors excited by 980 nm are investigated in detail. The increased probability of 5I6→5I7 is an important cause of strong red emission in the Yb3+,Ho3+ co-doped La2Mo2O9. Furthermore, the optical temperature sensing performance are evaluated according to the typical thermally coupled and non-thermally coupled levels of Yb3+,Er3+/Tm3+/Ho3+ co-doped systems. The maximum relative sensitivity and absolute sensitivities are 1.15% K−1 and 10.03 × 10−3 K−1 for La2Mo2O9:Yb3+,Er3+; 2.29% K−1 and 0.284 × 10−3 K−1 for La2Mo2O9:Yb3+,Tm3+; and 0.30% K−1 and 20 × 10−3 K−1 for La2Mo2O9:Yb3+,Ho3+, respectively. The multi-color up-conversion luminescence phosphors with high temperature sensing sensitivities present broad application prospects in the fields of anti-counterfeiting, three-dimensional display, and non-contact temperature sensing.