Temperature-dependent upconversion luminescence and spectra characteristic of Er3+/Yb3+ co-doped fluorotellurite glasses.

Abstract Er3+/Yb3+ co-doped fluorotellurite glasses were prepared. Intense green and red upconversion (UC) emissions corresponding to the transitions of 2H 11/2 , 4S 3/2 →4I 15/2 and 4F 9/2 →4I 15/2 were observed under 980 nm laser excitation, benefiting from the advantages of low phonon energy and good stability of fluorotellurite glasses. Temperature-dependent UC luminescence was carried on glasses with different doping concentration of Er3+ in the range of 298–568 K. Fluorescence intensity ratios (FIR) and absolute sensitivities (S a) were calculated, and the maximal sensitivity value of 54.09 × 10−4 K−1 was obtained at 531 K in the glass with the lowest Er3+ concentration at 0.1 mol%. This study indicates that Er3+/Yb3+ co-doped fluorotellurite glasses can be promising materials applied to non-touching temperature sensors. [ABSTRACT FROM AUTHOR]