Sr2GdF7:Tm3+/Yb3+ glass ceramic: A highly sensitive optical thermometer based on FIR technique

In this work, we present a highly sensitive optical thermometer, Tm3+/Yb3+ co-doped Sr2GdF7 transparent oxyfluoride glass ceramic (GC). Sr2GdF7:Tm3+/Yb3+ GC was synthesized by traditional meltquenching method with further crystallization process. Its structural and optical properties were systematically investigated by a series of characterization methods. The enrichment of Tm3+ into Sr2GdF7 lattice is confirmed by enhanced emission intensities, obvious Stark splitting and prolonged lifetimes of Tm3+ after crystallization. Based on fluorescence intensity ratio (FIR) of F-3(3) -> H-3(6) and (1)G(4) -> F-3(4) transitions of Tm3+, the temperature thermometric properties of Sr2GdF7:Tm3+ GC were explored. Interestingly, maximum relative sensitivity SR-max reaches 1.97% K-1 at 353 K and the absolute sensitivity S-A keeps increasing with temperature up to 3.90% K-1 at 563 K. Our investigation demonstrates that Sr2GdF7:Tm3+/Yb3+ GC may act as promising candidate for optical temperature sensor. (C) 2017 Elsevier B.V. All rights reserved.