Optical thermometry based on upconversion luminescence of Ba3Gd2F12: Yb3+/Er3+ nanocrystals embedded in glass ceramics

The traditional melt quenching method was used to successfully prepare transparent glass ceramics (GCs) containing Ba3Gd2F12: Yb3+/Er3+ nanocrystals. The structure and morphology characteristics of the nanocrystals were studied and confirmed by X-ray diffraction, selected-area electron diffraction, and transmission electron microscopy. Under 980 nm excitation, the influence of Er3+ concentration, the heat treatment temperature of the GCs, and the pump power of laser on the upconverted luminescent properties were systematically discussed. GCs have a longer lifetime and higher emission intensity compared to precursor glass. In addition, the temperature dependence of fluorescence intensity ratio based on the thermal coupling energy levels of Er3+ was studied. FIR changes monotonously with temperature, and at 296 K, the relative sensitivity of the GCs sample reaches its maximum value (1.12% K-1). The results show that the GC embedded with Ba3Gd2F12: Yb3+/Er3+ nanocrystals may be a promising candidate for optical temperature sensors.