Optical thermometry of Tm3+/Yb3+ Co-doped Ba3Gd2F12 up-conversion glass-ceramic with high sensitivity

In this work, Tm3+/Yb3+ co-doped Ba3Gd2F12 oxyfluoride glass-ceramic was synthesized by the conventional melt-quenching method, and an optical thermometer with high sensitivity was proposed accordingly. The structural and optical properties of Ba3Gd2F12: Tm3+/Yb3+ glass-ceramics were systematically investigated. After crystallization, the enrichment of Tm3+ ions in the Ba3Gd2F12 lattice leads to enhancing emission intensity, the prolonged lifetime of Tm3+ ions, and Stark splitting of emission spectra. The dependence of optical properties of Ba3Gd2F12: Tm3+ glass-ceramics on temperature were explored based on fluorescence intensity ratio of 3F2,3 ​→ ​3H6 and 1G4→3F4 transitions of Tm3+ ions. The maximum value of relative sensitivity SR reaches 1.02% K−1 at 457 ​K. This work indicates that the oxyfluoride glass-ceramic embedded with Ba3Gd2F12: Tm3+/Yb3+ nanoparticles is a candidate material with good performance for optical temperature sensors.