Improved thermally coupled levels based temperature sensing performance by engineering host phonon energy

Luminescence intensity ratio (LIR) based thermometers provide fast response, excellent accuracy and high spatial resolution. Temperature sensitivity is the most critical parameter for evaluating temperature measurement capability, and it is always interesting to develop novel methods to improve its sensitivity. In this work, we verify that the BaF2:Yb/Er NCs with lower phonon energy exhibits better temperature sensitivity than that of CaF2:Yb/Er NCs. The maximum relative temperature sensitivity of CaF2:Yb/Er NCs was calculated to be 0.596% K−1, while that of BaF2:Yb/Er NCs was calculated to be 0.779% K−1. Similar results were also observed through comparing the BaF2:Yb/[email protected]2 and BaF2:Yb/[email protected]2 core/shell NCs. Our results provide a novel method that engineering host phonon energy to improve the thermally coupled levels based temperature sensing performance.