Optical temperature sensing behavior of aluminum sheet fused with CaSrSiO4:Yb3+, Er3+ phosphor

In this work, Al–CaSrSiO4:Yb3+,Er3+ temperature sensing materials were prepared by the high-temperature solid-phase reaction method, and the upconversion photoluminescence characteristics and optical temperature sensing properties were measured and discussed. Two intense green emissions were observed under the excitation of 980 nm semiconductor laser. The temperature sensing performance of the thermally coupled energy levels was evaluated based on the fluorescence intensity ratio technique in the temperature range from 303 to 723 K, and the maximum sensor sensitivity of the synthesized sample reaches 0.0059 K−1 at 453 K. Furthermore, the relationships between the absolute sensitivity SA and temperature T as well as between SA and energy gap ΔE are analyzed in depth. And then, a strategy to quickly match the temperature measurement range to a suitable temperature sensing material was proposed, and the as-prepared Al–CaSrSiO4:Yb3+,Er3+ sample was determined to be suitable for measuring the high-temperature environment. These observations suggest that Al–CaSrSiO4:Yb3+,Er3+ samples have promising applications for non-contact optical temperature measurement at high temperature and high sensitivity.