BaAl₂O₄:Eu²⁺-Al₂O₃ ceramics for wide range optical temperature sensing

In this paper, BaAl₂O₄:Eu²⁺-Al₂O₃ ceramics were successfully prepared by spark plasma sintering (SPS). The optical properties of the multiphase ceramics doped with different concentrations of alumina were studied. Under excitation with 365 nm ultraviolet light, the luminescent color of the samples can be adjusted by changing the sintering temperature and the contents of alumina addition. The temperature dependent fluorescence spectra in the temperature range of 4 K-434 K were measured, and the temperature dependent fluorescence intensity ratio (FIR) was calculated. The FIR monotonically increased with the increase of temperature, indicating that the material could be used for temperature sensing. The absolute sensitivity S_a of the temperature sensing fluorescent material is larger than 0.005 K^-1 at 334 K-434 K, and the relative sensitivity S_r is larger than 0.75% K^-1 at 304 K-434 K. The results show that the BaAl₂O₄:Eu²⁺-Al₂O₃ ceramic is a promising non-contact temperature sensing material.