Luminescence-Based Thermal History Sensing in Rare-Earth-Doped YAG-Based Materials

Rare-earth-ion-doped YAG-based phosphors are promising materials for optical thermal history sensing due to their thermal stability and luminescent properties [1]. In this work, the influence of phase composition on the luminescence of Pr³⁺-, Eu³⁺-, and Er³⁺-doped YAG powders was investigated.

The samples were synthesized by the solid-state reaction method and annealed between 1100°C and 1600°C. Annealing below 1600°C produced powders containing the intermediate YAM and YAP phases, identified by X-ray diffraction (XRD) [2]. Emission and excitation spectra, together with luminescence decay times, were measured for all samples. Phase composition significantly influenced spectral positions, relative emission intensities, and decay times through changes in the local crystal field surrounding the rare-earth ions [3]. These parameters correlated with annealing temperature, while Pr³⁺, Eu³⁺, and Er³⁺ ions exhibited different sensitivities to thermal treatment. The combined analysis of emission spectra and luminescence decay times enables reliable determination of the thermal history of the investigated materials.