Thermally recovered mechanoluminescence in Ca₆BaP₄O₁₇:Eu²

Stable reproducibility of mechanoluminescence (ML) is of vital importance for trap-controlled ML materials. Photo/electric excitation is usually needed for ML recovery of trap-controlled materials. In this work, it is demonstrated that thermal treatment can be applied to achieve recovery of ML, which is ascribed to the unique trap level configuration. The Ca₆BaP₄O₁₇:Eu²⁺ performing robust trap-controlled ML has been proposed, and the corresponding repetitive ML can be realized by thermal treatment. TL spectra reveal that the thermally induced reproducible ML benefits from the dual defect level electronic structure of Ca₆BaP₄O₁₇:Eu²⁺. The ML intensity is dependent on the electrons in shallow traps, and the electron transfer from deep traps to shallow traps induced by thermal treatment leads to repetitive ML.