VUV–UV–vis Luminescence, Energy Transfer Dynamics, and Potential Applications of Ce³⁺- and Eu²⁺-Doped CaMgSi₂O₆

Ce³⁺ and Eu²⁺ single- and double-doped CaMgSi₂O₆ phosphors have been prepared by a high-temperature solid-state reaction approach. The VUV–UV–vis luminescence properties are investigated at cryogenic temperatures. The dependencies of luminescence intensity and lifetime on temperature are discussed in detail, and the different thermal-quenching characteristics of luminescence of Ce³⁺ and Eu²⁺ in CaMgSi₂O₆ are revealed combined with the VRBE scheme. Because of the different energy barriers of the lowest 5d energy and the conduction band bottom, luminescence thermal quenching of Ce³⁺ does not occur below about 505 K, but that of Eu²⁺ arises at a temperature above ∼300 K. The energy transfer dynamics is then analyzed by using the Inokuti-Hirayama, Yokota-Tanimoto, and Burshtein models, respectively. The Ce³⁺–Eu²⁺ energy transfer is mainly through the electric dipole–dipole interaction with a critical distance of about 21.2 A, and the energy migration between Ce³⁺ ions in a fast or slow way is negligible. The different thermal-quenching behaviors of Ce³⁺ and Eu²⁺ luminescence and their energy transfer pave the way for the potential applications of the codoped samples in optical thermometry and anticounterfeiting.