Discrete Trap-Enabled Dynamic Multimode Luminescence in Chloro-Apatite Phosphors for Advanced Anticounterfeiting

Developing advanced luminescent materials with multimode emissions is urgently desired for information security but still confronts many challenges. In this work, we achieve multimodal luminescence in a single phosphor by utilizing discrete defect levels, as introduced via chemical substitutions. The cosubstitution of Gd3+–Zr4+ or La3+–Si4+ for Ba2+–P5+ in Ba5(PO4)3Cl:Eu not only modulates luminescence color by tuning Eu2+/3+ coexistence but also introduces discrete electron traps with depths ranging from 0.63 to 1.12 eV. Controllable hexa-mode luminescence is realized, including photoexcited downshifting luminescence (DSL), X-ray excited luminescence (XEL), long-lasting afterglow (LLA), X-ray-charged LLA (X-LLA), thermostimulated luminescence (TSL), and photostimulated luminescence (PSL). The multiresponsive and multicolor luminescent chloro-apatite phosphors show great potential in multilevel anticounterfeiting applications, with excitation wavelength-, time-, and temperature-resolved dynamic displays combining into a spatially distributed image. The multimode luminescence also provides versatile information encryption–decryption technology. This study exploits the possibility of developing advanced materials with multimode luminescence for advanced information anticounterfeiting and encryption applications of high-level security.