Zinc-Doping Trap Engineering and FRET Synergy Enable Multicolor Room-Temperature Phosphorescence in Rice-Derived...

The development of multicolor room-temperature phosphorescence (RTP) materials with tunable afterglow is crucial for advanced information encryption. Herein, we propose a synergistic strategy that integrates trap engineering and Förster resonance energy transfer (FRET) process for dynamically adjusting the emission color and lifetime. Expired rice-derived carbon dots@Zn-doping alumina (CDs@Zn_xAl₂O₃) composites with standout RTP properties are designed and fabricated using an in situ preparation strategy. In situ Zn²⁺ doping is employed to engineer trap states within amorphous Al₂O₃, which not only optimizes the energy level structure of confined CDs but also enables precise modulation of phosphorescence color and lifetime. The optimized CDs@Zn_1.5%Al₂O₃ composite achieves an ultralong green RTP duration of up to 22 s. Furthermore, by introducing newly synthesized red-emissive TPA-β-CD-aggregates with excellent aggregation-induced emission (AIE) performance as an energy acceptor, efficient singlet-to-singlet and triplet-to-singlet FRET (SS-FRET/TS-FRET) pathways are established. Tuning the doping ratio allows dynamic control over the competition between these pathways, resulting in finely adjustable multicolor RTP emissions. This work demonstrates a versatile platform for creating color-tunable, ultralong RTP materials and showcases their direct application in time-gated, multilevel security encryption.