Full‐Color Dynamic Afterglow in Carbon Dot‐Based Materials Regulated by Dual‐Phosphorescence Resonance Energy Transfer

Developing afterglow materials with wide-range and time-dependent colors is highly desirable but challenging. Herein, by calcinating the mixture of Rhodamine B and NH₄Al(OH)₂CO₃, carbon dots (CDs) are generated and in situ embedded in the porous Al₂O₃, forming the CDs@Al₂O₃ composite, which exhibits time-dependent phosphorescence colors (TDPCs) from blue to green after excited by a UV lamp. Photophysical studies reveal that the blue phosphorescence with a short lifetime of 214 ms originates from the carbon core state, while the green phosphorescence with a long lifetime of 915 ms is associated with the surface state of CDs. Simultaneous activation of the blue and green phosphorescence with different lifetimes induces the TDPC performance. Using CDs@Al₂O₃ as the donor, a series of long-wavelength fluorescent dyes including Rhodamine 123, Rhodamine 6G, and Rhodamine B as the acceptors, and epoxy resin (ER) as the matrix, a dual-phosphorescence resonance energy transfer system (CDs@Al₂O₃-dye-ER) is constructed to rationally regulate the afterglow emission, conferring the full-color dynamic afterglow from blue to red at different decay times with high afterglow quantum yields of up to 48.2%. The fascinating afterglow properties of the CDs@Al₂O₃-dye-ER composites enable their successful applications in multidimensional information encryption and polychrome 3D artworks.