Carbon Dot Composites Exhibiting Time-Dependent Phosphorescence Color and Circularly Polarized Room-Temperature Phosphorescence

Time-dependent phosphorescence color (TDPC) materials offer a temporal dimension for information encryption, but integrating circularly polarized luminescence (CPL) into TDPC systems to achieve circularly polarized room-temperature phosphorescence (CPRTP) remains challenging. Herein, we obtain three carbon dot-based composites (RG-CDs, GB-CDs, and YG-CDs) that simultaneously exhibit TDPC and CPRTP via pyrolysis of boric acid, arginine, and selected organic dyes. After turning off a 365 nm UV lamp, RG-CDs change from red to green, GB-CDs from green to blue, and YG-CDs from yellow to green. Time-resolved phosphorescence spectra and lifetime measurements confirm that these dynamic behaviors originate from multiple emissive centers with distinct decay rates. Leveraging the synergy of TDPC and CPRTP, we demonstrate multilevel anticounterfeiting and dynamic information encryption. This work establishes a promising platform for designing carbon dot-based chiroptical systems with time-dependent optical signatures.