Yellow Room Temperature Phosphorescence of Carbon Dots for Applications in Information Encryption and Anticounterfeiting

Room temperature phosphorescence (RTP) materials have extensive applications in various fields owing to persistent luminescence and excellent signal-to-noise ratio performance. Nevertheless, the realization of long-lived RTP materials remains challenging due to the spin-prohibited character of the triplet exciton transition. In this study, the bright yellow phosphorescence carbon dot-based composites imbedded in a B2O3 matrix (CDs@B2O3) have been synthesized, and the lifetimes of up to 1.107 s were achieved (naked-eye-detectable persistence lasting over 11 s). XRD, TEM, FT-IR, and XPS analyses were undertaken, and structural analyses reveal that covalent bonds and the confinement effect of the rigid boric oxide matrix effectively constrain the rotation and vibration of CDs' light-emitting groups and suppress nonradiative recombination of triplet excitons. In addition, applications of CDs in fingerprint detection, anticounterfeiting, and information encryption are explored. The research offers fresh perspectives into the development of ultralong afterglow materials for diverse applications.