Ultra-stable and long-lived multi-color room temperature phosphorescent carbon dot and silica composites for data encryption and anti-counterfeiting

Carbon dot (CD)-based room temperature phosphorescence (RTP) materials have garnered fundamental attention due to their unique and irreplaceable advantages. However, developing CD-based materials with stable multi-color RTP emission is also desired. Herein, we present a rational design of carbon dots and SiO2 composite (CD@ Silica) fabrication, which demonstrates excellent stability in its RTP, showcases multi-color emission, and experiences thermal enhancement. Multi-color afterglow emission is achieved in CD/fluorescence dyes@ Silica composite systems due to the high efficiency of the Förster resonant energy transfer (FRET) processes between CDs and fluorescence dyes. The covalent interactions between CDs and silica shells protect the triplet state, and the structure significantly promotes the multi-color RTP emission realized in some challenging environments (such as in acid or alkaline aqueous solution). Utilizing the stable phosphorescence emission, we successfully implement the concepts of multi-level information encryption and fingerprint anti-counterfeiting through CD@ Silica composites.