Sustainable Room Temperature Phosphorescence From Carbon Dots Confined in a Cellulose-Rich Coconut Coir Matrix

Room temperature phosphorescence (RTP) materials derived from sustainable resources are highly desirable but remain challenging due to the intrinsic instability of triplet excitons under ambient conditions. Herein, a biobased RTP system is reported by selectively integrating chlorogenic acid-derived carbon dots (CDs) into a cellulose-rich coconut coir matrix. The coir fiber, after oxidative delignification, forms a rigid and dense hydrogen bond network that effectively confines the emissive CDs and suppresses non-radiative decay. The incorporation of CDs not only introduces tunable emissive states but also enables stable phosphorescence through synergistic interactions with the matrix, achieving lifetimes up to 529.07 ms under ambient conditions. The phosphorescence color can be continuously tuned from green to orange-yellow by varying the precursor composition, while excitation-dependent afterglow further enables multicolor phosphorescence from a single material. Furthermore, the materials exhibit excellent processability and can be fabricated into films, fibers, powders, and sponges without loss of RTP properties. This work demonstrates a sustainable strategy for constructing RTP materials using biomass-derived cellulose as a structural scaffold, offering a promising pathway for high-value utilization of agricultural waste in anti-counterfeiting and information encryption.