Versatile Room-Temperature Phosphorescent Materials from Cellulose

Addressing the imperative of sustainable development, this study demonstrates an eco-friendly luminescent platform integrating high-efficiency room-temperature phosphorescence (RTP) with programmable humidity responsivity. Leveraging carboxymethyl cellulose (CMC) as a matrix, a covalent cross-linked network was constructed through reaction with epichlorohydrin. 4,4',4″-Nitrilotribenzoic acid (NTA) was introduced and confined within the cross-linked network, successfully yielding a multifunctional RTP material. This hierarchical architecture establishes a synergistic rigidification mechanism via covalent-hydrogen-bonding cooperativity, effectively suppressing nonradiative decay pathways while stabilizing triplet excitons. The resultant material achieved outstanding phosphorescent properties with a maximum quantum yield of 44.44% and a maximum phosphorescence lifetime of 231.20 ms. The prepared CMC-based films demonstrate excellent solvent resistance, maintaining stable phosphorescence performance even after immersion in organic solvents. Simultaneously, the material possesses unique humidity-responsive characteristics, enabling reversible information writing and encryption using water as an "ink". Moreover, this material system can be continuously drawn into fibers with distinct RTP properties via wet spinning, achieving morphological expansion from 2D films to one-dimensional fibers. This work provides a promising strategy for developing sustainable, solvent-resistant, and stimulus-responsive RTP materials with excellent processability.