Sustainable Pathways to Flexible and Recyclable Phosphorescent Fibers From Natural Bamboo

A major challenge in sustainable room‐temperature phosphorescent (RTP) materials lies in simultaneously achieving persistent phosphorescence, mechanical robustness, processability, and recyclability within a fully biomass‐derived platform. Here, we develop fully bio‐based RTP fibers (P‐fibers) exclusively from natural bamboo through the bottom‐up reconstruction of bamboo‐derived cellulose (B‐Cell) and lignin (B‐Lig). B‐Cell and B‐Lig were fractionated, dissolved, and wet‐spun into flexible filaments. The resulting P‐fibers exhibit remarkable tensile strength (141 MPa), tunable diameters, and persistent green RTP with a lifetime of 154.09 ms, originating from B‐Lig chromophores stabilized within the B‐Cell matrix. DFT simulations reveal strong intermolecular hydrogen‐bonding interactions between B‐Cell and B‐Lig, which rigidify the microenvironment and suppress non‐radiative decay. Impressively, utilizing a simple dissolve‐and‐re‐wet‐spinning process, the P‐fibers could be efficiently recovered and reprocessed. Remarkably, the regenerated fibers retained their RTP performance, mechanical robustness, and structural integrity through multiple recycling cycles. P‐fibers demonstrated potential applications in anti‐counterfeiting, surgical sutures, and sensing.