As expected, the relative concentrations of cellulose, hemicellulose and lignin in the B-fibers were different from those of the precursor bamboo. Such components contributed to the different RTP behavior. XPS analysis showed that the C-O ratio was higher and oxygenincorporated moieties increased by converting bamboo into B-fibers, given the oxidative process (Supplementary Fig. ) . Additionally, B-fibers presented C-O, C=O and O-C-O structures, less evident in the natural bamboo. Such moieties tend to form emissive clusters and enhanced spin-orbit coupling (SOC), favoring RTP emission (Fig. ). FT-IR also confirmed these observations: the intensity of hydroxyl signals in B-fibers was stronger than in natural bamboo. Moreover, the FT-IR signals of hydroxyl moieties in B-fibers shifted to 3360 cm -1 while the signal of bamboo was at 3413 cm -1 , suggesting that a stronger hydrogen bonding take place in B-fibers compared to natural bamboo , stabilizing the triplet excitons and preventing the diffusion of oxygen and humidity (Fig. ). Additionally, XRD spectra suggested that B-fibers formed more crystallized cellulose structures compared to natural bamboo, providing a better environment for RTP emission (Fig. ). Overall, the increased oxygen-incorporated moieties, hydrogen bonding and crystallinity cooperatively contributed to the enhanced RTP of the B-fibers.