To understand the interaction between the components, DFT calculations were performed assuming polysaccharide chains and single aromatic ring as model structures for cellulose/hemicellulose and lignin. The simulation results showed that polysaccharides tended to form strong hydrogen bonds (Fig. ). They also interacted with lignin via hydrogen bonding and van der Waals interactions (Fig. ). These results indicate that lignin was confined by the cellulose/hemicellulose in bamboo and B-fibers. Also, hydroxyl moieties of cellulose/hemicellulose formed molecular clusters. Molecular confinement and clusters promoted radiative migration of triplet excitons and RTP emission.