Xylan-based full-color room temperature phosphorescence materials enabled by imine chemistry

Developing sustainable matrix and efficient bonding mode for preparing room temperature phosphorescence (RTP) materials with full-color afterglows is attractive but still challenging. Here, xylan, a hemicellulose by-product from the paper mill, is used to construct full-color RTP materials based on imine bonds. Xylan is oxidation by periodate to introduce aldehyde groups to increase reaction sites; aromatic amines with different π conjugations can be readily anchored to dialdehyde xylan (DAX) by imine chemistry. The dual rigid environments were constructed by hydrogen bonding and imine covalent bonding, which can facilitate the triplet population and suppress non-radiative transitions, thus the xylan derivatives display satisfactory RTP performances. As the degree of conjugation of the chromophore increases, the afterglow colors can be changed from blue to green, yellow, and then to red. Thus, such a universal, facile, and eco-friendly strategy can be used to fabricate full-color RTP materials, which show a bright future in information encryption and advanced anti-counterfeiting. These results unambiguously state that the biodegradable paper mill waste-based RTP materials are convincingly expected to replace and surpass petroleum polymer-based counterparts.