Achieving Photo-Activated Circularly Polarized Room Temperature Phosphorescence from Natural Biopolymers

Developing sustainable photo-activated circularly polarized room temperature phosphorescent (CPRTP) materials is attractive for optoelectronic applications while are difficult to achieve. Here, we report the first example of bio-based photo-activated CPRTP material by anchoring arylboronic acids into hydroxypropyl cellulose (HPC) matrix via B─O covalent bonding. The rigid environment provided by B─O covalent bonds and hydrogen bonds stabilizes the triplet excitons, the residual oxygen is consumed upon continuous UV light irradiation, enabling photo-activated CPRTP with multi-color, high-dissymmetry factor (g_{l um} up to -0.43) and prolonged lifetime from 0.22 ms to 1.57 s. More interestingly, by controlling the drying kinetics, HPC films exhibit tunable and dynamic switchable CPRTP with opposite handedness. In addition, due to the water sensitive phosphorescent nature, HPC films also show a responsive on/off CPRTP under cycled water/heat stimuli treatment. Based on the moldable and responsive CPRTP properties of the HPC based materials, the application of information photo-controlled encrypted tags, wavelength-dependent phosphorescent decorated patterns, multi-mode afterglow inks have been successfully demonstrated. This study offers new insights into the intrinsic chiral luminescence of cellulose macromolecules, providing a sustainable platform for the efficient design and functional application of photo-activated CPRTP materials.