# Achieving Photo‐Activated Circularly Polarized Room Temperature Phosphorescence from Natural Biopolymers

## TL;DR

This paper introduces a sustainable, biopolymer-based material that exhibits photo-activated circularly polarized room temperature phosphorescence with tunable properties for optoelectronic applications.

## Contribution

The first example of a bio-based photo-activated CPRTP material using arylboronic acids in a hydroxypropyl cellulose matrix.

## Key findings

- The material achieves high dissymmetry factors (g lum up to -0.43) and prolonged phosphorescence lifetimes.
- Dynamic switchable CPRTP with opposite handedness is achieved by controlling drying kinetics.
- Responsive on/off CPRTP is demonstrated under water/heat stimuli for encryption and ink applications.

## Abstract

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 (gl
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.

This bio‐based chiral luminescent system exhibit photo‐activated CPRTP by anchoring arylboronic acids to hydroxypropyl cellulose (HPC) matrix. Notably, by controlling the drying kinetics, dynamic switchable CPRTP with opposite handedness can be obtained due to a balance of photonic bandgap (PBG) effect and chirality transfer effect induced by the HPC photonic structures. Leveraging the abundant and responsive CPRTP features, light‐controlled information storage, encryption tags, and multimode afterglow inks are well showcased.