Environmentally Friendly and Stimuli-responsive Room Temperature Phosphorescence Nanofiber Membranes Constructed by Bio-fermentation Featuring Versatile Functionality

Stimuli-responsive materials that exhibit ultralong room temperature phosphorescence (RTP) are highly sought after, however, designing and preparing these materials in an environmentally friendly, scalable, and easy-to-process manner has remained a challenge. Herein, an innovative strategy was achieved by fabricating a series of bacterial cellulose-based RTP nanofiber materials through bio-fermentation, giving remarkable RTP with a long lifetime of up to 858.05 ms. In particular, the cellulose matrix plays a crucial role by providing a rigid environment that stabilizes the excitons in the triplet state and shields them from water and oxygen, thereby boosting the longevity of the RTP. Moreover, the intriguing performance lies in the sensitivity of the RTP of these nanofiber membranes to moisture, enabling them to be repeatedly activated in response to wet/dry stimuli. Inspired by these advantages, these materials are highly suitable for applications such as anti-counterfeiting and information encryption. This research not only presents a groundbreaking strategy for fabricating multi-functional stimuli-responsive materials, but also pushes the boundaries of our understanding of the photophysical properties of cellulose, which may have the potential to inspire future investigations into the development of novel materials with long persistent luminescence and their wide-ranging applications.