Lanthanide phosphors doped stimuli‐responsive fibres for advanced information encryption and anti‐counterfeiting: In both dark and bright situation

Abstract The increasing prevalence of flexible wearables underscores the urgent need for advanced anti‐counterfeiting technologies. However, photoluminescent anti‐counterfeiting fibre materials are currently plagued by inherent environmental light dependency flaws. Their fluorescence characteristics are more readily discernible under dark‐field or low‐background excitation conditions, and this dependence on specific observation environments consequently limits their capacity to fulfil multi‐modal verification requirements in advanced application scenarios. In response to this pressing challenge, we propose a facile wet‐spinning strategy for fabricating stimuli‐responsive hybrid fibres with reversible optical properties under both ambient light and darkness. Leveraging these dual‐mode optical behaviours, we engineered a dual‐modal encryption system in which encoded information is selectively decrypted under specific lighting conditions. This study sets a promising precedent for the creation of advanced information encryption systems tailored for high‐security applications.