A Novel Ion Species‐ and Ion Concentration‐Dependent Anti‐Counterfeiting Based on Ratiometric Fluorescence Sensing of CDs@MOF‐Nanofibrous Films
Kaitian Zhao, Fan Liu, Hongcan Sun, Pengfei Xia, Junfeng Qu, Changgui Lü, Shenfei Zong, Rong Zhang, Shuhong Xu, Chunlei Wang
Abstract
Abstract Traditional fluorescent anti‐counterfeiting labels based on “on‐off” fluorescence can be easily cloned. It is important to explore advanced anti‐counterfeiting fluorescent labels with high‐level security. Here, a pioneering ion species‐ and ion concentration‐dependent anti‐counterfeiting technique is developed. By successive loading Cu 2+ ‐sensitive yellow emitted carbon dots (Y‐CDs) and Cu 2+ non‐sensitive blue emitted carbon dots (B‐CDs) into metal‐organic frameworks (MOFs) and followed by electrospinning, the B&Y‐CDs@MOF‐nanofibrous films are prepared. The results show that the use of MOF not only avoids the fluorescence quenching of CDs but also improves the fluorescence stability. The fluorescence Cu 2+ ‐sensitivity of the CDs@MOF‐nanofibrous films can be regulated by polymer coating or lamination. The fluorescent label consisting of different Cu 2+ ‐sensitivity films will show Cu 2+ concentration‐dependent decryption information. Only at a specific ion species and concentration (Cu 2+ solution of 40–90 µ m ), the true information can be read out. Less or more concentration (<40 or >90 µ m ) will lead to false information. The identification of the real information depends on both the species and the concentration. After Cu 2+ treatment, the fluorescence of the label can be recovered by ethylenediaminetetraacetic acid disodium (EDTA‐2Na) for further recycling. This work will open up a new door for designing high‐level fluorescent anti‐counterfeiting labels.