Photopolymerization‐Enabled Spiropyran/MOFs Hybrids: Phase‐Stable Fluorescent Films With Spatiotemporal Resolution and Anti‐Leakage Properties in Multilevel Encryption Systems
Youhao Wei, Haitao Cai, Conghao Wu, Yangyang Gao, Yuanyuan Zi, Jingzhi Wang, Yuhui Yang
Abstract
Abstract Dynamic fluorescent films based on metal‐organic frameworks (MOFs) have emerged as promising candidates for information encryption, yet their practical implementation is hindered by critical challenges in fabrication reliability and performance control. Herein, a novel photopolymerization strategy is presented that synergistically integrates bis‐alkene functionalized spiropyran derivatives with fluorescent MOFs (Tb‐BABDC/Zr‐BABDC) through their intrinsic polymerizable ligand moieties, enabling the fabrication of leakage‐free polyMOF films with enhanced structural integrity. The resulting material simultaneously achieves structural integrity, mechanical flexibility, and time‐dependent fluorescence modulation spanning three emission states (green→yellow→red or blue→purple→red) through UV‐triggered fluorescence resonance energy transfer (FRET). Furthermore, by adjusting the ratio of MOFs and spiropyran, various photochromic behaviors can be achieved. Notably, the covalent immobilization of spiropyran within the photopolymerized matrix addresses three fundamental limitations of conventional physical blending methods: 1) Enhanced stability through covalent bonding prevents spiropyran leakage during operation cycles; 2) Improved phase compatibility eliminates interfacial segregation between organic and inorganic components; 3) Precise performance control allows precise control of spiropyran content and fine‐tunes the photo‐response behavior. The photopolymerized films maintained >95% initial efficiency after 20 switching cycles. This methodology establishes a generalizable platform for developing robust dynamic fluorescent films, significantly advancing MOF‐based materials toward practical encryption applications.