Multi‐Stimuli‐Responsive Lanthanide‐Functionalized HOFs for Multi‐Level Information Encryption and Biomarker Ratiometric Probe

Enhancing the concealment of information encryption labels necessitates the development of multi‐level optical encryption technologies utilizing dynamic luminescence. Herein, an innovative strategy is reported for constructing multi‐stimuli‐responsive luminescent materials by incorporating the stimuli‐responsive photonic units (SRPUs), Tb 3 ⁺ and 2,6‐pyridine dicarboxylic acid (DPA), into a blue‐emissive hydrogen‐bonded organic framework (HOF‐20). The first‐obtained Tb 3 ⁺@HOF‐20 composite serves as a sensitive fluorescence probe for DPA, exhibiting a dynamic blue‐to‐green emission color shift upon DPA coordination, with a low limitation of detection of ≈37 n m . Altering the excitation wavelength from 280 to 340 nm would induce the green‐to‐blue color change. Furthermore, leveraging the pH‐responsiveness of DPA, the DPA@Tb 3 ⁺@HOF‐20 system can also demonstrate the reversible green‐to‐blue fluorescence switching under pH modulation. Capitalizing on these multiple stimuli (DPA concentration, excitation wavelength, pH value), the multi‐level information encryption is successfully demonstrated by using a Tb 3 ⁺@HOF‐20‐based agarose hydrogel membrane. This approach of integrating diverse SRPUs within HOFs not only provides a novel pathway for designing intelligent optical materials with abundant responsiveness but also significantly advances the application frontiers of information encryption labels.