Dual-Guest Encapsulated Metal–Organic Framework with Dual-Stimuli-Responsive Energy Transfer Process for High-Security Information Protection

The development of dynamic luminescent materials that are responsive to multiple stimuli is crucial for information security, but challenges still existing in material design. Herein, we employ an anionic metal–organic framework (MOF), denoted ZJU-64, as a photochemical reaction vessel to assemble two guests, a static energy donor (thioflavin T, ThT) and a photochromic dynamic energy acceptor (merocyanine, MC). The host–guest MC@ZJU-64 and MC&ThT@ZJU-64 materials exhibit reversible powder/fluorescence color switching under alternating exposure to visible light (470 nm) and heat (60 °C). Crucially, the well-defined nanopores not only suppress aggregation but also enable fluorescence resonance energy transfer from ThT to MC. This process can be modulated by light-induced MC isomerization, leading to a wavelength shift of about 200 nm. A proof-of-concept Morse code encryption platform is then demonstrated, where hidden information on different levels can be selectively revealed. This work provides a strategic design for creating smart responsive materials with high-level security functions.