Spatiotemporally Controlled Multicolor Luminescence in Supramolecular Co‐Gels for Dynamic Information Encryption

ABSTRACT The escalating demand for advanced information encryption media necessitates materials with complex, dynamic optical properties. While spiropyran‐based supramolecular gels offer a promising photo‐responsive platform, they are constrained by monochromatic fluorescence output and a lack of universal design principles. Hence, we developed novel supramolecular co‐gels via the synergistic co‐assembly of Tb 3 + ions with terpyridine‐functionalized cholesterol and spiropyran ligands. This rational design leverages Tb 3 + ’s long‐lived, narrow green emission as an ideal donor for efficient fluorescence resonance energy transfer (FRET) with the spiropyran's photogenerated merocyanine (MC) form. The co‐gels enable time‐dependent fluorescence modulation across three emission states (green→yellow→orange) via UV‐triggered FRET. Moreover, the molar ratio of cholesterol to spiropyran allows flexible regulation of photochromic behavior, endowing the system with high‐contrast dynamic multicolor luminescence, rapid stimulus response, and excellent fatigue resistance. Noteworthily, the dried gels retain robust responsiveness to multiple external stimuli (light, heat, and mechanical force). This system is distinguished from prior work by three key advantages: multi‐stimulus responsiveness, structural reversibility, and rational designability . This work not only presents a dynamic fluorescent gel for high‐level encryption but also establishes a versatile and rational design strategy for multi‐component supramolecular materials, bridging a critical gap in the field.