Hydro‐Photo‐Thermo‐Responsive Multicolor Luminescence Switching of a Ternary MOF Hybrid for Advanced Information Anticounterfeiting

Abstract

AbstractDeveloping smart materials capable of solid‐state multicolor photoluminescence (PL) switching in response to multistimuli is highly desirable for advanced anticounterfeiting. Here, a ternary MOF hybrid showing hydro‐photo‐thermo‐responsive multicolor PL switching in the solid state is presented. This hybrid is constructed by co‐immobilizing Eu3+ and methyl viologen (MV) cations within an anionic MOF via the cation‐exchange approach. The confined guest cations are well arranged in the framework channels, facilitating the synergistic realization of stimuli‐responsive multiple PL color‐switching through intermolecular coupling. The hybrid undergoes a rapid and reversible PL color‐switching from red to blue upon water simulation, which is achieved by activating the blue emission of the framework linker while simultaneously quenching the Eu3+ emission. Furthermore, the hybrid displays photo‐thermo‐responsive PL switching from red to dark. UV‐light irradiation or heating triggers the chromic conversion of MV to its colored radical form, which exhibits perfect spectral overlap with Eu3+, thus activating Förster resonance energy transfer (FRET) from Eu3+ to MV radicals and quenching the Eu3+ emission. Inspired by these results, PL morse patterns are designed and fabricated using a novel triple‐level encryption strategy, showcasing the exciting potential of this hybrid in advanced anticounterfeiting applications.