Enhanced Light-Responsive Proton Conduction in MOF-808 via Cooperative Azobenzene and Ionic Liquid Functionalization

Light-responsive proton conductors represent an attractive research direction owing to their potential in intelligent devices and responsive sensing applications. Herein, we present a cooperative functionalization strategy to construct an MOF-based light-regulated proton-conducting material, MOF-808-AZOA-IL, by integrating azobenzene-4,4'-dicarboxylic acid (AZOA) and an ionic liquid (IL) into the MOF-808 framework. AZOA serves as a photoactive unit to endow light responsiveness, while the IL molecules form a continuous proton-conducting network, enhancing the concentration and mobility of protons. This synergy results in a proton-conduction on/off ratio up to ∼2000 of MOF-808-AZOA-IL, with excellent stability over repeated UV light on/off cycles. This work demonstrates that the incorporation of AZOA and IL synergistically enhances the light-regulated proton conduction of MOF-808, offering a reliable strategy for designing advanced stimuli-responsive proton-conductive systems.