Mimicking biological proton pumps to achieve stimuli-responsive protonic solids has long been of great interest for their diverse applications in fuel cells, chemical sensors, and bio-electronic devices. Now, dynamic light-responsive metal-organic framework hybrid membranes can be obtained by in situ encapsulation of photoactive molecules (sulfonated spiropyran, SSP), as the molecular valve, into the cavities of the host ZIF-8. The configuration of SSP can be changed and switched reversibly in response to light, generating different mobile acidic protons and thus high on/off photoswitchable proton conductivity in the hybrid membranes and device. This device exhibits a high proton conductivity, fast response time, and extremely large on/off ratio upon visible-light irradiation. This approach might provide a platform for creating emerging smart protonic solids with potential applications in the remote-controllable chemical sensors or proton-conducting field-effect transistors.
Keywords: MOFs; hybrid membranes; photoswitching; proton conduction; sulfonated spiropyran.
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