Room-Temperature Interfacial Synthesis of Vinylene-Bridged Two-Dimensional Covalent Organic Framework Thin Film for Nonvolatile Memory

The development of large-area two-dimensional all sp2 carbon-linked covalent organic frameworks (COFs) film still remains a challenge, because of the shortage of the effective synthesis methods and optimal building blocks. To date, all vinylene-bridged COFs synthesized by solvothermal method at high temperatures and pressures are insoluble and unprocessable powders, which lead to a formidable challenge in fabricating thin film-based electronic and optoelectronic devices. By using a liquid–liquid interface polymerization strategy, a vinylene-bridged COF film with a complete sp2-carbon skeleton has been successfully synthesized for the first time at room temperature. The COF nanospheres initially formed at the liquid–liquid interface slowly transmuted themselves into self-standing COF thin films with long-range ordered arrangement by covalent self-assembly. The as-fabricated electronic device with a configuration of Al/COFs/ITO exhibited a nonvolatile rewritable memory effect with a low switching-on voltage of +0.84 V. Associated with its bistable switching performance, this device is capable of executing simple "OR" logic operations.