Controllable Interfacial Growth of 2D Covalent Organic Framework Films for Organic Electronic Applications

Two-dimensional covalent organic frameworks (2D COFs) are crystalline porous materials with predesignable topologies, periodic structures, and tunable functionalities constructed from molecular building blocks through covalent bonds. Their modular design allows for the integration of various functionalities, making 2D COFs highly suitable for optoelectronic applications. 2D COF films have emerged to integrate 2D COFs into optoelectronic devices, avoiding the low dispersibility and poor processability of powder COF materials. Interfacial polymerization is a blooming method to fabricate 2D COF films at the liquid-solid, liquid-liquid, water-air, and solid-gas interfaces. Obtaining high-quality 2D COF films is key to exploring their performance in organic electronics. This review first discussed the synthetic strategies for constructing highly crystalline and oriented 2D COF films by interfacial polymerization, including general nucleation-growth process, field-induced assembly and nucleation-growth, and other methods. The applications of 2D COF films in organic electronic devices are reviewed, including photodetectors, organic transistors, electrochromic devices, resistive memory, and neuromorphic devices. Finally, the challenges and perspectives in synthesizing of 2D COF films and their applications are outlined.