Fabrication of ultra-thin 2D covalent organic framework nanosheets and their application in functional electronic devices

Ultra-thin two-dimensional (2D) covalent organic frameworks (COFs) nanosheets have received widespread interests in functional electronic devices due to their advantages of high porosities, large specific surface areas, tunable structures, abundant active sites, good crystallinity and rich π-electron array. In this review, we first presented the introduction of ultra-thin 2D COF nanosheets. Subsequently, we discussed the typical synthetic strategies of COF nanosheets including top-down strategies and bottom-up strategies. Then, we summarized the application of ultra-thin 2D COF nanosheets in functional electronic devices including field effect transistor, photodetector, battery, supercapacitor, fluorescence sensor and electrochemical sensor. Finally, we discussed the challenges and prospects for the synthesis and multifunctional application of ultra-thin 2D COF nanosheets.