Facile Synthesis of Conductive Metal-Organic Frameworks Nanotubes for Ultrahigh-Performance Flexible NO Sensors

Cu-benzenehexathiol (Cu-BHT) has attracted significant attention due to its record high electrical conductivity and crystal defects Cu_2c . However, the nonporous structure and small specific surface area of Cu-BHT with two-dimensional kagome lattice invariably limit its practical application in sensing and catalysis. In this work, Cu-BHT nanotubes (Cu-BHT-NTs) are designed and prepared via a facile homogeneous reaction to solve these problems. Compared with the traditional nanorod-like structure, the Cu-BHT-NTs not only have a higher specific surface area but also possess a higher proportion of crystal defects (66.6%). The successfully configured DPPTT/Cu-BHT-NTs heterostructure organic field-effect transistor (OFET)-based sensor exhibits excellent sensitivity as high as 13 610%, a minimum detection limits down to 5 ppb, and exceptional selectivity to nitric oxide (NO) toxic gases. Theoretical analysis systematically shows that Cu_2c sites in the Cu-BHT-NTs increase the number of electrons transferred from the heterostructure to NO molecules, confirming that the high sensitivity and selectivity result from the high binding between Cu-BHT-NTs and NO molecules. Furthermore, a fully flexible device based on the heterojunction OFET sensor is prepared to ensure the convenience of wearing and carrying gas sensors, opening up a new avenue for the next generation of wearable intelligent electronics.