Nonplanar Rhombus and Kagome 2D Covalent Organic Frameworksfrom Distorted Aromatics for Electrical Conduction br

Two-dimensional (2D) covalent organic frame-works (COFs) are an emerging class of promising 2D materialswith high crystallinity and tunable structures. However, the lowelectrical conductivity impedes their applications in electronics andoptoelectronics. Integrating large pi-conjugated building blocks into2D lattices to enhance efficient pi-stacking and chemical doping isan effective way to improve the conductivity of 2D COFs. Herein,two nonplanar 2D COFs with kagome (DHP-COF) and rhombus(c-HBC-COF) lattices have been designed and synthesized fromdistorted aromatics with different pi-conjugated structures (flexibleand rigid structure, respectively). DHP-COF shows a highlydistorted 2D lattice that hampers stacking, consequently limitingits charge carrier transport properties. Conversely,c-HBC-COF,with distorted although concave-convex self-complementary nodes, shows a less distorted 2D lattice that does not interfere withinterlayer pi-stacking. Employing time- and frequency-resolved terahertz spectroscopy, we unveil a high charge-carrier mobility up to44 cm2V-1s-1, among the highest reported for 2D COFs.