2D Piezoelectric Covalent Organic Frameworks: Construction, Characterization, and Potential Applications

2D piezoelectric covalent organic frameworks (2D p ‐COFs) represent a transformative class of materials merging structural precision, symmetry breaking, dynamic covalent chemistry, and electromechanical functionality. Unlike inorganic piezoelectrics (e.g., ZnO, perovskites) or conventional polymers, 2D p ‐COFs leverage their atomically ordered, noncentrosymmetric architectures to achieve efficient mechanical‐to‐electrical energy conversion while offering tunable structure, permanent porosity, and stability. Given the successful examples set by fluoropolymer‐based energy harvesters, grafting fluorine‐substituted alkyl chains onto COFs can facilitate dipole alignment and generate net spontaneous polarization, thereby inducing piezoelectricity. Recent advances in synthesis—fluorinated side‐chain functionalization and hybrid system designs—have enabled large piezoelectric coefficients and high open‐circuit voltages in nanogenerators. This review delves into the core principles of piezoelectricity, construction methodologies, the characterization of distinctive properties, and the burgeoning applications of 2D p ‐COFs in energy harvesting, catalysis, and sensing, while also facing challenges associated with scalability and stability.