Covalent Organic Frameworks: Structures, Synthesis, and Applications

TLDR

Covalent organic frameworks are crystalline porous polymers assembled from predesigned molecular building units linked by covalent bonds, providing precise 2‑ and 3‑dimensional positional control that yields rigid, highly regular structures with tunable chemical and physical properties. This feature article surveys the diverse COF structures that have been realized to date in the rapidly expanding field of covalent organic framework development. The review examines synthesis strategies tailored for high crystallinity, ease of processing, and thin‑film formation, and discusses emerging applications in gas storage, separations, sensing, electrochemical energy storage, and optoelectronics.

Abstract

Abstract Covalent organic frameworks (COFs) are crystalline porous polymers formed by a bottom‐up approach from molecular building units having a predesigned geometry that are connected through covalent bonds. They offer positional control over their building blocks in two and three dimensions. This control enables the synthesis of rigid porous structures with a high regularity and the ability to fine‐tune the chemical and physical properties of the network. This Feature Article provides a comprehensive overview over the structures realized to date in the fast growing field of covalent organic framework development. Different synthesis strategies to meet diverse demands, such as high crystallinity, straightforward processability, or the formation of thin films are discussed. Furthermore, insights into the growing fields of COF applications, including gas storage and separations, sensing, electrochemical energy storage, and optoelectronics are provided.