Electronic Structure of Two-Dimensional π-Conjugated Covalent Organic Frameworks

Increasing attention is being given to the development of covalent organic frameworks (COFs) that are based on monolayers of fully π-conjugated structures. At first glance, such two-dimensional (2D) polymer networks could simply be viewed as a mere extension into a second dimension of the quasi-one-dimensional (1D) conjugated polymers at the origin of the field of organic electronics. However, such a view misses essential characteristics coming specifically from 2D lattice symmetry. Our aims in this Perspective are twofold. We seek (i) to provide a conceptual, chemistry-oriented theoretical description of the impact on the electronic structure of this extension from 1D to 2D and (ii) to establish chemical structure-symmetry-electronic property relationships for this class of 2D π-conjugated COFs.