Exquisite Control of Electronic and Spintronic Properties on Highly Porous Covalent Organic Frameworks (COFs): Transition Metal Intercalation in Bilayers

Two-dimensional covalent organic frameworks (2D COFs) are crystalline organic porous materials that are stacked in a layered fashion. In general, these materials have excellent structural tunability, which can be achieved through the various tools of organic synthesis. Their layered and porous nature makes them attractive candidates for electronics, optoelectronics, and catalysis. However, their application is still limited due to relatively poor $\pi$-delocalization. In this paper, we computationally explore a novel 2D COF architecture, consisting of only two crystalline atomic layers comprised of benzene, boroxine, and triazine rings. We study the intercalation of first-row transition metals in the bilayer to enhance and fine-tune their electronic behavior. Furthermore, we perform a systematic study to understand the magnetic behavior of the intercalated transition metals. We found that the concentration and position of transition metals in the structure can drastically change the 2D COFs' electronic and magnetic features. Furthermore, based on their spin-polarized electronic properties, we highlight potential applications in the fields of optoelectronics, photocatalysis, and spintronics.