Structural, Electronic and Magnetic Properties of Radical-based 2D Covalent Organic Frameworks

Abstract

We designed radical-based two-dimensional (2D) covalent organic framework using tris(2,3,5,6-tetrachlorophenyl)methyl radical building block. We considered four possible AA and AB stacking structures of the radical-based 2D COF and investigated the structural, electronic and magnetic properties. The interlayer distance of the radical-based 2D COF depended on the stacking structure and contact type. The contact between radical building blocks was found to increase the interlayer distance. Also, the thermodynamic stability of the radical-based 2D COF was found to increase as its interlayer distance decreases. The density of states of the radical-based 2D COF showed a finite band gap with intermediate energy levels between the gap. The energy states near Fermi level was mainly occupied by pz orbitals of carbon atoms. The magnetization due to the radical center of the 2D COF was also observed. The magnetic moment of the radical center was in the range of 0.27-0.30, indicating that the unpaired electron of carbon atom was not localized in the radical center.