<p>Understanding the adsorption mechanisms of organic molecules on graphene and their subsequent influence on the electronic and magnetic properties of this interface is essential in designing graphene based devices. In this thesis we perform first principles calculations based on density functional theory (DFT) in an effort to understand these phenomena. Most organic electronic devices are composed of interfaces formed by the organic overlayer and a metallic electrode. Understanding the charge transfer dynamics at the interface would help engineer efficient organic devices. With this in mind, the first part of research we present is the adsorption of core-excited organic molecules on graphene. We predict the induction or suppression of magnetism in the valence shell of physisorbed and chemisorbed organic molecules on graphene occurring on the femtosecond time scale as a result of core level excitations. We consider three organic molecules: Pyridine - whose interaction with graphene is mainly facilitated by van der Waals forces, Picoline radical - an intermediate case where there is a strong van der Waals interaction of the pyridine π ring with graphene but a covalent bonding of the molecule and pyridine radical - where the interaction is mainly through covalent bonding, and study the ground state and N 1s core excited state electronic properties for these systems. </p>
Abhilash Ravikumar, “Electronic, Spin Dependent Conductive Properties of Modified Graphene”, 2017.