Surface functionalization through adsorption of organic molecules

We report a first-principles study about the structural and electronic properties of two hybrid organic-molecule/inorganic-surface interfaces. We consider the adsorption of cysteine amino acids on Au(111) and of styrene molecules on the dimerized Si(100)-(2 x 1) surface, as prototypical systems for the functionalization of both metallic and semiconducting substrates. We focus on the adsorption mechanisms at the submonolayer regime, that we describe in terms of molecule/surface and molecule/molecule interactions. In both cases, our results show a strong electronic mixing and the formation of hybrid bonding states at the interface.