Tuning the Adsorption of Aromatic Molecules on Platinum via Halogenation

The interaction of aromatic molecules with metal surfaces is of key relevance for the functionality of molecular electronics and organic electronics devices. One way to control and tune the binding properties of molecules to metals is chemical functionalization. The adsorption of halogenated benzene molecules on the (111) surface of platinum is here investigated by density functional theory calculations with nonlocal van der Waals correlation functional. It is found that these systems exhibit a bistable adsorption energy profile with (meta)stable chemisorption and physisorption states separated by a potential energy barrier. The relative stability of these states can be tuned by functionalizing benzene with a different number or type of halogen atoms. Our results suggest a simple rational molecular design to achieve the desired interfacial binding in organic electronic devices and in composites with interfaces between large aromatic molecules and metals.