Molecular simulation of C 60 adsorption onto a TiO 2 rutile (1 1 0) surface

Abstract

A Monte Carlo molecular simulation study is presented on the adsorption and growth of C 60 films on the surface of the (1 1 0) face of rutile. Simulations are performed for a temperature of 600 K using atomistic models both for the fullerene molecules and the TiO 2 surface. It is found in this work that C 60 is adsorbed preferably in an ordered arrangement along the surface depressions over the exposed undercoordinated Ti cations. At low densities adsorption occurs preferably at alternate rows, with locations in consecutive rows being occupied appreciably only at higher C 60 densities. At low densities, the fullerene molecules tend to aggregate into islands in the surface plane. Additional layers of C 60 form only as the density increases, and do so before a monolayer is completed in all consecutive rows. Full monolayer capacity obtained at the highest densities is about 0.9 C 60 molecules per nm 2, but this is only achieved by completing the packing of molecules in interstices at a slightly upper level. The fraction of the molecules that lie closest to the surface only amounts to 0.6 molecules per nm 2.