In this study, recently published in Chemistry, A European Journal, we present a full picture of the adsorption of a C60 monolayer on the TiO2(110) surface: a typical acceptor organic molecules on a wide gap dielectric surface. The combination of experimental techniques and density functional calculations including the Van der Waals interaction has allowed us to understand this model system.
We show that the adsorbed molecular layer floats on the surface confined between the prominent bridging O rows at a distance of about 3.2 Å with respect to the Ti 5-fold coordinated plane. This layer is electronically decoupled from the substrate, even at submonolayer coverage. Fullerenes, as a consequence of their high diffusion coefficient at room temperature and their confinement between different O rows, present correlated rotations due to the conservation of the total angular momentum of two neighboring molecules. This rotation leads to molecular spinning along the surface normal direction.
STM image of C60 on TiO2 and the model derived from the image
Read our complete scientific article here Chem.-Eur. J. 18, 7382 (2012)