A deep and detailed understanding of the organic molecule – substrate interaction at the nanoscale is essential in order to develop a real nanoelectronic technology. The combination of Organic molecules and TiO2 surface is becoming a hot topic due to the extended use in novel photovoltaic devices. With this in mind, our group has studied several organic molecules on TiO2(110) surfaces. Thus, fullerenes, C60H30, Pentacene or PTCDI were studied by a combination of experimental and theoretical tools. Now, we expand that works in collaboration with the group of Luca Floreano (ALOISA beamline at Elettra synchrotron) by deeply characterizing Perylene, a prototypical molecule, on TiO2(110)-1×1. By a combination of STM and UPS experiments together with an accurate “many-body” corrected ab initio calculations we showed that the molecular coupling and adsorption configuration strongly depend on the coverage.
- – At low coverage, the surface-molecule interaction is dominated by van der Waals interactions. Perylene adsorb between Obr of the TiO2 surface with their large axis along the  crystallographic direction.
- – At high coverage the molecules self-organize forming large ordered domains. Under these conditions the interaction between molecules is found to be mediated by a strong side-to-side intermolecular hybridization.
The work has been published in J. Phys. Chem. C 2015, 119, 7809-7816