Self-assembly of Mo6S8 clusters on the Au(111) surface
Physikalische Chemie, TU Dresden, 01062 Dresden, Germany
2 Institute of Physics, TU Chemnitz, 09107 Chemnitz, Germany
3 Institute of Ion Beam Physics and Materials Research, P.O. Box 510119, FZ Dresden-Rossendorf, 01314 Dresden, Germany
Published online: 23 May 2007
The preferred adsorption sites and the propensity for a self-organised growth of the molybdenum sulfide cluster Mo6S8 on the Au(111) surface are investigated by density-functional band-structure calculations with pseudopotentials and a plane wave basis set. The quasi-cubic cluster preferentially adsorbs via a face and remains structurally intact. It experiences a strong, mostly non-ionic attraction to the surface at several quasi-isoenergetic adsorption positions. A scan of the potential energy surface exhibits only small barriers between adjacent strong adsorption sites. Hence, the cluster may move in a potential well with degenerate local energy minima at room temperature. The analysis of the electronic structure reveals a negligible electron transfer and S-Au hybridised states, which indicate that the cluster-surface interaction is dominated by S-Au bonds, with minor contributions from the Mo atom in the surface vicinity. All results indicate that Mo6S8 clusters on the Au(111) surface can undergo a template-mediated self-assembly to an ordered inorganic monolayer, which is still redox active and may be employed as surface-active agent in the integration of noble metal and ionic or biological components within nano-devices. Therefore, a classical potential model was developed on the basis of the DFT data, which allows to study larger cluster assemblies on the Au(111).
PACS: 61.46.-w – Nanoscale materials / 73.22.-f – Electronic structure of nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals / 72.20.-i – Conductivity phenomena in semiconductors and insulators
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2007