Regensburg 2010 – scientific programme

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O: Fachverband Oberflächenphysik

O 29: [CPP] Organic Electronics and Photovoltaics I (Joint Session DS/CPP/HL/O)

O 29.3: Talk

Tuesday, March 23, 2010, 10:00–10:15, H37

Radical Molecular Wires — •Georg Heimel¹, Egbert Zojer², Lorenz Romaner³, Jean-Luc Brédas⁴, and Francesco Stellacci⁵ — ¹Institut für Physik, Humboldt-Universität zu Berlin, Germany — ²Institut of Solid State Physics, Graz University of Technology, Austria — ³Chair of Atomistic Modeling and Design of Materials, University of Leoben, Austria — ⁴School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, USA — ⁵Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, USA

The technological relevance and the functionality of semiconducting materials originate in the fact that their conductivity and the band alignment at the interfaces with other materials can be controlled through doping. Here, we consider the ultimate miniaturization of functional devices by computationally investigating the doping of molecular wires suspended between two metal electrodes.¹ For representative systems we find that, upon doping, the molecular conductivity is enhanced by more than two orders of magnitude. We elucidate the microscopic origin of this dramatic effect and present an intuitive picture, which rationalizes our observations in terms of Fermi-level pinning. Our results shed new light on recent experimental findings and, most importantly, in-depth understanding of the doping mechanism enables the targeted development of new functional components for sensing and switching at the single-molecule scale.
[1] G. Heimel et al., Nano Lett. 9, 2559 (2009).