Field of Expertise: Advanced Material Science

Charge transport through molecular monolayers: Influence of collective effects and docking groups
Veronika Obersteiner, David A. Egger, Georg Heimel, Egbert Zojer
Institute of Solid State Physics
15:20 - 17:30 Thursday 24 October 2013 Foyer Alte Technik

In the context of transport through molecular-based systems, it has been increasingly acknowledged over the past years that there are fundamental differences between individual molecules and continuously-extended, two-dimensional monolayers [1] [2]. Here, we aim at relating those differences to effects that originate from the collective electrostatic interactions between the molecules in an extended system [3]. This is demonstrated by varying the coverage in self-assembled monolayers (SAMs) consisting of organic molecules with dipoles distributed along their backbones. These coverage-dependent calculations are done using density functional theory (DFT) applying a slab-type approach. To determine the transport properties, the transmission coefficients are calculated applying a Greens function approach. Since the docking chemistry strongly affects electrical transport [4], we also investigate the influence of different anchoring groups forming the contact between the SAMs and the gold electrodes.

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[4] L. A. Zotti, T. Kirchner, J.-C. Cuevas, F. Pauly, T. Huhn, E. Scheer and A. Erbe, Small 2010, 6, 1529 .