Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

Revealing the role of anchoring groups in the electrical conduction through single-molecule junctions

Zotti, L. A.; Kirchner, T.; Cuevas, J.-C.; Pauly, F.; Huhn, T.; Scheer, E.; Erbe, A.

A combined experimental and theoretical study is presented revealing the influence of metal-molecule coupling on electronic transport through single-molecule junctions. Transport experiments through tolane molecules attached to gold electrodes via thiol, nitro, and cyano anchoring groups are performed. By fitting the experimental current-voltage characteristics to a single-level tunneling model, we extract both the position of the molecular orbital closest to the Fermi energy and the strength of the metal-molecule coupling. The values found for these parameters are rationalized with the help of density-functional-theory-based transport calculations. In particular, these calculations show that the anchoring groups determine the junction conductance by controlling not only the strength of the coupling to the metal but also the position of the relevant molecular energy levels.

Keywords: anchoring groups; break junctions; density functional theory; molecular electronics; molecular wires

Publ.-Id: 14372