Revealing the role of anchoring groups in the electrical conduction through single-molecule junctions.
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.
Zotti
Linda A
LA
Departamento de Física Teórica de la Materia Condensada Universidad Autónoma de Madrid 28049 Madrid, Spain.
Kirchner
Thomas
T
Cuevas
Juan-Carlos
JC
Pauly
Fabian
F
Huhn
Thomas
T
Scheer
Elke
E
Erbe
Artur
A
D004553:Electric Conductivity; D008962:Models, Theoretical