Dresden 2011 – scientific programme

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MO: Fachverband Molekülphysik

MO 18: Experimental Techniques and Various Topics

MO 18.7: Talk

Wednesday, March 16, 2011, 18:00–18:15, MER 02

Metal-molecule contacts in liquid environments — •Sascha Berger¹, Jannic Wolf², Thomas Kirchner², Thomas Huhn², Elke Scheer², and Arthur Erbe¹ — ¹Helmholtz-Zentrum Dresden-Rossendorf — ²Universitaet Konstanz

The definition of metal-molecule contacts is the first step on the development of molecular electronic components. Using the mechanically controlled break junction (MCBJ) technique single molecules can be contacted reliably under varying conditions. Here we demonstrate contacts to oligo (phenylene-ethynylene) molecules with two or three phenylene units, which are attached to the metal electrodes via Thiol anchoring groups, in a liquid environment. The junctions are characterized by recording current-voltage (I-V) characteristics. From these curves we extract the position of the molecular energy level, which contributes to the electric current through the junction, and the strength of the coupling to the electrodes. We can show that symmetric coupling to the two metallic electrodes leads to symmetric I-V-curves, while asymmetric coupling is reflected in asymmetric curves. We demonstrate that controlled changes in the design of the molecules lead to changes in the conduction properties of the junctions.