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O: Fachverband Oberflächenphysik

O 58: Poster Session III (Solid/liquid interfaces; Metals; Semiconductors; Oxides and insulators)

O 58.26: Poster

Wednesday, March 28, 2012, 18:15–21:45, Poster B

Characterizing a Charge Transfer Complex by nc-AFM/STM — •Fabian Schulz, Isabel Fernandez-Torrente, Adrian Olivera, Christian Lotze, Martina Corso, Katharina Franke, and Jose Ignacio Pascual — Freie Universität Berlin, Institut für Experimentalphysik, Arnimallee 14, 14195 Berlin, Germany.

The F4-TCNQ/Au(111) metal-organic interface is a promising candidate for the design of molecular organic electronics, due to its potential regarding Fermi level alignment and facilitation of charge-carrier injection. Therefore, much experimental and theoretical effort has been made to understand the charge transfer process taking place upon adsorption of F4-TCNQ on Au(111). Still, the results remain controversial [1], making more in-depth investigations necessary [2].

By combined qPlus noncontact-AFM/STM measurements - in both imaging and spectroscopy mode - we find the co-existence of two different ordered submonolayer F4-TCNQ/Au(111) phases, yielding also two different charge states. One of them shows a Kondo resonance in conductance experiments, indicating the existence of a single occupied molecular orbital and thus, charge transfer of one electron from the substrate to the molecule. Measurements of the local contact potential difference (LCPD) on different molecular sites reveal that the different charge states can be correlated with different LCPD values [3].
Z.G. Soos et al., Organic Electronics 12, 39 (2011).
G.M. Rangger et al., Physical Review B 79, 165306 (2009).
L. Gross et al., Science 324, 1428 (2009).