Dresden 2009 – scientific programme

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O: Fachverband Oberflächenphysik

O 40: Methods: Scanning probe techniques I

O 40.4: Talk

Wednesday, March 25, 2009, 15:45–16:00, SCH A316

3D-Force-Spectroscopy and -Dissipation Data of an Organic-Inorganic Interface: PTCDA on Ag(111) — •Daniel-Alexander Braun, Gernot Langewisch, Harald Fuchs, and Andre Schirmeisen — CeNTech (Center for Nanotechnology) & Institute of Physics, University of Münster, Germany

Organic semiconductors have attracted intensive research over the last years. Especially the adsorption of π-conjugated organic molecules on metal substrates in view of potential applications in organic and molecular electronics gained a lot of interest. One of the most studied molecules is 3,4,9,10-perylenetetracarboxylic-dianhydride (PTCDA) and it has been investigated on a wide range of substrates.

Noncontact atomic force microscopy (ncAFM) experiments with PTCDA adsorbed on Cu(111) revealed, that the intramolecular contrast of PTCDA-molecules depends strongly on the local adsorption environment [1]. Here we present experimental ncAFM results of 3-dimensional force and dissipation spectroscopy experiments of PTCDA adsorbed on Ag(111) with submolecular resolution. The dissipation is understood as a hysteresis of forces between approach and retraction of the tip and is caused by bistabilities in the potential energy surface of the tip-sample system. Therefore the dissipation signal can reveal information about the mechanical properties of individual molecules.

[1] B. Such, D. Weiner, A. Schirmeisen and H. Fuchs Applied Physics Letters 89 (2006), 093104