Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 45: Solid / liquid interfaces I
O 45.7: Vortrag
Mittwoch, 28. März 2012, 12:00–12:15, A 060
dI/dV imaging and spectroscopy of single molecules at solid-liquid interfaces — •Jose D. Cojal1, Carlos A. Palma2, Klaus Müllen3, and Jürgen P. Rabe1 — 1Institute of Physics, Humboldt-Universität zu Berlin, Berlin — 2Physik Department E20, Technische Universität München, Garching — 3Max Planck Institute for Polymer Research, Mainz
Scanning tunneling spectroscopy (STS), i.e. superimposing a small high-frequency modulation voltage on the bias and recording the AC current component using a phase sensitive detector (PSD) to obtain the differential of the tunneling current, dI/dV, allows to measure the local density of states (LDOS) at surfaces. This has been widely used at low temperatures and under UHV conditions for metals, semiconductors, organic molecules, carbon nanotubes and graphene. In order to measure both topography and differential tunneling images at solid-liquid interfaces we have modified our home-built STM, and obtained dI/dV maps of single molecules of a monolayer of a hexa-peri-hexabenzocoronene (HBC) derivative, self-assembled at the interface between highly oriented pyrolytic graphite (HOPG) and a molecular solution. This allowed us to better localize HOMO and LUMO of the molecules than previously reported direct measurements of current voltage characteristics [1].
K. Müllen, J. P. Rabe, Acc. Chem. Res. 41 (2008) 511