Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 98: Plasmonics and Nanooptics V
O 98.2: Vortrag
Freitag, 4. April 2014, 10:45–11:00, TRE Ma
Electroluminescence of single oligothiophene wire suspended in a STM junction. — •Gaël Reecht1, Fabrice Scheurer1, Virginie Speiser1, Fabrice Mathevet2, Yannick Dappe3, and Guillaume Schull1 — 1IPCMS , Strasbourg, France — 2Laboratoire de Chimie des Polymères, Paris, France — 3IRAMIS CEA, Saclay, France
In a pioneering experiment [1], it has been demonstrated that the fluorescence of a single molecule could be excited using a scanning tunnelling microscope (STM). In this case the molecule was separated from the electrodes by thin insulating layers. For direct molecule-electrode contacts experiments [2], luminescence mechanisms intrinsic to the molecule are quenched because of the strong hybridization with the electrode states. Combining direct molecule-electrode coupling and fluorescence in a same junction is therefore a challenging key issue towards molecular optoelectronic devices.
Here we used the tip of a low temperature STM to lift a unique π-conjugated polymer chain from a Au(111) surface. For positive sample voltage, passing current through the suspended molecular wire induced an emission of light whose spectral and voltage dependencies are consistent with the fluorescence of the wire junction mediated by localized plasmons. For the opposite polarity the emission is strongly attenuated. Our molecular contact junction can therefore be viewed as a single molecular wire light emitting diode.
[1]. X. H. Qiu, and al. Science 299, 542 (2003).
[2]. N. L. Schneider, and al. Phys. Rev. Lett.109, 186601 (2012).