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O: Fachverband Oberflächenphysik
O 71: Focus Session: Nanoscale Insights into Interfacial Electrochemistry II
O 71.5: Talk
Wednesday, March 14, 2018, 16:45–17:00, HE 101
Electrochemical STM Imaging of J-Aggregates Immobilized on Au(111) — •Iris Dorner1, Matthias Müllner1, Ulrike Diebold1, Jürgen Hauer2, Graig N. Lincoln3, and Stijn F.L. Mertens1 — 1TU Vienna, Institute of Applied Physics, Wiedner Hauptstr. 8-10/134, 1040 Vienna, Austria — 2TU Munich, Associate Professorship of Dynamic Spectroscopy, Department of Chemistry, Lichtenbergstr. 4, 85748 Garching, Germany — 3TU Vienna, Photonics Institute, Gusshausstr. 27, 1040 Vienna, Austria
J-aggregates are supramolecular assemblies of organic dye molecules with characteristic optical and exciton transport properties and have captured interest in photochemistry, photonics and materials science. Although widely characterized in spectroscopic experiments, models for their structure have been waiting for experimental evidence.
We present electrochemical scanning tunnelling microscopy studies with submolecular resolution of the J-aggregate-forming molecule 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidacarbocyanine (TTBC). On bare Au(111), the molecules do not form an ordered structure, which we ascribe to kinetic trapping. If the gold substrate is modified by an iodide adlayer, favourable electrostatic interactions and enhanced lateral diffusion of TTBC yield long-range ordered structures that reflect the hexagonal symmetry of the substrate. Ongoing work aims to reveal to what extent the TTBC adlayer structure is representative of J-aggregates in solution.