Berlin 2024 – scientific programme

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DS: Fachverband Dünne Schichten

DS 17: Organic Thin Films, Organic-Inorganic Interfaces

DS 17.3: Talk

Thursday, March 21, 2024, 15:30–15:45, A 060

Ab-initio study on mixed donor-acceptor adlayers: Structure, stoichiometry and electrostatic potential of F4TCNQ and 1H,1 H-[4,4]bipyridinylidene on Cu (111) — •Richard Berger and Oliver Hofmann — Petersgasse 16, 8010 Graz, TU Graz: Institut für Festkörperphysik

Adlayer patterns formed from heterogenous molecular species on a substrate surface are of great interest, especially in the case of 2-dimensional donor-acceptor patterns adsorbed on metal surfaces. Such adsorbed donor-acceptor patterns exhibit various remarkable characteristics, such as their ability to form two-dimensional charge density waves or the possibility of tuning the electron injection barrier at the interface via the stoichiometry of the mixed adlayer. Here, we computationally investigated the exemplary donor-acceptor system of F4TCNQ and 1H,1 H-[4,4]bipyridinylidene on the Cu (111) surface. We predict the thermodynamically stable adlayer structure for different mixing stoichiometries. This allows us to forecast the tunability of the on-surface stoichiometry and structure via the gas phase concentration ratio during the deposition process. Using these predictions, we explore how the complex electrostatic potential of the donor/acceptor mixture affects the barriers for charge injection into subsequent layers.

Keywords: Donor-Acceptor adlayers; Structure search; charge injection