Dresden 2017 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 70: 2D Materials Beyond Graphene III

O 70.3: Vortrag

Mittwoch, 22. März 2017, 11:00–11:15, WIL A317

Switchable white graphene: electrochemical surface science of the boron nitride nanomesh — •Stijn Mertens — TU Wien, Institut für Angewandte Physik, Wiedner Hauptstraße 8-10/134, 1040 Vienna, Austria — KU Leuven, Chemistry Department, Celestijnenlaan 200F, 3001 Leuven, Belgium

On Rh(111), a monolayer of hexagonal boron nitride (h-BN) forms a so-called nanomesh superstructure [1] with a 3.2-nm lattice constant and strong electronic corrugation, useful for trapping atoms and molecules [2,3].

We show by electrolyte-to-vacuum transfer experiments and thermal desorption spectroscopy that hydrogen underpotential deposition (H upd) [4] leads to submonolayer quantities of hydrogen intercalated between the h-BN overlayer and Rh(111). In situ STM reveals that this lifts the corrugation of the nanomesh and is fully reversible under potential control. Copper upd is used to quantify the defect density in the nanomesh, and to determine the electrochemical window where the nanomesh is stable. Dynamic contact angles of an electrolyte drop show that the microscopic change within the 2-dimensional material leads to a macroscopic effect related to a 10% change in adsorption energy [4]. The static friction on the other hand, which can be extracted by extending the Young equation for non-equilibrium effects, remains unchanged for the surface in the two states.

[1] Corso et al., Science 303 (2004) 217. [2] Berner et al. Angew. Chem., Int. Ed. 46 (2007) 5115. [3] Dil et al. Science 319 (2008) 1824. [4] Mertens, Greber et al. Nature 534 (2016) 676.

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