SurfaceScience21 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 93: Poster Session VII: Graphene and beyond I

O 93.4: Poster

Donnerstag, 4. März 2021, 10:30–12:30, P

Modeling the self-assembly of graphene flakes on liquid Cu — •Juan Santiago Cingolani, Mie Andersen, and Karsten Reuter — Chair of Theoretical Chemistry, Technical University of Munich, Germany

The use of liquid Cu as a catalyst for the production of graphene during chemical vapor deposition has been shown to lead to high-quality single layer millimeter-scale graphene flakes. In-situ optical microscopy revealed that the flakes are mobile on the liquid surface and interact with each other leading to the formation of self-assembled structures. We carry out a series of molecular dynamics simulations of graphene flakes on liquid Cu employing the third-generation charge optimized many body potential (COMB3) to shed some light on the origin of such inter-flake interactions.

From our simulations we extract information regarding the interaction of the flakes with the liquid substrate; namely the adsorption height, interaction energy, and charge transfer into the adsorbate. We extrapolate these properties to the limit of large flakes and use them as input for a mesoscopic model which accounts for electrostatic repulsion and capillary attraction assuming charged spherical particles. The resulting interaction potential predicts interflake distances within an assembly that lie within an order of magnitude of the experimental observations. While quantitative agreement is out of the scope for such a simple model, we show that the experimental observations are compatible, under the proposed mesoscopic model, with the microscopic properties derived from atomistic simulations.