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O: Fachverband Oberflächenphysik

O 34: Poster Session III: Organic molecules on inorganic substrates: Adsorption and growth III

O 34.3: Poster

Tuesday, March 2, 2021, 10:30–12:30, P

Investigating kinetics of organic molecules on inorganic substrates — •Anna Werkovits and Oliver T. Hofmann — Institute of Solid State Physics, NAWI Graz, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria

Growth processes of organic thin films are strongly influenced by the interplay of thermodynamics and kinetics. Following Ostwald’s rule of stages, metastable structures often form first during the deposition process. Transitions to more stable structures may be prevented by fast aggregation and growth of the thermodynamically less stable seed, leading to a kinetically trapped polymorph. The selective growth of specific polymorphs, therefore, requires balancing growth and phase transitions via appropriately chosen deposition conditions.

The poster introduces a roadmap for achieving selective growth of organic-inorganic systems and gives an overview of the corresponding challenges and limitations. While thermodynamics can be sufficiently treated by now, kinetics are still an issue as reliable transition state searches devour computational resources. This is primarily caused by the lack of suitable force fields and the high dimensionality of the potential energy surface. We provide first insights about the kinetics for the model system tetracyanoethylene (TCNE) on Cu(111). Energies are obtained using density functional theory (PBE+TS^surf) and transition states mainly with the Nudged Elastic Band method.