Berlin 2018 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 42: Poster: Organic-Inorganic Hybrid Systems and Organic Films

O 42.9: Poster

Dienstag, 13. März 2018, 18:15–20:30, Poster A

Molecular dynamics simulation of transport and nucleation of conjugated organic molecules on inorganic surfaces — Mila Miletic, Joachim Dzubiella, and •Karol Palczynski — Institut für Weiche Materie und Funktionale Materialien, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner Platz 1, 14109 Berlin, Germany

In our study we analyze the influence of polarity on the surface transport and nucleation of conjugated organic molecules on the inorganic amorphous SiO₂ and ZnO surfaces by means of all-atom molecular dynamics simulations. In particular, we thoroughly investigate the effects of partial fluorination of the popular para-sexiphenyl (p-6P) molecule with chemical modifications of one head group (p-6PF2) or both head and tail (p-6PF4). Even though the chemical modifications do not lead to significant changes in the molecular structure, the effect of the fluorination on the diffusion process on the ZnO substrate is considerable, leading to a difference in the diffusion barriers of one order of magnitude between p-6P and p-6PF4. However, in case of the amorphous SiO₂ substrate, the difference in the diffusion barriers between p-6P and p-6PF2 is negligible. To fully understand the effects that controll the diffusion mechanisms, our aim is to investigate the relation between the surface barriers and the underlying surface dynamics, as well as to characterize substantial contributions of entropy to the effective diffusion barriers. Furthermore, we employ molecular dynamics simulations to identify the sources of nanometer-scale disorder in organic crystal structures on inorganic substrates.