SKM 2023 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 28: Organic Molecules on Inorganic Substrates III: Adsorption and Growth I

O 28.1: Vortrag

Dienstag, 28. März 2023, 10:30–10:45, CHE 89

Tuning interfaces properties via deposition conditions: thermodynamic's deed and kinetic's contribution — Anna Werkovits, Johannes J. Cartus, Lukas Hörmann, and •Oliver T. Hofmann — Institute of Solid State Physics, Tu Graz

The interface dipole of an inorganic-organic interface depends strongly on the structure, i.e. the polymorph, the organic molecules assume. This is not a subtle effect: In the past years, studies reported work functions differing between up to 3 eV between different polymorphs, illustrating how important it is to control the growth of these interfaces.

In this work, we discuss on the basis of first-principle calcuations how the molecule-substrate, the intermolecular interaction and the size of the molecule affect the relative thermodynamic stability of different phases for different deposition conditions, and how this directly relates to observed work function changes. Based on this, we discuss two ways strategies to tune interface properties. Either, the relative stability can be modified, e.g. by growing the interface in an electric field. Alternatively, it is also possible to exploit kinetic effects during the growth and trap desired phases. Based on the example of TCNE on Cu(111) we discuss how a given phase can be kinetically trapped, and under which circumstances we expect thermodynamic equilibrium to prevail.