Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 25: Organic Molecules on Inorganic Substrates III: Adsorption & Growth
O 25.2: Vortrag
Dienstag, 19. März 2024, 10:45–11:00, MA 043
CoPc/F16CuPc on Ag(100): Triggering the condensation of a 2D molecular gas — •Thorsten Wagner1, Blazej Golyszny2, Grazyna Antczak2, and Peter Zeppenfeld1 — 1Institute of Experimental Physics, Johannes Kepler University Linz, Austria — 2Institute of Experimental Physics, University of Wroclaw, Poland
When metal phthalocyanine molecules are deposited on metallic surfaces, they often form a 2D molecular gas in the submonolayer regime: Instead of a fixed position as in a condensed phase such as 2D islands, they are very mobile on the surface and change frequently their adsorption sites and geometry. The reason for this is a so-called surface-mediated repulsion, which may stabilizes the 2D gas phase even far beyond a coverage of 0.5 ML. This repulsion can be compensated by using mixtures of hydrogen- and fluorine-termined phthalocyanines. Here, we use photoelectron emission microsopy (PEEM) to investigate ultrathin films of cobalt-Pc (CoPc) and perfluorinated copper-Pc (F16CuPc) on Ag(100) surfaces. By following the evolution of the standard deviation1 of the image sequences acquired during subsequent deposition of the molecules, the 2D molecular gas and the condensed bi-molecular phase can be identified. Regardless of the sequence of deposition, first CoPc and then F16CuPc or vice versa, we can trigger the condensation of the 2D gas into a dense structure with a 1:1 ratio of the two molecules. The mixing of the molecules is actually not limited to the first layer on the substrate.
[1] Th. Wagner et al. in Ultramicroscopy 233, 113427 (2022)