Regensburg 2022 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 17: Poster Monday: Organic Molecules at Surfaces 1
O 17.3: Poster
Montag, 5. September 2022, 18:00–20:00, P4
Adsorption structure of mixed PTCDA derivatives on Ag(111) — •Amin Karimi1, Jose M. Guevara1, Veronika Schmalz2, Ulrich Koert2, F. Stefan Tautz1, and Christian Wagner1 — 1Peter Grünberg Institut (PGI 3), Forschungszentrum Jülich , Jülich, Germany — 2Chemistry Department, Philipps Universität Marburg, Marburg, Germany
For molecular manipulation and SPM tip functionalization, the mode of anchoring molecules to the tip is decisive. We recently found that PTCDA binds to a Ag tip with two oxygen-metal bonds after it is retracted from the surface. While this is crucial for its stabilization in a vertical state, the two bonds reduce the degrees of freedom during manipulation in the tip-molecule-surface junction. To overcome this problem, we synthesized a PTCDA derivative (reduced PTCDA), in which one carboxylic oxygen is replaced by two H atoms. For molecular manipulation, this allows choosing between one or two tip-oxygen bonds. Here we present a study on the absorption structures formed by a mixture of PTCDA and reduced PTCDA on the Ag(111) surface with the help of low-temperature NC-AFM/STM. We observe that despite the minimal modification of reduced PTCDA compare to PTCDA, the mixture of both molecules exhibits a strongly different behaviour compared to the regular island growth of pure PTCDA. Particularly striking is the coexistence of zero-, one-, and two-dimensional structures. A likely explanation for such diverse structures is the influence of long-range electrostatic interactions related to the in-plane dipole moment of reduced PTCDA.