SKM 2023 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 22: Poster Session: Organic Molecules on Inorganic Substrates I

O 22.5: Poster

Montag, 27. März 2023, 18:00–20:00, P2/EG

Electronic properties of bi- and peri-tetracene on Cu(111) studied by density functional theory — •Nina Kainbacher¹, Maren Klein^2,3, John B. Bauer³, Holger Bettinger³, Heiko Peisert², and Peter Puschnig¹ — ¹Institute of Physics, NAWI Graz, University of Graz, Austria — ²Institute of Physical and Theoretical Chemistry, University of Tübingen, Germany — ³Institute of Organic Chemistry, University of Tübingen, Germany

Zigzag edged nanographenes with two rows of fused linear acenes, called n-periacenes, have gained increasing attention in the area of organic electronics due to their interesting electronic properties. However, the synthesis is challenging because of their chemical instability. Here we show that a well-ordered monolayer of peritetracene, an n-periacene with four benzene rings in a row, can be produced by depositing the precursor 1,1'-bitetracene on Cu(111) and a subsequent heat treatment. The as-deposited and the annealed films are investigated by STM and UPS and by electronic structure calculations within DFT using a repeated slab approach. We determine the optimal adsorption sites by using damped molecular dynamics and empirical dispersion corrections according to Grimme. We then analyze the electronic structure of the organic/metal interfaces, in particular we focus on the (local) density of states and charge rearrangements upon interface formation which is decisive for the energy level alignment and work function changes. Our results clarify that the interaction of peritetracene with the Cu(111) substrate leads to a charge transfer into the LUMO which is consistent with the experimental observations.