SKM 2023 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 12: Poster

DS 12.8: Poster

Mittwoch, 29. März 2023, 17:00–19:00, P3

Synthesis of structurally defined graphene nanoribbons: Peri-tetracene and its corresponding 1,1-bitetracene precursor — •Maren Klein^1,2, John B. Bauer², Marie Wagner^1,2, Holger F. Bettinger², Thomas Chassé¹, and Heiko Peisert¹ — ¹Institute of Physical and Theoretical Chemistry, University of Tübingen, Germany — ²Institute of Organic Chemistry, University of Tübingen, Germany

Band gap engineering of precise nanographenes has attracted much attention in the field of organic electronics as they show great electronic properties. One class of these promising nanographenes are acenes and their related peri-acenes. Acenes are linearly condensed polycyclic hydrocarbons whereas peri-acenes exhibit a two-dimensionally enlarged π system. As peri-acenes possess a diradical open-shell character, the synthesis is quite challenging. Here we demonstrate that peri-tetracene can be formed on-surface by annealing the deposited precursor molecule 1,1-bitetracene on a Cu (111) surface. The unique 1,1-bitetracene undergoes a surface-assisted cyclodehydrogenation which was investigated by microscopic and spectroscopic techniques, as well as by DFT calculations. In the XAS spectra we could observe that the as-deposited molecule shows a vanishing intensity of π* transitions at normal incidence (90^∘), which indicates a planarization of the molecule already before annealing and an almost flat lying adsorption geometry.