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O: Fachverband Oberflächenphysik

O 12: Organic Molecules at Surfaces 2: Characterization of Organic Monolayers

O 12.6: Vortrag

Montag, 5. September 2022, 16:15–16:30, S051

Surface Chemical Bond and Molecular Topology of Polycyclic Aromatic Systems — •Lukas Ruppenthal¹, Florian Münster¹, Benedikt P. Klein¹, Jan Herritsch¹, Leonard Neuhaus¹, Stefan R. Kachel¹, Pengcai Liu², Xing-Yu Chen², Jiawen Cao², Lars E. Sattler³, Sebastian M. Weber³, Qitang Fan¹, Gerhard Hilt³, Xiao-Ye Wang², and J. Michael Gottfried¹ — ¹Department of Chemistry, Philipps-University Marburg, Germany — ²College of Chemistry, Nankai University Tianjin, China — ³Institute of Chemistry, Carl von Ossietzky University Oldenburg, Germany

Metal/organic interfaces have a large impact on the performance of organic (opto-)electronic devices. Therefore, the detailed understanding of their chemical, electronic and geometric structure is important for the further technological development. Many common organic semiconductors contain π-electron systems with alternant topologies, whereas non-alternant alternatives have only recently found increasing attention due to their unusual electronic properties. Here, we compare the alternant polycyclic aromatic molecule pyrene with its non-alternant isomers acepleiadylene and azupyrene regarding their interaction with Cu(111) surface, using PES, NEXAFS, TPD and STM. The non-alternant isomers are also interesting as molecular models of graphene defects, e.g. azupyrene for the Stone-Wales defects. In all cases, the non-alternant isomers show increased metal/molecule-interaction due to their reduced HOMO-LUMO gap, which brings the LUMO energetically closer to the Fermi energy of the metal, causing stronger hybridization with electronic states of the metal surfaces.