SKM 2023 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 7: Poster I

HL 7.24: Poster

Monday, March 27, 2023, 13:00–15:00, P2/EG

Highly dipolar molecule on single crystals: Impact of chemical affinity on the interface formation — •Baris Öcal and Selina Olthof — Department of Chemistry, University of Cologne, Greinstraße 4-6, 50939 Cologne, Germany

Merocyanines are functional dyes with interesting electronic properties due to their resonant structure between charged and uncharged states. Their bandgap can be widely tuned via the donor and acceptor strength, which makes them interesting as active material in organic-based solar cells, especially since they show very strong absorption. Their physical properties can be further improved by ordering them. The ordering of the molecules is closely related to initial growth on the substrate underneath and interaction between this substrate and molecule. In my work, I investigate the effect of substrate/molecule and molecule/molecule interactions on the electronic structure by photoelectron spectroscopy methods. Highly dipolar HB238 merocyanine has been chosen to observe the chemical interaction and its effect of the charge states of the molecule easier. Surfaces such as SiC/graphene, Au(100), Ag(100) and Cu(100) are used as templating substrates due to their different chemical affinity and ordered structure. Thickness dependent X-ray Photoelectron spectroscopy (XPS) measurements helps us to understand the chemical effect of substrate on the charge states, while Ultraviolet Photoelectron Spectroscopy (UPS) measurement gives information on the molecular phase changes such as dimerization, orientation change. We find that chemical interaction of the substrate significantly affects molecule/molecule interaction.