Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 49: Poster: Nanostructures on Surfaces I
O 49.3: Poster
Dienstag, 13. März 2018, 18:15–20:30, Poster A
Self-assembly & optoelectronic properties of bis- & tetra-pyridil functionalized pyrene molecules — •Domenik Zimmermann1, Knud Seufert1, Luca Dordevic2, Tomas Marangoni2, Davide Bonifazi3, and Willi Auwärter1 — 1Physik-Department E20, Technische Universität München, Germany — 2Department of Chemical and Pharmaceutical Sciences, University of Trieste, Italy — 3Department of Chemical and Pharmaceutical Sciences, University of Trieste, Italy
Pyridil functionalized pyrenes have shown well defined self-assembled structures on Ag(111). Dependent on the number and geometric positioning of the substituents, one-dimensional coordination chains, two-dimensional arrays and chiral, porous kagomé-type networks have been tailored in UHV and were investigated by STM[1].
However, to address the photoactivity of these polycyclic aromatic hydrocarbons an electronic decoupling from the metallic support is mandatory and achieved here by using an insulating layer of h-BN on Cu(111)[2]. On this electronically nanopatterned but topographically weakly corrugated substrate the molecules form self-assemblies reminiscent of the Ag case but show a distinct band gap between prominent HOMO/LUMO states. STS shows a decrease of this gap upon increasing the number of substituents of the pyrene core. This result is confirmed by gas phase DFT calculations and UV-Vis spectra in solution.
[1] Kaposi et al, ACSNano 10, 7665 (2016)
[2] Joshi et al, Nano Letters 12, 5821 (2012)