SAMOP 2023 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 6: Poster I

MO 6.16: Poster

Dienstag, 7. März 2023, 16:30–19:00, Empore Lichthof

Coverage-dependent agglomeration in molecular films on atomically flat surfaces — •Erik von der Oelsnitz, Tim Völzer, Julian Schröer, Rico Schwartz, Tobias Korn, and Stefan Lochbrunner — Institute of Physics, Albert-Einstein-Straße 23-25, 18059 Rostock, Germany

The deposition of a thin, monomeric molecular layer on an atomically flat surface, as it is provided by Van-der-Waals crystals, is crucial to the functionalization of such layered materials and the fabrication of corresponding hybrid structures. In this work, Perylene Orange (PO) molecules were coated onto a thin exfoliated hexagonal boron nitride layer using thermal vapor deposition (TVD) at various evaporation temperatures. The resulting hybrid structures were examined by a fluorescence lifetime imaging microscope, revealing a biexponential fluorescence decay, as well as by micro-photoluminescence spectroscopy, proving for low evaporation temperatures the monomeric nature of the PO layer. Upon increasing the temperature, the fluorescence intensity rises and at the same time the fast decay component becomes dominant and a low-energy band emerges in the emission spectrum. Interestingly, the slow decay time remains pretty constant. Therefore, this slow component can be assigned to the fluorescence decay of PO monomers, whereas the fast decay component can be attributed to agglomerates that form at higher coverage and provide additional decay channels such as the relaxation into excimer states. From these findings, an optimum for the vaporization temperature can be determined, which will be used in future applications.