SKM 2023 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 17: Poster Session I

CPP 17.12: Poster

Montag, 27. März 2023, 18:00–20:00, P3

On the orientation mechanism of non-polar dyes in light-emitting guest-host systems — •Binh-Minh Nguyen, Markus Schmid, Johann Kirsch, and Wolfgang Brütting — Experimental Physics IV, Institute of Physics, University of Augsburg, 86159 Augsburg, Germany

After many years of development, OLEDs have continuously been optimized to reach higher efficiency, for which the horizontal orientation of the emitter molecules is one of the dominant factors [1]. For the purpose of studying intrinsic orientation without electrostatic interaction, our work considers non-polar dyes, namely TTPA, BSBCz, DIP and DBP. While the emitter orientation has been studied in neat film as a basic approach, their behavior in guest-host systems has not been studied widely. In this work we focus on the correlation between emitter concentration and its orientation. With the results from experimental and simulation study, we also discuss the possible orientation mechanism of emitter molecules on the substrate surface in terms of molecular structure, possibility to form crystallites and the effective glass transition temperature of the guest-host system. We observe that isotropic structure of the emitter as well as the crystallized and aggregated molecules are not favorable for horizontal orientation. However, molecules having a rod-like structure have the tendency to arrange horizontally to the substrate. These results contribute to a further understanding of orientation of non-polar emitter molecules.

[1] Brütting et. al, Physical Review Applied, 2017, 8(3), 037001.