Regensburg 2022 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 41: Organic Semiconductors 2

HL 41.5: Vortrag

Freitag, 9. September 2022, 10:30–10:45, H34

Exploring the interplay of oriented molecules and device performance by post-annealing studies of organic light-emitting diodes — •Dinara Samigullina, Christian Hänisch, Karl Sebastian Schellhammer, and Sebastian Reineke — Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute of Applied Physics, Technische Universität Dresden, Germany

Organic light-emitting diodes (OLEDs) have been widely investigated in the last decades exploring strategies to enhance their performance. Nevertheless, a thorough understanding of the microscopic processes during the thin-film formation and morphology evolution is quite challenging and under debate in many facets. In this work, we present a comprehensive study of the influence of post-annealing on the optoelectronic performance of OLEDs. In addition to standard characterisation techniques such as spectroscopy and electrical measurements, we use impedance spectroscopy in order to probe the change in polarisation of organic thin films depending on the annealing temperature. We show, how the orientation of permanent dipole moments (PDMs) in thin films can be manipulated by post-annealing and connect this to improved electrical performance. Moreover, angle-resolved emission spectra reveal the influence of heating on the orientation of the transition dipole moment (TDM) of emitting molecules. In such manner, the correlation between annealing temperature and orientation of PDMs and TDMs is studied while taking into consideration the optoelectronic properties of OLEDs.