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HL: Fachverband Halbleiterphysik

HL 45: HL Posters III

HL 45.35: Poster

Donnerstag, 4. April 2019, 18:30–21:00, Poster E

Taking OLEDs for a Spin — •Nikolai Bunzmann¹, Sebastian Weissenseel¹, Jeannine Grüne¹, Christoph Boehme², Vladimir Dyakonov¹, and Andreas Sperlich¹ — ¹Experimental Physics VI, Julius Maximilian University of Würzburg — ²University of Utah, Salt Lake City, USA

Organic light emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) exhibit a high upconversion rate from non-emissive triplet to emissive singlet states due to a a small energy splitting Δ E_ST between the respective states. Electroluminescence and electrically detected magnetic resonance (ELDMR, EDMR) are suitable methods to investigate such devices as they connect spin-dependent processes with optical and electrical properties. Both techniques were previously used by us to reveal excitation pathways of intermediate excited states in donor:acceptor based TADF OLEDs. However continous wave (cw) experiments do not always allow to fully explain the origin of the observed magnetic resonance effects since different spin- and time-dependent processes may result in indistinguishable spectra. Therefore, we apply pulsed EDMR (pEDMR) to donor:acceptor based TADF OLEDs and by varying the parameters of these experiments such as pulse intensity and length we explore the genesis of TADF emission with respect to interspin coupling and spin relaxation time (T1).