Berlin 2018 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 71: Organic Electronics and Photovoltaics - OLEDs and Molecular Excitations

CPP 71.1: Vortrag

Donnerstag, 15. März 2018, 15:00–15:15, C 243

Intra- and Intermolecular TADF emission investigated by magnetic resonance methods — •Nikolai Bunzmann¹, Benjamin Krugmann¹, Sebastian Weissenseel¹, Gintare Grybauskaite-Kaminskiene², Dmytro Volyniuk², Andreas Sperlich¹, Juozas V. Grazulevicius², and Vladimir Dyakonov^1,3 — ¹Experimental Physics VI, Julius Maximilian University of Würzburg — ²Kaunas University of Technology, Lithuania — ³Bavarian Center for Applied Energy Research (ZAE Bayern)

Organic light emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) utilize molecules with a small energy splitting Δ E_ST between singlet and triplet states. This can either be realized in intramolecular charge transfer states of molecules with near-orthogonal donor and acceptor moities or in exiplex states formed between a proper combination of individual donor and acceptor materials. Here, we investigate 4,4’-(9H,9’H-[3,3’-bicarbazole]-9,9’-diyl)bis(3-(trifluoromethyl) benzonitrile) (pCNBCzmCF3), which shows intramolecular TADF but simultaneously can form intermolecular exciplex states in combination with 4,4’,4”-Tris[phenyl(m-tolyl)amino]triphenylamine (m-MTDATA). In order to reveal which triplet states are involved in the RISC mechanism for both types of TADF emission, we apply electroluminescence and photoluminescence detected magnetic resonance (ELDMR, PLDMR). Thereby, we draw a comprehensive picture of which intermediate states are populated between optical or electrical excitation and light emission.