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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 17: Poster I

CPP 17.16: Poster

Montag, 9. März 2026, 19:00–21:00, P5

Spin-Sensitive Spectroscopy of TADF OLEDs — •Andreas Kohrmann, Ahmed Mohamed, Vladimir Dyakonov, and Andreas Sperlich — Experimental Physics 6, University of Würzburg, 97074 Würzburg, Germany

The performance of the blue emitter ν-DABNA in thermally activated delayed fluorescence (TADF) organic light-emitting diodes (OLEDs) is closely related to the dynamics of triplet excitons. In optically excited host-guest thin films, triplet states are generated and evolve through the intricate interplay of triplet diffusion, triplet recombination, and triplet-triplet annihilation (TTA). Thereby TTA and triplet diffusion are inherently host-dependent. Consequently, the host environment exerts a pivotal influence on exciton loss and delayed emission pathways. We used spin-sensitive optical spectroscopy, specifically photoluminescence-detected magnetic resonance (PLDMR) to examine the spin nature of the singlet-triplet interaction in optically excited host-guest thin films. Correlating these with exciton kinetics from transient photoluminescence (trPL) yields insights on the luminescence as well as the formation, diffusion, and annihilation of triplet excitons. The findings of this study offer a more profound understanding of the triplet harvesting mechanisms in TADF emitters. Additionally, they offer guidance for host selection strategies that are intended to enhance the efficiency and stability of the devices.

Keywords: OLED; TADF; triplet excitons; Optical Spectroscopy; PLDMR