Regensburg 2019 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 57: Organic Electronics and Photovoltaics IV - Excitonic Properties and Light-Emitting Devices
CPP 57.5: Vortrag
Donnerstag, 4. April 2019, 16:00–16:15, H18
Kinetic Modelling of Transient Photoluminescence from Thermally Activated Delayed Fluorescence — •Nils Haase1,2, Andrew Danos3, Christof Pflumm2, Antonia Morherr2, Patrycja Stachelek3, Amel Mekic2,4, Wolfgang Brütting1, and Andrew P. Monkman3 — 1University of Augsburg, Augsburg, Germany — 2Merck KGaA, Darmstadt, Germany — 3Durham University, Durham, UK — 4University of Regensburg, Regensburg, Germany
Thermally activated delayed fluorescence (TADF) is an established mechanism for harvesting triplet excitons in *metal-free* OLEDs [1] which gives a maximum attainable internal quantum efficiency of 100%. By minimizing the energy gap between the lowest lying singlet and triplet states, a conversion of slowly relaxing triplet sates to faster relaxing singlet states via reverse intersystem crossing rate (rISC) is promoted. Although several highly efficient TADF emitters have been discovered, a reliable determination of the reverse intersystem crossing rate as a key parameter for the characterization of TADFs has not been provided yet. In this work, we present a kinetic model for the TADF process which allows to extract not only rate constants but also time dependent state populations from transient photolumines-cence experiments. Using this model, we obtain temperature dependent rISC rates from which we calculate the activation energy for the TADF process. [1] Uoyama et al., Nature 492 (2012), 234*238.