Regnat, MarkusPernstich, Kurt P.Ruhstaller, Beat2019-06-182019-06-182019-06-182019-07-0110.1016/j.orgel.2019.04.027https://infoscience.epfl.ch/handle/20.500.14299/157271WOS:000467701400030We present an electro-optical model of a three-layer phosphorescent OLED which accurately describes the measured current efficiency and transient electroluminescence decay for different biases. Central findings are a bias-dependent emission zone, which influences light outcoupling as well as exciton quenching, and the presence of strong triplet-polaron quenching even at low bias. The measured current efficiency initially increases up to 9 V before it decreases, where the increase is found to be caused by reduced triplet-polaron quenching with holes, while the decrease is caused by a reduced light outcoupling and increased triplet-triplet annihilation. The numerical model allows identifying the individual contributions of the exciton continuity equation and explains the electroluminescence decay, which deviates significantly from a mono-exponential decay due to the dominating influence of exciton generation and quenching after the external bias is removed.Materials Science, MultidisciplinaryPhysics, AppliedMaterials SciencePhysicsoledelectro-optical device modelemission zone shiftlight outcoupling factorexciton quenchingefficiency roll-offlight-emitting-diodesexternal quantum efficiencydelayed-fluorescencecarrier mobilityphosphorescenttext::journal::journal article::research article