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Storage of charge carriers on emitter molecules in organic light-emitting diodes

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Show simple item record Reineke, Sebastian Weichsel, Caroline Burtone, Lorenzo Hintschich, Susanne I. Gather, Malte C. Leo, Karl Lüssem, Björn 2012-10-26T15:45:52Z 2012-10-26T15:45:52Z 2012-08 2012-06
dc.identifier.issn 1098-0121
dc.identifier.issn 1550-235X
dc.description.abstract Organic light-emitting diodes (OLEDs) using the red phosphorescent emitter iridium(III)bis(2-methyldibenzo[f,h]quinoxaline) (acetylacetonate) [Ir(MDQ)[subscript 2](acac)] are studied by time-resolved electroluminescence measurements. A transient overshoot after voltage turn-off is found, which is attributed to electron accumulation on Ir(MDQ)[subscript 2](acac) molecules. The mechanism is verified via impedance spectroscopy and by application of positive and negative off-voltages. We calculate the density of accumulated electrons and find that it scales linearly with the doping concentration of the emitter. Using thin quenching layers, we locate the position of the emission zone during normal OLED operation and after voltage turn-off. In addition, the transient overshoot is also observed in three-color white-emitting OLEDs. By time- and spectrally resolved measurements using a streak camera, we directly attribute the overshoot to electron accumulation on Ir(MDQ)[subscript 2](acac). We propose that similar processes are present in many state-of-the-art OLEDs and believe that the quantification of charge carrier storage will help to improve the efficiency of OLEDs. en_US
dc.description.sponsorship Germany. Federal Ministry of Education and Research (BMBF) (Contract 13N11060 R2Flex) en_US
dc.language.iso en_US
dc.publisher American Physical Society en_US
dc.relation.isversionof en_US
dc.rights Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. en_US
dc.source APS en_US
dc.title Storage of charge carriers on emitter molecules in organic light-emitting diodes en_US
dc.type Article en_US
dc.identifier.citation Weichsel, Caroline et al. “Storage of Charge Carriers on Emitter Molecules in Organic Light-emitting Diodes.” Physical Review B 86.7 (2012). ©2012 American Physical Society en_US
dc.contributor.department Massachusetts Institute of Technology. Research Laboratory of Electronics en_US
dc.contributor.mitauthor Reineke, Sebastian
dc.relation.journal Physical Review B en_US
dc.identifier.mitlicense PUBLISHER_POLICY en_US
dc.eprint.version Final published version en_US
dc.type.uri en_US
eprint.status en_US
dspace.orderedauthors Weichsel, Caroline; Burtone, Lorenzo; Reineke, Sebastian; Hintschich, Susanne; Gather, Malte; Leo, Karl; Lüssem, Björn en

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