Dresden 2003 – scientific programme

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HL: Halbleiterphysik

HL 14: Poster I

HL 14.55: Poster

Monday, March 24, 2003, 17:00–19:30, HSZ/P2

High-efficiency electrophosphorescent organic light-emitting diodes with double doped light-emitting layers — •xiang zhou, Dashan Qin, Jan Blochwitz-Nimoth, Martin Pfeiffer, and Karl Leo — Institut fuer Angewandte Photophysik, Technische Universitaet Dresden, D-01062 Dresden, Germany, www.iapp.de

We demonstrate high efficiency electrophosphorescent organic light-emitting diodes (PHOLEDs) with double doped light-emitting layers (D-EMLs) by doping both hole and electron transport hosts with fac tris(2-phenylpyridine)iridium [Ir(ppy)3] simultaneously. [1] The D-EMLs PHOLEDs show significantly improved efficiency compared to the conventional devices with a single EML. We attribute the improvement mainly to reduced losses of triplet excitons into regions that are not doped by phosphorescent emitter molecules. More detailed mechanisms of D-EMLs PHOLEDs will be discussed. [1, 2] Moreover, the D-EMLs structures have the potential to optimize the carrier balance at the carrier-recombination interfaces and combine pin structure to further improve the device power efficiency. [3, 4] [1] X. Zhou et al., Appl. Phys. Lett. 81 (2002) 4070. [2] D. S. Qin et al., (to be submitted, 2002). [3] J. S. Huang et al., Appl. Phys. Lett. 80 (2002) 139. [4] M. Peiffer et al., Adv. Mater. (in press 2002).