Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1265803 | Organic Electronics | 2006 | 10 Pages |
Abstract
We demonstrate reduced geminate recombination of excitons in electrophosphorescent organic light emitting devices using the green phosphor fac-tris(1-(9′,9′-dimethyl-2′-fluorenyl)pyrazolato,N,C2)iridium(III). At low phosphor doping concentrations (<20 wt.%) in a N,N′-dicarbazolyl-3,5-benzene host, transient electroluminescence spectra show no bimolecular quenching at the highest excitation densities used. At higher doping concentrations (>60 wt.%), the transient decay reflects the presence of phosphor molecular aggregates. The roll-off in external quantum efficiency at high current densities is attributed to the field-assisted dissociation of charge pairs prior to exciton formation.
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Authors
R.J. Holmes, S.R. Forrest, T. Sajoto, A. Tamayo, P.I. Djurovich, M.E. Thompson,