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.
Original language | English (US) |
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Pages (from-to) | 163-172 |
Number of pages | 10 |
Journal | Organic Electronics |
Volume | 7 |
Issue number | 3 |
DOIs | |
State | Published - Jun 2006 |
Externally published | Yes |
Bibliographical note
Funding Information:This work was partially supported by the Air Force Office of Scientific Research, the Department of Energy Solid State Lighting Program, and Universal Display Corporation.
Keywords
- Exciton quenching
- Organic light emitting devices
- Phosphorescence