High-efficiency organic electrophosphorescent devices with tris(2-phenylpyridine)iridium doped into electron-transporting materials

Chihaya Adachi, Marc A. Baldo, Stephen R. Forrest, Mark E. Thompson

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We demonstrate high-efficiency organic light-emitting devices employing the green electrophosphorescent molecule, fac tris(2-phenylpyridine)iridium [Ir(ppy)3], doped into various electron-transport layer (ETL) hosts. Using 3-phenyl-4-(1′-naphthyl)-5-phenyl-1,2,4-triazole as the host, a maximum external quantum efficiency (ηext) of 15.4±0.2% and a luminous power efficiency of 40±2 Im/W are achieved. We show that very high internal quantum efficiencies (approaching 100%) are achieved for organic phosphors with low photoluminescence efficiencies due to fundamental differences in the relationship between electroluminescence from triplet and singlet excitons. Based on the performance characteristics of single and double heterostructures, we conclude that exciton formation in Ir(ppy)3 occurs within close proximity to the hole-transport layer/ ETL:Ir(ppy)3 interface.

Original languageEnglish
Pages (from-to)904-906
Number of pages3
JournalApplied Physics Letters
Issue number6
Publication statusPublished - Aug 7 2000
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)

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