High-efficiency red electrophosphorescence devices

Chihaya Adachi, Marc A. Baldo, Stephen R. Forrest, Sergey Lamansky, Mark E. Thompson, Raymond C. Kwong

Research output: Contribution to journalArticle

701 Citations (Scopus)

Abstract

We demonstrate high-efficiency red electrophosphorescent organic light-emitting devices employing bis(2-(2′-benzo[4,5-a]thienyl)pyridinato-N,C3′) iridium(acetylacetonate) [Btp2Ir(acac)] as a red phosphor. A maximum external quantum efficiency of ηext=(7.0±0.5)% and power efficiency of ηp = (4.6±0.5) lm/W are achieved at a current density of J=0.01 mA/cm2. At a higher current density of J=100 mA/cm2, ηext=(2.5±0.3)% and ηp=(0.56±0.05) lm/W are obtained. The electroluminescent spectrum has a maximum at a wavelength of λmax=616 nm with additional intensity peaks at λsub=670 and 745 nm. The Commission Internationale de L'Eclairage coordinates of (cursive Greek chi=0.68, y=0.32) are close to meeting video display standards. The short phosphorescence lifetime (∼4 μs) of Btp2Ir(acac) leads to a significant improvement in ηext at high currents as compared to the previously reported red phosphor, 2,3,7,8,12,13,17,18-octaethyl-12H, 23H-prophine platinum (II) PtOEP with a lifetime of ∼50 μs.

Original languageEnglish
Pages (from-to)1622-1624
Number of pages3
JournalApplied Physics Letters
Volume78
Issue number11
DOIs
Publication statusPublished - Mar 12 2001

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)

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