Efficient electrophosphorescence using a doped ambipolar conductive molecular organic thin film

Chihaya Adachi, Raymond Kwong, Stephen R. Forrest

Research output: Contribution to journalArticlepeer-review

202 Citations (Scopus)


We demonstrate a high efficiency organic electrophosphorescent device comprised of a 4,4′,4″-tris(3-methylphenylphenylamino)triphenylamine (m-MTDATA) hole transport layer and a 4,4′-N,N′-dicarbazole-biphenyl (CBP) host doped with the metallorganic phosphor, fac-tris(2-phenylpyridine)iridium (Ir(ppy)3) as the green light-emitting layer. The device exhibits peak external quantum and power efficiencies of (12.0 ± 0.6)% and (45 ± 2) lm/W, respectively, corresponding to ∼60% internal quantum efficiency. A luminance of 1850 cd/m2 is observed at a current density of 10 mA/cm2. The device operating properties are controlled by electron injection into, and transport by the CBP layer along with hole injection from m-MTDATA directly into the Ir(ppy)3 highest occupied molecular level, leading to direct carrier recombination and exciton formation on the phosphor dopant. Ambipolar conduction properties of the Ir(ppy)3:CBP layer are established by analysis of triplet-triplet annihilation, exciton formation and the luminance-current-voltage characteristics.

Original languageEnglish
Pages (from-to)37-43
Number of pages7
JournalOrganic Electronics
Issue number1
Publication statusPublished - Mar 2001
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Chemistry(all)
  • Condensed Matter Physics
  • Materials Chemistry
  • Electrical and Electronic Engineering


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