Organic two-layer light-emitting diodes based on high-Tg hole-transporting polymers with different redox potentials

Erika Bellmann, Sean E. Shaheen, Robert H. Grubbs, Seth R. Marder, Bernard Kippelen, Nasser Peyghambarian

Research output: Contribution to journalArticle

130 Scopus citations

Abstract

A series of soluble arylamine-based hole-transporting polymers with glass transition temperatures in the range of 130-150°C have been synthesized. The synthetic methodology allows facile substitution of the aryl groups on the amine with electron-withdrawing and electron-donating moieties, which permits tuning of the redox potential of the polymer. These polymers have been used as hole-transport layers (HTLs) in two-layer light-emitting diodes ITO/HTL/Alq/Mg [ITO = indium tin oxide, Alq = tris(8-quinolinato)aluminum]. The maximum external quantum efficiency of the device increases if the redox potential of the HTL is increased to facilitate reduction of the positive charge carriers at the HTL/Alq interface. A fluorinated hole-transport polymer with a relatively large redox potential (390 mV vs ferrocenium/ferrocene) yielded the device with the highest external quantum efficiency of 1.25% photons/e-. The device stability, however, follows the opposite trend. The device with the most electron-rich HTL exhibited the best performance after prolonged usage.

Original languageEnglish (US)
Pages (from-to)399-407
Number of pages9
JournalChemistry of Materials
Volume11
Issue number2
DOIs
StatePublished - Jan 1 1999

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

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