Spin-assembled nanolayer of a hyperbranched polymer on the anode in organic light-emitting diodes: The mechanism of hole injection and electron blocking

Tae Woo Lee, Jong Jin Park, Young Kwon, Teruaki Hayakawa, Tae Lim Choi, Jong Hyeok Park, Rupasree Ragini Das, Masa Aki Kakimoto

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12 Citations (Scopus)


We introduced a spin-assembled nanolayer of hyperbranched poly(ether sulfone) with sulfonic acid terminal on top of an indium-tin oxide anode in organic light-emitting diodes. This results in great improvement in luminous efficiency, better than that of devices using a commercially available conducting polymer composition as a holeinjection layer. The effect of the nanolayer was investigated by impedance spectroscopy, photovoltaic measurement for built-in-potential, and transient electroluminescence. We concluded that the high luminous efficiency resulted from the efficient electron-blocking by the nanolayer and hole-injection assisted by the accumulation of electrons at the interface. This result implies that, for an efficient hole-injection layer, the electron-blocking capability should be incorporated in addition to the hole-injection and -transport capability.

Original languageEnglish
Pages (from-to)12704-12709
Number of pages6
Issue number21
Publication statusPublished - 2008 Nov 4


All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

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