Interface control by surface-initiated deposition polymerization and its application to organic light-emitting devices

Akira Kawakami, Kiyoi Katsuki, Rigoberto C. Advincula, Kuniaki Tanaka, Kenji Ogino, Hiroaki Usui

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20 Citations (Scopus)

Abstract

Surface-initiated deposition polymerization was applied to the preparation of a hole transport layer (HTL) on an indium-tin oxide (ITO) electrode. A silane-based self-assembled monolayer (SAM) that has an azo terminal group was prepared on an ITO surface on which a vinyl monomer of carbazole (CPA) or tetraphenyldiaminobiphenyl (vTPD) was deposited by physical vapor deposition. The polymerization of the HTL was achieved by electron-assisted deposition. UV irradiation, as well as conventional evaporation, was not capable of growing polymer films on the SAM. Organic light-emitting diodes (OLEDs) were prepared by depositing tris(8-quinolinolato) aluminum (Alq3) on the HTL. The surface-initiated deposition polymerization was effective in markedly increasing device current flow and reducing turn-on voltage. However, luminescence efficiency was not improved by this method owing to improper carrier balance under excessive hole injection. Nevertheless, surface-initiated deposition polymerization was effective in improving film morphology, stability, and hole injection characteristics.

Original languageEnglish
Pages (from-to)3156-3161
Number of pages6
JournalJapanese Journal of Applied Physics
Volume47
Issue number4 PART 2
DOIs
Publication statusPublished - 2008 Apr 25
Externally publishedYes

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Keywords

  • Deposition polymerization
  • OLED
  • Organic EL
  • Organic light-emitting diode
  • SAM
  • Self-assembled monolayer
  • Surface-initiated polymerization

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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