Orientation control of linear-shaped molecules in vacuum-deposited organic amorphous films and its effect on carrier mobilities

Daisuke Yokohama, Yousuke Setoguchi, Akio Sakaguchi, Michio Suzuki, Chihaya Adachi

Research output: Contribution to journalArticle

106 Citations (Scopus)

Abstract

The molecular orientation of linear-shaped molecules in organic amorphous films is demonstrated to be controllable by the substrate temperature. It is also shown that the molecular orientation affects the charge-transport characteristics of the films. Although linear-shaped 4,4′-bis[(N- carbazole)styryl]biphenyl molecules deposited on substrates at room temperature are horizontally oriented in amorphous films, their orientation when deposited on heated substrates with smooth surfaces becomes more random as the substrate temperature increases, even at temperatures under the glass transition temperature. Another factor dominating the orientation of the molecules deposited on heated substrates is the surface roughness of the substrate. Lower carrier mobilities are observed in films composed of randomly oriented molecules, demonstrating the significant effect of a horizontal molecular orientation on the charge-transport characteristics of organic amorphous films.

Original languageEnglish
Pages (from-to)386-391
Number of pages6
JournalAdvanced Functional Materials
Volume20
Issue number3
DOIs
Publication statusPublished - Feb 8 2010

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All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

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