In-Plane Anisotropic Molecular Orientation of Pentafluorene and Its Application to Linearly Polarized Electroluminescence

Takeshi Komino, Hiroyuki Kuwae, Akiko Okada, Weixin Fu, Jun Mizuno, Jean Charles Maurice Ribierre, Yuji Oki, Chihaya Adachi

研究成果: ジャーナルへの寄稿記事

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By preparing parallelly aligned 1.9-μm-high SiO2 microfluidic channels on an indium tin oxide substrate surface, the solution flow direction during spin-coating was controlled to be parallel to the grating. Using this technique, a pentafluorene-4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP) binary solution in chloroform was spin-coated to embed a 40-50 nm-thick 10 wt %-pentafluorene:CBP thin film in the channels. In-plane polarized photoluminescence measurements revealed that the pentafluorene molecules tended to orient along the grating, demonstrating that one-dimensional fluid flow can control the in-plane molecular orientation. Furthermore, the dependences of the photoluminescence anisotropy on the spin speed and substrate material suggest that the velocity of the solution flow and/or its gradient in the vertical direction greatly affects the resulting orientation. This indicates that the mechanism behind the molecular orientation is related to stress such as the shear force. The effect of the solution flow on the molecular orientation was demonstrated even in organic light-emitting diodes (OLEDs). Linearly polarized electroluminescence was obtained by applying the in-plane orientation to OLEDs, and it was found that the dichroic ratio of the electroluminescence orthogonal (x) and parallel (y) to the grating is x/y = 0.75.

元の言語英語
ページ(範囲)27054-27061
ページ数8
ジャーナルACS Applied Materials and Interfaces
9
発行部数32
DOI
出版物ステータス出版済み - 8 16 2017

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All Science Journal Classification (ASJC) codes

  • Materials Science(all)

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