Highly efficient white-electrophosphorescent devices based on polyfluorene copolymers containing charge-transporting pendent units

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

  • Fang-Iy Wu
  • Ping-I Shih
  • Ya-Hsien Tseng
  • Ching-Fong Shu
  • Yung-Liang Tung

Detail(s)

Original languageEnglish
Pages (from-to)167-173
Journal / PublicationJournal of Materials Chemistry
Volume17
Issue number2
Online published9 Oct 2006
Publication statusPublished - 2007
Externally publishedYes

Abstract

We have developed an efficient green-emitting polymer (FTO-BT5) through the incorporation of low-bandgap 2,1,3-benzothiadiazole (BT) moieties into the backbone of a blue-light-emitting polyfluorene copolymer (PF-TPA-OXD), which contains hole-transporting triphenylamine (TPA) and electron-transporting oxadiazole (OXD) pendent groups. A polymer light-emitting device based on this BT-containing copolymer exhibited very bright green emission having Commission Internationale d'Énclairage (CIE) chromaticity coordinates (0.32, 0.61); the maximum brightness was 10232 cd m-2 and the maximum luminance efficiency was 8.9 cd A-1. In addition, a highly efficient three-band white-light-emitting diode was prepared using PF-TPA-OXD as a blue-light-emitting host doped with this green-light-emitting FTO-BT5 copolymer and a red-light-emitting Os phosphor Os(fppz). Without co-doping any other electron- and/or hole-transporting molecules, this white-light-emitting device reached a maximum external quantum efficiency of 4.1% (8.3 cd A-1) at a luminance of 402 cd m-2 and a current density of 4.8 mA cm-2. When the luminance increased from 26 cd m-2 (0.36, 0.32) to 5258 cd m-2 (0.33, 0.31), the corresponding CIE chromaticity coordinates remain almost unaltered and very close to the emission of pure white light; the value of ηext remained above 3% in this high-luminance region.

Citation Format(s)

Highly efficient white-electrophosphorescent devices based on polyfluorene copolymers containing charge-transporting pendent units. / Wu, Fang-Iy; Shih, Ping-I; Tseng, Ya-Hsien; Shu, Ching-Fong; Tung, Yung-Liang; Chi, Yun.

In: Journal of Materials Chemistry, Vol. 17, No. 2, 2007, p. 167-173.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review