Highly efficient red-electrophosphorescent devices based on polyfluorene copolymers containing charge-transporting pendant 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
  • Guan-Yu Chen
  • Chen-Han Chien
  • Ching-Fong Shu
  • Yung-Liang Tung
  • Yun Chi

Detail(s)

Original languageEnglish
Pages (from-to)14000-14005
Journal / PublicationJournal of Physical Chemistry B
Volume109
Issue number29
Publication statusPublished - 28 Jul 2005
Externally publishedYes

Abstract

We have systematically examined the photoluminescence (PL) and electroluminescence (EL) behavior of blends comprising two efficient red phosphors doped, respectively, into the blue-emitting polyfluorene derivatives PF-TPA-OXD and PF-OXD. The host polymers, which contain both hole- and electron-transporting or merely electron-transporting side chains, are capable of facilitating charge injection and transport. After determining the HOMO and LUMO energy levels of these materials, we were able to match the dopant with its most suitable host to achieve the direct formation and confinement of an exciton at the dopant. This configuration also leads to a reduction in the electrical excitation of the host polymer, which in turn decreases the degree of exciton loss arising from nonradiative decay of the host triplet. Using this approach, we were able to realize the production of high-performance red-electrophosphorescent devices. For Os(fppz)-doped devices, we obtain a balanced charge recombination in conjunction with higher current and luminance when using PF-TPA-OXD as the host matrix; this device reached a maximum external quantum efficiency of 8.37% with a peak brightness of 16 720 cd/m 2. The absence of charge-transporting pendant units, i.e., the device fabricated from poly[9,9-dioctylfluorene-2,7-diyl] (POF), led, however, to relatively poor electroluminescence characteristics (5.81% and 2144 cd/m 2). © 2005 American Chemical Society.

Citation Format(s)

Highly efficient red-electrophosphorescent devices based on polyfluorene copolymers containing charge-transporting pendant units. / Wu, Fang-Iy; Shih, Ping-I.; Tseng, Ya-Hsien; Chen, Guan-Yu; Chien, Chen-Han; Shu, Ching-Fong; Tung, Yung-Liang; Chi, Yun; Jen, Alex K.-Y.

In: Journal of Physical Chemistry B, Vol. 109, No. 29, 28.07.2005, p. 14000-14005.

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