Bright and Efficient, Non-Doped, Phosphorescent Organic Red-Light-Emitting Diodes

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

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Author(s)

  • Yi-Hwa Song
  • Shi-Jay Yeh
  • Chin-Ti Chen
  • Chao-Shiuan Liu
  • Jen-Kan Yu
  • Ya-Hui Hu
  • Pi-Tai Chou
  • Shie-Ming Peng
  • Gene-Hsiang Lee

Detail(s)

Original languageEnglish
Pages (from-to)1221-1226
Journal / PublicationAdvanced Functional Materials
Volume14
Issue number12
Online published17 Nov 2004
Publication statusPublished - Dec 2004
Externally publishedYes

Abstract

Ir(III) metal complexes with formula [(nazo)2Ir(Fppz) ] (1), [(nazo)2Ir(Bppz)] (2), and [(nazo)2Ir(Fptz)] (3) [(nazo)H = 4-phenyl quinazoline, (Fppz)H = 3-trifluoromethyl-5-(2-pyridyl) pyrazole, (Bppz)H = 3-t-butyl-5-(2-pyridyl) pyrazole, and (Fptz)H = 3-trifluoromethyl-5-(2-pyridyl) triazole] were synthesized, among which the exact configuration of 1 was confirmed using single-crystal X-ray diffraction analysis. These complexes exhibited bright red phosphorescence with relatively short lifetimes of 0.4-1.05 μs in both solution and the solid-state at room temperature. Non-doped organic light-emitting diodes (OLEDs) were fabricated using complexes 1 and 2 in the absence of a host matrix. Saturated red electroluminescence was observed at λmax = 626 nm (host-emitter complex 1) and 652 nm (host-emitter complex 2), which corresponds to coordinates (0.66,0.34) and (0.69,0.31), respectively, on the 1931 Commission Internationale de 1'Eclairage (CIE) chromaticity diagram. The non-doped devices employing complex 1 showed electroluminance as high as 5780 cd m-2, an external quantum efficiency of 5.5% at 8 V, and a current density of 20 mA cm-2. The short phosphorescence lifetime of 1 in the solid state, coupled with its modest π-π stacking interactions, appear to be the determining factors for its unusual success as a non-doped host-emitter.

Citation Format(s)

Bright and Efficient, Non-Doped, Phosphorescent Organic Red-Light-Emitting Diodes. / Song, Yi-Hwa; Yeh, Shi-Jay; Chen, Chin-Ti; Chi, Yun; Liu, Chao-Shiuan; Yu, Jen-Kan; Hu, Ya-Hui; Chou, Pi-Tai; Peng, Shie-Ming; Lee, Gene-Hsiang.

In: Advanced Functional Materials, Vol. 14, No. 12, 12.2004, p. 1221-1226.

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