Rational Design of Charge-Neutral, Near-Infrared-Emitting Osmium(II) Complexes and OLED Fabrication

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

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Author(s)

  • Tsang-Chi Lee
  • Jui-Yi Hung
  • Yi-Ming Cheng
  • Gene-Hsiang Lee
  • Pi-Tai Chou
  • Chung-Chia Chen
  • Chih-Hao Chang
  • Chung-Chih Wu

Detail(s)

Original languageEnglish
Pages (from-to)2639-2647
Journal / PublicationAdvanced Functional Materials
Volume19
Issue number16
Online published13 Aug 2009
Publication statusPublished - 24 Aug 2009
Externally publishedYes

Abstract

A new series of charge neutral Os(II) isoquinolyl triazolate complexes (1-4) with both tram and cis arrangement of phosphine donors are synthesized, and their structural, electrochemical and photophysical properties are established. In sharp contrast to the ris-arranged complexes 2-4, the trans derivative 1, which shows a planar arrangement of chromophoric Nsubstituted chelates, offers the most effective extended jr-delocalization and hence the lowest excited state energy gap. These complexes exhibit phosphorescence with peak wavelengths ranging from 692-805 nm in degassed CH2CI2 at room temperature. Near-infrared (NIR)-emitting electroluminescent devices employing 6wt % of 1 (or 4) doped in AIq3 host material are successfully fabricated. The devices incorporating 1 as NIR phosphor exhibit fairly intense emission with a peak wavelength at 814nm. Forward radiant emittance reaches as high as 65.02 μWcm-2, and a peak EQE of ∼ 1.5% with devices employing Alq3, TPBi and/or TAZ as electrontransporting/exciton-blocking layers. Upon switching to phosphor 4, the electroluminescence blue shifts to 718 nm, while the maximum EQE and radiance increase to 2.7% and 93.26 (μWcm -2) respectively. Their performances are optimized upon using TAZ as the electron transporting and exciton-blocking material. The OLEDs characterized represent the only NIRemitting devices fabricated using charge-neutral and volatile Os(II) phosphors via thermal vacuum deposition. 

Citation Format(s)

Rational Design of Charge-Neutral, Near-Infrared-Emitting Osmium(II) Complexes and OLED Fabrication. / Lee, Tsang-Chi; Hung, Jui-Yi; Chi, Yun; Cheng, Yi-Ming; Lee, Gene-Hsiang; Chou, Pi-Tai; Chen, Chung-Chia; Chang, Chih-Hao; Wu, Chung-Chih.

In: Advanced Functional Materials, Vol. 19, No. 16, 24.08.2009, p. 2639-2647.

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