New platinum(II) complexes as triplet emitters for high-efficiency monochromatic pure orange electroluminescent devices

Gui Jiang Zhou, Xing Zhu Wang, Wai Yeung Wong, Xiao Ming Yu, Hoi Sing Kwok, Zhenyang Lin

Research output: Journal article publicationJournal articleAcademic researchpeer-review

66 Citations (Scopus)

Abstract

New multi-component orange phosphorescent platinum complexes [Pt(L)(acac)] (Hacac = acetylacetone, HL = (9,9-diethyl-7-pyridin-2-ylfluoren-2-yl)diphenylamine 1, (9,9-diethyl-7-pyridin-2-ylfluoren-2-yl)di(p-tolyl)amine 2) were prepared and characterized by spectroscopic and X-ray crystallographic methods. We report the redox and photophysical properties of 1 and 2 and compare these results with the unsubstituted analogue [Pt(L)(acac)] (HL = 9,9-diethyl-2-pyridin-2-ylfluorene 3). Efficient pure orange-emitting organic light-emitting devices (OLEDs) based on 1 were fabricated. The device performance with 3,5-dicarbazolylbenzene (mCP) as the host can furnish maximium external quantum, current and power efficiencies of 4.65%, 11.75 cd/A and 5.27 lm/W at 7 V, respectively. The device with 4,4′-N,N′-dicarbazolebiphenyl (CBP) as the host can perform better with peak external quantum and current efficiencies of 6.64% and 15.41 cd/A at 7.5 V and a power efficiency of 7.07 lm/W at 6.5 V. Unlike the OLEDs made from other cyclometalated Pt(β-diketonato) complexes in which the electroluminescence spectra generally displayed both the monomeric and excimeric emissions with different relative intensities upon variation of dopant concentration, our devices emit a strong pure orange light with stable CIE color coordinates. From a steric point of view, no evidence of low-energy aggregate emission is observed for a doping level up to 12 wt.%. The present work confers a good platform for the realization of robust triplet emitters in the fabrication of highly efficient monochromatic OLEDs through the design of multifunctional chelating ligands.
Original languageEnglish
Pages (from-to)3461-3473
Number of pages13
JournalJournal of Organometallic Chemistry
Volume692
Issue number16
DOIs
Publication statusPublished - 15 Jul 2007
Externally publishedYes

Keywords

  • Arylamine
  • Crystal structures
  • Fluorene
  • Phosphorescence
  • Platinum

ASJC Scopus subject areas

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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