Highly Efficient and Vivid-Red Phosphors Bearing 2,3-Diphenylquinoxaline Units and Their Application to Organic Light-Emitting Devices

Hiroyuki FUJII  Hidehiro SAKURAI  Kazuyasu TANI  Lisheng MAO  Kenichiro WAKISAKA  Toshikazu HIRAO  

IEICE TRANSACTIONS on Electronics   Vol.E87-C   No.12   pp.2119-2121
Publication Date: 2004/12/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section LETTER (Special Section on Recent Progress in Organic Molecular Electronics)
Category: Characterization of Organic Devices
phosphorescence,  chromaticity,  photoluminescence decay lifetime,  light-emitting device,  

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Newly designed cyclometalated iridium phosphors bearing 2,3-diphenylquinoxalines were characterized to provide highly efficient and vivid-red emitting materials for electrophosphorescent organic light-emitting devices. Excellent quantum efficiencies for photoluminescence (PL) within a range 50-79% were observed in dichloromethane solutions at room temperature. A greatly improved PL decay lifetime of 1.1 µsec was also observed in CBP coevaporated film. Luminescence peak wavelengths of the phosphors lay within a preferable range 653-675 nm in evaporated films. The most vivid-red electroluminescence with 1931 CIE chromaticity coordinates of (x=0.70, y=0.28) was successfully attained.