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Indexed by:期刊论文

Date of Publication:2012-01-28

Journal:JOURNAL OF MATERIALS CHEMISTRY

Included Journals:Scopus、SCIE、EI

Volume:22

Issue:4

Page Number:1411-1417

ISSN No.:0959-9428

Abstract:Two homoleptic and heteroleptic cyclometalated iridium complexes containing the 2-phenylbenzothiozole derivative as the main ligand, 1 and 2, have been synthesized and characterized as efficient orange-red phosphors. Triarylamine was introduced as an important substituent into the 6-position of the benzothiazole ring to tune the photonic and electronic properties of these complexes. Different from most of small molecular iridium complexes, 1 and 2 are solution-processable and their neat films can be obtained by a spin-coating method. Furthermore, their homogeneously dispersed films in a small molecular matrix, 4,4'-N,N'-dicarbazolebiphenyl (CBP), were successfully prepared by solution method even with low doping levels. Organic light-emitting diodes (OLEDs) were fabricated by solution processing the emitting layer containing 1 and 2 as doped emitters in the CBP host. Efficient orange-red electroluminescence by using 5 wt% 2 as the dopant was realized with a maximum efficiency of 14.49 cd A(-1) (7.38 lm W-1 and 8.73%) and Commission Internationale de l'Eclairage (CIE) coordinates of (0.60, 0.40), which are among the highest luminance efficiency ever reported for partially solution-processed red and orange-red OLEDs so far. In addition, two-element white OLEDs were achieved with these orange-red phosphors and the traditional blue emitter by spin coating the emission layer. A maximum luminance efficiency of 8.97 cd A(-1) and CIE of (0.33, 0.35) were realized.