Solution-processable iridium complexes for efficient orange-red and white organic light-emitting diodes

Renjie Wang, Di Liu, Run Zhang, Lijun Deng, Jiuyan Li*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

70 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)1411-1417
Number of pages7
JournalJournal of Materials Chemistry
Volume22
Issue number4
DOIs
Publication statusPublished - 28 Jan 2012

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