The financial support from the National Natural Science Foundation of China (NSFC, Grant No: 20672076) is gratefully acknowledged. Supporting Information is available online from Wiley InterScience or from the author.
High Performance Polymer Electrophosphorescent Devices with tert-Butyl Group Modified Iridium Complexes as Emitters†
Article first published online: 20 SEP 2007
Copyright © 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Advanced Functional Materials
Volume 17, Issue 16, pages 3319–3325, November, 2007
How to Cite
Wei, X., Peng, J., Cheng, J., Xie, M., Lu, Z., Li, C. and Cao, Y. (2007), High Performance Polymer Electrophosphorescent Devices with tert-Butyl Group Modified Iridium Complexes as Emitters. Adv. Funct. Mater., 17: 3319–3325. doi: 10.1002/adfm.200700359
- Issue published online: 29 OCT 2007
- Article first published online: 20 SEP 2007
- Manuscript Revised: 31 MAY 2007
- Manuscript Received: 28 MAR 2007
- National Natural Science Foundation of China. Grant Number: 20672076
- Iridium complexes;
- Light-emitting diodes, organic;
The synthesis and photophysical study of two novel tert-butyl modified cyclometalated iridium(III) complexes, i.e., bis(4-tert-butyl-2-phenylbenzothiozolato-N,C2′) iridium(III)(acetylacetonate) [(tbt)2Ir(acac)] and bis(4-tert-butyl-1-phenyl-1H-benzimidazolato-N,C2′) iridium(III)(acetylacetonate) [(tpbi)2Ir(acac)], are reported, their molecular structures were characterized by 13C NMR, 1H NMR, ESI-MS, FT-IR, and elementary analysis. Compared with their prototypes without tert-butyl substituents [(bt)2Ir(acac) and (pbi)2Ir(acac)], (tbt)2Ir(acac) and (tpbi)2Ir(acac) both have shortened phosphorescent lifetimes[(tbt)2Ir(acac) versus (bt)2Ir(acac), 1.1 μs:1.8 μs; (pbi)2Ir(acac) versus (tpbi)2Ir(acac), 0.8 μs:1.82 μs]. Moreover, (tbt)2Ir(acac) has much more improved phototoluminescence quantum efficiencies in CH2Cl2 solution, [(tbt)2Ir(acac), 0.51; (bt)2Ir(acac), 0.26]. Employing them as dopants, high performance double-layer PLEDs were fabricated. The (tbt)2Ir(acac)-based and (tpbi)2Ir(acac)-based PLEDs have the maximum external quantum efficiencies of 8.71 % and 10.25 %, respectively, and high EL quantum efficiencies of 5.92 % and 7.21 % can be achieved under high driven current density of 100 mA cm–2. PLEDs fabricated with both the two phosphors have much broadened EL spectra with FWHM of > 110 nm, which afford the feasibility to be used as dopants in white LEDs, and the best doping concentrations of the two complexes in fabrication of PLEDs were optimized.