https://scholars.lib.ntu.edu.tw/handle/123456789/323194
標題: | Orange and red organic light-emitting devices employing neutral Ru(II) emitters: Rational design and prospects for color tuning | 作者: | Tung, Y.-L. Chen, L.-S. Chi, Y. Chou, P.-T. Cheng, Y.-M. Li, E.Y. Lee, G.-H. Shu, C.-F. Wu, F.-I. Carty, A.J. PI-TAI CHOU |
公開日期: | 2006 | 卷: | 16 | 期: | 12 | 起(迄)頁: | 1615-1626 | 來源出版物: | Advanced Functional Materials | 摘要: | A new series of charge-neutral Ru(II) pyridyl and isoquinoline pyrazolate complexes, [Ru(bppz)2(PPh2Me)2] (bbpz: 3-tert-butyl-5-pyridyl pyrazolate) (1), [Ru(fppz)2(PPh 2Me)2] (fppz: 3-trifluoromethyl-5-pyridyl pyrazolate) (2), [Ru(ibpz)2(PPhMe2)2] (ibpz: 3-tert-butyl-5-(1-isoquinolyl) pyrazolate) (3), [Ru(ibpz)2(PPh 2Me)2] (4), [Ru(ifpz)2(PPh2Me) 2] (ifpz: 3-trifluoromethyl-5-(1-isoquinolyl) pyrazolate) (5), [Ru(ibpz)2(dpp=)] (dpp= represents cis-1,2-bis-(diphenylphosphino) ethene) (6), and [Ru(ifpz)2(dpp=)] (7), have been synthesized, and their structural, electrochemical, and photophysical properties have been characterized. A comprehensive time-dependant density functional theory (TDDFT) approach has been used to assign the observed electronic transitions to specific frontier orbital configurations. A multilayer organic light-emitting device (OLED) using 24 wt % of 5 as the dopant emitter in a 4,4′-N,N′- dicarbazolyl-1,1′-biphenyl (CBP) host with 4,4′-bis[N-(1-naphthyl)- N-phenylamino]biphenyl (NPB) as the hole-transport layer exhibits saturated red emission with an external quantum efficiency (EQE) of 5.10%, luminous efficiency of 5.74 cd A-1, and power efficiency of 2.62 lm W-1. The incorporation of a thin layer of poly(styrene sulfonate)-doped poly(3,4-ethylenedioxythiophene) (PEDOT) between indium tin oxide (ITO) and NPB gave anoptimized device with an EQE of 7.03%, luminous efficiency of 8.02 cd A-1, and power efficiency of 2.74 lm W-1 at 20 mAcm -2. These values represent a breakthrough in the field of OLEDs using less expensive Ru(II) metal complexes. The nonionic nature of the complexes as well as their high emission quantum efficiencies and short radiative lifetimes are believed to be the key factors enabling this unprecedented achievement. The prospects for color tuning based on Ru(II) complexes are also discussed in light of some theoretical calculations. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA. |
URI: | http://www.scopus.com/inward/record.url?eid=2-s2.0-33747611683&partnerID=MN8TOARS http://scholars.lib.ntu.edu.tw/handle/123456789/323194 |
DOI: | 10.1002/adfm.200500901 | SDG/關鍵字: | Energy efficiency; Isomers; Light emitting diodes; Multilayers; Optical properties; Probability density function; Quantum electronics; Ruthenium compounds; Tuning; Electronic transitions; Luminous efficiency; Photophysical properties; Time dependant density functional theory (TDDFT); Semiconducting organic compounds |
顯示於: | 化學系 |
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