Highly efficient green phosphorescent organic electroluminescent devices with a terbium complex as the sensitizer. (January 2017)

• Record Type: Journal Article
• Authors: Cui, Rongzhen; Liu, Weiqiang; Zhou, Liang; Li, Yanan; Jiang, Yunlong; Zhao, Xuesen; Cui, Yingjie; Zhu, Qi; Zheng, Youxuan; Deng, Ruiping; Zhang, Hongjie
• Is Part Of: Dyes and pigments. Volume 136(2017)
• Page Start: 361
• Page End: 367
• Publication Date: 2017-01
• Subjects: Electroluminescence -- Terbium complex -- Iridium complex -- Carrier trapping -- Efficiency; Dyes and dyeing -- Periodicals; Pigments -- Periodicals; 667.2
• DOI: 10.1016/j.dyepig.2016.08.068
• Languages: English
• ISSNs: 0143-7208

Abstract

Abstract: An effective device design strategy was reported to realize high performance green organic light-emitting diodes based on iridium complex by employing a trivalent terbium complex as the sensitizer. The low-lying energy levels of utilized terbium complex are beneficial in broadening recombination zone and facilitating carriers' balance on emitter molecules. No terbium ion characteristic emission was observed in co-doped devices ascribed to high triplet energy of the ligand of terbium complex. Consequently, the 0.4 wt% co-doped single light-emitting layer device obtained the maximum external quantum efficiency, current efficiency and power efficiency up to 27.6%, 114.23 cd/A and 101.92 lm/W, respectively. At 3.8 V, this device realized the practical brightness of 1000 cd/m 2 with inspiring external quantum efficiency and current efficiency as high as 27.5% and 113.71 cd/A, respectively. While the 0.2 wt% co-doped double light-emitting layers device displayed relatively lower efficiency, but higher brightness up to 205, 629 cd/m 2 . Graphical abstract: Highlights: Tb(acac)3 (phen-Cl) was utilized as sensitizer for the first time in phosphorescent OLEDs. Tb(acac)3 (phen-Cl) exhibited low-lying energy levels and high triplet energy of ligand. No Tb(III) ion emission was observed in co-doped devices. Tb(acac)3 (phen-Cl) co-doped devices obtained higher brightness, higher efficiencies and even slower efficiency roll-off.