登录
 机构网站
  1. 首页
  2. 情报产品
  3. 快讯详情

《Highly Efficient Organic Light-Emitting Diodes with Phosphorescent Emitters Having High Quantum Yield and Horizontal Orientation of Transition Dipole Moments》

  • 来源专题：绿色印刷—OLED
  • 编译者： 张宗鹏
  • 发布时间：2016-04-13

  • Ancillary ligands in heteroleptic iridium complexes significantly influence the orientation of the transition dipole moments. Ir(ppy)3, a homoleptic iridium complex, exhibits isotropic dipole orientation, whereas the heteroleptic Ir complexes of Ir(ppy)2tmd show a highly preferred dipole orientation (78%) in the horizontal direction. In addition, we demonstrate an unprecedented highly efficient green OLED exhibiting an EQE of 32.3% and a power efficiency of 142.5 lm/W by using an emitter with high quantum yield and horizontally oriented dipoles.

  • 原文来源：;http://onlinelibrary.wiley.com/doi/10.1002/adma.201305733/abstract
83浏览量
0点赞
收藏
原文链接
相关报告

  • 《Understanding and predicting the orientation of heteroleptic phosphors in organic light-emitting materials》
    • 来源专题：绿色印刷—LED
    • 编译者：张宗鹏
    • 发布时间：2016-04-13
    • Controlling the alignment of the emitting molecules used as dopants in organic light-emitting diodes is an effective strategy to improve the outcoupling efficiency of these devices. To explore the mechanism behind the orientation of dopants in films of organic host materials, we synthesized a coumarin-based ligand that was cyclometalated onto an iridium core to form three phosphorescent heteroleptic molecules, (bppo)2Ir(acac), (bppo)2Ir(ppy) and (ppy)2Ir(bppo) (bppo represents benzopyranopyridinone, ppy represents 2-phenylpyridinate, and acac represents acetylacetonate). Each emitter was doped into a 4,4′-bis(N-carbazolyl)-1,1′-biphenyl host layer, and the resultant orientation of their transition dipole moment vectors was measured by angle-dependent p-polarized photoluminescent emission spectroscopy. In solid films, (bppo)2Ir(acac) is found to have a largely horizontal transition dipole vector orientation relative to the substrate, whereas (ppy)2Ir(bppo) and (bppo)2Ir(ppy) are isotropic. We propose that the inherent asymmetry at the surface of the growing film promotes dopant alignment in these otherwise amorphous films. Modelling the net orientation of the transition dipole moments of these materials yields general design rules for further improving horizontal orientation.
    48浏览量
    0点赞
    收藏
    原文链接

  • 《Blue Phosphorescent Organic Light-Emitting Diodes Using an Exciplex Forming Co-host with the External Quantum Efficiency of Theoretical Limit》
    • 来源专题：绿色印刷—OLED
    • 编译者：张宗鹏
    • 发布时间：2016-04-13
    • A high-efficiency blue-emitting organic light-emitting diode (OLED) approaching theoretical efficiency using an exciplex-forming co-host composed of N,N′-dicarbazolyl-3,5-benzene (mCP) and bis-4,6-(3,5-di-3-pyridylphenyl)- 2-methylpyrimidine (B3PYMPM) is fabricated. Iridium(III)bis[(4,6-difluorophenyl)- pyridinato-N,C2′]picolinate (FIrpic) is used as the emitter, which turns out to have a preferred horizontal dipole orientation in the emitting layer. The OLED shows a maximum external quantum efficiency of 29.5% (a maximum current efficiency of 62.2 cd A−1), which is in perfect agreement with the theoretical prediction.
    125浏览量
    0点赞
    收藏
    原文链接