Extremely high-efficiency and ultrasimplified hybrid white organic light-emitting diodes exploiting double multifunctional blue emitting layers

• Published in: Light, science & applications Vol. 5; no. 8; p. e16137
• Main Authors: Liu, Bai-Quan, Wang, Lei, Gao, Dong-Yu, Zou, Jian-Hua, Ning, Hong-Long, Peng, Jun-Biao, Cao, Yong
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.08.2016; Springer Nature B.V; Nature Publishing Group
• Subjects: 639/624/1020/1091; 639/766/1130/2799; Applied and Technical Physics; Atomic; Classical and Continuum Physics; Hybridization; Lasers; Light emitting diodes; Lighting; Molecular; Optical and Plasma Physics; Optical Devices; Optics; Original; original-article; Photonics; Physics; Physics and Astronomy; efficiency roll-off; efficiency; hybrid; structure; white organic light-emitting diodes
• ISSN: 2047-7538; 2095-5545; 2047-7538
• DOI: 10.1038/lsa.2016.137

Numerous hybrid white organic light-emitting diodes (WOLEDs) have recently been developed. However, their efficiency is not comparable to that of their best all-phosphorescent WOLED counterparts, and the structures are usually complicated, restricting their further development. Herein, a novel concept is used to achieve a hybrid WOLED, whose crucial feature is the exploitation of double multifunctional blue emitting layers. The three-organic-layer WOLED exhibits a total efficiency of 89.3 and 65.1 lm W –1 at 100 and 1000 cd m –2 , respectively, making it the most efficient hybrid WOLED reported in the literature so far. Significantly, the efficiencies of hybrid WOLEDs have, for the first time, been demonstrated to be comparable to those of the best all-phosphorescent WOLEDs. In addition, the device exhibits the lowest voltages among hybrid WOLEDs (i.e., 2.4, 2.7 and 3.1 V for 1, 100 and 1000 cd m –2 , respectively). Such remarkable performance achieved from such an ultrasimplified structure opens a new path toward low-cost commercialization. White organic light-emitting diodes: simple and efficient White organic light-emitting diodes (WOLEDs) with a simplified structure and very-high efficiency could lead to low-cost commercialization. Many hybrid WOLEDs have been developed recently, but their commercialization is hindered by the relatively low efficiency complex structures. Now, Baiquan Liu of the South China University of Technology and co-workers have fabricated hybrid WOLEDs that overcome both these problems. In particular, they claim that their hybrid WOLEDs have the highest efficiency reported to date for such devices. The key to this achievement is the use of two blue emitting layers, which also serve as an electron transport layers and highly effective bridges for allowing electrons to reach an adjacent orange emitting layer. This arrangement increases the device’s efficiency by ensuring that all the excitons generated within the WOLED can be harvested for light emission.