title: The influence of type-I and type-II triplet multiple quantum well structure on white organic light-emitting diodes.
abstract: We demonstrate high-efficient white organic light-emitting diodes (WOLEDs) based on triplet multiple quantum well (MQW) structure and focus on the influence on WOLEDs through employing different potential barrier materials to form type-I and type-II MQWs, respectively. It is found that type-I MQW structure WOLEDs based on 1,3,5-tris(N-phenyl-benzimidazol-2-yl)benzene as potential barrier layer (PBL) offers high electroluminescent (EL) performance. That is to say, maximum current efficiency and power efficiency are achieved at about 1,000 cd/m2 with 16.4 cd/A and 8.3 lm/W, which increase by 53.3% and 50.9% over traditional three-layer structure WOLEDs, respectively, and a maximum luminance of 17,700 cd/m2 is earned simultaneously. The achievement of high EL performance would be attributed to uniform distribution and better confinement of carriers within the emitting layer (EML). However, when 4,7-diphenyl-1,10-phenanthroline or 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline is used as PBL to form type-II MQW structure, poor EL performance is obtained. We attribute that to improper energy level alignment between the interface of EML/PBL, which leads to incomplete confinement and low recombination efficiency of carriers, a more detailed mechanism was argued.
authors.forename: Bo
authors.initials: B
authors.lastname: Zhao
authors.forename: Zisheng
authors.initials: Z
authors.lastname: Su
authors.affiliation: State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics, and Physics, Chinese Academy of Sciences, Changchun 130033, People's Republic of China. wllioel@aliyun.com.
authors.forename: Wenlian
authors.initials: W
authors.lastname: Li
authors.forename: Bei
authors.initials: B
authors.lastname: Chu
authors.forename: Fangming
authors.initials: F
authors.lastname: Jin
authors.forename: Xingwu
authors.initials: X
authors.lastname: Yan
authors.forename: Tianyou
authors.initials: T
authors.lastname: Zhang
authors.forename: Feng
authors.initials: F
authors.lastname: Zhang
authors.forename: Di
authors.initials: D
authors.lastname: Fan
authors.forename: Yuan
authors.initials: Y
authors.lastname: Gao
authors.forename: Junbo
authors.initials: J
authors.lastname: Wang
authors.forename: Huachun
authors.initials: H
authors.lastname: Pi
authors.forename: Jianzhuo
authors.initials: J
authors.lastname: Zhu