title: All solution-processed stable white quantum dot light-emitting diodes with hybrid ZnO@TiO₂ as blue emitters.
abstract: White quantum dot light-emitting diodes (QD-LEDs) have been a promising candidate for high-efficiency and color-saturated displays. However, it is challenging to integrate various QD emitters into one device and also to obtain efficient blue QDs. Here, we report a simply solution-processed white QD-LED using a hybrid ZnO@TiO₂ as electron injection layer and ZnCdSeS QD emitters. The white emission is obtained by integrating the yellow emission from QD emitters and the blue emission generated from hybrid ZnO@TiO₂ layer. We show that the performance of white QD-LEDs can be adjusted by controlling the driving force for hole transport and electroluminescence recombination region via varying the thickness of hole transport layer. The device is demonstrated with a maximum luminance of 730 cd/m(2) and power efficiency of 1.7 lm/W, exhibiting the Commission Internationale de l'Enclairage (CIE) coordinates of (0.33, 0.33). The unencapsulated white QD-LED has a long lifetime of 96 h at its initial luminance of 730 cd/m(2), primarily due to the fact that the device with hybrid ZnO@TiO₂ has low leakage current and is insensitive to the oxygen and the moisture. These results indicate that hybrid ZnO@TiO₂ provides an alternate and effective approach to achieve high-performance white QD-LEDs and also other optoelectronic devices.
authors: 1] School of Electronic Science and Engineering, Southeast University, Nanjing, China, 210096 [2].
authors: Jing
authors: J
authors: Chen
authors: 1] Department of Electrical Engineering and Computer Science, the University of Michigan, Ann Arbor, Michigan 48109, USA [2].
authors: Dewei
authors: D
authors: Zhao
authors: School of Electronic Science and Engineering, Southeast University, Nanjing, China, 210096.
authors: Chi
authors: C
authors: Li
authors: School of Electronic Science and Engineering, Southeast University, Nanjing, China, 210096.
authors: Feng
authors: F
authors: Xu
authors: School of Electronic Science and Engineering, Southeast University, Nanjing, China, 210096.
authors: Wei
authors: W
authors: Lei
authors: School of Electronic Science and Engineering, Southeast University, Nanjing, China, 210096.
authors: Litao
authors: L
authors: Sun
authors: Electrical Engineering Division, Engineering Department, University of Cambridge, 9 JJ Thomson Avenue, CB3 0FA, Cambridge, UK.
authors: Arokia
authors: A
authors: Nathan
authors: School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798.
authors: Xiao Wei
authors: XW
authors: Sun