Doping-free tandem white organic light-emitting diodes

Baiquan Liu; Lei Wang; Hong Tao; Miao Xu; Jianhua Zou; Honglong Ning; Junbiao Peng; Yong Cao

doi:10.1016/j.scib.2017.08.021

Doping-free tandem white organic light-emitting diodes

Sci Bull (Beijing). 2017 Sep 15;62(17):1193-1200. doi: 10.1016/j.scib.2017.08.021. Epub 2017 Aug 19.

Authors

Baiquan Liu¹, Lei Wang¹, Hong Tao¹, Miao Xu¹, Jianhua Zou², Honglong Ning¹, Junbiao Peng³, Yong Cao¹

Affiliations

¹ Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China.
² Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China. Electronic address: zou1007@gmail.com.
³ Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China. Electronic address: psjbpeng@scut.edu.cn.

PMID: 36659513
DOI: 10.1016/j.scib.2017.08.021

Abstract

Tandem white organic light-emitting diodes (WOLEDs) are of great research interest since they can greatly boost the performance compared with the single-unit counterparts. However, their structures are more complicated than those of single-unit OLEDs. Besides, to achieve high performance, the doping technology is required to tandem OLEDs, particularly for tandem WOLEDs, further complicating the structures. Herein, doping-free tandem WOLEDs, for the first time, have been demonstrated. By managing an effective doping-free charge generation layer to interconnect doping-free emitting layers/charge transport layers, high-performance doping-free tandem WOLEDs have been developed. The blue-yellow device accomplishes the simplified structure/short fabrication time/reduced cost/high efficiency/low efficiency roll-off/low voltage/high luminance trade-off, which cannot be achieved by previous tandem WOLEDs. Remarkably, the efficiency (81.2cdA^-1) is ∼2-fold higher than the highest efficiency of previous doping-free WOLEDs and even higher than those of some best doping tandem WOLEDs. The maximum luminance is 44,886cdm^-2, which is the highest for doping-free WOLEDs. Besides, the blue-red device can exhibit a color rendering index (CRI) of 67, which is even higher than that of some representative three-color tandem WOLEDs. Such findings may not only represent a significant step for doping-free WOLEDs, but unlock a novel avenue that doping-free tandem WOLEDs are promising to achieve the simplicity and high performance trade-off.

Keywords: Doping-free; Efficiency; Organic light-emitting diodes; Tandem; White.