Doping-free tandem white organic light-emitting diodes

• 来源期刊: 科学通报（英文版）
• 年，卷（期）: 2017,（17）
• 页码范围: 1193-1200
• 页数: 8页
• 语种: 英文

摘要

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 (81.2 cd A-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 44,886 cdm-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.