Management of Exciton for Highly-Efficient Hybrid White Organic Light-Emitting Diodes with a Non-Doped Blue Emissive Layer

Abstract

Hybrid white organic light-emitting diodes (WOLEDs) have drawn great attention both for display and solid-state lighting purposes because of the combined advantages of desirable stability of fluorescent dyes and high efficiency of phosphorescent materials. However, in most WOLEDs, obtaining high efficiency often requires complex device structures. Herein, we achieved high-efficiency hybrid WOLEDs using a simple but efficacious structure, which included a non-doped blue emissive layer (EML) to separate the exciton recombination zone from the light emission region. After optimization of the device structure, the WOLEDs showed a maximum power efficiency (PE), current efficiency (CE), and external quantum efficiency (EQE) of 82.3 lm/W, 70.0 cd/A, and 22.2%, respectively. Our results presented here provided a new option for promoting simple-structure hybrid WOLEDs with superior performance.

Understanding the Structure and Energy Transfer Process of Undoped Ultrathin Emitting Nanolayers Within Interface Exciplexes

“…Recently, the ultrathin emitting layer (UEML) structure shows superiority applied in simply fabricating OLEDs without the doping process. ( Zhao et al, 2011 ; Liu et al, 2014a ; Liu et al, 2014b ; Zhang et al, 2015 ; Wu et al, 2016 ; Xu et al, 2016 ; Xu et al, 2018a ; Xu et al, 2018b ; Luo et al, 2018 ; Luo et al, 2019a ). To boost the efficiency of OLEDs, an exciplex is applied due to its promoting energy transfer between the host and guest.…”