Efficient, color-stable flexible white top-emitting organic light-emitting diodes

Huang

et al. 2018

Applied Sciences

Recently, exciplexes have been actively investigated in white organic light-emitting diodes (WOLEDs), since they can be effectively functioned as (i) fluorescent or thermally activated delayed fluorescent (TADF) emitters; (ii) the hosts of fluorescent, phosphorescent and TADF dopants. By virtue of the unique advantages of exciplexes, high-performance exciplex-based WOLEDs can be achieved. In this invited review, we have firstly described fundamental concepts of exciplexes and their use in organic light-emitting diodes (OLEDs). Then, we have concluded the primary strategies to develop exciplex-based WOLEDs. Specifically, we have emphasized the representative WOLEDs using exciplex emitters or hosts. In the end, we have given an outlook for the future development of exciplex-based WOLEDs.

Section: Discussionmentioning

confidence: 99%

Recent Advances of Exciplex-Based White Organic Light-Emitting Diodes

Huang

et al. 2018

Applied Sciences

“…Hence, to alleviate this difficulty, stable TADF emitters are needed to be urgently explored. Another issue for WOLEDs based on TADF required to be instantly enhanced is the color-stability, since stale color is significant to the lighting and displays [195][196][197][198][199]. However, no WOLED based on TADF has been reported to show extremely stable color [∆CIE = (0.00, 0.00)] in the whole luminance/driving voltage.…”

Section: Discussionmentioning

confidence: 99%

Emergence of White Organic Light-Emitting Diodes Based on Thermally Activated Delayed Fluorescence

Dong²,

Xie

et al. 2018

Applied Sciences

Recently, thermally activated delayed fluorescence (TADF) organic light-emitting diodes (OLEDs) have attracted both academic and industrial interest due to their extraordinary characteristics, such as high efficiency, low driving voltage, bright luminance, lower power consumption and potentially long lifetime. In this invited review, the fundamental concepts of TADF have been firstly introduced. Then, main approaches to realize WOLEDs based on TADF have been summarized. More specifically, the recent development of WOLEDs based on all TADF emitters, WOLEDs based on TADF and conventional fluorescence emitters, hybrid WOLEDs based on blue TADF and phosphorescence emitters and WOLEDs based on TADF exciplex host and phosphorescence dopants is highlighted. In particular, design strategies, device structures, working mechanisms and electroluminescent processes of the representative WOLEDs based on TADF are reviewed. Finally, challenges and opportunities for further enhancement of the performance of WOLEDs based on TADF are presented.

“…By virtue of the p-i-n technology, their device showed a CE of 23.9 cd A −1 and PE of 7.8 lm W −1 , which are one of the best for tandem fluorescent WOLEDs. However, despite the luminance and efficiency of tandem fluorescent WOLEDs can be scale linearly with the number of EL units, triplet excitons still decay nonradiatively, leading to the fact that the performance of this kind of devices is not satisfactory enough [145,146,147,148,149]. Therefore, more works are focused on phosphorescent or TADF emitters-based tandem WOLEDs.…”

Section: Stratagies For Tandem Woledsmentioning

confidence: 99%

Recent Developments in Tandem White Organic Light-Emitting Diodes

Huang

et al. 2019

Molecules

Tandem white organic light-emitting diodes (WOLEDs) are promising for the lighting and displays field since their current efficiency, external quantum efficiency and lifetime can be strikingly enhanced compared with single-unit devices. In this invited review, we have firstly described fundamental concepts of tandem device architectures and their use in WOLEDs. Then, we have summarized the state-of-the-art strategies to achieve high-performance tandem WOLEDs in recent years. Specifically, we have highlighted the developments in the four types of tandem WOLEDs (i.e., tandem fluorescent WOLEDs, tandem phosphorescent WOLEDs, tandem thermally activated delayed fluorescent WOLEDs, and tandem hybrid WOLEDs). Furthermore, we have introduced doping-free tandem WOLEDs. In the end, we have given an outlook for the future development of tandem WOLEDs.