High-Performance, Simplified Fluorescence and Phosphorescence Hybrid White Organic Light-Emitting Devices Allowing Complete Triplet Harvesting.
Causes of efficiency limitation in common fluorescence and phosphorescence hybrid white organic light-emitting devices (WOLEDs) are discussed, and a new device architecture is proposed to address these issues. This architecture employs a fluorescent emitting layer (EML) of blue exciplex-forming cohost, which shows broad and strong thermally activated delayed fluorescence (TADF). Hybrid WOLEDs based on this architecture not only allow complete triplet harvesting for light generation but also can achieve white light emission with high color rending indexes (CRI) using only two colors. By using 26DCzPPy:PO-T2T as the blue fluorescent EML and 26DCzPPy:Ir complexes as the phosphorescent EML, we prepared a series of two-color WOLEDs with low turn-on voltages of 2.5-3.3 V, high forward-viewing EQEs of 12.7-19.3% and high CRIs of 67-77. These results suggest this new architecture would be an effective way to achieve high performance WOLEDs with simple structures.
Center of Super-Diamond and Advanced Films (COSDAF) & Department of Physics and Materials Sciences, City University of Hong Kong , Hong Kong SAR, P.R. China.
Xiao-Ke
XK
Liu
Center of Super-Diamond and Advanced Films (COSDAF) & Department of Physics and Materials Sciences, City University of Hong Kong , Hong Kong SAR, P.R. China.
Wencheng
W
Chen
Center of Super-Diamond and Advanced Films (COSDAF) & Department of Physics and Materials Sciences, City University of Hong Kong , Hong Kong SAR, P.R. China.
Hrisheekesh
H
Thachoth Chandran
Center of Super-Diamond and Advanced Films (COSDAF) & Department of Physics and Materials Sciences, City University of Hong Kong , Hong Kong SAR, P.R. China.
Jian
J
Qing
Center of Super-Diamond and Advanced Films (COSDAF) & Department of Physics and Materials Sciences, City University of Hong Kong , Hong Kong SAR, P.R. China.
Zhan
Z
Chen
Functional Nano & Soft Materials Laboratory (FUNSOM) and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University , Suzhou, Jiangsu 215123, P.R. China.
Xiao-Hong
XH
Zhang
Center of Super-Diamond and Advanced Films (COSDAF) & Department of Physics and Materials Sciences, City University of Hong Kong , Hong Kong SAR, P.R. China.
Chun-Sing
CS
Lee
delayed fluorescence; exciplex; hybrid WOLED; phosphor; triplet harvest