Premium
EL Properties and Exciton Dynamics of High‐Performance Doping‐Free Hybrid WOLEDs Based on 4P‐NPD/Bepp 2 Heterojunction as Blue Emitter
Author(s) -
Chen Yuwen,
Sun Qian,
Dai Yanfeng,
Yang Dezhi,
Qiao Xianfeng,
Ma Dongge
Publication year - 2019
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.201900703
Subject(s) - common emitter , quantum efficiency , materials science , exciton , optoelectronics , electroluminescence , heterojunction , oled , doping , phosphorescence , luminance , diode , chromaticity , electrical efficiency , color rendering index , fluorescence , optics , light emitting diode , nanotechnology , power (physics) , physics , layer (electronics) , quantum mechanics
It is well known that one of the major challenges facing white organic light‐emitting diodes (WOLEDs) has been to achieve high efficiency, low efficiency roll‐off, and high color rendering index (CRI) simultaneously. A simple charge‐ and exciton‐confining emitting layer structure formed by employing a blue emitting p/n heterojunction, and combined with red, yellow, and green phosphorescent ultrathin layers, is presented, thus realizing the stable utilization of 100% excitons. The resulting hybrid WOLEDs exhibit the maximum forward‐viewing external quantum efficiency and power efficiency of 23.4% and 50.4 lm W −1 , and keep them at 20.3% and 31.2 lm W −1 at 1000 cd m −2 , showing high efficiency and low efficiency roll‐off. Furthermore, the device also shows extremely stable electroluminescent spectra in the whole luminance range with a high CRI of 93 and the Commission Internationale de L'Eclairage coordinates of (0.49, 0.43) at 1000 cd m −2 , which is perfect warm white for indoor lighting. The achievement of the excellent comprehensive performances is the best result reported to date among the conventional blue fluorescence‐based hybrid WOLEDs possessing such high CRI, which may be a new starting point for further research on high‐performance hybrid WOLEDs.