A sterically hindered asymmetric D–A–D′ thermally activated delayed fluorescence emitter for highly efficient non-doped organic light-emitting diodes. Issue 35 (18th July 2019)

• Record Type: Journal Article
• Authors: Yang, Zhan; Mao, Zhu; Xu, Chao; Chen, Xiaojie; Zhao, Juan; Yang, Zhiyong; Zhang, Yi; Wu, William; Jiao, Shibo; Liu, Yang; Aldred, Matthew P.; Chi, Zhenguo
• Is Part Of: Chemical science. Volume 10:Issue 35(2019)
• Page Start: 8129
• Page End: 8134
• Publication Date: 2019-07-18
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c9sc01686d
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : An ortho -substituent design strategy promoting steric hindrance has afforded excellent AIE-TADF emitters, and high-efficiency TADF-OLEDs have been subsequently demonstrated. Abstract : Thermally activated delayed fluorescence (TADF) materials have opened a new chapter for high-efficiency and low-cost organic light-emitting diodes (OLEDs). Herein, we describe a novel and effective design strategy for TADF emitters which includes introducing a carbazole donor unit at the ortho -position, at which the donor and acceptor groups are spatially in close proximity to guarantee the existence of intramolecular electrostatic attraction and through-space charge transfer, leading to reduced structural vibrations, suppressed non-radiative decay and rapid radiative decay to avoid excited state energy loss. As a result, a green TADF emitter (2Cz-DPS ) showing high solid-state photoluminescence quantum efficiency (91.9%) and excellent OLED performance was produced. Theoretical simulations reveal that the non-adiabatic coupling accelerates the reverse intersystem crossing of2Cz-DPS, resulting in a state-of-the-art non-doped OLED with an extremely high external quantum efficiency of 28.7%.