TY - JOUR
T1 - Acceptor-Donor-Acceptor-Configured Delayed Fluorescence Emitters for Efficient Orange-Red and White Devices with Low Roll-off
AU - He, Yi Hui
AU - Xie, Feng Ming
AU - Zhang, Kai
AU - Yang, Dezhi
AU - Shen, Yang
AU - Li, Hao Ze
AU - Ma, Dongge
AU - Li, Yan Qing
AU - Tang, Jian Xin
N1 - Publisher Copyright:
© 2023 Wiley-VCH GmbH.
PY - 2023/10/9
Y1 - 2023/10/9
N2 - Organic light-emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) materials are promising for the realization of highly efficient emitters. However, severe efficiency roll-off at high brightness still remains as a huge challenge for TADF-based OLEDs. Herein, rod-like orange-red TADF emitters of 2BNCz-PZ and 2BNtCz-PZ with acceptor-donor-acceptor (A-D-A) configuration are developed by bearing dihydrophenazine donor and discoidal rigid boron, nitrogen-contained polycyclic aromatic hydrocarbons acceptors. Both emitters exhibit hybrid long-range/short-range charge-transfer excitation for small singlet-triplet energy splitting, short delayed lifetime, and high photoluminescence quantum yield, leading to fast singlet radiation rate over 107 s−1 and fast reverse intersystem crossing rate over 106 s−1. Furthermore, a horizontal emitting dipole orientation factor over 90% is realized. The optimized orange-red OLED based on 2BNtCz-PZ presents a maximum external quantum efficiency (EQE) of 31.0% and a slight EQE roll-off to 22.2% at 1 000 cd m−2 with emission peak over 600 nm. In addition, the single-emitting layer white OLEDs achieve a maximum EQE of 30.6% due to the use of these orange-red dopants with intense charge-transfer absorption band. This work reveals the potential of the rod-like A-D-A configuration for constructing highly efficient orange-red TADF emitters with low-efficiency roll-off.
AB - Organic light-emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) materials are promising for the realization of highly efficient emitters. However, severe efficiency roll-off at high brightness still remains as a huge challenge for TADF-based OLEDs. Herein, rod-like orange-red TADF emitters of 2BNCz-PZ and 2BNtCz-PZ with acceptor-donor-acceptor (A-D-A) configuration are developed by bearing dihydrophenazine donor and discoidal rigid boron, nitrogen-contained polycyclic aromatic hydrocarbons acceptors. Both emitters exhibit hybrid long-range/short-range charge-transfer excitation for small singlet-triplet energy splitting, short delayed lifetime, and high photoluminescence quantum yield, leading to fast singlet radiation rate over 107 s−1 and fast reverse intersystem crossing rate over 106 s−1. Furthermore, a horizontal emitting dipole orientation factor over 90% is realized. The optimized orange-red OLED based on 2BNtCz-PZ presents a maximum external quantum efficiency (EQE) of 31.0% and a slight EQE roll-off to 22.2% at 1 000 cd m−2 with emission peak over 600 nm. In addition, the single-emitting layer white OLEDs achieve a maximum EQE of 30.6% due to the use of these orange-red dopants with intense charge-transfer absorption band. This work reveals the potential of the rod-like A-D-A configuration for constructing highly efficient orange-red TADF emitters with low-efficiency roll-off.
KW - acceptor-donor-acceptor type
KW - fast up-conversion rate
KW - low efficiency roll-off
KW - orange-red electroluminescent devices
KW - thermally activated delayed fluorescence
UR - https://www.scopus.com/pages/publications/85161148941
U2 - 10.1002/adfm.202304006
DO - 10.1002/adfm.202304006
M3 - 文章
AN - SCOPUS:85161148941
SN - 1616-301X
VL - 33
JO - Advanced Functional Materials
JF - Advanced Functional Materials
IS - 41
M1 - 2304006
ER -