https://scholars.lib.ntu.edu.tw/handle/123456789/607046
標題: | An extended π-backbone for highly efficient near-infrared thermally activated delayed fluorescence with enhanced horizontal molecular orientation | 作者: | He J.-L Tang, Yukun Zhang, Kai Zhao, Yue Lin, Yu-Ching Hsu, Chih-Kai Chen, Chia-Hsun Chiu, Tien-Lung Lee, Jiun-Haw Wang, Chuan-Kui Wu, Chung-Chih Fan, Jian |
公開日期: | 2022 | 卷: | 9 | 期: | 2 | 起(迄)頁: | 772-779 | 來源出版物: | Materials horizons | 摘要: | Near-infrared thermally activated delayed fluorescence (NIR-TADF) materials with emission over 700 nm have been insufficiently investigated mainly due to the limited choice of strong donor/acceptor units for molecular construction and the limited electronic coupling between the donors and acceptors. Herein, a novel D-A1-A2-A3 configuration was developed for the design of a NIR-TADF material (TPA-CN-N4-2PY), in which three types of sub-acceptor units (CN: cyano; N4: dipyrido[3,2-a:2',3'-c]phenazine; PY: pyridine) were incorporated into a molecular skeleton to reinforce the electron-accepting strength. The attachment of two pyridine units on TPA-CN-N4 produced TPA-CN-N4-2PY with an extended π-backbone, which shifted the electroluminescence (EL) emission into the NIR region and enhanced the horizontal ratio of emitting dipole orientation (Θ//) simultaneously. TPA-CN-N4-2PY-based OLEDs demonstrated a record-high external quantum efficiency (EQE) of 21.9% with an emission peak at 712 nm and Θ// = 85% at the doping ratio of 9.0 wt%. On the contrary, the parent compound TPA-CN-N4-based OLEDs at the same doping ratio achieved an EQE of 23.4% at 678 nm with Θ// = 75%. This multiple sub-acceptors approach could enrich the design strategy of the NIR-TADF materials, and the large conjugated system could improve the Θ// for achieving efficient emitters. |
URI: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-85124437509&doi=10.1039%2fd1mh01651b&partnerID=40&md5=2e159bcc6b23c6d828abf93c19b6ea05 https://scholars.lib.ntu.edu.tw/handle/123456789/607046 |
ISSN: | 20516355 | DOI: | 10.1039/d1mh01651b |
顯示於: | 電機工程學系 |
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