A Tetrahedral Bisacridine Donor Enables Fast Radiative Decay in Thermally Activated Delayed Fluorescence Emitter. (16th February 2023)

• Record Type: Journal Article
• Authors: Pei, Ranran; Xu, Yulin; Miao, Jingsheng; Peng, Hao; Chen, Zhanxiang; Zhou, Changjiang; Liu, He; Yang, Chuluo
• Is Part Of: Angewandte Chemie. Volume 135:Number 13(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-02-16
• Subjects: Bisacridine -- Delocalization -- Organic Light Emitting Diodes -- Thermally Activated Delayed Fluorescence; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202217080
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: Achieving high efficiency and low efficiency roll‐off simultaneously is of great significance for further application of thermally activated delayed fluorescent (TADF) emitters. A balance between radiative decay and reversed intersystem crossing must be carefully established. Herein, we propose a qunolino‐acridine (QAc) donor composing two acridine with both planar (pAc) and bended (bAc) geometries. Combining with triazine, a TADF emitter QAc‐TRZ is assembled. The pAc provides a well interaction with triazine which ensures a decent TADF behavior, while the bAc offers a delocalization of highest occupied molecular orbital (HOMO) which guarantees an enhancement of radiative decay. Remarkably, QAc‐TRZ enables a highly efficient organic light emitting diode (OLED) with maximum external quantum efficiency (EQE) of 37.3 %. More importantly, the efficiencies under 100/1000 cd m −2 stay 36.3 % and 31.7 %, respectively, and remain 21.5 % even under 10 000 cd m −2 . Abstract : A novel bisacridine donor enables both quasi‐equatorial and quasi‐axial geometries in TADF emitter, ensuring an efficient reversed intersystem crossing and an enhanced radiative decay, which results in high‐performance OLEDs.