A red thermally activated delayed fluorescence emitter employing dipyridophenazine with a gradient multi-inductive effect to improve radiation efficiency. Issue 25 (19th June 2019)

• Record Type: Journal Article
• Authors: Wang, Huiqin; Zhao, Bingjie; Ma, Peng; Li, Zhe; Wang, Xinyu; Zhao, Chenxi; Fan, Xiatao; Tao, Lilin; Duan, Chunbo; Zhang, Jing; Han, Chunmiao; Chen, Guanying; Xu, Hui
• Is Part Of: Journal of materials chemistry. Volume 7:Issue 25(2019)
• Page Start: 7525
• Page End: 7530
• Publication Date: 2019-06-19
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c9tc02557j
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : Red TADF emitter o TPA-DPPZ employs dipyridophenazine with gradient multi-inductive effect as acceptor, which enhances intramolecular charge transfer and radiative transition, resulting photo- and electro-luminescence quantum yields of 75% and 18.5%. Abstract : Developing efficient red thermally activated delayed fluorescence (TADF) emitters is a real challenge due to the serious nonradiation of their low-band-gap singlet charge transfer state. Dipyridophenazine (DPPZ) (weak electron-withdrawing pyridines fused with strong electron-withdrawing phenazine) is used as an acceptor to overcome this issue. The gradient multi-inductive effect of different heterocyclic units simultaneously enhances the intramolecular charge transfer for red emission of the TADF molecule o TPA-DPPZ, and facilitates the radiative transition of its singlet charge transfer state by increasing frontier molecular orbital overlap on the electron-deficient pyrazine moiety. The 10-fold increased oscillator strength of its singlet transition results in its excellent photoluminescence and electroluminescence quantum efficiencies of ∼75% and ∼19%, accompanied by red emission peaked around 600 nm.