Molecular Engineering of Sulfur‐Bridged Polycyclic Emitters Towards Tunable TADF and RTP Electroluminescence
Mengke Li, Wentao Xie, Xinyi Cai, Xiaomei Peng, Kunkun Liu, Qing Gu, Jiadong Zhou, Weidong Qiu, Zijian Chen, Yiyang Gan, Shi‐Jian Su
Abstract
Abstract Highly efficient organic thermally activated delayed fluorescence (TADF) and room‐temperature phosphorescence (RTP) emitters for organic light‐emitting diodes (OLEDs) generally consist of a twisted donor–acceptor skeleton with aromatic amine donors. Herein, through introducing sulfur atoms into isomeric pentaphene and pentacene frameworks, we demonstrate a set of polycyclic luminophores exhibiting efficient TADF and RTP characters. The incorporation of sulfur atoms confirms a folded molecular plane, while intensifies singlet–triplet spin‐orbit coupling. Further, the isomeric effect has a significant effect on the electronic structure of excited state, giving rise to the investigated compounds tunable luminescence mechanisms of TADF and RTP. With efficient triplet harvesting ability, maximum external quantum efficiencies up to 25.1 % and 8.7 % are achieved for the corresponding TADF and RTP OLEDs, verifying the great potential of sulfur‐bridged frameworks for highly efficient devices.