Molecular Engineering of Sulfur‐Bridged Polycyclic Emitters Towards Tunable TADF and RTP Electroluminescence

• Published in: Angewandte Chemie International Edition Vol. 61; no. 35; pp. e202209343 - n/a
• Main Authors: Li, Mengke, Xie, Wentao, Cai, Xinyi, Peng, Xiaomei, Liu, Kunkun, Gu, Qing, Zhou, Jiadong, Qiu, Weidong, Chen, Zijian, Gan, Yiyang, Su, Shi‐Jian
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 26.08.2022; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: Chemistry; Chemistry, Multidisciplinary; Donors (electronic); Electroluminescence; Electronic structure; Emitters; Organic Electronics; Organic light emitting diodes; Phosphorescence; Physical Sciences; Room-Temperature Phosphorescence; Science & Technology; Sulfur; Thermally Activated Delayed Fluorescence; ORGANIC EMITTERS; DESIGN; Organic Electronics; TRIPLET-STATE; Room-Temperature Phosphorescence; Electroluminescence; EXCITONS; LIGHT-EMITTING-DIODES; Thermally Activated Delayed Fluorescence; ACTIVATED DELAYED-FLUORESCENCE; Sulfur; EMISSION; HIGH-EFFICIENCY
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.202209343

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. By incorporating powerful electron‐donating sulfur atoms into isomeric pentaphene and pentacene frameworks, three highly efficient polycyclic thermally activated delayed fluorescence (TADF), room‐temperature phosphorescence (RTP), and mixed TADF/RTP molecules were developed for application in organic light‐emitting diodes.