π-Bridge mediated coupling between inter-and intra-molecular charge transfer in aggregates for highly efficient near-infrared emission  

作　　者：Jingyi Xu Jie Xue Yu Dai Jinyuan Zhang Jiajun Ren Chengyu Yao Shaman Li Qingyu Meng Xueliang Wen Haoyun Shao Juan Qiao 

机构地区：[1]Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education,Department of Chemistry,Tsinghua University,Beijing,China [2]Beijing National Laboratory for Molecular Sciences,CAS Key Laboratory of Organic Solids,Institute of Chemistry,Chinese Academy of Sciences,Beijing,China [3]Key Laboratory of Theoretical and Computational Photochemistry,College of Chemistry,Ministry of Education,Beijing Normal University,Beijing,China [4]Laboratory for Flexible Electronics Technology,Tsinghua University,Beijing,China

出　　处：《Aggregate》2024年第6期340-351,共12页聚集体(英文)

基　　金：National Key R&D Program of China,Grant/Award Number:2020YFA0715000;National Natural Science Foundation of China,Grant/Award Number:51773109。

摘　　要：Intermolecular charge transfer(inter-CT)is commonly considered to quench luminescence in molecular aggregates,especially for near-infrared(NIR)emission.Herein,by elaborate comparison ofπ-bridge effects in donor/acceptor(D/A)molecules,it is disclosed that aπ-bridge is essential in D/A molecule to involve inter-CT in aggregates for inducing desired thermally activated delayed fluorescence(TADF)and largely suppressing non-radiative decays,and importantly,electrondonatingπ-bridge is critical to maximize radiative decay for inter-CT dominated emission by effective electronic coupling with bright intramolecular charge transfer(intra-CT)for high-efficiency NIR emission.As a proof-of-concept,TPATAP with thienyl asπ-bridge realized prominent photoluminescence quantum yields of 18.9%at 788 nm in solid films,and achieved record-high maximum external quantum efficiencies of 4.53%at 785 nm in devices.These findings provide fresh insight into interplay between inter-CT and intra-CT in molecular aggregates and open a new avenue to attenuate the limitation of energy gap law for developing highly efficient NIR emitters and improving the luminescent efficiency of various inter-CT systems,such as organic photovoltaic,organic long persistent luminescence,etc.

关 键 词：intermolecular charge transfer molecular aggregates near-infrared emission organic light-emitting diodes thermally activated delayed fluorescence 

分 类 号：O62[理学—有机化学]