High‐Efficiency Circularly Polarized Electroluminescence from TADF‐Sensitized Fluorescent Enantiomers. (13th August 2021)

• Record Type: Journal Article
• Authors: Li, Meng; Wang, Mei‐Ying; Wang, Yin‐Feng; Feng, Liheng; Chen, Chuan‐Feng
• Is Part Of: Angewandte Chemie. Volume 133:Number 38(2021)
• Page Start: 20896
• Page End: 20901
• Publication Date: 2021-08-13
• Subjects: circularly polarized luminescence -- electroluminescence -- fluorescent enantiomer -- organic light-emitting diode -- thermally activated delayed fluorescence sensitizer; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202108011
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: A couple of fluorescent enantiomers, which are suitable for the emitters of high‐efficiency TADF‐sensitized CP‐OLEDs, have been developed. The enantiomers show configurational stability, high PLQY of 98 %, large kr of 7.8×10 7 s −1, and intense CPL activities with |glum | values of about 2.5×10 −3 . Notably, by using matchable TADF sensitizer, the enantiomers were then exploited as emitter to fabricate CP‐OLEDs. The TADF‐sensitized CP‐OLEDs not only show mirror‐image CPEL activities with g EL values of +1.8×10 −3 and −1.4×10 −3, but also display fast start‐up featuring with low V T of 3.0 V as well as driving voltage of 4.8 V at 10 000 cd m −2 . Meaningfully, the TADF‐sensitized fluorescent devices show high EQEmax of 21.5 % and extremely low efficiency roll‐off, whose EQEs are 21.2 % and 15.3 % at 1000 and 10 000 cd m −2, respectively. The obtained EQEs are comparable to those of CP‐TADF emitters, which provides a promising perspective to break through the EL efficiency limit of CP‐FL emitters. Abstract : A couple of fluorescent enantiomers with high PLQY of 98 % and mirror‐imaged CPL activities have been developed to fabricate TADF‐sensitized CP‐OLEDs. The resulting devices not only display intense CPEL with | g EL | of about 1.8×10 −3, but also show high EQEmax of 21.5 % with remarkably low efficiency roll‐off, whose EQE is 15.3 % even at 10 000 cd m −2 .