High-Efficiency Circularly Polarized Electroluminescence from TADF-Sensitized Fluorescent Enantiomers

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 7.8×107 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 gEL values of +1.8×10−3 and −1.4×10−3, but also display fast start-up featuring with low VT 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.