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

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 k(r) of 7.8x10(7) s(-1), and intense CPL activities with |g(lum)| values of about 2.5x10(-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 +1.8x10(-3) and -1.4x10(-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 EQE(max) 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.

Automated summary

Fluorescent enantiomers suitable for high-efficiency TADF-sensitized CP-OLEDs have been developed, exhibiting high PLQY, large kr values, and excellent performance characteristics. The resulting TADF-sensitized fluorescent devices show high EQE and low efficiency roll-off, providing a promising perspective for breaking through the EL efficiency limit of CP-FL emitters.