Chiral Conjugated Thermally Activated Delayed Fluorescent Polymers for Highly Efficient Circularly Polarized Polymer Light-Emitting Diodes

Two novel chiral conjugated polymers and designed and synthesized from a pair of circularly polarized thermally activated delayed fluorescence (CP-TADF) enantiomers are presented in this work. The two polymers exhibited excellent TADF properties with small singlet-triplet energy gaps (Δ ) of 0.045 and 0.061 eV and relatively high photoluminescence quantum yields (PLQYs) of 72 and 76%, respectively. Besides, intense mirror-image circularly polarized luminescence signals were detected from and in both solution and film states with dissymmetry factors (| |) of up to 1.9 × 10 . Furthermore, solution-processed circularly polarized polymer light-emitting diodes (CP-PLEDs) fabricated with and achieved high maximum external quantum efficiencies of 14.9 and 15.8% and high maximum brightness ( ) of 8940 and 12,180 cd/m with yellowish-green emission peaks at 546 and 544 nm, respectively. Moreover, intense circularly polarized electroluminescence signals with electroluminescence dissymmetry factors ( ) of -1.5 × 10 and +1.6 × 10 were detected from the CP-PLED devices fabricated with and , respectively.