Chiral TADF Polymers Realizing Highly-Efficient Deep-Red Circularly Polarized Electroluminescence Over 660 nm

Circularly polarized electroluminescence (CPEL) from thermally activated delayed fluorescence (TADF) emitters have been widely reported in recent years. However, a universal strategy for designing deep-red chiral TADF emitters is still unexplored. Herein, to address the problem, a pair of chiral donor intermediates are designed and synthesized for preparing deep-red chiral TADF emitters, and two novel chiral TADF polymers R-P and S-P are developed through this strategy. The polymers exhibit intense mirror-image circularly polarized luminescence (CPL) signals in toluene dilute solution. Besides, a series of solution-processed circularly polarized polymer light-emitting diode (CP-PLED) devices are fabricated with R-P and S-P. The corresponding devices achieve persuasive performance with external quantum efficiencies (EQEs) of 6.2% and 5.8% at the wavelength of 662 nm, respectively. Besides, mirror-image CPEL signals are detected with electroluminescence dissymmetry factors (gEL) of +1.6 x 10(-3) and -1.7 x 10(-3) from the corresponding CP-PLED devices, respectively.