1,8-Naphthalimide-based circularly polarized TADF enantiomers as the emitters for efficient orange-red OLEDs

The construction of new and efficient chiral TADF materials with red emission and the exploration of their applications in OLED devices still remain a great challenge for the difficulty in molecular design and low efficiency of devices. In this work, we synthesized a couple of 1,8-naphthalimide-based enantiomers (−)-(R,R)-CAI-DMAC and (+)-(S,S)-CAI-DMAC. The enantiomers not only exhibit high thermal stability with decomposition temperature of 405 °C, excellent electrochemical properties, and good thermally activated delayed fluorescence (TADF) properties with small ΔEST of 0.07 eV, but also show obvious mirror-image circular dichroism and circularly polarized luminescence properties. Moreover, by using (−)-(R,R)-CAI-DMAC and (+)-(S,S)-CAI-DMAC as emitters, the OLEDs with the bands both centred at 592 nm achieved high maximum external quantum efficiency of 12.4% and 12.3%, respectively.