A novel twisted Donor-Acceptor structures with cyano substituents for advancements in Near-Infrared Red TADF Emitters

The designing and development of near-infrared (NIR) red emitters have attracted significant attention owing to the challenges of achieving the necessary energy levels for harvesting both singlet and triplet excitons and their unique requirements for this spectral range. Herein, we have reported the designing and synthesis of two novel red TADF emitters 4,4'-(3,6-bis(9,9-dimethylacridin-10(9H)-yl)dibenzo[a,c]phenazine-11,12-diyl)dibenzonitrile (Ac-PhCNDBPZ) and 4,4'-(3,6-di(10H-phenoxazin-10-yl)dibenzo[a,c]phenazine-11,12-diyl)dibenzonitrile (PXZ-PhCNDBPZ) having twisted donor-acceptor structures. A cyano substituent helps to increase the wavelength towards the redshift. These emitters show near-IR emissions at 602 and 698 nm. This work proves that the cyano substituent and rigid acceptor with a strong donor could be an effective approach to exploring high-efficiency red near-infrared TADF materials.