A perspective on blue TADF materials based on carbazole-benzonitrile derivatives for efficient and stable OLEDs

The advent of materials with thermally activated delayed fluorescence (TADF) has triggered a wave of research to break the mutual exclusion of high efficiency and long lifetime of blue organic light-emitting diodes. Representatively, multiple donor-acceptor-type carbazole-benzonitrile (CzBN) derivatives have realized the longest device lifetimes in the blue region up to now together with high efficiencies among all TADF emitters. This perspective timely summarizes the progress of molecular design and device performances of CzBN derivatives and is concluded by providing suggestions on the future development of such materials and the corresponding devices.