A novel B,O,N-doped mesogen with narrowband MR-TADF emission

Modification of an unsymmetric B,O,N-doped aromatic core with peripheral mesogenic units triggers self-assembly into a columnar hexagonal mesophase, which is stable between 22 and 144 degrees C. The columnar assembly is preserved in a glassy state below 22 degrees C. The B,O,N-doped mesogen displays narrowband sky-blue multiresonance thermally activated delayed fluorescence (MR-TADF) under diluted conditions and bright excimer emission in condensed phase. Our combined experimental and theoretical approach provides insight into the development of strongly aggregating liquid crystalline MR-TADF emitters. Modification of a MR-TADF core with mesogenic units allowed for the design a liquid crystal exhibiting narrowband sky-blue MR-TADF and self-assembly in a columnar mesophase.