Donor and Acceptor Fused 16,16‐Dimethyl‐11,16‐dihydrodibenzo[2,3:5,6]pyrrolizino[1,7‐ab]acridine as a Blue‐Emitting Chromophore for High External Quantum Efficiency and Long Lifetime

Abstract The rigid molecular assembly formed by the fusion of the donor type acridine and acceptor type indolo[3,2,1‐jk]carbazole, namely 16,16‐dimethyl‐11,16‐dihydrodibenzo[2,3:5,6]pyrrolizino[1,7‐ab]acridine (ACDID), is developed as a new chromophore to give narrow emission in the blue region. The functionalization of the chromophore with phenyl and triphenylamine gives two fluorescence emitters, ACDID‐Ph and ACDID‐TPA, respectively. The in‐depth study of the emitters has confirmed that the triphenylamine unit in the ACDID‐TPA emitter enhances the external quantum efficiency (EQE) along with device stability. The ACDID‐TPA emitter shows high EQE of 6.3% and small full width at half maximum of 39 nm by the rigidity of the chromophore. The ACDID‐derived blue emitter performs better than the conventional pyrene‐derived emitter in terms of device lifetime, demonstrating the potential of the donor‐ and acceptor‐fused ACDID as the chromophore of blue emitters.