Benzoylphenyltriazine as a new acceptor of donor–acceptor type thermally-activated delayed-fluorescent emitters

Abstract A new acceptor, benzoylphenyltriazine, was explored as a strong acceptor of thermally-activated delayed-fluorescent (TADF) emitters because of its high external quantum efficiency. The benzoylphenyltriazine acceptor was designed to have strong acceptor strength by modifying a well-known phenyltriazine acceptor with a weak electron-withdrawing benzoyl unit. The extra benzoyl unit strengthened the electron-accepting strength of the phenyltriazine acceptor, which improved the light emission performances of the TADF emitters. A BTrztCz molecule is a derivative of the benzoylphenyltriazine acceptor and was studied as a TADF emitter. The comparison of the BTrztCz emitter with a TrztCz emitter, derived from phenyltriazine based on the same donor, showed that benzoylphenyltriazine acceptor is superior to phenyltriazine for delayed-fluorescence characteristics. The quantum efficiency of the BTrztCz (21.4%) device is greater than that of the TrztCz (20.6%) device.