Deep blue thermally activated delayed fluorescent emitters using CN-modified indolocarbazole as an acceptor and carbazole-derived donors

Deep blue thermally activated delayed fluorescent (TADF) emitters having carbazole derivatives as donors and CN-modified indolocarbazole as an acceptor were developed. Indolocarbazole moiety modified by CN was an acceptor of all the carbazole-based TADF emitters, and carbazole and t-butylcarbazole were donors combined with the CN-modified indolocarbazole. The carbazole-based TADF emitters showed a narrow emission spectrum with a less than 60 nm full width at half maximum, deep blue emission color with a y color coordinate below 0.13, and a high external quantum efficiency of 16.0%.