Carbazole ring: A delicate rack for constructing thermally activated delayed fluorescent compounds with through-space charge transfer

Three carbazole derivatives, AcPTC, PxPTC and PtPTC, consisting of two 9,9-dimethyl-9,10-dihydroacridine, phenoxazine or phenothiazine donor groups and one diphenyltriazine acceptor group fixed at 1,8,9-positions of a single carbazole ring via phenylene, are designed and synthesized. X-ray diffraction analysis of AcPTC reveals that there exist multiple p-pinteractions between the donor and acceptor groups to form a sandwich-like structural unit with edge-to-face interaction model. The compounds thus show obvious thermally activated delayed fluorescence with through-space charge transfer character and possess considerable photoluminescence quantum yields of up to 73% in doped films with sky-blue to yellow emissions. The solution-processed electroluminescent devices achieve the highest maximum external quantum efficiencies of 10.0%, 11% and 5.6% for AcPTC, PxPTC and PtPTC, respectively, with small efficiency roll-offs. (C) 2021 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Automated summary

By designing and synthesizing different carbazole derivatives, compounds with excellent fluorescence properties have been achieved. These compounds show good quantum efficiency in electroluminescent devices and have small efficiency roll-offs.