Room-temperature phosphorescence luminophores design with enhanced spin-orbit coupling through heavy atom effect

Abstract

Herein, several room-temperature phosphoresce (RTP) compounds containing Br-substituted carbazole were designed. Br was introduced into the meta, ortho and para sites with respect to the nitrogen atom of carbazole. By performing density functional calculation, the results show that Br substitution increases the spin–orbit coupling (SOC) between the singlet and triplet excited states and enhances the intersystem crossing process. Especially, the Br-substituted compounds at ortho site increase the SOC, whereas the meta and para sites substitution have a small impact on SOC. The results highlight the prospect of using Br substitution at the ortho site in related RTP compound design.