Influence of Br substituent position at the carbazole on spin-orbit coupling element matrix

Based on PDCz (1), eight regioisomers (2–9) were designed by changing Br substituent position at the carbazole to investigate the structure and property relationship. The calculated results indicate that simply changing the Br substituent position results in significant spin-orbital coupling (SOC) variation. The (n = 1–5) values of 3 and 7 with Br substituent at 3, 6-position and 1, 3-position are close to those of 1. The other compounds (2, 4–6, 8 and 9) have significant increase in SOC between singlet and triplet excited states. On the whole, most compounds containing Br substituent has higher SOC than the one that is not substituted. Moreover, the SOC increase is related to the Br substituent positions on the carbazole group.