Aggregation-enhanced emission (AEE)-active polyamides with methylsulfonyltriphenylamine units for electrofluorochromic applications.

In this work, a series of AEE-active polyamides containing methylsulfonyltriphenylamine units were prepared from a newly synthesized diamine “4,4′-diamine-4″-methylsulfonyltriphenylamine” and three dicarboxylic acids, which were highly soluble in various organic solvents and exhibited outstanding thermostability. The resulting polymer films showed one reversible redox couple along with apparent color changing from colorless to purple. The polymer solutions revealed relatively weak fluorescence with quantum yields in the range of 2.2–26.2%, which could be enhanced by induced aggregation in poor solvents. Furthermore, the bright fluorescence of the solid polymer film could be reversibly tuned by direct electrochemical redox of triphenylamine with a high contrast ratio ( I off / I on ) of 234. Overall, this comprehensive investigation of their interesting electrochromic and electrofluorochromic bifunctional properties not only supplies a deep understanding of the optical essence upon electrical stimuli but also paves the way for their future intelligent applications. [ABSTRACT FROM AUTHOR]