Star-shaped conjugated systems derived from thienyl-derivatized poly(triphenylamine)s as active materials for electrochromic devices

A star-shaped molecule, tris[4-(2-thienyl)phenyl]amine, which contains triphenylamine as core and thiophene as arms, was successfully synthesized via Suzuki coupling reaction. Poly(tris[4-(2-thienyl)phenyl]amine) (PTTPA) was electrochemically synthesized and characterized. The resulting polymer film exhibited four various colors under different potentials. Moreover, the PTTPA film showed high optical contrast (38% at 430 nm, 29% at 560 nm, and 53% at 710 nm) and satisfactory response time (2.57 s at 430 nm, 0.76 s at 560 nm, and 2.10 s at 710 nm). An electrochromic device (ECD) based on PTTPA and poly(3,4-ethylenedioxythiophene) (PEDOT) was also constructed and characterized. This ECD was found to have good switching times, reasonable contrast, and satisfactory optical memories and redox stability.