Visible and near-infrared electrochromic properties of polymers based on triphenylamine derivatives with acceptor groups

A series of triphenylamine derivatives containing acceptor groups, including TPA-CHO, TPA-E2CN, TPA-2T-CHO, TPA-2T-E2CN, TPA-2EDOT-CHO, and TPA-2EDOT-E2CN, was synthesized, and their corresponding polymers were prepared. The polymer films exhibited reversible color changes upon electrochemical doping and dedoping. Among them, P(TPA-2T-CHO) and P(TPA-2EDOT-CHO) films showed reversible color changes from yellow to black and from green to blue, respectively. These polymer films had moderate optical contrasts in visible region and high optical contrasts in the near-infrared region. The optical contrasts of P(TPA-2T-CHO) and P(TPA-2EDOT-E2CN) films were 42.8% and 37.7% at 647 nm, and reached 81.8% and 75.6% at 1000 nm, respectively. Furthermore, these polymer films showed reasonable response times and redox stabilities upon electrochemical doping and dedoping.