Electropolymerized Triphenylamine Network Films for High‐Performance Transparent to Black Electrochromism and Capacitance

Abstract The polytriphenylamine films are prepared by electropolymerization from a precursor HPB‐6TPA with hexaphenylbenzene (HPB) core bearing six triphenylamine (TPA) units. The abundant and valuable electrochromism from transparent to black and from no to strong near‐infrared absorption are achieved from this TPA network film. The presence of residual TPA and dimeric TPA (N,N,N′,N′‐tetraphenylbenzidine) units in network film and their independent potential response attain the electrochromic behaviors. The network film possesses short response time and can realize high doping level (72%), attributed to favorable dopant ion channel caused by the twisting structure of HPB core and TPA units. The network film also shows large lightness changes and high specific capacitance (788.9 F g⁻¹@1.4 A g⁻¹), attributed to multiple active units due to HPB core with high functionality. By regulating the voltammetric cycle number of electropolymerization, films with different lightness black colored states can be prepared conveniently to satisfy different practical needs.