An Electrochromic Pure Poly(N-phenylglycine) with a High Optical Modulation Amplitude, a Wide Color Gamut, and Safe Raw Material Accessibility

Conductive polymer-based electrochromic materials (ECMs), distinguished by their wide color tunability and low cost, are limited particularly in terms of their optical modulation range and response time; meanwhile, their monomers pose significant risks to human health and the environment. In this work, we report a nontoxic polyaniline (PANI)-based derivative, poly(N-phenylglycine) (PNPG). By introducing carboxyl groups onto the nitrogen atoms of the polymer backbone, the conjugated and electronic structure of the polymer was modified, thus reducing the bandgap of PNPG and facilitating charge transportation. Therefore, PNPG demonstrates a remarkable optical modulation amplitude (85% at 778 nm) and a broad color gamut (CIE chromaticity coordinate ranges: x, 0.26-0.4; y, 0.29-0.47). Furthermore, PNPG is successfully integrated into both rigid and flexible electrochromic devices. This work offers a solution for the development of high-performance, nontoxic conductive polymers, highlighting the potential for advanced applications in smart electronics.