Achieving Low-Energy Driven Viologens-Based Electrochromic Devices Utilizing Polymeric Ionic Liquids.

Herein, three kinds of viologens-based electrochromic devices (ECDs) (heptyl viologen (HV(BF)), octyl viologen (OV(BF)), and nonyl viologen (NV(BF))) were fabricated utilizing ferrocene (Fc) as a redox mediator. Among them, the NV(BF)-based ECD exhibits the highest coloration efficiency (36.2 cm/C) owing to the lowest driving energy.