All-in-One plasticized Ionogel-based stretchable electrochromic devices

While all-in-one electrochromic devices (ECDs) have attracted attention for application in wearable stretchable electronics, electrochromic materials today are unstretchable, water-vulnerable, and prone to electrolyte leakage. To address this issue, water-resistive, leakage-free, transparent, and stretchable all-in-one plasticized electrochromic ionogels (pECIonogels) are prepared. The optimized pECIonogels are used to build flexible and stretchable ECDs. The fabricated ECDs exhibit high transmittance contrast (96.8% ΔT), rapid switching time (tc,90% = 7 s, tb,90% = 19 s), and high effective coloration efficiency (285.56 cm2 C−1) at 607 nm under an applied bias voltage of −1.0 V. Moreover, the flexible ECDs show good stability even upon compressive and tensile bending. A stretchable ECD was also fabricated by directly coating Ag nanowires on the pECIonogel through a water-assisted pre-strain method. The stretchable ECD at 50% tensile strain shows lower transmittance contrast (36.0% ΔT), slower coloration/bleaching switching (tc,90% = 222 s, tb,90% = 178 s), and reduced effective coloration efficiency (226.67 cm2 C−1) than the unstretched ECD. Nevertheless, the stretchable ECDs are stable in the relaxed and colored states after being stretched, twisted, and folded. Therefore, the proposed all-in-one pECIonogel-based ECDs are promising for the development of next-generation stretchable, wearable, and implantable electronics.