Self-healable electrochromic ion gels for low power and robust displays

Abstract

Abstract Self-healable materials have a great potential to achieve durable and sustainable wearable electronic devices due to its inherent healing abilities, where cracks and rupture from reiterative bending and/or twisting operations can be healed and the electronic functions are restored. Most of the self-healable electronic devices reported to date are mainly focused on sensor, battery, super capacitor, and transistor. Electrochromic devices are introduced in diverse applications such as smart window, information display, and sensors due to the simple device configuration and a wide variety of material choice. Developing a material that simultaneously exhibits excellent electrochromic properties and self-healing behavior is still an unmet challenge. Herein, we report a self-healable ion gel for low power and robust electrochromic device by combination of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP)/poly(N,N-dimethylacrylamide) (PDMAA)/1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][TFSI]) ion gel with ethyl viologen and ferrocene. Due to the high ion conductivity of ion gel, rapid redox response and low operating voltage of −1 V have been achieved. Moreover, the scratched EC ion gel was healed with minimal scarring and the healed device maintained transmittance contrast of ∼80% between bleached and colored states as well as the initial coloration efficiency of 74.84 cm2/C. Our results indicate that the ion gel has potential as a self-healable building block of low power and robust electrochromic displays and smart windows.