Multicolor Electrochromic Fibers with Helix‐Patterned Electrodes

Abstract Wearable electrochromic devices with a multiple color changing effect have shown great potential for applications in the fields of displaying, decoration, safety warning, and sensors. However, limited attention is paid toward the preparation of multicolor electrochromic fiber devices. In this study, a set of electrochromic fibers which can change their color between dark red, green, and gold is prepared. The fiber devices are prepared by forming dual helix metal electrodes along a plastic fiber substrate and by subsequently depositing tungsten oxide and poly(3‐methylthiophene) separately on the two electrodes. A solid electrolyte LiClO 4 /poly(methyl methacrylate) is used so the entire device is in the form of freestanding fiber. The reversible electrochromism is driven by a voltage between −1.5 and +1.5 V. It shows high coloration efficiency (77.82 for WO 3 and 54.41 cm 2 C −1 for poly(3‐methylthiophene)) and fast response (up to 5 s). The distributions of electrical potential and lithium ion on the device are analyzed by a finite element method. This study may provide a novel method to construct multifunctional fiber electronics.