A stretchable patch of multi-color electrochromic devices for driving integrated sensors and displaying bio-signals

We report a stretchable patch of multi-color electrochromic devices (ECDs) for powering integrated bio-sensors and visually displaying bio-signals. The fabricated ECD consists of a polyaniline cathode and an In-coated Zn anode, on transparent electrodes of Ti/Au grid, sandwiching poly(vinyl alcohol)/zinc chloride gel electrolyte in between. The ECD exhibits five colors, gray, light green, green, teal blue, and blue, depending on the applied bias voltage and shows a capacity of 64.1 mAh/m2 with a driving voltage window of 1.3 V at a current density of 0.01 mA/cm2.