Prussian‐blue‐modified electrodes: An application for a stable electrochromic display device

An electrochromic display based on a Prussian‐blue‐modified electrode is described. Prussian blues are deposited electrochemically in a solution of ferric‐ferricyanide. Current flow at +0.2 and +1.0 V is due to the reduction of Fe3+ and the oxidation of Fe2+ in the Prussian‐blue coating, respectively. The result is a display that switches from clear to blue, has high stability, and has a response of less than 100 ms.