PEDOT has electrochromic properties, allowing it to change its absorption or color upon chemical reduction and oxidation. The oxidized state is stable and almost colorless. The reduced state is deep-blue and can be stabilized by electrolyte layers. The process of reduction and oxidation is highly reversible. The electrochemical generation of a visible contrast can be used to print simple and low-cost electrochromic displays and indicators.
Electrochromic displays and indicators have many applications such as in smart shelf labels in supermarkets, smart packaging, advertisements, greeting cards etc. When implemented in windows, they become smart and can be dimmed to adjust light transmission.