Electrochromism is a phenomenon where a material changes color when an electric voltage is applied. This property is commonly found in certain types of polymers, oxides, and dyes. The color change occurs due to alterations in the electronic structure of the material, allowing it to absorb different wavelengths of light. Electrochromic materials are used in various applications, including smart windows that can adjust their tint based on sunlight, and displays that can change color for visual effects. This technology offers energy efficiency and enhances user comfort by controlling light and heat entering a space.