Electrochromic–based smart windows are able to vary their throughput of visible light and solar energy by the application of an electrical voltage and are able to provide energy efficiency and comfort in buildings. The electrochromic smart windows transparency/translucidity changes reversibly due to the reduction/oxidation of the material.
An electrochromic device is essentially a researchable battery in which the electrochromic electrode is separately by a suitable electrolyte from a charge balancing counter electrode, and the color changes occur by charging and discharging the electrochemical cell with applied potential.