chapter  Chapter 16
29 Pages

Electrochromism And Electrochromic Devices

WithClaes G. Granqvist

This chapter reviews the basic materials background and the state of the art for electrochromic devices. Electrochromism is well known in numerous inorganic and organic substances; the chapter is devoted to the former class. The electrochromic oxide films must be permeable to ions and must show some electrical conductivity. Transmitting electrochromic devices can incorporate a thin film that serves as an ion storage. Inorganic ion conductors have been studied in several different prototype electrochromic devices. Reflectance changes have been reported in devices with bulk-type ion conductors, and transmittance as well as reflectance changes have been reported in devices with thin-film ion conductors. Electrochromic materials undergo reversible and persistent changes of their optical properties under the action of voltage pulses. Electrochromic devices can be of several different types, categorized according to the type of electrolyte or ion conductor forming the central part of the construction.