Electrochromic materials and devices for energy efficient windows

Numerous inorganic and organic electrochromic materials are discussed in the context of developing a film-based optical shutter for a window application. It is possible electronically to alter a window's transmission and reflection properties by use of electrochromic thin films. This allows regulation of conductive and radiative heat transfer rates, with variable optical attenuation. As a result, an aperture can be optically and thermally managed, reducing space heating and cooling loads. The properties of transition metal oxides, such as WO3, MoO3, Ir2O3 and V2O5 are detailed. Organic systems such as heptyl viologen and polytungsten anion are reviewed. Also, intercalated structures are discussed. Various designs of working devices are outlined with emphasis on solid-state configurations. From this quantification, materials and devices with appropriate deposition techniques for window applications are detailed.