Reflective Property of Inorganic Electrochromic Materials

Abstract

Optical property, such as color, transmittance, reflectance and emissivity, of electrochromic materials can be changed reversibly under low applied voltages. Electrochromic materials have a wide range of regulatable spectrum, which can realize the broadband control from the visible to mid-far-infrared. Electrochromic materials show a wide application prospect in the fields of intelligent window, display, anti-glare rearview mirror, intelligent thermal control, and camouflage. At present, most of researches on inorganic electrochromic materials focus mainly on transmission characteristics, but less on reflection characteristics. This is mainly because most inorganic electrochromic materials have single color and are not as easy to design as organic electrochromic materials. In recent years, through special preparation and structural design, the research on reflective properties of inorganic electrochromic materials has gradually attracted researchers' attention. Based on reflection characteristics of inorganic electrochromic materials, methods and principles of regulating the reflectance spectrum in the visible near infrared to mid-far-infrared bands are introduced, and the latest research progress is summarized. Within the visible band, reflectance spectrum control is mainly achieved by vanadium pentoxide (V2O5) and V2O5 doping, microstructure of one dimensional photonic crystal, Fabry Perot nanocavity structure and localized surface plasmon resonance (LSPR). Within the mid-to-far infrared band, electrochromic devices (ECDs) based on the molecular vibration absorption of tungsten oxide (WO3) or other electrochromic materials and related theory are designed and fabricated to regulate reflectance spectra. Finally, the practical application of inorganic electrochromic materials in future is prospected.