*5.1.3 Infrared reflective and electrochromic coatings*

In electrochromic devices, the optical properties such as absorption, transmission, reflection and/emission can be changed when an electrical potential is applied. These devices are ubiquitous in daily life and are used as antidazzle rearview mirrors in cars as well as state-of-charge indicator strips of batteries. Now-a-days, an aim of research in electrochromic devices is to develop smart windows. It is applied in buildings to save energy cost by controlling the incident sun light and heat radiation. In this regard, Llordes *et al.* [68] reported a nanocomposite capable of tunable visible light as well as near-infrared transmittance. It is found that the development of smart windows with various switchable states including transparent, dimmed, cold and hot is possible with the use of this material. In this nanocomposite, the heat radiation transmittance can be controlled by ITO nanocrystals that exhibit an extensively tunable localized surface plasmon resonance [69]. It is also reported that the infrared transmittance is electrochemically controlled by the carrier concentration of ITO nanocrystals [69].
