Electrochromism

Redox couple for a viologen. The 2+ species on the left is colorless, and the 1+ species on the right is deep blue or red, depending on the identity of R.[1]

Electrochromism is a phenomenon in which a material displays changes in color or opacity in response to an electrical stimulus.[2] In this way, a smart window made of an electrochromic material can block specific wavelengths of ultraviolet, visible or (near) infrared light. The ability to control the transmittance of near-infrared light can increase the energy efficiency of a building, reducing the amount of energy needed to cool during summer and heat during winter.[1][3]

As the color change is persistent and energy needs only to be applied to effect a change, electrochromic materials are used to control the amount of light and heat allowed to pass through a surface, most commonly "smart windows". One popular application is in the automobile industry where it is used to automatically tint rear-view mirrors in various lighting conditions.

  1. ^ a b Mortimer, R.J. (2011). "Electrochromic Materials". Annu. Rev. Mater. Res. Vol. 41. pp. 241–268. Bibcode:2011AnRMS..41..241M. doi:10.1146/annurev-matsci-062910-100344. PMID 12449538.
  2. ^ Chua, Ming Hui; Tang, Tao; Ong, Kok Haw; Neo, Wei Teng; Xu, Jian Wei (2019). "Chapter 1 Introduction to Electrochromism". Electrochromic Smart Materials: Fabrication and Applications. Smart Materials Series. Royal Society of Chemistry. pp. 1–21. doi:10.1039/9781788016667-00001. ISBN 978-1-78801-143-3. S2CID 139718051. Retrieved 29 July 2022.
  3. ^ Miller, Brittney J. (8 June 2022). "How smart windows save energy". Knowable Magazine. doi:10.1146/knowable-060822-3. Retrieved 15 July 2022.