
thumb|180px|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.]]
thumb|180px|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.]]
Electrochromism is a phenomenon in which a material displays changes in color or opacity in response to an electrical stimulus. 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.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).