Properties of electrochromic windows enhanced with water

According to the team, the advance would allow building occupants to switch their windows between three modes: transparent, or “normal” windows; windows that block infrared light, helping to keep a building cool; and tinted windows that control glare while maintaining the view. Their work, carried out in collaboration with colleagues from University of Texas at Austin and Vanderbilt University, is detailed in ACS Photonics.

“Our work demonstrates that there are more options available,” Veronica Augustyn, co-corresponding author of a paper on the work said in a statement. “Specifically, we’ve shown that you can allow light to pass through the windows while still helping to keep buildings cooler and thus more energy efficient.”

Key to more dynamic window materials is water. When water is bound within the crystalline structure of a tungsten oxide – forming tungsten oxide hydrate – the material is said to exhibit a previously unknown behaviour.

Tungsten oxides have been used in dynamic windows due to them being transparent. By applying an electrical signal, and injecting lithium ions and electrons into the material, the material becomes dark and blocks light.