(Funded by the U.S. Department of Energy)
Researchers at the U.S. Department of Energy’s Lawrence Livermore National Laboratory have developed a new type of electrically controlled, near-infrared smart window that can cut near-infrared light transmission by almost 50%. In these smart windows, carbon nanotubes are grown so they stand upright on the glass, like a microscopic forest. Depending on the voltage applied, the nanotubes can either absorb infrared light and block heat from the sun or let the infrared light through. Once the carbon nanotubes are put into either a blocking or transparent state, they retain charge well, and so, a continuous voltage is not needed to maintain that state. This property offers very low-power operation, a necessity to drive energy savings for the end user.
https://www.llnl.gov/article/53296/carbon-nanotube-smart-windows-offer-energy-savings