Nanocrystals of indium tin oxide (blue) embedded in a glassy matrix of niobium oxide (green) form a composite material that can switch between NIR-transmitting and NIR-blocking states with a small jolt of electricity. Credit: Berkeley Lab
BERKELY, Calif., Aug. 14 (UPI) -- U.S. researchers say a new material can make smart windows even smarter, allowing them to control both visible and heat-producing near-infrared light.
Windows with a thin coating of nanocrystals embedded in glass can dynamically modify sunlight as it passes through a window to maximize both energy savings and occupant comfort in a wide range of climates, scientists at the U.S. Department of Energy's Lawrence Berkeley National Laboratory reported Wednesday.
"In the United States, we spend about a quarter of our total energy on lighting, heating and cooling our buildings," research leader Delia Milliron said. "When used as a window coating, our new material can have a major impact on building energy efficiency."
Controlling near-infrared light means building occupants can have natural lighting indoors without unwanted thermal gain, reducing the need for both air-conditioning and artificial lighting, the researchers said.
The heart of the new technology is a new "designer" electrochromic material made from nanocrystals of indium tin oxide embedded in a glassy matrix of niobium oxide, that can control visible and near-infrared light in reaction to an electrical charge applied to the windows.
With the new coating a window can be switched to a full dark mode, blocking both light and heat, or to a bright, fully transparent mode, the researchers said.
"We're very excited about the combination of unique optical function with the low-cost and environmentally friendly processing technique," study co-author Anna Llordes said. "That's what turns this 'universal smart window' concept into a promising competitive technology."
