Chemistry researchers from the University of British Columbia (UBC) have come up with a cost-effective technique for making smart windows that self-tint in response to an electrical current.
These electrochromic windows can help reduce energy consumption in buildings, says a paper published by the researchers in the international journal Chem. By changing color, the window glass dynamically controls solar irradiation to buildings, minimising the need for artificial lighting or heating.
Lead author Wei Cheng says the team came up with the method by building on an existing technique that was co-developed at UBC. According to a press statement, the technique involves depositing “a liquid solution containing a metal ion onto glass and then using ultraviolet light to transform it into a film that coats the glass. The film is completely transparent but becomes blue when electricity passes through, ultimately creating the active component of a smart window.” Currently, the researchers are experimenting with more neutral tints, like grey, for the windows.
The metal oxide films display state-of-the-art electrochromic performance parameters, such as an optical modulation of 70 percent at 700 nm, colored and bleached on the order of seconds.
Curtis Berlinguette, a professor of chemical and biological engineering at UBC’s Stewart Blusson Quantum Matter Institute, has been quoted in the statement as saying, “Conventional windows waste a third of all energy used to heat, ventilate and air condition buildings. Smart window technologies offer the opportunity to reduce these energy losses but the main challenge is finding ways to make these windows less expensive.”
Companies making electrochromic glass currently make films using physical deposition methods and sophisticated vacuum equipment.
“Our technique creates a uniform dynamic coating without the need for special instrumentation,” says Cheng. “Another advantage of our method is that it is compatible with many different metals and it is scalable. We are excited to potentially fine-tune the dynamic properties of the materials to improve performance even further and make large windows for commercial use.”