Researchers reported a new low-temperature process for coating the smart material on plastic, which makes it easier and cheaper to apply than conventional coatings made directly on the glass itself.
The low-temperature process developed by Delia Milliron from The University of Texas at Austin and her colleagues generates a material with a unique nanostructure, which doubles the efficiency of the coloration process compared with a coating produced by a conventional high-temperature process.
It can switch between clear and tinted more quickly, using less power, researchers reported in a study published online in the journal Nature Materials.
The team demonstrated a flexible electrochromic device, which means a small electric charge (about four volts) can lighten or darken the material and control the transmission of heat-producing, near-infrared radiation.
Such smart windows are aimed at saving on cooling and heating bills for homes and businesses.
The new electrochromic material, like its high-temperature processed counterpart, has an amorphous structure, meaning the atoms lack any long-range organisation as would be found in a crystal.
However, the new process yields a unique local arrangement of the atoms in a linear, chain-like structure.
Whereas conventional amorphous materials produced at high temperature have a denser three-dimensionally bonded structure, the researchers' new linearly structured material, made of chemically condensed niobium oxide, allows ions to flow in and out more freely.
As a result, it is twice as energy efficient as the conventionally processed smart window material, the study said.
