Thermochromic hydrogel-based energy efficient smart windows: fabrication, mechanisms, and advancements.

Thermochromic smart windows are regarded as highly cost-effective and easily implementable strategies with zero energy input among the smart window technologies. They possess the capability to spontaneously adjust between transparent and opaque states according to the ambient temperatures, which is essential for energy-efficient buildings. Recently, thermochromic smart windows based on hydrogels with various chromic mechanisms have emerged to meet the increasing demand for energy-saving smart windows.