Active energy-controlling windows incorporating transparent photovoltaics and an integrated transparent heater

Summary Despite being essential interfaces between interior spaces and their surrounding environments, windows are often considered as being among the least important energy components in buildings, houses, and vehicles. The proportionally large window areas of man-made structures mean that smarter window design would lead to more efficient energy control. Here we report large-scale transparent photovoltaics and their integration with a transparent heater for an energy-efficient active window unit. The latter possesses high average visible transmittance (>60%), low transmission haze (