Building-integrated photovoltaic smart window with energy generation and conservation

Energy usage in buildings accounts for 40% of global energy consumption, while windows are the least energyefficient part of buildings. Photovoltaic smart window is an efficient way to improve efficiency of the window. In this work, we proposed a building-integrated photovoltaic (BIPV) smart window with energy modulation, energy generation, and low emissivity function by combing perovskite solar cell and hydrogel. The fabricated BIPV smart window achieved average visible transmittance (AVT) of 27.3% at 20 ◦C and 10.4% at above 40 ◦C with energy modulation (Tsol) of 15.7%. The high peak conversion efficiency (PCE) of 17.5% and low emissivity of 0.31 further improve the energy efficiency of the smart window. Compared with a current smart window that only modulates solar energy, our BIPV smart window which integrated energy modulation, energy generation, and low-E function achieves better energy saving.