Multi-functional electrochromic energy storage smart window powered by CZTSSe solar cell for intelligent managing solar radiation of building

Electrochromic smart windows provide an important route to reduce building energy consumption by dynamically adjusting the transmission of visible and near-infrared light. However, the requirement for an external electrical supply greatly limits their application in energy-saving buildings. Herein, we develop a novel photovoltaic (PV) cell-powered electrochromic energy storage smart window prototype by the combination of nickel-cobalt bimetal oxide electrochromic window and Cu2ZnSn(S,Se)4 (CZTSSe) solar cell, which not only realizes the function integration of self-power and intelligent solar radiation regulation, but also extends its function to energy storage. Specifically, the obtained NiCoO2 electrochromic films display a large optical modulation (60.0% at 550 nm), fast switching time (7.6/11.4 s), outstanding stability and excellent rate capability. Based on the achieved NiCoO2 film and TiO2 film, high-performance electrochromic energy storage smart windows (EESW) were further assembled and demonstrated excellent compatibility with CZTSSe solar cell. Benefiting from the unique merits of CZTSSe cell, the self-powered EESW exhibits excellent optical modulation (56.0% at 550 nm) and fast coloration speed (17 s). Moreover, the self-powered EESW can serve as a power source to drive external electronics. Our exploration of multi-functional smart windows offers an effective strategy to realize a highly efficient low-energy building in the future.