Truly Transparent Solar for Electricity Generating Facades

Building-integrated photovoltaic (BIPV) technologies are a promising pathway to capturing large areas of solar energy and increasing building efficiency at the point of utilization. However, the widespread adoption of such technologies is severely hampered by the cost and aesthetics associated with mounting traditional PV cells on façade materials such as windows. We examine this problem with the development a transformative visibly transparent photovoltaic window coating, which allows for seamless integration of combined energy harvesting and solar control into the building environment. The truly transparent solar coating selectively converts incident ultraviolet and infrared light into electricity and simultaneously blocks transmission of unwanted solar heat, all while selectively transmitting visible light. Here we examine the practical performance targets for such coatings and demonstrate simultaneous optimization of (1) power conversion efficiency, (2) visible light transmission, (3) solar heat gain coefficient, (4) emissivity, and (5) color. We conclude by demonstrating integration into insulated glass units (IGUs) and fabrication into prototype façades (>1 m^2).