Semitransparent organic photovoltaics with wide geographical adaptability as sustainable smart windows

Semitransparent organic photovoltaics (ST-OPVs) have gained significant attention due to their rapid iteration of high-efficiency photoactive materials and potential applications in building-integrated photovoltaics as smart windows. In this work, we establish a parameter (FoM_LUE) to evaluate the potential of photoactive materials for ST-OPVs, combining average visual transmittance, bandgap, and current density. PBOF and eC9 exhibit the highest FoM_LUE values of 0.084 and 0.161 for the investigated donors and acceptors, respectively. We achieve a light utilization efficiency of 6.05% as the figure of merit for all semitransparent solar cells. The derived ST-OPV exhibits enhanced thermal insulation and operational stability compared to its counterpart. The geographical analysis indicates that the hot summer/warm winter zone is the most suitable for ST-OPV glazing windows, delivering an annual total energy-saving of 1.43 GJ m^-2. Our results demonstrate the multifunctionality and geographical factors of ST-OPVs for constructing sustainable energy-saving smart windows.