Transparent metal-oxide photovoltaics for energy harvesting and storage for sustainable platforms

A transparent photovoltaic (TPV) energy harvesting method would provide more degrees of freedom for deployment on windows, buildings, vehicles, and surfaces with less soil dependency. This study designs a TPVintegrated energy storage system (capacitor charger) as a sustainable energy platform. The TPV device comprises a metal-oxide junction with a thin Si layer to enhance light utilization across a broad spectrum. Wide-bandgap metal-oxide-based materials absorb high-energy ultraviolet (UV) photons, while the Si layer captures longer wavelength lights due to the lower bandgap. The TPV structure (FTO/NiO/p+-Si/a-Si/n+-Si/AZO/ITO) exhibits an average visible transparency of 37 % and a power conversion efficiency of 4.97 % under 405 nm UV light illumination. The excellent electrical characteristics with a short-circuit current density of 10.1 mA/cm2 and open-circuit voltage value of 0.79 V allow TPVs to serve as a power source for rapidly charging capacitor banks in the energy storage unit. This PV-linked capacitor energy system can illuminate LED lamps, suggesting an on-site sustainable energy platform. The proposed Si-embedded TPV demonstrates electric power generation across broad wavelengths, enabling the bi-directional PV utilization of sunlight and indoor light sources for energy harvesting both day and night.