Stacked vanadium pentoxide–zinc oxide interface for optically-chargeable supercapacitors

Abstract

Optically-chargeable supercapacitors effectively convert photon energy into electrochemical energy and store them for further utilization. In this work, we developed a metal oxide-based optically responsive symmetrical supercapacitor using a novel stacked vanadium pentoxide/zinc oxide (V₂O₅/ZnO) semiconducting heterostructure on fluorine-doped tin oxide (FTO) glass. The selected metal oxides' distinct bandgaps and work functions form a unique heterostructure that facilitates the separation and flow of photogenerated charge carriers. The stacking induces a maximum increment of ∼178% in specific capacitance under ultraviolet (UV) light illumination measured from the device's galvanostatic charge–discharge (GCD). The effect of UV light on the device was also verified by analyzing the open circuit potential, where the device showed excellent electrochemical performance and stability for more than 5000 cycles. These findings pave a progressive way toward developing self-chargeable energy storage devices and promise breakthrough advancements.