Characterization of two-way fabricated hybrid metal-oxide nanostructured electrode materials for photovoltaic and miniaturized supercapacitor applications

Abstract Portable electronic devices require a small volume self-powered energy system that can combine fabrication of energy harvesting and storage devices in one plane. This study focuses on fabricating novel all-oxide photovoltaic and supercapacitor devices based on MoO3, V2O5, and CoxOy thin electrodes prepared by a two-electrode cell arrangement. The fabricated devices were tested using solar simulator and potentiostat at ambient temperature. The power conversion efficiencies of the fabricated photovoltaic devices were found in the range of 0.17–0.39% depending on buffer layer characteristics. It therefore suggests that V2O5 and MoO3 can buffer photovoltaic processes by lowering the conduction band offset in the proximate CoxOy absorber. Pseudocapacitive behavior of MoO3/CoxOy||MoO3/CoxOy and V2O5/CoxOy||V2O5/CoxOy planar devices showed that they delivered maximum specific areal capacity values of 0.694 and 0.778 μAhcm−2 respectively at discharge current density of 0.1 mAcm−2. They also showed considerably low reduction in energy density (about 38.7%) even at a remarkable increase in power density of about 450% (at a high current density of 1.0 mAcm−2). In addition, the symmetric microsupercapacitors showed excellent retention of capacity even after 5000 cycles. These results generally indicate the reliability of the fabricated devices in the development of portable electronic components for energy application.