Energy storage capability of the dye sensitized solar cells via utilization of highly porous carbon electrodes

Abstract

Dye sensitized solar cells (DSSCs) have shown promising results in the field of renewable energy owing to their low cost and portable features. In practical applications, their harvested energy could be stored in a supercapacitor once it exceeds the regular consumption. Various methods of manipulation of the active electrode have been examined to facilitate the energy storage of the system, whereas the counter electrode has always been known for its catalytic functionality and its contribution to the capacitive response of the device left a well-oriented study to be desired. In this work, the substitution of the platinum electrode with a specific porous electrode resulted in a supercapacitive behavior of the device. The photoactive electrode was fabricated using zinc oxide nanowires (ZnO) grown on a conductive transparent substrate with hydrothermal deposition method. The electrode was used to make a standard DSSC using a ruthenium dye, iodide/triiodide standard redox electrolyte, and a platinum counter electrode. The cyclic voltammetry (CV) study of the device showed a low capacitance with 350 mV open circuit voltage. Replacing the platinum counter electrode with a particularly designed porous paper-based carbon nanotube electrode resulted in a considerable difference in the CV response. A capacitive behavior was observed due to the large surface area of the counter electrode and the ZnO nanostructures on the photoactive electrode. Due to the large capacitance and relatively small photocurrent, the change in the open circuit voltage was limited. However, enhancement of the photocurrent could improve both the energy harvesting and charge storage in the device.