Enhanced Performance of Dye-Sensitized Solar Cells Using Natural Dye Mixtures and Mesoporous TiO₂ Photoelectrodes

Abstract

In this study, dye-sensitized solar cells (DSSCs) were fabricated using natural dyes extracted from blackberry, spinach, and red cabbage as environmentally friendly photosensitizers. The optical properties of the extracted dyes were examined using UV–visible spectroscopy. The photovoltaic performance of the DSSCs was evaluated using two two types of photoelectrodes: commercial TiO₂ and laboratory-prepared mesoporous TiO₂. The photoelectrodes were deposited onto fluorine-doped tin oxide (FTO) substrates via electrophoretic deposition, while platinum counter electrodes were prepared by spin coating. The assembled DSSCs were characterized under simulated solar illumination using a liquid iodine-based electrolyte. Among the investigated sensitizers, the mixed natural dye composed of blackberry, spinach, and red cabbage achieved the highest power conversion efficiency of 1.4%, with an open-circuit voltage of 0.76 V, a short-circuit current density of 2.93 mA·cm⁻², and a fill factor of 62.98%. In comparison, the DSSC sensitized with blackberry dye alone reached an efficiency of 0.72%. These results demonstrate the potential of natural dye mixtures combined with nanostructured photoelectrodes for improving the photovoltaic performance of DSSCs. The present work highlights the feasibility of using low-cost, eco-friendly materials in the development of sustainable solar energy devices. However, a slight decrease in performance was observed after two days, highlighting the need for further optimization to improve the long-term stability of the DSSCs.