Synthesis of Fe3O4/ZnO from Zinc Dross Waste as an Active Material for Dye-Sensitized Solar Cells

Abstract

Zinc oxide (ZnO) is an attractive active material in emerging solar cell technologies, such as dye-sensitized solar cells (DSSCs), due to its high stability and electron mobility. The activity of ZnO can be enhanced by adding a small amount of impurity, such as iron oxide. Since zinc dross contains Zn as the primary element and Fe as the minor element, it can be used as a precursor to obtain iron oxide/ZnO. In this study, ZnO was prepared from zinc dross through a hydrometallurgy process and utilized as the active material for DSSCs. For comparison, pure ZnO was also prepared using zinc acetate as the precursor through the sol-gel process. X-ray diffraction (XRD) results show that pure ZnO was observed in the sample prepared using zinc acetate as the precursor, while ZnO with a Fe₃O₄ phase was observed in the sample prepared using zinc dross. Scanning electron microscopy (SEM) examinations reveal that the thickness of ZnO layer that was deposited onto fluorine-doped tin oxide glass was 11.3 ± 0.4 μm. The solar cell performance tests showed that the presence of dyes that adsorbed on ZnO synthesized from zinc dross could increase the efficiency of DSSCs up to 26.5 times while the ZnO synthesized from zinc acetate has 11.5 higher efficiency compared to the non-sensitized counterpart. Moreover, ZnO from zinc dross exhibited 1.2 times higher efficiency than ZnO from pure Zn precursor, indicating the feasibility of converting zinc dross waste into valuable materials.