ZnO Hierarchical Nanostructures for Advanced Dye-Sensitized Solar Cell Applications

Various ZnO hierarchical nanostructures such as nanosheets and nanocactuses are prepared by a two-step electrodeposition process. Dye sensitized solar cells (DSSCs) based on these nanostructures are fabricated under similar conditions for comparison. The nanocactuses based DSSCs show better performance, resulting from the increased dye loading and enhanced light absorption due to the large surface area and light trapping effects of the unique structures. The charge recombination and lifetime measurement by electrochemical impedance spectroscopy indicates that the hierarchical structures help suppress the recombination and increase the lifetime of photoelectrons due to the improved interconnection among the nanostructures. The hierarchical nanostructures show promising potential for applications in cost-effective DSSCs.