Synthesis Flower-Like ZnO Films and Their Photovoltaic Properties for Dye-Sensitized Solar Cells

Flower-like ZnO films were synthesized by chemical bath deposition, and their performance as photoanodes for dye-sensitized solar cells (DSSCs) was investigated. The physical and chemical properties of the grown layers as a function of Zn2+ concentration were investigated by scanning electron microscopy, energy-dispersive spectroscopy, and ultraviolet (UV)-visible spectroscopy. Electrochemical impedance spectroscopy and open-circuit voltage decay curve measurements were used to determine the kinetic processes of the ZnO photoanodes of the DSSCs. The results show that the bandgap of the ZnO film was smaller than that of the pure one. DSSCs with flower-like ZnO film with 0.05 M Zn2+ exhibited the smallest electron-transfer resistance in the ZnO/dye/electrolyte interface, indicating the highest light conversion efficiency. DSSCs based on 0.075 M Zn2+ showed the highest open-circuit voltage of 0.74 V.