Investigating the Effects of Thickness on the Performance of ZnO-Based DSSC

Zinc oxide nanostructures exhibit unique properties which make them suitable for dye-sensitized solar cell applications. Their specific properties such as appropriate optical properties, proper energy band gap and high electron transfer characteristics have motivated researchers to use them in the fabrication of dye-sensitized solar cell photo-anodes. In the present study, the effect of thickness on the performance of a new ZnO photo-anode has been studied. All the photovoltaic parameters of the cells fabricated using N719 ruthenium dye were measured. SEM technique was utilized to determine the thickness and the UV-Visible method was used to study the transparent properties of the photo-anodes. Electrochemical impedance spectroscopy technique was employed to determine the appropriate equivalent circuit for studying the electron transfer mechanisms in all the fabricated cells. The results demonstrated that the ZnO thickness is a critical parameter for providing either sufficient resistance to suppress the charge recombination process or appropriate electron transferring properties. The optimized ZnO photo-anode was obtained at a thickness of 19 µm, which resulted in an efficiency of 3.22%.