Analysis of multilayer based TiO2 and ZnO photoanodes for dye-sensitized solar cells

In dye sensitized solar cells (DSSCs), ZnO reduces the rate of reTiO2 bination of electron-hole pair from TiO2 nanoparticles to electrolyte. Therefore, in this research, we report a comparative study of multi layers of TiO2/ZnO/TiO2 (TZT) and ZnO/TiO2/ZnO (ZTZ) thin films based DSSCs fabricated by sol-gel technique. The counter electrodes were graphene coated FTO glasses. N719 ruthenium dye was used in these cells and photovoltaic parameters e.g., 'short circuit current density (Jsc), fill factor (FF), open circuit voltage (Voc), and conversion efficiency (η)' were calculated. XRD showed that films have only ZnO and TiO2 particles. SEM micrographs revealed that TZT film has large internal surface are for dye loading then ZTZ film. UV–vis absorbance graph confirmed that ZTZ film absorbed low dye than ZTZ film. It is found that the TZT layered cell has high Jsc and Voc in comparison with ZTZ cell, resulting high efficiency. The present work will introduce a new structure for the fabrication of highly efficient DSSCs using multilayer thin films as photoanode.