Novel ZnCo2O4/WO3 nanocomposite as the counter electrode for dye-sensitized solar cells (DSSCs): study of electrocatalytic activity and charge transfer properties

Nowadays, Pt coated FTO is used conventionally as the counter electrode in dye-sensitized solar cell (DSSC). In addition to the high price of the Pt electrode, it reduces the stability of the DSSC. In this study, we introduce and study a new counter electrode based on the ZnCo2O4/WO3 composite that is used in DSSC. We show that the efficiency of the DSSC can be enhanced even more then the Pt-based one by employing the ZnCo2O4/WO3 as counter electrode. By examining the structural, morphological, optical, and electrochemical properties of the synthesized electrodes, we investigate the counter electrodes synthesized under different conditions. The XRD patterns and FESEM images confirm that the composite phase of the ZnCo2O4/WO3 layers is formed. Additionally, electrochemical studies by CV, Tafel, EIS, and Mott-Schottky methods indicate the electrocatalytic activity of the ZnCo2O4/WO3 sample have significantly increased compared to ZnCo2O4 and WO3 electrodes. Furthermore, the characterization of DSSCs with TiO2 photoanode and different counter electrodes show that the efficiency of the solar cells based on ZnCo2O4/WO3 has a promising efficiency of 7.76%, which has increased by 7% compared to the Pt one.