Solvothermal growth of 3D flower-like CoS@FTO as high-performance counter electrode for dye-sensitized solar cell

Abstract

In this work, a simple and one-step solvothermal method has been developed for directly growing three-dimensional flower-like cobalt sulfide (CoS) on the fluorine-doped tin oxide coated glass substrate (FTO) for the counter electrode in the dye sensitized solar cell. The electroctalytic activity of the CoS@FTO towards the I-3(-) to I- reduction exhibited almost similar electrocatalytic properties to the Pt-based counter electrode. The dye-sensitized solar cell (DSSC) assembled with CoS@FTO counter electrode attained almost similar photovoltaic performance (5.64%) to that of the DSSC with Pt@FTO counter electrode (5.9%) under 1 sun illumination. The adhesion stability of the CoS deposited at FTO was also studied using strong adhesive tape test, and the results show that after the strong adhesive tape test, the CoS@FTO retained almost 95% of the coating. The similar and comparative performance of the CoS@FTO to the Pt@FTO may be due to the high surface area originating from the 3D flower-like morphology, and the excellent electrocatalytic activity of the CoS.