Cobalt telluride/reduced graphene oxide using as high performance counter electrode for dye-sensitized solar cells

A cobalt telluride/reduced graphene oxide (CoTe/RGO) hybrid is synthesized by hydrothermal method and used as counter electrode in dye-sensitized solar cell (DSSC). The synthesized samples are characterized by field emission scanning electron microscopy and transmission electron microscope, which shows that CoTe/RGO has a larger specific surface area than CoTe. Cyclic voltammogram measurement indicates that CoTe/RGO electrode has larger current density and better electrocatalytic activity in the reduction of triiodidie than Pt electrode. Electrochemical impedance spectroscopy shows that CoTe/RGO electrode has lower charge-transfer resistance (2.94 Ω cm2). Owing to above advantages, the DSSC based on CoTe/RGO counter electrode achieves a high power conversion efficiency of 9.17%, outperforming that based on Pt counter electrode (8.17%). Therefore, inexpensive CoTe/RGO is a promising counter electrode to replace noble metal Pt.