Binary transition metal sulfides as an economical Pt-free counter electrodes for dye-sensitized solar cells

Abstract Binary CuxCoySz sulfide based Pt-free counter electrodes (CE) were prepared in one-step solvothermal synthesis process. The obtained CEs were characterized by SEM, XRD, and Raman spectroscopy methods. EDX analysis showed uniform distribution of Cu, Co and S. SEM images revealed different level of coverage of the FTO glass by the binary metal sulfide products. DSSCs were constructed using proposed CEs with N719 dye, and their photovoltaic and electrochemical performances were assessed against Pt reference cell. The efficiency of the CuxCoySz-3 CE produced an 11% improvement of its photovoltaic efficiency compared to the reference cell.