MoS2 nanosheets based counter electrodes: An alternative for Pt-free dye-sensitized solar cells

Abstract

Dye-sensitized solar cells are assembled with MoS2 nanosheets based counter electrodes synthesized via hydrothermal route using ammonium molybdate tetrahydrate and thiourea as precursor materials. Basic and specific studies are followed to characterize MoS2 as counter electrode material by XRD, SEM, TEM, EDX, cyclic voltammetry and electrochemical impedance spectroscopic studies. Dye-sensitized solar cells device is fabricated by using fluorine-doped tin oxide glass plate coated with TiO2 as photoanode, Cis-bis(isothiocyanato)bis(2,2′-bipyridyl-4,4′-dicarboxylato)ruthenium(II) dye as a light harvester, and iodine/iodide as a liquid electrolyte. The fabricated dye-sensitized solar cells device with MoS2 counter electrode showed an open circuit voltage of 795 mV, short circuit current of 19.6 mA/cm2, fill factor of 0.36, and power conversion efficiency of 6.6% upon comparing to Pt counter electrode which showed an open circuit voltage of 827 mV, short circuit current of 14.8 mA/cm2, fill factor of 0.47, and power conversion efficiency of 6.8%. In addition to this, MoS2 coupled reduced graphene oxide counter electrodes are prepared by simply dispersing reduced graphene oxide and MoS2 in isopropyl alcohol which showed the best performance with open circuit voltage of 800 mV, short circuit current of 20.5 mA/cm2, fill factor of 0.42, and power conversion efficiency of 8.1%.