Introduction of Pt-free counter electrode based on f-MWCNTs@NiMoSe2 nanocomposite for efficient dye-sensitized solar cells

Abstract

Herein, we have demonstrated the synthesis of carboxylic functionalized multi-walled carbon nanotubes (f-MWCNTs) encapsulated Ni-doped Molybdenum diselenide 2D nanosheets (f-MWCNTs@NiMoSe2) by cost-effective hydrothermal technique and served as a potential catalytic material in the dye-sensitized solar cells (DSSCs). The surface morphology and chemical information of the catalyst have been studied through the field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and X-ray diffraction (XRD) techniques. Taking the electrochemical characterizations including cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), Tafel, and power conversion efficiency (PCE) measurements exhibited that f-MWCNTs@NiMoSe2 delivered a better electrocatalytic behavior and outstanding chemical stability. The DSSCs fabricated with f-MWCNTs@NiMoSe2 revealed the most impressive catalytic activity with remarkable PCE of 7.39% versus Pt-based standard electrode (PCE: 6.10%). These results indicate that the substitution of Ni and presence of MWCNTs significantly enrich the active sites and electrical conductivity of MoSe2. Finally, the f-MWCNTs@NiMoSe2 gives a new opportunity for promising commercial application in DSSCs.