Free-standing graphene/NiMoS paper as cathode for quasi-solid state dye-sensitized solar cells.

Highly catalytic two dimensional and metal-doped two-dimensional nanomaterials (MoS2 and NiMoS) were deposited over free-standing graphene (FSG) paper using electrodeposition method and subsequently used as a counter electrode in quasi solid-state dye-sensitized solar cells (q-DSSCs). The replacement of FTO by FSG facilitates high electrical conductivity and electrodeposited metal sulphides provide electrocatalytic activity. The morphology, structural phase formation and chemical composition of FSG-MoS2 and FSG-NiMoS were investigated using FESEM, XRD, Raman and XPS analysis. The electrochemical behavior of metal sulphide decorated FSG cathodes is investigated using an electrochemical workstation and their effects on the photo-conversion efficiency of DSSCs were assessed. NiMoS with FSG substrate is an intriguing counter electrode material that can be utilized at low fabrication cost than the conventional platinum-based counter electrodes. FSG along with the metallic-two dimensional nanoparticles (NiMoS) functions as an effective catalytic material thereby allowing DSSCs to achieve enhanced efficiency of ∼7% to provide better alternative of FTO and Pt.