Novel single pot synthesis of metal (Pb, Cu, Co) sulfide nanomaterials -Towards a quest for paintable electrode materials that supersedes Pt electrode

•Novel single pot selective stoichiometric synthesis of metal sulfide nanomaterials.•Employed a simple paint approach for the fabrication electrode materials.•Less charge transfer resistance of metal sulfide counter electrodes than Pt.•Correlation of stoichiometry of metal sulfide with activity as counter electrode.

Novel single pot selective stoichiometric synthesis of cobalt, copper and lead sulfide nanomaterials has been carried out in an energy and time efficient manner by using combustion synthesis for the first time without using surfactants, capping agents and inert atmospheric conditions. X-ray diffraction and transmission electron microscope revealed the formation of respective nanocrystalline metal sulfides with different stoichiometry, whereas, electrochemical impedance analyses confirmed the low charge transfer resistance of all metal sulfide counter electrodes when compared to the Pt counter electrode, indicating their potential to be used as electrode materials. The efficiency of metal sulfide counter electrodes was tested in quantum dot sensitized solar cells (QDSSC) by applying the metal sulfide paint on fluorine doped tin oxide (FTO) plates. Current-voltage characteristics ratified the solar conversion efficiencies of 0.85, 1.3, 0.91 and 0.25, respectively for PbS (2), CuS (3), CoS (2) and Pt counter electrodes with CdS/TiO2 (1:1) working electrode and Na2S electrolyte. Thus the present study furnishes a novel method for the synthesis of metal sulfides as efficient paintable counter electrodes that can overcome Pt as counter electrode in QDSSC.

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