Synthesis of CuSbS2 Nanoplates and CuSbS2-Cu3SbS4 Nanocomposite: Effect of Sulfur Source on Different Phase Formation.

Layered CuSbS2 and related ternary metal chalcogenides have attracted huge research interest due to their potential applications in sustainable energy storage, photovoltaics, and related area. Here, we report facile synthesis of CuSbS2 nanoplates and CuSbS2-Cu3SbS4 nanocomposite using hot injection method with varying sulfur precursors. Elemental sulfur (S8) as sulfur precursor results in nanoplates of pure CuSbS2, while thioacetamide (TA) as sulfur source gives nanocomposite with Cu3SbS4 nanoparticle decorated on the surface of CuSbS2 nanoplates. The ease of reduction of TA as compared to sulfur at high temperature, in the presence of oleylamine, promotes the oxidation of antimony from (III) to (V) state and the formation of Cu3SbS4 phase containing Sb(V). Raman scattering study confirms the presence of Cu3SbS4 phase in CuSbS2-Cu3SbS4 nanocomposite. X-ray photoemission spectroscopy study on CuSbS2 nanoplates and CuSbS2-Cu3SbS4 nanocomposite confirms the desired valence state of the constituent elements. Electrochemical properties measurement shows better specific capacitance for CuSbS2-Cu3SbS4 nanocomposite (151 F/g) as compared to CuSbS2 nanoplates along with long-term cyclic stability with 68.2% capacitance retention.