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.