Cu2ZnSnS4 alloys synthesized from Cu2SnS3@ZnS nanoparticles via a facile hydrothermal approach

•The Cu2SnS3@ZnS nanoparticles were prepared via a two-step hydrothermal route.•Cu2ZnSnS4 was achieved by annealing the Cu2SnS3@ZnS core–shell nanoparticles.•This approach is cost-effective and would be scaled up for industrial production.

A facile and low-cost approach was developed to prepare high quality quaternary Cu2ZnSnS4(CZTS) alloys through the thermal treating of the core–shell Cu2SnS3@ZnS nanoparticles. The synthesis process of the core–shell structure involves a simple two-step hydrothermal route that starts from the well-dispersed ternary Cu2SnS3 core with the introduction of poly(vinylpyrrolidone) (PVP) in the reaction solution, and ended by the coated binary ZnS shell upon the adsorption of citrate groups onto the preformed cores. X-ray diffraction, Raman spectrum and UV–vis absorption spectrum confirmed the single-phase formation and the proper bandgap of 1.51 eV for the CZTS alloys. This effective hydrothermal method can be readily applied for industrial production.

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