Facile template-free preparation of silver-coated Cu3SbS4 hollow spheres with enhanced photoelectric properties

Abstract

Hollow polycrystalline structures and noble-metal-coating endow ternary sulfides with promising light absorption and electrical properties for solar energy conversion applications. We developed a facile one-pot solvothermal chemical route to synthesize hollow Cu₃SbS₄ microspheres with an opening. Additionally, four phase-pure Cu–Sb–S high-quality nanocrystals can be produced in a selectable way by the same route. The detailed evolution process and self-driven breakage mechanism have been proposed in detail. Subsequently, in situ reduction of the Ag-ion precursor was conducted and Ag clusters were uniformly deposited in the hollow spherical architecture with a nanoparticle-textured surface and interior to mitigate the oxidization of Cu₃SbS₄ nanoparticles. The created hollow metal-semiconductor nanocomposite opens up a favorable new situation. The nanocomposites exhibited a remarkably enhanced absorption of over 2 × 10⁵ cm⁻¹, covering the UV and visible regions of the electromagnetic spectrum. The electrical resistivity decreased drastically by 90% after the coating of noble metals. A reduction in the bandgap energy after the addition of Ag to Cu₃SbS₄ was confirmed from extrapolated optical results and theoretical calculation validation. The synthetic effect of hollow structures and nanocomposites results in the superior performance of Cu–Sb–S compounds, thus highlighting their potential applications in light absorbers and energy conversion technologies.