Spin-coated uniform Sb₂S₃ thin films for photovoltaic applications by solvent engineering

Spin-coated Sb₂S₃ inorganic semiconductor thin films are a good substitute for conventional Sb₂S₃ absorbers prepared by chemical bath deposition due to the ability to control antimony oxide defects and the simplicity of the spin-coating process. However, precise control of the morphology of the Sb₂S₃ thin films is crucial for optimizing the photovoltaic properties of inorganic-organic hybrid solar cells. In this work, we attempt to fabricate high-purity Sb₂S₃ thin films with a uniform morphology via solvent engineering. The compositional ratio and concentration of the precursor solutions containing SbCl₃ and thiourea are varied, and the chemical composition and morphology of the spin-coated Sb₂S₃ thin films are investigated. The morphology of the Sb2S3 thin films is predominantly determined by the morphology of the precursor films, which are formed by a complex reaction between SbCl₃ and thiourea after the spin-coating process. Controlling the complex reaction enables the fabrication of uniform Sb₂S₃ thin films using the spin-coating process. In order to evaluate the photovoltaic properties of the spin-coated Sb₂S₃ thin films, planar Sb₂S₃ solar cells comprised of Au/Poly-3-hexylthiophene/Sb₂S₃/bl-TiO₂/FTO are fabricated, and the current-voltage characteristics of these solar cells are investigated.