The Sb ₂(S _{1- x}, Se _x) ₃ compound has received considerable attention in photovoltaic applications due to its physical properties and for containing abundant non-toxic elements. However, solar cells based on this material present low efficiencies. In this work, we review some of the physical properties reported for the semiconductors Sb ₂S ₃, Sb ₂Se ₃ and Sb ₂(S _{1- x}, Se _x) ₃, and the main techniques of film deposition of the Sb ₂(S _{1- x}, Se _x) ₃ ternary material along with the reported efficiencies. Finally, a brief review of the scarce theoretical analyses of the main properties of this semiconductor (refractive index, band-gap energy, absorption coefficient and recombination) is presented. This review remarks the need of more theoretical analyses and modeling to optimize and improve the fabrication processes of Sb ₂(S _{1- x}, Se _x) ₃ solar cells in order to reach better conversion efficiencies.

Kesterite semiconductors such as Cu ₂ZnSnS ₄, Cu ₂ZnSnSe ₄ and Cu ₂ZnSn(SSe) ₄ have received a great deal of attention from scientific community for solar cell applications since they present p-type conductivity, direct band-gap transitions, a relatively high absorption coefficient and a band-gap that can be tailored in the range of 1.0—1.5 eV as a function of Se/S compositional ratio. Besides, these materials are based on abundant and low toxicity elements. In spite of the great effort carried out by the scientific community to promote device performance, Kesterite solar cell efficiency is still limited to values lower than 13%. In this sense, new strategies are required to overcome currently reported values. In this paper, a minireview on the state of the art concerning Kesterite solar cell technology is presented. Different current trends to promote Kesterite solar cell efficiency are presented and discussed.