Sb₂Se₃ thin films prepared by chalcogenization of their metallic precursor have been used as the active layer in solar cells. The samples were prepared using a reactor that enables the growth of Sb₂Se₃ films through selenization of an Sb layer previously deposited on Mo-coated glass substrates via evaporation. The selenization process was conducted in a controlled atmosphere of an argon-hydrogen mixture, followed by thermal annealing in the presence of elemental selenium in a tubular furnace heated by infrared lamps. The entire process was automatically controlled using algorithms developed in the LabVIEW programming environment. Through a study of deposition conditions—including the effects of variables such as furnace heating rate, final annealing target temperature, annealing time, and partial pressure of the H₂+Ar mixture—conditions were identified for growing single-phase Sb₂Se₃ films with good structural, optical, and morphological properties. This indicates that the Sb₂Se₃ films prepared using the chalcogenization process developed in this work can be used as an absorber layer in solar cells. An efficiency of 4.2% was achieved with devices fabricated using the Mo/Sb₂Se₃/CdS/i-ZnO/n+ZnO/Ag architecture; this efficiency was improved to 5.3% by incorporating a TiO₂ layer between the Sb₂Se₃ absorber and the CdS buffer to prevent degradation of the Sb₂Se₃ absorber during the deposition of the CdS layer by the Chemical Bath Deposition (CBD) method.