Solar energy is one of the most common renewables and environment-friendly energy sources that are currently undergoing rapid research and implementation to fulfill rising global energy demand, owing to its relative abundance. Furthermore, the growing usage of solar energy necessitates the advancement of innovative and efficient photovoltaic (PV) technologies with lower production prices and improved power conversion efficiency (PCE). Antimony selenide is the chemical compound with the formula Sb₂Se₃ which crystallizes in an orthorhombic space group. These non-toxic and earth-abundant materials are having a high absorption coefficient (>10⁵ cm^-1) and optimal bandgap (1.2 eV). Sb₂Se₃ is a very promising solar absorber material because of these attractive material, optical and electrical properties and it has become a popular PV absorber, with power conversion efficiency rising gradually compared to other developing compounds. The main objective of this work is to replace the commonly used toxic CdS as buffer layer. Here, a non-toxic buffer layer ZnSe is used and the efficiency of solar cell has be determined by varying the thickness and carrier concentration of buffer and absorber materials and their effect on efficiency is analyzed. A solar cell capacitance simulator in 1 dimension (SCAPS-1D) software has explored of the solar-cell properties of the antimony selenide (Sb₂Se₃).