Performance enhancement of Sb2Se3 solar cell using a back surface field layer: A numerical simulation approach

In the present work, antimony selenide (Sb2Se3)-based solar cell with a back surface field (BSF) layer has been designed and studied. The purpose of this research is to improve the performance of the Sb2Se3-based solar cell by introducing low-cost and widely available barium silicide (BaSi2) material as the BSF layer into the basic Sb2Se3-based heterojunction solar structure. A comparative study on the performance of the conventional Sb2Se3 solar cell structure consisting of Al/FTO/CdS/Sb2Se3/Mo and the proposed structure of Al/FTO/CdS/Sb2Se3/BaSi2/Mo is made. The photovoltaic parameters such as open circuit voltage, short-circuit current density, fillfactor, power conversion efficiency, and quantum efficiency of heterojunction structures are analyzed intensively by using the Solar Cell Capacitance Simulator in One Dimension (SCAPS-1D) program. To optimize the device, the thickness of Sb2Se3 absorber layer is varied from 0.1 to 2 mu m. In addition, the effects of acceptor ion and bulk defect densities in Sb2Se3 absorber layer, interface defect density of buffer/absorber and absorber/BSF, back surface recombination velocity, operating temperature, and cell resistances on the overall performances are investigated. The thicknesses of BaSi2 BSF and Sb2Se3 absorber layers are optimized to be 0.3 mu m and 1 mu m, respectively. The efficiency of the proposed solar structure with a thin 1 mu m Sb2Se3 absorber layer is obtained to be 29.35%. The simulation results lead to suggest that the BaSi2 material as a BSF layer would be effective to fabricate low cost and high-efficient Sb2Se3-based thin-film solar cells.