Numerical Investigation of Interfacial Defects, BSF Layer, and Parasitic Resistances in CBTSSe ThinFilm Solar Cells Using SCAPS-1D

Abstract

This study employs SCAPS-1D numerical modeling to investigate performance limitations in Cu<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>BaSn(S,Se)<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> (CBTSSe) thin-film solar cells. The simulations are benchmarked against experimental J–V data, demonstrating strong agreement and validating the framework. The analysis reveals that elevated defect densities at the CdS/CBTSSe interface degrade device metrics, particularly open circuit voltage (Voc), short-circuit current (Jsc), fill factor (FF), and overall efficiency (η). To counteract recombination at the rear contact, a CdTe back-surface field (BSF) layer is introduced, which enhances carrier extraction. In addition, systematic variation of parasitic resistances highlights their critical role in determining conversion efficiency, underlining the necessity of optimized contact design. These results provide practical guidance for improving the architecture of CBTSSebased photovoltaic devices.