The study investigates the transport phenomena and recombination mechanisms in thin-film Sb₂S₃ solar cells to improve their efficiency. The Shockley–Queisser (SQ) limit of 28.64% is significantly higher than the current record power conversion efficiency (PCE) of 8.00% for Sb₂S₃ solar cells. The primary cause of this gap is interface-induced recombination losses due to defects at the interfaces and misaligned energy levels. The research employs an analytical model to investigate various recombination mechanisms, including non-radiative recombination, Sb₂S₃/CdS interface recombination, Auger recombination, surface recombination, tunneling-enhanced recombination, and their combined effects on solar cell performance. The model is validated against experimental data from a Glass/ITO/CdS/Sb₂S₃/Au solar cell, showing good agreement. The study examines the impact of parameters such as thickness, doping, electronic affinity, and bandgap on solar cell performance. It also analyzes the effect of bulk traps in CdS and Sb₂S₃ and interfacial traps on key solar cell parameters, including carrier minority lifetime, diffusion length, and surface recombination velocity. The optimized solar cell configuration demonstrates a significant improvement in performance, achieving a short-circuit current (JSC) of 47.9 mA/cm², an open-circuit voltage (VOC) of 1.16 V, a fill factor (FF) of 54%, and a conversion efficiency of 11.68%, a 30% increase over conventional solar cells. The optimized design also enhances reliability by mitigating interfacial traps at the CdS/Sb₂S₃ interface through improved band alignment control and parameter optimization. The findings provide valuable insights into the underlying processes governing Sb₂S₃-based photovoltaic devices and contribute to advancing the efficiency and stability of Sb₂S₃ solar cells.The study investigates the transport phenomena and recombination mechanisms in thin-film Sb₂S₃ solar cells to improve their efficiency. The Shockley–Queisser (SQ) limit of 28.64% is significantly higher than the current record power conversion efficiency (PCE) of 8.00% for Sb₂S₃ solar cells. The primary cause of this gap is interface-induced recombination losses due to defects at the interfaces and misaligned energy levels. The research employs an analytical model to investigate various recombination mechanisms, including non-radiative recombination, Sb₂S₃/CdS interface recombination, Auger recombination, surface recombination, tunneling-enhanced recombination, and their combined effects on solar cell performance. The model is validated against experimental data from a Glass/ITO/CdS/Sb₂S₃/Au solar cell, showing good agreement. The study examines the impact of parameters such as thickness, doping, electronic affinity, and bandgap on solar cell performance. It also analyzes the effect of bulk traps in CdS and Sb₂S₃ and interfacial traps on key solar cell parameters, including carrier minority lifetime, diffusion length, and surface recombination velocity. The optimized solar cell configuration demonstrates a significant improvement in performance, achieving a short-circuit current (JSC) of 47.9 mA/cm², an open-circuit voltage (VOC) of 1.16 V, a fill factor (FF) of 54%, and a conversion efficiency of 11.68%, a 30% increase over conventional solar cells. The optimized design also enhances reliability by mitigating interfacial traps at the CdS/Sb₂S₃ interface through improved band alignment control and parameter optimization. The findings provide valuable insights into the underlying processes governing Sb₂S₃-based photovoltaic devices and contribute to advancing the efficiency and stability of Sb₂S₃ solar cells.