Comparative analysis of substrate and superstrate configurations in Sb₂S₃ thin-film solar cells by numerical modelling

This study systematically analyses the performance differences between superstrate and substrate configurations in Sb₂S₃ thin-film solar cells using comprehensive numerical simulations. Factors such as absorber thickness, radiative recombination, defect density, operating temperature, and series and shunt resistances are examined for their impact on power conversion efficiency (PCE) and external quantum efficiency (EQE). Results indicate that superstrate configurations achieve higher efficiencies with thinner absorber layers compared to substrate configurations. At an optimal absorber thickness of 3 µm, the superstrate configuration exhibits a PCE of 20.34%, V_oc of 1.1175 V, J_sc of 21.38 mA cm⁻², and FF of 85.16%. In contrast, the substrate configuration shows a PCE of 18%, V_oc of 1.121 V, J_sc of 22.12 mA cm⁻², and FF of 72.58%. Radiative recombination significantly impacts FF, influencing the efficiency differences. Superstrate designs are less sensitive to variations in shunt and series resistances and perform robustly across a wider range of resistance values. While superstrates generally perform better at higher temperatures, their efficiency declines more steeply with further temperature increases compared to substrates. This simulation-based analysis highlights the superior performance of superstrate configurations and provides a foundation for future empirical research and optimization in thin-film solar cell technology.