An Optimization Path for Sb₂(S,Se)₃ Solar Cells to Achieve an Efficiency Exceeding 20

Antimony selenosulfide, denoted as Sb₂(S,Se)₃, has garnered attention as an eco-friendly semiconductor candidate for thin-film photovoltaics due to its light-absorbing properties. The power conversion efficiency (PCE) of Sb₂(S,Se)₃ solar cells has recently increased to 10.75%, but significant challenges persist, particularly in the areas of open-circuit voltage (V_oc) losses and fill factor (FF) losses. This study delves into the theoretical relationship between V_oc and FF, revealing that, under conditions of low V_oc and FF, internal resistance has a more pronounced effect on FF compared to non-radiative recombination. To address V_oc and FF losses effectively, a phased optimization strategy was devised and implemented, paving the way for Sb₂(S,Se)₃ solar cells with PCEs exceeding 20%. By optimizing internal resistance, the FF loss was reduced from 10.79% to 2.80%, increasing the PCE to 12.57%. Subsequently, modifying the band level at the interface resulted in an 18.75% increase in V_oc, pushing the PCE above 15%. Furthermore, minimizing interface recombination reduced V_oc loss to 0.45 V and FF loss to 0.96%, enabling the PCE to surpass 20%. Finally, by augmenting the absorber layer thickness to 600 nm, we fully utilized the light absorption potential of Sb₂(S,Se)₃, achieving an unprecedented PCE of 26.77%. This study pinpoints the key factors affecting V_oc and FF losses in Sb₂(S,Se)₃ solar cells and outlines an optimization pathway that markedly improves device efficiency, providing a valuable reference for further development of high-performance photovoltaic applications.