A comprehensive insight into deep-level defect engineering in antimony chalcogenide solar cells

Antimony chalcogenides (Sb2X3, X = S and Se) are intriguing materials for the fabrication of next-generation, flexible/wearable, lightweight, and tandem photovoltaic (PV) devices. Recently, the power conversion efficiency (PCE) of 10.75% and 11.66% has been demonstrated in (single junction) Sb2X3 and Sb2X3/Si (tandem) solar cells, respectively. However, the inevitable presence (>1016 cm−3) of deep-level defects (especially SbS and SbSe antisites) induces Fermi-level (EF) pinning, accelerates Shockley–Read–Hall (SRH) recombination, and shortens the carrier lifetime. Unambiguously, these defects result in sluggish charge transport and high open-circuit voltage (VOC) deficits in the corresponding Sb2X3 solar cells. Therefore, a comprehensive understanding of the deep-level defects and their passivation strategies can be instrumental in reducing the VOC deficits and boosting the PCE values. In this regard, the present review highlights the expanding toolbox of defect-engineering strategies for Sb2X3 films, laying a solid foundation for improving the PCE of Sb2X3 solar cells.