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

Abstract

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 Sb_S and Sb_Se antisites) induces Fermi-level (E_F) 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 (V_OC) 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 V_OC 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.