Additive-Assisted Hydrothermal Growth Enabling Defect Passivation and Void Remedy in Antimony Selenosulfide Solar Cells.

Antimony selenosulfide (Sb 2 (S,Se) 3 ) has recently emerged as a promising light-absorbing material, attributed to its tunable photovoltaic properties, low toxicity, and robust environmental stability. However, despite these advantages, the current record efficiency for Sb 2 (S,Se) 3 solar cells significantly lags behind their Shockley-Queisser limit, especially when compared to other well-established chalcogenide-based thin-film solar cells, such as CdTe and Cu(In,Ga)Se 2 . This underperformance primarily arises from the formation of unfavorable defects, predominately located at deep energy levels, which act as recombination centers, thereby limiting the potential for performance enhancement in Sb 2 (S,Se) 3 solar cells. Specifically, deep-level defects, such as sulfur vacancy (V S ), have a lower formation energy, leading to severe non-radiative recombination and compromising device performance. To address this challenge, thioacetamide (TA), a sulfur-containing additive is introduced, into the precursor solution for the hydrothermal deposition of Sb 2 (S,Se) 3 . This results indicate that the incorporation of TA helps in passivating deep-level defects such as sulfur vacancies and in suppressing the formation of large voids within the Sb 2 (S,Se) 3 absorber. Consequently, Sb 2 (S,Se) 3 solar cells, with reduced carrier recombination and improved film quality, achieved a power conversion efficiency of 9.04%, with notable improvements in open-circuit voltage and fill factor. This work provides deeper insights into the passivation of deep-level donor-like V S defects through the incorporation of a sulfur-containing additive, highlighting pathways to enhance the photovoltaic performance of Sb 2 (S,Se) 3 solar cells.