Efficient In Situ Sulfuration Process in Hydrothermally Deposited Sb₂S₃ Absorber Layers

Sulfuration plays a decisive role in enhancing crystal growth and passivate defects in the fabrication of high-efficiency metal-sulfide solar cells. However, the traditional sulfuration process always suffers from high-price professional equipment, tedious processes, low activity of S, or high toxicity of H₂S. Here, we develop a desired in situ sulfuration by introducing tartaric acid additive into the hydrothermal deposition process of Sb₂S₃. Tartaric acid, sodium thiosulfate, and potassium antimony tartaric can form Sb₂S-contained (x > 3) as-prepared films. Encouragingly, the annealing becomes an inspiring in situ sulfuration process, which can obtain a more compact absorber layer. In addition, the crystallinity and defect property of the Sb₂S₃ film are also improved significantly. Finally, we achieve a high-performance Sb₂S₃ solar cell with a power conversion efficiency of 6.31%, which shows an encouraging enhancement of ∼15% compared with the traditional hydrothermal process. This study provides an innovative way to prepare high-efficiency Sb₂S₃ solar cells and provides a desirable guide to realize the in situ sulfuration process.