Defect passivation with Pb for high-performance Sb2S3 solar cells via vapor transport deposition

Antimony sulfide (Sb 2 S 3 ) has emerged as a promising absorber material for thin-film solar cells due to its excellent light absorption properties. However, its inherent quasi-one-dimensional crystal structure and complex defect landscape severely limit device V OC and J SC . In this study, lead-doped Sb 2 S 3 was achieved through an ion exchange method, and Sb 2 S 3 :Pb thin films were subsequently prepared via vapor transport deposition(VTD). The incorporation of Pb doping promoted preferential [hk1] orientation growth, facilitating vertical carrier transport channels across the substrate. Concurrently, it significantly reduced the Urbach energy, enhanced carrier concentration, and effectively suppressed non-radiative recombination through the formation of shallow-level Pb Sb defects alongside reduced defect density of deep-levlel Sb i . The optimized device achieved V OC of 709 mV, J SC of 12.99 mA/cm 2 , and a power conversion efficiency of 5.22%, establishing a new record efficiency for Sb 2 S 3 solar cells fabricated by VTD. This work provides an effective strategy for improving Sb 2 S 3 thin-film quality through cation doping and advances its development in photovoltaic applications.