Two-Dimensional Cs(3)Sb(2)I(9−x)Cl(x) Film with (201) Preferred Orientation for Efficient Perovskite Solar Cells

All-inorganic Sb-perovskite has become a promising material for solar cell applications owing to its air stability and nontoxic lead-free constitution. However, the poor morphology and unexpected (001) orientation of Sb-based perovskite films strongly hinder the improvement of efficiency. In this work, two-dimensional Cs(3)Sb(2)Cl(x)I(9−x) with (201) preferred orientation has been successfully fabricated by introducing thiourea (TU) to the precursor solution. The presence of the C=S functional group in TU regulates the crystallization dynamics of Cs(3)Sb(2)I(9−x)Cl(x) films and generates the (201) preferred orientation of Cs(3)Sb(2)Cl(x)I(9−x) films, which could effectively improve the carrier transport and film morphology. As a result, the Cs(3)Sb(2)I(9−x)Cl(x) perovskite solar cells (PSCs) delivered a power conversion efficiency (PCE) of 2.22%. Moreover, after being stored in nitrogen at room temperature for 60 days, the devices retained above 87.69% of their original efficiency. This work demonstrates a potential pathway to achieve high-efficiency Sb-based PSCs.