Tin-based perovskite solar cells (TPSCs) have received great attention due to their eco-friendly properties and high theoretical efficiencies. However, the fast crystallization feature of tin-based perovskites leads to poor film quality and limits the corresponding device performance. Herein, a chlorofullerene, C₆₀Cl₆, with six chlorine attached to the C₆₀ cage, is applied to modulate the crystallization process and passivate grain boundary defects of the perovskite film. The chemical interactions between C₆₀Cl₆ and perovskite components retard the transforming process of precursors to perovskite crystals and obtain a high-quality tin-based perovskite film. It is also revealed that the C₆₀Cl₆ located at the surfaces and grain boundaries can not only passivate the defects but also offer a role in suturing grain boundaries to suppress the detrimental effects of water and oxygen on perovskite films, especially the oxidation of Sn²⁺ to Sn⁴⁺. As a result, the C₆₀Cl₆-based device yields a remarkably improved device efficiency from 10.03% to 13.30% with enhanced stability. This work provides a new strategy to regulate the film quality and stability of TPSCs using functional fullerene materials.

Fullerene materials have been widely used to fabricate efficient and stable perovskite solar cells (PSCs) due to their excellent electron transport ability, defect passivation effect, and beyond. Recent studies have shown that fullerene-related chemical interaction has played a crucial role in determining device performance. However, the corresponding fullerene-related chemical interactions are yet well understood. Herein, a comprehensive review of fullerene materials in regulating carrier transport, passivating the surface and grain boundary defects, and enhancing device stability is provided. Specifically, the influence of the fullerene-related chemical interactions, including fullerene-perovskite, fullerene-inorganic electron transport layer (IETL), and fullerene-fullerene, on the device performance is well discussed. Finally, we outline some perspectives for further design and application of fullerene materials to enhance the performance and commercial application of PSCs.