In situ fabrication of 2D SnS2 nanosheets as a new electron transport layer for perovskite solar cells

To promote commercialization of perovskite solar cells (PSCs), low-temperature processed electron transport layer (ETL) with high carrier mobility still needs to be further developed. Here, we reported two-dimensional (2D) tin disulfide (SnS2) nanosheets as ETL in PSCs for the first time. The morphologies of the 2D SnS2 material can be easy controlled by the in situ synthesized method on the conductive fluorine-doped tin oxide (FTO) substrate. We achieved a champion power conversion efficiency (PCE) of 13.63%, with the short-circuit current density (JSC) of 23.70 mA/cm2, open-circuit voltage (VOC) of 0.95 V, and fill factor (FF) of 0.61. The high JSC of PSCs results from effective electron collection of the 2D SnS2 nanosheets from perovskite layer and fast electron transport to the FTO. The low VOC and FF are the results of the lower conduction band of 2D SnS2 (4.23 eV) than that of TiO2 (4.0 eV). These results demonstrate that 2D material is a promising candidate for ETL in PSCs.