A practical method for fabricating perovskite solar cells with remarkable water resistance via additive engineering

Hybrid inorganic–organic perovskite solar cells (PSCs) have attracted significant attention in the recent years due to their excellent photoelectric properties. However, the fast degradation of perovskite solar cells under humid environment restricts their industrial applications. Herein, we discovered that the hybrid organic–inorganic perovskite films remain undecomposed in water after adding 2-aminoethanethiol hydrochloride (2-AET·HCl) as S in 2-AET·HCl can fix the methylamine vacancies and coordinate with Pb in the material, thus protecting the perovskite film from water. The optimal Cs0.15MA0.85PbI3·(0.578)2-AET perovskite film generates a device with a fill factor of 0.68, yielding a power convention efficiency (PCE) of 1.1% after immersion in water. This is the first time where PSCs with high water resistance have been realized without inserting hydrophobic layers, which provides a new approach to enhance the capability of water resistance for PSCs.