Constructing water-resistant CH3NH3PbI3 perovskite films via coordination interaction

Abstract

Organic–inorganic halide CH₃NH₃PbI₃ (MAPbI₃) perovskite solar cells (PSCs) have attracted intensive attention due to their high power conversion efficiency and low fabrication cost. However, MAPbI₃ is known to be very sensitive to humidity, and the intrinsic long-term stability of the MAPbI₃ film remains a critical challenge. 2-Aminoethanethiol (2-AET) was used as a ligand to bridge the organic compound (MAI) and inorganic compound (PbI₂), which restricted the fast growth of PbI₂ to realize the synchronous growth environment of MAI and PbI₂ crystals, resulting in the formation of a compact MAPbI₃ film with polygonal grains. Due to the compact (PbI₂)–2-AET–(MAI) molecule barrier layers in the MAPbI₃ structure, the resulting perovskite films showed excellent intrinsic water-resistance, with the MAPbI₃ perovskite crystal structure retained for a long time (>10 minutes) after immersion in water. This work makes a step towards obtaining long-term stable MAPbI₃ perovskite devices.