Constructing water-resistant CH3NH3PbI3 perovskite films via coordination interaction

Organic-inorganic halide CH3NH3PbI3 (MAPbI(3)) perovskite solar cells (PSCs) have attracted intensive attention due to their high power conversion efficiency and low fabrication cost. However, MAPbI(3) is known to be very sensitive to humidity, and the intrinsic long-term stability of the MAPbI(3) 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 MAPbI(3) film with polygonal grains. Due to the compact (PbI2)-2-AET-(MAI) molecule barrier layers in the MAPbI(3) structure, the resulting perovskite films showed excellent intrinsic water-resistance, with the MAPbI(3) perovskite crystal structure retained for a long time (>10 minutes) after immersion in water. This work makes a step towards obtaining long-term stable MAPbI(3) perovskite devices.