Improved crystallinity and self-healing effects in perovskite solar cells via functional incorporation of polyvinylpyrrolidone

Abstract Air moisture is the key issue for perovskites which invades the films and accelerates the damage of devices. Here, polyvinylpyrrolidone (PVP) is introduced to the methylammonium lead iodide (MAPbI3) perovskite precursor to control crystal growth and endow the devices with self-healing ability in a moisture environment. The strong C=Ο⋅⋅⋅Η−Ν hydrogen bonding interactions between PVP and MAPbI3 was confirmed by nuclear magnetic resonance measurements. By introducing hydrogen bonding in the MAPbI3-based PSCs, we form a compact perovskite film of excellent electronic quality with a power conversion efficiency (PCE) of up to 20.32%. Furthermore, the Ο⋅⋅⋅Η−Ν hydrogen bonding interactions at the grain boundaries suppress the decomposition of methylammonium cations and improve the recyclable dissolution-recrystallization of perovskite. As a result, the MAPbI3-PVP based cells exhibited striking moisture stability and self-healing behavior, with negligible decay in efficiency after 500 h of operation in high humidity (65±5% relative humidity) and rapid recovering ability after their removal from the humid environment.