Reducing the MAPbI3 microstrain by fast crystallization

Control over perovskite crystal growth, resulting in thin film morphology, has been at the very foundation of the evolution of perovskite photovoltaics (PVs). Methylammonium lead triiodide (MAPbI3) perovskite has been the workhorse material for this class of semiconductors, offering good efficiency with a relatively simple composition, which attracts industrial scale production. Despite that, instability has hampered their further exploitation. In this work, we explored the effect of different types and timing of the antisolvents on MAPbI3 perovskite crystallization. This approach enabled control of the crystalline microstrain while reducing unwanted trap density. This effect impacted device performances, enabling the achievement of MAPbI3 solar cell with power conversion efficiency (PCE) approaching 22%. Importantly, we demonstrated that an efficient MAPbI3 perovskite solar cell is also a stable one. Our solar cells showed an efficiency loss of only 10% after 900 h at 85°C, putting MA-based PSCs back among promising PV technologies.