Tailoring In Situ Healing and Stabilizing Post-Treatment Agent for High-Performance Inverted CsPbI₃ Perovskite Solar Cells with Efficiency of 16.67%

CsPbI3 perovskite solar cells (PSCs) have revealed promising applications for high-performance photovoltaic devices. Despite the high efficiency for regular CsPbI3 PSCs, poor stability for adverse dopants reflects the importance of the inverted. However, the inverted lag far for a phase transition and inferior CsPbI3 films. Here, we report an effective post-treatment agent, methylammonium pyridine-2-carboxylic (MAPyA), to heal and stabilize CsPbI3 films. MAPyA on CsPbI3 can decompose into methylamine (MA) gas and pyridine-2-carboxylate (PyA–) at 100 °C, and MA could remove pinholes, while PyA– gifts effective passivation. In addition, oriented PyA– hinders phase transition and isolates external erosions for long-term stability. The optimized devices show the highest efficiency among the inverted CsPbI3 PSCs of 16.67%. Besides, the phase stability and robustness against external erosions get considerable promotion. More importantly, unpackaged I-rich inorganic PSCs are rarely reported with long-term maximum power point in ambient condition, and our unencapsulated device still retains 81.31% of the initial efficiency after 1800 min of outdoor operation (relative humidity 30%).