Molecular surface n-doping enables 22% efficient and highly stable inverted perovskite solar cells under 60% humidity

The fabrication of inverted perovskite solar cells (IPSCs) under high-humidity air conditions holds great potential for future industrial applications. However, high humidity imposes significant challenges for obtaining high-quality perovskite films, as it increases surface defects, induces nonradiative recombination, and ultimately degrades the performance of IPSCs. Here, we introduced pyridine-2,6-diamide (PDBA) as an n-type semiconductor to enable the fabrication of high-performance IPSCs in ambient air with a relative humidity ∼60%. The PDBA molecule, consisting of a pyridine ring and amide groups, interacts strongly with uncoordinated Pb²⁺ ions on the perovskite surface lattice, effectively reducing additional p-type defects at the perovskite/air interface, suppressing carrier recombination, and thereby markedly enhancing the device performance. Under this air condition, the PDBA-treated Perovskite Solar Cells (PSCs) achieved a PCE of 22%, maintaining 93% of their initial efficiencies after 800 h aging under the International Summit on Organic Photovoltaic Stability (ISOS) protocols ISOS-L-2I, demonstrating excellent long-term stability. This study presents a molecular surface n-doping strategy that enables efficient and stable IPSCs under high-humidity air conditions, thereby providing a promising pathway toward their practical industrial development.