25.91%‐Efficiency and Durable Inverted Perovskite Solar Cells Enabled by a Multifunctional Molecule Mediated Precursor Engineering

Abstract The stability of the precursor is essential for producing high‐quality perovskite films with minimal non‐radiative recombination. In this study, methionine sulfoxide (MTSO), which features multiple electron‐donation sites, is strategically chosen as a precursor stabilizer and crystal growth mediator for inverted perovskite solar cells (PSCs). MTSO stabilizes the precursor by inhibiting the oxidation of iodide ions and passivates charged traps through coordination and hydrogen bonding interactions. This leads to enhanced crystallinity, reduced non‐radiative recombination, and decreased internal residual stress in perovskite film. As a result, remarkable power conversion efficiencies of 25.91% (certified 25.76%) with a minimal voltage deficit of 0.36 V for a 0.09‐cm² inverted PSC, and 21.96% for a 12.96‐cm² (active area) perovskite minimodule, have been achieved, respectively. Furthermore, the unencapsulated devices demonstrated excellent long‐term thermal aging and operational stability, retaining over 90% and 92% of their original efficiencies after 500 h of continuous thermal aging at 85 °C and 2500 h of continuous maximum power point tracking under 1 sun (white light LED array) illumination at 30 ± 5 °C. This study underscores the importance of the rational design of functional molecules for stabilizing the precursor and regulating the crystallization of perovskite films, advancing the practical development of PSCs.