Central Core Engineering of Aromatic Carbonyl Molecules Enables Highly Efficient and Stable Perovskite Solar Cells

ABSTRACT Aromatic carbonyl molecules have emerged as highly effective passivation additives for fabricating efficient and stable perovskite solar cells. However, the influence of variations in the central core structure of aromatic carbonyl molecules on the passivation capability of their carbonyl groups remains insufficiently explored, thereby hindering the rational design of aromatic carbonyl‐based passivation additives. To address this limitation, we employed a central‐core engineering strategy to design three structurally similar molecules with different core groups. Through systematic investigation, we found that enhancing the electron‐donating ability of the molecular core increases the electron density on the carbonyl groups, thereby improving their defect‐passivation effectiveness. Consequently, perovskite solar cells incorporating TBPAA with the most electron‐rich core delivered power conversion efficiencies of 26.12% (0.09 cm 2 ) and 22.41% (14.0 cm 2 ), while retaining 95% of their initial efficiency after 1200 h of continuous maximum power point tracking at a temperature of 65°C under 1‐sun illumination (ISOS‐L‐2). This work highlights the critical role of the molecular central core in defect passivation and offers new molecular design guidelines for the development of highly efficient and long‐term stable perovskite photovoltaics.