Sulfamoylbenzoic Acid Derivatives as Molecular Additives through Fine Dipole Moment Regulation for Highly...

An excellent reproducibility of high-quality perovskite thin films is imperative for the commercialization of perovskite solar cells. Multifunctional additive engineering is a promising strategy to tackle this challenge as it facilitates simultaneous control over crystallization processes and defect passivation. Here, an innovative strategy is proposed, leveraging -OH, -NH₂, and -Cl to precisely tune the dipole moment and electronic configuration of multifunctional modified 4-chloro-3-sulfonamide benzoic acid (CSBA) through substituent inductive and conjugation effects. The CSBA derivatives were applied as molecular additives to optimize the chemical interaction with undercoordinated Pb²⁺ and FAI, thereby modulating the defects and crystallization dynamics of perovskite. The results demonstrate that all three additives exhibited synergistic effects, among which -OH-substituted OH-CSBA significantly retards the crystallization process, correlating with its larger dipole moment relative to NH₂-CSBA and Cl-CSBA. This is conducive to obtaining large grain size and low-defect density perovskite films. Consequently, the device based on OH-CSBA exhibits an optimal power conversion efficiency (PCE) of 25.39%, along with high reproducibility and remarkable stability.