Sulfonic Surfactant Promises Uniform Wide‐Bandgap Perovskite Solar Modules for All‐Perovskite Tandem Photovoltaics

Abstract The development of scalable all‐perovskite tandem solar cells offers a promising pathway for perovskite photovoltaic commercialization. However, the certified efficiency of all‐perovskite tandem mini‐modules still lags much behind their small‐area (≈0.1 cm²) counterparts. This performance gap primarily stems from inhomogeneities and inferior crystallinity in wide‐bandgap (WBG) perovskite solar cells (PSCs) when scaling up. In this work, we introduced 3‐(N, N‐Dimethyloctylammonio) propananesulfonate inner salt (DOPS) as an ionic surfactant additive to suppress pinhole formation and enhance the uniformity of large‐area perovskite films. The well‐designed interaction between DOPS and WBG compositions effectively regulates the crystallization process and passivates the uncoordinated Pb²⁺, resulting in a uniform and high‐quality WBG perovskite film with suppressed non‐radiative recombination. These improvements enable champion efficiencies of 19.57% and 16.38% for WBG PSCs with aperture areas of 1.0 and 20.07 cm², respectively. Furthermore, when integrating this optimized WBG device into all‐perovskite tandem solar cells, it yields impressive PCEs of 27.82% (1.0 cm²) and 23.41% (20.07 cm²). Overall, these findings present an effective strategy for enhancing large‐area uniformity via the surfactant synergistic effect of crystallization regulation and defect passivation.