Interface modification by sulfonamide for high-efficiency and stable perovskite solar cells

Abstract

Tin dioxide (SnO₂) is a promising material for the electron transport layer in n-i-p perovskite solar cells, but its performance is limited by internal defects and band misalignment with the perovskite layer. In this study, para-hydroxybenzenesulfonamide (PCBS) was used to modify the buried interface between SnO₂ and perovskite. The -COOH and S=O groups in PCBS passivate the -OH and Sn in SnO₂, respectively. Meanwhile, the -NH₂ group passivates the excess Pb²⁺ within the perovskite film. The PCBS modification enhances the hydrophobicity of the SnO₂ surface, promoting the growth of high-quality, large-grain perovskite films, thereby significantly suppressing non-radiative recombination in perovskite solar cells (PSCs). Moreover, the PCBS modification introduces better energy-level alignment between the SnO₂ and perovskite layers, enabling more efficient electron extraction. Finally, the PCBS interface enhanced the power conversion efficiency (PCE) of PSCs to 21.47 %. After 1440 h of storage in a N₂ atmosphere, the unencapsulated PSCs with interface alteration kept 93.9 % of their original value. These results indicate that burying the perovskite layer with PCBS is a promising strategy to improve the performance of PSCs.