Passivating SnO₂/Perovskite Interface viaMultisite Chelation for High-Efficiency Perovskite Solar Cells

In n-i-p perovskite solar cells (PSCs) with tin oxide (SnO₂) as the electron transport layer, the SnO₂/perovskite interface serves dual functions: facilitating charge extraction and promoting perovskite crystal growth. However, significant nonradiative recombination, energy misalignment, and suboptimal interfacial bonding at the SnO₂/perovskite interface result in efficiency loss and compromised stability. In this work, sulfonyl diimidazole (SDI) was introduced as a surface modifier for SnO₂. SDI acts as a dual-modifier at the buried interface, binding strongly to both the SnO₂ and perovskite layers. SDI effectively passivates SnO₂ surface defects, optimizes band arrangement for better interfacial contact, and facilitates perovskite growth. This effectively promotes charge carrier transport, inhibits charge carrier recombination, and alleviates the film strain. The SDI-incorporated device demonstrated an improved power conversion efficiency (PCE) of 23.31%, surpassing the control device’s efficiency of 21.61%, alongside an elevation in fill factor from 77.3% to 81.56%. The optimized device demonstrates a 90% retention of its initial PCE after enduring 1000 h of aging, significantly outlasting the pristine SnO₂-based counterpart. Consequently, the modification of interfaces utilizing SDI represents a viable approach to enhance the interface characteristics, elevate the quality of crystallization, and achieve high-performance PSCs.