SnO ₂ /Perovskite Buried Interfacial Modification for Efficient and Stable Perovskite Solar Cells

Organic-inorganic halide perovskite solar cells (PSCs) with n-i-p architectures exhibit significant potential for commercialization owing to their impressive power conversion efficiency and chemical stability. However, interfacial defects between electron transport layers (ETLs) and perovskite films present a critical challenge that significantly limits the photovoltaic performance. Here, we introduce 5-(trifluoromethyl) pyridine-2-carboxylic acid (TPCA) as a multifunctional interfacial modifier at the SnO₂/perovskite buried interface. TPCA effectively passivates Sn-OH dangling bonds on the SnO₂ surface while modulating surface energy to guide the crystallization of perovskite films. Through this synergistic mechanism combining chemical passivation and physical modulation, the maximum power conversion efficiency (PCE) of perovskite solar cells modified by TPCA has increased from 22.10% to 24.38%. Furthermore, unencapsulated TPCA-treated PSCs maintained 90.7% of their initial efficiency after 1,000 hours, showing superior long-term stability. This work provides a practical interface engineering approach to advance both efficiency and stability in perovskite optoelectronics.