Synergistic Engineering of Buried Interfaces for High-Efficiency and Stable Perovskite Solar Cells

Abstract

To address the challenges of interfacial defects and energy-level alignment in perovskite solar cells (PSCs), this study introduces p-toluenethiol as a molecular modifier for the SnO₂/perovskite buried interface. The thiol groups (–SH) coordinate with oxygen vacancies and hydroxyl groups on the SnO₂ surface, effectively passivating deep-level trap states and suppressing the formation of PbI₂ secondary phases and lattice defects. The aromatic benzene ring induces interfacial dipole moments via π-conjugation, optimizing energy-level alignment between SnO₂ and perovskite to reduce electron transport barriers, and its hydrophobicity also enhances the device's environmental stability. Experimental results show that PSCs achieve a power conversion efficiency (PCE) of 25.53%, while flexible devices exhibit a PCE of 23.27%. Stability tests demonstrate significantly improved performance retention under continuous illumination and environmental exposure. This work synergistically optimizes device efficiency and stability through molecular-scale interfacial engineering, providing a foundation for the application of perovskite solar cells.