Active Passivation Charge Transport in n-i-p Perovskite Solar Cells Approaching 26% Efficiency

In n-i-p planar perovskite solar cells (PSCs), the electron transport layer (ETL) and the hole transporting layer play a crucial role in realizing high power conversion efficiency (PCE). Herein, a TiO₂-SDBA-SnO₂ stacked ETL is reported, where 4,4'-sulfonyldibenzoic acid (SDBA) serves as an active passivation agent to suppress charge recombination and enhance interface quality. SDBA effectively passivates oxygen vacancies in sputtered TiO₂, while simultaneously promoting SnO₂ nucleation and improving film quality. Moreover, its molecular structure increases the surface free energy of the ETL, facilitating the formation of high-quality perovskite films with larger grain sizes and fewer defects. As a result, PSCs with this optimized ETL achieve a PCE of 25.94% with excellent stability. This approach also enables the fabrication of perovskite solar modules with a certified efficiency of 22.55% over a 26.02 cm² aperture area.