Selective Passivation of Buried Interface in Perovskite Solar Cells via Ultrafast Photoexcitation

Perovskites have emerged as a leading candidate material for next‐generation photovoltaics, owing to exceptional optoelectronic characteristics such as high absorption coefficients, extended carrier diffusion length, and bandgap tunability, as well as low‐cost solution‐processability. However, critical issues persist at the buried interface between perovskite and charge transport layers, including uncoordinated ions, pinhole defects, and energy level mismatches. These defects trigger severe nonradiative recombination and ion migration, fundamentally limiting the device efficiency and stability. Herein, we propose a selective passivation strategy of perovskite/electron transport layer buried interface via ultrafast photoexcitation by direct irradiation from the glass side with femtosecond laser pulses. At the optimal femtosecond pulse irradiation fluence, the buried interface between perovskite and tin oxide is directly treated to suppresses interface recombination centers, reduces the electron extraction time, and increases the short‐circuit current density ( J sc ), thereby optimizing the charge transport efficiency. The small‐area devices achieved a power conversion efficiency (PCE) of 24.18% and retained 98% of its initial PCE after 700‐h aging, while a mini‐module attained a PCE of 15.58%. This method paves the way for the efficient and stable fabrication of perovskite solar cells toward industrialization, offering critical technical support for their commercialization.