AbstractMetal‐halide perovskite solar cells (PSCs) have emerged as a promising photovoltaic technology. Fabricating PSCs in ambient air can accelerate their low‐cost commercialization, since it can remove the reliance on atmosphere‐controlled equipment. However, the power conversion efficiency (PCE) of air‐fabricated PSCs still lags behind those fabricated in glovebox. Here, based on a technology to fabricate high‐quality perovskite film in ambient air, a compatible optimization is performed on electron transport layer (ETL) to further enhance the photovoltaic performance of PSCs. A soft‐templated deposition strategy is proposed that utilizes tetrasodium glutamate diacetate (GLDA) to finely regulate the chemical bath deposition process, leading to an ideal SnO₂ ETL with no additive residual. Adopting this feature of no residual, a molecular bridge using β‐guanidinopropionic acid (βA) is constructed at the buried interface (SnO₂/perovskite), which effectively enhances the electron extraction and decreases electron losses. The resulting PSCs (0.08 cm²) achieve an impressive PCE of 25.74% (certificated 25.43%), which is the highest among the air‐fabricated PSCs reported to date. A PCE of 24.61% in 1 cm²‐PSCs is also obtained, exhibiting the scalable potential of the technology. In addition, the excellent operational stability of these PSCs is also demonstrated.