Spin‐Coating Free Fabrication of α‐FAPbI 3 ‐Based Efficient Inverted Perovskite Solar Cells via Mixed Self‐Assembled Molecules

Abstract The α‐phase formamidinium lead iodide (α‐FAPbI 3 ) perovskite has a near‐ideal bandgap approaching the Shockley–Queisser limit, yet its full potential remains underexploited in inverted perovskite solar cells (PSCs), particularly those fabricated by scalable blade‐coating methods. One of the key reasons is that the hole transport layer (HTL) cannot yet fully match the requirements of blade‐coated α‐FAPbI 3 . Herein, an approach of mixing amino acid derivatives with traditional self‐assembled molecules (SAM) to form mixed‐SAMs is applied to enable full blade‐coating of high‐quality HTLs and α‐FAPbI 3 films, and to realize a “four‐in‐one effect,” encompassing enhanced anchoring, improved film formation, defect passivation, and optimized energy level alignment. Devices incorporating 1‐Guanidineacetic acid as the co‐assembled SAM component exhibit power conversion efficiencies (PCEs) of 25.43% (3.5 mm 2 ) and 22.94% (6.25 cm 2 mini‐modules), respectively. The unencapsulated device retained 90.4% of its initial PCE after 3048 h of thermal aging at 85 ± 2 °C in N 2 atmosphere. This work provides a feasible approach toward scalable solution‐processed α‐FAPbI 3 ‐based PSCs with high performance.