Efficient control of crystallization and defects of perovskite films are the key factors toward the performance and stability of perovskite solar cells (PSCs), especially for the preparation of large-area PSCs devices. Herein, we directly embedded surfactant-like monoammonium zinc porphyrin (ZnP) compound into the methylammonium (MA(+)) lead iodide perovskite film to blade-coat large-area uniform perovskite films as large as 16 cm(2). Efficiency as high as 18.3% for blade-coating large-area (1.96 cm(2)) PSCs with ZnP was unprecedentedly achieved, while the best efficiency of fabricated small-area (0.1 cm(2)) device was up to 20.5%. The detailed analyses demonstrated the functions of ZnP in crystallization control and defects passivation of perovskite surfaces and grain boundaries. As a consequence, the ZnP-encapsulated devices retained over 90% of its initial efficiency after 1000 h with a humidity of about 45% at 85 degrees C. This research presents a facile way to achieve the synergistic effect of large area coating, morphology tailoring, and defect suppression based on the molecular encapsulation strategy for perovskite films, further improving the photovoltaic performance and stability of PSCs.