Abstract A novel cooperative regulatory strategy is proposed in this work to optimize the crystallization dynamics of Formamidinium (FA)‐based perovskite materials, which is achieved by meticulously incorporating the organic molecule guanidinium (GA + ) and the high boiling point organic solvents N ‐Methyl‐2‐Pyrrolidone (NMP) into the perovskite precursor solution synergistically. This findings indicated that the GA + doping strategy (G‐DS) is toward to inhibits the formation of α‐phase perovskite crystals owing to its larger ionic radius, thereby promoting the formation of perovskite films with enlarged grain size. Simultaneously, the NMP‐doping strategy (N‐DS) has assisted controllable crystallization dynamics in as‐cast films by optimizing nucleation density and crystal growth rate through a delayed supersaturated environment induced re‐dissolution function. Briefly, it can assume that the crystallization dynamics dual modulation strategy enables the realization of high‐quality perovskite film with micro‐meter sized perovskite grain, appropriate internal strain and a compact, dense surface texture. The optimized films therefore exhibits powerful exciton separation energy, suppressed charge carrier recombination and reduces series resistance, leading to a remarkable champion power conversion efficiency (PCE) of 25.38% and exceptional reliability, retaining 93.09% of their initial PCE after storage the unencapsulated devices in a moisture‐rich environment for 2160 h.

Regulating the Perovskite Crystallization Dynamics Via Dual Modulation Strategy for Performance Enhancement of Perovskite Solar Cells