Perovskites with superior optoelectronic properties are admirable candidates for high-performance light-emitting diode (LED) applications. However, the use of antisolvents during perovskite film fabrication increases process complexity and production costs, as well as raises toxicity concerns. Here, we demonstrated an antisolvent-free crystallization strategy enabled by intermediate stabilization for the fabrication of high-quality perovskite films. We prepared the reduced-dimensional perovskite precursor, and used cesium bromide as the crystallization retardant to facilitate the formation of stable intermediate during spin coating. This intermediate directs more ordered crystal growth and achieves a uniform quantum well thickness distribution, thereby substantially enhancing film quality. By using this approach, we fabricated LEDs with a maximum external quantum efficiency of 29.36%. This work elucidates the crystallization mechanism of perovskites and establishes an antisolvent-free pathway for the scalable and sustainable fabrication of high-performance perovskite optoelectronic devices.