Kinetic Regulation of Intercalation-Assisted Crystallization in Hybrid Evaporation–Solution Perovskite Solar Cells

Hybrid evaporation-solution processing offers a promising route for high-efficiency perovskite solar cells; however, the dense lead iodide (PbI2) framework leads to competing intercalation and dissolution-recrystallization pathways, resulting in incomplete conversion and limited device performance. Here, we report a kinetic regulation strategy using propylamine hydrochloride (PACl) to control crystallization dynamics in hybrid evaporation-solution perovskite films. We show that PACl slows the initial reaction kinetics, enabling more complete ammonium salt infiltration while promoting an intercalation-dominated conversion pathway. This regulated process suppresses excessive PbI2 dissolution and induces a preferential (100)-oriented perovskite texture, leading to improved film uniformity and crystalline quality. In situ characterization combined with density functional theory calculations reveals that PA+ selectively adsorbs on PbI2 surfaces and forms directional hydrogen bonds, stabilizing the layered framework while modulating interfacial reaction kinetics. The synergy between interfacial kinetic control and structural stabilization enables high-quality crystallization with reduced defect formation. As a result, the optimized devices achieve a high power conversion efficiency of 25.13% and exhibit good operational stability, maintaining performance over 900 h of maximum power point tracking. This work provides fundamental insight into crystallization pathway regulation in hybrid deposition systems and offers a general strategy for fabricating oriented, high-performance perovskite films.