Crystallization and solidification of scalable metal halide perovskite films for photovoltaics

Metal halide perovskite photovoltaics have emerged as promising next-generation solar technologies owing to their high efficiency and compatibility with low-temperature manufacturing. Although small-area perovskite solar cells have achieved certified efficiencies around 28%, scalable fabrication of large-area perovskite films and modules remains a major challenge for commercialization. During scale-up, film formation becomes highly sensitive to coupled transport and solidification processes, including fluid flow, solvent evaporation, vapor transport, supersaturation evolution, nucleation, crystal growth, and phase conversion. These processes generate spatiotemporal heterogeneities that cause nonuniform crystallization, defect formation, and module-level performance losses. In this Review, we establish a crystallization-centered framework for understanding large-area perovskite film fabrication across both solution-based and vapor-based deposition routes. Solution processing methods are discussed from the perspectives of wet-film hydrodynamics and solvent-mediated crystallization, while vapor-based routes are analyzed in terms of precursor transport, surface reaction kinetics, and non-equilibrium growth. Previous studies are further used to relate precursor transport and perovskite crystallization control to film uniformity, device performance, and operational stability. Finally, we discuss emerging strategies for crystallization control and scalable manufacturing toward reliable, high-throughput perovskite photovoltaic modules.