Crystallization in Minutes: Van der Waals Force-Driven Ultrafast Solution Epitaxial Growth of High-Quality Cs₃Cu₂I₅ Platelets

Single crystals of lead-free halide perovskites exhibit exceptional optical and optoelectronic properties. However, the growth of these high-quality semiconductors often requires time-intensive processes. Here, we introduce a rapid and efficient crystal growth method to produce single-crystalline Cs3Cu2I5 platelets significantly faster, cost-effective, and simpler than previously reported techniques. This approach leverages the rapid crystallization of a Cs3Cu2I5 precursor solution on a cleaved mica surface at a specific temperature. By fine-tuning key crystallization parameters, the size and shape of the crystals can be precisely controlled. Remarkably, despite the rapidity of this growth method, the resulting crystals demonstrate exceptional structural integrity, compositional uniformity, and optical properties, comparable to the highest-quality Cs3Cu2I5 crystals reported to date. This epitaxy-driven rapid crystallization strategy represents a significant breakthrough, offering a transformative pathway for advancing lead-free perovskite crystallization and expanding their potential applications.