Mechanistic insights and optimization strategies for perovskite single-crystal thin film growth.

Perovskite materials, with their tunable band gaps, high optical absorption, and excellent carrier mobility, are key candidates for lasers, LEDs, photodetectors, and solar cells. Polycrystalline thin films dominate current applications but suffer from efficiency and stability losses largely due to grain boundaries. Perovskite single-crystal thin films (SCTFs) offer optimized carrier diffusion and reduced recombination losses, though challenges in achieving high-quality SCTFs remain. Fabrication techniques and device applications of SCTFs have been widely explored, yet the crystallization mechanisms that critically influence film quality and device performance offer significant opportunities for further investigation. This review aims to provide a comprehensive analysis of SCTF nucleation, growth dynamics, and structural optimization, highlighting the role of external factors like substrate properties and solution chemistry. By advancing the understanding of these mechanisms, we hope to guide efficient SCTF fabrication and inspire innovations in high-performance, stable perovskite-based optoelectronics.