Controllable Magnetic Properties of Centimeter-Sized 2D (C4H9NH3)2CuCl4–xBrx Hybrid Perovskite Single-Crystalline Nanosheets for Spintronics Applications

Two-dimensional (2D) hybrid perovskites have been garnering increasing attention across various fields due to their rich optical, electrical, optoelectronic, and magnetic properties. Current growth techniques only offer millimeter-scale or polycrystalline perovskites, which present a major barrier to the practical large-scale applications of these materials. In this study, we successfully prepared a series of BA2CuCl4–xBrx perovskite single-crystalline nanosheets with centimeter size using a controlled cooling growth method. Characterization results suggest that the obtained single-crystalline nanosheets are of high quality and that Br is uniformly doped. Moreover, these single-crystalline nanosheets exhibit ferromagnetic ordering at low temperatures, with the Curie–Weiss temperature increasing from 14.2 to 16.5 K as Br-doping concentration increases. Our approach provides a potential solution for the scalable synthesis and application of hybrid perovskites. At the same time, this family of 2D magnetic perovskites with tunable optical properties holds great potential for future spintronics applications.