Mechanical pressing method for making high-quality perovskite single crystals

Halide perovskites show excellent photovoltaic properties[1?4]. However, the preparation of high-quality perovskite crystals remains a great challenge, which limits their applications.Perovskite materials applied to photodetectors mainly include polycrystalline thin films and single crystals. Traditional solution methods are used to prepare polycrystalline thin films, and the films are full of defects such as voids and grain boundaries[5?7]. Compared to polycrystalline thin films,perovskite single crystals possess high crystallinity and low defect density[8?10].