Influence of crystallographic planes on mechanical properties and photodetection characteristics in ambient-grown MAPbI3 perovskite single crystals

Hybrid perovskite single crystals have recently drawn significant interest for their innovative potential in diverse optoelectronic technologies. However, their mechanical properties have remained relatively underexplored, even though it plays a crucial role in determining device durability and long-term performance. In this work, single crystals of MAPbI₃ perovskite were grown using a seeding-induced Inverse Temperature Crystallization (ITC) method. Since, in a single crystal the atomic arrangements can vary along different crystallographic directions, we investigated the mechanical properties of the (100) and (112) crystallographic planes using Vicker's microhardness technique. The results revealed mechanical anisotropy, with the (112) plane exhibiting higher hardness value than (100) plane. These findings were further analyzed using Meyer's law, the Hays and Kendall (HK) law, and the Elastic Plastic Deformation (EPD) law. Additionally, photodetection performance of both planes was evaluated across a wide range of visible light. The (112) plane demonstrated superior performance, with significantly higher photocurrent values, 1.5 times increase in ON/OFF ratio, and improved response and recovery times. These findings highlight the superior mechanical and electrical properties of MAPbI₃ perovskite crystals along (112) crystallographic orientation, making it the preferred choice for device applications.