Mechanical Properties of Single Crystal Organic–Inorganic Hybrid Perovskite MAPbX₃ (MA = CH₃NH₃, X = Cl, Br, I)

Mechanical properties are among the crucial parameters for multilayer hybrid perovskite-based devices. Here, the mechanical properties of the high-quality single-crystalline MAPbX₃ (MA = CH₃NH₃, X = Cl, Br, I), including the hardness (H) and Young’s modulus (E), are systematically studied using the three-dimensional nanoindentation (3D nanoindentation) method. In the sequence of Cl, Br, and I, the hardness and Young’s modulus of MAPbX₃ decrease gradually. The hardness of MAPbX₃ ranges from 0.31 to 0.57 GPa, and Young’s modulus values are less than 30 GPa. The low hardness and Young’s modulus are attributed to the weak lattice framework composed of Pb-X and the weak hydrogen bond between CH₃NH₃⁺ and the octahedron. The relationship between the hardness and Young’s modulus of MAPbX₃ is also described. Generally, this work provides the favorable parameters required to further support the design and modification of investigations regarding perovskite-based devices.