Effect of Iodine Octahedral Rotations on Dipole Ordering in Organic–Inorganic Hybrid Perovskite CH3NH3PbI3

Organic–inorganic hybrid perovskite MAPbI3 (MA = CH3NH3) has been rapidly growing as one of the most promising materials for future solar cells. One of the mechanisms that contribute to its high efficiency is related to the ferroelectric ordering of the MA molecules inside the inorganic framework. Here, we use first-principles calculations to explore structural distortions that can lead to the dipolar ordering of the organic molecules in the tetragonal phase, which is relevant to room-temperature applications. We find that the existence of antiphase rotation of the PbI6 octahedra has a significant impact, whereas tetragonal change of the lattice parameters is relatively unimportant for either ferroelectric or antiferroelectric configurations.