Strain induced stabilization of high symmetry phase in MAPbBr3 perovskite (2503.22414v1)

Abstract: Structural phase transitions in the organic inorganic metal halide perovskites are driven via rearrangement of methylammonium cation and distortion in the PbX6 octahedra. Compositional tuning is usually incorporated for suppression of the structural phase transition in these systems with cation or anion tuning. Along with the compositional tuning, behaviour of strain present in the system can also lead to stabilization of single phase in these systems. In the present investigation, two different samples of CH3NH3PbBr3 perovskite were studied and it is observed that structural phase transition is absent for one of the sample while it is present in the other sample. The non-observance of structural phase transition and stabilization of single phase has been attributed to the perceived tensile strain in the system contrary to the compressive strain observed in the system showing structural phase transitions. This observation is further supported by theoretical calculations. Extended X-ray absorption fine structure measurements revealed distorted octahedra with varying bond lengths along planar and axial directions in both samples, along with observed increase in bond lengths in one of the sample. This stabilization of the cubic phase can enhance device performance and increase overall environmental stability, making these systems more effective for practical applications.