Effect of Halide Variations on Cation Dynamics in MAPbX₃ (X = Cl, Br, and I).

ABSTRACT: We investigate the temperature-dependent dynamics of methylammonium (MA) cations in MAPbCl₃ across all crystallographic phases. We identify two distinct motions: i) a threefold rotation around the C-N axis in the orthorhombic phase, with an activation energy of 16 meV, and ii) a fourfold rotation of the entire-molecule in the tetragonal/cubic phase, with an activation energy of 60 meV. To explore the halide effects, we compare MAPbCl₃ with MAPbBr₃ and MAPbI₃, revealing a strong correlation between rotational motion and halide composition. The onset of the threefold rotation in MAPbCl₃ spans a broader temperature range than in MAPbBr₃ and MAPbI₃ due to persistent octahedral distortions and Pb─Cl bond variations. Ad

SUBMITTER: Sharma VK 

PROVIDER: S-EPMC12410906 | biostudies-literature | 2025 Sep

REPOSITORIES: biostudies-literature