Lattice dynamics and the nature of structural transitions in organolead halide perovskites

Abstract

Organolead halide perovskites are a family of hybrid organic-inorganic compounds whose remarkable optoelectronic properties have been under intensive scrutiny in recent years. Here we use inelastic X-ray scattering to study low-energy lattice excitations in single crystals of methylammonium lead iodide and bromide perovskites. Our findings confirm the displacive nature of the cubic-to-tetragonal phase transition, which is further shown, using neutron and x-ray diffraction, to be close to a tricritical point. Lastly, we detect quasistatic symmetry-breaking nanodomains persisting well into the high-temperature cubic phase, possibly stabilized by local defects. These findings reveal key structural properties of these materials, and also bear important implications for carrier dynamics across an extended temperature range relevant for photovoltaic applications.

arXiv commentAccepted to Physical Review B

References in corpus (2)

• Lattice dynamics and vibrational spectra of the orthorhombic, tetragonal and cubic phases of methylammonium lead iodide
• Dynamic disorder, phonon lifetimes, and the assignment of modes to the vibrational spectra of methylammonium lead halide perovskites

Cited by in corpus (13)

• Elastic softness of hybrid lead halide perovskites
• Phonon anharmonicity, lifetimes and thermal transport in CH${}_3$NH${}_3$PbI${}_3$ from many-body perturbation theory
• Acoustic Phonon Lifetimes Limit Thermal Transport in Methylammonium Lead Iodide
• Direct evidence of weakly dispersed and strongly anharmonic optical phonons in hybrid perovskites
• Dynamic Nanodomains Dictate Macroscopic Properties in Lead Halide Perovskites
• Molecular orientational melting within a lead-halide octahedra framework - the order-disorder transition in CH3NH3PbBr3
• The Effect of Ionic Composition on Acoustic Phonon Speeds in Hybrid Perovskites from Brillouin Spectroscopy and Density Functional Theory
• Pseudospin-phonon pretransitional dynamics in lead halide hybrid perovskites
• On the question of dynamic domains and critical scattering in cubic methylammonium lead triiodide
• Lifetime-shortened acoustic phonons and static order at the Brillouin zone boundary in the organic-inorganic perovskite CH${}_3$NH${}_3$PbCl${}_3$
• Temporally-decoherent and spatially-coherent vibrations in metal halide perovskite
• Opto-thermal transport engineering in hybrid organic-inorganic lead halide perovskites metasurfaces
• Review: Solid-state physics of halide perovskites