Temporally-decoherent and spatially-coherent vibrations in metal halide perovskite

Abstract

The long carrier lifetime and defect tolerance in metal halide perovskites (MHPs) are major contributors to the superb performance of MHP optoelectronic devices. Large polarons were reported to be responsible for the long carrier lifetime. Yet microscopic mechanisms of the large polaron formation including the so-called phonon melting, are still under debate. Here, time-of-flight (TOF) inelastic neutron scattering (INS) experiments and first-principles density-functional theory (DFT) calculations were employed to investigate the lattice vibrations (or phonon dynamics) in methylammonium lead iodide ($\mathrm{MAPb}{\mathrm{I}}_3$), a prototypical example of MHPs. Our findings are that optical phonons lose temporal coherence gradually with increasing temperature which vanishes at the orthorhombic-to-tetragonal structural phase transition. Surprisingly, however, we found that the spatial coherence is still retained throughout the decoherence process. We argue that the temporally decoherent and spatially coherent vibrations contribute to the formation of large polarons in this metal halide perovskite.

References in corpus (20)

• Van der Waals Density Functional for General Geometries
• Van der Waals density functionals applied to solids
• A Higher-Accuracy van der Waals Density Functional
• Direct Measurement of the Exciton Binding Energy and Effective Masses for Charge carriers in an Organic-Inorganic Tri-halide Perovskite
• Efficient implementation of a van der Waals density functional: Application to double-wall carbon nanotubes
• Local polar fluctuations in lead halide perovskite crystals
• Phonon-glass electron-crystal thermoelectric clathrates: Experiments and theory
• Direct Observation of Dynamic Symmetry Breaking above Room Temperature in Methylammonium Lead Iodide Perovskite
• Real-Time Observation of Exciton-Phonon Coupling Dynamics in Self-Assembled Hybrid Perovskite Quantum Wells
• Rotational Dynamics of Organic Cations in CH3NH3PbI3 Perovskite
• Slow cooling of hot polarons in halide perovskite solar cells
• Stable biexcitons in two-dimensional metal-halide perovskites with strong dynamic lattice disorder
• From soft harmonic phonons to fast relaxational dynamics in CH${}_3$NH${}_3$PbBr${}_3$
• Acoustic Phonon Lifetimes Limit Thermal Transport in Methylammonium Lead Iodide
• Lattice Thermal Conductivity of Organic-Inorganic Hybrid Perovskite CH3NH3PbI3
• Direct evidence of weakly dispersed and strongly anharmonic optical phonons in hybrid perovskites
• Lattice dynamics and the nature of structural transitions in organolead halide perovskites
• Quantum oscillations of nitrogen atoms in uranium nitride
• Influence of Chloride Substitution on the Rotational Dynamics of Methylammonium in MAPbI${}_{3-x}$Cl${}_x$ Perovskites
• Decoupled molecular and inorganic framework dynamics in CH${}_3$NH${}_3$PbCl${}_3$

Cited by in corpus (1)

• Pseudospin-phonon pretransitional dynamics in lead halide hybrid perovskites