TY - JOUR
T1 - The nature of dynamic local order in CH3NH3PbI3 and CH3NH3PbBr3
AU - Weadock, Nicholas J.
AU - Sterling, Tyler C.
AU - Vigil, Julian A.
AU - Gold-Parker, Aryeh
AU - Smith, Ian C.
AU - Ahammed, Ballal
AU - Krogstad, Matthew J.
AU - Ye, Feng
AU - Voneshen, David
AU - Gehring, Peter M.
AU - Rappe, Andrew M.
AU - Steinrück, Hans Georg
AU - Ertekin, Elif
AU - Karunadasa, Hemamala I.
AU - Reznik, Dmitry
AU - Toney, Michael F.
N1 - Publisher Copyright:
© 2023 Elsevier Inc.
PY - 2023/5/17
Y1 - 2023/5/17
N2 - Hybrid lead-halide perovskites (LHPs) are semiconductors with novel properties that are distinctively governed by structural fluctuations. Diffraction experiments sensitive to long-range order reveal a cubic structure in the device-relevant, high-temperature phase. Local probes find additional short-range order with lower symmetry that may govern structure-function relationships. However, our understanding is impeded by unresolved dimensionality, participating atoms, and dynamics of short-range order. Here, we determine the true structure of two hybrid LHPs, CH3NH3PbI3 and CH3NH3PbBr3, using a combination of single-crystal diffuse scattering, neutron inelastic spectroscopy, and molecular dynamics simulations. The remarkable collective dynamics, not observed in previous studies, consist of a network of local, two-dimensional, circular regions of dynamically tilting lead-halide octahedra (lower symmetry) that induce longer-range intermolecular CH3NH3+ correlations. The dynamic local structure may introduce transient ferroelectric or antiferroelectric domains that increase charge carrier lifetimes and strongly affect halide migration, a poorly understood degradation mechanism.
AB - Hybrid lead-halide perovskites (LHPs) are semiconductors with novel properties that are distinctively governed by structural fluctuations. Diffraction experiments sensitive to long-range order reveal a cubic structure in the device-relevant, high-temperature phase. Local probes find additional short-range order with lower symmetry that may govern structure-function relationships. However, our understanding is impeded by unresolved dimensionality, participating atoms, and dynamics of short-range order. Here, we determine the true structure of two hybrid LHPs, CH3NH3PbI3 and CH3NH3PbBr3, using a combination of single-crystal diffuse scattering, neutron inelastic spectroscopy, and molecular dynamics simulations. The remarkable collective dynamics, not observed in previous studies, consist of a network of local, two-dimensional, circular regions of dynamically tilting lead-halide octahedra (lower symmetry) that induce longer-range intermolecular CH3NH3+ correlations. The dynamic local structure may introduce transient ferroelectric or antiferroelectric domains that increase charge carrier lifetimes and strongly affect halide migration, a poorly understood degradation mechanism.
KW - diffuse scattering
KW - ion migration
KW - local structure
KW - metal halide perovskites
KW - molecular dynamics simulations
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U2 - 10.1016/j.joule.2023.03.017
DO - 10.1016/j.joule.2023.03.017
M3 - Article
AN - SCOPUS:85159083013
SN - 2542-4351
VL - 7
SP - 1051
EP - 1066
JO - Joule
JF - Joule
IS - 5
ER -