Phase transitions in the perovskite methylammonium lead bromide, CH3ND3PbBr3

Swainson, I. P.; Hammond, Robert P.; Soullière, C.; Knop, Osvald; Massa, Werner

doi:10.1016/s0022-4596(03)00352-9

Cited by 176 publications

(271 citation statements)

References 25 publications

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“…Note also that, even though we compute the mobilities in a temperature range down to 10 K, our calculations are valid only up to about 250 K, below which the materials undergo a structural phase transition from the cubic phase studied here to a tetragonal one. 25 The calculated room temperature magnitudes of µ are summarized in Table 1 and match the experimental data for pure crystals, in particular in the case of h transport. We keep in mind that our calculations provide an upper estimate of µ, since we are solely considering the phonon contribution to the scattering.…”

supporting

confidence: 61%

Electron-phonon coupling and polaron mobility in hybrid perovskites from first-principles

Motta¹,

Sanvito²

2017

Preprint

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Density functional theory electronic structures, maximally localized Wannier funcitons and linear response theory are used to compute the electron and hole mobility, µ, of both inorganic, Cs-containing, and hybrid, CH 3 NH 3 -containing, lead bromide perovskites. When only phonon scattering is considered we find hole mobilities at room temperature in the 40-180 cm 2 V −1 s −1 range, in good agreement with experimental data for highly-ordered crystals. The electron mobility is about an order of magnitude larger, because low-energy phonons are ineffective over the Pb 6p shell. Most importantly, our parameter-free approach, finds a T −3/2 power-law temperature dependence of µ, which is a strong indication of polaronic transport in these compounds. Our work then offers an independent theoretical validation of the many hypotheses about the polaronic nature of the charge carriers in lead halide perovskites. August 16, 2017In the last few years there has been a growing effort aimed at understanding the working principles of hybrid perovskites, a novel set materials with exceptional photovoltaic properties. 1,2 Leaving aside extrinsic features such as the low cost and ease of fabrication, the key factors determining the success of these materials are threefold: 1) a useful bandgap in 1

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confidence: 61%

Electron-phonon coupling and polaron mobility in hybrid perovskites from first-principles

Motta¹,

Sanvito²

2017

Preprint

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“…It has been suggested that the motion of the perovskite cages is strongly coupled with the behavior of the organic cation 17,18,22 . It should be noted that MAPbBr 3 is structurally identical to MAPbI 3 in the cubic phase, however, MAPbBr 3 is found to have different space groups in the tetragonal and orthorhombic phases (phases II and IV in MAPbBr 3 ), and displays an additional intermediate phase, which we refer to as phase III 7,21,[23][24][25] .…”

Section: Introductionmentioning

confidence: 90%

“…MAPbBr 3 experiences four structural phase transitions between the cubic room temperature phase (phase I) and the tetragonal phase at base temperature (phase IV), with phase II being orthorhombic and phase III being previously identified as both incommensurate and tetragonal 7,[23][24][25] . The diffraction data obtained on IRIS, shown in Fig.…”

Section: A Quasielastic Neutron Scattering Using Irismolecular Motionsmentioning

confidence: 99%

Molecular orientational melting within a lead-halide octahedron framework: The order-disorder transition in CH3NH3PbBr3

et al. 2017

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Lead-halide organic-inorganic perovskites consist of an inorganic host framework with an organic molecule occupying the interstitial space. The structure and dynamics of these materials have been heavily studied recently due to interest in their exceptional photovoltaic properties. We combine inelastic neutron scattering, Raman spectroscopy, and quasielastic neutron scattering to study the temperature dependent dynamics of the molecular cation in CH3NH3PbBr3. By applying high resolution quasielastic neutron scattering, we confirm the [CH3NH3]+ ions are static in the low temperature orthorhombic phase yet become dynamic above 150 K where a series of structural transitions occur. This molecular melting is accompanied by a temporal broadening in the intra-molecular modes probed through high energy inelastic spectroscopy. Simultaneous Raman measurements, a strictly |Q|=0 probe, are suggestive that this broadening is due to local variations in the crystal field environment around the hydrogen atoms. These results confirm the strong role of hydrogen bonding and also a coupling between molecular and framework dynamics.

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“…Since ARPES is a surface-sensitive technique, the reduced symmetry at the surface may enhance non-centrosymmetric fields and the measured Rashba splitting. In the bulk, CH 3 NH 3 PbBr 3 forms an ordered orthorhombic structure of P nma symmetry at low temperature [41,42], and a disordered cubic structure with an average P m3m symmetry at room temperature [29,36,43]. Both structures are centrosymmetric after averaging over a length scale probed by x-ray and neutron diffraction, with no Rashba-type spin-splitting expected.…”

mentioning

confidence: 99%

Giant Rashba Splitting inCH3NH3PbBr3Organic-Inorganic Perovskite

et al. 2016

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As they combine decent mobilities with extremely long carrier lifetimes, organic-inorganic perovskites have opened a whole new field in optoelectronics. Measurements of their underlying electronic structure, however, are still lacking. Using angle-resolved photoelectron spectroscopy, we measure the valence band dispersion of single-crystal CH3NH3PbBr3. The dispersion of the highest energy band is extracted applying a modified leading edge method, which accounts for the particular density of states of organic-inorganic perovskites. The surface Brillouin zone is consistent with bulk-terminated surfaces both in the low-temperature orthorhombic and the high-temperature cubic phase. In the low-temperature phase, we find a ring-shaped valence band maximum with a radius of 0.043Å −1 , centered around a 0.16 eV deep local minimum in the dispersion of the valence band at the high-symmetry point. Intense circular dichroism is observed. This dispersion is the result of strong spin-orbit coupling. Spin-orbit coupling is also present in the room-temperature phase. The coupling strength is one of the largest reported so far.

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Phase transitions in the perovskite methylammonium lead bromide, CH3ND3PbBr3

Cited by 176 publications

References 25 publications

Electron-phonon coupling and polaron mobility in hybrid perovskites from first-principles

Electron-phonon coupling and polaron mobility in hybrid perovskites from first-principles

Molecular orientational melting within a lead-halide octahedron framework: The order-disorder transition in CH3NH3PbBr3

Giant Rashba Splitting inCH3NH3PbBr3Organic-Inorganic Perovskite

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