title: Electron-phonon coupling in hybrid lead halide perovskites.
abstract: Phonon scattering limits charge-carrier mobilities and governs emission line broadening in hybrid metal halide perovskites. Establishing how charge carriers interact with phonons in these materials is therefore essential for the development of high-efficiency perovskite photovoltaics and low-cost lasers. Here we investigate the temperature dependence of emission line broadening in the four commonly studied formamidinium and methylammonium perovskites, HC(NH2)2PbI3, HC(NH2)2PbBr3, CH3NH3PbI3 and CH3NH3PbBr3, and discover that scattering from longitudinal optical phonons via the Fröhlich interaction is the dominant source of electron-phonon coupling near room temperature, with scattering off acoustic phonons negligible. We determine energies for the interacting longitudinal optical phonon modes to be 11.5 and 15.3 meV, and Fröhlich coupling constants of ∼40 and 60 meV for the lead iodide and bromide perovskites, respectively. Our findings correlate well with first-principles calculations based on many-body perturbation theory, which underlines the suitability of an electronic band-structure picture for describing charge carriers in hybrid perovskites.
authors.affiliation: Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK.
authors.forename: Adam D
authors.identifier: 0000-0003-0721-7854
authors.initials: AD
authors.lastname: Wright
authors.affiliation: Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK.
authors.forename: Carla
authors.initials: C
authors.lastname: Verdi
authors.affiliation: Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Milot
authors.affiliation: Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK.
authors.forename: Giles E
authors.identifier: 0000-0001-9600-4847
authors.initials: GE
authors.lastname: Eperon
authors.affiliation: Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Pérez-Osorio
authors.affiliation: Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK.
authors.forename: Henry J
authors.initials: HJ
authors.lastname: Snaith
authors.affiliation: Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK.
authors.forename: Feliciano
authors.initials: F
authors.lastname: Giustino
authors.affiliation: Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK.
authors.forename: Michael B
authors.initials: MB
authors.lastname: Johnston
authors.affiliation: Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK.
authors.forename: Laura M
authors.initials: LM
authors.lastname: Herz