Local Polar Fluctuations in Lead Halide Perovskite Crystals

Hybrid lead-halide perovskites have emerged as an excellent class of photovoltaic materials. Recent reports suggest that the organic molecular cation is responsible for local polar fluctuations that inhibit carrier recombination. We combine low-frequency Raman scattering with first-principles molecular dynamics (MD) to study the fundamental nature of these local polar fluctuations. Our observations of a strong central peak in the cubic phase of both hybrid (CH_{3}NH_{3}PbBr_{3}) and all-inorganic (CsPbBr_{3}) lead-halide perovskites show that anharmonic, local polar fluctuations are intrinsic to the general lead-halide perovskite structure, and not unique to the dipolar organic cation. MD simulations indicate…

• UD
  U.S. Department of Energy

  Awards: DE-FG02-07ER46431, DE-SC0001085, FG02-07ER46431, DE-FG02-, DE-FG02
• AE
  Archival Education and Research Institute
• WI
  Weizmann Institute of Science
• AS
  Austrian Science Fund

  Award: J3608-N20
• CN
  Conselho Nacional de Desenvolvimento Científico e Tecnológico
• OO
  Office of Science

  Award: DE-FG02-07ER46431
• NN
  National Nuclear Security Administration

  Award: DE-NA0002522
• SF
  Seventh Framework Programme

  Award: IOF-622653
• OO
  Office of Naval Research

  Awards: N00014-12-1-1033, N00014-14-1-0761, N00014-12-1, N00014
• BE
  Basic Energy Sciences

  Awards: DE-FG02-07ER46431, DE-SC0001085, DE-FG02
• CS
  Chemical Sciences, Geosciences, and Biosciences Division
• FP
  FP7 People: Marie-Curie Actions
• SN
  SLAC National Accelerator Laboratory