Thermal effects on CH3NH3PbI3 perovskite from Ab initio molecular dynamics simulations

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Abstract

We present a molecular dynamics simulation study of CH3NH3PbI3 based on forces calculated from density functional theory. The simulations were performed on model systems having 8 and 27 unit cells, and for a total simulation time of 40 ps in each case. Analysis of the finite size effects, in particular the mobility of the organic component, suggests that the smaller system is over-correlated through the long-range electrostatic interaction. In the larger system, this finite size artifact is relaxed, producing a more reliable description of the anisotropic rotational behavior of the methylammonium molecules. The thermal effects on the optical properties of the system were also analyzed. The HOMO-LUMO energy gap fluctuates around its central value with a standard deviation of approximately 0.1 eV. The projected density of states consistently place the Fermi level on the p orbitals of the I atoms and the lowest virtual state on the p orbitals of the Pb atoms throughout the whole simulation trajectory.

Original languageEnglish
Pages (from-to)8991-8997
Number of pages7
JournalJournal of Physical Chemistry C
Volume119
Issue number17
DOIs
Publication statusPublished - 30 Apr 2015

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ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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