Direct Observation of Dynamic Symmetry Breaking above Room Temperature in Methylammonium Lead Iodide Perovskite

Alexander N. Beecher, Octavi Escala Semonin, Jonathan M. Skelton, Jarvist M. Frost, Maxwell W. Terban, Haowei Zhai, Ahmet Alatas, Jonathan S. Owen, Aron Walsh, Simon J. L. Billinge
  • ACS Energy Letters, September 2016, American Chemical Society (ACS)
  • DOI: 10.1021/acsenergylett.6b00381

Local atomic displacements help a solar cell material do its magic

What is it about?

Converting sunlight into electricity involves capturing the light photons, using the energy to split apart positive and negative electrical charges, and then separating them. This is a delicate multi-dimensional dance that is done exceptionally well by the recently discovered Methylammonium Lead Iodide (MAPI) material, but how does it do it? This paper reveals a secret that hints at this, with the discovery of local atomic displacements that fluctuate very slowly, leaving in their wake a pattern of electric dipoles that the photoexcited charges move through.

Why is it important?

Understanding how MAPI does its photovoltaic magic is an important first step to finding even better materials for solar cells. The new insights from this work help us to understand how details of the inorganic PbI framework interact with the exotic methylammonium component in a coordinated way to do this and will help us to find other related materials, for example, non-lead containing ones, for improved applications.

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The following have contributed to this page: Maxwell Terban and Simon Billinge