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Sahar Pakdel

Exciton diffusion in two-dimensional metal-halide perovskites

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  • Michael Seitz, Universidad Autónoma de Madrid
  • ,
  • Alvaro J. Magdaleno, Universidad Autónoma de Madrid
  • ,
  • Nerea Alcázar-Cano, Universidad Autónoma de Madrid
  • ,
  • Marc Meléndez, Universidad Autónoma de Madrid
  • ,
  • Tim J. Lubbers, Universidad Autónoma de Madrid
  • ,
  • Sanne W. Walraven, Universidad Autónoma de Madrid
  • ,
  • Sahar Pakdel
  • Elsa Prada, Universidad Autónoma de Madrid
  • ,
  • Rafael Delgado-Buscalioni, Universidad Autónoma de Madrid
  • ,
  • Ferry Prins, Universidad Autónoma de Madrid

Two-dimensional layered perovskites are attracting increasing attention as more robust analogues to the conventional three-dimensional metal-halide perovskites for both light harvesting and light emitting applications. However, the impact of the reduced dimensionality on the optoelectronic properties remains unclear, particularly regarding the spatial dynamics of the excitonic excited state within the two-dimensional plane. Here, we present direct measurements of exciton transport in single-crystalline layered perovskites. Using transient photoluminescence microscopy, we show that excitons undergo an initial fast diffusion through the crystalline plane, followed by a slower subdiffusive regime as excitons get trapped. Interestingly, the early intrinsic diffusivity depends sensitively on the choice of organic spacer. A clear correlation between lattice stiffness and diffusivity is found, suggesting exciton–phonon interactions to be dominant in the spatial dynamics of the excitons in perovskites, consistent with the formation of exciton–polarons. Our findings provide a clear design strategy to optimize exciton transport in these systems.

TidsskriftNature Communications
StatusUdgivet - 2020

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