Bidirectional Halide Ion Exchange in Paired Lead Halide Perovskite Films with Thermal Activation



MAPbBr3 and MAPbI3 films cast onto glass slides and physically paired together undergo halide exchange to form mixed halide films. The change in halide composition in these two ∼130 nm thick films occurs concurrently with Br− diffusing toward the MAPbI3 film and I− diffusing toward the MAPbBr3 film. The diffusion of these halide species, which is tracked through changes in the absorption, offers a direct measurement of thermally activated halide diffusion in perovskite films. The increase in the rate constant of halide diffusion with increasing temperature (from 8.3 × 10−6 s−1 at 23 °C to 3.7 × 10−4 s−1 at 140 °C) follows an Arrhenius relationship with activation energy of 51 kJ/mol. The thermally activated halide exchange shows the challenges of employing layers of different metal halide perovskites in stable tandem solar cells.


Attribute NameValues
  • R. Scheidt

  • B. Seger

  • P. Kamat

  • Tor Elmelund

Journal or Work Title
  • ACS Energy Letter

  • 4

First Page
  • 1961

Last Page
  • 1969

  • 2380-8195

Publication Date
  • 2019-07

  • Titan TEM

  • SEM

  • American Chemical Society

Date Created
  • 2019-08-08

  • English

Departments and Units
Record Visibility Public
Content License
  • All rights reserved

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