The browser you are using is not supported by this website. All versions of Internet Explorer are no longer supported, either by us or Microsoft (read more here: https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Please use a modern browser to fully experience our website, such as the newest versions of Edge, Chrome, Firefox or Safari etc.

Aboma Mendasa, MSc, PhD. Photo.

Aboma Merdasa

Researcher

Aboma Mendasa, MSc, PhD. Photo.

"Supertrap" at Work: Extremely Efficient Nonradiative Recombination Channels in MAPbI3 Perovskites Revealed by Luminescence Super-Resolution Imaging and Spectroscopy

Author

  • Aboma Merdasa
  • Yuxi Tian
  • Rafael Camacho
  • Alexander Dobrovolsky
  • Elke Debroye
  • Eva L. Unger
  • Johan Hofkens
  • Villy Sundström
  • Ivan G. Scheblykin

Summary, in English

Organo-metal halide perovskites are some of the most promising materials for the new generation of low-cost photovoltaic and light-emitting devices. Their solution processability is a beneficial trait, although it leads to a spatial inhomogeneity of perovskite films with a variation of the trap state density at the nanoscale. Comprehending their properties using traditional spectroscopy therefore becomes difficult, calling for a combination with microscopy in order to see beyond the ensemble-averaged response. We studied photoluminescence (PL) blinking of micrometer-sized individual methylammonium lead iodide (MAPbI3) perovskite polycrystals, as well as monocrystalline microrods up to 10 μm long. We correlated their PL dynamics with structure employing scanning electron and optical super-resolution microscopy. Combining super-resolution localization imaging and super-resolution optical fluctuation imaging (SOFI), we could detect and quantify preferential emitting regions in polycrystals exhibiting different types of blinking. We propose that blinking in MAPbI3 occurs by the activation/passivation of a "supertrap" which presumably is a donor-acceptor pair able to trap both electrons and holes. As such, nonradiative recombination via supertraps, in spite being present at a rather low concentrations (1012-1015 cm-3), is much more efficient than via all other defect states present in the material at higher concentrations (1016-1018 cm-3). We speculate that activation/deactivation of a supertrap occurs by its temporary dissociation into free donor and acceptor impurities. We found that supertraps are most efficient in structurally homogeneous and large MAPbI3 crystals where carrier diffusion is efficient, which may therefore pose limitations on the efficiency of perovskite-based devices.

Department/s

  • Chemical Physics
  • NanoLund: Centre for Nanoscience

Publishing year

2017-06-27

Language

English

Pages

5391-5404

Publication/Series

ACS Nano

Volume

11

Issue

6

Document type

Journal article

Publisher

The American Chemical Society (ACS)

Topic

  • Condensed Matter Physics
  • Physical Chemistry

Keywords

  • blinking
  • donor-acceptor pair
  • nonradiative recombination
  • perovskites
  • photoluminescence
  • super-resolution microscopy
  • traps

Status

Published

ISBN/ISSN/Other

  • ISSN: 1936-0851