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Portrait of Reine Wallenberg. Photo: Kennet Ruona

Reine Wallenberg

Professor, Coordinator Materials Science

Portrait of Reine Wallenberg. Photo: Kennet Ruona

Multiple exciton generation in nano-crystals revisited: Consistent calculation of the yield based on pump-probe spectroscopy.

Author

  • Khadga Jung Karki
  • Fei Ma
  • Kaibo Zheng
  • Karel Zidek
  • Abdelrazek Mousa
  • Mohamed Qenawy
  • Maria Messing
  • Reine Wallenberg
  • Arkady Yartsev
  • Tönu Pullerits

Summary, in English

Multiple exciton generation (MEG) is a process in which more than one exciton is generated upon the absorption of a high energy photon, typically higher than two times the band gap, in semiconductor nanocrystals. It can be observed experimentally using time resolved spectroscopy such as the transient absorption measurements. Quantification of the MEG yield is usually done by assuming that the bi-exciton signal is twice the signal from a single exciton. Herein we show that this assumption is not always justified and may lead to significant errors in the estimated MEG yields. We develop a methodology to determine proper scaling factors to the signals from the transient absorption experiments. Using the methodology we find modest MEG yields in lead chalcogenide nanocrystals including the nanorods.

Department/s

  • Chemical Physics
  • Solid State Physics
  • Synchrotron Radiation Research
  • Centre for Analysis and Synthesis
  • NanoLund

Publishing year

2013

Language

English

Publication/Series

Scientific Reports

Volume

3

Document type

Journal article

Publisher

Nature Publishing Group

Topic

  • Atom and Molecular Physics and Optics

Status

Published

ISBN/ISSN/Other

  • ISSN: 2045-2322