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Portrait of Tönu Pullerits; Photo: Kennet Ruona

Tönu Pullerits

Professor

Portrait of Tönu Pullerits; Photo: Kennet Ruona

Excited States and Their Dynamics in CdSe Quantum Dots Studied by Two-Color 2D Spectroscopy

Author

  • Zhengjun Wang
  • Nils Lenngren
  • Edoardo Amarotti
  • Albin Hedse
  • Karel Žídek
  • Kaibo Zheng
  • Donatas Zigmantas
  • Tõnu Pullerits

Summary, in English

Quantum dots (QDs) form a promising family of nanomaterials for various applications in optoelectronics. Understanding the details of the excited-state dynamics in QDs is vital for optimizing their function. We apply two-color 2D electronic spectroscopy to investigate CdSe QDs at 77 K within a broad spectral range. Analysis of the electronic dynamics during the population time allows us to identify the details of the excitation pathways. The initially excited high-energy electrons relax with the time constant of 100 fs. Simultaneously, the states at the band edge rise within 700 fs. Remarkably, the excited-state absorption is rising with a very similar time constant of 700 fs. This makes us reconsider the earlier interpretation of the excited-state absorption as the signature of a long-lived trap state. Instead, we propose that this signal originates from the excitation of the electrons that have arrived in the conduction-band edge.

Department/s

  • eSSENCE: The e-Science Collaboration
  • NanoLund: Center for Nanoscience
  • Chemical Physics

Publishing year

2022-02-10

Language

English

Pages

1266-1271

Publication/Series

Journal of Physical Chemistry Letters

Volume

13

Issue

5

Document type

Journal article

Publisher

The American Chemical Society (ACS)

Topic

  • Physical Chemistry
  • Nano Technology
  • Other Physics Topics

Status

Published

ISBN/ISSN/Other

  • ISSN: 1948-7185