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

Wang, Zhengjun LU ; Lenngren, Nils LU ; Amarotti, Edoardo LU ; Hedse, Albin LU ; Žídek, Karel LU ; Zheng, Kaibo LU ; Zigmantas, Donatas LU orcid and Pullerits, Tõnu LU (2022) In Journal of Physical Chemistry Letters 13(5). p.1266-1271
Abstract

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... (More)

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.

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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Physical Chemistry Letters
volume
13
issue
5
pages
6 pages
publisher
The American Chemical Society (ACS)
external identifiers
  • scopus:85124085591
  • pmid:35089715
ISSN
1948-7185
DOI
10.1021/acs.jpclett.1c04110
language
English
LU publication?
yes
additional info
Publisher Copyright: ©
id
4f17cf94-f491-422b-a259-0942f100c8e4
date added to LUP
2022-03-21 11:25:58
date last changed
2024-06-19 09:26:25
@article{4f17cf94-f491-422b-a259-0942f100c8e4,
  abstract     = {{<p>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. </p>}},
  author       = {{Wang, Zhengjun and Lenngren, Nils and Amarotti, Edoardo and Hedse, Albin and Žídek, Karel and Zheng, Kaibo and Zigmantas, Donatas and Pullerits, Tõnu}},
  issn         = {{1948-7185}},
  language     = {{eng}},
  month        = {{02}},
  number       = {{5}},
  pages        = {{1266--1271}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{Journal of Physical Chemistry Letters}},
  title        = {{Excited States and Their Dynamics in CdSe Quantum Dots Studied by Two-Color 2D Spectroscopy}},
  url          = {{http://dx.doi.org/10.1021/acs.jpclett.1c04110}},
  doi          = {{10.1021/acs.jpclett.1c04110}},
  volume       = {{13}},
  year         = {{2022}},
}