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Multiexciton absorption cross sections of CdSe@CdS nanorods studied using pump–repump–probe spectroscopy

Kumar, Krishan ; Uhlig, Jens LU orcid ; Baruah, Raktim ; Yadav, Shivani and Wächtler, Maria (2026) In Nanoscale
Abstract

While the multiexciton dynamics in semiconductor nanocrystals is widely explored, to determine the absorption cross sections for multiexcitons of varying order is still a challenge. In this study, we performed pump–repump–probe transient absorption (ppp-TA) spectroscopic measurements on CdSe@CdS nanorods to gain insights into the absorption cross sections for multiexcitons. By tuning the pump–repump delay time and repump intensity, we were able to generate and reexcite various transiently living multiexcitonic species distributions. By modelling the ppp-TA data using a Markov Chain Monte Carlo target analysis method, the spectral shape and lifetime of higher order excitons (up to tri-excitons), and absorption cross section parameters... (More)

While the multiexciton dynamics in semiconductor nanocrystals is widely explored, to determine the absorption cross sections for multiexcitons of varying order is still a challenge. In this study, we performed pump–repump–probe transient absorption (ppp-TA) spectroscopic measurements on CdSe@CdS nanorods to gain insights into the absorption cross sections for multiexcitons. By tuning the pump–repump delay time and repump intensity, we were able to generate and reexcite various transiently living multiexcitonic species distributions. By modelling the ppp-TA data using a Markov Chain Monte Carlo target analysis method, the spectral shape and lifetime of higher order excitons (up to tri-excitons), and absorption cross section parameters for different multiexcitonic species are accessible. We find that at the repump wavelength 400 nm used in this study the absorption cross sections of the exciton and multiexciton species are smaller compared to the ground state species. The determined values indicate that the biexciton absorption cross section at 400 nm is slightly larger than the cross section for the monoexciton and triexciton determined in our study.

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organization
publishing date
type
Contribution to journal
publication status
epub
subject
in
Nanoscale
publisher
Royal Society of Chemistry
external identifiers
  • scopus:105030166454
  • pmid:41693523
ISSN
2040-3364
DOI
10.1039/d5nr04981d
language
English
LU publication?
yes
id
2866a599-11ff-4ac2-b529-6b5f71e9ee73
date added to LUP
2026-03-02 12:57:29
date last changed
2026-05-26 01:32:09
@article{2866a599-11ff-4ac2-b529-6b5f71e9ee73,
  abstract     = {{<p>While the multiexciton dynamics in semiconductor nanocrystals is widely explored, to determine the absorption cross sections for multiexcitons of varying order is still a challenge. In this study, we performed pump–repump–probe transient absorption (ppp-TA) spectroscopic measurements on CdSe@CdS nanorods to gain insights into the absorption cross sections for multiexcitons. By tuning the pump–repump delay time and repump intensity, we were able to generate and reexcite various transiently living multiexcitonic species distributions. By modelling the ppp-TA data using a Markov Chain Monte Carlo target analysis method, the spectral shape and lifetime of higher order excitons (up to tri-excitons), and absorption cross section parameters for different multiexcitonic species are accessible. We find that at the repump wavelength 400 nm used in this study the absorption cross sections of the exciton and multiexciton species are smaller compared to the ground state species. The determined values indicate that the biexciton absorption cross section at 400 nm is slightly larger than the cross section for the monoexciton and triexciton determined in our study.</p>}},
  author       = {{Kumar, Krishan and Uhlig, Jens and Baruah, Raktim and Yadav, Shivani and Wächtler, Maria}},
  issn         = {{2040-3364}},
  language     = {{eng}},
  publisher    = {{Royal Society of Chemistry}},
  series       = {{Nanoscale}},
  title        = {{Multiexciton absorption cross sections of CdSe@CdS nanorods studied using pump–repump–probe spectroscopy}},
  url          = {{http://dx.doi.org/10.1039/d5nr04981d}},
  doi          = {{10.1039/d5nr04981d}},
  year         = {{2026}},
}