Hot electron and hole dynamics in thiol-capped CdSe quantum dots revealed by 2D electronic spectroscopy
(2016) In Physical Chemistry Chemical Physics 18(37). p.26199-26204- Abstract
Colloidal quantum dots (QDs) have attracted interest as materials for opto-electronic applications, wherein their efficient energy use requires the understanding of carrier relaxation. In QDs capped by bifunctional thiols, used to attach the QDs to a surface, the relaxation is complicated by carrier traps. Using 2D spectroscopy at 77 K, we follow excitations in thiol-capped CdSe QDs with state specificity and high time resolution. We unambiguously identify the lowest state as an optically allowed hole trap, and identify an electron trap with excited-state absorption. The presence of traps changes the initial dynamics entirely by offering a different relaxation channel. 2D electronic spectroscopy enables us to pinpoint correlations... (More)
Colloidal quantum dots (QDs) have attracted interest as materials for opto-electronic applications, wherein their efficient energy use requires the understanding of carrier relaxation. In QDs capped by bifunctional thiols, used to attach the QDs to a surface, the relaxation is complicated by carrier traps. Using 2D spectroscopy at 77 K, we follow excitations in thiol-capped CdSe QDs with state specificity and high time resolution. We unambiguously identify the lowest state as an optically allowed hole trap, and identify an electron trap with excited-state absorption. The presence of traps changes the initial dynamics entirely by offering a different relaxation channel. 2D electronic spectroscopy enables us to pinpoint correlations between states and to easily separate relaxation from different starting states. We observe the direct rapid trapping of 1S3/2, 2S3/2, and 1S1/2 holes, and several competing electron relaxation processes from the 1Pe state.
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- author
- Lenngren, Nils LU ; Abdellah, Mohamed A. LU ; Zheng, Kaibo LU ; Al-Marri, Mohammed J. ; Zigmantas, Donatas LU ; Zidek, Karel LU and Pullerits, Tõnu LU
- organization
- publishing date
- 2016
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Physical Chemistry Chemical Physics
- volume
- 18
- issue
- 37
- pages
- 6 pages
- publisher
- Royal Society of Chemistry
- external identifiers
-
- scopus:84988591380
- pmid:27722564
- wos:000385172600046
- ISSN
- 1463-9076
- DOI
- 10.1039/c6cp04190f
- language
- English
- LU publication?
- yes
- id
- bd81b39f-221b-4809-831b-63543c99b732
- date added to LUP
- 2017-02-08 11:52:44
- date last changed
- 2024-08-18 15:06:55
@article{bd81b39f-221b-4809-831b-63543c99b732, abstract = {{<p>Colloidal quantum dots (QDs) have attracted interest as materials for opto-electronic applications, wherein their efficient energy use requires the understanding of carrier relaxation. In QDs capped by bifunctional thiols, used to attach the QDs to a surface, the relaxation is complicated by carrier traps. Using 2D spectroscopy at 77 K, we follow excitations in thiol-capped CdSe QDs with state specificity and high time resolution. We unambiguously identify the lowest state as an optically allowed hole trap, and identify an electron trap with excited-state absorption. The presence of traps changes the initial dynamics entirely by offering a different relaxation channel. 2D electronic spectroscopy enables us to pinpoint correlations between states and to easily separate relaxation from different starting states. We observe the direct rapid trapping of 1S<sub>3/2</sub>, 2S<sub>3/2</sub>, and 1S<sub>1/2</sub> holes, and several competing electron relaxation processes from the 1P<sub>e</sub> state.</p>}}, author = {{Lenngren, Nils and Abdellah, Mohamed A. and Zheng, Kaibo and Al-Marri, Mohammed J. and Zigmantas, Donatas and Zidek, Karel and Pullerits, Tõnu}}, issn = {{1463-9076}}, language = {{eng}}, number = {{37}}, pages = {{26199--26204}}, publisher = {{Royal Society of Chemistry}}, series = {{Physical Chemistry Chemical Physics}}, title = {{Hot electron and hole dynamics in thiol-capped CdSe quantum dots revealed by 2D electronic spectroscopy}}, url = {{http://dx.doi.org/10.1039/c6cp04190f}}, doi = {{10.1039/c6cp04190f}}, volume = {{18}}, year = {{2016}}, }