Advanced

Hot electron and hole dynamics in thiol-capped CdSe quantum dots revealed by 2D electronic spectroscopy

Lenngren, Nils LU ; Abdellah, Mohamed A. LU ; Zheng, Kaibo LU ; Al-Marri, Mohammed J.; Zigmantas, Donatas LU ; Zidek, Karel LU and Pullerits, Tõnu LU (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.

(Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
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
  • 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
2017-10-01 05:30:02
@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},
  volume       = {18},
  year         = {2016},
}