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Drastic difference between hole and electron injection through the gradient shell of Cd: XSeyZn1- xS1- y quantum dots

Abdellah, Mohamed LU ; Poulsen, Felipe; Zhu, Qiushi LU ; Zhu, Nan; Žídek, Karel; Chábera, Pavel LU ; Corti, Annamaria; Hansen, Thorsten LU ; Chi, Qijin and Canton, Sophie E. LU , et al. (2017) In Nanoscale 9(34). p.12503-12508
Abstract

Ultrafast fluorescence spectroscopy was used to investigate the hole injection in CdxSeyZn1-xS1-y gradient core-shell quantum dot (CSQD) sensitized p-type NiO photocathodes. A series of CSQDs with a wide range of shell thicknesses was studied. Complementary photoelectrochemical cell measurements were carried out to confirm that the hole injection from the active core through the gradient shell to NiO takes place. The hole injection from the valence band of the QDs to NiO depends much less on the shell thickness when compared to the corresponding electron injection to n-type semiconductor (ZnO). We simulate the charge carrier tunneling through the potential barrier due to the gradient shell by... (More)

Ultrafast fluorescence spectroscopy was used to investigate the hole injection in CdxSeyZn1-xS1-y gradient core-shell quantum dot (CSQD) sensitized p-type NiO photocathodes. A series of CSQDs with a wide range of shell thicknesses was studied. Complementary photoelectrochemical cell measurements were carried out to confirm that the hole injection from the active core through the gradient shell to NiO takes place. The hole injection from the valence band of the QDs to NiO depends much less on the shell thickness when compared to the corresponding electron injection to n-type semiconductor (ZnO). We simulate the charge carrier tunneling through the potential barrier due to the gradient shell by numerically solving the Schrödinger equation. The details of the band alignment determining the potential barrier are obtained from X-ray spectroscopy measurements. The observed drastic differences between the hole and electron injection are consistent with a model where the hole effective mass decreases, while the gradient shell thickness increases.

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publication status
published
subject
in
Nanoscale
volume
9
issue
34
pages
6 pages
publisher
Royal Society of Chemistry
external identifiers
  • scopus:85028699658
  • wos:000409215300033
ISSN
2040-3364
DOI
10.1039/c7nr04495j
language
English
LU publication?
yes
id
135ce7aa-7756-40db-95aa-0c16c3d4a944
date added to LUP
2017-09-26 09:48:54
date last changed
2018-01-16 13:26:34
@article{135ce7aa-7756-40db-95aa-0c16c3d4a944,
  abstract     = {<p>Ultrafast fluorescence spectroscopy was used to investigate the hole injection in Cd<sub>x</sub>Se<sub>y</sub>Zn<sub>1-x</sub>S<sub>1-y</sub> gradient core-shell quantum dot (CSQD) sensitized p-type NiO photocathodes. A series of CSQDs with a wide range of shell thicknesses was studied. Complementary photoelectrochemical cell measurements were carried out to confirm that the hole injection from the active core through the gradient shell to NiO takes place. The hole injection from the valence band of the QDs to NiO depends much less on the shell thickness when compared to the corresponding electron injection to n-type semiconductor (ZnO). We simulate the charge carrier tunneling through the potential barrier due to the gradient shell by numerically solving the Schrödinger equation. The details of the band alignment determining the potential barrier are obtained from X-ray spectroscopy measurements. The observed drastic differences between the hole and electron injection are consistent with a model where the hole effective mass decreases, while the gradient shell thickness increases.</p>},
  author       = {Abdellah, Mohamed and Poulsen, Felipe and Zhu, Qiushi and Zhu, Nan and Žídek, Karel and Chábera, Pavel and Corti, Annamaria and Hansen, Thorsten and Chi, Qijin and Canton, Sophie E. and Zheng, Kaibo and Pullerits, Tõnu},
  issn         = {2040-3364},
  language     = {eng},
  month        = {09},
  number       = {34},
  pages        = {12503--12508},
  publisher    = {Royal Society of Chemistry},
  series       = {Nanoscale},
  title        = {Drastic difference between hole and electron injection through the gradient shell of Cd<sub>: X</sub>Se<sub>y</sub>Zn<sub>1- x</sub>S<sub>1- y</sub> quantum dots},
  url          = {http://dx.doi.org/10.1039/c7nr04495j},
  volume       = {9},
  year         = {2017},
}