Drastic difference between hole and electron injection through the gradient shell of CdxSeyZn1-x S1-y quantum dots

Mohamed Abdellah; Felipe Mathias Godoy Poulsen; Qiushi Zhu; Nan Zhu; Karel Zidek; Pavel Chabera; Annamaria Corti; Thorsten Hansen; Qijin Chi; Sophie E. Canton; Kaibo Zheng; Tonu Pullerits

doi:10.1039/c7nr04495j

Drastic difference between hole and electron injection through the gradient shell of Cd_xSe_yZn_1-x S_1-yquantum dots

Mohamed Abdellah, Felipe Mathias Godoy Poulsen, Qiushi Zhu, Nan Zhu, Karel Zidek, Pavel Chabera, Annamaria Corti, Thorsten Hansen, Qijin Chi, Sophie E. Canton, Kaibo Zheng, Tonu Pullerits

Department of Chemistry

5 Citations (Scopus)

60 Downloads (Pure)

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 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.

Original language	English
Journal	Nanoscale
Volume	9
Issue number	34
Pages (from-to)	12503-12508
Number of pages	6
ISSN	2040-3364
DOIs	https://doi.org/10.1039/c7nr04495j
Publication status	Published - 14 Sept 2017

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Drastic difference between hole and electron injection through the gradient shell of CdxSeyZn1-x S1-yquantum dotsFinal published version, 1.44 MBLicence: CC BY

Cite this

@article{34056237f5f748c785424af1ca3beffc,

title = "Drastic difference between hole and electron injection through the gradient shell of CdxSeyZn1-x S1-y quantum dots",

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 werecarried 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 simulatethe charge carrier tunneling through the potential barrier due to the gradient shell by numerically solving the Schr{\"o}dinger 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.",

author = "Mohamed Abdellah and Poulsen, {Felipe Mathias Godoy} and Qiushi Zhu and Nan Zhu and Karel Zidek and Pavel Chabera and Annamaria Corti and Thorsten Hansen and Qijin Chi and Canton, {Sophie E.} and Kaibo Zheng and Tonu Pullerits",

year = "2017",

month = sep,

day = "14",

doi = "10.1039/c7nr04495j",

language = "English",

volume = "9",

pages = "12503--12508",

journal = "Nanoscale",

issn = "2040-3364",

publisher = "Royal Society of Chemistry",

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TY - JOUR

T1 - Drastic difference between hole and electron injection through the gradient shell of CdxSeyZn1-x S1-y quantum dots

AU - Abdellah, Mohamed

AU - Poulsen, Felipe Mathias Godoy

AU - Zhu, Qiushi

AU - Zhu, Nan

AU - Zidek, Karel

AU - Chabera, Pavel

AU - Corti, Annamaria

AU - Hansen, Thorsten

AU - Chi, Qijin

AU - Canton, Sophie E.

AU - Zheng, Kaibo

AU - Pullerits, Tonu

PY - 2017/9/14

Y1 - 2017/9/14

N2 - 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 werecarried 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 simulatethe 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.

AB - 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 werecarried 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 simulatethe 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.

U2 - 10.1039/c7nr04495j

DO - 10.1039/c7nr04495j

M3 - Journal article

C2 - 28819669

SN - 2040-3364

VL - 9

SP - 12503

EP - 12508

JO - Nanoscale

JF - Nanoscale

IS - 34

ER -