Ultrafast Electron Injection Dynamics of Photoanodes for Water-Splitting Dye-Sensitized Photoelectrochemical Cells

John R. Swierk, Nicholas S. McCool, Coleen T. Nemes, Thomas E. Mallouk, Charles A. Schmuttenmaer

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

Efficient conversion of solar energy into useful chemical fuels is a major scientific challenge. Water-splitting dye-sensitized photoelectrochemical cells (WS-DSPECs) utilize mesoporous oxide supports sensitized with molecular dyes and catalysts to drive the water-splitting reaction. Despite a growing body of work, the overall efficiencies of WS-DSPECs remain low, in large part because of poor electron injection into the conduction band of the oxide support. In this study, we characterize the ultrafast injection dynamics of several proposed oxide supports (TiO2, TiO2/Al2O3, SnO2, SnO2/TiO2) under identical conditions using time-resolved terahertz spectroscopy. In the absence of an Al2O3 overlayer, we observe a two-step injection from the dye singlet state into nonmobile surface traps, which then relax into the oxide conduction band. We also find that, in SnO2-core/TiO2-shell configurations, electron injection into TiO2 trap states occurs rapidly, followed by trapped electrons being released into SnO2 on the hundreds of picoseconds time scale.

Original languageEnglish (US)
Pages (from-to)5940-5948
Number of pages9
JournalJournal of Physical Chemistry C
Volume120
Issue number11
DOIs
StatePublished - Mar 24 2016

Fingerprint

Photoelectrochemical cells
Electron injection
water splitting
Oxides
Coloring Agents
Dyes
dyes
injection
oxides
Water
Conduction bands
cells
conduction bands
electrons
chemical fuels
traps
Terahertz spectroscopy
solar energy
Catalyst supports
Solar energy

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Surfaces, Coatings and Films
  • Physical and Theoretical Chemistry

Cite this

Swierk, John R. ; McCool, Nicholas S. ; Nemes, Coleen T. ; Mallouk, Thomas E. ; Schmuttenmaer, Charles A. / Ultrafast Electron Injection Dynamics of Photoanodes for Water-Splitting Dye-Sensitized Photoelectrochemical Cells. In: Journal of Physical Chemistry C. 2016 ; Vol. 120, No. 11. pp. 5940-5948.
@article{08c5656e31914c4392f8aef0e2e0fe50,
title = "Ultrafast Electron Injection Dynamics of Photoanodes for Water-Splitting Dye-Sensitized Photoelectrochemical Cells",
abstract = "Efficient conversion of solar energy into useful chemical fuels is a major scientific challenge. Water-splitting dye-sensitized photoelectrochemical cells (WS-DSPECs) utilize mesoporous oxide supports sensitized with molecular dyes and catalysts to drive the water-splitting reaction. Despite a growing body of work, the overall efficiencies of WS-DSPECs remain low, in large part because of poor electron injection into the conduction band of the oxide support. In this study, we characterize the ultrafast injection dynamics of several proposed oxide supports (TiO2, TiO2/Al2O3, SnO2, SnO2/TiO2) under identical conditions using time-resolved terahertz spectroscopy. In the absence of an Al2O3 overlayer, we observe a two-step injection from the dye singlet state into nonmobile surface traps, which then relax into the oxide conduction band. We also find that, in SnO2-core/TiO2-shell configurations, electron injection into TiO2 trap states occurs rapidly, followed by trapped electrons being released into SnO2 on the hundreds of picoseconds time scale.",
author = "Swierk, {John R.} and McCool, {Nicholas S.} and Nemes, {Coleen T.} and Mallouk, {Thomas E.} and Schmuttenmaer, {Charles A.}",
year = "2016",
month = "3",
day = "24",
doi = "10.1021/acs.jpcc.6b00749",
language = "English (US)",
volume = "120",
pages = "5940--5948",
journal = "Journal of Physical Chemistry C",
issn = "1932-7447",
publisher = "American Chemical Society",
number = "11",

}

Ultrafast Electron Injection Dynamics of Photoanodes for Water-Splitting Dye-Sensitized Photoelectrochemical Cells. / Swierk, John R.; McCool, Nicholas S.; Nemes, Coleen T.; Mallouk, Thomas E.; Schmuttenmaer, Charles A.

In: Journal of Physical Chemistry C, Vol. 120, No. 11, 24.03.2016, p. 5940-5948.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Ultrafast Electron Injection Dynamics of Photoanodes for Water-Splitting Dye-Sensitized Photoelectrochemical Cells

AU - Swierk, John R.

AU - McCool, Nicholas S.

AU - Nemes, Coleen T.

AU - Mallouk, Thomas E.

AU - Schmuttenmaer, Charles A.

PY - 2016/3/24

Y1 - 2016/3/24

N2 - Efficient conversion of solar energy into useful chemical fuels is a major scientific challenge. Water-splitting dye-sensitized photoelectrochemical cells (WS-DSPECs) utilize mesoporous oxide supports sensitized with molecular dyes and catalysts to drive the water-splitting reaction. Despite a growing body of work, the overall efficiencies of WS-DSPECs remain low, in large part because of poor electron injection into the conduction band of the oxide support. In this study, we characterize the ultrafast injection dynamics of several proposed oxide supports (TiO2, TiO2/Al2O3, SnO2, SnO2/TiO2) under identical conditions using time-resolved terahertz spectroscopy. In the absence of an Al2O3 overlayer, we observe a two-step injection from the dye singlet state into nonmobile surface traps, which then relax into the oxide conduction band. We also find that, in SnO2-core/TiO2-shell configurations, electron injection into TiO2 trap states occurs rapidly, followed by trapped electrons being released into SnO2 on the hundreds of picoseconds time scale.

AB - Efficient conversion of solar energy into useful chemical fuels is a major scientific challenge. Water-splitting dye-sensitized photoelectrochemical cells (WS-DSPECs) utilize mesoporous oxide supports sensitized with molecular dyes and catalysts to drive the water-splitting reaction. Despite a growing body of work, the overall efficiencies of WS-DSPECs remain low, in large part because of poor electron injection into the conduction band of the oxide support. In this study, we characterize the ultrafast injection dynamics of several proposed oxide supports (TiO2, TiO2/Al2O3, SnO2, SnO2/TiO2) under identical conditions using time-resolved terahertz spectroscopy. In the absence of an Al2O3 overlayer, we observe a two-step injection from the dye singlet state into nonmobile surface traps, which then relax into the oxide conduction band. We also find that, in SnO2-core/TiO2-shell configurations, electron injection into TiO2 trap states occurs rapidly, followed by trapped electrons being released into SnO2 on the hundreds of picoseconds time scale.

UR - http://www.scopus.com/inward/record.url?scp=84962197478&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84962197478&partnerID=8YFLogxK

U2 - 10.1021/acs.jpcc.6b00749

DO - 10.1021/acs.jpcc.6b00749

M3 - Article

AN - SCOPUS:84962197478

VL - 120

SP - 5940

EP - 5948

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

SN - 1932-7447

IS - 11

ER -