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Steering ultrafast processes in artificial photosynthesis
Dr. ir. Annemarie Huijser
Expertise
http://photon-science.desy.de
Ultrafast light-matter interactions
PhD research on dye-sensitized solar cells
porphyrin molecule
exciton diffusion length
2004-2008, TU Delft
Postdoctoral research2008-2011, Lund University, Sweden
Development of new research line on ultrafast photochemistry of melanins
Postdoctoral research
various excited state proton transfer channels
Development of new research line on ultrafast photochemistry of melanins
2008-2011, Lund University, Sweden
Artificial photosynthesis
Artificial photosynthesis
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H2 evolving catalystO2 evolving catalyst
Artificial photosynthesis
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H2 evolving catalystO2 evolving catalyst Fujishima, A.; Honda, K. Nature 1972, 238, 37.
Artificial photosynthesis
Y. Tachibana et al, Nature Photonics, 6 (2012) 511.M.G. Walter et al, Chem. Rev. 11, 110 (2010) 6446.
H2 evolving catalystO2 evolving catalyst
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Artificial photosynthesisz-scheme
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Y. Tachibana et al, Nature Photonics, 6 (2012) 511.M.G. Walter et al, Chem. Rev. 11, 110 (2010) 6446.
H2 evolving catalystO2 evolving catalyst
Challengesz-scheme
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Y. Tachibana et al, Nature Photonics, 6 (2012) 511.M.G. Walter et al, Chem. Rev. 11, 110 (2010) 6446.
H2 evolving catalystO2 evolving catalyst
Directionality of electron transfer Long-lived charge separation Multiple electrons (Photo)chemical stability Control of interface structure Efficient catalysts Device integration
Approaches
www.its.caltech.edu
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Research line
www.its.caltech.edu
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Research line
Steering ultrafast photophysical processes in artificial photosynthesis by tuning the
3D structure
environment
directionality of e- transfer long-lived charge separation
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Techniques
Femtosecond pump-probe
Ultrafast fluorescence (streak camera, single photon counting)
Ultrafast x-ray absorption (at synchrotron)
Tandem photoelectrochemical cell
H2
e-
O2
semiconductor
T.J. Meyer et al, PNAS, 110 (2013) 20008.
Design strategy H2 evolving photocatalyst
RuRubridgingligand
peripheral ligands
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H+ reduction at ~µs time scale
charge storage reservoir
PtPt
M. Frey, ChemBioChem, 3 (2002) 153.P. Hamm et al, Eur. J. Inorg. Chem. 2012 (2012) 59.
S. Rau et al, Dalton Trans. 915 (2007) 915.J. Popp et al, Chem. Eur. J., 15 (2009) 7678.
key parameters charge separation till s time scale population peripheral ↔ bridging ligands evolution in time directionality electron transfer to catalytic site
Impact structure bridging ligand
long-lived charge separation
photoluminescene lifetime 623 ±5 ns
fast recombination
ground state bleach
ground state bleach
wavelength (nm)
wavelenght (nm)
ΔOD
ΔOD
Q. Pan et al, J. Phys. Chem. C. 118 (2014) 20799.
Impact structure bridging ligand
long-lived charge separation
photoluminescene lifetime 623 ±5 ns
fast recombination
ground state bleach
ground state bleach
wavelength (nm)
wavelength (nm)
ΔOD
ΔOD
Q. Pan et al, J. Phys. Chem. C. 118 (2014) 20799.
State-of-the art photocatalyst
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wavelength (nm)
H2 turn over number 99
time
ΔOD
wavelength (nm)
Q. Pan et al, manuscript in preparation. T. Kowacs et al, Farad. Disc. 185 (2015) 143.
State-of-the art photocatalyst
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wavelength (nm)
H2 turn over number 120
time
ΔOD
wavelength (nm)
Q. Pan et al, J. Phys. Chem. C. 118 (2014) 20799. T. Kowacs et al, Farad. Disc. 185 (2015) 143.
State-of-the art photocatalyst
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H2 turn over number 120
475 nm (ground state bleach)
370 nm
420 nm
ΔOD
time (ps)
Q. Pan et al, J. Phys. Chem. C. 118 (2014) 20799. T. Kowacs et al, Farad. Disc. 185 (2015) 143.
Photophysical model
ground state
singlet excited state
relaxed peripheral ligand-basedtriplet excited state bridging
ligand-basedtriplet excited
state
21%,<100 fs79%,<100 fs 32 ps
Pd
~400 ns ~100 ns
hot peripheral ligand-basedtriplet excited state 9 ps
Q. Pan et al, J. Phys. Chem. C. 118 (2014) 20799.
Photophysical model
ground state
singlet excited state
relaxed peripheral ligand-basedtriplet excited state bridging
ligand-basedtriplet excited
state
79%,<100 fs 32 ps
Pd
~400 ns ~100 ns
hot peripheral ligand-basedtriplet excited state 9 ps x
21%,<100 fs
Q. Pan et al, J. Phys. Chem. C. 118 (2014) 20799.
Photophysical model
ground state
singlet excited state
relaxed peripheral ligand-basedtriplet excited state bridging
ligand-basedtriplet excited
state
79%,<100 fs 32 ps
Pt
~400 ns ~100 ns
hot peripheral ligand-basedtriplet excited state 9 ps x time-resolved x-ray
absorption: 100 ps
21%,<100 fs
J. Uhlig et al, manuscript in preparation.
Photophysical model
ground state
singlet excited state
relaxed peripheral ligand-basedtriplet excited state bridging
ligand-basedtriplet excited
state
79%,<100 fs 32 ps
Pt
~400 ns ~100 ns
hot peripheral ligand-basedtriplet excited state 9 ps x time-resolved x-ray
absorption: 100 ps
21%,<100 fs
J. Uhlig et al, manuscript in preparation.
Time-resolved x-ray absorption spectroscopy
J. Uhlig et al, manuscript in preparation.
Energy (keV)
Diff
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nce
(%
)
Functionalizing peripheral ligands
EtOOC
EtOOC
H2 turn over number 720
T. Kowacs et al, submitted manuscript.Q. Pan et al, submitted manuscript.
Functionalizing peripheral ligands
EtOOC
EtOOC
H2 turn over number 720
wavelength (nm)
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T. Kowacs et al, submitted manuscript.Q. Pan et al, submitted manuscript.
time
Inversion directionality electron transfer
EtOOC
EtOOC
H2 turn over number 720
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T. Kowacs et al, submitted manuscript.Q. Pan et al, submitted manuscript.
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H2 turn over number 99
DFT calculations spin densities lowest triplet excited state
H2 turn over number 720 H2 turn over number 99
peripheral ligandsbridging ligand
T. Kowacs et al, submitted manuscript.Q. Pan et al, submitted manuscript.
How to understand the high H2 turn over number?
ground state
singlet excited state
peripheral ligand-basedtriplet excited state
bridging ligand-based
triplet excited state
27%,<100 fs73%,<100 fs 535 fs
>3 ps
Pt
~600 ns ~100 ns
H+ reduction at µs time scale
superior electron storage
reservoir
T. Kowacs et al, submitted manuscript.Q. Pan et al, submitted manuscript.
Conclusions
Structure bridging ligand essential for charge separation till µs time scales
Population peripheral ↔ bridging ligands has major impact on H2 formation
state-of-the-art design superior approach
Other research (in brief)
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Ultrafast interactions with plasmonic nanostructures
Immobilization of molecular photocatalysts on inorganic nanoparticles & nanowires
Plasmon-molecule interactions
plasmonic antenna
molecule
inte
nsity
wavelength
antennaabsorption molecule emission
moleculeS0
S1
molecule antennahybrid
Plasmon-molecule interactions
plasmonic antenna
molecule
inte
nsity
wavelength
antennaabsorption molecule emission
moleculeS0
S1
molecule antennahybrid
Plasmon-molecule interactions
plasmonic antenna
molecule
inte
nsity
wavelength
antennaabsorption molecule emission
moleculeS0
S1
molecule antennahybrid
hotspot
Acknowledgment
Sectorplan Physics & Chemistry
University of TwenteQing PanDavid van DuinenFlorian SterlDr. Divya SharmaGerwin SteenDr. Ron GillDr. Christian BlumDr. Jord PrangsmaJeroen KorterikProf. Jennifer Herek
University of Vienna Dr. Leon FreitagProf. Leticia González
Lund University Dr. Jens Uhlig
Technical University of DenmarkMads LaursenDr. Kristoffer Haldrup
University of GroningenProf. Wesley R. BrowneFrancesco Mecozzi
Dublin City UniversityTanja KowacsDr. Mary PrycePhilip LangProf. Han Vos
University of UlmProf. Sven Rau