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

e-

e-

Artificial photosynthesisz-scheme

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e-

e-

e-

e-

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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

e-

e-

e-

e-

e-

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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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gani

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ode

Research line

www.its.caltech.edu

inor

gani

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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

e-

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

ere

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