TY  - JOUR
A1  - Zamponi, Flavio
A1  - Penfold, Thomas J.
A1  - Nachtegaal, Maarten
A1  - Lübcke, Andrea
A1  - Rittmann, Jochen
A1  - Milne, Chris J.
A1  - Chergui, Majed
A1  - van Bokhoven, Jeroen A.
T1  - Probing the dynamics of plasmon-excited hexanethiol-capped gold nanoparticles by picosecond X-ray absorption spectroscopy
JF  - physical chemistry, chemical physics : PCCP
N2  - Picosecond X-ray absorption spectroscopy (XAS) is used to investigate the electronic and structural dynamics initiated by plasmon excitation of 1.8 nm diameter Au nanoparticles (NPs) functionalised with 1-hexanethiol. We show that 100 ps after photoexcitation the transient XAS spectrum is consistent with an 8% expansion of the Au–Au bond length and a large increase in disorder associated with melting of the NPs. Recovery of the ground state occurs with a time constant of ∼1.8 ns, arising from thermalisation with the environment. Simulations reveal that the transient spectrum exhibits no signature of charge separation at 100 ps and allows us to estimate an upper limit for the quantum yield (QY) of this process to be <0.1.
KW  - TiO2 nanoparticles
KW  - diimine-complexes
KW  - electron-transfer
KW  - supported gold
KW  - visible-light
KW  - water
KW  - surface
KW  - reactivity
KW  - nanoclusters
KW  - excitation
Y1  - 2014
U6  - https://doi.org/10.1039/c4cp03301a
SN  - 1463-9076
SN  - 1463-9084
VL  - 2014
IS  - 16
SP  - 23157
EP  - 23163
ER  - 
TY  - JOUR
A1  - Herzog, Marc
A1  - Leitenberger, Wolfram
A1  - Shayduk, Roman
A1  - van der Veen, Renske Marjan
A1  - Milne, Chris J.
A1  - Johnson, Steven Lee
A1  - Vrejoiu, Ionela
A1  - Alexe, Marin
A1  - Hesse, Dietrich
A1  - Bargheer, Matias
T1  - Ultrafast manipulation of hard x-rays by efficient Bragg switches
N2  - We experimentally demonstrate efficient switching of the hard x-ray Bragg reflectivity of a SrRuO3 /SrTiO3 superlattice by optical excitation of large-amplitude coherent acoustic superlattice phonons. The rocking curve changes drastically on a 1 ps timescale. The (0 0 116) reflection is almost extinguished (Delta R/R-0=-0.91), while the (0 0 118) reflection increases by more than an order of magnitude (Delta R/R-0=24.1). The change of the x-ray structure factor depends nonlinearly on the phonon amplitude, allowing manipulation of the x-ray response on a timescale considerably shorter than the phonon period. Numerical simulations for a superlattice with slightly changed geometry and realistic parameters predict a switching-contrast ratio Delta R/R-0 of 700 with high reflectivity.
Y1  - 2010
UR  - http://apl.aip.org/
U6  - https://doi.org/10.1063/1.3402773
SN  - 0003-6951
ER  - 
TY  - JOUR
A1  - Zamponi, Flavio
A1  - Penfold, Thomas J.
A1  - Nachtegaal, Maarten
A1  - Luebcke, Andrea
A1  - Rittmann, Jochen
A1  - Milne, Chris J.
A1  - Chergui, Majed
A1  - van Bokhoven, Jeroen A.
T1  - Probing the dynamics of plasmon-excited hexanethiol-capped gold nanoparticles by picosecond X-ray absorption spectroscopy
JF  - Physical chemistry, chemical physics : a journal of European Chemical Societies
N2  - Picosecond X-ray absorption spectroscopy (XAS) is used to investigate the electronic and structural dynamics initiated by plasmon excitation of 1.8 nm diameter Au nanoparticles (NPs) functionalised with 1-hexanethiol. We show that 100 ps after photoexcitation the transient XAS spectrum is consistent with an 8% expansion of the Au-Au bond length and a large increase in disorder associated with melting of the NPs. Recovery of the ground state occurs with a time constant of similar to 1.8 ns, arising from thermalisation with the environment. Simulations reveal that the transient spectrum exhibits no signature of charge separation at 100 ps and allows us to estimate an upper limit for the quantum yield (QY) of this process to be <0.1.
Y1  - 2014
U6  - https://doi.org/10.1039/c4cp03301a
SN  - 1463-9076
SN  - 1463-9084
VL  - 16
IS  - 42
SP  - 23157
EP  - 23163
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  -