Fundamentals and Dynamics of Energy Transport and Conversion The Advanced Photon Source is funded by the U.S. Department of Energy Office of Science Advanced Photon Source 9700 S. Cass Ave. Argonne, IL USA Opportunities for time-resolved x-ray science at the Advanced Photon Source APS Standard Operating Mode Provides a large flux in well separated pulses X-rays 6.52 MHz 153 ns 80 ps FWHM X-ray pulse spacing is large enough to isolate signal from individual x- ray pulses ~10 6 photons/pulse at 7ID-D ~10 10 photons/pulse at 14ID-B Diverse pump sources: Optical, electrical, mechanical and THz excitations Electronic origin of photoinduced strain in multiferroics Wen, et al., Phys. Rev. Lett. 110, (2013) Schick, et al., Phys. Rev. Lett. 112, (2014) 400 nm 35 nm BiFeO 3 on SrTiO 3 (001) Using ultrafast optical and x-ray probes, we found optically excited carriers screen the depolarization field, which gives rise to significant localized strain as a result of inverse piezoelectric effect. Motivation: Controlling the interplay of electronic, magnetic, optical, mechanical, and thermal properties of materials for efficient energy transport and conversion t<0t=0 t>0 Complex chemical reactions can be initiated by light and recorded on physically relevant time scales, paving the way for the exploration of of life’s most sophisticated processes. Y. O. Jung et al., Nature Chem. 5, 212(2013) J. Chen, et al., Appl. Phys. Lett. 102, (2013). Visualizing trans-cis isomerization pathways Time- and momentum- resolved heat transport Ultrafast Materials Science: Understanding and controlling energy transport and conversion among multiple degrees of freedom Q 5um The spatiotemporal-resolved structural probe reveals the deviation of the relaxation process from a sinusoidal profile that quantitatively measure the in-plane transport processes. Introduction The time-resolved research program at the Advanced Photon Source is targeted at understanding the fundamentals of energy transport and conversion at multi- energy, length and time scales utilizing a suite of advanced ultrafast hard x-ray probes localized at Sector 7, 11 and 14. Spin Charge Lattice Orbital c a Optical intensity I(x,t) Position (µm) Intensity (a.u) θ oθ o Delay (ns) Energy transport in nanostructured materials BiFeO 3 FeRh Ultrafast Chemical Science: Elucidating the mechanisms of light induced chemical processes Dye Sensitized Solar Cells Natural photosynthesis Molecular machines Artificial photosynthesis solar fuels: Light → chemical energy Artificial photosynthesis solar cells: Light → electricity Combined Techniques for Complimentary Information XAS (absorption) XES (emission) XRS (scattering) Kα, Kβ sensitive to electronic structure, not geometric structure (spin and oxidation state, electronic correlations) Determine structures of transient intermediates Insight into solvent shell rearrangements XANES: sensitive to electronic and geometric structure (oxidation state, valence orbital occupancy, charge transfer) EXAFS: local bond distances and coordination numbers Element specific, sensitive to local structure Sensitive to all species in the solvent Valence-to-Core sensitive to chemically relevant orbitals Motivation: harnessing the power of light All those techniques can now be applied to study transient states ! X-ray absorption spectroscopy X-ray emission spectroscopy X-ray diffuse scattering -direct probe of spin state -insight into solvent shell rearrangements Kα Kβ -electronic and geometric structure Excited state fraction Input for XAS analysis Input for scattering analysis EXAFS yields change in bond length Yields excited state geometric structure KB Mirrors X-rays Ion chamber Pilatus Laser APD 1 m Rowland circle Analyzer crystal Scintillator 3 ft. x 3 ft. table Liquid jet Capturing excited state structures at high precision by using full APS flux First demonstration of combined techniques in a pump-probe experiment Low spin  650 ps h Aqueous [Fe(bpy) 3 ] 2+ High spin K. Haldrup et al., J.Phys Chem. A 116, 9878 (2012) G. Vanko et al, JESRP 188, 166 (2013) Sector 7ID-D Combined techniques setup Sector 7ID-D Combined techniques setup Using flux demanding techniques for time resolved studies: efficient detection at high rep-rate Ex: Von Hamos crystal analyzer for TR-XES J. Szlachetko et al., RSI 83, (2012). X-ray emission energy Incident x-ray energy ZnO nanoparticles: Observe evolution of charge distribution Laser excitation and x-ray 1.3 MHz ZnO (35 nm particles) in nm Optical pulse promotes electrons in conduction band Only ~1% excited state fraction Time-resolved RIXS difference map Data consistent with increased electron density on Zn centers Also demonstrated simultaneous measurement of K , K  and Valence to Core XES K  100 ps delay K  100 ps delayK  ground state K  ground state Photosystem 1 e-e- Relay Catalyst Photosensitizer (PS) Relay (R) Catalyst (C) R Bio- inspiration Photosensitizer Phys. Chem. Lett. 4, 1972 (2013). Natural photosynthesis Interfacial electron transfer in Dye-sensitized solar cell h VB CB Dye (TiO 2 ) n e-e- VB CB Dye (TiO 2 ) n + - X-ray probe J. Phys. Chem. Lett. 2, 628 (2011). Angew. Chem. Int. Ed. 51, (2012). Electron transfer inside a biomimetic supramolecular complex for solar fuel catalysts Science 337, 1200 (2012). Electron transport inside iron oxide nanoparticles Sector 11ID-D A versatile Time resolved X-Ray Absorption setup Sector 11ID-D A versatile Time resolved X-Ray Absorption setup Showcase experiments using X-ray absorption Energy Conversion Resolution: ~260 nm, ~80 ps Spatiotemporally resolved hard x-ray probe High repetition rate lasers to fully exploit high flux of the APS Tunable (  m) Up to 1 MHz 250 fs Light Conversion PHAROS New! 266 nm 2.5 W (4 600 kHz Time Bandwidth DUETTO 50 kHz MHz 10 ps and 130 ps Electric field pulse THz Laser shock excitation Optical excitation Energy Transport 0.4% strain Electric-field-driven domain dynamics P. Chen, et al., Phys. Rev. Lett. 110, (2013) The time-resolved changes of the diffuse scattering show primarily a quasi-thermal phonon distribution that is established in 100 ps and that follows the time-scale of thermal transport. Superionic phase transition T. A. Miller et al., Nature Comm. 4, 1369 (2013) H. Wen, G. Doumy, B. Adams, A. D. DiChiara, E. M. Dufresne, T. Graber, Y. Li, A. M. March, Q. Kong, A. R. Sandy, S. H. Southworth, D. A. Walko, J. Wang, X. Zhang, Y. Zhu Time-Resolved Research, Atomic Molecular and Optical Physics, and Structural Science Groups, X-ray Science Division, Advanced Photon Source, Argonne National Laboratory Position (µm) PbO SrO PbO TiO 2 SrO … …