HZB contributions to special edition on Ultrafast Dynamics with X-ray Methods
At the end of his contribution, Phillippe Wernet makes a great arch from the past (Opticae Thesaurus, 1572) of research with light to the future. © Wikimedia cc
In this theme issue leading researchers discuss
recent work on the ultrafast electronic and structural
dynamics of matter using a new generation of short
duration X-ray photon sources. © Royal Society
In the new special issue of the "Philosophical Transactions of the Royal Society of London", internationally renowned experts report on new developments in X-ray sources and ultrafast time-resolved experiments. HZB physicists have also been invited to contribute.
Almost 350 years after Isaac Newton's ground-breaking paper "Theory of Light and Colors (1671)", the world's oldest scientific journal “Philosophical Transactions” is now once again dedicated to light. The special issue on “Ultrafast Dynamics with X-ray Methods” is aimed at researchers who want to investigate biological, chemical or physical processes and obtain an overview of new developments in light sources and the methods available there. Dynamic processes in materials can be analyzed with high resolution and short pulses at X-ray light sources using ultrafast methods.
Femtoslicing and BESSY VSR
The special issue provides a comprehensive overview of current advances in the generation of ultra-short X-ray pulses by light sources such as Free Electron Lasers (FELs), High Harmonic Generation (HHG) laser sources and synchrotron radiation sources. An article in collaboration with Dr. Karsten Holldack, HZB, presents FEls and Laser sources but also classifies storage ring based methods such as “Femtoslicing” and BESSY VSR. These methods combine highly brilliant synchrotron light with a special time structure and thus allow to address unique experimental questions that cannot be answered at other sources. This complements and expands the portfolio of accelerator-based sources.
Ultra fast spectroscopy for photochemistry
An important contribution is dedicated to photochemistry, an area that focuses on processes such as photosynthesis, the dynamics of which are still largely unexplored. Using ultra-fast spectroscopy at FELs, HHG sources or at the synchrotron with BESSY VSR, methods are now available to measure in detail, for example, excitations of metallo-proteins and the subsequent reactions ; such experiments provide data that are indispensable, for example, for understanding photocatalysis of solar fuels. This article was written by Prof. Dr. Philippe Wernet, formerly a senior scientist at the HZB, and now a professor at Uppsala University, Sweden.
To the publications:
Measurement of ultrafast electronic and structural dynamics with X-rays; J. P. Marangos (ed.)
doi: 10.1098/rsta/377/2145
Recent Advances in Ultrafast X-ray Sources; Robert Schoenlein, Thomas Elsaesser, Karsten Holldack, Zhirong Huang, Henry Kapteyn, Margaret Murnane, Michael Woerner
doi: 10.1098/rsta.2018.0384
Chemical interactions and dynamics with femtosecond X-ray spectroscopy and the role of X-ray free-electron lasers; Philippe Wernet
doi: 10.1098/rsta.2017.0464
- Porous Radical Organic framework improves lithium-sulphur batteriesA team led by Prof. Yan Lu, HZB, and Prof. Arne Thomas, Technical University of Berlin, has developed a material that enhances the capacity and stability of lithium-sulphur batteries. The material is based on polymers that form a framework with open pores (known as radical-cationic covalent organic frameworks or COFs). Catalytically accelerated reactions take place in these pores, firmly trapping polysulphides, which would shorten the battery life. Some of the experimental analyses were conducted at the BAMline at BESSY II.
- Metallic nanocatalysts: what really happens during catalysisUsing a combination of spectromicroscopy at BESSY II and microscopic analyses at DESY's NanoLab, a team has gained new insights into the chemical behaviour of nanocatalysts during catalysis. The nanoparticles consisted of a platinum core with a rhodium shell. This configuration allows a better understanding of structural changes in, for example, rhodium-platinum catalysts for emission control. The results show that under typical catalytic conditions, some of the rhodium in the shell can diffuse into the interior of the nanoparticles. However, most of it remains on the surface and oxidises. This process is strongly dependent on the surface orientation of the nanoparticle facets.
- Shedding light on insulators: how light pulses unfreeze electronsMetal oxides are abundant in nature and central to technologies such as photocatalysis and photovoltaics. Yet, many suffer from poor electrical conduction, caused by strong repulsion between electrons in neighboring metal atoms. Researchers at HZB and partner institutions have shown that light pulses can temporarily weaken these repulsive forces, lowering the energy required for electrons mobility, inducing a metal-like behavior. This discovery offers a new way to manipulate material properties with light, with high potential to more efficient light-based devices.