Date/Time: 04-23-2019 - Tuesday - 05:00 PM - 07:00 PM
Lothar Weinhardt1 3 2 Dirk Hauschild1 3 Monika Blum4 2 Clemens Heske1 3 2

1, Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldsh, , Germany
3, Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, , Germany
2, University of Nevada, Las Vegas, Las Vegas, Nevada, United States
4, Lawrence Berkeley National Laboratory, Berkeley, California, United States

Synchrotron-based soft x-ray spectroscopies, namely soft x-ray absorption (XAS) and emission (XES) spectroscopy, as well as their combination resonant inelastic soft x-ray scattering (RIXS) are powerful techniques to investigate the electronic structure of a variety of systems. We have intensively used these tools for the investigation of applied materials including thin-film solar cells, photoelectrochemical devices, batteries, … (e.g., [1,2,3]). For these systems, in situ and operando studies are often required to answer the pertinent materials questions necessary for a further optimization of the respective device. Due to the photon-in-photon-out nature of XAS, XES, and RIXS with soft x-rays, it is, in fact, possible to investigate gaseous and liquid samples as well, making such in situ and operando investigations possible. However, since these spectroscopies and the corresponding synchrotron beamline environment usually require ultra-high vacuum (UHV) conditions, this requires the development of sophisticated experimental setups.
In this presentation, we will discuss our recent progress in developing suitable environmental cells for in situ and operando soft x-ray studies. Showing selected examples, it will be presented how these techniques give insight into the electronic and chemical properties in the gas and liquid phase, as well as at liquid/solid interfaces. In many cases, the investigated materials are very sensitive to x-ray radiation, which requires careful experimenting with optimized approaches that will be discussed as well.

[1] L. Weinhardt, D. Hauschild, and C. Heske, Advanced Materials, in print (2019).
[2] T.R. Hellstern, D.W. Palm, T.F. Jaramillo, J. Carter, L. Weinhardt, M. Blum, C. Heske, A.D. DeAngelis, K. Horsley, N. Gaillard, and W. Yang, ACS Appl. Energy Mater., in print (2019).
[3] A. Léon, A. Fiedler, M. Blum, A. Benkert, F. Meyer, W. Yang, M. Bär, F. Scheiba, H. Ehrenberg, L. Weinhardt, and C. Heske, J. Phys. Chem. C 121, 5460 (2017).

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