Impact of composition and nanometer scale disorder in transparent conductive oxides (DisCO Project)
The DisCO project aims at the development and investigation of transparent conductive oxides based on earth-abundant materials. It is a Sinergia project where three different groups are involved: the material synthesis and characterization group, based at EPFL’s Photovoltaics and Thin Film Electronics Laboratory in Neuchâtel, the functional imaging group, based in Lausanne (CIME-LSME), and the material modeling group, based at the Department of Physics, University of Basel. The deep interaction between groups enables the design of high quality materials. In particular, the role of functional imaging is of extreme importance to understand how structural changes affect the optoelectronic behavior of the materials. This is made possible by the combination of in situ and ex situ analyses made using techniques such as Transmission Electron Microscopy, X-ray Diffraction and Differential Scanning Calorimetry.
People involved in the project:
PhD students: Federica Landucci (LSME/PV-Lab) – Esteban Rucavado – Miglè Grauzinyte
Post Docs/Team leaders: Monica Morales-Masis – Quentin Jeangros
Responsibles/Prof: Aïcha Hessler-Wyser – Christophe Ballif – Cécile Hébert – Stefan Goedecker – Rafal Dunin-Borkowski
Advanced analytical electron microscopy applied to Solid Oxide Fuel Cell materials and their degradation
The aim of this PhD thesis is to improve our understanding of the degradation of solid oxide fuel cell (SOFC) components which are subject to extreme conditions. In order to reach this goal, an experimental method to characterize the first hours of ageing of several SOFC components has to be defined, using advanced electron microscope methods and mixing in-situ observation and post-test analyses. Three components are under focus:
– the ceramic composite anode (nickel – Yttrium stabilized zirconium)
– the steel interconnect and its coating (cobalt cerium coating on Sandvik Sanergy High-Temperature steel)
– the glass-ceramic seals (Barium base glass ceramic seals from Schott)
Quantification of minor and trace elements by STEM-EDX/EELS
The aim of this project is to achieve the highest possible precision for quantification of minor or even trace elements at the nanoscale, by taking advantage of simultaneous acquisition of the low loss and core loss EELS signals, as well as EDXS signals, in one spatially-resolved STEM scan, and then introducing PCA and other statistical methods from the MSA family to mine the spectral image datasets. The experimental work will be done using the FEI Titan Themis at CIME, with spherical aberration correction, monochromated electron source, and fast/high sensitivity spectroscopy capabilities. The developed methodology will be utilized to investigate dopant quantity and distribution in minerals and transparent alumina samples, thus providing solid evidence for interpreting their physical properties.
PhD student (LSME): Hui Chen
PhD advisor: Prof. Cécile Hébert