Near-Ambient-Pressure XPS for TCM research
Dr. Mirko Weidner
SPECS Surface Nano Analysis GmbH, Berlin
Photoelectron spectroscopy has historically proven to be a powerful tool in TCM research, as
it is the only technique that enables direct measurement of a material’s electronic structure,
revealing elemental oxidation states, valence band structures and Fermi Level position, all of
which are highly relevant properties in a TCM. Due to its extreme surface sensitivity, the
method also allows the direct and indirect characterization of thin film interfaces, which are
known to be crucial for the performance of electronic devices of any kind.
One of the major drawbacks of XPS, the limitation to ultra-high vacuum (UHV) conditions,
has however limited the collection of data to fundamental material characterization studies in
many cases, prohibiting the investigation of device-like structures. Recent advances in the
field of near-ambient-pressure (NAP) XPS have lifted this limitation, allowing researchers to
introduce gas or liquid phase into the measurement environment. In regard to TCM research,
this opens up exciting new possibilities such as: in-operando measurements of TiO
2
photocatalysts, water splitting devices or environmental sensors; live monitoring of the
annealing-induced changes in wet-chemically processed TCM films; measuring solid-liquid
interfaces for applications such as electrochromic windows or other transparent devices
containing liquid electrolytes.
The general experimental approach and early measurement results tailored specifically to
demonstrate usage scenarios of NAP-XPS in TCM research are presented in this poster.
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