News & Events
News
Appointment of Thomas Lippert as new head of the Laboratory for Multiscale Materials Experiments (LMX)
Starting 1. December 2022, Prof. Dr. Dr. Thomas Lippert will be the new head of the Laboratory for Multiscale Materials Experiments (LMX). He follows Prof. Dr. Laura Heyderman, our first laboratory head who successfully formed and established the LMX in the PSI landscape as a Centre of Materials.
TFI goes TecDays
In July 2022, two PhDs of our Thin Films and Interfaces (TFI) Group offered a practical teaching module to pupils at the Kantonsschule Stadelhofen as part of the Swiss TecDays. These are one-day events at Swiss grammar schools, organized by the Schweizerische Akademie der Technischen Wissenschaften (SATW), to support and strengthen technology education at schools. By bringing together pupils and experts from industry, universities, or research institutions, TecDays aims to raise an early awareness for technology and science.
Woman in Science
Congratulations to our former postdoc, Alexandra Palla-Papavlu (4th from the left), for winning the L’Oreal Prize for Woman in Science(link is external) in the category Physics in Romania
Scientific Highlights
Surface oxidation/spin state determines oxygen evolution reaction activity of cobalt-based catalysts in acidic environment
Co-based catalysts are promising candidates to replace Ir/Ru-based oxides for oxygen evolution reaction (OER) catalysis in an acidic environment. However, both the reaction mechanism and the active species under acidic conditions remain unclear. In this study, by combining surface-sensitive soft X-ray absorption spectroscopy characterization with electrochemical analysis, we discover that the acidic OER activity of Co-based catalysts are determined by their surface oxidation/spin state.
A practical guide to pulsed laser deposition
Nanoscale thin films are widely implemented across a plethora of technological and scientific areas, and form the basis for many advancements that have driven human progress, owing to the high degree of functional tunability based on the chemical composition. Pulsed laser deposition is one of the multiple physical vapour deposition routes to fabricate thin films, employing laser energy to eject material from a target in the form of a plasma ...
Momentum-resolved electronic structure of LaTiO2N photocatalysts by resonant Soft-X-ray ARPES
Oxynitrides are promising materials for visible light-driven water splitting. However, limited information regarding their electron-momentum resolved electronic structure exists. Here, with the advantage of the enhanced probing depth and chemical state specificity of soft-X-ray ARPES, we determine the electronic structure of the photocatalyst oxynitride LaTiO2N and monitor its evolution as a consequence of the oxygen evolution reaction. After the photoelectrochemical reactions, we observe a partial loss of Ti- and La-N 2p states, distortions surrounding the local environment of titanium atoms and, unexpectedly, an indication of an electron accumulation layer at or near the surface, which may be connected with either a large density of metallic surface states or downward band bending. The distortions and defects associated with the titanium 3d states lead to the trapping of electrons and charge recombination, which is a major limitation for the oxynitride LaTiO2N. The presence of an accumulation layer and its evolution suggests complex mechanisms of the photoelectrochemical reaction, especially in cases where co-catalysts or passivation layers are used.