14 Okt. Spectroscopic ellipsometry at the nanoscale
A new nanomaterial with potential for better batteries, flexible electronics, and clean energy devices is the MXene group. These are ultra-thin materials with a thickness of only a few atoms that conduct electricity, store energy, and interact with light. Until now, however, MXenes (pronounced “max-een”) have mostly been studied in their aggregate form—as thin films consisting of many overlapping flakes. This approach was useful, but it did not allow the unique properties of individual flakes to be investigated and left questions about their true potential unanswered.
Non-invasive with nano precision
Researchers from the Helmholtz-Zentrum Berlin (HZB) and the Hebrew University (HUJI) have now shown for the first time how individual MXene flakes behave when isolated and examined on the nanoscale. According to the researchers, they used a pioneering, patented technique they developed themselves, which they call spectroscopic microellipsometry (SME), to measure the optical, structural, and electronic properties of individual MXene flakes with high lateral resolution and without damaging them. According to the researchers, the method is so precise that it corresponds with nanoscale imaging tools such as atomic force microscopy (AFM) and scanning transmission electron microscopy (STEM), confirming its effectiveness as a non-invasive diagnostic tool.
Suitable for other nanomaterials
Dr. Andreas Furchner from HZB explains: „By measuring the light depolarization of individual MXene flakes, we were able to precisely determine structural thickness variations within the flakes at the nanoscale. We were thrilled to see how well the results matched those obtained using destructive techniques such as STEM.“
MXenes are being researched for a wide range of applications, from ultrafast batteries and water treatment systems to flexible electronics and solar energy harvesting. According to the researchers, understanding the behavior of the material at the single-sheet level is crucial for the development of efficient and scalable devices.
The study not only provides fundamental knowledge about MXenes, but also demonstrates that spectroscopic microellipsometry is suitable for analyzing 2D materials. According to the researchers, this breakthrough could therefore benefit research teams worldwide by enabling them to study new nanomaterials in the same way.
Original publication
[Ralfy Kenaz, Saptarshi Ghosh, Mailis Lounasvuori, Namrata Sharma, Sergei Remennik, Atzmon Vakahi, Hadar Steinberg, Tristan Petit, Ronen Rapaport und Andreas Furchner: Optical, Structural, and Charge Transport Properties of Individual Ti3C2Tx MXene Flakes via Micro-Ellipsometry and Beyond; ACS Nano (2025), DOI: 10.1021/acsnano.5c06938, https://pubs.acs.org/doi/10.1021/acsnano.5c06938]
Source: www.helmholtz-berlin.de
Image: Ralfy Kenaz/Hebrew University, Andreas Furchner/HZB