News

August 2020

WITec kündigt Virtual Raman Imaging Poster Summit 2020 an

Online-Konferenz zum wissenschaftlichen Austausch in der Raman-Community

Ulm, Deutschland
11. August 2020

WITec GmbH, Branchenführer in der Entwicklung und Herstellung hochleistungsfähiger Raman-Mikroskope, veranstaltet vom 28. September bis 2. Oktober 2020 zum ersten Mal den Virtual Raman Imaging Poster Summit.

Die Online-Konferenz bietet Wissenschaftlern weltweit die Möglichkeit, ihre Anwendungen  der Raman-Mikroskopie bequem von zu Hause aus zu präsentieren und zu diskutieren. Die Beiträge gliedern sich in die Themengebiete Lebenswissenschaften, Biomedizin und pharmazeutische Forschung, Materialwissenschaften, Umwelt- und Geowissenschaften sowie korrelative Raman-Mikroskopie.

Die virtuelle Konferenz ersetzt in diesem Jahr das Raman Imaging Symposium als wichtigste Veranstaltung für chemische Bildgebung und Spektroskopie. Das alljährlich von WITec veranstaltete Symposium ist für die Vielfalt der dort vertretenen Disziplinen und den wissenschaftlichen Austausch in geselliger Atmosphäre bekannt. Die virtuelle Poster-Konferenz wird an diese Tradition anknüpfen, aufgrund der anhaltenden Pandemie jedoch im Onlineformat stattfinden.

“Wir sind sehr gespannt auf die neuesten Anwendungen der Raman-Mikroskopie“, versichert Harald Fischer, Marketing Direktor bei WITec. “Auch in diesen unsicheren Zeiten steht die Wissenschaft nicht still und Forscher sind natürlich von ihren neuesten Entdeckungen begeistert. Der Virtual Raman Imaging Poster Summit ist 2020 die beste Plattform, um diese Begeisterung zu teilen.”

Über eine Chatfunktion werden die Teilnehmer Fragen zu den Postern stellen und die vorgestellten Forschungsergebnisse diskutieren können. Der Gewinner des Posterpreises wird durch eine Abstimmung unter allen Teilnehmern ermittelt werden. Abstracts für Posterbeiträge können bis zum 15. September 2020 eingereicht werden.

Weitere Informationen finden Sie auf der Webseite des Virtual Poster Summit 2020:
www.raman-symposium.com/virtual-poster-summit

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Juli 2020

Correlative high-resolution imaging of TMDs – Raman, SHG and PL imaging of an MoS2 flake

Two-dimensional (2D) materials such as transition metal dichalcogenides (TMDs) are receiving increasing attention due to their unique optical and electronic properties. Their possible applications include the production of transistors, photo detectors, light emitting diodes (LEDs) and photovoltaic cells. In order to produce high-quality devices, synthesis processes must be evaluated efficiently. Thus, non-destructive imaging techniques are required for monitoring crystal properties and features such as grain boundaries, layer number, defect density, doping and strain fields.

In our new application note, we present a series of measurements of CVD-grown mono-layer molybdenum disulfide (MoS2), which illustrate the advantages of correlative Raman, second harmonic generation (SHG) and photoluminescence (PL) microscopy for investigating TMDs. All measurements were performed at the same area of interest using a WITec alpha300 microscope equipped with a 532 nm laser for Raman and PL imaging and a picosecond-pulsed 1064 nm laser for SHG excitation.

Strain fields in the crystal were visualized by Raman and PL imaging, as both the frequency of the E2g Raman mode (upper left image) and the wavelength of the PL signal (lower left image) were red-shifted in the same areas. Rim effects around the border of the MoS2 flake were clearly visible in the PL image (lower left image), as well as in the image of the A1g Raman mode (see the attached application note).

SHG microscopy is sensitive to changes in crystal orientation and symmetry and visualized grain boundaries in the MoS2 flake (upper right picture). Additionally, polarization-dependent SHG measurements can identify the crystal orientation and reveal strain fields. To this end, the excitation polarization is rotated while recording the intensity of the SHG signal component that has the same polarization as the incident light. Polarization series were recorded in a fully automated manner at three positions of the MoS2 flake (lower right picture). The distinct patterns observed indicate different strain levels.

Correlative Raman, PL and SHG imaging yields complementary and consistent information for characterizing single-layer TMD crystals by visualizing features of the crystal structure, such as grain boundaries or strain fields, without damaging the sample.

For more details, including further pictures and references, please download our 2-page application note on correlative high-resolution imaging of MoS2.

Correlative Raman, PL and SHG imaging of a mono-layer MoS2 flake. 200 nm per pixel for all images. For a detailed description and more pictures, please download the attached application note.

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Juli 2020

Graphene fine structures visualized by high-resolution confocal Raman imaging

Raman imaging is a non-destructive tool for evaluating the quality of 2D materials as strain, doping, defects and layer number can be assessed. These two large-area Raman images visualize defect density (top) and strain fields (bottom) in a CVD-grown graphene flake at high spatial resolution (100 nm per pixel). They were acquired using the fully automated Raman microscope alpha300 apyron equipped with a 532 nm laser for excitation and TrueSurface for focus stabilization.

The upper Raman image is color-coded according to the intensity of the D-band in the recorded Raman spectra. It visualizes crystal defects, as the D-band intensity depends on the defect density in the carbon lattice. The observed width of the fine structures is very close to the diffraction limited lateral resolution achievable with 532 nm excitation, demonstrating the microscope’s high performance.

The lower Raman image is color-coded according to the peak position of the 2D-band, which was quantified by a Pseudo-Voigt fit. The image visualizes local strain/doping effects, as the frequency of the 2D-band is influenced by local strain and, to a lesser extent, by doping.

These examples offer conclusive proof that with an advanced and highly sensitive system, Raman imaging alone can provide access to the finest details of graphene crystal properties.

High-resolution Raman imaging of CVD-grown graphene (100 nm per pixel). Top: Raman image representing the intensity of the D-band, visualizing crystal defects. Bottom: Raman image representing the frequency of the 2D-band, visualizing local strain/doping effects.

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Juli 2020

ParticleScout ist einer der Finalisten des Wiley Analytical Science Award 2021

ParticleScout, unser Softwaretool für automatisierte Mikropartikelanalyse mit Raman-Spektroskopie, gehört zu den Finalisten des Wiley Analytical Science Award 2021. Wir sind glücklich und stolz über diese Auszeichnung.

Eine unabhängige Jury aus Forschern und Industrierepräsentanten hat ParticleScout als eines von sechs Produkten in der Kategorie "Spektroskopie & Mikroskopie" nominiert. Die Leser von “GIT Labor-Fachzeitschrift” und “Imaging & Microscopy” sowie alle Nutzer des Wiley Analytical Science Portals können ab sofort bis zum 30. September auf der folgenden Webseite für ihren Favoriten abstimmen.

www.was-award.com

Wünschen Sie uns Glück oder, noch besser, unterstützen Sie uns, indem Sie ParticleScout Ihre Stimme geben.

Das fortschrittliche Softwaretool ParticleScout charakterisiert Mikropartikel, einschließlich Mikroplastik in der Umwelt, mit Raman-Spektroskopie. Mehr Informationen erhalten Sie auf unserer Produktseite:

www.witec.de/de/produkte/zubehoer/particlescout

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Juli 2020

Researchers in India use a WITec Raman microscope to detect RNA viruses

A paper just published in the Journal of Biophotonics describes how Raman spectoscopy can enable the detection of RNA viruses in human saliva. Dr. Amit Dutt's group at the Tata Memorial Centre, based in Mumbai, obtained raw data with a WITec Raman microscope and carried out statistical analysis to find a set of 65 Raman spectral features that positively identified the presence or absence of viruses in a sample.

The analysis could be performed in less than a minute without adding a reagent to increase the signal. Their signal set was able to achieve 92.5% sensitivity and 88.8% specificity.  

“This conceptual framework to detect RNA viruses in saliva could form the basis for field application of Raman Spectroscopy in managing viral outbreaks, such as the ongoing COVID-19 pandemic,” said the researchers.

https://onlinelibrary.wiley.com/doi/abs/10.1002/jbio.202000189

Scientists in the research group of Dr. Amit Dutt, who used Raman microscopy to detect RNA viruses in human saliva samples.

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