TY - CONF A1 - Wegner, Karl David T1 - Ag₂S nanocrystals as next-generation, heavy-metal free SWIR emitter for biomedical imaging and sensing applications N2 - There is a growing interest in the exploitation of the short-wave infrared (SWIR), which refers to the wavelength band of light between 900 nm and 2500 nm. Luminophores that emit in the SWIR are used in various areas of telecommunications, photovoltaics, security systems (night vision), and in biomedicine. In particular for biomedical applications, the SWIR range is highly promising because light scattering, absorption, and autofluorescence of tissue and biological compounds are strongly reduced compared to the visible (400–700 nm) and NIR (~700–900 nm). The benefits of SWIR-emissive QDs have been demonstrated for a variety of applications, such as in thermal sensing, as photoelectrochemical biosensor, in in vivo vascular imaging, and for fluorescence-guided surgery. Full exploitation of SWIR photoluminescence (PL) imaging and sensing is currently hampered by i.) a lack of suitable advanced nanomaterials with a high PL quantum yield (PL QY) and a high brightness, that can be used safely in vivo and ii.) a lack of quantitative and reliable data on the optical properties of many SWIR emitters. Promising nanomaterials for the SWIR are heavy metal-free Ag2S quantum dots (QDs). Aiming for the development of SWIR advanced nanomaterials with optimum performance, we have dived deeper into the photophysical processes occurring in these nanomaterials, thereby exploring in depth how the environment such as temperature, surface ligand composition, and the incorporation of transition metals influence the optical properties Ag2S QDs. We observed a strong enhancement of the SWIR emission of upon addition of metal ions such as Zn2+, yielding PL quantum yields of about 10% and thus making them highly suitable for non-invasive deep imaging of vascular networks and 3D fluid flow mapping. T2 - Shining a light on biomedical and energy applications (Shift) CY - Tenerife, Spain DA - 13.10.2025 KW - Quantum dots KW - Short-wave infrared KW - SWIR KW - Spectroscopy KW - Photoluminescence KW - Quantum yield PY - 2025 AN - OPUS4-64673 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chazeau, E. A1 - Fabre, C. A1 - Privat, M. A1 - Godard, A. A1 - Racoeur, C. A1 - Bodio, E. A1 - Busser, B. A1 - Wegner, Karl David A1 - Sancey, L. A1 - Paul, C. A1 - Goze, C. T1 - Comparison of the In Vitro and In Vivo Behavior of a Series of NIR-II-Emitting Aza-BODIPYs Containing Different Water-Solubilizing Groups and Their Trastuzumab Antibody Conjugates N2 - The development of new fluorescent organic probes effective in the NIR-II region is currently a fast-growing field and represents a challenge in the domain of medical imaging. In this study, we have designed and synthesized an innovative series of aza-boron dipyrromethenes emitting in the NIR-II region. We have investigated the effect of different water-solubilizing groups not only on the photophysical properties of the compounds but also on their in vitro and in vivo performance after bioconjugation to the antibody trastuzumab. Remarkably, we discovered that the most lipophilic compound unexpectedly displayed the most favorable in vivo properties after bioconjugation. This underlines the profound influence that the fluorophore functionalization approach can have on the efficiency of the resulting imaging agent. KW - NIR-II KW - In vivo imaging KW - Fluorescence KW - Spectroscopy KW - Antibody conjugates PY - 2024 DO - https://doi.org/10.1021/acs.jmedchem.3c02139 SN - 1520-4804 VL - 67 IS - 5 SP - 3679 EP - 3691 PB - ACS Publications CY - Washington, DC AN - OPUS4-59607 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - de Camargo, Andrea Simone Stucchi T1 - Spectroscopy Lectures N2 - As a guest professor of FUNGLASS, I delivered 3 lectures on spectroscopy to the Graduate School Program, the postdoctoral fellows and other researchers: 1) Introduction to spectroscopy applied to solid state materials (with focus on glass and glass ceramics); 2) Vibrational spectroscopy (Infrared and Raman); 3) Electron Paramagnetic Resonance T2 - FunGlass CY - Trencín, Slovakia DA - 03.06.2024 KW - Spectroscopy KW - Radiation-matter interaction KW - FT-IR KW - Raman KW - EPR PY - 2024 AN - OPUS4-60367 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Deumer, J. A1 - Andresen, Elina A1 - Gollwitzer, C. A1 - Schürmann, R. A1 - Resch-Genger, Ute T1 - Adding More Shape to Nanoscale Reference Materials-LiYF4:Yb,Tm Bipyramids as Standards for Sizing Methods and Particle Number Concentration N2 - The increasing industrial use of nanomaterials calls for the reliable characterization of their physicochemical key properties like size, size distribution, shape, and surface chemistry, and test and reference materials (RMs) with sizes and shapes, closely matching real-world nonspheric nano-objects. An efficient strategy to minimize efforts in producing nanoscale RMs (nanoRMs) for establishing, validating, and standardizing methods for characterizing nanomaterials are multimethod nanoRMs. Ideal candidates are lanthanide-based, multicolor luminescent, and chemically inert nanoparticles (NPs) like upconversion nanoparticles (UCNPs), which can be prepared in different sizes, shapes, and chemical composition with various surface coatings. This makes UCNPs interesting candidates as standards not only for sizing methods, but also for element-analytical methods like laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS), quantitative bioimaging methods like X-ray fluorescence computed tomography (XFCT), and luminescence methods and correlative measurements. Here, we explore the potential of two monodisperse LiYF4:Yb,Tm bipyramids with peak-to-peak distances of (43 ± 2) nm and (29 ± 2) nm as size standards for small-angle X-ray scattering (SAXS) and tools for establishing and validating the sophisticated simulations required for the analysis of SAXS data derived from dispersions of nonspheric nano-objects. These SAXS studies are supplemented by two-dimensional (2D)-transmission electron microscopy measurements of the UCNP bipyramids. Additionally, the particle number concentration of cyclohexane dispersions of these UCNP bipyramids is determined by absolute SAXS measurements, complemented by gravimetry, thermogravimetric analysis (TGA), and inductively coupled plasma optical emission spectrometry (ICP-OES). This approach enables traceable particle number concentration measurements of ligand-capped nonspheric particles with unknown chemical composition. KW - Fluorescence KW - Upconversion nanoparticles KW - SAXS KW - Particle number concentration KW - Reference material KW - Traceability KW - Quality assurance KW - Quantum yield KW - Spectroscopy KW - Synthesis KW - Quantification KW - NanoRM KW - Nano KW - Particle KW - Bipyramid KW - Reference data KW - Simulation PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-617940 DO - https://doi.org/10.1021/acs.analchem.4c03641 SP - 1 EP - 8 PB - ACS Publications AN - OPUS4-61794 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wegner, Karl David T1 - SWIR luminescent nanomaterials – key chemical parameters for bright probes for in vivo bioimaging N2 - A current challenge for studying physio-pathological phenomena and diseaserelated processes in living organisms with non-invasive optical bioimaging is the development of bright optical reporters that enable deep tissue penetration, a high detection sensitivity, and a high spatial and temporal resolution. The focus of this project are nanomaterials, which absorb and emit in the shortwave infrared (SWIR) between ~900–2500 nm where scattering, absorption, and autofluorescence of the tissue are strongly reduced compared to the visible and NIR. T2 - QD2024 - 12th International Conference on Quantum Dots CY - Munich, Germany DA - 18.03.2024 KW - Quantum dots KW - Advanced nanomaterials KW - Fluorescence KW - Quality assurance KW - Gold nanocluster KW - Shortwave infrared KW - Spectroscopy KW - Bioimaging PY - 2024 AN - OPUS4-59783 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nehring, Grzegorz T1 - Breaking the limits of the non-destructive instrumental analysis of writing inks N2 - The ink analysis protocol developed through cooperation between the Bundesanstalt für Materialforschung und -prüfung in Berlin and the Centre for the Study of Manuscript Cultures at the University of Hamburg involves the use of imaging techniques for ink screening, followed by spectroscopic analysis. In our presentation, we will begin by briefly reviewing the history of writing inks and discussing the three main categories: carbon-based inks, plant, and iron-gall inks. We will address their chronology, precursors, and mixed forms, as well as the features that allow for their identification. Then, we will present the techniques we use in ink analysis, whereby we would like to highlight the limitations, advantages, and disadvantages of each approach. Finally, we will discuss the new mass-spectrometric method based on micro-sampling and using atmospheric solid analysis probe (ASAP). T2 - Future of the Past CY - Torun, Poland DA - 14.06.2023 KW - Ink analyses KW - Spectroscopy KW - Mass spectroscopy PY - 2023 AN - OPUS4-58882 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR ED - Schmidt-Grund, R. ED - Sturm, C. ED - Hertwig, Andreas T1 - Topical issue: Ellipsometry N2 - Ellipsometry is a matured experimental method, whose roots reach back into the early phase of modern optics itself. It is often attributed to be invented by Paul Drude in the last decade of the 19th century, but similar techniques had already been applied for years before Drude started his work. With this Special Issue about ellipsometry and related techniques, we hope to bring more attention to this method and advance and propagate it to be used by a broader community. KW - Spectroscopy KW - Ellipsometry KW - Surfaces KW - Thin films KW - Advanced optics KW - Optical measurement technology PY - 2022 UR - https://www.degruyter.com/journal/key/aot/11/3-4/html#contents SN - 2192-8584 SN - 2192-8576 VL - 11 IS - 3-4 SP - 47 EP - 147 PB - De Gruyter CY - Berlin AN - OPUS4-55468 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Stephan-Scherb, Christiane ED - Schorr, S. ED - Weidenthaler, C. T1 - Crystallographic challenges in corrosion research N2 - High-temperature corrosion is a widespread problem in various industries. As soon as a hot and reactive gas (CO2, O2, H2O, SO2, NOx, etc.) is in contact with a solid, physico-chemical processes at the surface and interfaces lead to material degradation. The processes are dynamic and controlled by thermodynamic and kinetic boundary conditions. Whether a reaction product is protective or not depends on various factors, such as chemical composition of the solid and the reactive media, surface treatment as well as diffusion and transport paths of cations and anions. Resulting chemical and structural inhomogeneities with the corrosion layers are characterized by off stoichiometry within cationic and anionic sub lattices. The competitive processes can be studied by various techniques of applied crystallography. This chapter gives an overview on the challenges of chemical-structural Analysis of reaction products by crystallographic methods such as X-ray diffraction and X-ray near-edge structure spectroscopy and scanning electron microscopy electron backscatter diffraction (SEM-EBSD) for corrosion science. KW - High-temperature corrosion KW - Oxidation KW - Diffraction KW - Spectroscopy KW - Oxides PY - 2021 DO - https://doi.org/10.1515/9783110674910-009 SP - 291 PB - De Gruyter ET - 1 AN - OPUS4-52903 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stephan-Scherb, Christiane T1 - Novel insights into high temperature corrosion phenomena by advanced X-ray methods N2 - A variety of materials of technological interest change their properties through contact with reactive media. Solid-gas reactions lead to a variety of reaction products on the surfaces and internal interfaces. The observation of nucleation and growth processes in the environment where they occur (in situ) from a chemical-structural perspective is especially challenging for aggressive atmospheres. The talk presents innovative approaches to study corrosion mechanisms using advanced X-ray methods. Using energy dispersive X-ray diffraction and X-ray absorption spectroscopy in different tailor made environmental reaction chambers, valuable insights into high temperature oxidation and sulfidation processes were gained. Fe-based alloys were exposed to hot and reactive atmospheres containing gases like SO2, H2O and O2 at 650°C. During the gas exposure the tailor made reaction chambers were connected to a high energy diffraction end station at the synchrotron. The crystallization and growth of oxide and sulfide reaction products at the alloy surfaces were monitored by collecting full diffraction pattern every minute. Careful examination of shape and intensity of phase-specific reflections enabled to a detailed view on growth kinetics. These studies showed, oxides are the first phases occurring immediately after experimental start. As soon as reactive gas media enter the chamber, the conditions change and different reaction products, such as sulfides start to grow. A comparison of different gas environments applied, illustrated the differences in the type of reaction products. The in situ observation of high temperature material degradation by corrosion made it possible to study the contribution of phases, which are not stable at room temperature. For instance, wuestite (Fe1-xO), was frequently observed at high temperatures in humid gases on Fe with 2 wt.% and 9 wt.% chromium, but not at room temperature. The strength of the occurrence of this phase additionally explains why, despite a higher Cr content, ferritic alloys with 9 wt.% Cr in a challenging atmosphere prevent the intrinsic formation of protective layers. The in situ observations were supplemented by careful considerations of thermodynamic boundary conditions and detailed post characterization by classical metallographic analysis. Additionally, the structure and chemistry of the dominant oxide layers were evaluated using X-ray absorption near edge structure spectroscopy. The talk will give an overview about chances and challenges for studying high temperature corrosion phenomena by advanced X-ray methods. T2 - MRS Spring Meeting CT08.02.01 CY - Online Meeting DA - 18.04.2021 KW - XRD KW - Spectroscopy KW - Corrosion KW - High temperature KW - In-situ PY - 2021 AN - OPUS4-52486 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Waniek, Tassilo A1 - Braun, U. A1 - Silbernagl, Dorothee A1 - Sturm, Heinz T1 - The impact of water released from boehmite nanoparticles during curing in epoxy-based nanocomposites N2 - The enhancing effect on mechanical properties of boehmite (γ-AlOOH) nanoparticles (BNP) in epoxy-based nanocomposites on the macroscopic scale encouraged recent research to investigate the micro- and nanoscopic properties. Several studies presented different aspects relatable to an alteration of the epoxy polymer network formation by the BNP with need for further experiments to identify the mode of action. With FTIR-spectroscopic methods this study identifies interactions of the BNP with the epoxy polymer matrix during the curing process as well as in the cured nanocomposite. The data reveals that not the BNP themselves, but the water released from them strongly influences the curing process by hydrolysis of the anhydride hardener or protonation of the amine accelerator. The changes of the curing processes are discussed in detail. The changes of the curing processes enable new explanation for the changed material properties by BNP discussed in recent research like a lowered glass transition temperature region (Tg) and an interphase formation. KW - Spectroscopy KW - Aluminium oxide hydroxide KW - Glass transition temperature KW - Material chemistry KW - Nanocomposites KW - Structure-property relationship PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527202 DO - https://doi.org/10.1002/app.51006 VL - 138 IS - 39 SP - 51006 PB - Wiley Periodicals LLC CY - Hoboken AN - OPUS4-52720 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -