TY - JOUR A1 - Altenburg, Simon A1 - Weber, H. A1 - Krankenhagen, Rainer T1 - Thickness determination of semitransparent solids using flash thermography and an analytical model JF - Quantitative InfraRed Thermography Journal N2 - As groundwork for thickness determination of polymeric surface protection systems for concrete, we present a method for measuring the thickness of isolated semitransparent solids using flash thermography both in transmission and reflection configuration. Since standard models do not capture semitransparency, an advanced analytical model by Salazar et al. is applied. Physical material parameters are deduced by fitting experimental data from samples of well-known thickness. Using those, the thickness of samples of the material can be obtained by fitting, as demonstrated for different semitransparent polymer materials. KW - Analytical model KW - Concrete KW - Semitransparency KW - Surface protection KW - Thermography KW - Thickness PY - 2017 DO - https://doi.org/10.1080/17686733.2017.1331655 SN - 1768-6733 SN - 2116-7176 VL - 15 IS - 1 SP - 95 EP - 105 PB - Taylor and Francis CY - Abingdon, UK AN - OPUS4-40468 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cant, D. J. H. A1 - Minelli, C. A1 - Sparnacci, K. A1 - Müller, Anja A1 - Kalbe, H. A1 - Stoger-Pollach, M. A1 - Unger, Wolfgang A1 - Werner, W. S. M. A1 - Shard, A. G. T1 - Surface-Energy Control and Characterization of Nanoparticle Coatings JF - Journal of Physical Chemistry C N2 - Accurate and reproducible measurement of the structure and properties of high-value nanoparticles is extremely important for their commercialization. A significant proportion of engineered nanoparticle systems consist of some form of nominally core-shell structure, whether by design or unintentionally. Often, these do not form an ideal core-shell structure, with typical deviations including polydispersity of the core or shell, uneven or incomplete shells, noncentral cores, and others. Such systems may be created with or without intent, and in either case an understanding of the conditions for formation of such particles is desirable. Precise determination of the structure, composition, size, and shell thickness of such particles can prove challenging without the use of a suitable range of characterization techniques. Here, the authors present two such polymer core-shell nanoparticle systems, consisting of polytetrafluoroethylene cores coated with a range of thicknesses of either polymethylmethacrylate or polystyrene. By consideration of surface energy, it is shown that these particles are expected to possess distinctly differing coating structures, with the polystyrene coating being incomplete. A comprehensive characterization of these systems is demonstrated, using a selection of complementary techniques including scanning electron microscopy, scanning transmission electron microscopy, thermogravimetric analysis, dynamic light scattering, differential centrifugal sedimentation, and X-ray photoelectron spectroscopy. By combining the results provided by these techniques, it is possible to achieve superior characterization and understanding of the particle structure than could be obtained by considering results separately. KW - Nanoparticles KW - Core-shell KW - XPS KW - Size KW - Thickness KW - Damage PY - 2020 DO - https://doi.org/10.1021/acs.jpcc.0c02161 VL - 124 IS - 20 SP - 11200 EP - 11211 PB - ACS CY - Washington DC AN - OPUS4-50899 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cant, D. J. H. A1 - Müller, Anja A1 - Clifford, C. A. A1 - Unger, Wolfgang A1 - Shard, A. G. T1 - Summary of ISO/TC 201 Technical Report 23173—Surface chemical analysis—Electron spectroscopies—Measurement of the thickness and composition of nanoparticle coatings JF - Surface and Interface Analysis N2 - ISO Technical Report 23173 describes methods by which electron spectroscopies, including X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and synchrotron techniques, can be employed to calculate the Coating thicknesses and compositions of nanoparticles. The document has been developed to review and outline the current state-of-the-art for such measurements. Such analyses of core–shell nanoparticles are common within the literature, however the methods employed are varied; the relative advantages and disadvantages of These methods, and the optimal usage of each may not be clear to the general analyst. ISO Technical Report 23173 aims to clarify the methods that are available, describe them in clear terms, exhibit examples of their use, and highlight potential issues users may face. The information provided should allow analysts of electron spectroscopy data to make clear choices regarding the appropriate analysis of electron spectroscopy data from coated nanoparticle systems and provide a basis for understanding and comparing results from different methods and systems. KW - Electron spectroscopy KW - Core-shell KW - Nanoparticles KW - ISO 23173 KW - XPS KW - Thickness KW - Composition PY - 2021 DO - https://doi.org/10.1002/sia.6987 SN - 0142-2421 VL - 53 IS - 10 SP - 893 EP - 899 PB - John Wiley & Sons Ltd AN - OPUS4-52976 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hodoroaba, Vasile-Dan A1 - Kim, K.J. A1 - Unger, Wolfgang T1 - Energy dispersive electron probe microanalysis (ED-EPMA) of elemental composition and thickness of Fe-Ni alloy films JF - Surface and interface analysis N2 - The elemental composition of thin Fe-Ni alloy films deposited on silicon substrates were determined by electron probe microanalysis with an energy dispersive spectrometer using the STRATAGem software. The work was part of ample inter-laboratory comparisons organized in the frame of CCQM/SAWG (Consultative Committee for Amount of Substance/Surface Analysis Working Group). Therefore, the evaluation of the measurement uncertainties is treated in detail. By having the mass coverage and estimating a layer density, the layer thickness could be derived. KW - Thin films KW - Fe-Ni KW - Energy dispersive electron probe microanalysis (ED-EPMA) KW - STRATAGem KW - k-values KW - Mass coverage KW - Elemental composition KW - Thickness KW - CCQM PY - 2012 DO - https://doi.org/10.1002/sia.4975 SN - 0142-2421 SN - 1096-9918 VL - 44 IS - 11-12 SP - 1459 EP - 1461 PB - Wiley CY - Chichester AN - OPUS4-27139 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Seah, M.P. A1 - Unger, Wolfgang A1 - Wang, H. A1 - Jordaan, W. A1 - Gross, Thomas A1 - Dura, J.A. A1 - Moon, D.W. A1 - Totarong, P. A1 - Krumrey, M. A1 - Hauert, R. A1 - Zhiqiang, M. T1 - Ultra-thin SiO2 on Si IX: absolute measurements of the amount of silicon oxide as a thickness of SiO2 on Si JF - Surface and interface analysis N2 - Results from a study conducted between National Metrology Institutes (NMIs) for the measurements of the absolute thicknesses of ultra-thin layers of SiO2 on Si are reported. These results are from a key comparison and associated pilot study under the auspices of the Consultative Committee for Amount of Substance. ´Amount of substance´ may be expressed in many ways, and here the measurand is the thickness of the silicon oxide layers with nominal thicknesses in the range 1.5-8 nm on Si substrates, expressed as the thickness of SiO2. Separate samples were provided to each institute in containers that limited the carbonaceous contamination to approximately < 0.3 nm. The SiO2 samples were of ultra-thin on (100) and (111) orientated wafers of Si. The measurements from the laboratories which participated in the study were conducted using ellipsometry, neutron reflectivity, X-ray photoelectron spectroscopy or X-ray reflectivity, guided by the protocol developed in an earlier pilot study. A very minor correction was made in the different samples that each laboratory received. Where appropriate, method offset values attributed to the effects of contaminations, from the earlier pilot study, were subtracted. Values for the key comparison reference values (agreed best values from a Consultative Committee study) and their associated uncertainties for these samples are then made from the weighted means and the expanded weighted standard deviations of the means of these data. These results show a dramatic improvement on previous comparisons, leading to 95% uncertainties in the range 0.09-0.27 nm, equivalent to 0.4-1.0 monolayers over the 1.5-8.0 nm nominal thickness range studied. If the sample-to-sample uncertainty is reduced from its maximum estimate to the most likely value, these uncertainties reduce to 0.05-0.25 nm or ~1.4% relative standard uncertainties. The best results achieve ~1% relative standard uncertainty. It is concluded that XPS has now been made fully traceable to the SI, for ultra-thin thermal SiO2 on Si layers, by calibration using wavelength methods in an approach that may be extended to other material systems. KW - Attenuation length KW - Calibration KW - Silicon dioxide KW - Thickness KW - Ultra-thin oxide PY - 2009 DO - https://doi.org/10.1002/sia.3045 SN - 0142-2421 SN - 1096-9918 VL - 41 IS - 5 SP - 430 EP - 439 PB - Wiley CY - Chichester AN - OPUS4-19246 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weigert, Florian A1 - Müller, A. A1 - Häusler, I. A1 - Geißler, Daniel A1 - Skroblin, D. A1 - Unger, Wolfgang A1 - Radnik, Jörg A1 - Resch-Genger, Ute T1 - Combining HR‑TEM and XPS to elucidate the core–shell structure of ultrabright CdSe/CdS semiconductor quantum dots JF - Scientific reports N2 - Controlling thickness and tightness of surface passivation shells is crucial for many applications of core–shell nanoparticles (NP). Usually, to determine shell thickness, core and core/shell particle are measured individually requiring the availability of both nanoobjects. This is often not fulfilled for functional nanomaterials such as many photoluminescent semiconductor quantum dots (QD) used for bioimaging, solid state lighting, and display technologies as the core does not show the applicationrelevant functionality like a high photoluminescence (PL) quantum yield, calling for a whole nanoobject approach. By combining high-resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS), a novel whole nanoobject approach is developed representatively for an ultrabright oleic acid-stabilized, thick shell CdSe/CdS QD with a PL quantum yield close to unity. The size of this spectroscopically assessed QD, is in the range of the information depth of usual laboratory XPS. Information on particle size and monodispersity were validated with dynamic light scattering (DLS) and small angle X-ray scattering (SAXS) and compared to data derived from optical measurements. In addition to demonstrating the potential of this novel whole nanoobject approach for determining architectures of small nanoparticles, the presented results also highlight challenges faced by different sizing and structural analysis methods and method-inherent uncertainties. KW - Photoluminescence KW - Single particle KW - Microscopy KW - Particle architecture KW - Thickness KW - SAXS KW - Shell KW - XPS KW - TEM KW - Semiconductor KW - Quantum dot KW - Photophysics KW - Quantum yield PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517911 DO - https://doi.org/10.1038/s41598-020-77530-z VL - 10 IS - 1 SP - 20712 PB - Springer Nature AN - OPUS4-51791 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -