TY - JOUR A1 - Sachse, René A1 - Hodoroaba, Vasile-Dan A1 - Kraehnert, R. A1 - Hertwig, Andreas T1 - Multilevel effective material approximation for modeling ellipsometric measurements on complex porous thin films JF - Advanced optical technologies N2 - Catalysts are important components in chemical processes because they lower the activation energy and thus determine the rate, efficiency and selectivity of a chemical reaction. This property plays an important role in many of today’s processes, including the electrochemical splitting of water. Due to the continuous development of catalyst materials, they are becoming more complex, which makes a reliable evaluation of physicochemical properties challenging even for modern analytical measurement techniques and industrial manufacturing. We present a fast, vacuum-free and non-destructive analytical approach using multi-sample spectroscopic ellipsometry to determine relevant material parameters such as film thickness, porosity and composition of mesoporous IrOx–TiOy films. Mesoporous IrOx–TiOy films were deposited on Si wafers by sol–gel synthesis, varying the composition of the mixed oxide films between 0 and 100 wt%Ir. The ellipsometric modeling is based on an anisotropic Bruggeman effective medium approximation (a-BEMA) to determine the film thickness and volume fraction of the material and pores. The volume fraction of the material was again modeled using a Bruggeman EMA to determine the chemical composition of the materials. The ellipsometric fitting results were compared with complementary methods, such as scanning electron microscopy (SEM), electron probe microanalysis (EPMA) as well as environmental ellipsometric porosimetry (EEP). KW - Electrochemical catalysts KW - Mixed metal oxide KW - Multi-sample analysis KW - Spectroscopic ellipsometry KW - Thin mesoporous films PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551026 DO - https://doi.org/10.1515/aot-2022-0007 SN - 2192-8584 SN - 2192-8576 VL - 11 IS - 3-4 (Topical issue: Ellipsometry) SP - 137 EP - 147 PB - De Gruyter CY - Berlin AN - OPUS4-55102 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmid, Thomas A1 - Hodoroaba, Vasile-Dan T1 - Correlative Analysis by Raman and other Micro & Nanospectroscopic Imaging Techniques N2 - In the present talk the basics of the Raman spectroscopy and particularly of Raman microscopy are explained. Advantages and disadvantages of the method are highlighted through selected case studies. In the second part of the lecture examples of correlative imaging with electron, X-ray, ion and optical microscopies from micro- to the nanoscale are highlighted. T2 - Charisma School on Raman Harmonisation CY - Turin, Italy DA - 19.10.2022 KW - Raman KW - Correlative Imaging KW - Microscopy KW - Hyperspectral imaging PY - 2022 UR - https://amdgroup.inrim.it/events/vamas-sc-meeting-47/program-sc47 AN - OPUS4-56094 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hülagü, Deniz A1 - Tobias, Charlie A1 - Gojani, Ardian B. A1 - Rurack, Knut A1 - Hodoroaba, Vasile-Dan A1 - Hülagü, Deniz T1 - Towards automated scanning electron microscopy image analysis of core-shell microparticles for quasi-3D determination of the surface roughness N2 - Core-shell (CS) particles have been increasingly used for a wide range of applications due to their unique properties by merging individual characteristics of the core and the shell materials. The functionality of the designed particles is strongly influenced by their surface roughness. Quantitative evaluation of the roughness of CS microparticles is, however, a challenging task for Scanning Electron Microscopy (SEM). The SEM images contain two-dimensional (2D) information providing contour roughness data only from the projection of the particle in the horizontal plane. This study presents a practical procedure to achieve more information by tilting the sample holder, hence allowing images of different areas of a single particle to be recorded at different orientations under the same view angle. From the analysis of these images, quasi three-dimensional (3D) information is obtained. Three types of home-made particles were investigated: i) bare polystyrene (PS) particles, ii) PS particles decorated with a first magnetic iron oxide (Fe3O4) nanoparticle shell forming CS microbeads, iii) PS/Fe3O4 particles closed with a second silica (SiO2) shell forming core-shell-shell (CSS) microbeads. A series images of a single particle were taken with stepwise tilted sample holder up to 10° by an SEM with high-resolution and surface sensitive SE-InLens® mode. A reliable analysis tool has been developed by a script in Python to analyze SEM images automatically and to evaluate profile roughness quantitatively, for individual core-shell microparticles. Image analysis consists of segmentation of the images, identifying contour and the centre of the particle, and extracting the root mean squared roughness value (RMS-RQ) of the contour profile from the particle projection within a few seconds. The variation in roughness from batch-to-batch was determined with the purpose to set the method as a routine quality check procedure. Flow cytometry measurements provided complementary data. Measurement uncertainties associated to various particle orientations were also estimated. T2 - ICASS 5th International Conference on Applied Surface Science CY - Palma, Mallorca, Spain DA - 25.04.2022 KW - Core-shell particles KW - Image analysis KW - Roughness KW - Scanning electron microscopy PY - 2022 AN - OPUS4-54774 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sachse, René A1 - Moor, Maëlle A1 - Kraehnert, Ralph A1 - Hodoroaba, Vasile-Dan A1 - Hertwig, Andreas T1 - Ellipsometry-based approach for the characterization of mesoporous thin films for H2 technologies JF - Advanced Engineering Materials N2 - Porous thin layer materials are gaining importance in different fields of technology and pose a challenge to the accurate determination of materials properties important for their function. In this work, we demonstrate a hybrid measurement technique using ellipsometry together with other independent methods for validation. Ellipsometry provides information about the porosity of different mesoporous films (PtRuNP/OMC = 45%; IrOx = 46%) as well as about the pore size (pore radius of ca. 5 nm for PtRuNP/OMC). In addition, the electronic structure of a material, such as intraband transitions of a mesoporous IrOx film, can be identified, which can be used to better understand the mechanisms of chemical processes. In addition, we show that ellipsometry can be used as a scalable imaging and visualization method for quality assurance in production. These require accurate and traceable measurements, with reference materials playing an important role that include porosity and other related properties. We show that our novel analytical methods are useful for improving analytical work in this entire field. KW - Porous materials KW - Electrolysis KW - Spectroscopic ellipsometry KW - Hybrid metrology measurement KW - Electron microscopy PY - 2021 DO - https://doi.org/10.1002/adem.202101320 SP - 1 EP - 17 PB - Wiley-VCH AN - OPUS4-53960 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hülagü, Deniz A1 - Tobias, Charlie A1 - Climent Terol, Estela A1 - Gojani, Ardian A1 - Rurack, Knut A1 - Hodoroaba, Vasile-Dan T1 - Generalized Analysis Approach of the Profile Roughness by Electron Microscopy with the Example of Hierarchically Grown Polystyrene–Iron Oxide–Silica Core–Shell–Shell Particles JF - Advanced Engineering Materials N2 - The roughness as a property of core–shell (CS) microparticles plays a key role in their functionality. Quantitative evaluation of the roughness of CS microparticles is, however, a challenging task with approaches using electron microscopy images being scarce and showing pronounced differences in terms of methodology and results. This work presents a generalized method for the reliable roughness determination of nonplanar specimens such as CS particles from electron microscopic images, the method being robust and reproducible with a high accuracy. It involves a self-written software package (Python) that analyzes the recorded images, extracts corresponding data, and calculates the roughness based on the deviation of the identified contour. Images of single particles are taken by a dual mode scanning electron microscopy (SEM) setup which permits imaging of the same field-of-view of the sample with high resolution and surface sensitive in SE InLens mode as well as in transmission mode (TSEM). Herein, a new type of polystyrene core–iron oxide shell–silica shell particles is developed to serve as a set of lower micrometer-sized study objects with different surface roughness; the analysis of their images by the semiautomatic workflow is demonstrating that the particles’ profile roughness can be quantitatively obtained. KW - Core–shell particles KW - Image analysis KW - Nanoparticles KW - Roughness KW - SEM KW - transmission mode PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542576 DO - https://doi.org/10.1002/adem.202101344 SP - 1 EP - 9 PB - Wiley-VCH AN - OPUS4-54257 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan A1 - Hörenz, Christoph A1 - Pellegrino, F. A1 - Maurino, V. A1 - Durande, B. A1 - Taché, O. T1 - Nanoparticle size, shape, and concentration measurement at once – two VAMAS pre-standardization projects ready to start N2 - A case study on the TEM analysis of the size and shape distribution of TiO2 bipyramidal nanoparticles prepared on TEM grids was included in the recently published ISO standard ISO 21363. It was agreed to organize at a later stage a second inter-lab comparison with the nanoparticles distributed to the participants as a liquid suspension. Protocols for uniform nanoparticle deposition on suited supports developed and optimized within the EMPIR nPSize project are also prepared to be distributed. For this, we have chosen the VAMAS platform (www.vamas.org) which offers an excellent international infrastructure of laboratories with high competence in nanoparticle measurement. The VAMAS technical working area dedicated to nanoparticle measurement is TWA 34 ‘Nanoparticle populations’. For this type of nanoparticles, the size and shape distributions are the primary parameters to be reported. Due to the good deposition protocols developed, an automated image analysis is enabled (in contrast to the manual analysis of irregular TiO2 nanoparticles. In parallel with the TiO2 nanoparticle exercise, two spherical SiO2 nanoparticle samples with bi-modal size distributions (nominal relative number concentrations of 1:1 and 10:1) are prepared for a second VAMAS inter-lab comparison. Here, the nanoparticle concentration is the primary parameter to be measured. For the imaging methods it is targeted to measure the relative nanoparticle concentrations of the two modes. For the absolute nanoparticle concentration to be measured by imaging methods it is necessary to control the volume of the liquid suspension deposited on the substrate and to obtain such a homogeneous nanoparticle deposition on the substrate which allows to count (or extrapolate) all the deposited particles. T2 - Microscopy and Microanalysis 2021 CY - Online meeting DA - 01.08.2021 KW - Nanoparticles KW - Electron microscopy KW - VAMAS KW - Inter-laboratory comparison KW - TiO2 KW - SiO2 PY - 2021 AN - OPUS4-53065 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hülagü, Deniz A1 - Tobias, Charlie A1 - Gojani, Ardian A1 - Rurack, Knut A1 - Hodoroaba, Vasile-Dan T1 - Analysis of the profile roughness of core-shell microparticles by electron microscopy JF - Microscopy and Microanalysis N2 - A particle roughness analysis tool, based on electron microscopy images (SEM and TEM). The influence of various parameters on the calculated roughness was also investigated: the setting of the proper threshold, accelerating voltage, etc. The samples were gradually tilted to extend imaging information of more than only one projection. Furthermore, the measurement uncertainty of the profile roughness of particles associated to various orientations was estimated. KW - Core-shell particles KW - Electron microscopy KW - Image processing KW - MamaLoCa KW - Particle Characterization KW - Roughness PY - 2021 DO - https://doi.org/10.1017/S1431927621007285 VL - 27 IS - Suppl. 1 SP - 2002 EP - 2004 PB - Cambridge University Press AN - OPUS4-53123 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rühle, Bastian A1 - Krumrey, Julian Frederic A1 - Hodoroaba, Vasile-Dan T1 - Workflow towards automated segmentation of agglomerated, non‑spherical particles from electron microscopy images using artificial neural networks JF - Scientific reports N2 - We present a workflow for obtaining fully trained artificial neural networks that can perform automatic particle segmentations of agglomerated, non-spherical nanoparticles from scanning electron microscopy images “from scratch”, without the need for large training data sets of manually annotated images. The whole process only requires about 15 minutes of hands-on time by a user and can typically be finished within less than 12 hours when training on a single graphics card (GPU). After training, SEM image analysis can be carried out by the artificial neural network within seconds. This is achieved by using unsupervised learning for most of the training dataset generation, making heavy use of generative adversarial networks and especially unpaired image-to-image translation via cycle-consistent adversarial networks. We compare the segmentation masks obtained with our suggested workflow qualitatively and quantitatively to state-of-the-art methods using various metrics. Finally, we used the segmentation masks for automatically extracting particle size distributions from the SEM images of TiO2 particles, which were in excellent agreement with particle size distributions obtained manually but could be obtained in a fraction of the time. KW - Electron microscopy KW - Neural networks KW - Artificial intelligence KW - Image segmentation KW - Automated image analysis PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522454 DO - https://doi.org/10.1038/s41598-021-84287-6 VL - 11 IS - 1 SP - 4942 PB - Springer Nature AN - OPUS4-52245 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Rühle, Bastian A1 - Krumrey, Julian Frederic A1 - Hodoroaba, Vasile-Dan T1 - Dataset accompanying the publication "Workflow towards automated segmentation of agglomerated, non-spherical particles from electron microscopy images using artificial neural networks" N2 - This dataset accompanies the following publication, first published in Scientific Reports (www.nature.com/articles/s41598-021-84287-6): B. Ruehle, J. Krumrey, V.-D. Hodoroaba, Scientific Reports, Workflow towards Automated Segmentation of Agglomerated, Non-Spherical Particles from Electron Microscopy Images using Artificial Neural Networks, DOI: 10.1038/s41598-021-84287-6 It contains electron microscopy micrographs of TiO2 particles, the corresponding segmentation masks, and their classifications into different categories depending on their visibility/occlusion. Please refer to the publication and its supporting information for more details on the acquisition and contents of the dataset, as well as the GitHub repository at https://github.com/BAMresearch/automatic-sem-image-segmentation KW - Electron microscopy KW - Neural networks KW - Image segmentation KW - Automated image analysis PY - 2021 DO - https://doi.org/10.5281/zenodo.4563942 PB - Zenodo CY - Geneva AN - OPUS4-52246 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Marcoulaki, E. A1 - M. López de Ipina, J. A1 - Vercauteren, S. A1 - Bouillard, J. A1 - Himly, M. A1 - Lynch, I. A1 - Witters, H. A1 - Shandilya, N. A1 - van Duuren-Stuurman, B. A1 - Kunz, Valentin A1 - Unger, Wolfgang A1 - Hodoroaba, Vasile-Dan A1 - Bard, D. A1 - Evans, G. A1 - Jensen, K. A. A1 - Pilou, M. A1 - Viitanen, A.-K. A1 - Bochon, A. A1 - Duschl, A. A1 - Geppert, M. A1 - Persson, K. A1 - Votgreave, I. A1 - Niga, P. A1 - Gini, M. A1 - Eleftheriadis, K. A1 - Scalbi, S. A1 - Caillard, B. A1 - Arevalillo, A. A1 - Frejafon, E. A1 - Aguerre-Chariol, O. A1 - Dulio, V. T1 - Blueprint for a self-sustained European Centre for service provision in safe and sustainable innovation for nanotechnology JF - Nanoimpact N2 - The coming years are expected to bring rapid changes in the nanotechnology regulatory landscape, with the establishment of a new framework for nano-risk governance, in silico approaches for characterisation and Risk assessment of nanomaterials, and novel procedures for the early identification and management of nanomaterial risks. In this context, Safe(r)-by-Design (SbD) emerges as a powerful preventive approach to support the development of safe and sustainable (SSbD) nanotechnology-based products and processes throughout the life cycle. This paper summarises the work undertaken to develop a blueprint for the deployment and operation of a permanent European Centre of collaborating laboratories and research organisations supporting safe Innovation in nanotechnologies. The proposed entity, referred to as “the Centre”, will establish a ‘one-stop shop’ for nanosafety-related services and a central contact point for addressing stakeholder questions about nanosafety. Its operation will rely on significant business, legal and market knowledge, as well as other tools developed and acquired through the EU-funded EC4SafeNano project and subsequent ongoing activities. The proposed blueprint adopts a demand-driven service update scheme to allow the necessary vigilance and flexibility to identify opportunities and adjust its activities and services in the rapidly evolving regulatory and nano risk governance landscape. The proposed Centre will play a major role as a conduit to transfer scientific knowledge between the Research and commercial laboratories or consultants able to provide high quality nanosafety services, and the end-users of such services (e.g., industry, SMEs, consultancy firms, and regulatory authorities). The Centre will harmonise service provision, and bring novel risk assessment and management approaches, e.g. in silico methodologies, closer to practice, notably through SbD/SSbD, and decisively support safe and sustainable innovation of industrial production in the nanotechnology industry according to the European Chemicals Strategy for Sustainability. KW - Nanotechnology KW - European Centre KW - Nano-safety KW - Nanomaterials KW - analytical service PY - 2021 DO - https://doi.org/10.1016/j.impact.2021.100337 VL - 23 SP - 100337 PB - Elsevier B.V. AN - OPUS4-52942 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wurzler, Nina A1 - Schütter, Jan David A1 - Wagner, R. A1 - Dimper, Matthias A1 - Hodoroaba, Vasile-Dan A1 - Lützenkirchen-Hecht, D. A1 - Özcan Sandikcioglu, Özlem T1 - Preconditioning of AISI 304 stainless steel surfaces in the presence of flavins—Part II: Effect on biofilm formation and microbially influenced corrosion processes JF - Materials and Corrosion N2 - Biofilm formation and microbially influenced corrosion of the iron-reducing microorganism Shewanella putrefaciens were investigated on stainless steel surfaces preconditioned in the absence and presence of flavin molecules by means of XANES (X-ray absorption near-edge structure) analysis and electrochemical methods. The results indicate that biofilm formation was promoted on samples preconditioned in electrolytes containing minute amounts of flavins. On the basis of the XANES results, the corrosion processes are controlled by the iron-rich outer layer of the passive film. Biofilm formation resulted in a cathodic shift of the open circuit potential and a protective effect in terms of pitting corrosion. The samples preconditioned in the absence of flavins have shown delayed pitting and the samples preconditioned in the presence of flavins did not show any pitting in a window of −0.3- to +0.0-V overpotential in the bacterial medium. The results indicate that changes in the passive film chemistry induced by the presence of minute amounts of flavins during a mild anodic polarization can change the susceptibility of stainless steel surfaces to microbially influenced corrosion. KW - Biofilms KW - XANES KW - Microbially influenced corrosion (MIC) PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528130 DO - https://doi.org/10.1002/maco.202012192 VL - 72 IS - 6 SP - 983 EP - 994 PB - Wiley AN - OPUS4-52813 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bennet, Francesca A1 - Burr, L. A1 - Schmid, D. A1 - Hodoroaba, Vasile-Dan T1 - Towards a method for quantitative evaluation of nanoparticle from suspensions via microarray printing and SEM analysis JF - Journal of Physics: Conference Series N2 - As part of the development of a library of accurate and efficient methods for measurement of nanoparticle properties, we develop and optimize a method for the efficient analysis of nanoparticle size distribution from suspensions via microprinting and digital analysis of electron microscopy (SEM and TEM) images, with the ultimate aim of automated quantitative concentration analysis (calculated from drop volume). A series of different nanoparticle suspensions (gold, latex, and SiO2 in varying sizes and concentrations) were printed onto TEM grids in a 4 x 4 array in the concentration range 7x10^8 to 1x10^11 nanoparticles/mL and imaged with SEM. Concentrations and printing conditions (temperature, relative humidity) were varied in order to minimize the coffee-ring effect. KW - Nanoparticles KW - Particle size distribution KW - Electron microscopy KW - Microarray printing KW - Sample preparation KW - Nanoparticle concentration PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528455 DO - https://doi.org/10.1088/1742-6596/1953/1/012002 VL - 1953 SP - 012002 PB - IOP Publishing AN - OPUS4-52845 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gojani, Ardian A1 - Tobias, Charlie A1 - Hülagü, Deniz A1 - Rurack, Knut A1 - Hodoroaba, Vasile-Dan T1 - Toward determination of the surface roughness of particles from a SEM image JF - Microscopy and microanalysis N2 - In this communication, we address the issue of roughness measurement by investigating if the grayscale values from SEM images can be used for surface roughness determination of spherical particles. KW - MamaLoCA KW - Core-shell particles KW - Electron microscopy KW - Image processing KW - Particle characterisation KW - Roughness PY - 2021 DO - https://doi.org/10.1017/S1431927621011375 SN - 1431-9276 SN - 1435-8115 VL - 27 IS - Suplement S1 SP - 3302 EP - 3305 PB - Cambridge University Press CY - New York, NY AN - OPUS4-53283 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hülagü, Deniz A1 - Tobias, Charlie A1 - Gojani, Ardian B. A1 - Rurack, Knut A1 - Hodoroaba, Vasile-Dan T1 - From 2D and Single Particle to 3D and Batch Analysis as a Routine Quality Check Procedure for the Morphological Characterization of Core-Shell Microparticles JF - Microscopy and Microanalysis N2 - CS particles show unique properties by merging individual characteristics of the core and the shell materials. An alteration particularly in their surface roughness affects the final performance of the particles in the targeted application. Quantitative evaluation of the roughness of CS microparticles is, however, a challenging task employing microscopic techniques being scarce and showing large differences in terms of methodology and results. In our previous work, we have reported a systematic study with a reliable analysis tool, which evaluates profile roughness quantitatively, for individual core-shell microparticles using electron microscopy (EM) images of both types, Scanning Electron Microscopy (SEM) and transmission mode SEM (or TSEM). The SEM images contain two-dimensional (2D) information, therefore, provide profile roughness data only from the projection in the horizontal plane (in other words, from the “belly”) of a spherical particle. The present study offers a practical procedure to give access to more information by tilting the sample holder and hence allowing images of a single particle to be recorded at different orientations under the same view angle. From the analysis of these images, extended information on surface roughness of the particle can be extracted. Thus, instead of obtaining 2D information from a single SEM image, three-dimensional (3D) information is obtained from 2D projections recorded at different particle orientations. T2 - Microscopy and Microanalysis 2022 CY - Oregon, Portland, USA DA - 31.07.2022 KW - Core-shell particles KW - Image processing KW - Roughness KW - Scanning electron microscopy KW - Tilting PY - 2022 DO - https://doi.org/10.1017/S1431927622002094 SN - 1431-9276 VL - 28 IS - S1 SP - 332 EP - 334 PB - Cambridge University Press AN - OPUS4-55373 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - Standardized workflow for checking the performance of an EDS X-ray spectrometer at a Scanning Electron Microscope N2 - For test laboratories operating under accreditation schemes like ISO/IEC 17025 (ISO/IEC 17025), as the international reference for testing and calibration laboratories wanting to demonstrate their capacity to deliver reliable results, a periodical control of the critical instrumental parameters of an Energy-Dispersive X-ray Spectrometer (EDS) is required. This periodical check of an EDS is specified with exact procedures and materials in the ISO 15632:2021 ”Microbeam Analysis – Selected instrumental performance parameters for the specification and checking of energy-dispersive X-ray spectrometers for use in electron probe microanalysis” (ISO 15632). The EDS check can be simplified to the acquisition of only one 10 kV spectrum from a dedicated test material, EDS-TM002, which is made available by BAM since 2009 (https://webshop.bam.de/webshop_en/). The optional BAM software “EDX spectrometer check” is destined to automatically evaluate this spectrum and determine the performance of the EDS in terms of energy resolution and calibration, as well as possible alteration of low-energy efficiency due to detector contamination. Nearly 200 laboratories have the EDS-TM and associated software package in use. Practical examples based on various types of artifacts occurred in the EDS spectra and a long-term (>10 years) meticulous observation of the own spectrometers will be discussed. Different types of EDS spectrometers are considered, e.g. Si(Li) and SDD, of various window types (AP, the recent one Si3N4 or even windowless), and with different front contact layers (Au and Ni) (Hodoroaba and Procop, 2014). Evaluation of other parameters or effects such as the deadtime at different count rates or pileup effects is also explained with examples. T2 - Workshop "Automated Mineralogy" @ GEOANALYSIS 2022 CY - Freiberg, Germany DA - 06.08.2022 KW - EDS KW - X-ray spectrometer KW - Performance check KW - Test material KW - Standardized check KW - EDS-TM002 PY - 2022 UR - https://geoanalysis2021.de/en/workshops/automated-mineralogy AN - OPUS4-55460 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - Nanoparticles and films characterization: Electron microscopy and related techniques N2 - Scanning Electron Microscopy (SEM) represents the mostly widespread method available in analytical laboratories dedicated to the characterization of physical properties such as morphology of various solid materials from ‘micro-’ down to the nanometre scale. The use of secondary electrons excited by a sharply, nm-focussed primary electron beam enables at any modern SEM to image objects with high in-depth and lateral sensitivity, i.e. with high spatial resolution. Hence, e. g. nanoparticles (NPs) are able to be easily characterized with respect to their individual size and shape, but also to the morphology of their surface. By preparing the nano-objects on thin membranes as electron transparent samples it is possible to perform electron microscopy in the transmission mode (TEM and TSEM). The corresponding transmission (i.e. mass-thickness) contrast reveals in-depth information, but is also well suited for dimensional measurements in the 2D projection image. Both the surface sensitive mode and the transmission one are meanwhile available at any modern SEM. If an X-ray spectrometer is attached to an electron microscope, it is possible to analyse the characteristic X-rays induced by electron bombardment. Most electron microscopes have attached an energy dispersive X-ray spectrometer (EDX) so that EDX elemental maps can be carried out. Recent technological developments of high throughput EDS detectors and their advantages regarding high-resolution X-ray analysis down to the nm range are reviewed. High-resolution micrographs (SEM, TSEM, TEM) and corresponding X-ray elemental maps on various representative nanoparticles, but also layered samples prepared in cross-section, will be presented and discussed. The importance of selecting the best suited analysis conditions will be highlighted. Also other, often challenging, topics such as sample preparation and image data processing will be critically addressed by practical examples. Further analytical techniques able to be employed at an electron microscope, like cathodoluminescence (CL) or micro-X-ray fluorescence (µXRF) will be briefly surveyed. T2 - Nanoscience Meets Metrology - Synthesis, Characterization, Testing and Applications of Validated Nanoparticles - International Summer School CY - Turin, Italy DA - 04.09.2016 KW - Nanoparticles KW - Electron microscopy KW - High-resolution KW - Thin films KW - X-ray spectroscopy PY - 2016 UR - http://www.setnanometro.eu/events/ AN - OPUS4-37325 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ortel, Erik A1 - Häusler, Ines A1 - Österle, Werner A1 - Narbey, S. A1 - Oswald, F. A1 - Andersen, I. H. A1 - Holzweber, Markus A1 - Unger, Wolfgang A1 - Hodoroaba, Vasile-Dan T1 - In-depth structural and chemical characterization of engineered TiO2 films JF - Surface and Interface Analysis N2 - Analytical routines for a comprehensive in-depth morphological, structural, and chemical characterization of functionalized TiO2 films by using different state-of-the-art analytical techniques are presented and discussed with the main objective to identify potential reference TiO2 coating parameters able to be certified at a later stage. TiO2 films fabricated by two different synthetic procedures as representative for two main large-scale applications were selected: (i) pulsed d.c. magnetron sputtering for photocatalytic applications and (ii) screen printing from preformed anatase nanoparticles. The screen-printed films were further loaded with a sensitizing dye for application as a dye-sensitized solar cell. Film properties such as microstructure and crystallographic texture of pulsed d.c. magnetron sputtering synthesized films were systematically studied by means of scanning nanobeam electron diffraction in a transmission electron microscope and the surface and inner morphology by scanning electron microscopy. The dye distribution over the depth of screen-printed TiO2 layers was analyzed before and after dye-loading by means of energy dispersive X-ray spectroscopy at scanning electronmicroscope, Auger electron spectroscopy and time-of-flight secondary ion mass spectrometry. The long-term goal of the present study is the improvement of quality of the TiO2 film parameters as measured by using different types of reference TiO2 coatings having specific parameters certified. T2 - 16th European Conference on Applications of Surface and Interface Analysis ECASIA'15 CY - Granada, Spain DA - 28.09.2015 KW - Mapping KW - Line scan KW - Depth profiling KW - TiO2 films KW - Crystallinity KW - Ru dye sensitizer PY - 2016 DO - https://doi.org/10.1002/sia.5966 SN - 0142-2421 SN - 1096-9918 VL - 48 SP - 664 EP - 669 PB - John Wiley & Sons, Ltd. AN - OPUS4-36791 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Babick, F. A1 - Mielke, Johannes A1 - Wohlleben, W. A1 - Weigel, St. A1 - Hodoroaba, Vasile-Dan T1 - How reliably can a material be classified as a nanomaterial? Available particle-sizing techniques at work JF - Journal of Nanoparticle Research N2 - Currently established and projected regulatory frameworks require the classification of materials (whether nano or non-nano) as specified by respective definitions, most of which are based on the size of the constituent particles. This brings up the question if currently available techniques for particle size determination are capable of reliably classifying materials that potentially fall under these definitions. In this study, a wide variety of characterisation techniques, including counting, fractionating, and spectroscopic techniques, has been applied to the same set of materials under harmonised conditions. The selected materials comprised well-defined Quality control materials (spherical, monodisperse) as well as industrial materials of complex shapes and considerable polydispersity. As a result, each technique could be evaluated with respect to the determination of the number-weighted median size. Recommendations on the most appropriate and efficient use of techniques for different types of material are given. KW - Nanomaterial classification KW - Nanoparticle KW - Number-weighted median size KW - Tiered KW - Particle size analysis KW - Nanometrology KW - Characterisation techniques PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-367922 UR - http://link.springer.com/article/10.1007/s11051-016-3461-7 DO - https://doi.org/10.1007/s11051-016-3461-7 SN - 1388-0764 SN - 1572-896X VL - 18 IS - 6 SP - Article 158, 1 EP - 40 PB - Springer AN - OPUS4-36792 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ortel, Erik A1 - Hertwig, Andreas A1 - Berger, D. A1 - Esposito, P. A1 - Rossi, A. M. A1 - Kraehnert, R. A1 - Hodoroaba, Vasile-Dan T1 - New approach on quantification of porosity of thin films via electron-excited X‑ray spectra JF - Analytical Chemistry N2 - One of the crucial characteristics of functionalized thin films is their porosity (i.e., the ratio between the pore volume and the volume of the whole film). Due to the very low amount of material per coated area corresponding to thin films, it is a challenge for analytics to measure the film porosity. In this work, we present an Approach to determine the porosity of thin films by means of electron probe microanalysis (EPMA) either by wavelength-dispersive X-ray spectrometry (WDX) or by energy-dispersive X-ray spectrometry (EDX) with a scanning electron microscope (SEM). The procedure is based on the calculation of the film mass deposition from electron-excited X-ray spectra. The mass deposition is converted into film density by division of measured film thickness. Finally, the film porosity is calculated from the measured film density and the density of bulk, nonporous film material. The general applicability of the procedure to determine the porosity is demonstrated on thin templated mesoporous TiO₂ films, dip-coated on silicon wafer, with controlled porosity in the range of 15 to 50%. The high accuracy of the mass deposition as determined from X-ray spectra was validated with independent methods (ICP-OES and weighing). Furthermore, for the validation of the porosity results, ellipsometry, interference fringes method (IFM), and focused ion beam (FIB) cross sectioning were employed as independent techniques. Hence, the approach proposed in the present study is proven to be suited as a new analytical tool for accurate and relatively fast determination of the porosity of thin films. KW - Porosity KW - X-rays KW - EDX KW - Thin film KW - TiO2 KW - Density KW - Mass deposition KW - STRATAGem PY - 2016 UR - http://pubs.acs.org/doi/abs/10.1021/acs.analchem.6b00847 DO - https://doi.org/10.1021/acs.analchem.6b00847 VL - 88 IS - 14 SP - 7083 EP - 7090 PB - ACS Publications CY - 1155 Sixteenth Street N.W., Washington, DC 20036 AN - OPUS4-36911 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Holzweber, Markus A1 - Unger, Wolfgang A1 - Hodoroaba, Vasile-Dan T1 - Ionic liquids as a reference material candidate for the quick performance check of energy dispersive X-ray spectrometers for the low energy range below 1 keV JF - Analytical Chemistry N2 - Ionic liquids (ILs) are proposed as simple and efficient test materials to evaluate the performance of energy dispersive X-ray spectrometers (EDS) in the low energy range below 1 keV. By only one measurement, C Kα, N Kα, O Kα, and F Kα X-ray lines can be excited. Additionally, the S Kα line at 2.3 keV and, particularly, the S L series at 149 eV complete the picture with X-ray lines offered by the selected ILs. The well-known (certifiable) elemental composition of the ILs selected in the present study can be used to check the accuracy of results produced with the available EDS quantification routines in the low energy range, simultaneously, for several low atomic number elements. A comparison with other reference materials in use for testing the performance of EDS in the low energy range is included. KW - Ionic liquids KW - EDX KW - CRM KW - Reference material KW - Low energy KW - X-rays PY - 2016 UR - http://pubs.acs.org/doi/abs/10.1021/acs.analchem.6b01444 DO - https://doi.org/10.1021/acs.analchem.6b01444 SN - 0003-2700 SN - 1520-6882 VL - 88 IS - 14 SP - 6967 EP - 6970 PB - ACS Publications CY - 1155 Sixteenth Street N.W., Washington, DC 20036 AN - OPUS4-36912 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -