Ingenieurwissenschaften und zugeordnete Tätigkeiten
Filtern
Erscheinungsjahr
- 2022 (26) (entfernen)
Dokumenttyp
- Zeitschriftenartikel (10)
- Vortrag (9)
- Posterpräsentation (3)
- Forschungsbericht (2)
- Corrigendum (1)
- Sonstiges (1)
Sprache
- Englisch (26)
Schlagworte
- Nanoparticles (9)
- Electron microscopy (5)
- SEM (5)
- VAMAS (5)
- EDS (4)
- Particle size distribution (4)
- SAXS (4)
- Thin films (4)
- AFM (3)
- HAXPES (3)
- Photocatalysis (3)
- Sample preparation (3)
- XPS (3)
- EBSD (2)
- Elemental composition (2)
- ISO/TC 202 (2)
- Inter-laboratory comparison (2)
- Microbeam Analysis (2)
- Standardisation (2)
- TEM (2)
- Automation (1)
- BadgerFilm (1)
- Core–shell particles (1)
- Correlative Imaging (1)
- Cubical shape (1)
- Dodecanethiol (1)
- EDS-TM002 (1)
- EMPIR nPSize (1)
- EPMA (Electron Probe Microanalysis) (1)
- Electrochemical catalysts (1)
- Electron Probe Microanalysis (EPMA) (1)
- Energy dispersive X-ray spectroscopy (1)
- FIB (1)
- FeNi (1)
- Film thickness (1)
- Functionalized graphene (1)
- Graphene oxide flakes (1)
- Graphene powder (1)
- Hyperspectral imaging (1)
- ISO/TC 229 (1)
- ISO/TC229 (1)
- ISOGScope (1)
- Image analysis (1)
- Iron oxide (1)
- Lifetime analysis (1)
- Ligand exchange (1)
- Magic-sized cluster (1)
- Me-TiO2 (1)
- Metal-semiconductor (1)
- Microbeam analysis (1)
- Microscopy (1)
- Mixed metal oxide (1)
- Morpho-chemical characterization (1)
- Morphology (1)
- Multi-sample analysis (1)
- Nano CRM (1)
- Nano Characterisation (1)
- Nano@BAM (1)
- Nanomaterial analysis (1)
- Nanomaterials (1)
- Nanoparticle concentration (1)
- Nanotechnologies (1)
- Non-spherical shape (1)
- One-pot synthesis (1)
- Performance check (1)
- Quantum dots (1)
- Raman (1)
- Reference materials (1)
- Reference nanoparticles (1)
- Roughness (1)
- SEM/EDS (1)
- Scanning electron microscopy (1)
- Semiconductor nanocrystals (1)
- Shape (1)
- SiGe (1)
- Size (1)
- Spectroscopic ellipsometry (1)
- Standardization (1)
- Standardized check (1)
- Surface Analysis (1)
- Surface chemistry (1)
- Surface morphology (1)
- TSEM (1)
- Test material (1)
- Thickness (1)
- Thin mesoporous films (1)
- Thiols (1)
- Titania nanoparticles (1)
- X-ray spectrometer (1)
- ZnSe (1)
- transmission mode (1)
Organisationseinheit der BAM
- 6 Materialchemie (25)
- 6.1 Oberflächen- und Dünnschichtanalyse (25)
- 1 Analytische Chemie; Referenzmaterialien (5)
- 1.2 Biophotonik (3)
- 1.0 Abteilungsleitung und andere (1)
- 1.3 Instrumentelle Analytik (1)
- 1.8 Umweltanalytik (1)
- 1.9 Chemische und optische Sensorik (1)
- 4 Material und Umwelt (1)
- 4.2 Material-Mikrobiom Wechselwirkungen (1)
Eingeladener Vortrag
- nein (9)
The liaison report from the ISO Technical Committee ISO/TC 202 'Microbeam Analysis' for the November 2022 ISO/TC 229 Nanotechnologies Plenary Meeting Nanotechnologies Liaison Coordination Group (NLCG) is provided. Essential Information such as newly published standards and projects in develeopment relevant for ISO/TC 229 resulted from the progress within the last year and additional comments on behalf of ISO/TC 202 are included in the report.
Binary photoluminescent semiconductor nanocrystals (quantum dots, QDs) are one of the best studied fluorescent nanomaterials, and their unique optoelectronic properties paved the road to many applications in (bio)nanophotonics, optoelectronics, and photovoltaics. However, concerns related to their toxic constituents like cadmium or lead and the emerging interest in greener chemistry synthesis approaches hamper their future applicability. Interesting alternatives for some applications like biosensing or bioimaging are heavy-metal-free ternary QDs like AgInS2 (AIS), CuInS2 (CIS), and quaternary QDs such as AIS-ZnS (ZAIS). In this context, we explored the effect of ligand denticity on the organic-to-aqueous phase transfer of oleylamine-stabilized ZAIS QDs with the hydrophilic ligands mercaptopropionic acid (MPA), dihydrolipoic acid (DHLA), and 3-mercapto-2,2-bis(mercaptomethyl)propanoic acid (3MPA), bearing mono-, bi-, and trialkyl thiol groups. Spectroscopic studies of the resulting water-dispersible ZAIS QDs revealed a considerable influence of ligand denticity and ligand-to-QD ratio on the spectral position and width (FWHM; full width at half-maximum) of the photoluminescence (PL) bands, the PL quantum yields (PL QY), and the PL decay kinetics. Thiol capping and phase transfer resulted in a loss in PL by at least a factor of 2. The ligand-induced PL quenching observed particularly for ligands bearing two or three thiol groups was attributed to the facilitated formation of surface-bound disulfides. The best colloidal stability under high dilution conditions was observed for 3MPA.
The progress in the activities on Microbeam Analysis under VAMAS/TWA 37 is reviewed. Particularly the liaison with the new projects within the ISO technical committee TC 202 is presented and discussed with respect to the possibility of identifying and launching related VAMAS projects/inter-laboratory comparisons. The recently started project FIB sample processing for TEM is presented. Next projects in the pipeline involving EBSD and TKD are shortly announced. The need of more promotion for the engagement of more experts from industry and academia at national, European and international level is highlighted. Also, the competition with the other technical working areas (on 'nano' or materials-related) is critically discussed.
Experience gained at BAM within the European project ISGScope on the accurate measureemnt of graphene oxide flakes by electron microscopy is presented. Particularly, factors such as the type of solvent, substrate temperature, but also proper, gentle measurement parameters and image analysis conditions towards automation are highlighted. The measurement procedures in develeopment are being prepared to launch an inter-laboratory comparison under VAMAS (TWA41) as preparatory guidance for future standardisation at ISO.
Nanoparticle Populations
(2022)
Two new projects P15 Measurement of particle size and shape distribution of bipyramidal titania including deposition from liquid suspension and P16 Measurement of (relative) number concentration of bimodal silica nanoparticles including deposition from liquid suspension have been started at VAMAS/TWA 34 under the lead of BAM. First results are presented and discussed.
Quantitative Microstructural Analysis - VAMAS TWA 37 & Liaison with ISO/TC 202 Microbeam Analysis
(2022)
The progress in activities on Microbeam Analysis under VAMAS/TWA 37 is reviewed. Particularly the liaison with the new projects within the ISO technical committee TC 202 is presented and discussed with respect to the possibility of identifying and launching related VAMAS projects. The recently started project FIB sample processing for TEM is highlighted. Need of more promotion for the engagement of more participants from industry and academia at national, European and international level is highlighted. Also, the competition with the other technical working areas (on 'nano' or materials-related) is critically discussed. Further, a short overview of the VAMAS areas of activities is given where Germany is involved. Planed regional VAMAS Workshops in Germany in 2023 are announced.
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.
One aim of the EMPIR nPSize project 17NRM04 was to develop and validate three classes of candidate reference (test) materials (RTMs), with i) well-defined non-spherical shape, ii) relatively high polydispersity index, and iii) accurate particle concentrations.
To fulfil the requirements of the project, 11 different types of materials were prepared. Following the initial assessment of the materials suitability, nPSize5_PT_UNITO, nPSize6_AC_UNITO and nPSize7_GN_CEA materials were found unsuitable for the project, due to various reasons. PT material was deemed unsuitable due to its predominantly agglomerated nature. AC material contained relatively high amount of impurities (other particle forms). GN material was found too heterogeneous in both the length and width for the purpose of the project. The remaining 8 candidate RTMs were assessed for their homogeneity and stability and used for successful delivery of the associated activities within the nPSize project.
BAM is currently building up a platform of novel nanoRMs relying on iron oxide nanoparticles of different shape, size and surface chemistry. Iron oxide was chosen as a core material because of its relevance to the material and life sciences.
As a first candidate of this series, we present cubic iron oxide nanoparticles with a nominal edge length of 8 nm. These particles were synthesized by thermal decomposition of iron oleate in high boiling organic solvents adapting well-known literature procedures. After dilution to a concentration suitable for electron microscopy (TEM and SEM) as well as for small-angle X-ray scattering (SAXS) measurements, the candidate nanoRM was bottled and assessed for homogeneity and stability by both methods following the guidelines of ISO 17034 and ISO Guide 35.
The particle sizes obtained by both STEM-in-SEM and TEM are in excellent agreement with a minimum Feret of 8.3 nm ± 0.7 nm. The aspect ratio (AR) of the iron oxide cubes were extracted from the images as the ratio of minimum Feret to Feret resulting in an AR of 1.18 for TEM to 1.25 for SEM. Alternatively, a rectangular bounding box was fitted originating from the minimum Feret and the longest distance through the particle in perpendicular direction. This led to AR values of 1.05 for TEM and 1.12 for SEM, respectively. The results confirm the almost ideal cubic shape.
Water splitting using semiconductor photo-catalysts is considered a sustainable method to produce clean hydrogen fuel. Nevertheless, H2 photo-production efficiency remains still low, although extensive research works to understand better the mechanisms of the Hydrogen Evolution Reaction (HER) and the Oxygen Evolution Reaction (OER) are being carried out. In this respect, TiO2 is a key photoactive material, usually employed with a co-catalyst deposited onto the surface to enhance charge carriers’ separation and catalyze surface charge transfer reactions. The deposition of a co-catalyst on the TiO2 nanoparticle surface represents one successful way to enhance the activity of the photocatalyst through a modification of its surface and redox properties. In this context, high-resolution scanning electron microscopy (SEM) coupled with elemental analysis by energy-dispersive X-ray spectroscopy (EDS) is fundamental for studying and understanding the effect of the nanoparticle morphology on the functional properties of shape-controlled TiO2 crystals (bipyramides, platelets, and elongated particles). Different types of metal-semiconductor combinations, TiO2 shapes and dopant metals (Ag, Pt, Au, Rh, Pd) and metal concentrations are discussed.