Filtern
Erscheinungsjahr
Dokumenttyp
- Posterpräsentation (82) (entfernen)
Referierte Publikation
- nein (82)
Schlagworte
- Nanoparticles (21)
- Electron microscopy (11)
- SEM/EDX (6)
- Thin films (6)
- TiO2 (5)
- EPMA (4)
- Electron probe microanalysis (EPMA) (4)
- Electrospray deposition (4)
- Fe-Ni (3)
- Shape (3)
Organisationseinheit der BAM
- 6 Materialchemie (29)
- 6.1 Oberflächen- und Dünnschichtanalyse (29)
- 6.7 Materialsynthese und Design (3)
- 1 Analytische Chemie; Referenzmaterialien (2)
- 1.2 Biophotonik (1)
- 1.9 Chemische und optische Sensorik (1)
- 5 Werkstofftechnik (1)
- 5.1 Mikrostruktur Design und Degradation (1)
- 6.3 Strukturanalytik (1)
A femto-second pulsed laser ablation in liquid (PLAL) procedure for the generation of titanium oxide nanoparticles (NP) is reported with the purpose of understanding morphology and structure of the newly generated NPs. Ablation duration was varied for optimization of NP generation processes between 10 and 90 min. Surface morphology of NPs as well as their size and shape (distribution) were analysed by various complementary electron microscopy techniques, i.e. SEM, TSEM and TEM. The crystalline structure of titanium oxide particles was investigated by XRD and HR-TEM. Concentration of generated titanium oxide NPs in liquid was analysed by ICP-MS. A mix of crystalline (mainly anatase), partly crystalline and amorphous spherical titanium oxide NPs can be reported having a mean size between 10 and 20 nm, which is rather independent of the laser ablation (LA) duration. A second component consisting of irregularly shaped, but crystalline titanium oxide nanostructures is co-generated in the LA water, with more pronounced occurrence at longer LA times. The provenance of this component is assigned to those spherical particles generated in suspension and passing through the converging laser beam, being hence subject to secondary irradiation effects, e. g. fragmentation.
In the present paper we show an approach of measuring large numbers of nanoparticles in a single scan TKD. TiO2 anatase nanoparticles (NP) of bipyramidal shape were deposited on standard carbon grid used for TEM. The procedure used promoted formation of NP ‘monolayer’ islands with uniform distribution of NPs on the carbon surface which allowed mapping of large number of nanoparticles in the single island.
Collection of whole map covering ~2800 nanoparticles took nearly 20 minutes. Inverse pole figure color coded map indicates that the NPs are either lying on a {101} facet (within 10° range around perfect {101} parallel to the carbon surface orientation) on the carbon film or are lying on a {100} facet (within 10° range around the perfect {100} parallel to the carbon surface orientation). Very unlikely was the NP orientation standing on a {001} face. The NPs size distribution described as equivalent circle diameter (ECD) has been also evaluated and the mean NP ECD was 59 nm with standard deviation of 15 nm, i.e. in good agreement with electron microscopy or AFM results.
This study shows high potential of the technique for crystalline NPs analysis with respect to geometrical orientation of the particles on the substrate. With known orientation, the 3D dimensional characterisation of such non-spherical NPs becomes possible from 2D projection electron micrographs. Moreover, the NP size distribution can be easily extracted. Superior accuracies down to 1-2 nm are achievable. The approach is applicable also on thin lamellae extracted from particulate (or mesoporous) layers.