  Mesoporosity of Zeolite Y – 3D Quantitative Study by Image Analysis of Electron Tomograms; Gommes, Cédric  ; et alin Angewandte Chemie (International ed. in English) (2012), 51 Detailed reference viewed: 4 (0 ULg)2-Point correlation function of nanostructured materials via the grey-tone correlation function of electron tomograms: A three-dimensional structural analysis of ordered mesoporous silicaGommes, Cédric ; ; et alin Acta Materialia (2010), 58 Electron tomography is a unique technique for imaging the microstructure of materials with a nanometer resolution. The signal to noise ratio of electron tomograms is, however, often too low for a reliable ... [more ▼] Electron tomography is a unique technique for imaging the microstructure of materials with a nanometer resolution. The signal to noise ratio of electron tomograms is, however, often too low for a reliable segmentation-based image analysis. We derive a general relation between the grey-tone correlation function of the tomograms and the 2-point correlation function of the morphology, which enables to analyze quantitatively the grey-tone correlation function with a morphological model of the material. The methodology is applied to SBA-15 ordered mesoporous silica. The three-dimensional grey-tone correlation function obtained from electron tomography is analyzed in terms of a hexagonal array of Gaussian independent pores. The model enables to relate the morphology obtained from the 2-point correlation function to macroscopic characterization data of the material, notably small-angle X-ray scattering and nitrogen adsorption. [less ▲] Detailed reference viewed: 20 (0 ULg)Characterization of nanometer-scale roughness in SBA-15 mesoporous silica using image analysis of electron tomograms; Gommes, Cédric ; et alConference (2009, September) Quantization of pore corrugation in SBA-15 by image analysis of electron tomograms; Gommes, Cédric ; et alConference (2009, March) Detailed reference viewed: 1 (0 ULg)Quantitative Structural Analysis of Binary Nanocrystal Superlattices by Electron Tomography; Gommes, Cédric ; et alin Nano Letters (2009), 9 Binary nanocrystal superlattices, that is, ordered structures of two sorts of nanocolloids, hold promise for a series of functional materials with novel collective properties. Here we show that based on ... [more ▼] Binary nanocrystal superlattices, that is, ordered structures of two sorts of nanocolloids, hold promise for a series of functional materials with novel collective properties. Here we show that based on electron tomography a comprehensive, quantitative, three-dimensional characterization of these systems down to the single nanocrystal level can be achieved, which is key in understanding the emerging materials properties. On four binary lattices composed of PbSe, CdSe, and Au nanocrystals, we illustrate that ambiguous interpretations based on two-dimensional transmission electron microscopy can be prevented, nanocrystal sizes and superlattice parameters accurately determined, individual crystallographic point and plane defects studied, and the order/disorder at the top and bottom surfaces imaged. Furthermore, our results suggest that superlattice nucleation and growth occurred at the suspension/air interface and that the unit cells of some lattices are anisotropically deformed upon drying. [less ▲] Detailed reference viewed: 21 (1 ULg)Quantitative Characterization of Pore Corrugation in Ordered Mesoporous Materials Using Image Analysis of Electron TomogramsGommes, Cédric ; ; et alin Chemistry of Materials (2009), 21 Electron tomography and image analysis are combined to characterize ordered mesoporous silica SBA-15. The morphology of the mesopores with average diameter 6 nm is analyzed in terms of cylinders having ... [more ▼] Electron tomography and image analysis are combined to characterize ordered mesoporous silica SBA-15. The morphology of the mesopores with average diameter 6 nm is analyzed in terms of cylinders having variable radii and centers that are statistically centered on the points of a distorted hexagonal lattice. The variations in the mesopore centers and radii add up and result in pore wall corrugation with amplitude of 1.6 nm. The correlation length of the corrugation along the pore axis was found to be 4-5 nm. The amplitude of the corrugation compared well with the 1.9 nm thick microporous corona obtained from X-ray diffraction (XRD). In general, the present approach provides a detailed microscopic 3D model of nanostructured materials that complements macroscopic measurements such as physisorption and XRD. [less ▲] Detailed reference viewed: 19 (1 ULg) |
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