Diffraction Studies of Nanocrystals: Theory and Experiment

Pałosz, B.; Grzanka, Ewa; Gierlotka, S.; Stelmakh, S.; Pielaszek, Roman; Bismayer, U.; Neuefeind, Jöerg C.; Weber, Hans Peter; Pałosz, W.

doi:10.12693/aphyspola.102.57

Cited by 42 publications

(44 citation statements)

References 32 publications

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“…However, based on crystallographic assumptions, the applicability of such method to small nanoparticles is questionable and likely to be semiquantitative at best. Palosz et al [60] have shown that the conventional tools developed for elaboration of powder diffraction data are not directly applicable to nanocrystals. [60] The atomic PDF, G(r), is based on the total scattering experiment where both Bragg and diffuse scattering signals are utilised to obtain structural information at different atomic scales.…”

Section: Resultsmentioning

confidence: 99%

“…Palosz et al [60] have shown that the conventional tools developed for elaboration of powder diffraction data are not directly applicable to nanocrystals. [60] The atomic PDF, G(r), is based on the total scattering experiment where both Bragg and diffuse scattering signals are utilised to obtain structural information at different atomic scales. Structural information can be extracted from the measured PDFs data using a fullprofile real-space local structure refinement method, [58] using the program PDFgui.…”

Section: Resultsmentioning

confidence: 99%

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Total scattering atomic pair distribution function: new methodology for nanostructure determination

Masadeh

2016

Journal of Experimental Nanoscience

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The conventional X-ray diffraction (XRD) methods probe for the presence of long-range order towards a solution of the average crystal structure. Experimentally, structural information about longrange, periodic atomic ordering is reflected in the Bragg scattering while local atomic structural deviations from the average structure mainly affect the diffuse scattering intensities. In order to obtain structural information about both average and local atomic structures, a technique that takes in account both Bragg and diffuse scattering needs to be employed, such as the total scattering atomic pair distribution function (PDF) technique. This article introduces a PDF-based methodology that can be applied to extract precise structural information about nanoparticles such as the size of the crystalline core region, the degree of crystallinity, the atomic structure of the core region, local bonding, and the degree of the internal disorder, as a function of the nanoparticle diameter. This article sheds light on a new PDF-based methodology that can yield precise quantitative structural information about small nanocrystals from XRD data, and also describes the essential aspects of this proposed methodology as well as its great potential. This method is generally applicable to the characterisation of the nanoscale solid, many of which may exhibit complex disordered structure.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Total scattering atomic pair distribution function: new methodology for nanostructure determination

Masadeh

2016

Journal of Experimental Nanoscience

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“…For these smallest crystals it was difficult to assess concentration of dislocations. Dislocation concentration was very low, less than the sensitivity limit, 10 13 m −2 . The full width at half maximum ͑FWHM͒ of experimental line profiles for sample A are plotted in Fig.…”

Section: Resultsmentioning

confidence: 81%

“…These features can be used for identification and evaluation of the surface structure: ͑i͒ relative difference between alp values measured at low and large Q is a measure of thickness of the shell and strain at the grain surface; ͑ii͒ the alp values measured at very large Q tend to approach the value of the lattice parameter in the grain core; ͑iii͒ "jumps" of alp values calculated for individual reflections are caused by anisotropy of the grain shapes. [9][10][11] The concept of alp has recently been used to analyze strains in nanocrystalline SiC powders. …”

Section: B Alp Analysismentioning

confidence: 99%

“…7 Recently Palosz and coworkers have developed a methodology of elaborating powder diffractograms of nanosize materials in terms of two distinct phases-the core and the shell components. [9][10][11] In this model, the apparent lattice parameter model alp, both phases are ordered and the core structure is assumed to be similar to that of a large crystal. The methodology, discussed in details in previous publications, is based on a comparison of experimental results with those obtained theoretically for different models of nanosize grains.…”

Section: Introductionmentioning

confidence: 99%

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Microstructure of nanocrystalline diamond powders studied by powder diffractometry

Pałosz

Grzanka

Pantea³

et al. 2005

Journal of Applied Physics

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High resolution x-ray diffraction peaks of diamond nanosize powders of nominal sizes ranging from 5 to 250nm were analyzed and provided information on grain structure, average size of crystallites, and concentration of dislocations. Selected samples were heat treated at 1670K at pressures 2.0 and 5.5GPa or had surface modified by outgassing, heat treatment at vacuum conditions, and by controlled adsorption of gases. The apparent lattice parameter method was applied to characterize the structure of a shell-core model of nanosize particles. The multiple whole profile fitting provided information on crystallite sizes and density of dislocations. Population of dislocations increased with applied pressure, while strain and interplanar distances in the surface layers decreased. Adsorption of foreign gases on the grain surface modified the structure of the surface layers but did not affect dislocations near the center of the grains.

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Non‐aqueous Synthesis of Isotropic and Anisotropic Actinide Oxide Nanocrystals

Hudry

Apostolidis

Walter

et al. 2012

Chemistry A European J

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Nano is everywhere but actinides are the forgotten elements of the nanoworld! Isotropic faceted uranium oxide nanodots and anisotropic thorium oxide nanorods were synthesized. These nano‐objects are very well crystallized and monodisperse. The characteristics of the actinide oxide nanocrystals can be controlled by tuning the reactivity of the starting actinide precursors. Such results pave the way for the synthesis of transuranium‐based nano‐objects.

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Diffraction Studies of Nanocrystals: Theory and Experiment

Cited by 42 publications

References 32 publications

Total scattering atomic pair distribution function: new methodology for nanostructure determination

Total scattering atomic pair distribution function: new methodology for nanostructure determination

Microstructure of nanocrystalline diamond powders studied by powder diffractometry

Non‐aqueous Synthesis of Isotropic and Anisotropic Actinide Oxide Nanocrystals

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