Quantitative structure determination of nanostructured materials using the atomic pair distribution function analysis
Abstract
The employed experimental method in this Ph.D. dissertation research is the atomic pair distribution function (PDF) technique specializing in high real space resolution local structure determination. The PDF is obtained via Fourier transform from powder total scattering data including the important local structural information in the diffuse scattering intensities underneath, and in-between, the Bragg peaks. Having long been used to study liquids and amorphous materials, the PDF technique has been recently successfully applied to highly crystalline materials owing to the advances in modern X-ray and neutron sources and computing power. The conventional XRD experiments probe for the presence of periodic structure which are reflected in the Bragg peaks. Local structural deviations or disorder mainly affect the diffuse scattering background. In order to have information about both long-range order and local structure disorder, a technique that takes both Bragg and diffuse scattering need to be used, such as the atomic pair distribution function (PDF) technique. This Ph.D. work introduces a PDF based methodology to quantitatively study nanostructure materials in general. The introduced methodology have been applied to a size-dependent structural study on CdSe nanoparticles (NPs). Quantitative structural information about structure, crystallinity level, core size, NP size, and inhomogeneous internal strain in the studied NPs have been obtained. This method is generally applicable to the characterization of the nano-scale solid, many of which may exhibit complex disorder and strain. The introduced methodology have been also applied on technologically important system, ultra-small CdSe NPs.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- 2008
- Bibcode:
- 2008PhDT........96M