Seminário Especial INCT/NAP/GFCx: "Investigation of silver nanoparticles with different morphologies by X-ray powder diffraction"

Dr. Oleg Prymak, 
Universidade de Essen.
Auditório Adma Jafet, IFUSP
Data: 08/04
Horário: 14h00
Investigation of silver nanoparticles with different morphologies by X-ray powder diffraction Oleg Prymak,1 Jens Helmlinger,1 Kateryna Loza,1 Marc Heggen,2 Matthias Epple1
1 Institute of Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Essen, Germany
2 Ernst Ruska-Center and Peter Grünberg Institute, Forschungszentrum Jülich GmbH, Jülich, Germany
Silver nanoparticles (Ag-NPs) are well known for their interesting optical, electronic, and biological properties. Due to their antibacterial activity, there are many silver-containing consumer products and medical devices. As their properties are not only influenced by their small size but also by their morphology, a shape-controlled synthesis of silver nanoparticles is of special interest. We have synthesized PVP-coated Ag-NPs by a modified polyol process and microwave-assisted reduction, producing well-defined morphologies (spheres, platelets, cubes,  and rods). The nanoparticles were characterized by colloidal (DLS) and microscopic methods (scanning and  transmission electron microscopy) as well by different powder diffraction methods, including grazing incidence diffraction and pole figure analysis. By Rietveld refinement, the lattice parameters and crystallite sizes were determined. A special focus of the work was the use of different stereographic projections (pole figures) to investigate the crystal growth of Ag-NPs with anisotropic shapes. 
It was demonstrated that diffraction methods are well suitable to describe not only the size, but also the shape and crystallographic orientation of metallic nanocrystals.