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Plasmonic resonance in diagnostics of processes for formation of nanosized silver

Galina P. Aleksandrova ,  Ludmila A. Grishchenko ,  Svetlana A. Medvedeva ,  Boris G. Sukhov ,  Boris A. Trofimov 

Irkutsk Instutute of Chemistry (IRICH), 1 Favorsky Street, Irkutsk 664033, Russian Federation

Abstract

Distinctive optical properties of nanosized metals make them very promising for the development of new materials which stimulates search for new methods of their synthesis. Their particular features are connected with possibility to regulate their sizes and therefore their optical characteristics.


The approach to synthesis of nanosized silver composites with natural arabinogalactan polysaccharide as reducer and stabilizer is being developed at our laboratory. In the given work optical properties of the solutions during process of formation of silver nanoparticles have been studied. Nanosized mode of metals visually shows itself in absorption spectra as a plasmonic resonance. Thus, particle formation process can be spectrally controlled.


It has been established that optical properties of the particles strongly depend on the рН of medium. In electronic spectra of the solutions wide asymmetric bands of low intensity (l 420-470 nm) typical for initial metal silver clasters are observed starting from рН=5. At рН=9 the bands are transformed to characteristic plasmonic absorption (lmax 420 nm) conditioned by collective excitation of nanosized silver electrons supporting conductivity. Spectrum dynamics at рН>10 points to a gradual change of nanosized silver state parameters in the course of reaction. Observations upon solutions with various silver-arabinogalactan ratios have proved that it is possible to control the position of plasmonic absorption maximum. The shifts controlled in plasmonic absorption spectrum of nanoparticles demonstrate the interrelationship with size parameters. The results were obtained for solid samples of the composites by X-ray diffraction analysis data.


The determined principles of the process for nanosized silver formation are perspective for direct regulation of its optical properties which can be applied in development of new materials with controlled non-linear optical characteristics and optical markers in biology and medicine.

 

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Presentation: Oral at E-MRS Fall Meeting 2008, Symposium E, by Galina P. Aleksandrova
See On-line Journal of E-MRS Fall Meeting 2008

Submitted: 2008-05-16 12:44
Revised:   2009-06-07 00:48