Optical Properties of Shaped Silver Nanoparticles

2008 ◽  
Vol 8 (7) ◽  
pp. 3511-3515 ◽  
Author(s):  
Vesna V. Vodnik ◽  
Dušan K. Božanić ◽  
Nataša Bibić ◽  
Zoran V. Šaponjić ◽  
Jovan M. Nedeljković
Keyword(s):  
Silver Nanoparticles ◽  
Optical Properties ◽  
Absorption Spectrum ◽  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Nanocomposite Film ◽  
Reducing Agent ◽  
Plasmon Resonance Band ◽  
Resonance Band

The influence of shape and dielectric property of surrounding media on surface plasmon absorption band of silver nanoparticles was studied. Spherical silver nanoparticles (d = 5.6 nm) synthesized in water using NaBH4 as a reducing agent are transferred in non-polar solvent (chloroform) with phase-transfer reagent oleylamine. The absorption spectrum of oleylamine-capped silver nanoparticles dispersed in chloroform shows a strong surface plasmon resonance band that is 19 nm red-shifted compared to unmodified particles in water. The values for peak position and corresponding half widths are compared with theoretical calculations based on Mie theory. Prismatic and plate-like silver nanoparticles were synthesized in water using trisodium citrate as a reducing agent and cetyltrimethylammonium bromide as stabilizer. Due to structural anisotropy of prismatic and plate-like silver nanoparticles three surface plasmon resonance bands were observed in absorption spectrum. Nanocomposites consisting of non-spherical silver nanoparticles and polyvinyl alcohol exhibit different optical properties compared to water colloid. Instead of three surface plasmon bands, nanocomposite film has only one peak at 460 nm. Reason for appearance of single surface plasmon resonance band in nanocomposite film was discussed according to Maxwell-Garnet theory.

scholarly journals Investigation of the Influence of the Molecular Weight of Polyethyleneglycols on the Optical Properties and Dispersed Characteristics of Sols of Au Nanoparticles used in Medicine

2021 ◽  
pp. 268-280
Author(s):  
Abdul-Fattah Visirkhazhievich Ibragimov ◽  
Iman Ibragimovna Magomadova ◽  
Maryana Vyacheslavovna Teberdieva ◽  
Seda Alievna Ferzauli ◽  
Tamila Muslimovna Dolaeva ◽  
...  
Keyword(s):  
Optical Properties ◽  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Optical Density ◽  
Plasmon Resonance ◽  
Hydrodynamic Radius ◽  
Au Nanoparticles ◽  
Plasmon Resonance Band ◽  
Resonance Band ◽  
Peg 8000

In this work, the synthesis of Au nanoparticles stabilized with polyethyleneglycols with different molecular weights from 200 to 8000 Da was carried out. The synthesis was carried out by the method of chemical reduction in an aqueous medium using sodium citrate as a reducing agent. The dependence of the optical properties on the concentration and molar mass of polyethyleneglycol was studied in the obtained samples of Au nanoparticles. The absorption spectra were recorded using an SF-56 optical spectrometer. The studies were carried out in the visible range of the spectrum from 400 to 800 nm. It was found that the type of spectrum, the position of the surface plasmon resonance band and the optical density of the samples of Au nanoparticles stabilized with PEG-8000 with a concentration of 10 and 20% did not undergo significant changes during storage, which characterizes the high aggregate stability of these sols. The dispersed characteristics of these samples of sols of Au nanoparticles were also studied. The studies were carried out using photon-correlation spectroscopy by the method of dynamic light scattering. It is established that an increase in the concentration of the stabilizer leads to an increase in the average hydrodynamic radius of the particles. This fact is associated with an increase in the thickness of the stabilizer layer and with the "stitching" of the polymer layer of Au nanoparticles with the formation of aggregates. Thus, the best result was found in PEG-8000 samples with concentrations of 10 and 20%, since the type of spectrum, the position of the surface plasmon resonance band and the optical density did not undergo significant changes. Based on the data obtained, it can be concluded that the best stabilizer for Au nanoparticles obtained by the citrate method is PEG-8000 with a concentration of at least 10 %. It is important to note that with an increase in the concentration of the stabilizer, the average hydrodynamic radius of the particles increases. This fact is associated with an increase in the thickness of the stabilizer layer and with the "stitching" of Au nanoparticles.

Multiwavelength excitation of photosensitizers interacting with gold nanoparticles and its impact on optical properties of their hybrid mixtures

2015 ◽  
Vol 17 (41) ◽  
pp. 27366-27372 ◽  
Author(s):  
Michał Kotkowiak ◽  
Alina Dudkowiak
Keyword(s):  
Gold Nanoparticles ◽  
Optical Properties ◽  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Surface Plasmon Resonance Band ◽  
Plasmon Resonance Band ◽  
Resonance Band ◽  
Hybrid Mixtures

Different behavior of the mixtures on excitation with the wavelengths from the Soret and Q bands of the dyes and with those corresponding to the surface plasmon resonance band of gold nanoparticles, was analyzed.

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