scholarly journals Simulation of the optical properties of gold nanoparticles on sodium alginate

2021 ◽  
Vol 255 ◽  
pp. 08002
Author(s):  
Caterina Summonte ◽  
Piera Maccagnani ◽  
Alberto Maurizi ◽  
Giulio Pizzochero ◽  
Gabriele Bolognini

In this contribution, we report on the simulation of optical reflectance and transmittance (R&T) taken on a set of gold nanoparticles thin film, deposited on sodium alginate by magnetron sputtering. The gold layer is very thin, so that the films are not continuous and the material is arranged in nanostructured layers. R&T spectra are simulated using the Generalized Transfer Matrix method applied to the film-on-substrate model. The gold NP films are simulated using the Drude-Lorentz model, by taking into account that the optical function of nanostructured gold exhibits increased collision frequency and reduced relaxation time. Moreover, the signal of localized surface plasmon, evident in the spectra, is simulated by introducing a dedicated modified Lorentz oscillator. The experimental results are well reproduced by the applied model. All trends (amplitude and energy position of the plasmon oscillator, film thickness, relaxation time) are correlated with the deposition parameters. The procedure represents a useful tool in the characterisation of such nanoparticles thin films.

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1490
Author(s):  
Enrico Gazzola ◽  
Michela Cittadini ◽  
Marco Angiola ◽  
Laura Brigo ◽  
Massimo Guglielmi ◽  
...  

Solution processed TiO2 anatase film was used as sensitive layer for H2 detection for two plasmonic sensor configurations: A grating-coupled surface plasmon resonance sensor and a localized surface plasmon resonance sensor with gold nanoparticles. The main purpose of this paper is to elucidate the different H2 response observed for the two types of sensors which can be explained considering the hydrogen dissociation taking place on TiO2 at high temperature and the photocatalytic activity of the gold nanoparticles.


2021 ◽  
Author(s):  
Weixue Yang ◽  
Fei Li ◽  
Huali Liu ◽  
Zhen Li ◽  
Jiaqi Zhao ◽  
...  

A photo-assisted Li−Oxygen (Li−O2) battery with Au/SnO2 (ASO) hybrid nanotubes as cathode and photocatalyst has been prepared. The localized surface plasmon resonance (LSPR) excitation of gold nanoparticles (Au NPs) can...


Author(s):  
Richard Darienzo ◽  
Olivia Chen ◽  
Maurinne Sullivan ◽  
Tatsiana Mironava ◽  
Rina Tannenbaum

<p>Quasi-fractal gold nanoparticles can be synthesized via a modified and temperature controlled procedure initially used for the synthesis of star-like gold nanoparticles. The surface features of nanoparticles leads to improved enhancement of Raman scattering intensity of analyte molecules due to the increased number of sharp surface features possessing numerous localized surface plasmon resonances (LSPR). The LSPR is affected by the size and shape of surface features as well as inter-nanoparticle interactions, as these affect the oscillation modes of electrons on the nanoparticle surfaces. The effect of the particle morphologies on the LSPR and further on the surface-enhancing capabilities of these nanoparticles is explored by comparing different nanoparticle morphologies and concentrations. We show that in a fixed nanoparticle concentration regime, Quasi-fractal gold nanoparticles provide the highest level of surface enhancement, whereas spherical nanoparticles provide the largest enhancement in a fixed gold concentration regime. The presence of highly branched features enables these nanoparticles to couple with a laser wavelength despite having no strong absorption band and hence no single surface plasmon resonance. This cumulative LSPR may allow these nanoparticle to be used in a variety of applications where laser wavelength flexibility is beneficial, such as in medical imaging applications where fluorescence at short laser wavelengths may be coupled with non-fluorescing long laser wavelengths for molecular sensing. </p>


2021 ◽  
Vol 891 ◽  
pp. 43-48
Author(s):  
Muhammad Tegar Pambudi ◽  
Suhandoko Dwi Isro ◽  
Priastuti Wulandari

Gold nanoparticles (AuNP) has been used in a wide range of applications especially in medicine and optoelectronic applications due to its localized surface plasmon resonance (LSPR) effect. LSPR observation of AuNP solution shows that the plasmonic peak in the absorbance spectra lies in the range of visible light around 520 nm with deep red-wine color. The optical characteristic is controlled by the size and shape of the nanoparticles including its surface functionalization. Our research is focused on the adsorption study of 3-mercaptopropionate (3-MP) on AuNP (AuMP) surface synthesized by ligand exchange method and also by direct reduction method. The characterizations are conducted by use of UV-vis and FTIR spectroscopies in order to investigate the effect of LSPR. The absorbance spectra show that both experimental methods of AuMP give a similar profile of red-shifted in the plasmonic peaks in comparison to that of citrate-capped AuNP as a reference from 519 nm to 520 nm. The ligand exchange method of AuMP synthesis results in an unstable colloidal solution after being stored for a week at room temperature while the reduction method results in a stable colloidal solution of AuMP even though it has been stored for 2 months. The FTIR spectra show the difference in vibrational peak intensities between the 3-MP on AuNP and the 3-MPA as reference. The peak of carboxylate (COO-) asymmetric stretching is shifted to low frequency from 1708 cm-1 to 1632 cm-1 indicate the effect of LSPR while the shift to high frequencies for some vibrational peak intensities relates to the strong effect of chemical coordination between gold and capping material. The simulation of the vibration energy by use of the Density Functional Theory (DFT) method shows a similar tendency to that of the peak intensities along the infrared spectrum from experimental results.


RSC Advances ◽  
2020 ◽  
Vol 10 (51) ◽  
pp. 30858-30869
Author(s):  
Phuong Que Tran Do ◽  
Vu Thi Huong ◽  
Nguyen Tran Truc Phuong ◽  
Thi-Hiep Nguyen ◽  
Hanh Kieu Thi Ta ◽  
...  

The development of improved methods for the synthesis of monodisperse gold nanoparticles (Au NPs) is of high priority because they can be used as substrates for surface-enhanced Raman scattering (SERS) applications relating to biological lipids.


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