Optical Properties and Detection Sensitivity of Noble Metal Nanoparticles

2018 ◽  
Vol 10 (3) ◽  
pp. 346-350
Author(s):  
Hongyan Zhao ◽  
Xin Liu ◽  
Shoubao Zhang ◽  
Xiaoli Liu ◽  
Rende Ma ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Silver Nanoparticles ◽  
Refractive Index ◽  
Extinction Spectrum ◽  
Spectral Characteristics ◽  
Resonance Wavelength ◽  
Detection Sensitivity ◽  
Noble Metal Nanoparticles ◽  
Localized Surface Plasmon ◽  
Refractive Indices

By using the finite difference time domain method, the localized surface plasmon extinction spectrum of different sizes of spherical gold and silver nanoparticles were simulated and analyzed in external environments with various refractive indices. It was observed that the changes in the position of the resonance wavelength were linearly proportional to the external refractive index, while the sensitivity increased with nanoparticle size. The sensitivity of the spherical silver nanoparticles with a radius of 40 nm reached 122 nm/RIU. For the silver and gold nanoparticles of the same size, the sensitivity of the silver nanoparticles was greater than that of the gold nanoparticles. In the experiment, the spectral characteristics of the silver nanoparticles with different sizes under various external refractive indices were measured. The experimental results were consistent with the simulation results. The resonance wavelength and the concentration of the solution showed a good linear relationship. By using the sensitive properties of the nanoparticles such as external refractive index, the amount of sucrose in the solution can be measured.

scholarly journals Optical Nonlinear Refractive Index of Laser-Ablated Gold Nanoparticles Graphene Oxide Composite

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Amir Reza Sadrolhosseini ◽  
A. S. M. Noor ◽  
Nastaran Faraji ◽  
Alireza Kharazmi ◽  
Mohd. Adzir Mahdi
Keyword(s):  
Particle Size ◽  
Gold Nanoparticles ◽  
Refractive Index ◽  
Graphene Oxide ◽  
Gold Nanoparticle ◽  
Spherical Shape ◽  
Refractive Indices ◽  
Hydroxyl Groups ◽  
Uv Visible ◽  
Laser Ablation Technique

Gold nanoparticles were prepared in graphene oxide using laser ablation technique. The ablation times were varied from 10 to 40 minutes, and the particle size was decreased from 16.55 nm to 5.18 nm in spherical shape. The nanoparticles were capped with carboxyl and the hydroxyl groups were obtained from Fourier transform infrared spectroscopy. Furthermore, the UV-visible peak shifted with decreasing of nanoparticles size, appearing from 528 nm to 510 nm. The Z-scan technique was used to measure the nonlinear refractive indices of graphene oxide with different concentrations and a gold nanoparticle graphene oxide nanocomposite. Consequently, the optical nonlinear refractive indices of graphene oxide and gold nanoparticle graphene oxide nanocomposite were shifted from1.63×10-9 cm2/W to4.1×10-9 cm2/W and from1.85×10-9 cm2/W to5.8×10-9 cm2/W, respectively.

scholarly journals Light harvesting enhancement using metal nanoparticles

2021 ◽  
Vol 2 (5 (110)) ◽  
Author(s):  
Mohammad Tariq Yaseen
Keyword(s):  
Silver Nanoparticles ◽  
Optical Properties ◽  
Metal Nanoparticles ◽  
Light Harvesting ◽  
Field Enhancement ◽  
Optical Response ◽  
Resonance Wavelength ◽  
Optical Field ◽  
Localized Surface Plasmon ◽  
Gold And Silver Nanoparticles

Metal nanoparticles are very important for their optical properties when they interact with light. Metal nanoparticles have the ability to confine the collective oscillation of electrons, which is called localized surface plasmon resonance (LSPR). In this work, silver nanoparticles have been proposed to enhance light harvesting, which could be useful for different applications. Metal nanoparticles such as gold and silver nanoparticles have the ability to concentrate field in a very small space. In this study, gold and silver nanoparticles optical response was investigated using frequency domain simulation. The resonance wavelength of gold and silver nanoparticles was about 550 nm and 400 nm, respectively. Silver nanoparticles showed better LSPR performance than gold nanoparticles. Therefore, silver nanoparticles were chosen for optical field enhancement. Here silver nanoparticles were placed on a silicon substrate for optical field enhancement. To study the effect of size on the optical response of silver nanoparticles, the optical properties of this structure with different silver nanoparticles diameter values were investigated. Silver nanoparticles with 40 nm diameters showed a better optical response. To study the effect of the distance between silver nanoparticles on the optical response, different gap values were put between silver nanoparticles. The gap value of 4 nm showed a better optical response. The obtained results showed that the localized field is strongly dependent on the metal type, size, and space between nanoparticles. In addition, the optical field concentration can be controlled by tuning the size and space between silver nanoparticles. This will support localized field enhancement. The enhanced localized field will increase the field absorption near the surface, which can be beneficial for energy harvesting applications such as solar cells and detectors

scholarly journals LSPR Biosensing Approach for the Detection of Microtubule Nucleation

Sensors ◽  
2019 ◽  
Vol 19 (6) ◽  
pp. 1436 ◽  
Author(s):  
Keisuke Hasegawa ◽  
Otabek Nazarov ◽  
Evan Porter
Keyword(s):  
Gold Nanoparticles ◽  
Refractive Index ◽  
Theoretical Model ◽  
Density Measurement ◽  
Localized Surface Plasmon ◽  
Proof Of Concept ◽  
Microtubule Nucleation ◽  
Cellular Processes ◽  
Microtubule Formation ◽  
Local Refractive Index

Microtubules are dynamic protein filaments that are involved in a number of cellular processes. Here, we report the development of a novel localized surface plasmon resonance (LSPR) biosensing approach for investigating one aspect of microtubule dynamics that is not well understood, namely, nucleation. Using a modified Mie theory with radially variable refractive index, we construct a theoretical model to describe the optical response of gold nanoparticles when microtubules form around them. The model predicts that the extinction maximum wavelength is sensitive to a change in the local refractive index induced by microtubule nucleation within a few tens of nanometers from the nanoparticle surface, but insensitive to a change in the refractive index outside this region caused by microtubule elongation. As a proof of concept to demonstrate that LSPR can be used for detecting microtubule nucleation experimentally, we induce spontaneous microtubule formation around gold nanoparticles by immobilizing tubulin subunits on the nanoparticles. We find that, consistent with the theoretical model, there is a redshift in the extinction maximum wavelength upon the formation of short microtubules around the nanoparticles, but no significant change in maximum wavelength when the microtubules are elongated. We also perform kinetic experiments and demonstrate that the maximum wavelength is sensitive to the microtubule nuclei assembly even when microtubules are too small to be detected from an optical density measurement.

Silver Nanocolloid: Synthesis, Optical and Thermo-Optical Properties

2013 ◽  
Vol 829 ◽  
pp. 670-674 ◽  
Author(s):  
Sakineh Hashemizadeh ◽  
Majid Rashidi Huyeh
Keyword(s):  
Silver Nanoparticles ◽  
Optical Properties ◽  
Extinction Spectrum ◽  
Noble Metal Nanoparticles ◽  
Shape Effect ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Different Temperatures ◽  
Two Peaks ◽  
Silver Nanocolloid

Linked to Surface Plasmon Resonance (SPR) phenomena, optical and thermo-optical properties of metal-dielectric nanocomposite materials including noble metal nanoparticles dispersed in a dielectric host medium are worthily interested. Indeed these materials have been proposed for many applications such as photonics devices, bio sensors and even photo-thermal therapy. Colloidal silver nanoparticles were synthesized by reduction of silver nitrate using of ascorbic acid and citrate as stabilizer agent in a 30°C water bath. The transmission electron microscopy (TEM) micrograph image shows formation of spheroidal silver nanoparticles with an average of large and small diameters about 43 and 34 nm respectively. Extinction spectrum, measured using UV-Vis spectroscopy, represented two peaks located around 420 and 620 nm of wavelength. These peaks are attributed to SPR phenomena and confirm spheroidal and spherical silver nanoparticle formation in solution. Thermo-optical properties of synthesized silver nanocolloids are then evaluated by measuring of extinction spectrum at different temperatures. Results showed an enhancement in thermo-optical properties of silver nanocolloids around the SPR wavelengths. Theoretical analysis, done using Mie and Mie-Gans theories, showed that the different peaks observed in extinction spectrum are related directly to shape effect.

Experimental Study of Enhancement and Quenching of Plasmon-Controlled Fluorescence Using Quantum Dot–Plasmonic Nanoparticle Mixtures in Aqueous Medium

2012 ◽  
Author(s):  
Nola Palombo ◽  
Timothy Walsh ◽  
Jungchul Lee ◽  
Keunhan Park
Keyword(s):  
Gold Nanoparticles ◽  
Silver Nanoparticles ◽  
Quantum Dot ◽  
Near Field ◽  
Emission Spectra ◽  
Emission Wavelength ◽  
Localized Surface Plasmon ◽  
Excitation Wavelength ◽  
Distilled Water ◽  
Plasmonic Nanoparticle

This article reports the enhancement and quenching of quantum dot (QD) emission for different concentrations of plasmonic nanoparticles (PNPs) by utilizing the Brownian motion-induced dynamic near-field interactions in aqueous solution. We measured the fluorescence spectrum of two types of QD-PNP mixtures. The first mixture was QDs (525 nm for emission wavelength) and gold nanoparticles dispersed in distilled water, where the emission wavelength of the QDs matches the localized surface plasmon (LSP) excitation wavelength of the gold nanoparticles. The second mixture was QDs (655 nm for emission wavelength) and silver nanoparticles dispersed in distilled water, where LSPs excited at the wavelength of 392 nm affect the excitation of the QDs. For both experiments, the QD emission spectra were monitored while changing the concentration of the PNPs from 108 to 1011 /mL for a fixed concentration of QDs at 1 × 1013 /mL. For low PNP concentrations, the QD emission was enhanced for 30 nm gold nanoparticles and 80 nm silver nanoparticles; however, for high PNP concentrations, the QD emission was always quenched. This research reveals the dependence of the QD fluorescence on the concentration of PNPs. The obtained results will be beneficial in further understanding plasmonic interactions between QDs and nanoparticles and the manipulation of QD emission, switching from enhancement to quenching or vice versa, with the alteration of nanoparticle concentration.

scholarly journals Technical note: optical extinction coefficient of polydisperse spherical gold nanoparticles in water

2017 ◽  
Vol 12 (4) ◽  
Author(s):  
Jia Cherng Chong ◽  
Lee Siew Ling ◽  
Noriah Bidin
Keyword(s):  
Gold Nanoparticles ◽  
Extinction Coefficient ◽  
Spectral Characteristics ◽  
Particle Diameter ◽  
Resonance Wavelength ◽  
Dipole Approximation ◽  
Technical Note ◽  
Particle Sizes ◽  
Optical Extinction ◽  
Plasmon Resonance Peak

The extinction coefficients of polydispersed gold nanoparticles up to σ = 360 nm were computed via exact solution of Mie theory. A narrow extinction peak around 520 nm occurs for mean particle sizes <d> within dipole approximation limit. Spectral characteristics for extinction coefficient computed based on increasing mean particle sizes, degree of polydispersity, composition ratio of bimodal size distributions and changes in dispersant temperature are compared. As mean particle sizes increases, the plasmon resonance peak red-shifts and broadens skewing towards infrared. Increasing polydispersity on mean particle diameter beyond dipole approximation limit decreases peak extinction coefficient values. Increasing temperature from ambient to boiling changes the peak extinction coefficient intensity value by an order of 10^-13 while resonance wavelength remains unchanged.

scholarly journals Shape Effect on the Refractive Index Sensitivity at Localized Surface Plasmon Resonance Inflection Points of Single Gold Nanocubes with Vertices

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Hui Bin Jeon ◽  
Philippe Vuka Tsalu ◽  
Ji Won Ha
Keyword(s):  
Gold Nanoparticles ◽  
Refractive Index ◽  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Localized Surface Plasmon Resonance ◽  
Localized Surface Plasmon ◽  
Shape Effect ◽  
Frequency Shifts ◽  
Inflection Points

Abstract Plasmonic gold nanoparticles with sharp tips and vertices, such as gold bipyramids (AuBPs) and gold nanocubes (AuNCs), have been widely used for high-sensitivity localized surface plasmon resonance (LSPR) sensing. However, conventional LSPR sensors based on frequency shifts have a major disadvantage: the asymmetry and broadening of LSPR peaks because of instrumental, environmental, and chemical noises that limit the precise determination of shift positions. Herein, we demonstrated an alternative method to improve the efficiency of the sensors by focusing on homogeneous LSPR scattering inflection points (IFs) of single gold nanoparticles with a single resonant mode. In addition, we investigated the effect of the shape and vertices of AuNCs on the refractive index (RI) sensitivity of homogeneous LSPR IFs by comparing with gold nanospheres (AuNSs) of similar size. The results show that for both AuNCs and AuNSs, tracking homogeneous LSPR IFs allows for higher RI sensitivity than tracking the frequency shifts of the LSPR peaks. Furthermore, single AuNCs with vertices exhibited higher RI sensitivity than single AuNSs of similar size in the homogeneous LSPR IFs. Therefore, we provided a deeper insight into the RI sensitivity of homogeneous LSPR IFs of AuNCs with vertices for their use in LSPR-based biosensors.

Sign in / Sign up

Export Citation Format

Share Document