Tuning the photoluminescence and ultrasensitive trace detection properties of few-layer MoS2 by decoration with gold nanoparticles

RSC Advances ◽  
2015 ◽  
Vol 5 (31) ◽  
pp. 24188-24193 ◽  
Author(s):  
Shib Shankar Singha ◽  
Dipanjan Nandi ◽  
Achintya Singha
Keyword(s):  
Gold Nanoparticles ◽  
Optical Properties ◽  
Molecular Detection ◽  
Au Nanoparticle ◽  
Trace Detection ◽  
Detection Capabilities

Tuning the optical properties and ultrasensitive molecular detection capabilities of Au nanoparticle-decorated MoS2.

scholarly journals The effect of gold nanoparticles on WO3 thin film

2018 ◽  
Vol 16 (36) ◽  
pp. 11-28
Author(s):  
Isam M. Ibrahim
Keyword(s):  
Thin Film ◽  
Gold Nanoparticles ◽  
Optical Properties ◽  
Substrate Temperature ◽  
Annealing Temperature ◽  
Energy Gap ◽  
Spray Pyrolysis Technique ◽  
Oxide Thin Film ◽  
Au Nanoparticle ◽  
Chemical Spray Pyrolysis

Chemical spray pyrolysis technique was used at substrate temperature 250 ˚C with annealing temperature at 400 ˚C (for 1hour) to deposition tungsten oxide thin film with different doping concentration of Au nanoparticle (0, 10, 20, 30 and 40)% wt. on glass substrate with thickness about 100 nm. The structural, optical properties were investigated. The X-ray diffraction shows that the films at substrate temperature (250 ˚C) was amorphous while at annealing temperature have a polycrystalline structure with the preferred orientation of (200), all the samples have a hexagonal structure for WO3 and Au gold nanoparticles have a cubic structure. Atomic force microscopy (AFM) was used to characterize the morphology of the films. The optical properties of the films were studied using UV-Vis spectrophotometer within the wavelength in the range (300-1100) nm. The optical energy gap of the films was (2.80) eV for WO3 and it decreased at annealing temperature (400 ˚C) equal to (2.65) eV. And finally the optical constants such as refractive index, real and imaginary dielectrics, absorption coefficient, absorption, transmission, and extinction coefficient were investigated.

An Effort to Making a Colorimitric Nano-Biosensor for Vibrio cholera Detection

2020 ◽  
Vol 16 (5) ◽  
pp. 793-804
Author(s):  
Naimeh Mahheidari ◽  
Jamal Rashidiani ◽  
Hamid Kooshki ◽  
Khadijeh Eskandari
Keyword(s):  
Gold Nanoparticles ◽  
Colorimetric Assay ◽  
Au Nanoparticle ◽  
Bacteria Detection ◽  
Great Promise ◽  
Bacterial Cells ◽  
Vibrio Cholera ◽  
Minimum Concentration ◽  
Vis Spectroscopy ◽  
Fast Procedure

Background: Today, nanoparticles hold great promise in biomedical researches and applications including bacteria detection. The rapid and sensitive outcomes of bacteria detection strategies using nanoparticle conjugates become determinative, especially in bacterial outbreaks. In the current research, we focused on detecting V. cholera bacteria and its toxin using a thiocyanate/Au nanoparticle. Thiocyanate adsorbed strongly on the surface of gold nanoparticles and changed the surface by enhancing surface plasmon resonance of gold nanoparticles. Objective: This method is tried to introduce a simple and fast procedure to assay vibrio cholera. So, it is observed by the naked eyes as well. Methods: We used two antibodies (Ab) for V. cholera detection: a) a primary antibody conjugated to magnetic nanoparticles (MNPs) for trapping V. cholera bacterial cells, and b) a secondary Abconjugated thiocyanate-GNPs as a colorimetric detector. Then, an immuno-magnetic separation system connected to a colorimetric assay was designed based on the GNPs. The results were measured by ultraviolet-visible (UV-Vis) spectroscopy. Results: The results showed that gold nanoparticles are an appropriate optical assay for detecting biological samples in a minimum concentration and also it can be easily seen by the naked eyes. The linear range of this biosensor is 3.2×104 to 28×104 cells per ml. Conclusion: In this research, a colorimetric immune assay based on gold nanoparticles was designed to improve the sensitivity of V. cholera detection. Also, this method can be used for the detection of other biological agents.

scholarly journals Molecular detection using aptamer-modified gold nanoparticles with an immobilized DNA brush for the prevention of non-specific aggregation

RSC Advances ◽  
2021 ◽  
Vol 11 (20) ◽  
pp. 11984-11991
Author(s):  
Yuki Yano-Ozawa ◽  
Nadine Lobsiger ◽  
Yu Muto ◽  
Takahiro Mori ◽  
Ken Yoshimura ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Molecular Detection ◽  
Darkfield Microscopy

We demonstrated molecular detection using aptamer-modified gold nanoparticles with DNA-brush for the prevention of non-specific aggregation and smartphone darkfield microscopy.

High Density Gold Nanoparticles Within Three-Dimensionally Mesoporous SBA-15: Adsorption Behavior and Optical Properties

2015 ◽  
Vol 15 (9) ◽  
pp. 7060-7067 ◽  
Author(s):  
Xiaojuan Wang ◽  
Xiaoqing Yan ◽  
Renhong Li ◽  
Liping Xiao ◽  
Guicen Ma ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Optical Properties ◽  
High Density ◽  
Adsorption Behavior

THEORETICAL MODEL FOR THE CALCULATION OF OPTICAL PROPERTIES OF GOLD NANOPARTICLES

2010 ◽  
Vol 19 (03) ◽  
pp. 427-436
Author(s):  
A. MENDOZA-GARCÍA ◽  
A. ROMERO-DEPABLOS ◽  
M. A. ORTEGA ◽  
J. L. PAZ ◽  
L. ECHEVARRÍA
Keyword(s):  
Gold Nanoparticles ◽  
Refractive Index ◽  
Optical Properties ◽  
Theoretical Model ◽  
Absorption Coefficient ◽  
Molecular System ◽  
Two Dimensional ◽  
Box Models ◽  
Solvent Environment ◽  
Absorption And Dispersion

We have developed an analytical method to describe the optical properties of nanoparticles, whose results are in agreement with the observed experimental behavior according to the size of the nanoparticle under analysis. Our considerations to describe plasmonic absorption and dispersion are based on the combination of the two-level molecular system and the two-dimensional quantum box models. Employing the optical stochastic Bloch equations, we have determined the system's coherence, from which we have calculated expressions for the absorption coefficient and refractive index. The innovation of this methodology is that it allows us to take into account the solvent environment, which induce quantum effects not considered by classical treatments.

Optical properties of nanostructured carbon and gold nanoparticle hybrids

2014 ◽  
Vol 1700 ◽  
pp. 79-82 ◽  
Author(s):  
Yuan Li ◽  
Nitin Chopra
Keyword(s):  
Gold Nanoparticles ◽  
Optical Properties ◽  
Hot Spots ◽  
Simulation Method ◽  
Dipole Approximation ◽  
Multilayer Graphene ◽  
Nanostructured Carbon ◽  
Near Surface ◽  
Scattering Effects ◽  
Dda Method

ABSTRACTWe report simulation of optical properties of hybrid geometry comprised of multilayer graphene shell encapsulated gold nanoparticles loaded with carbon nanotubes. The discrete dipole approximation (DDA) method was employed. The results indicated that the optical properties of encapsulated gold nanoparticles were not suppressed by the carbon material coating. Furthermore, low scattering effects were also observed. The simulation method helped visualize the near-surface normalized electric field, which is directly related to the intensity of hot spots on the surface of these hybrid nanoarchitectures.

scholarly journals Optical Properties of Star-Shaped Gold Nanoparticles

Nano Letters ◽  
2006 ◽  
Vol 6 (4) ◽  
pp. 683-688 ◽  
Author(s):  
Colleen L. Nehl ◽  
Hongwei Liao ◽  
Jason H. Hafner
Keyword(s):  
Gold Nanoparticles ◽  
Optical Properties
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