Influence of Oxygen on the Optical Properties of Silver Nanoparticles

2008 ◽  
Vol 8 (12) ◽  
pp. 6545-6550 ◽  
Author(s):  
V. M. Rentería-Tapia ◽  
J. García-Macedo
Keyword(s):  
Silver Nanoparticles ◽  
Optical Properties ◽  
Metallic Nanoparticles ◽  
Silver Oxide ◽  
Sol Gel ◽  
Oxygen Atmosphere ◽  
Oxide Shell ◽  
Metallic Surface ◽  
Oxidizing Atmosphere ◽  
Vis Spectroscopy

Silver nanoparticles in sol–gel silica films were obtained by annealing in hydrogen atmosphere and subsequently in oxygen atmosphere. Their properties were measured by UV-vis spectroscopy, transmission electron microscopy (TEM), high-resolution transmission electronic microscopy (HRTEM) and X-ray diffraction analysis. Samples prepared in a reducing atmosphere exhibited a surface plasmon resonance (SPR) located at 399 nm. Silver nanoparticles in an oxidizing atmosphere exhibited a red shift and damping of the SPR. These optical properties were explained due to the oxidation on the surface of silver nanoparticles to silver oxide yield in an oxygen atmosphere. Silver core–silver oxide shell nanostructures were observed by HRTEM. The average size of the metallic nanoparticles obtained by TEM was used for modeling the UV-vis spectra by using the Gans theory. Good fits to the spectra under an oxidizing atmosphere were obtained considering variable refractive indexes coming from the silver oxide shells surrounding to the nanoparticles. Therefore, the interaction between oxygen and the metallic surface of the nanoparticles, sensitively alters their optical properties.

Silver Core - Silver Oxide Shell Nanoparticles Embedded on Mesostructured Silica Films

2008 ◽  
Vol 3 ◽  
pp. 103-114 ◽  
Author(s):  
Guadalupe Valverde-Aguilar ◽  
Jorge A. García-Macedo ◽  
Víctor Rentería-Tapia
Keyword(s):  
Silver Nanoparticles ◽  
Refractive Index ◽  
Optical Properties ◽  
Absorption Spectrum ◽  
Silver Oxide ◽  
High Refractive Index ◽  
Oxide Shell ◽  
Metallic Silver ◽  
Type I ◽  
Silver Core

Metallic silver particles in the nanometer size range were obtained in SiO2 matrix by the reduction of AgNO3 with the non-ionic diblock copolymer (Brij 58). Hexagonal mesostructured sol-gel films were synthesized by dip-coating method using the surfactant Brij58 to produce channels into the film, which house the silver nanoparticles. Optical properties of the metallic nanoparticles were studied by UV-Vis spectroscopy, TEM and HRTEM images. The experimental absorption spectrum of the metallic silver nanoparticles exhibits an absorption band located at 438 nm and a shoulder at longer wavelength. The TEM images show randomly distributed silver nanoparticles (Type I) along with some oriented as long line (Type II). Both distributions exhibit a silver oxide shell around of them. The second shell covering the silver core - silver oxide shell system is related to the surfactant. The optical absorption spectrum was modelled using the Gans theory. The fit shows two main contributions related to metallic silver nanoparticles with different axial ratios, and surrounding of a dielectric medium with high refractive index. Presence of the high refractive index silver oxide shell was confirmed by X-ray diffraction technique. The contributions of silver core and silver oxide shell play important roles in the optical properties of the films.

The Structural, Magnetic and Optical Properties of Ni-Mg-Zn Ferrite Prepared With Different Complexing Agents via Sol-Gel Method

2021 ◽  
Author(s):  
Yanchun Zhang ◽  
Aimin Sun ◽  
Zhaxi Suonan
Keyword(s):  
Optical Properties ◽  
Electron Microscope ◽  
Sol Gel ◽  
Complexing Agents ◽  
Complexing Agent ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Zn Ferrite ◽  
Vis Spectroscopy

Abstract Different complexing agents were used to prepare Ni-Mg-Zn ferrite with the composition formula Ni0.2Mg0.2Zn0.6Fe2O4 via sol-gel method, which included citric acid, oxalic acid, egg white and EDTA. The Ni0.2Mg0.2Zn0.6Fe2O4 ferrite with no complexing agent was also prepared as a comparison. The chemical phases of samples were analyzed by the X-ray diffraction (XRD), which indicated that samples had spinel phase structure. The lattice constants of samples are in the range of 8.3980 ~ 8.4089 Å. The composition and structure were further studied by fourier transform infrared spectroscopy (FTIR). There were two typical characteristic bands related to the stretching vibrations of spinel ferrite in FTIR spectra. Scanning electron microscope (SEM) micrographs and transmission electron microscope (TEM) images showed that the particles have the shape of spherical cube. Energy dispersive spectrometer (EDS) analyzed the elements and ingredients of samples, which included Ni, Mg, Zn, Fe and O. X-ray photoelectron spectroscopy (XPS) is used to examine further the elemental composition and chemical state of sample prepared with EDTA as complexing agent. The optical properties of samples were investigated by photoluminescence spectra and UV-Vis spectroscopy. Vibrating sample magnetometer (VSM) was used to characterize magnetic properties, hysteresis loops revealed the ferrimagnetism behavior of prepared samples.

scholarly journals Fabrication of Ag-modified hollow titania spheres via controlled silver diffusion in Ag–TiO2 core–shell nanostructures

2020 ◽  
Vol 11 ◽  
pp. 141-146 ◽  
Author(s):  
Bartosz Bartosewicz ◽  
Malwina Liszewska ◽  
Bogusław Budner ◽  
Marta Michalska-Domańska ◽  
Krzysztof Kopczyński ◽  
...  
Keyword(s):  
Optical Properties ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Hollow Spheres ◽  
Good Control ◽  
Structural Features ◽  
Noble Metal Nanoparticles ◽  
Simple Method ◽  
Vis Spectroscopy ◽  
Silver Diffusion

Inorganic hollow spheres find a growing number of applications in many fields, including catalysis and solar cells. Hence, a simple fabrication method with a low number of simple steps is desired, which would allow for good control over the structural features and physicochemical properties of titania hollow spheres modified with noble metal nanoparticles. A simple method employing sol–gel coating of nanoparticles with titania followed by controlled silver diffusion was developed and applied for the synthesis of Ag-modified hollow TiO2 spheres. The morphology of the synthesized structures and their chemical composition was investigated using SEM and X-ray photoelectron spectroscopy, respectively. The optical properties of the synthesized structures were characterized using UV–vis spectroscopy. Ag–TiO2 hollow nanostructures with different optical properties were prepared simply by a change of the annealing time in the last fabrication step. The synthesized nanostructures exhibit a broadband optical absorption in the UV–vis range.

Enhanced Electrical Properties of AZO/IZO Multilayered Thin Film with Post Laser Annealing Process

2021 ◽  
Vol 21 (3) ◽  
pp. 1971-1977
Author(s):  
Jihye Kang ◽  
Dongsu Park ◽  
Donghun Lee ◽  
Masao Kamiko ◽  
Sung-Jin Kim ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Optical Properties ◽  
Multilayer Structure ◽  
Laser Annealing ◽  
Transparent Conducting Oxide ◽  
Sol Gel ◽  
Electrical And Optical Properties ◽  
Vis Spectroscopy ◽  
Doped Zno

In this research, alternative deposition process of ZnO-based thin films have been studied for transparent conducting oxide (TCO) application. To improve the electrical and optical properties of transparent oxide thin films, alternatively stacked Al-doped ZnO and In-doped ZnO thin films were investigated. Multilayer structure of alternative 6 layers of thin films were prepared in this research. Especially, Aluminum and Indium were chosen as dopant materials. Thin films of Al-doped ZnO (AZO) and In-doped ZnO (IZO) were alternatively deposited by spin coating with sol-gel method. After deposition of multilayered thin films, multi steps of furnace (F), rapid thermal annealing (R) and CO2 laser annealing (L) processes were carried out and investigated thin film properties by dependence of post-annealing sequence and thin film structures. The electrical and optical properties of thin films were investigated by 4-point probe and UV-vis spectroscopy and its shows the greatest sheet resistance value of 0.59 kΩ/sq. from AZO/IZO multilayered structure and upper 85% of transmittance. The structural property and surface morphology were measured by X-Ray Diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The Al- and In-doped ZnO thin film shows the highest intensity value at (002) peak of AZO/IZO multilayer structure which was performed FRL process.

scholarly journals Influence of Preparation Method on the Structural, Linear and Nonlinear Optical Properties of TiN Nanoparticles

2021 ◽  
Author(s):  
Mahdi Safa ◽  
Yasser Rajabi ◽  
Mahdi Ardyanian
Keyword(s):  
Optical Properties ◽  
Titanium Nitride ◽  
Nonlinear Optical ◽  
Sol Gel ◽  
Tin Nanoparticles ◽  
Vis Spectroscopy ◽  
Optical Applications ◽  
Co Precipitation ◽  
Optical Behavior ◽  
Saturation Absorption

Abstract In this paper, titanium nitride nanoparticles were prepared in three methods, In the first method, titanium nitride nanoparticles were prepared by the Ball-mill method; in the second and third methods, the nanoparticles were synthesized by the sol-gel, and the co-precipitation methods. The samples were characterized by X-ray diffraction (XRD), UV-Vis spectroscopy, and scanning electron microscopy (SEM), for the study of structural, linear optical properties, and surface morphology study, respectively. The Z-scan technique was utilized to study the TiN nanoparticles nonlinearity. A change in nonlinear optical behavior with an increase in input pump power and concentration of the TiN nanoparticles was observed. Results showed that the TiN nanoparticles give new potentials in nonlinear optical applications. The nonlinear optical behavior of the TiN nanoparticles shifts from inverse saturation absorption to saturation absorption with increase of intensity.

scholarly journals Study of Antibacterial Properties of Ziziphus mauritiana based Green Synthesized Silver Nanoparticles against Various Bacterial Strains

2020 ◽  
Vol 12 (4) ◽  
pp. 1484 ◽  
Author(s):  
M. Asimuddin ◽  
Mohammed Rafi Shaik ◽  
Neeshat Fathima ◽  
M. Shaistha Afreen ◽  
Syed Farooq Adil ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Metallic Nanoparticles ◽  
Low Cost ◽  
Preliminary Investigation ◽  
Antibacterial Properties ◽  
Silver Ions ◽  
Ziziphus Mauritiana ◽  
Bacterial Strains ◽  
Vis Spectroscopy ◽  
Ft Ir

Due to their low cost and environmentally friendly nature, plant extracts based methods have gained significant popularity among researchers for the synthesis of metallic nanoparticles. Herein, green synthesis of silver nanoparticles was performed using the aqueous solution of Ziziphus mauritiana leaves extract (ZM-LE) as a bio-reducing agent. The as-obtained silver nanoparticles were characterized by using UV-Vis spectroscopy, XRD (X-ray diffraction), TEM (transmission electron microscopy), and FT-IR (Fourier-transform infrared spectroscopy). In addition, the effects of the concentrations of the leaves extract, silver nitrate, and the temperature on the preparation of nanoparticles were also investigated. In order to determine the nature of secondary metabolites present in leaves extract, a preliminary investigation of phytoconstituents was carried out using different methods including Folin-Ciocalteu and AlCl3 methods. The results have indicated the presence of a considerable amount of phenolic and flavonoid contents in the leaves extract, which are believed to be responsible for the reduction of silver ions and stabilization of resulting nanoparticles. Indeed, the FT-IR spectrum of silver nanoparticles also confirmed the presence of residual phytomolecules of leaves extract as stabilizing ligands on the surface of nanoparticles. The antibacterial properties of as-obtained silver nanoparticles were tested against various bacterial strains including Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus subtilis. The nanoparticles strongly inhibited the growth of S. aureus with a minimum inhibitory concentration (MIC) of 2.5 μg/ml and moderately inhibited the growth of E. coli with a MIC of 5 μg/ml.

scholarly journals Optical properties of sol-gel coatings containing silver nanoparticles

2020 ◽  
Vol 911 ◽  
pp. 012007
Author(s):  
S N Stepin ◽  
T A Xolmurodov ◽  
O O Mirzaev ◽  
V E Katnov
Keyword(s):  
Silver Nanoparticles ◽  
Optical Properties ◽  
Sol Gel

scholarly journals One pot synthesis of silver nanoparticles using a cyclodextrin containing polymer as reductant and stabilizer

2014 ◽  
Vol 5 ◽  
pp. 380-385 ◽  
Author(s):  
Arkadius Maciollek ◽  
Helmut Ritter
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silver Nanoparticles ◽  
Optical Properties ◽  
Silver Nitrate ◽  
Room Temperature ◽  
One Pot ◽  
One Pot Synthesis ◽  
Transmission Electron ◽  
Vis Spectroscopy

A facile and one pot synthesis of silver nanoparticles with narrow size distributions using silver nitrate and a copolymer 1 from N-isopropylacrylamide (NIPAM) and mono-(1H-triazolylmethyl)-2-methylacryl-β-cyclodextrin acting as reductant and stabilizer without using any additional reducing agent is reported. The reduction was carried out in aqueous solution under pH neutral conditions at room temperature. The results of dynamic light scattering analysis and transmission electron microscopy show adjustable particle sizes from 30–100 nm, due to variation of silver nitrate concentration, the polymeric reducing and stabilisation agent concentration or reaction time. The spherical structure of the silver nanoparticles has been confirmed by UV–vis spectroscopy and transmission electron microscopy. The optical properties of the nanoparticles have also been characterized by fluorescence spectroscopy. The formed spherical particles are stable in aqueous medium at room temperature over a period of several weeks. Furthermore the changes in the optical properties of the nanoparticles due to thermo induced volume phase transition behavior of the thermoresponsive cyclodextrin containing polymer 1 have been characterized by UV–vis spectroscopy.

scholarly journals Investigation of Nanoparticle Metallic Core Antibacterial Activity: Gold and Silver Nanoparticles against Escherichia coli and Staphylococcus aureus

2021 ◽  
Vol 22 (4) ◽  
pp. 1905
Author(s):  
Jimmy Gouyau ◽  
Raphaël E. Duval ◽  
Ariane Boudier ◽  
Emmanuel Lamouroux
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Metallic Nanoparticles ◽  
Catalytic Reduction ◽  
Gold And Silver Nanoparticles ◽  
High Antibacterial Activity ◽  
Vis Spectroscopy ◽  
Broth Microdilution Method

Multidrug-resistant (MDR) bacteria constitute a global health issue. Over the past ten years, interest in nanoparticles, particularly metallic ones, has grown as potential antibacterial candidates. However, as there is no consensus about the procedure to characterize the metallic nanoparticles (MNPs; i.e., metallic aggregates) and evaluate their antibacterial activity, it is impossible to conclude about their real effectiveness as a new antibacterial agent. To give part of the answer to this question, 12 nm gold and silver nanoparticles have been prepared by a chemical approach. After their characterization by transmission electronic microscopy (TEM), Dynamic Light Scattering (DLS), and UltraViolet-visible (UV-vis) spectroscopy, their surface accessibility was tested through the catalytic reduction of the 4-nitrophenol, and their stability in bacterial culture medium was studied. Finally, the antibacterial activities of 12 nm gold and silver nanoparticles facing Staphylococcus aureus and Escherichia coli have been evaluated using the broth microdilution method. The results show that gold nanoparticles have a weak antibacterial activity (i.e., slight inhibition of bacterial growth) against the two bacteria tested. In contrast, silver nanoparticles have no activity on S. aureus but demonstrate a high antibacterial activity against Escherichia coli, with a minimum inhibitory concentration of 128 µmol/L. This high antibacterial activity is also maintained against two MDR-E. coli strains.

Sign in / Sign up

Export Citation Format

Share Document