State-of-art of silver and gold nanoparticles synthesis routes, characterization and applications: a review

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Faisal Ali ◽  
Muhammad Hamza ◽  
Munawar Iqbal ◽  
Beriham Basha ◽  
Norah Alwadai ◽  
...  
Keyword(s):  
Electron Microscope ◽  
X Rays ◽  
Ag Nps ◽  
Au Nps ◽  
Advantages And Disadvantages ◽  
Transmission Electron ◽  
Synthesis Properties ◽  
Synthesis Routes ◽  
Synthesis Approach ◽  
Comprehensive Study

Abstract To date, the noble metal-based nanoparticles have been used in every field of life. The Au and Ag nanoparticles (NPs) have been fabricated employing different techniques to tune the properties. In this study, the methodologies developed and adopted for the fabrication of Au and Ag have been discussed, which include physical, chemical and biological routes. The Au and Ag characteristics (morphology, size, shape) along with advantages and disadvantages are discussed. The Au and Ag NPs catalytic and biomedical applications are discussed. For the Ag and Au NPs characterization, SEM (scanning electron microscope), TEM (transmission electron microscope), FTIR (Fourier transform infra-red spectroscopy), XRD (X-rays diffraction) and DLS (dynamic light scattering) techniques are employed. The properties of Au and Ag NPs found dependent to synthesis approach, i.e., the size, shape and morphologies, which showed a promising Catalytic, drug delivery and antimicrobial agent applications. The review is a comprehensive study for the comparison of Au and Ag NPs synthesis, properties and applications in different fields.

Biological X-ray Microanalysis: The Past, Present Practices, and Future Prospects

2001 ◽  
Vol 7 (2) ◽  
pp. 211-219 ◽  
Author(s):  
Patrick Echlin
Keyword(s):  
Electron Microscope ◽  
Low Temperature ◽  
Transmission Electron Microscope ◽  
Low Voltage ◽  
High Energy ◽  
Scanning Transmission Electron Microscope ◽  
X Ray ◽  
Ambient Temperatures ◽  
Advantages And Disadvantages ◽  
Transmission Electron

Abstract A brief description is given of the events surrounding the development of biological X-ray microanalysis during the last 30 years, with particular emphasis on the contribution made by research workers in Cambridge, UK. There then follows a broad review of some applications of biological X-ray microanalysis. A more detailed consideration is given to the main thrust of current procedures and applications that are, for convenience, considered as four different kinds of samples. Thin frozen dried sections which are analyzed at ambient temperatures in a transmission electron microscope (TEM); semithin frozen dried sections which are analyzed at low temperature in a scanning transmission electron microscope (STEM); thick frozen hydrated sections which are analyzed at low temperature in a scanning electron microscope (SEM), and bulk samples which are analyzed at low temperature in the same type of instrument. A brief outline is given of the advantages and disadvantages of performing low-voltage, low-temperature X-ray microanalysis on frozen hydrated bulk biological material. The article concludes with a consideration of alternative approaches to in situ analysis using either high-energy beams or visible and near-visible photons.

Gelatin as an ecofriendly natural polymer for preparing colloidal silver@gold nanobranches

2016 ◽  
Vol 5 (5) ◽  
Author(s):  
Phuong Phong Nguyen Thi ◽  
Dai Hai Nguyen
Keyword(s):  
Ph Value ◽  
Component Ratio ◽  
X Ray Diffraction ◽  
Ag Nps ◽  
Au Nps ◽  
X Ray ◽  
Transmission Electron ◽  
Uv Visible ◽  
The Stability ◽  
Maximum Absorption Wavelength

AbstractWe report star-shaped silver@gold (Ag@Au) nanoparticles (NPs) in gelatin suspensions for the purpose of enhancing the stability of Ag@Au NPs. In this case, Ag NPs were designed as nucleating agents, whereas gelatin was used as a protecting agent for Au development. Especially, variable gelatin concentrations were also prepared to explore its ability to increase the stability of Ag@Au NPs. The obtained samples were then characterized by UV-visible spectroscopy, transmission electron spectroscopy (TEM), X-ray diffraction, and Fourier transform infrared spectroscopy. The maximum absorption wavelength of all samples (566–580 nm) indicated that branched Ag@Au@gelatin NPs were successfully synthesized. In addition, our TEM results revealed that the size of branched Ag@Au@gelatin NPs was found to be between 20 and 45 nm as influenced by the component ratio and the pH value. These results can provide valuable insights into the improvement of Ag@Au NP stability in the presence of gelatin.

Routine Determination of X-Ray Detector Efficiencies Using Submicron Spheres of Pure Materials

1985 ◽  
Vol 43 ◽  
pp. 416-417
Author(s):  
Thomas F. Kelly
Keyword(s):  
Electron Microscope ◽  
Energy Range ◽  
Transmission Electron Microscope ◽  
Weight Fraction ◽  
Characteristic Line ◽  
X Rays ◽  
Detector Efficiency ◽  
X Ray ◽  
Transmission Electron

The purpose of this paper is to outline an approach to routine determination of x-ray detector efficiencies over the entire applicable energy range that may be used on any transmission electron microscope.BACKGROUNDThe quantification of x-ray intensities using the ratio technique can be accomplished [see, for example, 1] using a relation of the form:Here, for element A, CA is the composition in the sample as a weight fraction, kA is the x-ray generation constant (see below) which contains only sample-dependent information, eA is the detector efficiency for characteristic x-rays which contains only detector-dependent information, and lA is the measured x-ray intensity in a characteristic line.

Nonlinear Optical Properties and Cytotoxicity Studies of Fruit Extract Synthesized Silver and Gold Nanostructures

2021 ◽  
pp. 2150031
Author(s):  
E. Ramya ◽  
L. Jyothi ◽  
Narayana Rao Desai
Keyword(s):  
Optical Properties ◽  
Nonlinear Optical ◽  
Punica Granatum ◽  
Antimicrobial Activities ◽  
Nonlinear Optical Properties ◽  
Ag Nps ◽  
Au Nps ◽  
Transmission Electron ◽  
Cytotoxicity Studies ◽  
Visible Spectra

Eco-friendlybiosynthesis of silver nanoparticles (Ag NPs) and gold (Au NPs) nanoparticles by using Punica granatum and C. reticulata extracts were synthesized efficiently. Ag and Au NPs with sizes 8–10 nm and 30–40 nm were successfully synthesized and extracts serve as capping agents. Forming of NPs was confirmed through UV-visible spectra, transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectra (FTIR) studies. The effect of NPs on the luminescence of Eu(TTFA)3 and Sm(TTFA)3 complexes was investigated. Luminescence intensities of the complexes were enhanced several times in the presence of silver and get quenched due to reabsorption of Au NPs. The nonlinear optical properties of NPs were calculated using open aperture Z-scan and degenerate four-wave mixing in the femtosecond region. The toxicity and antimicrobial activities of Ag and Au NPs were studied.

IN SITU ASSEMBLY OF ZnS NANOFIBERS WITH HIGHLY ORDERED LAMELLAR MESOSTRUCTURE

2006 ◽  
Vol 05 (02n03) ◽  
pp. 245-251 ◽  
Author(s):  
JUNPING LI ◽  
YAO XU ◽  
DONG WU ◽  
YUHAN SUN
Keyword(s):  
Electron Microscope ◽  
Thermal Analyses ◽  
Blue Shift ◽  
X Rays ◽  
Energy Dispersive Analysis ◽  
Visible Absorption ◽  
X Ray ◽  
Transmission Electron ◽  
Uv Visible

ZnS nanofibers with lamellar mesostructure could be built up from in situ generated ZnS precursors via hydrothermal routes using neutral n-alkylamines as structure-directing template and ethylene diamine tetraacetic acid (EDTA) as stabilizer. The morphology and structure of the obtained products were thoroughly investigated via scanning electron microscope (SEM), energy dispersive analysis of X-rays (EDX), transmission electron microscope (TEM), X-ray powder diffraction (XRD) and thermal analyses. HRTEM and XRD results revealed that the so-produced nanofibers were lamellar mesostructure and its framework was built of crystalline wurtzite ZnS . It was also found that the distance between the layers was proportional to the chain length of the alkylamine. The UV-visible absorption spectrum showed that the nanofibers exhibited strong quantum-confined effect with a blue shift in the band gap. Finally, a probable mechanism for the assembly of the nanofibers was also proposed.

A quantitative investigation of thin specimen X-ray spectra in the TEM

1978 ◽  
Vol 36 (1) ◽  
pp. 550-551
Author(s):  
B.W. Robertson ◽  
J.N. Chapman ◽  
W.A.P. Nicholson ◽  
R.P. Ferrier
Keyword(s):  
Electron Microscope ◽  
Electron Probe ◽  
X Rays ◽  
Quantitative Investigation ◽  
Solid Materials ◽  
Thin Specimen ◽  
X Ray ◽  
Transmission Electron ◽  
Extraneous Radiation ◽  
The Continuum

In electron probe x-ray microanalysis, the observed x-ray spectra are degraded by the presence of both characteristic and bremsstrahlung x-rays from the regions of the specimen which are not under analysis and from the solid materials near the specimen. These x-rays are generated by electrons scattered from the probe by the specimen and by stray electrons originally outside the probe. The extraneous bremsstrahlung x-rays form a component of the observed continuum which is only indirectly dependent on the nature of the specimen. This effect is particularly undesirable in the analysis of thin biological specimens in the transmission electron microscope since the continuum level is commonly used in quantitative analysis as a measure of specimen mass thickness. Experiments have therefore been performed to investigate the magnitude of the extraneous radiation and to evaluate the success of attempts to reduce it. These have been detailed elsewhere (Nicholson et al. 1977).

Practical X-ray Spectrometry with Second-Generation Microcalorimeter Detectors

2012 ◽  
Vol 20 (4) ◽  
pp. 38-42 ◽  
Author(s):  
Robin Cantor ◽  
Hideo Naito
Keyword(s):  
Electron Microscope ◽  
Spatial Resolution ◽  
Energy Resolution ◽  
Semiconductor Industry ◽  
High Energy ◽  
High Energy Resolution ◽  
X Rays ◽  
X Ray ◽  
Analytical Technique ◽  
Transmission Electron

X-ray spectroscopy is a widely used and extremely sensitive analytical technique for qualitative as well as quantitative elemental analysis. Typically, high-energy-resolution X-ray spectrometers are integrated with a high-spatial-resolution scanning electron microscope (SEM) or transmission electron microscope (TEM) for X-ray microanalysis applications. The focused electron beam of the SEM or TEM excites characteristic X rays that are emitted by the sample. The integrated X-ray spectrometer can then be used to identify and quantify the elemental composition of the sample on a sub-micron length scale. This combination of energy resolution and spatial resolution makes X-ray microanalysis of great importance to the semiconductor industry.

X-ray Determination and Finite-Element Modeling of Stress in Passivated Al-0.5%Cu Lines During Thermal Cycling.

1993 ◽  
Vol 309 ◽  
Author(s):  
Paul R. Besser ◽  
Anne Sauter Mack ◽  
David Fraser ◽  
John C. Bravman
Keyword(s):  
Finite Element ◽  
Electron Microscope ◽  
Strain State ◽  
Room Temperature ◽  
Scanning Transmission Electron Microscope ◽  
X Rays ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Voltage Scanning

AbstractWe have measured the principal strain state of AI-0.5%Cu lines passivated with silicon nitride directly and used it to calculate the stress state. The stress was determined as the lines were thermally cycled from room temperature to 450°C. The general stress-temperature behavior shows good fundamental agreement with that calculated using finite-element methods, although the magnitude of the stresses measured with x-rays is less than that predicted by modeling due to stressinduced voiding in the lines. This is shown with a high voltage scanning transmission electron microscope (STEM) operated in the backscattering mode.

Transmission electron microscopy (TEM) of Earth and planetary materials: A review

2010 ◽  
Vol 74 (1) ◽  
pp. 1-27 ◽  
Author(s):  
M. R. Lee
Keyword(s):  
Electron Microscope ◽  
Electron Diffraction ◽  
Transmission Electron Microscope ◽  
Electron Spectroscopy ◽  
Atomic Resolution ◽  
Diffraction Spectrum ◽  
X Rays ◽  
X Ray ◽  
Transmission Electron ◽  
Planetary Materials

AbstractUsing high intensity beams of fast electrons, the transmission electron microscope (TEM) and scanning transmission electron microscope (STEM) enable comprehensive characterization of rocks and minerals at micrometre to sub-nanometre scales. This review outlines the ways in which samples of Earth and planetary materials can be rendered sufficiently thin for TEM and STEM work, and highlights the significant advances in site-specific preparation enabled by the focused ion beam (FIB) technique. Descriptions of the various modes of TEM and STEM imaging, electron diffraction and X-ray and electron spectroscopy are outlined, with an emphasis on new technologies that are of particular relevance to geoscientists. These include atomic-resolution Z-contrast imaging by high-angle annular dark-field STEM, electron crystallography by precession electron diffraction, spectrum mapping using X-rays and electrons, chemical imaging by energy-filtered TEM and true atomic-resolution imaging with the new generation of aberration-corrected microscopes. Despite the sophistication of modern instruments, the spatial resolution of imaging, diffraction and X-ray and electron spectroscopy work on many natural materials is likely to remain limited by structural and chemical damage to the thin samples during TEM and STEM.

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