Size-Controlled Synthesis of Colloidal Silver Nanoparticles Based on Mechanistic Understanding (original) (raw)
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Synthesis and characterization of size- and shape-controlled silver nanoparticles
Physical Sciences Reviews, 2018
Silver nanoparticles (AgNPs) have application potential in diverse areas ranging from wound healing to catalysis and sensing. The possibility for optimizing the physical, chemical and optical properties for an application by tailoring the shape and size of silver nanoparticles has motived much research on methods for synthesis of size- and shape-controlled AgNPs. The shape and size of AgNPs are reported to vary depending on choice of the Ag precursor salt, reducing agent, stabilizing agent and on the synthesis technique used. This chapter provides a detailed review on various synthesis approaches that may be used for synthesis of AgNPs of desired size and shape. Silver nanoparticles may be synthesized using diverse routes, including, physical, chemical, photochemical, biological and microwave -based techniques. Synthesis of AgNPs of diverse shapes, such as, nanospheres, nanorods, nanobars, nanoprisms, decahedral nanoparticles and triangular bipyramids is also discussed for chemical-...
Single step morphology-controlled synthesis of silver nanoparticles
Silver nanoparticles having different size and plasmon resonances were synthesized through a single step aqueous based method. The current procedure was based on the reduction of silver ions by ascorbic acid in the presence of sodiumborohydride and trisodium citrate. Triangular colloidal nanoparticles having different plasmon resonances (and hence different size and colours) were synthesized by varying only the concentration of ascorbic acid. These nanoparticles were found to be stable without using any surfactants or polymers. This study revealed a strong correlation between particle growth and concentration of constituent chemicals. Crystallinity and phase purity of the silver samples were investigated through powder X-ray diffraction studies (XRD). Absorption spectra of various silver particles were recorded using UV/Vis/NIR spectrometer. Morphological analysis was performed using transmission electron microscopy (TEM) and average edge lengths of nanoparticles were also calculated.
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Preparation of silver nanoparticles with controlled particle size
Procedia Chemistry, 2009
Silver colloids show different colors due to light absorption and scattering in the visible region based on plasmon resonance. The resonance wavelength depends on particle size and shape. Here we report chemical reduction methods for preparation of silver nanoparticles exhibiting multicolor in aqueous solutions. Depending on chemical conditions the obtained nanoparticles are differen In order to investigate the relationship between size, stability and color of silver colloids we obtained silver nanoparticles in aqueous solutions using different reducing agents. The effect of polyvinyl pyrrolidone (PVP) and polyvinyl alcohol (PVA) on stabilization of obtained silver colloids was investigated. We have also studied the effect of silver precursor and its concentration on the formation of stable silver colloids. UV-VIS spectrum for silver colloids contains a strong plasmon band near 410 nm, which confirms silver ions reduction to Ag° in the aqueous phase. The formation of metal silver was also confirmed by powder X-ray diffraction (XRD) analysis. The diameter size of silver nanoparticles was in the range from 5 nm to 100 nm
Influence of Reagents on the Synthesis Process and Shape of Silver Nanoparticles
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The aim of this study was to prepare the silver nanoparticles (AgNPs) via chemical reduction and analyze the impact of used reduction agents: sodium borohydride (NaBH4), trisodium citrate (TSC), polyvinylpyrrolidone (PVP), and hydrogen peroxide (H2O2) on the reduction rate of Ag+ ions to Ag0, and on nanoparticles shape. It was proven that combinations of reduction agents dramatically influence the synthesis rate of AgNPs and the color of solutions, which depends on the shape and size of nanoparticles. NaBH4, TSC, and PVP showed good reduction power. In particular, TSC proved to be a key factor influencing the shape of AgNPs. The shape of nanoparticles influences the color of colloidal solutions. Yellow solutions, where UV-vis absorbance maxima (ABSmax) are in the wavelength interval 380–420 nm, contain spherical particles with a mean size of 25 nm, whereas the blue shift of ABSmax to wavelengths higher than 750 nm indicate the presence of triangular nanoparticles (size interval 18–1...
Journal of Cluster Science, 2016
There is profound interest in synthesis of nanoparticles having exceptional control over the shape and mean size distribution which is prime goal of the nanotechnology. In this research, an eco-friendly approach has been adopted to synthesize silver nanoparticles of mean size 24-33 nm using root bark extract of Berberis lycium Royle. These silver nanoparticles were characterized by UV-Visible spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy and atomic absorption spectroscopy. This experimental investigation has been carried out systemically to perceive the influences of concentrations of bark extract and AgNO 3 , temperature and pH on the morphology and mean size distribution of the evolved nanoparticles. The reduction mechanism of silver ions which lead to formation of nanoparticles has been studied and realized that alkaloids, flavonoids and sugars are predominantly involved in the growth process. This green approach has been anticipated to be facile and cost-effective for having better morphologically and mean size distribution control of silver nanoparticles and can transform the future of nano science and technology.
Synthesis and characterization of Silver Nanoparticles
ABSTRACT: Different methods may be used to produce nanoparticles, for instance in 1951 Turkevich and co-workers proposed that gold nanoparticles can be produced from the reaction of trisodum citrate, which acts as a stabilizing and reducing agent, with chloroauric acid, the source of gold nanoparticles. By changing chloroauric acid to silver nitrate, silver nanoparticles can instead be produced. Despite being widely used, there is a debate in the literature on the way the reagents and conditions, used for the Turkevich method, affect the size and shape of the silver nanoparticles produced. In view of this, silver nanoparticles have been synthesised through the Turkevich method using different reaction conditions, namely the reaction temperature and concentration of sodium citrate used. Characterisation techniques were then used to determine the size and shape of the silver nanoparticles produced. It was found that increasing the temperature increased the size of the nanoparticles through SEM, although DLS showed the opposite trend. Furthermore, at higher temperatures the formation of rod-like particles could be observed, as opposed to more spherical particles at lower temperatures.
Controlled synthesis of colloidal nanoparticles in organic solutions is among the most intensely studied topics in nanoscience because of the intrinsic advantages in terms of high yield and high uniformity in comparison with aqueous synthesis. However, systematic studies on the formation mechanism of nanoparticles with precisely tailored physical parameters are barely reported. In this tutorial review, we take the synthesis of different Ag nanoparticles as an example to rule out the general principles for controlling the nucleation process involved in the formation of colloidal Ag nanoparticles in organic solutions, which enables the synthesis of high-quality nanoparticles.
Synthetic Routes for the Preparation of Silver Nanoparticles: A Mechanistic Perspective
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In this chapter, we revise some of the most relevant and widely use synthetic routes available for the preparation of metallic silver nanoparticles. Particular emphasis has been put in the rationale involved in the formation of the nanostructures, from the early metallic silver atoms formation, passing by atoms nucleation and concluding in the growth of silver nanostructures. We hope the reader will find in this chapter a valuable tool to better understand the relevance of the experimental conditions in the resulting silver nanoparticle size, shape and overall properties.