Synthesis Of Silver Nanowires Research Articles

Rapid and uniform synthesis of silver nanowires via rice-shaped silver nucleant

In this work, we demonstrate the synthesis of silver nanowires via a nonaqueous method that employs ethylene glycol to reduce silver nitrate into metallic silver which deposited on the pre-synthesized silver nucleants. The silver nucleants with different morphologies were synthesized by adjusting the reaction temperature and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and ultraviolet–visible spectroscopy (UV–vis). The results indicated that the silver nucleants with dendritic and nanorice morphologies could be prepared under the temperature of 313K, 353K, and 393K, respectively. Specially, it was demonstrated for the first time that the silver nanowires with high aspect ratio and uniformity could be synthesized rapidly via the silver nucleant with the nanorice morphology.

A Rapid Synthesis of High Aspect Ratio Silver Nanowires for High‐Performance Transparent Electrodes

AbstractA rapid, simple and cost‐effective polyol method has been developed for the synthesis of silver nanowires with high aspect ratio and high purity. The aspect ratios of the silver nanowires as high as ca. 1000 (average length 40 µm and some even as long as 80 µm, diameter 50–100 nm) were obtained via optimizing the reaction conditions. Transparent electrodes with excellent optoelectronic performances (optical transmittance of 90%, sheet resistance of 23.2 Ω/□ and optical transmittance of 87%, sheet resistance of 19.7 Ω/□) comparable to commercial ITO were fabricated via simple spin coating the resulting silver nanowires onto the glass substrates. The high optoelectronic performances and the facile all‐solution process of the as‐prepared transparent electrodes render them rather promising candidates for use in cost‐effective large‐area optoelectronic devices.

Polyol Synthesis of Silver Nanowires by Heterogeneous Nucleation; Mechanistic Aspects Influencing Nanowire Diameter and Length

The growth of silver nanowires via polyol synthesis is studied by employing AgCl nanocubes of varying size as the heterogeneous nucleants. The final mean silver nanowire diameter is found to be independent of the size of the heterogeneous nucleant, showing that the diameter is not significantly influenced by the nucleation event. Kinetic studies determine that nanowire diameter, length, and aspect ratio grow in parallel to one another and with the extent of the Ag+ reduction reaction, demonstrating that growth is limited by the reduction rate. The results are interpreted to support nanowire growth by a surface-catalyzed reduction process occurring on all nanowire surfaces and to exclude nanoparticle aggregation or Ostwald ripening as a primary components of the growth mechanism.

One pot rapid synthesis of silver nanowires using NaCl assisted glycerol mediated polyol process

We report, one pot rapid synthesis of silver nanostructures from AgNO3 through glycerol mediated polyol process with the assistance of polyvinyl pyrrolidone (PVP) and NaCl. The growth of silver nanostructures was studied by monitoring changes in the position of localized surface plasmon resonance band using the UV-vis-NIR spectroscopy. Morphology of the silver nanostructures was indentified using the scanning electron microscope which confirms the formation of nanoparticle, V-shaped and linear silver nanowires. The favorable temperature and NaCl concentration to obtain nanoparticles, V-shaped and linear silver nanowires are optimized. 5 mM NaCl at 250°C produced 55 — 65 nm width, 4 μm long silver nanowires along [100] in PVP added glycerol medium within 25 minutes.

Synthesis of silver nanowires as a SERS substrate for the detection of pesticide thiram

Silver nanowires with uniform diameters have been synthesized via the rapid sulfide mediated polyol method. The morphology, structure, and properties of as-prepared samples are characterized by UV–Visible spectroscopy, field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD), respectively. The mechanism of as-prepared Ag nanowires is provided and discussed. Moreover, as-prepared Ag nanowires are used as a Surface-Enhanced Raman Scattering (SERS) substrate to detect thiram pesticide. The results show that this substrate based on Ag nanowires exhibits high sensitivity and reproducibility for the thiram detection.

The effects of physicochemical parameters on the synthesis of silver nanowires via polyol method

The potential applications of one-dimensional nanostructured materials widely depend on their shape and size. This paper deals with a method for synthesizing and characterizing silver nanowires through an organic solution. The so-called polyol method was used to synthesize silver nanowires in which ethylene glycol was used as both media and the reducing agent. Adequate CuCl2/ethylene glycol solution is used to prohibit chemical etching by the oxygen on nanowires surfaces. The effects of CuCl2 concentration and the addition rate of AgNO3 were examined. It was revealed that by optimizing the parameters, silver nanowires with aspect ratios of up to 32 are accessible. To characterize the structure and morphology of nanowires, X-ray powder diffraction, UV–Vis spectroscopy, scanning electron microscopy and atomic force microscopy were used.

Preparation of Silver Nanowires via a Rapid, Scalable and Green Pathway

Rapid synthesis of silver nanowires (Ag NWs) with high quality and a broad processing window is challenging because of the low selectivity of the formation of multiply twinned particles at the nucleation stage for subsequent Ag NWs growth. Herein we report a systematic study of the water-involved heterogeneous nucleation of Ag NWs with high rate (less than 20 min) in a simple and scalable preparation method. Using glycerol as a reducing agent and a solvent with a high boiling point, the reaction is rapidly heated to 210 °C in air to synthesize Ag NWs with a very high yield in gram level. It is noted that the addition of a small dose of water plays a key role for obtaining highly pure Ag NWs in high yield, and the optimal water/glycerol ratio is 0.25%. After investigating a series of forming factors including reaction temperature and dose of catalysts, the formation kinetics and mechanism of the Ag NWs are proposed. Compared to other preparation methods, our strategy is simple and reproducible. These Ag NWs show a strong Raman enhancement effect for organic molecules on their surface.

One step synthesis of silver nanowires used in preparation of conductive silver paste

For mass preparation of conductive silver paste, a convenient approach to synthesize silver nanowires (Ag NWs) is presented. Monodisperse Ag NWs with ca. 40 nm in diameter and over 10 μm in length were successfully obtained in high yield only by heating a mixture of AgNO3, poly(vinyl pyrrolidone), ethylene glycol and HCl prepared previously. This method not only simplifies the conventional polyol process but also extremely improves its repeatability. More important, the patterns fabricated with the Ag NWs naturally have a high conductivity, up to ca. 13 % of bulk silver, due to the cross-linked network structure formed by accumulation of nanowires. The conductivity even can be improved to 41 % of bulk silver conductivity through a chemical sintering at room temperature, which makes us believe that the Ag NWs could be broadly applied in preparation of conductive paste.

Glycerol mediated synthesis of silver nanowires for room temperature ammonia vapor sensing

Silver nanowires were synthesized by glycerol mediated process with the assistance of polyvinyl pyrrolidone. The grown nanowires have preferential orientation of [111]. Purified silver nanowires showed the absorptions at 400 and 352nm in UV–vis-NIR spectrum. The average width and length of the purified silver nanowires were measured as 60nm and 7μm, respectively, using the scanning electron microscopy. The ammonia vapor sensitivity of the dispersed silver nanowires coated on cladding removed polymethyl methacrylate fiber was calculated to be 0.17 counts/ppm at room temperature. The response and recovery times were found to be 70 and 80min, respectively, for 500ppm ammonia vapor concentration in the absence of carrier gas.

Characterization of Micro- and Nanoscale Silver Wires Synthesized Using a Single-Replacement Reaction between Sputtered Copper Metal and Dilute Silver Nitrate Solutions

This paper describes an experiment developed to provide students enrolled in introductory nanotechnology and introductory chemistry courses with an opportunity to synthesize silver nanowires using a bottom-up nanofabrication technique. The reaction between copper metal sputter coated on silicon dioxide and a dilute silver nitrate solution is used to create the nanowires. Included in this experiment is a characterization component allowing students to analyze the nanowires using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Microscale silver wires are also produced in the reaction, making it possible for students to utilize optical microscopy, in addition to AFM and SEM, for silver wire characterization. The silver nanowire synthesis reported in this paper does not require the use of nanoporous templates or hazardous purification steps to liberate wires from template confinement.

Investigating the effect of capping agent PVP on the synthesis of silver nanowires by polyol method and its application as flexible transparent conducting electrode

In this report, we present a rapid and efficient polyol method - the solution-phase approach for the large scale synthesis of silver nanowires with diameters in the range of 40 - 50 nm, and lengths up to 20 μm. Although the polyol process is a popular method of preparing metal nanostructures, so far most of the published works mainly focused on the synthesis process regardless of amount of surfactants. In this article, we successfully synthesized large-scale uniform silver nanowires with high aspect ratios by introducing the long-chain PVP (MW = 58 000) and investigated the effect of the amount of PVP on the synthesis of Ag nanowires by studying their morphologies, structures and optical properties. The dependency of nanowire morphology and aspect ratio on synthesis parameters was shown via SEM images. The diameter of nanowires decreased when the molar ratio of PVP to silver nitrate was increased. Further more, the molar ratios decided the morphology (particle, rod or wire) of the Silve solution. Synthesized silver nanowires were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). This aqueous dispersions of silver nanowires were used to prepare thin, flexible, transparent, conducting films on polyethylene terephthalate substrate (PET) by spraying method. The prepared silver nanowire films on PET substrate had a transparency of 82% and sheet resistance of 10 Ω/□.

Effect of AgNO3 addition rate on aspect ratio of CuCl2–mediated synthesized silver nanowires using response surface methodology

Nanomaterials have size-dependant properties which are important in their field of application. In this study response surface methodology (RSM) was successfully used to consider the effects of AgNO3 addition rate and Cl− concentration on the aspect ratio of silver nanowires synthesized via polyol method; the most commonly applied method for synthesizing metallic nanoparticles. Moreover, a suitable model for the relationship between the factors (AgNO3 addition rate and Cl− concentration) and the response (aspect ratio) was statistically developed. Based on the statistical analysis, it was shown that the first order of these two factors have the same significance on the aspect ratio of silver nanowires; while, the second order term of AgNO3 addition rate has a much higher effect on the response compared to Cl− concentration. Furthermore, the interaction between these two factors was statistically significant. It was found that when the concentration of Cl− is lower than 1.05mM, the aspect ratio of formed silver nanowires is remarkably low regardless of AgNO3 addition rate in the studied range. Moreover, by the use of proposed second order polynomial model, the optimum values of the factors were estimated for obtaining nanowires with fairly high aspect ratio (∼100).

Synthesis and application of graphene–silver nanowires composite for ammonia gas sensing

Graphene, consisting of a single carbon layer in a two-dimensional (2D) lattice, has been a promising material for application to nanoelectrical devices in recent years. In this study we report the development of a useful ammonia (NH3) gas sensor based on graphene–silver nanowires ‘composite’ with planar electrode structure. The basic strategy involves three steps: (i) preparation of graphene oxide (GO) by modified Hummers method; (ii) synthesis of silver nanowires by polyol method; and (iii) preparation of graphene and silver nanowires on two electrodes using spin and spray-coating of precursor solutions, respectively. Exposure of this sensor to NH3 induces a reversible resistance change at room temperature that is as large as ΔR/R0 ∼ 28% and this sensitivity is eight times larger than the sensitivity of the ‘intrinsic’ graphene based NH3 gas sensor (ΔR/R0 ∼ 3,5%). Their responses and the recovery times go down to ∼200 and ∼60 s, respectively. Because graphene synthesized by chemical methods has many defects and small sheets, it cannot be perfectly used for gas sensor or for nanoelectrical devices. The silver nanowires are applied to play the role of small bridges connecting many graphene islands together to improve electrical properties of graphene/silver nanowires composite and result in higher NH3 gas sensitivity.

Synthesis of Silver Nanowires by 5-Hydroxy-Tryptophan

Silver nanowires in large quantities can be obtained by 5-hydroxy-L-tryptophan through a simple method in the absence of a surfactant and seed. The influences of different experimental parameters on the morphologies of silver nanoproducts in such an environmentally friendly synthesis were investigated. Different molar ratio of reactants which can results different size and shape of silver nanoparticles. The high temperature, the acid or alkaline condition is not to facilitate formation of the nanowires. This simple and eco-friendly preparation method of silver nanowires can decrease the synthetic cost and broaden the research and application areas of silver nanowires.

Rapid synthesis of pentagonal silver nanowires with diameter-dependent tensile yield strength

We synthesize silver nanowires (NWs) with pentagonal cross sections via a facile and rapid microwave-assisted polyol method in the presence of polyvinylpyrrolidone (PVP) and sodium sulfide (Na2S). The synthesis does not use templates and needs only 2.5 min, which is 570 times faster than solvothermal preparation at 100 °C. The pentagonal Ag NWs grow along the <110> direction and reach lengths between 10 and 30 μm. Adjusting Na2S concentration controls the wire diameters in a wide range from 60 to 480 nm. PVP and microwave irradiation both ensure the cross sections' pentagonal shape even at large diameters. We use different microwave irradiation times to investigate the morphology's evolution and to support the discussion of growth mechanisms. The electrical conductivity was measured in situ inside a transmission electron microscope. Their resistivity is diameter dependent and comparable to that of Ag NWs with round cross sections. Ultrasound fracturing analysis determined the NWs' tensile yield strengths, which is also diameter dependent and maximal around 220 nm.

Photostability of photosynthetic complexes coupled to silver nanowires

We investigate the influence of plasmonic excitations in silver nanowires upon the photostability of photosynthetic complex placed at their vicinity. Strong interaction between the two nanostructures is evident through increase of the fluorescence intensity of the photosynthetic complexes close to the nanowires as compared to uncoupled ones and shortening of the fluorescence lifetime. Analysis of movies collected using a wide-field fluorescence microscope with respect to temporal intensity variations for photosynthetic complexes located along and at the ends of the nanowires, indicate that the photostability is unaffected by the interaction with plasmonic excitations in metallic nanoparticles. Therefore, we conclude that in the case of studied hybrid nanostructures coupling with metallic nanoparticles results in higher number of photons emitted from chlorophyll molecules. Full Text: PDF References R.E. Blankenship, Wiley-Blackwell, ISBN: 978-0-632-04321-7 (2002). Ł. Bujak, N. Czechowski, D. Piatkowski, R. Litvin, S. Mackowski, T.H.P. Brotosudarmo, R.J. Cogdell, S. Pichler, W. Heiss, "Fluorescence enhancement of light-harvesting complex 2 from purple bacteria coupled to spherical gold nanoparticles", Appl. Phys. Lett. 99, 173701 (2011). CrossRef N. Czechowski, P. Nyga, M.K. Schmidt, T.H.P. Brotosudarmo, H. Scheer, D. Piatkowski, S. Mackowski, "Absorption Enhancement in Peridinin&ndash;Chlorophyll&ndash;Protein Light-Harvesting Complexes Coupled to Semicontinuous Silver Film", Plasmonics 7, 115 (2012). CrossRef J.B. Nieder, R. Bittl, M. Brecht, "Fluorescence Studies into the Effect of Plasmonic Interactions on Protein Function", Angew. Chem. Int. Ed. 49, 10217 (2010). CrossRef A. O. Govorov, I. Carmeli, "Hybrid Structures Composed of Photosynthetic System and Metal Nanoparticles:&thinsp; Plasmon Enhancement Effect", Nano Letters 7, 620 (2007). CrossRef M. Olejnik, B. Krajnik, D. Kowalska, M. Twardowska, N. Czechowski, E. Hofmann, S. Mackowski, "Imaging of fluorescence enhancement in photosynthetic complexes coupled to silver nanowires", Appl. Phys. Lett. 102, 083703/1 (2013). CrossRef P. Anger, P. Bharadwaj, L. Novotny, "Enhancement and Quenching of Single-Molecule Fluorescence", Phys. Rev. Lett. 96, 113002 (2006). CrossRef J.R. Lakowicz, "Radiative Decay Engineering: Biophysical and Biomedical Applications", Analytical Biochemistry 298(1), 1 (2001). CrossRef K. Ray, R. Badugu, J.R. Lakowicz, "Metal-Enhanced Fluorescence from CdTe Nanocrystals:&thinsp; A Single-Molecule Fluorescence Study", J. Am. Chem. Soc. 128, 8998 (2006). CrossRef S. Mackowski, S. W&ouml;rmke, A.J. Maier, T.H.P. Brotosudarmo, H. Harutyunyan, A. Hartschuh, A.O. Govorov, H. Scheer, C. Br&auml;uchle, "Metal-Enhanced Fluorescence of Chlorophylls in Single Light-Harvesting Complexes", Nano Letters 8, 558 (2008). CrossRef A.D. Ferguson, E. Hofmann, J. W. Coulton, K. Diederichs, W. Welte, "Siderophore-Mediated Iron Transport: Crystal Structure of FhuA with Bound Lipopolysaccharide", Science 282, 2215 (1998). CrossRef K.E. Korte, S.E. Skrabalak, Y. Xia, "Rapid synthesis of silver nanowires through a CuCl- or CuCl 2 -mediated polyol process", J. Mater. Chem. 18, 437 (2008). CrossRef T.H.P. Brotosudarmo, E. Hofmann, R.G. Hiller, S. W&ouml;rmke, S. Mackowski, A. Zumbusch, C. Br&auml;uchle, H. Scheer, "Peridinin&ndash;chlorophyll&ndash;protein reconstituted with chlorophyll mixtures: Preparation, bulk and single molecule spectroscopy", FEBS Letters 580, 5257 (2006). CrossRef

Rapid Synthesis of Silver Nanowires and Network Structures under Cuprous Oxide Nanospheres and Application in Surface-Enhanced Raman Scattering

Crystalline silver nanowires, with diameters of 50–500 nm and lengths up to tens of micrometers, have been successfully synthesized by a simple wet chemical route by using cuprous oxide nanospheres as a reductant and directional agent. The products are characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and UV–vis absorption spectroscopy. The two-dimensional netlike nanostructure is composed of several silver nanowires. The possible mechanism for the formation of silver nanowires is discussed. It is found that the architecture of silver crystals is drastically influenced by the concentration of the precursors and the reaction temperature. The experimental results reveal that the Cu2O nanospheres might play the two roles during the growth process of silver nanowires. Except for a reducing agent, Cu2O nanospheres act as a growth substrate to induce the formation of silver nanowires and a two-dimensional netlike nanostructure. Furthermore, the obtained two-dimensional netlike silver nanostructure can be used as surface-enhanced Raman scattering (SERS) substrates with high SERS activity and stability for detecting Rhodamine 6G (R6G) molecules. The analytical enhancement factor on the two-dimensional netlike silver nanostructure substrate is about 8 × 1010. Compared with other morphologies of silver substrates, it is found that the two-dimensional netlike silver nanowires exhibit the highest SERS sensitivity. Hence, SERS substrates of the two-dimensional netlike silver nanowires described in this work have potential applications in chemical and biological analysis as well as medical detection.

Silver Chloride as a Heterogeneous Nucleant for the Growth of Silver Nanowires

Various additives are employed in the polyol synthesis of silver nanowires (Ag NWs), which are typically halide salts such as NaCl. A variety of mechanistic roles have been suggested for these additives. We now show that the early addition of NaCl in the polyol synthesis of Ag NWs from AgNO3 in ethylene glycol results in the rapid formation of AgCl nanocubes, which induce the heterogeneous nucleation of metallic Ag upon their surfaces. Ag NWs subsequently grow from these nucleation sites. The conclusions are supported by studies using ex situ generated AgCl nanocubes.

Silver Nanowires: Uniformly Interconnected Silver‐Nanowire Networks for Transparent Film Heaters (Adv. Funct. Mater. 10/2013)

By synthesizing silver nanowires with high aspect ratio and optimizing the nanowire network quality, highly transparent and conductive films are obtained on a large scale. These are explored as electrodes for flexible film heaters. On page 1250, Kwang S. Suh and co-workers report that the film heater based on a uniformly interconnected silver nanowire network shows an efficient heating at low input voltages.

Transparent conductive film by large area roll-to-roll processing

Sputtered indium tin oxide (ITO) coating on polyethylene terephthalate film has been used as the substrate for roll-to-roll fabrication of large area printed electronics devices, but it is expensive and could be cracked when bending, limiting its applications. Transparent conductive (TC) electrode made by roll-to-roll coating of transparent conductive ink on flexible substrate is an alternative, but both the ink material and the control of the coating quality are very crucial. The major challenges are the coating performance, coating uniformity and defect control during roll-to-roll processing. In this paper, we report the chemical synthesis of silver nanowires in preferred shape and size, the surface modification of the Ag nanowires for better dispersion into the commercial Poly(3,4-ethylenedioxythiophene) Poly(styrenesulfonate) (PEDOT:PSS) conductive polymer ink, and the controlled roll-to-roll coating process on flexible polyethylene terephthalate substrate by a one meter web-width roll-to-roll slot die coating system. We obtained high uniformity PEDOT:PSS coating with optical transmission higher than 80% and sheet resistance lower than 100Ω/square, and silver containing coating with sheet resistance below 40Ω/square and maintained optical transmittance. The slot die coating mechanism is investigated and the influencing factors for coating uniformity and defect are defined. The coated transparent conductive film has the same properties as the sputtered ITO and has been used as the TC electrode for printed lighting, whose performance has been proven by standard weathering test for 1000h.