The significance of silver nanostructures has been growing considerably, thanks to their ubiquitous presence in numerous applications, including but not limited to renewable energy, electronics, biosensors, wastewater treatment, medicine, and clinical equipment. The properties of silver nanostructures, such as size, size distribution, and morphology, are strongly dependent on synthesis process conditions such as the process type, equipment type, reagent type, precursor concentration, temperature, process duration, and pH. Physical and chemical methods have been among the most common methods to synthesize silver nanostructures; however, they possess substantial disadvantages and short-comings, especially compared to green synthesis methods. On the contrary, the number of green synthesis techniques has been increasing during the last decade and they have emerged as alternative routes towards facile and effective synthesis of silver nanostructures with different morphologies. In this review, we have initially outlined the most common and popular chemical and physical methodologies and reviewed their advantages and disadvantages. Green synthesis methodologies are then discussed in detail and their advantages over chemical and physical methods have been noted. Recent studies are then reviewed in detail and the effects of essential reaction parameters, such as temperature, pH, precursor, and reagent concentration, on silver nanostructure size and morphology are discussed. Also, green synthesis techniques used for the synthesis of one-dimensional (1D) silver nanostructures have been reviewed, and the potential of alternative green reagents for their synthesis has been discussed. Furthermore, current challenges regarding the green synthesis of 1D silver nanostructures and future direction are outlined. To sum up, we aim to show the real potential of green nanotechnology towards the synthesis of silver nanostructures with various morphologies (especially 1D ones) and the possibility of altering current techniques towards more environmentally friendly, more energy-efficient, less hazardous, simpler, and cheaper procedures.

The purposes of this work are scaled-up synthesis of silver nanowires (AgNWs), assessment of their growth mechanism and measurement of the rheological properties of nanowire suspensions suitable for screen printing conductive circuits. A polyol synthesis process was used. The morphology and microstructure at various stages of the process were characterized by scanning electron microscopy (SEM). Aqueous silver nanowire inks with dispersant and binder were formulated. The rheological behavior of the inks was characterized by Stress Sweep Step (SSS), Steady State Flow Step (SSFS), Frequency Sweep Step (FSS) and Peak Hold Step (PHS) with a parallel plate rheometer. Rheological measurements under conditions that mimic the screen printing process have been done on the conductive inks through the PHS test to assess viscoelastic properties induced by flow alignment of the wires. Finally, the effect of silver nanowires on the rheological behavior of the ink has been compared with the effect of silver threedimensional (3D) nanoparticles (AgNPs). Since most of the available commercial silver inks suitable for screen printing process are non-aqueous solvent based, a contribution of this study is formulation of an environmentally benign water based nanowire ink. Metal one-dimensional (1D) nanostructures can play a valuable role in electronic devices, and have recently gained much attention due to their unique electrical, optical, and thermal properties. Because of the high thermal and electrical conductivity of bulk silver, it is one of the most promising metal nanowire materials.1-8 Silver nanowires hold promise as the conductive material in conductive inks suitable for screen printing. 8,[10][11][12][13][14][15] There are several methods to synthesize silver nanowires including the polyol process, hydrothermal synthesis, wet chemical process and irradiation photo reduction. Among these, the polyol process is simple and inexpensive, and provides a relatively high yield. 6 The polyol process proceeds by chemical reduction of silver ion in the presence of a polymeric surfactant. Poly(Vinyl Pyrrolidone) (PVP) acts to cap the (100) facet leading to uniaxial elongation of the initially formed silver seeds. In this process a trace amount of suitable salt can facilitate the growth of the initially formed silver seeds to the desired shape. The ethylene glycol functions as both solvent and reducing agent. [1][2][3] Various methods of printing have been used for the fabrication of printed circuits. Among these, screen printing is a rapid and inexpensive process.9 Thin printed circuits are applied in many technologies such as solar panels, flexible circuitries, and touch screens. [15][16][17][18][19][20][21][22] In screen printing, the ink is forced through a patterned screen onto a substrate. The printed pattern characteristics depend critically on the rheological properties of the ink.8 Strong shear thinning behavior permits charging of the ink at low shear onto the screen, followed by printing through the screen at high shear. Reco...

The objective of this study is investigation of the effects of process parameters in polyol synthesis of silver nanowires (AgNWs) on the nanostructure morphology and silver nanowire yield for the purpose of process optimization. The AgNWs were synthesized in a batch polyol salt-mediated surfactant-assisted process and characterized by scanning electron microscopy (SEM). The effects of several parameters on morphology and yield, including reagent concentration and molecular weight (MW), temperature, reagent solution preparation, and stirring rate were investigated. Based on this parametric study, the important variables were identified. A design of experiment (DoE) was applied to this set of variables to determine their simultaneous effect on nanowire morphology and yield. An optimum set of parameters was determined and demonstrated to provide very high yield and high length to diameter ratio.

Biomolecules are increasingly attractive templates for the synthesis of functional nanomaterials. Chief among them is the plant tobacco mosaic virus (TMV) due to its high aspect ratio, narrow size distribution, diverse biochemical functionalities presented on the surface, and compatibility with a number of chemical conjugations. These properties are also easily manipulated by genetic modification to enable the synthesis of a range of metallic and non-metallic nanomaterials for diverse applications. This article reviews the characteristics of TMV and related viruses, and their virus-like particle (VLP) derivatives, and how these may be manipulated to extend their use and function. A focus of recent efforts has been on greater understanding and control of the self-assembly processes that drive biotemplate formation. How these features have been exploited in engineering applications such as, sensing, catalysis, and energy storage are briefly outlined. While control of VLP surface features is well-established, fewer tools exist to control VLP self-assembly, which limits efforts to control template uniformity and synthesis of certain templated nanomaterials. However, emerging advances in synthetic biology, machine learning, and other fields promise to accelerate efforts to control template uniformity and nanomaterial synthesis enabling more widescale industrial use of VLP-based biotemplates.