Silver nanowire, formation

Figure 14.11. Schematic representation of the DNA-pectin templated silver nanowire formation between two interdigitated electrodes.

Sloan J, Wright DM, Bailey S, Brown G, York APE, Coleman KS, Green MLH, Hutchison JL, Woo H-G. Capillarity and silver nanowire formation observed in single walled carbon nanotubes. Chem Commun 1999 699-700. 

Figure 12.10 Formation of a silver nanowire inside a channel of a short-chain diphenylalanine peptide tube.

The synthesis of conductive metallic nanowires that bridged two microelectrodes separated by a gap of 12-16 im was demonstrated by the growth of a silver nanowire on a DNA template that bridged the gap (Fig. 12.26).92 Short thiolated nucleic acids (12 bases long) were attached to the microelectrodes, and these acted as sticky ends for the hybridization of /.-DNA that bridged the gap. The association of Ag+ to the phosphate groups of the template, followed by their reduction with hydroquinone under basic conditions, resulted in the formation of Ag° nanoclusters on the DNA template. The subsequent enlargement of the Ag° seeds by the catalytic reduction of Ag+ by hydroquinone, under acidic conditions, yielded continuous Ag nanowires with a width of ca. lOOnm. The nanowires revealed nonlinear I—V... 

Giersig, M., Pastoriza-Santos, I. and Liz-Marz, L. M. (2004). Evidence of an aggregative mechanism during the formation of silver nanowires in N,N-dimethylformamide. J. Mater. Chem. 14 607-610. 

As was mentioned earlier, CHQ nanotube arrays can be utilized in promising templates for nanosynthesis. Redox reaction of the nanotube in the presence of silver nitrate leads to the formation of silver nanowire arrays in the pores (pore size of 8 X 8 A ) of the CHQ nanotube. The wires exist as uniformly oriented 3D arrays of ultrahigh density. The driving force for the formation of these nanowires is the free energy gain due to the reduction-oxidation process [154,155]. It was experimentally observed that the resulting nanowire is comprised of four dumbbells, each of which contains two silver atoms, superimposed on one another, and crisscrossed in their length. 

Three major breakthroughs in process technology have recently been made. These processes facilitate the growth from a liquid phase. They inciude the formation of (1) InP, InAs and GaAs whiskers [18] from other organic soivents by a soiution-iiquid-soiid phase transformation, (2) short carbon fibers from liquid pitch melts by centrifuging [19], and (3) silver nanowires by a novel self-assembly process [71]. Micro- and nanopillars (or micro-and nanocolumns) are a new class of short inorganic fibers. They are... 

Kim s group has also employed caUxarenes in the formation of nanotubes that have been used as templates for the formation of silver nanowires. CaIix[4]hydroquinone subunits self-assemble to give rosettes due to the formation of hydrogen bonds between the phenoUc groups. The low oxidation potential for hydroquinones is employed to induce the formation of silver wires with a diameter of 0.4 nm when the nanotubes are formed in the presence of silver salts. 

Kim TY, Kim WJ, Hong SH, Kim JE, Suh KS (2009) lonic-liquid-assisted formation of silver nanowires. Angew Chem Int Ed Engl 48(21 ) 3806-3809... 

Zhou Y., Yu S.H., Cui X.P., Wang C.Y., Chen Z.Y. Formation of silver nanowires by a novel solid-liquid phase arc discharge method. Chem. Mater. 1999a 11 545-546 Zhou Y., Yu S.H., Wang C.Y., Li X.G., Zhu Y.R., Chen Z.Y. A novel ultraviolet irradiation photoreduction technique for the preparation of single-crystal Ag nanorods and Ag dendrites. Adv. Mater. 1999b 11(10) 850-852... 

Peng Z, You H, Yang H (2010) Composition-dependent formation of platinum silver nanowires. ACS Nano 4 1501... 

Within the following sections we will discuss fundamental aspects of nanoparticle processing including the most important steps of characterization, particle formation, stabilization and post processing to end up with some general conclusions for a future process design. As model materials we use technically relevant semiconductor nanoparticles, so-called quantum dots (QDs) with direct band gap (ZnO, manganese doped ZnS and PbS(e)) and silver nanowires which have been proven to be excellent transparent electrodes for thin film solar cells [27]. 

Porous anodic aluminum oxide (AAO) which characterized by a closely packed regular array of columnar cells is well-established and widely-used material for formation of nanostructures for SERS [2,3]. Particularly, promising SERS-active substrates were prepared by vacuum deposition of silver onto commercially available alumina filters with open pores of 200-300 nm diameters [4], Nanowires and nanorods have been fabricated by filling the AAO pores with transition- or noble-metals. However, due to multistage procedure these nanoarrays being sensitive are rather complicated in fabrication. 

As illustrated in Scheme 3.14, Ag nanoparticles were prepared within the tubes via a reaction with Ag[PF6]. We found that partial preoxidation of the PFS domains with an organic oxidant such as tris(4-bromophenyl)aminium hexachloroantimonate is a key step for the efficient formation of one-dimensional arrays of silver nanoparticles confined within the nanotubes (Figure 3.10).50 Further attempts to synthesize metal nanowires through this encapsulation method are currently in progress. 

Irradiation by ionizing radiation able to penetrate into a zeolite material exchanged by metal ions allows to generate metal atoms and clusters in situ in the cavities.The observation of irradiated faujasite (Na-Y zeolite) by optical absorption spectroscopy at increasing doses and at low silver content demonstrates the formation of two bands at 265 and 305 nm which have been assigned to the charged trimer Agj ". Then, the ESR observation after a dehydration step indicates the reduction of this species into Agj . Irradiation of HjPtClg solution included in mesoporous channels of molecular sieves induces nanowires of platinum. ... 

---