Nanowires electrochemically synthesized

Figure 1.16 SEM of electrochemically synthesized [a] PANI nanowires and [b] composite nanowires in AAO membranes [etched with NaOH] [187]. Reproduced by kind permission from the publisher.

PPy nanotubes and nanowires can be also electrochemically synthesized through nanoporous AAO template in ionic liquids... 

Cobalt-PPy-cobalt nanowire was electrochemically synthesized inside alumina membrane and the field-effect transistors were fabricated by patterning a gate on one side of the cobalt-PPy-cobalt nanowire [409]. The measiued output and transfer characteristics are as good as or better than PPy film field-effect transistors. The gain of the nanowire field-effect transistors could be controlled with successive electrochemical doping of the PPy segment. 

TouriUon, G. Pontonnier, L. Levy, J. P Langlais, V. Electrochemically synthesized Co and Fe nanowires and nanotubes. Electrochem. Solid State Lett. 2000, 3, 20-23. 

Voss, T., C. Bekeny, J. Gutowski et al. 2009. Localized versus delocalized states Photoluminescence from electrochemically synthesized ZnO nanowires. J. Appl. Phys. 106 054304. 

The synthesis of Pt metal nanowires and nanotubes electrochemically deposited through nanoporous membranes was reported by Ichikawa (2000). Palladium deposits with high specific surface areas, up to 50 m g", have been synthesized by Tsirlina et al. (2002) from palladium chloride solutions with additions of polyethylene glycol and polyvinyl pyrrolidone. Details of the globular structine of the deposits depend on the polymer additives. A comparison with electrochemically determined true surface areas demonstrates the coalescence of nanoparticles. Wang et al. (2003) electrochemically synthesized thin films composed of ordered arrays of palladium nanowires using silica mesoporous channels. Mesoporous channels were deposited on a conductive glass substrate. In this method, nanowires with face-centered cubic crystal structure are continuously deposited from the conductive substrate upward until the mesoporous channels are filled. 

In addition to spherical particle nanocomposites, the preparation of nanotubes and nanowires composites with both magnetic and electrical properties is of great interest due to the enhancement of the conductivity. In general, the room temperature conductivity increases when the diameter decreases [79]. Conducting polymer nanotubes can be chemically or electrochemically synthesized by hard and soft template or template-free method in the presence of magnetic nanoparticles [8, 23, 27]. 

Li Q, Walter EC, van der Veer WE, Murray BJ, Newberg JT, Bohannan EW, Switzer JA, Hemminger JC, Penner RM (2005) Molybdenum disulfide nanowires and nanoribbons by electrochemical/chemical synthesis. J Phys Chem B 109 3169-3182 Tenne R, Homyonfer M, Feldman Y (1998) Nanoparticles of layered compounds with hollow cage structures (inorganic fuUerene-like structures). Chem Mater 10 3225-3238 Shibahara T (1993) Syntheses of sulphur-bridged molybdenum and tungsten coordination compounds. Coord Chem Rev 123 73-147... 

In contrast to nanowires synthesized by the pressure injection method, nanowires derived electrochemically are typically polycrystalline with no preferred crystal orientation. However, some exceptions occur. For example, polycrystalline CdS nanowires fabricated by ac electrodeposition in anodic alumina were shown to have a preferred wire growth orientation along the c axis (Routkevitch et al., 1996). Recently, Xu et al. (2000a, 2000b) prepared... 

Figure 19(a) shows the temperature dependence of resistance R(T) for bismuth nanowire arrays (dw = 7 - 200 nm) synthesized by vapor deposition and measured by Heremans et al. (2000). Hong et al. (1999) reported similar resistance measurements on bismuth wires of larger diameters (200 nm to 2, uni) prepared by electrochemical deposition (Fig. 19(b)). These two studies... 

Figure C.5. (top) Placement of the membrane on the copper electrode, fastened with electrical tape, (bottom) The electrochemical cell used to synthesize Ni nanowires.

Polypyrrole nanotubes synthesized at a constant potential using the pores of nanoporous polycarbonate (PC) particle track-etched membranes as a template [63,64] and polypyrrole nanowires synthesized at a constant potential of 0.9 V (vs. SCE) using nanochannels of proton-modified natural zeolite clinoptilolite [65] have been reported. Their electrochemical properties were improved compared to the conventional polypyrrole. 

---