Transmission electron nanorods

Silver nitrate (AgN03) is a compound that fulfills the precedent requirements (Till = 212°C), and also it can be easily decomposed into pure silver by thermal treatment at 400 °C. As mentioned before, the basic characterisation technique for this studies is transmission electron microscopy (TEM) the atoms with rather high atomic number would facilitate the detection of the nanorods. 

Figure 6.3 Transmission electron micrographs of Ag and Au nanoparticles of different shapes used for doping of ureasils. (a) 30-nm Ag spheres, (b) 15-nm Au spheres, (c) Au nanorods with aspect ratio 2.13, and (d) Au nanorods with aspect ratio 2.99. [From Langmuir 2004, 20 (23), 10268.]...

In order to assemble gold nanorods (aspect ratio 2.4) by the click reaction, one batch of nanorods capped with 4-azidobutane-l-thiol, A, and another with hex-5-yn-l-thiol, B, were reacted in the acetonitrile-water mixture under standard conditions [12], The occurrence of the click reaction was established by infrared spectroscopy [13], The product of the reaction was investigated by electronic absorption spectroscopy and transmission electron microscopy. Fig. 1 compares the electronic absorption spectra of the gold nanorods before and after the click reaction between the A and B type nanorods. Isolated gold nanorods show transverse and longitudinal plasmon bands around 520 nm and 630 nm, respectively (see Fig. la). 

By carrying out the reaction of appropriate metal compounds with Na2S in the presence of a tripodal cholamide-based hydrogel, nanotubes and nanorods of CdS, ZnS and CuS have been obtained. The nanostructures have been characterized by transmission electron microscopy and spectroscopic techniques. Evidence is presented for the assembly of short nanorods to form one-dimensional chains. 2006 Elsevier B.V. All rights reserved. 

Fig. 28 From left to right-. Scanning transmission electron micrograph of crew-cut nanorods consisting of PS core and P4VP corona nanorods, coated with aluminum oxide and after removal of the polymer material [206]...

Magnetite nanorods have been prepared by the sonication of aqueous iron (II) acetate in the presence of yS-cyclodextrin [77]. The as-prepared magnetite nanorods are ferromagnetic and their magnetization at room temperature is about 78 emu g k The particle sizes measured from transmission electron micrographs are about 48/14 nm (L/W). A mechanism for the sonochemical formation of magnetite nanorods is discussed. 

Einally, europium oxide nanorods have been prepared by the sonication of an aqueous solution of europium nitrate in the presence of ammonia [85]. The particle sizes measured from transmission electron micrographs and HRSEM are about 50 X 500 nm (W x L). Sonication of an aqueous solution of europium nitrate in the presence of ammonia results in the precipitation of europium hydroxide The as-prepared material is europium hydroxide, as confirmed by TGA, DSC, XPS, and Mossbauer spectroscopy measurements, as well as by PXRD of the as-prepared sample assisted by microwave irradiation... 

Fig. 9.3. Transmission electron micrograph of gold nanorods, prepared by the seed-mediated growth method in water, in the presence of CTAB. Scale bar = 100 nm.

In the case of gold nanorods prepared in aqueous solution by the seed-mediated growth method, we have performed high-resolution transmission electron microscopy (HRTEM) and electron diffraction experiments as a function of growth time to crystallographically characterize the nanorods [45]. It is well-known that for the face-centered cubic (fee) structure of gold, the (111) face is the most stable, close-... 

Fig. 9.S. High-resolution transmission electron micrograph of a gold nanorod showing the double diffraction pattern, indicating twinning, taken from [45]. Scale bar = 5 nm. Reproduced by permission ofThe Royal Society of Chemist. ...

Fig. 9.7. Transmission electron micrographs showing concentration dependent ordering of gold nanorods, taken from [55]. (a) <1 wt% showing isolated nanorods some spherical particles are still present even after centrifugation, (b) 5-10 wt% showing smectic-like arrays, and...

Fig. 9.13. Transmission electron micrographs of gold nanorods, aspect ratio 18, before (a) and 24 h after (b) cyanide treatment. Reprinted with permission from [62], Copyright (2002) American Chemical Society.

X-ray diffraction technique is a non-destructive analytical technique that reveals information about crystallographic structure, chemical composition and physical properties of nanostructured materials. UV/Vis spectroscopy is routinely used in the quantitative determination of films of nanostructured metal oxides. The size, shape (nanocomb and nanorods etc,) and arrangement of the nanoparticles can be observed through transmission electron microscope (TEM) studies. Surface morphology of nanostructured metal oxides can be observed in atomic force microscopy (AFM) and scanning electron microscopy (SEM) studies. 

Another difficulty is that often only very small amounts of these anisotropic moieties can be synthesized at a time, limiting the study of the self-assembly properties to transmission electron microscopy analysis [135]. This makes it difficult to study in detail the phase diagram in concentration, usually a fairly sample consuming process. However, different approaches are currently being devised that give a taste of the huge potential that the self-assembly of these nanowires and nanorods can lead to. 

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