Three-Dimensional Nanostructures

There are many other experiments in which surface atoms have been purposely moved, removed or chemically modified with a scanning probe tip. For example, atoms on a surface have been induced to move via interaction with the large electric field associated with an STM tip [78]. A scaiming force microscope has been used to create three-dimensional nanostructures by pushing adsorbed particles with the tip [79]. In addition, the electrons that are tunnelling from an STM tip to the sample can be used as sources of electrons for stimulated desorption [80]. The tuimelling electrons have also been used to promote dissociation of adsorbed O2 molecules on metal or semiconductor surfaces [81, 82]. 

Yuan, J., Li, W., Gomez, S. and Suib, S.L. (2005) Shape-controlled synthesis of manganese oxide octahedral molecular sieve three-dimensional nanostructures. Journal of the American Chemical Society, 127, 14184-14185. 

For further details an animated description of electron tomographic work on three-dimensional nanostructure analysis based on Rutherford scattering (/17-119) see http // www.hrem.msm.cam.uk/ mw259/Work/Tomo.html. 

In the first case, the details of network build-up and modification of network structure described above are not very important. The main aim of crosslinking is to keep the dendritic structures together permanently. Formation of three-dimensional nanostructures by metal-mediated self-assemblage can serve as an example Exo-tridentate tripyridyl compounds self-assemble upon treatment with (en)Pd(N03)2 [66]. 

We have discovered a novel protein immobilization method, i.e., a Three-Dimensional Nanostructured Protein Hydrogel (3-D NPH), which is composed of protein-reactive polymer hybrid nanoparticles to detect protein-protein interactions. The 3-D NPH can be easily prepared by spotting a protein/reactive polymer mixture on a substrate. The resulting 3-D NPH is characterized by large amounts of immobilized proteins and a novel porous structure. 

In this chapter, we intend to revise the most recent contributions to the aforementioned aspects of Pc research. We will describe how the versatile chemistry of Pcs makes possible the preparation of monofunctionalized macrocycles, mainly aimed at preparing multicomponent systems through reaction with other electroactive moieties. The controlled organization of Pcs in solution and the incorporation of these chromophores into macromolecular structures, as well as the preparation of mono-, bi-, and three-dimensional nanostructures, will be the object of study. Finally, some examples of Pc-based devices (solar cells, sensors, transistors, etc.) will also be given as an example of the real applicability of these molecules. 

Stretching vibrations and indicated that the R6G were adsorbed on the surface of Ag-MWCNTs-Nafion. The characteristic Raman peaks in Fig. 6.3 were in agreement with other works [47, 72-74]. The SERS intensity of R6G obtained at the surface of Ag-MWCNTs-Nafion is higher than those at the surfaces of Ag and Ag-CB-Nafion. The results show that the three-dimensional nanostructure of... 

At the top of systems proposed for processors of quantum computers, there are systems in which electronic and nuclear spins of various defects and impurities in diamond are used as stationary qubits [1,2]. Single NV-centers having electronic spin S=1 in the ground electronic state are the most promising [3]. To improve optical read-out of such spin-states, various three-dimensional nanostructures in diamond such as micro resonators, waveguides, photon-crystal structures, etc. [1,4,5] are being developed. Besides, the methods of NV-center... 

Synthesis of one dimensional, two dimensional and three dimensional nanostructured metal oxides have attracted a great deal of interest for the past many years. Because of their size dependent catalytic and optoelectronic properties, they can be broadly tuned through size variation. Recently, extensive efforts have been made to synthesize one dimensional metal oxides nanostructures such as nanowires, nanobelts, nanotubes, nanorods, nanorings etc [Fig.2], Various methods have been used in literature for development of nanostructured metal oxides of varying shape and sizes are as follows. 

Cao, M., He, X., Chen,). and Hu, C. (2007) Self assembled nickel hydroxide three dimensional nanostructures A nanomaterial for alkaline rechargeable batteries. Crystal Growth Design, 7, 170-174. 

Matsui, S., Kaito, T, Fujita, J. et al. 2000. Three-dimensional nanostructure fabrication by focused-ion-beam chemical vapor deposition. Journal of Vacuum Science and Technology B 18 3181-3184. 

Three-dimensionally nanostructured transparent conducting ZnO could serve as electrode for several applications such as dye-sensitized solar cells. Thus, the template-assisted nanopatterning of ZnO via electrodeposition was attempted, following the... 

Chapter 12 focuses on recent advancements in EMM for micro and nanofabrication. It contains various emerging variants of EMM. Various interesting factors of surface structuring of aluminum, stainless steel, and titanium, etc., by EMM have been presented considering not only simple flat surfaces but also complex curved surfaces. EMM can also be successfully utilized for fabrication of three-dimensional nanostructures which has also been reported. 

Fujita J, Ishida M, Sakamoto T, Ochiai Y, Kaito T, Matsui S. Observation and characteristics of mechanical vibration in three-dimensional nanostructures and pillars grown by focused ion beam chemical vapor deposition. J Vac Sci Technol B Microelectron Nanometer Struct 2001 19 2834-7. 

When one of the dimensions of the material is in nanoscale, the material is known as a nanomaterial. Depending on the procedure for synthesis, the shape and size of the polymeric nanomaterial is altered. Hence the optimization process in the synthesis of any polymeric nanomaterial is critically important for its reproducibility. Various morphologies possessed by the electronically conducting polymeric nanomaterials are nanoparticles, thin films, nanotubes, nanorods, etc. Some special kinds of morphologies such as flower-like, dendritic, fibril-like, etc., are also foimd to exist. Some of the three-dimensional architectures contain the combination of various morphologies of the same polymeric material. The various structures are particularly important to their application. For example, for electrode purposes, the materials should have large surface area and hence three-dimensional nanostructures are preferred. 

In addition to one-dimensional and two-dimensional silicon anodes, several forms of three-dimensional nanostructured silicon have been explored. For example, silicon nanotubes (Fig. 15.9) were investigated by Cho et al. [21] as an anode material for lithium-ion batteries. Both interior and exterior surfaces of the nanotubes are accessible to the electrolyte and lithium ions. Through carbon coating, a stable solid electrolyte interface (SEI) was generated on the inner and outer surfaces of the silicon nanotubes. These silicon/carbon assemblies showed a reversible capacity as high as 3,247 mAh/g (based on the weight of silicon) and good capacity retention. 

To further improve the mechanical and electrical stability of silicon-based anodes, a hierarchical bottom-up approach (Fig. 15.12) was successfully utilized to develop a three-dimensional nanostructured silicon/carbon porous composite [89]. The existence of pores in the composite granules provides sufficient space to accommodate silicon expansion during lithium insertion. CVD deposition of silicon clusters (Fig. 15.12b) avoids formation of SiO thus reducing the first cycle, irreversible capacity. A high specific capacity of 1,950 mAh/g (C/20 rate) based on the total weight of the silicon/carbon composite was reported. In addition, the composite anodes had negligible capacity fade after 100 cycles at 1C rate and excellent rate capability (870 mAh/g at 8C rate). 

Replication techniques are available for transforming complex silica shapes into the corresponding shapes of various polymers. Ihe process can also be extended in the opposite direction, by converting the silica into silicon. Specifically, a low-temperature reduction process has been developed to convert three-dimensional nanostructured silica micro-assemblies into microporous nanocrystalline silicon replicas. Such materials could be useful in a variety of applications, including sensors and biomedical devices. 

Self-orienting and self-limiting specifics of the etching process of porous Si, combined with straightforward geometrical approaches, opens a unique way of three-dimensional nanostructuring... 

Anderson ML, Stroud RM, Rolison DR (2002) Enhancing the activity of fuel-ceU reactions by designing three-dimensional nanostructured architectures catalyst-modified carbon-siUca composite aerogels. Nano Lett 2 235-240... 

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