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X-ray diffractograms of two CoAl2O4 samples prepared by multicomponent (a) and single-source (b) precursor routes. Reprinted with permission from 244 , F. Meyer et al., J. Mater. Chem. 9, 1755 (1999). 1999, Royal Society of Chemistry. Similarly, nanocrystalline CuAl2O4 and NiAl2O4 could be obtained by processing CuAl2(OBu()8 and NiAl2(OBu')8 , respectively. Similarly, zinc aluminate (ZnAl2O4), a well-known wide bandgap semiconductor with a spinel structure, was prepared by the...

Interaction Between Hydrogen And Cnts

Current theoretical studies of simple physical adsorption on pure carbon nanotubes predict a maximum of 14 wt under low temperature and ideal conditions. The real adsorption process is likely to be more complicated, and the theoretical simulations have the potential for further refinement. In particular, as more quantitative and microscopically in-depth experimental results become available, the model parameters and assumptions will become more realistic. Only some of the experimental results...

Silicon Oxide Nitride and Carbide

Because of the covalent character of the chemical bonds, the nonoxide amorphous and nanocrystalline refractory ceramics exhibit a very high 3000 C melting point, low mobility of atoms, low plasticity, and high hardness at temperatures up to 2000 C. Therefore these materials can substitute for metals, alloys, and intermetallics in many high-temperature engineering, chemical, and electronic applications. The synthesis of silicon-containing ceramics oxide, carbide, nitride, etc. is an active...

Heterometal Chalcogenides

Ternary chalcopyrite materials such as copper indium dis-elenide CuInSe2 , copper indium disulfide CuInS2 , and copper gallium diselenide CuGaSe2 are potential solar cell materials, given that their direct bandgaps are nearly optimal for the absorption of the solar spectrum. High-quality thin films of solar-cell materials with high specific power W kg-1 are required to fabricate efficient devices. Nanocrystalline films are an attractive alternative to single-crystalline devices that are...

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Schematic illustrating micellar microemulsion nanoparticle synthesis. Reprinted with permission from 4 , G. G. Wallace and P. C. Innis, J. Nanosci. Nanotech. 2, 441 2002 . 2002, American Scientific Publishers. by extended polymer synthesis in the presence of self-assembled polystyrene cores that are selectively removed by toluene. Selvan et al. 96, 97 utilized a block copolymer micelle of in toluene exposed to tetrachloroauric acid which was selectively adsorbed by the micelle...

Microemulsion Technique

Microemulsions are transparent, isotropic dispersions of oil and water two immiscible liquids stabilized by the presence of carefully adjusted emulsifier s surfactant molecules that can be cationic, anionic, or neutral , which are located at the interfaces between oil and water domains 339 Scheme 10 . This systems are clear and thermodynamically stable, and they are prized for their stability and small particle size. The use of microemulsion technique in the synthesis of nano-particles is based...

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Single-source approach for preparing semiconductor nanocrystallites in TOPO. Reprinted with permission from 22 , T. Trindade et al., Chem. Mater. 13, 3843 2001 . 2001, American Chemical Society. Figure 26. Single-source approach for preparing semiconductor nanocrystallites in TOPO. Reprinted with permission from 22 , T. Trindade et al., Chem. Mater. 13, 3843 2001 . 2001, American Chemical Society. The importance of using small molecular clusters as syn-thons to extended solid-state...