Oxide Nanocrystals

Tan, Y.W., Zhuang, Z.B., Peng, Q. and Li, Y.D. (2008) Room-temperature soft magnetic iron oxide nanocrystals ... 

Pinna, N., Garnweitner, G., Antonietti, M. and Niederberger, M. (2005) A general nonaqueous route to binary metal oxide nanocrystals involving a C-C bond cleavage. Journal of the American Chemical Society, 127 (15), 5608-5612. 

Yu, W.W., Falkner, J.C., Yavuz, C.T. and Colvin, V.L. (2004) Synthesis of monodisperse iron oxide nanocrystals by thermal decomposition of iron carboxylate salts. Chemical Communications, (20), 2306-2307. 

Khagram, P., Tomson, F., Brydson, R.M.D. and Crook, R. (2010) Synthesis ofhigh quality monodisperse nickel oxide nanocrystals. Journal of Physics Conference Series, 245, 012063. 

Ba, J. H. Polleux, J. Antonietti, M. Niederberger, M. 2005. Non-aqueous synthesis of tin oxide nanocrystals and their assembly into ordered porous mesostruc-tures. Adv. Mater. 17 2509-2512. 

Decker, S.P. Characterization and reactivity of calcium oxide and iron oxide coated — calcium oxide nanocrystals. Ph.D. thesis. Kansas State University, Manhattan, KS, 1998. 

Liang, Y., et al., Oxygen reduction electrocatalyst based on strongly coupled cobalt oxide nanocrystals and carbon nanotubes. Journal of the American Chemical Society, 2012.134(38) p. 15849-15857. 

Hasse U, Scholz F (2001) In situ atomic force microscopy of the reduction of lead oxide nanocrystals immobihsed on an electrode surface. Electrochem Commun 3 429-434. 

Metal oxide nanocrystals arc mainly prepared by the solvothermal decomposition of organometallic precursors. Solvothermal conditions afford high autogenous pressures inside the scaled autoclave that enable low-boiling solvents to be heated to temperatures well above their boiling points. Thus, reactions can be carried out at elevated temperatures and the products obtained are generally crystalli ne compared to those from other solution-based reactions. 

In contrast to the dry methods, there are other conventional methods related to post heat treatment from precipitates from the aqueous solutions. The ambient aqueous routes and the hydrothermal methods at elevated temperature usually lead to rare earth precipitates like hydroxides, carbonates, instead of oxides. In fact, the hydrothermal treatment of rare earth oxide powders results in a hydration process to form hydroxides. Subsequently, the precursor could be used to produce rare earth oxide nanocrystals with post annealing at varied temperatures and in appropriate atmosphere. 

Colloidal synthesis The aqueous synthesis routes could not yield rare earth oxides directly without postheat treatment, while the dry routes usually lead to products with relatively wide size distribution and the nanocrystals could not be dispersed as colloidal solutions. Therefore, it is highly desirable to synthesize R2O3 nanocrystals in suitable nonaqueous solutions. However, the decomposition of rare earth precursor and crystallization of rare earth oxide nanocrystals would require an elevated temperature. Therefore, the solvents are usually with a high boiling point, which are called "high-boiling solvents."... 

Bazzi et al. (2003, 2004) reported (Figure 19) the colloidal precipitation from polyalcohol solution to obtain stable colloidal suspensions of luminescent doped rare earth oxide nanocrystals with an average grain... 

Luminescence Photoluminescence of rare earth oxide nanocrystals is one of their most significant properties of interest for applications. The photoluminescence features of rare earth doped nanomaterials have been reviewed by Liu and Chen in an earlier chapter (Liu and Chen, 2007b). Therefore, we only review some related aspects, such as the major variations in the luminescence features of nanophased rare earth oxides, the application of rare earth doped nanocrystals as multicolor phosphors and as bioimaging probes. 

Hu and coworkers developed a composite hydroxide method (CHM) to symthesize highly crystallized rare earth hydroxide and oxide nanocrystals (Hu et al., 2007). The eutectic mixture of alkaline hydroxides (NaOH KOH = 51.5 48.5, m.p. 165 °C) is used as solvent and the real synthetic process is done at approximately 200 °C in a sealed vessel. The highly crystallized La(OH)3 nanobelts are obtained through this method... 

Kennedy, M.K., Kruis, F.E., Fissan, H., Mehta, B.R., Stappert, S., and Dumpich, G., Tailored nanoparticle films from monosized tin oxide nanocrystals particle synthesis, film formation, and size-dependent gas-sensing properties, J. Appl. Phys., 93, 551, 2003. 

Yin JS, Wang ZL (1997) Ordered self-assembling of tetrahedral oxide nanocrystals. Phys Rev Letters 79 2570-2573... 

The very first report of two-dimensional arrays was of Fe304 nanocrystals [128]. Bentzon et al. observed that the ferrofluid obtained by thermolysis of iron penta-carbonyl upon drying (over a period of several weeks) yielded well ordered two-dimensional arrays of Fe304 nanocrystals. Since then, easier methods have been devised to obtain arrays of Fc304 nanocrystals [129]. Two-dimensional arrays of amine-capped metal oxide nanocrystals such as C03O4 have been obtained by start-... 

Gonzales M, Krishnan MK (2005) Synthesis of magnetoliposomes with monodisperse iron oxide nanocrystal cores for hyperthermia. J Magn Magn Mater 293 265-270... 

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