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1.
Nanoscale ; 2(9): 1573-87, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20820688

RESUMO

Recently, one-dimensional (1D) ZnO nanomaterials (NMs) have been extensively studied because both their functional properties and highly controllable morphology make them important building blocks for understanding nanoscale phenomena and realizing nanoscale devices. Compared with high temperature (>450 degrees C) vapor phase methods, solution-based synthesis methods can be conducted at low temperatures (25-200 degrees C) allowing for compatibility with many organic substrate materials and offer additional advantages such as straightforward processing, low cost, and ease of scale up. Although there exist several review articles in the literature regarding the synthesis and applications of 1D ZnO NMs, those focusing on solution-based synthesis methods are lacking. Thus, this review focuses mainly on 1D ZnO NMs synthesized by solution-based processing. Firstly, 1D ZnO non-patterned, nanoparticle-seeded synthesis and its associated solution growth kinetics are discussed. Next, synthesis of vertically-aligned ZnO nanorod arrays with controlled pattern and density on various substrates is reviewed. Finally, important applications of 1D ZnO NMs are highlighted including sensors, field emission devices, photodetectors, optical switches, and solar cells.


Assuntos
Nanoestruturas/química , Soluções/química , Óxido de Zinco/química , Técnicas Biossensoriais , Cinética , Nanoestruturas/ultraestrutura , Energia Solar
2.
J Colloid Interface Sci ; 316(1): 183-8, 2007 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-17714726

RESUMO

Magnesium hydroxide sulfate hydrate (MHSH, 5Mg(OH)(2)MgSO(4)3H(2)O) nanobelts were synthesized under the conditions of ambient pressure and boiling temperature (approximately 101 degrees C). Several sparingly soluble carbonate salts were selected based on the hypothesis that the sparingly soluble carbonate salts in aqueous solution can provide OH(-) ion in a slow and continual manner, which is important to maintain a low supersaturation environment for one-dimensional MHSH nanobelt growth. The results indicated that the concentration of the reaction ions in the solution is one of the critical parameters for nanobelt growth. Scanning electron microscopy (SEM) showed that the nanobelts are about 50 nanometers in thickness, 200-500 nanometers in width and tens to hundreds of micrometers in length. The higher the solubility product constant of the sparingly soluble salt, the faster the reaction occurred. The effect of temperature on the reaction rate was investigated. The chemistry of the reaction was studied and the mechanism of nanobelt growth was proposed.

3.
J Phys Chem B ; 110(27): 13387-92, 2006 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-16821859

RESUMO

The nanobelt formation of magnesium hydroxide sulfate hydrate (MHSH) via a soft chemistry approach using carbonate salt and magnesium sulfate as reactants was successfully demonstrated. X-ray diffraction (XRD), energy dispersion X-ray spectra (EDS), selected area electron diffraction (SAED), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) analysis revealed that the MHSH nanobelts possessed a thin belt structure (approximately 50 nm in thickness) and a rectangular cross profile (approximately 200 nm in width). The MHSH nanobelts suffered decomposition under electron beam irradiation during TEM observation and formed MgO with the pristine nanobelt morphology preserved. The formation process of the MHSH nanobelts was studied by tracking the morphology of the MHSH nanobelts during the reaction. A possible chemical reaction mechanism is proposed.


Assuntos
Hidróxido de Magnésio/química , Sulfato de Magnésio/química , Nanoestruturas , Estrutura Molecular , Difração de Raios X
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