Author: Pavan K. Dasari
Publisher:
ISBN:
Category : Nanostructures
Languages : en
Pages : 162
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Book Description
Electrochromic tungsten trioxide (WO3) solutions were synthesized utilizing a sol-gel processing technique. These solutions by their very nature are unstable and readily precipitate without stabilization. Both polymer based stabilization using polyethylene oxide (PEO) and electrostatic stabilization by pH modification methods were utilized to stabilize and isolate WO3 colloids. Tungsten colloidal nanoparticles in the size range of 10 to 50 nm were observed. The primary goal of this work was to explore and control the sizes of nano particles of WO3 under various conditions. Data obtained from atomic force microscopy (AFM), scanning electron microscopy (SEM), dynamic light scattering measurements (DLS) gave convincing results about the different growth rates of tungsten colloids. We also obtained information regarding the shapes of WO3 particles. Long needle-like dendrites are seen at low concentrations of PEO and flower like crystallized structures are obtained at higher concentrations. All these results provided substantial evidence about different growth rates of WO3 colloids.
Author: Rong Hu
Publisher:
ISBN: 9781374678644
Category :
Languages : en
Pages :
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Author: Rong Hu (Ph. D.)
Publisher:
ISBN:
Category : Nanostructures
Languages : en
Pages : 166
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Author: Daniela Nunes
Publisher: Elsevier
ISBN: 012811505X
Category : Technology & Engineering
Languages : en
Pages : 331
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Book Description
Metal Oxide Nanostructures: Synthesis, Properties and Applications covers the theoretical and experimental aspects related to design, synthesis, fabrication, processing, structural, morphological, optical and electronic properties on the topic. In addition, it reviews surface functionalization and hybrid materials, focusing on the advantages of these oxide nanostructures. The book concludes with the current and future prospective applications of these materials. Users will find a complete overview of all the important topics related to oxide nanostructures, from the physics of the materials, to its application. - Delves into hybrid structured metal oxides and their promising use in the next generation of electronic devices - Includes fundamental chapters on synthesis design and the properties of metal oxide nanostructures - Provides an in-depth overview of novel applications, including chromogenics, electronics and energy
Author:
Publisher:
ISBN: 9789175192659
Category :
Languages : en
Pages : 71
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Author: 洪昆權
Publisher:
ISBN: 9781374667396
Category :
Languages : en
Pages :
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This dissertation, "Synthesis of One-dimensional Tungsten Oxide Nanostructures" by 洪昆權, Kunquan, Hong, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled SYNTHESIS OF ONE-DIMENSIONAL TUNGSTEN OXIDE NANOSTRUCTURES Submitted by Hong Kunquan for the degree of Doctor of Philosophy at The University of Hong Kong in January 2008 Tungsten oxide has been used for various optical devices, sensors and so forth for its outstanding electrochromic, optochromic, gaschromic and electronic properties. One-dimensional (1D) tungsten oxide nanostructures are expected to improve the performance of those devices as well as to open up new applications. o Generally, high temperature (1200-2000 C) and special equipments are required in the synthesis of these tungsten oxide nanostructures, which can be obstacles for a wider application. In this thesis, some new methods have been developed to synthesize 1D tungsten oxide nanostructures. The relevant growth mechanisms were also investigated. Firstly, a simple method was devised to grow tungsten oxide nanostructures by thermal evaporation at low temperature and yet without using catalyst. By o heating tungsten powder at 650 C, and tungsten plate or tungsten powder covered o silicon substrates at 400 C, tungsten oxide (W O ) nanowires with diameter of 18 49 10-50 nm were obtained with high quantity. It was further shown that the presence of a pre-oxide layer on tungsten substrate is essential for high yield W O 18 49 nanowire growth. Under optimal conditions, the diameter of the nanowires can be decreased down to 4-7 nm. Second, when potassium iodide (KI) was introduced in the synthesis, various types of nanostructures or micro-structures, such as tungsten oxide and potassium tungstates (K W O ) micro-walls were obtained, depending 2 3 10 on the temperature of substrate, the gas flow and the pressure in the reactor. It was o found that tungsten oxide nanowires can be synthesized at 400 C in the presence of KI, and the addition of source materials will enhance the growth. Finally, by thermally evaporating tungsten trioxide powder source, tungsten oxide W O nanowires were also synthesized with high yield and on a large 18 49 scale. Depending on the temperature of the source (in the range of 900-1000 C), the diameter of the tungsten oxide nanowires varies from 10 nm to 100 nm, following an exponential relation. Nanowires with controllable diameter are therefore obtainable by this method. Under other conditions, nanowires, nanoplates, nanocrystals and comb-like nanostructures were obtained on silicon substrate. The growth mechanisms of these nanostructures, especially the dependence of nanowire size on source temperature, were further investigated. It is found that the diameter of nanowires increases with growth time but a maximum diameter seems to exist as determined by the source temperature. A theoretical model was used to analyze the growth mechanism for the diameter control where zero-dimensional (0D) and two-dimensional (2D) nucleation contribute to the growth of length and the diameter of the nanowire respectively. DOI: 10.5353/th_b3955855 Subjects: Tungsten oxides - Synthesis Nanostructures
Author:
Publisher: Elsevier
ISBN: 0128133589
Category : Technology & Engineering
Languages : en
Pages : 612
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Book Description
Colloidal Metal Oxide Nanoparticles: Synthesis, Characterization and Applications is a one-stop reference for anyone with an interest in the fundamentals, synthesis and applications of this interesting materials system. The book presents a simple, effective and detailed discussion on colloidal metal oxide nanoparticles. It begins with a general introduction of colloidal metal oxide nanoparticles, then delves into the most relevant synthesis pathways, stabilization procedures, and synthesis and characterization techniques. Final sections discuss promising applications, including bioimaging, biosensing, diagnostic, and energy applications—i.e., solar cells, supercapacitors and environment applications—i.e., the treatment of contaminated soil, water purification and waste remediation. - Provides the most comprehensive resource on the topic, from fundamentals, to synthesis and characterization techniques - Presents key applications, including biomedical, energy, electronic and environmental - Discusses the most relevant techniques for synthesis, patterning and characterization
Author: Razium Ali Soomro
Publisher:
ISBN: 9783668490208
Category :
Languages : en
Pages :
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Author: José A. Rodriguez
Publisher: John Wiley & Sons
ISBN: 0470108967
Category : Technology & Engineering
Languages : en
Pages : 640
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Book Description
Current oxide nanomaterials knowledge to draw from and build on Synthesis, Properties, and Applications of Oxide Nanomaterials summarizes the existing knowledge in oxide-based materials research. It gives researchers one comprehensive resource that consolidates general theoretical knowledge alongside practical applications. Organized by topic for easy access, this reference: * Covers the fundamental science, synthesis, characterization, physicochemical properties, and applications of oxide nanomaterials * Explains the fundamental aspects (quantum-mechanical and thermodynamic) that determine the behavior and growth mode of nanostructured oxides * Examines synthetic procedures using top-down and bottom-up fabrication technologies involving liquid-solid or gas-solid transformations * Discusses the sophisticated experimental techniques and state-of-the-art theory used to characterize the structural and electronic properties of nanostructured oxides * Describes applications such as sorbents, sensors, ceramic materials, electrochemical and photochemical devices, and catalysts for reducing environmental pollution, transforming hydrocarbons, and producing hydrogen With its combination of theory and real-world applications plus extensive bibliographic references, Synthesis, Properties, and Applications of Oxide Nanomaterials consolidates a wealth of current, complex information in one volume for practicing chemists, physicists, and materials scientists, and for engineers and researchers in government, industry, and academia. It's also an outstanding reference for graduate students in chemistry, chemical engineering, physics, and materials science.
Author: Alexander Charles Santulli
Publisher:
ISBN:
Category : Chemistry
Languages : en
Pages :
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