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The Preparation Of Metal Organic Complexes M-tcnq Micro-nano Structure And Hydrogen Absorption Properties

Posted on:2006-10-30Degree:DoctorType:Dissertation
Country:ChinaCandidate:G Y CaoFull Text:PDF
GTID:1111360155460604Subject:Physical Electronics
Abstract/Summary:PDF Full Text Request
One-dimensional (1-D) micro/nano materials have recently become the research focus of nanotechnology owing to their unique chemical, physical and mechanical properties. Functional metal-organic complexes of M-TCNQ, with highly intrinsic anisotropy in crystal structure, are of considerable interest due to their unique optical, electrical and magnetic properties. 1-D micro/nanostructures of these complexes and their physical properties are triggering more and more interest all over the world.In this dissertation, the synthesis and hydrogen absorption property of M-TCNQ with 1-D micro/nanostructures were studied.Three methods, i.e. novel vapor transport reaction, solution reaction and developed vapor-induced reaction, were used to prepare the 1 -D micro/nanostructures of M-TCNQ (M= Ag, Cu). Different morphologies, such as nanowires, nanorods and microtubes were obtained and characterized by SEM, XRD and Raman.Growth conditions and mechanism of Ag-TCNQ micro/nanostructures prepared by solution reaction were investigated. It was found that the thicknesses of Ag films, TCNQ concentration, reaction temperature and time influence significantly and interact with each other on the final morphologies of the as-grown samples. The thickness of Ag films with 5-10 nm and non- saturated TCNQ solution should be used when sparse and individual micro/nanostructures are wanted. Moreover, the formation process of the Ag-TCNQ micro/nanostructures via solution reaction was studied by a specially designed experiment. It was found that the formation of these micro/nanostructures proceeds through the nucleation and directional growth steps, and is governed by the nucleation-diffusion-controlled growth mechanism. Additionally, the reversible photochromism of the individual Ag-TCNQ micro/nanostructures were found.The dendrites and fractals were observed when the solution was badly supersaturated. This was attributed to the poor solubility of Ag-TCNQ in acetonitrile. The morphology and formation mechanism were investigated experimentally and theoretically. The final morphologies result from the different places of splitting of the columned seeds formed in the initial nucleation. This splitting is caused by the competition between the diffusion of the solute and the anisotropy of growth. The cluster-like microstructures is considered to be the "default morphology". The calculated fractal dimensions of these dendrites show that the growth process shares...
Keywords/Search Tags:Metal-organic complex M-TCNQ, nanowires, microtubes, vapor-induced reaction, growth mechanism, photochromism, dendrites and fractals, thermal stability, hydrogen absorption
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