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First - Principles Study On Adsorption Of Adenine And Boron - Nitrogen By Carbon Nanotubes

Posted on:2016-12-27Degree:MasterType:Thesis
Country:ChinaCandidate:T ZhaoFull Text:PDF
GTID:2271330470968044Subject:Materials science
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The carbon nanotubes are as the new materials of the nano materials, great specific surface area, high strength and high tenacity and so on. All these outstanding properties have drawn the attetion of physicists, material scientists and chemists. An increasing number of experimental and theoretical research demonstrate that the CNNT-based nanotubes materials will be more and more important in nano-electronical appliance, and building materials.This artical investigates the doping and adsorption of CNT based on the current research. As for doping, this article optimizes geometric construction with LDA/6-21G and calculates energy band structure with HSE06/6-31G. Parametres like bond length, bond angle, lattice constant, pipe diametre, state density, forbidden bandwidth, doping density and formation energy are used in comparing BNNT with the same chirality.As can be seen from the result:The geometric structure and electronic structure of CNT with three different chiralities are all affected in doping. The max bond length and angle of CNT increase while the minimum numbers decrease, and the lattice constant increases as well. As the doping proportion grows, the forbidden bandwidth of chiral nanotubes and armchair nanotubes expand, but the change of forbidden bandwidth of zigzag CNT is small. The impurity of all these three CNTs peak around Fermi level in the figure of state density after doping. Systematic formation energy grows linearly as the doping proportion ascending. In terms of adsorption, the structures of CNTs with three different chiralities change little after adsorbing adenine molecules. When calculating the same model in five ways, the results fluctuate within a small range. When calculating the forbidden bandwidths, the result calculated by using B97XD is significantly different from the result calculated by using the rest four.CNT has a great potential for applications in new nano-materials. The special properties of CNT provide itself with broad applicatikn prospects. Our theoretical calculation is expected to contribute to following research on doping and adsorption of CNTs and to provide some reliable theoretical support, especially in the repects of DNA- doped and protein-doped CNTs which bring practical applications in biochemical area.
Keywords/Search Tags:Carbon nanotube, boron and nitride co-doping, adsorption, density of state, bandgap, formation energy
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