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The Synthesis, Characterization, and Properties of CdS Nanostructures

Author: WangQingQing
Tutor: HanGaoRong
School: Zhejiang University
Course: Materials Science
Keywords: CdS Hydrothermal Solvothermal Nanostructures Quantum size effect
CLC: TB383.1
Type: Master's thesis
Year: 2006
Downloads: 650
Quote: 3
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Abstract


As a typical Ⅱ - Ⅵ group wide gap with direct semiconductor, room temperature band gap of 2.42eV, CdS has excellent photoelectric conversion characteristics and luminescent properties. With the reduction in the size and morphology of the changes, the band gap of the CdS nanostructures change dramatically, the result showed excellent optical and electrical properties different from the bulk, in light-emitting diodes, solar cells, optoelectronic display devices has potential applications. People use various methods of CdS nanoparticles morphology, particle size and particle size distribution of the control can be obtained with different optical and electrical properties of materials. This paper first introduces nanomaterials, classification, characteristics and nanomaterials synthesis method Ⅱ - Ⅵ group semiconductor compound CdS nanostructures synthesis, characterization and performance, and a detailed overview of the status quo. The organic surface modification, the auxiliary Hydrothermal Synthesis of a good dispersibility of the wurtzite CdS nanoparticles. Analysis of the structural characteristics of the wurtzite CdS selective adsorption of the surface-modifying agent is introduced in the solvent heating system, and select the different nature of the reaction mass and solvent solvothermal synthesis of CdS nanodots, nanorods / line and complex shaped crystalline appearance twigs. In this study, the main work and the main results obtained are as follows: 1 small size of CdS nano-particles dispersed poor, easy reunion, photoelectric performance degradation is not conducive to the actual application. This study introduction of the polyvinyl pyrrolidone (PVP) in hot water systems to be modified to obtain a good dispersibility and optical properties of the CdS nanoparticles on the surface of CdS nanoparticles. The PVP structure of the C = O can be formed with the CdS surface strong role adsorbed on the surface of the particles, and effectively limits the CdS nanoparticles grow. And due to the surface adsorption of PVP, not only inhibit the reunion of CdS nanoparticles, but also modification of the surface defects of the nano-particles, so that the synthesis of CdS nanodots having a good dispersibility and UV absorption properties. 2 CdCl 2 and of Na , 2 S · 9H 2 O reaction source, different proportions of ethylenediamine (en) and B The mixed solution of the diol as solvent solvothermal synthesis CdS nanodot the nanorods and 2-4 nanorods through point connected together multiple twigs structure. The binding force of the different polarity of ethylenediamine and glycol solvent and reactant, thereby affecting the effective concentration of the reactant in the system, the effective monomer concentration of ethylene glycol higher conducive cubic sphalerite phase CdS nucleation cubic phase and hexagonal phase CdS nanoparticles powder synthesis phase compound. The ethylenediamine and the reaction was the effective concentration of the strong complexation, so that the reaction was reduced, suppressed cubic phase CdS generation, can be obtained pure wurtzite phase CdS powder. And orientation growth characteristics due to the intrinsic structure of the wurtzite CdS wurtzite CDS grown as the nano-rods. Cubic phase CdS nuclei of the {111} crystal faces family of four products in the same plane with the (001) crystal face of hexagonal phase CdS can be grown in these four surfaces 2-4 wurtzite structure nanorods formed connected together multiple twigs structure. Reaction materials. CdCl 2 and thiourea, ethylenediamine as the solvent, the introduction of the appropriate amount of PVP as surface modifiers to limit the growth of nanowires side Solvothermal synthesis with good crystallinity of CdS nanorods, a diameter of about 20 nm to 2 microns long. The PVP surface adsorption, not only enhanced the CdS orientation growth of real

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