Dissertation > Excellent graduate degree dissertation topics show

Preparation and Application of Water Soluble CdSe Quantum Dots and CdSe Nanoparticles

Author: HuZhenLong
Tutor: HuangZhengXi
School: Central South University for Nationalities
Course: Physical and chemical
Keywords: CdSe quantum dots Sodium carboxymethyl cellulose Photoluminescence Photooxidation Photodegradation
CLC: O614.242
Type: Master's thesis
Year: 2013
Downloads: 24
Quote: 0
Read: Download Dissertation

Abstract


Due to its unique fluorescence properties and significant size effect, CdSenano-materials have been extensively studied in physics, chemistry and biology fields.CdSe quantum dots （QDs） has been appreciated by lots of researchers for its excellentqualities. It is always a hot spot for researchers that how to get CdSe QDs with excellentfluorescence through the physical and chemical methods. CdSe possess1.7eV of bandgap and very excellent spectral response range. It is considered as an idealphotosensitive material and has potential applications in environmental remediation andenergy conversion, the most critical issue is how to improve the light utilizationefficiency. This thesis study the fluorescence properties and photocatalytic degradationactivity of CdSe QDs. Surfactant and the treatment of light oxidation were used toimprove the fluorescence properties of the CdSe QDs. In addition, CdSenanomicrospheres and CdSe/sulfhydryl cellulose （SC） nanocomposite material wereprepared and the ability to photocatalytic degradation dyes were studied. The mainimportant work of this paper as follows:1. CdSe quantum dots was prepared in aqueous phase modified by non-toxic,environment friendly and good biocompatibility sodium carboxymethyl cellulose（CMC）. The CdSe QDs is nearly monodispersed and the average particle size only2.1nm. Particle size of QDs could be controlled by adding different amount of sodiumselenosulphate, thus to adjust photoluminescence （PL） from480nm to560nm. AndQDs have narrow and symmetrical PL spectra, and the PL quantum yield increase to32%. The interaction with the Schiff base show that Schiff base can effectively enhancethe PL of QDs in a certain range, but excess Schiff base will quench the PL.2. Thioglycollic acid （TGA）-CdSe QDs were prepared in aqueous phase by additionof different surfactants. Several nanometer-sized, well-dispersed, fluorescence-enhancedCdSe QDs could be obtained by addition of long-chain anionic and non-ionicsurfactants. However, the PL of CdSe QDs is quenched and the particle aggregation bythe addition of cationic surfactants.3. The PL intensity of both CMC-CdSe QDs and TGA-CdSe QDs could be enhancedupon illumination. The X-ray photoelectron spectrum （XPS） and PL spectra confirm SeO2formed by irradiation could passivate the CMC-CdSe QDs surface and give rise toa great increment in PL intensity. And CdS shell formed in the system of TGA-CdSeQDs could oxide water and produce hydroxyl radicals. It made TGA-CdSe QDs didn’thave selectivity for most of dyes and could achieve well results of degradation in a shorttime.4. CdSe microspheres and CdSe/SC nano-composite as photocatalysts wereprepared in aqueous phase. CdSe nano-microspheres could partially degrade RhodamineB （RhB） and light irradiation can increase the catalytic activity and enhance thephotocatalysis ability of the catalyst. The effect of light treatment in the photocatalyticdegradation of RhB is two sides: On one hand, it can enhance the degree ofcrystallization without change the form of crystal that increase the adsorption of RhB,and oxidize Se（-II） to Se（IV）. On the other hand, it can extend the spectral response.CdSe nanoparticles was loaded on SC successfully by coordinated bond，rather than thesimple doping or mixing. The nano-composite is excellent photocatalyst.

Related Dissertations

  1. Study on the Photodegradation of Ciprofloxacin in Water,X592
  2. Synthesis, In-situ Mechanical and Electrical Properties of One-dimentional Carbide Nano-materials Generated from Plant Fibers,TB383.1
  3. Synthesis, Characterization and Properties of One-dimensional Silicon Carbide Nanomaterials,TB383.1
  4. Fabrication and Characterization of Nano-ZnO by PLA in Liquid Solution,TB383.1
  5. Study on the Photoluminescence Properties of the Rare Earth Doped Oxide Phosphors Prepared by Hydrothermal Method,TQ422
  6. Synthesis and Study of ZnO Nanostructures in Ionic Liquid by Electrochemical Deposition,TB383.1
  7. Removal Characteristics and Mechnism of Dichloromethane Photodegradation by Irradiation of Vacuum Ultraviolet,X511
  8. Electro-assisted Self-assembly and Properties of Silica Films,TB383.2
  9. The Preparation and Characterization of Functional Composite Humidity-Controlling Materials,TB34
  10. Luminescence and Vibrating Properties of Zn-based GroupⅡ-Ⅵ Nanostructures,TB383.1
  11. Structural Integration Design for Efficient Photoluminescence in Butterfly Scales and Its Biomimetic Materials,TB34
  12. Study on Hydrophobic Modification of Sodium Carboxymethyl Cellulose and Ph-Sensitive Hydrogel,O631.3
  13. Investigation on the Wide Spectrum Nano-Folding of Active Region LED Technology,TN304
  14. The Fabrication of All-optical Switches Based on Active Photonic Band Gap Bragg-spaced Multiple Quantum Wells,TN256
  15. Sustained-release drug delivery systems containing avermectin Preparation and Properties,TQ460.1
  16. Terphenyl liquid crystal containing chiral polyacetylene Synthesis and Properties,O631.3
  17. Synthesis of Nanoparticulate ZnO, Cu-Doped ZnO and Their Properties,TB383.1
  18. Production of Needled Nano-ZnO and Research of Its Application,TB383.1
  19. Syntheses, Crystal Structures and Properties of Transition Metal Coordination Polymers Based on Benxotriazole-5-carboxylate Ligand,O621.13
  20. Study the Effect on Proliferation and Cell Cycle of Human Periodontal Ligament Cells by Nano-hydroxyapatite Suspension,R783
  21. Carbothermal reduction and the preparation of silicon carbide nanowires its performance,TB383.1

CLC: > Mathematical sciences and chemical > Chemistry > Inorganic Chemistry > Metal elements and their compounds > Section II group metal element and its compounds > The zinc Vice family (Ⅱ B group metal elements ) > Cd Cd
© 2012 www.DissertationTopic.Net  Mobile