Dissertation > Excellent graduate degree dissertation topics show

Preparation and Photoluminescent Properties of Ln-Doped Layered Potassium Lanthanoniobate Phosphors

Author: FuLiMei
Tutor: LinBiZhou
School: Huaqiao University
Course: Inorganic Chemistry
Keywords: KLaNb2O7 Dy3+/Er3+ Nanosheets Multiple films Photoluminescence
CLC: O611.4
Type: Master's thesis
Year: 2012
Downloads: 25
Quote: 0
Read: Download Dissertation

Abstract


Luminescence materials has wide application prospects in optical display,lighting project, photoelectric detection, biological marker, medical diagnosis andtreatment area. The development of new luminescence materials with energy efficientis one of the current research hotspot. The layered perovskite KLaNb2O7’s structure isstability, and has good mechanical properties and physical and chemical properties.This paper chooses KLaNb2O7as the object of our study. The intralayer dopedcompounds was prepared and then exfoliated to nanosheets. After restacking, thenanosheets multiple films and interlayer-intercalated compounds were prepared. Thestructures, morphologies, thermal stability and luminescence properties of theluminescent materials were characterizated by means of XRD, fluorescence spectra,UV-Vis, IR, XPS, SEM, TEM and so on.Rare-earth ions doped KLa0.95-xLnxNb2O7(Ln=Dy3+、Er3+)were prepared by asolid state reaction. Within certain range of concentrations, the doped potassiumlanthanum niobate maintains the same layered structure，its absorption wavelenghhave blue-shifted and the optimal doping of rare earth ions is5%. Thephotoluminescence emission of KLa0.95-xLnxNb2O7via host excitation is negligiblylow in intensity, whereas the emission via direct Ln3+excitation has apparently beenobserved. On the contrary, the emission via host excitation becomes far morepredominant than that via direct Ln3+excitation for the La0.90Ln0.05Nb2O7nanosheet.(PEI/La0.90Dy0.05Nb2O7)nmultiple films was obtained by layer-by-layer method.And then treated it by heat or UV light. The AFM data suggested that the averageheight of a single La0.90Dy0.05Nb2O7nanosheet was1.13nm. Both the as-preparedmultiple films and its post-treated products displayed stonger hostexcitation-Mediated photoluminescence origined from O2-→Dy3+and O–Nb→Dy3+energy transfer. While there was not observed emission from direct Dy3+excitation.Utilizing the exfoliation and restacking properties of lanthanum niobate, Dy3+、Er3+-intercalated lanthanum niobate layered nanocomposites assembled from niobatelayer and Dy3+, Er3+have been successfully prepared. The gallery height ofnanocomposite increased about0.37and0.33nm. Thermal analyses suggested that the resulting meterial shows good thermal stability. The analysis results by UV-Vis,XPS suggested there is some strong interaction between hosts and guests which madethe intercalated composites’s absorption wavelengh red-shifted and the biding energyof Nb3d,La3d,O1s increased. The fluorescence results suggested that the emissionvia direct Ln3+excitation was far more predominant than that via host excitation forboth the as-prepared intercalated compounds and its post-treated products. After heattreated the direct Ln3+excitation intensity was increased,while the host excitationweakened.

Related Dissertations

  1. Eu- doped α-SiAlON phosphor First-principles study,TB34
  2. Prepration of Manganses Dioxide and Investigation on the Performance of Supercapacitor,TM53
  3. Fabrication and Characterization of Nano-ZnO by PLA in Liquid Solution,TB383.1
  4. CdSe/ZnS Quantum Dot Doped Fibers and the Gain Performance,TN253
  5. Study on the Photoluminescence Properties of the Rare Earth Doped Oxide Phosphors Prepared by Hydrothermal Method,TQ422
  6. Luminescence and Vibrating Properties of Zn-based GroupⅡ-Ⅵ Nanostructures,TB383.1
  7. The Fabrication of All-optical Switches Based on Active Photonic Band Gap Bragg-spaced Multiple Quantum Wells,TN256
  8. ZnO nanocrystalline structure of the film luminescence and doping,O484
  9. Silicon nanocrystal photoluminescence and electroluminescence modulation studies,TB383.1
  10. Synthesis of Nanoparticulate ZnO, Cu-Doped ZnO and Their Properties,TB383.1
  11. The Research of Low-carbon Hygrogenate Amorphous Silicon Carbide,TB34
  12. Synthesis and Properties of the Molydbate Nanocrystals,TB383.1
  13. Luminescence Properties of Thenardite Activated with Eu and Tb,O482.31
  14. Hydrothermal Preparation and characterization of nano - ZnO and yttrium aluminum garnet,TB383.1
  15. Controllable Growth and Properties of ZnO Nanorod Arrays,TB383.1
  16. Study on the Synthesis and Optical Properties of New Inorganic Luminescent Materials Co-doped with Rare Earth Ions,O611.4
  17. Study on Spectral Characteristics of CdSe/ZnS-Quantum-Dot Doped Fibers with High Doping Concentrations,TN253
  18. Nematic liquid crystal polymer sheet of light-driven bending behavior analysis,O753.2
  19. Fabrication and Photovoltaic Effect of CdS/Si-NPA Nanoheterojunction Array,TM914.4
  20. Synthesis and Photoluminescence Properties of Aligned ZnO Nanowire Arrays by Hydrothermal Synthesis Method,TB383.1
  21. Hydrothermal Synthesis and Photoluminescence Properties of Managanese Doped-ZnS Nanoparticles,TB383.1

CLC: > Mathematical sciences and chemical > Chemistry > Inorganic Chemistry > Chemical elements and inorganic compounds > Inorganic synthetic chemistry
© 2012 www.DissertationTopic.Net  Mobile