Dissertation > Excellent graduate degree dissertation topics show

Study on Preparation and Nb-doped of TiO2 Thin Film by Sol-Gel Method

Author: WangGuoQing
Tutor: LiuXueQin
School: Lanzhou University
Course: Condensed Matter Physics
Keywords: Titanium dioxide film Sol - gel Phase change Nb-doped Optical properties
CLC: O484.1
Type: Master's thesis
Year: 2011
Downloads: 111
Quote: 0
Read: Download Dissertation

Abstract


In recent years, the increasingly serious environmental pollution, researchers take this as an opportunity to start a semiconductor material used in photocatalytic degradation of pollutants, and to open up its application in the field of environmental pollution control. These semiconductor materials, TiO2 has a stable, non-toxic and inexpensive and so aroused great interest. TiO2 photocatalytic activity of crystal structure, the Ti02 crystal structure is influenced by many factors, including including the preparation method, doping elements. Based on this, using the sol-gel method undoped and Nb-doped TiO2 film. Elements Nb and Ti element adjacent sub-group elements. They have similar ionic radius (of Nb5: 0.70 (?), And Ti: 0.68 (?)). Nb5 can easily access to the bit of TiO2 crystal lattice. The valence electron of Nb more than Ti a doping of Nb capable of changing the carrier concentration in the TiO2 film. Therefore, we have chosen Nb-doped. In this paper, we study the influence of Nb on the film structure and the phase transition temperature, and also studied the band gap and transmittance of the film. Research progress and results are as follows:. Undoped TiO2 thin films were prepared using the sol-gel method, by optimizing the test parameters in order to obtain a continuous, dense and uniform surface Ti02 film. The annealing of 800 ° C and below, the film of anatase. When the annealing temperature of 900 ° C, the same anatase and rutile and anatase dominant. Analysis of optical properties of undoped TiO2 film transmittance in the visible region of about 65% on average. When the annealing temperature of 500 ℃ C the Ti02 film optical bandwidth is 3.25eV, when the annealing temperature increased to 800 ° C, the optical band gap of the TiO2 film is reduced to 3.19eV. 2 using the sol-gel method Nb-doped Ti02 film. Nb-doped Ti02 film when the annealing temperature is below 800 ° C, the film mainly anatase phase. XRD and Raman analysis shows that The Nb doping inhibit the growth of anatase nanocrystals. When the annealing temperature of 700-C, the undoped forbidden band width of Ti02 film is 3.21eV, while the Nb doping the Ti02 film band gap with the Nb doping concentration increases, when the Nb doping concentration of 6 at.% Ti02 film bandgap of 3.32eV, this can be explained by Burstein-Moss (BM) effect BM effect considered when the conduction band of the low power level is electronically filled ACT, transition can only occur in than Fermi energy level higher energy level. Therefore, Nb doped widened the Ti02 film bandgap As Nb doping concentration increases. 3 Nb doping concentration of not less than 4 at.% Ti02 film 900 ° C annealing can be obtained rutile Ti02 film. This result indicates that Nb can promote the phase transition the Ti02 from anatase to rutile at high temperatures. Annealing of 900 ° C, Nb-doped the Ti02 film transmittance in the visible region of about 60 percent. The band gap of TiO2 films with Nb doping concentration increases slightly larger in the smaller first.

Related Dissertations

  1. Preparation and Photocatalytic Properties for Water Decomposition of Titanate Photocatalyst,O643.36
  2. Preparation of ITO Quai-1D Nanostructures by Sol-Gel Method Combined with Porous Anodic Aluminum Oxide Template,TB383.1
  3. Study on the Synthesis Bi3.25La0.75Ti3O12（BLT） Nanotubes and Nano Wires,TB383.1
  4. Preparation and Electrocaloric Effect of BaxSr1-xTiO3 Ferroelectric Thin Films,TB383.2
  5. Study on Coupled Radiation-Phase Change Heat Transfer in Semi-Transparent Materials,V259
  6. Preparation and Performance of V2O5-WO3/MOx/Cordierite Catalyst Modified with Cu、Mn、Ce for DeNOx,X701
  7. Iron, lanthanum -doped nano TiO \u003csub\u003e 2 \u003c/ sub\u003e Preparation and photocatalytic properties,O614.411
  8. Optical Properties of Chlorphyll-a in Reservoir Water and Its Concentration Inversion Models by Remote Sensing,S127
  9. Cobalt Ferrite and Its Performance,O611.4
  10. First-principles study of the structure and optical properties of the high-pressure alkali metal (Li, Na, K),O521.2
  11. Synthesis, Conformation and Character of W/Cu/S Supermolecule Clusters Containing Tp~* Group,O611.4
  12. Construction, Characterization and Properties of Tp~*-Containing W/S/Cu Clusters,O611.4
  13. Preparation of Silica Hollow Spheres with Mesopores in the Walls,TB383.1
  14. Fabrications and Applications of Microelectrode Array of Silicon Dioxide Cavities and Magnetic Ferroferric Oxide Nano-Bioconjunctions,TB383.1
  15. Study on Preparation and Properties of Polyimide/SiO2 Hybrid Films,TB383.2
  16. Research on the Synthesis of the Pr-zircon Yellow Pigments and the Ceratmic Ink,TQ622.1
  17. The Research on Preparation Technology and Sintering Behavior of Rare Earth Aluminates (Dy3Al5O12、 NdAlO3、LaAl11O18),TB383.3
  18. Studies of High Refractive Index Materials Prepared by Nano ZrO2 and TiO2 Hybrid Silicone Epoxy Resin,TB383.1
  19. Preparation and Characterization of Al2O3/C Hybrid Aerogels and Al2O3 Aerogels,O648.17
  20. Two-dimensional Tunable Bandgap Photonic Crystals Based on VO2 Phase Transition,O734
  21. Preparation and Characteristic of BiFeO3 /Bi3.25 La 0.75 Ti3O12 Multiferroic Bi-layer Films,O484.4

CLC: > Mathematical sciences and chemical > Physics > Solid State Physics > Thin Film Physics > Film growth,structure and epitaxy
© 2012 www.DissertationTopic.Net  Mobile