A Novel Chemical Route for Bi2Se3/TiO2, SiO2 or Polyaniline Nanocomposites

• Main Authors: Feng-Li Chang, 張逢立
• Other Authors: Shu-Chuan Huang
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/99756546434803117240

碩士 === 國立東華大學 === 化學系 === 93 === Abstract Bi2Se3 and Bi2Te3 are layered, thermoelectrical materials used at room temperature. and their improvement in thermoelectric properties is of great importance. Earlier theoretical work has shown that the thermoelectric figure merit of low dimensional Bi2Se3/Bi2Te3 can be enhanced up to three times higher than that of the bulk materials. We have succeeded in reducing its dimension by intercalating nano-TiO2, -SiO2 or -polyaniline into the gallery of Bi2Se3. The driving force for the formation of these nanocomposites is the Coulombic interaction between positive and negative particles. Bi2Se3 layers carry negative charges; and TiO2, SiO2 or polyaniline carry poaitive charges. These nanocomposites are characterized by Zetasizer, XRD, TEM, TGA, Mass, and thermal / electrical conductivity measurements. The Zetasizer shows that the Zeta potential of exfoliated Bi2Se3 is around -40 mV. And, the higher the concentration of suspended Bi2Se3, the weaker the Zeta potential. The XRD reveals the d-spacing of Bi2Se3 being expanded from 2.82 nm to 4.38 nm, and 6.86 nm upon intercalation of TiO2, SiO2 particles respectively. As for the case nanopolyaniline-intercalated Bi2Se3, the gallery height is increased to 4.35 nm. The TEM shows that the diameter of the free TiO2 particles are about 80 nm, and that of nanopolyaniline particles are of 30 nm. The diameter of TiO2 intercalated particles is about 1.5 nm, which is much smaller than that of free TiO2 particles.