Synthesis and characterization of semiconductor nanomaterials for thermoelectric applications

Open Access
Author:
Dirmyer, Matthew R
Graduate Program:
Chemistry
Degree:
Doctor of Philosophy
Document Type:
Dissertation
Date of Defense:
June 25, 2009
Committee Members:
  • Ayusman Sen, Dissertation Advisor
  • Ayusman Sen, Committee Chair
  • John V Badding, Committee Member
  • David Lawrence Allara, Committee Member
  • James Patrick Runt, Committee Member
Keywords:
  • nanomaterials bismuth telluride antimony telluride
Abstract:
In this dissertation, I explore simple chemical means to produce various nanomaterials. In Chapter 2, the synthesis of size-tuned bismuth telluride nanoparticles is discussed. The solution phase synthesis of bismuth telluride nanoparticles has been accomplished in the presence of a library of thiols as the capping ligand. These crystalline nanostructures range in size from ∼20 to ∼100nm with a relatively narrow size dispersity. Size and shape of the resulting nanostructures has been investigated as a function of chain length of the thiol and temperature. An investigation into the thermoelectric properties of the nanostructures shows promising electrical conductivity, thermopower, and thermal conductivity for undoped bismuth telluride. In Chapter 3, a soluble precursor for antimony telluride is described. This precursor was used to fabricate semiconductor nanowires of varying diameter and thin films through simple templatingmethods. Electrical conductivity and thermoelectric power measurements of these films are only slightly lower than for antimony telluride films fabricated by vacuum deposition. In Chapter 4, the polytetrafluoroethylene (PTFE)/metal nanocomposites are discussed. Palladium and nickel PTFE nanocomposites were made by impregnation of the polymer with metal acetates. Annealing and jet blowing of these materials form PTFE nanofiber/metal nanoparticle composites.