Development of High ZT Thermoelectric Materials with Nanostructure for Energy Applications
Abstract
Three subtasks were performed in this research study and the respective findings are described here. A) Investigation of the system of surface modified nanostructured bulk: Our studies show that the CuFeSe2 thin film on Si (or SiO2) substrates exhibit large thermal power in the order of 1300 microvolt/K at approximately 300K. We conclude that the thinner films have the higher thermal conductivity. At 300K, the magnitude of thermal conductivity 8.8 W/m-K for 200 nm is about two times larger than 1.7 W/m-K of the 800 nm film. The consequence is attributed to the better crystallization in thinner films. This film thickness dependence of crystallization was confirmed by X-ray diffraction data. In this report, the thermal resistance of the interface boundaries in SiNx-CuFeSe2 was estimated to be 3.32 x 10(-8) Km2/W. We cannot give a clear estimate of the ZT value for these films at the moment. The major difficulty came from the exact value of the thermoelectric power of the thin film. B) Investigation of one-dimensional nanowires: Bismuth telluride film and nanowires array (embedded in alumina template) were fabricated by potentiostatically electrodeposition. The Seebeck coefficient, electrical resistivity and thermal conductivity of a single nanowire provide an estimated thermoelectric figure of merit ZT = 0.45 at 300 K and likely to reach beyond 0.9 above 350 K, for Bi2Te3 nanowires. C) Directional dependent thermal conductivity and thermal rectifier: we cannot make a conclusive statement that there exists no rectification effect, as the narrowest section in our device is still too big compared with that observed in carbon and boron nitride nanotubes.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 03, 2010
- Accession Number
- ADA514881
Entities
People
- Maw-kuen Wu
- Yang-yuan Chen