Microstructure and Thermoelectric Properties of (Bi, Te, S) Composites
| Autor: | Jing-Yao Li, 李景耀 |
|---|---|
| Rok vydání: | 2016 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 104 In this study, the (Bi2S3)x/(Bi2Te3)1- x eutectic composites with x=0.03, 0.05, 0.07, 0.10, 0.15 were prepared by melting and quenching method. The compositions, phases, and microstructures of the synthesized materials were analyzed by X-ray diffraction analysis (XRD), field emission scanning electron microscope (FE-SEM) and transmission electron microscopy (TEM). The thermoelectric properties were analyzed by means of electrical and thermal transport measurement in the temperature range of 50 - 300 K, and the figure of merit ZT was calculated to evaluate the thermoelectric properties. The composition, phase asemblage, and temperature dependence of the thermoelectric properties of (Bi2S3)x/(Bi2Te3)1- x composites were discussed. The experimental results show that all synthesiged samples are composites with the microstructures consisting of layer intergrowths of Te, Bi2Te3 and Bi2Te2S. As compared to the pure Bi2Te3, these composites exhibit considerably better mechanical strength and toughness. These composites are n-type semiconductors. The Seebeck coefficient increases monotonically with the x value, and the electrical resistivity increases with the increasing temperature for all samples. Among all compositions, (Bi2S3)0.07 /(Bi2Te3)0.93 sample has the lowest thermal conductivity, because of its finest layer structure, and hence the best ZT value of 0.13 at 300 K. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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