| Summary: | 碩士 === 國立高雄應用科技大學 === 化學工程與材料工程系 === 98 === In this study, we have synthesized the bismuth telluride powder by hydrothermal and solvothermal method and investigated the thermoelectric properties. By using Te powder and BiCl3 as starting materials, EDTA as the chelating agent and NaBH4 as reducing agent for synthesis Bi2Te3 powder at different reaction temperature and time and investigation the physical properties of materials by XRD, SEM, TEM, etc. Preparation of bulk bismuth telluride by sintering and measure the Seebeck coefficient, thermal conductivity and resistivity. By the XRD analysis results, showed that Bi4Te3 transform into Bi2Te3 crystalline phase at hydrothermal reaction temperature of 140℃. Studies on the morphology and microstructure of the products from hydrothermal and solvothermal methods respectively, which displayed bar and irregular polygon by SEM and TEM.
After uniaxial compressed and calcined at temperature of 300℃, the samples results of thermoelectric properties showed that hydrothermal reaction temperature at 180℃ for 24h and solvothermal reaction temperature at 180℃ for 16h, the 300K Seebeck coefficient is -143 μV / K, -230μV / K and thermal conductivity is 0.49W/mK, 0.41W/mK, respectively. Finally, obtain the doped carbon nanotubes commercial that improve the thermoelectric properties.
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