Effect of Excess Na on the Morphology and Thermoelectric Properties of Na (x) Pb1-x Te0.85Se0.15
- 주제(키워드) Thermoelectrics , PbTe , power factor , precipitates
- 등재 SCIE, SCOPUS
- 발행기관 SPRINGER
- 발행년도 2014
- 총서유형 Journal
- URI http://www.dcollection.net/handler/ewha/000000086905
- 본문언어 영어
- Published As http://dx.doi.org/10.1007/s11664-013-2872-9
초록/요약
The thermoelectric properties of p-Na (x) Pb1-x Te0.85Se0.15, which possesses a high thermoelectric figure of merit due to band convergence, have been systematically investigated for increasing Na concentration (x = 0.01, 0.02, 0.03, 0.05, and 0.07) from room temperature to 773 K. For x values up to 0.03, the hole concentration increases with the Na concentration; however, for x a parts per thousand yen 0.03, excess Na forms separate microstructures with needle- and plate-like shapes. At high concentrations (x = 0.05 and 0.07) both the number and size of these structures increase (over 10 mu m). Differential scanning calorimetry identifies a phase change near 660 K in samples with x = 0.05 and 0.07, confirming the formation of microstructures; this phase change leads to a decrease in electrical resistivity. However, these microstructures do not significantly affect thermal transport, probably because they are too large to scatter phonons. The highest thermoelectric figure of merit, zT, value is 1.6, which is obtained at 760 K for x = 0.05, due to the low thermal conductivity and electrical resistivity.
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