Effect of Ce-Doping on Thermoelectric Properties
in PbTe Alloys Prepared by Spark Plasma Sintering |
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Authors: | JQ Li SP Li QB Wang L Wang FS Liu WQ Ao |
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Affiliation: | (1) Department of Materials Science, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou, 310027, People’s Republic of China;(2) Department of Applied Chemistry, Harbin Institute of Technology, Harbin, 150001, People’s Republic of China |
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Abstract: | Ce-doped Pb1−x
Ce
x
Te alloys with x = 0, 0.005, 0.01, 0.015, 0.03, and 0.05 were prepared by induction melting, ball milling, and spark plasma sintering techniques.
The structure and thermoelectric properties of the samples were investigated. X-ray diffraction (XRD) analysis indicated that
the samples were of single phase with NaCl-type structure for x less than 0.03. The lattice parameter a increases with increasing Ce content. The lower Ce-doped samples (x = 0.005 and 0.01) showed p-type conduction, whereas the pure PbTe and the higher doped samples (x = 0, 0.015, 0.03, and 0.05) showed n-type conduction. The lower Ce-doped samples exhibited a much higher absolute Seebeck coefficient, but the higher electrical
resistivity and higher thermal conductivity compared with pure PbTe resulted in a lower figure of merit ZT. In contrast, the higher Ce-doped samples exhibited a lower electrical resistivity, together with a lower absolute Seebeck
coefficient and comparable thermal conductivity, leading to ZT comparable to that of PbTe. The lowest thermal conductivity (range from 0.99 W m−1 K−1 at 300 K to 0.696 W m−1 K−1 at 473 K) was found in the alloy Pb0.95Ce0.05Te due to the presence of the secondary phases, leading to a ZT higher than that of pure PbTe above 500 K. The maximum figure of merit ZT, in the alloy Pb0.95Ce0.05Te, was 0.88 at 673 K. |
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