Enhanced Thermoelectric Performance of Cu-incorporated Bi0.5Sb1.5Te3 by Melt Spinning and Spark Plasma Sintering
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Incorporation of a foreign element is considered as a promising approach to enhance the performance of thermoelectric materials since this can either improve the power factor by a band structure modification or reduce the thermal conductivity by a phonon scattering strengthening. We fabricated the polycrystalline bulk samples of Cu-incorporated Bi0.5Sb1.5Te3 by melt spinning and spark plasma sintering, and evaluated the electronic and thermal transport properties. From the phase analysis and thermoelectric properties measurement, we found that most of the added excess Cu atoms were substituted at a Sb-site and a small amount of Cu was intercalated at the van der Waals gap between quintuple layers. By the formation of two different point defects (substituted Cu and intercalated Cu), the thermoelectric power factor was enhanced because of the increased density of states effective mass, and simultaneously reduced thermal conductivity originated from the intensified phonon scattering and suppressed bipolar contribution. Maximum thermoelectric figure of merit zT of 1.13 was obtained at 400 K.
KeywordsThermoelectric Cu-incorporation Bi0.5Sb1.5Te3 melt spinning spark plasma sintering
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This study was supported by a grant from the Korean National Research Funds (NRF-2019R1C1C1005254). This work was supported by the HongikUniversity newfaculty research support fund. This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by theMinistry of Education (NRF-2019R1A6A1A11055660).
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