Formation of multiple phases is considered an effective approach for enhancing the performance of thermoelectric materials since it can reduce the thermal conductivity and improve the power factor. Herein, we report the in-situ generation of a submicron-scale (500 nm) heterograin structure in p-type Yb-filled (Fe,Co)4Sb12 skutterudites during the melt spinning process. Mixed grains of YbxFe3-yCo1+ySb12 and YbzFe3+yCo1-ySb12 were formed in melt spun ribbons due to uneven distribution of cations. By the formation of interfaces between two different grains, the power factor was enhanced due to the formation of an energy barrier for carrier transport, and simultaneously the lattice thermal conductivity was reduced due to the intensified boundary phonon scattering. A high thermoelectric figure of merit zT of 0.66 was obtained at 700 K.
Bibliographical noteFunding Information:
Funding: This research was supported by the Basic Science Research Program (NRF-2017R1D1A1A09000570) and by a grant from the Industrial Core Technology Development Program (10083640). This research was also supported by Low-dimensional Materials Genome Development by Korea Research Institute of Standards and Science (KRISS—2018—18011084). This paper was partially supported by the Graduate School Research Program of KOREATECH. And thanks the Cooperative Equipment Center at KOREATECH for assistance with SEM XRD analysis.
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All Science Journal Classification (ASJC) codes
- Materials Science(all)