|About this Abstract
||2021 TMS Annual Meeting & Exhibition
||Alloys and Compounds for Thermoelectric and Solar Cell Applications IX
||Self-tuning of Carrier Type and Improved Thermoelectric Performance in Skutterudite CoM1.5Te1.5 (M = Sn or Ge)
||Li-Chyong Chen, Suneesh MV, Ta-Lei Chou, Kuei-Hsien Chen
|On-Site Speaker (Planned)
CoSb3-based skutterudites can realize the “phonon glass electron crystal” concept, capable of manipulating electrical and thermal transports independently. The skutterudite compounds possess caged structure in which a filler atom vibrates with large amplitude. The anharmonic vibration of the filler atom scatters the phonons effectively while maintaining relatively high carrier mobility through the caged network. Further reduction in thermal conductivity could be achieved by modifying the pnicogen Sb4 ring. In this present work, we iso-electronically replace the Sb4 ring with M2Te2 (M=Sn or Ge), by mechano-chemical ball-milling plus hot pressing and, as revealed by Seebeck coefficient, the sample can be either n- or p-type semiconductors, depending on the Te/Sn ratio. Meanwhile, this approach raises the carrier concentration, conductivity and thereby thermoelectric power factor. Eventually, with thermal conductivity as low as ~2 W/m-K, we boost the dimensionless figure of merit of CoM1.5Te1.5 50 times higher to 0.6 at 773 K.
||Electronic Materials, Characterization, Other