Enhanced Thermoelectric Properties in the Counter-Doped SnTe System with Strained Endotaxial SrTe

摘要

We report enhanced thermoelectric performance in SnTe, where significantly improved electrical transport properties and reduced thermal conductivity were achieved simultaneously. The former was obtained from a larger hole Seebeck coefficient through Fermi level tuning by optimizing < 0.2 the carrier concentration with Ga, In, Bi, and Sb dopants, resulting in a power factor of mu W cm(-1) K-2 and ZT of 0.9 at 823 K in Sn0.97Bi0.03.Te.. To reduce the lattice thermal conductivity without deteriorating the hole carrier mobility in Sn0.97Bi0.03Te, SrTe was chosen as the second phase to create strained endotaxial nanostructures as phonon scattering centers. As a result, the lattice thermal conductivity decreases strongly from similar to 2.0 Wm(-1) K-1 for Sn0.97Bi0.03Te to X1.2 Wm(-1) as the SrTe content is increased from 0 to 5.0% at room temperature and from similar to 1.1 to -,0.70 Wm-1 IC' at 823 K. For the Sn0.97Bi0.03Te-3% SrTe sample, this leads to a ZT of 1.2 at 823 K and a high average ZT (for SnTe) of 0.7 in the temperature range of 300-823 K, suggesting that SnTe is a robust candidate for medium temperature thermoelectric applications.

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