Rapid preparation of Ge0.9Sb0.1Te1+x via unique melt spinning: Hierarchical microstructure and improved thermoelectric performance

Thermoelectric semiconductors based on GeTe has been proved to be an important materials for converting waste heat into electricity. In this study, we demonstrate an enhancement of thermoelectric performance for p-type Ge_0.9Sb_0.1Te_1+x by a unique melt spinning method combined with hot pressing (MS-HP), through which increased Seebeck coefficients and reduced thermal conductivities are achieved simultaneously. Moreover, the MS technique greatly gives rise to a variety of microstructures, such as the fine Ge precipitates, twins and nano-domains, all of which contribute to the significantly reduced thermal conductivities. Finally, the Ge_0.9Sb_0.1Te_1.03 reaches a maximum zT value of ∼1.9 at 760 K and a giant average zT of ∼1.2 between 300 K and 820 K, which is comparable to the reported results for GeTe based materials. Combined with the rapid fabrication, Ge_0.9Sb_0.1Te_1+x prepared by melt spinning process is an attractive p-type material for thermoelectric power generation application.