科研之友
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摘要
Thermoelectric materials are the leading candidate today for applications in solid-state waste-heat recovery/cooling applications. Research and engineering has pushed the ZT, and overall conversion efficiency, of these materials to values which can be deemed practical for commercialization. However, many of the state-of-the-art thermoelectric materials of today utilize elements which are toxic, such as Ag, Pb, Tl, and Cd. Alloys of GeTe and Sb2Te3 were first explored for their applications in phase-change memory, because of their ability to rapidly alternate between crystalline and amorphous phases. Recently, these materials have been identified as materials with ZT (S (2) T/rho kappa, where S is the Seebeck coefficient, rho is the electrical resistivity, T is the operating temperature, and kappa is the thermal conductivity) much greater than unity. In this work, the influence of elemental Ge as a secondary phase on transport in Ge17Sb2Te20 was explored. It was found that Ge introduces an additional scattering mechanism, which leads to increased electrical resistivity, Seebeck coefficient, and power factor values as high as 36 mu W cm(-1) K-2. The thermal conductivity was slightly reduced and the ZT was enhanced across the entire temperature range of measurement, with peak values greater than 2.
- 出版日期2017-5
