A cubic room temperature polymorph of thermoelectric TAGS-85.

ABSTRACT: The alloy (GeTe)₈₅(AgSbTe₂)₁₅, commonly known as TAGS-85, is one of the best performing p-type thermoelectric materials in the temperature range 200-500 °C. In all reports thus far, TAGS-85 adopts a rhombohedral crystal structure at room temperature and undergoes a reversible transition to a cubic phase in the middle of the operating temperature range. Here, we report on a novel, metrically cubic polymorph of TAGS-85 that can be obtained at room temperature using a particular cooling protocol during initial synthesis. This polymorph transforms irreversibly on initial heating to a 21-layer trigonal structure containing ordered cation vacancy layers, driven by the spontaneous precipitation of argyrodite-type Ag₈GeTe₆. We show that the pr

SUBMITTER: Kumar A 

PROVIDER: S-EPMC9092272 | biostudies-literature | 2018 Dec

REPOSITORIES: biostudies-literature