Enhanced atomic ordering leads to high thermoelectric performance in AgSbTe2

High thermoelectric performance is generally achieved through either electronic structure modulations or phonon scattering enhancements, which often counteract each other. A leap in performance requires innovative strategies that simultaneously optimize electronic and phonon transports. We demonstrate high thermoelectric performance with a near room-temperature figure of merit, ZT similar to 1.5, and a maximum ZT similar to 2.6 at 573 kelvin, by optimizing atomic disorder in cadmium-doped polycrystalline silver antimony telluride (AgSbTe2). Cadmium doping in AgSbTe2 enhances cationic ordering, which simultaneously improves electronic properties by tuning disorder-induced localization of electronic states and reduces lattice thermal conductivity through spontaneous formation of nanoscale (similar to 2 to 4 nanometers) superstructures and coupling of soft vibrations localized within similar to 1 nanometer around cadmium sites with local strain modulation. The strategy is applicable to most other thermoelectric materials that exhibit inherent atomic disorder.

Automated summary

By optimizing atomic disorder and cadmium doping in polycrystalline silver antimony telluride, high thermoelectric performance with near room-temperature figure of merit ZT of around 1.5 and maximum ZT of around 2.6 at 573 kelvin is achieved. This strategy of enhancing cationic ordering while reducing lattice thermal conductivity is applicable to most thermoelectric materials with inherent atomic disorder.