Realizing the High Thermoelectric Performance of GeTe by Sb-Doping and Se-Alloying

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• 作者：Juan Li ; Xinyue Zhang ; Siqi Lin ; Zhiwei Chen ; Yanzhong Pei
• 刊名：Chemistry of Materials
• 出版年：2017
• 出版时间：January 24, 2017
• 年：2017
• 卷：29
• 期：2
• 页码：605-611
• 全文大小：510K
• ISSN：1520-5002

文摘

GeTe-based alloys have been intensively considered as p-type thermoelectrics for about 50 years, yet existing literature barely discussed the thermoelectric properties of pristine GeTe at high temperatures (300–800 K). This work first backs to a fundamental understanding on the thermoelectric transport properties inherent to p-type GeTe, based on more than 50 samples synthesized with expected carrier concentrations ranging from 1 × 10²⁰ to 3 × 10²¹ cm^–3. A thermoelectric figure of merit zT as high as ∼1.7 is found inherent to this compound when it is optimally doped with a Hall carrier concentration of 2.2 ± 10% × 10²⁰ cm^–3, offering a reference substance to expose the origins for the high zT in historical GeTe-based alloys. Guided by the above knowledge, further alloying Te with Se in samples with an optimal carrier concentration enables a reduction on the lattice thermal conductivity by ∼40% and eventually leads to a further enhancement on zT (up to 2.0) by ∼20%. This work demonstrates not only GeTe as an inherently high performance thermoelectric matrix compound but also its availability for further improvements by additional strategies.