Ioffe-Regel limit and lattice thermal conductivity reduction of high performance (AgSbTe2)15(GeTe)85 thermoelectric materials
Ioffe-Regel limit and lattice thermal conductivity reduction of high performance (AgSbTe2)15(GeTe)85 thermoelectric materials
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高性能(AgSbTe2)15(GeTe)85热电材料的Ioffe-Regel极限和晶格热导率降低
DOI：
10.1039/c3ta15147f
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发表时间：
2014-01-01
影响因子：
11.9
通讯作者：
Zhao, Xinbing
中科院分区：
文献类型：
--
作者：
Zhu, Tiejun;Gao, Hongli;Zhao, Xinbing
研究了高性能（AgxSbTex/2+1.5）（15）（GeTe）（85）（TAGS-85）（x - 0.4-1.2）热电合金的输运特性。结果表明，TAGS-85材料的载流子平均自由程与晶格常数相当，表明该体系已达到最小迁移率Ioffe-Regel极限，进一步减小晶粒尺寸不会影响迁移率，同时有利于热导率的降低.通过熔融纺丝制备的细晶样品证实了这一假设。熔体纺丝样品的载流子迁移率和平均自由程确实与粗晶粒样品的载流子迁移率和平均自由程相当，而晶格热导率由于边界的增加和声子散射而被有效地抑制。熔纺细晶样品的ZT接近1.6，ZT >1.2的温度范围明显扩大，这对未来的应用是非常鼓舞人心的。
The transport characteristics of high performance (AgxSbTex/2+1.5)(15)(GeTe)(85) (TAGS-85) (x - 0.4-1.2) thermoelectric alloys are investigated. It is found that the carrier mean free path of TAGS-85 materials is comparable to the lattice parameter, indicating that this system has reached the minimum possible mobility, the Ioffe-Regel limit, and that further reduction of grain size will not affect the mobility while benefiting to the thermal conductivity reduction. The fine-grained samples are prepared by melt spinning to corroborate the supposition. The carrier mobility and mean free path of melt spun samples are indeed comparable with those of coarse-grained samples, while the lattice thermal conductivity is suppressed effectively as a result of the increasing boundaries and hence phonon scattering. A state-of-the-art ZT of similar to 1.6 is obtained for the melt-spun fine-grained samples and the temperature region of ZT >1.2 has been broadened notably, which is pretty encouraging for the future applications.