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Enhancement in thermoelectric properties of Te-embedded Bi2Te3 by preferential phonon scattering in heterostructure interface
Nano Energy ( IF 16.8 ) Pub Date : 2018-03-07 , DOI: 10.1016/j.nanoen.2018.03.009
Hyejin Choi , Kwangsik Jeong , Jimin Chae , Hanbum Park , Juheyuck Baeck , Tae Hyeon Kim , Jae Yong Song , Jaehun Park , Kwang-Ho Jeong , Mann-Ho Cho

A comprehensive understanding of the nano-structural effects that cause reduction in thermal conductivity represents important challenges for the development of thermoelectric materials with an improved figure of merit ZT. Bismuth telluride (Bi2Te3)-based thermoelectric materials exhibit very low levels of thermal conductivity. In this study, a Te crystal-embedded Bi2Te3 (Te–Bi2Te3) thin film was formed by establishing a specific annealing temperature for a Te-rich Bi/Te multilayered structure. Modulations in structure and composition were observed at the boundaries between the two phases of Te and Bi2Te3. Furthermore, the samples contained regularly shaped nanometer-scale Bi2Te3 single grains. Therefore, we obtained a dramatic ZT value of 2.27 (+ 0.04, − 0.08) at 375 K from the Te–Bi2Te3 thin film. Finally, we confirmed that interface phonon scattering between the Te–Bi2Te3 boundaries plays an important role in inter-grain phonon transport, which results in a reduction in the lattice thermal conductivity.



中文翻译:

通过异质结构界面中的优先声子散射增强Te嵌入的Bi 2 Te 3的热电性能

对导致导热系数降低的纳米结构效应的全面理解,对开发具有优异品质因数ZT的热电材料构成了重大挑战。碲化铋(Bi 2 Te 3)基热电材料的导热系数非常低。在这项研究中,通过为富Te的Bi / Te多层结构确定特定的退火温度,形成了嵌入Te晶体的Bi 2 Te 3(Te–Bi 2 Te 3)薄膜。在Te和Bi 2 Te 3两相之间的边界处观察到结构和组成的调节。此外,样品包含规则形状的纳米级Bi 2 Te 3单晶粒。因此,我们从Te–Bi 2 Te 3薄膜在375 K下获得了惊人的ZT值2.27(+ 0.04,-0.08)。最后,我们证实了Te–Bi 2 Te 3边界之间的界面声子散射在晶间声子传输中起着重要作用,这导致了晶格热导率的降低。

更新日期:2018-03-07
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