Synergistic modulation of mobility and thermal conductivity in (Bi,Sb)2Te3 towards high thermoelectric performance†,Energy & Environmental Science

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Synergistic modulation of mobility and thermal conductivity in (Bi,Sb)2Te3 towards high thermoelectric performance†
Energy & Environmental Science ( IF 32.4 ) Pub Date : 2018-12-12 00:00:00 , DOI: 10.1039/c8ee03225d
Yu Pan _{1,

2,

3,

4,

5} , Yang Qiu _{6,

7,

8,

9} , Ian Witting _{10,

11,

12,

13} , Liguo Zhang _{14,

15,

16} , Chenguang Fu _{14,

15,

16} , Jing-Wei Li _{1,

2,

3,

4,

5} , Yi Huang _{6,

7,

8,

9} , Fu-Hua Sun _{1,

2,

3,

4,

5} , Jiaqing He _{6,

7,

8,

9} , G. Jeffrey Snyder _{10,

11,

12,

13} , Claudia Felser _{14,

15,

16} , Jing-Feng Li _{1,

2,

3,

4,

5}

Affiliation

State Key Laboratory of New Ceramics and Fine Processing
School of Materials Science and Engineering
Tsinghua University
100084 Beijing
P. R. China
Department of Physics
South University of Science and Technology of China
Shenzhen 518055
China
Department of Materials Science and Engineering
Northwestern University
Evanston
USA
Max Planck Institute for Chemical Physics of Solids
Dresden
Germany

Modulating microstructures in a wide range from atomic defects to microscale structures independently can partially decouple the transport of charge carriers and phonons and thus enhance the figure of merit (zT) of thermoelectric materials. High mobility requires atomic scale purity, while introducing nanoscopic inhomogeneities leads to low thermal conductivity. Through a two-step sintering process with excess Te, lower reduction of mobility and decreased thermal conductivity were simultaneously achieved in (Bi,Sb)₂Te₃. Grain boundaries and defects that strongly impede charge carrier transport are reduced by the two-step sintering process leading to a higher mobility compared to that of the one-step sintered bulk. At the same time, removal of Te as well as Sb-rich inhomogeneities with lattice misfit to the matrix decreased the thermal conductivity. In this way, simultaneous maintenance of high mobility and low lattice thermal conductivity was illustrated. By further optimization of carrier concentration, the produced material showed an encouraging zT value of 1.38 at 323 K. The present work demonstrates a method for synthesizing high-efficiency thermoelectric materials through simultaneous optimization of the electrical and thermal transport properties.

中文翻译：

（Bi，Sb）₂ Te _3中的迁移率和热导率对高热电性能的协同调制†

从原子缺陷到微观结构，广泛地调节微观结构可以部分解耦电荷载流子和声子的传输，从而提高热电材料的品质因数（zT）。高迁移率要求原子级纯度，而引入纳米级不均匀性则会导致低导热性。通过两步烧结过程，使用了过量的Te，在（Bi，Sb）₂ Te ₃中同时实现了迁移率的降低和导热系数的降低。。通过两步烧结工艺可减少严重阻碍电荷载流子传输的晶界和缺陷，从而与单步烧结块相比具有更高的迁移率。同时，除去Te以及富含Sb的不均匀性（晶格不适合基体）会降低热导率。以这种方式，说明了同时保持高迁移率和低晶格热导率。通过进一步优化载流子浓度，制得的材料在323 K处显示出令人鼓舞的zT值1.38。本工作证明了通过同时优化电和热传输特性来合成高效热电材料的方法。

更新日期：2018-12-12

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