Realizing N-type SnTe Thermoelectrics with Competitive Performance through Suppressing Sn Vacancies
Realizing N-type SnTe Thermoelectrics with Competitive Performance through Suppressing Sn Vacancies
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DOI：
10.1021/jacs.1c02346
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发表时间：
2021-06-02
影响因子：
15
通讯作者：
Zhao, Li-Dong
中科院分区：
文献类型：
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作者：
Pang, Huimei;Qiu, Yuting;Zhao, Li-Dong
由于自身丰富的Sn空位，开发n型SnTe热电材料是一个很大的挑战。本文通过抑制Sn空位，再进行电子掺杂，成功合成了性能优异的n型SnTe热电材料。Pb合金通过在SnTe中填充Sn空位显著抑制了Sn空位（透射电镜支持），并且通过I掺杂引入电子将电输运从p型转变为n型。在n型SnTe中，我们发现Pb合金化后，通过锐化导带增加载流子迁移率可以提高电导率，而Pb合金化和I掺杂引入缺陷后，通过强声子散射可以降低晶格热导率。由于这些增强，n型Sn0.6Pb0.4Te0.98I0.02在573 K时达到了0.8的ZT(max)，在300-823 K时达到了0.51的ZT(ave)，可以与许多优秀的p型SnTe相匹配。这项工作表明，n型SnTe可以通过实验获得，并且是热电发电的有希望的候选者，这将刺激基于n型和p型SnTe腿的n型SnTe热电材料甚至器件的进一步研究。
Due to the intrinsically plentiful Sn vacancies, developing n-type SnTe thermoelectric materials is a big challenge. Herein, n-type SnTe thermoelectric materials with remarkable performance were successfully synthesized through suppressing Sn vacancies, followed by electron-doping. Pb alloying notably depressed the Sn vacancies via populating Sn vacancies in SnTe (supported by transmission electron microscopy), and the electrical transports were shifted from p-type to n-type through introducing electrons using I doping. In the n-type SnTe, we found that the electrical conductivity could be enhanced by increased carrier mobility through sharpening conduction bands after alloying Pb, while the lattice thermal conductivity could be reduced via strong phonon scattering after introducing defects by Pb alloying and I doping. Resulting from these enhancements, the n-type Sn0.6Pb0.4Te0.98I0.02 achieves a notably high ZT(max) similar to 0.8 at 573 K and a remarkable ZT(ave) similar to 0.51 at 300-823 K, which can match many excellent p-type SnTe. This work indicates that n-type SnTe could be experimentally acquired and is a promising candidate for thermoelectric generation, which will stimulate further research on n-type SnTe thermoelectric materials and even devices on the basis of both n- and p-type SnTe legs.