接近拓绝缘状态导致n型PbTe的高热电性能
Yu Xiao1, Dongyang Wang1, Bingchao Qin1
1School of Materials Science and Engineering , Beihang University , Beijing 100191 , China.
Journal of the American Chemical Society
|September 14, 2018
概括
通过优化电子带结构和降低导热性,电 (PbTe) 中的Sn和Se合金增强了热电性能. 这种方法在773K时达到最大功率 (ZT) ~1.4.
科学领域:
- 材料科学
- 固态物理
- 热电器
背景情况:
- 高热电性能取决于平衡电气和热传输特性.
- 载体的移动性,有效质量和格子的导热性是关键的相互依赖因素.
- 电化物 (PbTe) 是一个有前途的热电材料,但其性能需要优化.
研究的目的:
- 通过与 (Sn) 和 (Se) 合金,提高PbTe的热电性能.
- 研究电子带逆向对载体传输特性的影响.
- 通过缺陷工程来降低格子的导热性.
主要方法:
- 电子带结构的计算和分析.
- 合成 Sn 和 Se 的合金 PbTe.
- 测量电传输特性 (载体移动性,功率因子).
- 测量热导电性 (晶格热导电性).
主要成果:
- 在 Sn 和 Se 合金 PbTe 中观察到电子带反向,接近拓绝缘状态.
- 通过优化有效质量和更清晰的导电带,实现了高载体移动性 (~251 cm2 V-1 s-1).
- 从0.77 Wm-1 K-1降低到0.45 Wm-1 K-1.
- 在773K时获得的最大热电功率 (ZT) 为~1.4.
结论:
- Sn和Se合金有效地优化了PbTe的热电性质.
- 电子带逆转是一种可行的策略,可以提高载波的移动性和功率因子.
- 网格的热导率降低有助于提高整体热电性能.
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