Computational design of thermoelectric alloys through optimization of transport and dopability
Computational design of thermoelectric alloys through optimization of transport and dopability
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通过优化输运和掺杂性进行热电合金的计算设计
DOI：
10.1039/d1mh01539g
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发表时间：
2022
影响因子：
13.3
通讯作者：
Gorai, Prashun
中科院分区：
文献类型：
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作者：
Qu, Jiaxing;Balvanz, Adam;Baranets, Sviatoslav;Bobev, Svilen;Gorai, Prashun
合金化是优化热电、光伏、储能等材料功能性能的常用技术。设计热电（TE）合金尤其具有挑战性，因为它是一个多性能优化问题，其中有助于高TE性能的性能是相互依存的。在这项工作中，我们开发了一个计算框架，将第一性原理计算与合金和点缺陷建模相结合，以确定优化电子、热学和缺陷性能的合金成分。我们将这一框架应用于设计n型Ba2(1−x)Sr2xCdP2 Zintl热电合金。我们对晶格参数和位序等晶体学性质的预测得到了实验的验证。为了优化导带电子结构，我们进行了能带展开来绘制合金的有效能带结构，并找到了一系列促进能带收敛和最小化合金电子散射的成分。我们通过扩展计算有序结构中点缺陷能量的标准方法来评估合金的n型可掺性。通过该框架的应用，我们确定了具有理想的电子和热输运性质以及n型可掺杂性的最佳合金成分范围。这样的计算框架也可以用于设计除TE以外的其他功能应用的合金。
Alloying is a common technique to optimize the functional properties of materials for thermoelectrics, photovoltaics, energy storage etc. Designing thermoelectric (TE) alloys is especially challenging because it is a multi-property optimization problem, where the properties that contribute to high TE performance are interdependent. In this work, we develop a computational framework that combines first-principles calculations with alloy and point defect modeling to identify alloy compositions that optimize the electronic, thermal, and defect properties. We apply this framework to design n-type Ba2(1−x)Sr2xCdP2 Zintl thermoelectric alloys. Our predictions of the crystallographic properties such as lattice parameters and site disorder are validated with experiments. To optimize the conduction band electronic structure, we perform band unfolding to sketch the effective band structures of alloys and find a range of compositions that facilitate band convergence and minimize alloy scattering of electrons. We assess the n-type dopability of the alloys by extending the standard approach for computing point defect energetics in ordered structures. Through the application of this framework, we identify an optimal alloy composition range with the desired electronic and thermal transport properties, and n-type dopability. Such a computational framework can also be used to design alloys for other functional applications beyond TE.