纳米结构热电材料—计算的威力

来源：知社学术圈

理论计算和预测在先进高性能热电材料的发展中发挥越来越重要的贡献，并成功地引导实验理解并实现破纪录的好结果。概括地说，目前相关研究已找到了四种典型的计算策略，并增强了纳米结构体材的热电性能。但这些进展尚未得到细致梳理和综述。

来自美国西北大学的Christopher Wolverton领导的研究小组综合了最近的重要研究进展，揭示了纳米结构热电体相材料设计和发现的计算策略的规律。到目前为止，已经用高ZT > 2证明了几种体积热电材料的优异热电性能。所有这些高ZT优值的材料都优雅地体现了声子-电子晶体（PGEC）的概念。特别是，利用最小电子散射和最大限度地利用纳米结构方法的全长尺度热载流子散射的结合，实现了许多材料ZT优值的提高。纳米结构方法集成了许多调用多尺度声子散射的新思想：包括原子尺度合金化、内生纳米结构和中尺度颗粒边界控制，并以协同的方式结合了能带对齐和简并工程方法。然而，评估多尺度第二相体材系统的热电性能却仍然难以准确定量。这种综合方法也是一种将ZT提高到3的最合理方法。在追求更高的ZT优值时，第一性原理计算对于提供理论解释、材料选择甚至ZT预测都是至关重要的。

该文近期发表于npj Computational Materials 5: 58 (2019)，英文标题与摘要如下，点击左下角“阅读原文”可以自由获取论文PDF。

Computational strategies for design and discovery of nanostructured thermoelectrics

Shiqiang Hao, Vinayak P. Dravid, Mercouri G. Kanatzidis & Christopher Wolverton 

The contribution of theoretical calculations and predictions in the development of advanced high-performance thermoelectrics has been increasingly significant and has successfully guided experiments to understand as well as achieve record-breaking results. In this review, recent developments in high-performance nanostructured bulk thermoelectric materials are discussed from the viewpoint of theoretical calculations. An effective emerging strategy for boosting thermoelectric performance involves minimizing electron scattering while maximizing heat-carrying phonon scattering on many length scales. We present several important strategies and key examples that highlight the contributions of first-principles-based calculations in revealing the intricate but tractable relationships for this synergistic optimization of thermoelectric performance. The integrated optimization approach results in a fourfold design strategy for improved materials: (1) a significant reduction of the lattice thermal conductivity through multiscale hierarchical architecturing, (2) a large enhancement of the Seebeck coefficient through intramatrix electronic band convergence engineering, (3) control of the carrier mobility through band alignment between the host and second phases, and(4) design of intrinsically low-thermal-conductivity materials by maximizing vibrational anharmonicity and acoustic-mode Gruneisen parameters. These combined effects serve to enhance the power factor while reducing the lattice thermal conductivity. This review provides an improved understanding of how theory is impacting the current state of this field and helps to guide the future search for high-performance thermoelectric materials.