若干典型热电材料的复杂缺陷及热电性能研究

Complex defects have close relationship with electronic structure and transport properties of thermoelectric (TE) materials. However, the defect related study is complex, and their formation mechanism and effective to transport property is unclear. It is important to TE performance breakthrough for complex defect study. Focusing on studying of complex defects and TE performance for Ga, In doped skutterudites, we have developed the defect calculation model and some results agree well with experiments. In this project, we will continually study caged skutterudites and Half-Heusler (HH) compounds and focus on the mechanism of complex defects based on the first principles, thermodynamic, and transport theory. Our goal is to obtain in-depth understanding about the formation mechanism of the complex defect and its impact on electronic structure, and reveal the relationship between TE transport properties and complex defects. Figure out the in-depth physical meaning of electron and phonon transport of these TE compounds. Identify the rules of TE performance optimization. As a result, our work will give support and guidance for materials designing and searching for novel thermoelectric material system.

复杂缺陷与热电材料电子结构，电热输运性能关系密切，但缺陷研究比较复杂，其形成机理及对输运的影响机制目前尚不清楚，其相关研究对热电材料性能突破至关重要，有望成为热电科学研究的前沿。申请者最近在Ga，In掺杂方钴矿化合物复杂缺陷及热电性能优化研究中开展了系列工作，且部分结果得到实验验证，其方法可作为新型热电材料探索与性能优化的途径。本项目以典型笼状方钴矿和Half-Heusler化合物为主要研究对象，综合利用第一性原理，热力学，及输运理论方法，深入研究这两类化合物中的复杂缺陷及形成机制，理解复杂缺陷对电子结构的影响机制，探索复杂缺陷结构－热电性能之间的关系及其规律，揭示含复杂缺陷的方钴矿和Half-Heusler化合物电子，声子输运的基本内涵，阐明存在复杂缺陷的方钴矿和HH化合物电热输运优化原则，预测可能有良好热电性能化合物及成分组成，探索与发现新型高性能热电化合物体系。

本项目以典型笼状方钴矿和Half-Heusler化合物为主要研究对象，综合利用第一性原理，热力学，及输运理论方法，深入研究这两类化合物中的复杂缺陷及形成机制，理解复杂缺陷对电子结构的影响机制，探索复杂缺陷结构－热电性能之间的关系及其规律，揭示含复杂缺陷的方钴矿和Half-Heusler化合物电子，声子输运的基本内涵，探索存在复杂缺陷的方钴矿和HH化合物电热输运优化原则，预测可能有良好热电性能化合物及成分组成，探索与发现新型高性能热电化合物体系。通过研究，发现了笼状填充方钴矿材料中填充原子引入的强弱化学键对声子输运及热导率的影响机制，揭示了负电填充元素对方钴矿材料电输运性能的影响，理解了half-Heusler中主要缺陷形态及对电子结构的影响，掌握了类金刚石热电材料缺陷问题及载流子优化问题，通过高通量计算预测一类具有高性能的新型热电材料并通过实验验证。在J. Am. Chem. Soc.，ACS Applied Materials & Interfaces, Phys. Rev. B等高质量期刊上发表SCI论文共计14篇。在项目执行期间，项目负责人及参与人并多次参加国际国内学术会议，并作报告，培养硕士生2名，在读硕士研究生1名。