先进半导体热电材料微观机理的第一性原理研究及性能优化和设计

项目名称： 先进半导体热电材料微观机理的第一性原理研究及性能优化和设计

项目编号： No.11474273

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 邓惠雄

作者单位： 中国科学院半导体研究所

项目金额： 90万元

中文摘要： 半导体热电材料是一种能够实现热电相互转化功能型材料。它可以利用自然界的温差、工业废热、放射性同位素衰变及燃料燃烧所产生的热等进行发电，在新能源开发、汽车节能、环境保护、太空探索及军事等领域有着广阔的应用前景。目前限制热电材料发展最主要问题是其效率太低成本太高，寻找高效率低成本的热电化合物成为了近年来热电材料研究的核心问题。本项目将从第一性原理出发，同时计算电子输运和晶格热导，发展一套完整准确计算热电优值ZT的理论模拟方法。在此基础上计算各种具体半导体热电材料，包括Zintl相化合物、新型Half-Heusler化合物、铜硫系化合物Cu2-xY(Y=S、Se 或Te)等，探讨热电性能各向异性，揭示其微观物理机制，并讨论不同调控机制（掺杂、合金及纳米结构等）对热电性能的影响，提出具体合理的优化途径，指导实验。探索和预测新型的热电材料，力图实现从热电材料的性能要求到设计出材料构型的反向设计方案。

中文关键词： 半导体热电材料；电子结构；晶格热导；第一性原理计算

英文摘要： Thermoelectric materials can directly convert heat, which can be from the combustion of fossil fuels, from industrial waste heat, or as a byproduct of various processes (e.g. combustion, chemical reactions, and nuclear decay), to electricity by using a temperature difference to induce charge carrier to flow in a semiconductor. It, therefore, has broad application prospects in clean energy development, environmental protection, automobile conservation technology, space exploration, military, and so on. At present, the big challenging task to enable the widespread use of thermoelectric devices is how to highly improve its maximum thermal-to-electricity conversion efficiency and simultaneously reduce the cost. In this project, we will develop a method for calculating the Figure of merit ZT from ab initio Density Functional Theory (DFT) with a combination of electronic transport properties and lattice thermal conductivity contributions, as well as considering the anisotropic properties of thermoelectric performance. Through applying this method to calculate some specific promising semiconductor thermoelectric material, such as, Zintl phase compounds, Half-Heusler compounds, Copper chalcogenides Cu2-xY(Y=S, Se or Te)， and so on, we will understand the atomic mechanism of thermoelectric phenomenon, and discuss the effects on thermoelectric performance of various manipulating approaches (e.g. doping, alloying and nanostructures, and so on). Finally, with this understanding, we will present the reasonable and feasible strategies in the view of both band structure and microstructure engineering for optimization of performance of existing thermoelectric materials, and simultaneously make attempts to predict and inversely design new advanced thermoelectric materials with high ZT value.

英文关键词： thermoelectric semiconductors;electronic structures;lattice thermal conductivity;first principle calculations