Bi2Te3/Sb2Te3纳米薄膜和超晶格热电性能提升的理论研究

纳米化和低维化可以有效地提高材料的热电性能，这给我们提供了一种新的寻找高性能热电材料的途径。本项目拟采用密度泛函(微扰)理论、非平衡态格林函数和玻尔兹曼输运理论，理论上设计目前室温下热电性能最好的材料Bi2Te3 和Sb2Te3 (001)和(111)为表面的薄膜与Bi2Te3/Sb2Te3 纳米超晶格，研究其电子结构、声子能谱、及热电性能等性质，揭示Bi2Te3 和Sb2Te3 薄膜的热电性能随着薄片厚度的变化规律，及Bi2Te3/Sb2Te3纳米超晶格电子特性和热电性能随迭代周期演化的规律，进而对薄膜与纳米超晶格掺杂，优化其载流子浓度，提高热电性能，获得高性能薄膜和纳米超晶格热电材料。建立纳米热电材料的理论模型，探索该类热电材料的微观结构和热电性起源，寻求提高其热电性的有效途径。本课题对发展高性能的Bi2Te3 系热电材料、推动纳米热电材料的应用具有重要的学术意义和应用

Nano- and low-dimensional can effectively improve the thermoelectric properties of the material，which provides us with a new way of looking for high performance thermoelectric materials.The project based the method of the density functional (perturbation) theory, non-equilibrium Green's function and Boltzmann transport theory theoretically design thin film of (001) and (111) surface and nano superlattice of the best thermoelectric materials Bi2Te3 and Sb2Te3 of room temperature. The variation of thermoelectric properties of the Bi2Te3 and Sb2Te3 (001) thin film with the change of the thickness of the sheet layer and the laws of evolution of the crystal structure, electronic structure and thermoelectric properties of Bi2Te3/Sb2Te3 nano superlattice with the iteration cycle will be revealed, and the thin film and nano superlattice will be doped. Their carrier concentrationwill be optimized and the thermoelectric properties will be improved. The high-performance thin-film and nano Superlattice thermoelectric materials will be obtained. Theoretical model of nano thermoelectric materials will be constructed. The microstructure and thermoelectric origin of these thermoelectric materials will be explored. An effective way to improve the thermoelectric properties will be sought. The model of the thermoelectric nano superlattice will be constructed. The research of this subject has important academic significance and value for the developing the thermoelectric materials of the high-performance Bi2Te3 series and promoting the application of nano thermoelectric materials.