能带与共格纳米析出相协同调控SnSe多晶热电性能研究

SnSe多晶具有制备工艺简单，生产成本低，机械性能稳定等突出优点，具有广阔应用前景。然而受限于低功率因子和高热导率，其热电性能相对较低。项目提出利用能带和共格纳米析出相协同调控SnSe热电性能新思路，通过能带收敛、态密度提升等能带调控手段，显著提高材料的功率因子；进一步利用共格纳米析出相调控SnSe多晶热电性能，由于其对载流子迁移率和功率因子的抑制作用很小，对声子散射的弛豫时间极短，该方法既能保持材料高功率因子，又可以有效抑制晶格热导率，实现对材料电声输运的协同调控，优化热电性能。系统研究能带收敛、态密度提升引起SnSe热电性能的变化机制；共格纳米析出相对SnSe多晶显微结构的影响；能带与共格纳米析出相对材料电声输运的协同调控机制。揭示能带调控对材料热电性能的影响机制，探明能带与共格纳米析出相对SnSe多晶电声输运的协同调控机制。通过本项目的研究为高性能热电材料研发提供新思路和理论基础。

Polycrystalline SnSe has great potential for thermoelectric applications due to its simple manufacturing technology, low preparation cost and stable mechanical properties. Low power factor and high thermal conductivity lead to relatively low thermoelectric performance in polycrystalline SnSe. In this project, tailoring band structure and endotaxial nanostructuring are proposed to synergistically optimizing thermoelectric performance of polycrystalline SnSe. Band convergence and enhanced density of state are suggested to improve the power factor. We further modulate the electrical and thermal transport properties in polycrystalline SnSe by endotaxial nanostructuring. Endotaxial nanoprecipitates don’t suppress carrier scattering and power factor. The phonon scattering relaxation time of the endotaxial nanoprecipitates is much more shorter than the other phonon scattering process. This method not only helps maintain high power factor but also significantly diminishes lattice thermal conductivity. The electrical and thermal transport properties of polycrystalline SnSe can be synergistically optimized. The regulation mechanism of band convergence and enhanced density of state on thermoelectric properties of materials will be systematically studied. The effects of endotaxial nanoprecipitates on microstructures of polycrystalline will be investigated. The synergistic modulating mechanism of tailoring band structure and endotaxial nanostructuring will be studied. We can reveal the effect of tailoring band structure on thermoelectric properties and the synergistic modulating mechanism of tailoring band structure and endotaxial nanostructuring by this project. This project will provide a new pathway and theoretical foundation for research and development of high performance thermoelectric material.