高性能低成本硒化锡热电材料研究

Thermoelectric materials have attracted ever-increasing attention in the new energy and technology field, the trend to explore new thermoelectric materials will be focused on the environmental-friendly, low-cost and earth-abundant materials. PbTe-based compounds show the outstanding performance and have been extensively studied in the thermoelectric community. To explore Pb-free and Te-free thermoelectric materials, low-cost and earth-abundant SnSe compound is selected in this study and aim at achieving high-performance over a broad temperature plateau. The Bridgeman method will be applied to grow high-quality SnSe single crystals, after that the ratio of Sn and Se will be optimized through investigating electrical transport properties. The Pb and Te substitutions on Sn and Se sites will be respectively carried out to remove the phase transition of SnSe at about 800K. To enhance the electrical transport properties over a broad temperature range, several approaches would be carried out, including optimizing carrier concentrations through doping, enhancing room temperature and high temperature effective masses and Seebeck coefficients though valence bands convergence and DOS distortion via hierarchical compositionally alloyed elements, respectively. At last, the low-cost and high-performance SnSe single crystals would be expected to achieve.

热电材料在新能源技术领域有着重要的应用，综合考虑资源和环境问题进行新型热电材料体系的研究将是未来该领域的研究趋势。PbTe基材料具有良好的热电性能而受到广泛关注，本课题基于开发不含有Pb且取代Te的新型热电材料，选定廉价和环境友好的SnSe化合物，旨在研发宽温区范围内具有高性能的热电材料。在采用布里奇曼法制备高质量SnSe单晶的基础上，研究Sn/Se最优的化学成分比，并观察Sn和Se被分别取代和同时取代后的相变点变化。重点研究通过掺杂改性优化SnSe载流子浓度，并通过元素合金化引起态密度共振和促进带结构合并分别提高室温和高温有效质量和Seebeck系数，从而提高整个温度范围内的电传输性能，最终研发出低成本且环境友好的新型高效热电材料。

热电材料在新能源技术领域有着重要的应用，综合考虑资源和环境问题进行新型热电材料体系的研究将是未来该领域的研究趋势。PbTe基材料具有良好的热电性能而受到广泛关注，本课题基于开发不含有Pb且取代Te的新型热电材料，选定廉价和环境友好的SnSe化合物，旨在研发宽温区范围内具有高性能的热电材料。在项目研究过程中，取得以下重要研究进展：基于硒化锡的多价带结构，通过调控费米能级揭示了多价带协同参与的电传输机制，大幅提高了热电转换效率；发现并利用硒化锡的层间最低热传导特性，通过电子掺杂促进离域电子杂化进而实现了层间电子隧穿，该“二维声子/三维电荷”传输特点大幅提高了热电性能；发现并利用硫化锡的多个能带随着温度的演变规律，通过引入Se优化实现了有效质量和迁移率的协同调控，在储量丰富、成本低廉、环境友好的硫化锡晶体材料中实现了高热电性能。我们的研究结果表明SnSe是一种低成本且环境友好的新型高效热电材料。在此项目的支持下，我们发表了SCI论文43篇，其中Science 3篇。授权1项美国专利，1项国家专利,申请发明专利3项。

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