Dou Wei, Gong Yaru, Huang Xinqi, Li Yanan, Zhang Qingtang, Liu Yuqi, Xia QinXuan, Jian Qingyang, Xiang Deshang, Li Di, Zhang Dewei, Zhang Shihua, Ying Pan, Tang Guodong
National Key Laboratory of Advanced Casting Technologies, MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials Technology, Engineering Research Center of Materials Behavior and Design, Ministry of Education, Nanjing University of Science and Technology, Nanjing, 210094, China.
Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei, 230031, China.
Small. 2024 Jul;20(28):e2311153. doi: 10.1002/smll.202311153. Epub 2024 Feb 2.
Here, a high peak ZT of ≈2.0 is reported in solution-processed polycrystalline Ge and Cd codoped SnSe. Microstructural characterization reveals that CdSe quantum dots are successfully introduced by solution process method. Ultraviolet photoelectron spectroscopy evinces that CdSe quantum dots enhance the density of states in the electronic structure of SnSe, which leads to a large Seebeck coefficient. It is found that Ge and Cd codoping simultaneously optimizes carrier concentration and improves electrical conductivity. The enhanced Seebeck coefficient and optimization of carrier concentration lead to marked increase in power factor. CdSe quantum dots combined with strong lattice strain give rise to strong phonon scattering, leading to an ultralow lattice thermal conductivity. Consequently, high thermoelectric performance is realized in solution-processed polycrystalline SnSe by designing quantum dot structures and introducing lattice strain. This work provides a new route for designing prospective thermoelectric materials by microstructural manipulation in solution chemistry.
在此，报道了溶液处理的多晶锗和镉共掺杂硒化锡中约2.0的高峰值ZT。微观结构表征表明，通过溶液法成功引入了CdSe量子点。紫外光电子能谱表明，CdSe量子点提高了SnSe电子结构中的态密度，这导致了较大的塞贝克系数。研究发现，锗和镉共掺杂同时优化了载流子浓度并提高了电导率。增强的塞贝克系数和载流子浓度的优化导致功率因数显著增加。CdSe量子点与强烈的晶格应变相结合，产生强烈的声子散射，导致超低的晶格热导率。因此，通过设计量子点结构和引入晶格应变，在溶液处理的多晶SnSe中实现了高热电性能。这项工作为通过溶液化学中的微观结构操纵设计潜在的热电材料提供了一条新途径。
