Tang Jun, Xu Rui, Zhang Jian, Li Di, Zhou Weiping, Li Xiaotong, Wang Zhihe, Xu Feng, Tang Guodong, Chen Guang
Key Laboratory of Materials Physics, Institute of Solid State Physics , Chinese Academy of Sciences , Hefei 230031 , China.
National Laboratory of Solid State Microstructures, Department of Physics , Nanjing University , Nanjing 210093 , China.
ACS Appl Mater Interfaces. 2019 May 1;11(17):15543-15551. doi: 10.1021/acsami.9b00958. Epub 2019 Apr 19.
The Seebeck coefficient and carrier mobility in reported doped BiCuSeO system are too small, which limits the improvement of thermoelectric performance. Here, we proposed a novel strategy for optimizing thermoelectric performance by increasing Seebeck coefficient and boosting carrier mobility. We demonstrate that light element Li doping boosts carrier mobility (7.39 cm V s) due to largely reduced carrier scattering, which results in about 2-fold increase in carrier mobility as compared with reported BiBaCuSeO through modulation doping or microstructure texturing. Moreover, the Seebeck coefficient remarkably increases by contribution of spin entropy induced by magnetic ions Mn incorporation. The enhancement of Seebeck coefficient coupled with enhanced electrical conductivity result in high power factor. Furthermore, nanoprecipitates and dual-atom point defect leads to a significant reduction of lattice thermal conductivity. Therefore, a high ZT value of 0.9 was achieved at 873 K through optimizing power factor while maintaining low thermal conductivity. Our findings provide a new perspective for designing prospective thermoelectric materials.
在已报道的掺杂BiCuSeO体系中，塞贝克系数和载流子迁移率过小，这限制了热电性能的提升。在此，我们提出了一种通过提高塞贝克系数和增强载流子迁移率来优化热电性能的新策略。我们证明，轻元素Li掺杂由于大大减少了载流子散射，从而提高了载流子迁移率（7.39 cm² V⁻¹ s⁻¹），与通过调制掺杂或微观结构织构化的已报道BiBaCuSeO相比，载流子迁移率提高了约2倍。此外，由于掺入磁性离子Mn诱导的自旋熵的贡献，塞贝克系数显著增加。塞贝克系数的增强与电导率的提高相结合，导致了高功率因子。此外，纳米沉淀和双原子点缺陷导致晶格热导率显著降低。因此，通过优化功率因子同时保持低热导率，在873 K时实现了0.9的高ZT值。我们的研究结果为设计有前景的热电材料提供了新的视角。
