Shimizu Sunao, Miwa Kazumoto, Kobayashi Takeshi, Tazawa Yujiro, Ono Shimpei
Materials Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI), Yokosuka, Kanagawa, 240-0196, Japan.
Electric Power Engineering Systems, Yokosuka, Kanagawa, 240-0101, Japan.
Sci Rep. 2021 Jan 15;11(1):1637. doi: 10.1038/s41598-021-81195-7.
Given the growing demand for environmentally friendly energy sources, thermoelectric energy conversion has attracted increased interest as a promising CO-free technology. SnSe single crystals have attracted attention as a next generation thermoelectric material due to outstanding thermoelectric properties arising from ultralow thermal conductivity. For practical applications, on the other hand, polycrystalline SnSe should be also focused because the production cost and the flexibility for applications are important factors, which requires the systematic investigation of the stability of thermoelectric performance under a pseudo operating environment. Here, we report that the physical properties of SnSe crystals with nano to submicron scale are drastically modified by atmospheric annealing. We measured the Seebeck effect while changing the annealing time and found that the large positive thermopower, + 757 μV K, was completely suppressed by annealing for only a few minutes and was eventually inverted to be the large negative value, - 427 μV K. This result would further accelerate intensive studies on SnSe nanostructures, especially focusing on the realistic device structures and sealing technologies for energy harvesting applications.
鉴于对环境友好型能源的需求不断增长，热电能量转换作为一种有前景的无碳技术已引起越来越多的关注。由于超低热导率所产生的优异热电性能，SnSe单晶作为下一代热电材料受到了关注。另一方面，对于实际应用而言，多晶SnSe也应受到关注，因为生产成本和应用灵活性是重要因素，这就需要在模拟运行环境下系统地研究热电性能的稳定性。在此，我们报道了通过大气退火可显著改变纳米至亚微米尺度的SnSe晶体的物理性质。我们在改变退火时间的同时测量了塞贝克效应，发现仅退火几分钟就能完全抑制高达 +757 μV K 的大正热功率，最终热功率反转成为 -427 μV K 的大负值。这一结果将进一步加速对SnSe纳米结构的深入研究，特别是关注用于能量收集应用的实际器件结构和密封技术。
