Given the growing demand for environmentally friendly energy sources, thermoelectric energy conversion has attracted increased interest as a promising CO₂-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⁻¹, was completely suppressed by annealing for only a few minutes and was eventually inverted to be the large negative value, − 427 μV K⁻¹. This result would further accelerate intensive studies on SnSe nanostructures, especially focusing on the realistic device structures and sealing technologies for energy harvesting applications.

鉴于对环保能源的需求不断增长，热电能量转换作为一种有希望的CO ₂吸引了越来越多的兴趣免费技术。SnSe单晶作为下一代热电材料已引起人们的关注，这是由于超低热导率产生的出色热电性能。另一方面，对于实际应用，还应关注多晶SnSe，因为生产成本和应用的灵活性是重要因素，这需要系统研究伪操作环境下热电性能的稳定性。在这里，我们报告通过大气退火极大地改变了纳米级至亚微米级的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，发现较大的正热功率+ 757μVK ^-1通过仅几分钟的退火完全抑制了α，并且最终反转为大的负值-427μVK ^-1。该结果将进一步加速对SnSe纳米结构的深入研究，尤其是将重点放在用于能量收集应用的实际设备结构和密封技术上。