Key Laboratory of Multi-Scale Manufacturing Technology, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, People's Republic of China.
Nanotechnology. 2018 Jan 12;29(2):025705. doi: 10.1088/1361-6528/aa9bfe.
Two-dimensional materials have gained great attention as a promising thermoelectric (TE) material due to their unique density of state with confined electrons and holes. Here, we synthesized 1T phase tungsten disulfide (WS) nanosheets with high TE performance via the hydrothermal method. Flexible WS nanosheets restacked thin films were fabricated by employing the vacuum filtration technique. The measured electrical conductivity was 45 S cm with a Seebeck coefficient of +30 μV K at room temperature, indicating a p-type characteristic. Furthermore, the TE performance could be further improved by thermal annealing treatment. It was found the electrical conductivity could be enhanced 2.7 times without sacrificing the Seebeck coefficient, resulting in the power factor of 9.40 μW m K. Moreover, such 1T phase WS nanosheets possess high phase stability since the TE properties maintained constant at least half one year in the air atmosphere. Notably, other kinds of 1T phase transitional metal dichalcogenides (TMDCs) with excellent TE performance also could be imitated by using the procedure in this work. Finally, we believe a variety of materials based on 1T phase TMDCs nanosheets have great potential as candidate for future TE applications.
二维材料因其具有限制电子和空穴的独特态密度而备受关注，有望成为一种有前途的热电（TE）材料。在这里，我们通过水热法合成了具有高 TE 性能的 1T 相二硫化钨（WS）纳米片。通过真空过滤技术制备了柔性 WS 纳米片再堆积薄膜。在室温下，测量的电导率为 45 S cm，塞贝克系数为+30 μV K，表明为 p 型特性。此外，通过热退火处理可以进一步提高 TE 性能。研究发现，电导率可以提高 2.7 倍，而塞贝克系数不受影响，从而功率因子达到 9.40 μW m K。此外，这种 1T 相 WS 纳米片具有高的相稳定性，因为在空气气氛中，TE 性能至少在半年内保持稳定。值得注意的是，其他具有优异 TE 性能的 1T 相过渡金属二卤化物（TMDCs）也可以通过本工作中的程序进行模拟。最后，我们相信基于 1T 相 TMDCs 纳米片的各种材料具有作为未来 TE 应用候选材料的巨大潜力。
