School of Material Science and Engineering, Beijing Institute of Technology, Beijing 100081, China.
Nanoscale. 2015 Oct 14;7(38):15734-40. doi: 10.1039/c5nr04670j. Epub 2015 Sep 9.
In this study, few-layered MoS2 nanosheets (MoS2-NS) were obtained via the top-down exfoliation method from bulk MoS2 (MoS2-Bulk), and the dielectric properties and microwave absorption performance of MoS2-NS were first reported. The dimension-dependent dielectric properties and microwave absorption performance of MoS2 were investigated by presenting a comparative study between MoS2-NS and MoS2-Bulk. Our results show that the imaginary permittivity (ε'') of MoS2-NS/wax is twice as large as that of MoS2-Bulk/wax. The minimum reflection loss (RL) value of MoS2-NS/wax with 60 wt% loading is -38.42 dB at a thickness of 2.4 mm, which is almost 4 times higher than that of MoS2-Bulk/wax, and the corresponding bandwidth with effective attenuation (<-10 dB) of MoS2-NS/wax is up to 4.1 GHz (9.6-13.76 GHz). The microwave absorption performance of MoS2-NS is comparable to those reported in carbon-related nanomaterials. The enhanced microwave absorption performance of MoS2-NS is attributed to the defect dipole polarization arising from Mo and S vacancies and its higher specific surface area. These results suggest that MoS2-NS is a promising candidate material not only in fundamental studies but also in practical microwave applications.
在这项研究中,通过自上而下的剥离方法从块状 MoS2(MoS2-Bulk)中获得了少层 MoS2 纳米片(MoS2-NS),并首次报道了 MoS2-NS 的介电性能和微波吸收性能。通过对 MoS2-NS 和 MoS2-Bulk 进行比较研究,研究了 MoS2 的尺寸依赖性介电性能和微波吸收性能。结果表明,MoS2-NS/wax 的虚介电常数(ε'')是 MoS2-Bulk/wax 的两倍。当负载量为 60wt%时,MoS2-NS/wax 的最小反射损耗(RL)值为-38.42dB,厚度为 2.4mm,几乎是 MoS2-Bulk/wax 的 4 倍,MoS2-NS/wax 的有效衰减(< -10dB)带宽高达 4.1GHz(9.6-13.76GHz)。MoS2-NS 的微波吸收性能可与碳相关纳米材料的报道相媲美。MoS2-NS 增强的微波吸收性能归因于 Mo 和 S 空位引起的缺陷偶极子极化及其更高的比表面积。这些结果表明,MoS2-NS 不仅在基础研究中,而且在实际的微波应用中都是一种很有前途的候选材料。