Center for Semiconductor and Nanotechnology Center (CCS Nano), University of Campinas, Sao Paulo, Brazil. School of Physical Sciences, Jawaharlal Nehru University, New Delhi, India.
Nanotechnology. 2019 Dec 13;30(50):505704. doi: 10.1088/1361-6528/ab4290. Epub 2019 Sep 9.
The present work reports nanocomposite of CdSe/VO core-shell quantum dots with reduced graphene oxide (rGO-V-CdSe), as an efficient lightweight electromagnetic wave shielding material, synthesized by a simplistic solvothermal approach. The as-synthesized nanocomposite was analyzed for its structural, compositional and morphological features by x-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy and x-ray photoelectron spectroscopy (XPS). The measurement of complex permittivity/permeability and total shielding efficiency of the as-synthesized samples has been done in a wide frequency range of 8-12 GHz (X-band). Compared to rGO and rGO-CdSe, rGO-V-CdSe nanocomposite exhibits significantly enhanced EMI shielding properties in terms of both dielectric loss and total shielding SE . The high value of real permittivity (average ε'∼70) and the overall shielding effectiveness up to ∼38 dB have been recorded for rGO-V-CdSe nanocomposite. The studies also infer that the absorption contributes more in total shielding than reflection. The high value of dielectric loss and shielding effectiveness could also be attributed to the presence of various defects leading to dipolar and interfacial polarizations. The excellent EMI shielding properties of the nanocomposite in GHz frequency range (X-band) pave an intuitive way for fabricating a versatile EMI shielding nanocomposite material for applications.
本工作报道了通过简便的溶剂热法合成的 CdSe/VO 核壳量子点与还原氧化石墨烯（rGO-V-CdSe）的纳米复合材料，作为一种高效的轻质电磁波屏蔽材料。通过 X 射线衍射（XRD）、透射电子显微镜（TEM）、拉曼光谱和 X 射线光电子能谱（XPS）对合成的纳米复合材料进行了结构、组成和形态特征分析。在 8-12GHz（X 波段）的宽频率范围内对合成样品的复介电常数/磁导率和总屏蔽效率进行了测量。与 rGO 和 rGO-CdSe 相比，rGO-V-CdSe 纳米复合材料在介电损耗和总屏蔽 SE 方面表现出显著增强的 EMI 屏蔽性能。rGO-V-CdSe 纳米复合材料的实部介电常数（平均 ε'∼70）和总屏蔽效能高达 ∼38dB。研究还推断，吸收对总屏蔽的贡献大于反射。高介电损耗和屏蔽效率也可归因于存在各种缺陷，导致偶极和界面极化。该纳米复合材料在 GHz 频率范围内（X 波段）具有优异的 EMI 屏蔽性能，为制备多功能 EMI 屏蔽纳米复合材料开辟了一条直观的途径，可应用于 EMI 屏蔽。
