2D nanosheets and composites for EMI shielding analysis

Abstract

Liquid exfoliated, 2-dimensional (2D), few layered graphene and molybdenum disulfide nanosheets (GNS and MNS) are size selected for EMI shielding application. Scanning electron microscopy (SEM) has confirmed the lateral dimensions increase (1–2 µm for GNS and MNS) with lowering centrifugation speed (1000 to 500 rpm). The micron size (~ 15 µm) restacked structures of GNS and MNS (L ~ 2 µm) over a nylon membrane have shown ~ 16 dB and ~ 6 dB EMI shielding effectiveness (1–8 GHz frequency), respectively. The enhanced EMI shielding effectiveness for GNS-500 may be credited to its high carrier mobility as well as high aspect ratio of nanosheets. The GNS-500 are further dispersed (0.3 wt.%) in thermoplastic polyurethane for their applicability as flexible EMI shielding material. The dielectric characteristics predicted an enhancement for the attenuation (200 MHz–1 GHz). The experimental results (1–8 GHz) suggested the maximum attenuation ~ 18 dB showing the composite applicability as a broadband EMI shielding material.

Ultrasonication Influence on the Morphological Characteristics of Graphene Nanoplatelet Nanocomposites and Their Electrical and Electromagnetic Interference Shielding Behavior

“…These losses increase not only with the GNP content but also with the surface area, as it has been recently reported [ 31 ]. A higher aspect ratio raises the percolation network (in this case, the larger the specific area, the higher the aspect ratio), which means that it has a higher electrical conductivity and thus increases the EMI shielding effectiveness [ 57 ]. It is important to note that this increase in shielding due to the increase in the electrical conductivity by the introduction of carbonaceous reinforcements can be preferably caused by reflection; however, the most desirable is to generate an adequate impedance mismatch to avoid these losses due to reflection and to increase the absorption losses, for example, by adding ferrites [ 13 ].…”

Design of Multilayered 2D Nanomaterial Composite Structures for EMI Shielding Analysis

“…Khan et al. 34 found an EMI effectiveness of 18 dB with graphene- and MoS 2 -based materials. The EMI shielding of the MoS 2 -rGO/Fe 3 O 4 nanostructure was assessed in the 8–12 GHz range by Prasad et al 35 and was 8.27 dB.…”

“…For example, Zhang et al 33 reported sulfonated reduced less defect graphene oxide (S-rLGO) combined with P(St-BA) latex through blending and casting processes and reported an overall shielding effectiveness of 16 dB. Khan et al 34 found an EMI effectiveness of 18 dB with graphene-and MoS 2 -based materials. The EMI shielding of the MoS 2 -rGO/Fe 3 O 4 nanostructure was assessed in the 8−12 GHz range by Prasad et al 35 and was 8.27 dB.…”

2D Transition Metal Dichalcogenides‐Based Composites for Electromagnetic Interference Shielding and Microwave Absorption Applications

“…Khan et al [ 107 ] reported that they used the liquid‐phase exfoliation method to reduce the bulk of MoS 2 to 2D NSs. They were able to make the lateral dimensions of the NSs bigger by lowering the centrifugation speed from 1000 to 500 rpm.…”