Electromagnetic interference shielding properties of hierarchical core-shell palladium-doped MoS2/CNT nanohybrid materials

Abstract

A simple hydrothermal method was used to prepare palladium-doped few-layer molybdenum disulfide nanosheets grown on the surface of a multi-walled carbon nanotube (Pd–MoS2/CNT) with forming a three-dimensional (3D) hierarchical core-shell heterostructure. This paper provides first-hand information on electromagnetic interference (EMI) scattering and electromagnetic (EM) parameters in the X-band (8–12 GHz) microwave frequency range. In this hierarchical core-shell heterostructure, SEM and TEM photos clearly show that CNT forms the core, while Pd-doped few layers MoS2 grown on the surface of CNT is the shell. The Pd-doped MoS2/CNT nanohybrids can greatly improve electrical conductivity, defect dipole polarization, interfacial polarization, dielectric relaxation loss, and mobile charge carriers between core and shell. These are the reason for the substantial enrichment in EMI shielding effectiveness (SE) and dielectric performance. The 10% Pd–MoS2/CNT nanohybrid has a higher EMI SE and dielectric loss tangent (SET ~ 26.50 dB, tanδε ~2.37) than the 5% Pd–MoS2/CNT (SET ~ 22.50 dB, tanδε ~1.90) and undoped MoS2/CNT (SET ~ 21.55 dB, tanδε ~0.92) at the same thickness of 1 mm. The strong EMI SE and dielectric loss tangent are found due to their higher dipole polarization, conduction, and relaxation losses. The doping concentration of Pd-atoms has a significant impact on EM parameters (ε′, ε″, μ′ & μ″) and EMI scattering parameters (S11, S21, S12 & S22). The experimental results indicated that the 10% Pd–MoS2/CNT nanohybrid might be considered a good EMI shielding and dielectric material for large scale use in intelligence wireless information and communication devices in the future.