MXene-PEDOT:PSS Nanocomposite-Based Electromagnetic Interference Shields with Ultrahigh Absolute Shielding Effectiveness

Electromagnetic interference (EMI) poses a significant challenge in modern electronic devices, leading to malfunctions and performance degradation. Effective mitigation of EMI relies on the selection of suitable materials for EMI shielding. Two-dimensional transition metal carbide and nitride (MXene) materials have received wide attention for constructing EMI shields because of their exceptional properties. Herein, an ultrathin and lightweight Ti3C2Tx MXene nanosheet and poly(3,4-ethylenedioxythiophene)-polystyrenesulfonate (PEDOT:PSS) nanocomposite film with varying polymer contents and a unique "brick and mortar"-like layered structure was fabricated for the first time via the blade-coating technique. The Ti3C2Tx MXene and PEDOT:PSS nanocomposite film with 10 wt % polymer content exhibits superior EMI shielding effectiveness (SE) compared to the pure Ti3C2Tx film and nanocomposites with higher polymer content. The nanocomposite film of only 30.9 μm thickness displays an outstanding average SE value of 66 dB over the X-band, corresponding to 99.99997% shielding efficiency and an absolute shielding effectiveness of 44863 dB·cm2·g–1. Various factors affecting the shielding performance such as thickness, conductivity, and polymer weight percentage were studied, and the results agree well with available theoretical predictions. Furthermore, the absorptivity (A) increased substantially due to the incorporation of conductive polymers. For instance, the value of A reached from 0.16 for the Ti3C2Tx film to 0.38 for the Ti3C2Tx/PEDOT:PSS nanocomposite with a polymer content of 40 wt %. The increase in A ensures environmentally friendly green shielding. The mechanism of shielding was further studied using dielectric measurements of the nanocomposite films, which reveal high absorption loss due to interfacial and dipolar polarization in the case of a high polymer content film. This work paves the way for developing MXene and PEDOT:PSS nanocomposite-based lightweight, flexible, and ultrathin EMI shielding for ensuing commercial applications.