Ultrathin and flexible hybrid films decorated by copper nanoparticles with a sandwich-like structure for electromagnetic interference shielding

Abstract

The emergence of electric vehicles and wearable electronics desires materials with good flexibility and high conductivity that can provide electromagnetic interference (EMI) shielding with minimal thickness. Herein, a series of flexible, light-weight, and conductive CNT/Cu hybrid films are prepared in a three-electrode configuration via a one-step electrodeposition method. The CNT/Cu hybrid films show a sandwich-like morphology with two super-thin deposited Cu layers on both sides of the CNT film and one intermediate CNT film with the Cu nanoparticles filled inside. Due to the high electrical conductivity and dominant absorption mechanism of the CNT/Cu hybrid film, the entering electromagnetic (EM) waves can be trapped and absorbed or dissipated in the form of heat within this peculiar microstructure. The CNT/Cu hybrid film exhibits an EMI shielding effectiveness (SE) value of 52 dB at a thickness of 5 µm, showing an absolute shielding effectiveness of 32 550 dB cm² g⁻¹, respectively. When more Cu particles are introduced into the CNT film, the defects of the CNT/Cu hybrid film show an upward trend and the resistance has an inverse changing tendency with the defects. In particular, the resistance of the CNT/Cu hybrid film can reach even 0.30 Ω very close to that of pure copper foil (0.29 Ω). Moreover, the CNT/Cu hybrid film also shows excellent mechanical strength (∼280 MPa). The ultrathin and flexible hybrid film with great EMI SE is a potential composite for application in electric vehicles and wearable electronics.