Iron Oxide Quantum Dots and Graphene Nanoplatelets Integrated in a Dual-Polymer Conductive Fiber for Electromagnetic Interference-Shielding Thin Films

A facile fabrication approach has been developed to construct an integrated conductive thin film. Specifically, by integrating 1 wt % of iron oxide quantum dots (FeQDs) and 10 wt % of graphene nanoplatelets (GNPs) into a bifurcated conductive/nonconductive polymer matrix, the fabricated composite thin films achieve a nominal thickness of ∼50 μm, with a density of 1–1.2 g/cm 3, and an electrical conductivity of ∼350,000 S/m. Their shielding effectiveness reaches ∼54 dB against magnetic waves of 0–1 MHz, which is 2.5-fold higher than that of aluminum (Al) and copper (Cu) under equivalent thickness. These composites also demonstrate high shielding effectiveness within the high-frequency X-band spectrum of 8–12 GHz, with effectiveness levels reaching up to 170 dB. This capability is significantly beyond the Al and Cu range of ∼140 to 150 dB. The predominant shielding mechanisms are absorption, multireflection, reflection, hysteresis loss, and polarization loss. In summary, our work introduces QD/2D nanomaterial-integrated thin films demonstrating not only excellent capabilities within X-band frequencies but also highlighting their superior performance within the low-frequency ranges, an area where existing research is markedly sparse.