Highly flexible and ultrathin Mo₂C film via in-situ growth on graphene oxide for electromagnetic shielding application

Molybdenum carbide (β-Mo₂C) possesses excellent electrical conductivity, good thermal and chemical stability, and is, therefore, a promising candidate material for electromagnetic (EM) shielding in diverse harsh environments. Herein, for the first time, β-Mo₂C based ultra-thin films were prepared through in-situ growth of the carbide on a self-assembled graphene oxide (GO) film. The remaining reduced GO (RGO) layers located in between two adjacent Mo₂C nanoparticles not only can work as flexible binder to impart the resultant films excellent flexibility but also enable the formation of heterogeneous nano-interface which is beneficial for the improvement of shielding by absorption. The amounts of β-Mo₂C in the resultant films were adjusted through varying the Mo precursor contents. With the introduction of β-Mo₂C phase in the resultant film, the shielding effectiveness (SE) increased significantly. At the thickness of ∼25 μm, the highest SE reaches 46.8 dB compared to 21.6 dB of the pristine RGO film. With the increase of the Mo₂C content in the resultant materials, the density increased from 0.32 to 1.23 g/cm³. The resultant Mo₂C film exhibit an SSE/t (specific SE by thickness) value of as high as 15,971 dB cm² g⁻¹.