Harmonizing material quantity and terahertz wave interference shielding efficiency with metallic borophene nanosheets

Materials with electromagnetic interference (EMI) shielding in the terahertz (THz) regime, while minimizing the quantity used, are highly demanded for future information communication, healthcare, and mineral resource exploration applications. Currently, there is often a trade-off between the amount of material used and the absolute EMI shielding effectiveness (EES_t) for the EMI shielding materials. Here, we address this trade-off by harnessing the unique properties of two-dimensional (2D) β₁₂-borophene (β₁₂-Br) nanosheets. By leveraging the high electron mobility and low mass density of β₁₂-Br, we simultaneously achieve a THz EMI shield effectiveness (SE) of 70 dB and an EES_t of 4.8 × 10⁵dB·cm²/g (@0.87 THz) using a β₁₂-Br polymer composite. This surpasses the values of previously reported THz shielding materials with an EES_t less than 3 × 10⁵dB·cm²/g and a SE smaller than 60 dB, while only needs 0.1 wt.% of these materials to realize the same SE value. Furthermore, by capitalizing on the superior mechanical properties of the composite, with 158% tensile strain at a Young's modulus of 21 MPa, we demonstrate the high-efficiency shielding performances of conformably coated surfaces based on β₁₂-Br nanosheets, suggesting their great potential in EMI shielding area.