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) β ₁₂ -borophene ( β ₁₂ -Br) nanosheets. By leveraging the high electron mobility and low mass density of β ₁₂ -Br, we simultaneously achieve a THz EMI shield effectiveness (SE) of 70 dB and an EES _t of 4.8 × 10 ⁵ dB·cm ² /g (@0.87 THz) using a β ₁₂ -Br polymer composite. This surpasses the values of previously reported THz shielding materials with an EES _t less than 3 × 10 ⁵ dB·cm ² /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 β ₁₂ -Br nanosheets, suggesting their great potential in EMI shielding area.