Interlayer Electrostatic Interaction Boosts Microwave Attenuation in Bi₂O₂Se Nanosheets

Layered nanosheets play a role in promoting electromagnetic attenuation in the field of microwave absorption (MA). Compared to interlayer van der Waals force, nanosheets with intrinsic electrostatic interaction are promising to optimize the microwave dissipation between layers. Bi₂O₂Se consists of alternating [Bi₂O₂]²⁺ and [Se]^2- layers coupled through intrinsic electrostatic interactions, which may provide additional polarization sites and interlayer charge-transfer pathways. However, the MA performance of these materials has not been reported yet, since their exfoliation behavior and intrinsic polarization mechanisms remain to be explored. Here, Bi₂O₂Se nanosheets were prepared by tip ultrasonication, and their MA behavior was investigated. The exfoliated Bi₂O₂Se nanosheets which show a minimum reflection loss (RL_min) of -36.99 dB at 10.86 GHz with a bandwidth of 1.7 GHz, outperforming their unexfoliated counterparts and traditional absorbers governed by van der Waals stacking. This work reveals the dielectric properties and MA performance of electrostatically stacked nanosheets, but also offers a new insight for designing highly-efficient electromagnetic compatibility regimes.