Heterointerface engineering via controlled nitridation enables GHz-to-THz broadband electromagnetic wave absorption in Mo1.33B2Tx nanosheets
MBene materials, as emerging two-dimensional transition metal borides, exhibit exceptional potential for electromagnetic (EM) wave absorption due to their high conductivity and tunable surface properties. However, their structural instability and limited EM absorption efficiency in the gigahertz (GHz) or terahertz (THz) band remain critical challenges. Controlled nitridation enables the construction of heterogeneous interfaces, providing an effective strategy for precisely tailoring EM absorption properties. Herein, through NH3 annealing of exfoliated Mo1.33B2Tx nanosheets, we engineered a hierarchical nanoflower morphology with MoN/MoB heterointerfaces, which synergistically enhanced dielectric loss and impedance matching. The optimized Mo1.33B2Tx-650 absorber achieved a record minimum reflection loss (RLmin) of −61.4 dB and a broad effective absorption bandwidth across key GHz frequencies. Notably, monolayer Mo1.33B2Tx nanosheets simultaneously exhibited ultrahigh THz wave absorption (94.54% at 0.5–3.8 THz) and near-perfect visible transparency (99.12%), unlocking unprecedented potential for transparent optoelectronic devices. Combined with superior thermal and mechanical properties, this study establishes a generalizable paradigm for designing multifunctional MBene-based absorbers operating across GHz to THz spectra.