Heterointerface engineering via controlled nitridation enables GHz-to-THz broadband electromagnetic wave absorption in Mo1.33B2Tx nanosheets

Abstract

MBene materials, as emerging two-dimensional (2D) 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 Mo_1.33B₂T_x nanosheets, we engineered a hierarchical nanoflower morphology with MoN/MoB heterointerfaces, which synergistically enhanced dielectric loss and impedance matching. The optimized Mo_1.33B₂T_x-650 absorber achieved a record minimum reflection loss (RL_min) of −61.4 dB and a broad effective absorption bandwidth across key GHz frequencies. Notably, monolayer Mo_1.33B₂T_x 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.