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

• • The optimized Mo1.33B2Tx-650 absorber achieves a minimum reflection loss (RLmin) of −61.4 dB, exceeding typical commercial microwave absorbers (RLmin > −30 dB) by a factor of two, which directly translates to >99.999% EM wave attenuation and enables stealth platforms to reduce radar cross-section by orders of magnitude. • • Monolayer Mo1.33B2Tx nanosheets deliver 94.54% THz absorption across 0.5–3.8 THz, a bandwidth that covers the entire atmospheric THz window, critical for 6G wireless communication and non-destructive testing where current absorbers fail to combine high absorption with visible transparency. • • The same monolayers exhibit 99.12% visible transparency, overcoming the opacity of conventional carbon foam and MXene absorbers (typically <20% transmittance), thereby unlocking applications in transparent electromagnetic shielding for aircraft canopies and display panels without compromising optical clarity. • • The hierarchical nanoflower morphology with MoN/MoB heterointerfaces enhances dielectric loss and impedance matching, yielding a broad effective absorption bandwidth (EAB) that spans key GHz frequencies; this structural stability, confirmed by thermal and mechanical tests, addresses the structural instability of pristine MBenes that degrade under ambient conditions.