Effect of Al doping on the microwave absorption performance of 1T/2H heterogeneous interface MoSe₂

Unique structural design and precise component adjustment are effective methods for enhancing microwave absorption performance. This study employs strategies of constructing two-dimensional nanosheet structures and modulating composition to enhance the microwave absorption efficiency of MoSe₂-based absorbing materials, aiming to comprehensively elucidate the relationships among structure, composition, dielectric properties, and impedance matching characteristics. MoSe₂ nanomaterials with mixed 1T/2H phases and Al doping levels were synthesized via a one-step hydrothermal method. The two-dimensional MoSe₂ nanosheets enhance multiple scattering and reflection, thereby increasing the transmission path of microwaves. Owing to the heterogeneous interfaces between the 1T and 2H phases, the Al-doped MoSe₂ materials exhibit strong interfacial polarization, which significantly enhances the absorption of electromagnetic wave energy. Defects at the interfaces act as polarization centers and charge accumulation sites, synergistically enhancing dipole polarization, interfacial polarization, and conductive loss, which together optimize the dielectric loss capability of the materials. When the sample filling content is 25 wt%, the AM02 sample shows the optimal performance: at a thickness of 2.43 mm and a frequency of 12.32 GHz, the minimum reflection loss (RL_min) reaches -55.68 dB. When the thickness is reduced to 2.11 mm, the effective absorption bandwidth (EAB) is 5.84 GHz (12.08-17.92 GHz), which almost covers the entire Ku band. This study provides insights into the synthesis of transition metal dichalcogenide-based doped materials and also offers new ideas for the functional optimization of other two-dimensional layered materials in the field of microwave absorption.