Efficient microwave absorber for phase-engineered modulation of MoS2 induced by trace atom doping

Abstract

The traditional electromagnetic microwave (EM) absorption materials are limited by the electromagnetic response characteristics dominated by a single loss mechanism, and it is difficult to realize the cooperative optimization of multiple loss mechanisms and impedance matching. In this study, the phase structure engineering and defect characteristics of MoS₂ were controlled by heteroatom doping strategy, and Fe-doped yolk-shell MoS₂ nanoflower microspheres EM absorption material were successfully prepared. The introduction of Fe atoms can form an atomic-level " charge-enriched center " defect, induce crystal structure distortion, and thus realize the construction of a high-density and stable 1T/2H heterogeneous interface. The ratio of 1T/2H phase increases with the increase of the gradient of Fe atom doping. Specifically, the 8Fe-MoS₂ sample demonstrated excellent EM absorption performance at a matching thickness of 1.95 mm, with a maximum effective absorption bandwidth (EAB) of 5.36 GHz and a minimum reflection loss (RL) of −72.18 dB (1.65 mm). Through detailed characterization and multi-scale simulation, it is revealed that the superior EM absorption performance is the result of the synergistic effect of Fe defect induced polarization, interface polarization at high density heterogeneous interface, resistance loss and EM transmission path optimization. This multi-scale control strategy precisely combines the coupling effect of MoS₂'s defect characteristics and phase structure with multiple dielectric loss mechanisms, which provides a new design idea for developing high-performance MoS₂-based EM absorption materials.