Polymorphic Transformation and Dislocation Regulation in MoS2 Enabled by Electric Field Postprocessing for Enhanced Electromagnetic Wave Absorption

Electric field modulation offers a non-contact route to tune electromagnetic wave absorption (EWA) by controlling carrier behavior. However, current in-situ electric field modulation strategies are often hindered by multi-physics factors during synthesis, limiting a deeper understanding of the decoupled mechanism of the electric field. Here, we report a postprocessing strategy that employs direct current electric field to induce d-orbital electron migration, triggering the 2H to 1T-phase transition in MoS2, accompanied by dislocation generation. On one hand, the increased 1T-phase content optimizes the conductive loss. Meanwhile, the Fermi level mismatch at 2H/1T interfaces creates electron accumulation regions that drive polarization loss. On the other hand, positive and negative charges accumulate on opposite sides of the dislocation lines, forming ordered equivalent dipole arrays, markedly boosting polarization. After treatment at 6 V for 10 min, MoS2 achieves an effective absorption bandwidth of 6.72 GHz at 2.20 mm, a 440% enhancement relative to the untreated sample. This improvement exceeds the typical 150% to 350% enhancement achieved by most field modulation strategies. This work demonstrates that the electric field postprocessing strategy effectively tailors the phase ratio, defects, and EWA performance of MoS2, offering a pathway for the design of advanced electromagnetic wave absorbers.