Structure modulation induced enhancement of microwave absorption in WS2 nanosheets.

This work reports the structural phase manipulation and the enhancement of microwave absorption in WS₂ nanosheets. Large-scale WS₂ nanosheets (1T@2H WS₂) containing mixed 2H and 1T phases were synthesized by a simple hydrothermal process. The structural characteristics and concentration (∼60%) of the 1T phase in 1T@2H WS₂ nanosheets were identified by X-ray diffraction, Raman spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. With the emergence of the 1T phase, the permittivity of 1T@2H WS₂ is more than three times higher than that of WS₂ with a pure 2H phase (2H WS₂). Moreover, the microwave absorption properties were remarkably enhanced due to the emergence of the 1T phase. Contrary to 2H WS₂, in which microwave reflection loss (R_L) is close to zero, the R_L for 1T@2H WS₂ can reach −47 dB with an effective bandwidth (<−10 dB) of 5.2 GHz. In addition, with the adjustment of the thickness of the absorber layer from 1.5 to 5 mm, 1T@2H WS₂ can achieve strong absorption in a wide band from 4 to 18 GHz. This finding provides an effective strategy for designing and synthesizing the microwave absorption materials. [ABSTRACT FROM AUTHOR]