Construction of low-frequency and high-efficiency electromagnetic wave absorber enabled by texturing rod-like TiO₂ on few-layer of WS₂ nanosheets

As a novel 2D transition metal sulfide material, WS₂ has been proven to possess potential electromagnetic wave absorption (EMWA) property due to its peculiar electronic structure. However, the intrinsic weak impedance match and single dielectric loss domination of this material only produce high-frequency electromagnetic absorption (EMA), which is seemingly futile for the prevalent low-band 4G and 5G EMW. In this study, efforts have been made to effectively texture rod-like TiO₂ semiconductor with different mass ratios on the a few layers of WS₂ nanosheets via a simple step-by-step hydrothermal method. It is found that the WS₂/TiO₂ hybrids loaded with 10% TiO₂ at a sample thickness of 5.30 mm, the minimum RL is −43.90 dB at 5.12 GHz. When the thickness of the sample is 2.00 mm, the bandwidth with RL value less than −10 dB can reach 4.70 GHz, and the effective EMA band could be adjusted in a range of 13.84 GHz (4.16–18 GHz) by increasing the thickness from 1.0 mm to 5.5 mm. It was found that the introduction of TiO₂ nanosheets with high dielectric loss into the dielectric WS₂ nanosheets can produce a synergistic effect. The benefits of such synergestic effect include, optimization of the EMA strength and bandwidth, and a reduction of the effective EMA frequency band from high frequency to low frequency. This study paves a new avenue for the future design of low-frequency EMA materials with high efficiency.