Bi-semiconductor heterojunction Cu9S5@VO2 microspheres with morphology regulation as broadband high-performance electromagnetic wave absorber

The development of heterojunction composite materials with excellent electromagnetic wave absorption performance is emerging as an effective means to address the hazardous electromagnetic waves. Here, two types of Cu9S5@VO2 microspheres with different morphologies were designed. The Cu9S5@VO2 microspheres were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and vector network analyzer. Results show that the minimum reflection loss (RLmin) of unique lamellar-flower Cu9S5@VO2 sphere reaches 56.98 dB, and the wide effective absorption bandwidth (EAB) is 6.88 GHz at only 2.5 mm thickness due to the synergistic effect of multiple loss mechanisms. Radar simulated radar cross section (RCS) results show a reduction of 16.56 dBm(2). The design engineering of the phase interface on the material surface can functionalize the material surface properties, introduce lattice defects and polarization behavior, and improve the microwave absorption performance of the material. This work enriches the use of copper sulfide-based functional composites in microwave absorption with high-performance microwave absorbers by designing microscopically controllable, simple processes and heterojunction design.