Cu₂NiSnS₄ Nanoparticles Supported on rGO for Dual Frequency Range Electromagnetic Shielding

The development of advanced electromagnetic wave absorbing materials capable of simultaneous dual/multiple frequency bands has received widespread attention due to their potential to mitigate electromagnetic interference and enhance communication technologies. Herein, we report efficient dual frequency band electromagnetic wave (EMW) absorption from a hybrid of high-purity Cu₂NiSnS₄ (CNTS) nanoparticles and reduced graphene oxide (rGO) (CNTS/rGO). The surface morphology and physicochemical properties of prepared materials (pure CNTS and CNTS/rGO with different rGO filling ratios) were characterized using powder X-ray diffraction (PXRD), Raman spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and scanning TEM (STEM) analysis. The electromagnetic-wave-absorption performances were conducted using a vector network analyzer with the frequency ranging between 2 and 18 GHz. The complex permittivity, magnetic permeability, dielectric loss tangent, magnetic loss tangent, dielectric relaxation phenomena (Cole–Cole plot), eddy current loss parameter, and attenuation constant values related to the electromagnetic wave absorption of the materials have been studied. The experimental results confirmed that CNTS and CNTS/rGO composite materials can absorb different electromagnetic wave frequency bands. Significantly, CNTS/rGO (50%) exhibits exceptional electromagnetic-wave-absorption properties across dual frequency bands with the optimal absorption loss of −38.2 dB at 17.1 GHz and a broad absorption peak of −10.4 dB at 5.6 GHz, offering significant potential for use in various technological applications, including stealth technology, wireless communication, and radar systems. The enhanced microwave-absorption properties of the material can be attributed to the successful design of a well-dispersed heterostructure of CNTS/rGO containing different phases, including a hybrid of dielectric and magnetic material along with the efficient dielectric loss, magnetic loss, and their synergistic contribution in the electromagnetic wave absorption. The outcomes of this research can lead to technological advancements, improved functionality, and future direction to pressing challenges in today’s interconnected world.