Construction of hollow copper selenide boxes and S-doping for enhanced electromagnetic wave absorption

With the proliferation of the use of wireless communication technologies, lightweight, easily fabricated electromagnetic wave (EMW) absorbers are in great demand for commercial and stealth applications. In this paper, well-defined Cu2O microcubes were successfully converted into S-doped Cu2_ xSe micro-cubic boxes at room temperature by a template-directed in situ selenization/sulfidation reaction. The Cu2_xSe boxes were obtained under the combined effect of Kirkendall effect and Ostwald ripening, and the composite products with paraffins exhibited good EMW low-frequency absorption properties at 40 wt%, with RL(min) exceeding _ 20 dB from 2.6 mm to 5.0 mm. In addition, the sulfidation process optimized the morphology, composition, interface, defects and conductivity, which further enhanced the EMW absorption performance of the material. The optimized RL (min) of S-doped Cu2_xSe reaches _ 44.5 dB at 1.9 mm with an EAB of 4.3 GHz.