Regulating the electromagnetic balance of materials by electron transfer for enhanced electromagnetic wave absorption

The fact that single dielectric loss materials have disadvantages of excessive conductivities and impedance mismatches has given rise to a large effort to develop effective strategies to fabricate electromagnetic wave (EMW) absorbing materials comprised of components that bring about a balance between dielectric loss and magnetic loss. Moreover, little is known about the essential features that regulate EMW absorption propensities. This study focused on the development of a new EMW absorbing material and gaining information about factors that govern EMW absorption abilities. The materials at the center of the effort are light weight and porous cobalt sulfonated phthalocyanine-reduced graphene oxide (CoSPc-rGO) aerogels that were synthesized by using a simple hydrothermal method followed by freeze-drying. The properties of these materials that contribute to the electromagnetic balance between dielectric and magnetic loss were elucidated by first formulating a reasonable hypothesis about how the relative orientation of the components in CoSPc-rGO govern p-conjugation and electron transfer from rGO to CoSPc, which is proposed to be a key factor contributing to the regulation of the electromagnetic balance. Polarization relaxation process of materials was analyzed in detail using a variety of approaches including theoretical calculation, spectroscopic measurements, and experimental and simulation studies. The fabricated CoSPc-rGO aerogels that contain an ultra-low content of 4% were found to exhibit an extraordinary microwave absorption performance associated with a strong reflection loss of -53.23 dB and a broad effective absorption bandwidth of 8.04 GHz. The results of this study should provide an effective guide for new designs of composite materials for EMW absorption.