Sea Urchin-like SnS/Nitrogen-Doped Carbon Nanotube Dielectric Composites for Tunable Electromagnetic Response

Abstract

Owing to the unique energy band structure, semiconductor property, and adjustable morphology of two-dimensional SnS nanomaterials, it is extremely practical to employ them as dielectric microwave absorbers. However, electrical conductivity restricts the dielectric characteristic of SnS, resulting in a higher filling rate in real-world applications. Herein, sea urchin-like SnS/N-doped carbon nanotube (N-CNT) heterogeneous frameworks are fabricated by using the self-assembly solvothermal method to further upgrade the performance of SnS-based microwave absorbers. The flower-like SnS nanosheets are chained by way of one-dimensional conductive N-CNTs to shape three-dimensional (3D) hierarchical composites. In particular, the frameworks with a cross-linking nanoarchitecture provide an effective path to boost the conductive loss. Meanwhile, SnS nanosheets in the form of flowers with unique semiconductor properties offer a lot of polarization active sites, which encourage polarization loss. Furthermore, by optimizing the ratio of SnS and N-CNTs, the dielectric characteristics and impedance matching of the composites may be efficiently adjusted. The results certify that optimized SnS/N-CNT heterogeneous nanoframeworks exhibit thin thickness, lightweight, and strong absorption characteristics, which are recommended as promising microwave absorbers.

Porous Carbonaceous Aerogels Composed of Multiscale Carbon-Based Units for High-Performance Microwave Absorption

“…In general, a semicircle in the curve indicates a Debye relaxation process, and the existence of conductive loss may lead the Cole–Cole curve to deviate from the semicircular shape and form a reversely straight tail . The Cole–Cole curves of all aerogels are demonstrated in Figure and Figure S9, among which the RGO aerogel, RC aerogel, and RCT2 aerogel possess more abundant semicircles, suggesting the existences of active Debye relaxation, which immensely enhance the polarization loss . Therefore, it is reasonable to suppose that multiple polarization losses are mainly associated with the cross-polarization of CNCs when they interact with EMWs and the dipole polarization coming from RGO.…”