With the booming development of electronic information technology, the problems caused by electromagnetic (EMs) waves have gradually become serious, and EM wave absorption materials are playing an essential role in daily life. Carbon nanostructures stand out for their unique structures and properties compared with the other absorption materials. Graphene, carbon nanotubes, and other special carbon nanostructures have become especially significant as EM wave absorption materials in the high‐frequency range. Moreover, various nanocomposites based on carbon nanostructures and other lossy materials can be modified as high‐performance absorption materials. Here, the EM wave absorption theories of carbon nanostructures are introduced and recent advances of carbon nanostructures for high‐frequency EM wave absorption are summarized. Meanwhile, the shortcomings, challenges, and prospects of carbon nanostructures for high‐frequency EM wave absorption are presented. Carbon nanostructures are typical EM wave absorption materials being lightweight and having broadband properties. Carbon nanostructures and related nanocomposites represent the developing orientation of high‐performance EM wave absorption materials.
Advanced wearable sensors for human motion detection are receiving growing attention and have great potential for future electronics. Herein, we demonstrate microcrack-assisted strain sensors using silver nanowires@patterned polydimethylsiloxane. Through designed percolating network microstructures, the strain sensors have significant inherent advantages, including simple fabrication processes and ultrahigh sensitivity far surpassing other stretchable sensing devices. Noteworthily, the strain sensors possess a tremendous gauge factor (GF) of 150 000 within a large stretchability of 60% strain range. The sensing mechanism depends on the change in electrical resistance, which is dramatically affected by a percolating-microcrack surface microstructure in the case of strain concentration of mechanical deformation. The superior sensing performance in conjunction with an appealing stretchability, reversibility, low creep and ultrahigh stability enables the strain sensors to act as wearable monitors and electronic skins for diverse applications, including but not limited to full-range detection of human body motions, as well as visual control of a light-emitting diode indicator, etc.
We report the preparation of nanocomposites of reduced graphene oxide with embedded Fe3O4/Fe nanorings (FeNR@rGO) by chemical hydrothermal growth. We illustrate the use of these nanocomposites as novel electromagnetic wave absorbing materials. The electromagnetic wave absorption properties of the nanocomposites with different compositions were investigated. The preparation procedure and nanocomposite composition were optimized to achieve the best electromagnetic wave absorption properties. Nanocomposites with a GO:α-Fe2O3 mass ratio of 1:1 prepared by annealing in H2/Ar for 3 h exhibited the best properties. This nanocomposite sample (thickness = 4.0 mm) showed a minimum reflectivity of–23.09 dB at 9.16 GHz. The band range was 7.4–11.3 GHz when the reflectivity was less than–10 dB and the spectrum width was up to 3.9 GHz. These figures of merit are typically of the same order of magnitude when compared to the values shown by traditional ferric oxide materials. However, FeNR@rGO can be readily applied as a microwave absorbing material because the production method we propose is highly compatible with mass production standards.