Herein, we attempt to summarize the scientific roadmap of various strategies adopted in the past few years towards screening EM radiation using multi-layered sandwich architectures.

Herein, we report high electromagnetic interference (EMI) shielding effectiveness of -40 dB in the K-band (for a 600 μm thick film) through a unique core-shell heterostructure consisting of a ferritic core (FeO) and a conducting shell (multiwalled carbon nanotubes, MWCNTs) supported onto a dielectric spacer (here SiO). In recent times, materials with good flexibility, heat dissipation ability, and sustainability together with efficient EMI shielding at minimal thickness are highly desirable, especially if they can be easily processed into thin films. The resulting composites here shielded EM radiation mostly through absorption driven by multiple interfaces provided by the heterostructure. The shielding value obtained here is fairly superior among the different polymer nanocomposite-based EMI shielding materials. In addition to EMI shielding capability, this composite material exhibits outstanding heat dissipation ability (72 °C to room temperature in less than 90 s) as well as high heat sustainability. The composite material retained its EMI shielding property even after repeated heat cycles, thereby opening new avenues in the design of lightweight, flexible, and sustainable EMI shielding materials.

Core–shell nanoparticles are a unique class of nanostructured materials, which received significant attention in the last two decades owing to their exciting properties and a wide variety of applications. By judiciously tuning the “core” as well as the “shell”, an assortment of “core–shell” nanostructures can be obtained with tailorable properties which can play pivotal roles in designing materials for electromagnetic interference (EMI) shielding and microwave absorption. In recent times when the use of high-end electronics has been on the rise, electromagnetic pollution is inevitable and it affects every walk of life. Among numerous e-pollutions, a recently highlighted domain that has far-reaching consequences is electromagnetic interference. EMI is the disturbance created during an electronic device’s operation when it is in the vicinity of an electromagnetic field caused by another electronic or electric device. Since EMI decreases the lifetime and degrades the performance of the electronic instruments and even affects human health, it is crucial to protect sophisticated instruments and components from EM interference. High-performance EMI shields capable of attenuating microwave propagation efficiently have been developed in the past decade. Herein, in this review, we attempted to provide a logical guide to various “core–shell” nanostructures (≤500 nm) that have been synthesized in the past decade for the application in microwave absorption and EMI shielding. The prime focus of this review article is to highlight the fundamental concept of EMI shielding and microwave absorption that have been reported for various systems in the literature along with various synthetic and fabrication strategies in designing suitable broadband EM absorbers/screeners. Finally, we also made an effort to provide a holistic outlook and perspective in which upcoming research will continue to flourish.

Precisely probing heavy metal pollutants in water warrants novel methods and materials. To this end, functionalisation of nanoparticles using biologically important substances through a green route is one of the novel aspects for the design of an optical sensor. In this article we report a green preparative strategy for the synthesis of cysteamine stabilized silver nanoparticles (Ag-Nps) in aqueous medium. The water soluble Ag-Nps are found to be highly sensitive and selective for rapid colorimetric detection of Hg(II) ion with a limit of detection (LOD) of 0.273 nM (55 ppt). This system also enables us to detect Hg(II) through naked eye with a LOD of 2.73 nM (0.55 ppb) which is below the WHO permissible limit (10 nM or 2 ppb).Cysteamine undergoes cooperative coordination with the mercury ion leading to spontaneous formation of mercury-cysteamine complex and consequently forms Ag-Hg nano-alloy, which in turn changes the surface plasmon property of the Ag-Nps to allow detection of Hg(II) ion with sub-nanomolar precision. Furthermore, the Ag-Nps were tested for detection of Hg(II) in different real water samples with satisfying recoveries over 96-102 %.