We propose all-dielectric metasurfaces that can be actively re-configured using the phase-change material Ge 2 Sb 2 Te 5 (GST) alloy. With selectively controlled phase transitions on the composing GST elements, metasurfaces can be tailored to exhibit varied functionalities. Using phase-change GST rod as the basic building block, we have modelled metamolecules with tunable optical response when phase change occurs on select constituent GST rods. Tunable gradient metasurfaces can be realized with variable supercell period consisting of different patterns of the GST rods in their amorphous and crystalline states. Simulation results indicate a range of functions can be delivered, including multilevel signal modulating, near-field coupling of GST rods, and anomalous reflection angle controlling. This work opens up a new space in exploring active meta-devices with broader applications that cannot be achieved in their passive counterparts with permanent properties once fabricated.

Electromagnetic protection in optoelectronic instruments such as optical windows and electronic displays is challenging because of the essential requirements of a high optical transmittance and an electromagnetic interference (EMI) shielding effectiveness (SE). Herein, we demonstrate the creation of an efficient transparent EMI shielding film that is composed of calcium alginate (CA), silver nanowires (AgNWs), and polyurethane (PU), via a facile and low-cost Mayer-rod coating method. The CA/AgNW/PU film with a high optical transmittance of 92% achieves an EMI SE of 20.7 dB, which meets the requirements for commercial shielding applications. A superior EMI SE of 31.3 dB could be achieved, whereas the transparent film still maintains a transmittance of 81%. The integrated efficient EMI SE and high transmittance are superior to those of most previously reported transparent EMI shielding materials. Moreover, our transparent films exhibit a highly reliable shielding ability in a complex service environment, with 98 and 96% EMI SE retentions even after 30 min of ultrasound treatment and 5000 bending cycles (1.5 mm radius), respectively. The comprehensive performance that is associated with the facile fabrication strategy imparts the CA/AgNW/PU film with great potential as an optimized EMI shielding material in emerging optoelectronic devices, such as flexible solar cells, displays, and touch panels.

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Hydrothermally prepared vertical multilayer WS2 nanosheets on the surface of few-layer MoS2 for the ultra-sensitive NO2 detection at room temperature.

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A strong and tough CNT-NR film with excellent EMI SE (44.7 dB@250 μm) is realized.

Constructing segregated structure in conductive polymer composite (CPC) is effective to achieve high electromagnetic interference shielding effectiveness (EMI SE) at low filler loading. Nevertheless, the present segregated CPCs were only fabricated via the compression molding technique, which limits their practical application. In this work, the injection molding technique was utilized for the first time to develop a carbon nanotube (CNT)/isotactic polypropylene (iPP)/atactic polypropylene (aPP) composite with typical segregated structure. The injection molded segregated CNT/PP composite exhibits an excellent EMI SE of 43.1 dB, which is 67% higher than the CNT/PP composite with randomly distributed CNTs, at the same CNT loading of 5.0 wt %. Such EMI SE is also comparable to the value for segregated CNT/PP composites prepared by compression molding. Our work provides a promising strategy to develop segregated CPCs via an efficient injection molding technique, in comparison to the compression molding technique.

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