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In this study, an infrared camouflage and radar compatible stealth structure based on metamaterial is designed and fabricated. Two types of frequency selective surfaces (FSS) with different infrared emissivity values are arranged into a specific pattern, which is similar to a visible camouflage pattern. The different infrared emissivity regions in the infrared camouflage layer (IRCL) are 0.27, 0.55, and 0.93, and the radar waves transmittance within 18 GHz is greater than 98%. Below the IRCL is a wideband radar metamaterial absorber based on square-ring resonant elements, which can absorb the radar waves and dissipate them through ohmic loss. The particle swarm optimization algorithm combined with the equivalent circuit model rapidly optimises the structure of the radar metamaterial abosrber, achieving an absorption rate greater than 90% from 4.5 GHz-18 GHz. And the absorption efficiency still maintains 80% at an oblique incidence range of 45°. The Indium Tin Oxide (ITO) film was etched by laser to obtain the above microstructures. The combination of two layers of metamaterial structure realizes the compatible stealth capability of infrared camouflage and radar absorption.

Assembling nanomaterials into hybrid structures provides a promising and flexible route to reach ultrahigh responsivity by introducing a trap‐assisted gain (G) mechanism. However, the high‐gain photodetectors benefitting from long carrier lifetime often possess slow response time (t) due to the inherent G–t tradeoff. Here, a light‐driven junction field‐effect transistor (LJFET), consisting of an n‐type ZnO belt as the channel material and a p‐type WSe2 nanosheet as a photoactive gate material, to break the G–t tradeoff through decoupling the gain from carrier lifetime is reported. The photoactive gate material WSe2 under illumination enables a conductive path for externally applied voltage, which modulates the depletion region within the ZnO channel efficiently. The gain and response time are separately determined by the field effect modulation and the switching speed of LJFET. As a result, a high responsivity of 4.83 × 103 A W−1 with a gain of ≈104 and a rapid response time of ≈10 µs are obtained simultaneously. The LJFET architecture offers a new approach to realize high‐gain and fast‐response photodetectors without the G–t tradeoff., The concept of a light‐driven junction field‐effect transistor (LJFET) is proposed to break the gain‐response time tradeoff for high‐gain phototransistors. The gain and response time are separately determined by the field effect modulation and the switching speed of LJFET. The design offers a new approach for photodetectors to reach high gain and fast response simultaneously.

For the first time, invariant super-elasticity from cryogenic 4 to 1273 K was observed for a bulk 3D cross-linked graphene foam., Until now, materials with high elasticity at deep cryogenic temperatures have not been observed. Previous reports indicated that graphene and carbon nanotube–based porous materials can exhibit reversible mechano-elastic behavior from liquid nitrogen temperature up to nearly a thousand degrees Celsius. Here, we report wide temperature–invariant large-strain super-elastic behavior in three-dimensionally cross-linked graphene materials that persists even to a liquid helium temperature of 4 K, a property not previously observed for any other material. To understand the mechanical properties of these graphene materials, we show by in situ experiments and modeling results that these remarkable properties are the synergetic results of the unique architecture and intrinsic elastic/flexibility properties of individual graphene sheets and the covalent junctions between the sheets that persist even at harsh temperatures. These results suggest possible applications for such materials at extremely low temperature environments such as those in outer space.

With the rapid development of detection technologies, compatible stealth in the infrared and radar ranges has become increasingly essential not only for military application but also for personal privacy protection. In this study, we design a metamaterial window that possesses stealth ability in both the thermal infrared and broadband microwave ranges, using a particle swarm optimization algorithm to realize multi-band optimization. We experimentally verify that the proposed structure can achieve over 90% microwave absorption in the range 5.1 to 19.2 GHz (covering the X and Ku bands), with low infrared emissivity (∼0.15), and also maintain visible transmittance above 60%. Moreover, the window retains good performance up to 200 °C owing to the intrinsic properties of the material. Our multi-band optimization method enables the application of the transparent metamaterial windows in electromagnetic shielding and stealth and can potentially be applied in smart window related industries.

It has been a great challenge to achieve the direct light manipulation of matter on a bulk scale. In this work the direct light propulsion of matter is observed on a macroscopic scale using a bulk graphene-based material. The unique structure and properties of graphene, and the novel morphology of the bulk three-dimensional linked graphene material make it capable not only of absorbing light at various wavelengths but also of emitting energetic electrons efficiently enough to drive the bulk material, following Newtonian mechanics. Thus, the unique photonic and electronic properties of individual graphene sheets are manifested in the response of the bulk state. These results offer an exciting opportunity to bring about bulkscale light manipulation with the potential to realize long-sought applications in areas such as the solar sail and space transportation driven directly by sunlight.

Smart actuators have many potential applications in various areas, so the development of novel actuation materials, with facile fabricating methods and excellent performances, are still urgent needs. In this work, a novel electromechanical bimorph actuator constituted by a graphene layer and a PVDF layer, is fabricated through a simple yet versatile solution approach. The bimorph actuator can deflect toward the graphene side under electrical stimulus, due to the differences in coefficient of thermal expansion between the two layers and the converse piezoelectric effect and electrostrictive property of the PVDF layer. Under low voltage stimulus, the actuator (length: 20 mm, width: 3 mm) can generate large actuation motion with a maximum deflection of about 14.0 mm within 0.262 s and produce high actuation stress (more than 312.7 MPa/g). The bimorph actuator also can display reversible swing behavior with long cycle life under high frequencies. on this basis, a fish-like robot that can swim at the speed of 5.02 mm/s is designed and demonstrated. The designed graphene-PVDF bimorph actuator exhibits the overall novel performance compared with many other electromechanical avtuators, and may contribute to the practical actuation applications of graphene-based materials at a macro scale.

It is a challenge to fabricate graphene bulk materials with properties arising from the nature of individual graphene sheets, and which assemble into monolithic three-dimensional structures. Here we report the scalable self-assembly of randomly oriented graphene sheets into additive-free, essentially homogenous graphene sponge materials that provide a combination of both cork-like and rubber-like properties. These graphene sponges, with densities similar to air, display Poisson's ratios in all directions that are near-zero and largely strain-independent during reversible compression to giant strains. And at the same time, they function as enthalpic rubbers, which can recover up to 98% compression in air and 90% in liquids, and operate between -196 and 900 °C. Furthermore, these sponges provide reversible liquid absorption for hundreds of cycles and then discharge it within seconds, while still providing an effective near-zero Poisson's ratio.