Thermal infrared and broadband microwave stealth glass windows based on multi-band optimization.

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.

Ultralow dark current infrared photodetector based on SnTe quantum dots beyond 2 μm at room temperature.

Quantum dots (QDs) are promising materials used for room temperature mid-infrared (MIR) photodetector due to their solution processing, compatibility with silicon and tunability of band structure. Up to now, HgTe QDs is the most widely studied material for MIR detection. However, photodetectors assembled with HgTe QDs usually work under cryogenic cooling to improve photoelectric performance, greatly limiting their application at room temperature.

Reduced Graphene Oxide Conformally Wrapped Silver Nanowire Networks for Flexible Transparent Heating and Electromagnetic Interference Shielding.

Metal nanowire networks (MNNs) are promising as transparent electrode materials for a diverse range of optoelectronic devices and also work as active materials for electrical heating and electromagnetic interference (EMI) shielding applications. However, the relatively low performance and poor durability of MNNs are limiting the practical application of the resulting devices. Here, we report a controllable approach to enhance the conductivity and the stability of MNNs with their transmittance remaining unchanged, in which reduced graphene oxide conformally wrapped silver nanowire networks (AgNW@rGO networks) are synthesized by selective electrodeposition of GO nanosheets on AgNWs followed by a pulsed laser irradiation treatment.

Light-Driven WSe-ZnO Junction Field-Effect Transistors for High-Performance Photodetection.

Assembling nanomaterials into hybrid structures provides a promising and flexible route to reach ultrahigh responsivity by introducing a trap-assisted gain () mechanism. However, the high-gain photodetectors benefitting from long carrier lifetime often possess slow response time () due to the inherent - 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 WSe nanosheet as a photoactive gate material, to break the - tradeoff through decoupling the gain from carrier lifetime is reported.

Super-elasticity of three-dimensionally cross-linked graphene materials all the way to deep cryogenic temperatures.

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.

Flexible Mid-Infrared Radiation Modulator with Multilayer Graphene Thin Film by Ionic Liquid Gating.

Electrochromic devices with tunable infrared radiation can meet the steadily growing demands in energy saving and thermal camouflage applications. Here, a mid-infrared radiation modulator based on flexible multilayer graphene thin films gated by nonvolatile ionic liquid on both rigid and flexible substrates is designed. The thermal emissivity of the device decreases nearly 80% within 2 s with the accumulation of anions in the multilayer graphene.

Preparation of Ultra-Smooth Cu Surface for High-Quality Graphene Synthesis.

As grown graphene by chemical vapor deposition typically degrades greatly due to the presence of grain boundaries, which limit graphene's excellent properties and integration into advanced applications. It has been demonstrated that there is a strong correlation between substrate morphology and graphene domain density. Here, we investigate how thermal annealing and electro-polishing affects the morphology of Cu foils.

Photoprompted Hot Electrons from Bulk Cross-Linked Graphene Materials and Their Efficient Catalysis for Atmospheric Ammonia Synthesis.

Ammonia synthesis is the single most important chemical process in industry and has used the successful heterogeneous Haber-Bosch catalyst for over 100 years and requires processing under both high temperature (300-500 °C) and pressure (200-300 atm); thus, it has huge energy costs accounting for about 1-3% of human's energy consumption. Therefore, there has been a long and vigorous exploration to find a milder alternative process. Here, we demonstrate that by using an iron- and graphene-based catalyst, Fe@3DGraphene, hot (ejected) electrons from this composite catalyst induced by visible light in a wide range of wavelength up to red could efficiently facilitate the activation of N and generate ammonia with H directly at ambient pressure using light (including simulated sun light) illumination directly.

Construction of a Fish-like Robot Based on High Performance Graphene/PVDF Bimorph Actuation Materials.

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.

Highly Reversible and Recyclable Absorption under Both Hydrophobic and Hydrophilic Conditions using a Reduced Bulk Graphene Oxide Material.

A 3D crosslinked reduced bulk graphene oxide material with switchable absorption capability between hydrophobicity and hydrophilicity is achieved by a simple O3 and annealing treatment.

Graphene-Based Materials for Lithium-Ion Hybrid Supercapacitors.

Lithium-ion hybrid supercapacitors (LIHSs), also called Li-ion capacitors, have attracted much attention due to the combination of the rapid charge-discharge and long cycle life of supercapacitors and the high energy-storage capacity of lithium-ion batteries. Thus, LIHSs are expected to become the ultimate power source for hybrid and all-electric vehicles in the near future. As an electrode material, graphene has many advantages, including high surface area and porous structure, high electric conductivity, and high chemical and thermal stability, etc.

Broadband and tunable high-performance microwave absorption of an ultralight and highly compressible graphene foam.

The broadband and tunable high-performance microwave absorption properties of an ultralight and highly compressible graphene foam (GF) are investigated. Simply via physical compression, the microwave absorption performance can be tuned. The qualified bandwidth coverage of 93.

Three-dimensionally bonded spongy graphene material with super compressive elasticity and near-zero Poisson's ratio.

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.