Sensitivity and pressure range are two significant parameters of pressure sensors. Existing pressure sensors have difficulty achieving both high sensitivity and a wide pressure range. Therefore, we ...propose a new pressure sensor with a ternary nanocomposite Fe
O
/C@SnO
. The sea urchin-like Fe
O
structure promotes signal transduction and protects Fe
O
needles from mechanical breaking, while the acetylene carbon black improves the conductivity of Fe
O
. Moreover, one part of the SnO
nanoparticles adheres to the surfaces of Fe
O
needles and forms Fe
O
/SnO
heterostructures, while its other part disperses into the carbon layer to form SnO
@C structure. Collectively, the synergistic effects of the three structures (Fe
O
/C, Fe
O
/SnO
and SnO
@C) improves on the limited pressure response range of a single structure. The experimental results demonstrate that the Fe
O
/C@SnO
pressure sensor exhibits high sensitivity (680 kPa
), fast response (10 ms), broad range (up to 150 kPa), and good reproducibility (over 3500 cycles under a pressure of 110 kPa), implying that the new pressure sensor has wide application prospects especially in wearable electronic devices and health monitoring.
The development of camouflage methods, often through a general resemblance to the background, has recently become a subject of intense research. However, an artificial, active camouflage that ...provides fast response to color change in the full-visible range for rapid background matching remains a daunting challenge. To this end, we report a method, based on the combination of bimetallic nanodot arrays and electrochemical bias, to allow for plasmonic modulation. Importantly, our approach permits real-time light manipulation readily matchable to the color setting in a given environment. We utilize this capability to fabricate a biomimetic mechanical chameleon and an active matrix display with dynamic color rendering covering almost the entire visible region.
Along with the technology evolution for dense integration of high-power, high-frequency devices in electronics, the accompanying interfacial heat transfer problem leads to urgent demands for advanced ...thermal interface materials (TIMs) with both high through-plane thermal conductivity and good compressibility. Most metals have satisfactory thermal conductivity but relatively high compressive modulus, and soft silicones are typically thermal insulators (0.3 W m–1 K–1). Currently, it is a great challenge to develop a soft material with the thermal conductivity up to metal level for TIM application. This study solves this problem by constructing a graphene-based microstructure composed of mainly vertical graphene and a thin cap of horizontal graphene layers on both the top and bottom sides through a mechanical machining process to manipulate the stacked architecture of conventional graphene paper. The resultant graphene monolith has an ultrahigh through-plane thermal conductivity of 143 W m–1 K–1, exceeding that of many metals, and a low compressive modulus of 0.87 MPa, comparable to that of silicones. In the actual TIM performance measurement, the system cooling efficiency with our graphene monolith as TIM is 3 times as high as that of the state-of-the-art commercial TIM, demonstrating the superior ability to solve the interfacial heat transfer issues in electronic systems.
The porous hollow BaFe12O19/CoFe2O4 microrods were prepared by an easy and reproducible in situ synthetic method. Cotton cellulose was used as the sacrificial bio-template. The as-prepared hard/soft ...ferrite composites were homogeneously distributed on the surface of the microrods. It was demonstrated that the porous hollow microrods-like structure and the exchange-coupled interaction between hard and soft ferrites were beneficial to improve the microwave absorption properties. The weight content of the hard/soft ferrite composites was low to 60 wt%, whereas reflection loss could reach to −10 dB in the frequency range of 8.2–16.3 GHz. The fabrication of porous hollow BaFe12O19/CoFe2O4 microrods was an efficient approach to solve the heavy mass problem of the conventional hard/soft ferrite matrix microwave absorption materials.
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•A kind of novel porous hollow BaFe12O19/CoFe2O4 composite microrods was investigated.•The weight content of the hard/soft ferrite composites was less to 60 wt%.•The reflection loss was reach to −10 dB in the frequency range of 8.2–16.3 GHz.
As the power density and integration level of electronic devices increase, there are growing demands to improve the thermal conductivity of polymers for addressing the thermal management issues. On ...the basis of the ultrahigh intrinsic thermal conductivity, graphene has exhibited great potential as reinforcing fillers to develop polymer composites, but the resultant thermal conductivity of reported graphene-based composites is still limited. Here, an interconnected and highly ordered graphene framework (HOGF) composed of high-quality and horizontally aligned graphene sheets was developed by a porous film-templated assembly strategy, followed by a stress-induced orientation process and graphitization post-treatment. After embedding into the epoxy (EP), the HOGF/EP composite (24.7 vol %) exhibits a record-high in-plane thermal conductivity of 117 W m–1 K–1, equivalent to ≈616 times higher than that of neat epoxy. This thermal conductivity enhancement is mainly because the HOGF as a filler concurrently has high intrinsic thermal conductivity, relatively high density, and a highly ordered structure, constructing superefficient phonon transport paths in the epoxy matrix. Additionally, the use of our HOGF/EP as a heat dissipation plate was demonstrated, and it achieved 75% enhancement in practical thermal management performance compared to that of conventional alumina for cooling the high-power LED.
High sinterability nano-Y
2
O
3
powders for transparent ceramics were successfully synthesized via the decomposition of hydroxyl-carbonate precursors from spray coprecipitation. The chemical ...composition of the precursor was determined as Y(CO
3
)(OH)·
n
H
2
O (
n
= 1–1.5), and it was evolved into Y
2
O
3
particles with clear facets after calcination with the assistance of sulfate. Two dispersion mechanisms, “absorption” and “intercalation,” were proposed to work together to provide the dispersion effect. Microstructural and optical characterization of powders and as-fabricated transparent ceramics was employed to evaluate the sintering behavior of powders. The nanopowders calcined at 1250 °C had weakly agglomerated morphology with the mean particle size of ~140 nm and exhibited excellent sinterability. The in-line transmittance of Y
2
O
3
ceramic of 1 mm thickness that was vacuum sintered at 1800 °C for 8 h without any sintering additives reached 78.7% at 1064 nm.
NiCoP nanothorns were in-situ grown on 3D porous Ni film, and the porous architecture could enhance the electrochemical surface area and active sites. The electrodes exhibited remarkable stability ...for long-term HER.
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Highly efficient, cost-effective, and durable electrocatalysts for hydrogen evolution reaction (HER) in water splitting is crucial for energy conversion and storage. Herein, we report NiCoP 1D nanothorn arrays grown on 3D porous Ni film current collectors (Ni/NiCoP) as the novel electrocatalytic electrodes. The 3D hierarchically porous nickel films containing large 7 ± 2 μm pores and small pores less than 1 μm are obtained through using hydrogen bubbles dynamic template method. The NiCoP 1D nanothorns are about 70 nm in diameter and 4–8 μm in length. The porous Ni/NiCoP electrocatalytic electrodes demonstrate much higher catalytic activity and remarkable stability for long-term HER. The excellent electrocatalytic performance might be attributed to the inherent nature of highly catalytic active NiCo bimetal phosphides and the unique architecture of 1D nanothorn active materials directly integrated on the 3D hierarchically porous metallic nickel conductive skeletons. The developed electrode has been fabricated to the integrated solar-driven seawater-splitting system.
The effects of graphene growth parameters on the number of its layers were systematically studied and a new growth mechanism on Cu substrate was thus proposed. Through the investigation of the ...graphene growth parameters, including growth substrate types, carrier gases, types of carbon sources, growth temperature, growth time, and cooling rates, we found that graphene grows on Cu substrates via a surface-catalyzed process, followed by a templated growth. We can obtain either single layer graphene (SLG) or few-layer graphene (FLG) by suppressing the subsequent templated growth with a low concentration of carbon source gases and a high concentration of H2. Our findings provide important guidance toward the synthesis of large-scale and high-quality FLGs and SLGs. This is expected to widen both the research and applications of graphene.
Elliptic Cu–Ag nanoflakes were syntheszied via facile in situ galvanic replacement between prepared Cu particles and Ag ions. Alloy nanoflakes with high purity and uniformity present a size of 700 × ...500 nm, with a thinness of 30 nm. Nontoxic and low-cost polyvinyl pyrrolidone was used as a dispersant and structure-directing agent, promoting the formation of the remarkable structure. Synthesized nanoflakes were utilized as a filler for conductive paste in an epoxy resin matrix. Conductive patterns on flexible substrates with a resistivity of 3.75 × 10–5 Ω·cm could be achieved after curing at 150 °C for 2 h. Compared with traditional silver microflakes, smart alloy nanoflakes provide much improved conductive interconnection, whose advantage could be attributed to their nanoscale thicknesses. It is also noteworthy that the conductive patterns are able to tolerate multiple bendings at different angles, having good conductivity even after 200 repeated bendings. Therefore, alloy nanoflakes could be a promising candidate conductive filler for flexible printing electronics, electronic packaging, and other conductive applications.
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