Integrated Ring Oscillators based on high-performance Graphene Inverters.
Ontology highlight
ABSTRACT:
SUBMITTER: Schall D
PROVIDER: S-EPMC3763254 | biostudies-other | 2013
REPOSITORIES: biostudies-other
Similar Datasets
Project description:This study reports on the development of a cementitious composite incorporating electrochemically exfoliated graphene (EEG). This hybrid functional material features significantly enhanced microstructure and mechanical properties, as well as unaffected workability; thus, it outperforms previously reported cementitious composites containing graphene derivatives. The manufacturing of the composite relies on a simple and efficient method that enables the uniform dispersion of EEG within cement matrix in the absence of surfactants. Different from graphene oxide, EEG is found to not agglomerate in cement alkaline environment, thereby not affecting the fluidity of cementitious composites. The addition of 0.05 wt% graphene content to ordinary Portland cement results in an increase up to 79%, 8%, and 9% for the tensile strength, compressive strength, and Young's modulus, respectively. Remarkably, it is found that the addition of EEG promotes the hydration reaction of both alite and belite, thus leading to the formation of a large fraction of 3CaO·2SiO2·3H2O (C-S-H) phase. These findings represent a major step forward toward the practical application of nanomaterials in civil engineering.
| S-EPMC6498302 | biostudies-literature
Project description:In this paper, graphene oxide/styrene-butadiene rubber (GO/SBR) composites with complete exfoliation of GO sheets were prepared by aqueous-phase mixing of GO colloid with SBR latex and a small loading of butadiene-styrene-vinyl-pyridine rubber (VPR) latex, followed by their co-coagulation. During co-coagulation, VPR not only plays a key role in the prevention of aggregation of GO sheets but also acts as an interface-bridge between GO and SBR. The results demonstrated that the mechanical properties of the GO/SBR composite with 2.0 vol.% GO is comparable with those of the SBR composite reinforced with 13.1 vol.% of carbon black (CB), with a low mass density and a good gas barrier ability to boot. The present work also showed that GO-silica/SBR composite exhibited outstanding wear resistance and low-rolling resistance which make GO-silica/SBR very competitive for the green tire application, opening up enormous opportunities to prepare high performance rubber composites for future engineering applications.
| S-EPMC3752610 | biostudies-literature
Project description:The inherent zero-band gap nature of graphene and its fast photocarrier recombination rate result in poor optical gain and responsivity when graphene is used as the light absorption medium in photodetectors. Here, semiconducting graphene nanoribbons with a direct bandgap of 1.8 eV are synthesized and employed to construct a vertical heterojunction photodetector. At a bias voltage of -5 V, the photodetector exhibits a responsivity of 1052 A/W, outperforming previous graphene-based heterojunction photodetectors by several orders of magnitude. The achieved detectivity of 3.13 × 1013 Jones and response time of 310 μs are also among the best values for graphene-based heterojunction photodetectors reported until date. Furthermore, even under zero bias, the photodetector demonstrates a high responsivity and detectivity of 1.04 A/W and 2.45 × 1012 Jones, respectively. The work shows a great potential of graphene nanoribbon-based photodetection technology.
| S-EPMC10786164 | biostudies-literature
Project description:Graphene-oxide (GO) membrane with notable ions sieving properties has attracted significant attention for many applications. However, because of the water swelling of GO membrane, the rejection of monovalent metal cations is generally low. In this work, we developed a fast and facile method to fabricate a kind of reduced GO membranes using the thermal treatment method at 160 °C for only one minute, which denoted as fast reduced GO membrane (FRGO). Surprising, the FRGO membrane represents high ion sieving ability and ultrahigh water/ions selectivity, compared with other reduced GO membranes with similar average interlayer spacings, and even superior to most of GO-based membranes reported in literature. Building on these findings, we provide a new light on fabricating of energy- and environment-related high desalination performance of GO-based membranes as well as a new insight into the transport mechanism within 2D laminar nanochannels.
| S-EPMC8619719 | biostudies-literature
Project description:Sodium-ion batteries (SIBs) are emerging as a promising alternative to conventional lithium-ion technology, due to the abundance of sodium resources. The major drawbacks for the commercial application of SIBs lie in the slow kinetic processes and poor energy density of the devices. Molybdenum sulfide (MoS2), a graphene-like material, is becoming a promising anode material for SIBs, because of its high theoretical capacity (670 mAh g-1) and layered structure that suitable for Na+ intercalation/extraction. However, the intrinsic properties of MoS2, such as low conductivity, slow Na+ diffusion kinetics and large volume change during charging/discharging, restrict its rate capability and cycle stability. Here, molybdenum disulfide and graphene oxide (3D MoS2/GO) with excellent conductivity were fabricated through layer-by-layer method using amino-functionalized SiO2 nanospheres as templates. The 3D MoS2/GO composite demonstrates excellent cycling stability and capacity of 525 mA h g-1 at 500 mA g-1 after 100 cycles, which mainly due to the integrated MoS2/GO components and unique 3D macroporous structure, facilitating the material conductivity and Na+ diffusion rate, while tolerating the volume expansion of MoS2 during the charge/discharge processes.
| S-EPMC11336104 | biostudies-literature
Project description:Commonly used energy storage devices include stacked layers of active materials on two-dimensional sheets, and the limited specific surface area restricts the further development of energy storage. Three-dimensional (3D) structures with high specific surface areas would improve device performance. Herein, we present a novel procedure to fabricate macroscopic, high-quality, nitrogen-doped, 3D graphene/nanoparticle aerogels. The procedure includes vacuum filtration, freeze-drying, and plasma treatment, which can be further expanded for large-scale production of nitrogen-doped, graphene-based aerogels. The behavior of the supercapacitor is investigated using a typical nitrogen-doped graphene/Fe3O4 nanoparticle 3D structure (NG/Fe3O4). Compared with 3D graphene/Fe3O4 structures prepared by the traditional hydrothermal method, the NG/Fe3O4 supercapacitor prepared by the present method has a 153% improvement in specific capacitance, and there is no obvious decrease in specific capacitance after 1000 cycles. The present work provides a new and facile method to produce large-scale, 3D, graphene-based materials with high specific capacitance for energy storage.
| S-EPMC6059830 | biostudies-literature
Project description:Incorporating the influence of induced polarization in large-scale atomistic molecular dynamics (MD) simulations is a critical challenge in the progress toward computations of increased accuracy. One computationally efficient treatment is based on the classical Drude oscillator in which an auxiliary charged particle is attached by a spring to each nucleus. Here, we report the first implementation of this model in the program NAMD. An extended Lagrangian dynamics with a dual-Langevin thermostat scheme applied to the Drude-nucleus pairs is employed to efficiently generate classical dynamic propagation near the self-consistent field limit. Large-scale MD simulations based on the Drude polarizable force field scale very well on massively distributed supercomputing platforms, the computational demand being only about 50-100% higher than for nonpolarizable models. As an illustration, a large-scale 150 mM NaCl aqueous salt solution is simulated, and the calculated ionic conductivity is shown to be in excellent agreement with experiment.
| S-EPMC3092300 | biostudies-literature
Project description:Graphene quantum dots (GQDs) have received much attention due to their novel phenomena of charge transport and light absorption/emission. The optical transitions are known to be available up to ~6?eV in GQDs, especially useful for ultraviolet (UV) photodetectors (PDs). Thus, the demonstration of photodetection gain with GQDs would be the basis for a plenty of applications not only as a single-function device in detecting optical signals but also a key component in the optoelectronic integrated circuits. Here, we firstly report high-efficient photocurrent (PC) behaviors of PDs consisting of multiple-layer GQDs sandwiched between graphene sheets. High detectivity (>10(11)?cm Hz(1/2)/W) and responsivity (0.2 ~ 0.5 A/W) are achieved in the broad spectral range from UV to near infrared. The observed unique PD characteristics prove to be dominated by the tunneling of charge carriers through the energy states in GQDs, based on bias-dependent variations of the band profiles, resulting in novel dark current and PC behaviors.
| S-EPMC4083259 | biostudies-literature
Project description:Performance of an electronic device relies heavily on the availability of a suitable functional material. One of the simple, easy, and cost-effective ways to obtain novel functional materials with improved properties for desired applications is to make composites of selected materials. In this work, a novel composite of transparent n-type zinc oxide (ZnO) with a wide bandgap and a unique structure of graphene in the form of a graphene flower (GrF) is synthesized and used as the functional layer of a humidity sensor. The (GrF/ZnO) composite was synthesized by a simple sol-gel method. Morphological, elemental, and structural characterizations of GrF/ZnO composite were performed by a field emission scanning electron microscope (FESEM), energy-dispersive spectroscopy (EDS), and an x-ray diffractometer (XRD), respectively, to fully understand the properties of this newly synthesized functional material. The proposed humidity sensor was tested in the relative humidity (RH) range of 15% RH% to 86% RH%. The demonstrated sensor illustrated a highly sensitive response to humidity with an average current change of 7.77 μA/RH%. Other prominent characteristics shown by this device include but were not limited to high stability, repeatable results, fast response, and quick recovery time. The proposed humidity sensor was highly sensitive to human breathing, thus making it a promising candidate for various applications related to health monitoring.
| S-EPMC7831307 | biostudies-literature
Project description:Graphene/silicon Schottky junctions have been proven efficient for photodetection, but the existing high dark current seriously restricts applications such as weak signal detection. In this paper, a thin layer of gadolinium iron garnet (Gd3Fe5O12, GdIG) film is introduced to engineer the interface of a graphene/silicon Schottky photodetector. The novel structure shows a significant decrease in dark current by 54 times at a -2 V bias. It also exhibits high performance in a self-powered mode in terms of an Ilight/Idark ratio up to 8.2 × 106 and a specific detectivity of 1.35 × 1013 Jones at 633 nm, showing appealing potential for weak-light detection. Practical suitability characterizations reveal a broadband absorption covering ultraviolet to near-infrared light and a large linear response with a wide range of light intensities. The device holds an operation speed of 0.15 ms, a stable response for 500 continuous working cycles, and long-term environmental stability after several months. Theoretical analysis shows that the interlayer increases the barrier height and passivates the contact surface so that the dark current is suppressed. This work demonstrates the good capacity of GdIG thin films as interlayer materials and provides a new solution for high-performance photodetectors.
| S-EPMC8741776 | biostudies-literature