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Nanotechnology Spotlight

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Showing Spotlights 1 - 8 of 112 in category Graphene (newest first):

 

Aligned carbon nanotube/graphene sandwiches for high-rate lithium-sulfur batteries

cnt-graphene-sandwichResearchers consider the rational combination of carbon nanotubes (CNTs) and graphene into three-dimensional hybrids an effective route to amplify the inherent physical properties at the macroscale. By in situ nitrogen doping and structural hybridization of carbon nanotubes and graphene, researchers have now successfully fabricated nitrogen-doped aligned carbon nanotube/graphene sandwiches. In this work, aligned CNTs and graphene layers were anchored to each other, constructing a sandwich-like hierarchical architecture with efficient 3D electron transfer pathways and ion diffusion channels.

Posted: Sep 12th, 2014

Multimodal graphene biosensor integrates optical, electrical, and mechanical signals

graphene_sensorAs a prime example of how the integration of multiple disparate nanotechnology fields allows the realization of novel or expanded functionalities, researchers have demonstrated a multimodal sensing device which integrates the functionalities of three traditional single mode sensors. Specifically, the team fabricated a graphene-based multimodal biosensing device, capable of transducing protein binding events into optical, electrical, and mechanical signals.

Posted: Sep 8th, 2014

An all-carbon optical diode for photonic computing

doped_grapheneResearchers have demonstrated the experimental realization of the first all-carbon optical diode that is ready for scalable integration along with being inherently broadband in operation with no restrictions on polarization or phase-matching criteria. As they show, harnessing the optical properties of graphene-based materials offers an opportunity to create the all-photonic analogs of diodes, transistors, and photonic logic gates that will one day enable construction of the first all-photonic computer.

Posted: Sep 1st, 2014

Crumpled graphene boosts performance of high-energy lithium storage materials

crumpled_grapheneA three-dimensional crumpled graphene-encapsulated nickel sulfide electrode is reported as a superior high-energy lithium storage material. Compared with an electrode without crumpled graphene encapsulation, the optimized electrode yields significant improvements, especially in the cycling stability and rate capability. This enhanced performance is attributed to the 3D framework providing high continuous electron pathway and more free space for charge and mass transfer, and the stabilizing effect of the crumpled graphene based stretchy shell.

Posted: Aug 6th, 2014

Questions arise on the stability of graphene as a platform for photocatalysis

graphene_flakesEver since its discovery in 2004, graphene has been considered a relatively stable, high surface area platform to anchor nanostructured catalyst materials for various electrochemical and photocatalytic applications. The emergence of solution-based graphene in the form of graphene oxide has enabled new wet-chemistry approaches to the creation of graphene-based nanocomposites. A new study raises questions about the long-term stability of reduced graphene oxide in an aqueous environment where hydroxyl radicals can be present as part of the photocatalytic reaction cycle.

Posted: Jul 28th, 2014

Lithium-doped graphene approaches the limits of transparency and conductivity

graphene_electrodeTransparent conductive coatings pervade modern technology. They are a critical component of optoelectronic devices such as smartphone and tablet displays as well as solar cells. The search for novel transparent electrode materials with good stability, high transparency and excellent conductivity is driven by the required trade-off between transparency and conductivity. In new work, researchers now have simultaneously increased the conductivity and transparency of ultra thin graphite by lithium intercalation.

Posted: Jul 24th, 2014

Layered nanosheet membranes for ultrafast molecule separation

nanofiltrationResearchers have developed a new separation membrane with 2D layered transition metal dichalcogenides (tungsten disulfide) for size-selective separation of small molecules of about 3 nm. The as-prepared WS2 membranes exhibit 5 times higher water permeance than graphene oxide membranes with similar rejection. To further improve the water permeance, they team employed ultrathin metal hydroxide nanostrands to create more fluidic channels while keeping the rejection rate of specific molecules unchanged.

Posted: Jun 17th, 2014

Graphene quantum dot band-aids disinfect wounds

antibacterial_applicationA growing body of medical nanotechnology research deals with the development of antibacterial applications, ranging from nanotechnology-based approaches for diagnosing superbugs to antimicrobial surface coatings and wound treatment with antibacterial nanomaterials. Especially silver nanomaterials have been used effectively against different bacteria, fungi and viruses but also carbon nanomaterials like nanotubes and graphene. In new work, researchers have now designed an antibacterial system combining graphene quantum dots with a low dose of a common medical reagent, hydrogen peroxide H2O2.

Posted: Jun 12th, 2014