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Showing Spotlights 937 - 944 of 2083 in category (newest first):


Separating metallic and semiconducting single-walled carbon nanotubes by 'scotch tape'

cnt_separationCurrent production methods for carbon nanotubes (CNTs) result in units with different diameter, length, chirality and electronic properties, all packed together in bundles, and often blended with some amount of amorphous carbon. Often, these mixtures are of little practical use since many advanced applications, especially for nanoelectronics, are sensitively dependent on the structures. Separation of nanotubes according to desired properties is still proving to be a challenging task, especially single-walled carbon nanotube (SWCNT) sorting. The composition of SWCNTs of different types is very similar, but the chemical properties are not. Conventional separation techniques are efficient in separation of carbon nanotubes, but there are many drawbacks. Researchers in Asia have now developed a simple way to realize the separation of single-walled carbon nanotubes via the interaction difference between chemicals and carbon nanotubes.

Posted: Jun 14th, 2011

Nano-PacMan caught on video - observing nanoparticle channelling in graphene in real-time

pacmanGraphene has two distinct types of edges produced when it is cut - armchair type or zigzag type - which correspond to the two crystal axis of graphene. These edge types have distinct electronic, magnetic, and chemical properties, and being able to pattern graphene along particular crystallographic directions to leave edges consisting of a single chirality is crucial for the fabrication of graphene nanoribbon and nanoelectronics devices. A widely discussed method for the patterning of graphene is the channelling of graphite by metal nanoparticles in oxidizing or reducing environments. Researchers now report the live nanoscale observation of this channelling process by silver nanoparticles.

Posted: Jun 13th, 2011

Fabricating polymer tandem solar cells with a graphene-based conductive glue

tandem_solar_cellApart from making graphene, graphene oxide itself itself is a fascinating material that has many intriguing properties. Researchers have now developed a graphene-based conductive glue that can function as a metal-free solder for creating mechanical and electrical connections in organic optoelectronic devices. As a proof-of-concept, they fabricated polymer tandem solar cells - multi-junction photovoltaic devices, in which two sub-cells are stacked to achieve higher overall solar absorption - by a direct 'gluing' process. The water-based sticky interconnect and the associated adhesive lamination process could transform the serial layer-by-layer fabrication of tandem devices into a parallel mode, in which the subcells can be independently fabricated and adjusted to balance their photocurrents for achieving high efficiency.

Posted: Jun 10th, 2011

Towards electronic textiles - putting conductive coatings on fibers

conductive_fibersThe future of your shirts, socks and gloves will be electronic. In years to come, wearable electronics will look nothing like even your smallest iPod or mobile phone today. Not only will such devices be embedded on textile substrates, but an electronics device or system could become the fabric itself. Here is some recent work that demonstrates the kind of issues scientists are working on today and that will help improve the performance of electronic textile structures. Using atomic layer deposition (ALD), researchers have grown coatings of inorganic materials on the surface of textiles like woven cotton and nonwoven polypropylene. By fabricating an all-fiber capacitor, they show that their coated materials are sufficiently conductive to perform in simple device architectures.

Posted: Jun 9th, 2011

New approach to strain engineering graphene circumvents current methods' limitations

grapheneUnlike silicon, graphene lacks an electronic band gap - the gap being an energy range that cannot be occupied by electrons - and therefore has no switching capability; which is essential for electronics applications. Opening an energy gap in graphene's electron energy spectrum is therefore a critical prerequisite for instance for creating graphene transistors. That's where strain engineering of graphene comes in. Researchers have discovered that local strain in a graphene sheet can alter its conducting properties. By varying the amount of local strain, transport gaps can be tailored. In new work, researchers present a new and novel mechanism for gap opening in strained graphene via electrostatic gates and show that it can be important also in realistic situations.

Posted: Jun 8th, 2011

A 'green' nanomaterial to remove organic impurities from waste water

water_decontaminationWater treatment is important for human consumption and environmental protection. Non-trivial purification of water involves removal of toxic ions, organic impurities, microbes and their by-products as well as scooping oil spills. The removal of organic contaminants from water is a major industrial concern. The challenging goal here is to detect, decompose and remove contaminants present usually in low concentrations. Towards this end, different types of sorbent materials have been developed to date, the most common being activated carbon. Though the use of activated carbon is still considered to be one of the best method, the disposal of adsorbed contaminants along with the adsorbent is a major concern. Researchers in India have recently come up with an innovative method for organic pollutant removal from waste water.

Posted: Jun 7th, 2011

Novel approach for highly sensitive detection of miRNA down to individual strands

miRNA_detection_assayMicroRNAs (miRNAs) are short ribonucleic acid molecules, consisting of 21-25 nucleotide bases, that negatively regulate gene expression, also termed as gene silencing. Each miRNA is thought to regulate multiple genes, and since the human genome encodes hundreds of miRNAs, the potential regulatory circuitry afforded by miRNA is enormous. Recent discoveries suggest the association of specific miRNA sequences with a spectrum of diseases including cardiovascular and autoimmune diseases, as well as with a variety of cancers. It is therefore imperative, for diagnostics and prognostics, to accurately measure the expression levels of target miRNA molecules in patients' tissue samples or body fluids. To that end, researchers have developed an alternative way for the direct analysis of miRNAs in an array format, demonstrating fast and ultrasensitive detection of specific miRNAs.

Posted: Jun 6th, 2011

First self-powered nanosystem with wireless data transmission

nanosystemFabrication of a single nanodevice is no longer the state of the art in nanotechnology. The leading edge - and also currently the most challenging area in nanotechnology - is research that leads to a self-powered nanoscale system that is driven by the energy harvested from its environment and that can perform its work independently and sustainable. This is a key step toward self-powered nanotechnology, which is vitally important for medical science, environmental monitoring, defence technology and even personal electronics. A research team has now provided the first demonstration that a nanogenerator can be strong enough to power a device with the capability of sensing, data processing and wireless data transmission. This is a powerful demonstration of the self-powered nanosystem and its potential applications.

Posted: Jun 1st, 2011