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Category: nanotechnology – Page 265

Researchers at the University of Minnesota and University of Milano-Bicocca are bringing the dream of windows that can efficiently collect solar energy one step closer to reality thanks to high tech silicon nanoparticles.

The researchers developed technology to embed the nanoparticles into what they call efficient (LSCs). These LSCs are the key element of windows that can efficiently collect solar energy. When light shines through the surface, the useful frequencies of light are trapped inside and concentrated to the edges where small solar cells can be put in place to capture the energy.

The research is published today in Nature Photonics.

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Nice.

Lawrence Livermore scientists have collaborated with an interdisciplinary team of researchers including colleagues from Sandia National Laboratories to develop an efficient hydrogen storage system that could be a boon for hydrogen powered vehicles.

Hydrogen is an excellent energy carrier, but the development of lightweight solid-state materials for compact, low-pressure storage is a huge challenge.

Complex metal hydrides are a promising class of materials, but their viability is usually limited by slow hydrogen uptake and release. Nanoconfinement—infiltrating the metal hydride within a matrix of another material such as carbon—can, in certain instances, help make this process faster by shortening diffusion pathways for hydrogen or by changing the thermodynamic stability of the material.

Continue reading “Nano-sized hydrogen storage system increases efficiency” | >

Nice development — demonstrating that light can control product selectivity in complex chemical reactions can be performed reliably.

Atmospheric CO2 can be transformed into valuable hydrocarbons by reaction with H2, but CO is the favoured kinetic product. Here, Liu and co-workers show that plasmonic rhodium nanoparticles not only reduce the activation energy for CO2hydrogenation, but also photo-selectively produce methane.

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Nice find on nanoparticles and energy transfer — important in scalable devices, energy conservation, etc.

The development, design and the performance evaluation of rare-earth doped host materials is important for further optical investigation and industrial applications. Herein, we successfully fabricate KLu2F7 upconversion nanoparticles (UCNPs) through hydrothermal synthesis by controlling the fluorine-to-lanthanide-ion molar ratio. The structural and morphological results show that the samples are orthorhombic-phase hexagonal-prisms UCNPs, with average side length of 80 nm and average thickness of 110 nm. The reaction time dependent crystal growth experiment suggests that the phase transformation is a thermo-dynamical process and the increasing F−/Ln3+ ratio favors the formation of the thermo-dynamical stable phase — orthorhombic KLu2F7 structure. The upconversion luminescence (UCL) spectra display that the orthorhombic KLu2F7:Yb/Er UCNPs present stronger UCL as much as 280-fold than their cubic counterparts. The UCNPS also display better UCL performance compared with the popular hexagonal-phase NaREF4 (RE = Y, Gd). Our mechanistic investigation, including Judd-Ofelt analysis and time decay behaviors, suggests that the lanthanide tetrad clusters structure at sublattice level accounts for the saturated luminescence and highly efficient UCL in KLu2F7:Yb/Er UCNPs. Our research demonstrates that the orthorhombic KLu2F7 is a promising host material for UCL and can find potential applications in lasing, photovoltaics and biolabeling techniques.

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A new day for imaging.

Optical microscopes that use lenses to bounce photons off objects have trouble distinguishing nanometer-scale objects smaller than the imaging beam’s wavelength, such as proteins and DNA. An innovative ‘hyperlens’ designed at A* STAR can overcome optical diffraction limits by capturing high-resolution information held by short-lived or evanescent waves lurking near a target’s surface.

Hyperlens devices — composed of thin stacks of alternate metal and plastic layers — have raised prospects for capturing living biological processes in action with high–speed optics. Key to their operation are oscillating electrons, known as surface plasmons, that resonate with and enhance evanescent waves that appear when photons strike a solid object. The narrow wavelengths of evanescent beams give nanoscale resolution to images when the hyperlens propagates the images to a standard microscope.

Mass-production of current hyperlenses has stalled however because of their intricate fabrication— up to 18 different layer depositions may be required, each with stringent requirements to avoid signal degradation. “For perfect imaging, these layers need precisely controlled thickness and purity,” says Linda Wu, from the A* STAR Singapore Institute of Manufacturing Technology. “Otherwise, it’s hard to magnify the object sufficiently for a conventional microscope to pick up.”

Continue reading “Spiky Nanostructures Capture Life’s Fine Details” | >

And, we just started. Just wait — in the next 6 to 8 months; I will some amazing news to share on QBS and BMI. smile

An explosion of nanotechnology research and development is occurring as newly identified forms of carbon, including graphene, carbon nanotubes and nano-diamonds, pave the way for new products and industries.

This article is sponsored by Flinders University.

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DNA, the stuff of life, may very well also pack quite the jolt for engineers trying to advance the development of tiny, low-cost electronic devices.

Much like flipping your light switch at home — –only on a scale 1,000 times smaller than a human hair — –an ASU-led team has now developed the first controllable DNA switch to regulate the flow of electricity within a single, atomic-sized molecule. The new study, led by ASU Biodesign Institute researcher Nongjian Tao, was published in the advanced online journal Nature Communications ( DOI: 10.1038/ncomms14471).

“It has been established that charge transport is possible in DNA, but for a useful device, one wants to be able to turn the charge transport on and off. We achieved this goal by chemically modifying DNA,” said Tao, who directs the Biodesign Center for Bioelectronics and Biosensors and is a professor in the Fulton Schools of Engineering.

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Very cool.

A research group from Bar-Ilan University, in collaboration with French colleagues at CNRS Grenoble, has developed a unique experiment to detect quantum events in ultra-thin films. This novel research, to be published in the scientific journal Nature Communications, enhances the understanding of basic phenomena that occur in nano-sized systems close to absolute zero temperature.

Transitions, Phases and Critical Points

A phase transition is a general term for physical phenomena wherein a system transits from one state to another as a result of changing the . Everyday examples are the transition from ice to water (solid to liquid) at zero degrees centigrade, and from water to vapor (liquid to gas) at 100 degrees.

Continue reading “Scientists create a nano-trampoline to probe quantum behavior” | >

Luminescent solar concentrators (LSCs), which are flat panes of mostly transparent material that take sunlight (both diffuse and directed) and concentrate it at the panes’ edges, can be used as “photovoltaic windows,” which, as the name makes clear, collect solar energy while serving as ordinary windows. Now, researchers at the Università degli Studi di Milano-Bicocca and Glass to Power Srl (both of Milano, Italy) and the University of Minnesota (Minneapolis, MN) are lowering the potential cost of such windows by using silicon nanoparticles as the fluorescent absorber/emitter in the LSC windows.

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Optical nano-antennas are ideal to enhance light-matter interactions at the nanometer scale. Yet in most designs, the region of maximum field localization and enhancement, the “hotspot”, is not readily accessible since it is buried into the nanostructure.

In a recent collaboration between EPFL in Lausanne, Fresnel Institute in Marseille and ICFO groups led by ICREA Professors at ICFO Maria Garcia-Parajo and Niek van Hulst, researchers present a new nanofabrication technique that applies planarization, etch back and template stripping to expose the excitation hotspot at the surface.

The large flat surface arrays of in-plane nano-antennas feature gaps as small as 10 nm with sharp edges, excellent reproducibility and full surface accessibility of the hotspot confined region. The novel fabrication approach drastically improves the optical performance of plasmonic nano-antennas to yield giant fluorescence enhancement factors, together with nanoscale detection volumes in the 20 zepto-liter range.

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