Friday, May 28, 2010

This week in nanotechnology - May 28, 2010

Nanotechnology researchers build transistor with just seven atoms. Scientists have literally taken a leap into a new era of computing power by making the world's smallest precision-built transistor - a 'quantum dot' of just seven atoms in a single silicon crystal. Despite its incredibly tiny size - a mere four billionths of a meter long - the quantum dot is a functioning electronic device, the world's first created deliberately by placing individual atoms.

Creating catalysts that can operate efficiently and last a long time is a big barrier to taking fuel-cell technology from the lab bench to the assembly line. The precious metal platinum has been the choice for many researchers, but platinum has two major downsides: It is expensive, and it breaks down over time in fuel-cell reactions. In a new study, chemists have created a unique core and shell nanoparticle that uses far less platinum yet performs more efficiently and lasts longer than commercially available pure-platinum catalysts at the cathode end of fuel-cell reactions.

Graphane is the material of choice for physicists on the cutting edge of materials science. Researchers at Rice University have discovered the strategic extraction of hydrogen atoms from a two-dimensional sheet of graphane naturally opens up spaces of pure graphene that look - and act - like quantum dots. That opens up a new world of possibilities for an ever-shrinking class of nanoelectronics that depend on the highly controllable semiconducting properties of quantum dots, particularly in the realm of advanced optics.

microlens


Rice researchers created these fanciful images of electron densities from their graphane-embedded quantum dot calculations. The isosurfaces depict electrons in the valance band that, in reality, would be confined within the quantum dot, and demonstrate that very little charge would leak from the hydrogen-defined boundaries of such a dot.


Researchers have discovered thin films of nanotubes created with ink-jet printers offer a new way to make field-effect transistors (FET), the basic element in integrated circuits. While the technique doesn't exactly scale down to the levels required for modern microprocessors, it could be useful to inventors who wish to print transistors on materials of any kind, especially on flexible substrates.

Jeffrey Long’s lab will soon host a round-the-clock, robotically choreographed hunt for carbon-hungry materials.
The Berkeley Lab chemist leads a diverse team of scientists whose goal is to quickly discover materials that can efficiently strip carbon dioxide from a power plant’s exhaust, before it leaves the smokestack and contributes to climate change. They’re betting on a recently discovered class of materials called metal-organic frameworks that boast a record-shattering internal surface area. A sugar cube-sized piece, if unfolded and flattened, would more than blanket a football field. The crystalline material can also be tweaked to absorb specific molecules. The idea is to engineer this incredibly porous compound into a voracious sponge that gobbles up carbon dioxide.

Imagine creating novel devices with amazing and exotic optical properties not found in Nature - by simply evaporating a droplet of nanoparticles on a surface. By chemically building clusters of nanospheres from a liquid, a team of Harvard researchers, in collaboration with scientists at Rice University, the University of Texas at Austin, and the University of Houston, has developed just that.