In recent years, the possible applications for double-walled carbon nanotubes have excited scientists and engineers, particularly those working on developing renewable energy technologies. These tiny tubes, just two carbon atoms thick, are thin enough to be transparent, yet can still conduct electricity. This combination makes them well-suited for advanced solar panels, sensors and a host of other applications.

Up until now, the problem with double-walled carbon nanotubes has been being able to produce a homogeneous supply of them. When double-walled carbon nanotubes are synthesized, the process also creates many of the single- and multi-walled variety. Given their small size, sorting the valuable double-walled tubes from the other types has posed a real challenge.

In a paper published today in the online edition of the journal Nature Nanotechnology, two researchers from Northwestern University outline a new process for efficiently gathering up these coveted double-walled carbon nanotubes. For more information on the team's work, go to http://www.northwestern.edu/newscenter/stories/2008/12/nanotube.html.