Nanotubes harvest electrons

Nanotechnology researchers are working to construct materials at the level of molecules and atoms in order to produce substances that have specific, precise electrical properties.

Researchers from the University of Bologna and the University of Trieste in Italy, and the University of Notre Dame have found a way to alter carbon nanotubes so that they efficiently separate electrical charge. The method could lead to more efficient solar cells.

Carbon nanotubes are long, rolled-up sheets of carbon atoms that can be smaller than a nanometer in diameter and are a natural component of soot. A nanometer is the span of 10 hydrogen atoms.

The researchers attached ferrocene molecules to the wall of every hundredth nanotube in a jumble of nanotubes. A ferrocene molecules contains two flat carbon rings sandwiching an iron atom; the molecule will readily give up an electron. When visible light hits the altered nanotubes, the ferrocene molecules readily give up electrons, which are absorbed by the nanotubes.

The electrons can then be diverted to provide a useful flow electricity. The researchers are working on adding light collectors like dyes to the nanotubes.

The method could be used in practical applications in 10 to 20 years, according to the researchers. The work appeared in the September 11, 2003 issue of Angewandte Chemie International Edition.