Brighter future for carbon nanotubes

A scientist at the US Department of Energy’s Brookhaven National Laboratory has caused an individual carbon nanotube to emit light for the first time.

A scientist at the US Department of Energy’s Brookhaven National Laboratory (BNL), working with colleagues at the IBM T.J. Watson Research Centre, has caused an individual carbon nanotube to emit light for the first time.

This development may bring to fruition the many proposed applications for carbon nanotubes, such as in electronics and photonics development.

The light emission is the result of a process called “electron-hole recombination.” By running an electric current through a carbon nanotube negatively charged electrons in the nanotube molecule combine with positively charged “holes,” which are locations in the molecule where electrons are missing. When an electron fills a hole, it emits a photon.

“We produced infrared light by applying voltages to a specific type of nanotube such that many electrons and holes end up in the nanotube, where they combine. This makes the nanotube the world’s smallest electrically-controllable light emitter,” said James Misewich, a materials scientist at Brookhaven.

“It’s an exciting result, and my colleagues and I plan to continue studying the effect to determine the mechanisms behind it. For example, we hope to understand how to make the nanotubes emit other types of light, such as visible light, and how to increase the efficiency of the emission.”

According to BNL, carbon nanotubes do not yet have any mainstream practical applications, but researchers are investigating ways to use them in flat-panel displays or as reinforcements in building materials, due to their exceptional mechanical strength.

Misewich also suggested that, if additional research leads to an increased efficiency of nanotube light emission, the nanotubes could possibly be used in lighting applications.