Advances in the understanding of how carbon nanotubes move charges created by light

Nov 12, 2012
Efficient energy transport in photovoltaic carbon nanomaterials.

(Phys.org)—A LANL team and collaborators have made advances in the understanding of how carbon nanotubes move charges created by light. The research has applications for cheap, all-carbon-based photovoltaics and light detection elements. Their work measures exciton transport (excitons are small packets of energy made up of positive and negative charges) in carbon nanotubes at room temperature in a colloidal environment. A colloid is a substance that is evenly distributed throughout another substance, generally with particles that are between 1 and 1,000 nanometers in size. The nature of the colloidal environment influences the transport of charge-neutral excitons along the backbone of a carbon nanotube.

The exciton transport is described as "disorder-limited," which means that the movement of the exciton packet is restricted because of the nature of the environment attached to the nanotube surface. Excitons can only go backwards and forwards because they are confined to the tube surface, similar to a ship traveling down a narrow river that cannot turn around but can only go in forward or reverse. In this system, the excitons travel a few in each direction before reversing.

The research team found that the nature of the interface between the tube and the environment around it strongly affects the efficiency of this back and forth transport. By controlling the colloidal environment for certain factors (some colloidal substances may enhance transport), they propose that excitons can travel over a factor of five farther than they would otherwise. In their experiments, traveled in carbon nanotubes exceeding that of any other known material, and they did so at room temperature.

Understanding what factors govern exciton flow is important for where neutral produced by sunlight must move to an interface where they can separate into positive and . This separation creates a voltage that could charge a battery.  It also yields insight into how to create effective light-gathering materials.

Nano Letters published this research.

Explore further: Nanomechanical sensors detect cancer from breath

add to favorites email to friend print save as pdf

Related Stories

Researchers develop a way to funnel solar energy

Sep 12, 2010

(PhysOrg.com) -- Using carbon nanotubes (hollow tubes of carbon atoms), MIT chemical engineers have found a way to concentrate solar energy 100 times more than a regular photovoltaic cell. Such nanotubes could ...

Physicists take inspiration from spilled milk

Aug 12, 2011

(PhysOrg.com) -- Two Lehigh physicists have developed an imaging technique that makes it possible to directly observe light-emitting excitons as they diffuse in a new material that is being explored for its ...

Substantial improvement in essential cheap solar cell process

Mar 20, 2008

A cheap alternative to silicon solar cells can be found in dye-sensitised solar cells. This type of cell imitates the natural conversion of sunlight into energy by, for instance, plants and light-sensitive bacteria. Annemarie ...

Recommended for you

Research proves nanobubbles are superstable

1 hour ago

The intense research interest in surface nanobubbles arises from their potential applications in microfluidics and the scientific challenge for controlling their fundamental physical properties. One of the ...

User comments : 0

More news stories

Research proves nanobubbles are superstable

The intense research interest in surface nanobubbles arises from their potential applications in microfluidics and the scientific challenge for controlling their fundamental physical properties. One of the ...

New breast cancer imaging method promising

The new PAMmography method for imaging breast cancer developed by the University of Twente's MIRA research institute and the Medisch Spectrum Twente hospital appears to be a promising new method that could ...

Using antineutrinos to monitor nuclear reactors

When monitoring nuclear reactors, the International Atomic Energy Agency has to rely on input given by the operators. In the future, antineutrino detectors may provide an additional option for monitoring. ...