Conductive Nanofibers Self-Organize Under Light

New flexible nanofibers that can self-assemble under a flash of light combine the best advantages of two materials currently used to conduct electric current: metals and plastic organic polymers.

Artist’s impression of conductive supramolecular fibers trapped between two gold electrodes spaced 100 nm apart. Each plastic fiber is composed of several short fibers and can transport electrical charges with the same efficiency as the best metals. (Images: ©M. Maaloum, ICS [CNRS])

The nanofibers can be integrated into electronic devices such as flexible screens and solar cells and are easier to fabricate and handle than carbon ones. They also can conduct electricity as well as the best metals, a feature that will enable them to be used in nanoscale electronic components.

Real atomic force microscopy image showing a conductive supramolecular fiber composed of several short fibers. Each grain corresponds to a molecule (the image is 50 nm in height).

A research group headed by Nicolas Giuseppone of the Centre National de la Reserche Scientifique (CNRS) and Bernard Doudin of the University of Strasbourg previously found that chemically modified synthetic molecules called triarylamines — which have been used in photocopying processes for decades — exhibit self-organizing behaviors when exposed to light. Several thousand of the molecules come together to form ultrathin nanofibers.

The researchers then studied the conductive properties of the fibers. They placed the molecules in an electronic microcircuit containing gold electrodes spaced 100 nm apart and applied an electric field.

They found that the molecules in the microcircuit ordered themselves between the electrodes and transported immense current densities — almost as well as copper wire.

The fibers also are as flexible as plastic and have an incredibly low interface resistance with metals.

The work was published April 22 on Nature Chemistry's website.

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