Artist’s impression based on a real atomic force microscopy (AFM) image showing conductive supramolecular fibers trapped between two gold electrodes spaced 100 nm apart. Each plastic fiber is composed of several short fibers and is capable of transporting electrical charges with the same efficiency as a metal. |
Researchers
from CNRS and the Université de Strasbourg, headed by Nicolas
Giuseppone and Bernard Doudin, have succeeded in making highly
conductive plastic fibers that are only several nanometers thick. These
nanowires, for which CNRS has filed a patent, “self-assemble” when
triggered by a flash of light.
Inexpensive
and easy to handle, unlike carbon nanotubes, they combine the
advantages of the two materials currently used to conduct electric
current: metals and plastic organic polymers. In fact, their remarkable
electrical properties are similar to those of metals. In addition, they
are light and flexible like plastics, which opens up the possibility of
meeting one of the most important challenges of 21st century
electronics: miniaturizing components down to the nanometric scale. This
work has been published on Nature Chemistry‘s
website. The next step is to demonstrate that these fibers can be
industrially integrated within electronic devices such as flexible
screens, solar cells, etc.
In
previous work published in 20105, Giuseppone and his colleagues
succeeded for the first time in obtaining nanowires. To achieve this
feat, they chemically modified “triarylamines”, synthetic molecules that
have been used for decades by industry in Xerox photocopying processes.
Much to their surprise, they observed that in light and in solution,
their new molecules stacked up spontaneously in a regular manner to form
miniature fibers. These wires, a few hundred nanometers long, are made
up of what is known as the “supramolecular” assembly of several thousand
molecules.
In
collaboration with Doudin’s team, the researchers then studied the
electrical properties of these nanofibers in detail. This time, they
placed their molecules in contact with an electronic microcircuit
comprising gold electrodes spaced 100 nm apart. They then applied an
electric field between these electrodes.
Their
first important finding was that, when triggered by a flash of light,
the fibers self-assemble solely between the electrodes. The second
surprising result was that these structures, which are as light and
flexible as plastics, turn out to be capable of transporting
extraordinary current densities, above 2.106 A/cm2, approaching those of copper wire. In addition, they
have very low interface resistance with metals: 10,000 times below
that of the best organic polymers.
The
researchers now hope to demonstrate that their fibers can be used
industrially in miniaturized electronic devices such as flexible
screens, solar cells, transistors, printed nanocircuits, etc.
Source: Light-triggered Self-construction of Supramolecular Organic Nanowires as Metallic Interconnects
Source: CNRS
