Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Taking charge of molecular wires

23.08.2004


Scientists from the U.S. Department of Energy’s Brookhaven National Laboratory and the University of Florida have uncovered information that may help "molecular wires" replace silicon in micro-electronic circuits and/or components in solar energy storage systems. The scientists were studying how electric charge is distributed in polymer molecule chains that are several nanometers, or billionths of a meter, in length.



Brookhaven chemist John Miller, the study’s lead scientist, will present the group’s results on Sunday, August 22, 2004, at the 228th national meeting of the American Chemical Society in Philadelphia, Pennsylvania (Pennsylvania Convention Center, Ballroom B, 2:45 p.m.).

"Long molecules that can act as molecular wires, of which there are many variations, are one type of nanoscale object with the potential to lead to new technologies, due to their ability to conduct electricity and very small size," said Miller. "But unlike conventional metal wires, polymer nanowires need assistance in order to conduct."


"Using a cluster of high-energy electrons from an accelerator, we can quickly add an extra negative or positive charge to a polymer molecular wire. When the end of the wire contains a chemically-attached ’trap’ molecule, one where the electrons will be at a lower, more stable energy, the charge moves to it. This allows us to ’see’ that the wires conduct electrons quickly, and over long distances."

One potential application for this finding is in the solar energy industry, particularly in a new field called "plastic solar." In conventional solar cells, incoming solar energy is transferred to the electrons in a semiconducting material, such as silicon, which knocks many of them loose. These electrons are guided to an electrode, creating a current that can be drawn off and used.

The plastic solar movement aims to replace materials like silicon with polymer nanowires, which are cheaper and lighter. Another advantage of plastic solar cells is their physical versatility. Due to the flexible, bendable nature of polymer materials, plastic solar cells could be placed in areas of greatly varying size and surface type. Conventional cells are rigid and costly, and the current production method limits their size.

In plastic solar cells constructed to date, electrons must jump from one polymer wire to another in order to reach the electrodes. But as the electrons leave one wire in order to jump to the next, they encounter barriers, which require larger amounts of energy to traverse than the barriers that hinder electron movement within typical nanowires. This slows down the electrons.

Miller and his collaborators want to learn how to eliminate the barriers. But first, they must understand how the electrons move within single polymer wires -- the amount of energy the electrons need, for example. Later, this information can be used to choose the best polymer conductors and design structures for plastic solar cells.

The group observed electrons move down a polymer wire by immersing the wire in an organic fluid and shooting high-energy electrons through the fluid. The electrons were supplied by Brookhaven’s Laser-Electron Accelerator Facility (LEAF), which accelerates electrons to high energies for research applications. The energetic LEAF electrons either kick away some of the fluid molecules’ electrons or allow the molecules to give up "holes" -- mobile, empty spaces that carry positive charge. As a result, the submerged nanowire receives one of these electrons or holes.

"This new method injects extra negative or positive charges into the wires and allows us to observe the charges quickly diffuse across it. This observation is a key step toward developing polymer nanowires that are good conductors," Miller said.

In the future, Miller and his group also plan to look for ways to increase the conduction efficiency of the wires.

Karen McNulty Walsh | EurekAlert!
Further information:
http://www.bnl.gov

More articles from Power and Electrical Engineering:

nachricht Researchers use light to remotely control curvature of plastics
23.03.2017 | North Carolina State University

nachricht TU Graz researchers show that enzyme function inhibits battery ageing
21.03.2017 | Technische Universität Graz

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>