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 How protons move through a fuel cell
22.06.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

nachricht Fraunhofer IZFP acquires lucrative EU project for increasing nuclear power plant safety
21.06.2017 | Fraunhofer-Institut für Zerstörungsfreie Prüfverfahren IZFP

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: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

Im Focus: Optoelectronic Inline Measurement – Accurate to the Nanometer

Germany counts high-precision manufacturing processes among its advantages as a location. It’s not just the aerospace and automotive industries that require almost waste-free, high-precision manufacturing to provide an efficient way of testing the shape and orientation tolerances of products. Since current inline measurement technology not yet provides the required accuracy, the Fraunhofer Institute for Laser Technology ILT is collaborating with four renowned industry partners in the INSPIRE project to develop inline sensors with a new accuracy class. Funded by the German Federal Ministry of Education and Research (BMBF), the project is scheduled to run until the end of 2019.

New Manufacturing Technologies for New Products

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

A new technique isolates neuronal activity during memory consolidation

22.06.2017 | Life Sciences

Plant inspiration could lead to flexible electronics

22.06.2017 | Materials Sciences

A rhodium-based catalyst for making organosilicon using less precious metal

22.06.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>