A new structural view of organic electronic devices
Although still in the qualifying rounds, U.S. researchers are helping manufacturers win the race to develop low-cost ways to commercialize a multitude of products based on inexpensive organic electronic materials -- from large solar-power arrays to electronic newspapers that can be bent and folded.
In the on-line issue of Advanced Materials,* researchers from the National Institute of Standards and Technology (NIST) and the University of California at Berkeley report success in using a non-destructive measurement method to detail three structural properties crucial to making reliable electronic devices with thin films of the carbon-rich (organic) semiconductors. The new capability could help industry clear hurdles responsible for high manufacturing development costs that stand in the way of widespread commercial application of the materials.
With the technique called near-edge X-ray absorption fine-structure spectroscopy, or NEXAFS, the team tracked chemical reactions, molecular reordering and defect formation over a range of processing temperatures.
They then evaluated how process-induced changes in thin-film composition and structure affected the movement of charge carriers (either electrons or electron "holes") in organic field effect transistors, devices basic to electronic circuits. With NEXAFS measurements taken over the range from room temperature to 300 degrees Celsius, the team monitored the conversion of a precursor chemical to an oligothiophene, an organic semiconductor. The molecular organization and composition achieved at 250 degrees Celsius yielded the highest levels of charge carrier movement and, consequently, maximum electric-current flow.
As chemical conversion progressed, the researchers calculated how the molecules arranged themselves on top of an electrical insulator. Top transistor performance corresponded to a vertical alignment of molecules. In addition, they used NEXAFS to determine the angles of chemical bonds and to assess the thickness and uniformity of film coverage, also critical to performance.
NEXAFS has the potential to be the "ideal measurement platform for systematic investigation" of organic electronic materials, says lead investigator Dean DeLongchamp, a NIST materials scientist. "A straightforward means of correlating chemical and physical structure to the electronic performance of organic semiconductor films is a much-needed tool."
* D.M. DeLongchamp, S. Sambasivan, D.A. Fischer, E.K. Lin, P. Chang, A.R. Murphy, J.M.J. Frechet, and V. Subramanian, "Direct Correlation of Organic semiconductor film structure to field-effect mobility," Advanced Materials, published online Aug. 30, 2005, DOI number (10.1002/adma.200500253).
Source: NIST
-
From lemons to lemonade: Reaction uses carbon dioxide to make carbon-based semiconductor,
32 comments
-
Thioridazine kills cancer stem cells in human while avoiding toxic side-effects of conventional cancer treatments,
3 comments
-
SpaceX private rocket blasts off for space station (Update),
42 comments
-
Climate scientists say they have solved riddle of rising sea,
31 comments
-
SpaceX capsule has 'new car' smell, astronauts say (Update),
4 comments
More news stories
Is a classical electrodynamics law incompatible with special relativity?
(Phys.org) -- The laws of classical electromagnetism that were developed in the 19th century are the same laws that scientists use today. They include Maxwell’s four equations along with the Lorentz la ...
May 24, 2012 |
4.7 / 5 (18) |
43
|
Landmark calculation clears the way to answering how matter is formed
(Phys.org) -- An international collaboration of scientists, including Thomas Blum, associate professor of physics, is reporting in landmark detail the decay process of a subatomic particle called a kaon – ...
May 25, 2012 |
4.3 / 5 (22) |
53
|
Lying in wait for WIMPs: Researchers seek to dramatically increase sensitivity of Large Underground Xenon detector
Although it's invisible, dark matter accounts for at least 80 percent of the matter in the universe. No one knows what it is, but most scientists would bet on weakly interacting massive particles, or WIMPs.
May 23, 2012 |
4 / 5 (7) |
18
|
Hawaii lab turns laser-powered bubbles into microrobots
(Phys.org) -- A team of scientists from the University of Hawaii are working on microrobots created from bubbles of air in a saline solution. The bubbles take on their title of “robots” as a laser ...
May 23, 2012 |
5 / 5 (4) |
2
|
Sound increases the efficiency of boiling
Scientists at the Georgia Institute of Technology achieved a 17-percent increase in boiling efficiency by using an acoustic field to enhance heat transfer. The acoustic field does this by efficiently removing vapor bubbles ...
May 24, 2012 |
5 / 5 (2) |
2
'Unzipped' carbon nanotubes could help energize fuel cells, batteries
Multi-walled carbon nanotubes riddled with defects and impurities on the outside could replace some of the expensive platinum catalysts used in fuel cells and metal-air batteries, according to scientists at ...
Change in developmental timing was crucial in the evolutionary shift from dinosaurs to birds: study
At first glance, it's hard to see how a common house sparrow and a Tyrannosaurus Rex might have anything in common. After all, one is a bird that weighs less than an ounce, and the other is a dinosaur that ...
Computer model used to pinpoint prime materials for efficient carbon capture
When power plants begin capturing their carbon emissions to reduce greenhouse gases – and to most in the electric power industry, it's a question of when, not if – it will be an expensive undertaking.
T cells 'hunt' parasites like animal predators seek prey, study shows
By pairing an intimate knowledge of immune-system function with a deep understanding of statistical physics, a cross-disciplinary team at the University of Pennsylvania has arrived at a surprising finding: T cells use a movement ...
Stunning image of smallest possible five-ringed structure
Scientists have created and imaged the smallest possible five-ringed structure – about 100,000 times thinner than a human hair – and you'll probably recognise its shape.
Land and sea species differ in climate change response: study
(Phys.org) -- Marine and terrestrial species will likely differ in their responses to climate warming, new research by Simon Fraser University and Australia’s University of Tasmania has found.
