Polymer scientists and chemists combined to uncover a new discovery that may lead to more efficient and cost-effective material for use in cell phones, laptops, lasers, LED lights and fiber optic communications.
According to a University of Massachusetts Amherst report in the latest Nature Communications, researchers said that they had identified a property in an organic semiconductor molecule. That property, directional intrinsic charge separation, was found in crystalline nanowires of an organic semiconductor known as 7,8,15,16 tetraazaterrylene.
Physical chemist Michael Barnes and polymer scientist Alejandro Briseno worked with doctoral students Sarah Marques, Hilary Thompson, Nicholas Colella and postdoctoral researcher Joelle Labastide. Their study found a specific directionality of the charges in TAT, which Barnes said could be used for applications in which devices use polarized light for optical switching.
“Observing the intrinsic charge separation doesn't happen in polymers, so far as we know it only happens in this family of small organic molecule crystalline assembles or nanowires. In terms of applications we are now exploring ways to arrange the crystals in a uniform pattern and from there we can turn things on or off depending on optical polarization, for example,” said Barnes in a statement.
Barnes said in a phone interview that the result was “really quite a surprise and something that has not been seen before.”
He said that similar observations have been seen in pentacene crystals which did not show directionality So, other materials may have a similar property and that is something other researchers might build on.
The UMass Amherst team is supported by the U.S. Department of Energy and the UMass Amherst Center for Hierarchical Manufacturing. Their proposal is that a charge transfer interaction in the molecule's nanowires can be programed.
The discovery came about when Briseno and colleagues reached a point in synthesizing crystals where their polymer-based devices were not performing the way they wanted. Barnes and his team used special measurement instruments to investigate and found a fixable structural defect.
