TMCnet Feature
October 02, 2013

Novel Wagon Wheel Pasta-shaped Molecules Make Organic LEDs More Efficient

By Ashok Bindra, TMCnet Contributor

To make organic light-emitting diode (OLED) based light bulbs and displays more efficient, scientists around the world have been struggling to overcome polarization, which traps light, within the LED diode. Now, physicists at the University of Utah claim to have resolved the problem by creating a new organic molecule that is shaped like wagon-wheel pasta rather than spaghetti.

ECN magazine reported that this new wagon wheel pasta-shaped molecule, known as a "pi-conjugated spoked-wheel macrocycle", acts the opposite of polarizing sunglasses, which screen out glare reflected off water and other surfaces and allow only direct sunlight to enter the eyes. Each wagon-wheel molecule measures only six nanometers wide, which is large for a molecule but tiny compared with the 100,000 nanometer width of a human hair.

The report shows that the wagon-wheel molecules emit light randomly in all directions, making OLEDs more efficient. Unlike existing OLEDs which are used in some smartphones and TVs, use spaghetti-shaped polymers which emit only polarized light.

Physicist John Lupton is the lead investigator of this study, which was published on the website of journal Nature Chemistry. “This work shows it is possible to scramble the polarization of light from OLEDs and thereby build displays where light doesn't get trapped inside the OLED," wrote Lupton.

As per Lupton’s explanation, the new molecule is perfectly symmetrical, which distributes the light more randomly, making it more efficient. “It holds promise for future OLEDs that would use less electricity and thus increase battery life for phones, and create OLED light bulbs that are more efficient and cheaper to operate."

The physicists thinks that today’s OLEDs used in smartphones, and super-thin TVs are expensive but more efficient than conventional liquid-crystal displays (LCDs) like the ones used in the iPhone (News - Alert).

A research Professor of Physics & Astronomy at the University of Utah, Lupton is also on the faculty of the University of Regensburg, Germany. He conducted the study with Utah physics graduate students Alexander Thiessen, Sigurd Höger, Vikas Aggarwal, Alissa Idelson, Daniel Kalle and Stefan-S. Jester of the University of Bonn. In addition, researchers Dominik Würsch, Thomas Stangl, Florian Steiner and Jan Vogelsang of the University of Regensburg also participated in this study.

The report indicates that the University of Utah study was funded by the Volkswagen Foundation, the German Chemical Industry Fund, the David and Lucille Packard Foundation and the European Research Council.

Edited by Ryan Sartor
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