A polymer shaped like wagon-wheel pasta can emit light in all directions, significantly reducing the amount of light wasted in LEDs, the authors of a new paper say.
Stefan Jester/University of Bonn/University of Utah
Spaghetti or rotelle?
This is not a culinary question – it’s a materials science one, and answering it could bolster the battery life of future smartphones.
Right now, organic LEDs are made with repeated molecular units that look like a spaghetti noodle. The linear shape means that light can move in just one direction, allowing just 20 percent of the light to escape the LED and leaving the other 80 percent trapped inside.
And LEDs can do better, according to a new paper published in Nature Chemistry on Sunday that describes a round organic molecule that could make LEDs, already at the forefront of energy efficient, high-tech lighting, even more efficient.
The new shape for the cooked-up molecule still takes its cues from pasta. But, instead of spaghetti, this time it’s rotelle, also known as wagon-wheel pasta. This six nanometer wide, spoke-wheeled molecule can emit light in all directions, significantly reducing the amount of light wasted in LEDs, the authors say.
“OLEDs are yet efficient,” says Sigurd Höger, a researcher involved in synthesizing the rotelle-shaped molecule at the University of Bonn and an author on the paper. “However, there are some problems with the light that is trapped inside the device.”
“And maybe we can make them more efficient,” he said.
LEDs, or light emitting diodes, have found out a plum spot in the lighting market in recent years. They use just 25 percent of the energy that an incandescent bulb requires and last about 25 times longer. LEDs illuminate households, make street lamps glow, backlight smartphone screens, and ring in the New Year on the ball dropped in Times Square. They have, in short, come light years from the unappealing red spots that first blinked onto the market in the 1960s.