Researchers from the University of Utah, Bonn and Regensburg developed a new wagon-wheel (or rotelle-pasta) shaped OLED molecule that emits non-polarized (random) light.Those oligomers, or wrapped-up polymers may enable OLEDs more efficient than polymer based OLEDs (PLEDs).
The researchers explain that current poylmer OLED molecules (which are shaped like spaghetti pasta, to continue the same metaphore) emit polarized light. Some of that light get trapped inside the OLED device and this makes it less efficient. They say that up to 80% of the generated light may be trapped in the OLED because it is polarized.
The new "pi-conjugated spoked-wheel macrocycle" shaped molecules emits light in all directions randomly - unpolarized light. This should reduce trapped light to about 50% to 60% (down from 80% in polymers)
This technology is just at its beginning, and the researchers say it will take a long time before such molecules can be made commercially. They also say that this molecule design can be used in other applications such as solar-cells (OPVs), biological sensors and more.
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.