The Max Planck Institute for Polymer Research has developed a prototype of a single-layer OLED, portending a much-needed reduction in manufacturing costs over today’s OLEDs, which are multilayered.
Using a decades-old technology called thermally activated delayed fluorescence (TADF), a team from the Mainz, Germany-based center achieved a lifetime of 2000 hours, in which the brightness declined by 50%.
“Now we hope to further improve the concept and achieve even longer lifetimes,” said team leader Dr. Gert-Jan A. H. Wetzelaer. “This would allow the concept to be used for industrial purposes.”
A single layer could dramatically lower the costs of putting together what is typically five to seven layers, some of which are used to transport charges, others to put electrons into the active layer that generates light.
The team published their single-layer findings in the journal Nature Photonics.
OLEDs are thin sheets of material that illuminate in response to an electric current, which is different from LEDs’ single light points.
Enthusiasts have long said that OLEDs will literally overhaul the fabric of lighting, as they can be woven in either rigid or flexible form into everything from bridges to buildings to clothing to you name it.
But they have proven costly to manufacture. The Max Planck work could help to remedy that.
OLEDs have also trailed LEDs in energy efficiency. But in another recent development, a team at Penn State launched a two-year program aimed at improving that. OLEDs also tend to not last as long as LEDs.
Another factor holding back OLEDs as a general lighting source is that LED manufacturers have improved designs that embed LEDs into thin sheets and thus mimic the effect of OLEDs.
MARK HALPER is a contributing editor for LEDs Magazine, and an energy, technology, and business journalist (email@example.com).