Researcher Min Cai creates a metal-oxide based OLED.
Credit: Courtesy of the DOE Ames Laboratory Researcher Min Cai creates a metal-oxide based OLED.

Solid-state lighting technology takes advantage of a large number of materials, including rare substances such as indium. Indium tin oxide (ITO), a standard material used for the anode layer of organic light-emitting diodes (OLEDs), is considered problematic due to its limited supply, as well as its fragility and inflexibility in OLED components.

Researchers at the U.S. Department of Energy’s (DOE) Ames Laboratory have found a suitable alternative to ITO in the form of a common polymer known as PEDOT:PSS. Although the plastic previously lacked acceptable transparency for use as an anode material in OLEDs, the scientists developed a multilayering process with additional treatments to improve its properties for such an application. In addition, the Ames team’s surrogate material outperformed ITO in laboratory tests. “Compared to an ITO anode device, the PEDOT:PSS device is at least 44 percent more efficient,” said Min Cai, a post-doctoral researcher at Iowa State University.

The development should result in less expensive, more resilient OLEDs that minimize the need for rare earth metals in their manufacture.

Blaine Brownell, AIA, is a regularly featured columnist whose stories appear on this website each week. His views and conclusions are not necessarily those of ARCHITECT magazine nor of the American Institute of Architects.