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Organic Light-Emitting Diodes Replace Indium-Oxide in Screen Displays


A breakthrough development emerged from the U.S Department of Energy’s (DOE) Ames Laboratory. Scientists have discovered a way to replace breakable metal-oxide, indium tin oxide, used in screen displays in computers, TVs and cell phones, with a polymer in organic light emitting diodes (OLEDs).

The findings were recently published in the journal Advanced Materials, with lead authors Joseph Shinar and Ruth Shinar, together with a team of researchers from Ames.

The limited supply of Indium brings up his cost, at a time when the demand for screen and lighting technology is rapidly growing. Indium is listed as a “near-critical” material with high importance to clean energy technology.

Joseph Shinar, an Ames Laboratory Senior Scientist comments that not many elements are able to replace the element considering its specific transparency and electroconductivity, however the scientific community has been working for quite some time now to find the suitable alternative.

Min Cai, a post-doctoral research scientist in the Ames Laboratory and the Dept. of Physics and Astronomy at Iowa State University, adds that while many are testing the use of zinc oxide, the team at Ames have focused on testing a conducting polymer.

This polymer has been around for more than 15 years and it is called poly (3,4-ethylene dioxythiophene):poly(styrene sulfonate), also known as PEDOT:PSS. The team applied a multi-layering technique and special treatment to produce the so-called PEDOT:PSS OLEDs, which has sufficient conductivity and transparency.
When compared with an ITO anode, Cai estimated that the EDOT:PSS device is 44% more efficient. Joe Shinar stated that this increase places this alternative higher on the list than any ITO-based technology. The improved performance is accounted to the difference in optical properties and flexibility of the polymer.

The flexibility is one of the principle advantages of OLEDs over LEDs, however ITOs are brittle rather than flexible, according to Ruth Shinar, a Senior Scientist at Iowa State University’s Microelectronics Research Center.

OLED screen TVs have already been sold to some lucky few customers, however Joseph Shinar predicts that prices will eventually go down and more people would be able to afford them, as Samsung and LG are already implementing the technology.

This technology is also getting more regularly used in lightning as well as in architectural and art designs.

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