Cheaper, more efficient OLEDs - just add chlorine


April 14, 2011

L to R: Zhibin Wang (PhD Candidate), Professor Zheng-Hong Lu, and Michael Helander (PhD Candidate   Vanier Canada Graduate Scholar) hold their Cl-ITO enabled OLED devices

L to R: Zhibin Wang (PhD Candidate), Professor Zheng-Hong Lu, and Michael Helander (PhD Candidate Vanier Canada Graduate Scholar) hold their Cl-ITO enabled OLED devices

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A team of researchers from the University of Toronto has developed a new technique to produce OLED devices that they say will accelerate the adoption of OLED technology into mainstream flat-panel displays and other lighting technologies. The process involves engineering a one-atom thick sheet of chlorine onto the surface of an indium tin oxide (ITO) material, which is used as a standard electrode material in today's flat panel displays. The end result is an OLED device that is not only more efficient, but also simpler and cheaper to produce.

The one-atom thick layer of chlorine is applied to the surface of ITO using a UV light assisted process that negates the need for chlorine gas, which the researcher point out makes the process safe and reliable. The resultant chlorinated ITO material allows for the efficient transport of electrons, while eliminating the need for several costly layers found in conventional OLED devices.

In tests that pitted their green-emitting "Cl-OLED" against a conventional OLED, the researchers found that the efficiency of their device was more than double that of conventional OLEDs at very high brightness. Although OLEDs are recognized for their high-efficiency, which is much greater than LCD, as the brightness is increased, the efficiency drops off dramatically. With the chlorinated ITO, the researchers were able to prevent this drop off and achieve a record efficiency of 50 percent at 10,000 cd/m2, which is more than twice as efficient as conventional OLEDs.

"Our Cl-ITO eliminates the need for several stacked layers found in traditional OLEDs, reducing the number of manufacturing steps and equipment, which ultimately cuts down on the costs associated with setting up a production line," says the University of Toronto's Professor Zheng-Hong Lu, who led the research. "This effectively lowers barriers for mass production and thereby accelerates the adoption of OLED devices into mainstream flat-panel displays and other lighting technologies," Lu added.

We can only hope he's right, because after seeing a few OLED displays at trade-shows over the past couple of years, we've been anxiously awaiting the arrival of OLED TV's that are cheaper and offer bigger screen sizes than the previous offerings from the likes of LG and Sony.

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

Exciting! The sooner we get more efficient displays and lighting, and the more widespread, the better


Go UofT! Keep the good developments coming!

Jeremy Nasmith

Except that iridium is a (astoundingly) rare earth element which is becoming scarcer and scarcer each year, with annual tonnage extracted from the earth less than 800 tons, down from over 1100 tons the year before. That\'s 800 tons of absolutely essential iridium for EVERYONE. Every computer, every game console, every phone requires iridium to function. All throw-away items which virtually no one extracts the processed iridium from.

Rolf Hawkins

Puts China in an incredible bargaining position with the rest of the world...

America won\'t like that..

Stuart Halliday

@Rolf Hawkins: In the article they mention indium, not iridium. I\'m not a chemist so I don\'t know the difference, apart from the number of letters in the word!



Gentlemen... The article mentions indium, NOT iridium. Indium is a byproduct of Zinc processing. China does not have a monopoly on Zinc processing, although they are involved in that venture as well. Canada is currently the leading producer of indium followed by Bolivia. Indium ranks 61st in abundance in the Earth\'s crust which means it is more than three times as abundant as silver,

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