Chlorine could hold the key to more efficient OLEDs and usher in a new generation of flat-panel displays. Researchers at the University of Toronto have engineered a one-atom thick sheet of chlorine onto the surface of existing industry standard electrode material, found in today’s flat panel displays. In doing so they created a medium that allows for efficient electrical transport while eliminating the need for several costly layers found in traditional OLED devices.
Professor Zheng-Hong Lu of the Department of Materials Science & Engineering at the Canadian University led primary researchers, Michael G. Helander and Zhibin Wang, in the research.
“It turns out that it’s remarkably easy to engineer this one-atom thick layer of chlorine onto the surface of ITO,” said Helander. “We developed a UV light assisted process to achieve chlorination, which negates the need for chlorine gas, making the entire procedure safe and reliable.”
The team tested their green-emitting “Cl-OLED” against a conventional OLED and found that the efficiency was more than doubled at very high brightness. “OLEDs are known for their high-efficiency,” says Helander. “However, the challenge in conventional OLEDs is that as you increase the brightness, the efficiency drops off rapidly.”
This drop off was prevented with the chlorinated ITO and record efficiency, of 50% at 10,000 cd/m² was achieved. The team claims this is at least two times more efficient than conventional OLED.
“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 Professor Zheng-Hong Lu.
“This effectively lowers barriers for mass production and thereby accelerates the adoption of OLED devices into mainstream flat-panel displays and other lighting technologies.”