Materials science and engineering researchers at the University of Toronto have developed the world's most efficient organic light emitting diodes (OLEDs) on plastic. This paves the way for a flexible form factor as well as a less costly alternative to conventional OLED manufacturing, which is currently based on rigid glass substrates.
OLEDs enable high-contrast, low-energy displays that are rapidly becoming the dominant technology for advanced electronic screens. They are already used in some mobile phones and small-scale applications, and increasingly in general lighting applications. Current state-of-the-art OLEDs are produced using glass doped with heavy metals to achieve high efficiency and brightness, which makes them expensive to manufacture, heavy, rigid and fragile. Using plastic can substantially reduce production costs while providing designers with a more durable and flexible material for their products.
The research demonstrated the first high-efficiency OLED on plastic. The performance of their device is comparable with that of the best glass-based OLEDs, while providing the benefits offered by using plastic. The researchers were able to replicate the high refractive index property previously limited to glass with heavy-metal doping by using a 50–100 nm layer of tantalum(V) oxide (Ta2O5), an advanced optical thin-film coating material. In combination with a flexible plastic substrate, this coating technology allowed the team to build the highest-efficiency OLED device ever reported with a glass-free design.
The results of the research are reported online in the latest issue of Nature Photonics.
Image: University of Toronto (Engineering)