The researchers of the University of Toronto have developed a flexible OLED on plastic which is the worlds most efficient flexible or bendable organic light emitting diode.
This result enables a flexible form factor, not to mention a less costly, alternative to traditional OLED manufacturing, which currently relies on rigid glass.
In these devices, multifunctional anode stacks, consisting of a high-index Ta2O5 optical coupling layer, electrically conductive gold layer and hole-injection MoO3 layer, are collectively optimized to achieve high efficiency. The maximum external quantum efficiency reaches 63% for green, which remains as high as 60% at >10,000 cd m–2.
The goal could be reached with the high-refractive index property previously limited to heavy metal-doped glass by using a 50-100 nanometre thick layer of tantalum(V) oxide (Ta2O5), an advanced optical thin-film coating material. This advanced coating technique, when applied on flexible plastic, allowed the team to build the highest-efficiency OLED device ever reported with a glass-free design.
Professor Zheng-Hong Lu says:
“For years, the biggest excitement behind OLED technologies has been the potential to effectively produce them on flexible plastic,”
Using plastic can substantially reduce the cost of production, while providing designers with a more durable and flexible material to use in their products.
The research, which was supervised by Professor Lu and led by PhD Candidates Zhibin Wang and Michael G. Helander, demonstrated the first high-efficiency OLED on plastic. The performance of their device is comparable with the best glass-based OLEDs, while providing the benefits offered by using plastic.
Creating the Digital Displays of Tomorrow from U of T Engineering on Vimeo.
