Bringing blue light with green light material to extend OLED life

White light is the star of tomorrow's lighting technology. The US Department of Energy (DOE) predicts that in 2020, the cost, efficiency and longevity indicators of OLED lighting will be inconsistent with LED! However, the industry is currently suffering from the short life of organic light-emitting blue phosphorous materials. The OLED luminescent layer is mainly composed of red fluorescent material, green light material and blue phosphor material mixed into white light. The decay of the life of one material will make the whole OLED fail. How to overcome the material life is different and become an industrial challenge. problem.

The Institute of Technology developed the "OLED surface plasma coupling gain technology" to convert the light-emitting spectrum of green light materials into blue light, breaking through the bottleneck of the short life of organic blue light-emitting materials. (All image sources: ITRI)

The solution to the "Blu-ray" of the Institute of Technology, that is, without using any blue light material, is to use the technology to make the green light material a source of blue light, thereby developing the OLED surface plasma coupling gain technology PCOLED (Plasmon-Coupled Organic) LED).

When the Taiwan Institute of Technology was conducting experiments on the light-emitting structure of green light materials, it was found that the green light material actually emitted the impossible blue light, which enabled the ITRI to open a new research direction, and later used physical thinking to design green light materials. The special structure, constantly adjusting the parameters, finally found out and summarized the reason and method of the blue light emitted by the green light material.

Finally, the DML structure is used to generate the planar plasma coupling effect (Plasmon-Coupled), which can convert the luminescent spectrum of the green material into blue light. The white OLED can replace the traditional blue material layer with the green light material, which not only has a short life span. It can be solved even more than 20 times longer than traditional OLEDs.

In terms of efficiency, through continuous research and development and component optimization, DML blue light emission efficiency can exceed the level of existing blue fluorescent materials and most known blue phosphorescent materials, up to 35cd/A. OLED DML white light technology has been proven to emit white light with a color rendering (CRI) of 77 and a color temperature of 2039 K, which can be used for indoor lighting, and ITRI has successfully illuminated a large white light module of 10 cm x 10 cm.

At present, the ITRI team has applied for patents in Taiwan, Germany, the United States and mainland China, and has cooperated with non-governmental enterprises to further master key OLED materials and process technologies, and to move toward industrialization.