KAIST researchers have reportedly developed a technology for fabricating high-performance organic light emitting diodes (OLEDs) on thinner fibers than hair, according to an article from ETNews of South Korea. The fabrication method utilizes a “dipcoating process” which Choi Kyung-cheol, professor of electrical engineering and electronics, and Dr. Kwon Sun Il, Ph.D. developed.
So far creating a wearable textile display is mostly a design concept that is beyond the fabrication capabilities of the best OLED fabricator. However, the KAIST development of an OLED that is woven into fabric brings this design concept closer to reality.
The researchers immersed the yarn in an organic solution to form the function OLED thin-film layer. So far, the device performance and durability were lower than those of the conventional flat OLED devices, and therefore the commercialization potential of the technology in its current iteration is limited.
KAIST Engineers Optimized Structure of Functional Layers
For the new dip coating process, the researchers reportedly simplified and optimized the structure of the functional layers. The method formed several functional layers and electron facilitated the transfer of the electron injection layer and the transport layer. Then, they used a method for adding various materials such as polyethylimine to improve electric performance.
Using these steps, the team succeeded in producing OLED materials with a luminance above 10,000 cd / m2 (m 2) that features an efficiency of 11 cd/ampere (A). The optimized functional layer also enhances the device’s durability. The OLED material maintained its performance despite a 4.3% luminance variation.
The KAIST engineers were also able to fabricate OLEDs on fibers made of 90 micrometers (㎛) of yarn that are thinner than human hair. They employed a process that generally uses a temperature of less than 105 degrees Celsius. Such a method could also be applied to thermally weak fibers.