Prof. Kyung-Chul Choi's Research Team has developed a technology to produce highly efficient organic light emitting diode (OLED) on fibers thinner than hair.
Conventional fiber-type wearable display research has focused on the implementation of the device, and therefore, it shows low performance compared to flat panel OLED devices in terms of performance and durability of devices. As a result, there was a limit to the practical application as a wearable display.
The team designed a OLED device structure suitable for the fiber to solve the problem, with using a dip coating process suitable for the three-dimensional fiber structure, and developed a high efficiency, long lifetime of OLEDs comparable to the flat panel production. With this technology, OLED structure using flat plate-based solution process can be applied to fiber as it is, without any deterioration of performance, with luminance of 11 cd/m2 and efficiency of 11 cd/A.
They also confirmed that fiber-type OLED performance is well maintained even at a mechanical strain of 4.3%, and they have also proved that fabricated OLEDs do not cause any problems when weaving into fabrics.
The technology developed by the researchers was able to form OLEDs from 300 micrometer (㎛) diameter fibers to 90 micrometer diameter fibers which is thinner than hair. In addition, all processes are carried out at a low temperature of 105°C or lower so it is also applicable to common fibers which are weak to heat.
This technology is expected to be a high efficiency, long lifetime fiber type OLED technology applicable to wearable display in the future.
The research, led by Sun Il Kwon (Ph.D candidate), was published online in the December 6 2017 issue of Nano Letters, an international journal in the field of nanoscience.