We’re all familiar with smart watches and similar devices that can display our heart rate, steps taken, calories consumed, and other health data LEDs or OLED displays. Advances in wearables now allow small, flexible organic light-emitting diodes (OLEDs) to be woven directly into fabric. One of the challenges with OLEDs, however, has been finding the kind of light emitters that will stand up to the performance requirements of wearable displays in woven clothing.
Fiber OLEDs that could be used to create light-emitting thread suffer from poor optical performance. Those built using wires require high temperatures to create, which is not compatible with the process used to manufacture garments. Now a team of researchers at the Korea Advanced Institute of Science and Technology (KAIST) has developed a high-luminance OLED fiber that can be made using a process that can be woven into textiles and knitted garments. Lead researcher Kyung Cheol Choi says these fiber OLEDs have the potential to overcome the performance issues of standard light-emitting fibers. The KAIST research team used a dip-coating method to deposit sequential, even layers of OLED components around a commonly used material for plastic fibers known as a polyethylene terephthalate (PET) substrate. The fibers were able to emit light even when bent and submitted to other flexibility tests. Researchers established that the fibers could be hand-woven into knitted garments.
Researchers call the process a “simple, cost-effective and low-temperature solution,” which makes wider commercialization of fiber-based wearable displays possible. It’s easy to imagine a day when you may literally wear your heart rate data on your sleeve.