KAIST fiber PLED

This picture may not be all that compelling at first glance. It looks like someone has a wire with some white stuff on it. Or maybe the wire is glowing from electricity running through it. Here’s the scoop; that white section is indeed emitting light, but there’s no wire involved. This is a piece of thread.

Researchers at the Korea Advanced Institute of Science and Technology (KAIST) presented a poster at the recent Society for Information Display’s international Display Week 2015. They describe how they created a fiber that emits light using polymer OLED (PLED) technology. They also used a transparent conductive polymer designed for printed electronics applications. The interesting part is that they simply dipped the fiber into the conductor and then the PLED materials. They then applied an aluminum electrode layer with a lithium-fluoride coating using thermal evaporation techniques.

The result was a thread that lit up at an impressive 900 cd/m^2. As a means of comparison, a typical desktop LCD monitor has is about 200 to 250 cd/m^2 light output and sunlight-readable displays for ATMs and other digital signage applications come in at about 1,000 cd/m^2. So this thread puts out a lot of light, at least in the lab. The important take-away here is that the fabrication process is relatively simple and could easily be adapted to roll-to-roll (R2R) production to create high speed and low cost production. These threads could form the basis for displays woven directly into the fabric of a garment. This could lead to devices that could display information based on the wearer’s biometric data in real time. You might say that people could actually wear their heart on their sleeve — or at least information about their heart — if they wanted.