A research team led by Professor Kyung Cheol Choi at the School of Electrical Engineering at KAIST in South Korea has developed wearable OLED (organic light-emitting diode) displays for various applications including fashion, IT, and healthcare.
The team used two different approaches, fabric-type and fibre-type, for clothing-shaped wearable displays. In 2015, the team successfully laminated a thin planarization sheet thermally onto fabric to form a surface that is compatible with the OLEDs approximately 200nm thick. Also, the team reported their research outcomes on enhancing the reliability of operating fibre-based OLEDs. In 2016, the team introduced a dip-coating method, capable of uniformly depositing layers, to develop polymer light-emitting diodes, which show high luminance even on thin fabric.
Working with local materials company KOLON Glotech, Seungyeop Choi used the resesearch to develop the fabric-based OLEDs, showing high luminance and efficiency while maintaining the flexibility of the fabric.
The long-term reliability of this wearable device that has the world's best electrical and optical characteristics was verified through their self-developed, organic and inorganic encapsulation technology. According to the team, their wearable device facilitates the operation of OLEDs even at a bending radius of 2mm.
"Having wavy structures and empty spaces, fibre plays a significant role in lowering the mechanical stress on the OLEDs," said Prof Choi. "Screen displayed on our daily clothing is no longer a future technology. Light-emitting clothes will have considerable influence on not only the e-textile industry but also the automobile and healthcare industries."
The team believes these OLEDs have the world's best luminance and efficiency and are the most flexible fabric-based light-emitting device among those reported.