Scientists create flexible LEDs that can be woven into fabric

Researchers at the Korea Advanced Institute of Science and Technology (KAIST) have created a fibre-like LED that can be woven into fabric. The technology could prove a significant breakthrough in the growing trend of wearable electronics.

"Our research will become a core technology in developing light emitting diodes on fibres, which are fundamental elements of fabrics," said Professor Choi, head of the research team at the School of Electrical Engineering at KAIST. "We hope we can lower the barrier of wearable displays entering the market."

To produce the LEDs, the scientists begin with a fiber of polyethylene terephthalate, which is then dipped into a solution of PEDOT:PSS and then left to dry at 130° C for 30 minutes to ready it for layering with organic materials. Once dried, the dipped fibre is then re-dipped in a bath of poly-p-phenylenevinylene polymer organic LED (OLED) solution, dried again in an oven, and finally coated with a Lithium Fluoride/Aluminum (LiF/Al) compound.

The researchers say this process is a more efficient way of applying LED materials to small cylindrical structures than any heat-treating method. By carefully adjusting the extraction rate of the fibre from the solution, the researchers say they can control the deposition thickness to within hundreds of thousandths of a nanometer.

The researchers believe their method of producing LED fibres could be an accelerator for the commercialisation of wearable displays because inexpensive, automated high-volume production of fibres using such textile manufacturing methods as roll-to-roll processing could be employed. In this way, LED fibres could be mass-produced as easily as nylon or polyethylene fibre is produced today.