Materials: Fashioning semiconductor devices into smart clothing

Light-emitting diodes and sensors can be woven directly into textile-grade polymer fibres by means of a new fabrication method unveiled in this week’s Nature. The process could be used to create new forms of wearable technology capable of performing optical communication and health monitoring.

Semiconductor diodes that can emit or detect light are fundamental building blocks in communication and sensor technologies. Building them into fabrics could unlock a tapestry of new electronic wearables. It has proven knotty, however, to marry the function of semiconductor devices with the scalability of fibre-based textiles.

Yoel Fink and colleagues start with a larger polymer mass containing the semiconductor devices alongside a hollow channel. The material is heated and drawn out while wire is spooled into the channels, forming an extended strand of fibre with electrically connected diodes - either light-emitting or photodetecting - spaced out along its length. The process is inherently scalable, allowing the fashioning of hundreds of metres of these functional fibres. Once drawn, the fibres can be easily woven into fabric.

The authors demonstrate the durability of their diode fibres by running them through ten cycles in a standard, household washing machine, which did not negatively impact their performance. They also show that a two-way optical communication link can be established between two fabrics containing light-detecting and light-emitting fibres, and that the smart textiles can be used for measurements of the wearer’s heart rate.

The new manufacturing process provides a pattern from which to knit up fabrics with even more advanced functions, the authors conclude, opening up the potential for a Moore’s law analogue for smart textiles and wearable technologies of ever-increasing sophistication.