Ultra-thin, flexible silicon materials aren’t as durable as we’d hope. In response, Saudi researchers have developed a novel method for creating bendable and stretchable silicon-based electronics.
Imagine a smartphone that wraps around your wrist, a TV that you can roll up like a carpet, product packaging you can interact with or even workout clothes stuffed with sensors to help improve your physical fitness. In short, flexible electronics will undoubtedly change daily life in many ways.
With flexible electronics, there are no cracked screens or shorted audio jacks. In our new Internet of Things, wearables will be durable, practical, and resistant to the natural forces that make our current devices fall apart.
For the most part, new research into flexible electronics focuses on the use of polymer materials, which do boast some flexibility yet at the expense of superconducting power. Silicon has the advantage in that department.
There are also ultra-thin silicon substrates used to develop flexible electronics, but these still deal with extreme fragility. If a small part of a connector is damaged, the whole system fails.
Silicon-Based “Islands” Make the Most Flexible Electronics
Led by Muhammad Mustafa Hussain, Associate Professor at the King Abdullah University of Science and Technology in Saudi Arabia, researchers have taken this to the next step. A paper on the technique was published last month in the journal Applied Physics Letters.
They have designed flexible, stretchable, foldable, and tiny silicon “islands” which are interconnected via ultrathin silicon-based connectors. The islands provide mechanical support, while silicon springs provide flexibility.King Abdullah researchers developed durable, silicon-based flexible electronics.Click To Tweet
The 500-micrometer thick silicon islands form a stand-alone array that bends freely. The big challenge that faced researchers was the network of silicon springs that connect the islands, without which there would be no flexibility.
The 30-μm-thick silicon connectors had to be patterned in such a way that they could stretch to several times their original length and still don’t get tangled with each other. After considering many geometrical designs (spiral and fractal patterns), the researchers settled on the best design for the silicon springs. They mimicked spherulite-lamellar found in nature (a motif of radiating lines seen in rocks).
Experiments showed that with this pattern, the bending-induced strain would spread across the entire length of the spring, allowing the final device to stretch to more than five times its original area. The pattern also allows the islands in the silicon array to bend to a radius of 130 μm, regardless of the substrate thickness.