Engineers develop transistors that can be bent, stretched, and even crumpled up

Engineers develop transistors that can be bent, stretched, and even crumpled up

Breakthrough in nanotechnology opens door to plenty of possible uses

BY JEFFREY BAUSCH

Engineers from the University of Tokyo and the Tokyo University of Science have successfully built carbon nanotube-based transistors that are thin, strong, and display a unique ability to still work despite being crumpled up.

A team of engineers developed a field effect transistor that can be crumpled up.

It’s the latest breakthrough in the rapidly evolving field of nanotechnology, which has seen innovations ranging from spray-on antennas to paint-on solar cells to skin-like sensors for robots and patients with prosthetics all developed over the last few months.

How they did it

The field-effect transistors (FET) were built with single-walled carbon nanotubes. As a matter of fact, all components within the device (active channel, electrodes, dielectric layer, and substrate) consisted of carbon-based materials.

The team found that using a plastic substrate allowed the device to be extremely deformable. They were actually able to fold the device to the point where the radius of the material’s bend was just one millimeter. Obviously, this isn’t a “true” fold, but hey, it’s pretty close.

What’s particularly noteworthy about their research is the fact that the transistor’s circuits are completely transparent. This means that the transistor itself can be bent, stretched, or crumpled up, then applied, and you won’t even see that it’s there.

Why is this is a big deal? In the past, if you wanted a clear, flexible FET, you needed to use gold or indium tin oxide as electrodes. The problem with this is twofold: gold, obviously, isn’t transparent, and indium tin oxide is actually a pretty brittle material. Hence the need for an FET like the one this team has put together here.

Crumpling it up

The FET measures 15 micrometers thick. It can be crumpled up 100 times before it starts to lose some of its performance which, really, shouldn’t come as that big of a surprise — the drop in charge is simply a direct result of the carbon tubes being broken down so many times. As material research continues, we’ll likely see the durability of these FETs grow exponentially.

Outlook

There are a ton of uses out there for a bendable, flexible, crumple-able FET. You can stick it to surfaces where electronics are not normally applied. You can also apply it to flexible materials that might benefit from having a little extra charge to it (like, say, bioelectric bandages).

Published study

The team’s paper is entitled Deformable transparent all-carbon-nanotube transistors . It was published with the American Institute of Physics and is available for purchase.

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