Using a process that mimics the same imprint processes used by credit card manufacturers, researchers at Sandia National Laboratories have created a method to fabricate nanowires or other nano-sized components in a fraction of the time compared to chemical methods.
The process, called stress-induced fabrication, uses pressure to fabricate nanoparticles into nanowire-array structures similar to those that reside on the surface of touchscreens for sensors, computers, phones and TVs. The method is nine million times faster than any known chemical method when performed on Sandia’s Veloce pulsed-power machine, which generates pressures on the order of 100,000 atmospheres, Sandia says.
Sandia says embossing machines that are already in use for manufacturing could be used for this new method. “It's conceivable that few modifications would be needed to convert the machines from embossing to fabrication," says Hongyou Fan, a researcher at Sandia.
The advantages of this method include:
- Saving time as chemical methods can take up to hours.
- Less harmful to the environment as there are no chemicals to clean up.
- Saves material as the exact amount is only needed on the substrate.
- Reduction of defects in industrial chemical fabrication.
The process can fabricate a wide variety of nanoscale components such as nanorods and nanosheets. The components are able to be organized during their formation or dispersed in solvents for later assembly, Sandia says. This method could be used for future chemical sensors, strain detectors and electrodes in solar cells.
An earlier version of the process involved using a hand-tightened vise with diamond anvils but the tool was not rapid or malleable enough for commercial production. Industrial embossing machines, however, provide sufficient pressure and are controllable.
“For a touchscreen, the pressure has to be worked out beforehand to stop the compression at just the right distance from the target: not too far, not too close, to produce the underlying nanowiring for a flat screen,” Fan says. “It's a matter of programming the force applied to precisely determine how much to compress.”