According to the researchers, the process is low-cost and combines tools already used in industry for manufacturing metals on a large scale - but, it uses the speed and precision of roll-to-roll newspaper printing to remove a couple of fabrication barriers in making electronics faster than they are today.
Many electronics, including mobiles and tablets, rely on their internal metallic circuits to process information at high speed. Current metal fabrication techniques tend to make these circuits by getting a thin rain of liquid metal drops to pass through a stencil mask in the shape of a circuit.
"Unfortunately, this fabrication technique generates metallic circuits with rough surfaces, causing our electronic devices to heat up and drain their batteries faster," said Assistant Professor Ramses Martine of Purdue University.
Future ultrafast devices will also require much smaller metal components, which calls for a higher resolution to make them at these nanoscale sizes, added the researchers.
"Forming metals with increasingly smaller shapes requires moulds with higher and higher definition, until you reach the nanoscale size," Assistant Prof. Martinez said. "Adding the latest advances in nanotechnology requires us to pattern metals in sizes that are even smaller than the grains they are made of. It's like making a sand castle smaller than a grain of sand."
This so-called "formability limit" hampers the ability to manufacture materials with nanoscale resolution at high speed.
Purdue researchers claim to have addressed both of these issues - roughness and low resolution - with a new large-scale fabrication method that enables the forming of smooth metallic circuits at the nanoscale using conventional carbon dioxide lasers.
"Printing tiny metal components like newspapers makes them much smoother. This allows an electric current to travel better with less risk of overheating," Assistant Prof. Martinez said.
The fabrication method, called roll-to-roll laser-induced superplasticity, uses a rolling stamp like the ones used to print newspapers at high speed, the researchers explained. The technique can induce, for a brief period of time, "superelastic" behaviour to different metals by applying high-energy laser shots, which enables the metal to flow into the nanoscale features of the rolling stamp - circumventing the formability limit.
"In the future, the roll-to-roll fabrication of devices using our technique could enable the creation of touch screens covered with nanostructures capable of interacting with light and generating 3D images, as well as the cost-effective fabrication of more sensitive biosensors," Assistant Prof. Martinez said.
