By Josh Perry, Editor
[email protected]

A new manufacturing process, called roll-to-roll laser-induced superplasticity, from engineers at Purdue University (West Lafayette, Ind.), similar to one used to print newspapers, produces smoother and more flexible metals to enhance the speed of modern electronics.

 
Roll-to-roll laser-induced superplasticity, a new fabrication method, prints metals at the nanoscale needed for making electronic devices ultrafast.
(Purdue University/Ramses Martinez)

According to a report from the university, the process utilizes tools that are standard for manufacturing metals on a large scale but adds the speed and precision of roll-to-roll printing. This avoids one of the current pitfalls of manufacturing metallic circuits by passing drops of liquid metal through a stencil, which is circuits with rough surfaces.

These rough circuits cause electronics to heat up and drain batteries faster. This new process smooths out the surfaces and also enables the production of metals in smaller shapes with higher resolution.

“Purdue researchers 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, which are already common for industrial cutting and engraving,” the article explained.

The technique uses a rolling stamp at high speed and the metals become temporarily elastic by applying high-energy laser shots that cause the metal to flow into the nanoscale features of the stamp.

The research was recently published in Nano Letters. The abstract read:

“This Letter describes a low-cost, scalable nanomanufacturing process that enables the continuous forming of thin metallic layers with nanoscale accuracy using roll-to-roll, laser-induced superplasticity (R2RLIS). R2RLIS uses a laser shock to induce the ultrahigh-strain-rate deformation of metallic films at room temperature into low-cost polymeric nanomolds, independently of the original grain size of the metal.

“This simple and inexpensive nanoforming method does not require access to cleanrooms and associated facilities, and can be easily implemented on conventional CO₂ lasers, enabling laser systems commonly used for rapid prototyping or industrial cutting and engraving to fabricate uniform and three-dimensional crystalline metallic nanostructures over large areas.

“Tuning the laser power during the R2RLIS process enables the control of the aspect ratio and the mechanical and optical properties of the fabricated nanostructures. This roll-to-roll technique successfully fabricates mechanically strengthened gold plasmonic nanostructures with aspect ratios as high as 5 that exhibit high oxidation resistance and strong optical field enhancements.

“The CO₂ laser used in R2RLIS can also integrate the fabricated nanostructures on transparent flexible substrates with robust interfacial contact. The ability to fabricate ultrasmooth metallic nanostructures using roll-to-roll manufacturing enables the large-scale production, at a relatively low-cost, of flexible plasmonic devices toward emerging applications.”