Researchers are developing a faster and cheaper way to print tiny metal structures with light

Researchers at the Georgia Institute of Technology have developed a light-based method for printing nanoscale metal structures that is significantly faster and cheaper than any currently available technology. It's a scalable solution that could transform a scientific field that has long relied on prohibitively expensive and slow technologies. This breakthrough has the potential to bring new technologies out of the lab and into the world.

Technological advances in many fields rely on the ability to print nanoscale metal structures – hundreds of times smaller than the width of a human hair. George W. Saurabh Saha, an assistant professor in the Woodruff School of Mechanical Engineering, and Jungo Choi, a Ph.D. student in Saha's lab developed a technique for printing metal nanostructures that is 480 times faster and 35 times cheaper than the current conventional method.

Their study Published In the journal Advanced Materials.

Printing metal at the nanoscale – a technique known as nanopatterning – allows us to create unique structures with interesting functions. It is important for the development of many technologies including electronic devices, solar energy conversion, sensors and other systems.

It is generally believed that high-intensity light sources are required for nanoscale printing. But this type of equipment, called a femtosecond laser, costs up to half a million dollars and is too expensive for most research labs and small businesses.

„As a scientific community, we lack the ability to make these nanomaterials quickly and cheaply, which is why promising technologies are often limited to the lab and never translate into real-world applications,” Saha said. .

„The question we wanted to answer was, 'Do we really need a high-intensity femtosecond laser for nanoscale printing?' Our hypothesis is that we don't need those light sources to get the type of printing we want.”

They sought low-cost, low-intensity light that could be focused like femtosecond lasers, and chose superluminescent light-emitting diodes (SLEDs) for their commercial availability. SLEDs emit a billion times less intense light than femtosecond lasers.

Saha and Choi began developing the original projection-style printing technology, designing a system that converts digital images into optical images and displays them on a glass surface. Computers work like digital projectors, but produce images that are much more sharply focused. They used the unique properties of superluminescent light to produce sharply focused images with minimal defects.

They then created a clear ink solution made of metal salts and added other chemicals to ensure the liquid absorbed light. When light from their projection system hit the solution, it caused a chemical reaction that turned the salt solution into metal. Metal nanoparticles adhere to the surface of the glass, and the aggregation of metal particles forms nanostructures. Since it's a projection type of printing, it can print an entire structure at once, rather than point-to-point, making it much faster.

After testing the technique, they found that projection-style nanoscale printing is possible even with low-intensity light, but only if the images are sharply focused. Saha and Choi believe the researchers can readily replicate their work using commercially available hardware. Unlike the expensive femtosecond laser, the type of SLED that Saha and Choi used in their printer costs about $3,000.

„Currently, only top universities have access to these expensive technologies, and they are located in shared facilities and are not always available,” Choi said. „We want to democratize the potential of nanoscale 3D printing, and we believe our research will open the door to greater access to this type of process at a lower cost.”

The researchers say their technique could be particularly useful for people working in the fields of electronics, optics and plasmonics, all of which require a variety of complex metal nanostructures.

„I think the metrics of cost and speed are greatly underestimated in the scientific community working on developing and manufacturing small structures,” Saha said.

„In the real world, these metrics are important when translating discoveries from the lab to industry. Only if we have manufacturing techniques that take these metrics into account can nanotechnology be fully used for societal benefit.”